Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * linux/fs/namei.c |
| 3 | * |
| 4 | * Copyright (C) 1991, 1992 Linus Torvalds |
| 5 | */ |
| 6 | |
| 7 | /* |
| 8 | * Some corrections by tytso. |
| 9 | */ |
| 10 | |
| 11 | /* [Feb 1997 T. Schoebel-Theuer] Complete rewrite of the pathname |
| 12 | * lookup logic. |
| 13 | */ |
| 14 | /* [Feb-Apr 2000, AV] Rewrite to the new namespace architecture. |
| 15 | */ |
| 16 | |
| 17 | #include <linux/init.h> |
Paul Gortmaker | 630d9c4 | 2011-11-16 23:57:37 -0500 | [diff] [blame] | 18 | #include <linux/export.h> |
David S. Miller | 4469690 | 2012-05-23 20:12:50 -0700 | [diff] [blame] | 19 | #include <linux/kernel.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 20 | #include <linux/slab.h> |
| 21 | #include <linux/fs.h> |
| 22 | #include <linux/namei.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 23 | #include <linux/pagemap.h> |
Robert Love | 0eeca28 | 2005-07-12 17:06:03 -0400 | [diff] [blame] | 24 | #include <linux/fsnotify.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 25 | #include <linux/personality.h> |
| 26 | #include <linux/security.h> |
Mimi Zohar | 6146f0d | 2009-02-04 09:06:57 -0500 | [diff] [blame] | 27 | #include <linux/ima.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 28 | #include <linux/syscalls.h> |
| 29 | #include <linux/mount.h> |
| 30 | #include <linux/audit.h> |
Randy Dunlap | 16f7e0f | 2006-01-11 12:17:46 -0800 | [diff] [blame] | 31 | #include <linux/capability.h> |
Trond Myklebust | 834f2a4 | 2005-10-18 14:20:16 -0700 | [diff] [blame] | 32 | #include <linux/file.h> |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 33 | #include <linux/fcntl.h> |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 34 | #include <linux/device_cgroup.h> |
Al Viro | 5ad4e53 | 2009-03-29 19:50:06 -0400 | [diff] [blame] | 35 | #include <linux/fs_struct.h> |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 36 | #include <linux/posix_acl.h> |
Linus Torvalds | 99d263d | 2014-09-13 11:30:10 -0700 | [diff] [blame] | 37 | #include <linux/hash.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 38 | #include <asm/uaccess.h> |
| 39 | |
Eric Paris | e81e3f4 | 2009-12-04 15:47:36 -0500 | [diff] [blame] | 40 | #include "internal.h" |
Al Viro | c710536 | 2011-11-24 18:22:03 -0500 | [diff] [blame] | 41 | #include "mount.h" |
Eric Paris | e81e3f4 | 2009-12-04 15:47:36 -0500 | [diff] [blame] | 42 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | /* [Feb-1997 T. Schoebel-Theuer] |
| 44 | * Fundamental changes in the pathname lookup mechanisms (namei) |
| 45 | * were necessary because of omirr. The reason is that omirr needs |
| 46 | * to know the _real_ pathname, not the user-supplied one, in case |
| 47 | * of symlinks (and also when transname replacements occur). |
| 48 | * |
| 49 | * The new code replaces the old recursive symlink resolution with |
| 50 | * an iterative one (in case of non-nested symlink chains). It does |
| 51 | * this with calls to <fs>_follow_link(). |
| 52 | * As a side effect, dir_namei(), _namei() and follow_link() are now |
| 53 | * replaced with a single function lookup_dentry() that can handle all |
| 54 | * the special cases of the former code. |
| 55 | * |
| 56 | * With the new dcache, the pathname is stored at each inode, at least as |
| 57 | * long as the refcount of the inode is positive. As a side effect, the |
| 58 | * size of the dcache depends on the inode cache and thus is dynamic. |
| 59 | * |
| 60 | * [29-Apr-1998 C. Scott Ananian] Updated above description of symlink |
| 61 | * resolution to correspond with current state of the code. |
| 62 | * |
| 63 | * Note that the symlink resolution is not *completely* iterative. |
| 64 | * There is still a significant amount of tail- and mid- recursion in |
| 65 | * the algorithm. Also, note that <fs>_readlink() is not used in |
| 66 | * lookup_dentry(): lookup_dentry() on the result of <fs>_readlink() |
| 67 | * may return different results than <fs>_follow_link(). Many virtual |
| 68 | * filesystems (including /proc) exhibit this behavior. |
| 69 | */ |
| 70 | |
| 71 | /* [24-Feb-97 T. Schoebel-Theuer] Side effects caused by new implementation: |
| 72 | * New symlink semantics: when open() is called with flags O_CREAT | O_EXCL |
| 73 | * and the name already exists in form of a symlink, try to create the new |
| 74 | * name indicated by the symlink. The old code always complained that the |
| 75 | * name already exists, due to not following the symlink even if its target |
| 76 | * is nonexistent. The new semantics affects also mknod() and link() when |
Lucas De Marchi | 25985ed | 2011-03-30 22:57:33 -0300 | [diff] [blame] | 77 | * the name is a symlink pointing to a non-existent name. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 78 | * |
| 79 | * I don't know which semantics is the right one, since I have no access |
| 80 | * to standards. But I found by trial that HP-UX 9.0 has the full "new" |
| 81 | * semantics implemented, while SunOS 4.1.1 and Solaris (SunOS 5.4) have the |
| 82 | * "old" one. Personally, I think the new semantics is much more logical. |
| 83 | * Note that "ln old new" where "new" is a symlink pointing to a non-existing |
| 84 | * file does succeed in both HP-UX and SunOs, but not in Solaris |
| 85 | * and in the old Linux semantics. |
| 86 | */ |
| 87 | |
| 88 | /* [16-Dec-97 Kevin Buhr] For security reasons, we change some symlink |
| 89 | * semantics. See the comments in "open_namei" and "do_link" below. |
| 90 | * |
| 91 | * [10-Sep-98 Alan Modra] Another symlink change. |
| 92 | */ |
| 93 | |
| 94 | /* [Feb-Apr 2000 AV] Complete rewrite. Rules for symlinks: |
| 95 | * inside the path - always follow. |
| 96 | * in the last component in creation/removal/renaming - never follow. |
| 97 | * if LOOKUP_FOLLOW passed - follow. |
| 98 | * if the pathname has trailing slashes - follow. |
| 99 | * otherwise - don't follow. |
| 100 | * (applied in that order). |
| 101 | * |
| 102 | * [Jun 2000 AV] Inconsistent behaviour of open() in case if flags==O_CREAT |
| 103 | * restored for 2.4. This is the last surviving part of old 4.2BSD bug. |
| 104 | * During the 2.4 we need to fix the userland stuff depending on it - |
| 105 | * hopefully we will be able to get rid of that wart in 2.5. So far only |
| 106 | * XEmacs seems to be relying on it... |
| 107 | */ |
| 108 | /* |
| 109 | * [Sep 2001 AV] Single-semaphore locking scheme (kudos to David Holland) |
Arjan van de Ven | a11f3a0 | 2006-03-23 03:00:33 -0800 | [diff] [blame] | 110 | * implemented. Let's see if raised priority of ->s_vfs_rename_mutex gives |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 111 | * any extra contention... |
| 112 | */ |
| 113 | |
| 114 | /* In order to reduce some races, while at the same time doing additional |
| 115 | * checking and hopefully speeding things up, we copy filenames to the |
| 116 | * kernel data space before using them.. |
| 117 | * |
| 118 | * POSIX.1 2.4: an empty pathname is invalid (ENOENT). |
| 119 | * PATH_MAX includes the nul terminator --RR. |
| 120 | */ |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 121 | |
Al Viro | fd2f7cb | 2015-02-22 20:07:13 -0500 | [diff] [blame] | 122 | #define EMBEDDED_NAME_MAX (PATH_MAX - offsetof(struct filename, iname)) |
Jeff Layton | 7950e38 | 2012-10-10 16:43:13 -0400 | [diff] [blame] | 123 | |
David Drysdale | 51f39a1 | 2014-12-12 16:57:29 -0800 | [diff] [blame] | 124 | struct filename * |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 125 | getname_flags(const char __user *filename, int flags, int *empty) |
| 126 | { |
Al Viro | 94b5d26 | 2015-02-22 19:38:03 -0500 | [diff] [blame] | 127 | struct filename *result; |
Jeff Layton | 7950e38 | 2012-10-10 16:43:13 -0400 | [diff] [blame] | 128 | char *kname; |
Al Viro | 94b5d26 | 2015-02-22 19:38:03 -0500 | [diff] [blame] | 129 | int len; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 130 | |
Jeff Layton | 7ac8626 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 131 | result = audit_reusename(filename); |
| 132 | if (result) |
| 133 | return result; |
| 134 | |
Jeff Layton | 7950e38 | 2012-10-10 16:43:13 -0400 | [diff] [blame] | 135 | result = __getname(); |
Linus Torvalds | 3f9f0aa | 2012-04-28 14:38:32 -0700 | [diff] [blame] | 136 | if (unlikely(!result)) |
Eric Paris | 4043cde | 2012-01-03 14:23:08 -0500 | [diff] [blame] | 137 | return ERR_PTR(-ENOMEM); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 138 | |
Jeff Layton | 7950e38 | 2012-10-10 16:43:13 -0400 | [diff] [blame] | 139 | /* |
| 140 | * First, try to embed the struct filename inside the names_cache |
| 141 | * allocation |
| 142 | */ |
Al Viro | fd2f7cb | 2015-02-22 20:07:13 -0500 | [diff] [blame] | 143 | kname = (char *)result->iname; |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 144 | result->name = kname; |
Jeff Layton | 7950e38 | 2012-10-10 16:43:13 -0400 | [diff] [blame] | 145 | |
Al Viro | 94b5d26 | 2015-02-22 19:38:03 -0500 | [diff] [blame] | 146 | len = strncpy_from_user(kname, filename, EMBEDDED_NAME_MAX); |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 147 | if (unlikely(len < 0)) { |
Al Viro | 94b5d26 | 2015-02-22 19:38:03 -0500 | [diff] [blame] | 148 | __putname(result); |
| 149 | return ERR_PTR(len); |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 150 | } |
Linus Torvalds | 3f9f0aa | 2012-04-28 14:38:32 -0700 | [diff] [blame] | 151 | |
Jeff Layton | 7950e38 | 2012-10-10 16:43:13 -0400 | [diff] [blame] | 152 | /* |
| 153 | * Uh-oh. We have a name that's approaching PATH_MAX. Allocate a |
| 154 | * separate struct filename so we can dedicate the entire |
| 155 | * names_cache allocation for the pathname, and re-do the copy from |
| 156 | * userland. |
| 157 | */ |
Al Viro | 94b5d26 | 2015-02-22 19:38:03 -0500 | [diff] [blame] | 158 | if (unlikely(len == EMBEDDED_NAME_MAX)) { |
Al Viro | fd2f7cb | 2015-02-22 20:07:13 -0500 | [diff] [blame] | 159 | const size_t size = offsetof(struct filename, iname[1]); |
Jeff Layton | 7950e38 | 2012-10-10 16:43:13 -0400 | [diff] [blame] | 160 | kname = (char *)result; |
| 161 | |
Al Viro | fd2f7cb | 2015-02-22 20:07:13 -0500 | [diff] [blame] | 162 | /* |
| 163 | * size is chosen that way we to guarantee that |
| 164 | * result->iname[0] is within the same object and that |
| 165 | * kname can't be equal to result->iname, no matter what. |
| 166 | */ |
| 167 | result = kzalloc(size, GFP_KERNEL); |
Al Viro | 94b5d26 | 2015-02-22 19:38:03 -0500 | [diff] [blame] | 168 | if (unlikely(!result)) { |
| 169 | __putname(kname); |
| 170 | return ERR_PTR(-ENOMEM); |
Jeff Layton | 7950e38 | 2012-10-10 16:43:13 -0400 | [diff] [blame] | 171 | } |
| 172 | result->name = kname; |
Al Viro | 94b5d26 | 2015-02-22 19:38:03 -0500 | [diff] [blame] | 173 | len = strncpy_from_user(kname, filename, PATH_MAX); |
| 174 | if (unlikely(len < 0)) { |
| 175 | __putname(kname); |
| 176 | kfree(result); |
| 177 | return ERR_PTR(len); |
| 178 | } |
| 179 | if (unlikely(len == PATH_MAX)) { |
| 180 | __putname(kname); |
| 181 | kfree(result); |
| 182 | return ERR_PTR(-ENAMETOOLONG); |
| 183 | } |
Jeff Layton | 7950e38 | 2012-10-10 16:43:13 -0400 | [diff] [blame] | 184 | } |
| 185 | |
Al Viro | 94b5d26 | 2015-02-22 19:38:03 -0500 | [diff] [blame] | 186 | result->refcnt = 1; |
Linus Torvalds | 3f9f0aa | 2012-04-28 14:38:32 -0700 | [diff] [blame] | 187 | /* The empty path is special. */ |
| 188 | if (unlikely(!len)) { |
| 189 | if (empty) |
Eric Paris | 4043cde | 2012-01-03 14:23:08 -0500 | [diff] [blame] | 190 | *empty = 1; |
Al Viro | 94b5d26 | 2015-02-22 19:38:03 -0500 | [diff] [blame] | 191 | if (!(flags & LOOKUP_EMPTY)) { |
| 192 | putname(result); |
| 193 | return ERR_PTR(-ENOENT); |
| 194 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 195 | } |
Linus Torvalds | 3f9f0aa | 2012-04-28 14:38:32 -0700 | [diff] [blame] | 196 | |
Jeff Layton | 7950e38 | 2012-10-10 16:43:13 -0400 | [diff] [blame] | 197 | result->uptr = filename; |
Linus Torvalds | c4ad8f9 | 2014-02-05 12:54:53 -0800 | [diff] [blame] | 198 | result->aname = NULL; |
Jeff Layton | 7950e38 | 2012-10-10 16:43:13 -0400 | [diff] [blame] | 199 | audit_getname(result); |
| 200 | return result; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 201 | } |
| 202 | |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 203 | struct filename * |
| 204 | getname(const char __user * filename) |
Al Viro | f52e0c1 | 2011-03-14 18:56:51 -0400 | [diff] [blame] | 205 | { |
Linus Torvalds | f7493e5 | 2012-03-22 16:10:40 -0700 | [diff] [blame] | 206 | return getname_flags(filename, 0, NULL); |
Al Viro | f52e0c1 | 2011-03-14 18:56:51 -0400 | [diff] [blame] | 207 | } |
| 208 | |
Linus Torvalds | c4ad8f9 | 2014-02-05 12:54:53 -0800 | [diff] [blame] | 209 | struct filename * |
| 210 | getname_kernel(const char * filename) |
| 211 | { |
| 212 | struct filename *result; |
Paul Moore | 0851854 | 2015-01-21 23:59:56 -0500 | [diff] [blame] | 213 | int len = strlen(filename) + 1; |
Linus Torvalds | c4ad8f9 | 2014-02-05 12:54:53 -0800 | [diff] [blame] | 214 | |
| 215 | result = __getname(); |
| 216 | if (unlikely(!result)) |
| 217 | return ERR_PTR(-ENOMEM); |
| 218 | |
Paul Moore | 0851854 | 2015-01-21 23:59:56 -0500 | [diff] [blame] | 219 | if (len <= EMBEDDED_NAME_MAX) { |
Al Viro | fd2f7cb | 2015-02-22 20:07:13 -0500 | [diff] [blame] | 220 | result->name = (char *)result->iname; |
Paul Moore | 0851854 | 2015-01-21 23:59:56 -0500 | [diff] [blame] | 221 | } else if (len <= PATH_MAX) { |
| 222 | struct filename *tmp; |
| 223 | |
| 224 | tmp = kmalloc(sizeof(*tmp), GFP_KERNEL); |
| 225 | if (unlikely(!tmp)) { |
| 226 | __putname(result); |
| 227 | return ERR_PTR(-ENOMEM); |
| 228 | } |
| 229 | tmp->name = (char *)result; |
Paul Moore | 0851854 | 2015-01-21 23:59:56 -0500 | [diff] [blame] | 230 | result = tmp; |
| 231 | } else { |
| 232 | __putname(result); |
| 233 | return ERR_PTR(-ENAMETOOLONG); |
| 234 | } |
| 235 | memcpy((char *)result->name, filename, len); |
Linus Torvalds | c4ad8f9 | 2014-02-05 12:54:53 -0800 | [diff] [blame] | 236 | result->uptr = NULL; |
| 237 | result->aname = NULL; |
Paul Moore | 55422d0 | 2015-01-22 00:00:23 -0500 | [diff] [blame] | 238 | result->refcnt = 1; |
Paul Moore | fd3522f | 2015-01-22 00:00:10 -0500 | [diff] [blame] | 239 | audit_getname(result); |
Linus Torvalds | c4ad8f9 | 2014-02-05 12:54:53 -0800 | [diff] [blame] | 240 | |
Linus Torvalds | c4ad8f9 | 2014-02-05 12:54:53 -0800 | [diff] [blame] | 241 | return result; |
| 242 | } |
| 243 | |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 244 | void putname(struct filename *name) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 245 | { |
Paul Moore | 55422d0 | 2015-01-22 00:00:23 -0500 | [diff] [blame] | 246 | BUG_ON(name->refcnt <= 0); |
| 247 | |
| 248 | if (--name->refcnt > 0) |
| 249 | return; |
| 250 | |
Al Viro | fd2f7cb | 2015-02-22 20:07:13 -0500 | [diff] [blame] | 251 | if (name->name != name->iname) { |
Paul Moore | 55422d0 | 2015-01-22 00:00:23 -0500 | [diff] [blame] | 252 | __putname(name->name); |
| 253 | kfree(name); |
| 254 | } else |
| 255 | __putname(name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 256 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 257 | |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 258 | static int check_acl(struct inode *inode, int mask) |
| 259 | { |
Linus Torvalds | 84635d6 | 2011-07-25 22:47:03 -0700 | [diff] [blame] | 260 | #ifdef CONFIG_FS_POSIX_ACL |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 261 | struct posix_acl *acl; |
| 262 | |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 263 | if (mask & MAY_NOT_BLOCK) { |
Al Viro | 3567866 | 2011-08-02 21:32:13 -0400 | [diff] [blame] | 264 | acl = get_cached_acl_rcu(inode, ACL_TYPE_ACCESS); |
| 265 | if (!acl) |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 266 | return -EAGAIN; |
Al Viro | 3567866 | 2011-08-02 21:32:13 -0400 | [diff] [blame] | 267 | /* no ->get_acl() calls in RCU mode... */ |
| 268 | if (acl == ACL_NOT_CACHED) |
| 269 | return -ECHILD; |
Ari Savolainen | 206b1d0 | 2011-08-06 19:43:07 +0300 | [diff] [blame] | 270 | return posix_acl_permission(inode, acl, mask & ~MAY_NOT_BLOCK); |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 271 | } |
| 272 | |
Christoph Hellwig | 2982baa | 2013-12-20 05:16:38 -0800 | [diff] [blame] | 273 | acl = get_acl(inode, ACL_TYPE_ACCESS); |
| 274 | if (IS_ERR(acl)) |
| 275 | return PTR_ERR(acl); |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 276 | if (acl) { |
| 277 | int error = posix_acl_permission(inode, acl, mask); |
| 278 | posix_acl_release(acl); |
| 279 | return error; |
| 280 | } |
Linus Torvalds | 84635d6 | 2011-07-25 22:47:03 -0700 | [diff] [blame] | 281 | #endif |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 282 | |
| 283 | return -EAGAIN; |
| 284 | } |
| 285 | |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 286 | /* |
Andreas Gruenbacher | 948409c | 2011-10-23 23:13:33 +0530 | [diff] [blame] | 287 | * This does the basic permission checking |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 288 | */ |
Al Viro | 7e40145 | 2011-06-20 19:12:17 -0400 | [diff] [blame] | 289 | static int acl_permission_check(struct inode *inode, int mask) |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 290 | { |
Linus Torvalds | 26cf46b | 2011-05-13 11:51:01 -0700 | [diff] [blame] | 291 | unsigned int mode = inode->i_mode; |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 292 | |
Eric W. Biederman | 8e96e3b | 2012-03-03 21:17:15 -0800 | [diff] [blame] | 293 | if (likely(uid_eq(current_fsuid(), inode->i_uid))) |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 294 | mode >>= 6; |
| 295 | else { |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 296 | if (IS_POSIXACL(inode) && (mode & S_IRWXG)) { |
Al Viro | 7e40145 | 2011-06-20 19:12:17 -0400 | [diff] [blame] | 297 | int error = check_acl(inode, mask); |
Nick Piggin | b74c79e | 2011-01-07 17:49:58 +1100 | [diff] [blame] | 298 | if (error != -EAGAIN) |
| 299 | return error; |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 300 | } |
| 301 | |
| 302 | if (in_group_p(inode->i_gid)) |
| 303 | mode >>= 3; |
| 304 | } |
| 305 | |
| 306 | /* |
| 307 | * If the DACs are ok we don't need any capability check. |
| 308 | */ |
Al Viro | 9c2c703 | 2011-06-20 19:06:22 -0400 | [diff] [blame] | 309 | if ((mask & ~mode & (MAY_READ | MAY_WRITE | MAY_EXEC)) == 0) |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 310 | return 0; |
| 311 | return -EACCES; |
| 312 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 313 | |
| 314 | /** |
Nick Piggin | b74c79e | 2011-01-07 17:49:58 +1100 | [diff] [blame] | 315 | * generic_permission - check for access rights on a Posix-like filesystem |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 316 | * @inode: inode to check access rights for |
Andreas Gruenbacher | 8fd90c8 | 2011-10-23 23:13:30 +0530 | [diff] [blame] | 317 | * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC, ...) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 318 | * |
| 319 | * Used to check for read/write/execute permissions on a file. |
| 320 | * We use "fsuid" for this, letting us set arbitrary permissions |
| 321 | * for filesystem access without changing the "normal" uids which |
Nick Piggin | b74c79e | 2011-01-07 17:49:58 +1100 | [diff] [blame] | 322 | * are used for other things. |
| 323 | * |
| 324 | * generic_permission is rcu-walk aware. It returns -ECHILD in case an rcu-walk |
| 325 | * request cannot be satisfied (eg. requires blocking or too much complexity). |
| 326 | * It would then be called again in ref-walk mode. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 327 | */ |
Al Viro | 2830ba7 | 2011-06-20 19:16:29 -0400 | [diff] [blame] | 328 | int generic_permission(struct inode *inode, int mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 329 | { |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 330 | int ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 331 | |
| 332 | /* |
Andreas Gruenbacher | 948409c | 2011-10-23 23:13:33 +0530 | [diff] [blame] | 333 | * Do the basic permission checks. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 334 | */ |
Al Viro | 7e40145 | 2011-06-20 19:12:17 -0400 | [diff] [blame] | 335 | ret = acl_permission_check(inode, mask); |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 336 | if (ret != -EACCES) |
| 337 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 338 | |
Al Viro | d594e7e | 2011-06-20 19:55:42 -0400 | [diff] [blame] | 339 | if (S_ISDIR(inode->i_mode)) { |
| 340 | /* DACs are overridable for directories */ |
Andy Lutomirski | 23adbe1 | 2014-06-10 12:45:42 -0700 | [diff] [blame] | 341 | if (capable_wrt_inode_uidgid(inode, CAP_DAC_OVERRIDE)) |
Al Viro | d594e7e | 2011-06-20 19:55:42 -0400 | [diff] [blame] | 342 | return 0; |
| 343 | if (!(mask & MAY_WRITE)) |
Andy Lutomirski | 23adbe1 | 2014-06-10 12:45:42 -0700 | [diff] [blame] | 344 | if (capable_wrt_inode_uidgid(inode, |
| 345 | CAP_DAC_READ_SEARCH)) |
Al Viro | d594e7e | 2011-06-20 19:55:42 -0400 | [diff] [blame] | 346 | return 0; |
| 347 | return -EACCES; |
| 348 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 349 | /* |
| 350 | * Read/write DACs are always overridable. |
Al Viro | d594e7e | 2011-06-20 19:55:42 -0400 | [diff] [blame] | 351 | * Executable DACs are overridable when there is |
| 352 | * at least one exec bit set. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 353 | */ |
Al Viro | d594e7e | 2011-06-20 19:55:42 -0400 | [diff] [blame] | 354 | if (!(mask & MAY_EXEC) || (inode->i_mode & S_IXUGO)) |
Andy Lutomirski | 23adbe1 | 2014-06-10 12:45:42 -0700 | [diff] [blame] | 355 | if (capable_wrt_inode_uidgid(inode, CAP_DAC_OVERRIDE)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 356 | return 0; |
| 357 | |
| 358 | /* |
| 359 | * Searching includes executable on directories, else just read. |
| 360 | */ |
Serge E. Hallyn | 7ea6600 | 2009-12-29 14:50:19 -0600 | [diff] [blame] | 361 | mask &= MAY_READ | MAY_WRITE | MAY_EXEC; |
Al Viro | d594e7e | 2011-06-20 19:55:42 -0400 | [diff] [blame] | 362 | if (mask == MAY_READ) |
Andy Lutomirski | 23adbe1 | 2014-06-10 12:45:42 -0700 | [diff] [blame] | 363 | if (capable_wrt_inode_uidgid(inode, CAP_DAC_READ_SEARCH)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 364 | return 0; |
| 365 | |
| 366 | return -EACCES; |
| 367 | } |
Al Viro | 4d35950 | 2014-03-14 12:20:17 -0400 | [diff] [blame] | 368 | EXPORT_SYMBOL(generic_permission); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 369 | |
Linus Torvalds | 3ddcd05 | 2011-08-06 22:45:50 -0700 | [diff] [blame] | 370 | /* |
| 371 | * We _really_ want to just do "generic_permission()" without |
| 372 | * even looking at the inode->i_op values. So we keep a cache |
| 373 | * flag in inode->i_opflags, that says "this has not special |
| 374 | * permission function, use the fast case". |
| 375 | */ |
| 376 | static inline int do_inode_permission(struct inode *inode, int mask) |
| 377 | { |
| 378 | if (unlikely(!(inode->i_opflags & IOP_FASTPERM))) { |
| 379 | if (likely(inode->i_op->permission)) |
| 380 | return inode->i_op->permission(inode, mask); |
| 381 | |
| 382 | /* This gets set once for the inode lifetime */ |
| 383 | spin_lock(&inode->i_lock); |
| 384 | inode->i_opflags |= IOP_FASTPERM; |
| 385 | spin_unlock(&inode->i_lock); |
| 386 | } |
| 387 | return generic_permission(inode, mask); |
| 388 | } |
| 389 | |
Christoph Hellwig | cb23beb | 2008-10-24 09:59:29 +0200 | [diff] [blame] | 390 | /** |
David Howells | 0bdaea9 | 2012-06-25 12:55:46 +0100 | [diff] [blame] | 391 | * __inode_permission - Check for access rights to a given inode |
| 392 | * @inode: Inode to check permission on |
| 393 | * @mask: Right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) |
Christoph Hellwig | cb23beb | 2008-10-24 09:59:29 +0200 | [diff] [blame] | 394 | * |
David Howells | 0bdaea9 | 2012-06-25 12:55:46 +0100 | [diff] [blame] | 395 | * Check for read/write/execute permissions on an inode. |
Andreas Gruenbacher | 948409c | 2011-10-23 23:13:33 +0530 | [diff] [blame] | 396 | * |
| 397 | * When checking for MAY_APPEND, MAY_WRITE must also be set in @mask. |
David Howells | 0bdaea9 | 2012-06-25 12:55:46 +0100 | [diff] [blame] | 398 | * |
| 399 | * This does not check for a read-only file system. You probably want |
| 400 | * inode_permission(). |
Christoph Hellwig | cb23beb | 2008-10-24 09:59:29 +0200 | [diff] [blame] | 401 | */ |
David Howells | 0bdaea9 | 2012-06-25 12:55:46 +0100 | [diff] [blame] | 402 | int __inode_permission(struct inode *inode, int mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 403 | { |
Al Viro | e6305c4 | 2008-07-15 21:03:57 -0400 | [diff] [blame] | 404 | int retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 405 | |
Linus Torvalds | 3ddcd05 | 2011-08-06 22:45:50 -0700 | [diff] [blame] | 406 | if (unlikely(mask & MAY_WRITE)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 407 | /* |
| 408 | * Nobody gets write access to an immutable file. |
| 409 | */ |
| 410 | if (IS_IMMUTABLE(inode)) |
| 411 | return -EACCES; |
| 412 | } |
| 413 | |
Linus Torvalds | 3ddcd05 | 2011-08-06 22:45:50 -0700 | [diff] [blame] | 414 | retval = do_inode_permission(inode, mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 415 | if (retval) |
| 416 | return retval; |
| 417 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 418 | retval = devcgroup_inode_permission(inode, mask); |
| 419 | if (retval) |
| 420 | return retval; |
| 421 | |
Eric Paris | d09ca73 | 2010-07-23 11:43:57 -0400 | [diff] [blame] | 422 | return security_inode_permission(inode, mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 423 | } |
Miklos Szeredi | bd5d085 | 2014-10-24 00:14:35 +0200 | [diff] [blame] | 424 | EXPORT_SYMBOL(__inode_permission); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 425 | |
Al Viro | f4d6ff8 | 2011-06-19 13:14:21 -0400 | [diff] [blame] | 426 | /** |
David Howells | 0bdaea9 | 2012-06-25 12:55:46 +0100 | [diff] [blame] | 427 | * sb_permission - Check superblock-level permissions |
| 428 | * @sb: Superblock of inode to check permission on |
Randy Dunlap | 5585263 | 2012-08-18 17:39:25 -0700 | [diff] [blame] | 429 | * @inode: Inode to check permission on |
David Howells | 0bdaea9 | 2012-06-25 12:55:46 +0100 | [diff] [blame] | 430 | * @mask: Right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) |
| 431 | * |
| 432 | * Separate out file-system wide checks from inode-specific permission checks. |
| 433 | */ |
| 434 | static int sb_permission(struct super_block *sb, struct inode *inode, int mask) |
| 435 | { |
| 436 | if (unlikely(mask & MAY_WRITE)) { |
| 437 | umode_t mode = inode->i_mode; |
| 438 | |
| 439 | /* Nobody gets write access to a read-only fs. */ |
| 440 | if ((sb->s_flags & MS_RDONLY) && |
| 441 | (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) |
| 442 | return -EROFS; |
| 443 | } |
| 444 | return 0; |
| 445 | } |
| 446 | |
| 447 | /** |
| 448 | * inode_permission - Check for access rights to a given inode |
| 449 | * @inode: Inode to check permission on |
| 450 | * @mask: Right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) |
| 451 | * |
| 452 | * Check for read/write/execute permissions on an inode. We use fs[ug]id for |
| 453 | * this, letting us set arbitrary permissions for filesystem access without |
| 454 | * changing the "normal" UIDs which are used for other things. |
| 455 | * |
| 456 | * When checking for MAY_APPEND, MAY_WRITE must also be set in @mask. |
| 457 | */ |
| 458 | int inode_permission(struct inode *inode, int mask) |
| 459 | { |
| 460 | int retval; |
| 461 | |
| 462 | retval = sb_permission(inode->i_sb, inode, mask); |
| 463 | if (retval) |
| 464 | return retval; |
| 465 | return __inode_permission(inode, mask); |
| 466 | } |
Al Viro | 4d35950 | 2014-03-14 12:20:17 -0400 | [diff] [blame] | 467 | EXPORT_SYMBOL(inode_permission); |
David Howells | 0bdaea9 | 2012-06-25 12:55:46 +0100 | [diff] [blame] | 468 | |
| 469 | /** |
Jan Blunck | 5dd784d0 | 2008-02-14 19:34:38 -0800 | [diff] [blame] | 470 | * path_get - get a reference to a path |
| 471 | * @path: path to get the reference to |
| 472 | * |
| 473 | * Given a path increment the reference count to the dentry and the vfsmount. |
| 474 | */ |
Al Viro | dcf787f | 2013-03-01 23:51:07 -0500 | [diff] [blame] | 475 | void path_get(const struct path *path) |
Jan Blunck | 5dd784d0 | 2008-02-14 19:34:38 -0800 | [diff] [blame] | 476 | { |
| 477 | mntget(path->mnt); |
| 478 | dget(path->dentry); |
| 479 | } |
| 480 | EXPORT_SYMBOL(path_get); |
| 481 | |
| 482 | /** |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 483 | * path_put - put a reference to a path |
| 484 | * @path: path to put the reference to |
| 485 | * |
| 486 | * Given a path decrement the reference count to the dentry and the vfsmount. |
| 487 | */ |
Al Viro | dcf787f | 2013-03-01 23:51:07 -0500 | [diff] [blame] | 488 | void path_put(const struct path *path) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 489 | { |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 490 | dput(path->dentry); |
| 491 | mntput(path->mnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 492 | } |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 493 | EXPORT_SYMBOL(path_put); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 494 | |
Al Viro | 894bc8c | 2015-05-02 07:16:16 -0400 | [diff] [blame] | 495 | #define EMBEDDED_LEVELS 2 |
Al Viro | 1f55a6e | 2014-11-01 19:30:41 -0400 | [diff] [blame] | 496 | struct nameidata { |
| 497 | struct path path; |
Al Viro | 1cf2665 | 2015-05-06 16:01:56 -0400 | [diff] [blame] | 498 | struct qstr last; |
Al Viro | 1f55a6e | 2014-11-01 19:30:41 -0400 | [diff] [blame] | 499 | struct path root; |
| 500 | struct inode *inode; /* path.dentry.d_inode */ |
| 501 | unsigned int flags; |
Al Viro | 9883d18 | 2015-05-13 07:28:08 -0400 | [diff] [blame] | 502 | unsigned seq, m_seq; |
Al Viro | 1f55a6e | 2014-11-01 19:30:41 -0400 | [diff] [blame] | 503 | int last_type; |
| 504 | unsigned depth; |
NeilBrown | 756daf2 | 2015-03-23 13:37:38 +1100 | [diff] [blame] | 505 | int total_link_count; |
Al Viro | 697fc6c | 2015-05-02 19:38:35 -0400 | [diff] [blame] | 506 | struct saved { |
| 507 | struct path link; |
| 508 | void *cookie; |
| 509 | const char *name; |
Al Viro | 237d8b3 | 2015-05-07 09:21:14 -0400 | [diff] [blame] | 510 | struct inode *inode; |
Al Viro | 0450b2d | 2015-05-08 13:23:53 -0400 | [diff] [blame] | 511 | unsigned seq; |
Al Viro | 894bc8c | 2015-05-02 07:16:16 -0400 | [diff] [blame] | 512 | } *stack, internal[EMBEDDED_LEVELS]; |
Al Viro | 9883d18 | 2015-05-13 07:28:08 -0400 | [diff] [blame] | 513 | struct filename *name; |
| 514 | struct nameidata *saved; |
| 515 | unsigned root_seq; |
| 516 | int dfd; |
Al Viro | 1f55a6e | 2014-11-01 19:30:41 -0400 | [diff] [blame] | 517 | }; |
| 518 | |
Al Viro | 9883d18 | 2015-05-13 07:28:08 -0400 | [diff] [blame] | 519 | static void set_nameidata(struct nameidata *p, int dfd, struct filename *name) |
Al Viro | 894bc8c | 2015-05-02 07:16:16 -0400 | [diff] [blame] | 520 | { |
NeilBrown | 756daf2 | 2015-03-23 13:37:38 +1100 | [diff] [blame] | 521 | struct nameidata *old = current->nameidata; |
| 522 | p->stack = p->internal; |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 523 | p->dfd = dfd; |
| 524 | p->name = name; |
NeilBrown | 756daf2 | 2015-03-23 13:37:38 +1100 | [diff] [blame] | 525 | p->total_link_count = old ? old->total_link_count : 0; |
Al Viro | 9883d18 | 2015-05-13 07:28:08 -0400 | [diff] [blame] | 526 | p->saved = old; |
NeilBrown | 756daf2 | 2015-03-23 13:37:38 +1100 | [diff] [blame] | 527 | current->nameidata = p; |
Al Viro | 894bc8c | 2015-05-02 07:16:16 -0400 | [diff] [blame] | 528 | } |
| 529 | |
Al Viro | 9883d18 | 2015-05-13 07:28:08 -0400 | [diff] [blame] | 530 | static void restore_nameidata(void) |
Al Viro | 894bc8c | 2015-05-02 07:16:16 -0400 | [diff] [blame] | 531 | { |
Al Viro | 9883d18 | 2015-05-13 07:28:08 -0400 | [diff] [blame] | 532 | struct nameidata *now = current->nameidata, *old = now->saved; |
NeilBrown | 756daf2 | 2015-03-23 13:37:38 +1100 | [diff] [blame] | 533 | |
| 534 | current->nameidata = old; |
| 535 | if (old) |
| 536 | old->total_link_count = now->total_link_count; |
| 537 | if (now->stack != now->internal) { |
| 538 | kfree(now->stack); |
| 539 | now->stack = now->internal; |
Al Viro | 894bc8c | 2015-05-02 07:16:16 -0400 | [diff] [blame] | 540 | } |
| 541 | } |
| 542 | |
| 543 | static int __nd_alloc_stack(struct nameidata *nd) |
| 544 | { |
Al Viro | bc40aee | 2015-05-09 13:04:24 -0400 | [diff] [blame] | 545 | struct saved *p; |
| 546 | |
| 547 | if (nd->flags & LOOKUP_RCU) { |
| 548 | p= kmalloc(MAXSYMLINKS * sizeof(struct saved), |
| 549 | GFP_ATOMIC); |
| 550 | if (unlikely(!p)) |
| 551 | return -ECHILD; |
| 552 | } else { |
| 553 | p= kmalloc(MAXSYMLINKS * sizeof(struct saved), |
Al Viro | 894bc8c | 2015-05-02 07:16:16 -0400 | [diff] [blame] | 554 | GFP_KERNEL); |
Al Viro | bc40aee | 2015-05-09 13:04:24 -0400 | [diff] [blame] | 555 | if (unlikely(!p)) |
| 556 | return -ENOMEM; |
| 557 | } |
Al Viro | 894bc8c | 2015-05-02 07:16:16 -0400 | [diff] [blame] | 558 | memcpy(p, nd->internal, sizeof(nd->internal)); |
| 559 | nd->stack = p; |
| 560 | return 0; |
| 561 | } |
| 562 | |
Eric W. Biederman | 397d425 | 2015-08-15 20:27:13 -0500 | [diff] [blame] | 563 | /** |
| 564 | * path_connected - Verify that a path->dentry is below path->mnt.mnt_root |
| 565 | * @path: nameidate to verify |
| 566 | * |
| 567 | * Rename can sometimes move a file or directory outside of a bind |
| 568 | * mount, path_connected allows those cases to be detected. |
| 569 | */ |
| 570 | static bool path_connected(const struct path *path) |
| 571 | { |
| 572 | struct vfsmount *mnt = path->mnt; |
| 573 | |
| 574 | /* Only bind mounts can have disconnected paths */ |
| 575 | if (mnt->mnt_root == mnt->mnt_sb->s_root) |
| 576 | return true; |
| 577 | |
| 578 | return is_subdir(path->dentry, mnt->mnt_root); |
| 579 | } |
| 580 | |
Al Viro | 894bc8c | 2015-05-02 07:16:16 -0400 | [diff] [blame] | 581 | static inline int nd_alloc_stack(struct nameidata *nd) |
| 582 | { |
Al Viro | da4e0be | 2015-05-03 20:52:15 -0400 | [diff] [blame] | 583 | if (likely(nd->depth != EMBEDDED_LEVELS)) |
Al Viro | 894bc8c | 2015-05-02 07:16:16 -0400 | [diff] [blame] | 584 | return 0; |
| 585 | if (likely(nd->stack != nd->internal)) |
| 586 | return 0; |
| 587 | return __nd_alloc_stack(nd); |
| 588 | } |
| 589 | |
Al Viro | 7973387 | 2015-05-09 12:55:43 -0400 | [diff] [blame] | 590 | static void drop_links(struct nameidata *nd) |
| 591 | { |
| 592 | int i = nd->depth; |
| 593 | while (i--) { |
| 594 | struct saved *last = nd->stack + i; |
| 595 | struct inode *inode = last->inode; |
| 596 | if (last->cookie && inode->i_op->put_link) { |
| 597 | inode->i_op->put_link(inode, last->cookie); |
| 598 | last->cookie = NULL; |
| 599 | } |
| 600 | } |
| 601 | } |
| 602 | |
| 603 | static void terminate_walk(struct nameidata *nd) |
| 604 | { |
| 605 | drop_links(nd); |
| 606 | if (!(nd->flags & LOOKUP_RCU)) { |
| 607 | int i; |
| 608 | path_put(&nd->path); |
| 609 | for (i = 0; i < nd->depth; i++) |
| 610 | path_put(&nd->stack[i].link); |
Al Viro | 102b8af | 2015-05-12 17:35:52 -0400 | [diff] [blame] | 611 | if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT)) { |
| 612 | path_put(&nd->root); |
| 613 | nd->root.mnt = NULL; |
| 614 | } |
Al Viro | 7973387 | 2015-05-09 12:55:43 -0400 | [diff] [blame] | 615 | } else { |
| 616 | nd->flags &= ~LOOKUP_RCU; |
| 617 | if (!(nd->flags & LOOKUP_ROOT)) |
| 618 | nd->root.mnt = NULL; |
| 619 | rcu_read_unlock(); |
| 620 | } |
| 621 | nd->depth = 0; |
| 622 | } |
| 623 | |
| 624 | /* path_put is needed afterwards regardless of success or failure */ |
| 625 | static bool legitimize_path(struct nameidata *nd, |
| 626 | struct path *path, unsigned seq) |
| 627 | { |
| 628 | int res = __legitimize_mnt(path->mnt, nd->m_seq); |
| 629 | if (unlikely(res)) { |
| 630 | if (res > 0) |
| 631 | path->mnt = NULL; |
| 632 | path->dentry = NULL; |
| 633 | return false; |
| 634 | } |
| 635 | if (unlikely(!lockref_get_not_dead(&path->dentry->d_lockref))) { |
| 636 | path->dentry = NULL; |
| 637 | return false; |
| 638 | } |
| 639 | return !read_seqcount_retry(&path->dentry->d_seq, seq); |
| 640 | } |
| 641 | |
| 642 | static bool legitimize_links(struct nameidata *nd) |
| 643 | { |
| 644 | int i; |
| 645 | for (i = 0; i < nd->depth; i++) { |
| 646 | struct saved *last = nd->stack + i; |
| 647 | if (unlikely(!legitimize_path(nd, &last->link, last->seq))) { |
| 648 | drop_links(nd); |
| 649 | nd->depth = i + 1; |
| 650 | return false; |
| 651 | } |
| 652 | } |
| 653 | return true; |
| 654 | } |
| 655 | |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 656 | /* |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 657 | * Path walking has 2 modes, rcu-walk and ref-walk (see |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 658 | * Documentation/filesystems/path-lookup.txt). In situations when we can't |
| 659 | * continue in RCU mode, we attempt to drop out of rcu-walk mode and grab |
| 660 | * normal reference counts on dentries and vfsmounts to transition to rcu-walk |
| 661 | * mode. Refcounts are grabbed at the last known good point before rcu-walk |
| 662 | * got stuck, so ref-walk may continue from there. If this is not successful |
| 663 | * (eg. a seqcount has changed), then failure is returned and it's up to caller |
| 664 | * to restart the path walk from the beginning in ref-walk mode. |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 665 | */ |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 666 | |
| 667 | /** |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 668 | * unlazy_walk - try to switch to ref-walk mode. |
| 669 | * @nd: nameidata pathwalk data |
| 670 | * @dentry: child of nd->path.dentry or NULL |
Al Viro | 6e9918b | 2015-05-05 09:26:05 -0400 | [diff] [blame] | 671 | * @seq: seq number to check dentry against |
Randy Dunlap | 3919162 | 2011-01-08 19:36:21 -0800 | [diff] [blame] | 672 | * Returns: 0 on success, -ECHILD on failure |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 673 | * |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 674 | * unlazy_walk attempts to legitimize the current nd->path, nd->root and dentry |
| 675 | * for ref-walk mode. @dentry must be a path found by a do_lookup call on |
| 676 | * @nd or NULL. Must be called from rcu-walk context. |
Al Viro | 7973387 | 2015-05-09 12:55:43 -0400 | [diff] [blame] | 677 | * Nothing should touch nameidata between unlazy_walk() failure and |
| 678 | * terminate_walk(). |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 679 | */ |
Al Viro | 6e9918b | 2015-05-05 09:26:05 -0400 | [diff] [blame] | 680 | static int unlazy_walk(struct nameidata *nd, struct dentry *dentry, unsigned seq) |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 681 | { |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 682 | struct dentry *parent = nd->path.dentry; |
| 683 | |
| 684 | BUG_ON(!(nd->flags & LOOKUP_RCU)); |
Linus Torvalds | e5c832d | 2013-09-08 18:13:49 -0700 | [diff] [blame] | 685 | |
Linus Torvalds | e5c832d | 2013-09-08 18:13:49 -0700 | [diff] [blame] | 686 | nd->flags &= ~LOOKUP_RCU; |
Al Viro | 7973387 | 2015-05-09 12:55:43 -0400 | [diff] [blame] | 687 | if (unlikely(!legitimize_links(nd))) |
| 688 | goto out2; |
| 689 | if (unlikely(!legitimize_mnt(nd->path.mnt, nd->m_seq))) |
| 690 | goto out2; |
| 691 | if (unlikely(!lockref_get_not_dead(&parent->d_lockref))) |
| 692 | goto out1; |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 693 | |
Linus Torvalds | 1557008 | 2013-09-02 11:38:06 -0700 | [diff] [blame] | 694 | /* |
| 695 | * For a negative lookup, the lookup sequence point is the parents |
| 696 | * sequence point, and it only needs to revalidate the parent dentry. |
| 697 | * |
| 698 | * For a positive lookup, we need to move both the parent and the |
| 699 | * dentry from the RCU domain to be properly refcounted. And the |
| 700 | * sequence number in the dentry validates *both* dentry counters, |
| 701 | * since we checked the sequence number of the parent after we got |
| 702 | * the child sequence number. So we know the parent must still |
| 703 | * be valid if the child sequence number is still valid. |
| 704 | */ |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 705 | if (!dentry) { |
Linus Torvalds | e5c832d | 2013-09-08 18:13:49 -0700 | [diff] [blame] | 706 | if (read_seqcount_retry(&parent->d_seq, nd->seq)) |
| 707 | goto out; |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 708 | BUG_ON(nd->inode != parent->d_inode); |
| 709 | } else { |
Linus Torvalds | e5c832d | 2013-09-08 18:13:49 -0700 | [diff] [blame] | 710 | if (!lockref_get_not_dead(&dentry->d_lockref)) |
| 711 | goto out; |
Al Viro | 6e9918b | 2015-05-05 09:26:05 -0400 | [diff] [blame] | 712 | if (read_seqcount_retry(&dentry->d_seq, seq)) |
Linus Torvalds | e5c832d | 2013-09-08 18:13:49 -0700 | [diff] [blame] | 713 | goto drop_dentry; |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 714 | } |
Linus Torvalds | e5c832d | 2013-09-08 18:13:49 -0700 | [diff] [blame] | 715 | |
| 716 | /* |
| 717 | * Sequence counts matched. Now make sure that the root is |
| 718 | * still valid and get it if required. |
| 719 | */ |
| 720 | if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT)) { |
Al Viro | 5a8d87e | 2015-05-12 00:10:18 -0400 | [diff] [blame] | 721 | if (unlikely(!legitimize_path(nd, &nd->root, nd->root_seq))) { |
| 722 | rcu_read_unlock(); |
| 723 | dput(dentry); |
| 724 | return -ECHILD; |
Al Viro | 7973387 | 2015-05-09 12:55:43 -0400 | [diff] [blame] | 725 | } |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 726 | } |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 727 | |
Al Viro | 8b61e74 | 2013-11-08 12:45:01 -0500 | [diff] [blame] | 728 | rcu_read_unlock(); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 729 | return 0; |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 730 | |
Linus Torvalds | e5c832d | 2013-09-08 18:13:49 -0700 | [diff] [blame] | 731 | drop_dentry: |
Al Viro | 8b61e74 | 2013-11-08 12:45:01 -0500 | [diff] [blame] | 732 | rcu_read_unlock(); |
Linus Torvalds | 1557008 | 2013-09-02 11:38:06 -0700 | [diff] [blame] | 733 | dput(dentry); |
Linus Torvalds | d0d2727 | 2013-09-10 12:17:49 -0700 | [diff] [blame] | 734 | goto drop_root_mnt; |
Al Viro | 7973387 | 2015-05-09 12:55:43 -0400 | [diff] [blame] | 735 | out2: |
| 736 | nd->path.mnt = NULL; |
| 737 | out1: |
| 738 | nd->path.dentry = NULL; |
Linus Torvalds | e5c832d | 2013-09-08 18:13:49 -0700 | [diff] [blame] | 739 | out: |
Al Viro | 8b61e74 | 2013-11-08 12:45:01 -0500 | [diff] [blame] | 740 | rcu_read_unlock(); |
Linus Torvalds | d0d2727 | 2013-09-10 12:17:49 -0700 | [diff] [blame] | 741 | drop_root_mnt: |
| 742 | if (!(nd->flags & LOOKUP_ROOT)) |
| 743 | nd->root.mnt = NULL; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 744 | return -ECHILD; |
| 745 | } |
| 746 | |
Al Viro | 7973387 | 2015-05-09 12:55:43 -0400 | [diff] [blame] | 747 | static int unlazy_link(struct nameidata *nd, struct path *link, unsigned seq) |
| 748 | { |
| 749 | if (unlikely(!legitimize_path(nd, link, seq))) { |
| 750 | drop_links(nd); |
| 751 | nd->depth = 0; |
| 752 | nd->flags &= ~LOOKUP_RCU; |
| 753 | nd->path.mnt = NULL; |
| 754 | nd->path.dentry = NULL; |
| 755 | if (!(nd->flags & LOOKUP_ROOT)) |
| 756 | nd->root.mnt = NULL; |
| 757 | rcu_read_unlock(); |
| 758 | } else if (likely(unlazy_walk(nd, NULL, 0)) == 0) { |
| 759 | return 0; |
| 760 | } |
| 761 | path_put(link); |
| 762 | return -ECHILD; |
| 763 | } |
| 764 | |
Al Viro | 4ce16ef3 | 2012-06-10 16:10:59 -0400 | [diff] [blame] | 765 | static inline int d_revalidate(struct dentry *dentry, unsigned int flags) |
Nick Piggin | 34286d6 | 2011-01-07 17:49:57 +1100 | [diff] [blame] | 766 | { |
Al Viro | 4ce16ef3 | 2012-06-10 16:10:59 -0400 | [diff] [blame] | 767 | return dentry->d_op->d_revalidate(dentry, flags); |
Nick Piggin | 34286d6 | 2011-01-07 17:49:57 +1100 | [diff] [blame] | 768 | } |
| 769 | |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 770 | /** |
| 771 | * complete_walk - successful completion of path walk |
| 772 | * @nd: pointer nameidata |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 773 | * |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 774 | * If we had been in RCU mode, drop out of it and legitimize nd->path. |
| 775 | * Revalidate the final result, unless we'd already done that during |
| 776 | * the path walk or the filesystem doesn't ask for it. Return 0 on |
| 777 | * success, -error on failure. In case of failure caller does not |
| 778 | * need to drop nd->path. |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 779 | */ |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 780 | static int complete_walk(struct nameidata *nd) |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 781 | { |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 782 | struct dentry *dentry = nd->path.dentry; |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 783 | int status; |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 784 | |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 785 | if (nd->flags & LOOKUP_RCU) { |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 786 | if (!(nd->flags & LOOKUP_ROOT)) |
| 787 | nd->root.mnt = NULL; |
Al Viro | 6e9918b | 2015-05-05 09:26:05 -0400 | [diff] [blame] | 788 | if (unlikely(unlazy_walk(nd, NULL, 0))) |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 789 | return -ECHILD; |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 790 | } |
| 791 | |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 792 | if (likely(!(nd->flags & LOOKUP_JUMPED))) |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 793 | return 0; |
| 794 | |
Jeff Layton | ecf3d1f | 2013-02-20 11:19:05 -0500 | [diff] [blame] | 795 | if (likely(!(dentry->d_flags & DCACHE_OP_WEAK_REVALIDATE))) |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 796 | return 0; |
| 797 | |
Jeff Layton | ecf3d1f | 2013-02-20 11:19:05 -0500 | [diff] [blame] | 798 | status = dentry->d_op->d_weak_revalidate(dentry, nd->flags); |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 799 | if (status > 0) |
| 800 | return 0; |
| 801 | |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 802 | if (!status) |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 803 | status = -ESTALE; |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 804 | |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 805 | return status; |
| 806 | } |
| 807 | |
Al Viro | 18d8c86 | 2015-05-12 16:32:34 -0400 | [diff] [blame] | 808 | static void set_root(struct nameidata *nd) |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 809 | { |
Al Viro | 7bd8837 | 2014-09-13 21:55:46 -0400 | [diff] [blame] | 810 | get_fs_root(current->fs, &nd->root); |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 811 | } |
| 812 | |
Al Viro | 06d7137 | 2015-06-29 12:07:04 -0400 | [diff] [blame] | 813 | static void set_root_rcu(struct nameidata *nd) |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 814 | { |
Al Viro | 7bd8837 | 2014-09-13 21:55:46 -0400 | [diff] [blame] | 815 | struct fs_struct *fs = current->fs; |
Al Viro | 8f47a016 | 2015-05-09 19:02:01 -0400 | [diff] [blame] | 816 | unsigned seq; |
Nick Piggin | c28cc36 | 2011-01-07 17:49:53 +1100 | [diff] [blame] | 817 | |
Al Viro | 7bd8837 | 2014-09-13 21:55:46 -0400 | [diff] [blame] | 818 | do { |
| 819 | seq = read_seqcount_begin(&fs->seq); |
| 820 | nd->root = fs->root; |
Al Viro | 8f47a016 | 2015-05-09 19:02:01 -0400 | [diff] [blame] | 821 | nd->root_seq = __read_seqcount_begin(&nd->root.dentry->d_seq); |
Al Viro | 7bd8837 | 2014-09-13 21:55:46 -0400 | [diff] [blame] | 822 | } while (read_seqcount_retry(&fs->seq, seq)); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 823 | } |
| 824 | |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 825 | static void path_put_conditional(struct path *path, struct nameidata *nd) |
Miklos Szeredi | 09dd17d | 2005-09-06 15:18:21 -0700 | [diff] [blame] | 826 | { |
| 827 | dput(path->dentry); |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 828 | if (path->mnt != nd->path.mnt) |
Miklos Szeredi | 09dd17d | 2005-09-06 15:18:21 -0700 | [diff] [blame] | 829 | mntput(path->mnt); |
| 830 | } |
| 831 | |
Nick Piggin | 7b9337a | 2011-01-14 08:42:43 +0000 | [diff] [blame] | 832 | static inline void path_to_nameidata(const struct path *path, |
| 833 | struct nameidata *nd) |
Miklos Szeredi | 09dd17d | 2005-09-06 15:18:21 -0700 | [diff] [blame] | 834 | { |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 835 | if (!(nd->flags & LOOKUP_RCU)) { |
| 836 | dput(nd->path.dentry); |
| 837 | if (nd->path.mnt != path->mnt) |
| 838 | mntput(nd->path.mnt); |
Huang Shijie | 9a22968 | 2010-04-02 17:37:13 +0800 | [diff] [blame] | 839 | } |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 840 | nd->path.mnt = path->mnt; |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 841 | nd->path.dentry = path->dentry; |
Miklos Szeredi | 09dd17d | 2005-09-06 15:18:21 -0700 | [diff] [blame] | 842 | } |
| 843 | |
Christoph Hellwig | b5fb63c1 | 2012-06-18 10:47:04 -0400 | [diff] [blame] | 844 | /* |
| 845 | * Helper to directly jump to a known parsed path from ->follow_link, |
| 846 | * caller must have taken a reference to path beforehand. |
| 847 | */ |
Al Viro | 6e77137 | 2015-05-02 13:37:52 -0400 | [diff] [blame] | 848 | void nd_jump_link(struct path *path) |
Christoph Hellwig | b5fb63c1 | 2012-06-18 10:47:04 -0400 | [diff] [blame] | 849 | { |
Al Viro | 6e77137 | 2015-05-02 13:37:52 -0400 | [diff] [blame] | 850 | struct nameidata *nd = current->nameidata; |
Christoph Hellwig | b5fb63c1 | 2012-06-18 10:47:04 -0400 | [diff] [blame] | 851 | path_put(&nd->path); |
| 852 | |
| 853 | nd->path = *path; |
| 854 | nd->inode = nd->path.dentry->d_inode; |
| 855 | nd->flags |= LOOKUP_JUMPED; |
Christoph Hellwig | b5fb63c1 | 2012-06-18 10:47:04 -0400 | [diff] [blame] | 856 | } |
| 857 | |
Al Viro | b9ff442 | 2015-05-02 20:19:23 -0400 | [diff] [blame] | 858 | static inline void put_link(struct nameidata *nd) |
Al Viro | 574197e | 2011-03-14 22:20:34 -0400 | [diff] [blame] | 859 | { |
Al Viro | 21c3003 | 2015-05-03 21:06:24 -0400 | [diff] [blame] | 860 | struct saved *last = nd->stack + --nd->depth; |
Al Viro | 237d8b3 | 2015-05-07 09:21:14 -0400 | [diff] [blame] | 861 | struct inode *inode = last->inode; |
Al Viro | b9ff442 | 2015-05-02 20:19:23 -0400 | [diff] [blame] | 862 | if (last->cookie && inode->i_op->put_link) |
Al Viro | 5f2c417 | 2015-05-07 11:14:26 -0400 | [diff] [blame] | 863 | inode->i_op->put_link(inode, last->cookie); |
Al Viro | 6548fae | 2015-05-07 20:32:22 -0400 | [diff] [blame] | 864 | if (!(nd->flags & LOOKUP_RCU)) |
| 865 | path_put(&last->link); |
Al Viro | 574197e | 2011-03-14 22:20:34 -0400 | [diff] [blame] | 866 | } |
| 867 | |
Linus Torvalds | 561ec64 | 2012-10-26 10:05:07 -0700 | [diff] [blame] | 868 | int sysctl_protected_symlinks __read_mostly = 0; |
| 869 | int sysctl_protected_hardlinks __read_mostly = 0; |
Kees Cook | 800179c | 2012-07-25 17:29:07 -0700 | [diff] [blame] | 870 | |
| 871 | /** |
| 872 | * may_follow_link - Check symlink following for unsafe situations |
Randy Dunlap | 5585263 | 2012-08-18 17:39:25 -0700 | [diff] [blame] | 873 | * @nd: nameidata pathwalk data |
Kees Cook | 800179c | 2012-07-25 17:29:07 -0700 | [diff] [blame] | 874 | * |
| 875 | * In the case of the sysctl_protected_symlinks sysctl being enabled, |
| 876 | * CAP_DAC_OVERRIDE needs to be specifically ignored if the symlink is |
| 877 | * in a sticky world-writable directory. This is to protect privileged |
| 878 | * processes from failing races against path names that may change out |
| 879 | * from under them by way of other users creating malicious symlinks. |
| 880 | * It will permit symlinks to be followed only when outside a sticky |
| 881 | * world-writable directory, or when the uid of the symlink and follower |
| 882 | * match, or when the directory owner matches the symlink's owner. |
| 883 | * |
| 884 | * Returns 0 if following the symlink is allowed, -ve on error. |
| 885 | */ |
Al Viro | fec2fa2 | 2015-05-06 15:58:18 -0400 | [diff] [blame] | 886 | static inline int may_follow_link(struct nameidata *nd) |
Kees Cook | 800179c | 2012-07-25 17:29:07 -0700 | [diff] [blame] | 887 | { |
| 888 | const struct inode *inode; |
| 889 | const struct inode *parent; |
| 890 | |
| 891 | if (!sysctl_protected_symlinks) |
| 892 | return 0; |
| 893 | |
| 894 | /* Allowed if owner and follower match. */ |
Al Viro | 237d8b3 | 2015-05-07 09:21:14 -0400 | [diff] [blame] | 895 | inode = nd->stack[0].inode; |
Eric W. Biederman | 81abe27 | 2012-08-03 09:38:08 -0700 | [diff] [blame] | 896 | if (uid_eq(current_cred()->fsuid, inode->i_uid)) |
Kees Cook | 800179c | 2012-07-25 17:29:07 -0700 | [diff] [blame] | 897 | return 0; |
| 898 | |
| 899 | /* Allowed if parent directory not sticky and world-writable. */ |
Al Viro | aa65fa3 | 2015-08-04 23:23:50 -0400 | [diff] [blame] | 900 | parent = nd->inode; |
Kees Cook | 800179c | 2012-07-25 17:29:07 -0700 | [diff] [blame] | 901 | if ((parent->i_mode & (S_ISVTX|S_IWOTH)) != (S_ISVTX|S_IWOTH)) |
| 902 | return 0; |
| 903 | |
| 904 | /* Allowed if parent directory and link owner match. */ |
Eric W. Biederman | 81abe27 | 2012-08-03 09:38:08 -0700 | [diff] [blame] | 905 | if (uid_eq(parent->i_uid, inode->i_uid)) |
Kees Cook | 800179c | 2012-07-25 17:29:07 -0700 | [diff] [blame] | 906 | return 0; |
| 907 | |
Al Viro | 31956502 | 2015-05-07 20:37:40 -0400 | [diff] [blame] | 908 | if (nd->flags & LOOKUP_RCU) |
| 909 | return -ECHILD; |
| 910 | |
Al Viro | 1cf2665 | 2015-05-06 16:01:56 -0400 | [diff] [blame] | 911 | audit_log_link_denied("follow_link", &nd->stack[0].link); |
Kees Cook | 800179c | 2012-07-25 17:29:07 -0700 | [diff] [blame] | 912 | return -EACCES; |
| 913 | } |
| 914 | |
| 915 | /** |
| 916 | * safe_hardlink_source - Check for safe hardlink conditions |
| 917 | * @inode: the source inode to hardlink from |
| 918 | * |
| 919 | * Return false if at least one of the following conditions: |
| 920 | * - inode is not a regular file |
| 921 | * - inode is setuid |
| 922 | * - inode is setgid and group-exec |
| 923 | * - access failure for read and write |
| 924 | * |
| 925 | * Otherwise returns true. |
| 926 | */ |
| 927 | static bool safe_hardlink_source(struct inode *inode) |
| 928 | { |
| 929 | umode_t mode = inode->i_mode; |
| 930 | |
| 931 | /* Special files should not get pinned to the filesystem. */ |
| 932 | if (!S_ISREG(mode)) |
| 933 | return false; |
| 934 | |
| 935 | /* Setuid files should not get pinned to the filesystem. */ |
| 936 | if (mode & S_ISUID) |
| 937 | return false; |
| 938 | |
| 939 | /* Executable setgid files should not get pinned to the filesystem. */ |
| 940 | if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) |
| 941 | return false; |
| 942 | |
| 943 | /* Hardlinking to unreadable or unwritable sources is dangerous. */ |
| 944 | if (inode_permission(inode, MAY_READ | MAY_WRITE)) |
| 945 | return false; |
| 946 | |
| 947 | return true; |
| 948 | } |
| 949 | |
| 950 | /** |
| 951 | * may_linkat - Check permissions for creating a hardlink |
| 952 | * @link: the source to hardlink from |
| 953 | * |
| 954 | * Block hardlink when all of: |
| 955 | * - sysctl_protected_hardlinks enabled |
| 956 | * - fsuid does not match inode |
| 957 | * - hardlink source is unsafe (see safe_hardlink_source() above) |
Dirk Steinmetz | f2ca379 | 2015-10-20 16:09:19 +0200 | [diff] [blame] | 958 | * - not CAP_FOWNER in a namespace with the inode owner uid mapped |
Kees Cook | 800179c | 2012-07-25 17:29:07 -0700 | [diff] [blame] | 959 | * |
| 960 | * Returns 0 if successful, -ve on error. |
| 961 | */ |
| 962 | static int may_linkat(struct path *link) |
| 963 | { |
Kees Cook | 800179c | 2012-07-25 17:29:07 -0700 | [diff] [blame] | 964 | struct inode *inode; |
| 965 | |
| 966 | if (!sysctl_protected_hardlinks) |
| 967 | return 0; |
| 968 | |
Kees Cook | 800179c | 2012-07-25 17:29:07 -0700 | [diff] [blame] | 969 | inode = link->dentry->d_inode; |
| 970 | |
| 971 | /* Source inode owner (or CAP_FOWNER) can hardlink all they like, |
| 972 | * otherwise, it must be a safe source. |
| 973 | */ |
Dirk Steinmetz | f2ca379 | 2015-10-20 16:09:19 +0200 | [diff] [blame] | 974 | if (inode_owner_or_capable(inode) || safe_hardlink_source(inode)) |
Kees Cook | 800179c | 2012-07-25 17:29:07 -0700 | [diff] [blame] | 975 | return 0; |
| 976 | |
Kees Cook | a51d9ea | 2012-07-25 17:29:08 -0700 | [diff] [blame] | 977 | audit_log_link_denied("linkat", link); |
Kees Cook | 800179c | 2012-07-25 17:29:07 -0700 | [diff] [blame] | 978 | return -EPERM; |
| 979 | } |
| 980 | |
Al Viro | 3b2e7f7 | 2015-04-19 00:53:50 -0400 | [diff] [blame] | 981 | static __always_inline |
| 982 | const char *get_link(struct nameidata *nd) |
Ian Kent | 051d381 | 2006-03-27 01:14:53 -0800 | [diff] [blame] | 983 | { |
Al Viro | ab10492 | 2015-05-10 11:50:01 -0400 | [diff] [blame] | 984 | struct saved *last = nd->stack + nd->depth - 1; |
Al Viro | 1cf2665 | 2015-05-06 16:01:56 -0400 | [diff] [blame] | 985 | struct dentry *dentry = last->link.dentry; |
Al Viro | 237d8b3 | 2015-05-07 09:21:14 -0400 | [diff] [blame] | 986 | struct inode *inode = last->inode; |
Al Viro | 6d7b5aa | 2012-06-10 04:15:17 -0400 | [diff] [blame] | 987 | int error; |
Al Viro | 0a959df | 2015-04-18 18:23:41 -0400 | [diff] [blame] | 988 | const char *res; |
Ian Kent | 051d381 | 2006-03-27 01:14:53 -0800 | [diff] [blame] | 989 | |
NeilBrown | 8fa9dd2 | 2015-03-23 13:37:40 +1100 | [diff] [blame] | 990 | if (!(nd->flags & LOOKUP_RCU)) { |
| 991 | touch_atime(&last->link); |
| 992 | cond_resched(); |
| 993 | } else if (atime_needs_update(&last->link, inode)) { |
| 994 | if (unlikely(unlazy_walk(nd, NULL, 0))) |
| 995 | return ERR_PTR(-ECHILD); |
| 996 | touch_atime(&last->link); |
| 997 | } |
| 998 | |
NeilBrown | bda0be7 | 2015-03-23 13:37:39 +1100 | [diff] [blame] | 999 | error = security_inode_follow_link(dentry, inode, |
| 1000 | nd->flags & LOOKUP_RCU); |
| 1001 | if (unlikely(error)) |
Al Viro | 6920a44 | 2015-05-10 10:43:46 -0400 | [diff] [blame] | 1002 | return ERR_PTR(error); |
Al Viro | 36f3b4f | 2011-02-22 21:24:38 -0500 | [diff] [blame] | 1003 | |
Al Viro | 86acdca1 | 2009-12-22 23:45:11 -0500 | [diff] [blame] | 1004 | nd->last_type = LAST_BIND; |
Al Viro | d4dee48 | 2015-04-30 20:08:02 -0400 | [diff] [blame] | 1005 | res = inode->i_link; |
| 1006 | if (!res) { |
Al Viro | 8c1b456 | 2015-05-09 18:15:21 -0400 | [diff] [blame] | 1007 | if (nd->flags & LOOKUP_RCU) { |
| 1008 | if (unlikely(unlazy_walk(nd, NULL, 0))) |
| 1009 | return ERR_PTR(-ECHILD); |
| 1010 | } |
Al Viro | 6e77137 | 2015-05-02 13:37:52 -0400 | [diff] [blame] | 1011 | res = inode->i_op->follow_link(dentry, &last->cookie); |
Al Viro | fab51e8 | 2015-05-10 11:01:00 -0400 | [diff] [blame] | 1012 | if (IS_ERR_OR_NULL(res)) { |
Al Viro | 6920a44 | 2015-05-10 10:43:46 -0400 | [diff] [blame] | 1013 | last->cookie = NULL; |
Al Viro | fab51e8 | 2015-05-10 11:01:00 -0400 | [diff] [blame] | 1014 | return res; |
| 1015 | } |
Ian Kent | 051d381 | 2006-03-27 01:14:53 -0800 | [diff] [blame] | 1016 | } |
Al Viro | fab51e8 | 2015-05-10 11:01:00 -0400 | [diff] [blame] | 1017 | if (*res == '/') { |
Al Viro | 8c1b456 | 2015-05-09 18:15:21 -0400 | [diff] [blame] | 1018 | if (nd->flags & LOOKUP_RCU) { |
Al Viro | 8f47a016 | 2015-05-09 19:02:01 -0400 | [diff] [blame] | 1019 | struct dentry *d; |
| 1020 | if (!nd->root.mnt) |
| 1021 | set_root_rcu(nd); |
| 1022 | nd->path = nd->root; |
| 1023 | d = nd->path.dentry; |
| 1024 | nd->inode = d->d_inode; |
| 1025 | nd->seq = nd->root_seq; |
| 1026 | if (unlikely(read_seqcount_retry(&d->d_seq, nd->seq))) |
Al Viro | 8c1b456 | 2015-05-09 18:15:21 -0400 | [diff] [blame] | 1027 | return ERR_PTR(-ECHILD); |
Al Viro | 8f47a016 | 2015-05-09 19:02:01 -0400 | [diff] [blame] | 1028 | } else { |
| 1029 | if (!nd->root.mnt) |
| 1030 | set_root(nd); |
| 1031 | path_put(&nd->path); |
| 1032 | nd->path = nd->root; |
| 1033 | path_get(&nd->root); |
| 1034 | nd->inode = nd->path.dentry->d_inode; |
Al Viro | 8c1b456 | 2015-05-09 18:15:21 -0400 | [diff] [blame] | 1035 | } |
Al Viro | fab51e8 | 2015-05-10 11:01:00 -0400 | [diff] [blame] | 1036 | nd->flags |= LOOKUP_JUMPED; |
| 1037 | while (unlikely(*++res == '/')) |
| 1038 | ; |
| 1039 | } |
| 1040 | if (!*res) |
| 1041 | res = NULL; |
Al Viro | 0a959df | 2015-04-18 18:23:41 -0400 | [diff] [blame] | 1042 | return res; |
| 1043 | } |
Al Viro | 6d7b5aa | 2012-06-10 04:15:17 -0400 | [diff] [blame] | 1044 | |
David Howells | f015f126 | 2012-06-25 12:55:28 +0100 | [diff] [blame] | 1045 | /* |
| 1046 | * follow_up - Find the mountpoint of path's vfsmount |
| 1047 | * |
| 1048 | * Given a path, find the mountpoint of its source file system. |
| 1049 | * Replace @path with the path of the mountpoint in the parent mount. |
| 1050 | * Up is towards /. |
| 1051 | * |
| 1052 | * Return 1 if we went up a level and 0 if we were already at the |
| 1053 | * root. |
| 1054 | */ |
Al Viro | bab77eb | 2009-04-18 03:26:48 -0400 | [diff] [blame] | 1055 | int follow_up(struct path *path) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1056 | { |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 1057 | struct mount *mnt = real_mount(path->mnt); |
| 1058 | struct mount *parent; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1059 | struct dentry *mountpoint; |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 1060 | |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 1061 | read_seqlock_excl(&mount_lock); |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 1062 | parent = mnt->mnt_parent; |
Al Viro | 3c0a616 | 2012-07-18 17:32:50 +0400 | [diff] [blame] | 1063 | if (parent == mnt) { |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 1064 | read_sequnlock_excl(&mount_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1065 | return 0; |
| 1066 | } |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 1067 | mntget(&parent->mnt); |
Al Viro | a73324d | 2011-11-24 22:25:07 -0500 | [diff] [blame] | 1068 | mountpoint = dget(mnt->mnt_mountpoint); |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 1069 | read_sequnlock_excl(&mount_lock); |
Al Viro | bab77eb | 2009-04-18 03:26:48 -0400 | [diff] [blame] | 1070 | dput(path->dentry); |
| 1071 | path->dentry = mountpoint; |
| 1072 | mntput(path->mnt); |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 1073 | path->mnt = &parent->mnt; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1074 | return 1; |
| 1075 | } |
Al Viro | 4d35950 | 2014-03-14 12:20:17 -0400 | [diff] [blame] | 1076 | EXPORT_SYMBOL(follow_up); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1077 | |
Nick Piggin | b5c84bf | 2011-01-07 17:49:38 +1100 | [diff] [blame] | 1078 | /* |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1079 | * Perform an automount |
| 1080 | * - return -EISDIR to tell follow_managed() to stop and return the path we |
| 1081 | * were called with. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1082 | */ |
NeilBrown | 756daf2 | 2015-03-23 13:37:38 +1100 | [diff] [blame] | 1083 | static int follow_automount(struct path *path, struct nameidata *nd, |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1084 | bool *need_mntput) |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1085 | { |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1086 | struct vfsmount *mnt; |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 1087 | int err; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1088 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1089 | if (!path->dentry->d_op || !path->dentry->d_op->d_automount) |
| 1090 | return -EREMOTE; |
Al Viro | 463ffb2 | 2005-06-06 13:36:05 -0700 | [diff] [blame] | 1091 | |
Miklos Szeredi | 0ec26fd | 2011-09-05 18:06:26 +0200 | [diff] [blame] | 1092 | /* We don't want to mount if someone's just doing a stat - |
| 1093 | * unless they're stat'ing a directory and appended a '/' to |
| 1094 | * the name. |
| 1095 | * |
| 1096 | * We do, however, want to mount if someone wants to open or |
| 1097 | * create a file of any type under the mountpoint, wants to |
| 1098 | * traverse through the mountpoint or wants to open the |
| 1099 | * mounted directory. Also, autofs may mark negative dentries |
| 1100 | * as being automount points. These will need the attentions |
| 1101 | * of the daemon to instantiate them before they can be used. |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1102 | */ |
NeilBrown | 756daf2 | 2015-03-23 13:37:38 +1100 | [diff] [blame] | 1103 | if (!(nd->flags & (LOOKUP_PARENT | LOOKUP_DIRECTORY | |
| 1104 | LOOKUP_OPEN | LOOKUP_CREATE | LOOKUP_AUTOMOUNT)) && |
Miklos Szeredi | 0ec26fd | 2011-09-05 18:06:26 +0200 | [diff] [blame] | 1105 | path->dentry->d_inode) |
| 1106 | return -EISDIR; |
| 1107 | |
NeilBrown | 756daf2 | 2015-03-23 13:37:38 +1100 | [diff] [blame] | 1108 | nd->total_link_count++; |
| 1109 | if (nd->total_link_count >= 40) |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1110 | return -ELOOP; |
| 1111 | |
| 1112 | mnt = path->dentry->d_op->d_automount(path); |
| 1113 | if (IS_ERR(mnt)) { |
| 1114 | /* |
| 1115 | * The filesystem is allowed to return -EISDIR here to indicate |
| 1116 | * it doesn't want to automount. For instance, autofs would do |
| 1117 | * this so that its userspace daemon can mount on this dentry. |
| 1118 | * |
| 1119 | * However, we can only permit this if it's a terminal point in |
| 1120 | * the path being looked up; if it wasn't then the remainder of |
| 1121 | * the path is inaccessible and we should say so. |
| 1122 | */ |
NeilBrown | 756daf2 | 2015-03-23 13:37:38 +1100 | [diff] [blame] | 1123 | if (PTR_ERR(mnt) == -EISDIR && (nd->flags & LOOKUP_PARENT)) |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1124 | return -EREMOTE; |
| 1125 | return PTR_ERR(mnt); |
| 1126 | } |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 1127 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1128 | if (!mnt) /* mount collision */ |
| 1129 | return 0; |
| 1130 | |
Al Viro | 8aef188 | 2011-06-16 15:10:06 +0100 | [diff] [blame] | 1131 | if (!*need_mntput) { |
| 1132 | /* lock_mount() may release path->mnt on error */ |
| 1133 | mntget(path->mnt); |
| 1134 | *need_mntput = true; |
| 1135 | } |
Al Viro | 19a167a | 2011-01-17 01:35:23 -0500 | [diff] [blame] | 1136 | err = finish_automount(mnt, path); |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 1137 | |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 1138 | switch (err) { |
| 1139 | case -EBUSY: |
| 1140 | /* Someone else made a mount here whilst we were busy */ |
Al Viro | 19a167a | 2011-01-17 01:35:23 -0500 | [diff] [blame] | 1141 | return 0; |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 1142 | case 0: |
Al Viro | 8aef188 | 2011-06-16 15:10:06 +0100 | [diff] [blame] | 1143 | path_put(path); |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 1144 | path->mnt = mnt; |
| 1145 | path->dentry = dget(mnt->mnt_root); |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 1146 | return 0; |
Al Viro | 19a167a | 2011-01-17 01:35:23 -0500 | [diff] [blame] | 1147 | default: |
| 1148 | return err; |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 1149 | } |
Al Viro | 19a167a | 2011-01-17 01:35:23 -0500 | [diff] [blame] | 1150 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1151 | } |
| 1152 | |
| 1153 | /* |
| 1154 | * Handle a dentry that is managed in some way. |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 1155 | * - Flagged for transit management (autofs) |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1156 | * - Flagged as mountpoint |
| 1157 | * - Flagged as automount point |
| 1158 | * |
| 1159 | * This may only be called in refwalk mode. |
| 1160 | * |
| 1161 | * Serialization is taken care of in namespace.c |
| 1162 | */ |
NeilBrown | 756daf2 | 2015-03-23 13:37:38 +1100 | [diff] [blame] | 1163 | static int follow_managed(struct path *path, struct nameidata *nd) |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1164 | { |
Al Viro | 8aef188 | 2011-06-16 15:10:06 +0100 | [diff] [blame] | 1165 | struct vfsmount *mnt = path->mnt; /* held by caller, must be left alone */ |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1166 | unsigned managed; |
| 1167 | bool need_mntput = false; |
Al Viro | 8aef188 | 2011-06-16 15:10:06 +0100 | [diff] [blame] | 1168 | int ret = 0; |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1169 | |
| 1170 | /* Given that we're not holding a lock here, we retain the value in a |
| 1171 | * local variable for each dentry as we look at it so that we don't see |
| 1172 | * the components of that value change under us */ |
| 1173 | while (managed = ACCESS_ONCE(path->dentry->d_flags), |
| 1174 | managed &= DCACHE_MANAGED_DENTRY, |
| 1175 | unlikely(managed != 0)) { |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 1176 | /* Allow the filesystem to manage the transit without i_mutex |
| 1177 | * being held. */ |
| 1178 | if (managed & DCACHE_MANAGE_TRANSIT) { |
| 1179 | BUG_ON(!path->dentry->d_op); |
| 1180 | BUG_ON(!path->dentry->d_op->d_manage); |
Al Viro | 1aed3e4 | 2011-03-18 09:09:02 -0400 | [diff] [blame] | 1181 | ret = path->dentry->d_op->d_manage(path->dentry, false); |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 1182 | if (ret < 0) |
Al Viro | 8aef188 | 2011-06-16 15:10:06 +0100 | [diff] [blame] | 1183 | break; |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 1184 | } |
| 1185 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1186 | /* Transit to a mounted filesystem. */ |
| 1187 | if (managed & DCACHE_MOUNTED) { |
| 1188 | struct vfsmount *mounted = lookup_mnt(path); |
| 1189 | if (mounted) { |
| 1190 | dput(path->dentry); |
| 1191 | if (need_mntput) |
| 1192 | mntput(path->mnt); |
| 1193 | path->mnt = mounted; |
| 1194 | path->dentry = dget(mounted->mnt_root); |
| 1195 | need_mntput = true; |
| 1196 | continue; |
| 1197 | } |
| 1198 | |
| 1199 | /* Something is mounted on this dentry in another |
| 1200 | * namespace and/or whatever was mounted there in this |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 1201 | * namespace got unmounted before lookup_mnt() could |
| 1202 | * get it */ |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1203 | } |
| 1204 | |
| 1205 | /* Handle an automount point */ |
| 1206 | if (managed & DCACHE_NEED_AUTOMOUNT) { |
NeilBrown | 756daf2 | 2015-03-23 13:37:38 +1100 | [diff] [blame] | 1207 | ret = follow_automount(path, nd, &need_mntput); |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1208 | if (ret < 0) |
Al Viro | 8aef188 | 2011-06-16 15:10:06 +0100 | [diff] [blame] | 1209 | break; |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1210 | continue; |
| 1211 | } |
| 1212 | |
| 1213 | /* We didn't change the current path point */ |
| 1214 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1215 | } |
Al Viro | 8aef188 | 2011-06-16 15:10:06 +0100 | [diff] [blame] | 1216 | |
| 1217 | if (need_mntput && path->mnt == mnt) |
| 1218 | mntput(path->mnt); |
| 1219 | if (ret == -EISDIR) |
| 1220 | ret = 0; |
Al Viro | 8402752 | 2015-04-22 10:30:08 -0400 | [diff] [blame] | 1221 | if (need_mntput) |
| 1222 | nd->flags |= LOOKUP_JUMPED; |
| 1223 | if (unlikely(ret < 0)) |
| 1224 | path_put_conditional(path, nd); |
| 1225 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1226 | } |
| 1227 | |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 1228 | int follow_down_one(struct path *path) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1229 | { |
| 1230 | struct vfsmount *mounted; |
| 1231 | |
Al Viro | 1c755af | 2009-04-18 14:06:57 -0400 | [diff] [blame] | 1232 | mounted = lookup_mnt(path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1233 | if (mounted) { |
Al Viro | 9393bd0 | 2009-04-18 13:58:15 -0400 | [diff] [blame] | 1234 | dput(path->dentry); |
| 1235 | mntput(path->mnt); |
| 1236 | path->mnt = mounted; |
| 1237 | path->dentry = dget(mounted->mnt_root); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1238 | return 1; |
| 1239 | } |
| 1240 | return 0; |
| 1241 | } |
Al Viro | 4d35950 | 2014-03-14 12:20:17 -0400 | [diff] [blame] | 1242 | EXPORT_SYMBOL(follow_down_one); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1243 | |
NeilBrown | b8faf03 | 2014-08-04 17:06:29 +1000 | [diff] [blame] | 1244 | static inline int managed_dentry_rcu(struct dentry *dentry) |
Ian Kent | 62a7375 | 2011-03-25 01:51:02 +0800 | [diff] [blame] | 1245 | { |
NeilBrown | b8faf03 | 2014-08-04 17:06:29 +1000 | [diff] [blame] | 1246 | return (dentry->d_flags & DCACHE_MANAGE_TRANSIT) ? |
| 1247 | dentry->d_op->d_manage(dentry, true) : 0; |
Ian Kent | 62a7375 | 2011-03-25 01:51:02 +0800 | [diff] [blame] | 1248 | } |
| 1249 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1250 | /* |
Al Viro | 287548e | 2011-05-27 06:50:06 -0400 | [diff] [blame] | 1251 | * Try to skip to top of mountpoint pile in rcuwalk mode. Fail if |
| 1252 | * we meet a managed dentry that would need blocking. |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1253 | */ |
| 1254 | static bool __follow_mount_rcu(struct nameidata *nd, struct path *path, |
Al Viro | 254cf58 | 2015-05-05 09:40:46 -0400 | [diff] [blame] | 1255 | struct inode **inode, unsigned *seqp) |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1256 | { |
Ian Kent | 62a7375 | 2011-03-25 01:51:02 +0800 | [diff] [blame] | 1257 | for (;;) { |
Al Viro | c710536 | 2011-11-24 18:22:03 -0500 | [diff] [blame] | 1258 | struct mount *mounted; |
Ian Kent | 62a7375 | 2011-03-25 01:51:02 +0800 | [diff] [blame] | 1259 | /* |
| 1260 | * Don't forget we might have a non-mountpoint managed dentry |
| 1261 | * that wants to block transit. |
| 1262 | */ |
NeilBrown | b8faf03 | 2014-08-04 17:06:29 +1000 | [diff] [blame] | 1263 | switch (managed_dentry_rcu(path->dentry)) { |
| 1264 | case -ECHILD: |
| 1265 | default: |
David Howells | ab90911 | 2011-01-14 18:46:51 +0000 | [diff] [blame] | 1266 | return false; |
NeilBrown | b8faf03 | 2014-08-04 17:06:29 +1000 | [diff] [blame] | 1267 | case -EISDIR: |
| 1268 | return true; |
| 1269 | case 0: |
| 1270 | break; |
| 1271 | } |
Ian Kent | 62a7375 | 2011-03-25 01:51:02 +0800 | [diff] [blame] | 1272 | |
| 1273 | if (!d_mountpoint(path->dentry)) |
NeilBrown | b8faf03 | 2014-08-04 17:06:29 +1000 | [diff] [blame] | 1274 | return !(path->dentry->d_flags & DCACHE_NEED_AUTOMOUNT); |
Ian Kent | 62a7375 | 2011-03-25 01:51:02 +0800 | [diff] [blame] | 1275 | |
Al Viro | 474279d | 2013-10-01 16:11:26 -0400 | [diff] [blame] | 1276 | mounted = __lookup_mnt(path->mnt, path->dentry); |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1277 | if (!mounted) |
| 1278 | break; |
Al Viro | c710536 | 2011-11-24 18:22:03 -0500 | [diff] [blame] | 1279 | path->mnt = &mounted->mnt; |
| 1280 | path->dentry = mounted->mnt.mnt_root; |
Al Viro | a3fbbde | 2011-11-07 21:21:26 +0000 | [diff] [blame] | 1281 | nd->flags |= LOOKUP_JUMPED; |
Al Viro | 254cf58 | 2015-05-05 09:40:46 -0400 | [diff] [blame] | 1282 | *seqp = read_seqcount_begin(&path->dentry->d_seq); |
Linus Torvalds | 5943026 | 2011-07-18 15:43:29 -0700 | [diff] [blame] | 1283 | /* |
| 1284 | * Update the inode too. We don't need to re-check the |
| 1285 | * dentry sequence number here after this d_inode read, |
| 1286 | * because a mount-point is always pinned. |
| 1287 | */ |
| 1288 | *inode = path->dentry->d_inode; |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1289 | } |
Al Viro | f5be3e2912 | 2014-09-13 21:50:45 -0400 | [diff] [blame] | 1290 | return !read_seqretry(&mount_lock, nd->m_seq) && |
NeilBrown | b8faf03 | 2014-08-04 17:06:29 +1000 | [diff] [blame] | 1291 | !(path->dentry->d_flags & DCACHE_NEED_AUTOMOUNT); |
Al Viro | 287548e | 2011-05-27 06:50:06 -0400 | [diff] [blame] | 1292 | } |
| 1293 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1294 | static int follow_dotdot_rcu(struct nameidata *nd) |
| 1295 | { |
Al Viro | 4023bfc | 2014-09-13 21:59:43 -0400 | [diff] [blame] | 1296 | struct inode *inode = nd->inode; |
Al Viro | 7bd8837 | 2014-09-13 21:55:46 -0400 | [diff] [blame] | 1297 | if (!nd->root.mnt) |
| 1298 | set_root_rcu(nd); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1299 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1300 | while (1) { |
Al Viro | aed434a | 2015-05-12 12:22:47 -0400 | [diff] [blame] | 1301 | if (path_equal(&nd->path, &nd->root)) |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1302 | break; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1303 | if (nd->path.dentry != nd->path.mnt->mnt_root) { |
| 1304 | struct dentry *old = nd->path.dentry; |
| 1305 | struct dentry *parent = old->d_parent; |
| 1306 | unsigned seq; |
| 1307 | |
Al Viro | 4023bfc | 2014-09-13 21:59:43 -0400 | [diff] [blame] | 1308 | inode = parent->d_inode; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1309 | seq = read_seqcount_begin(&parent->d_seq); |
Al Viro | aed434a | 2015-05-12 12:22:47 -0400 | [diff] [blame] | 1310 | if (unlikely(read_seqcount_retry(&old->d_seq, nd->seq))) |
| 1311 | return -ECHILD; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1312 | nd->path.dentry = parent; |
| 1313 | nd->seq = seq; |
Eric W. Biederman | 397d425 | 2015-08-15 20:27:13 -0500 | [diff] [blame] | 1314 | if (unlikely(!path_connected(&nd->path))) |
| 1315 | return -ENOENT; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1316 | break; |
Al Viro | aed434a | 2015-05-12 12:22:47 -0400 | [diff] [blame] | 1317 | } else { |
| 1318 | struct mount *mnt = real_mount(nd->path.mnt); |
| 1319 | struct mount *mparent = mnt->mnt_parent; |
| 1320 | struct dentry *mountpoint = mnt->mnt_mountpoint; |
| 1321 | struct inode *inode2 = mountpoint->d_inode; |
| 1322 | unsigned seq = read_seqcount_begin(&mountpoint->d_seq); |
| 1323 | if (unlikely(read_seqretry(&mount_lock, nd->m_seq))) |
| 1324 | return -ECHILD; |
| 1325 | if (&mparent->mnt == nd->path.mnt) |
| 1326 | break; |
| 1327 | /* we know that mountpoint was pinned */ |
| 1328 | nd->path.dentry = mountpoint; |
| 1329 | nd->path.mnt = &mparent->mnt; |
| 1330 | inode = inode2; |
| 1331 | nd->seq = seq; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1332 | } |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1333 | } |
Al Viro | aed434a | 2015-05-12 12:22:47 -0400 | [diff] [blame] | 1334 | while (unlikely(d_mountpoint(nd->path.dentry))) { |
Al Viro | b37199e | 2014-03-20 15:18:22 -0400 | [diff] [blame] | 1335 | struct mount *mounted; |
| 1336 | mounted = __lookup_mnt(nd->path.mnt, nd->path.dentry); |
Al Viro | aed434a | 2015-05-12 12:22:47 -0400 | [diff] [blame] | 1337 | if (unlikely(read_seqretry(&mount_lock, nd->m_seq))) |
| 1338 | return -ECHILD; |
Al Viro | b37199e | 2014-03-20 15:18:22 -0400 | [diff] [blame] | 1339 | if (!mounted) |
| 1340 | break; |
| 1341 | nd->path.mnt = &mounted->mnt; |
| 1342 | nd->path.dentry = mounted->mnt.mnt_root; |
Al Viro | 4023bfc | 2014-09-13 21:59:43 -0400 | [diff] [blame] | 1343 | inode = nd->path.dentry->d_inode; |
Al Viro | b37199e | 2014-03-20 15:18:22 -0400 | [diff] [blame] | 1344 | nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq); |
Al Viro | b37199e | 2014-03-20 15:18:22 -0400 | [diff] [blame] | 1345 | } |
Al Viro | 4023bfc | 2014-09-13 21:59:43 -0400 | [diff] [blame] | 1346 | nd->inode = inode; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1347 | return 0; |
| 1348 | } |
| 1349 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1350 | /* |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 1351 | * Follow down to the covering mount currently visible to userspace. At each |
| 1352 | * point, the filesystem owning that dentry may be queried as to whether the |
| 1353 | * caller is permitted to proceed or not. |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 1354 | */ |
Al Viro | 7cc90cc | 2011-03-18 09:04:20 -0400 | [diff] [blame] | 1355 | int follow_down(struct path *path) |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 1356 | { |
| 1357 | unsigned managed; |
| 1358 | int ret; |
| 1359 | |
| 1360 | while (managed = ACCESS_ONCE(path->dentry->d_flags), |
| 1361 | unlikely(managed & DCACHE_MANAGED_DENTRY)) { |
| 1362 | /* Allow the filesystem to manage the transit without i_mutex |
| 1363 | * being held. |
| 1364 | * |
| 1365 | * We indicate to the filesystem if someone is trying to mount |
| 1366 | * something here. This gives autofs the chance to deny anyone |
| 1367 | * other than its daemon the right to mount on its |
| 1368 | * superstructure. |
| 1369 | * |
| 1370 | * The filesystem may sleep at this point. |
| 1371 | */ |
| 1372 | if (managed & DCACHE_MANAGE_TRANSIT) { |
| 1373 | BUG_ON(!path->dentry->d_op); |
| 1374 | BUG_ON(!path->dentry->d_op->d_manage); |
David Howells | ab90911 | 2011-01-14 18:46:51 +0000 | [diff] [blame] | 1375 | ret = path->dentry->d_op->d_manage( |
Al Viro | 1aed3e4 | 2011-03-18 09:09:02 -0400 | [diff] [blame] | 1376 | path->dentry, false); |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 1377 | if (ret < 0) |
| 1378 | return ret == -EISDIR ? 0 : ret; |
| 1379 | } |
| 1380 | |
| 1381 | /* Transit to a mounted filesystem. */ |
| 1382 | if (managed & DCACHE_MOUNTED) { |
| 1383 | struct vfsmount *mounted = lookup_mnt(path); |
| 1384 | if (!mounted) |
| 1385 | break; |
| 1386 | dput(path->dentry); |
| 1387 | mntput(path->mnt); |
| 1388 | path->mnt = mounted; |
| 1389 | path->dentry = dget(mounted->mnt_root); |
| 1390 | continue; |
| 1391 | } |
| 1392 | |
| 1393 | /* Don't handle automount points here */ |
| 1394 | break; |
| 1395 | } |
| 1396 | return 0; |
| 1397 | } |
Al Viro | 4d35950 | 2014-03-14 12:20:17 -0400 | [diff] [blame] | 1398 | EXPORT_SYMBOL(follow_down); |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 1399 | |
| 1400 | /* |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1401 | * Skip to top of mountpoint pile in refwalk mode for follow_dotdot() |
| 1402 | */ |
| 1403 | static void follow_mount(struct path *path) |
| 1404 | { |
| 1405 | while (d_mountpoint(path->dentry)) { |
| 1406 | struct vfsmount *mounted = lookup_mnt(path); |
| 1407 | if (!mounted) |
| 1408 | break; |
| 1409 | dput(path->dentry); |
| 1410 | mntput(path->mnt); |
| 1411 | path->mnt = mounted; |
| 1412 | path->dentry = dget(mounted->mnt_root); |
| 1413 | } |
| 1414 | } |
| 1415 | |
Eric W. Biederman | 397d425 | 2015-08-15 20:27:13 -0500 | [diff] [blame] | 1416 | static int follow_dotdot(struct nameidata *nd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1417 | { |
Al Viro | 7bd8837 | 2014-09-13 21:55:46 -0400 | [diff] [blame] | 1418 | if (!nd->root.mnt) |
| 1419 | set_root(nd); |
Andreas Mohr | e518ddb | 2006-09-29 02:01:22 -0700 | [diff] [blame] | 1420 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1421 | while(1) { |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 1422 | struct dentry *old = nd->path.dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1423 | |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 1424 | if (nd->path.dentry == nd->root.dentry && |
| 1425 | nd->path.mnt == nd->root.mnt) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1426 | break; |
| 1427 | } |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 1428 | if (nd->path.dentry != nd->path.mnt->mnt_root) { |
Al Viro | 3088dd7 | 2010-01-30 15:47:29 -0500 | [diff] [blame] | 1429 | /* rare case of legitimate dget_parent()... */ |
| 1430 | nd->path.dentry = dget_parent(nd->path.dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1431 | dput(old); |
Eric W. Biederman | 397d425 | 2015-08-15 20:27:13 -0500 | [diff] [blame] | 1432 | if (unlikely(!path_connected(&nd->path))) |
| 1433 | return -ENOENT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1434 | break; |
| 1435 | } |
Al Viro | 3088dd7 | 2010-01-30 15:47:29 -0500 | [diff] [blame] | 1436 | if (!follow_up(&nd->path)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1437 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1438 | } |
Al Viro | 79ed022 | 2009-04-18 13:59:41 -0400 | [diff] [blame] | 1439 | follow_mount(&nd->path); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1440 | nd->inode = nd->path.dentry->d_inode; |
Eric W. Biederman | 397d425 | 2015-08-15 20:27:13 -0500 | [diff] [blame] | 1441 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1442 | } |
| 1443 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1444 | /* |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1445 | * This looks up the name in dcache, possibly revalidates the old dentry and |
| 1446 | * allocates a new one if not found or not valid. In the need_lookup argument |
| 1447 | * returns whether i_op->lookup is necessary. |
| 1448 | * |
| 1449 | * dir->d_inode->i_mutex must be held |
Nick Piggin | baa0389 | 2010-08-18 04:37:31 +1000 | [diff] [blame] | 1450 | */ |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1451 | static struct dentry *lookup_dcache(struct qstr *name, struct dentry *dir, |
Al Viro | 201f956 | 2012-06-22 12:42:10 +0400 | [diff] [blame] | 1452 | unsigned int flags, bool *need_lookup) |
Nick Piggin | baa0389 | 2010-08-18 04:37:31 +1000 | [diff] [blame] | 1453 | { |
Nick Piggin | baa0389 | 2010-08-18 04:37:31 +1000 | [diff] [blame] | 1454 | struct dentry *dentry; |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1455 | int error; |
Nick Piggin | baa0389 | 2010-08-18 04:37:31 +1000 | [diff] [blame] | 1456 | |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1457 | *need_lookup = false; |
| 1458 | dentry = d_lookup(dir, name); |
| 1459 | if (dentry) { |
Jeff Layton | 39e3c95 | 2012-11-28 11:30:53 -0500 | [diff] [blame] | 1460 | if (dentry->d_flags & DCACHE_OP_REVALIDATE) { |
Al Viro | 201f956 | 2012-06-22 12:42:10 +0400 | [diff] [blame] | 1461 | error = d_revalidate(dentry, flags); |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1462 | if (unlikely(error <= 0)) { |
| 1463 | if (error < 0) { |
| 1464 | dput(dentry); |
| 1465 | return ERR_PTR(error); |
Eric W. Biederman | 5542aa2 | 2014-02-13 09:46:25 -0800 | [diff] [blame] | 1466 | } else { |
| 1467 | d_invalidate(dentry); |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1468 | dput(dentry); |
| 1469 | dentry = NULL; |
| 1470 | } |
| 1471 | } |
| 1472 | } |
| 1473 | } |
Nick Piggin | baa0389 | 2010-08-18 04:37:31 +1000 | [diff] [blame] | 1474 | |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1475 | if (!dentry) { |
| 1476 | dentry = d_alloc(dir, name); |
| 1477 | if (unlikely(!dentry)) |
| 1478 | return ERR_PTR(-ENOMEM); |
Nick Piggin | baa0389 | 2010-08-18 04:37:31 +1000 | [diff] [blame] | 1479 | |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1480 | *need_lookup = true; |
Nick Piggin | baa0389 | 2010-08-18 04:37:31 +1000 | [diff] [blame] | 1481 | } |
| 1482 | return dentry; |
| 1483 | } |
| 1484 | |
| 1485 | /* |
J. Bruce Fields | 13a2c3b | 2013-10-23 16:09:16 -0400 | [diff] [blame] | 1486 | * Call i_op->lookup on the dentry. The dentry must be negative and |
| 1487 | * unhashed. |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1488 | * |
| 1489 | * dir->d_inode->i_mutex must be held |
Josef Bacik | 44396f4 | 2011-05-31 11:58:49 -0400 | [diff] [blame] | 1490 | */ |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1491 | static struct dentry *lookup_real(struct inode *dir, struct dentry *dentry, |
Al Viro | 72bd866 | 2012-06-10 17:17:17 -0400 | [diff] [blame] | 1492 | unsigned int flags) |
Josef Bacik | 44396f4 | 2011-05-31 11:58:49 -0400 | [diff] [blame] | 1493 | { |
Josef Bacik | 44396f4 | 2011-05-31 11:58:49 -0400 | [diff] [blame] | 1494 | struct dentry *old; |
| 1495 | |
| 1496 | /* Don't create child dentry for a dead directory. */ |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1497 | if (unlikely(IS_DEADDIR(dir))) { |
Miklos Szeredi | e188dc0 | 2012-02-03 14:25:18 +0100 | [diff] [blame] | 1498 | dput(dentry); |
Josef Bacik | 44396f4 | 2011-05-31 11:58:49 -0400 | [diff] [blame] | 1499 | return ERR_PTR(-ENOENT); |
Miklos Szeredi | e188dc0 | 2012-02-03 14:25:18 +0100 | [diff] [blame] | 1500 | } |
Josef Bacik | 44396f4 | 2011-05-31 11:58:49 -0400 | [diff] [blame] | 1501 | |
Al Viro | 72bd866 | 2012-06-10 17:17:17 -0400 | [diff] [blame] | 1502 | old = dir->i_op->lookup(dir, dentry, flags); |
Josef Bacik | 44396f4 | 2011-05-31 11:58:49 -0400 | [diff] [blame] | 1503 | if (unlikely(old)) { |
| 1504 | dput(dentry); |
| 1505 | dentry = old; |
| 1506 | } |
| 1507 | return dentry; |
| 1508 | } |
| 1509 | |
Al Viro | a325554 | 2012-03-30 14:41:51 -0400 | [diff] [blame] | 1510 | static struct dentry *__lookup_hash(struct qstr *name, |
Al Viro | 72bd866 | 2012-06-10 17:17:17 -0400 | [diff] [blame] | 1511 | struct dentry *base, unsigned int flags) |
Al Viro | a325554 | 2012-03-30 14:41:51 -0400 | [diff] [blame] | 1512 | { |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1513 | bool need_lookup; |
Al Viro | a325554 | 2012-03-30 14:41:51 -0400 | [diff] [blame] | 1514 | struct dentry *dentry; |
| 1515 | |
Al Viro | 72bd866 | 2012-06-10 17:17:17 -0400 | [diff] [blame] | 1516 | dentry = lookup_dcache(name, base, flags, &need_lookup); |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1517 | if (!need_lookup) |
| 1518 | return dentry; |
Al Viro | a325554 | 2012-03-30 14:41:51 -0400 | [diff] [blame] | 1519 | |
Al Viro | 72bd866 | 2012-06-10 17:17:17 -0400 | [diff] [blame] | 1520 | return lookup_real(base->d_inode, dentry, flags); |
Al Viro | a325554 | 2012-03-30 14:41:51 -0400 | [diff] [blame] | 1521 | } |
| 1522 | |
Josef Bacik | 44396f4 | 2011-05-31 11:58:49 -0400 | [diff] [blame] | 1523 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1524 | * It's more convoluted than I'd like it to be, but... it's still fairly |
| 1525 | * small and for now I'd prefer to have fast path as straight as possible. |
| 1526 | * It _is_ time-critical. |
| 1527 | */ |
Al Viro | e97cdc8 | 2013-01-24 18:16:00 -0500 | [diff] [blame] | 1528 | static int lookup_fast(struct nameidata *nd, |
Al Viro | 254cf58 | 2015-05-05 09:40:46 -0400 | [diff] [blame] | 1529 | struct path *path, struct inode **inode, |
| 1530 | unsigned *seqp) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1531 | { |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 1532 | struct vfsmount *mnt = nd->path.mnt; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1533 | struct dentry *dentry, *parent = nd->path.dentry; |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1534 | int need_reval = 1; |
| 1535 | int status = 1; |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1536 | int err; |
| 1537 | |
Al Viro | 3cac260 | 2009-08-13 18:27:43 +0400 | [diff] [blame] | 1538 | /* |
Nick Piggin | b04f784 | 2010-08-18 04:37:34 +1000 | [diff] [blame] | 1539 | * Rename seqlock is not required here because in the off chance |
| 1540 | * of a false negative due to a concurrent rename, we're going to |
| 1541 | * do the non-racy lookup, below. |
| 1542 | */ |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1543 | if (nd->flags & LOOKUP_RCU) { |
| 1544 | unsigned seq; |
Al Viro | 766c4cb | 2015-05-07 19:24:57 -0400 | [diff] [blame] | 1545 | bool negative; |
Linus Torvalds | da53be1 | 2013-05-21 15:22:44 -0700 | [diff] [blame] | 1546 | dentry = __d_lookup_rcu(parent, &nd->last, &seq); |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1547 | if (!dentry) |
| 1548 | goto unlazy; |
| 1549 | |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1550 | /* |
| 1551 | * This sequence count validates that the inode matches |
| 1552 | * the dentry name information from lookup. |
| 1553 | */ |
David Howells | 63afdfc | 2015-05-06 15:59:00 +0100 | [diff] [blame] | 1554 | *inode = d_backing_inode(dentry); |
Al Viro | 766c4cb | 2015-05-07 19:24:57 -0400 | [diff] [blame] | 1555 | negative = d_is_negative(dentry); |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1556 | if (read_seqcount_retry(&dentry->d_seq, seq)) |
| 1557 | return -ECHILD; |
| 1558 | |
| 1559 | /* |
| 1560 | * This sequence count validates that the parent had no |
| 1561 | * changes while we did the lookup of the dentry above. |
| 1562 | * |
| 1563 | * The memory barrier in read_seqcount_begin of child is |
| 1564 | * enough, we can use __read_seqcount_retry here. |
| 1565 | */ |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1566 | if (__read_seqcount_retry(&parent->d_seq, nd->seq)) |
| 1567 | return -ECHILD; |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1568 | |
Al Viro | 254cf58 | 2015-05-05 09:40:46 -0400 | [diff] [blame] | 1569 | *seqp = seq; |
Al Viro | 2464308 | 2011-02-15 01:26:22 -0500 | [diff] [blame] | 1570 | if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE)) { |
Al Viro | 4ce16ef3 | 2012-06-10 16:10:59 -0400 | [diff] [blame] | 1571 | status = d_revalidate(dentry, nd->flags); |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1572 | if (unlikely(status <= 0)) { |
| 1573 | if (status != -ECHILD) |
| 1574 | need_reval = 0; |
| 1575 | goto unlazy; |
| 1576 | } |
Al Viro | 2464308 | 2011-02-15 01:26:22 -0500 | [diff] [blame] | 1577 | } |
Trond Myklebust | daf3761 | 2015-10-09 13:44:34 -0400 | [diff] [blame] | 1578 | /* |
| 1579 | * Note: do negative dentry check after revalidation in |
| 1580 | * case that drops it. |
| 1581 | */ |
| 1582 | if (negative) |
| 1583 | return -ENOENT; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1584 | path->mnt = mnt; |
| 1585 | path->dentry = dentry; |
Al Viro | 254cf58 | 2015-05-05 09:40:46 -0400 | [diff] [blame] | 1586 | if (likely(__follow_mount_rcu(nd, path, inode, seqp))) |
NeilBrown | b8faf03 | 2014-08-04 17:06:29 +1000 | [diff] [blame] | 1587 | return 0; |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1588 | unlazy: |
Al Viro | 254cf58 | 2015-05-05 09:40:46 -0400 | [diff] [blame] | 1589 | if (unlazy_walk(nd, dentry, seq)) |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 1590 | return -ECHILD; |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1591 | } else { |
Al Viro | e97cdc8 | 2013-01-24 18:16:00 -0500 | [diff] [blame] | 1592 | dentry = __d_lookup(parent, &nd->last); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1593 | } |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1594 | |
Al Viro | 81e6f52 | 2012-03-30 14:48:04 -0400 | [diff] [blame] | 1595 | if (unlikely(!dentry)) |
| 1596 | goto need_lookup; |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1597 | |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1598 | if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE) && need_reval) |
Al Viro | 4ce16ef3 | 2012-06-10 16:10:59 -0400 | [diff] [blame] | 1599 | status = d_revalidate(dentry, nd->flags); |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1600 | if (unlikely(status <= 0)) { |
| 1601 | if (status < 0) { |
| 1602 | dput(dentry); |
| 1603 | return status; |
| 1604 | } |
Eric W. Biederman | 5542aa2 | 2014-02-13 09:46:25 -0800 | [diff] [blame] | 1605 | d_invalidate(dentry); |
| 1606 | dput(dentry); |
| 1607 | goto need_lookup; |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1608 | } |
Miklos Szeredi | 697f514 | 2012-05-21 17:30:05 +0200 | [diff] [blame] | 1609 | |
Al Viro | 766c4cb | 2015-05-07 19:24:57 -0400 | [diff] [blame] | 1610 | if (unlikely(d_is_negative(dentry))) { |
| 1611 | dput(dentry); |
| 1612 | return -ENOENT; |
| 1613 | } |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1614 | path->mnt = mnt; |
| 1615 | path->dentry = dentry; |
NeilBrown | 756daf2 | 2015-03-23 13:37:38 +1100 | [diff] [blame] | 1616 | err = follow_managed(path, nd); |
Al Viro | 8402752 | 2015-04-22 10:30:08 -0400 | [diff] [blame] | 1617 | if (likely(!err)) |
David Howells | 63afdfc | 2015-05-06 15:59:00 +0100 | [diff] [blame] | 1618 | *inode = d_backing_inode(path->dentry); |
Al Viro | 8402752 | 2015-04-22 10:30:08 -0400 | [diff] [blame] | 1619 | return err; |
Al Viro | 81e6f52 | 2012-03-30 14:48:04 -0400 | [diff] [blame] | 1620 | |
| 1621 | need_lookup: |
Miklos Szeredi | 697f514 | 2012-05-21 17:30:05 +0200 | [diff] [blame] | 1622 | return 1; |
| 1623 | } |
| 1624 | |
| 1625 | /* Fast lookup failed, do it the slow way */ |
Al Viro | cc2a527 | 2013-01-24 18:19:49 -0500 | [diff] [blame] | 1626 | static int lookup_slow(struct nameidata *nd, struct path *path) |
Miklos Szeredi | 697f514 | 2012-05-21 17:30:05 +0200 | [diff] [blame] | 1627 | { |
| 1628 | struct dentry *dentry, *parent; |
Miklos Szeredi | 697f514 | 2012-05-21 17:30:05 +0200 | [diff] [blame] | 1629 | |
| 1630 | parent = nd->path.dentry; |
Al Viro | 81e6f52 | 2012-03-30 14:48:04 -0400 | [diff] [blame] | 1631 | BUG_ON(nd->inode != parent->d_inode); |
| 1632 | |
| 1633 | mutex_lock(&parent->d_inode->i_mutex); |
Al Viro | cc2a527 | 2013-01-24 18:19:49 -0500 | [diff] [blame] | 1634 | dentry = __lookup_hash(&nd->last, parent, nd->flags); |
Al Viro | 81e6f52 | 2012-03-30 14:48:04 -0400 | [diff] [blame] | 1635 | mutex_unlock(&parent->d_inode->i_mutex); |
| 1636 | if (IS_ERR(dentry)) |
| 1637 | return PTR_ERR(dentry); |
Miklos Szeredi | 697f514 | 2012-05-21 17:30:05 +0200 | [diff] [blame] | 1638 | path->mnt = nd->path.mnt; |
| 1639 | path->dentry = dentry; |
Al Viro | 8402752 | 2015-04-22 10:30:08 -0400 | [diff] [blame] | 1640 | return follow_managed(path, nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1641 | } |
| 1642 | |
Al Viro | 52094c8 | 2011-02-21 21:34:47 -0500 | [diff] [blame] | 1643 | static inline int may_lookup(struct nameidata *nd) |
| 1644 | { |
| 1645 | if (nd->flags & LOOKUP_RCU) { |
Al Viro | 4ad5abb | 2011-06-20 19:57:03 -0400 | [diff] [blame] | 1646 | int err = inode_permission(nd->inode, MAY_EXEC|MAY_NOT_BLOCK); |
Al Viro | 52094c8 | 2011-02-21 21:34:47 -0500 | [diff] [blame] | 1647 | if (err != -ECHILD) |
| 1648 | return err; |
Al Viro | 6e9918b | 2015-05-05 09:26:05 -0400 | [diff] [blame] | 1649 | if (unlazy_walk(nd, NULL, 0)) |
Al Viro | 52094c8 | 2011-02-21 21:34:47 -0500 | [diff] [blame] | 1650 | return -ECHILD; |
| 1651 | } |
Al Viro | 4ad5abb | 2011-06-20 19:57:03 -0400 | [diff] [blame] | 1652 | return inode_permission(nd->inode, MAY_EXEC); |
Al Viro | 52094c8 | 2011-02-21 21:34:47 -0500 | [diff] [blame] | 1653 | } |
| 1654 | |
Al Viro | 9856fa1 | 2011-03-04 14:22:06 -0500 | [diff] [blame] | 1655 | static inline int handle_dots(struct nameidata *nd, int type) |
| 1656 | { |
| 1657 | if (type == LAST_DOTDOT) { |
| 1658 | if (nd->flags & LOOKUP_RCU) { |
Al Viro | 70291ae | 2015-05-04 07:53:00 -0400 | [diff] [blame] | 1659 | return follow_dotdot_rcu(nd); |
Al Viro | 9856fa1 | 2011-03-04 14:22:06 -0500 | [diff] [blame] | 1660 | } else |
Eric W. Biederman | 397d425 | 2015-08-15 20:27:13 -0500 | [diff] [blame] | 1661 | return follow_dotdot(nd); |
Al Viro | 9856fa1 | 2011-03-04 14:22:06 -0500 | [diff] [blame] | 1662 | } |
| 1663 | return 0; |
| 1664 | } |
| 1665 | |
Al Viro | 181548c | 2015-05-07 19:54:34 -0400 | [diff] [blame] | 1666 | static int pick_link(struct nameidata *nd, struct path *link, |
| 1667 | struct inode *inode, unsigned seq) |
Al Viro | d63ff28 | 2015-05-04 18:13:23 -0400 | [diff] [blame] | 1668 | { |
Al Viro | 626de99 | 2015-05-04 18:26:59 -0400 | [diff] [blame] | 1669 | int error; |
Al Viro | 1cf2665 | 2015-05-06 16:01:56 -0400 | [diff] [blame] | 1670 | struct saved *last; |
NeilBrown | 756daf2 | 2015-03-23 13:37:38 +1100 | [diff] [blame] | 1671 | if (unlikely(nd->total_link_count++ >= MAXSYMLINKS)) { |
Al Viro | 626de99 | 2015-05-04 18:26:59 -0400 | [diff] [blame] | 1672 | path_to_nameidata(link, nd); |
| 1673 | return -ELOOP; |
| 1674 | } |
Al Viro | bc40aee | 2015-05-09 13:04:24 -0400 | [diff] [blame] | 1675 | if (!(nd->flags & LOOKUP_RCU)) { |
Al Viro | 7973387 | 2015-05-09 12:55:43 -0400 | [diff] [blame] | 1676 | if (link->mnt == nd->path.mnt) |
| 1677 | mntget(link->mnt); |
Al Viro | d63ff28 | 2015-05-04 18:13:23 -0400 | [diff] [blame] | 1678 | } |
Al Viro | 626de99 | 2015-05-04 18:26:59 -0400 | [diff] [blame] | 1679 | error = nd_alloc_stack(nd); |
| 1680 | if (unlikely(error)) { |
Al Viro | bc40aee | 2015-05-09 13:04:24 -0400 | [diff] [blame] | 1681 | if (error == -ECHILD) { |
| 1682 | if (unlikely(unlazy_link(nd, link, seq))) |
| 1683 | return -ECHILD; |
| 1684 | error = nd_alloc_stack(nd); |
| 1685 | } |
| 1686 | if (error) { |
| 1687 | path_put(link); |
| 1688 | return error; |
| 1689 | } |
Al Viro | 626de99 | 2015-05-04 18:26:59 -0400 | [diff] [blame] | 1690 | } |
| 1691 | |
Al Viro | ab10492 | 2015-05-10 11:50:01 -0400 | [diff] [blame] | 1692 | last = nd->stack + nd->depth++; |
Al Viro | 1cf2665 | 2015-05-06 16:01:56 -0400 | [diff] [blame] | 1693 | last->link = *link; |
Al Viro | ab10492 | 2015-05-10 11:50:01 -0400 | [diff] [blame] | 1694 | last->cookie = NULL; |
Al Viro | 181548c | 2015-05-07 19:54:34 -0400 | [diff] [blame] | 1695 | last->inode = inode; |
Al Viro | 0450b2d | 2015-05-08 13:23:53 -0400 | [diff] [blame] | 1696 | last->seq = seq; |
Al Viro | d63ff28 | 2015-05-04 18:13:23 -0400 | [diff] [blame] | 1697 | return 1; |
| 1698 | } |
| 1699 | |
Linus Torvalds | 3ddcd05 | 2011-08-06 22:45:50 -0700 | [diff] [blame] | 1700 | /* |
| 1701 | * Do we need to follow links? We _really_ want to be able |
| 1702 | * to do this check without having to look at inode->i_op, |
| 1703 | * so we keep a cache of "no, this doesn't need follow_link" |
| 1704 | * for the common case. |
| 1705 | */ |
Al Viro | 254cf58 | 2015-05-05 09:40:46 -0400 | [diff] [blame] | 1706 | static inline int should_follow_link(struct nameidata *nd, struct path *link, |
Al Viro | 181548c | 2015-05-07 19:54:34 -0400 | [diff] [blame] | 1707 | int follow, |
| 1708 | struct inode *inode, unsigned seq) |
Linus Torvalds | 3ddcd05 | 2011-08-06 22:45:50 -0700 | [diff] [blame] | 1709 | { |
Al Viro | d63ff28 | 2015-05-04 18:13:23 -0400 | [diff] [blame] | 1710 | if (likely(!d_is_symlink(link->dentry))) |
| 1711 | return 0; |
| 1712 | if (!follow) |
| 1713 | return 0; |
Al Viro | 181548c | 2015-05-07 19:54:34 -0400 | [diff] [blame] | 1714 | return pick_link(nd, link, inode, seq); |
Linus Torvalds | 3ddcd05 | 2011-08-06 22:45:50 -0700 | [diff] [blame] | 1715 | } |
| 1716 | |
Al Viro | 4693a54 | 2015-05-04 17:47:11 -0400 | [diff] [blame] | 1717 | enum {WALK_GET = 1, WALK_PUT = 2}; |
| 1718 | |
| 1719 | static int walk_component(struct nameidata *nd, int flags) |
Al Viro | ce57dfc | 2011-03-13 19:58:58 -0400 | [diff] [blame] | 1720 | { |
Al Viro | caa8563 | 2015-04-22 17:52:47 -0400 | [diff] [blame] | 1721 | struct path path; |
Al Viro | ce57dfc | 2011-03-13 19:58:58 -0400 | [diff] [blame] | 1722 | struct inode *inode; |
Al Viro | 254cf58 | 2015-05-05 09:40:46 -0400 | [diff] [blame] | 1723 | unsigned seq; |
Al Viro | ce57dfc | 2011-03-13 19:58:58 -0400 | [diff] [blame] | 1724 | int err; |
| 1725 | /* |
| 1726 | * "." and ".." are special - ".." especially so because it has |
| 1727 | * to be able to know about the current root directory and |
| 1728 | * parent relationships. |
| 1729 | */ |
Al Viro | 4693a54 | 2015-05-04 17:47:11 -0400 | [diff] [blame] | 1730 | if (unlikely(nd->last_type != LAST_NORM)) { |
| 1731 | err = handle_dots(nd, nd->last_type); |
| 1732 | if (flags & WALK_PUT) |
| 1733 | put_link(nd); |
| 1734 | return err; |
| 1735 | } |
Al Viro | 254cf58 | 2015-05-05 09:40:46 -0400 | [diff] [blame] | 1736 | err = lookup_fast(nd, &path, &inode, &seq); |
Al Viro | ce57dfc | 2011-03-13 19:58:58 -0400 | [diff] [blame] | 1737 | if (unlikely(err)) { |
Miklos Szeredi | 697f514 | 2012-05-21 17:30:05 +0200 | [diff] [blame] | 1738 | if (err < 0) |
Al Viro | f0a9ba7 | 2015-05-04 07:59:30 -0400 | [diff] [blame] | 1739 | return err; |
Miklos Szeredi | 697f514 | 2012-05-21 17:30:05 +0200 | [diff] [blame] | 1740 | |
Al Viro | caa8563 | 2015-04-22 17:52:47 -0400 | [diff] [blame] | 1741 | err = lookup_slow(nd, &path); |
Miklos Szeredi | 697f514 | 2012-05-21 17:30:05 +0200 | [diff] [blame] | 1742 | if (err < 0) |
Al Viro | f0a9ba7 | 2015-05-04 07:59:30 -0400 | [diff] [blame] | 1743 | return err; |
Miklos Szeredi | 697f514 | 2012-05-21 17:30:05 +0200 | [diff] [blame] | 1744 | |
David Howells | 63afdfc | 2015-05-06 15:59:00 +0100 | [diff] [blame] | 1745 | inode = d_backing_inode(path.dentry); |
Al Viro | 254cf58 | 2015-05-05 09:40:46 -0400 | [diff] [blame] | 1746 | seq = 0; /* we are already out of RCU mode */ |
Al Viro | 766c4cb | 2015-05-07 19:24:57 -0400 | [diff] [blame] | 1747 | err = -ENOENT; |
Al Viro | caa8563 | 2015-04-22 17:52:47 -0400 | [diff] [blame] | 1748 | if (d_is_negative(path.dentry)) |
Al Viro | 766c4cb | 2015-05-07 19:24:57 -0400 | [diff] [blame] | 1749 | goto out_path_put; |
Al Viro | ce57dfc | 2011-03-13 19:58:58 -0400 | [diff] [blame] | 1750 | } |
Miklos Szeredi | 697f514 | 2012-05-21 17:30:05 +0200 | [diff] [blame] | 1751 | |
Al Viro | 4693a54 | 2015-05-04 17:47:11 -0400 | [diff] [blame] | 1752 | if (flags & WALK_PUT) |
| 1753 | put_link(nd); |
Al Viro | 181548c | 2015-05-07 19:54:34 -0400 | [diff] [blame] | 1754 | err = should_follow_link(nd, &path, flags & WALK_GET, inode, seq); |
Al Viro | d63ff28 | 2015-05-04 18:13:23 -0400 | [diff] [blame] | 1755 | if (unlikely(err)) |
| 1756 | return err; |
Al Viro | caa8563 | 2015-04-22 17:52:47 -0400 | [diff] [blame] | 1757 | path_to_nameidata(&path, nd); |
Al Viro | ce57dfc | 2011-03-13 19:58:58 -0400 | [diff] [blame] | 1758 | nd->inode = inode; |
Al Viro | 254cf58 | 2015-05-05 09:40:46 -0400 | [diff] [blame] | 1759 | nd->seq = seq; |
Al Viro | ce57dfc | 2011-03-13 19:58:58 -0400 | [diff] [blame] | 1760 | return 0; |
Miklos Szeredi | 697f514 | 2012-05-21 17:30:05 +0200 | [diff] [blame] | 1761 | |
| 1762 | out_path_put: |
Al Viro | caa8563 | 2015-04-22 17:52:47 -0400 | [diff] [blame] | 1763 | path_to_nameidata(&path, nd); |
Miklos Szeredi | 697f514 | 2012-05-21 17:30:05 +0200 | [diff] [blame] | 1764 | return err; |
Al Viro | ce57dfc | 2011-03-13 19:58:58 -0400 | [diff] [blame] | 1765 | } |
| 1766 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1767 | /* |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1768 | * We can do the critical dentry name comparison and hashing |
| 1769 | * operations one word at a time, but we are limited to: |
| 1770 | * |
| 1771 | * - Architectures with fast unaligned word accesses. We could |
| 1772 | * do a "get_unaligned()" if this helps and is sufficiently |
| 1773 | * fast. |
| 1774 | * |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1775 | * - non-CONFIG_DEBUG_PAGEALLOC configurations (so that we |
| 1776 | * do not trap on the (extremely unlikely) case of a page |
| 1777 | * crossing operation. |
| 1778 | * |
| 1779 | * - Furthermore, we need an efficient 64-bit compile for the |
| 1780 | * 64-bit case in order to generate the "number of bytes in |
| 1781 | * the final mask". Again, that could be replaced with a |
| 1782 | * efficient population count instruction or similar. |
| 1783 | */ |
| 1784 | #ifdef CONFIG_DCACHE_WORD_ACCESS |
| 1785 | |
Linus Torvalds | f68e556 | 2012-04-06 13:54:56 -0700 | [diff] [blame] | 1786 | #include <asm/word-at-a-time.h> |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1787 | |
Linus Torvalds | f68e556 | 2012-04-06 13:54:56 -0700 | [diff] [blame] | 1788 | #ifdef CONFIG_64BIT |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1789 | |
| 1790 | static inline unsigned int fold_hash(unsigned long hash) |
| 1791 | { |
Linus Torvalds | 99d263d | 2014-09-13 11:30:10 -0700 | [diff] [blame] | 1792 | return hash_64(hash, 32); |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1793 | } |
| 1794 | |
| 1795 | #else /* 32-bit case */ |
| 1796 | |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1797 | #define fold_hash(x) (x) |
| 1798 | |
| 1799 | #endif |
| 1800 | |
| 1801 | unsigned int full_name_hash(const unsigned char *name, unsigned int len) |
| 1802 | { |
| 1803 | unsigned long a, mask; |
| 1804 | unsigned long hash = 0; |
| 1805 | |
| 1806 | for (;;) { |
Linus Torvalds | e419b4c | 2012-05-03 10:16:43 -0700 | [diff] [blame] | 1807 | a = load_unaligned_zeropad(name); |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1808 | if (len < sizeof(unsigned long)) |
| 1809 | break; |
| 1810 | hash += a; |
Al Viro | f132c5b | 2012-03-22 21:59:52 +0000 | [diff] [blame] | 1811 | hash *= 9; |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1812 | name += sizeof(unsigned long); |
| 1813 | len -= sizeof(unsigned long); |
| 1814 | if (!len) |
| 1815 | goto done; |
| 1816 | } |
Will Deacon | a5c21dc | 2013-12-12 17:40:21 +0000 | [diff] [blame] | 1817 | mask = bytemask_from_count(len); |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1818 | hash += mask & a; |
| 1819 | done: |
| 1820 | return fold_hash(hash); |
| 1821 | } |
| 1822 | EXPORT_SYMBOL(full_name_hash); |
| 1823 | |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1824 | /* |
| 1825 | * Calculate the length and hash of the path component, and |
Linus Torvalds | d6bb3e9 | 2014-09-15 10:51:07 -0700 | [diff] [blame] | 1826 | * return the "hash_len" as the result. |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1827 | */ |
Linus Torvalds | d6bb3e9 | 2014-09-15 10:51:07 -0700 | [diff] [blame] | 1828 | static inline u64 hash_name(const char *name) |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1829 | { |
Linus Torvalds | 36126f8 | 2012-05-26 10:43:17 -0700 | [diff] [blame] | 1830 | unsigned long a, b, adata, bdata, mask, hash, len; |
| 1831 | const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS; |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1832 | |
| 1833 | hash = a = 0; |
| 1834 | len = -sizeof(unsigned long); |
| 1835 | do { |
| 1836 | hash = (hash + a) * 9; |
| 1837 | len += sizeof(unsigned long); |
Linus Torvalds | e419b4c | 2012-05-03 10:16:43 -0700 | [diff] [blame] | 1838 | a = load_unaligned_zeropad(name+len); |
Linus Torvalds | 36126f8 | 2012-05-26 10:43:17 -0700 | [diff] [blame] | 1839 | b = a ^ REPEAT_BYTE('/'); |
| 1840 | } while (!(has_zero(a, &adata, &constants) | has_zero(b, &bdata, &constants))); |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1841 | |
Linus Torvalds | 36126f8 | 2012-05-26 10:43:17 -0700 | [diff] [blame] | 1842 | adata = prep_zero_mask(a, adata, &constants); |
| 1843 | bdata = prep_zero_mask(b, bdata, &constants); |
| 1844 | |
| 1845 | mask = create_zero_mask(adata | bdata); |
| 1846 | |
| 1847 | hash += a & zero_bytemask(mask); |
Linus Torvalds | 9226b5b | 2014-09-14 17:28:32 -0700 | [diff] [blame] | 1848 | len += find_zero(mask); |
Linus Torvalds | d6bb3e9 | 2014-09-15 10:51:07 -0700 | [diff] [blame] | 1849 | return hashlen_create(fold_hash(hash), len); |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1850 | } |
| 1851 | |
| 1852 | #else |
| 1853 | |
Linus Torvalds | 0145acc | 2012-03-02 14:32:59 -0800 | [diff] [blame] | 1854 | unsigned int full_name_hash(const unsigned char *name, unsigned int len) |
| 1855 | { |
| 1856 | unsigned long hash = init_name_hash(); |
| 1857 | while (len--) |
| 1858 | hash = partial_name_hash(*name++, hash); |
| 1859 | return end_name_hash(hash); |
| 1860 | } |
Linus Torvalds | ae942ae | 2012-03-02 19:40:57 -0800 | [diff] [blame] | 1861 | EXPORT_SYMBOL(full_name_hash); |
Linus Torvalds | 0145acc | 2012-03-02 14:32:59 -0800 | [diff] [blame] | 1862 | |
Linus Torvalds | 3ddcd05 | 2011-08-06 22:45:50 -0700 | [diff] [blame] | 1863 | /* |
Linus Torvalds | 200e9ef | 2012-03-02 14:49:24 -0800 | [diff] [blame] | 1864 | * We know there's a real path component here of at least |
| 1865 | * one character. |
| 1866 | */ |
Linus Torvalds | d6bb3e9 | 2014-09-15 10:51:07 -0700 | [diff] [blame] | 1867 | static inline u64 hash_name(const char *name) |
Linus Torvalds | 200e9ef | 2012-03-02 14:49:24 -0800 | [diff] [blame] | 1868 | { |
| 1869 | unsigned long hash = init_name_hash(); |
| 1870 | unsigned long len = 0, c; |
| 1871 | |
| 1872 | c = (unsigned char)*name; |
| 1873 | do { |
| 1874 | len++; |
| 1875 | hash = partial_name_hash(c, hash); |
| 1876 | c = (unsigned char)name[len]; |
| 1877 | } while (c && c != '/'); |
Linus Torvalds | d6bb3e9 | 2014-09-15 10:51:07 -0700 | [diff] [blame] | 1878 | return hashlen_create(end_name_hash(hash), len); |
Linus Torvalds | 200e9ef | 2012-03-02 14:49:24 -0800 | [diff] [blame] | 1879 | } |
| 1880 | |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1881 | #endif |
| 1882 | |
Linus Torvalds | 200e9ef | 2012-03-02 14:49:24 -0800 | [diff] [blame] | 1883 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1884 | * Name resolution. |
Prasanna Meda | ea3834d | 2005-04-29 16:00:17 +0100 | [diff] [blame] | 1885 | * This is the basic name resolution function, turning a pathname into |
| 1886 | * the final dentry. We expect 'base' to be positive and a directory. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1887 | * |
Prasanna Meda | ea3834d | 2005-04-29 16:00:17 +0100 | [diff] [blame] | 1888 | * Returns 0 and nd will have valid dentry and mnt on success. |
| 1889 | * Returns error and drops reference to input namei data on failure. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1890 | */ |
Al Viro | 6de88d7 | 2009-08-09 01:41:57 +0400 | [diff] [blame] | 1891 | static int link_path_walk(const char *name, struct nameidata *nd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1892 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1893 | int err; |
Al Viro | 32cd746 | 2015-04-18 20:30:49 -0400 | [diff] [blame] | 1894 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1895 | while (*name=='/') |
| 1896 | name++; |
| 1897 | if (!*name) |
Al Viro | 9e18f10 | 2015-04-18 20:44:34 -0400 | [diff] [blame] | 1898 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1899 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1900 | /* At this point we know we have a real path component. */ |
| 1901 | for(;;) { |
Linus Torvalds | d6bb3e9 | 2014-09-15 10:51:07 -0700 | [diff] [blame] | 1902 | u64 hash_len; |
Al Viro | fe479a5 | 2011-02-22 15:10:03 -0500 | [diff] [blame] | 1903 | int type; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1904 | |
Al Viro | 52094c8 | 2011-02-21 21:34:47 -0500 | [diff] [blame] | 1905 | err = may_lookup(nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1906 | if (err) |
Al Viro | 3595e23 | 2015-05-09 16:54:45 -0400 | [diff] [blame] | 1907 | return err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1908 | |
Linus Torvalds | d6bb3e9 | 2014-09-15 10:51:07 -0700 | [diff] [blame] | 1909 | hash_len = hash_name(name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1910 | |
Al Viro | fe479a5 | 2011-02-22 15:10:03 -0500 | [diff] [blame] | 1911 | type = LAST_NORM; |
Linus Torvalds | d6bb3e9 | 2014-09-15 10:51:07 -0700 | [diff] [blame] | 1912 | if (name[0] == '.') switch (hashlen_len(hash_len)) { |
Al Viro | fe479a5 | 2011-02-22 15:10:03 -0500 | [diff] [blame] | 1913 | case 2: |
Linus Torvalds | 200e9ef | 2012-03-02 14:49:24 -0800 | [diff] [blame] | 1914 | if (name[1] == '.') { |
Al Viro | fe479a5 | 2011-02-22 15:10:03 -0500 | [diff] [blame] | 1915 | type = LAST_DOTDOT; |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 1916 | nd->flags |= LOOKUP_JUMPED; |
| 1917 | } |
Al Viro | fe479a5 | 2011-02-22 15:10:03 -0500 | [diff] [blame] | 1918 | break; |
| 1919 | case 1: |
| 1920 | type = LAST_DOT; |
| 1921 | } |
Al Viro | 5a202bc | 2011-03-08 14:17:44 -0500 | [diff] [blame] | 1922 | if (likely(type == LAST_NORM)) { |
| 1923 | struct dentry *parent = nd->path.dentry; |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 1924 | nd->flags &= ~LOOKUP_JUMPED; |
Al Viro | 5a202bc | 2011-03-08 14:17:44 -0500 | [diff] [blame] | 1925 | if (unlikely(parent->d_flags & DCACHE_OP_HASH)) { |
James Hogan | a060dc5 | 2014-09-16 13:07:35 +0100 | [diff] [blame] | 1926 | struct qstr this = { { .hash_len = hash_len }, .name = name }; |
Linus Torvalds | da53be1 | 2013-05-21 15:22:44 -0700 | [diff] [blame] | 1927 | err = parent->d_op->d_hash(parent, &this); |
Al Viro | 5a202bc | 2011-03-08 14:17:44 -0500 | [diff] [blame] | 1928 | if (err < 0) |
Al Viro | 3595e23 | 2015-05-09 16:54:45 -0400 | [diff] [blame] | 1929 | return err; |
Linus Torvalds | d6bb3e9 | 2014-09-15 10:51:07 -0700 | [diff] [blame] | 1930 | hash_len = this.hash_len; |
| 1931 | name = this.name; |
Al Viro | 5a202bc | 2011-03-08 14:17:44 -0500 | [diff] [blame] | 1932 | } |
| 1933 | } |
Al Viro | fe479a5 | 2011-02-22 15:10:03 -0500 | [diff] [blame] | 1934 | |
Linus Torvalds | d6bb3e9 | 2014-09-15 10:51:07 -0700 | [diff] [blame] | 1935 | nd->last.hash_len = hash_len; |
| 1936 | nd->last.name = name; |
Al Viro | 5f4a6a6 | 2013-01-24 18:04:22 -0500 | [diff] [blame] | 1937 | nd->last_type = type; |
| 1938 | |
Linus Torvalds | d6bb3e9 | 2014-09-15 10:51:07 -0700 | [diff] [blame] | 1939 | name += hashlen_len(hash_len); |
| 1940 | if (!*name) |
Al Viro | bdf6cbf | 2015-04-18 20:21:40 -0400 | [diff] [blame] | 1941 | goto OK; |
Linus Torvalds | 200e9ef | 2012-03-02 14:49:24 -0800 | [diff] [blame] | 1942 | /* |
| 1943 | * If it wasn't NUL, we know it was '/'. Skip that |
| 1944 | * slash, and continue until no more slashes. |
| 1945 | */ |
| 1946 | do { |
Linus Torvalds | d6bb3e9 | 2014-09-15 10:51:07 -0700 | [diff] [blame] | 1947 | name++; |
| 1948 | } while (unlikely(*name == '/')); |
Al Viro | 8620c23 | 2015-05-04 08:58:35 -0400 | [diff] [blame] | 1949 | if (unlikely(!*name)) { |
| 1950 | OK: |
Al Viro | 368ee9b | 2015-05-08 17:19:59 -0400 | [diff] [blame] | 1951 | /* pathname body, done */ |
Al Viro | 8620c23 | 2015-05-04 08:58:35 -0400 | [diff] [blame] | 1952 | if (!nd->depth) |
| 1953 | return 0; |
| 1954 | name = nd->stack[nd->depth - 1].name; |
Al Viro | 368ee9b | 2015-05-08 17:19:59 -0400 | [diff] [blame] | 1955 | /* trailing symlink, done */ |
Al Viro | 8620c23 | 2015-05-04 08:58:35 -0400 | [diff] [blame] | 1956 | if (!name) |
| 1957 | return 0; |
| 1958 | /* last component of nested symlink */ |
Al Viro | 4693a54 | 2015-05-04 17:47:11 -0400 | [diff] [blame] | 1959 | err = walk_component(nd, WALK_GET | WALK_PUT); |
Al Viro | 8620c23 | 2015-05-04 08:58:35 -0400 | [diff] [blame] | 1960 | } else { |
Al Viro | 4693a54 | 2015-05-04 17:47:11 -0400 | [diff] [blame] | 1961 | err = walk_component(nd, WALK_GET); |
Al Viro | 8620c23 | 2015-05-04 08:58:35 -0400 | [diff] [blame] | 1962 | } |
Al Viro | ce57dfc | 2011-03-13 19:58:58 -0400 | [diff] [blame] | 1963 | if (err < 0) |
Al Viro | 3595e23 | 2015-05-09 16:54:45 -0400 | [diff] [blame] | 1964 | return err; |
Al Viro | fe479a5 | 2011-02-22 15:10:03 -0500 | [diff] [blame] | 1965 | |
Al Viro | ce57dfc | 2011-03-13 19:58:58 -0400 | [diff] [blame] | 1966 | if (err) { |
Al Viro | 626de99 | 2015-05-04 18:26:59 -0400 | [diff] [blame] | 1967 | const char *s = get_link(nd); |
Al Viro | 5a46027 | 2015-04-17 23:44:45 -0400 | [diff] [blame] | 1968 | |
Viresh Kumar | a1c8368 | 2015-08-12 15:59:44 +0530 | [diff] [blame] | 1969 | if (IS_ERR(s)) |
Al Viro | 3595e23 | 2015-05-09 16:54:45 -0400 | [diff] [blame] | 1970 | return PTR_ERR(s); |
Al Viro | d40bcc0 | 2015-04-18 20:03:03 -0400 | [diff] [blame] | 1971 | err = 0; |
| 1972 | if (unlikely(!s)) { |
| 1973 | /* jumped */ |
Al Viro | b9ff442 | 2015-05-02 20:19:23 -0400 | [diff] [blame] | 1974 | put_link(nd); |
Al Viro | d40bcc0 | 2015-04-18 20:03:03 -0400 | [diff] [blame] | 1975 | } else { |
Al Viro | fab51e8 | 2015-05-10 11:01:00 -0400 | [diff] [blame] | 1976 | nd->stack[nd->depth - 1].name = name; |
| 1977 | name = s; |
| 1978 | continue; |
Al Viro | d40bcc0 | 2015-04-18 20:03:03 -0400 | [diff] [blame] | 1979 | } |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1980 | } |
Al Viro | 97242f9 | 2015-08-01 19:59:28 -0400 | [diff] [blame] | 1981 | if (unlikely(!d_can_lookup(nd->path.dentry))) { |
| 1982 | if (nd->flags & LOOKUP_RCU) { |
| 1983 | if (unlazy_walk(nd, NULL, 0)) |
| 1984 | return -ECHILD; |
| 1985 | } |
Al Viro | 3595e23 | 2015-05-09 16:54:45 -0400 | [diff] [blame] | 1986 | return -ENOTDIR; |
Al Viro | 97242f9 | 2015-08-01 19:59:28 -0400 | [diff] [blame] | 1987 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1988 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1989 | } |
| 1990 | |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 1991 | static const char *path_init(struct nameidata *nd, unsigned flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1992 | { |
Prasanna Meda | ea3834d | 2005-04-29 16:00:17 +0100 | [diff] [blame] | 1993 | int retval = 0; |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 1994 | const char *s = nd->name->name; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1995 | |
| 1996 | nd->last_type = LAST_ROOT; /* if there are only slashes... */ |
Al Viro | 980f3ea | 2014-11-20 14:20:24 -0500 | [diff] [blame] | 1997 | nd->flags = flags | LOOKUP_JUMPED | LOOKUP_PARENT; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1998 | nd->depth = 0; |
Al Viro | 368ee9b | 2015-05-08 17:19:59 -0400 | [diff] [blame] | 1999 | nd->total_link_count = 0; |
Al Viro | 5b6ca02 | 2011-03-09 23:04:47 -0500 | [diff] [blame] | 2000 | if (flags & LOOKUP_ROOT) { |
David Howells | b18825a | 2013-09-12 19:22:53 +0100 | [diff] [blame] | 2001 | struct dentry *root = nd->root.dentry; |
| 2002 | struct inode *inode = root->d_inode; |
Al Viro | fd2f7cb | 2015-02-22 20:07:13 -0500 | [diff] [blame] | 2003 | if (*s) { |
Miklos Szeredi | 44b1d53 | 2014-04-01 17:08:41 +0200 | [diff] [blame] | 2004 | if (!d_can_lookup(root)) |
Al Viro | 368ee9b | 2015-05-08 17:19:59 -0400 | [diff] [blame] | 2005 | return ERR_PTR(-ENOTDIR); |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 2006 | retval = inode_permission(inode, MAY_EXEC); |
| 2007 | if (retval) |
Al Viro | 368ee9b | 2015-05-08 17:19:59 -0400 | [diff] [blame] | 2008 | return ERR_PTR(retval); |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 2009 | } |
Al Viro | 5b6ca02 | 2011-03-09 23:04:47 -0500 | [diff] [blame] | 2010 | nd->path = nd->root; |
| 2011 | nd->inode = inode; |
| 2012 | if (flags & LOOKUP_RCU) { |
Al Viro | 8b61e74 | 2013-11-08 12:45:01 -0500 | [diff] [blame] | 2013 | rcu_read_lock(); |
Al Viro | 5b6ca02 | 2011-03-09 23:04:47 -0500 | [diff] [blame] | 2014 | nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq); |
Al Viro | 8f47a016 | 2015-05-09 19:02:01 -0400 | [diff] [blame] | 2015 | nd->root_seq = nd->seq; |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 2016 | nd->m_seq = read_seqbegin(&mount_lock); |
Al Viro | 5b6ca02 | 2011-03-09 23:04:47 -0500 | [diff] [blame] | 2017 | } else { |
| 2018 | path_get(&nd->path); |
| 2019 | } |
Al Viro | 368ee9b | 2015-05-08 17:19:59 -0400 | [diff] [blame] | 2020 | return s; |
Al Viro | 5b6ca02 | 2011-03-09 23:04:47 -0500 | [diff] [blame] | 2021 | } |
| 2022 | |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 2023 | nd->root.mnt = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2024 | |
Al Viro | 48a066e | 2013-09-29 22:06:07 -0400 | [diff] [blame] | 2025 | nd->m_seq = read_seqbegin(&mount_lock); |
Al Viro | fd2f7cb | 2015-02-22 20:07:13 -0500 | [diff] [blame] | 2026 | if (*s == '/') { |
Al Viro | e41f7d4 | 2011-02-22 14:02:58 -0500 | [diff] [blame] | 2027 | if (flags & LOOKUP_RCU) { |
Al Viro | 8b61e74 | 2013-11-08 12:45:01 -0500 | [diff] [blame] | 2028 | rcu_read_lock(); |
Al Viro | 06d7137 | 2015-06-29 12:07:04 -0400 | [diff] [blame] | 2029 | set_root_rcu(nd); |
| 2030 | nd->seq = nd->root_seq; |
Al Viro | e41f7d4 | 2011-02-22 14:02:58 -0500 | [diff] [blame] | 2031 | } else { |
| 2032 | set_root(nd); |
| 2033 | path_get(&nd->root); |
| 2034 | } |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 2035 | nd->path = nd->root; |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 2036 | } else if (nd->dfd == AT_FDCWD) { |
Al Viro | e41f7d4 | 2011-02-22 14:02:58 -0500 | [diff] [blame] | 2037 | if (flags & LOOKUP_RCU) { |
| 2038 | struct fs_struct *fs = current->fs; |
| 2039 | unsigned seq; |
| 2040 | |
Al Viro | 8b61e74 | 2013-11-08 12:45:01 -0500 | [diff] [blame] | 2041 | rcu_read_lock(); |
Al Viro | e41f7d4 | 2011-02-22 14:02:58 -0500 | [diff] [blame] | 2042 | |
| 2043 | do { |
| 2044 | seq = read_seqcount_begin(&fs->seq); |
| 2045 | nd->path = fs->pwd; |
| 2046 | nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq); |
| 2047 | } while (read_seqcount_retry(&fs->seq, seq)); |
| 2048 | } else { |
| 2049 | get_fs_pwd(current->fs, &nd->path); |
| 2050 | } |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2051 | } else { |
Jeff Layton | 582aa64 | 2012-12-11 08:56:16 -0500 | [diff] [blame] | 2052 | /* Caller must check execute permissions on the starting path component */ |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 2053 | struct fd f = fdget_raw(nd->dfd); |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2054 | struct dentry *dentry; |
| 2055 | |
Al Viro | 2903ff0 | 2012-08-28 12:52:22 -0400 | [diff] [blame] | 2056 | if (!f.file) |
Al Viro | 368ee9b | 2015-05-08 17:19:59 -0400 | [diff] [blame] | 2057 | return ERR_PTR(-EBADF); |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2058 | |
Al Viro | 2903ff0 | 2012-08-28 12:52:22 -0400 | [diff] [blame] | 2059 | dentry = f.file->f_path.dentry; |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2060 | |
Al Viro | fd2f7cb | 2015-02-22 20:07:13 -0500 | [diff] [blame] | 2061 | if (*s) { |
Miklos Szeredi | 44b1d53 | 2014-04-01 17:08:41 +0200 | [diff] [blame] | 2062 | if (!d_can_lookup(dentry)) { |
Al Viro | 2903ff0 | 2012-08-28 12:52:22 -0400 | [diff] [blame] | 2063 | fdput(f); |
Al Viro | 368ee9b | 2015-05-08 17:19:59 -0400 | [diff] [blame] | 2064 | return ERR_PTR(-ENOTDIR); |
Al Viro | 2903ff0 | 2012-08-28 12:52:22 -0400 | [diff] [blame] | 2065 | } |
Al Viro | f52e0c1 | 2011-03-14 18:56:51 -0400 | [diff] [blame] | 2066 | } |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2067 | |
Al Viro | 2903ff0 | 2012-08-28 12:52:22 -0400 | [diff] [blame] | 2068 | nd->path = f.file->f_path; |
Al Viro | e41f7d4 | 2011-02-22 14:02:58 -0500 | [diff] [blame] | 2069 | if (flags & LOOKUP_RCU) { |
Al Viro | 8b61e74 | 2013-11-08 12:45:01 -0500 | [diff] [blame] | 2070 | rcu_read_lock(); |
Al Viro | 34a26b9 | 2015-05-11 08:05:05 -0400 | [diff] [blame] | 2071 | nd->inode = nd->path.dentry->d_inode; |
| 2072 | nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq); |
Al Viro | e41f7d4 | 2011-02-22 14:02:58 -0500 | [diff] [blame] | 2073 | } else { |
Al Viro | 2903ff0 | 2012-08-28 12:52:22 -0400 | [diff] [blame] | 2074 | path_get(&nd->path); |
Al Viro | 34a26b9 | 2015-05-11 08:05:05 -0400 | [diff] [blame] | 2075 | nd->inode = nd->path.dentry->d_inode; |
Al Viro | e41f7d4 | 2011-02-22 14:02:58 -0500 | [diff] [blame] | 2076 | } |
Al Viro | 34a26b9 | 2015-05-11 08:05:05 -0400 | [diff] [blame] | 2077 | fdput(f); |
Al Viro | 368ee9b | 2015-05-08 17:19:59 -0400 | [diff] [blame] | 2078 | return s; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2079 | } |
Al Viro | e41f7d4 | 2011-02-22 14:02:58 -0500 | [diff] [blame] | 2080 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2081 | nd->inode = nd->path.dentry->d_inode; |
Al Viro | 4023bfc | 2014-09-13 21:59:43 -0400 | [diff] [blame] | 2082 | if (!(flags & LOOKUP_RCU)) |
Al Viro | 368ee9b | 2015-05-08 17:19:59 -0400 | [diff] [blame] | 2083 | return s; |
Al Viro | 4023bfc | 2014-09-13 21:59:43 -0400 | [diff] [blame] | 2084 | if (likely(!read_seqcount_retry(&nd->path.dentry->d_seq, nd->seq))) |
Al Viro | 368ee9b | 2015-05-08 17:19:59 -0400 | [diff] [blame] | 2085 | return s; |
Al Viro | 4023bfc | 2014-09-13 21:59:43 -0400 | [diff] [blame] | 2086 | if (!(nd->flags & LOOKUP_ROOT)) |
| 2087 | nd->root.mnt = NULL; |
| 2088 | rcu_read_unlock(); |
Al Viro | 368ee9b | 2015-05-08 17:19:59 -0400 | [diff] [blame] | 2089 | return ERR_PTR(-ECHILD); |
Al Viro | 9b4a9b1 | 2009-04-07 11:44:16 -0400 | [diff] [blame] | 2090 | } |
| 2091 | |
Al Viro | 3bdba28 | 2015-05-08 17:37:07 -0400 | [diff] [blame] | 2092 | static const char *trailing_symlink(struct nameidata *nd) |
Al Viro | 95fa25d | 2015-04-22 13:46:57 -0400 | [diff] [blame] | 2093 | { |
| 2094 | const char *s; |
Al Viro | fec2fa2 | 2015-05-06 15:58:18 -0400 | [diff] [blame] | 2095 | int error = may_follow_link(nd); |
Al Viro | deb106c | 2015-05-08 18:05:21 -0400 | [diff] [blame] | 2096 | if (unlikely(error)) |
Al Viro | 3bdba28 | 2015-05-08 17:37:07 -0400 | [diff] [blame] | 2097 | return ERR_PTR(error); |
Al Viro | 95fa25d | 2015-04-22 13:46:57 -0400 | [diff] [blame] | 2098 | nd->flags |= LOOKUP_PARENT; |
Al Viro | fab51e8 | 2015-05-10 11:01:00 -0400 | [diff] [blame] | 2099 | nd->stack[0].name = NULL; |
Al Viro | 3b2e7f7 | 2015-04-19 00:53:50 -0400 | [diff] [blame] | 2100 | s = get_link(nd); |
Al Viro | deb106c | 2015-05-08 18:05:21 -0400 | [diff] [blame] | 2101 | return s ? s : ""; |
Al Viro | 95fa25d | 2015-04-22 13:46:57 -0400 | [diff] [blame] | 2102 | } |
| 2103 | |
Al Viro | caa8563 | 2015-04-22 17:52:47 -0400 | [diff] [blame] | 2104 | static inline int lookup_last(struct nameidata *nd) |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 2105 | { |
| 2106 | if (nd->last_type == LAST_NORM && nd->last.name[nd->last.len]) |
| 2107 | nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY; |
| 2108 | |
| 2109 | nd->flags &= ~LOOKUP_PARENT; |
Al Viro | deb106c | 2015-05-08 18:05:21 -0400 | [diff] [blame] | 2110 | return walk_component(nd, |
Al Viro | 4693a54 | 2015-05-04 17:47:11 -0400 | [diff] [blame] | 2111 | nd->flags & LOOKUP_FOLLOW |
| 2112 | ? nd->depth |
| 2113 | ? WALK_PUT | WALK_GET |
| 2114 | : WALK_GET |
| 2115 | : 0); |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 2116 | } |
| 2117 | |
Al Viro | 9b4a9b1 | 2009-04-07 11:44:16 -0400 | [diff] [blame] | 2118 | /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */ |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 2119 | static int path_lookupat(struct nameidata *nd, unsigned flags, struct path *path) |
Al Viro | 9b4a9b1 | 2009-04-07 11:44:16 -0400 | [diff] [blame] | 2120 | { |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 2121 | const char *s = path_init(nd, flags); |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 2122 | int err; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2123 | |
Al Viro | 368ee9b | 2015-05-08 17:19:59 -0400 | [diff] [blame] | 2124 | if (IS_ERR(s)) |
| 2125 | return PTR_ERR(s); |
Al Viro | 3bdba28 | 2015-05-08 17:37:07 -0400 | [diff] [blame] | 2126 | while (!(err = link_path_walk(s, nd)) |
| 2127 | && ((err = lookup_last(nd)) > 0)) { |
| 2128 | s = trailing_symlink(nd); |
| 2129 | if (IS_ERR(s)) { |
| 2130 | err = PTR_ERR(s); |
| 2131 | break; |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 2132 | } |
| 2133 | } |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 2134 | if (!err) |
| 2135 | err = complete_walk(nd); |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 2136 | |
Al Viro | deb106c | 2015-05-08 18:05:21 -0400 | [diff] [blame] | 2137 | if (!err && nd->flags & LOOKUP_DIRECTORY) |
| 2138 | if (!d_can_lookup(nd->path.dentry)) |
Al Viro | bd23a53 | 2011-03-23 09:56:30 -0400 | [diff] [blame] | 2139 | err = -ENOTDIR; |
Al Viro | 625b6d1 | 2015-05-12 16:36:12 -0400 | [diff] [blame] | 2140 | if (!err) { |
| 2141 | *path = nd->path; |
| 2142 | nd->path.mnt = NULL; |
| 2143 | nd->path.dentry = NULL; |
| 2144 | } |
| 2145 | terminate_walk(nd); |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 2146 | return err; |
Al Viro | ee0827c | 2011-02-21 23:38:09 -0500 | [diff] [blame] | 2147 | } |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2148 | |
Al Viro | 625b6d1 | 2015-05-12 16:36:12 -0400 | [diff] [blame] | 2149 | static int filename_lookup(int dfd, struct filename *name, unsigned flags, |
Al Viro | 9ad1aaa | 2015-05-12 16:44:39 -0400 | [diff] [blame] | 2150 | struct path *path, struct path *root) |
Jeff Layton | 873f1ee | 2012-10-10 15:25:29 -0400 | [diff] [blame] | 2151 | { |
Al Viro | 894bc8c | 2015-05-02 07:16:16 -0400 | [diff] [blame] | 2152 | int retval; |
Al Viro | 9883d18 | 2015-05-13 07:28:08 -0400 | [diff] [blame] | 2153 | struct nameidata nd; |
Al Viro | abc9f5b | 2015-05-12 16:53:42 -0400 | [diff] [blame] | 2154 | if (IS_ERR(name)) |
| 2155 | return PTR_ERR(name); |
Al Viro | 9ad1aaa | 2015-05-12 16:44:39 -0400 | [diff] [blame] | 2156 | if (unlikely(root)) { |
| 2157 | nd.root = *root; |
| 2158 | flags |= LOOKUP_ROOT; |
| 2159 | } |
Al Viro | 9883d18 | 2015-05-13 07:28:08 -0400 | [diff] [blame] | 2160 | set_nameidata(&nd, dfd, name); |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 2161 | retval = path_lookupat(&nd, flags | LOOKUP_RCU, path); |
Jeff Layton | 873f1ee | 2012-10-10 15:25:29 -0400 | [diff] [blame] | 2162 | if (unlikely(retval == -ECHILD)) |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 2163 | retval = path_lookupat(&nd, flags, path); |
Jeff Layton | 873f1ee | 2012-10-10 15:25:29 -0400 | [diff] [blame] | 2164 | if (unlikely(retval == -ESTALE)) |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 2165 | retval = path_lookupat(&nd, flags | LOOKUP_REVAL, path); |
Jeff Layton | 873f1ee | 2012-10-10 15:25:29 -0400 | [diff] [blame] | 2166 | |
| 2167 | if (likely(!retval)) |
Al Viro | 625b6d1 | 2015-05-12 16:36:12 -0400 | [diff] [blame] | 2168 | audit_inode(name, path->dentry, flags & LOOKUP_PARENT); |
Al Viro | 9883d18 | 2015-05-13 07:28:08 -0400 | [diff] [blame] | 2169 | restore_nameidata(); |
Al Viro | e4bd1c1 | 2015-05-12 16:40:39 -0400 | [diff] [blame] | 2170 | putname(name); |
Jeff Layton | 873f1ee | 2012-10-10 15:25:29 -0400 | [diff] [blame] | 2171 | return retval; |
| 2172 | } |
| 2173 | |
Al Viro | 8bcb77f | 2015-05-08 16:59:20 -0400 | [diff] [blame] | 2174 | /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */ |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 2175 | static int path_parentat(struct nameidata *nd, unsigned flags, |
Al Viro | 391172c | 2015-05-09 11:19:16 -0400 | [diff] [blame] | 2176 | struct path *parent) |
Al Viro | 8bcb77f | 2015-05-08 16:59:20 -0400 | [diff] [blame] | 2177 | { |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 2178 | const char *s = path_init(nd, flags); |
Al Viro | 368ee9b | 2015-05-08 17:19:59 -0400 | [diff] [blame] | 2179 | int err; |
| 2180 | if (IS_ERR(s)) |
| 2181 | return PTR_ERR(s); |
| 2182 | err = link_path_walk(s, nd); |
Al Viro | 8bcb77f | 2015-05-08 16:59:20 -0400 | [diff] [blame] | 2183 | if (!err) |
| 2184 | err = complete_walk(nd); |
Al Viro | 391172c | 2015-05-09 11:19:16 -0400 | [diff] [blame] | 2185 | if (!err) { |
| 2186 | *parent = nd->path; |
| 2187 | nd->path.mnt = NULL; |
| 2188 | nd->path.dentry = NULL; |
| 2189 | } |
| 2190 | terminate_walk(nd); |
Al Viro | 8bcb77f | 2015-05-08 16:59:20 -0400 | [diff] [blame] | 2191 | return err; |
| 2192 | } |
| 2193 | |
Al Viro | 5c31b6c | 2015-05-12 17:32:54 -0400 | [diff] [blame] | 2194 | static struct filename *filename_parentat(int dfd, struct filename *name, |
Al Viro | 391172c | 2015-05-09 11:19:16 -0400 | [diff] [blame] | 2195 | unsigned int flags, struct path *parent, |
| 2196 | struct qstr *last, int *type) |
Al Viro | 8bcb77f | 2015-05-08 16:59:20 -0400 | [diff] [blame] | 2197 | { |
| 2198 | int retval; |
Al Viro | 9883d18 | 2015-05-13 07:28:08 -0400 | [diff] [blame] | 2199 | struct nameidata nd; |
Al Viro | 8bcb77f | 2015-05-08 16:59:20 -0400 | [diff] [blame] | 2200 | |
Al Viro | 5c31b6c | 2015-05-12 17:32:54 -0400 | [diff] [blame] | 2201 | if (IS_ERR(name)) |
| 2202 | return name; |
Al Viro | 9883d18 | 2015-05-13 07:28:08 -0400 | [diff] [blame] | 2203 | set_nameidata(&nd, dfd, name); |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 2204 | retval = path_parentat(&nd, flags | LOOKUP_RCU, parent); |
Al Viro | 8bcb77f | 2015-05-08 16:59:20 -0400 | [diff] [blame] | 2205 | if (unlikely(retval == -ECHILD)) |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 2206 | retval = path_parentat(&nd, flags, parent); |
Al Viro | 8bcb77f | 2015-05-08 16:59:20 -0400 | [diff] [blame] | 2207 | if (unlikely(retval == -ESTALE)) |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 2208 | retval = path_parentat(&nd, flags | LOOKUP_REVAL, parent); |
Al Viro | 391172c | 2015-05-09 11:19:16 -0400 | [diff] [blame] | 2209 | if (likely(!retval)) { |
| 2210 | *last = nd.last; |
| 2211 | *type = nd.last_type; |
| 2212 | audit_inode(name, parent->dentry, LOOKUP_PARENT); |
Al Viro | 5c31b6c | 2015-05-12 17:32:54 -0400 | [diff] [blame] | 2213 | } else { |
| 2214 | putname(name); |
| 2215 | name = ERR_PTR(retval); |
Al Viro | 391172c | 2015-05-09 11:19:16 -0400 | [diff] [blame] | 2216 | } |
Al Viro | 9883d18 | 2015-05-13 07:28:08 -0400 | [diff] [blame] | 2217 | restore_nameidata(); |
Al Viro | 5c31b6c | 2015-05-12 17:32:54 -0400 | [diff] [blame] | 2218 | return name; |
Al Viro | 8bcb77f | 2015-05-08 16:59:20 -0400 | [diff] [blame] | 2219 | } |
| 2220 | |
Al Viro | 79714f7 | 2012-06-15 03:01:42 +0400 | [diff] [blame] | 2221 | /* does lookup, returns the object with parent locked */ |
| 2222 | struct dentry *kern_path_locked(const char *name, struct path *path) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2223 | { |
Al Viro | 5c31b6c | 2015-05-12 17:32:54 -0400 | [diff] [blame] | 2224 | struct filename *filename; |
| 2225 | struct dentry *d; |
Al Viro | 391172c | 2015-05-09 11:19:16 -0400 | [diff] [blame] | 2226 | struct qstr last; |
| 2227 | int type; |
Paul Moore | 5168910 | 2015-01-22 00:00:03 -0500 | [diff] [blame] | 2228 | |
Al Viro | 5c31b6c | 2015-05-12 17:32:54 -0400 | [diff] [blame] | 2229 | filename = filename_parentat(AT_FDCWD, getname_kernel(name), 0, path, |
| 2230 | &last, &type); |
Paul Moore | 5168910 | 2015-01-22 00:00:03 -0500 | [diff] [blame] | 2231 | if (IS_ERR(filename)) |
| 2232 | return ERR_CAST(filename); |
Al Viro | 5c31b6c | 2015-05-12 17:32:54 -0400 | [diff] [blame] | 2233 | if (unlikely(type != LAST_NORM)) { |
Al Viro | 391172c | 2015-05-09 11:19:16 -0400 | [diff] [blame] | 2234 | path_put(path); |
Al Viro | 5c31b6c | 2015-05-12 17:32:54 -0400 | [diff] [blame] | 2235 | putname(filename); |
| 2236 | return ERR_PTR(-EINVAL); |
Al Viro | 79714f7 | 2012-06-15 03:01:42 +0400 | [diff] [blame] | 2237 | } |
Al Viro | 391172c | 2015-05-09 11:19:16 -0400 | [diff] [blame] | 2238 | mutex_lock_nested(&path->dentry->d_inode->i_mutex, I_MUTEX_PARENT); |
| 2239 | d = __lookup_hash(&last, path->dentry, 0); |
Al Viro | 79714f7 | 2012-06-15 03:01:42 +0400 | [diff] [blame] | 2240 | if (IS_ERR(d)) { |
Al Viro | 391172c | 2015-05-09 11:19:16 -0400 | [diff] [blame] | 2241 | mutex_unlock(&path->dentry->d_inode->i_mutex); |
| 2242 | path_put(path); |
Al Viro | 79714f7 | 2012-06-15 03:01:42 +0400 | [diff] [blame] | 2243 | } |
Paul Moore | 5168910 | 2015-01-22 00:00:03 -0500 | [diff] [blame] | 2244 | putname(filename); |
Al Viro | 79714f7 | 2012-06-15 03:01:42 +0400 | [diff] [blame] | 2245 | return d; |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2246 | } |
| 2247 | |
Al Viro | d181146 | 2008-08-02 00:49:18 -0400 | [diff] [blame] | 2248 | int kern_path(const char *name, unsigned int flags, struct path *path) |
| 2249 | { |
Al Viro | abc9f5b | 2015-05-12 16:53:42 -0400 | [diff] [blame] | 2250 | return filename_lookup(AT_FDCWD, getname_kernel(name), |
| 2251 | flags, path, NULL); |
Al Viro | d181146 | 2008-08-02 00:49:18 -0400 | [diff] [blame] | 2252 | } |
Al Viro | 4d35950 | 2014-03-14 12:20:17 -0400 | [diff] [blame] | 2253 | EXPORT_SYMBOL(kern_path); |
Al Viro | d181146 | 2008-08-02 00:49:18 -0400 | [diff] [blame] | 2254 | |
Josef 'Jeff' Sipek | 16f1820 | 2007-07-19 01:48:18 -0700 | [diff] [blame] | 2255 | /** |
| 2256 | * vfs_path_lookup - lookup a file path relative to a dentry-vfsmount pair |
| 2257 | * @dentry: pointer to dentry of the base directory |
| 2258 | * @mnt: pointer to vfs mount of the base directory |
| 2259 | * @name: pointer to file name |
| 2260 | * @flags: lookup flags |
Al Viro | e0a0124 | 2011-06-27 17:00:37 -0400 | [diff] [blame] | 2261 | * @path: pointer to struct path to fill |
Josef 'Jeff' Sipek | 16f1820 | 2007-07-19 01:48:18 -0700 | [diff] [blame] | 2262 | */ |
| 2263 | int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt, |
| 2264 | const char *name, unsigned int flags, |
Al Viro | e0a0124 | 2011-06-27 17:00:37 -0400 | [diff] [blame] | 2265 | struct path *path) |
Josef 'Jeff' Sipek | 16f1820 | 2007-07-19 01:48:18 -0700 | [diff] [blame] | 2266 | { |
Al Viro | 9ad1aaa | 2015-05-12 16:44:39 -0400 | [diff] [blame] | 2267 | struct path root = {.mnt = mnt, .dentry = dentry}; |
Al Viro | 9ad1aaa | 2015-05-12 16:44:39 -0400 | [diff] [blame] | 2268 | /* the first argument of filename_lookup() is ignored with root */ |
Al Viro | abc9f5b | 2015-05-12 16:53:42 -0400 | [diff] [blame] | 2269 | return filename_lookup(AT_FDCWD, getname_kernel(name), |
| 2270 | flags , path, &root); |
Josef 'Jeff' Sipek | 16f1820 | 2007-07-19 01:48:18 -0700 | [diff] [blame] | 2271 | } |
Al Viro | 4d35950 | 2014-03-14 12:20:17 -0400 | [diff] [blame] | 2272 | EXPORT_SYMBOL(vfs_path_lookup); |
Josef 'Jeff' Sipek | 16f1820 | 2007-07-19 01:48:18 -0700 | [diff] [blame] | 2273 | |
Christoph Hellwig | eead191 | 2007-10-16 23:25:38 -0700 | [diff] [blame] | 2274 | /** |
Randy Dunlap | a6b9191 | 2008-03-19 17:01:00 -0700 | [diff] [blame] | 2275 | * lookup_one_len - filesystem helper to lookup single pathname component |
Christoph Hellwig | eead191 | 2007-10-16 23:25:38 -0700 | [diff] [blame] | 2276 | * @name: pathname component to lookup |
| 2277 | * @base: base directory to lookup from |
| 2278 | * @len: maximum length @len should be interpreted to |
| 2279 | * |
Randy Dunlap | a6b9191 | 2008-03-19 17:01:00 -0700 | [diff] [blame] | 2280 | * Note that this routine is purely a helper for filesystem usage and should |
Al Viro | 9e7543e | 2015-02-23 02:49:48 -0500 | [diff] [blame] | 2281 | * not be called by generic code. |
Christoph Hellwig | eead191 | 2007-10-16 23:25:38 -0700 | [diff] [blame] | 2282 | */ |
James Morris | 057f6c0 | 2007-04-26 00:12:05 -0700 | [diff] [blame] | 2283 | struct dentry *lookup_one_len(const char *name, struct dentry *base, int len) |
| 2284 | { |
James Morris | 057f6c0 | 2007-04-26 00:12:05 -0700 | [diff] [blame] | 2285 | struct qstr this; |
Al Viro | 6a96ba5 | 2011-03-07 23:49:20 -0500 | [diff] [blame] | 2286 | unsigned int c; |
Miklos Szeredi | cda309d | 2012-03-26 12:54:21 +0200 | [diff] [blame] | 2287 | int err; |
James Morris | 057f6c0 | 2007-04-26 00:12:05 -0700 | [diff] [blame] | 2288 | |
David Woodhouse | 2f9092e | 2009-04-20 23:18:37 +0100 | [diff] [blame] | 2289 | WARN_ON_ONCE(!mutex_is_locked(&base->d_inode->i_mutex)); |
| 2290 | |
Al Viro | 6a96ba5 | 2011-03-07 23:49:20 -0500 | [diff] [blame] | 2291 | this.name = name; |
| 2292 | this.len = len; |
Linus Torvalds | 0145acc | 2012-03-02 14:32:59 -0800 | [diff] [blame] | 2293 | this.hash = full_name_hash(name, len); |
Al Viro | 6a96ba5 | 2011-03-07 23:49:20 -0500 | [diff] [blame] | 2294 | if (!len) |
| 2295 | return ERR_PTR(-EACCES); |
| 2296 | |
Al Viro | 21d8a15 | 2012-11-29 22:17:21 -0500 | [diff] [blame] | 2297 | if (unlikely(name[0] == '.')) { |
| 2298 | if (len < 2 || (len == 2 && name[1] == '.')) |
| 2299 | return ERR_PTR(-EACCES); |
| 2300 | } |
| 2301 | |
Al Viro | 6a96ba5 | 2011-03-07 23:49:20 -0500 | [diff] [blame] | 2302 | while (len--) { |
| 2303 | c = *(const unsigned char *)name++; |
| 2304 | if (c == '/' || c == '\0') |
| 2305 | return ERR_PTR(-EACCES); |
Al Viro | 6a96ba5 | 2011-03-07 23:49:20 -0500 | [diff] [blame] | 2306 | } |
Al Viro | 5a202bc | 2011-03-08 14:17:44 -0500 | [diff] [blame] | 2307 | /* |
| 2308 | * See if the low-level filesystem might want |
| 2309 | * to use its own hash.. |
| 2310 | */ |
| 2311 | if (base->d_flags & DCACHE_OP_HASH) { |
Linus Torvalds | da53be1 | 2013-05-21 15:22:44 -0700 | [diff] [blame] | 2312 | int err = base->d_op->d_hash(base, &this); |
Al Viro | 5a202bc | 2011-03-08 14:17:44 -0500 | [diff] [blame] | 2313 | if (err < 0) |
| 2314 | return ERR_PTR(err); |
| 2315 | } |
Christoph Hellwig | eead191 | 2007-10-16 23:25:38 -0700 | [diff] [blame] | 2316 | |
Miklos Szeredi | cda309d | 2012-03-26 12:54:21 +0200 | [diff] [blame] | 2317 | err = inode_permission(base->d_inode, MAY_EXEC); |
| 2318 | if (err) |
| 2319 | return ERR_PTR(err); |
| 2320 | |
Al Viro | 72bd866 | 2012-06-10 17:17:17 -0400 | [diff] [blame] | 2321 | return __lookup_hash(&this, base, 0); |
James Morris | 057f6c0 | 2007-04-26 00:12:05 -0700 | [diff] [blame] | 2322 | } |
Al Viro | 4d35950 | 2014-03-14 12:20:17 -0400 | [diff] [blame] | 2323 | EXPORT_SYMBOL(lookup_one_len); |
James Morris | 057f6c0 | 2007-04-26 00:12:05 -0700 | [diff] [blame] | 2324 | |
Andy Whitcroft | 1fa1e7f | 2011-11-02 09:44:39 +0100 | [diff] [blame] | 2325 | int user_path_at_empty(int dfd, const char __user *name, unsigned flags, |
| 2326 | struct path *path, int *empty) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2327 | { |
Al Viro | abc9f5b | 2015-05-12 16:53:42 -0400 | [diff] [blame] | 2328 | return filename_lookup(dfd, getname_flags(name, flags, empty), |
| 2329 | flags, path, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2330 | } |
Al Viro | b853a16 | 2015-05-13 09:12:02 -0400 | [diff] [blame] | 2331 | EXPORT_SYMBOL(user_path_at_empty); |
Andy Whitcroft | 1fa1e7f | 2011-11-02 09:44:39 +0100 | [diff] [blame] | 2332 | |
Jeff Layton | 873f1ee | 2012-10-10 15:25:29 -0400 | [diff] [blame] | 2333 | /* |
| 2334 | * NB: most callers don't do anything directly with the reference to the |
| 2335 | * to struct filename, but the nd->last pointer points into the name string |
| 2336 | * allocated by getname. So we must hold the reference to it until all |
| 2337 | * path-walking is complete. |
| 2338 | */ |
Al Viro | a2ec4a2 | 2015-05-13 06:57:49 -0400 | [diff] [blame] | 2339 | static inline struct filename * |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 2340 | user_path_parent(int dfd, const char __user *path, |
| 2341 | struct path *parent, |
| 2342 | struct qstr *last, |
| 2343 | int *type, |
Jeff Layton | 9e790bd | 2012-12-11 12:10:09 -0500 | [diff] [blame] | 2344 | unsigned int flags) |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2345 | { |
Jeff Layton | 9e790bd | 2012-12-11 12:10:09 -0500 | [diff] [blame] | 2346 | /* only LOOKUP_REVAL is allowed in extra flags */ |
Al Viro | 5c31b6c | 2015-05-12 17:32:54 -0400 | [diff] [blame] | 2347 | return filename_parentat(dfd, getname(path), flags & LOOKUP_REVAL, |
| 2348 | parent, last, type); |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2349 | } |
| 2350 | |
Jeff Layton | 8033426 | 2013-07-26 06:23:25 -0400 | [diff] [blame] | 2351 | /** |
Al Viro | 197df04 | 2013-09-08 14:03:27 -0400 | [diff] [blame] | 2352 | * mountpoint_last - look up last component for umount |
Jeff Layton | 8033426 | 2013-07-26 06:23:25 -0400 | [diff] [blame] | 2353 | * @nd: pathwalk nameidata - currently pointing at parent directory of "last" |
| 2354 | * @path: pointer to container for result |
| 2355 | * |
| 2356 | * This is a special lookup_last function just for umount. In this case, we |
| 2357 | * need to resolve the path without doing any revalidation. |
| 2358 | * |
| 2359 | * The nameidata should be the result of doing a LOOKUP_PARENT pathwalk. Since |
| 2360 | * mountpoints are always pinned in the dcache, their ancestors are too. Thus, |
| 2361 | * in almost all cases, this lookup will be served out of the dcache. The only |
| 2362 | * cases where it won't are if nd->last refers to a symlink or the path is |
| 2363 | * bogus and it doesn't exist. |
| 2364 | * |
| 2365 | * Returns: |
| 2366 | * -error: if there was an error during lookup. This includes -ENOENT if the |
| 2367 | * lookup found a negative dentry. The nd->path reference will also be |
| 2368 | * put in this case. |
| 2369 | * |
| 2370 | * 0: if we successfully resolved nd->path and found it to not to be a |
| 2371 | * symlink that needs to be followed. "path" will also be populated. |
| 2372 | * The nd->path reference will also be put. |
| 2373 | * |
| 2374 | * 1: if we successfully resolved nd->last and found it to be a symlink |
| 2375 | * that needs to be followed. "path" will be populated with the path |
| 2376 | * to the link, and nd->path will *not* be put. |
| 2377 | */ |
| 2378 | static int |
Al Viro | 197df04 | 2013-09-08 14:03:27 -0400 | [diff] [blame] | 2379 | mountpoint_last(struct nameidata *nd, struct path *path) |
Jeff Layton | 8033426 | 2013-07-26 06:23:25 -0400 | [diff] [blame] | 2380 | { |
| 2381 | int error = 0; |
| 2382 | struct dentry *dentry; |
| 2383 | struct dentry *dir = nd->path.dentry; |
| 2384 | |
Al Viro | 3575952 | 2013-09-08 13:41:33 -0400 | [diff] [blame] | 2385 | /* If we're in rcuwalk, drop out of it to handle last component */ |
| 2386 | if (nd->flags & LOOKUP_RCU) { |
Al Viro | 6e9918b | 2015-05-05 09:26:05 -0400 | [diff] [blame] | 2387 | if (unlazy_walk(nd, NULL, 0)) |
Al Viro | deb106c | 2015-05-08 18:05:21 -0400 | [diff] [blame] | 2388 | return -ECHILD; |
Jeff Layton | 8033426 | 2013-07-26 06:23:25 -0400 | [diff] [blame] | 2389 | } |
| 2390 | |
| 2391 | nd->flags &= ~LOOKUP_PARENT; |
| 2392 | |
| 2393 | if (unlikely(nd->last_type != LAST_NORM)) { |
| 2394 | error = handle_dots(nd, nd->last_type); |
Al Viro | 3575952 | 2013-09-08 13:41:33 -0400 | [diff] [blame] | 2395 | if (error) |
Al Viro | deb106c | 2015-05-08 18:05:21 -0400 | [diff] [blame] | 2396 | return error; |
Al Viro | 3575952 | 2013-09-08 13:41:33 -0400 | [diff] [blame] | 2397 | dentry = dget(nd->path.dentry); |
| 2398 | goto done; |
Jeff Layton | 8033426 | 2013-07-26 06:23:25 -0400 | [diff] [blame] | 2399 | } |
| 2400 | |
| 2401 | mutex_lock(&dir->d_inode->i_mutex); |
| 2402 | dentry = d_lookup(dir, &nd->last); |
| 2403 | if (!dentry) { |
| 2404 | /* |
| 2405 | * No cached dentry. Mounted dentries are pinned in the cache, |
| 2406 | * so that means that this dentry is probably a symlink or the |
| 2407 | * path doesn't actually point to a mounted dentry. |
| 2408 | */ |
| 2409 | dentry = d_alloc(dir, &nd->last); |
| 2410 | if (!dentry) { |
Dave Jones | bcceeeb | 2013-09-10 17:04:25 -0400 | [diff] [blame] | 2411 | mutex_unlock(&dir->d_inode->i_mutex); |
Al Viro | deb106c | 2015-05-08 18:05:21 -0400 | [diff] [blame] | 2412 | return -ENOMEM; |
Jeff Layton | 8033426 | 2013-07-26 06:23:25 -0400 | [diff] [blame] | 2413 | } |
Al Viro | 3575952 | 2013-09-08 13:41:33 -0400 | [diff] [blame] | 2414 | dentry = lookup_real(dir->d_inode, dentry, nd->flags); |
Dave Jones | bcceeeb | 2013-09-10 17:04:25 -0400 | [diff] [blame] | 2415 | if (IS_ERR(dentry)) { |
| 2416 | mutex_unlock(&dir->d_inode->i_mutex); |
Al Viro | deb106c | 2015-05-08 18:05:21 -0400 | [diff] [blame] | 2417 | return PTR_ERR(dentry); |
Dave Jones | bcceeeb | 2013-09-10 17:04:25 -0400 | [diff] [blame] | 2418 | } |
Jeff Layton | 8033426 | 2013-07-26 06:23:25 -0400 | [diff] [blame] | 2419 | } |
| 2420 | mutex_unlock(&dir->d_inode->i_mutex); |
| 2421 | |
Al Viro | 3575952 | 2013-09-08 13:41:33 -0400 | [diff] [blame] | 2422 | done: |
David Howells | 698934d | 2015-03-17 17:33:52 +0000 | [diff] [blame] | 2423 | if (d_is_negative(dentry)) { |
Al Viro | 3575952 | 2013-09-08 13:41:33 -0400 | [diff] [blame] | 2424 | dput(dentry); |
Al Viro | deb106c | 2015-05-08 18:05:21 -0400 | [diff] [blame] | 2425 | return -ENOENT; |
Jeff Layton | 8033426 | 2013-07-26 06:23:25 -0400 | [diff] [blame] | 2426 | } |
Al Viro | 191d7f7 | 2015-05-04 08:26:45 -0400 | [diff] [blame] | 2427 | if (nd->depth) |
| 2428 | put_link(nd); |
Al Viro | 3575952 | 2013-09-08 13:41:33 -0400 | [diff] [blame] | 2429 | path->dentry = dentry; |
Vasily Averin | 295dc39 | 2014-07-21 12:30:23 +0400 | [diff] [blame] | 2430 | path->mnt = nd->path.mnt; |
Al Viro | 181548c | 2015-05-07 19:54:34 -0400 | [diff] [blame] | 2431 | error = should_follow_link(nd, path, nd->flags & LOOKUP_FOLLOW, |
| 2432 | d_backing_inode(dentry), 0); |
Al Viro | deb106c | 2015-05-08 18:05:21 -0400 | [diff] [blame] | 2433 | if (unlikely(error)) |
Al Viro | d63ff28 | 2015-05-04 18:13:23 -0400 | [diff] [blame] | 2434 | return error; |
Vasily Averin | 295dc39 | 2014-07-21 12:30:23 +0400 | [diff] [blame] | 2435 | mntget(path->mnt); |
Al Viro | 3575952 | 2013-09-08 13:41:33 -0400 | [diff] [blame] | 2436 | follow_mount(path); |
Al Viro | deb106c | 2015-05-08 18:05:21 -0400 | [diff] [blame] | 2437 | return 0; |
Jeff Layton | 8033426 | 2013-07-26 06:23:25 -0400 | [diff] [blame] | 2438 | } |
| 2439 | |
| 2440 | /** |
Al Viro | 197df04 | 2013-09-08 14:03:27 -0400 | [diff] [blame] | 2441 | * path_mountpoint - look up a path to be umounted |
Masanari Iida | 2a78b85 | 2015-09-09 15:39:23 -0700 | [diff] [blame] | 2442 | * @nd: lookup context |
Jeff Layton | 8033426 | 2013-07-26 06:23:25 -0400 | [diff] [blame] | 2443 | * @flags: lookup flags |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 2444 | * @path: pointer to container for result |
Jeff Layton | 8033426 | 2013-07-26 06:23:25 -0400 | [diff] [blame] | 2445 | * |
| 2446 | * Look up the given name, but don't attempt to revalidate the last component. |
Randy Dunlap | 606d6fe | 2013-10-19 14:56:55 -0700 | [diff] [blame] | 2447 | * Returns 0 and "path" will be valid on success; Returns error otherwise. |
Jeff Layton | 8033426 | 2013-07-26 06:23:25 -0400 | [diff] [blame] | 2448 | */ |
| 2449 | static int |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 2450 | path_mountpoint(struct nameidata *nd, unsigned flags, struct path *path) |
Jeff Layton | 8033426 | 2013-07-26 06:23:25 -0400 | [diff] [blame] | 2451 | { |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 2452 | const char *s = path_init(nd, flags); |
Al Viro | 368ee9b | 2015-05-08 17:19:59 -0400 | [diff] [blame] | 2453 | int err; |
| 2454 | if (IS_ERR(s)) |
| 2455 | return PTR_ERR(s); |
Al Viro | 3bdba28 | 2015-05-08 17:37:07 -0400 | [diff] [blame] | 2456 | while (!(err = link_path_walk(s, nd)) && |
| 2457 | (err = mountpoint_last(nd, path)) > 0) { |
| 2458 | s = trailing_symlink(nd); |
| 2459 | if (IS_ERR(s)) { |
| 2460 | err = PTR_ERR(s); |
Jeff Layton | 8033426 | 2013-07-26 06:23:25 -0400 | [diff] [blame] | 2461 | break; |
Al Viro | 3bdba28 | 2015-05-08 17:37:07 -0400 | [diff] [blame] | 2462 | } |
Jeff Layton | 8033426 | 2013-07-26 06:23:25 -0400 | [diff] [blame] | 2463 | } |
Al Viro | deb106c | 2015-05-08 18:05:21 -0400 | [diff] [blame] | 2464 | terminate_walk(nd); |
Jeff Layton | 8033426 | 2013-07-26 06:23:25 -0400 | [diff] [blame] | 2465 | return err; |
| 2466 | } |
| 2467 | |
Al Viro | 2d86465 | 2013-09-08 20:18:44 -0400 | [diff] [blame] | 2468 | static int |
Al Viro | 668696d | 2015-02-22 19:44:00 -0500 | [diff] [blame] | 2469 | filename_mountpoint(int dfd, struct filename *name, struct path *path, |
Al Viro | 2d86465 | 2013-09-08 20:18:44 -0400 | [diff] [blame] | 2470 | unsigned int flags) |
| 2471 | { |
Al Viro | 9883d18 | 2015-05-13 07:28:08 -0400 | [diff] [blame] | 2472 | struct nameidata nd; |
Al Viro | cbaab2d | 2015-01-22 02:49:00 -0500 | [diff] [blame] | 2473 | int error; |
Al Viro | 668696d | 2015-02-22 19:44:00 -0500 | [diff] [blame] | 2474 | if (IS_ERR(name)) |
| 2475 | return PTR_ERR(name); |
Al Viro | 9883d18 | 2015-05-13 07:28:08 -0400 | [diff] [blame] | 2476 | set_nameidata(&nd, dfd, name); |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 2477 | error = path_mountpoint(&nd, flags | LOOKUP_RCU, path); |
Al Viro | 2d86465 | 2013-09-08 20:18:44 -0400 | [diff] [blame] | 2478 | if (unlikely(error == -ECHILD)) |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 2479 | error = path_mountpoint(&nd, flags, path); |
Al Viro | 2d86465 | 2013-09-08 20:18:44 -0400 | [diff] [blame] | 2480 | if (unlikely(error == -ESTALE)) |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 2481 | error = path_mountpoint(&nd, flags | LOOKUP_REVAL, path); |
Al Viro | 2d86465 | 2013-09-08 20:18:44 -0400 | [diff] [blame] | 2482 | if (likely(!error)) |
Al Viro | 668696d | 2015-02-22 19:44:00 -0500 | [diff] [blame] | 2483 | audit_inode(name, path->dentry, 0); |
Al Viro | 9883d18 | 2015-05-13 07:28:08 -0400 | [diff] [blame] | 2484 | restore_nameidata(); |
Al Viro | 668696d | 2015-02-22 19:44:00 -0500 | [diff] [blame] | 2485 | putname(name); |
Al Viro | 2d86465 | 2013-09-08 20:18:44 -0400 | [diff] [blame] | 2486 | return error; |
| 2487 | } |
| 2488 | |
Jeff Layton | 8033426 | 2013-07-26 06:23:25 -0400 | [diff] [blame] | 2489 | /** |
Al Viro | 197df04 | 2013-09-08 14:03:27 -0400 | [diff] [blame] | 2490 | * user_path_mountpoint_at - lookup a path from userland in order to umount it |
Jeff Layton | 8033426 | 2013-07-26 06:23:25 -0400 | [diff] [blame] | 2491 | * @dfd: directory file descriptor |
| 2492 | * @name: pathname from userland |
| 2493 | * @flags: lookup flags |
| 2494 | * @path: pointer to container to hold result |
| 2495 | * |
| 2496 | * A umount is a special case for path walking. We're not actually interested |
| 2497 | * in the inode in this situation, and ESTALE errors can be a problem. We |
| 2498 | * simply want track down the dentry and vfsmount attached at the mountpoint |
| 2499 | * and avoid revalidating the last component. |
| 2500 | * |
| 2501 | * Returns 0 and populates "path" on success. |
| 2502 | */ |
| 2503 | int |
Al Viro | 197df04 | 2013-09-08 14:03:27 -0400 | [diff] [blame] | 2504 | user_path_mountpoint_at(int dfd, const char __user *name, unsigned int flags, |
Jeff Layton | 8033426 | 2013-07-26 06:23:25 -0400 | [diff] [blame] | 2505 | struct path *path) |
| 2506 | { |
Al Viro | cbaab2d | 2015-01-22 02:49:00 -0500 | [diff] [blame] | 2507 | return filename_mountpoint(dfd, getname(name), path, flags); |
Jeff Layton | 8033426 | 2013-07-26 06:23:25 -0400 | [diff] [blame] | 2508 | } |
| 2509 | |
Al Viro | 2d86465 | 2013-09-08 20:18:44 -0400 | [diff] [blame] | 2510 | int |
| 2511 | kern_path_mountpoint(int dfd, const char *name, struct path *path, |
| 2512 | unsigned int flags) |
| 2513 | { |
Al Viro | cbaab2d | 2015-01-22 02:49:00 -0500 | [diff] [blame] | 2514 | return filename_mountpoint(dfd, getname_kernel(name), path, flags); |
Al Viro | 2d86465 | 2013-09-08 20:18:44 -0400 | [diff] [blame] | 2515 | } |
| 2516 | EXPORT_SYMBOL(kern_path_mountpoint); |
| 2517 | |
Miklos Szeredi | cbdf35b | 2014-10-24 00:14:36 +0200 | [diff] [blame] | 2518 | int __check_sticky(struct inode *dir, struct inode *inode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2519 | { |
Eric W. Biederman | 8e96e3b | 2012-03-03 21:17:15 -0800 | [diff] [blame] | 2520 | kuid_t fsuid = current_fsuid(); |
David Howells | da9592e | 2008-11-14 10:39:05 +1100 | [diff] [blame] | 2521 | |
Eric W. Biederman | 8e96e3b | 2012-03-03 21:17:15 -0800 | [diff] [blame] | 2522 | if (uid_eq(inode->i_uid, fsuid)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2523 | return 0; |
Eric W. Biederman | 8e96e3b | 2012-03-03 21:17:15 -0800 | [diff] [blame] | 2524 | if (uid_eq(dir->i_uid, fsuid)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2525 | return 0; |
Andy Lutomirski | 23adbe1 | 2014-06-10 12:45:42 -0700 | [diff] [blame] | 2526 | return !capable_wrt_inode_uidgid(inode, CAP_FOWNER); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2527 | } |
Miklos Szeredi | cbdf35b | 2014-10-24 00:14:36 +0200 | [diff] [blame] | 2528 | EXPORT_SYMBOL(__check_sticky); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2529 | |
| 2530 | /* |
| 2531 | * Check whether we can remove a link victim from directory dir, check |
| 2532 | * whether the type of victim is right. |
| 2533 | * 1. We can't do it if dir is read-only (done in permission()) |
| 2534 | * 2. We should have write and exec permissions on dir |
| 2535 | * 3. We can't remove anything from append-only dir |
| 2536 | * 4. We can't do anything with immutable dir (done in permission()) |
| 2537 | * 5. If the sticky bit on dir is set we should either |
| 2538 | * a. be owner of dir, or |
| 2539 | * b. be owner of victim, or |
| 2540 | * c. have CAP_FOWNER capability |
| 2541 | * 6. If the victim is append-only or immutable we can't do antyhing with |
| 2542 | * links pointing to it. |
| 2543 | * 7. If we were asked to remove a directory and victim isn't one - ENOTDIR. |
| 2544 | * 8. If we were asked to remove a non-directory and victim isn't one - EISDIR. |
| 2545 | * 9. We can't remove a root or mountpoint. |
| 2546 | * 10. We don't allow removal of NFS sillyrenamed files; it's handled by |
| 2547 | * nfs_async_unlink(). |
| 2548 | */ |
David Howells | b18825a | 2013-09-12 19:22:53 +0100 | [diff] [blame] | 2549 | static int may_delete(struct inode *dir, struct dentry *victim, bool isdir) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2550 | { |
David Howells | 63afdfc | 2015-05-06 15:59:00 +0100 | [diff] [blame] | 2551 | struct inode *inode = d_backing_inode(victim); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2552 | int error; |
| 2553 | |
David Howells | b18825a | 2013-09-12 19:22:53 +0100 | [diff] [blame] | 2554 | if (d_is_negative(victim)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2555 | return -ENOENT; |
David Howells | b18825a | 2013-09-12 19:22:53 +0100 | [diff] [blame] | 2556 | BUG_ON(!inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2557 | |
| 2558 | BUG_ON(victim->d_parent->d_inode != dir); |
Jeff Layton | 4fa6b5e | 2012-10-10 15:25:25 -0400 | [diff] [blame] | 2559 | audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2560 | |
Al Viro | f419a2e | 2008-07-22 00:07:17 -0400 | [diff] [blame] | 2561 | error = inode_permission(dir, MAY_WRITE | MAY_EXEC); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2562 | if (error) |
| 2563 | return error; |
| 2564 | if (IS_APPEND(dir)) |
| 2565 | return -EPERM; |
David Howells | b18825a | 2013-09-12 19:22:53 +0100 | [diff] [blame] | 2566 | |
| 2567 | if (check_sticky(dir, inode) || IS_APPEND(inode) || |
| 2568 | IS_IMMUTABLE(inode) || IS_SWAPFILE(inode)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2569 | return -EPERM; |
| 2570 | if (isdir) { |
Miklos Szeredi | 44b1d53 | 2014-04-01 17:08:41 +0200 | [diff] [blame] | 2571 | if (!d_is_dir(victim)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2572 | return -ENOTDIR; |
| 2573 | if (IS_ROOT(victim)) |
| 2574 | return -EBUSY; |
Miklos Szeredi | 44b1d53 | 2014-04-01 17:08:41 +0200 | [diff] [blame] | 2575 | } else if (d_is_dir(victim)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2576 | return -EISDIR; |
| 2577 | if (IS_DEADDIR(dir)) |
| 2578 | return -ENOENT; |
| 2579 | if (victim->d_flags & DCACHE_NFSFS_RENAMED) |
| 2580 | return -EBUSY; |
| 2581 | return 0; |
| 2582 | } |
| 2583 | |
| 2584 | /* Check whether we can create an object with dentry child in directory |
| 2585 | * dir. |
| 2586 | * 1. We can't do it if child already exists (open has special treatment for |
| 2587 | * this case, but since we are inlined it's OK) |
| 2588 | * 2. We can't do it if dir is read-only (done in permission()) |
| 2589 | * 3. We should have write and exec permissions on dir |
| 2590 | * 4. We can't do it if dir is immutable (done in permission()) |
| 2591 | */ |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 2592 | static inline int may_create(struct inode *dir, struct dentry *child) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2593 | { |
Jeff Layton | 14e972b | 2013-05-08 10:25:58 -0400 | [diff] [blame] | 2594 | audit_inode_child(dir, child, AUDIT_TYPE_CHILD_CREATE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2595 | if (child->d_inode) |
| 2596 | return -EEXIST; |
| 2597 | if (IS_DEADDIR(dir)) |
| 2598 | return -ENOENT; |
Al Viro | f419a2e | 2008-07-22 00:07:17 -0400 | [diff] [blame] | 2599 | return inode_permission(dir, MAY_WRITE | MAY_EXEC); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2600 | } |
| 2601 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2602 | /* |
| 2603 | * p1 and p2 should be directories on the same fs. |
| 2604 | */ |
| 2605 | struct dentry *lock_rename(struct dentry *p1, struct dentry *p2) |
| 2606 | { |
| 2607 | struct dentry *p; |
| 2608 | |
| 2609 | if (p1 == p2) { |
Ingo Molnar | f2eace2 | 2006-07-03 00:25:05 -0700 | [diff] [blame] | 2610 | mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2611 | return NULL; |
| 2612 | } |
| 2613 | |
Arjan van de Ven | a11f3a0 | 2006-03-23 03:00:33 -0800 | [diff] [blame] | 2614 | mutex_lock(&p1->d_inode->i_sb->s_vfs_rename_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2615 | |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2616 | p = d_ancestor(p2, p1); |
| 2617 | if (p) { |
| 2618 | mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_PARENT); |
| 2619 | mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_CHILD); |
| 2620 | return p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2621 | } |
| 2622 | |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2623 | p = d_ancestor(p1, p2); |
| 2624 | if (p) { |
| 2625 | mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); |
| 2626 | mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD); |
| 2627 | return p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2628 | } |
| 2629 | |
Ingo Molnar | f2eace2 | 2006-07-03 00:25:05 -0700 | [diff] [blame] | 2630 | mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); |
Miklos Szeredi | d1b72cc | 2014-10-27 15:42:01 +0100 | [diff] [blame] | 2631 | mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_PARENT2); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2632 | return NULL; |
| 2633 | } |
Al Viro | 4d35950 | 2014-03-14 12:20:17 -0400 | [diff] [blame] | 2634 | EXPORT_SYMBOL(lock_rename); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2635 | |
| 2636 | void unlock_rename(struct dentry *p1, struct dentry *p2) |
| 2637 | { |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 2638 | mutex_unlock(&p1->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2639 | if (p1 != p2) { |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 2640 | mutex_unlock(&p2->d_inode->i_mutex); |
Arjan van de Ven | a11f3a0 | 2006-03-23 03:00:33 -0800 | [diff] [blame] | 2641 | mutex_unlock(&p1->d_inode->i_sb->s_vfs_rename_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2642 | } |
| 2643 | } |
Al Viro | 4d35950 | 2014-03-14 12:20:17 -0400 | [diff] [blame] | 2644 | EXPORT_SYMBOL(unlock_rename); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2645 | |
Al Viro | 4acdaf2 | 2011-07-26 01:42:34 -0400 | [diff] [blame] | 2646 | int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, |
Al Viro | 312b63f | 2012-06-10 18:09:36 -0400 | [diff] [blame] | 2647 | bool want_excl) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2648 | { |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 2649 | int error = may_create(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2650 | if (error) |
| 2651 | return error; |
| 2652 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 2653 | if (!dir->i_op->create) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2654 | return -EACCES; /* shouldn't it be ENOSYS? */ |
| 2655 | mode &= S_IALLUGO; |
| 2656 | mode |= S_IFREG; |
| 2657 | error = security_inode_create(dir, dentry, mode); |
| 2658 | if (error) |
| 2659 | return error; |
Al Viro | 312b63f | 2012-06-10 18:09:36 -0400 | [diff] [blame] | 2660 | error = dir->i_op->create(dir, dentry, mode, want_excl); |
Stephen Smalley | a74574a | 2005-09-09 13:01:44 -0700 | [diff] [blame] | 2661 | if (!error) |
Amy Griffis | f38aa94 | 2005-11-03 15:57:06 +0000 | [diff] [blame] | 2662 | fsnotify_create(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2663 | return error; |
| 2664 | } |
Al Viro | 4d35950 | 2014-03-14 12:20:17 -0400 | [diff] [blame] | 2665 | EXPORT_SYMBOL(vfs_create); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2666 | |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 2667 | static int may_open(struct path *path, int acc_mode, int flag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2668 | { |
Christoph Hellwig | 3fb6419 | 2008-10-24 09:58:10 +0200 | [diff] [blame] | 2669 | struct dentry *dentry = path->dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2670 | struct inode *inode = dentry->d_inode; |
| 2671 | int error; |
| 2672 | |
Al Viro | bcda765 | 2011-03-13 16:42:14 -0400 | [diff] [blame] | 2673 | /* O_PATH? */ |
| 2674 | if (!acc_mode) |
| 2675 | return 0; |
| 2676 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2677 | if (!inode) |
| 2678 | return -ENOENT; |
| 2679 | |
Christoph Hellwig | c8fe8f3 | 2009-01-05 19:27:23 +0100 | [diff] [blame] | 2680 | switch (inode->i_mode & S_IFMT) { |
| 2681 | case S_IFLNK: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2682 | return -ELOOP; |
Christoph Hellwig | c8fe8f3 | 2009-01-05 19:27:23 +0100 | [diff] [blame] | 2683 | case S_IFDIR: |
| 2684 | if (acc_mode & MAY_WRITE) |
| 2685 | return -EISDIR; |
| 2686 | break; |
| 2687 | case S_IFBLK: |
| 2688 | case S_IFCHR: |
Christoph Hellwig | 3fb6419 | 2008-10-24 09:58:10 +0200 | [diff] [blame] | 2689 | if (path->mnt->mnt_flags & MNT_NODEV) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2690 | return -EACCES; |
Christoph Hellwig | c8fe8f3 | 2009-01-05 19:27:23 +0100 | [diff] [blame] | 2691 | /*FALLTHRU*/ |
| 2692 | case S_IFIFO: |
| 2693 | case S_IFSOCK: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2694 | flag &= ~O_TRUNC; |
Christoph Hellwig | c8fe8f3 | 2009-01-05 19:27:23 +0100 | [diff] [blame] | 2695 | break; |
Dave Hansen | 4a3fd21 | 2008-02-15 14:37:48 -0800 | [diff] [blame] | 2696 | } |
Dave Hansen | b41572e | 2007-10-16 23:31:14 -0700 | [diff] [blame] | 2697 | |
Christoph Hellwig | 3fb6419 | 2008-10-24 09:58:10 +0200 | [diff] [blame] | 2698 | error = inode_permission(inode, acc_mode); |
Dave Hansen | b41572e | 2007-10-16 23:31:14 -0700 | [diff] [blame] | 2699 | if (error) |
| 2700 | return error; |
Mimi Zohar | 6146f0d | 2009-02-04 09:06:57 -0500 | [diff] [blame] | 2701 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2702 | /* |
| 2703 | * An append-only file must be opened in append mode for writing. |
| 2704 | */ |
| 2705 | if (IS_APPEND(inode)) { |
Al Viro | 8737c93 | 2009-12-24 06:47:55 -0500 | [diff] [blame] | 2706 | if ((flag & O_ACCMODE) != O_RDONLY && !(flag & O_APPEND)) |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 2707 | return -EPERM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2708 | if (flag & O_TRUNC) |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 2709 | return -EPERM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2710 | } |
| 2711 | |
| 2712 | /* O_NOATIME can only be set by the owner or superuser */ |
Serge E. Hallyn | 2e14967 | 2011-03-23 16:43:26 -0700 | [diff] [blame] | 2713 | if (flag & O_NOATIME && !inode_owner_or_capable(inode)) |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 2714 | return -EPERM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2715 | |
J. Bruce Fields | f3c7691e | 2011-09-21 10:58:13 -0400 | [diff] [blame] | 2716 | return 0; |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 2717 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2718 | |
Jeff Layton | e1181ee | 2010-12-07 16:19:50 -0500 | [diff] [blame] | 2719 | static int handle_truncate(struct file *filp) |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 2720 | { |
Jeff Layton | e1181ee | 2010-12-07 16:19:50 -0500 | [diff] [blame] | 2721 | struct path *path = &filp->f_path; |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 2722 | struct inode *inode = path->dentry->d_inode; |
| 2723 | int error = get_write_access(inode); |
| 2724 | if (error) |
| 2725 | return error; |
| 2726 | /* |
| 2727 | * Refuse to truncate files with mandatory locks held on them. |
| 2728 | */ |
Jeff Layton | d7a0698 | 2014-03-10 09:54:15 -0400 | [diff] [blame] | 2729 | error = locks_verify_locked(filp); |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 2730 | if (!error) |
Tetsuo Handa | ea0d3ab | 2010-06-02 13:24:43 +0900 | [diff] [blame] | 2731 | error = security_path_truncate(path); |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 2732 | if (!error) { |
| 2733 | error = do_truncate(path->dentry, 0, |
| 2734 | ATTR_MTIME|ATTR_CTIME|ATTR_OPEN, |
Jeff Layton | e1181ee | 2010-12-07 16:19:50 -0500 | [diff] [blame] | 2735 | filp); |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 2736 | } |
| 2737 | put_write_access(inode); |
Mimi Zohar | acd0c93 | 2009-09-04 13:08:46 -0400 | [diff] [blame] | 2738 | return error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2739 | } |
| 2740 | |
Dave Hansen | d57999e | 2008-02-15 14:37:27 -0800 | [diff] [blame] | 2741 | static inline int open_to_namei_flags(int flag) |
| 2742 | { |
Al Viro | 8a5e929 | 2011-06-25 19:15:54 -0400 | [diff] [blame] | 2743 | if ((flag & O_ACCMODE) == 3) |
| 2744 | flag--; |
Dave Hansen | d57999e | 2008-02-15 14:37:27 -0800 | [diff] [blame] | 2745 | return flag; |
| 2746 | } |
| 2747 | |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2748 | static int may_o_create(struct path *dir, struct dentry *dentry, umode_t mode) |
| 2749 | { |
| 2750 | int error = security_path_mknod(dir, dentry, mode, 0); |
| 2751 | if (error) |
| 2752 | return error; |
| 2753 | |
| 2754 | error = inode_permission(dir->dentry->d_inode, MAY_WRITE | MAY_EXEC); |
| 2755 | if (error) |
| 2756 | return error; |
| 2757 | |
| 2758 | return security_inode_create(dir->dentry->d_inode, dentry, mode); |
| 2759 | } |
| 2760 | |
David Howells | 1acf0af | 2012-06-14 16:13:46 +0100 | [diff] [blame] | 2761 | /* |
| 2762 | * Attempt to atomically look up, create and open a file from a negative |
| 2763 | * dentry. |
| 2764 | * |
| 2765 | * Returns 0 if successful. The file will have been created and attached to |
| 2766 | * @file by the filesystem calling finish_open(). |
| 2767 | * |
| 2768 | * Returns 1 if the file was looked up only or didn't need creating. The |
| 2769 | * caller will need to perform the open themselves. @path will have been |
| 2770 | * updated to point to the new dentry. This may be negative. |
| 2771 | * |
| 2772 | * Returns an error code otherwise. |
| 2773 | */ |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2774 | static int atomic_open(struct nameidata *nd, struct dentry *dentry, |
| 2775 | struct path *path, struct file *file, |
| 2776 | const struct open_flags *op, |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 2777 | bool got_write, bool need_lookup, |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2778 | int *opened) |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2779 | { |
| 2780 | struct inode *dir = nd->path.dentry->d_inode; |
| 2781 | unsigned open_flag = open_to_namei_flags(op->open_flag); |
| 2782 | umode_t mode; |
| 2783 | int error; |
| 2784 | int acc_mode; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2785 | int create_error = 0; |
| 2786 | struct dentry *const DENTRY_NOT_SET = (void *) -1UL; |
Miklos Szeredi | 116cc02 | 2013-09-16 14:52:05 +0200 | [diff] [blame] | 2787 | bool excl; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2788 | |
| 2789 | BUG_ON(dentry->d_inode); |
| 2790 | |
| 2791 | /* Don't create child dentry for a dead directory. */ |
| 2792 | if (unlikely(IS_DEADDIR(dir))) { |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2793 | error = -ENOENT; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2794 | goto out; |
| 2795 | } |
| 2796 | |
Miklos Szeredi | 62b259d | 2012-08-15 13:01:24 +0200 | [diff] [blame] | 2797 | mode = op->mode; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2798 | if ((open_flag & O_CREAT) && !IS_POSIXACL(dir)) |
| 2799 | mode &= ~current_umask(); |
| 2800 | |
Miklos Szeredi | 116cc02 | 2013-09-16 14:52:05 +0200 | [diff] [blame] | 2801 | excl = (open_flag & (O_EXCL | O_CREAT)) == (O_EXCL | O_CREAT); |
| 2802 | if (excl) |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2803 | open_flag &= ~O_TRUNC; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2804 | |
| 2805 | /* |
| 2806 | * Checking write permission is tricky, bacuse we don't know if we are |
| 2807 | * going to actually need it: O_CREAT opens should work as long as the |
| 2808 | * file exists. But checking existence breaks atomicity. The trick is |
| 2809 | * to check access and if not granted clear O_CREAT from the flags. |
| 2810 | * |
| 2811 | * Another problem is returing the "right" error value (e.g. for an |
| 2812 | * O_EXCL open we want to return EEXIST not EROFS). |
| 2813 | */ |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 2814 | if (((open_flag & (O_CREAT | O_TRUNC)) || |
| 2815 | (open_flag & O_ACCMODE) != O_RDONLY) && unlikely(!got_write)) { |
| 2816 | if (!(open_flag & O_CREAT)) { |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2817 | /* |
| 2818 | * No O_CREATE -> atomicity not a requirement -> fall |
| 2819 | * back to lookup + open |
| 2820 | */ |
| 2821 | goto no_open; |
| 2822 | } else if (open_flag & (O_EXCL | O_TRUNC)) { |
| 2823 | /* Fall back and fail with the right error */ |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 2824 | create_error = -EROFS; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2825 | goto no_open; |
| 2826 | } else { |
| 2827 | /* No side effects, safe to clear O_CREAT */ |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 2828 | create_error = -EROFS; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2829 | open_flag &= ~O_CREAT; |
| 2830 | } |
| 2831 | } |
| 2832 | |
| 2833 | if (open_flag & O_CREAT) { |
Miklos Szeredi | 38227f7 | 2012-08-15 13:01:24 +0200 | [diff] [blame] | 2834 | error = may_o_create(&nd->path, dentry, mode); |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2835 | if (error) { |
| 2836 | create_error = error; |
| 2837 | if (open_flag & O_EXCL) |
| 2838 | goto no_open; |
| 2839 | open_flag &= ~O_CREAT; |
| 2840 | } |
| 2841 | } |
| 2842 | |
| 2843 | if (nd->flags & LOOKUP_DIRECTORY) |
| 2844 | open_flag |= O_DIRECTORY; |
| 2845 | |
Al Viro | 30d9049 | 2012-06-22 12:40:19 +0400 | [diff] [blame] | 2846 | file->f_path.dentry = DENTRY_NOT_SET; |
| 2847 | file->f_path.mnt = nd->path.mnt; |
| 2848 | error = dir->i_op->atomic_open(dir, dentry, file, open_flag, mode, |
Al Viro | 4723768 | 2012-06-10 05:01:45 -0400 | [diff] [blame] | 2849 | opened); |
Al Viro | d958527 | 2012-06-22 12:39:14 +0400 | [diff] [blame] | 2850 | if (error < 0) { |
Al Viro | d958527 | 2012-06-22 12:39:14 +0400 | [diff] [blame] | 2851 | if (create_error && error == -ENOENT) |
| 2852 | error = create_error; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2853 | goto out; |
| 2854 | } |
| 2855 | |
Al Viro | d958527 | 2012-06-22 12:39:14 +0400 | [diff] [blame] | 2856 | if (error) { /* returned 1, that is */ |
Al Viro | 30d9049 | 2012-06-22 12:40:19 +0400 | [diff] [blame] | 2857 | if (WARN_ON(file->f_path.dentry == DENTRY_NOT_SET)) { |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2858 | error = -EIO; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2859 | goto out; |
| 2860 | } |
Al Viro | 30d9049 | 2012-06-22 12:40:19 +0400 | [diff] [blame] | 2861 | if (file->f_path.dentry) { |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2862 | dput(dentry); |
Al Viro | 30d9049 | 2012-06-22 12:40:19 +0400 | [diff] [blame] | 2863 | dentry = file->f_path.dentry; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2864 | } |
Al Viro | 03da633 | 2013-09-16 19:22:33 -0400 | [diff] [blame] | 2865 | if (*opened & FILE_CREATED) |
| 2866 | fsnotify_create(dir, dentry); |
| 2867 | if (!dentry->d_inode) { |
| 2868 | WARN_ON(*opened & FILE_CREATED); |
| 2869 | if (create_error) { |
| 2870 | error = create_error; |
| 2871 | goto out; |
| 2872 | } |
| 2873 | } else { |
| 2874 | if (excl && !(*opened & FILE_CREATED)) { |
| 2875 | error = -EEXIST; |
| 2876 | goto out; |
| 2877 | } |
Sage Weil | 62b2ce9 | 2012-08-15 13:30:12 -0700 | [diff] [blame] | 2878 | } |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2879 | goto looked_up; |
| 2880 | } |
| 2881 | |
| 2882 | /* |
| 2883 | * We didn't have the inode before the open, so check open permission |
| 2884 | * here. |
| 2885 | */ |
Al Viro | 03da633 | 2013-09-16 19:22:33 -0400 | [diff] [blame] | 2886 | acc_mode = op->acc_mode; |
| 2887 | if (*opened & FILE_CREATED) { |
| 2888 | WARN_ON(!(open_flag & O_CREAT)); |
| 2889 | fsnotify_create(dir, dentry); |
| 2890 | acc_mode = MAY_OPEN; |
| 2891 | } |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2892 | error = may_open(&file->f_path, acc_mode, open_flag); |
| 2893 | if (error) |
| 2894 | fput(file); |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2895 | |
| 2896 | out: |
| 2897 | dput(dentry); |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2898 | return error; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2899 | |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2900 | no_open: |
| 2901 | if (need_lookup) { |
Al Viro | 72bd866 | 2012-06-10 17:17:17 -0400 | [diff] [blame] | 2902 | dentry = lookup_real(dir, dentry, nd->flags); |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2903 | if (IS_ERR(dentry)) |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2904 | return PTR_ERR(dentry); |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2905 | |
| 2906 | if (create_error) { |
| 2907 | int open_flag = op->open_flag; |
| 2908 | |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2909 | error = create_error; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2910 | if ((open_flag & O_EXCL)) { |
| 2911 | if (!dentry->d_inode) |
| 2912 | goto out; |
| 2913 | } else if (!dentry->d_inode) { |
| 2914 | goto out; |
| 2915 | } else if ((open_flag & O_TRUNC) && |
David Howells | e36cb0b | 2015-01-29 12:02:35 +0000 | [diff] [blame] | 2916 | d_is_reg(dentry)) { |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2917 | goto out; |
| 2918 | } |
| 2919 | /* will fail later, go on to get the right error */ |
| 2920 | } |
| 2921 | } |
| 2922 | looked_up: |
| 2923 | path->dentry = dentry; |
| 2924 | path->mnt = nd->path.mnt; |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2925 | return 1; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2926 | } |
| 2927 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2928 | /* |
David Howells | 1acf0af | 2012-06-14 16:13:46 +0100 | [diff] [blame] | 2929 | * Look up and maybe create and open the last component. |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2930 | * |
| 2931 | * Must be called with i_mutex held on parent. |
| 2932 | * |
David Howells | 1acf0af | 2012-06-14 16:13:46 +0100 | [diff] [blame] | 2933 | * Returns 0 if the file was successfully atomically created (if necessary) and |
| 2934 | * opened. In this case the file will be returned attached to @file. |
| 2935 | * |
| 2936 | * Returns 1 if the file was not completely opened at this time, though lookups |
| 2937 | * and creations will have been performed and the dentry returned in @path will |
| 2938 | * be positive upon return if O_CREAT was specified. If O_CREAT wasn't |
| 2939 | * specified then a negative dentry may be returned. |
| 2940 | * |
| 2941 | * An error code is returned otherwise. |
| 2942 | * |
| 2943 | * FILE_CREATE will be set in @*opened if the dentry was created and will be |
| 2944 | * cleared otherwise prior to returning. |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2945 | */ |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2946 | static int lookup_open(struct nameidata *nd, struct path *path, |
| 2947 | struct file *file, |
| 2948 | const struct open_flags *op, |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 2949 | bool got_write, int *opened) |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2950 | { |
| 2951 | struct dentry *dir = nd->path.dentry; |
Miklos Szeredi | 54ef487 | 2012-06-05 15:10:16 +0200 | [diff] [blame] | 2952 | struct inode *dir_inode = dir->d_inode; |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2953 | struct dentry *dentry; |
| 2954 | int error; |
Miklos Szeredi | 54ef487 | 2012-06-05 15:10:16 +0200 | [diff] [blame] | 2955 | bool need_lookup; |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2956 | |
Al Viro | 4723768 | 2012-06-10 05:01:45 -0400 | [diff] [blame] | 2957 | *opened &= ~FILE_CREATED; |
Al Viro | 201f956 | 2012-06-22 12:42:10 +0400 | [diff] [blame] | 2958 | dentry = lookup_dcache(&nd->last, dir, nd->flags, &need_lookup); |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2959 | if (IS_ERR(dentry)) |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2960 | return PTR_ERR(dentry); |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2961 | |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2962 | /* Cached positive dentry: will open in f_op->open */ |
| 2963 | if (!need_lookup && dentry->d_inode) |
| 2964 | goto out_no_open; |
| 2965 | |
| 2966 | if ((nd->flags & LOOKUP_OPEN) && dir_inode->i_op->atomic_open) { |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 2967 | return atomic_open(nd, dentry, path, file, op, got_write, |
Al Viro | 4723768 | 2012-06-10 05:01:45 -0400 | [diff] [blame] | 2968 | need_lookup, opened); |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2969 | } |
| 2970 | |
Miklos Szeredi | 54ef487 | 2012-06-05 15:10:16 +0200 | [diff] [blame] | 2971 | if (need_lookup) { |
| 2972 | BUG_ON(dentry->d_inode); |
| 2973 | |
Al Viro | 72bd866 | 2012-06-10 17:17:17 -0400 | [diff] [blame] | 2974 | dentry = lookup_real(dir_inode, dentry, nd->flags); |
Miklos Szeredi | 54ef487 | 2012-06-05 15:10:16 +0200 | [diff] [blame] | 2975 | if (IS_ERR(dentry)) |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2976 | return PTR_ERR(dentry); |
Miklos Szeredi | 54ef487 | 2012-06-05 15:10:16 +0200 | [diff] [blame] | 2977 | } |
| 2978 | |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2979 | /* Negative dentry, just create the file */ |
| 2980 | if (!dentry->d_inode && (op->open_flag & O_CREAT)) { |
| 2981 | umode_t mode = op->mode; |
| 2982 | if (!IS_POSIXACL(dir->d_inode)) |
| 2983 | mode &= ~current_umask(); |
| 2984 | /* |
| 2985 | * This write is needed to ensure that a |
| 2986 | * rw->ro transition does not occur between |
| 2987 | * the time when the file is created and when |
| 2988 | * a permanent write count is taken through |
Miklos Szeredi | 015c3bb | 2012-06-05 15:10:27 +0200 | [diff] [blame] | 2989 | * the 'struct file' in finish_open(). |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2990 | */ |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 2991 | if (!got_write) { |
| 2992 | error = -EROFS; |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2993 | goto out_dput; |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 2994 | } |
Al Viro | 4723768 | 2012-06-10 05:01:45 -0400 | [diff] [blame] | 2995 | *opened |= FILE_CREATED; |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2996 | error = security_path_mknod(&nd->path, dentry, mode, 0); |
| 2997 | if (error) |
| 2998 | goto out_dput; |
Al Viro | 312b63f | 2012-06-10 18:09:36 -0400 | [diff] [blame] | 2999 | error = vfs_create(dir->d_inode, dentry, mode, |
| 3000 | nd->flags & LOOKUP_EXCL); |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 3001 | if (error) |
| 3002 | goto out_dput; |
| 3003 | } |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 3004 | out_no_open: |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 3005 | path->dentry = dentry; |
| 3006 | path->mnt = nd->path.mnt; |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 3007 | return 1; |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 3008 | |
| 3009 | out_dput: |
| 3010 | dput(dentry); |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 3011 | return error; |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 3012 | } |
| 3013 | |
| 3014 | /* |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 3015 | * Handle the last step of open() |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 3016 | */ |
Al Viro | 896475d | 2015-04-22 18:02:17 -0400 | [diff] [blame] | 3017 | static int do_last(struct nameidata *nd, |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 3018 | struct file *file, const struct open_flags *op, |
Al Viro | 76ae2a5 | 2015-05-12 18:44:32 -0400 | [diff] [blame] | 3019 | int *opened) |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 3020 | { |
Al Viro | a1e2803 | 2009-12-24 02:12:06 -0500 | [diff] [blame] | 3021 | struct dentry *dir = nd->path.dentry; |
Al Viro | ca344a89 | 2011-03-09 00:36:45 -0500 | [diff] [blame] | 3022 | int open_flag = op->open_flag; |
Miklos Szeredi | 77d660a | 2012-06-05 15:10:30 +0200 | [diff] [blame] | 3023 | bool will_truncate = (open_flag & O_TRUNC) != 0; |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 3024 | bool got_write = false; |
Al Viro | bcda765 | 2011-03-13 16:42:14 -0400 | [diff] [blame] | 3025 | int acc_mode = op->acc_mode; |
Al Viro | 254cf58 | 2015-05-05 09:40:46 -0400 | [diff] [blame] | 3026 | unsigned seq; |
Miklos Szeredi | a1eb331 | 2012-05-21 17:30:07 +0200 | [diff] [blame] | 3027 | struct inode *inode; |
Miklos Szeredi | 16b1c1c | 2012-05-21 17:30:19 +0200 | [diff] [blame] | 3028 | struct path save_parent = { .dentry = NULL, .mnt = NULL }; |
Al Viro | 896475d | 2015-04-22 18:02:17 -0400 | [diff] [blame] | 3029 | struct path path; |
Miklos Szeredi | 16b1c1c | 2012-05-21 17:30:19 +0200 | [diff] [blame] | 3030 | bool retried = false; |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 3031 | int error; |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 3032 | |
Al Viro | c3e380b | 2011-02-23 13:39:45 -0500 | [diff] [blame] | 3033 | nd->flags &= ~LOOKUP_PARENT; |
| 3034 | nd->flags |= op->intent; |
| 3035 | |
Al Viro | bc77daa | 2013-06-06 09:12:33 -0400 | [diff] [blame] | 3036 | if (nd->last_type != LAST_NORM) { |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 3037 | error = handle_dots(nd, nd->last_type); |
Al Viro | deb106c | 2015-05-08 18:05:21 -0400 | [diff] [blame] | 3038 | if (unlikely(error)) |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 3039 | return error; |
Miklos Szeredi | e83db16 | 2012-06-05 15:10:29 +0200 | [diff] [blame] | 3040 | goto finish_open; |
Al Viro | 1f36f77 | 2009-12-26 10:56:19 -0500 | [diff] [blame] | 3041 | } |
Al Viro | 67ee3ad | 2009-12-26 07:01:01 -0500 | [diff] [blame] | 3042 | |
Al Viro | ca344a89 | 2011-03-09 00:36:45 -0500 | [diff] [blame] | 3043 | if (!(open_flag & O_CREAT)) { |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 3044 | if (nd->last.name[nd->last.len]) |
| 3045 | nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY; |
| 3046 | /* we _can_ be in RCU mode here */ |
Al Viro | 254cf58 | 2015-05-05 09:40:46 -0400 | [diff] [blame] | 3047 | error = lookup_fast(nd, &path, &inode, &seq); |
Miklos Szeredi | 7157486 | 2012-06-05 15:10:14 +0200 | [diff] [blame] | 3048 | if (likely(!error)) |
| 3049 | goto finish_lookup; |
Miklos Szeredi | a1eb331 | 2012-05-21 17:30:07 +0200 | [diff] [blame] | 3050 | |
Miklos Szeredi | 7157486 | 2012-06-05 15:10:14 +0200 | [diff] [blame] | 3051 | if (error < 0) |
Al Viro | deb106c | 2015-05-08 18:05:21 -0400 | [diff] [blame] | 3052 | return error; |
Miklos Szeredi | 37d7fff | 2012-06-05 15:10:12 +0200 | [diff] [blame] | 3053 | |
Miklos Szeredi | 7157486 | 2012-06-05 15:10:14 +0200 | [diff] [blame] | 3054 | BUG_ON(nd->inode != dir->d_inode); |
Miklos Szeredi | b6183df | 2012-06-05 15:10:13 +0200 | [diff] [blame] | 3055 | } else { |
| 3056 | /* create side of things */ |
| 3057 | /* |
| 3058 | * This will *only* deal with leaving RCU mode - LOOKUP_JUMPED |
| 3059 | * has been cleared when we got to the last component we are |
| 3060 | * about to look up |
| 3061 | */ |
| 3062 | error = complete_walk(nd); |
Al Viro | e8bb73d | 2015-05-08 16:28:42 -0400 | [diff] [blame] | 3063 | if (error) |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 3064 | return error; |
Miklos Szeredi | b6183df | 2012-06-05 15:10:13 +0200 | [diff] [blame] | 3065 | |
Al Viro | 76ae2a5 | 2015-05-12 18:44:32 -0400 | [diff] [blame] | 3066 | audit_inode(nd->name, dir, LOOKUP_PARENT); |
Miklos Szeredi | b6183df | 2012-06-05 15:10:13 +0200 | [diff] [blame] | 3067 | /* trailing slashes? */ |
Al Viro | deb106c | 2015-05-08 18:05:21 -0400 | [diff] [blame] | 3068 | if (unlikely(nd->last.name[nd->last.len])) |
| 3069 | return -EISDIR; |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 3070 | } |
| 3071 | |
Miklos Szeredi | 16b1c1c | 2012-05-21 17:30:19 +0200 | [diff] [blame] | 3072 | retry_lookup: |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 3073 | if (op->open_flag & (O_CREAT | O_TRUNC | O_WRONLY | O_RDWR)) { |
| 3074 | error = mnt_want_write(nd->path.mnt); |
| 3075 | if (!error) |
| 3076 | got_write = true; |
| 3077 | /* |
| 3078 | * do _not_ fail yet - we might not need that or fail with |
| 3079 | * a different error; let lookup_open() decide; we'll be |
| 3080 | * dropping this one anyway. |
| 3081 | */ |
| 3082 | } |
Al Viro | a1e2803 | 2009-12-24 02:12:06 -0500 | [diff] [blame] | 3083 | mutex_lock(&dir->d_inode->i_mutex); |
Al Viro | 896475d | 2015-04-22 18:02:17 -0400 | [diff] [blame] | 3084 | error = lookup_open(nd, &path, file, op, got_write, opened); |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 3085 | mutex_unlock(&dir->d_inode->i_mutex); |
Al Viro | a1e2803 | 2009-12-24 02:12:06 -0500 | [diff] [blame] | 3086 | |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 3087 | if (error <= 0) { |
| 3088 | if (error) |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 3089 | goto out; |
| 3090 | |
Al Viro | 4723768 | 2012-06-10 05:01:45 -0400 | [diff] [blame] | 3091 | if ((*opened & FILE_CREATED) || |
Al Viro | 496ad9a | 2013-01-23 17:07:38 -0500 | [diff] [blame] | 3092 | !S_ISREG(file_inode(file)->i_mode)) |
Miklos Szeredi | 77d660a | 2012-06-05 15:10:30 +0200 | [diff] [blame] | 3093 | will_truncate = false; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 3094 | |
Al Viro | 76ae2a5 | 2015-05-12 18:44:32 -0400 | [diff] [blame] | 3095 | audit_inode(nd->name, file->f_path.dentry, 0); |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 3096 | goto opened; |
| 3097 | } |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 3098 | |
Al Viro | 4723768 | 2012-06-10 05:01:45 -0400 | [diff] [blame] | 3099 | if (*opened & FILE_CREATED) { |
Al Viro | 9b44f1b | 2011-03-09 00:17:27 -0500 | [diff] [blame] | 3100 | /* Don't check for write permission, don't truncate */ |
Al Viro | ca344a89 | 2011-03-09 00:36:45 -0500 | [diff] [blame] | 3101 | open_flag &= ~O_TRUNC; |
Miklos Szeredi | 77d660a | 2012-06-05 15:10:30 +0200 | [diff] [blame] | 3102 | will_truncate = false; |
Al Viro | bcda765 | 2011-03-13 16:42:14 -0400 | [diff] [blame] | 3103 | acc_mode = MAY_OPEN; |
Al Viro | 896475d | 2015-04-22 18:02:17 -0400 | [diff] [blame] | 3104 | path_to_nameidata(&path, nd); |
Miklos Szeredi | e83db16 | 2012-06-05 15:10:29 +0200 | [diff] [blame] | 3105 | goto finish_open_created; |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 3106 | } |
| 3107 | |
| 3108 | /* |
Jeff Layton | 3134f37 | 2012-07-25 10:19:47 -0400 | [diff] [blame] | 3109 | * create/update audit record if it already exists. |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 3110 | */ |
Al Viro | 896475d | 2015-04-22 18:02:17 -0400 | [diff] [blame] | 3111 | if (d_is_positive(path.dentry)) |
Al Viro | 76ae2a5 | 2015-05-12 18:44:32 -0400 | [diff] [blame] | 3112 | audit_inode(nd->name, path.dentry, 0); |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 3113 | |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 3114 | /* |
| 3115 | * If atomic_open() acquired write access it is dropped now due to |
| 3116 | * possible mount and symlink following (this might be optimized away if |
| 3117 | * necessary...) |
| 3118 | */ |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 3119 | if (got_write) { |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 3120 | mnt_drop_write(nd->path.mnt); |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 3121 | got_write = false; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 3122 | } |
| 3123 | |
Al Viro | deb106c | 2015-05-08 18:05:21 -0400 | [diff] [blame] | 3124 | if (unlikely((open_flag & (O_EXCL | O_CREAT)) == (O_EXCL | O_CREAT))) { |
| 3125 | path_to_nameidata(&path, nd); |
| 3126 | return -EEXIST; |
| 3127 | } |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 3128 | |
NeilBrown | 756daf2 | 2015-03-23 13:37:38 +1100 | [diff] [blame] | 3129 | error = follow_managed(&path, nd); |
Al Viro | deb106c | 2015-05-08 18:05:21 -0400 | [diff] [blame] | 3130 | if (unlikely(error < 0)) |
| 3131 | return error; |
Al Viro | a3fbbde | 2011-11-07 21:21:26 +0000 | [diff] [blame] | 3132 | |
Miklos Szeredi | decf340 | 2012-05-21 17:30:08 +0200 | [diff] [blame] | 3133 | BUG_ON(nd->flags & LOOKUP_RCU); |
David Howells | 63afdfc | 2015-05-06 15:59:00 +0100 | [diff] [blame] | 3134 | inode = d_backing_inode(path.dentry); |
Al Viro | 254cf58 | 2015-05-05 09:40:46 -0400 | [diff] [blame] | 3135 | seq = 0; /* out of RCU mode, so the value doesn't matter */ |
Al Viro | deb106c | 2015-05-08 18:05:21 -0400 | [diff] [blame] | 3136 | if (unlikely(d_is_negative(path.dentry))) { |
Al Viro | 896475d | 2015-04-22 18:02:17 -0400 | [diff] [blame] | 3137 | path_to_nameidata(&path, nd); |
Al Viro | deb106c | 2015-05-08 18:05:21 -0400 | [diff] [blame] | 3138 | return -ENOENT; |
Miklos Szeredi | 54c33e7 | 2012-05-21 17:30:10 +0200 | [diff] [blame] | 3139 | } |
Al Viro | 766c4cb | 2015-05-07 19:24:57 -0400 | [diff] [blame] | 3140 | finish_lookup: |
Al Viro | d63ff28 | 2015-05-04 18:13:23 -0400 | [diff] [blame] | 3141 | if (nd->depth) |
| 3142 | put_link(nd); |
Al Viro | 181548c | 2015-05-07 19:54:34 -0400 | [diff] [blame] | 3143 | error = should_follow_link(nd, &path, nd->flags & LOOKUP_FOLLOW, |
| 3144 | inode, seq); |
Al Viro | deb106c | 2015-05-08 18:05:21 -0400 | [diff] [blame] | 3145 | if (unlikely(error)) |
Al Viro | d63ff28 | 2015-05-04 18:13:23 -0400 | [diff] [blame] | 3146 | return error; |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 3147 | |
Al Viro | 896475d | 2015-04-22 18:02:17 -0400 | [diff] [blame] | 3148 | if (unlikely(d_is_symlink(path.dentry)) && !(open_flag & O_PATH)) { |
| 3149 | path_to_nameidata(&path, nd); |
Al Viro | deb106c | 2015-05-08 18:05:21 -0400 | [diff] [blame] | 3150 | return -ELOOP; |
Al Viro | a5cfe2d | 2015-04-22 12:10:45 -0400 | [diff] [blame] | 3151 | } |
| 3152 | |
Al Viro | 896475d | 2015-04-22 18:02:17 -0400 | [diff] [blame] | 3153 | if ((nd->flags & LOOKUP_RCU) || nd->path.mnt != path.mnt) { |
| 3154 | path_to_nameidata(&path, nd); |
Miklos Szeredi | 16b1c1c | 2012-05-21 17:30:19 +0200 | [diff] [blame] | 3155 | } else { |
| 3156 | save_parent.dentry = nd->path.dentry; |
Al Viro | 896475d | 2015-04-22 18:02:17 -0400 | [diff] [blame] | 3157 | save_parent.mnt = mntget(path.mnt); |
| 3158 | nd->path.dentry = path.dentry; |
Miklos Szeredi | 16b1c1c | 2012-05-21 17:30:19 +0200 | [diff] [blame] | 3159 | |
| 3160 | } |
Miklos Szeredi | decf340 | 2012-05-21 17:30:08 +0200 | [diff] [blame] | 3161 | nd->inode = inode; |
Al Viro | 254cf58 | 2015-05-05 09:40:46 -0400 | [diff] [blame] | 3162 | nd->seq = seq; |
Al Viro | a3fbbde | 2011-11-07 21:21:26 +0000 | [diff] [blame] | 3163 | /* Why this, you ask? _Now_ we might have grown LOOKUP_JUMPED... */ |
Al Viro | bc77daa | 2013-06-06 09:12:33 -0400 | [diff] [blame] | 3164 | finish_open: |
Al Viro | a3fbbde | 2011-11-07 21:21:26 +0000 | [diff] [blame] | 3165 | error = complete_walk(nd); |
Miklos Szeredi | 16b1c1c | 2012-05-21 17:30:19 +0200 | [diff] [blame] | 3166 | if (error) { |
| 3167 | path_put(&save_parent); |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 3168 | return error; |
Miklos Szeredi | 16b1c1c | 2012-05-21 17:30:19 +0200 | [diff] [blame] | 3169 | } |
Al Viro | 76ae2a5 | 2015-05-12 18:44:32 -0400 | [diff] [blame] | 3170 | audit_inode(nd->name, nd->path.dentry, 0); |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 3171 | error = -EISDIR; |
Miklos Szeredi | 44b1d53 | 2014-04-01 17:08:41 +0200 | [diff] [blame] | 3172 | if ((open_flag & O_CREAT) && d_is_dir(nd->path.dentry)) |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 3173 | goto out; |
Miklos Szeredi | af2f554 | 2012-05-21 17:30:11 +0200 | [diff] [blame] | 3174 | error = -ENOTDIR; |
Miklos Szeredi | 44b1d53 | 2014-04-01 17:08:41 +0200 | [diff] [blame] | 3175 | if ((nd->flags & LOOKUP_DIRECTORY) && !d_can_lookup(nd->path.dentry)) |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 3176 | goto out; |
David Howells | 4bbcbd3b | 2015-03-17 22:16:40 +0000 | [diff] [blame] | 3177 | if (!d_is_reg(nd->path.dentry)) |
Miklos Szeredi | 77d660a | 2012-06-05 15:10:30 +0200 | [diff] [blame] | 3178 | will_truncate = false; |
Al Viro | 6c0d46c | 2011-03-09 00:59:59 -0500 | [diff] [blame] | 3179 | |
Al Viro | 0f9d1a1 | 2011-03-09 00:13:14 -0500 | [diff] [blame] | 3180 | if (will_truncate) { |
| 3181 | error = mnt_want_write(nd->path.mnt); |
| 3182 | if (error) |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 3183 | goto out; |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 3184 | got_write = true; |
Al Viro | 0f9d1a1 | 2011-03-09 00:13:14 -0500 | [diff] [blame] | 3185 | } |
Miklos Szeredi | e83db16 | 2012-06-05 15:10:29 +0200 | [diff] [blame] | 3186 | finish_open_created: |
Al Viro | bcda765 | 2011-03-13 16:42:14 -0400 | [diff] [blame] | 3187 | error = may_open(&nd->path, acc_mode, open_flag); |
Al Viro | ca344a89 | 2011-03-09 00:36:45 -0500 | [diff] [blame] | 3188 | if (error) |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 3189 | goto out; |
Miklos Szeredi | 4aa7c63 | 2014-10-24 00:14:35 +0200 | [diff] [blame] | 3190 | |
| 3191 | BUG_ON(*opened & FILE_OPENED); /* once it's opened, it's opened */ |
| 3192 | error = vfs_open(&nd->path, file, current_cred()); |
| 3193 | if (!error) { |
| 3194 | *opened |= FILE_OPENED; |
| 3195 | } else { |
Al Viro | 30d9049 | 2012-06-22 12:40:19 +0400 | [diff] [blame] | 3196 | if (error == -EOPENSTALE) |
Miklos Szeredi | f60dc3d | 2012-06-05 15:10:31 +0200 | [diff] [blame] | 3197 | goto stale_open; |
Miklos Szeredi | 015c3bb | 2012-06-05 15:10:27 +0200 | [diff] [blame] | 3198 | goto out; |
Miklos Szeredi | f60dc3d | 2012-06-05 15:10:31 +0200 | [diff] [blame] | 3199 | } |
Miklos Szeredi | a8277b9 | 2012-06-05 15:10:32 +0200 | [diff] [blame] | 3200 | opened: |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 3201 | error = open_check_o_direct(file); |
Miklos Szeredi | 015c3bb | 2012-06-05 15:10:27 +0200 | [diff] [blame] | 3202 | if (error) |
| 3203 | goto exit_fput; |
Dmitry Kasatkin | 3034a14 | 2014-06-27 18:15:44 +0300 | [diff] [blame] | 3204 | error = ima_file_check(file, op->acc_mode, *opened); |
Miklos Szeredi | aa4caad | 2012-06-05 15:10:28 +0200 | [diff] [blame] | 3205 | if (error) |
| 3206 | goto exit_fput; |
| 3207 | |
| 3208 | if (will_truncate) { |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 3209 | error = handle_truncate(file); |
Miklos Szeredi | aa4caad | 2012-06-05 15:10:28 +0200 | [diff] [blame] | 3210 | if (error) |
| 3211 | goto exit_fput; |
Al Viro | 0f9d1a1 | 2011-03-09 00:13:14 -0500 | [diff] [blame] | 3212 | } |
Al Viro | ca344a89 | 2011-03-09 00:36:45 -0500 | [diff] [blame] | 3213 | out: |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 3214 | if (got_write) |
Al Viro | 0f9d1a1 | 2011-03-09 00:13:14 -0500 | [diff] [blame] | 3215 | mnt_drop_write(nd->path.mnt); |
Miklos Szeredi | 16b1c1c | 2012-05-21 17:30:19 +0200 | [diff] [blame] | 3216 | path_put(&save_parent); |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 3217 | return error; |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 3218 | |
Miklos Szeredi | 015c3bb | 2012-06-05 15:10:27 +0200 | [diff] [blame] | 3219 | exit_fput: |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 3220 | fput(file); |
| 3221 | goto out; |
Miklos Szeredi | 015c3bb | 2012-06-05 15:10:27 +0200 | [diff] [blame] | 3222 | |
Miklos Szeredi | f60dc3d | 2012-06-05 15:10:31 +0200 | [diff] [blame] | 3223 | stale_open: |
| 3224 | /* If no saved parent or already retried then can't retry */ |
| 3225 | if (!save_parent.dentry || retried) |
| 3226 | goto out; |
| 3227 | |
| 3228 | BUG_ON(save_parent.dentry != dir); |
| 3229 | path_put(&nd->path); |
| 3230 | nd->path = save_parent; |
| 3231 | nd->inode = dir->d_inode; |
| 3232 | save_parent.mnt = NULL; |
| 3233 | save_parent.dentry = NULL; |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 3234 | if (got_write) { |
Miklos Szeredi | f60dc3d | 2012-06-05 15:10:31 +0200 | [diff] [blame] | 3235 | mnt_drop_write(nd->path.mnt); |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 3236 | got_write = false; |
Miklos Szeredi | f60dc3d | 2012-06-05 15:10:31 +0200 | [diff] [blame] | 3237 | } |
| 3238 | retried = true; |
| 3239 | goto retry_lookup; |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 3240 | } |
| 3241 | |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 3242 | static int do_tmpfile(struct nameidata *nd, unsigned flags, |
Al Viro | 60545d0 | 2013-06-07 01:20:27 -0400 | [diff] [blame] | 3243 | const struct open_flags *op, |
| 3244 | struct file *file, int *opened) |
| 3245 | { |
| 3246 | static const struct qstr name = QSTR_INIT("/", 1); |
Al Viro | 625b6d1 | 2015-05-12 16:36:12 -0400 | [diff] [blame] | 3247 | struct dentry *child; |
Al Viro | 60545d0 | 2013-06-07 01:20:27 -0400 | [diff] [blame] | 3248 | struct inode *dir; |
Al Viro | 625b6d1 | 2015-05-12 16:36:12 -0400 | [diff] [blame] | 3249 | struct path path; |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 3250 | int error = path_lookupat(nd, flags | LOOKUP_DIRECTORY, &path); |
Al Viro | 60545d0 | 2013-06-07 01:20:27 -0400 | [diff] [blame] | 3251 | if (unlikely(error)) |
| 3252 | return error; |
Al Viro | 625b6d1 | 2015-05-12 16:36:12 -0400 | [diff] [blame] | 3253 | error = mnt_want_write(path.mnt); |
Al Viro | 60545d0 | 2013-06-07 01:20:27 -0400 | [diff] [blame] | 3254 | if (unlikely(error)) |
| 3255 | goto out; |
Al Viro | 625b6d1 | 2015-05-12 16:36:12 -0400 | [diff] [blame] | 3256 | dir = path.dentry->d_inode; |
Al Viro | 60545d0 | 2013-06-07 01:20:27 -0400 | [diff] [blame] | 3257 | /* we want directory to be writable */ |
Al Viro | 625b6d1 | 2015-05-12 16:36:12 -0400 | [diff] [blame] | 3258 | error = inode_permission(dir, MAY_WRITE | MAY_EXEC); |
Al Viro | 60545d0 | 2013-06-07 01:20:27 -0400 | [diff] [blame] | 3259 | if (error) |
| 3260 | goto out2; |
Al Viro | 60545d0 | 2013-06-07 01:20:27 -0400 | [diff] [blame] | 3261 | if (!dir->i_op->tmpfile) { |
| 3262 | error = -EOPNOTSUPP; |
| 3263 | goto out2; |
| 3264 | } |
Al Viro | 625b6d1 | 2015-05-12 16:36:12 -0400 | [diff] [blame] | 3265 | child = d_alloc(path.dentry, &name); |
Al Viro | 60545d0 | 2013-06-07 01:20:27 -0400 | [diff] [blame] | 3266 | if (unlikely(!child)) { |
| 3267 | error = -ENOMEM; |
| 3268 | goto out2; |
| 3269 | } |
Al Viro | 625b6d1 | 2015-05-12 16:36:12 -0400 | [diff] [blame] | 3270 | dput(path.dentry); |
| 3271 | path.dentry = child; |
| 3272 | error = dir->i_op->tmpfile(dir, child, op->mode); |
Al Viro | 60545d0 | 2013-06-07 01:20:27 -0400 | [diff] [blame] | 3273 | if (error) |
| 3274 | goto out2; |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 3275 | audit_inode(nd->name, child, 0); |
Eric Rannaud | 69a91c2 | 2014-10-30 01:51:01 -0700 | [diff] [blame] | 3276 | /* Don't check for other permissions, the inode was just created */ |
Al Viro | 625b6d1 | 2015-05-12 16:36:12 -0400 | [diff] [blame] | 3277 | error = may_open(&path, MAY_OPEN, op->open_flag); |
Al Viro | 60545d0 | 2013-06-07 01:20:27 -0400 | [diff] [blame] | 3278 | if (error) |
| 3279 | goto out2; |
Al Viro | 625b6d1 | 2015-05-12 16:36:12 -0400 | [diff] [blame] | 3280 | file->f_path.mnt = path.mnt; |
| 3281 | error = finish_open(file, child, NULL, opened); |
Al Viro | 60545d0 | 2013-06-07 01:20:27 -0400 | [diff] [blame] | 3282 | if (error) |
| 3283 | goto out2; |
| 3284 | error = open_check_o_direct(file); |
Al Viro | f4e0c30 | 2013-06-11 08:34:36 +0400 | [diff] [blame] | 3285 | if (error) { |
Al Viro | 60545d0 | 2013-06-07 01:20:27 -0400 | [diff] [blame] | 3286 | fput(file); |
Al Viro | f4e0c30 | 2013-06-11 08:34:36 +0400 | [diff] [blame] | 3287 | } else if (!(op->open_flag & O_EXCL)) { |
| 3288 | struct inode *inode = file_inode(file); |
| 3289 | spin_lock(&inode->i_lock); |
| 3290 | inode->i_state |= I_LINKABLE; |
| 3291 | spin_unlock(&inode->i_lock); |
| 3292 | } |
Al Viro | 60545d0 | 2013-06-07 01:20:27 -0400 | [diff] [blame] | 3293 | out2: |
Al Viro | 625b6d1 | 2015-05-12 16:36:12 -0400 | [diff] [blame] | 3294 | mnt_drop_write(path.mnt); |
Al Viro | 60545d0 | 2013-06-07 01:20:27 -0400 | [diff] [blame] | 3295 | out: |
Al Viro | 625b6d1 | 2015-05-12 16:36:12 -0400 | [diff] [blame] | 3296 | path_put(&path); |
Al Viro | 60545d0 | 2013-06-07 01:20:27 -0400 | [diff] [blame] | 3297 | return error; |
| 3298 | } |
| 3299 | |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 3300 | static struct file *path_openat(struct nameidata *nd, |
| 3301 | const struct open_flags *op, unsigned flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3302 | { |
Al Viro | 368ee9b | 2015-05-08 17:19:59 -0400 | [diff] [blame] | 3303 | const char *s; |
Al Viro | 30d9049 | 2012-06-22 12:40:19 +0400 | [diff] [blame] | 3304 | struct file *file; |
Al Viro | 4723768 | 2012-06-10 05:01:45 -0400 | [diff] [blame] | 3305 | int opened = 0; |
Al Viro | 13aab42 | 2011-02-23 17:54:08 -0500 | [diff] [blame] | 3306 | int error; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 3307 | |
Al Viro | 30d9049 | 2012-06-22 12:40:19 +0400 | [diff] [blame] | 3308 | file = get_empty_filp(); |
Al Viro | 1afc99b | 2013-02-14 20:41:04 -0500 | [diff] [blame] | 3309 | if (IS_ERR(file)) |
| 3310 | return file; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 3311 | |
Al Viro | 30d9049 | 2012-06-22 12:40:19 +0400 | [diff] [blame] | 3312 | file->f_flags = op->open_flag; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 3313 | |
Al Viro | bb458c6 | 2013-07-13 13:26:37 +0400 | [diff] [blame] | 3314 | if (unlikely(file->f_flags & __O_TMPFILE)) { |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 3315 | error = do_tmpfile(nd, flags, op, file, &opened); |
Al Viro | f15133d | 2015-05-08 22:53:15 -0400 | [diff] [blame] | 3316 | goto out2; |
Al Viro | 60545d0 | 2013-06-07 01:20:27 -0400 | [diff] [blame] | 3317 | } |
| 3318 | |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 3319 | s = path_init(nd, flags); |
Al Viro | 368ee9b | 2015-05-08 17:19:59 -0400 | [diff] [blame] | 3320 | if (IS_ERR(s)) { |
| 3321 | put_filp(file); |
| 3322 | return ERR_CAST(s); |
| 3323 | } |
Al Viro | 3bdba28 | 2015-05-08 17:37:07 -0400 | [diff] [blame] | 3324 | while (!(error = link_path_walk(s, nd)) && |
Al Viro | 76ae2a5 | 2015-05-12 18:44:32 -0400 | [diff] [blame] | 3325 | (error = do_last(nd, file, op, &opened)) > 0) { |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 3326 | nd->flags &= ~(LOOKUP_OPEN|LOOKUP_CREATE|LOOKUP_EXCL); |
Al Viro | 3bdba28 | 2015-05-08 17:37:07 -0400 | [diff] [blame] | 3327 | s = trailing_symlink(nd); |
| 3328 | if (IS_ERR(s)) { |
| 3329 | error = PTR_ERR(s); |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 3330 | break; |
Al Viro | 3bdba28 | 2015-05-08 17:37:07 -0400 | [diff] [blame] | 3331 | } |
Al Viro | 806b681 | 2009-12-26 07:16:40 -0500 | [diff] [blame] | 3332 | } |
Al Viro | deb106c | 2015-05-08 18:05:21 -0400 | [diff] [blame] | 3333 | terminate_walk(nd); |
Al Viro | f15133d | 2015-05-08 22:53:15 -0400 | [diff] [blame] | 3334 | out2: |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 3335 | if (!(opened & FILE_OPENED)) { |
| 3336 | BUG_ON(!error); |
Al Viro | 30d9049 | 2012-06-22 12:40:19 +0400 | [diff] [blame] | 3337 | put_filp(file); |
Miklos Szeredi | 015c3bb | 2012-06-05 15:10:27 +0200 | [diff] [blame] | 3338 | } |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 3339 | if (unlikely(error)) { |
| 3340 | if (error == -EOPENSTALE) { |
| 3341 | if (flags & LOOKUP_RCU) |
| 3342 | error = -ECHILD; |
| 3343 | else |
| 3344 | error = -ESTALE; |
| 3345 | } |
| 3346 | file = ERR_PTR(error); |
| 3347 | } |
| 3348 | return file; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3349 | } |
| 3350 | |
Jeff Layton | 669abf4 | 2012-10-10 16:43:10 -0400 | [diff] [blame] | 3351 | struct file *do_filp_open(int dfd, struct filename *pathname, |
Al Viro | f9652e1 | 2013-06-11 08:23:01 +0400 | [diff] [blame] | 3352 | const struct open_flags *op) |
Al Viro | 13aab42 | 2011-02-23 17:54:08 -0500 | [diff] [blame] | 3353 | { |
Al Viro | 9883d18 | 2015-05-13 07:28:08 -0400 | [diff] [blame] | 3354 | struct nameidata nd; |
Al Viro | f9652e1 | 2013-06-11 08:23:01 +0400 | [diff] [blame] | 3355 | int flags = op->lookup_flags; |
Al Viro | 13aab42 | 2011-02-23 17:54:08 -0500 | [diff] [blame] | 3356 | struct file *filp; |
| 3357 | |
Al Viro | 9883d18 | 2015-05-13 07:28:08 -0400 | [diff] [blame] | 3358 | set_nameidata(&nd, dfd, pathname); |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 3359 | filp = path_openat(&nd, op, flags | LOOKUP_RCU); |
Al Viro | 13aab42 | 2011-02-23 17:54:08 -0500 | [diff] [blame] | 3360 | if (unlikely(filp == ERR_PTR(-ECHILD))) |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 3361 | filp = path_openat(&nd, op, flags); |
Al Viro | 13aab42 | 2011-02-23 17:54:08 -0500 | [diff] [blame] | 3362 | if (unlikely(filp == ERR_PTR(-ESTALE))) |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 3363 | filp = path_openat(&nd, op, flags | LOOKUP_REVAL); |
Al Viro | 9883d18 | 2015-05-13 07:28:08 -0400 | [diff] [blame] | 3364 | restore_nameidata(); |
Al Viro | 13aab42 | 2011-02-23 17:54:08 -0500 | [diff] [blame] | 3365 | return filp; |
| 3366 | } |
| 3367 | |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 3368 | struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt, |
Al Viro | f9652e1 | 2013-06-11 08:23:01 +0400 | [diff] [blame] | 3369 | const char *name, const struct open_flags *op) |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 3370 | { |
Al Viro | 9883d18 | 2015-05-13 07:28:08 -0400 | [diff] [blame] | 3371 | struct nameidata nd; |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 3372 | struct file *file; |
Paul Moore | 5168910 | 2015-01-22 00:00:03 -0500 | [diff] [blame] | 3373 | struct filename *filename; |
Al Viro | f9652e1 | 2013-06-11 08:23:01 +0400 | [diff] [blame] | 3374 | int flags = op->lookup_flags | LOOKUP_ROOT; |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 3375 | |
| 3376 | nd.root.mnt = mnt; |
| 3377 | nd.root.dentry = dentry; |
| 3378 | |
David Howells | b18825a | 2013-09-12 19:22:53 +0100 | [diff] [blame] | 3379 | if (d_is_symlink(dentry) && op->intent & LOOKUP_OPEN) |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 3380 | return ERR_PTR(-ELOOP); |
| 3381 | |
Paul Moore | 5168910 | 2015-01-22 00:00:03 -0500 | [diff] [blame] | 3382 | filename = getname_kernel(name); |
Viresh Kumar | a1c8368 | 2015-08-12 15:59:44 +0530 | [diff] [blame] | 3383 | if (IS_ERR(filename)) |
Paul Moore | 5168910 | 2015-01-22 00:00:03 -0500 | [diff] [blame] | 3384 | return ERR_CAST(filename); |
| 3385 | |
Al Viro | 9883d18 | 2015-05-13 07:28:08 -0400 | [diff] [blame] | 3386 | set_nameidata(&nd, -1, filename); |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 3387 | file = path_openat(&nd, op, flags | LOOKUP_RCU); |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 3388 | if (unlikely(file == ERR_PTR(-ECHILD))) |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 3389 | file = path_openat(&nd, op, flags); |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 3390 | if (unlikely(file == ERR_PTR(-ESTALE))) |
Al Viro | c8a53ee | 2015-05-12 18:43:07 -0400 | [diff] [blame] | 3391 | file = path_openat(&nd, op, flags | LOOKUP_REVAL); |
Al Viro | 9883d18 | 2015-05-13 07:28:08 -0400 | [diff] [blame] | 3392 | restore_nameidata(); |
Paul Moore | 5168910 | 2015-01-22 00:00:03 -0500 | [diff] [blame] | 3393 | putname(filename); |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 3394 | return file; |
| 3395 | } |
| 3396 | |
Al Viro | fa14a0b | 2015-01-22 02:16:49 -0500 | [diff] [blame] | 3397 | static struct dentry *filename_create(int dfd, struct filename *name, |
Jeff Layton | 1ac12b4 | 2012-12-11 12:10:06 -0500 | [diff] [blame] | 3398 | struct path *path, unsigned int lookup_flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3399 | { |
Christoph Hellwig | c663e5d | 2005-06-23 00:09:49 -0700 | [diff] [blame] | 3400 | struct dentry *dentry = ERR_PTR(-EEXIST); |
Al Viro | 391172c | 2015-05-09 11:19:16 -0400 | [diff] [blame] | 3401 | struct qstr last; |
| 3402 | int type; |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 3403 | int err2; |
Jeff Layton | 1ac12b4 | 2012-12-11 12:10:06 -0500 | [diff] [blame] | 3404 | int error; |
| 3405 | bool is_dir = (lookup_flags & LOOKUP_DIRECTORY); |
| 3406 | |
| 3407 | /* |
| 3408 | * Note that only LOOKUP_REVAL and LOOKUP_DIRECTORY matter here. Any |
| 3409 | * other flags passed in are ignored! |
| 3410 | */ |
| 3411 | lookup_flags &= LOOKUP_REVAL; |
| 3412 | |
Al Viro | 5c31b6c | 2015-05-12 17:32:54 -0400 | [diff] [blame] | 3413 | name = filename_parentat(dfd, name, lookup_flags, path, &last, &type); |
| 3414 | if (IS_ERR(name)) |
| 3415 | return ERR_CAST(name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3416 | |
Christoph Hellwig | c663e5d | 2005-06-23 00:09:49 -0700 | [diff] [blame] | 3417 | /* |
| 3418 | * Yucky last component or no last component at all? |
| 3419 | * (foo/., foo/.., /////) |
| 3420 | */ |
Al Viro | 5c31b6c | 2015-05-12 17:32:54 -0400 | [diff] [blame] | 3421 | if (unlikely(type != LAST_NORM)) |
Al Viro | ed75e95 | 2011-06-27 16:53:43 -0400 | [diff] [blame] | 3422 | goto out; |
Christoph Hellwig | c663e5d | 2005-06-23 00:09:49 -0700 | [diff] [blame] | 3423 | |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 3424 | /* don't fail immediately if it's r/o, at least try to report other errors */ |
Al Viro | 391172c | 2015-05-09 11:19:16 -0400 | [diff] [blame] | 3425 | err2 = mnt_want_write(path->mnt); |
Christoph Hellwig | c663e5d | 2005-06-23 00:09:49 -0700 | [diff] [blame] | 3426 | /* |
| 3427 | * Do the final lookup. |
| 3428 | */ |
Al Viro | 391172c | 2015-05-09 11:19:16 -0400 | [diff] [blame] | 3429 | lookup_flags |= LOOKUP_CREATE | LOOKUP_EXCL; |
| 3430 | mutex_lock_nested(&path->dentry->d_inode->i_mutex, I_MUTEX_PARENT); |
| 3431 | dentry = __lookup_hash(&last, path->dentry, lookup_flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3432 | if (IS_ERR(dentry)) |
Al Viro | a8104a9 | 2012-07-20 02:25:00 +0400 | [diff] [blame] | 3433 | goto unlock; |
Christoph Hellwig | c663e5d | 2005-06-23 00:09:49 -0700 | [diff] [blame] | 3434 | |
Al Viro | a8104a9 | 2012-07-20 02:25:00 +0400 | [diff] [blame] | 3435 | error = -EEXIST; |
David Howells | b18825a | 2013-09-12 19:22:53 +0100 | [diff] [blame] | 3436 | if (d_is_positive(dentry)) |
Al Viro | a8104a9 | 2012-07-20 02:25:00 +0400 | [diff] [blame] | 3437 | goto fail; |
David Howells | b18825a | 2013-09-12 19:22:53 +0100 | [diff] [blame] | 3438 | |
Christoph Hellwig | c663e5d | 2005-06-23 00:09:49 -0700 | [diff] [blame] | 3439 | /* |
| 3440 | * Special case - lookup gave negative, but... we had foo/bar/ |
| 3441 | * From the vfs_mknod() POV we just have a negative dentry - |
| 3442 | * all is fine. Let's be bastards - you had / on the end, you've |
| 3443 | * been asking for (non-existent) directory. -ENOENT for you. |
| 3444 | */ |
Al Viro | 391172c | 2015-05-09 11:19:16 -0400 | [diff] [blame] | 3445 | if (unlikely(!is_dir && last.name[last.len])) { |
Al Viro | a8104a9 | 2012-07-20 02:25:00 +0400 | [diff] [blame] | 3446 | error = -ENOENT; |
Al Viro | ed75e95 | 2011-06-27 16:53:43 -0400 | [diff] [blame] | 3447 | goto fail; |
Al Viro | e9baf6e | 2008-05-15 04:49:12 -0400 | [diff] [blame] | 3448 | } |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 3449 | if (unlikely(err2)) { |
| 3450 | error = err2; |
Al Viro | a8104a9 | 2012-07-20 02:25:00 +0400 | [diff] [blame] | 3451 | goto fail; |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 3452 | } |
Al Viro | 181c37b | 2015-05-12 17:21:25 -0400 | [diff] [blame] | 3453 | putname(name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3454 | return dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3455 | fail: |
Al Viro | a8104a9 | 2012-07-20 02:25:00 +0400 | [diff] [blame] | 3456 | dput(dentry); |
| 3457 | dentry = ERR_PTR(error); |
| 3458 | unlock: |
Al Viro | 391172c | 2015-05-09 11:19:16 -0400 | [diff] [blame] | 3459 | mutex_unlock(&path->dentry->d_inode->i_mutex); |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 3460 | if (!err2) |
Al Viro | 391172c | 2015-05-09 11:19:16 -0400 | [diff] [blame] | 3461 | mnt_drop_write(path->mnt); |
Al Viro | ed75e95 | 2011-06-27 16:53:43 -0400 | [diff] [blame] | 3462 | out: |
Al Viro | 391172c | 2015-05-09 11:19:16 -0400 | [diff] [blame] | 3463 | path_put(path); |
Al Viro | 181c37b | 2015-05-12 17:21:25 -0400 | [diff] [blame] | 3464 | putname(name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3465 | return dentry; |
| 3466 | } |
Al Viro | fa14a0b | 2015-01-22 02:16:49 -0500 | [diff] [blame] | 3467 | |
| 3468 | struct dentry *kern_path_create(int dfd, const char *pathname, |
| 3469 | struct path *path, unsigned int lookup_flags) |
| 3470 | { |
Al Viro | 181c37b | 2015-05-12 17:21:25 -0400 | [diff] [blame] | 3471 | return filename_create(dfd, getname_kernel(pathname), |
| 3472 | path, lookup_flags); |
Al Viro | fa14a0b | 2015-01-22 02:16:49 -0500 | [diff] [blame] | 3473 | } |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3474 | EXPORT_SYMBOL(kern_path_create); |
| 3475 | |
Al Viro | 921a165 | 2012-07-20 01:15:31 +0400 | [diff] [blame] | 3476 | void done_path_create(struct path *path, struct dentry *dentry) |
| 3477 | { |
| 3478 | dput(dentry); |
| 3479 | mutex_unlock(&path->dentry->d_inode->i_mutex); |
Al Viro | a8104a9 | 2012-07-20 02:25:00 +0400 | [diff] [blame] | 3480 | mnt_drop_write(path->mnt); |
Al Viro | 921a165 | 2012-07-20 01:15:31 +0400 | [diff] [blame] | 3481 | path_put(path); |
| 3482 | } |
| 3483 | EXPORT_SYMBOL(done_path_create); |
| 3484 | |
Al Viro | 520ae68 | 2015-05-13 07:00:28 -0400 | [diff] [blame] | 3485 | inline struct dentry *user_path_create(int dfd, const char __user *pathname, |
Jeff Layton | 1ac12b4 | 2012-12-11 12:10:06 -0500 | [diff] [blame] | 3486 | struct path *path, unsigned int lookup_flags) |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3487 | { |
Al Viro | 181c37b | 2015-05-12 17:21:25 -0400 | [diff] [blame] | 3488 | return filename_create(dfd, getname(pathname), path, lookup_flags); |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3489 | } |
| 3490 | EXPORT_SYMBOL(user_path_create); |
| 3491 | |
Al Viro | 1a67aaf | 2011-07-26 01:52:52 -0400 | [diff] [blame] | 3492 | int vfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3493 | { |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 3494 | int error = may_create(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3495 | |
| 3496 | if (error) |
| 3497 | return error; |
| 3498 | |
Eric W. Biederman | 975d6b3 | 2011-11-13 12:16:43 -0800 | [diff] [blame] | 3499 | if ((S_ISCHR(mode) || S_ISBLK(mode)) && !capable(CAP_MKNOD)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3500 | return -EPERM; |
| 3501 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 3502 | if (!dir->i_op->mknod) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3503 | return -EPERM; |
| 3504 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 3505 | error = devcgroup_inode_mknod(mode, dev); |
| 3506 | if (error) |
| 3507 | return error; |
| 3508 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3509 | error = security_inode_mknod(dir, dentry, mode, dev); |
| 3510 | if (error) |
| 3511 | return error; |
| 3512 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3513 | error = dir->i_op->mknod(dir, dentry, mode, dev); |
Stephen Smalley | a74574a | 2005-09-09 13:01:44 -0700 | [diff] [blame] | 3514 | if (!error) |
Amy Griffis | f38aa94 | 2005-11-03 15:57:06 +0000 | [diff] [blame] | 3515 | fsnotify_create(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3516 | return error; |
| 3517 | } |
Al Viro | 4d35950 | 2014-03-14 12:20:17 -0400 | [diff] [blame] | 3518 | EXPORT_SYMBOL(vfs_mknod); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3519 | |
Al Viro | f69aac0 | 2011-07-26 04:31:40 -0400 | [diff] [blame] | 3520 | static int may_mknod(umode_t mode) |
Dave Hansen | 463c319 | 2008-02-15 14:37:57 -0800 | [diff] [blame] | 3521 | { |
| 3522 | switch (mode & S_IFMT) { |
| 3523 | case S_IFREG: |
| 3524 | case S_IFCHR: |
| 3525 | case S_IFBLK: |
| 3526 | case S_IFIFO: |
| 3527 | case S_IFSOCK: |
| 3528 | case 0: /* zero mode translates to S_IFREG */ |
| 3529 | return 0; |
| 3530 | case S_IFDIR: |
| 3531 | return -EPERM; |
| 3532 | default: |
| 3533 | return -EINVAL; |
| 3534 | } |
| 3535 | } |
| 3536 | |
Al Viro | 8208a22 | 2011-07-25 17:32:17 -0400 | [diff] [blame] | 3537 | SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode, |
Heiko Carstens | 2e4d092 | 2009-01-14 14:14:31 +0100 | [diff] [blame] | 3538 | unsigned, dev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3539 | { |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 3540 | struct dentry *dentry; |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3541 | struct path path; |
| 3542 | int error; |
Jeff Layton | 972567f | 2012-12-20 16:00:10 -0500 | [diff] [blame] | 3543 | unsigned int lookup_flags = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3544 | |
Al Viro | 8e4bfca | 2012-07-20 01:17:26 +0400 | [diff] [blame] | 3545 | error = may_mknod(mode); |
| 3546 | if (error) |
| 3547 | return error; |
Jeff Layton | 972567f | 2012-12-20 16:00:10 -0500 | [diff] [blame] | 3548 | retry: |
| 3549 | dentry = user_path_create(dfd, filename, &path, lookup_flags); |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3550 | if (IS_ERR(dentry)) |
| 3551 | return PTR_ERR(dentry); |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 3552 | |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3553 | if (!IS_POSIXACL(path.dentry->d_inode)) |
Al Viro | ce3b0f8 | 2009-03-29 19:08:22 -0400 | [diff] [blame] | 3554 | mode &= ~current_umask(); |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3555 | error = security_path_mknod(&path, dentry, mode, dev); |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 3556 | if (error) |
Al Viro | a8104a9 | 2012-07-20 02:25:00 +0400 | [diff] [blame] | 3557 | goto out; |
Dave Hansen | 463c319 | 2008-02-15 14:37:57 -0800 | [diff] [blame] | 3558 | switch (mode & S_IFMT) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3559 | case 0: case S_IFREG: |
Al Viro | 312b63f | 2012-06-10 18:09:36 -0400 | [diff] [blame] | 3560 | error = vfs_create(path.dentry->d_inode,dentry,mode,true); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3561 | break; |
| 3562 | case S_IFCHR: case S_IFBLK: |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3563 | error = vfs_mknod(path.dentry->d_inode,dentry,mode, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3564 | new_decode_dev(dev)); |
| 3565 | break; |
| 3566 | case S_IFIFO: case S_IFSOCK: |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3567 | error = vfs_mknod(path.dentry->d_inode,dentry,mode,0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3568 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3569 | } |
Al Viro | a8104a9 | 2012-07-20 02:25:00 +0400 | [diff] [blame] | 3570 | out: |
Al Viro | 921a165 | 2012-07-20 01:15:31 +0400 | [diff] [blame] | 3571 | done_path_create(&path, dentry); |
Jeff Layton | 972567f | 2012-12-20 16:00:10 -0500 | [diff] [blame] | 3572 | if (retry_estale(error, lookup_flags)) { |
| 3573 | lookup_flags |= LOOKUP_REVAL; |
| 3574 | goto retry; |
| 3575 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3576 | return error; |
| 3577 | } |
| 3578 | |
Al Viro | 8208a22 | 2011-07-25 17:32:17 -0400 | [diff] [blame] | 3579 | SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, dev) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 3580 | { |
| 3581 | return sys_mknodat(AT_FDCWD, filename, mode, dev); |
| 3582 | } |
| 3583 | |
Al Viro | 18bb1db | 2011-07-26 01:41:39 -0400 | [diff] [blame] | 3584 | int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3585 | { |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 3586 | int error = may_create(dir, dentry); |
Al Viro | 8de5277 | 2012-02-06 12:45:27 -0500 | [diff] [blame] | 3587 | unsigned max_links = dir->i_sb->s_max_links; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3588 | |
| 3589 | if (error) |
| 3590 | return error; |
| 3591 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 3592 | if (!dir->i_op->mkdir) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3593 | return -EPERM; |
| 3594 | |
| 3595 | mode &= (S_IRWXUGO|S_ISVTX); |
| 3596 | error = security_inode_mkdir(dir, dentry, mode); |
| 3597 | if (error) |
| 3598 | return error; |
| 3599 | |
Al Viro | 8de5277 | 2012-02-06 12:45:27 -0500 | [diff] [blame] | 3600 | if (max_links && dir->i_nlink >= max_links) |
| 3601 | return -EMLINK; |
| 3602 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3603 | error = dir->i_op->mkdir(dir, dentry, mode); |
Stephen Smalley | a74574a | 2005-09-09 13:01:44 -0700 | [diff] [blame] | 3604 | if (!error) |
Amy Griffis | f38aa94 | 2005-11-03 15:57:06 +0000 | [diff] [blame] | 3605 | fsnotify_mkdir(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3606 | return error; |
| 3607 | } |
Al Viro | 4d35950 | 2014-03-14 12:20:17 -0400 | [diff] [blame] | 3608 | EXPORT_SYMBOL(vfs_mkdir); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3609 | |
Al Viro | a218d0f | 2011-11-21 14:59:34 -0500 | [diff] [blame] | 3610 | SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3611 | { |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 3612 | struct dentry *dentry; |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3613 | struct path path; |
| 3614 | int error; |
Jeff Layton | b76d8b8 | 2012-12-20 16:04:09 -0500 | [diff] [blame] | 3615 | unsigned int lookup_flags = LOOKUP_DIRECTORY; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3616 | |
Jeff Layton | b76d8b8 | 2012-12-20 16:04:09 -0500 | [diff] [blame] | 3617 | retry: |
| 3618 | dentry = user_path_create(dfd, pathname, &path, lookup_flags); |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 3619 | if (IS_ERR(dentry)) |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3620 | return PTR_ERR(dentry); |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 3621 | |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3622 | if (!IS_POSIXACL(path.dentry->d_inode)) |
Al Viro | ce3b0f8 | 2009-03-29 19:08:22 -0400 | [diff] [blame] | 3623 | mode &= ~current_umask(); |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3624 | error = security_path_mkdir(&path, dentry, mode); |
Al Viro | a8104a9 | 2012-07-20 02:25:00 +0400 | [diff] [blame] | 3625 | if (!error) |
| 3626 | error = vfs_mkdir(path.dentry->d_inode, dentry, mode); |
Al Viro | 921a165 | 2012-07-20 01:15:31 +0400 | [diff] [blame] | 3627 | done_path_create(&path, dentry); |
Jeff Layton | b76d8b8 | 2012-12-20 16:04:09 -0500 | [diff] [blame] | 3628 | if (retry_estale(error, lookup_flags)) { |
| 3629 | lookup_flags |= LOOKUP_REVAL; |
| 3630 | goto retry; |
| 3631 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3632 | return error; |
| 3633 | } |
| 3634 | |
Al Viro | a218d0f | 2011-11-21 14:59:34 -0500 | [diff] [blame] | 3635 | SYSCALL_DEFINE2(mkdir, const char __user *, pathname, umode_t, mode) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 3636 | { |
| 3637 | return sys_mkdirat(AT_FDCWD, pathname, mode); |
| 3638 | } |
| 3639 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3640 | /* |
Sage Weil | a71905f | 2011-05-24 13:06:08 -0700 | [diff] [blame] | 3641 | * The dentry_unhash() helper will try to drop the dentry early: we |
J. Bruce Fields | c0d0259 | 2012-02-15 11:48:40 -0500 | [diff] [blame] | 3642 | * should have a usage count of 1 if we're the only user of this |
Sage Weil | a71905f | 2011-05-24 13:06:08 -0700 | [diff] [blame] | 3643 | * dentry, and if that is true (possibly after pruning the dcache), |
| 3644 | * then we drop the dentry now. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3645 | * |
| 3646 | * A low-level filesystem can, if it choses, legally |
| 3647 | * do a |
| 3648 | * |
| 3649 | * if (!d_unhashed(dentry)) |
| 3650 | * return -EBUSY; |
| 3651 | * |
| 3652 | * if it cannot handle the case of removing a directory |
| 3653 | * that is still in use by something else.. |
| 3654 | */ |
| 3655 | void dentry_unhash(struct dentry *dentry) |
| 3656 | { |
Vasily Averin | dc16842 | 2006-12-06 20:37:07 -0800 | [diff] [blame] | 3657 | shrink_dcache_parent(dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3658 | spin_lock(&dentry->d_lock); |
Waiman Long | 9847423 | 2013-08-28 18:24:59 -0700 | [diff] [blame] | 3659 | if (dentry->d_lockref.count == 1) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3660 | __d_drop(dentry); |
| 3661 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3662 | } |
Al Viro | 4d35950 | 2014-03-14 12:20:17 -0400 | [diff] [blame] | 3663 | EXPORT_SYMBOL(dentry_unhash); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3664 | |
| 3665 | int vfs_rmdir(struct inode *dir, struct dentry *dentry) |
| 3666 | { |
| 3667 | int error = may_delete(dir, dentry, 1); |
| 3668 | |
| 3669 | if (error) |
| 3670 | return error; |
| 3671 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 3672 | if (!dir->i_op->rmdir) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3673 | return -EPERM; |
| 3674 | |
Al Viro | 1d2ef59 | 2011-09-14 18:55:41 +0100 | [diff] [blame] | 3675 | dget(dentry); |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 3676 | mutex_lock(&dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3677 | |
Sage Weil | 912dbc1 | 2011-05-24 13:06:11 -0700 | [diff] [blame] | 3678 | error = -EBUSY; |
Eric W. Biederman | 7af1364 | 2013-10-04 19:15:13 -0700 | [diff] [blame] | 3679 | if (is_local_mountpoint(dentry)) |
Sage Weil | 912dbc1 | 2011-05-24 13:06:11 -0700 | [diff] [blame] | 3680 | goto out; |
| 3681 | |
| 3682 | error = security_inode_rmdir(dir, dentry); |
| 3683 | if (error) |
| 3684 | goto out; |
| 3685 | |
Sage Weil | 3cebde2 | 2011-05-29 21:20:59 -0700 | [diff] [blame] | 3686 | shrink_dcache_parent(dentry); |
Sage Weil | 912dbc1 | 2011-05-24 13:06:11 -0700 | [diff] [blame] | 3687 | error = dir->i_op->rmdir(dir, dentry); |
| 3688 | if (error) |
| 3689 | goto out; |
| 3690 | |
| 3691 | dentry->d_inode->i_flags |= S_DEAD; |
| 3692 | dont_mount(dentry); |
Eric W. Biederman | 8ed936b | 2013-10-01 18:33:48 -0700 | [diff] [blame] | 3693 | detach_mounts(dentry); |
Sage Weil | 912dbc1 | 2011-05-24 13:06:11 -0700 | [diff] [blame] | 3694 | |
| 3695 | out: |
| 3696 | mutex_unlock(&dentry->d_inode->i_mutex); |
Al Viro | 1d2ef59 | 2011-09-14 18:55:41 +0100 | [diff] [blame] | 3697 | dput(dentry); |
Sage Weil | 912dbc1 | 2011-05-24 13:06:11 -0700 | [diff] [blame] | 3698 | if (!error) |
| 3699 | d_delete(dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3700 | return error; |
| 3701 | } |
Al Viro | 4d35950 | 2014-03-14 12:20:17 -0400 | [diff] [blame] | 3702 | EXPORT_SYMBOL(vfs_rmdir); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3703 | |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 3704 | static long do_rmdir(int dfd, const char __user *pathname) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3705 | { |
| 3706 | int error = 0; |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 3707 | struct filename *name; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3708 | struct dentry *dentry; |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 3709 | struct path path; |
| 3710 | struct qstr last; |
| 3711 | int type; |
Jeff Layton | c6ee920 | 2012-12-20 16:28:33 -0500 | [diff] [blame] | 3712 | unsigned int lookup_flags = 0; |
| 3713 | retry: |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 3714 | name = user_path_parent(dfd, pathname, |
| 3715 | &path, &last, &type, lookup_flags); |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 3716 | if (IS_ERR(name)) |
| 3717 | return PTR_ERR(name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3718 | |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 3719 | switch (type) { |
OGAWA Hirofumi | 0612d9f | 2008-10-16 07:50:29 +0900 | [diff] [blame] | 3720 | case LAST_DOTDOT: |
| 3721 | error = -ENOTEMPTY; |
| 3722 | goto exit1; |
| 3723 | case LAST_DOT: |
| 3724 | error = -EINVAL; |
| 3725 | goto exit1; |
| 3726 | case LAST_ROOT: |
| 3727 | error = -EBUSY; |
| 3728 | goto exit1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3729 | } |
OGAWA Hirofumi | 0612d9f | 2008-10-16 07:50:29 +0900 | [diff] [blame] | 3730 | |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 3731 | error = mnt_want_write(path.mnt); |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 3732 | if (error) |
| 3733 | goto exit1; |
OGAWA Hirofumi | 0612d9f | 2008-10-16 07:50:29 +0900 | [diff] [blame] | 3734 | |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 3735 | mutex_lock_nested(&path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); |
| 3736 | dentry = __lookup_hash(&last, path.dentry, lookup_flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3737 | error = PTR_ERR(dentry); |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 3738 | if (IS_ERR(dentry)) |
| 3739 | goto exit2; |
Theodore Ts'o | e6bc45d | 2011-06-06 19:19:40 -0400 | [diff] [blame] | 3740 | if (!dentry->d_inode) { |
| 3741 | error = -ENOENT; |
| 3742 | goto exit3; |
| 3743 | } |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 3744 | error = security_path_rmdir(&path, dentry); |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 3745 | if (error) |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 3746 | goto exit3; |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 3747 | error = vfs_rmdir(path.dentry->d_inode, dentry); |
Dave Hansen | 0622753 | 2008-02-15 14:37:34 -0800 | [diff] [blame] | 3748 | exit3: |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 3749 | dput(dentry); |
| 3750 | exit2: |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 3751 | mutex_unlock(&path.dentry->d_inode->i_mutex); |
| 3752 | mnt_drop_write(path.mnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3753 | exit1: |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 3754 | path_put(&path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3755 | putname(name); |
Jeff Layton | c6ee920 | 2012-12-20 16:28:33 -0500 | [diff] [blame] | 3756 | if (retry_estale(error, lookup_flags)) { |
| 3757 | lookup_flags |= LOOKUP_REVAL; |
| 3758 | goto retry; |
| 3759 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3760 | return error; |
| 3761 | } |
| 3762 | |
Heiko Carstens | 3cdad42 | 2009-01-14 14:14:22 +0100 | [diff] [blame] | 3763 | SYSCALL_DEFINE1(rmdir, const char __user *, pathname) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 3764 | { |
| 3765 | return do_rmdir(AT_FDCWD, pathname); |
| 3766 | } |
| 3767 | |
J. Bruce Fields | b21996e | 2011-09-20 09:14:34 -0400 | [diff] [blame] | 3768 | /** |
| 3769 | * vfs_unlink - unlink a filesystem object |
| 3770 | * @dir: parent directory |
| 3771 | * @dentry: victim |
| 3772 | * @delegated_inode: returns victim inode, if the inode is delegated. |
| 3773 | * |
| 3774 | * The caller must hold dir->i_mutex. |
| 3775 | * |
| 3776 | * If vfs_unlink discovers a delegation, it will return -EWOULDBLOCK and |
| 3777 | * return a reference to the inode in delegated_inode. The caller |
| 3778 | * should then break the delegation on that inode and retry. Because |
| 3779 | * breaking a delegation may take a long time, the caller should drop |
| 3780 | * dir->i_mutex before doing so. |
| 3781 | * |
| 3782 | * Alternatively, a caller may pass NULL for delegated_inode. This may |
| 3783 | * be appropriate for callers that expect the underlying filesystem not |
| 3784 | * to be NFS exported. |
| 3785 | */ |
| 3786 | int vfs_unlink(struct inode *dir, struct dentry *dentry, struct inode **delegated_inode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3787 | { |
J. Bruce Fields | 9accbb9 | 2012-08-28 07:03:24 -0400 | [diff] [blame] | 3788 | struct inode *target = dentry->d_inode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3789 | int error = may_delete(dir, dentry, 0); |
| 3790 | |
| 3791 | if (error) |
| 3792 | return error; |
| 3793 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 3794 | if (!dir->i_op->unlink) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3795 | return -EPERM; |
| 3796 | |
J. Bruce Fields | 9accbb9 | 2012-08-28 07:03:24 -0400 | [diff] [blame] | 3797 | mutex_lock(&target->i_mutex); |
Eric W. Biederman | 8ed936b | 2013-10-01 18:33:48 -0700 | [diff] [blame] | 3798 | if (is_local_mountpoint(dentry)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3799 | error = -EBUSY; |
| 3800 | else { |
| 3801 | error = security_inode_unlink(dir, dentry); |
Al Viro | bec1052 | 2010-03-03 14:12:08 -0500 | [diff] [blame] | 3802 | if (!error) { |
J. Bruce Fields | 5a14696 | 2012-08-28 07:50:40 -0700 | [diff] [blame] | 3803 | error = try_break_deleg(target, delegated_inode); |
| 3804 | if (error) |
J. Bruce Fields | b21996e | 2011-09-20 09:14:34 -0400 | [diff] [blame] | 3805 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3806 | error = dir->i_op->unlink(dir, dentry); |
Eric W. Biederman | 8ed936b | 2013-10-01 18:33:48 -0700 | [diff] [blame] | 3807 | if (!error) { |
Al Viro | d83c49f | 2010-04-30 17:17:09 -0400 | [diff] [blame] | 3808 | dont_mount(dentry); |
Eric W. Biederman | 8ed936b | 2013-10-01 18:33:48 -0700 | [diff] [blame] | 3809 | detach_mounts(dentry); |
| 3810 | } |
Al Viro | bec1052 | 2010-03-03 14:12:08 -0500 | [diff] [blame] | 3811 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3812 | } |
J. Bruce Fields | b21996e | 2011-09-20 09:14:34 -0400 | [diff] [blame] | 3813 | out: |
J. Bruce Fields | 9accbb9 | 2012-08-28 07:03:24 -0400 | [diff] [blame] | 3814 | mutex_unlock(&target->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3815 | |
| 3816 | /* We don't d_delete() NFS sillyrenamed files--they still exist. */ |
| 3817 | if (!error && !(dentry->d_flags & DCACHE_NFSFS_RENAMED)) { |
J. Bruce Fields | 9accbb9 | 2012-08-28 07:03:24 -0400 | [diff] [blame] | 3818 | fsnotify_link_count(target); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3819 | d_delete(dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3820 | } |
Robert Love | 0eeca28 | 2005-07-12 17:06:03 -0400 | [diff] [blame] | 3821 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3822 | return error; |
| 3823 | } |
Al Viro | 4d35950 | 2014-03-14 12:20:17 -0400 | [diff] [blame] | 3824 | EXPORT_SYMBOL(vfs_unlink); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3825 | |
| 3826 | /* |
| 3827 | * Make sure that the actual truncation of the file will occur outside its |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 3828 | * directory's i_mutex. Truncate can take a long time if there is a lot of |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3829 | * writeout happening, and we don't want to prevent access to the directory |
| 3830 | * while waiting on the I/O. |
| 3831 | */ |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 3832 | static long do_unlinkat(int dfd, const char __user *pathname) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3833 | { |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 3834 | int error; |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 3835 | struct filename *name; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3836 | struct dentry *dentry; |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 3837 | struct path path; |
| 3838 | struct qstr last; |
| 3839 | int type; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3840 | struct inode *inode = NULL; |
J. Bruce Fields | b21996e | 2011-09-20 09:14:34 -0400 | [diff] [blame] | 3841 | struct inode *delegated_inode = NULL; |
Jeff Layton | 5d18f81 | 2012-12-20 16:38:04 -0500 | [diff] [blame] | 3842 | unsigned int lookup_flags = 0; |
| 3843 | retry: |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 3844 | name = user_path_parent(dfd, pathname, |
| 3845 | &path, &last, &type, lookup_flags); |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 3846 | if (IS_ERR(name)) |
| 3847 | return PTR_ERR(name); |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 3848 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3849 | error = -EISDIR; |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 3850 | if (type != LAST_NORM) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3851 | goto exit1; |
OGAWA Hirofumi | 0612d9f | 2008-10-16 07:50:29 +0900 | [diff] [blame] | 3852 | |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 3853 | error = mnt_want_write(path.mnt); |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 3854 | if (error) |
| 3855 | goto exit1; |
J. Bruce Fields | b21996e | 2011-09-20 09:14:34 -0400 | [diff] [blame] | 3856 | retry_deleg: |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 3857 | mutex_lock_nested(&path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); |
| 3858 | dentry = __lookup_hash(&last, path.dentry, lookup_flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3859 | error = PTR_ERR(dentry); |
| 3860 | if (!IS_ERR(dentry)) { |
| 3861 | /* Why not before? Because we want correct error value */ |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 3862 | if (last.name[last.len]) |
Török Edwin | 50338b8 | 2011-06-16 00:06:14 +0300 | [diff] [blame] | 3863 | goto slashes; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3864 | inode = dentry->d_inode; |
David Howells | b18825a | 2013-09-12 19:22:53 +0100 | [diff] [blame] | 3865 | if (d_is_negative(dentry)) |
Theodore Ts'o | e6bc45d | 2011-06-06 19:19:40 -0400 | [diff] [blame] | 3866 | goto slashes; |
| 3867 | ihold(inode); |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 3868 | error = security_path_unlink(&path, dentry); |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 3869 | if (error) |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 3870 | goto exit2; |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 3871 | error = vfs_unlink(path.dentry->d_inode, dentry, &delegated_inode); |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 3872 | exit2: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3873 | dput(dentry); |
| 3874 | } |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 3875 | mutex_unlock(&path.dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3876 | if (inode) |
| 3877 | iput(inode); /* truncate the inode here */ |
J. Bruce Fields | b21996e | 2011-09-20 09:14:34 -0400 | [diff] [blame] | 3878 | inode = NULL; |
| 3879 | if (delegated_inode) { |
J. Bruce Fields | 5a14696 | 2012-08-28 07:50:40 -0700 | [diff] [blame] | 3880 | error = break_deleg_wait(&delegated_inode); |
J. Bruce Fields | b21996e | 2011-09-20 09:14:34 -0400 | [diff] [blame] | 3881 | if (!error) |
| 3882 | goto retry_deleg; |
| 3883 | } |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 3884 | mnt_drop_write(path.mnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3885 | exit1: |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 3886 | path_put(&path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3887 | putname(name); |
Jeff Layton | 5d18f81 | 2012-12-20 16:38:04 -0500 | [diff] [blame] | 3888 | if (retry_estale(error, lookup_flags)) { |
| 3889 | lookup_flags |= LOOKUP_REVAL; |
| 3890 | inode = NULL; |
| 3891 | goto retry; |
| 3892 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3893 | return error; |
| 3894 | |
| 3895 | slashes: |
David Howells | b18825a | 2013-09-12 19:22:53 +0100 | [diff] [blame] | 3896 | if (d_is_negative(dentry)) |
| 3897 | error = -ENOENT; |
Miklos Szeredi | 44b1d53 | 2014-04-01 17:08:41 +0200 | [diff] [blame] | 3898 | else if (d_is_dir(dentry)) |
David Howells | b18825a | 2013-09-12 19:22:53 +0100 | [diff] [blame] | 3899 | error = -EISDIR; |
| 3900 | else |
| 3901 | error = -ENOTDIR; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3902 | goto exit2; |
| 3903 | } |
| 3904 | |
Heiko Carstens | 2e4d092 | 2009-01-14 14:14:31 +0100 | [diff] [blame] | 3905 | SYSCALL_DEFINE3(unlinkat, int, dfd, const char __user *, pathname, int, flag) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 3906 | { |
| 3907 | if ((flag & ~AT_REMOVEDIR) != 0) |
| 3908 | return -EINVAL; |
| 3909 | |
| 3910 | if (flag & AT_REMOVEDIR) |
| 3911 | return do_rmdir(dfd, pathname); |
| 3912 | |
| 3913 | return do_unlinkat(dfd, pathname); |
| 3914 | } |
| 3915 | |
Heiko Carstens | 3480b25 | 2009-01-14 14:14:16 +0100 | [diff] [blame] | 3916 | SYSCALL_DEFINE1(unlink, const char __user *, pathname) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 3917 | { |
| 3918 | return do_unlinkat(AT_FDCWD, pathname); |
| 3919 | } |
| 3920 | |
Miklos Szeredi | db2e747 | 2008-06-24 16:50:16 +0200 | [diff] [blame] | 3921 | int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3922 | { |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 3923 | int error = may_create(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3924 | |
| 3925 | if (error) |
| 3926 | return error; |
| 3927 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 3928 | if (!dir->i_op->symlink) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3929 | return -EPERM; |
| 3930 | |
| 3931 | error = security_inode_symlink(dir, dentry, oldname); |
| 3932 | if (error) |
| 3933 | return error; |
| 3934 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3935 | error = dir->i_op->symlink(dir, dentry, oldname); |
Stephen Smalley | a74574a | 2005-09-09 13:01:44 -0700 | [diff] [blame] | 3936 | if (!error) |
Amy Griffis | f38aa94 | 2005-11-03 15:57:06 +0000 | [diff] [blame] | 3937 | fsnotify_create(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3938 | return error; |
| 3939 | } |
Al Viro | 4d35950 | 2014-03-14 12:20:17 -0400 | [diff] [blame] | 3940 | EXPORT_SYMBOL(vfs_symlink); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3941 | |
Heiko Carstens | 2e4d092 | 2009-01-14 14:14:31 +0100 | [diff] [blame] | 3942 | SYSCALL_DEFINE3(symlinkat, const char __user *, oldname, |
| 3943 | int, newdfd, const char __user *, newname) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3944 | { |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 3945 | int error; |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 3946 | struct filename *from; |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 3947 | struct dentry *dentry; |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3948 | struct path path; |
Jeff Layton | f46d356 | 2012-12-11 12:10:08 -0500 | [diff] [blame] | 3949 | unsigned int lookup_flags = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3950 | |
| 3951 | from = getname(oldname); |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 3952 | if (IS_ERR(from)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3953 | return PTR_ERR(from); |
Jeff Layton | f46d356 | 2012-12-11 12:10:08 -0500 | [diff] [blame] | 3954 | retry: |
| 3955 | dentry = user_path_create(newdfd, newname, &path, lookup_flags); |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 3956 | error = PTR_ERR(dentry); |
| 3957 | if (IS_ERR(dentry)) |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3958 | goto out_putname; |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 3959 | |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 3960 | error = security_path_symlink(&path, dentry, from->name); |
Al Viro | a8104a9 | 2012-07-20 02:25:00 +0400 | [diff] [blame] | 3961 | if (!error) |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 3962 | error = vfs_symlink(path.dentry->d_inode, dentry, from->name); |
Al Viro | 921a165 | 2012-07-20 01:15:31 +0400 | [diff] [blame] | 3963 | done_path_create(&path, dentry); |
Jeff Layton | f46d356 | 2012-12-11 12:10:08 -0500 | [diff] [blame] | 3964 | if (retry_estale(error, lookup_flags)) { |
| 3965 | lookup_flags |= LOOKUP_REVAL; |
| 3966 | goto retry; |
| 3967 | } |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 3968 | out_putname: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3969 | putname(from); |
| 3970 | return error; |
| 3971 | } |
| 3972 | |
Heiko Carstens | 3480b25 | 2009-01-14 14:14:16 +0100 | [diff] [blame] | 3973 | SYSCALL_DEFINE2(symlink, const char __user *, oldname, const char __user *, newname) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 3974 | { |
| 3975 | return sys_symlinkat(oldname, AT_FDCWD, newname); |
| 3976 | } |
| 3977 | |
J. Bruce Fields | 146a859 | 2011-09-20 17:14:31 -0400 | [diff] [blame] | 3978 | /** |
| 3979 | * vfs_link - create a new link |
| 3980 | * @old_dentry: object to be linked |
| 3981 | * @dir: new parent |
| 3982 | * @new_dentry: where to create the new link |
| 3983 | * @delegated_inode: returns inode needing a delegation break |
| 3984 | * |
| 3985 | * The caller must hold dir->i_mutex |
| 3986 | * |
| 3987 | * If vfs_link discovers a delegation on the to-be-linked file in need |
| 3988 | * of breaking, it will return -EWOULDBLOCK and return a reference to the |
| 3989 | * inode in delegated_inode. The caller should then break the delegation |
| 3990 | * and retry. Because breaking a delegation may take a long time, the |
| 3991 | * caller should drop the i_mutex before doing so. |
| 3992 | * |
| 3993 | * Alternatively, a caller may pass NULL for delegated_inode. This may |
| 3994 | * be appropriate for callers that expect the underlying filesystem not |
| 3995 | * to be NFS exported. |
| 3996 | */ |
| 3997 | int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry, struct inode **delegated_inode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3998 | { |
| 3999 | struct inode *inode = old_dentry->d_inode; |
Al Viro | 8de5277 | 2012-02-06 12:45:27 -0500 | [diff] [blame] | 4000 | unsigned max_links = dir->i_sb->s_max_links; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4001 | int error; |
| 4002 | |
| 4003 | if (!inode) |
| 4004 | return -ENOENT; |
| 4005 | |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 4006 | error = may_create(dir, new_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4007 | if (error) |
| 4008 | return error; |
| 4009 | |
| 4010 | if (dir->i_sb != inode->i_sb) |
| 4011 | return -EXDEV; |
| 4012 | |
| 4013 | /* |
| 4014 | * A link to an append-only or immutable file cannot be created. |
| 4015 | */ |
| 4016 | if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) |
| 4017 | return -EPERM; |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 4018 | if (!dir->i_op->link) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4019 | return -EPERM; |
Tetsuo Handa | 7e79eed | 2008-06-24 16:50:15 +0200 | [diff] [blame] | 4020 | if (S_ISDIR(inode->i_mode)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4021 | return -EPERM; |
| 4022 | |
| 4023 | error = security_inode_link(old_dentry, dir, new_dentry); |
| 4024 | if (error) |
| 4025 | return error; |
| 4026 | |
Tetsuo Handa | 7e79eed | 2008-06-24 16:50:15 +0200 | [diff] [blame] | 4027 | mutex_lock(&inode->i_mutex); |
Aneesh Kumar K.V | aae8a97 | 2011-01-29 18:43:27 +0530 | [diff] [blame] | 4028 | /* Make sure we don't allow creating hardlink to an unlinked file */ |
Al Viro | f4e0c30 | 2013-06-11 08:34:36 +0400 | [diff] [blame] | 4029 | if (inode->i_nlink == 0 && !(inode->i_state & I_LINKABLE)) |
Aneesh Kumar K.V | aae8a97 | 2011-01-29 18:43:27 +0530 | [diff] [blame] | 4030 | error = -ENOENT; |
Al Viro | 8de5277 | 2012-02-06 12:45:27 -0500 | [diff] [blame] | 4031 | else if (max_links && inode->i_nlink >= max_links) |
| 4032 | error = -EMLINK; |
J. Bruce Fields | 146a859 | 2011-09-20 17:14:31 -0400 | [diff] [blame] | 4033 | else { |
| 4034 | error = try_break_deleg(inode, delegated_inode); |
| 4035 | if (!error) |
| 4036 | error = dir->i_op->link(old_dentry, dir, new_dentry); |
| 4037 | } |
Al Viro | f4e0c30 | 2013-06-11 08:34:36 +0400 | [diff] [blame] | 4038 | |
| 4039 | if (!error && (inode->i_state & I_LINKABLE)) { |
| 4040 | spin_lock(&inode->i_lock); |
| 4041 | inode->i_state &= ~I_LINKABLE; |
| 4042 | spin_unlock(&inode->i_lock); |
| 4043 | } |
Tetsuo Handa | 7e79eed | 2008-06-24 16:50:15 +0200 | [diff] [blame] | 4044 | mutex_unlock(&inode->i_mutex); |
Stephen Smalley | e31e14e | 2005-09-09 13:01:45 -0700 | [diff] [blame] | 4045 | if (!error) |
Tetsuo Handa | 7e79eed | 2008-06-24 16:50:15 +0200 | [diff] [blame] | 4046 | fsnotify_link(dir, inode, new_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4047 | return error; |
| 4048 | } |
Al Viro | 4d35950 | 2014-03-14 12:20:17 -0400 | [diff] [blame] | 4049 | EXPORT_SYMBOL(vfs_link); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4050 | |
| 4051 | /* |
| 4052 | * Hardlinks are often used in delicate situations. We avoid |
| 4053 | * security-related surprises by not following symlinks on the |
| 4054 | * newname. --KAB |
| 4055 | * |
| 4056 | * We don't follow them on the oldname either to be compatible |
| 4057 | * with linux 2.0, and to avoid hard-linking to directories |
| 4058 | * and other special files. --ADM |
| 4059 | */ |
Heiko Carstens | 2e4d092 | 2009-01-14 14:14:31 +0100 | [diff] [blame] | 4060 | SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname, |
| 4061 | int, newdfd, const char __user *, newname, int, flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4062 | { |
| 4063 | struct dentry *new_dentry; |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 4064 | struct path old_path, new_path; |
J. Bruce Fields | 146a859 | 2011-09-20 17:14:31 -0400 | [diff] [blame] | 4065 | struct inode *delegated_inode = NULL; |
Aneesh Kumar K.V | 11a7b37 | 2011-01-29 18:43:42 +0530 | [diff] [blame] | 4066 | int how = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4067 | int error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4068 | |
Aneesh Kumar K.V | 11a7b37 | 2011-01-29 18:43:42 +0530 | [diff] [blame] | 4069 | if ((flags & ~(AT_SYMLINK_FOLLOW | AT_EMPTY_PATH)) != 0) |
Ulrich Drepper | c04030e | 2006-02-24 13:04:21 -0800 | [diff] [blame] | 4070 | return -EINVAL; |
Aneesh Kumar K.V | 11a7b37 | 2011-01-29 18:43:42 +0530 | [diff] [blame] | 4071 | /* |
Linus Torvalds | f0cc6ff | 2013-08-28 09:18:05 -0700 | [diff] [blame] | 4072 | * To use null names we require CAP_DAC_READ_SEARCH |
| 4073 | * This ensures that not everyone will be able to create |
| 4074 | * handlink using the passed filedescriptor. |
Aneesh Kumar K.V | 11a7b37 | 2011-01-29 18:43:42 +0530 | [diff] [blame] | 4075 | */ |
Linus Torvalds | f0cc6ff | 2013-08-28 09:18:05 -0700 | [diff] [blame] | 4076 | if (flags & AT_EMPTY_PATH) { |
| 4077 | if (!capable(CAP_DAC_READ_SEARCH)) |
| 4078 | return -ENOENT; |
Aneesh Kumar K.V | 11a7b37 | 2011-01-29 18:43:42 +0530 | [diff] [blame] | 4079 | how = LOOKUP_EMPTY; |
Linus Torvalds | f0cc6ff | 2013-08-28 09:18:05 -0700 | [diff] [blame] | 4080 | } |
Ulrich Drepper | c04030e | 2006-02-24 13:04:21 -0800 | [diff] [blame] | 4081 | |
Aneesh Kumar K.V | 11a7b37 | 2011-01-29 18:43:42 +0530 | [diff] [blame] | 4082 | if (flags & AT_SYMLINK_FOLLOW) |
| 4083 | how |= LOOKUP_FOLLOW; |
Jeff Layton | 442e31c | 2012-12-20 16:15:38 -0500 | [diff] [blame] | 4084 | retry: |
Aneesh Kumar K.V | 11a7b37 | 2011-01-29 18:43:42 +0530 | [diff] [blame] | 4085 | error = user_path_at(olddfd, oldname, how, &old_path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4086 | if (error) |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 4087 | return error; |
| 4088 | |
Jeff Layton | 442e31c | 2012-12-20 16:15:38 -0500 | [diff] [blame] | 4089 | new_dentry = user_path_create(newdfd, newname, &new_path, |
| 4090 | (how & LOOKUP_REVAL)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4091 | error = PTR_ERR(new_dentry); |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 4092 | if (IS_ERR(new_dentry)) |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 4093 | goto out; |
| 4094 | |
| 4095 | error = -EXDEV; |
| 4096 | if (old_path.mnt != new_path.mnt) |
| 4097 | goto out_dput; |
Kees Cook | 800179c | 2012-07-25 17:29:07 -0700 | [diff] [blame] | 4098 | error = may_linkat(&old_path); |
| 4099 | if (unlikely(error)) |
| 4100 | goto out_dput; |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 4101 | error = security_path_link(old_path.dentry, &new_path, new_dentry); |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 4102 | if (error) |
Al Viro | a8104a9 | 2012-07-20 02:25:00 +0400 | [diff] [blame] | 4103 | goto out_dput; |
J. Bruce Fields | 146a859 | 2011-09-20 17:14:31 -0400 | [diff] [blame] | 4104 | error = vfs_link(old_path.dentry, new_path.dentry->d_inode, new_dentry, &delegated_inode); |
Dave Hansen | 75c3f29 | 2008-02-15 14:37:45 -0800 | [diff] [blame] | 4105 | out_dput: |
Al Viro | 921a165 | 2012-07-20 01:15:31 +0400 | [diff] [blame] | 4106 | done_path_create(&new_path, new_dentry); |
J. Bruce Fields | 146a859 | 2011-09-20 17:14:31 -0400 | [diff] [blame] | 4107 | if (delegated_inode) { |
| 4108 | error = break_deleg_wait(&delegated_inode); |
Oleg Drokin | d22e633 | 2014-01-31 15:41:58 -0500 | [diff] [blame] | 4109 | if (!error) { |
| 4110 | path_put(&old_path); |
J. Bruce Fields | 146a859 | 2011-09-20 17:14:31 -0400 | [diff] [blame] | 4111 | goto retry; |
Oleg Drokin | d22e633 | 2014-01-31 15:41:58 -0500 | [diff] [blame] | 4112 | } |
J. Bruce Fields | 146a859 | 2011-09-20 17:14:31 -0400 | [diff] [blame] | 4113 | } |
Jeff Layton | 442e31c | 2012-12-20 16:15:38 -0500 | [diff] [blame] | 4114 | if (retry_estale(error, how)) { |
Oleg Drokin | d22e633 | 2014-01-31 15:41:58 -0500 | [diff] [blame] | 4115 | path_put(&old_path); |
Jeff Layton | 442e31c | 2012-12-20 16:15:38 -0500 | [diff] [blame] | 4116 | how |= LOOKUP_REVAL; |
| 4117 | goto retry; |
| 4118 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4119 | out: |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 4120 | path_put(&old_path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4121 | |
| 4122 | return error; |
| 4123 | } |
| 4124 | |
Heiko Carstens | 3480b25 | 2009-01-14 14:14:16 +0100 | [diff] [blame] | 4125 | SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 4126 | { |
Ulrich Drepper | c04030e | 2006-02-24 13:04:21 -0800 | [diff] [blame] | 4127 | return sys_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0); |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 4128 | } |
| 4129 | |
Miklos Szeredi | bc27027 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4130 | /** |
| 4131 | * vfs_rename - rename a filesystem object |
| 4132 | * @old_dir: parent of source |
| 4133 | * @old_dentry: source |
| 4134 | * @new_dir: parent of destination |
| 4135 | * @new_dentry: destination |
| 4136 | * @delegated_inode: returns an inode needing a delegation break |
Miklos Szeredi | 520c8b1 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4137 | * @flags: rename flags |
Miklos Szeredi | bc27027 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4138 | * |
| 4139 | * The caller must hold multiple mutexes--see lock_rename()). |
| 4140 | * |
| 4141 | * If vfs_rename discovers a delegation in need of breaking at either |
| 4142 | * the source or destination, it will return -EWOULDBLOCK and return a |
| 4143 | * reference to the inode in delegated_inode. The caller should then |
| 4144 | * break the delegation and retry. Because breaking a delegation may |
| 4145 | * take a long time, the caller should drop all locks before doing |
| 4146 | * so. |
| 4147 | * |
| 4148 | * Alternatively, a caller may pass NULL for delegated_inode. This may |
| 4149 | * be appropriate for callers that expect the underlying filesystem not |
| 4150 | * to be NFS exported. |
| 4151 | * |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4152 | * The worst of all namespace operations - renaming directory. "Perverted" |
| 4153 | * doesn't even start to describe it. Somebody in UCB had a heck of a trip... |
| 4154 | * Problems: |
J. Bruce Fields | d03b29a | 2014-02-17 16:52:33 -0500 | [diff] [blame] | 4155 | * a) we can get into loop creation. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4156 | * b) race potential - two innocent renames can create a loop together. |
| 4157 | * That's where 4.4 screws up. Current fix: serialization on |
Arjan van de Ven | a11f3a0 | 2006-03-23 03:00:33 -0800 | [diff] [blame] | 4158 | * sb->s_vfs_rename_mutex. We might be more accurate, but that's another |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4159 | * story. |
J. Bruce Fields | 6cedba8 | 2012-03-05 11:40:41 -0500 | [diff] [blame] | 4160 | * c) we have to lock _four_ objects - parents and victim (if it exists), |
| 4161 | * and source (if it is not a directory). |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 4162 | * And that - after we got ->i_mutex on parents (until then we don't know |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4163 | * whether the target exists). Solution: try to be smart with locking |
| 4164 | * order for inodes. We rely on the fact that tree topology may change |
Arjan van de Ven | a11f3a0 | 2006-03-23 03:00:33 -0800 | [diff] [blame] | 4165 | * only under ->s_vfs_rename_mutex _and_ that parent of the object we |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4166 | * move will be locked. Thus we can rank directories by the tree |
| 4167 | * (ancestors first) and rank all non-directories after them. |
| 4168 | * That works since everybody except rename does "lock parent, lookup, |
Arjan van de Ven | a11f3a0 | 2006-03-23 03:00:33 -0800 | [diff] [blame] | 4169 | * lock child" and rename is under ->s_vfs_rename_mutex. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4170 | * HOWEVER, it relies on the assumption that any object with ->lookup() |
| 4171 | * has no more than 1 dentry. If "hybrid" objects will ever appear, |
| 4172 | * we'd better make sure that there's no link(2) for them. |
Sage Weil | e4eaac0 | 2011-05-24 13:06:07 -0700 | [diff] [blame] | 4173 | * d) conversion from fhandle to dentry may come in the wrong moment - when |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 4174 | * we are removing the target. Solution: we will have to grab ->i_mutex |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4175 | * in the fhandle_to_dentry code. [FIXME - current nfsfh.c relies on |
Adam Buchbinder | c41b20e | 2009-12-11 16:35:39 -0500 | [diff] [blame] | 4176 | * ->i_mutex on parents, which works but leads to some truly excessive |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4177 | * locking]. |
| 4178 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4179 | int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, |
J. Bruce Fields | 8e6d782 | 2011-09-20 16:59:58 -0400 | [diff] [blame] | 4180 | struct inode *new_dir, struct dentry *new_dentry, |
Miklos Szeredi | 520c8b1 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4181 | struct inode **delegated_inode, unsigned int flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4182 | { |
| 4183 | int error; |
Miklos Szeredi | bc27027 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4184 | bool is_dir = d_is_dir(old_dentry); |
Eric Paris | 59b0df2 | 2010-02-08 12:53:52 -0500 | [diff] [blame] | 4185 | const unsigned char *old_name; |
Miklos Szeredi | bc27027 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4186 | struct inode *source = old_dentry->d_inode; |
| 4187 | struct inode *target = new_dentry->d_inode; |
Miklos Szeredi | da1ce06 | 2014-04-01 17:08:43 +0200 | [diff] [blame] | 4188 | bool new_is_dir = false; |
| 4189 | unsigned max_links = new_dir->i_sb->s_max_links; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4190 | |
Miklos Szeredi | bc27027 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4191 | if (source == target) |
| 4192 | return 0; |
| 4193 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4194 | error = may_delete(old_dir, old_dentry, is_dir); |
| 4195 | if (error) |
| 4196 | return error; |
| 4197 | |
Miklos Szeredi | da1ce06 | 2014-04-01 17:08:43 +0200 | [diff] [blame] | 4198 | if (!target) { |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 4199 | error = may_create(new_dir, new_dentry); |
Miklos Szeredi | da1ce06 | 2014-04-01 17:08:43 +0200 | [diff] [blame] | 4200 | } else { |
| 4201 | new_is_dir = d_is_dir(new_dentry); |
| 4202 | |
| 4203 | if (!(flags & RENAME_EXCHANGE)) |
| 4204 | error = may_delete(new_dir, new_dentry, is_dir); |
| 4205 | else |
| 4206 | error = may_delete(new_dir, new_dentry, new_is_dir); |
| 4207 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4208 | if (error) |
| 4209 | return error; |
| 4210 | |
Miklos Szeredi | 7177a9c | 2014-07-23 15:15:30 +0200 | [diff] [blame] | 4211 | if (!old_dir->i_op->rename && !old_dir->i_op->rename2) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4212 | return -EPERM; |
| 4213 | |
Miklos Szeredi | 520c8b1 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4214 | if (flags && !old_dir->i_op->rename2) |
| 4215 | return -EINVAL; |
| 4216 | |
Miklos Szeredi | bc27027 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4217 | /* |
| 4218 | * If we are going to change the parent - check write permissions, |
| 4219 | * we'll need to flip '..'. |
| 4220 | */ |
Miklos Szeredi | da1ce06 | 2014-04-01 17:08:43 +0200 | [diff] [blame] | 4221 | if (new_dir != old_dir) { |
| 4222 | if (is_dir) { |
| 4223 | error = inode_permission(source, MAY_WRITE); |
| 4224 | if (error) |
| 4225 | return error; |
| 4226 | } |
| 4227 | if ((flags & RENAME_EXCHANGE) && new_is_dir) { |
| 4228 | error = inode_permission(target, MAY_WRITE); |
| 4229 | if (error) |
| 4230 | return error; |
| 4231 | } |
Miklos Szeredi | bc27027 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4232 | } |
Robert Love | 0eeca28 | 2005-07-12 17:06:03 -0400 | [diff] [blame] | 4233 | |
Miklos Szeredi | 0b3974e | 2014-04-01 17:08:43 +0200 | [diff] [blame] | 4234 | error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry, |
| 4235 | flags); |
Miklos Szeredi | bc27027 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4236 | if (error) |
| 4237 | return error; |
| 4238 | |
| 4239 | old_name = fsnotify_oldname_init(old_dentry->d_name.name); |
| 4240 | dget(new_dentry); |
Miklos Szeredi | da1ce06 | 2014-04-01 17:08:43 +0200 | [diff] [blame] | 4241 | if (!is_dir || (flags & RENAME_EXCHANGE)) |
Miklos Szeredi | bc27027 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4242 | lock_two_nondirectories(source, target); |
| 4243 | else if (target) |
| 4244 | mutex_lock(&target->i_mutex); |
| 4245 | |
| 4246 | error = -EBUSY; |
Eric W. Biederman | 7af1364 | 2013-10-04 19:15:13 -0700 | [diff] [blame] | 4247 | if (is_local_mountpoint(old_dentry) || is_local_mountpoint(new_dentry)) |
Miklos Szeredi | bc27027 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4248 | goto out; |
| 4249 | |
Miklos Szeredi | da1ce06 | 2014-04-01 17:08:43 +0200 | [diff] [blame] | 4250 | if (max_links && new_dir != old_dir) { |
Miklos Szeredi | bc27027 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4251 | error = -EMLINK; |
Miklos Szeredi | da1ce06 | 2014-04-01 17:08:43 +0200 | [diff] [blame] | 4252 | if (is_dir && !new_is_dir && new_dir->i_nlink >= max_links) |
Miklos Szeredi | bc27027 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4253 | goto out; |
Miklos Szeredi | da1ce06 | 2014-04-01 17:08:43 +0200 | [diff] [blame] | 4254 | if ((flags & RENAME_EXCHANGE) && !is_dir && new_is_dir && |
| 4255 | old_dir->i_nlink >= max_links) |
| 4256 | goto out; |
| 4257 | } |
| 4258 | if (is_dir && !(flags & RENAME_EXCHANGE) && target) |
| 4259 | shrink_dcache_parent(new_dentry); |
| 4260 | if (!is_dir) { |
Miklos Szeredi | bc27027 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4261 | error = try_break_deleg(source, delegated_inode); |
| 4262 | if (error) |
| 4263 | goto out; |
Miklos Szeredi | da1ce06 | 2014-04-01 17:08:43 +0200 | [diff] [blame] | 4264 | } |
| 4265 | if (target && !new_is_dir) { |
| 4266 | error = try_break_deleg(target, delegated_inode); |
| 4267 | if (error) |
| 4268 | goto out; |
Miklos Szeredi | bc27027 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4269 | } |
Miklos Szeredi | 7177a9c | 2014-07-23 15:15:30 +0200 | [diff] [blame] | 4270 | if (!old_dir->i_op->rename2) { |
Miklos Szeredi | 520c8b1 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4271 | error = old_dir->i_op->rename(old_dir, old_dentry, |
| 4272 | new_dir, new_dentry); |
| 4273 | } else { |
Miklos Szeredi | 7177a9c | 2014-07-23 15:15:30 +0200 | [diff] [blame] | 4274 | WARN_ON(old_dir->i_op->rename != NULL); |
Miklos Szeredi | 520c8b1 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4275 | error = old_dir->i_op->rename2(old_dir, old_dentry, |
| 4276 | new_dir, new_dentry, flags); |
| 4277 | } |
Miklos Szeredi | bc27027 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4278 | if (error) |
| 4279 | goto out; |
| 4280 | |
Miklos Szeredi | da1ce06 | 2014-04-01 17:08:43 +0200 | [diff] [blame] | 4281 | if (!(flags & RENAME_EXCHANGE) && target) { |
Miklos Szeredi | bc27027 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4282 | if (is_dir) |
| 4283 | target->i_flags |= S_DEAD; |
| 4284 | dont_mount(new_dentry); |
Eric W. Biederman | 8ed936b | 2013-10-01 18:33:48 -0700 | [diff] [blame] | 4285 | detach_mounts(new_dentry); |
Miklos Szeredi | bc27027 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4286 | } |
Miklos Szeredi | da1ce06 | 2014-04-01 17:08:43 +0200 | [diff] [blame] | 4287 | if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) { |
| 4288 | if (!(flags & RENAME_EXCHANGE)) |
| 4289 | d_move(old_dentry, new_dentry); |
| 4290 | else |
| 4291 | d_exchange(old_dentry, new_dentry); |
| 4292 | } |
Miklos Szeredi | bc27027 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4293 | out: |
Miklos Szeredi | da1ce06 | 2014-04-01 17:08:43 +0200 | [diff] [blame] | 4294 | if (!is_dir || (flags & RENAME_EXCHANGE)) |
Miklos Szeredi | bc27027 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4295 | unlock_two_nondirectories(source, target); |
| 4296 | else if (target) |
| 4297 | mutex_unlock(&target->i_mutex); |
| 4298 | dput(new_dentry); |
Miklos Szeredi | da1ce06 | 2014-04-01 17:08:43 +0200 | [diff] [blame] | 4299 | if (!error) { |
Al Viro | 123df29 | 2009-12-25 04:57:57 -0500 | [diff] [blame] | 4300 | fsnotify_move(old_dir, new_dir, old_name, is_dir, |
Miklos Szeredi | da1ce06 | 2014-04-01 17:08:43 +0200 | [diff] [blame] | 4301 | !(flags & RENAME_EXCHANGE) ? target : NULL, old_dentry); |
| 4302 | if (flags & RENAME_EXCHANGE) { |
| 4303 | fsnotify_move(new_dir, old_dir, old_dentry->d_name.name, |
| 4304 | new_is_dir, NULL, new_dentry); |
| 4305 | } |
| 4306 | } |
Robert Love | 0eeca28 | 2005-07-12 17:06:03 -0400 | [diff] [blame] | 4307 | fsnotify_oldname_free(old_name); |
| 4308 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4309 | return error; |
| 4310 | } |
Al Viro | 4d35950 | 2014-03-14 12:20:17 -0400 | [diff] [blame] | 4311 | EXPORT_SYMBOL(vfs_rename); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4312 | |
Miklos Szeredi | 520c8b1 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4313 | SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname, |
| 4314 | int, newdfd, const char __user *, newname, unsigned int, flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4315 | { |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 4316 | struct dentry *old_dentry, *new_dentry; |
| 4317 | struct dentry *trap; |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 4318 | struct path old_path, new_path; |
| 4319 | struct qstr old_last, new_last; |
| 4320 | int old_type, new_type; |
J. Bruce Fields | 8e6d782 | 2011-09-20 16:59:58 -0400 | [diff] [blame] | 4321 | struct inode *delegated_inode = NULL; |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 4322 | struct filename *from; |
| 4323 | struct filename *to; |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 4324 | unsigned int lookup_flags = 0, target_flags = LOOKUP_RENAME_TARGET; |
Jeff Layton | c6a9428 | 2012-12-11 12:10:10 -0500 | [diff] [blame] | 4325 | bool should_retry = false; |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 4326 | int error; |
Miklos Szeredi | 520c8b1 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4327 | |
Miklos Szeredi | 0d7a855 | 2014-10-24 00:14:37 +0200 | [diff] [blame] | 4328 | if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT)) |
Miklos Szeredi | da1ce06 | 2014-04-01 17:08:43 +0200 | [diff] [blame] | 4329 | return -EINVAL; |
| 4330 | |
Miklos Szeredi | 0d7a855 | 2014-10-24 00:14:37 +0200 | [diff] [blame] | 4331 | if ((flags & (RENAME_NOREPLACE | RENAME_WHITEOUT)) && |
| 4332 | (flags & RENAME_EXCHANGE)) |
Miklos Szeredi | 520c8b1 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4333 | return -EINVAL; |
| 4334 | |
Miklos Szeredi | 0d7a855 | 2014-10-24 00:14:37 +0200 | [diff] [blame] | 4335 | if ((flags & RENAME_WHITEOUT) && !capable(CAP_MKNOD)) |
| 4336 | return -EPERM; |
| 4337 | |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 4338 | if (flags & RENAME_EXCHANGE) |
| 4339 | target_flags = 0; |
| 4340 | |
Jeff Layton | c6a9428 | 2012-12-11 12:10:10 -0500 | [diff] [blame] | 4341 | retry: |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 4342 | from = user_path_parent(olddfd, oldname, |
| 4343 | &old_path, &old_last, &old_type, lookup_flags); |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 4344 | if (IS_ERR(from)) { |
| 4345 | error = PTR_ERR(from); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4346 | goto exit; |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 4347 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4348 | |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 4349 | to = user_path_parent(newdfd, newname, |
| 4350 | &new_path, &new_last, &new_type, lookup_flags); |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 4351 | if (IS_ERR(to)) { |
| 4352 | error = PTR_ERR(to); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4353 | goto exit1; |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 4354 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4355 | |
| 4356 | error = -EXDEV; |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 4357 | if (old_path.mnt != new_path.mnt) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4358 | goto exit2; |
| 4359 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4360 | error = -EBUSY; |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 4361 | if (old_type != LAST_NORM) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4362 | goto exit2; |
| 4363 | |
Miklos Szeredi | 0a7c393 | 2014-04-01 17:08:43 +0200 | [diff] [blame] | 4364 | if (flags & RENAME_NOREPLACE) |
| 4365 | error = -EEXIST; |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 4366 | if (new_type != LAST_NORM) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4367 | goto exit2; |
| 4368 | |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 4369 | error = mnt_want_write(old_path.mnt); |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 4370 | if (error) |
| 4371 | goto exit2; |
| 4372 | |
J. Bruce Fields | 8e6d782 | 2011-09-20 16:59:58 -0400 | [diff] [blame] | 4373 | retry_deleg: |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 4374 | trap = lock_rename(new_path.dentry, old_path.dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4375 | |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 4376 | old_dentry = __lookup_hash(&old_last, old_path.dentry, lookup_flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4377 | error = PTR_ERR(old_dentry); |
| 4378 | if (IS_ERR(old_dentry)) |
| 4379 | goto exit3; |
| 4380 | /* source must exist */ |
| 4381 | error = -ENOENT; |
David Howells | b18825a | 2013-09-12 19:22:53 +0100 | [diff] [blame] | 4382 | if (d_is_negative(old_dentry)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4383 | goto exit4; |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 4384 | new_dentry = __lookup_hash(&new_last, new_path.dentry, lookup_flags | target_flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4385 | error = PTR_ERR(new_dentry); |
| 4386 | if (IS_ERR(new_dentry)) |
| 4387 | goto exit4; |
Miklos Szeredi | 0a7c393 | 2014-04-01 17:08:43 +0200 | [diff] [blame] | 4388 | error = -EEXIST; |
| 4389 | if ((flags & RENAME_NOREPLACE) && d_is_positive(new_dentry)) |
| 4390 | goto exit5; |
Miklos Szeredi | da1ce06 | 2014-04-01 17:08:43 +0200 | [diff] [blame] | 4391 | if (flags & RENAME_EXCHANGE) { |
| 4392 | error = -ENOENT; |
| 4393 | if (d_is_negative(new_dentry)) |
| 4394 | goto exit5; |
| 4395 | |
| 4396 | if (!d_is_dir(new_dentry)) { |
| 4397 | error = -ENOTDIR; |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 4398 | if (new_last.name[new_last.len]) |
Miklos Szeredi | da1ce06 | 2014-04-01 17:08:43 +0200 | [diff] [blame] | 4399 | goto exit5; |
| 4400 | } |
| 4401 | } |
Miklos Szeredi | 0a7c393 | 2014-04-01 17:08:43 +0200 | [diff] [blame] | 4402 | /* unless the source is a directory trailing slashes give -ENOTDIR */ |
| 4403 | if (!d_is_dir(old_dentry)) { |
| 4404 | error = -ENOTDIR; |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 4405 | if (old_last.name[old_last.len]) |
Miklos Szeredi | 0a7c393 | 2014-04-01 17:08:43 +0200 | [diff] [blame] | 4406 | goto exit5; |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 4407 | if (!(flags & RENAME_EXCHANGE) && new_last.name[new_last.len]) |
Miklos Szeredi | 0a7c393 | 2014-04-01 17:08:43 +0200 | [diff] [blame] | 4408 | goto exit5; |
| 4409 | } |
| 4410 | /* source should not be ancestor of target */ |
| 4411 | error = -EINVAL; |
| 4412 | if (old_dentry == trap) |
| 4413 | goto exit5; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4414 | /* target should not be an ancestor of source */ |
Miklos Szeredi | da1ce06 | 2014-04-01 17:08:43 +0200 | [diff] [blame] | 4415 | if (!(flags & RENAME_EXCHANGE)) |
| 4416 | error = -ENOTEMPTY; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4417 | if (new_dentry == trap) |
| 4418 | goto exit5; |
| 4419 | |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 4420 | error = security_path_rename(&old_path, old_dentry, |
| 4421 | &new_path, new_dentry, flags); |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 4422 | if (error) |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 4423 | goto exit5; |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 4424 | error = vfs_rename(old_path.dentry->d_inode, old_dentry, |
| 4425 | new_path.dentry->d_inode, new_dentry, |
Miklos Szeredi | 520c8b1 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4426 | &delegated_inode, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4427 | exit5: |
| 4428 | dput(new_dentry); |
| 4429 | exit4: |
| 4430 | dput(old_dentry); |
| 4431 | exit3: |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 4432 | unlock_rename(new_path.dentry, old_path.dentry); |
J. Bruce Fields | 8e6d782 | 2011-09-20 16:59:58 -0400 | [diff] [blame] | 4433 | if (delegated_inode) { |
| 4434 | error = break_deleg_wait(&delegated_inode); |
| 4435 | if (!error) |
| 4436 | goto retry_deleg; |
| 4437 | } |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 4438 | mnt_drop_write(old_path.mnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4439 | exit2: |
Jeff Layton | c6a9428 | 2012-12-11 12:10:10 -0500 | [diff] [blame] | 4440 | if (retry_estale(error, lookup_flags)) |
| 4441 | should_retry = true; |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 4442 | path_put(&new_path); |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 4443 | putname(to); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4444 | exit1: |
Al Viro | f5beed7 | 2015-04-30 16:09:11 -0400 | [diff] [blame] | 4445 | path_put(&old_path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4446 | putname(from); |
Jeff Layton | c6a9428 | 2012-12-11 12:10:10 -0500 | [diff] [blame] | 4447 | if (should_retry) { |
| 4448 | should_retry = false; |
| 4449 | lookup_flags |= LOOKUP_REVAL; |
| 4450 | goto retry; |
| 4451 | } |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 4452 | exit: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4453 | return error; |
| 4454 | } |
| 4455 | |
Miklos Szeredi | 520c8b1 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4456 | SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname, |
| 4457 | int, newdfd, const char __user *, newname) |
| 4458 | { |
| 4459 | return sys_renameat2(olddfd, oldname, newdfd, newname, 0); |
| 4460 | } |
| 4461 | |
Heiko Carstens | a26eab2 | 2009-01-14 14:14:17 +0100 | [diff] [blame] | 4462 | SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newname) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 4463 | { |
Miklos Szeredi | 520c8b1 | 2014-04-01 17:08:42 +0200 | [diff] [blame] | 4464 | return sys_renameat2(AT_FDCWD, oldname, AT_FDCWD, newname, 0); |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 4465 | } |
| 4466 | |
Miklos Szeredi | 787fb6b | 2014-10-24 00:14:36 +0200 | [diff] [blame] | 4467 | int vfs_whiteout(struct inode *dir, struct dentry *dentry) |
| 4468 | { |
| 4469 | int error = may_create(dir, dentry); |
| 4470 | if (error) |
| 4471 | return error; |
| 4472 | |
| 4473 | if (!dir->i_op->mknod) |
| 4474 | return -EPERM; |
| 4475 | |
| 4476 | return dir->i_op->mknod(dir, dentry, |
| 4477 | S_IFCHR | WHITEOUT_MODE, WHITEOUT_DEV); |
| 4478 | } |
| 4479 | EXPORT_SYMBOL(vfs_whiteout); |
| 4480 | |
Al Viro | 5d826c8 | 2014-03-14 13:42:45 -0400 | [diff] [blame] | 4481 | int readlink_copy(char __user *buffer, int buflen, const char *link) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4482 | { |
Al Viro | 5d826c8 | 2014-03-14 13:42:45 -0400 | [diff] [blame] | 4483 | int len = PTR_ERR(link); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4484 | if (IS_ERR(link)) |
| 4485 | goto out; |
| 4486 | |
| 4487 | len = strlen(link); |
| 4488 | if (len > (unsigned) buflen) |
| 4489 | len = buflen; |
| 4490 | if (copy_to_user(buffer, link, len)) |
| 4491 | len = -EFAULT; |
| 4492 | out: |
| 4493 | return len; |
| 4494 | } |
Al Viro | 5d826c8 | 2014-03-14 13:42:45 -0400 | [diff] [blame] | 4495 | EXPORT_SYMBOL(readlink_copy); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4496 | |
| 4497 | /* |
| 4498 | * A helper for ->readlink(). This should be used *ONLY* for symlinks that |
| 4499 | * have ->follow_link() touching nd only in nd_set_link(). Using (or not |
| 4500 | * using) it for any given inode is up to filesystem. |
| 4501 | */ |
| 4502 | int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen) |
| 4503 | { |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 4504 | void *cookie; |
Al Viro | 5f2c417 | 2015-05-07 11:14:26 -0400 | [diff] [blame] | 4505 | struct inode *inode = d_inode(dentry); |
| 4506 | const char *link = inode->i_link; |
Marcin Slusarz | 694a176 | 2008-06-09 16:40:37 -0700 | [diff] [blame] | 4507 | int res; |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 4508 | |
Al Viro | d4dee48 | 2015-04-30 20:08:02 -0400 | [diff] [blame] | 4509 | if (!link) { |
Al Viro | 5f2c417 | 2015-05-07 11:14:26 -0400 | [diff] [blame] | 4510 | link = inode->i_op->follow_link(dentry, &cookie); |
Al Viro | d4dee48 | 2015-04-30 20:08:02 -0400 | [diff] [blame] | 4511 | if (IS_ERR(link)) |
| 4512 | return PTR_ERR(link); |
| 4513 | } |
Al Viro | 680baac | 2015-05-02 13:32:22 -0400 | [diff] [blame] | 4514 | res = readlink_copy(buffer, buflen, link); |
Al Viro | 5f2c417 | 2015-05-07 11:14:26 -0400 | [diff] [blame] | 4515 | if (inode->i_op->put_link) |
| 4516 | inode->i_op->put_link(inode, cookie); |
Marcin Slusarz | 694a176 | 2008-06-09 16:40:37 -0700 | [diff] [blame] | 4517 | return res; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4518 | } |
Al Viro | 4d35950 | 2014-03-14 12:20:17 -0400 | [diff] [blame] | 4519 | EXPORT_SYMBOL(generic_readlink); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4520 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4521 | /* get the link contents into pagecache */ |
| 4522 | static char *page_getlink(struct dentry * dentry, struct page **ppage) |
| 4523 | { |
Duane Griffin | ebd09ab | 2008-12-19 20:47:12 +0000 | [diff] [blame] | 4524 | char *kaddr; |
| 4525 | struct page *page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4526 | struct address_space *mapping = dentry->d_inode->i_mapping; |
Pekka Enberg | 090d2b1 | 2006-06-23 02:05:08 -0700 | [diff] [blame] | 4527 | page = read_mapping_page(mapping, 0, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4528 | if (IS_ERR(page)) |
Nick Piggin | 6fe6900 | 2007-05-06 14:49:04 -0700 | [diff] [blame] | 4529 | return (char*)page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4530 | *ppage = page; |
Duane Griffin | ebd09ab | 2008-12-19 20:47:12 +0000 | [diff] [blame] | 4531 | kaddr = kmap(page); |
| 4532 | nd_terminate_link(kaddr, dentry->d_inode->i_size, PAGE_SIZE - 1); |
| 4533 | return kaddr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4534 | } |
| 4535 | |
| 4536 | int page_readlink(struct dentry *dentry, char __user *buffer, int buflen) |
| 4537 | { |
| 4538 | struct page *page = NULL; |
Al Viro | 5d826c8 | 2014-03-14 13:42:45 -0400 | [diff] [blame] | 4539 | int res = readlink_copy(buffer, buflen, page_getlink(dentry, &page)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4540 | if (page) { |
| 4541 | kunmap(page); |
| 4542 | page_cache_release(page); |
| 4543 | } |
| 4544 | return res; |
| 4545 | } |
Al Viro | 4d35950 | 2014-03-14 12:20:17 -0400 | [diff] [blame] | 4546 | EXPORT_SYMBOL(page_readlink); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4547 | |
Al Viro | 6e77137 | 2015-05-02 13:37:52 -0400 | [diff] [blame] | 4548 | const char *page_follow_link_light(struct dentry *dentry, void **cookie) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4549 | { |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 4550 | struct page *page = NULL; |
Al Viro | 680baac | 2015-05-02 13:32:22 -0400 | [diff] [blame] | 4551 | char *res = page_getlink(dentry, &page); |
| 4552 | if (!IS_ERR(res)) |
| 4553 | *cookie = page; |
| 4554 | return res; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4555 | } |
Al Viro | 4d35950 | 2014-03-14 12:20:17 -0400 | [diff] [blame] | 4556 | EXPORT_SYMBOL(page_follow_link_light); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4557 | |
Al Viro | 5f2c417 | 2015-05-07 11:14:26 -0400 | [diff] [blame] | 4558 | void page_put_link(struct inode *unused, void *cookie) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4559 | { |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 4560 | struct page *page = cookie; |
Al Viro | 680baac | 2015-05-02 13:32:22 -0400 | [diff] [blame] | 4561 | kunmap(page); |
| 4562 | page_cache_release(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4563 | } |
Al Viro | 4d35950 | 2014-03-14 12:20:17 -0400 | [diff] [blame] | 4564 | EXPORT_SYMBOL(page_put_link); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4565 | |
Nick Piggin | 54566b2 | 2009-01-04 12:00:53 -0800 | [diff] [blame] | 4566 | /* |
| 4567 | * The nofs argument instructs pagecache_write_begin to pass AOP_FLAG_NOFS |
| 4568 | */ |
| 4569 | int __page_symlink(struct inode *inode, const char *symname, int len, int nofs) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4570 | { |
| 4571 | struct address_space *mapping = inode->i_mapping; |
Kirill Korotaev | 0adb25d | 2006-03-11 03:27:13 -0800 | [diff] [blame] | 4572 | struct page *page; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 4573 | void *fsdata; |
Dmitriy Monakhov | beb497a | 2007-02-16 01:27:18 -0800 | [diff] [blame] | 4574 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4575 | char *kaddr; |
Nick Piggin | 54566b2 | 2009-01-04 12:00:53 -0800 | [diff] [blame] | 4576 | unsigned int flags = AOP_FLAG_UNINTERRUPTIBLE; |
| 4577 | if (nofs) |
| 4578 | flags |= AOP_FLAG_NOFS; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4579 | |
NeilBrown | 7e53cac | 2006-03-25 03:07:57 -0800 | [diff] [blame] | 4580 | retry: |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 4581 | err = pagecache_write_begin(NULL, mapping, 0, len-1, |
Nick Piggin | 54566b2 | 2009-01-04 12:00:53 -0800 | [diff] [blame] | 4582 | flags, &page, &fsdata); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4583 | if (err) |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 4584 | goto fail; |
| 4585 | |
Cong Wang | e8e3c3d | 2011-11-25 23:14:27 +0800 | [diff] [blame] | 4586 | kaddr = kmap_atomic(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4587 | memcpy(kaddr, symname, len-1); |
Cong Wang | e8e3c3d | 2011-11-25 23:14:27 +0800 | [diff] [blame] | 4588 | kunmap_atomic(kaddr); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 4589 | |
| 4590 | err = pagecache_write_end(NULL, mapping, 0, len-1, len-1, |
| 4591 | page, fsdata); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4592 | if (err < 0) |
| 4593 | goto fail; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 4594 | if (err < len-1) |
| 4595 | goto retry; |
| 4596 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4597 | mark_inode_dirty(inode); |
| 4598 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4599 | fail: |
| 4600 | return err; |
| 4601 | } |
Al Viro | 4d35950 | 2014-03-14 12:20:17 -0400 | [diff] [blame] | 4602 | EXPORT_SYMBOL(__page_symlink); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4603 | |
Kirill Korotaev | 0adb25d | 2006-03-11 03:27:13 -0800 | [diff] [blame] | 4604 | int page_symlink(struct inode *inode, const char *symname, int len) |
| 4605 | { |
| 4606 | return __page_symlink(inode, symname, len, |
Michal Hocko | c62d255 | 2015-11-06 16:28:49 -0800 | [diff] [blame] | 4607 | !mapping_gfp_constraint(inode->i_mapping, __GFP_FS)); |
Kirill Korotaev | 0adb25d | 2006-03-11 03:27:13 -0800 | [diff] [blame] | 4608 | } |
Al Viro | 4d35950 | 2014-03-14 12:20:17 -0400 | [diff] [blame] | 4609 | EXPORT_SYMBOL(page_symlink); |
Kirill Korotaev | 0adb25d | 2006-03-11 03:27:13 -0800 | [diff] [blame] | 4610 | |
Arjan van de Ven | 92e1d5b | 2007-02-12 00:55:39 -0800 | [diff] [blame] | 4611 | const struct inode_operations page_symlink_inode_operations = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4612 | .readlink = generic_readlink, |
| 4613 | .follow_link = page_follow_link_light, |
| 4614 | .put_link = page_put_link, |
| 4615 | }; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4616 | EXPORT_SYMBOL(page_symlink_inode_operations); |