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 | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 37 | #include <asm/uaccess.h> |
| 38 | |
Eric Paris | e81e3f4 | 2009-12-04 15:47:36 -0500 | [diff] [blame] | 39 | #include "internal.h" |
Al Viro | c710536 | 2011-11-24 18:22:03 -0500 | [diff] [blame] | 40 | #include "mount.h" |
Eric Paris | e81e3f4 | 2009-12-04 15:47:36 -0500 | [diff] [blame] | 41 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 42 | /* [Feb-1997 T. Schoebel-Theuer] |
| 43 | * Fundamental changes in the pathname lookup mechanisms (namei) |
| 44 | * were necessary because of omirr. The reason is that omirr needs |
| 45 | * to know the _real_ pathname, not the user-supplied one, in case |
| 46 | * of symlinks (and also when transname replacements occur). |
| 47 | * |
| 48 | * The new code replaces the old recursive symlink resolution with |
| 49 | * an iterative one (in case of non-nested symlink chains). It does |
| 50 | * this with calls to <fs>_follow_link(). |
| 51 | * As a side effect, dir_namei(), _namei() and follow_link() are now |
| 52 | * replaced with a single function lookup_dentry() that can handle all |
| 53 | * the special cases of the former code. |
| 54 | * |
| 55 | * With the new dcache, the pathname is stored at each inode, at least as |
| 56 | * long as the refcount of the inode is positive. As a side effect, the |
| 57 | * size of the dcache depends on the inode cache and thus is dynamic. |
| 58 | * |
| 59 | * [29-Apr-1998 C. Scott Ananian] Updated above description of symlink |
| 60 | * resolution to correspond with current state of the code. |
| 61 | * |
| 62 | * Note that the symlink resolution is not *completely* iterative. |
| 63 | * There is still a significant amount of tail- and mid- recursion in |
| 64 | * the algorithm. Also, note that <fs>_readlink() is not used in |
| 65 | * lookup_dentry(): lookup_dentry() on the result of <fs>_readlink() |
| 66 | * may return different results than <fs>_follow_link(). Many virtual |
| 67 | * filesystems (including /proc) exhibit this behavior. |
| 68 | */ |
| 69 | |
| 70 | /* [24-Feb-97 T. Schoebel-Theuer] Side effects caused by new implementation: |
| 71 | * New symlink semantics: when open() is called with flags O_CREAT | O_EXCL |
| 72 | * and the name already exists in form of a symlink, try to create the new |
| 73 | * name indicated by the symlink. The old code always complained that the |
| 74 | * name already exists, due to not following the symlink even if its target |
| 75 | * is nonexistent. The new semantics affects also mknod() and link() when |
Lucas De Marchi | 25985ed | 2011-03-30 22:57:33 -0300 | [diff] [blame] | 76 | * the name is a symlink pointing to a non-existent name. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 77 | * |
| 78 | * I don't know which semantics is the right one, since I have no access |
| 79 | * to standards. But I found by trial that HP-UX 9.0 has the full "new" |
| 80 | * semantics implemented, while SunOS 4.1.1 and Solaris (SunOS 5.4) have the |
| 81 | * "old" one. Personally, I think the new semantics is much more logical. |
| 82 | * Note that "ln old new" where "new" is a symlink pointing to a non-existing |
| 83 | * file does succeed in both HP-UX and SunOs, but not in Solaris |
| 84 | * and in the old Linux semantics. |
| 85 | */ |
| 86 | |
| 87 | /* [16-Dec-97 Kevin Buhr] For security reasons, we change some symlink |
| 88 | * semantics. See the comments in "open_namei" and "do_link" below. |
| 89 | * |
| 90 | * [10-Sep-98 Alan Modra] Another symlink change. |
| 91 | */ |
| 92 | |
| 93 | /* [Feb-Apr 2000 AV] Complete rewrite. Rules for symlinks: |
| 94 | * inside the path - always follow. |
| 95 | * in the last component in creation/removal/renaming - never follow. |
| 96 | * if LOOKUP_FOLLOW passed - follow. |
| 97 | * if the pathname has trailing slashes - follow. |
| 98 | * otherwise - don't follow. |
| 99 | * (applied in that order). |
| 100 | * |
| 101 | * [Jun 2000 AV] Inconsistent behaviour of open() in case if flags==O_CREAT |
| 102 | * restored for 2.4. This is the last surviving part of old 4.2BSD bug. |
| 103 | * During the 2.4 we need to fix the userland stuff depending on it - |
| 104 | * hopefully we will be able to get rid of that wart in 2.5. So far only |
| 105 | * XEmacs seems to be relying on it... |
| 106 | */ |
| 107 | /* |
| 108 | * [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] | 109 | * 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] | 110 | * any extra contention... |
| 111 | */ |
| 112 | |
| 113 | /* In order to reduce some races, while at the same time doing additional |
| 114 | * checking and hopefully speeding things up, we copy filenames to the |
| 115 | * kernel data space before using them.. |
| 116 | * |
| 117 | * POSIX.1 2.4: an empty pathname is invalid (ENOENT). |
| 118 | * PATH_MAX includes the nul terminator --RR. |
| 119 | */ |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 120 | void final_putname(struct filename *name) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 121 | { |
Jeff Layton | 7950e38 | 2012-10-10 16:43:13 -0400 | [diff] [blame] | 122 | if (name->separate) { |
| 123 | __putname(name->name); |
| 124 | kfree(name); |
| 125 | } else { |
| 126 | __putname(name); |
| 127 | } |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 128 | } |
| 129 | |
Jeff Layton | 7950e38 | 2012-10-10 16:43:13 -0400 | [diff] [blame] | 130 | #define EMBEDDED_NAME_MAX (PATH_MAX - sizeof(struct filename)) |
| 131 | |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 132 | static struct filename * |
| 133 | getname_flags(const char __user *filename, int flags, int *empty) |
| 134 | { |
| 135 | struct filename *result, *err; |
Linus Torvalds | 3f9f0aa | 2012-04-28 14:38:32 -0700 | [diff] [blame] | 136 | int len; |
Jeff Layton | 7950e38 | 2012-10-10 16:43:13 -0400 | [diff] [blame] | 137 | long max; |
| 138 | char *kname; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 139 | |
Jeff Layton | 7ac8626 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 140 | result = audit_reusename(filename); |
| 141 | if (result) |
| 142 | return result; |
| 143 | |
Jeff Layton | 7950e38 | 2012-10-10 16:43:13 -0400 | [diff] [blame] | 144 | result = __getname(); |
Linus Torvalds | 3f9f0aa | 2012-04-28 14:38:32 -0700 | [diff] [blame] | 145 | if (unlikely(!result)) |
Eric Paris | 4043cde | 2012-01-03 14:23:08 -0500 | [diff] [blame] | 146 | return ERR_PTR(-ENOMEM); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 147 | |
Jeff Layton | 7950e38 | 2012-10-10 16:43:13 -0400 | [diff] [blame] | 148 | /* |
| 149 | * First, try to embed the struct filename inside the names_cache |
| 150 | * allocation |
| 151 | */ |
| 152 | kname = (char *)result + sizeof(*result); |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 153 | result->name = kname; |
Jeff Layton | 7950e38 | 2012-10-10 16:43:13 -0400 | [diff] [blame] | 154 | result->separate = false; |
| 155 | max = EMBEDDED_NAME_MAX; |
| 156 | |
| 157 | recopy: |
| 158 | len = strncpy_from_user(kname, filename, max); |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 159 | if (unlikely(len < 0)) { |
| 160 | err = ERR_PTR(len); |
Linus Torvalds | 3f9f0aa | 2012-04-28 14:38:32 -0700 | [diff] [blame] | 161 | goto error; |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 162 | } |
Linus Torvalds | 3f9f0aa | 2012-04-28 14:38:32 -0700 | [diff] [blame] | 163 | |
Jeff Layton | 7950e38 | 2012-10-10 16:43:13 -0400 | [diff] [blame] | 164 | /* |
| 165 | * Uh-oh. We have a name that's approaching PATH_MAX. Allocate a |
| 166 | * separate struct filename so we can dedicate the entire |
| 167 | * names_cache allocation for the pathname, and re-do the copy from |
| 168 | * userland. |
| 169 | */ |
| 170 | if (len == EMBEDDED_NAME_MAX && max == EMBEDDED_NAME_MAX) { |
| 171 | kname = (char *)result; |
| 172 | |
| 173 | result = kzalloc(sizeof(*result), GFP_KERNEL); |
| 174 | if (!result) { |
| 175 | err = ERR_PTR(-ENOMEM); |
| 176 | result = (struct filename *)kname; |
| 177 | goto error; |
| 178 | } |
| 179 | result->name = kname; |
| 180 | result->separate = true; |
| 181 | max = PATH_MAX; |
| 182 | goto recopy; |
| 183 | } |
| 184 | |
Linus Torvalds | 3f9f0aa | 2012-04-28 14:38:32 -0700 | [diff] [blame] | 185 | /* The empty path is special. */ |
| 186 | if (unlikely(!len)) { |
| 187 | if (empty) |
Eric Paris | 4043cde | 2012-01-03 14:23:08 -0500 | [diff] [blame] | 188 | *empty = 1; |
Linus Torvalds | 3f9f0aa | 2012-04-28 14:38:32 -0700 | [diff] [blame] | 189 | err = ERR_PTR(-ENOENT); |
| 190 | if (!(flags & LOOKUP_EMPTY)) |
| 191 | goto error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 192 | } |
Linus Torvalds | 3f9f0aa | 2012-04-28 14:38:32 -0700 | [diff] [blame] | 193 | |
| 194 | err = ERR_PTR(-ENAMETOOLONG); |
Jeff Layton | 7950e38 | 2012-10-10 16:43:13 -0400 | [diff] [blame] | 195 | if (unlikely(len >= PATH_MAX)) |
| 196 | goto error; |
| 197 | |
| 198 | result->uptr = filename; |
| 199 | audit_getname(result); |
| 200 | return result; |
Linus Torvalds | 3f9f0aa | 2012-04-28 14:38:32 -0700 | [diff] [blame] | 201 | |
| 202 | error: |
Jeff Layton | 7950e38 | 2012-10-10 16:43:13 -0400 | [diff] [blame] | 203 | final_putname(result); |
Linus Torvalds | 3f9f0aa | 2012-04-28 14:38:32 -0700 | [diff] [blame] | 204 | return err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 205 | } |
| 206 | |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 207 | struct filename * |
| 208 | getname(const char __user * filename) |
Al Viro | f52e0c1 | 2011-03-14 18:56:51 -0400 | [diff] [blame] | 209 | { |
Linus Torvalds | f7493e5 | 2012-03-22 16:10:40 -0700 | [diff] [blame] | 210 | return getname_flags(filename, 0, NULL); |
Al Viro | f52e0c1 | 2011-03-14 18:56:51 -0400 | [diff] [blame] | 211 | } |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 212 | EXPORT_SYMBOL(getname); |
Al Viro | f52e0c1 | 2011-03-14 18:56:51 -0400 | [diff] [blame] | 213 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 214 | #ifdef CONFIG_AUDITSYSCALL |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 215 | void putname(struct filename *name) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 216 | { |
Al Viro | 5ac3a9c | 2006-07-16 06:38:45 -0400 | [diff] [blame] | 217 | if (unlikely(!audit_dummy_context())) |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 218 | return audit_putname(name); |
| 219 | final_putname(name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 220 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 221 | #endif |
| 222 | |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 223 | static int check_acl(struct inode *inode, int mask) |
| 224 | { |
Linus Torvalds | 84635d6 | 2011-07-25 22:47:03 -0700 | [diff] [blame] | 225 | #ifdef CONFIG_FS_POSIX_ACL |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 226 | struct posix_acl *acl; |
| 227 | |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 228 | if (mask & MAY_NOT_BLOCK) { |
Al Viro | 3567866 | 2011-08-02 21:32:13 -0400 | [diff] [blame] | 229 | acl = get_cached_acl_rcu(inode, ACL_TYPE_ACCESS); |
| 230 | if (!acl) |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 231 | return -EAGAIN; |
Al Viro | 3567866 | 2011-08-02 21:32:13 -0400 | [diff] [blame] | 232 | /* no ->get_acl() calls in RCU mode... */ |
| 233 | if (acl == ACL_NOT_CACHED) |
| 234 | return -ECHILD; |
Ari Savolainen | 206b1d0 | 2011-08-06 19:43:07 +0300 | [diff] [blame] | 235 | return posix_acl_permission(inode, acl, mask & ~MAY_NOT_BLOCK); |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 236 | } |
| 237 | |
| 238 | acl = get_cached_acl(inode, ACL_TYPE_ACCESS); |
| 239 | |
| 240 | /* |
Christoph Hellwig | 4e34e71 | 2011-07-23 17:37:31 +0200 | [diff] [blame] | 241 | * A filesystem can force a ACL callback by just never filling the |
| 242 | * ACL cache. But normally you'd fill the cache either at inode |
| 243 | * instantiation time, or on the first ->get_acl call. |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 244 | * |
Christoph Hellwig | 4e34e71 | 2011-07-23 17:37:31 +0200 | [diff] [blame] | 245 | * If the filesystem doesn't have a get_acl() function at all, we'll |
| 246 | * just create the negative cache entry. |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 247 | */ |
| 248 | if (acl == ACL_NOT_CACHED) { |
Christoph Hellwig | 4e34e71 | 2011-07-23 17:37:31 +0200 | [diff] [blame] | 249 | if (inode->i_op->get_acl) { |
| 250 | acl = inode->i_op->get_acl(inode, ACL_TYPE_ACCESS); |
| 251 | if (IS_ERR(acl)) |
| 252 | return PTR_ERR(acl); |
| 253 | } else { |
| 254 | set_cached_acl(inode, ACL_TYPE_ACCESS, NULL); |
| 255 | return -EAGAIN; |
| 256 | } |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 257 | } |
| 258 | |
| 259 | if (acl) { |
| 260 | int error = posix_acl_permission(inode, acl, mask); |
| 261 | posix_acl_release(acl); |
| 262 | return error; |
| 263 | } |
Linus Torvalds | 84635d6 | 2011-07-25 22:47:03 -0700 | [diff] [blame] | 264 | #endif |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 265 | |
| 266 | return -EAGAIN; |
| 267 | } |
| 268 | |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 269 | /* |
Andreas Gruenbacher | 948409c | 2011-10-23 23:13:33 +0530 | [diff] [blame] | 270 | * This does the basic permission checking |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 271 | */ |
Al Viro | 7e40145 | 2011-06-20 19:12:17 -0400 | [diff] [blame] | 272 | static int acl_permission_check(struct inode *inode, int mask) |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 273 | { |
Linus Torvalds | 26cf46b | 2011-05-13 11:51:01 -0700 | [diff] [blame] | 274 | unsigned int mode = inode->i_mode; |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 275 | |
Eric W. Biederman | 8e96e3b | 2012-03-03 21:17:15 -0800 | [diff] [blame] | 276 | if (likely(uid_eq(current_fsuid(), inode->i_uid))) |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 277 | mode >>= 6; |
| 278 | else { |
Linus Torvalds | e77819e | 2011-07-22 19:30:19 -0700 | [diff] [blame] | 279 | if (IS_POSIXACL(inode) && (mode & S_IRWXG)) { |
Al Viro | 7e40145 | 2011-06-20 19:12:17 -0400 | [diff] [blame] | 280 | int error = check_acl(inode, mask); |
Nick Piggin | b74c79e | 2011-01-07 17:49:58 +1100 | [diff] [blame] | 281 | if (error != -EAGAIN) |
| 282 | return error; |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 283 | } |
| 284 | |
| 285 | if (in_group_p(inode->i_gid)) |
| 286 | mode >>= 3; |
| 287 | } |
| 288 | |
| 289 | /* |
| 290 | * If the DACs are ok we don't need any capability check. |
| 291 | */ |
Al Viro | 9c2c703 | 2011-06-20 19:06:22 -0400 | [diff] [blame] | 292 | if ((mask & ~mode & (MAY_READ | MAY_WRITE | MAY_EXEC)) == 0) |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 293 | return 0; |
| 294 | return -EACCES; |
| 295 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 296 | |
| 297 | /** |
Nick Piggin | b74c79e | 2011-01-07 17:49:58 +1100 | [diff] [blame] | 298 | * generic_permission - check for access rights on a Posix-like filesystem |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 299 | * @inode: inode to check access rights for |
Andreas Gruenbacher | 8fd90c8 | 2011-10-23 23:13:30 +0530 | [diff] [blame] | 300 | * @mask: right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC, ...) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 301 | * |
| 302 | * Used to check for read/write/execute permissions on a file. |
| 303 | * We use "fsuid" for this, letting us set arbitrary permissions |
| 304 | * for filesystem access without changing the "normal" uids which |
Nick Piggin | b74c79e | 2011-01-07 17:49:58 +1100 | [diff] [blame] | 305 | * are used for other things. |
| 306 | * |
| 307 | * generic_permission is rcu-walk aware. It returns -ECHILD in case an rcu-walk |
| 308 | * request cannot be satisfied (eg. requires blocking or too much complexity). |
| 309 | * It would then be called again in ref-walk mode. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 310 | */ |
Al Viro | 2830ba7 | 2011-06-20 19:16:29 -0400 | [diff] [blame] | 311 | int generic_permission(struct inode *inode, int mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 312 | { |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 313 | int ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 314 | |
| 315 | /* |
Andreas Gruenbacher | 948409c | 2011-10-23 23:13:33 +0530 | [diff] [blame] | 316 | * Do the basic permission checks. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 317 | */ |
Al Viro | 7e40145 | 2011-06-20 19:12:17 -0400 | [diff] [blame] | 318 | ret = acl_permission_check(inode, mask); |
Linus Torvalds | 5909ccaa | 2009-08-28 11:51:25 -0700 | [diff] [blame] | 319 | if (ret != -EACCES) |
| 320 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 321 | |
Al Viro | d594e7e | 2011-06-20 19:55:42 -0400 | [diff] [blame] | 322 | if (S_ISDIR(inode->i_mode)) { |
| 323 | /* DACs are overridable for directories */ |
Eric W. Biederman | 1a48e2a | 2011-11-14 16:24:06 -0800 | [diff] [blame] | 324 | if (inode_capable(inode, CAP_DAC_OVERRIDE)) |
Al Viro | d594e7e | 2011-06-20 19:55:42 -0400 | [diff] [blame] | 325 | return 0; |
| 326 | if (!(mask & MAY_WRITE)) |
Eric W. Biederman | 1a48e2a | 2011-11-14 16:24:06 -0800 | [diff] [blame] | 327 | if (inode_capable(inode, CAP_DAC_READ_SEARCH)) |
Al Viro | d594e7e | 2011-06-20 19:55:42 -0400 | [diff] [blame] | 328 | return 0; |
| 329 | return -EACCES; |
| 330 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 331 | /* |
| 332 | * Read/write DACs are always overridable. |
Al Viro | d594e7e | 2011-06-20 19:55:42 -0400 | [diff] [blame] | 333 | * Executable DACs are overridable when there is |
| 334 | * at least one exec bit set. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 335 | */ |
Al Viro | d594e7e | 2011-06-20 19:55:42 -0400 | [diff] [blame] | 336 | if (!(mask & MAY_EXEC) || (inode->i_mode & S_IXUGO)) |
Eric W. Biederman | 1a48e2a | 2011-11-14 16:24:06 -0800 | [diff] [blame] | 337 | if (inode_capable(inode, CAP_DAC_OVERRIDE)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 338 | return 0; |
| 339 | |
| 340 | /* |
| 341 | * Searching includes executable on directories, else just read. |
| 342 | */ |
Serge E. Hallyn | 7ea6600 | 2009-12-29 14:50:19 -0600 | [diff] [blame] | 343 | mask &= MAY_READ | MAY_WRITE | MAY_EXEC; |
Al Viro | d594e7e | 2011-06-20 19:55:42 -0400 | [diff] [blame] | 344 | if (mask == MAY_READ) |
Eric W. Biederman | 1a48e2a | 2011-11-14 16:24:06 -0800 | [diff] [blame] | 345 | if (inode_capable(inode, CAP_DAC_READ_SEARCH)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 346 | return 0; |
| 347 | |
| 348 | return -EACCES; |
| 349 | } |
| 350 | |
Linus Torvalds | 3ddcd05 | 2011-08-06 22:45:50 -0700 | [diff] [blame] | 351 | /* |
| 352 | * We _really_ want to just do "generic_permission()" without |
| 353 | * even looking at the inode->i_op values. So we keep a cache |
| 354 | * flag in inode->i_opflags, that says "this has not special |
| 355 | * permission function, use the fast case". |
| 356 | */ |
| 357 | static inline int do_inode_permission(struct inode *inode, int mask) |
| 358 | { |
| 359 | if (unlikely(!(inode->i_opflags & IOP_FASTPERM))) { |
| 360 | if (likely(inode->i_op->permission)) |
| 361 | return inode->i_op->permission(inode, mask); |
| 362 | |
| 363 | /* This gets set once for the inode lifetime */ |
| 364 | spin_lock(&inode->i_lock); |
| 365 | inode->i_opflags |= IOP_FASTPERM; |
| 366 | spin_unlock(&inode->i_lock); |
| 367 | } |
| 368 | return generic_permission(inode, mask); |
| 369 | } |
| 370 | |
Christoph Hellwig | cb23beb | 2008-10-24 09:59:29 +0200 | [diff] [blame] | 371 | /** |
David Howells | 0bdaea9 | 2012-06-25 12:55:46 +0100 | [diff] [blame] | 372 | * __inode_permission - Check for access rights to a given inode |
| 373 | * @inode: Inode to check permission on |
| 374 | * @mask: Right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) |
Christoph Hellwig | cb23beb | 2008-10-24 09:59:29 +0200 | [diff] [blame] | 375 | * |
David Howells | 0bdaea9 | 2012-06-25 12:55:46 +0100 | [diff] [blame] | 376 | * Check for read/write/execute permissions on an inode. |
Andreas Gruenbacher | 948409c | 2011-10-23 23:13:33 +0530 | [diff] [blame] | 377 | * |
| 378 | * 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] | 379 | * |
| 380 | * This does not check for a read-only file system. You probably want |
| 381 | * inode_permission(). |
Christoph Hellwig | cb23beb | 2008-10-24 09:59:29 +0200 | [diff] [blame] | 382 | */ |
David Howells | 0bdaea9 | 2012-06-25 12:55:46 +0100 | [diff] [blame] | 383 | int __inode_permission(struct inode *inode, int mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 384 | { |
Al Viro | e6305c4 | 2008-07-15 21:03:57 -0400 | [diff] [blame] | 385 | int retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 386 | |
Linus Torvalds | 3ddcd05 | 2011-08-06 22:45:50 -0700 | [diff] [blame] | 387 | if (unlikely(mask & MAY_WRITE)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 388 | /* |
| 389 | * Nobody gets write access to an immutable file. |
| 390 | */ |
| 391 | if (IS_IMMUTABLE(inode)) |
| 392 | return -EACCES; |
| 393 | } |
| 394 | |
Linus Torvalds | 3ddcd05 | 2011-08-06 22:45:50 -0700 | [diff] [blame] | 395 | retval = do_inode_permission(inode, mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 396 | if (retval) |
| 397 | return retval; |
| 398 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 399 | retval = devcgroup_inode_permission(inode, mask); |
| 400 | if (retval) |
| 401 | return retval; |
| 402 | |
Eric Paris | d09ca73 | 2010-07-23 11:43:57 -0400 | [diff] [blame] | 403 | return security_inode_permission(inode, mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 404 | } |
| 405 | |
Al Viro | f4d6ff8 | 2011-06-19 13:14:21 -0400 | [diff] [blame] | 406 | /** |
David Howells | 0bdaea9 | 2012-06-25 12:55:46 +0100 | [diff] [blame] | 407 | * sb_permission - Check superblock-level permissions |
| 408 | * @sb: Superblock of inode to check permission on |
Randy Dunlap | 5585263 | 2012-08-18 17:39:25 -0700 | [diff] [blame] | 409 | * @inode: Inode to check permission on |
David Howells | 0bdaea9 | 2012-06-25 12:55:46 +0100 | [diff] [blame] | 410 | * @mask: Right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) |
| 411 | * |
| 412 | * Separate out file-system wide checks from inode-specific permission checks. |
| 413 | */ |
| 414 | static int sb_permission(struct super_block *sb, struct inode *inode, int mask) |
| 415 | { |
| 416 | if (unlikely(mask & MAY_WRITE)) { |
| 417 | umode_t mode = inode->i_mode; |
| 418 | |
| 419 | /* Nobody gets write access to a read-only fs. */ |
| 420 | if ((sb->s_flags & MS_RDONLY) && |
| 421 | (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode))) |
| 422 | return -EROFS; |
| 423 | } |
| 424 | return 0; |
| 425 | } |
| 426 | |
| 427 | /** |
| 428 | * inode_permission - Check for access rights to a given inode |
| 429 | * @inode: Inode to check permission on |
| 430 | * @mask: Right to check for (%MAY_READ, %MAY_WRITE, %MAY_EXEC) |
| 431 | * |
| 432 | * Check for read/write/execute permissions on an inode. We use fs[ug]id for |
| 433 | * this, letting us set arbitrary permissions for filesystem access without |
| 434 | * changing the "normal" UIDs which are used for other things. |
| 435 | * |
| 436 | * When checking for MAY_APPEND, MAY_WRITE must also be set in @mask. |
| 437 | */ |
| 438 | int inode_permission(struct inode *inode, int mask) |
| 439 | { |
| 440 | int retval; |
| 441 | |
| 442 | retval = sb_permission(inode->i_sb, inode, mask); |
| 443 | if (retval) |
| 444 | return retval; |
| 445 | return __inode_permission(inode, mask); |
| 446 | } |
| 447 | |
| 448 | /** |
Jan Blunck | 5dd784d0 | 2008-02-14 19:34:38 -0800 | [diff] [blame] | 449 | * path_get - get a reference to a path |
| 450 | * @path: path to get the reference to |
| 451 | * |
| 452 | * Given a path increment the reference count to the dentry and the vfsmount. |
| 453 | */ |
Al Viro | dcf787f | 2013-03-01 23:51:07 -0500 | [diff] [blame] | 454 | void path_get(const struct path *path) |
Jan Blunck | 5dd784d0 | 2008-02-14 19:34:38 -0800 | [diff] [blame] | 455 | { |
| 456 | mntget(path->mnt); |
| 457 | dget(path->dentry); |
| 458 | } |
| 459 | EXPORT_SYMBOL(path_get); |
| 460 | |
| 461 | /** |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 462 | * path_put - put a reference to a path |
| 463 | * @path: path to put the reference to |
| 464 | * |
| 465 | * Given a path decrement the reference count to the dentry and the vfsmount. |
| 466 | */ |
Al Viro | dcf787f | 2013-03-01 23:51:07 -0500 | [diff] [blame] | 467 | void path_put(const struct path *path) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 468 | { |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 469 | dput(path->dentry); |
| 470 | mntput(path->mnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 471 | } |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 472 | EXPORT_SYMBOL(path_put); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 473 | |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 474 | /* |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 475 | * Path walking has 2 modes, rcu-walk and ref-walk (see |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 476 | * Documentation/filesystems/path-lookup.txt). In situations when we can't |
| 477 | * continue in RCU mode, we attempt to drop out of rcu-walk mode and grab |
| 478 | * normal reference counts on dentries and vfsmounts to transition to rcu-walk |
| 479 | * mode. Refcounts are grabbed at the last known good point before rcu-walk |
| 480 | * got stuck, so ref-walk may continue from there. If this is not successful |
| 481 | * (eg. a seqcount has changed), then failure is returned and it's up to caller |
| 482 | * to restart the path walk from the beginning in ref-walk mode. |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 483 | */ |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 484 | |
Al Viro | 32a7991 | 2012-07-18 20:43:19 +0400 | [diff] [blame] | 485 | static inline void lock_rcu_walk(void) |
| 486 | { |
| 487 | br_read_lock(&vfsmount_lock); |
| 488 | rcu_read_lock(); |
| 489 | } |
| 490 | |
| 491 | static inline void unlock_rcu_walk(void) |
| 492 | { |
| 493 | rcu_read_unlock(); |
| 494 | br_read_unlock(&vfsmount_lock); |
| 495 | } |
| 496 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 497 | /** |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 498 | * unlazy_walk - try to switch to ref-walk mode. |
| 499 | * @nd: nameidata pathwalk data |
| 500 | * @dentry: child of nd->path.dentry or NULL |
Randy Dunlap | 3919162 | 2011-01-08 19:36:21 -0800 | [diff] [blame] | 501 | * Returns: 0 on success, -ECHILD on failure |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 502 | * |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 503 | * unlazy_walk attempts to legitimize the current nd->path, nd->root and dentry |
| 504 | * for ref-walk mode. @dentry must be a path found by a do_lookup call on |
| 505 | * @nd or NULL. Must be called from rcu-walk context. |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 506 | */ |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 507 | static int unlazy_walk(struct nameidata *nd, struct dentry *dentry) |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 508 | { |
| 509 | struct fs_struct *fs = current->fs; |
| 510 | struct dentry *parent = nd->path.dentry; |
Al Viro | 5b6ca02 | 2011-03-09 23:04:47 -0500 | [diff] [blame] | 511 | int want_root = 0; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 512 | |
| 513 | BUG_ON(!(nd->flags & LOOKUP_RCU)); |
Al Viro | 5b6ca02 | 2011-03-09 23:04:47 -0500 | [diff] [blame] | 514 | if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT)) { |
| 515 | want_root = 1; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 516 | spin_lock(&fs->lock); |
| 517 | if (nd->root.mnt != fs->root.mnt || |
| 518 | nd->root.dentry != fs->root.dentry) |
| 519 | goto err_root; |
| 520 | } |
| 521 | spin_lock(&parent->d_lock); |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 522 | if (!dentry) { |
| 523 | if (!__d_rcu_to_refcount(parent, nd->seq)) |
| 524 | goto err_parent; |
| 525 | BUG_ON(nd->inode != parent->d_inode); |
| 526 | } else { |
Al Viro | 94c0d4e | 2011-07-12 21:40:23 -0400 | [diff] [blame] | 527 | if (dentry->d_parent != parent) |
| 528 | goto err_parent; |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 529 | spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); |
| 530 | if (!__d_rcu_to_refcount(dentry, nd->seq)) |
| 531 | goto err_child; |
| 532 | /* |
| 533 | * If the sequence check on the child dentry passed, then |
| 534 | * the child has not been removed from its parent. This |
| 535 | * means the parent dentry must be valid and able to take |
| 536 | * a reference at this point. |
| 537 | */ |
| 538 | BUG_ON(!IS_ROOT(dentry) && dentry->d_parent != parent); |
| 539 | BUG_ON(!parent->d_count); |
| 540 | parent->d_count++; |
| 541 | spin_unlock(&dentry->d_lock); |
| 542 | } |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 543 | spin_unlock(&parent->d_lock); |
Al Viro | 5b6ca02 | 2011-03-09 23:04:47 -0500 | [diff] [blame] | 544 | if (want_root) { |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 545 | path_get(&nd->root); |
| 546 | spin_unlock(&fs->lock); |
| 547 | } |
| 548 | mntget(nd->path.mnt); |
| 549 | |
Al Viro | 32a7991 | 2012-07-18 20:43:19 +0400 | [diff] [blame] | 550 | unlock_rcu_walk(); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 551 | nd->flags &= ~LOOKUP_RCU; |
| 552 | return 0; |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 553 | |
| 554 | err_child: |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 555 | spin_unlock(&dentry->d_lock); |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 556 | err_parent: |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 557 | spin_unlock(&parent->d_lock); |
| 558 | err_root: |
Al Viro | 5b6ca02 | 2011-03-09 23:04:47 -0500 | [diff] [blame] | 559 | if (want_root) |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 560 | spin_unlock(&fs->lock); |
| 561 | return -ECHILD; |
| 562 | } |
| 563 | |
Al Viro | 4ce16ef3 | 2012-06-10 16:10:59 -0400 | [diff] [blame] | 564 | static inline int d_revalidate(struct dentry *dentry, unsigned int flags) |
Nick Piggin | 34286d6 | 2011-01-07 17:49:57 +1100 | [diff] [blame] | 565 | { |
Al Viro | 4ce16ef3 | 2012-06-10 16:10:59 -0400 | [diff] [blame] | 566 | return dentry->d_op->d_revalidate(dentry, flags); |
Nick Piggin | 34286d6 | 2011-01-07 17:49:57 +1100 | [diff] [blame] | 567 | } |
| 568 | |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 569 | /** |
| 570 | * complete_walk - successful completion of path walk |
| 571 | * @nd: pointer nameidata |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 572 | * |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 573 | * If we had been in RCU mode, drop out of it and legitimize nd->path. |
| 574 | * Revalidate the final result, unless we'd already done that during |
| 575 | * the path walk or the filesystem doesn't ask for it. Return 0 on |
| 576 | * success, -error on failure. In case of failure caller does not |
| 577 | * need to drop nd->path. |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 578 | */ |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 579 | static int complete_walk(struct nameidata *nd) |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 580 | { |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 581 | struct dentry *dentry = nd->path.dentry; |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 582 | int status; |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 583 | |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 584 | if (nd->flags & LOOKUP_RCU) { |
| 585 | nd->flags &= ~LOOKUP_RCU; |
| 586 | if (!(nd->flags & LOOKUP_ROOT)) |
| 587 | nd->root.mnt = NULL; |
| 588 | spin_lock(&dentry->d_lock); |
| 589 | if (unlikely(!__d_rcu_to_refcount(dentry, nd->seq))) { |
| 590 | spin_unlock(&dentry->d_lock); |
Al Viro | 32a7991 | 2012-07-18 20:43:19 +0400 | [diff] [blame] | 591 | unlock_rcu_walk(); |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 592 | return -ECHILD; |
| 593 | } |
| 594 | BUG_ON(nd->inode != dentry->d_inode); |
| 595 | spin_unlock(&dentry->d_lock); |
| 596 | mntget(nd->path.mnt); |
Al Viro | 32a7991 | 2012-07-18 20:43:19 +0400 | [diff] [blame] | 597 | unlock_rcu_walk(); |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 598 | } |
| 599 | |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 600 | if (likely(!(nd->flags & LOOKUP_JUMPED))) |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 601 | return 0; |
| 602 | |
Jeff Layton | ecf3d1f | 2013-02-20 11:19:05 -0500 | [diff] [blame] | 603 | if (likely(!(dentry->d_flags & DCACHE_OP_WEAK_REVALIDATE))) |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 604 | return 0; |
| 605 | |
Jeff Layton | ecf3d1f | 2013-02-20 11:19:05 -0500 | [diff] [blame] | 606 | status = dentry->d_op->d_weak_revalidate(dentry, nd->flags); |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 607 | if (status > 0) |
| 608 | return 0; |
| 609 | |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 610 | if (!status) |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 611 | status = -ESTALE; |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 612 | |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 613 | path_put(&nd->path); |
Jeff Layton | 39159de | 2009-12-07 12:01:50 -0500 | [diff] [blame] | 614 | return status; |
| 615 | } |
| 616 | |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 617 | static __always_inline void set_root(struct nameidata *nd) |
| 618 | { |
Miklos Szeredi | f7ad3c6 | 2010-08-10 11:41:36 +0200 | [diff] [blame] | 619 | if (!nd->root.mnt) |
| 620 | get_fs_root(current->fs, &nd->root); |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 621 | } |
| 622 | |
Al Viro | 6de88d7 | 2009-08-09 01:41:57 +0400 | [diff] [blame] | 623 | static int link_path_walk(const char *, struct nameidata *); |
| 624 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 625 | static __always_inline void set_root_rcu(struct nameidata *nd) |
| 626 | { |
| 627 | if (!nd->root.mnt) { |
| 628 | struct fs_struct *fs = current->fs; |
Nick Piggin | c28cc36 | 2011-01-07 17:49:53 +1100 | [diff] [blame] | 629 | unsigned seq; |
| 630 | |
| 631 | do { |
| 632 | seq = read_seqcount_begin(&fs->seq); |
| 633 | nd->root = fs->root; |
Tim Chen | c153001 | 2011-04-15 11:39:29 -0700 | [diff] [blame] | 634 | nd->seq = __read_seqcount_begin(&nd->root.dentry->d_seq); |
Nick Piggin | c28cc36 | 2011-01-07 17:49:53 +1100 | [diff] [blame] | 635 | } while (read_seqcount_retry(&fs->seq, seq)); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 636 | } |
| 637 | } |
| 638 | |
Arjan van de Ven | f166235 | 2006-01-14 13:21:31 -0800 | [diff] [blame] | 639 | static __always_inline int __vfs_follow_link(struct nameidata *nd, const char *link) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 640 | { |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 641 | int ret; |
| 642 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 643 | if (IS_ERR(link)) |
| 644 | goto fail; |
| 645 | |
| 646 | if (*link == '/') { |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 647 | set_root(nd); |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 648 | path_put(&nd->path); |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 649 | nd->path = nd->root; |
| 650 | path_get(&nd->root); |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 651 | nd->flags |= LOOKUP_JUMPED; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 652 | } |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 653 | nd->inode = nd->path.dentry->d_inode; |
Christoph Hellwig | b4091d5 | 2008-11-05 15:07:21 +0100 | [diff] [blame] | 654 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 655 | ret = link_path_walk(link, nd); |
| 656 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 657 | fail: |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 658 | path_put(&nd->path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 659 | return PTR_ERR(link); |
| 660 | } |
| 661 | |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 662 | static void path_put_conditional(struct path *path, struct nameidata *nd) |
Miklos Szeredi | 09dd17d | 2005-09-06 15:18:21 -0700 | [diff] [blame] | 663 | { |
| 664 | dput(path->dentry); |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 665 | if (path->mnt != nd->path.mnt) |
Miklos Szeredi | 09dd17d | 2005-09-06 15:18:21 -0700 | [diff] [blame] | 666 | mntput(path->mnt); |
| 667 | } |
| 668 | |
Nick Piggin | 7b9337a | 2011-01-14 08:42:43 +0000 | [diff] [blame] | 669 | static inline void path_to_nameidata(const struct path *path, |
| 670 | struct nameidata *nd) |
Miklos Szeredi | 09dd17d | 2005-09-06 15:18:21 -0700 | [diff] [blame] | 671 | { |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 672 | if (!(nd->flags & LOOKUP_RCU)) { |
| 673 | dput(nd->path.dentry); |
| 674 | if (nd->path.mnt != path->mnt) |
| 675 | mntput(nd->path.mnt); |
Huang Shijie | 9a22968 | 2010-04-02 17:37:13 +0800 | [diff] [blame] | 676 | } |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 677 | nd->path.mnt = path->mnt; |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 678 | nd->path.dentry = path->dentry; |
Miklos Szeredi | 09dd17d | 2005-09-06 15:18:21 -0700 | [diff] [blame] | 679 | } |
| 680 | |
Christoph Hellwig | b5fb63c1 | 2012-06-18 10:47:04 -0400 | [diff] [blame] | 681 | /* |
| 682 | * Helper to directly jump to a known parsed path from ->follow_link, |
| 683 | * caller must have taken a reference to path beforehand. |
| 684 | */ |
| 685 | void nd_jump_link(struct nameidata *nd, struct path *path) |
| 686 | { |
| 687 | path_put(&nd->path); |
| 688 | |
| 689 | nd->path = *path; |
| 690 | nd->inode = nd->path.dentry->d_inode; |
| 691 | nd->flags |= LOOKUP_JUMPED; |
Christoph Hellwig | b5fb63c1 | 2012-06-18 10:47:04 -0400 | [diff] [blame] | 692 | } |
| 693 | |
Al Viro | 574197e | 2011-03-14 22:20:34 -0400 | [diff] [blame] | 694 | static inline void put_link(struct nameidata *nd, struct path *link, void *cookie) |
| 695 | { |
| 696 | struct inode *inode = link->dentry->d_inode; |
Al Viro | 6d7b5aa | 2012-06-10 04:15:17 -0400 | [diff] [blame] | 697 | if (inode->i_op->put_link) |
Al Viro | 574197e | 2011-03-14 22:20:34 -0400 | [diff] [blame] | 698 | inode->i_op->put_link(link->dentry, nd, cookie); |
| 699 | path_put(link); |
| 700 | } |
| 701 | |
Linus Torvalds | 561ec64 | 2012-10-26 10:05:07 -0700 | [diff] [blame] | 702 | int sysctl_protected_symlinks __read_mostly = 0; |
| 703 | int sysctl_protected_hardlinks __read_mostly = 0; |
Kees Cook | 800179c | 2012-07-25 17:29:07 -0700 | [diff] [blame] | 704 | |
| 705 | /** |
| 706 | * may_follow_link - Check symlink following for unsafe situations |
| 707 | * @link: The path of the symlink |
Randy Dunlap | 5585263 | 2012-08-18 17:39:25 -0700 | [diff] [blame] | 708 | * @nd: nameidata pathwalk data |
Kees Cook | 800179c | 2012-07-25 17:29:07 -0700 | [diff] [blame] | 709 | * |
| 710 | * In the case of the sysctl_protected_symlinks sysctl being enabled, |
| 711 | * CAP_DAC_OVERRIDE needs to be specifically ignored if the symlink is |
| 712 | * in a sticky world-writable directory. This is to protect privileged |
| 713 | * processes from failing races against path names that may change out |
| 714 | * from under them by way of other users creating malicious symlinks. |
| 715 | * It will permit symlinks to be followed only when outside a sticky |
| 716 | * world-writable directory, or when the uid of the symlink and follower |
| 717 | * match, or when the directory owner matches the symlink's owner. |
| 718 | * |
| 719 | * Returns 0 if following the symlink is allowed, -ve on error. |
| 720 | */ |
| 721 | static inline int may_follow_link(struct path *link, struct nameidata *nd) |
| 722 | { |
| 723 | const struct inode *inode; |
| 724 | const struct inode *parent; |
| 725 | |
| 726 | if (!sysctl_protected_symlinks) |
| 727 | return 0; |
| 728 | |
| 729 | /* Allowed if owner and follower match. */ |
| 730 | inode = link->dentry->d_inode; |
Eric W. Biederman | 81abe27 | 2012-08-03 09:38:08 -0700 | [diff] [blame] | 731 | if (uid_eq(current_cred()->fsuid, inode->i_uid)) |
Kees Cook | 800179c | 2012-07-25 17:29:07 -0700 | [diff] [blame] | 732 | return 0; |
| 733 | |
| 734 | /* Allowed if parent directory not sticky and world-writable. */ |
| 735 | parent = nd->path.dentry->d_inode; |
| 736 | if ((parent->i_mode & (S_ISVTX|S_IWOTH)) != (S_ISVTX|S_IWOTH)) |
| 737 | return 0; |
| 738 | |
| 739 | /* Allowed if parent directory and link owner match. */ |
Eric W. Biederman | 81abe27 | 2012-08-03 09:38:08 -0700 | [diff] [blame] | 740 | if (uid_eq(parent->i_uid, inode->i_uid)) |
Kees Cook | 800179c | 2012-07-25 17:29:07 -0700 | [diff] [blame] | 741 | return 0; |
| 742 | |
Sasha Levin | ffd8d10 | 2012-10-04 19:56:40 -0400 | [diff] [blame] | 743 | audit_log_link_denied("follow_link", link); |
Kees Cook | 800179c | 2012-07-25 17:29:07 -0700 | [diff] [blame] | 744 | path_put_conditional(link, nd); |
| 745 | path_put(&nd->path); |
| 746 | return -EACCES; |
| 747 | } |
| 748 | |
| 749 | /** |
| 750 | * safe_hardlink_source - Check for safe hardlink conditions |
| 751 | * @inode: the source inode to hardlink from |
| 752 | * |
| 753 | * Return false if at least one of the following conditions: |
| 754 | * - inode is not a regular file |
| 755 | * - inode is setuid |
| 756 | * - inode is setgid and group-exec |
| 757 | * - access failure for read and write |
| 758 | * |
| 759 | * Otherwise returns true. |
| 760 | */ |
| 761 | static bool safe_hardlink_source(struct inode *inode) |
| 762 | { |
| 763 | umode_t mode = inode->i_mode; |
| 764 | |
| 765 | /* Special files should not get pinned to the filesystem. */ |
| 766 | if (!S_ISREG(mode)) |
| 767 | return false; |
| 768 | |
| 769 | /* Setuid files should not get pinned to the filesystem. */ |
| 770 | if (mode & S_ISUID) |
| 771 | return false; |
| 772 | |
| 773 | /* Executable setgid files should not get pinned to the filesystem. */ |
| 774 | if ((mode & (S_ISGID | S_IXGRP)) == (S_ISGID | S_IXGRP)) |
| 775 | return false; |
| 776 | |
| 777 | /* Hardlinking to unreadable or unwritable sources is dangerous. */ |
| 778 | if (inode_permission(inode, MAY_READ | MAY_WRITE)) |
| 779 | return false; |
| 780 | |
| 781 | return true; |
| 782 | } |
| 783 | |
| 784 | /** |
| 785 | * may_linkat - Check permissions for creating a hardlink |
| 786 | * @link: the source to hardlink from |
| 787 | * |
| 788 | * Block hardlink when all of: |
| 789 | * - sysctl_protected_hardlinks enabled |
| 790 | * - fsuid does not match inode |
| 791 | * - hardlink source is unsafe (see safe_hardlink_source() above) |
| 792 | * - not CAP_FOWNER |
| 793 | * |
| 794 | * Returns 0 if successful, -ve on error. |
| 795 | */ |
| 796 | static int may_linkat(struct path *link) |
| 797 | { |
| 798 | const struct cred *cred; |
| 799 | struct inode *inode; |
| 800 | |
| 801 | if (!sysctl_protected_hardlinks) |
| 802 | return 0; |
| 803 | |
| 804 | cred = current_cred(); |
| 805 | inode = link->dentry->d_inode; |
| 806 | |
| 807 | /* Source inode owner (or CAP_FOWNER) can hardlink all they like, |
| 808 | * otherwise, it must be a safe source. |
| 809 | */ |
Eric W. Biederman | 81abe27 | 2012-08-03 09:38:08 -0700 | [diff] [blame] | 810 | if (uid_eq(cred->fsuid, inode->i_uid) || safe_hardlink_source(inode) || |
Kees Cook | 800179c | 2012-07-25 17:29:07 -0700 | [diff] [blame] | 811 | capable(CAP_FOWNER)) |
| 812 | return 0; |
| 813 | |
Kees Cook | a51d9ea | 2012-07-25 17:29:08 -0700 | [diff] [blame] | 814 | audit_log_link_denied("linkat", link); |
Kees Cook | 800179c | 2012-07-25 17:29:07 -0700 | [diff] [blame] | 815 | return -EPERM; |
| 816 | } |
| 817 | |
Al Viro | def4af3 | 2009-12-26 08:37:05 -0500 | [diff] [blame] | 818 | static __always_inline int |
Al Viro | 574197e | 2011-03-14 22:20:34 -0400 | [diff] [blame] | 819 | follow_link(struct path *link, struct nameidata *nd, void **p) |
Ian Kent | 051d381 | 2006-03-27 01:14:53 -0800 | [diff] [blame] | 820 | { |
Nick Piggin | 7b9337a | 2011-01-14 08:42:43 +0000 | [diff] [blame] | 821 | struct dentry *dentry = link->dentry; |
Al Viro | 6d7b5aa | 2012-06-10 04:15:17 -0400 | [diff] [blame] | 822 | int error; |
| 823 | char *s; |
Ian Kent | 051d381 | 2006-03-27 01:14:53 -0800 | [diff] [blame] | 824 | |
Al Viro | 844a391 | 2011-02-15 00:38:26 -0500 | [diff] [blame] | 825 | BUG_ON(nd->flags & LOOKUP_RCU); |
| 826 | |
Al Viro | 0e79458 | 2011-03-16 02:45:02 -0400 | [diff] [blame] | 827 | if (link->mnt == nd->path.mnt) |
| 828 | mntget(link->mnt); |
| 829 | |
Al Viro | 6d7b5aa | 2012-06-10 04:15:17 -0400 | [diff] [blame] | 830 | error = -ELOOP; |
| 831 | if (unlikely(current->total_link_count >= 40)) |
| 832 | goto out_put_nd_path; |
| 833 | |
Al Viro | 574197e | 2011-03-14 22:20:34 -0400 | [diff] [blame] | 834 | cond_resched(); |
| 835 | current->total_link_count++; |
| 836 | |
Al Viro | 68ac123 | 2012-03-15 08:21:57 -0400 | [diff] [blame] | 837 | touch_atime(link); |
Ian Kent | 051d381 | 2006-03-27 01:14:53 -0800 | [diff] [blame] | 838 | nd_set_link(nd, NULL); |
| 839 | |
Al Viro | 36f3b4f | 2011-02-22 21:24:38 -0500 | [diff] [blame] | 840 | error = security_inode_follow_link(link->dentry, nd); |
Al Viro | 6d7b5aa | 2012-06-10 04:15:17 -0400 | [diff] [blame] | 841 | if (error) |
| 842 | goto out_put_nd_path; |
Al Viro | 36f3b4f | 2011-02-22 21:24:38 -0500 | [diff] [blame] | 843 | |
Al Viro | 86acdca1 | 2009-12-22 23:45:11 -0500 | [diff] [blame] | 844 | nd->last_type = LAST_BIND; |
Al Viro | def4af3 | 2009-12-26 08:37:05 -0500 | [diff] [blame] | 845 | *p = dentry->d_inode->i_op->follow_link(dentry, nd); |
| 846 | error = PTR_ERR(*p); |
Al Viro | 6d7b5aa | 2012-06-10 04:15:17 -0400 | [diff] [blame] | 847 | if (IS_ERR(*p)) |
Christoph Hellwig | 408ef01 | 2012-06-18 10:47:03 -0400 | [diff] [blame] | 848 | goto out_put_nd_path; |
Al Viro | 6d7b5aa | 2012-06-10 04:15:17 -0400 | [diff] [blame] | 849 | |
| 850 | error = 0; |
| 851 | s = nd_get_link(nd); |
| 852 | if (s) { |
| 853 | error = __vfs_follow_link(nd, s); |
Christoph Hellwig | b5fb63c1 | 2012-06-18 10:47:04 -0400 | [diff] [blame] | 854 | if (unlikely(error)) |
| 855 | put_link(nd, link, *p); |
Ian Kent | 051d381 | 2006-03-27 01:14:53 -0800 | [diff] [blame] | 856 | } |
Al Viro | 6d7b5aa | 2012-06-10 04:15:17 -0400 | [diff] [blame] | 857 | |
| 858 | return error; |
| 859 | |
| 860 | out_put_nd_path: |
Arnd Bergmann | 98f6ef6 | 2012-10-11 13:20:00 +0000 | [diff] [blame] | 861 | *p = NULL; |
Al Viro | 6d7b5aa | 2012-06-10 04:15:17 -0400 | [diff] [blame] | 862 | path_put(&nd->path); |
Al Viro | 6d7b5aa | 2012-06-10 04:15:17 -0400 | [diff] [blame] | 863 | path_put(link); |
Ian Kent | 051d381 | 2006-03-27 01:14:53 -0800 | [diff] [blame] | 864 | return error; |
| 865 | } |
| 866 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 867 | static int follow_up_rcu(struct path *path) |
| 868 | { |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 869 | struct mount *mnt = real_mount(path->mnt); |
| 870 | struct mount *parent; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 871 | struct dentry *mountpoint; |
| 872 | |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 873 | parent = mnt->mnt_parent; |
| 874 | if (&parent->mnt == path->mnt) |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 875 | return 0; |
Al Viro | a73324d | 2011-11-24 22:25:07 -0500 | [diff] [blame] | 876 | mountpoint = mnt->mnt_mountpoint; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 877 | path->dentry = mountpoint; |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 878 | path->mnt = &parent->mnt; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 879 | return 1; |
| 880 | } |
| 881 | |
David Howells | f015f126 | 2012-06-25 12:55:28 +0100 | [diff] [blame] | 882 | /* |
| 883 | * follow_up - Find the mountpoint of path's vfsmount |
| 884 | * |
| 885 | * Given a path, find the mountpoint of its source file system. |
| 886 | * Replace @path with the path of the mountpoint in the parent mount. |
| 887 | * Up is towards /. |
| 888 | * |
| 889 | * Return 1 if we went up a level and 0 if we were already at the |
| 890 | * root. |
| 891 | */ |
Al Viro | bab77eb | 2009-04-18 03:26:48 -0400 | [diff] [blame] | 892 | int follow_up(struct path *path) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 893 | { |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 894 | struct mount *mnt = real_mount(path->mnt); |
| 895 | struct mount *parent; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 896 | struct dentry *mountpoint; |
Nick Piggin | 99b7db7 | 2010-08-18 04:37:39 +1000 | [diff] [blame] | 897 | |
Andi Kleen | 962830d | 2012-05-08 13:32:02 +0930 | [diff] [blame] | 898 | br_read_lock(&vfsmount_lock); |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 899 | parent = mnt->mnt_parent; |
Al Viro | 3c0a616 | 2012-07-18 17:32:50 +0400 | [diff] [blame] | 900 | if (parent == mnt) { |
Andi Kleen | 962830d | 2012-05-08 13:32:02 +0930 | [diff] [blame] | 901 | br_read_unlock(&vfsmount_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 902 | return 0; |
| 903 | } |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 904 | mntget(&parent->mnt); |
Al Viro | a73324d | 2011-11-24 22:25:07 -0500 | [diff] [blame] | 905 | mountpoint = dget(mnt->mnt_mountpoint); |
Andi Kleen | 962830d | 2012-05-08 13:32:02 +0930 | [diff] [blame] | 906 | br_read_unlock(&vfsmount_lock); |
Al Viro | bab77eb | 2009-04-18 03:26:48 -0400 | [diff] [blame] | 907 | dput(path->dentry); |
| 908 | path->dentry = mountpoint; |
| 909 | mntput(path->mnt); |
Al Viro | 0714a53 | 2011-11-24 22:19:58 -0500 | [diff] [blame] | 910 | path->mnt = &parent->mnt; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 911 | return 1; |
| 912 | } |
| 913 | |
Nick Piggin | b5c84bf | 2011-01-07 17:49:38 +1100 | [diff] [blame] | 914 | /* |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 915 | * Perform an automount |
| 916 | * - return -EISDIR to tell follow_managed() to stop and return the path we |
| 917 | * were called with. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 918 | */ |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 919 | static int follow_automount(struct path *path, unsigned flags, |
| 920 | bool *need_mntput) |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 921 | { |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 922 | struct vfsmount *mnt; |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 923 | int err; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 924 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 925 | if (!path->dentry->d_op || !path->dentry->d_op->d_automount) |
| 926 | return -EREMOTE; |
Al Viro | 463ffb2 | 2005-06-06 13:36:05 -0700 | [diff] [blame] | 927 | |
Miklos Szeredi | 0ec26fd | 2011-09-05 18:06:26 +0200 | [diff] [blame] | 928 | /* We don't want to mount if someone's just doing a stat - |
| 929 | * unless they're stat'ing a directory and appended a '/' to |
| 930 | * the name. |
| 931 | * |
| 932 | * We do, however, want to mount if someone wants to open or |
| 933 | * create a file of any type under the mountpoint, wants to |
| 934 | * traverse through the mountpoint or wants to open the |
| 935 | * mounted directory. Also, autofs may mark negative dentries |
| 936 | * as being automount points. These will need the attentions |
| 937 | * of the daemon to instantiate them before they can be used. |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 938 | */ |
Miklos Szeredi | 0ec26fd | 2011-09-05 18:06:26 +0200 | [diff] [blame] | 939 | if (!(flags & (LOOKUP_PARENT | LOOKUP_DIRECTORY | |
Linus Torvalds | d94c177 | 2011-09-26 17:44:55 -0700 | [diff] [blame] | 940 | LOOKUP_OPEN | LOOKUP_CREATE | LOOKUP_AUTOMOUNT)) && |
Miklos Szeredi | 0ec26fd | 2011-09-05 18:06:26 +0200 | [diff] [blame] | 941 | path->dentry->d_inode) |
| 942 | return -EISDIR; |
| 943 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 944 | current->total_link_count++; |
| 945 | if (current->total_link_count >= 40) |
| 946 | return -ELOOP; |
| 947 | |
| 948 | mnt = path->dentry->d_op->d_automount(path); |
| 949 | if (IS_ERR(mnt)) { |
| 950 | /* |
| 951 | * The filesystem is allowed to return -EISDIR here to indicate |
| 952 | * it doesn't want to automount. For instance, autofs would do |
| 953 | * this so that its userspace daemon can mount on this dentry. |
| 954 | * |
| 955 | * However, we can only permit this if it's a terminal point in |
| 956 | * the path being looked up; if it wasn't then the remainder of |
| 957 | * the path is inaccessible and we should say so. |
| 958 | */ |
Al Viro | 49084c3 | 2011-06-25 21:59:52 -0400 | [diff] [blame] | 959 | if (PTR_ERR(mnt) == -EISDIR && (flags & LOOKUP_PARENT)) |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 960 | return -EREMOTE; |
| 961 | return PTR_ERR(mnt); |
| 962 | } |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 963 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 964 | if (!mnt) /* mount collision */ |
| 965 | return 0; |
| 966 | |
Al Viro | 8aef188 | 2011-06-16 15:10:06 +0100 | [diff] [blame] | 967 | if (!*need_mntput) { |
| 968 | /* lock_mount() may release path->mnt on error */ |
| 969 | mntget(path->mnt); |
| 970 | *need_mntput = true; |
| 971 | } |
Al Viro | 19a167a | 2011-01-17 01:35:23 -0500 | [diff] [blame] | 972 | err = finish_automount(mnt, path); |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 973 | |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 974 | switch (err) { |
| 975 | case -EBUSY: |
| 976 | /* Someone else made a mount here whilst we were busy */ |
Al Viro | 19a167a | 2011-01-17 01:35:23 -0500 | [diff] [blame] | 977 | return 0; |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 978 | case 0: |
Al Viro | 8aef188 | 2011-06-16 15:10:06 +0100 | [diff] [blame] | 979 | path_put(path); |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 980 | path->mnt = mnt; |
| 981 | path->dentry = dget(mnt->mnt_root); |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 982 | return 0; |
Al Viro | 19a167a | 2011-01-17 01:35:23 -0500 | [diff] [blame] | 983 | default: |
| 984 | return err; |
David Howells | ea5b778 | 2011-01-14 19:10:03 +0000 | [diff] [blame] | 985 | } |
Al Viro | 19a167a | 2011-01-17 01:35:23 -0500 | [diff] [blame] | 986 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 987 | } |
| 988 | |
| 989 | /* |
| 990 | * Handle a dentry that is managed in some way. |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 991 | * - Flagged for transit management (autofs) |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 992 | * - Flagged as mountpoint |
| 993 | * - Flagged as automount point |
| 994 | * |
| 995 | * This may only be called in refwalk mode. |
| 996 | * |
| 997 | * Serialization is taken care of in namespace.c |
| 998 | */ |
| 999 | static int follow_managed(struct path *path, unsigned flags) |
| 1000 | { |
Al Viro | 8aef188 | 2011-06-16 15:10:06 +0100 | [diff] [blame] | 1001 | struct vfsmount *mnt = path->mnt; /* held by caller, must be left alone */ |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1002 | unsigned managed; |
| 1003 | bool need_mntput = false; |
Al Viro | 8aef188 | 2011-06-16 15:10:06 +0100 | [diff] [blame] | 1004 | int ret = 0; |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1005 | |
| 1006 | /* Given that we're not holding a lock here, we retain the value in a |
| 1007 | * local variable for each dentry as we look at it so that we don't see |
| 1008 | * the components of that value change under us */ |
| 1009 | while (managed = ACCESS_ONCE(path->dentry->d_flags), |
| 1010 | managed &= DCACHE_MANAGED_DENTRY, |
| 1011 | unlikely(managed != 0)) { |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 1012 | /* Allow the filesystem to manage the transit without i_mutex |
| 1013 | * being held. */ |
| 1014 | if (managed & DCACHE_MANAGE_TRANSIT) { |
| 1015 | BUG_ON(!path->dentry->d_op); |
| 1016 | BUG_ON(!path->dentry->d_op->d_manage); |
Al Viro | 1aed3e4 | 2011-03-18 09:09:02 -0400 | [diff] [blame] | 1017 | ret = path->dentry->d_op->d_manage(path->dentry, false); |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 1018 | if (ret < 0) |
Al Viro | 8aef188 | 2011-06-16 15:10:06 +0100 | [diff] [blame] | 1019 | break; |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 1020 | } |
| 1021 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1022 | /* Transit to a mounted filesystem. */ |
| 1023 | if (managed & DCACHE_MOUNTED) { |
| 1024 | struct vfsmount *mounted = lookup_mnt(path); |
| 1025 | if (mounted) { |
| 1026 | dput(path->dentry); |
| 1027 | if (need_mntput) |
| 1028 | mntput(path->mnt); |
| 1029 | path->mnt = mounted; |
| 1030 | path->dentry = dget(mounted->mnt_root); |
| 1031 | need_mntput = true; |
| 1032 | continue; |
| 1033 | } |
| 1034 | |
| 1035 | /* Something is mounted on this dentry in another |
| 1036 | * namespace and/or whatever was mounted there in this |
| 1037 | * namespace got unmounted before we managed to get the |
| 1038 | * vfsmount_lock */ |
| 1039 | } |
| 1040 | |
| 1041 | /* Handle an automount point */ |
| 1042 | if (managed & DCACHE_NEED_AUTOMOUNT) { |
| 1043 | ret = follow_automount(path, flags, &need_mntput); |
| 1044 | if (ret < 0) |
Al Viro | 8aef188 | 2011-06-16 15:10:06 +0100 | [diff] [blame] | 1045 | break; |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1046 | continue; |
| 1047 | } |
| 1048 | |
| 1049 | /* We didn't change the current path point */ |
| 1050 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1051 | } |
Al Viro | 8aef188 | 2011-06-16 15:10:06 +0100 | [diff] [blame] | 1052 | |
| 1053 | if (need_mntput && path->mnt == mnt) |
| 1054 | mntput(path->mnt); |
| 1055 | if (ret == -EISDIR) |
| 1056 | ret = 0; |
Al Viro | a3fbbde | 2011-11-07 21:21:26 +0000 | [diff] [blame] | 1057 | return ret < 0 ? ret : need_mntput; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1058 | } |
| 1059 | |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 1060 | int follow_down_one(struct path *path) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1061 | { |
| 1062 | struct vfsmount *mounted; |
| 1063 | |
Al Viro | 1c755af | 2009-04-18 14:06:57 -0400 | [diff] [blame] | 1064 | mounted = lookup_mnt(path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1065 | if (mounted) { |
Al Viro | 9393bd0 | 2009-04-18 13:58:15 -0400 | [diff] [blame] | 1066 | dput(path->dentry); |
| 1067 | mntput(path->mnt); |
| 1068 | path->mnt = mounted; |
| 1069 | path->dentry = dget(mounted->mnt_root); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1070 | return 1; |
| 1071 | } |
| 1072 | return 0; |
| 1073 | } |
| 1074 | |
Ian Kent | 62a7375 | 2011-03-25 01:51:02 +0800 | [diff] [blame] | 1075 | static inline bool managed_dentry_might_block(struct dentry *dentry) |
| 1076 | { |
| 1077 | return (dentry->d_flags & DCACHE_MANAGE_TRANSIT && |
| 1078 | dentry->d_op->d_manage(dentry, true) < 0); |
| 1079 | } |
| 1080 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1081 | /* |
Al Viro | 287548e | 2011-05-27 06:50:06 -0400 | [diff] [blame] | 1082 | * Try to skip to top of mountpoint pile in rcuwalk mode. Fail if |
| 1083 | * we meet a managed dentry that would need blocking. |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1084 | */ |
| 1085 | static bool __follow_mount_rcu(struct nameidata *nd, struct path *path, |
Al Viro | 287548e | 2011-05-27 06:50:06 -0400 | [diff] [blame] | 1086 | struct inode **inode) |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1087 | { |
Ian Kent | 62a7375 | 2011-03-25 01:51:02 +0800 | [diff] [blame] | 1088 | for (;;) { |
Al Viro | c710536 | 2011-11-24 18:22:03 -0500 | [diff] [blame] | 1089 | struct mount *mounted; |
Ian Kent | 62a7375 | 2011-03-25 01:51:02 +0800 | [diff] [blame] | 1090 | /* |
| 1091 | * Don't forget we might have a non-mountpoint managed dentry |
| 1092 | * that wants to block transit. |
| 1093 | */ |
Al Viro | 287548e | 2011-05-27 06:50:06 -0400 | [diff] [blame] | 1094 | if (unlikely(managed_dentry_might_block(path->dentry))) |
David Howells | ab90911 | 2011-01-14 18:46:51 +0000 | [diff] [blame] | 1095 | return false; |
Ian Kent | 62a7375 | 2011-03-25 01:51:02 +0800 | [diff] [blame] | 1096 | |
| 1097 | if (!d_mountpoint(path->dentry)) |
| 1098 | break; |
| 1099 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1100 | mounted = __lookup_mnt(path->mnt, path->dentry, 1); |
| 1101 | if (!mounted) |
| 1102 | break; |
Al Viro | c710536 | 2011-11-24 18:22:03 -0500 | [diff] [blame] | 1103 | path->mnt = &mounted->mnt; |
| 1104 | path->dentry = mounted->mnt.mnt_root; |
Al Viro | a3fbbde | 2011-11-07 21:21:26 +0000 | [diff] [blame] | 1105 | nd->flags |= LOOKUP_JUMPED; |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1106 | nd->seq = read_seqcount_begin(&path->dentry->d_seq); |
Linus Torvalds | 5943026 | 2011-07-18 15:43:29 -0700 | [diff] [blame] | 1107 | /* |
| 1108 | * Update the inode too. We don't need to re-check the |
| 1109 | * dentry sequence number here after this d_inode read, |
| 1110 | * because a mount-point is always pinned. |
| 1111 | */ |
| 1112 | *inode = path->dentry->d_inode; |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1113 | } |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1114 | return true; |
| 1115 | } |
| 1116 | |
Al Viro | dea3937 | 2011-05-27 06:53:39 -0400 | [diff] [blame] | 1117 | static void follow_mount_rcu(struct nameidata *nd) |
Al Viro | 287548e | 2011-05-27 06:50:06 -0400 | [diff] [blame] | 1118 | { |
Al Viro | dea3937 | 2011-05-27 06:53:39 -0400 | [diff] [blame] | 1119 | while (d_mountpoint(nd->path.dentry)) { |
Al Viro | c710536 | 2011-11-24 18:22:03 -0500 | [diff] [blame] | 1120 | struct mount *mounted; |
Al Viro | dea3937 | 2011-05-27 06:53:39 -0400 | [diff] [blame] | 1121 | mounted = __lookup_mnt(nd->path.mnt, nd->path.dentry, 1); |
Al Viro | 287548e | 2011-05-27 06:50:06 -0400 | [diff] [blame] | 1122 | if (!mounted) |
| 1123 | break; |
Al Viro | c710536 | 2011-11-24 18:22:03 -0500 | [diff] [blame] | 1124 | nd->path.mnt = &mounted->mnt; |
| 1125 | nd->path.dentry = mounted->mnt.mnt_root; |
Al Viro | dea3937 | 2011-05-27 06:53:39 -0400 | [diff] [blame] | 1126 | nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq); |
Al Viro | 287548e | 2011-05-27 06:50:06 -0400 | [diff] [blame] | 1127 | } |
| 1128 | } |
| 1129 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1130 | static int follow_dotdot_rcu(struct nameidata *nd) |
| 1131 | { |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1132 | set_root_rcu(nd); |
| 1133 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1134 | while (1) { |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1135 | if (nd->path.dentry == nd->root.dentry && |
| 1136 | nd->path.mnt == nd->root.mnt) { |
| 1137 | break; |
| 1138 | } |
| 1139 | if (nd->path.dentry != nd->path.mnt->mnt_root) { |
| 1140 | struct dentry *old = nd->path.dentry; |
| 1141 | struct dentry *parent = old->d_parent; |
| 1142 | unsigned seq; |
| 1143 | |
| 1144 | seq = read_seqcount_begin(&parent->d_seq); |
| 1145 | if (read_seqcount_retry(&old->d_seq, nd->seq)) |
Al Viro | ef7562d | 2011-03-04 14:35:59 -0500 | [diff] [blame] | 1146 | goto failed; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1147 | nd->path.dentry = parent; |
| 1148 | nd->seq = seq; |
| 1149 | break; |
| 1150 | } |
| 1151 | if (!follow_up_rcu(&nd->path)) |
| 1152 | break; |
| 1153 | nd->seq = read_seqcount_begin(&nd->path.dentry->d_seq); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1154 | } |
Al Viro | dea3937 | 2011-05-27 06:53:39 -0400 | [diff] [blame] | 1155 | follow_mount_rcu(nd); |
| 1156 | nd->inode = nd->path.dentry->d_inode; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1157 | return 0; |
Al Viro | ef7562d | 2011-03-04 14:35:59 -0500 | [diff] [blame] | 1158 | |
| 1159 | failed: |
| 1160 | nd->flags &= ~LOOKUP_RCU; |
Al Viro | 5b6ca02 | 2011-03-09 23:04:47 -0500 | [diff] [blame] | 1161 | if (!(nd->flags & LOOKUP_ROOT)) |
| 1162 | nd->root.mnt = NULL; |
Al Viro | 32a7991 | 2012-07-18 20:43:19 +0400 | [diff] [blame] | 1163 | unlock_rcu_walk(); |
Al Viro | ef7562d | 2011-03-04 14:35:59 -0500 | [diff] [blame] | 1164 | return -ECHILD; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1165 | } |
| 1166 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1167 | /* |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 1168 | * Follow down to the covering mount currently visible to userspace. At each |
| 1169 | * point, the filesystem owning that dentry may be queried as to whether the |
| 1170 | * caller is permitted to proceed or not. |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 1171 | */ |
Al Viro | 7cc90cc | 2011-03-18 09:04:20 -0400 | [diff] [blame] | 1172 | int follow_down(struct path *path) |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 1173 | { |
| 1174 | unsigned managed; |
| 1175 | int ret; |
| 1176 | |
| 1177 | while (managed = ACCESS_ONCE(path->dentry->d_flags), |
| 1178 | unlikely(managed & DCACHE_MANAGED_DENTRY)) { |
| 1179 | /* Allow the filesystem to manage the transit without i_mutex |
| 1180 | * being held. |
| 1181 | * |
| 1182 | * We indicate to the filesystem if someone is trying to mount |
| 1183 | * something here. This gives autofs the chance to deny anyone |
| 1184 | * other than its daemon the right to mount on its |
| 1185 | * superstructure. |
| 1186 | * |
| 1187 | * The filesystem may sleep at this point. |
| 1188 | */ |
| 1189 | if (managed & DCACHE_MANAGE_TRANSIT) { |
| 1190 | BUG_ON(!path->dentry->d_op); |
| 1191 | BUG_ON(!path->dentry->d_op->d_manage); |
David Howells | ab90911 | 2011-01-14 18:46:51 +0000 | [diff] [blame] | 1192 | ret = path->dentry->d_op->d_manage( |
Al Viro | 1aed3e4 | 2011-03-18 09:09:02 -0400 | [diff] [blame] | 1193 | path->dentry, false); |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 1194 | if (ret < 0) |
| 1195 | return ret == -EISDIR ? 0 : ret; |
| 1196 | } |
| 1197 | |
| 1198 | /* Transit to a mounted filesystem. */ |
| 1199 | if (managed & DCACHE_MOUNTED) { |
| 1200 | struct vfsmount *mounted = lookup_mnt(path); |
| 1201 | if (!mounted) |
| 1202 | break; |
| 1203 | dput(path->dentry); |
| 1204 | mntput(path->mnt); |
| 1205 | path->mnt = mounted; |
| 1206 | path->dentry = dget(mounted->mnt_root); |
| 1207 | continue; |
| 1208 | } |
| 1209 | |
| 1210 | /* Don't handle automount points here */ |
| 1211 | break; |
| 1212 | } |
| 1213 | return 0; |
| 1214 | } |
| 1215 | |
| 1216 | /* |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1217 | * Skip to top of mountpoint pile in refwalk mode for follow_dotdot() |
| 1218 | */ |
| 1219 | static void follow_mount(struct path *path) |
| 1220 | { |
| 1221 | while (d_mountpoint(path->dentry)) { |
| 1222 | struct vfsmount *mounted = lookup_mnt(path); |
| 1223 | if (!mounted) |
| 1224 | break; |
| 1225 | dput(path->dentry); |
| 1226 | mntput(path->mnt); |
| 1227 | path->mnt = mounted; |
| 1228 | path->dentry = dget(mounted->mnt_root); |
| 1229 | } |
| 1230 | } |
| 1231 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1232 | static void follow_dotdot(struct nameidata *nd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1233 | { |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 1234 | set_root(nd); |
Andreas Mohr | e518ddb | 2006-09-29 02:01:22 -0700 | [diff] [blame] | 1235 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1236 | while(1) { |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 1237 | struct dentry *old = nd->path.dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1238 | |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 1239 | if (nd->path.dentry == nd->root.dentry && |
| 1240 | nd->path.mnt == nd->root.mnt) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1241 | break; |
| 1242 | } |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 1243 | if (nd->path.dentry != nd->path.mnt->mnt_root) { |
Al Viro | 3088dd7 | 2010-01-30 15:47:29 -0500 | [diff] [blame] | 1244 | /* rare case of legitimate dget_parent()... */ |
| 1245 | nd->path.dentry = dget_parent(nd->path.dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1246 | dput(old); |
| 1247 | break; |
| 1248 | } |
Al Viro | 3088dd7 | 2010-01-30 15:47:29 -0500 | [diff] [blame] | 1249 | if (!follow_up(&nd->path)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1250 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1251 | } |
Al Viro | 79ed022 | 2009-04-18 13:59:41 -0400 | [diff] [blame] | 1252 | follow_mount(&nd->path); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1253 | nd->inode = nd->path.dentry->d_inode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1254 | } |
| 1255 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1256 | /* |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1257 | * This looks up the name in dcache, possibly revalidates the old dentry and |
| 1258 | * allocates a new one if not found or not valid. In the need_lookup argument |
| 1259 | * returns whether i_op->lookup is necessary. |
| 1260 | * |
| 1261 | * dir->d_inode->i_mutex must be held |
Nick Piggin | baa0389 | 2010-08-18 04:37:31 +1000 | [diff] [blame] | 1262 | */ |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1263 | static struct dentry *lookup_dcache(struct qstr *name, struct dentry *dir, |
Al Viro | 201f956 | 2012-06-22 12:42:10 +0400 | [diff] [blame] | 1264 | unsigned int flags, bool *need_lookup) |
Nick Piggin | baa0389 | 2010-08-18 04:37:31 +1000 | [diff] [blame] | 1265 | { |
Nick Piggin | baa0389 | 2010-08-18 04:37:31 +1000 | [diff] [blame] | 1266 | struct dentry *dentry; |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1267 | int error; |
Nick Piggin | baa0389 | 2010-08-18 04:37:31 +1000 | [diff] [blame] | 1268 | |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1269 | *need_lookup = false; |
| 1270 | dentry = d_lookup(dir, name); |
| 1271 | if (dentry) { |
Jeff Layton | 39e3c95 | 2012-11-28 11:30:53 -0500 | [diff] [blame] | 1272 | if (dentry->d_flags & DCACHE_OP_REVALIDATE) { |
Al Viro | 201f956 | 2012-06-22 12:42:10 +0400 | [diff] [blame] | 1273 | error = d_revalidate(dentry, flags); |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1274 | if (unlikely(error <= 0)) { |
| 1275 | if (error < 0) { |
| 1276 | dput(dentry); |
| 1277 | return ERR_PTR(error); |
| 1278 | } else if (!d_invalidate(dentry)) { |
| 1279 | dput(dentry); |
| 1280 | dentry = NULL; |
| 1281 | } |
| 1282 | } |
| 1283 | } |
| 1284 | } |
Nick Piggin | baa0389 | 2010-08-18 04:37:31 +1000 | [diff] [blame] | 1285 | |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1286 | if (!dentry) { |
| 1287 | dentry = d_alloc(dir, name); |
| 1288 | if (unlikely(!dentry)) |
| 1289 | return ERR_PTR(-ENOMEM); |
Nick Piggin | baa0389 | 2010-08-18 04:37:31 +1000 | [diff] [blame] | 1290 | |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1291 | *need_lookup = true; |
Nick Piggin | baa0389 | 2010-08-18 04:37:31 +1000 | [diff] [blame] | 1292 | } |
| 1293 | return dentry; |
| 1294 | } |
| 1295 | |
| 1296 | /* |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1297 | * Call i_op->lookup on the dentry. The dentry must be negative but may be |
| 1298 | * hashed if it was pouplated with DCACHE_NEED_LOOKUP. |
| 1299 | * |
| 1300 | * dir->d_inode->i_mutex must be held |
Josef Bacik | 44396f4 | 2011-05-31 11:58:49 -0400 | [diff] [blame] | 1301 | */ |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1302 | static struct dentry *lookup_real(struct inode *dir, struct dentry *dentry, |
Al Viro | 72bd866 | 2012-06-10 17:17:17 -0400 | [diff] [blame] | 1303 | unsigned int flags) |
Josef Bacik | 44396f4 | 2011-05-31 11:58:49 -0400 | [diff] [blame] | 1304 | { |
Josef Bacik | 44396f4 | 2011-05-31 11:58:49 -0400 | [diff] [blame] | 1305 | struct dentry *old; |
| 1306 | |
| 1307 | /* Don't create child dentry for a dead directory. */ |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1308 | if (unlikely(IS_DEADDIR(dir))) { |
Miklos Szeredi | e188dc0 | 2012-02-03 14:25:18 +0100 | [diff] [blame] | 1309 | dput(dentry); |
Josef Bacik | 44396f4 | 2011-05-31 11:58:49 -0400 | [diff] [blame] | 1310 | return ERR_PTR(-ENOENT); |
Miklos Szeredi | e188dc0 | 2012-02-03 14:25:18 +0100 | [diff] [blame] | 1311 | } |
Josef Bacik | 44396f4 | 2011-05-31 11:58:49 -0400 | [diff] [blame] | 1312 | |
Al Viro | 72bd866 | 2012-06-10 17:17:17 -0400 | [diff] [blame] | 1313 | old = dir->i_op->lookup(dir, dentry, flags); |
Josef Bacik | 44396f4 | 2011-05-31 11:58:49 -0400 | [diff] [blame] | 1314 | if (unlikely(old)) { |
| 1315 | dput(dentry); |
| 1316 | dentry = old; |
| 1317 | } |
| 1318 | return dentry; |
| 1319 | } |
| 1320 | |
Al Viro | a325554 | 2012-03-30 14:41:51 -0400 | [diff] [blame] | 1321 | static struct dentry *__lookup_hash(struct qstr *name, |
Al Viro | 72bd866 | 2012-06-10 17:17:17 -0400 | [diff] [blame] | 1322 | struct dentry *base, unsigned int flags) |
Al Viro | a325554 | 2012-03-30 14:41:51 -0400 | [diff] [blame] | 1323 | { |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1324 | bool need_lookup; |
Al Viro | a325554 | 2012-03-30 14:41:51 -0400 | [diff] [blame] | 1325 | struct dentry *dentry; |
| 1326 | |
Al Viro | 72bd866 | 2012-06-10 17:17:17 -0400 | [diff] [blame] | 1327 | dentry = lookup_dcache(name, base, flags, &need_lookup); |
Miklos Szeredi | bad6118 | 2012-03-26 12:54:24 +0200 | [diff] [blame] | 1328 | if (!need_lookup) |
| 1329 | return dentry; |
Al Viro | a325554 | 2012-03-30 14:41:51 -0400 | [diff] [blame] | 1330 | |
Al Viro | 72bd866 | 2012-06-10 17:17:17 -0400 | [diff] [blame] | 1331 | return lookup_real(base->d_inode, dentry, flags); |
Al Viro | a325554 | 2012-03-30 14:41:51 -0400 | [diff] [blame] | 1332 | } |
| 1333 | |
Josef Bacik | 44396f4 | 2011-05-31 11:58:49 -0400 | [diff] [blame] | 1334 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1335 | * It's more convoluted than I'd like it to be, but... it's still fairly |
| 1336 | * small and for now I'd prefer to have fast path as straight as possible. |
| 1337 | * It _is_ time-critical. |
| 1338 | */ |
Al Viro | e97cdc8 | 2013-01-24 18:16:00 -0500 | [diff] [blame] | 1339 | static int lookup_fast(struct nameidata *nd, |
Miklos Szeredi | 697f514 | 2012-05-21 17:30:05 +0200 | [diff] [blame] | 1340 | struct path *path, struct inode **inode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1341 | { |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 1342 | struct vfsmount *mnt = nd->path.mnt; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1343 | struct dentry *dentry, *parent = nd->path.dentry; |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1344 | int need_reval = 1; |
| 1345 | int status = 1; |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1346 | int err; |
| 1347 | |
Al Viro | 3cac260 | 2009-08-13 18:27:43 +0400 | [diff] [blame] | 1348 | /* |
Nick Piggin | b04f784 | 2010-08-18 04:37:34 +1000 | [diff] [blame] | 1349 | * Rename seqlock is not required here because in the off chance |
| 1350 | * of a false negative due to a concurrent rename, we're going to |
| 1351 | * do the non-racy lookup, below. |
| 1352 | */ |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1353 | if (nd->flags & LOOKUP_RCU) { |
| 1354 | unsigned seq; |
Linus Torvalds | da53be1 | 2013-05-21 15:22:44 -0700 | [diff] [blame] | 1355 | dentry = __d_lookup_rcu(parent, &nd->last, &seq); |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1356 | if (!dentry) |
| 1357 | goto unlazy; |
| 1358 | |
Linus Torvalds | 12f8ad4 | 2012-05-04 14:59:14 -0700 | [diff] [blame] | 1359 | /* |
| 1360 | * This sequence count validates that the inode matches |
| 1361 | * the dentry name information from lookup. |
| 1362 | */ |
| 1363 | *inode = dentry->d_inode; |
| 1364 | if (read_seqcount_retry(&dentry->d_seq, seq)) |
| 1365 | return -ECHILD; |
| 1366 | |
| 1367 | /* |
| 1368 | * This sequence count validates that the parent had no |
| 1369 | * changes while we did the lookup of the dentry above. |
| 1370 | * |
| 1371 | * The memory barrier in read_seqcount_begin of child is |
| 1372 | * enough, we can use __read_seqcount_retry here. |
| 1373 | */ |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1374 | if (__read_seqcount_retry(&parent->d_seq, nd->seq)) |
| 1375 | return -ECHILD; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1376 | nd->seq = seq; |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1377 | |
Al Viro | 2464308 | 2011-02-15 01:26:22 -0500 | [diff] [blame] | 1378 | if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE)) { |
Al Viro | 4ce16ef3 | 2012-06-10 16:10:59 -0400 | [diff] [blame] | 1379 | status = d_revalidate(dentry, nd->flags); |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1380 | if (unlikely(status <= 0)) { |
| 1381 | if (status != -ECHILD) |
| 1382 | need_reval = 0; |
| 1383 | goto unlazy; |
| 1384 | } |
Al Viro | 2464308 | 2011-02-15 01:26:22 -0500 | [diff] [blame] | 1385 | } |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1386 | path->mnt = mnt; |
| 1387 | path->dentry = dentry; |
Al Viro | d6e9bd2 | 2011-05-27 07:03:15 -0400 | [diff] [blame] | 1388 | if (unlikely(!__follow_mount_rcu(nd, path, inode))) |
| 1389 | goto unlazy; |
| 1390 | if (unlikely(path->dentry->d_flags & DCACHE_NEED_AUTOMOUNT)) |
| 1391 | goto unlazy; |
| 1392 | return 0; |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1393 | unlazy: |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 1394 | if (unlazy_walk(nd, dentry)) |
| 1395 | return -ECHILD; |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1396 | } else { |
Al Viro | e97cdc8 | 2013-01-24 18:16:00 -0500 | [diff] [blame] | 1397 | dentry = __d_lookup(parent, &nd->last); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1398 | } |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1399 | |
Al Viro | 81e6f52 | 2012-03-30 14:48:04 -0400 | [diff] [blame] | 1400 | if (unlikely(!dentry)) |
| 1401 | goto need_lookup; |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1402 | |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1403 | if (unlikely(dentry->d_flags & DCACHE_OP_REVALIDATE) && need_reval) |
Al Viro | 4ce16ef3 | 2012-06-10 16:10:59 -0400 | [diff] [blame] | 1404 | status = d_revalidate(dentry, nd->flags); |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1405 | if (unlikely(status <= 0)) { |
| 1406 | if (status < 0) { |
| 1407 | dput(dentry); |
| 1408 | return status; |
| 1409 | } |
| 1410 | if (!d_invalidate(dentry)) { |
| 1411 | dput(dentry); |
Al Viro | 81e6f52 | 2012-03-30 14:48:04 -0400 | [diff] [blame] | 1412 | goto need_lookup; |
Al Viro | 5a18fff | 2011-03-11 04:44:53 -0500 | [diff] [blame] | 1413 | } |
| 1414 | } |
Miklos Szeredi | 697f514 | 2012-05-21 17:30:05 +0200 | [diff] [blame] | 1415 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1416 | path->mnt = mnt; |
| 1417 | path->dentry = dentry; |
| 1418 | err = follow_managed(path, nd->flags); |
Ian Kent | 8931221 | 2011-01-18 12:06:10 +0800 | [diff] [blame] | 1419 | if (unlikely(err < 0)) { |
| 1420 | path_put_conditional(path, nd); |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1421 | return err; |
Ian Kent | 8931221 | 2011-01-18 12:06:10 +0800 | [diff] [blame] | 1422 | } |
Al Viro | a3fbbde | 2011-11-07 21:21:26 +0000 | [diff] [blame] | 1423 | if (err) |
| 1424 | nd->flags |= LOOKUP_JUMPED; |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 1425 | *inode = path->dentry->d_inode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1426 | return 0; |
Al Viro | 81e6f52 | 2012-03-30 14:48:04 -0400 | [diff] [blame] | 1427 | |
| 1428 | need_lookup: |
Miklos Szeredi | 697f514 | 2012-05-21 17:30:05 +0200 | [diff] [blame] | 1429 | return 1; |
| 1430 | } |
| 1431 | |
| 1432 | /* Fast lookup failed, do it the slow way */ |
Al Viro | cc2a527 | 2013-01-24 18:19:49 -0500 | [diff] [blame] | 1433 | static int lookup_slow(struct nameidata *nd, struct path *path) |
Miklos Szeredi | 697f514 | 2012-05-21 17:30:05 +0200 | [diff] [blame] | 1434 | { |
| 1435 | struct dentry *dentry, *parent; |
| 1436 | int err; |
| 1437 | |
| 1438 | parent = nd->path.dentry; |
Al Viro | 81e6f52 | 2012-03-30 14:48:04 -0400 | [diff] [blame] | 1439 | BUG_ON(nd->inode != parent->d_inode); |
| 1440 | |
| 1441 | mutex_lock(&parent->d_inode->i_mutex); |
Al Viro | cc2a527 | 2013-01-24 18:19:49 -0500 | [diff] [blame] | 1442 | dentry = __lookup_hash(&nd->last, parent, nd->flags); |
Al Viro | 81e6f52 | 2012-03-30 14:48:04 -0400 | [diff] [blame] | 1443 | mutex_unlock(&parent->d_inode->i_mutex); |
| 1444 | if (IS_ERR(dentry)) |
| 1445 | return PTR_ERR(dentry); |
Miklos Szeredi | 697f514 | 2012-05-21 17:30:05 +0200 | [diff] [blame] | 1446 | path->mnt = nd->path.mnt; |
| 1447 | path->dentry = dentry; |
| 1448 | err = follow_managed(path, nd->flags); |
| 1449 | if (unlikely(err < 0)) { |
| 1450 | path_put_conditional(path, nd); |
| 1451 | return err; |
| 1452 | } |
| 1453 | if (err) |
| 1454 | nd->flags |= LOOKUP_JUMPED; |
| 1455 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1456 | } |
| 1457 | |
Al Viro | 52094c8 | 2011-02-21 21:34:47 -0500 | [diff] [blame] | 1458 | static inline int may_lookup(struct nameidata *nd) |
| 1459 | { |
| 1460 | if (nd->flags & LOOKUP_RCU) { |
Al Viro | 4ad5abb | 2011-06-20 19:57:03 -0400 | [diff] [blame] | 1461 | int err = inode_permission(nd->inode, MAY_EXEC|MAY_NOT_BLOCK); |
Al Viro | 52094c8 | 2011-02-21 21:34:47 -0500 | [diff] [blame] | 1462 | if (err != -ECHILD) |
| 1463 | return err; |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 1464 | if (unlazy_walk(nd, NULL)) |
Al Viro | 52094c8 | 2011-02-21 21:34:47 -0500 | [diff] [blame] | 1465 | return -ECHILD; |
| 1466 | } |
Al Viro | 4ad5abb | 2011-06-20 19:57:03 -0400 | [diff] [blame] | 1467 | return inode_permission(nd->inode, MAY_EXEC); |
Al Viro | 52094c8 | 2011-02-21 21:34:47 -0500 | [diff] [blame] | 1468 | } |
| 1469 | |
Al Viro | 9856fa1 | 2011-03-04 14:22:06 -0500 | [diff] [blame] | 1470 | static inline int handle_dots(struct nameidata *nd, int type) |
| 1471 | { |
| 1472 | if (type == LAST_DOTDOT) { |
| 1473 | if (nd->flags & LOOKUP_RCU) { |
| 1474 | if (follow_dotdot_rcu(nd)) |
| 1475 | return -ECHILD; |
| 1476 | } else |
| 1477 | follow_dotdot(nd); |
| 1478 | } |
| 1479 | return 0; |
| 1480 | } |
| 1481 | |
Al Viro | 951361f | 2011-03-04 14:44:37 -0500 | [diff] [blame] | 1482 | static void terminate_walk(struct nameidata *nd) |
| 1483 | { |
| 1484 | if (!(nd->flags & LOOKUP_RCU)) { |
| 1485 | path_put(&nd->path); |
| 1486 | } else { |
| 1487 | nd->flags &= ~LOOKUP_RCU; |
Al Viro | 5b6ca02 | 2011-03-09 23:04:47 -0500 | [diff] [blame] | 1488 | if (!(nd->flags & LOOKUP_ROOT)) |
| 1489 | nd->root.mnt = NULL; |
Al Viro | 32a7991 | 2012-07-18 20:43:19 +0400 | [diff] [blame] | 1490 | unlock_rcu_walk(); |
Al Viro | 951361f | 2011-03-04 14:44:37 -0500 | [diff] [blame] | 1491 | } |
| 1492 | } |
| 1493 | |
Linus Torvalds | 3ddcd05 | 2011-08-06 22:45:50 -0700 | [diff] [blame] | 1494 | /* |
| 1495 | * Do we need to follow links? We _really_ want to be able |
| 1496 | * to do this check without having to look at inode->i_op, |
| 1497 | * so we keep a cache of "no, this doesn't need follow_link" |
| 1498 | * for the common case. |
| 1499 | */ |
Linus Torvalds | 7813b94 | 2011-08-07 09:53:20 -0700 | [diff] [blame] | 1500 | static inline int should_follow_link(struct inode *inode, int follow) |
Linus Torvalds | 3ddcd05 | 2011-08-06 22:45:50 -0700 | [diff] [blame] | 1501 | { |
| 1502 | if (unlikely(!(inode->i_opflags & IOP_NOFOLLOW))) { |
| 1503 | if (likely(inode->i_op->follow_link)) |
| 1504 | return follow; |
| 1505 | |
| 1506 | /* This gets set once for the inode lifetime */ |
| 1507 | spin_lock(&inode->i_lock); |
| 1508 | inode->i_opflags |= IOP_NOFOLLOW; |
| 1509 | spin_unlock(&inode->i_lock); |
| 1510 | } |
| 1511 | return 0; |
| 1512 | } |
| 1513 | |
Al Viro | ce57dfc | 2011-03-13 19:58:58 -0400 | [diff] [blame] | 1514 | static inline int walk_component(struct nameidata *nd, struct path *path, |
Al Viro | 21b9b07 | 2013-01-24 18:10:25 -0500 | [diff] [blame] | 1515 | int follow) |
Al Viro | ce57dfc | 2011-03-13 19:58:58 -0400 | [diff] [blame] | 1516 | { |
| 1517 | struct inode *inode; |
| 1518 | int err; |
| 1519 | /* |
| 1520 | * "." and ".." are special - ".." especially so because it has |
| 1521 | * to be able to know about the current root directory and |
| 1522 | * parent relationships. |
| 1523 | */ |
Al Viro | 21b9b07 | 2013-01-24 18:10:25 -0500 | [diff] [blame] | 1524 | if (unlikely(nd->last_type != LAST_NORM)) |
| 1525 | return handle_dots(nd, nd->last_type); |
Al Viro | e97cdc8 | 2013-01-24 18:16:00 -0500 | [diff] [blame] | 1526 | err = lookup_fast(nd, path, &inode); |
Al Viro | ce57dfc | 2011-03-13 19:58:58 -0400 | [diff] [blame] | 1527 | if (unlikely(err)) { |
Miklos Szeredi | 697f514 | 2012-05-21 17:30:05 +0200 | [diff] [blame] | 1528 | if (err < 0) |
| 1529 | goto out_err; |
| 1530 | |
Al Viro | cc2a527 | 2013-01-24 18:19:49 -0500 | [diff] [blame] | 1531 | err = lookup_slow(nd, path); |
Miklos Szeredi | 697f514 | 2012-05-21 17:30:05 +0200 | [diff] [blame] | 1532 | if (err < 0) |
| 1533 | goto out_err; |
| 1534 | |
| 1535 | inode = path->dentry->d_inode; |
Al Viro | ce57dfc | 2011-03-13 19:58:58 -0400 | [diff] [blame] | 1536 | } |
Miklos Szeredi | 697f514 | 2012-05-21 17:30:05 +0200 | [diff] [blame] | 1537 | err = -ENOENT; |
| 1538 | if (!inode) |
| 1539 | goto out_path_put; |
| 1540 | |
Linus Torvalds | 7813b94 | 2011-08-07 09:53:20 -0700 | [diff] [blame] | 1541 | if (should_follow_link(inode, follow)) { |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 1542 | if (nd->flags & LOOKUP_RCU) { |
| 1543 | if (unlikely(unlazy_walk(nd, path->dentry))) { |
Miklos Szeredi | 697f514 | 2012-05-21 17:30:05 +0200 | [diff] [blame] | 1544 | err = -ECHILD; |
| 1545 | goto out_err; |
Al Viro | 19660af | 2011-03-25 10:32:48 -0400 | [diff] [blame] | 1546 | } |
| 1547 | } |
Al Viro | ce57dfc | 2011-03-13 19:58:58 -0400 | [diff] [blame] | 1548 | BUG_ON(inode != path->dentry->d_inode); |
| 1549 | return 1; |
| 1550 | } |
| 1551 | path_to_nameidata(path, nd); |
| 1552 | nd->inode = inode; |
| 1553 | return 0; |
Miklos Szeredi | 697f514 | 2012-05-21 17:30:05 +0200 | [diff] [blame] | 1554 | |
| 1555 | out_path_put: |
| 1556 | path_to_nameidata(path, nd); |
| 1557 | out_err: |
| 1558 | terminate_walk(nd); |
| 1559 | return err; |
Al Viro | ce57dfc | 2011-03-13 19:58:58 -0400 | [diff] [blame] | 1560 | } |
| 1561 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1562 | /* |
Al Viro | b356379 | 2011-03-14 21:54:55 -0400 | [diff] [blame] | 1563 | * This limits recursive symlink follows to 8, while |
| 1564 | * limiting consecutive symlinks to 40. |
| 1565 | * |
| 1566 | * Without that kind of total limit, nasty chains of consecutive |
| 1567 | * symlinks can cause almost arbitrarily long lookups. |
| 1568 | */ |
| 1569 | static inline int nested_symlink(struct path *path, struct nameidata *nd) |
| 1570 | { |
| 1571 | int res; |
| 1572 | |
Al Viro | b356379 | 2011-03-14 21:54:55 -0400 | [diff] [blame] | 1573 | if (unlikely(current->link_count >= MAX_NESTED_LINKS)) { |
| 1574 | path_put_conditional(path, nd); |
| 1575 | path_put(&nd->path); |
| 1576 | return -ELOOP; |
| 1577 | } |
Erez Zadok | 1a4022f | 2011-05-21 01:19:59 -0400 | [diff] [blame] | 1578 | BUG_ON(nd->depth >= MAX_NESTED_LINKS); |
Al Viro | b356379 | 2011-03-14 21:54:55 -0400 | [diff] [blame] | 1579 | |
| 1580 | nd->depth++; |
| 1581 | current->link_count++; |
| 1582 | |
| 1583 | do { |
| 1584 | struct path link = *path; |
| 1585 | void *cookie; |
Al Viro | 574197e | 2011-03-14 22:20:34 -0400 | [diff] [blame] | 1586 | |
| 1587 | res = follow_link(&link, nd, &cookie); |
Al Viro | 6d7b5aa | 2012-06-10 04:15:17 -0400 | [diff] [blame] | 1588 | if (res) |
| 1589 | break; |
Al Viro | 21b9b07 | 2013-01-24 18:10:25 -0500 | [diff] [blame] | 1590 | res = walk_component(nd, path, LOOKUP_FOLLOW); |
Al Viro | 574197e | 2011-03-14 22:20:34 -0400 | [diff] [blame] | 1591 | put_link(nd, &link, cookie); |
Al Viro | b356379 | 2011-03-14 21:54:55 -0400 | [diff] [blame] | 1592 | } while (res > 0); |
| 1593 | |
| 1594 | current->link_count--; |
| 1595 | nd->depth--; |
| 1596 | return res; |
| 1597 | } |
| 1598 | |
| 1599 | /* |
Linus Torvalds | 3ddcd05 | 2011-08-06 22:45:50 -0700 | [diff] [blame] | 1600 | * We really don't want to look at inode->i_op->lookup |
| 1601 | * when we don't have to. So we keep a cache bit in |
| 1602 | * the inode ->i_opflags field that says "yes, we can |
| 1603 | * do lookup on this inode". |
| 1604 | */ |
| 1605 | static inline int can_lookup(struct inode *inode) |
| 1606 | { |
| 1607 | if (likely(inode->i_opflags & IOP_LOOKUP)) |
| 1608 | return 1; |
| 1609 | if (likely(!inode->i_op->lookup)) |
| 1610 | return 0; |
| 1611 | |
| 1612 | /* We do this once for the lifetime of the inode */ |
| 1613 | spin_lock(&inode->i_lock); |
| 1614 | inode->i_opflags |= IOP_LOOKUP; |
| 1615 | spin_unlock(&inode->i_lock); |
| 1616 | return 1; |
| 1617 | } |
| 1618 | |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1619 | /* |
| 1620 | * We can do the critical dentry name comparison and hashing |
| 1621 | * operations one word at a time, but we are limited to: |
| 1622 | * |
| 1623 | * - Architectures with fast unaligned word accesses. We could |
| 1624 | * do a "get_unaligned()" if this helps and is sufficiently |
| 1625 | * fast. |
| 1626 | * |
| 1627 | * - Little-endian machines (so that we can generate the mask |
| 1628 | * of low bytes efficiently). Again, we *could* do a byte |
| 1629 | * swapping load on big-endian architectures if that is not |
| 1630 | * expensive enough to make the optimization worthless. |
| 1631 | * |
| 1632 | * - non-CONFIG_DEBUG_PAGEALLOC configurations (so that we |
| 1633 | * do not trap on the (extremely unlikely) case of a page |
| 1634 | * crossing operation. |
| 1635 | * |
| 1636 | * - Furthermore, we need an efficient 64-bit compile for the |
| 1637 | * 64-bit case in order to generate the "number of bytes in |
| 1638 | * the final mask". Again, that could be replaced with a |
| 1639 | * efficient population count instruction or similar. |
| 1640 | */ |
| 1641 | #ifdef CONFIG_DCACHE_WORD_ACCESS |
| 1642 | |
Linus Torvalds | f68e556 | 2012-04-06 13:54:56 -0700 | [diff] [blame] | 1643 | #include <asm/word-at-a-time.h> |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1644 | |
Linus Torvalds | f68e556 | 2012-04-06 13:54:56 -0700 | [diff] [blame] | 1645 | #ifdef CONFIG_64BIT |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1646 | |
| 1647 | static inline unsigned int fold_hash(unsigned long hash) |
| 1648 | { |
| 1649 | hash += hash >> (8*sizeof(int)); |
| 1650 | return hash; |
| 1651 | } |
| 1652 | |
| 1653 | #else /* 32-bit case */ |
| 1654 | |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1655 | #define fold_hash(x) (x) |
| 1656 | |
| 1657 | #endif |
| 1658 | |
| 1659 | unsigned int full_name_hash(const unsigned char *name, unsigned int len) |
| 1660 | { |
| 1661 | unsigned long a, mask; |
| 1662 | unsigned long hash = 0; |
| 1663 | |
| 1664 | for (;;) { |
Linus Torvalds | e419b4c | 2012-05-03 10:16:43 -0700 | [diff] [blame] | 1665 | a = load_unaligned_zeropad(name); |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1666 | if (len < sizeof(unsigned long)) |
| 1667 | break; |
| 1668 | hash += a; |
Al Viro | f132c5b | 2012-03-22 21:59:52 +0000 | [diff] [blame] | 1669 | hash *= 9; |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1670 | name += sizeof(unsigned long); |
| 1671 | len -= sizeof(unsigned long); |
| 1672 | if (!len) |
| 1673 | goto done; |
| 1674 | } |
| 1675 | mask = ~(~0ul << len*8); |
| 1676 | hash += mask & a; |
| 1677 | done: |
| 1678 | return fold_hash(hash); |
| 1679 | } |
| 1680 | EXPORT_SYMBOL(full_name_hash); |
| 1681 | |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1682 | /* |
| 1683 | * Calculate the length and hash of the path component, and |
| 1684 | * return the length of the component; |
| 1685 | */ |
| 1686 | static inline unsigned long hash_name(const char *name, unsigned int *hashp) |
| 1687 | { |
Linus Torvalds | 36126f8 | 2012-05-26 10:43:17 -0700 | [diff] [blame] | 1688 | unsigned long a, b, adata, bdata, mask, hash, len; |
| 1689 | const struct word_at_a_time constants = WORD_AT_A_TIME_CONSTANTS; |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1690 | |
| 1691 | hash = a = 0; |
| 1692 | len = -sizeof(unsigned long); |
| 1693 | do { |
| 1694 | hash = (hash + a) * 9; |
| 1695 | len += sizeof(unsigned long); |
Linus Torvalds | e419b4c | 2012-05-03 10:16:43 -0700 | [diff] [blame] | 1696 | a = load_unaligned_zeropad(name+len); |
Linus Torvalds | 36126f8 | 2012-05-26 10:43:17 -0700 | [diff] [blame] | 1697 | b = a ^ REPEAT_BYTE('/'); |
| 1698 | } while (!(has_zero(a, &adata, &constants) | has_zero(b, &bdata, &constants))); |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1699 | |
Linus Torvalds | 36126f8 | 2012-05-26 10:43:17 -0700 | [diff] [blame] | 1700 | adata = prep_zero_mask(a, adata, &constants); |
| 1701 | bdata = prep_zero_mask(b, bdata, &constants); |
| 1702 | |
| 1703 | mask = create_zero_mask(adata | bdata); |
| 1704 | |
| 1705 | hash += a & zero_bytemask(mask); |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1706 | *hashp = fold_hash(hash); |
| 1707 | |
Linus Torvalds | 36126f8 | 2012-05-26 10:43:17 -0700 | [diff] [blame] | 1708 | return len + find_zero(mask); |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1709 | } |
| 1710 | |
| 1711 | #else |
| 1712 | |
Linus Torvalds | 0145acc | 2012-03-02 14:32:59 -0800 | [diff] [blame] | 1713 | unsigned int full_name_hash(const unsigned char *name, unsigned int len) |
| 1714 | { |
| 1715 | unsigned long hash = init_name_hash(); |
| 1716 | while (len--) |
| 1717 | hash = partial_name_hash(*name++, hash); |
| 1718 | return end_name_hash(hash); |
| 1719 | } |
Linus Torvalds | ae942ae | 2012-03-02 19:40:57 -0800 | [diff] [blame] | 1720 | EXPORT_SYMBOL(full_name_hash); |
Linus Torvalds | 0145acc | 2012-03-02 14:32:59 -0800 | [diff] [blame] | 1721 | |
Linus Torvalds | 3ddcd05 | 2011-08-06 22:45:50 -0700 | [diff] [blame] | 1722 | /* |
Linus Torvalds | 200e9ef | 2012-03-02 14:49:24 -0800 | [diff] [blame] | 1723 | * We know there's a real path component here of at least |
| 1724 | * one character. |
| 1725 | */ |
| 1726 | static inline unsigned long hash_name(const char *name, unsigned int *hashp) |
| 1727 | { |
| 1728 | unsigned long hash = init_name_hash(); |
| 1729 | unsigned long len = 0, c; |
| 1730 | |
| 1731 | c = (unsigned char)*name; |
| 1732 | do { |
| 1733 | len++; |
| 1734 | hash = partial_name_hash(c, hash); |
| 1735 | c = (unsigned char)name[len]; |
| 1736 | } while (c && c != '/'); |
| 1737 | *hashp = end_name_hash(hash); |
| 1738 | return len; |
| 1739 | } |
| 1740 | |
Linus Torvalds | bfcfaa7 | 2012-03-06 11:16:17 -0800 | [diff] [blame] | 1741 | #endif |
| 1742 | |
Linus Torvalds | 200e9ef | 2012-03-02 14:49:24 -0800 | [diff] [blame] | 1743 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1744 | * Name resolution. |
Prasanna Meda | ea3834d | 2005-04-29 16:00:17 +0100 | [diff] [blame] | 1745 | * This is the basic name resolution function, turning a pathname into |
| 1746 | * the final dentry. We expect 'base' to be positive and a directory. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1747 | * |
Prasanna Meda | ea3834d | 2005-04-29 16:00:17 +0100 | [diff] [blame] | 1748 | * Returns 0 and nd will have valid dentry and mnt on success. |
| 1749 | * Returns error and drops reference to input namei data on failure. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1750 | */ |
Al Viro | 6de88d7 | 2009-08-09 01:41:57 +0400 | [diff] [blame] | 1751 | static int link_path_walk(const char *name, struct nameidata *nd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1752 | { |
| 1753 | struct path next; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1754 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1755 | |
| 1756 | while (*name=='/') |
| 1757 | name++; |
| 1758 | if (!*name) |
Al Viro | 086e183 | 2011-02-22 20:56:27 -0500 | [diff] [blame] | 1759 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1760 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1761 | /* At this point we know we have a real path component. */ |
| 1762 | for(;;) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1763 | struct qstr this; |
Linus Torvalds | 200e9ef | 2012-03-02 14:49:24 -0800 | [diff] [blame] | 1764 | long len; |
Al Viro | fe479a5 | 2011-02-22 15:10:03 -0500 | [diff] [blame] | 1765 | int type; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1766 | |
Al Viro | 52094c8 | 2011-02-21 21:34:47 -0500 | [diff] [blame] | 1767 | err = may_lookup(nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1768 | if (err) |
| 1769 | break; |
| 1770 | |
Linus Torvalds | 200e9ef | 2012-03-02 14:49:24 -0800 | [diff] [blame] | 1771 | len = hash_name(name, &this.hash); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1772 | this.name = name; |
Linus Torvalds | 200e9ef | 2012-03-02 14:49:24 -0800 | [diff] [blame] | 1773 | this.len = len; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1774 | |
Al Viro | fe479a5 | 2011-02-22 15:10:03 -0500 | [diff] [blame] | 1775 | type = LAST_NORM; |
Linus Torvalds | 200e9ef | 2012-03-02 14:49:24 -0800 | [diff] [blame] | 1776 | if (name[0] == '.') switch (len) { |
Al Viro | fe479a5 | 2011-02-22 15:10:03 -0500 | [diff] [blame] | 1777 | case 2: |
Linus Torvalds | 200e9ef | 2012-03-02 14:49:24 -0800 | [diff] [blame] | 1778 | if (name[1] == '.') { |
Al Viro | fe479a5 | 2011-02-22 15:10:03 -0500 | [diff] [blame] | 1779 | type = LAST_DOTDOT; |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 1780 | nd->flags |= LOOKUP_JUMPED; |
| 1781 | } |
Al Viro | fe479a5 | 2011-02-22 15:10:03 -0500 | [diff] [blame] | 1782 | break; |
| 1783 | case 1: |
| 1784 | type = LAST_DOT; |
| 1785 | } |
Al Viro | 5a202bc | 2011-03-08 14:17:44 -0500 | [diff] [blame] | 1786 | if (likely(type == LAST_NORM)) { |
| 1787 | struct dentry *parent = nd->path.dentry; |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 1788 | nd->flags &= ~LOOKUP_JUMPED; |
Al Viro | 5a202bc | 2011-03-08 14:17:44 -0500 | [diff] [blame] | 1789 | if (unlikely(parent->d_flags & DCACHE_OP_HASH)) { |
Linus Torvalds | da53be1 | 2013-05-21 15:22:44 -0700 | [diff] [blame] | 1790 | err = parent->d_op->d_hash(parent, &this); |
Al Viro | 5a202bc | 2011-03-08 14:17:44 -0500 | [diff] [blame] | 1791 | if (err < 0) |
| 1792 | break; |
| 1793 | } |
| 1794 | } |
Al Viro | fe479a5 | 2011-02-22 15:10:03 -0500 | [diff] [blame] | 1795 | |
Al Viro | 5f4a6a6 | 2013-01-24 18:04:22 -0500 | [diff] [blame] | 1796 | nd->last = this; |
| 1797 | nd->last_type = type; |
| 1798 | |
Linus Torvalds | 200e9ef | 2012-03-02 14:49:24 -0800 | [diff] [blame] | 1799 | if (!name[len]) |
Al Viro | 5f4a6a6 | 2013-01-24 18:04:22 -0500 | [diff] [blame] | 1800 | return 0; |
Linus Torvalds | 200e9ef | 2012-03-02 14:49:24 -0800 | [diff] [blame] | 1801 | /* |
| 1802 | * If it wasn't NUL, we know it was '/'. Skip that |
| 1803 | * slash, and continue until no more slashes. |
| 1804 | */ |
| 1805 | do { |
| 1806 | len++; |
| 1807 | } while (unlikely(name[len] == '/')); |
| 1808 | if (!name[len]) |
Al Viro | 5f4a6a6 | 2013-01-24 18:04:22 -0500 | [diff] [blame] | 1809 | return 0; |
| 1810 | |
Linus Torvalds | 200e9ef | 2012-03-02 14:49:24 -0800 | [diff] [blame] | 1811 | name += len; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1812 | |
Al Viro | 21b9b07 | 2013-01-24 18:10:25 -0500 | [diff] [blame] | 1813 | err = walk_component(nd, &next, LOOKUP_FOLLOW); |
Al Viro | ce57dfc | 2011-03-13 19:58:58 -0400 | [diff] [blame] | 1814 | if (err < 0) |
| 1815 | return err; |
Al Viro | fe479a5 | 2011-02-22 15:10:03 -0500 | [diff] [blame] | 1816 | |
Al Viro | ce57dfc | 2011-03-13 19:58:58 -0400 | [diff] [blame] | 1817 | if (err) { |
Al Viro | b356379 | 2011-03-14 21:54:55 -0400 | [diff] [blame] | 1818 | err = nested_symlink(&next, nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1819 | if (err) |
Al Viro | a7472ba | 2011-03-04 14:39:30 -0500 | [diff] [blame] | 1820 | return err; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1821 | } |
Al Viro | 5f4a6a6 | 2013-01-24 18:04:22 -0500 | [diff] [blame] | 1822 | if (!can_lookup(nd->inode)) { |
| 1823 | err = -ENOTDIR; |
| 1824 | break; |
| 1825 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1826 | } |
Al Viro | 951361f | 2011-03-04 14:44:37 -0500 | [diff] [blame] | 1827 | terminate_walk(nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1828 | return err; |
| 1829 | } |
| 1830 | |
Al Viro | 70e9b35 | 2011-03-05 21:12:22 -0500 | [diff] [blame] | 1831 | static int path_init(int dfd, const char *name, unsigned int flags, |
| 1832 | struct nameidata *nd, struct file **fp) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1833 | { |
Prasanna Meda | ea3834d | 2005-04-29 16:00:17 +0100 | [diff] [blame] | 1834 | int retval = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1835 | |
| 1836 | nd->last_type = LAST_ROOT; /* if there are only slashes... */ |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 1837 | nd->flags = flags | LOOKUP_JUMPED; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1838 | nd->depth = 0; |
Al Viro | 5b6ca02 | 2011-03-09 23:04:47 -0500 | [diff] [blame] | 1839 | if (flags & LOOKUP_ROOT) { |
| 1840 | struct inode *inode = nd->root.dentry->d_inode; |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 1841 | if (*name) { |
Al Viro | 741b7c3 | 2012-12-20 13:41:28 -0500 | [diff] [blame] | 1842 | if (!can_lookup(inode)) |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 1843 | return -ENOTDIR; |
| 1844 | retval = inode_permission(inode, MAY_EXEC); |
| 1845 | if (retval) |
| 1846 | return retval; |
| 1847 | } |
Al Viro | 5b6ca02 | 2011-03-09 23:04:47 -0500 | [diff] [blame] | 1848 | nd->path = nd->root; |
| 1849 | nd->inode = inode; |
| 1850 | if (flags & LOOKUP_RCU) { |
Al Viro | 32a7991 | 2012-07-18 20:43:19 +0400 | [diff] [blame] | 1851 | lock_rcu_walk(); |
Al Viro | 5b6ca02 | 2011-03-09 23:04:47 -0500 | [diff] [blame] | 1852 | nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq); |
| 1853 | } else { |
| 1854 | path_get(&nd->path); |
| 1855 | } |
| 1856 | return 0; |
| 1857 | } |
| 1858 | |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 1859 | nd->root.mnt = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1860 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1861 | if (*name=='/') { |
Al Viro | e41f7d4 | 2011-02-22 14:02:58 -0500 | [diff] [blame] | 1862 | if (flags & LOOKUP_RCU) { |
Al Viro | 32a7991 | 2012-07-18 20:43:19 +0400 | [diff] [blame] | 1863 | lock_rcu_walk(); |
Al Viro | e41f7d4 | 2011-02-22 14:02:58 -0500 | [diff] [blame] | 1864 | set_root_rcu(nd); |
| 1865 | } else { |
| 1866 | set_root(nd); |
| 1867 | path_get(&nd->root); |
| 1868 | } |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 1869 | nd->path = nd->root; |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 1870 | } else if (dfd == AT_FDCWD) { |
Al Viro | e41f7d4 | 2011-02-22 14:02:58 -0500 | [diff] [blame] | 1871 | if (flags & LOOKUP_RCU) { |
| 1872 | struct fs_struct *fs = current->fs; |
| 1873 | unsigned seq; |
| 1874 | |
Al Viro | 32a7991 | 2012-07-18 20:43:19 +0400 | [diff] [blame] | 1875 | lock_rcu_walk(); |
Al Viro | e41f7d4 | 2011-02-22 14:02:58 -0500 | [diff] [blame] | 1876 | |
| 1877 | do { |
| 1878 | seq = read_seqcount_begin(&fs->seq); |
| 1879 | nd->path = fs->pwd; |
| 1880 | nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq); |
| 1881 | } while (read_seqcount_retry(&fs->seq, seq)); |
| 1882 | } else { |
| 1883 | get_fs_pwd(current->fs, &nd->path); |
| 1884 | } |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 1885 | } else { |
Jeff Layton | 582aa64 | 2012-12-11 08:56:16 -0500 | [diff] [blame] | 1886 | /* Caller must check execute permissions on the starting path component */ |
Al Viro | 2903ff0 | 2012-08-28 12:52:22 -0400 | [diff] [blame] | 1887 | struct fd f = fdget_raw(dfd); |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 1888 | struct dentry *dentry; |
| 1889 | |
Al Viro | 2903ff0 | 2012-08-28 12:52:22 -0400 | [diff] [blame] | 1890 | if (!f.file) |
| 1891 | return -EBADF; |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 1892 | |
Al Viro | 2903ff0 | 2012-08-28 12:52:22 -0400 | [diff] [blame] | 1893 | dentry = f.file->f_path.dentry; |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 1894 | |
Al Viro | f52e0c1 | 2011-03-14 18:56:51 -0400 | [diff] [blame] | 1895 | if (*name) { |
Al Viro | 741b7c3 | 2012-12-20 13:41:28 -0500 | [diff] [blame] | 1896 | if (!can_lookup(dentry->d_inode)) { |
Al Viro | 2903ff0 | 2012-08-28 12:52:22 -0400 | [diff] [blame] | 1897 | fdput(f); |
| 1898 | return -ENOTDIR; |
| 1899 | } |
Al Viro | f52e0c1 | 2011-03-14 18:56:51 -0400 | [diff] [blame] | 1900 | } |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 1901 | |
Al Viro | 2903ff0 | 2012-08-28 12:52:22 -0400 | [diff] [blame] | 1902 | nd->path = f.file->f_path; |
Al Viro | e41f7d4 | 2011-02-22 14:02:58 -0500 | [diff] [blame] | 1903 | if (flags & LOOKUP_RCU) { |
Al Viro | 2903ff0 | 2012-08-28 12:52:22 -0400 | [diff] [blame] | 1904 | if (f.need_put) |
| 1905 | *fp = f.file; |
Al Viro | e41f7d4 | 2011-02-22 14:02:58 -0500 | [diff] [blame] | 1906 | nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq); |
Al Viro | 32a7991 | 2012-07-18 20:43:19 +0400 | [diff] [blame] | 1907 | lock_rcu_walk(); |
Al Viro | e41f7d4 | 2011-02-22 14:02:58 -0500 | [diff] [blame] | 1908 | } else { |
Al Viro | 2903ff0 | 2012-08-28 12:52:22 -0400 | [diff] [blame] | 1909 | path_get(&nd->path); |
| 1910 | fdput(f); |
Al Viro | e41f7d4 | 2011-02-22 14:02:58 -0500 | [diff] [blame] | 1911 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1912 | } |
Al Viro | e41f7d4 | 2011-02-22 14:02:58 -0500 | [diff] [blame] | 1913 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1914 | nd->inode = nd->path.dentry->d_inode; |
Al Viro | 9b4a9b1 | 2009-04-07 11:44:16 -0400 | [diff] [blame] | 1915 | return 0; |
Al Viro | 9b4a9b1 | 2009-04-07 11:44:16 -0400 | [diff] [blame] | 1916 | } |
| 1917 | |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 1918 | static inline int lookup_last(struct nameidata *nd, struct path *path) |
| 1919 | { |
| 1920 | if (nd->last_type == LAST_NORM && nd->last.name[nd->last.len]) |
| 1921 | nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY; |
| 1922 | |
| 1923 | nd->flags &= ~LOOKUP_PARENT; |
Al Viro | 21b9b07 | 2013-01-24 18:10:25 -0500 | [diff] [blame] | 1924 | return walk_component(nd, path, nd->flags & LOOKUP_FOLLOW); |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 1925 | } |
| 1926 | |
Al Viro | 9b4a9b1 | 2009-04-07 11:44:16 -0400 | [diff] [blame] | 1927 | /* Returns 0 and nd will be valid on success; Retuns error, otherwise. */ |
Al Viro | ee0827c | 2011-02-21 23:38:09 -0500 | [diff] [blame] | 1928 | static int path_lookupat(int dfd, const char *name, |
Al Viro | 9b4a9b1 | 2009-04-07 11:44:16 -0400 | [diff] [blame] | 1929 | unsigned int flags, struct nameidata *nd) |
| 1930 | { |
Al Viro | 70e9b35 | 2011-03-05 21:12:22 -0500 | [diff] [blame] | 1931 | struct file *base = NULL; |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 1932 | struct path path; |
| 1933 | int err; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1934 | |
| 1935 | /* |
| 1936 | * Path walking is largely split up into 2 different synchronisation |
| 1937 | * schemes, rcu-walk and ref-walk (explained in |
| 1938 | * Documentation/filesystems/path-lookup.txt). These share much of the |
| 1939 | * path walk code, but some things particularly setup, cleanup, and |
| 1940 | * following mounts are sufficiently divergent that functions are |
| 1941 | * duplicated. Typically there is a function foo(), and its RCU |
| 1942 | * analogue, foo_rcu(). |
| 1943 | * |
| 1944 | * -ECHILD is the error number of choice (just to avoid clashes) that |
| 1945 | * is returned if some aspect of an rcu-walk fails. Such an error must |
| 1946 | * be handled by restarting a traditional ref-walk (which will always |
| 1947 | * be able to complete). |
| 1948 | */ |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 1949 | err = path_init(dfd, name, flags | LOOKUP_PARENT, nd, &base); |
Al Viro | ee0827c | 2011-02-21 23:38:09 -0500 | [diff] [blame] | 1950 | |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 1951 | if (unlikely(err)) |
| 1952 | return err; |
Al Viro | ee0827c | 2011-02-21 23:38:09 -0500 | [diff] [blame] | 1953 | |
| 1954 | current->total_link_count = 0; |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 1955 | err = link_path_walk(name, nd); |
| 1956 | |
| 1957 | if (!err && !(flags & LOOKUP_PARENT)) { |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 1958 | err = lookup_last(nd, &path); |
| 1959 | while (err > 0) { |
| 1960 | void *cookie; |
| 1961 | struct path link = path; |
Kees Cook | 800179c | 2012-07-25 17:29:07 -0700 | [diff] [blame] | 1962 | err = may_follow_link(&link, nd); |
| 1963 | if (unlikely(err)) |
| 1964 | break; |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 1965 | nd->flags |= LOOKUP_PARENT; |
Al Viro | 574197e | 2011-03-14 22:20:34 -0400 | [diff] [blame] | 1966 | err = follow_link(&link, nd, &cookie); |
Al Viro | 6d7b5aa | 2012-06-10 04:15:17 -0400 | [diff] [blame] | 1967 | if (err) |
| 1968 | break; |
| 1969 | err = lookup_last(nd, &path); |
Al Viro | 574197e | 2011-03-14 22:20:34 -0400 | [diff] [blame] | 1970 | put_link(nd, &link, cookie); |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 1971 | } |
| 1972 | } |
Al Viro | ee0827c | 2011-02-21 23:38:09 -0500 | [diff] [blame] | 1973 | |
Al Viro | 9f1fafe | 2011-03-25 11:00:12 -0400 | [diff] [blame] | 1974 | if (!err) |
| 1975 | err = complete_walk(nd); |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 1976 | |
| 1977 | if (!err && nd->flags & LOOKUP_DIRECTORY) { |
Al Viro | 0525290 | 2013-06-06 19:33:47 -0400 | [diff] [blame] | 1978 | if (!can_lookup(nd->inode)) { |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 1979 | path_put(&nd->path); |
Al Viro | bd23a53 | 2011-03-23 09:56:30 -0400 | [diff] [blame] | 1980 | err = -ENOTDIR; |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 1981 | } |
| 1982 | } |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 1983 | |
Al Viro | 70e9b35 | 2011-03-05 21:12:22 -0500 | [diff] [blame] | 1984 | if (base) |
| 1985 | fput(base); |
Al Viro | ee0827c | 2011-02-21 23:38:09 -0500 | [diff] [blame] | 1986 | |
Al Viro | 5b6ca02 | 2011-03-09 23:04:47 -0500 | [diff] [blame] | 1987 | if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT)) { |
Al Viro | 2a73787 | 2009-04-07 11:49:53 -0400 | [diff] [blame] | 1988 | path_put(&nd->root); |
| 1989 | nd->root.mnt = NULL; |
| 1990 | } |
Al Viro | bd92d7f | 2011-03-14 19:54:59 -0400 | [diff] [blame] | 1991 | return err; |
Al Viro | ee0827c | 2011-02-21 23:38:09 -0500 | [diff] [blame] | 1992 | } |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 1993 | |
Jeff Layton | 873f1ee | 2012-10-10 15:25:29 -0400 | [diff] [blame] | 1994 | static int filename_lookup(int dfd, struct filename *name, |
| 1995 | unsigned int flags, struct nameidata *nd) |
| 1996 | { |
| 1997 | int retval = path_lookupat(dfd, name->name, flags | LOOKUP_RCU, nd); |
| 1998 | if (unlikely(retval == -ECHILD)) |
| 1999 | retval = path_lookupat(dfd, name->name, flags, nd); |
| 2000 | if (unlikely(retval == -ESTALE)) |
| 2001 | retval = path_lookupat(dfd, name->name, |
| 2002 | flags | LOOKUP_REVAL, nd); |
| 2003 | |
| 2004 | if (likely(!retval)) |
Jeff Layton | adb5c24 | 2012-10-10 16:43:13 -0400 | [diff] [blame] | 2005 | audit_inode(name, nd->path.dentry, flags & LOOKUP_PARENT); |
Jeff Layton | 873f1ee | 2012-10-10 15:25:29 -0400 | [diff] [blame] | 2006 | return retval; |
| 2007 | } |
| 2008 | |
Al Viro | ee0827c | 2011-02-21 23:38:09 -0500 | [diff] [blame] | 2009 | static int do_path_lookup(int dfd, const char *name, |
| 2010 | unsigned int flags, struct nameidata *nd) |
| 2011 | { |
Jeff Layton | 873f1ee | 2012-10-10 15:25:29 -0400 | [diff] [blame] | 2012 | struct filename filename = { .name = name }; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2013 | |
Jeff Layton | 873f1ee | 2012-10-10 15:25:29 -0400 | [diff] [blame] | 2014 | return filename_lookup(dfd, &filename, flags, nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2015 | } |
| 2016 | |
Al Viro | 79714f7 | 2012-06-15 03:01:42 +0400 | [diff] [blame] | 2017 | /* does lookup, returns the object with parent locked */ |
| 2018 | struct dentry *kern_path_locked(const char *name, struct path *path) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2019 | { |
Al Viro | 79714f7 | 2012-06-15 03:01:42 +0400 | [diff] [blame] | 2020 | struct nameidata nd; |
| 2021 | struct dentry *d; |
| 2022 | int err = do_path_lookup(AT_FDCWD, name, LOOKUP_PARENT, &nd); |
| 2023 | if (err) |
| 2024 | return ERR_PTR(err); |
| 2025 | if (nd.last_type != LAST_NORM) { |
| 2026 | path_put(&nd.path); |
| 2027 | return ERR_PTR(-EINVAL); |
| 2028 | } |
| 2029 | mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); |
Al Viro | 1e0ea00 | 2012-07-22 23:46:21 +0400 | [diff] [blame] | 2030 | d = __lookup_hash(&nd.last, nd.path.dentry, 0); |
Al Viro | 79714f7 | 2012-06-15 03:01:42 +0400 | [diff] [blame] | 2031 | if (IS_ERR(d)) { |
| 2032 | mutex_unlock(&nd.path.dentry->d_inode->i_mutex); |
| 2033 | path_put(&nd.path); |
| 2034 | return d; |
| 2035 | } |
| 2036 | *path = nd.path; |
| 2037 | return d; |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 2038 | } |
| 2039 | |
Al Viro | d181146 | 2008-08-02 00:49:18 -0400 | [diff] [blame] | 2040 | int kern_path(const char *name, unsigned int flags, struct path *path) |
| 2041 | { |
| 2042 | struct nameidata nd; |
| 2043 | int res = do_path_lookup(AT_FDCWD, name, flags, &nd); |
| 2044 | if (!res) |
| 2045 | *path = nd.path; |
| 2046 | return res; |
| 2047 | } |
| 2048 | |
Josef 'Jeff' Sipek | 16f1820 | 2007-07-19 01:48:18 -0700 | [diff] [blame] | 2049 | /** |
| 2050 | * vfs_path_lookup - lookup a file path relative to a dentry-vfsmount pair |
| 2051 | * @dentry: pointer to dentry of the base directory |
| 2052 | * @mnt: pointer to vfs mount of the base directory |
| 2053 | * @name: pointer to file name |
| 2054 | * @flags: lookup flags |
Al Viro | e0a0124 | 2011-06-27 17:00:37 -0400 | [diff] [blame] | 2055 | * @path: pointer to struct path to fill |
Josef 'Jeff' Sipek | 16f1820 | 2007-07-19 01:48:18 -0700 | [diff] [blame] | 2056 | */ |
| 2057 | int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt, |
| 2058 | const char *name, unsigned int flags, |
Al Viro | e0a0124 | 2011-06-27 17:00:37 -0400 | [diff] [blame] | 2059 | struct path *path) |
Josef 'Jeff' Sipek | 16f1820 | 2007-07-19 01:48:18 -0700 | [diff] [blame] | 2060 | { |
Al Viro | e0a0124 | 2011-06-27 17:00:37 -0400 | [diff] [blame] | 2061 | struct nameidata nd; |
| 2062 | int err; |
| 2063 | nd.root.dentry = dentry; |
| 2064 | nd.root.mnt = mnt; |
| 2065 | BUG_ON(flags & LOOKUP_PARENT); |
Al Viro | 5b6ca02 | 2011-03-09 23:04:47 -0500 | [diff] [blame] | 2066 | /* the first argument of do_path_lookup() is ignored with LOOKUP_ROOT */ |
Al Viro | e0a0124 | 2011-06-27 17:00:37 -0400 | [diff] [blame] | 2067 | err = do_path_lookup(AT_FDCWD, name, flags | LOOKUP_ROOT, &nd); |
| 2068 | if (!err) |
| 2069 | *path = nd.path; |
| 2070 | return err; |
Josef 'Jeff' Sipek | 16f1820 | 2007-07-19 01:48:18 -0700 | [diff] [blame] | 2071 | } |
| 2072 | |
James Morris | 057f6c0 | 2007-04-26 00:12:05 -0700 | [diff] [blame] | 2073 | /* |
| 2074 | * Restricted form of lookup. Doesn't follow links, single-component only, |
| 2075 | * needs parent already locked. Doesn't follow mounts. |
| 2076 | * SMP-safe. |
| 2077 | */ |
Adrian Bunk | a244e16 | 2006-03-31 02:32:11 -0800 | [diff] [blame] | 2078 | static struct dentry *lookup_hash(struct nameidata *nd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2079 | { |
Al Viro | 72bd866 | 2012-06-10 17:17:17 -0400 | [diff] [blame] | 2080 | return __lookup_hash(&nd->last, nd->path.dentry, nd->flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2081 | } |
| 2082 | |
Christoph Hellwig | eead191 | 2007-10-16 23:25:38 -0700 | [diff] [blame] | 2083 | /** |
Randy Dunlap | a6b9191 | 2008-03-19 17:01:00 -0700 | [diff] [blame] | 2084 | * lookup_one_len - filesystem helper to lookup single pathname component |
Christoph Hellwig | eead191 | 2007-10-16 23:25:38 -0700 | [diff] [blame] | 2085 | * @name: pathname component to lookup |
| 2086 | * @base: base directory to lookup from |
| 2087 | * @len: maximum length @len should be interpreted to |
| 2088 | * |
Randy Dunlap | a6b9191 | 2008-03-19 17:01:00 -0700 | [diff] [blame] | 2089 | * Note that this routine is purely a helper for filesystem usage and should |
| 2090 | * not be called by generic code. Also note that by using this function the |
Christoph Hellwig | eead191 | 2007-10-16 23:25:38 -0700 | [diff] [blame] | 2091 | * nameidata argument is passed to the filesystem methods and a filesystem |
| 2092 | * using this helper needs to be prepared for that. |
| 2093 | */ |
James Morris | 057f6c0 | 2007-04-26 00:12:05 -0700 | [diff] [blame] | 2094 | struct dentry *lookup_one_len(const char *name, struct dentry *base, int len) |
| 2095 | { |
James Morris | 057f6c0 | 2007-04-26 00:12:05 -0700 | [diff] [blame] | 2096 | struct qstr this; |
Al Viro | 6a96ba5 | 2011-03-07 23:49:20 -0500 | [diff] [blame] | 2097 | unsigned int c; |
Miklos Szeredi | cda309d | 2012-03-26 12:54:21 +0200 | [diff] [blame] | 2098 | int err; |
James Morris | 057f6c0 | 2007-04-26 00:12:05 -0700 | [diff] [blame] | 2099 | |
David Woodhouse | 2f9092e | 2009-04-20 23:18:37 +0100 | [diff] [blame] | 2100 | WARN_ON_ONCE(!mutex_is_locked(&base->d_inode->i_mutex)); |
| 2101 | |
Al Viro | 6a96ba5 | 2011-03-07 23:49:20 -0500 | [diff] [blame] | 2102 | this.name = name; |
| 2103 | this.len = len; |
Linus Torvalds | 0145acc | 2012-03-02 14:32:59 -0800 | [diff] [blame] | 2104 | this.hash = full_name_hash(name, len); |
Al Viro | 6a96ba5 | 2011-03-07 23:49:20 -0500 | [diff] [blame] | 2105 | if (!len) |
| 2106 | return ERR_PTR(-EACCES); |
| 2107 | |
Al Viro | 21d8a15 | 2012-11-29 22:17:21 -0500 | [diff] [blame] | 2108 | if (unlikely(name[0] == '.')) { |
| 2109 | if (len < 2 || (len == 2 && name[1] == '.')) |
| 2110 | return ERR_PTR(-EACCES); |
| 2111 | } |
| 2112 | |
Al Viro | 6a96ba5 | 2011-03-07 23:49:20 -0500 | [diff] [blame] | 2113 | while (len--) { |
| 2114 | c = *(const unsigned char *)name++; |
| 2115 | if (c == '/' || c == '\0') |
| 2116 | return ERR_PTR(-EACCES); |
Al Viro | 6a96ba5 | 2011-03-07 23:49:20 -0500 | [diff] [blame] | 2117 | } |
Al Viro | 5a202bc | 2011-03-08 14:17:44 -0500 | [diff] [blame] | 2118 | /* |
| 2119 | * See if the low-level filesystem might want |
| 2120 | * to use its own hash.. |
| 2121 | */ |
| 2122 | if (base->d_flags & DCACHE_OP_HASH) { |
Linus Torvalds | da53be1 | 2013-05-21 15:22:44 -0700 | [diff] [blame] | 2123 | int err = base->d_op->d_hash(base, &this); |
Al Viro | 5a202bc | 2011-03-08 14:17:44 -0500 | [diff] [blame] | 2124 | if (err < 0) |
| 2125 | return ERR_PTR(err); |
| 2126 | } |
Christoph Hellwig | eead191 | 2007-10-16 23:25:38 -0700 | [diff] [blame] | 2127 | |
Miklos Szeredi | cda309d | 2012-03-26 12:54:21 +0200 | [diff] [blame] | 2128 | err = inode_permission(base->d_inode, MAY_EXEC); |
| 2129 | if (err) |
| 2130 | return ERR_PTR(err); |
| 2131 | |
Al Viro | 72bd866 | 2012-06-10 17:17:17 -0400 | [diff] [blame] | 2132 | return __lookup_hash(&this, base, 0); |
James Morris | 057f6c0 | 2007-04-26 00:12:05 -0700 | [diff] [blame] | 2133 | } |
| 2134 | |
Andy Whitcroft | 1fa1e7f | 2011-11-02 09:44:39 +0100 | [diff] [blame] | 2135 | int user_path_at_empty(int dfd, const char __user *name, unsigned flags, |
| 2136 | struct path *path, int *empty) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2137 | { |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 2138 | struct nameidata nd; |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 2139 | struct filename *tmp = getname_flags(name, flags, empty); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2140 | int err = PTR_ERR(tmp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2141 | if (!IS_ERR(tmp)) { |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 2142 | |
| 2143 | BUG_ON(flags & LOOKUP_PARENT); |
| 2144 | |
Jeff Layton | 873f1ee | 2012-10-10 15:25:29 -0400 | [diff] [blame] | 2145 | err = filename_lookup(dfd, tmp, flags, &nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2146 | putname(tmp); |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 2147 | if (!err) |
| 2148 | *path = nd.path; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2149 | } |
| 2150 | return err; |
| 2151 | } |
| 2152 | |
Andy Whitcroft | 1fa1e7f | 2011-11-02 09:44:39 +0100 | [diff] [blame] | 2153 | int user_path_at(int dfd, const char __user *name, unsigned flags, |
| 2154 | struct path *path) |
| 2155 | { |
Linus Torvalds | f7493e5 | 2012-03-22 16:10:40 -0700 | [diff] [blame] | 2156 | return user_path_at_empty(dfd, name, flags, path, NULL); |
Andy Whitcroft | 1fa1e7f | 2011-11-02 09:44:39 +0100 | [diff] [blame] | 2157 | } |
| 2158 | |
Jeff Layton | 873f1ee | 2012-10-10 15:25:29 -0400 | [diff] [blame] | 2159 | /* |
| 2160 | * NB: most callers don't do anything directly with the reference to the |
| 2161 | * to struct filename, but the nd->last pointer points into the name string |
| 2162 | * allocated by getname. So we must hold the reference to it until all |
| 2163 | * path-walking is complete. |
| 2164 | */ |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 2165 | static struct filename * |
Jeff Layton | 9e790bd | 2012-12-11 12:10:09 -0500 | [diff] [blame] | 2166 | user_path_parent(int dfd, const char __user *path, struct nameidata *nd, |
| 2167 | unsigned int flags) |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2168 | { |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 2169 | struct filename *s = getname(path); |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2170 | int error; |
| 2171 | |
Jeff Layton | 9e790bd | 2012-12-11 12:10:09 -0500 | [diff] [blame] | 2172 | /* only LOOKUP_REVAL is allowed in extra flags */ |
| 2173 | flags &= LOOKUP_REVAL; |
| 2174 | |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2175 | if (IS_ERR(s)) |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 2176 | return s; |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2177 | |
Jeff Layton | 9e790bd | 2012-12-11 12:10:09 -0500 | [diff] [blame] | 2178 | error = filename_lookup(dfd, s, flags | LOOKUP_PARENT, nd); |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 2179 | if (error) { |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2180 | putname(s); |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 2181 | return ERR_PTR(error); |
| 2182 | } |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2183 | |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 2184 | return s; |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 2185 | } |
| 2186 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2187 | /* |
| 2188 | * It's inline, so penalty for filesystems that don't use sticky bit is |
| 2189 | * minimal. |
| 2190 | */ |
| 2191 | static inline int check_sticky(struct inode *dir, struct inode *inode) |
| 2192 | { |
Eric W. Biederman | 8e96e3b | 2012-03-03 21:17:15 -0800 | [diff] [blame] | 2193 | kuid_t fsuid = current_fsuid(); |
David Howells | da9592e | 2008-11-14 10:39:05 +1100 | [diff] [blame] | 2194 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2195 | if (!(dir->i_mode & S_ISVTX)) |
| 2196 | return 0; |
Eric W. Biederman | 8e96e3b | 2012-03-03 21:17:15 -0800 | [diff] [blame] | 2197 | if (uid_eq(inode->i_uid, fsuid)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2198 | return 0; |
Eric W. Biederman | 8e96e3b | 2012-03-03 21:17:15 -0800 | [diff] [blame] | 2199 | if (uid_eq(dir->i_uid, fsuid)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2200 | return 0; |
Eric W. Biederman | 1a48e2a | 2011-11-14 16:24:06 -0800 | [diff] [blame] | 2201 | return !inode_capable(inode, CAP_FOWNER); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2202 | } |
| 2203 | |
| 2204 | /* |
| 2205 | * Check whether we can remove a link victim from directory dir, check |
| 2206 | * whether the type of victim is right. |
| 2207 | * 1. We can't do it if dir is read-only (done in permission()) |
| 2208 | * 2. We should have write and exec permissions on dir |
| 2209 | * 3. We can't remove anything from append-only dir |
| 2210 | * 4. We can't do anything with immutable dir (done in permission()) |
| 2211 | * 5. If the sticky bit on dir is set we should either |
| 2212 | * a. be owner of dir, or |
| 2213 | * b. be owner of victim, or |
| 2214 | * c. have CAP_FOWNER capability |
| 2215 | * 6. If the victim is append-only or immutable we can't do antyhing with |
| 2216 | * links pointing to it. |
| 2217 | * 7. If we were asked to remove a directory and victim isn't one - ENOTDIR. |
| 2218 | * 8. If we were asked to remove a non-directory and victim isn't one - EISDIR. |
| 2219 | * 9. We can't remove a root or mountpoint. |
| 2220 | * 10. We don't allow removal of NFS sillyrenamed files; it's handled by |
| 2221 | * nfs_async_unlink(). |
| 2222 | */ |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame] | 2223 | static int may_delete(struct inode *dir,struct dentry *victim,int isdir) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2224 | { |
| 2225 | int error; |
| 2226 | |
| 2227 | if (!victim->d_inode) |
| 2228 | return -ENOENT; |
| 2229 | |
| 2230 | BUG_ON(victim->d_parent->d_inode != dir); |
Jeff Layton | 4fa6b5e | 2012-10-10 15:25:25 -0400 | [diff] [blame] | 2231 | audit_inode_child(dir, victim, AUDIT_TYPE_CHILD_DELETE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2232 | |
Al Viro | f419a2e | 2008-07-22 00:07:17 -0400 | [diff] [blame] | 2233 | error = inode_permission(dir, MAY_WRITE | MAY_EXEC); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2234 | if (error) |
| 2235 | return error; |
| 2236 | if (IS_APPEND(dir)) |
| 2237 | return -EPERM; |
| 2238 | if (check_sticky(dir, victim->d_inode)||IS_APPEND(victim->d_inode)|| |
Hugh Dickins | f945454 | 2008-11-19 15:36:38 -0800 | [diff] [blame] | 2239 | IS_IMMUTABLE(victim->d_inode) || IS_SWAPFILE(victim->d_inode)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2240 | return -EPERM; |
| 2241 | if (isdir) { |
| 2242 | if (!S_ISDIR(victim->d_inode->i_mode)) |
| 2243 | return -ENOTDIR; |
| 2244 | if (IS_ROOT(victim)) |
| 2245 | return -EBUSY; |
| 2246 | } else if (S_ISDIR(victim->d_inode->i_mode)) |
| 2247 | return -EISDIR; |
| 2248 | if (IS_DEADDIR(dir)) |
| 2249 | return -ENOENT; |
| 2250 | if (victim->d_flags & DCACHE_NFSFS_RENAMED) |
| 2251 | return -EBUSY; |
| 2252 | return 0; |
| 2253 | } |
| 2254 | |
| 2255 | /* Check whether we can create an object with dentry child in directory |
| 2256 | * dir. |
| 2257 | * 1. We can't do it if child already exists (open has special treatment for |
| 2258 | * this case, but since we are inlined it's OK) |
| 2259 | * 2. We can't do it if dir is read-only (done in permission()) |
| 2260 | * 3. We should have write and exec permissions on dir |
| 2261 | * 4. We can't do it if dir is immutable (done in permission()) |
| 2262 | */ |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 2263 | static inline int may_create(struct inode *dir, struct dentry *child) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2264 | { |
| 2265 | if (child->d_inode) |
| 2266 | return -EEXIST; |
| 2267 | if (IS_DEADDIR(dir)) |
| 2268 | return -ENOENT; |
Al Viro | f419a2e | 2008-07-22 00:07:17 -0400 | [diff] [blame] | 2269 | return inode_permission(dir, MAY_WRITE | MAY_EXEC); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2270 | } |
| 2271 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2272 | /* |
| 2273 | * p1 and p2 should be directories on the same fs. |
| 2274 | */ |
| 2275 | struct dentry *lock_rename(struct dentry *p1, struct dentry *p2) |
| 2276 | { |
| 2277 | struct dentry *p; |
| 2278 | |
| 2279 | if (p1 == p2) { |
Ingo Molnar | f2eace2 | 2006-07-03 00:25:05 -0700 | [diff] [blame] | 2280 | mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2281 | return NULL; |
| 2282 | } |
| 2283 | |
Arjan van de Ven | a11f3a0 | 2006-03-23 03:00:33 -0800 | [diff] [blame] | 2284 | mutex_lock(&p1->d_inode->i_sb->s_vfs_rename_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2285 | |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2286 | p = d_ancestor(p2, p1); |
| 2287 | if (p) { |
| 2288 | mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_PARENT); |
| 2289 | mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_CHILD); |
| 2290 | return p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2291 | } |
| 2292 | |
OGAWA Hirofumi | e2761a1 | 2008-10-16 07:50:28 +0900 | [diff] [blame] | 2293 | p = d_ancestor(p1, p2); |
| 2294 | if (p) { |
| 2295 | mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); |
| 2296 | mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD); |
| 2297 | return p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2298 | } |
| 2299 | |
Ingo Molnar | f2eace2 | 2006-07-03 00:25:05 -0700 | [diff] [blame] | 2300 | mutex_lock_nested(&p1->d_inode->i_mutex, I_MUTEX_PARENT); |
| 2301 | mutex_lock_nested(&p2->d_inode->i_mutex, I_MUTEX_CHILD); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2302 | return NULL; |
| 2303 | } |
| 2304 | |
| 2305 | void unlock_rename(struct dentry *p1, struct dentry *p2) |
| 2306 | { |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 2307 | mutex_unlock(&p1->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2308 | if (p1 != p2) { |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 2309 | mutex_unlock(&p2->d_inode->i_mutex); |
Arjan van de Ven | a11f3a0 | 2006-03-23 03:00:33 -0800 | [diff] [blame] | 2310 | mutex_unlock(&p1->d_inode->i_sb->s_vfs_rename_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2311 | } |
| 2312 | } |
| 2313 | |
Al Viro | 4acdaf2 | 2011-07-26 01:42:34 -0400 | [diff] [blame] | 2314 | int vfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, |
Al Viro | 312b63f | 2012-06-10 18:09:36 -0400 | [diff] [blame] | 2315 | bool want_excl) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2316 | { |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 2317 | int error = may_create(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2318 | if (error) |
| 2319 | return error; |
| 2320 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 2321 | if (!dir->i_op->create) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2322 | return -EACCES; /* shouldn't it be ENOSYS? */ |
| 2323 | mode &= S_IALLUGO; |
| 2324 | mode |= S_IFREG; |
| 2325 | error = security_inode_create(dir, dentry, mode); |
| 2326 | if (error) |
| 2327 | return error; |
Al Viro | 312b63f | 2012-06-10 18:09:36 -0400 | [diff] [blame] | 2328 | error = dir->i_op->create(dir, dentry, mode, want_excl); |
Stephen Smalley | a74574a | 2005-09-09 13:01:44 -0700 | [diff] [blame] | 2329 | if (!error) |
Amy Griffis | f38aa94 | 2005-11-03 15:57:06 +0000 | [diff] [blame] | 2330 | fsnotify_create(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2331 | return error; |
| 2332 | } |
| 2333 | |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 2334 | static int may_open(struct path *path, int acc_mode, int flag) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2335 | { |
Christoph Hellwig | 3fb6419 | 2008-10-24 09:58:10 +0200 | [diff] [blame] | 2336 | struct dentry *dentry = path->dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2337 | struct inode *inode = dentry->d_inode; |
| 2338 | int error; |
| 2339 | |
Al Viro | bcda765 | 2011-03-13 16:42:14 -0400 | [diff] [blame] | 2340 | /* O_PATH? */ |
| 2341 | if (!acc_mode) |
| 2342 | return 0; |
| 2343 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2344 | if (!inode) |
| 2345 | return -ENOENT; |
| 2346 | |
Christoph Hellwig | c8fe8f3 | 2009-01-05 19:27:23 +0100 | [diff] [blame] | 2347 | switch (inode->i_mode & S_IFMT) { |
| 2348 | case S_IFLNK: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2349 | return -ELOOP; |
Christoph Hellwig | c8fe8f3 | 2009-01-05 19:27:23 +0100 | [diff] [blame] | 2350 | case S_IFDIR: |
| 2351 | if (acc_mode & MAY_WRITE) |
| 2352 | return -EISDIR; |
| 2353 | break; |
| 2354 | case S_IFBLK: |
| 2355 | case S_IFCHR: |
Christoph Hellwig | 3fb6419 | 2008-10-24 09:58:10 +0200 | [diff] [blame] | 2356 | if (path->mnt->mnt_flags & MNT_NODEV) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2357 | return -EACCES; |
Christoph Hellwig | c8fe8f3 | 2009-01-05 19:27:23 +0100 | [diff] [blame] | 2358 | /*FALLTHRU*/ |
| 2359 | case S_IFIFO: |
| 2360 | case S_IFSOCK: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2361 | flag &= ~O_TRUNC; |
Christoph Hellwig | c8fe8f3 | 2009-01-05 19:27:23 +0100 | [diff] [blame] | 2362 | break; |
Dave Hansen | 4a3fd21 | 2008-02-15 14:37:48 -0800 | [diff] [blame] | 2363 | } |
Dave Hansen | b41572e | 2007-10-16 23:31:14 -0700 | [diff] [blame] | 2364 | |
Christoph Hellwig | 3fb6419 | 2008-10-24 09:58:10 +0200 | [diff] [blame] | 2365 | error = inode_permission(inode, acc_mode); |
Dave Hansen | b41572e | 2007-10-16 23:31:14 -0700 | [diff] [blame] | 2366 | if (error) |
| 2367 | return error; |
Mimi Zohar | 6146f0d | 2009-02-04 09:06:57 -0500 | [diff] [blame] | 2368 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2369 | /* |
| 2370 | * An append-only file must be opened in append mode for writing. |
| 2371 | */ |
| 2372 | if (IS_APPEND(inode)) { |
Al Viro | 8737c93 | 2009-12-24 06:47:55 -0500 | [diff] [blame] | 2373 | if ((flag & O_ACCMODE) != O_RDONLY && !(flag & O_APPEND)) |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 2374 | return -EPERM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2375 | if (flag & O_TRUNC) |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 2376 | return -EPERM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2377 | } |
| 2378 | |
| 2379 | /* O_NOATIME can only be set by the owner or superuser */ |
Serge E. Hallyn | 2e14967 | 2011-03-23 16:43:26 -0700 | [diff] [blame] | 2380 | if (flag & O_NOATIME && !inode_owner_or_capable(inode)) |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 2381 | return -EPERM; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2382 | |
J. Bruce Fields | f3c7691e | 2011-09-21 10:58:13 -0400 | [diff] [blame] | 2383 | return 0; |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 2384 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2385 | |
Jeff Layton | e1181ee | 2010-12-07 16:19:50 -0500 | [diff] [blame] | 2386 | static int handle_truncate(struct file *filp) |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 2387 | { |
Jeff Layton | e1181ee | 2010-12-07 16:19:50 -0500 | [diff] [blame] | 2388 | struct path *path = &filp->f_path; |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 2389 | struct inode *inode = path->dentry->d_inode; |
| 2390 | int error = get_write_access(inode); |
| 2391 | if (error) |
| 2392 | return error; |
| 2393 | /* |
| 2394 | * Refuse to truncate files with mandatory locks held on them. |
| 2395 | */ |
| 2396 | error = locks_verify_locked(inode); |
| 2397 | if (!error) |
Tetsuo Handa | ea0d3ab | 2010-06-02 13:24:43 +0900 | [diff] [blame] | 2398 | error = security_path_truncate(path); |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 2399 | if (!error) { |
| 2400 | error = do_truncate(path->dentry, 0, |
| 2401 | ATTR_MTIME|ATTR_CTIME|ATTR_OPEN, |
Jeff Layton | e1181ee | 2010-12-07 16:19:50 -0500 | [diff] [blame] | 2402 | filp); |
Al Viro | 7715b52 | 2009-12-16 03:54:00 -0500 | [diff] [blame] | 2403 | } |
| 2404 | put_write_access(inode); |
Mimi Zohar | acd0c93 | 2009-09-04 13:08:46 -0400 | [diff] [blame] | 2405 | return error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2406 | } |
| 2407 | |
Dave Hansen | d57999e | 2008-02-15 14:37:27 -0800 | [diff] [blame] | 2408 | static inline int open_to_namei_flags(int flag) |
| 2409 | { |
Al Viro | 8a5e929 | 2011-06-25 19:15:54 -0400 | [diff] [blame] | 2410 | if ((flag & O_ACCMODE) == 3) |
| 2411 | flag--; |
Dave Hansen | d57999e | 2008-02-15 14:37:27 -0800 | [diff] [blame] | 2412 | return flag; |
| 2413 | } |
| 2414 | |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2415 | static int may_o_create(struct path *dir, struct dentry *dentry, umode_t mode) |
| 2416 | { |
| 2417 | int error = security_path_mknod(dir, dentry, mode, 0); |
| 2418 | if (error) |
| 2419 | return error; |
| 2420 | |
| 2421 | error = inode_permission(dir->dentry->d_inode, MAY_WRITE | MAY_EXEC); |
| 2422 | if (error) |
| 2423 | return error; |
| 2424 | |
| 2425 | return security_inode_create(dir->dentry->d_inode, dentry, mode); |
| 2426 | } |
| 2427 | |
David Howells | 1acf0af | 2012-06-14 16:13:46 +0100 | [diff] [blame] | 2428 | /* |
| 2429 | * Attempt to atomically look up, create and open a file from a negative |
| 2430 | * dentry. |
| 2431 | * |
| 2432 | * Returns 0 if successful. The file will have been created and attached to |
| 2433 | * @file by the filesystem calling finish_open(). |
| 2434 | * |
| 2435 | * Returns 1 if the file was looked up only or didn't need creating. The |
| 2436 | * caller will need to perform the open themselves. @path will have been |
| 2437 | * updated to point to the new dentry. This may be negative. |
| 2438 | * |
| 2439 | * Returns an error code otherwise. |
| 2440 | */ |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2441 | static int atomic_open(struct nameidata *nd, struct dentry *dentry, |
| 2442 | struct path *path, struct file *file, |
| 2443 | const struct open_flags *op, |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 2444 | bool got_write, bool need_lookup, |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2445 | int *opened) |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2446 | { |
| 2447 | struct inode *dir = nd->path.dentry->d_inode; |
| 2448 | unsigned open_flag = open_to_namei_flags(op->open_flag); |
| 2449 | umode_t mode; |
| 2450 | int error; |
| 2451 | int acc_mode; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2452 | int create_error = 0; |
| 2453 | struct dentry *const DENTRY_NOT_SET = (void *) -1UL; |
| 2454 | |
| 2455 | BUG_ON(dentry->d_inode); |
| 2456 | |
| 2457 | /* Don't create child dentry for a dead directory. */ |
| 2458 | if (unlikely(IS_DEADDIR(dir))) { |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2459 | error = -ENOENT; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2460 | goto out; |
| 2461 | } |
| 2462 | |
Miklos Szeredi | 62b259d | 2012-08-15 13:01:24 +0200 | [diff] [blame] | 2463 | mode = op->mode; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2464 | if ((open_flag & O_CREAT) && !IS_POSIXACL(dir)) |
| 2465 | mode &= ~current_umask(); |
| 2466 | |
Al Viro | f8310c5 | 2012-07-30 11:50:30 +0400 | [diff] [blame] | 2467 | if ((open_flag & (O_EXCL | O_CREAT)) == (O_EXCL | O_CREAT)) { |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2468 | open_flag &= ~O_TRUNC; |
Al Viro | 4723768 | 2012-06-10 05:01:45 -0400 | [diff] [blame] | 2469 | *opened |= FILE_CREATED; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2470 | } |
| 2471 | |
| 2472 | /* |
| 2473 | * Checking write permission is tricky, bacuse we don't know if we are |
| 2474 | * going to actually need it: O_CREAT opens should work as long as the |
| 2475 | * file exists. But checking existence breaks atomicity. The trick is |
| 2476 | * to check access and if not granted clear O_CREAT from the flags. |
| 2477 | * |
| 2478 | * Another problem is returing the "right" error value (e.g. for an |
| 2479 | * O_EXCL open we want to return EEXIST not EROFS). |
| 2480 | */ |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 2481 | if (((open_flag & (O_CREAT | O_TRUNC)) || |
| 2482 | (open_flag & O_ACCMODE) != O_RDONLY) && unlikely(!got_write)) { |
| 2483 | if (!(open_flag & O_CREAT)) { |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2484 | /* |
| 2485 | * No O_CREATE -> atomicity not a requirement -> fall |
| 2486 | * back to lookup + open |
| 2487 | */ |
| 2488 | goto no_open; |
| 2489 | } else if (open_flag & (O_EXCL | O_TRUNC)) { |
| 2490 | /* Fall back and fail with the right error */ |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 2491 | create_error = -EROFS; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2492 | goto no_open; |
| 2493 | } else { |
| 2494 | /* No side effects, safe to clear O_CREAT */ |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 2495 | create_error = -EROFS; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2496 | open_flag &= ~O_CREAT; |
| 2497 | } |
| 2498 | } |
| 2499 | |
| 2500 | if (open_flag & O_CREAT) { |
Miklos Szeredi | 38227f7 | 2012-08-15 13:01:24 +0200 | [diff] [blame] | 2501 | error = may_o_create(&nd->path, dentry, mode); |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2502 | if (error) { |
| 2503 | create_error = error; |
| 2504 | if (open_flag & O_EXCL) |
| 2505 | goto no_open; |
| 2506 | open_flag &= ~O_CREAT; |
| 2507 | } |
| 2508 | } |
| 2509 | |
| 2510 | if (nd->flags & LOOKUP_DIRECTORY) |
| 2511 | open_flag |= O_DIRECTORY; |
| 2512 | |
Al Viro | 30d9049 | 2012-06-22 12:40:19 +0400 | [diff] [blame] | 2513 | file->f_path.dentry = DENTRY_NOT_SET; |
| 2514 | file->f_path.mnt = nd->path.mnt; |
| 2515 | error = dir->i_op->atomic_open(dir, dentry, file, open_flag, mode, |
Al Viro | 4723768 | 2012-06-10 05:01:45 -0400 | [diff] [blame] | 2516 | opened); |
Al Viro | d958527 | 2012-06-22 12:39:14 +0400 | [diff] [blame] | 2517 | if (error < 0) { |
Al Viro | d958527 | 2012-06-22 12:39:14 +0400 | [diff] [blame] | 2518 | if (create_error && error == -ENOENT) |
| 2519 | error = create_error; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2520 | goto out; |
| 2521 | } |
| 2522 | |
| 2523 | acc_mode = op->acc_mode; |
Al Viro | 4723768 | 2012-06-10 05:01:45 -0400 | [diff] [blame] | 2524 | if (*opened & FILE_CREATED) { |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2525 | fsnotify_create(dir, dentry); |
| 2526 | acc_mode = MAY_OPEN; |
| 2527 | } |
| 2528 | |
Al Viro | d958527 | 2012-06-22 12:39:14 +0400 | [diff] [blame] | 2529 | if (error) { /* returned 1, that is */ |
Al Viro | 30d9049 | 2012-06-22 12:40:19 +0400 | [diff] [blame] | 2530 | if (WARN_ON(file->f_path.dentry == DENTRY_NOT_SET)) { |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2531 | error = -EIO; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2532 | goto out; |
| 2533 | } |
Al Viro | 30d9049 | 2012-06-22 12:40:19 +0400 | [diff] [blame] | 2534 | if (file->f_path.dentry) { |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2535 | dput(dentry); |
Al Viro | 30d9049 | 2012-06-22 12:40:19 +0400 | [diff] [blame] | 2536 | dentry = file->f_path.dentry; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2537 | } |
Sage Weil | 62b2ce9 | 2012-08-15 13:30:12 -0700 | [diff] [blame] | 2538 | if (create_error && dentry->d_inode == NULL) { |
| 2539 | error = create_error; |
| 2540 | goto out; |
| 2541 | } |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2542 | goto looked_up; |
| 2543 | } |
| 2544 | |
| 2545 | /* |
| 2546 | * We didn't have the inode before the open, so check open permission |
| 2547 | * here. |
| 2548 | */ |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2549 | error = may_open(&file->f_path, acc_mode, open_flag); |
| 2550 | if (error) |
| 2551 | fput(file); |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2552 | |
| 2553 | out: |
| 2554 | dput(dentry); |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2555 | return error; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2556 | |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2557 | no_open: |
| 2558 | if (need_lookup) { |
Al Viro | 72bd866 | 2012-06-10 17:17:17 -0400 | [diff] [blame] | 2559 | dentry = lookup_real(dir, dentry, nd->flags); |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2560 | if (IS_ERR(dentry)) |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2561 | return PTR_ERR(dentry); |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2562 | |
| 2563 | if (create_error) { |
| 2564 | int open_flag = op->open_flag; |
| 2565 | |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2566 | error = create_error; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2567 | if ((open_flag & O_EXCL)) { |
| 2568 | if (!dentry->d_inode) |
| 2569 | goto out; |
| 2570 | } else if (!dentry->d_inode) { |
| 2571 | goto out; |
| 2572 | } else if ((open_flag & O_TRUNC) && |
| 2573 | S_ISREG(dentry->d_inode->i_mode)) { |
| 2574 | goto out; |
| 2575 | } |
| 2576 | /* will fail later, go on to get the right error */ |
| 2577 | } |
| 2578 | } |
| 2579 | looked_up: |
| 2580 | path->dentry = dentry; |
| 2581 | path->mnt = nd->path.mnt; |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2582 | return 1; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2583 | } |
| 2584 | |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2585 | /* |
David Howells | 1acf0af | 2012-06-14 16:13:46 +0100 | [diff] [blame] | 2586 | * Look up and maybe create and open the last component. |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2587 | * |
| 2588 | * Must be called with i_mutex held on parent. |
| 2589 | * |
David Howells | 1acf0af | 2012-06-14 16:13:46 +0100 | [diff] [blame] | 2590 | * Returns 0 if the file was successfully atomically created (if necessary) and |
| 2591 | * opened. In this case the file will be returned attached to @file. |
| 2592 | * |
| 2593 | * Returns 1 if the file was not completely opened at this time, though lookups |
| 2594 | * and creations will have been performed and the dentry returned in @path will |
| 2595 | * be positive upon return if O_CREAT was specified. If O_CREAT wasn't |
| 2596 | * specified then a negative dentry may be returned. |
| 2597 | * |
| 2598 | * An error code is returned otherwise. |
| 2599 | * |
| 2600 | * FILE_CREATE will be set in @*opened if the dentry was created and will be |
| 2601 | * cleared otherwise prior to returning. |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2602 | */ |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2603 | static int lookup_open(struct nameidata *nd, struct path *path, |
| 2604 | struct file *file, |
| 2605 | const struct open_flags *op, |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 2606 | bool got_write, int *opened) |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2607 | { |
| 2608 | struct dentry *dir = nd->path.dentry; |
Miklos Szeredi | 54ef487 | 2012-06-05 15:10:16 +0200 | [diff] [blame] | 2609 | struct inode *dir_inode = dir->d_inode; |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2610 | struct dentry *dentry; |
| 2611 | int error; |
Miklos Szeredi | 54ef487 | 2012-06-05 15:10:16 +0200 | [diff] [blame] | 2612 | bool need_lookup; |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2613 | |
Al Viro | 4723768 | 2012-06-10 05:01:45 -0400 | [diff] [blame] | 2614 | *opened &= ~FILE_CREATED; |
Al Viro | 201f956 | 2012-06-22 12:42:10 +0400 | [diff] [blame] | 2615 | dentry = lookup_dcache(&nd->last, dir, nd->flags, &need_lookup); |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2616 | if (IS_ERR(dentry)) |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2617 | return PTR_ERR(dentry); |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2618 | |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2619 | /* Cached positive dentry: will open in f_op->open */ |
| 2620 | if (!need_lookup && dentry->d_inode) |
| 2621 | goto out_no_open; |
| 2622 | |
| 2623 | if ((nd->flags & LOOKUP_OPEN) && dir_inode->i_op->atomic_open) { |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 2624 | return atomic_open(nd, dentry, path, file, op, got_write, |
Al Viro | 4723768 | 2012-06-10 05:01:45 -0400 | [diff] [blame] | 2625 | need_lookup, opened); |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2626 | } |
| 2627 | |
Miklos Szeredi | 54ef487 | 2012-06-05 15:10:16 +0200 | [diff] [blame] | 2628 | if (need_lookup) { |
| 2629 | BUG_ON(dentry->d_inode); |
| 2630 | |
Al Viro | 72bd866 | 2012-06-10 17:17:17 -0400 | [diff] [blame] | 2631 | dentry = lookup_real(dir_inode, dentry, nd->flags); |
Miklos Szeredi | 54ef487 | 2012-06-05 15:10:16 +0200 | [diff] [blame] | 2632 | if (IS_ERR(dentry)) |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2633 | return PTR_ERR(dentry); |
Miklos Szeredi | 54ef487 | 2012-06-05 15:10:16 +0200 | [diff] [blame] | 2634 | } |
| 2635 | |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2636 | /* Negative dentry, just create the file */ |
| 2637 | if (!dentry->d_inode && (op->open_flag & O_CREAT)) { |
| 2638 | umode_t mode = op->mode; |
| 2639 | if (!IS_POSIXACL(dir->d_inode)) |
| 2640 | mode &= ~current_umask(); |
| 2641 | /* |
| 2642 | * This write is needed to ensure that a |
| 2643 | * rw->ro transition does not occur between |
| 2644 | * the time when the file is created and when |
| 2645 | * a permanent write count is taken through |
Miklos Szeredi | 015c3bb | 2012-06-05 15:10:27 +0200 | [diff] [blame] | 2646 | * the 'struct file' in finish_open(). |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2647 | */ |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 2648 | if (!got_write) { |
| 2649 | error = -EROFS; |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2650 | goto out_dput; |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 2651 | } |
Al Viro | 4723768 | 2012-06-10 05:01:45 -0400 | [diff] [blame] | 2652 | *opened |= FILE_CREATED; |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2653 | error = security_path_mknod(&nd->path, dentry, mode, 0); |
| 2654 | if (error) |
| 2655 | goto out_dput; |
Al Viro | 312b63f | 2012-06-10 18:09:36 -0400 | [diff] [blame] | 2656 | error = vfs_create(dir->d_inode, dentry, mode, |
| 2657 | nd->flags & LOOKUP_EXCL); |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2658 | if (error) |
| 2659 | goto out_dput; |
| 2660 | } |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2661 | out_no_open: |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2662 | path->dentry = dentry; |
| 2663 | path->mnt = nd->path.mnt; |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2664 | return 1; |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2665 | |
| 2666 | out_dput: |
| 2667 | dput(dentry); |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2668 | return error; |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2669 | } |
| 2670 | |
| 2671 | /* |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 2672 | * Handle the last step of open() |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2673 | */ |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2674 | static int do_last(struct nameidata *nd, struct path *path, |
| 2675 | struct file *file, const struct open_flags *op, |
Jeff Layton | 669abf4 | 2012-10-10 16:43:10 -0400 | [diff] [blame] | 2676 | int *opened, struct filename *name) |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2677 | { |
Al Viro | a1e2803 | 2009-12-24 02:12:06 -0500 | [diff] [blame] | 2678 | struct dentry *dir = nd->path.dentry; |
Al Viro | ca344a89 | 2011-03-09 00:36:45 -0500 | [diff] [blame] | 2679 | int open_flag = op->open_flag; |
Miklos Szeredi | 77d660a | 2012-06-05 15:10:30 +0200 | [diff] [blame] | 2680 | bool will_truncate = (open_flag & O_TRUNC) != 0; |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 2681 | bool got_write = false; |
Al Viro | bcda765 | 2011-03-13 16:42:14 -0400 | [diff] [blame] | 2682 | int acc_mode = op->acc_mode; |
Miklos Szeredi | a1eb331 | 2012-05-21 17:30:07 +0200 | [diff] [blame] | 2683 | struct inode *inode; |
Miklos Szeredi | 77d660a | 2012-06-05 15:10:30 +0200 | [diff] [blame] | 2684 | bool symlink_ok = false; |
Miklos Szeredi | 16b1c1c | 2012-05-21 17:30:19 +0200 | [diff] [blame] | 2685 | struct path save_parent = { .dentry = NULL, .mnt = NULL }; |
| 2686 | bool retried = false; |
Al Viro | 16c2cd7 | 2011-02-22 15:50:10 -0500 | [diff] [blame] | 2687 | int error; |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2688 | |
Al Viro | c3e380b | 2011-02-23 13:39:45 -0500 | [diff] [blame] | 2689 | nd->flags &= ~LOOKUP_PARENT; |
| 2690 | nd->flags |= op->intent; |
| 2691 | |
Al Viro | bc77daa | 2013-06-06 09:12:33 -0400 | [diff] [blame] | 2692 | if (nd->last_type != LAST_NORM) { |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 2693 | error = handle_dots(nd, nd->last_type); |
| 2694 | if (error) |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2695 | return error; |
Miklos Szeredi | e83db16 | 2012-06-05 15:10:29 +0200 | [diff] [blame] | 2696 | goto finish_open; |
Al Viro | 1f36f77 | 2009-12-26 10:56:19 -0500 | [diff] [blame] | 2697 | } |
Al Viro | 67ee3ad | 2009-12-26 07:01:01 -0500 | [diff] [blame] | 2698 | |
Al Viro | ca344a89 | 2011-03-09 00:36:45 -0500 | [diff] [blame] | 2699 | if (!(open_flag & O_CREAT)) { |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 2700 | if (nd->last.name[nd->last.len]) |
| 2701 | nd->flags |= LOOKUP_FOLLOW | LOOKUP_DIRECTORY; |
Al Viro | bcda765 | 2011-03-13 16:42:14 -0400 | [diff] [blame] | 2702 | if (open_flag & O_PATH && !(nd->flags & LOOKUP_FOLLOW)) |
Miklos Szeredi | 77d660a | 2012-06-05 15:10:30 +0200 | [diff] [blame] | 2703 | symlink_ok = true; |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 2704 | /* we _can_ be in RCU mode here */ |
Al Viro | e97cdc8 | 2013-01-24 18:16:00 -0500 | [diff] [blame] | 2705 | error = lookup_fast(nd, path, &inode); |
Miklos Szeredi | 7157486 | 2012-06-05 15:10:14 +0200 | [diff] [blame] | 2706 | if (likely(!error)) |
| 2707 | goto finish_lookup; |
Miklos Szeredi | a1eb331 | 2012-05-21 17:30:07 +0200 | [diff] [blame] | 2708 | |
Miklos Szeredi | 7157486 | 2012-06-05 15:10:14 +0200 | [diff] [blame] | 2709 | if (error < 0) |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2710 | goto out; |
Miklos Szeredi | 37d7fff | 2012-06-05 15:10:12 +0200 | [diff] [blame] | 2711 | |
Miklos Szeredi | 7157486 | 2012-06-05 15:10:14 +0200 | [diff] [blame] | 2712 | BUG_ON(nd->inode != dir->d_inode); |
Miklos Szeredi | b6183df | 2012-06-05 15:10:13 +0200 | [diff] [blame] | 2713 | } else { |
| 2714 | /* create side of things */ |
| 2715 | /* |
| 2716 | * This will *only* deal with leaving RCU mode - LOOKUP_JUMPED |
| 2717 | * has been cleared when we got to the last component we are |
| 2718 | * about to look up |
| 2719 | */ |
| 2720 | error = complete_walk(nd); |
| 2721 | if (error) |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2722 | return error; |
Miklos Szeredi | b6183df | 2012-06-05 15:10:13 +0200 | [diff] [blame] | 2723 | |
Jeff Layton | 33e2208 | 2013-04-12 15:16:32 -0400 | [diff] [blame] | 2724 | audit_inode(name, dir, LOOKUP_PARENT); |
Miklos Szeredi | b6183df | 2012-06-05 15:10:13 +0200 | [diff] [blame] | 2725 | error = -EISDIR; |
| 2726 | /* trailing slashes? */ |
| 2727 | if (nd->last.name[nd->last.len]) |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2728 | goto out; |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 2729 | } |
| 2730 | |
Miklos Szeredi | 16b1c1c | 2012-05-21 17:30:19 +0200 | [diff] [blame] | 2731 | retry_lookup: |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 2732 | if (op->open_flag & (O_CREAT | O_TRUNC | O_WRONLY | O_RDWR)) { |
| 2733 | error = mnt_want_write(nd->path.mnt); |
| 2734 | if (!error) |
| 2735 | got_write = true; |
| 2736 | /* |
| 2737 | * do _not_ fail yet - we might not need that or fail with |
| 2738 | * a different error; let lookup_open() decide; we'll be |
| 2739 | * dropping this one anyway. |
| 2740 | */ |
| 2741 | } |
Al Viro | a1e2803 | 2009-12-24 02:12:06 -0500 | [diff] [blame] | 2742 | mutex_lock(&dir->d_inode->i_mutex); |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 2743 | error = lookup_open(nd, path, file, op, got_write, opened); |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2744 | mutex_unlock(&dir->d_inode->i_mutex); |
Al Viro | a1e2803 | 2009-12-24 02:12:06 -0500 | [diff] [blame] | 2745 | |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2746 | if (error <= 0) { |
| 2747 | if (error) |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2748 | goto out; |
| 2749 | |
Al Viro | 4723768 | 2012-06-10 05:01:45 -0400 | [diff] [blame] | 2750 | if ((*opened & FILE_CREATED) || |
Al Viro | 496ad9a | 2013-01-23 17:07:38 -0500 | [diff] [blame] | 2751 | !S_ISREG(file_inode(file)->i_mode)) |
Miklos Szeredi | 77d660a | 2012-06-05 15:10:30 +0200 | [diff] [blame] | 2752 | will_truncate = false; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2753 | |
Jeff Layton | adb5c24 | 2012-10-10 16:43:13 -0400 | [diff] [blame] | 2754 | audit_inode(name, file->f_path.dentry, 0); |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2755 | goto opened; |
| 2756 | } |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2757 | |
Al Viro | 4723768 | 2012-06-10 05:01:45 -0400 | [diff] [blame] | 2758 | if (*opened & FILE_CREATED) { |
Al Viro | 9b44f1b | 2011-03-09 00:17:27 -0500 | [diff] [blame] | 2759 | /* Don't check for write permission, don't truncate */ |
Al Viro | ca344a89 | 2011-03-09 00:36:45 -0500 | [diff] [blame] | 2760 | open_flag &= ~O_TRUNC; |
Miklos Szeredi | 77d660a | 2012-06-05 15:10:30 +0200 | [diff] [blame] | 2761 | will_truncate = false; |
Al Viro | bcda765 | 2011-03-13 16:42:14 -0400 | [diff] [blame] | 2762 | acc_mode = MAY_OPEN; |
Miklos Szeredi | d58ffd3 | 2012-06-05 15:10:15 +0200 | [diff] [blame] | 2763 | path_to_nameidata(path, nd); |
Miklos Szeredi | e83db16 | 2012-06-05 15:10:29 +0200 | [diff] [blame] | 2764 | goto finish_open_created; |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2765 | } |
| 2766 | |
| 2767 | /* |
Jeff Layton | 3134f37 | 2012-07-25 10:19:47 -0400 | [diff] [blame] | 2768 | * create/update audit record if it already exists. |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2769 | */ |
Jeff Layton | 3134f37 | 2012-07-25 10:19:47 -0400 | [diff] [blame] | 2770 | if (path->dentry->d_inode) |
Jeff Layton | adb5c24 | 2012-10-10 16:43:13 -0400 | [diff] [blame] | 2771 | audit_inode(name, path->dentry, 0); |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2772 | |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2773 | /* |
| 2774 | * If atomic_open() acquired write access it is dropped now due to |
| 2775 | * possible mount and symlink following (this might be optimized away if |
| 2776 | * necessary...) |
| 2777 | */ |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 2778 | if (got_write) { |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2779 | mnt_drop_write(nd->path.mnt); |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 2780 | got_write = false; |
Miklos Szeredi | d18e900 | 2012-06-05 15:10:17 +0200 | [diff] [blame] | 2781 | } |
| 2782 | |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2783 | error = -EEXIST; |
Al Viro | f8310c5 | 2012-07-30 11:50:30 +0400 | [diff] [blame] | 2784 | if ((open_flag & (O_EXCL | O_CREAT)) == (O_EXCL | O_CREAT)) |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2785 | goto exit_dput; |
| 2786 | |
David Howells | 9875cf8 | 2011-01-14 18:45:21 +0000 | [diff] [blame] | 2787 | error = follow_managed(path, nd->flags); |
| 2788 | if (error < 0) |
| 2789 | goto exit_dput; |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2790 | |
Al Viro | a3fbbde | 2011-11-07 21:21:26 +0000 | [diff] [blame] | 2791 | if (error) |
| 2792 | nd->flags |= LOOKUP_JUMPED; |
| 2793 | |
Miklos Szeredi | decf340 | 2012-05-21 17:30:08 +0200 | [diff] [blame] | 2794 | BUG_ON(nd->flags & LOOKUP_RCU); |
| 2795 | inode = path->dentry->d_inode; |
Miklos Szeredi | 5f5daac | 2012-05-21 17:30:14 +0200 | [diff] [blame] | 2796 | finish_lookup: |
| 2797 | /* we _can_ be in RCU mode here */ |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2798 | error = -ENOENT; |
Miklos Szeredi | 54c33e7 | 2012-05-21 17:30:10 +0200 | [diff] [blame] | 2799 | if (!inode) { |
| 2800 | path_to_nameidata(path, nd); |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2801 | goto out; |
Miklos Szeredi | 54c33e7 | 2012-05-21 17:30:10 +0200 | [diff] [blame] | 2802 | } |
Al Viro | 9e67f36 | 2009-12-26 07:04:50 -0500 | [diff] [blame] | 2803 | |
Miklos Szeredi | d45ea86 | 2012-05-21 17:30:09 +0200 | [diff] [blame] | 2804 | if (should_follow_link(inode, !symlink_ok)) { |
| 2805 | if (nd->flags & LOOKUP_RCU) { |
| 2806 | if (unlikely(unlazy_walk(nd, path->dentry))) { |
| 2807 | error = -ECHILD; |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2808 | goto out; |
Miklos Szeredi | d45ea86 | 2012-05-21 17:30:09 +0200 | [diff] [blame] | 2809 | } |
| 2810 | } |
| 2811 | BUG_ON(inode != path->dentry->d_inode); |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2812 | return 1; |
Miklos Szeredi | d45ea86 | 2012-05-21 17:30:09 +0200 | [diff] [blame] | 2813 | } |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2814 | |
Miklos Szeredi | 16b1c1c | 2012-05-21 17:30:19 +0200 | [diff] [blame] | 2815 | if ((nd->flags & LOOKUP_RCU) || nd->path.mnt != path->mnt) { |
| 2816 | path_to_nameidata(path, nd); |
| 2817 | } else { |
| 2818 | save_parent.dentry = nd->path.dentry; |
| 2819 | save_parent.mnt = mntget(path->mnt); |
| 2820 | nd->path.dentry = path->dentry; |
| 2821 | |
| 2822 | } |
Miklos Szeredi | decf340 | 2012-05-21 17:30:08 +0200 | [diff] [blame] | 2823 | nd->inode = inode; |
Al Viro | a3fbbde | 2011-11-07 21:21:26 +0000 | [diff] [blame] | 2824 | /* Why this, you ask? _Now_ we might have grown LOOKUP_JUMPED... */ |
Al Viro | bc77daa | 2013-06-06 09:12:33 -0400 | [diff] [blame] | 2825 | finish_open: |
Al Viro | a3fbbde | 2011-11-07 21:21:26 +0000 | [diff] [blame] | 2826 | error = complete_walk(nd); |
Miklos Szeredi | 16b1c1c | 2012-05-21 17:30:19 +0200 | [diff] [blame] | 2827 | if (error) { |
| 2828 | path_put(&save_parent); |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2829 | return error; |
Miklos Szeredi | 16b1c1c | 2012-05-21 17:30:19 +0200 | [diff] [blame] | 2830 | } |
Al Viro | bc77daa | 2013-06-06 09:12:33 -0400 | [diff] [blame] | 2831 | audit_inode(name, nd->path.dentry, 0); |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2832 | error = -EISDIR; |
Miklos Szeredi | 050ac84 | 2012-05-21 17:30:12 +0200 | [diff] [blame] | 2833 | if ((open_flag & O_CREAT) && S_ISDIR(nd->inode->i_mode)) |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2834 | goto out; |
Miklos Szeredi | af2f554 | 2012-05-21 17:30:11 +0200 | [diff] [blame] | 2835 | error = -ENOTDIR; |
Al Viro | 0525290 | 2013-06-06 19:33:47 -0400 | [diff] [blame] | 2836 | if ((nd->flags & LOOKUP_DIRECTORY) && !can_lookup(nd->inode)) |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2837 | goto out; |
Al Viro | 6c0d46c | 2011-03-09 00:59:59 -0500 | [diff] [blame] | 2838 | if (!S_ISREG(nd->inode->i_mode)) |
Miklos Szeredi | 77d660a | 2012-06-05 15:10:30 +0200 | [diff] [blame] | 2839 | will_truncate = false; |
Al Viro | 6c0d46c | 2011-03-09 00:59:59 -0500 | [diff] [blame] | 2840 | |
Al Viro | 0f9d1a1 | 2011-03-09 00:13:14 -0500 | [diff] [blame] | 2841 | if (will_truncate) { |
| 2842 | error = mnt_want_write(nd->path.mnt); |
| 2843 | if (error) |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2844 | goto out; |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 2845 | got_write = true; |
Al Viro | 0f9d1a1 | 2011-03-09 00:13:14 -0500 | [diff] [blame] | 2846 | } |
Miklos Szeredi | e83db16 | 2012-06-05 15:10:29 +0200 | [diff] [blame] | 2847 | finish_open_created: |
Al Viro | bcda765 | 2011-03-13 16:42:14 -0400 | [diff] [blame] | 2848 | error = may_open(&nd->path, acc_mode, open_flag); |
Al Viro | ca344a89 | 2011-03-09 00:36:45 -0500 | [diff] [blame] | 2849 | if (error) |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2850 | goto out; |
Al Viro | 30d9049 | 2012-06-22 12:40:19 +0400 | [diff] [blame] | 2851 | file->f_path.mnt = nd->path.mnt; |
| 2852 | error = finish_open(file, nd->path.dentry, NULL, opened); |
| 2853 | if (error) { |
Al Viro | 30d9049 | 2012-06-22 12:40:19 +0400 | [diff] [blame] | 2854 | if (error == -EOPENSTALE) |
Miklos Szeredi | f60dc3d | 2012-06-05 15:10:31 +0200 | [diff] [blame] | 2855 | goto stale_open; |
Miklos Szeredi | 015c3bb | 2012-06-05 15:10:27 +0200 | [diff] [blame] | 2856 | goto out; |
Miklos Szeredi | f60dc3d | 2012-06-05 15:10:31 +0200 | [diff] [blame] | 2857 | } |
Miklos Szeredi | a8277b9 | 2012-06-05 15:10:32 +0200 | [diff] [blame] | 2858 | opened: |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2859 | error = open_check_o_direct(file); |
Miklos Szeredi | 015c3bb | 2012-06-05 15:10:27 +0200 | [diff] [blame] | 2860 | if (error) |
| 2861 | goto exit_fput; |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2862 | error = ima_file_check(file, op->acc_mode); |
Miklos Szeredi | aa4caad | 2012-06-05 15:10:28 +0200 | [diff] [blame] | 2863 | if (error) |
| 2864 | goto exit_fput; |
| 2865 | |
| 2866 | if (will_truncate) { |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2867 | error = handle_truncate(file); |
Miklos Szeredi | aa4caad | 2012-06-05 15:10:28 +0200 | [diff] [blame] | 2868 | if (error) |
| 2869 | goto exit_fput; |
Al Viro | 0f9d1a1 | 2011-03-09 00:13:14 -0500 | [diff] [blame] | 2870 | } |
Al Viro | ca344a89 | 2011-03-09 00:36:45 -0500 | [diff] [blame] | 2871 | out: |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 2872 | if (got_write) |
Al Viro | 0f9d1a1 | 2011-03-09 00:13:14 -0500 | [diff] [blame] | 2873 | mnt_drop_write(nd->path.mnt); |
Miklos Szeredi | 16b1c1c | 2012-05-21 17:30:19 +0200 | [diff] [blame] | 2874 | path_put(&save_parent); |
Miklos Szeredi | e276ae6 | 2012-05-21 17:30:06 +0200 | [diff] [blame] | 2875 | terminate_walk(nd); |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2876 | return error; |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2877 | |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2878 | exit_dput: |
| 2879 | path_put_conditional(path, nd); |
Al Viro | ca344a89 | 2011-03-09 00:36:45 -0500 | [diff] [blame] | 2880 | goto out; |
Miklos Szeredi | 015c3bb | 2012-06-05 15:10:27 +0200 | [diff] [blame] | 2881 | exit_fput: |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2882 | fput(file); |
| 2883 | goto out; |
Miklos Szeredi | 015c3bb | 2012-06-05 15:10:27 +0200 | [diff] [blame] | 2884 | |
Miklos Szeredi | f60dc3d | 2012-06-05 15:10:31 +0200 | [diff] [blame] | 2885 | stale_open: |
| 2886 | /* If no saved parent or already retried then can't retry */ |
| 2887 | if (!save_parent.dentry || retried) |
| 2888 | goto out; |
| 2889 | |
| 2890 | BUG_ON(save_parent.dentry != dir); |
| 2891 | path_put(&nd->path); |
| 2892 | nd->path = save_parent; |
| 2893 | nd->inode = dir->d_inode; |
| 2894 | save_parent.mnt = NULL; |
| 2895 | save_parent.dentry = NULL; |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 2896 | if (got_write) { |
Miklos Szeredi | f60dc3d | 2012-06-05 15:10:31 +0200 | [diff] [blame] | 2897 | mnt_drop_write(nd->path.mnt); |
Al Viro | 64894cf | 2012-07-31 00:53:35 +0400 | [diff] [blame] | 2898 | got_write = false; |
Miklos Szeredi | f60dc3d | 2012-06-05 15:10:31 +0200 | [diff] [blame] | 2899 | } |
| 2900 | retried = true; |
| 2901 | goto retry_lookup; |
Al Viro | fb1cc55 | 2009-12-24 01:58:28 -0500 | [diff] [blame] | 2902 | } |
| 2903 | |
Al Viro | 60545d0 | 2013-06-07 01:20:27 -0400 | [diff] [blame] | 2904 | static int do_tmpfile(int dfd, struct filename *pathname, |
| 2905 | struct nameidata *nd, int flags, |
| 2906 | const struct open_flags *op, |
| 2907 | struct file *file, int *opened) |
| 2908 | { |
| 2909 | static const struct qstr name = QSTR_INIT("/", 1); |
| 2910 | struct dentry *dentry, *child; |
| 2911 | struct inode *dir; |
| 2912 | int error = path_lookupat(dfd, pathname->name, |
| 2913 | flags | LOOKUP_DIRECTORY, nd); |
| 2914 | if (unlikely(error)) |
| 2915 | return error; |
| 2916 | error = mnt_want_write(nd->path.mnt); |
| 2917 | if (unlikely(error)) |
| 2918 | goto out; |
| 2919 | /* we want directory to be writable */ |
| 2920 | error = inode_permission(nd->inode, MAY_WRITE | MAY_EXEC); |
| 2921 | if (error) |
| 2922 | goto out2; |
| 2923 | dentry = nd->path.dentry; |
| 2924 | dir = dentry->d_inode; |
| 2925 | if (!dir->i_op->tmpfile) { |
| 2926 | error = -EOPNOTSUPP; |
| 2927 | goto out2; |
| 2928 | } |
| 2929 | child = d_alloc(dentry, &name); |
| 2930 | if (unlikely(!child)) { |
| 2931 | error = -ENOMEM; |
| 2932 | goto out2; |
| 2933 | } |
| 2934 | nd->flags &= ~LOOKUP_DIRECTORY; |
| 2935 | nd->flags |= op->intent; |
| 2936 | dput(nd->path.dentry); |
| 2937 | nd->path.dentry = child; |
| 2938 | error = dir->i_op->tmpfile(dir, nd->path.dentry, op->mode); |
| 2939 | if (error) |
| 2940 | goto out2; |
| 2941 | audit_inode(pathname, nd->path.dentry, 0); |
| 2942 | error = may_open(&nd->path, op->acc_mode, op->open_flag); |
| 2943 | if (error) |
| 2944 | goto out2; |
| 2945 | file->f_path.mnt = nd->path.mnt; |
| 2946 | error = finish_open(file, nd->path.dentry, NULL, opened); |
| 2947 | if (error) |
| 2948 | goto out2; |
| 2949 | error = open_check_o_direct(file); |
Al Viro | f4e0c30 | 2013-06-11 08:34:36 +0400 | [diff] [blame] | 2950 | if (error) { |
Al Viro | 60545d0 | 2013-06-07 01:20:27 -0400 | [diff] [blame] | 2951 | fput(file); |
Al Viro | f4e0c30 | 2013-06-11 08:34:36 +0400 | [diff] [blame] | 2952 | } else if (!(op->open_flag & O_EXCL)) { |
| 2953 | struct inode *inode = file_inode(file); |
| 2954 | spin_lock(&inode->i_lock); |
| 2955 | inode->i_state |= I_LINKABLE; |
| 2956 | spin_unlock(&inode->i_lock); |
| 2957 | } |
Al Viro | 60545d0 | 2013-06-07 01:20:27 -0400 | [diff] [blame] | 2958 | out2: |
| 2959 | mnt_drop_write(nd->path.mnt); |
| 2960 | out: |
| 2961 | path_put(&nd->path); |
| 2962 | return error; |
| 2963 | } |
| 2964 | |
Jeff Layton | 669abf4 | 2012-10-10 16:43:10 -0400 | [diff] [blame] | 2965 | static struct file *path_openat(int dfd, struct filename *pathname, |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 2966 | struct nameidata *nd, const struct open_flags *op, int flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2967 | { |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 2968 | struct file *base = NULL; |
Al Viro | 30d9049 | 2012-06-22 12:40:19 +0400 | [diff] [blame] | 2969 | struct file *file; |
Al Viro | 9850c05 | 2010-01-13 15:01:15 -0500 | [diff] [blame] | 2970 | struct path path; |
Al Viro | 4723768 | 2012-06-10 05:01:45 -0400 | [diff] [blame] | 2971 | int opened = 0; |
Al Viro | 13aab42 | 2011-02-23 17:54:08 -0500 | [diff] [blame] | 2972 | int error; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2973 | |
Al Viro | 30d9049 | 2012-06-22 12:40:19 +0400 | [diff] [blame] | 2974 | file = get_empty_filp(); |
Al Viro | 1afc99b | 2013-02-14 20:41:04 -0500 | [diff] [blame] | 2975 | if (IS_ERR(file)) |
| 2976 | return file; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2977 | |
Al Viro | 30d9049 | 2012-06-22 12:40:19 +0400 | [diff] [blame] | 2978 | file->f_flags = op->open_flag; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2979 | |
Al Viro | bb458c6 | 2013-07-13 13:26:37 +0400 | [diff] [blame] | 2980 | if (unlikely(file->f_flags & __O_TMPFILE)) { |
Al Viro | 60545d0 | 2013-06-07 01:20:27 -0400 | [diff] [blame] | 2981 | error = do_tmpfile(dfd, pathname, nd, flags, op, file, &opened); |
| 2982 | goto out; |
| 2983 | } |
| 2984 | |
Jeff Layton | 669abf4 | 2012-10-10 16:43:10 -0400 | [diff] [blame] | 2985 | error = path_init(dfd, pathname->name, flags | LOOKUP_PARENT, nd, &base); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2986 | if (unlikely(error)) |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2987 | goto out; |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2988 | |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 2989 | current->total_link_count = 0; |
Jeff Layton | 669abf4 | 2012-10-10 16:43:10 -0400 | [diff] [blame] | 2990 | error = link_path_walk(pathname->name, nd); |
Nick Piggin | 31e6b01 | 2011-01-07 17:49:52 +1100 | [diff] [blame] | 2991 | if (unlikely(error)) |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2992 | goto out; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2993 | |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 2994 | error = do_last(nd, &path, file, op, &opened, pathname); |
| 2995 | while (unlikely(error > 0)) { /* trailing symlink */ |
Nick Piggin | 7b9337a | 2011-01-14 08:42:43 +0000 | [diff] [blame] | 2996 | struct path link = path; |
Al Viro | def4af3 | 2009-12-26 08:37:05 -0500 | [diff] [blame] | 2997 | void *cookie; |
Al Viro | 574197e | 2011-03-14 22:20:34 -0400 | [diff] [blame] | 2998 | if (!(nd->flags & LOOKUP_FOLLOW)) { |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 2999 | path_put_conditional(&path, nd); |
| 3000 | path_put(&nd->path); |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 3001 | error = -ELOOP; |
Al Viro | 40b3913 | 2011-03-09 16:22:18 -0500 | [diff] [blame] | 3002 | break; |
| 3003 | } |
Kees Cook | 800179c | 2012-07-25 17:29:07 -0700 | [diff] [blame] | 3004 | error = may_follow_link(&link, nd); |
| 3005 | if (unlikely(error)) |
| 3006 | break; |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 3007 | nd->flags |= LOOKUP_PARENT; |
| 3008 | nd->flags &= ~(LOOKUP_OPEN|LOOKUP_CREATE|LOOKUP_EXCL); |
Al Viro | 574197e | 2011-03-14 22:20:34 -0400 | [diff] [blame] | 3009 | error = follow_link(&link, nd, &cookie); |
Al Viro | c3e380b | 2011-02-23 13:39:45 -0500 | [diff] [blame] | 3010 | if (unlikely(error)) |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 3011 | break; |
| 3012 | error = do_last(nd, &path, file, op, &opened, pathname); |
Al Viro | 574197e | 2011-03-14 22:20:34 -0400 | [diff] [blame] | 3013 | put_link(nd, &link, cookie); |
Al Viro | 806b681 | 2009-12-26 07:16:40 -0500 | [diff] [blame] | 3014 | } |
Al Viro | 10fa8e6 | 2009-12-26 07:09:49 -0500 | [diff] [blame] | 3015 | out: |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 3016 | if (nd->root.mnt && !(nd->flags & LOOKUP_ROOT)) |
| 3017 | path_put(&nd->root); |
Al Viro | fe2d35f | 2011-03-05 22:58:25 -0500 | [diff] [blame] | 3018 | if (base) |
| 3019 | fput(base); |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 3020 | if (!(opened & FILE_OPENED)) { |
| 3021 | BUG_ON(!error); |
Al Viro | 30d9049 | 2012-06-22 12:40:19 +0400 | [diff] [blame] | 3022 | put_filp(file); |
Miklos Szeredi | 015c3bb | 2012-06-05 15:10:27 +0200 | [diff] [blame] | 3023 | } |
Al Viro | 2675a4e | 2012-06-22 12:41:10 +0400 | [diff] [blame] | 3024 | if (unlikely(error)) { |
| 3025 | if (error == -EOPENSTALE) { |
| 3026 | if (flags & LOOKUP_RCU) |
| 3027 | error = -ECHILD; |
| 3028 | else |
| 3029 | error = -ESTALE; |
| 3030 | } |
| 3031 | file = ERR_PTR(error); |
| 3032 | } |
| 3033 | return file; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3034 | } |
| 3035 | |
Jeff Layton | 669abf4 | 2012-10-10 16:43:10 -0400 | [diff] [blame] | 3036 | struct file *do_filp_open(int dfd, struct filename *pathname, |
Al Viro | f9652e1 | 2013-06-11 08:23:01 +0400 | [diff] [blame] | 3037 | const struct open_flags *op) |
Al Viro | 13aab42 | 2011-02-23 17:54:08 -0500 | [diff] [blame] | 3038 | { |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 3039 | struct nameidata nd; |
Al Viro | f9652e1 | 2013-06-11 08:23:01 +0400 | [diff] [blame] | 3040 | int flags = op->lookup_flags; |
Al Viro | 13aab42 | 2011-02-23 17:54:08 -0500 | [diff] [blame] | 3041 | struct file *filp; |
| 3042 | |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 3043 | filp = path_openat(dfd, pathname, &nd, op, flags | LOOKUP_RCU); |
Al Viro | 13aab42 | 2011-02-23 17:54:08 -0500 | [diff] [blame] | 3044 | if (unlikely(filp == ERR_PTR(-ECHILD))) |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 3045 | filp = path_openat(dfd, pathname, &nd, op, flags); |
Al Viro | 13aab42 | 2011-02-23 17:54:08 -0500 | [diff] [blame] | 3046 | if (unlikely(filp == ERR_PTR(-ESTALE))) |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 3047 | filp = path_openat(dfd, pathname, &nd, op, flags | LOOKUP_REVAL); |
Al Viro | 13aab42 | 2011-02-23 17:54:08 -0500 | [diff] [blame] | 3048 | return filp; |
| 3049 | } |
| 3050 | |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 3051 | struct file *do_file_open_root(struct dentry *dentry, struct vfsmount *mnt, |
Al Viro | f9652e1 | 2013-06-11 08:23:01 +0400 | [diff] [blame] | 3052 | const char *name, const struct open_flags *op) |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 3053 | { |
| 3054 | struct nameidata nd; |
| 3055 | struct file *file; |
Jeff Layton | 669abf4 | 2012-10-10 16:43:10 -0400 | [diff] [blame] | 3056 | struct filename filename = { .name = name }; |
Al Viro | f9652e1 | 2013-06-11 08:23:01 +0400 | [diff] [blame] | 3057 | int flags = op->lookup_flags | LOOKUP_ROOT; |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 3058 | |
| 3059 | nd.root.mnt = mnt; |
| 3060 | nd.root.dentry = dentry; |
| 3061 | |
Al Viro | bcda765 | 2011-03-13 16:42:14 -0400 | [diff] [blame] | 3062 | if (dentry->d_inode->i_op->follow_link && op->intent & LOOKUP_OPEN) |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 3063 | return ERR_PTR(-ELOOP); |
| 3064 | |
Jeff Layton | 669abf4 | 2012-10-10 16:43:10 -0400 | [diff] [blame] | 3065 | file = path_openat(-1, &filename, &nd, op, flags | LOOKUP_RCU); |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 3066 | if (unlikely(file == ERR_PTR(-ECHILD))) |
Jeff Layton | 669abf4 | 2012-10-10 16:43:10 -0400 | [diff] [blame] | 3067 | file = path_openat(-1, &filename, &nd, op, flags); |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 3068 | if (unlikely(file == ERR_PTR(-ESTALE))) |
Jeff Layton | 669abf4 | 2012-10-10 16:43:10 -0400 | [diff] [blame] | 3069 | file = path_openat(-1, &filename, &nd, op, flags | LOOKUP_REVAL); |
Al Viro | 73d049a | 2011-03-11 12:08:24 -0500 | [diff] [blame] | 3070 | return file; |
| 3071 | } |
| 3072 | |
Jeff Layton | 1ac12b4 | 2012-12-11 12:10:06 -0500 | [diff] [blame] | 3073 | struct dentry *kern_path_create(int dfd, const char *pathname, |
| 3074 | struct path *path, unsigned int lookup_flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3075 | { |
Christoph Hellwig | c663e5d | 2005-06-23 00:09:49 -0700 | [diff] [blame] | 3076 | struct dentry *dentry = ERR_PTR(-EEXIST); |
Al Viro | ed75e95 | 2011-06-27 16:53:43 -0400 | [diff] [blame] | 3077 | struct nameidata nd; |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 3078 | int err2; |
Jeff Layton | 1ac12b4 | 2012-12-11 12:10:06 -0500 | [diff] [blame] | 3079 | int error; |
| 3080 | bool is_dir = (lookup_flags & LOOKUP_DIRECTORY); |
| 3081 | |
| 3082 | /* |
| 3083 | * Note that only LOOKUP_REVAL and LOOKUP_DIRECTORY matter here. Any |
| 3084 | * other flags passed in are ignored! |
| 3085 | */ |
| 3086 | lookup_flags &= LOOKUP_REVAL; |
| 3087 | |
| 3088 | error = do_path_lookup(dfd, pathname, LOOKUP_PARENT|lookup_flags, &nd); |
Al Viro | ed75e95 | 2011-06-27 16:53:43 -0400 | [diff] [blame] | 3089 | if (error) |
| 3090 | return ERR_PTR(error); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3091 | |
Christoph Hellwig | c663e5d | 2005-06-23 00:09:49 -0700 | [diff] [blame] | 3092 | /* |
| 3093 | * Yucky last component or no last component at all? |
| 3094 | * (foo/., foo/.., /////) |
| 3095 | */ |
Al Viro | ed75e95 | 2011-06-27 16:53:43 -0400 | [diff] [blame] | 3096 | if (nd.last_type != LAST_NORM) |
| 3097 | goto out; |
| 3098 | nd.flags &= ~LOOKUP_PARENT; |
| 3099 | nd.flags |= LOOKUP_CREATE | LOOKUP_EXCL; |
Christoph Hellwig | c663e5d | 2005-06-23 00:09:49 -0700 | [diff] [blame] | 3100 | |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 3101 | /* don't fail immediately if it's r/o, at least try to report other errors */ |
| 3102 | err2 = mnt_want_write(nd.path.mnt); |
Christoph Hellwig | c663e5d | 2005-06-23 00:09:49 -0700 | [diff] [blame] | 3103 | /* |
| 3104 | * Do the final lookup. |
| 3105 | */ |
Al Viro | ed75e95 | 2011-06-27 16:53:43 -0400 | [diff] [blame] | 3106 | mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); |
| 3107 | dentry = lookup_hash(&nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3108 | if (IS_ERR(dentry)) |
Al Viro | a8104a9 | 2012-07-20 02:25:00 +0400 | [diff] [blame] | 3109 | goto unlock; |
Christoph Hellwig | c663e5d | 2005-06-23 00:09:49 -0700 | [diff] [blame] | 3110 | |
Al Viro | a8104a9 | 2012-07-20 02:25:00 +0400 | [diff] [blame] | 3111 | error = -EEXIST; |
Al Viro | e9baf6e | 2008-05-15 04:49:12 -0400 | [diff] [blame] | 3112 | if (dentry->d_inode) |
Al Viro | a8104a9 | 2012-07-20 02:25:00 +0400 | [diff] [blame] | 3113 | goto fail; |
Christoph Hellwig | c663e5d | 2005-06-23 00:09:49 -0700 | [diff] [blame] | 3114 | /* |
| 3115 | * Special case - lookup gave negative, but... we had foo/bar/ |
| 3116 | * From the vfs_mknod() POV we just have a negative dentry - |
| 3117 | * all is fine. Let's be bastards - you had / on the end, you've |
| 3118 | * been asking for (non-existent) directory. -ENOENT for you. |
| 3119 | */ |
Al Viro | ed75e95 | 2011-06-27 16:53:43 -0400 | [diff] [blame] | 3120 | if (unlikely(!is_dir && nd.last.name[nd.last.len])) { |
Al Viro | a8104a9 | 2012-07-20 02:25:00 +0400 | [diff] [blame] | 3121 | error = -ENOENT; |
Al Viro | ed75e95 | 2011-06-27 16:53:43 -0400 | [diff] [blame] | 3122 | goto fail; |
Al Viro | e9baf6e | 2008-05-15 04:49:12 -0400 | [diff] [blame] | 3123 | } |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 3124 | if (unlikely(err2)) { |
| 3125 | error = err2; |
Al Viro | a8104a9 | 2012-07-20 02:25:00 +0400 | [diff] [blame] | 3126 | goto fail; |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 3127 | } |
Al Viro | ed75e95 | 2011-06-27 16:53:43 -0400 | [diff] [blame] | 3128 | *path = nd.path; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3129 | return dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3130 | fail: |
Al Viro | a8104a9 | 2012-07-20 02:25:00 +0400 | [diff] [blame] | 3131 | dput(dentry); |
| 3132 | dentry = ERR_PTR(error); |
| 3133 | unlock: |
Al Viro | ed75e95 | 2011-06-27 16:53:43 -0400 | [diff] [blame] | 3134 | mutex_unlock(&nd.path.dentry->d_inode->i_mutex); |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 3135 | if (!err2) |
| 3136 | mnt_drop_write(nd.path.mnt); |
Al Viro | ed75e95 | 2011-06-27 16:53:43 -0400 | [diff] [blame] | 3137 | out: |
| 3138 | path_put(&nd.path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3139 | return dentry; |
| 3140 | } |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3141 | EXPORT_SYMBOL(kern_path_create); |
| 3142 | |
Al Viro | 921a165 | 2012-07-20 01:15:31 +0400 | [diff] [blame] | 3143 | void done_path_create(struct path *path, struct dentry *dentry) |
| 3144 | { |
| 3145 | dput(dentry); |
| 3146 | mutex_unlock(&path->dentry->d_inode->i_mutex); |
Al Viro | a8104a9 | 2012-07-20 02:25:00 +0400 | [diff] [blame] | 3147 | mnt_drop_write(path->mnt); |
Al Viro | 921a165 | 2012-07-20 01:15:31 +0400 | [diff] [blame] | 3148 | path_put(path); |
| 3149 | } |
| 3150 | EXPORT_SYMBOL(done_path_create); |
| 3151 | |
Jeff Layton | 1ac12b4 | 2012-12-11 12:10:06 -0500 | [diff] [blame] | 3152 | struct dentry *user_path_create(int dfd, const char __user *pathname, |
| 3153 | struct path *path, unsigned int lookup_flags) |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3154 | { |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 3155 | struct filename *tmp = getname(pathname); |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3156 | struct dentry *res; |
| 3157 | if (IS_ERR(tmp)) |
| 3158 | return ERR_CAST(tmp); |
Jeff Layton | 1ac12b4 | 2012-12-11 12:10:06 -0500 | [diff] [blame] | 3159 | res = kern_path_create(dfd, tmp->name, path, lookup_flags); |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3160 | putname(tmp); |
| 3161 | return res; |
| 3162 | } |
| 3163 | EXPORT_SYMBOL(user_path_create); |
| 3164 | |
Al Viro | 1a67aaf | 2011-07-26 01:52:52 -0400 | [diff] [blame] | 3165 | 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] | 3166 | { |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 3167 | int error = may_create(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3168 | |
| 3169 | if (error) |
| 3170 | return error; |
| 3171 | |
Eric W. Biederman | 975d6b3 | 2011-11-13 12:16:43 -0800 | [diff] [blame] | 3172 | if ((S_ISCHR(mode) || S_ISBLK(mode)) && !capable(CAP_MKNOD)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3173 | return -EPERM; |
| 3174 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 3175 | if (!dir->i_op->mknod) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3176 | return -EPERM; |
| 3177 | |
Serge E. Hallyn | 08ce5f1 | 2008-04-29 01:00:10 -0700 | [diff] [blame] | 3178 | error = devcgroup_inode_mknod(mode, dev); |
| 3179 | if (error) |
| 3180 | return error; |
| 3181 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3182 | error = security_inode_mknod(dir, dentry, mode, dev); |
| 3183 | if (error) |
| 3184 | return error; |
| 3185 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3186 | error = dir->i_op->mknod(dir, dentry, mode, dev); |
Stephen Smalley | a74574a | 2005-09-09 13:01:44 -0700 | [diff] [blame] | 3187 | if (!error) |
Amy Griffis | f38aa94 | 2005-11-03 15:57:06 +0000 | [diff] [blame] | 3188 | fsnotify_create(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3189 | return error; |
| 3190 | } |
| 3191 | |
Al Viro | f69aac0 | 2011-07-26 04:31:40 -0400 | [diff] [blame] | 3192 | static int may_mknod(umode_t mode) |
Dave Hansen | 463c319 | 2008-02-15 14:37:57 -0800 | [diff] [blame] | 3193 | { |
| 3194 | switch (mode & S_IFMT) { |
| 3195 | case S_IFREG: |
| 3196 | case S_IFCHR: |
| 3197 | case S_IFBLK: |
| 3198 | case S_IFIFO: |
| 3199 | case S_IFSOCK: |
| 3200 | case 0: /* zero mode translates to S_IFREG */ |
| 3201 | return 0; |
| 3202 | case S_IFDIR: |
| 3203 | return -EPERM; |
| 3204 | default: |
| 3205 | return -EINVAL; |
| 3206 | } |
| 3207 | } |
| 3208 | |
Al Viro | 8208a22 | 2011-07-25 17:32:17 -0400 | [diff] [blame] | 3209 | SYSCALL_DEFINE4(mknodat, int, dfd, const char __user *, filename, umode_t, mode, |
Heiko Carstens | 2e4d092 | 2009-01-14 14:14:31 +0100 | [diff] [blame] | 3210 | unsigned, dev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3211 | { |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 3212 | struct dentry *dentry; |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3213 | struct path path; |
| 3214 | int error; |
Jeff Layton | 972567f | 2012-12-20 16:00:10 -0500 | [diff] [blame] | 3215 | unsigned int lookup_flags = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3216 | |
Al Viro | 8e4bfca | 2012-07-20 01:17:26 +0400 | [diff] [blame] | 3217 | error = may_mknod(mode); |
| 3218 | if (error) |
| 3219 | return error; |
Jeff Layton | 972567f | 2012-12-20 16:00:10 -0500 | [diff] [blame] | 3220 | retry: |
| 3221 | dentry = user_path_create(dfd, filename, &path, lookup_flags); |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3222 | if (IS_ERR(dentry)) |
| 3223 | return PTR_ERR(dentry); |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 3224 | |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3225 | if (!IS_POSIXACL(path.dentry->d_inode)) |
Al Viro | ce3b0f8 | 2009-03-29 19:08:22 -0400 | [diff] [blame] | 3226 | mode &= ~current_umask(); |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3227 | error = security_path_mknod(&path, dentry, mode, dev); |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 3228 | if (error) |
Al Viro | a8104a9 | 2012-07-20 02:25:00 +0400 | [diff] [blame] | 3229 | goto out; |
Dave Hansen | 463c319 | 2008-02-15 14:37:57 -0800 | [diff] [blame] | 3230 | switch (mode & S_IFMT) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3231 | case 0: case S_IFREG: |
Al Viro | 312b63f | 2012-06-10 18:09:36 -0400 | [diff] [blame] | 3232 | error = vfs_create(path.dentry->d_inode,dentry,mode,true); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3233 | break; |
| 3234 | case S_IFCHR: case S_IFBLK: |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3235 | error = vfs_mknod(path.dentry->d_inode,dentry,mode, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3236 | new_decode_dev(dev)); |
| 3237 | break; |
| 3238 | case S_IFIFO: case S_IFSOCK: |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3239 | error = vfs_mknod(path.dentry->d_inode,dentry,mode,0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3240 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3241 | } |
Al Viro | a8104a9 | 2012-07-20 02:25:00 +0400 | [diff] [blame] | 3242 | out: |
Al Viro | 921a165 | 2012-07-20 01:15:31 +0400 | [diff] [blame] | 3243 | done_path_create(&path, dentry); |
Jeff Layton | 972567f | 2012-12-20 16:00:10 -0500 | [diff] [blame] | 3244 | if (retry_estale(error, lookup_flags)) { |
| 3245 | lookup_flags |= LOOKUP_REVAL; |
| 3246 | goto retry; |
| 3247 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3248 | return error; |
| 3249 | } |
| 3250 | |
Al Viro | 8208a22 | 2011-07-25 17:32:17 -0400 | [diff] [blame] | 3251 | SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, dev) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 3252 | { |
| 3253 | return sys_mknodat(AT_FDCWD, filename, mode, dev); |
| 3254 | } |
| 3255 | |
Al Viro | 18bb1db | 2011-07-26 01:41:39 -0400 | [diff] [blame] | 3256 | int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3257 | { |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 3258 | int error = may_create(dir, dentry); |
Al Viro | 8de5277 | 2012-02-06 12:45:27 -0500 | [diff] [blame] | 3259 | unsigned max_links = dir->i_sb->s_max_links; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3260 | |
| 3261 | if (error) |
| 3262 | return error; |
| 3263 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 3264 | if (!dir->i_op->mkdir) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3265 | return -EPERM; |
| 3266 | |
| 3267 | mode &= (S_IRWXUGO|S_ISVTX); |
| 3268 | error = security_inode_mkdir(dir, dentry, mode); |
| 3269 | if (error) |
| 3270 | return error; |
| 3271 | |
Al Viro | 8de5277 | 2012-02-06 12:45:27 -0500 | [diff] [blame] | 3272 | if (max_links && dir->i_nlink >= max_links) |
| 3273 | return -EMLINK; |
| 3274 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3275 | error = dir->i_op->mkdir(dir, dentry, mode); |
Stephen Smalley | a74574a | 2005-09-09 13:01:44 -0700 | [diff] [blame] | 3276 | if (!error) |
Amy Griffis | f38aa94 | 2005-11-03 15:57:06 +0000 | [diff] [blame] | 3277 | fsnotify_mkdir(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3278 | return error; |
| 3279 | } |
| 3280 | |
Al Viro | a218d0f | 2011-11-21 14:59:34 -0500 | [diff] [blame] | 3281 | SYSCALL_DEFINE3(mkdirat, int, dfd, const char __user *, pathname, umode_t, mode) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3282 | { |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 3283 | struct dentry *dentry; |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3284 | struct path path; |
| 3285 | int error; |
Jeff Layton | b76d8b8 | 2012-12-20 16:04:09 -0500 | [diff] [blame] | 3286 | unsigned int lookup_flags = LOOKUP_DIRECTORY; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3287 | |
Jeff Layton | b76d8b8 | 2012-12-20 16:04:09 -0500 | [diff] [blame] | 3288 | retry: |
| 3289 | dentry = user_path_create(dfd, pathname, &path, lookup_flags); |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 3290 | if (IS_ERR(dentry)) |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3291 | return PTR_ERR(dentry); |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 3292 | |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3293 | if (!IS_POSIXACL(path.dentry->d_inode)) |
Al Viro | ce3b0f8 | 2009-03-29 19:08:22 -0400 | [diff] [blame] | 3294 | mode &= ~current_umask(); |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3295 | error = security_path_mkdir(&path, dentry, mode); |
Al Viro | a8104a9 | 2012-07-20 02:25:00 +0400 | [diff] [blame] | 3296 | if (!error) |
| 3297 | error = vfs_mkdir(path.dentry->d_inode, dentry, mode); |
Al Viro | 921a165 | 2012-07-20 01:15:31 +0400 | [diff] [blame] | 3298 | done_path_create(&path, dentry); |
Jeff Layton | b76d8b8 | 2012-12-20 16:04:09 -0500 | [diff] [blame] | 3299 | if (retry_estale(error, lookup_flags)) { |
| 3300 | lookup_flags |= LOOKUP_REVAL; |
| 3301 | goto retry; |
| 3302 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3303 | return error; |
| 3304 | } |
| 3305 | |
Al Viro | a218d0f | 2011-11-21 14:59:34 -0500 | [diff] [blame] | 3306 | SYSCALL_DEFINE2(mkdir, const char __user *, pathname, umode_t, mode) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 3307 | { |
| 3308 | return sys_mkdirat(AT_FDCWD, pathname, mode); |
| 3309 | } |
| 3310 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3311 | /* |
Sage Weil | a71905f | 2011-05-24 13:06:08 -0700 | [diff] [blame] | 3312 | * 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] | 3313 | * 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] | 3314 | * dentry, and if that is true (possibly after pruning the dcache), |
| 3315 | * then we drop the dentry now. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3316 | * |
| 3317 | * A low-level filesystem can, if it choses, legally |
| 3318 | * do a |
| 3319 | * |
| 3320 | * if (!d_unhashed(dentry)) |
| 3321 | * return -EBUSY; |
| 3322 | * |
| 3323 | * if it cannot handle the case of removing a directory |
| 3324 | * that is still in use by something else.. |
| 3325 | */ |
| 3326 | void dentry_unhash(struct dentry *dentry) |
| 3327 | { |
Vasily Averin | dc16842 | 2006-12-06 20:37:07 -0800 | [diff] [blame] | 3328 | shrink_dcache_parent(dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3329 | spin_lock(&dentry->d_lock); |
Sage Weil | 64252c7 | 2011-05-24 13:06:05 -0700 | [diff] [blame] | 3330 | if (dentry->d_count == 1) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3331 | __d_drop(dentry); |
| 3332 | spin_unlock(&dentry->d_lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3333 | } |
| 3334 | |
| 3335 | int vfs_rmdir(struct inode *dir, struct dentry *dentry) |
| 3336 | { |
| 3337 | int error = may_delete(dir, dentry, 1); |
| 3338 | |
| 3339 | if (error) |
| 3340 | return error; |
| 3341 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 3342 | if (!dir->i_op->rmdir) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3343 | return -EPERM; |
| 3344 | |
Al Viro | 1d2ef59 | 2011-09-14 18:55:41 +0100 | [diff] [blame] | 3345 | dget(dentry); |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 3346 | mutex_lock(&dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3347 | |
Sage Weil | 912dbc1 | 2011-05-24 13:06:11 -0700 | [diff] [blame] | 3348 | error = -EBUSY; |
| 3349 | if (d_mountpoint(dentry)) |
| 3350 | goto out; |
| 3351 | |
| 3352 | error = security_inode_rmdir(dir, dentry); |
| 3353 | if (error) |
| 3354 | goto out; |
| 3355 | |
Sage Weil | 3cebde2 | 2011-05-29 21:20:59 -0700 | [diff] [blame] | 3356 | shrink_dcache_parent(dentry); |
Sage Weil | 912dbc1 | 2011-05-24 13:06:11 -0700 | [diff] [blame] | 3357 | error = dir->i_op->rmdir(dir, dentry); |
| 3358 | if (error) |
| 3359 | goto out; |
| 3360 | |
| 3361 | dentry->d_inode->i_flags |= S_DEAD; |
| 3362 | dont_mount(dentry); |
| 3363 | |
| 3364 | out: |
| 3365 | mutex_unlock(&dentry->d_inode->i_mutex); |
Al Viro | 1d2ef59 | 2011-09-14 18:55:41 +0100 | [diff] [blame] | 3366 | dput(dentry); |
Sage Weil | 912dbc1 | 2011-05-24 13:06:11 -0700 | [diff] [blame] | 3367 | if (!error) |
| 3368 | d_delete(dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3369 | return error; |
| 3370 | } |
| 3371 | |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 3372 | static long do_rmdir(int dfd, const char __user *pathname) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3373 | { |
| 3374 | int error = 0; |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 3375 | struct filename *name; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3376 | struct dentry *dentry; |
| 3377 | struct nameidata nd; |
Jeff Layton | c6ee920 | 2012-12-20 16:28:33 -0500 | [diff] [blame] | 3378 | unsigned int lookup_flags = 0; |
| 3379 | retry: |
| 3380 | name = user_path_parent(dfd, pathname, &nd, lookup_flags); |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 3381 | if (IS_ERR(name)) |
| 3382 | return PTR_ERR(name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3383 | |
| 3384 | switch(nd.last_type) { |
OGAWA Hirofumi | 0612d9f | 2008-10-16 07:50:29 +0900 | [diff] [blame] | 3385 | case LAST_DOTDOT: |
| 3386 | error = -ENOTEMPTY; |
| 3387 | goto exit1; |
| 3388 | case LAST_DOT: |
| 3389 | error = -EINVAL; |
| 3390 | goto exit1; |
| 3391 | case LAST_ROOT: |
| 3392 | error = -EBUSY; |
| 3393 | goto exit1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3394 | } |
OGAWA Hirofumi | 0612d9f | 2008-10-16 07:50:29 +0900 | [diff] [blame] | 3395 | |
| 3396 | nd.flags &= ~LOOKUP_PARENT; |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 3397 | error = mnt_want_write(nd.path.mnt); |
| 3398 | if (error) |
| 3399 | goto exit1; |
OGAWA Hirofumi | 0612d9f | 2008-10-16 07:50:29 +0900 | [diff] [blame] | 3400 | |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 3401 | mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); |
Christoph Hellwig | 49705b7 | 2005-11-08 21:35:06 -0800 | [diff] [blame] | 3402 | dentry = lookup_hash(&nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3403 | error = PTR_ERR(dentry); |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 3404 | if (IS_ERR(dentry)) |
| 3405 | goto exit2; |
Theodore Ts'o | e6bc45d | 2011-06-06 19:19:40 -0400 | [diff] [blame] | 3406 | if (!dentry->d_inode) { |
| 3407 | error = -ENOENT; |
| 3408 | goto exit3; |
| 3409 | } |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 3410 | error = security_path_rmdir(&nd.path, dentry); |
| 3411 | if (error) |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 3412 | goto exit3; |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 3413 | error = vfs_rmdir(nd.path.dentry->d_inode, dentry); |
Dave Hansen | 0622753 | 2008-02-15 14:37:34 -0800 | [diff] [blame] | 3414 | exit3: |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 3415 | dput(dentry); |
| 3416 | exit2: |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 3417 | mutex_unlock(&nd.path.dentry->d_inode->i_mutex); |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 3418 | mnt_drop_write(nd.path.mnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3419 | exit1: |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 3420 | path_put(&nd.path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3421 | putname(name); |
Jeff Layton | c6ee920 | 2012-12-20 16:28:33 -0500 | [diff] [blame] | 3422 | if (retry_estale(error, lookup_flags)) { |
| 3423 | lookup_flags |= LOOKUP_REVAL; |
| 3424 | goto retry; |
| 3425 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3426 | return error; |
| 3427 | } |
| 3428 | |
Heiko Carstens | 3cdad42 | 2009-01-14 14:14:22 +0100 | [diff] [blame] | 3429 | SYSCALL_DEFINE1(rmdir, const char __user *, pathname) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 3430 | { |
| 3431 | return do_rmdir(AT_FDCWD, pathname); |
| 3432 | } |
| 3433 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3434 | int vfs_unlink(struct inode *dir, struct dentry *dentry) |
| 3435 | { |
| 3436 | int error = may_delete(dir, dentry, 0); |
| 3437 | |
| 3438 | if (error) |
| 3439 | return error; |
| 3440 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 3441 | if (!dir->i_op->unlink) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3442 | return -EPERM; |
| 3443 | |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 3444 | mutex_lock(&dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3445 | if (d_mountpoint(dentry)) |
| 3446 | error = -EBUSY; |
| 3447 | else { |
| 3448 | error = security_inode_unlink(dir, dentry); |
Al Viro | bec1052 | 2010-03-03 14:12:08 -0500 | [diff] [blame] | 3449 | if (!error) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3450 | error = dir->i_op->unlink(dir, dentry); |
Al Viro | bec1052 | 2010-03-03 14:12:08 -0500 | [diff] [blame] | 3451 | if (!error) |
Al Viro | d83c49f | 2010-04-30 17:17:09 -0400 | [diff] [blame] | 3452 | dont_mount(dentry); |
Al Viro | bec1052 | 2010-03-03 14:12:08 -0500 | [diff] [blame] | 3453 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3454 | } |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 3455 | mutex_unlock(&dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3456 | |
| 3457 | /* We don't d_delete() NFS sillyrenamed files--they still exist. */ |
| 3458 | if (!error && !(dentry->d_flags & DCACHE_NFSFS_RENAMED)) { |
Jan Kara | ece9591 | 2008-02-06 01:37:13 -0800 | [diff] [blame] | 3459 | fsnotify_link_count(dentry->d_inode); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3460 | d_delete(dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3461 | } |
Robert Love | 0eeca28 | 2005-07-12 17:06:03 -0400 | [diff] [blame] | 3462 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3463 | return error; |
| 3464 | } |
| 3465 | |
| 3466 | /* |
| 3467 | * 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] | 3468 | * 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] | 3469 | * writeout happening, and we don't want to prevent access to the directory |
| 3470 | * while waiting on the I/O. |
| 3471 | */ |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 3472 | static long do_unlinkat(int dfd, const char __user *pathname) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3473 | { |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 3474 | int error; |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 3475 | struct filename *name; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3476 | struct dentry *dentry; |
| 3477 | struct nameidata nd; |
| 3478 | struct inode *inode = NULL; |
Jeff Layton | 5d18f81 | 2012-12-20 16:38:04 -0500 | [diff] [blame] | 3479 | unsigned int lookup_flags = 0; |
| 3480 | retry: |
| 3481 | name = user_path_parent(dfd, pathname, &nd, lookup_flags); |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 3482 | if (IS_ERR(name)) |
| 3483 | return PTR_ERR(name); |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 3484 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3485 | error = -EISDIR; |
| 3486 | if (nd.last_type != LAST_NORM) |
| 3487 | goto exit1; |
OGAWA Hirofumi | 0612d9f | 2008-10-16 07:50:29 +0900 | [diff] [blame] | 3488 | |
| 3489 | nd.flags &= ~LOOKUP_PARENT; |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 3490 | error = mnt_want_write(nd.path.mnt); |
| 3491 | if (error) |
| 3492 | goto exit1; |
OGAWA Hirofumi | 0612d9f | 2008-10-16 07:50:29 +0900 | [diff] [blame] | 3493 | |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 3494 | mutex_lock_nested(&nd.path.dentry->d_inode->i_mutex, I_MUTEX_PARENT); |
Christoph Hellwig | 49705b7 | 2005-11-08 21:35:06 -0800 | [diff] [blame] | 3495 | dentry = lookup_hash(&nd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3496 | error = PTR_ERR(dentry); |
| 3497 | if (!IS_ERR(dentry)) { |
| 3498 | /* Why not before? Because we want correct error value */ |
Török Edwin | 50338b8 | 2011-06-16 00:06:14 +0300 | [diff] [blame] | 3499 | if (nd.last.name[nd.last.len]) |
| 3500 | goto slashes; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3501 | inode = dentry->d_inode; |
Török Edwin | 50338b8 | 2011-06-16 00:06:14 +0300 | [diff] [blame] | 3502 | if (!inode) |
Theodore Ts'o | e6bc45d | 2011-06-06 19:19:40 -0400 | [diff] [blame] | 3503 | goto slashes; |
| 3504 | ihold(inode); |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 3505 | error = security_path_unlink(&nd.path, dentry); |
| 3506 | if (error) |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 3507 | goto exit2; |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 3508 | error = vfs_unlink(nd.path.dentry->d_inode, dentry); |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 3509 | exit2: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3510 | dput(dentry); |
| 3511 | } |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 3512 | mutex_unlock(&nd.path.dentry->d_inode->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3513 | if (inode) |
| 3514 | iput(inode); /* truncate the inode here */ |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 3515 | mnt_drop_write(nd.path.mnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3516 | exit1: |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 3517 | path_put(&nd.path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3518 | putname(name); |
Jeff Layton | 5d18f81 | 2012-12-20 16:38:04 -0500 | [diff] [blame] | 3519 | if (retry_estale(error, lookup_flags)) { |
| 3520 | lookup_flags |= LOOKUP_REVAL; |
| 3521 | inode = NULL; |
| 3522 | goto retry; |
| 3523 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3524 | return error; |
| 3525 | |
| 3526 | slashes: |
| 3527 | error = !dentry->d_inode ? -ENOENT : |
| 3528 | S_ISDIR(dentry->d_inode->i_mode) ? -EISDIR : -ENOTDIR; |
| 3529 | goto exit2; |
| 3530 | } |
| 3531 | |
Heiko Carstens | 2e4d092 | 2009-01-14 14:14:31 +0100 | [diff] [blame] | 3532 | SYSCALL_DEFINE3(unlinkat, int, dfd, const char __user *, pathname, int, flag) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 3533 | { |
| 3534 | if ((flag & ~AT_REMOVEDIR) != 0) |
| 3535 | return -EINVAL; |
| 3536 | |
| 3537 | if (flag & AT_REMOVEDIR) |
| 3538 | return do_rmdir(dfd, pathname); |
| 3539 | |
| 3540 | return do_unlinkat(dfd, pathname); |
| 3541 | } |
| 3542 | |
Heiko Carstens | 3480b25 | 2009-01-14 14:14:16 +0100 | [diff] [blame] | 3543 | SYSCALL_DEFINE1(unlink, const char __user *, pathname) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 3544 | { |
| 3545 | return do_unlinkat(AT_FDCWD, pathname); |
| 3546 | } |
| 3547 | |
Miklos Szeredi | db2e747 | 2008-06-24 16:50:16 +0200 | [diff] [blame] | 3548 | int vfs_symlink(struct inode *dir, struct dentry *dentry, const char *oldname) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3549 | { |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 3550 | int error = may_create(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3551 | |
| 3552 | if (error) |
| 3553 | return error; |
| 3554 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 3555 | if (!dir->i_op->symlink) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3556 | return -EPERM; |
| 3557 | |
| 3558 | error = security_inode_symlink(dir, dentry, oldname); |
| 3559 | if (error) |
| 3560 | return error; |
| 3561 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3562 | error = dir->i_op->symlink(dir, dentry, oldname); |
Stephen Smalley | a74574a | 2005-09-09 13:01:44 -0700 | [diff] [blame] | 3563 | if (!error) |
Amy Griffis | f38aa94 | 2005-11-03 15:57:06 +0000 | [diff] [blame] | 3564 | fsnotify_create(dir, dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3565 | return error; |
| 3566 | } |
| 3567 | |
Heiko Carstens | 2e4d092 | 2009-01-14 14:14:31 +0100 | [diff] [blame] | 3568 | SYSCALL_DEFINE3(symlinkat, const char __user *, oldname, |
| 3569 | int, newdfd, const char __user *, newname) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3570 | { |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 3571 | int error; |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 3572 | struct filename *from; |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 3573 | struct dentry *dentry; |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3574 | struct path path; |
Jeff Layton | f46d356 | 2012-12-11 12:10:08 -0500 | [diff] [blame] | 3575 | unsigned int lookup_flags = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3576 | |
| 3577 | from = getname(oldname); |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 3578 | if (IS_ERR(from)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3579 | return PTR_ERR(from); |
Jeff Layton | f46d356 | 2012-12-11 12:10:08 -0500 | [diff] [blame] | 3580 | retry: |
| 3581 | dentry = user_path_create(newdfd, newname, &path, lookup_flags); |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 3582 | error = PTR_ERR(dentry); |
| 3583 | if (IS_ERR(dentry)) |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3584 | goto out_putname; |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 3585 | |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 3586 | error = security_path_symlink(&path, dentry, from->name); |
Al Viro | a8104a9 | 2012-07-20 02:25:00 +0400 | [diff] [blame] | 3587 | if (!error) |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 3588 | error = vfs_symlink(path.dentry->d_inode, dentry, from->name); |
Al Viro | 921a165 | 2012-07-20 01:15:31 +0400 | [diff] [blame] | 3589 | done_path_create(&path, dentry); |
Jeff Layton | f46d356 | 2012-12-11 12:10:08 -0500 | [diff] [blame] | 3590 | if (retry_estale(error, lookup_flags)) { |
| 3591 | lookup_flags |= LOOKUP_REVAL; |
| 3592 | goto retry; |
| 3593 | } |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 3594 | out_putname: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3595 | putname(from); |
| 3596 | return error; |
| 3597 | } |
| 3598 | |
Heiko Carstens | 3480b25 | 2009-01-14 14:14:16 +0100 | [diff] [blame] | 3599 | SYSCALL_DEFINE2(symlink, const char __user *, oldname, const char __user *, newname) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 3600 | { |
| 3601 | return sys_symlinkat(oldname, AT_FDCWD, newname); |
| 3602 | } |
| 3603 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3604 | int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry) |
| 3605 | { |
| 3606 | struct inode *inode = old_dentry->d_inode; |
Al Viro | 8de5277 | 2012-02-06 12:45:27 -0500 | [diff] [blame] | 3607 | unsigned max_links = dir->i_sb->s_max_links; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3608 | int error; |
| 3609 | |
| 3610 | if (!inode) |
| 3611 | return -ENOENT; |
| 3612 | |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 3613 | error = may_create(dir, new_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3614 | if (error) |
| 3615 | return error; |
| 3616 | |
| 3617 | if (dir->i_sb != inode->i_sb) |
| 3618 | return -EXDEV; |
| 3619 | |
| 3620 | /* |
| 3621 | * A link to an append-only or immutable file cannot be created. |
| 3622 | */ |
| 3623 | if (IS_APPEND(inode) || IS_IMMUTABLE(inode)) |
| 3624 | return -EPERM; |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 3625 | if (!dir->i_op->link) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3626 | return -EPERM; |
Tetsuo Handa | 7e79eed | 2008-06-24 16:50:15 +0200 | [diff] [blame] | 3627 | if (S_ISDIR(inode->i_mode)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3628 | return -EPERM; |
| 3629 | |
| 3630 | error = security_inode_link(old_dentry, dir, new_dentry); |
| 3631 | if (error) |
| 3632 | return error; |
| 3633 | |
Tetsuo Handa | 7e79eed | 2008-06-24 16:50:15 +0200 | [diff] [blame] | 3634 | mutex_lock(&inode->i_mutex); |
Aneesh Kumar K.V | aae8a97 | 2011-01-29 18:43:27 +0530 | [diff] [blame] | 3635 | /* Make sure we don't allow creating hardlink to an unlinked file */ |
Al Viro | f4e0c30 | 2013-06-11 08:34:36 +0400 | [diff] [blame] | 3636 | if (inode->i_nlink == 0 && !(inode->i_state & I_LINKABLE)) |
Aneesh Kumar K.V | aae8a97 | 2011-01-29 18:43:27 +0530 | [diff] [blame] | 3637 | error = -ENOENT; |
Al Viro | 8de5277 | 2012-02-06 12:45:27 -0500 | [diff] [blame] | 3638 | else if (max_links && inode->i_nlink >= max_links) |
| 3639 | error = -EMLINK; |
Aneesh Kumar K.V | aae8a97 | 2011-01-29 18:43:27 +0530 | [diff] [blame] | 3640 | else |
| 3641 | error = dir->i_op->link(old_dentry, dir, new_dentry); |
Al Viro | f4e0c30 | 2013-06-11 08:34:36 +0400 | [diff] [blame] | 3642 | |
| 3643 | if (!error && (inode->i_state & I_LINKABLE)) { |
| 3644 | spin_lock(&inode->i_lock); |
| 3645 | inode->i_state &= ~I_LINKABLE; |
| 3646 | spin_unlock(&inode->i_lock); |
| 3647 | } |
Tetsuo Handa | 7e79eed | 2008-06-24 16:50:15 +0200 | [diff] [blame] | 3648 | mutex_unlock(&inode->i_mutex); |
Stephen Smalley | e31e14e | 2005-09-09 13:01:45 -0700 | [diff] [blame] | 3649 | if (!error) |
Tetsuo Handa | 7e79eed | 2008-06-24 16:50:15 +0200 | [diff] [blame] | 3650 | fsnotify_link(dir, inode, new_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3651 | return error; |
| 3652 | } |
| 3653 | |
| 3654 | /* |
| 3655 | * Hardlinks are often used in delicate situations. We avoid |
| 3656 | * security-related surprises by not following symlinks on the |
| 3657 | * newname. --KAB |
| 3658 | * |
| 3659 | * We don't follow them on the oldname either to be compatible |
| 3660 | * with linux 2.0, and to avoid hard-linking to directories |
| 3661 | * and other special files. --ADM |
| 3662 | */ |
Heiko Carstens | 2e4d092 | 2009-01-14 14:14:31 +0100 | [diff] [blame] | 3663 | SYSCALL_DEFINE5(linkat, int, olddfd, const char __user *, oldname, |
| 3664 | int, newdfd, const char __user *, newname, int, flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3665 | { |
| 3666 | struct dentry *new_dentry; |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3667 | struct path old_path, new_path; |
Aneesh Kumar K.V | 11a7b37 | 2011-01-29 18:43:42 +0530 | [diff] [blame] | 3668 | int how = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3669 | int error; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3670 | |
Aneesh Kumar K.V | 11a7b37 | 2011-01-29 18:43:42 +0530 | [diff] [blame] | 3671 | if ((flags & ~(AT_SYMLINK_FOLLOW | AT_EMPTY_PATH)) != 0) |
Ulrich Drepper | c04030e | 2006-02-24 13:04:21 -0800 | [diff] [blame] | 3672 | return -EINVAL; |
Aneesh Kumar K.V | 11a7b37 | 2011-01-29 18:43:42 +0530 | [diff] [blame] | 3673 | /* |
Andy Lutomirski | bb2314b | 2013-08-01 21:44:31 -0700 | [diff] [blame^] | 3674 | * Using empty names is equivalent to using AT_SYMLINK_FOLLOW |
| 3675 | * on /proc/self/fd/<fd>. |
Aneesh Kumar K.V | 11a7b37 | 2011-01-29 18:43:42 +0530 | [diff] [blame] | 3676 | */ |
Andy Lutomirski | bb2314b | 2013-08-01 21:44:31 -0700 | [diff] [blame^] | 3677 | if (flags & AT_EMPTY_PATH) |
Aneesh Kumar K.V | 11a7b37 | 2011-01-29 18:43:42 +0530 | [diff] [blame] | 3678 | how = LOOKUP_EMPTY; |
Ulrich Drepper | c04030e | 2006-02-24 13:04:21 -0800 | [diff] [blame] | 3679 | |
Aneesh Kumar K.V | 11a7b37 | 2011-01-29 18:43:42 +0530 | [diff] [blame] | 3680 | if (flags & AT_SYMLINK_FOLLOW) |
| 3681 | how |= LOOKUP_FOLLOW; |
Jeff Layton | 442e31c | 2012-12-20 16:15:38 -0500 | [diff] [blame] | 3682 | retry: |
Aneesh Kumar K.V | 11a7b37 | 2011-01-29 18:43:42 +0530 | [diff] [blame] | 3683 | error = user_path_at(olddfd, oldname, how, &old_path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3684 | if (error) |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 3685 | return error; |
| 3686 | |
Jeff Layton | 442e31c | 2012-12-20 16:15:38 -0500 | [diff] [blame] | 3687 | new_dentry = user_path_create(newdfd, newname, &new_path, |
| 3688 | (how & LOOKUP_REVAL)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3689 | error = PTR_ERR(new_dentry); |
Dave Hansen | 6902d92 | 2006-09-30 23:29:01 -0700 | [diff] [blame] | 3690 | if (IS_ERR(new_dentry)) |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3691 | goto out; |
| 3692 | |
| 3693 | error = -EXDEV; |
| 3694 | if (old_path.mnt != new_path.mnt) |
| 3695 | goto out_dput; |
Kees Cook | 800179c | 2012-07-25 17:29:07 -0700 | [diff] [blame] | 3696 | error = may_linkat(&old_path); |
| 3697 | if (unlikely(error)) |
| 3698 | goto out_dput; |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3699 | error = security_path_link(old_path.dentry, &new_path, new_dentry); |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 3700 | if (error) |
Al Viro | a8104a9 | 2012-07-20 02:25:00 +0400 | [diff] [blame] | 3701 | goto out_dput; |
Al Viro | dae6ad8 | 2011-06-26 11:50:15 -0400 | [diff] [blame] | 3702 | error = vfs_link(old_path.dentry, new_path.dentry->d_inode, new_dentry); |
Dave Hansen | 75c3f29 | 2008-02-15 14:37:45 -0800 | [diff] [blame] | 3703 | out_dput: |
Al Viro | 921a165 | 2012-07-20 01:15:31 +0400 | [diff] [blame] | 3704 | done_path_create(&new_path, new_dentry); |
Jeff Layton | 442e31c | 2012-12-20 16:15:38 -0500 | [diff] [blame] | 3705 | if (retry_estale(error, how)) { |
| 3706 | how |= LOOKUP_REVAL; |
| 3707 | goto retry; |
| 3708 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3709 | out: |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 3710 | path_put(&old_path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3711 | |
| 3712 | return error; |
| 3713 | } |
| 3714 | |
Heiko Carstens | 3480b25 | 2009-01-14 14:14:16 +0100 | [diff] [blame] | 3715 | SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 3716 | { |
Ulrich Drepper | c04030e | 2006-02-24 13:04:21 -0800 | [diff] [blame] | 3717 | return sys_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0); |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 3718 | } |
| 3719 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3720 | /* |
| 3721 | * The worst of all namespace operations - renaming directory. "Perverted" |
| 3722 | * doesn't even start to describe it. Somebody in UCB had a heck of a trip... |
| 3723 | * Problems: |
| 3724 | * a) we can get into loop creation. Check is done in is_subdir(). |
| 3725 | * b) race potential - two innocent renames can create a loop together. |
| 3726 | * 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] | 3727 | * 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] | 3728 | * story. |
| 3729 | * c) we have to lock _three_ objects - parents and victim (if it exists). |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 3730 | * 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] | 3731 | * whether the target exists). Solution: try to be smart with locking |
| 3732 | * 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] | 3733 | * 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] | 3734 | * move will be locked. Thus we can rank directories by the tree |
| 3735 | * (ancestors first) and rank all non-directories after them. |
| 3736 | * That works since everybody except rename does "lock parent, lookup, |
Arjan van de Ven | a11f3a0 | 2006-03-23 03:00:33 -0800 | [diff] [blame] | 3737 | * lock child" and rename is under ->s_vfs_rename_mutex. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3738 | * HOWEVER, it relies on the assumption that any object with ->lookup() |
| 3739 | * has no more than 1 dentry. If "hybrid" objects will ever appear, |
| 3740 | * 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] | 3741 | * 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] | 3742 | * 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] | 3743 | * in the fhandle_to_dentry code. [FIXME - current nfsfh.c relies on |
Adam Buchbinder | c41b20e | 2009-12-11 16:35:39 -0500 | [diff] [blame] | 3744 | * ->i_mutex on parents, which works but leads to some truly excessive |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3745 | * locking]. |
| 3746 | */ |
Adrian Bunk | 75c96f8 | 2005-05-05 16:16:09 -0700 | [diff] [blame] | 3747 | static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry, |
| 3748 | struct inode *new_dir, struct dentry *new_dentry) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3749 | { |
| 3750 | int error = 0; |
Sage Weil | 9055cba | 2011-05-24 13:06:12 -0700 | [diff] [blame] | 3751 | struct inode *target = new_dentry->d_inode; |
Al Viro | 8de5277 | 2012-02-06 12:45:27 -0500 | [diff] [blame] | 3752 | unsigned max_links = new_dir->i_sb->s_max_links; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3753 | |
| 3754 | /* |
| 3755 | * If we are going to change the parent - check write permissions, |
| 3756 | * we'll need to flip '..'. |
| 3757 | */ |
| 3758 | if (new_dir != old_dir) { |
Al Viro | f419a2e | 2008-07-22 00:07:17 -0400 | [diff] [blame] | 3759 | error = inode_permission(old_dentry->d_inode, MAY_WRITE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3760 | if (error) |
| 3761 | return error; |
| 3762 | } |
| 3763 | |
| 3764 | error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry); |
| 3765 | if (error) |
| 3766 | return error; |
| 3767 | |
Al Viro | 1d2ef59 | 2011-09-14 18:55:41 +0100 | [diff] [blame] | 3768 | dget(new_dentry); |
Al Viro | d83c49f | 2010-04-30 17:17:09 -0400 | [diff] [blame] | 3769 | if (target) |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 3770 | mutex_lock(&target->i_mutex); |
Sage Weil | 9055cba | 2011-05-24 13:06:12 -0700 | [diff] [blame] | 3771 | |
| 3772 | error = -EBUSY; |
| 3773 | if (d_mountpoint(old_dentry) || d_mountpoint(new_dentry)) |
| 3774 | goto out; |
| 3775 | |
Al Viro | 8de5277 | 2012-02-06 12:45:27 -0500 | [diff] [blame] | 3776 | error = -EMLINK; |
| 3777 | if (max_links && !target && new_dir != old_dir && |
| 3778 | new_dir->i_nlink >= max_links) |
| 3779 | goto out; |
| 3780 | |
Sage Weil | 3cebde2 | 2011-05-29 21:20:59 -0700 | [diff] [blame] | 3781 | if (target) |
| 3782 | shrink_dcache_parent(new_dentry); |
Sage Weil | 9055cba | 2011-05-24 13:06:12 -0700 | [diff] [blame] | 3783 | error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry); |
| 3784 | if (error) |
| 3785 | goto out; |
| 3786 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3787 | if (target) { |
Sage Weil | 9055cba | 2011-05-24 13:06:12 -0700 | [diff] [blame] | 3788 | target->i_flags |= S_DEAD; |
| 3789 | dont_mount(new_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3790 | } |
Sage Weil | 9055cba | 2011-05-24 13:06:12 -0700 | [diff] [blame] | 3791 | out: |
| 3792 | if (target) |
| 3793 | mutex_unlock(&target->i_mutex); |
Al Viro | 1d2ef59 | 2011-09-14 18:55:41 +0100 | [diff] [blame] | 3794 | dput(new_dentry); |
Stephen Smalley | e31e14e | 2005-09-09 13:01:45 -0700 | [diff] [blame] | 3795 | if (!error) |
Mark Fasheh | 349457c | 2006-09-08 14:22:21 -0700 | [diff] [blame] | 3796 | if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) |
| 3797 | d_move(old_dentry,new_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3798 | return error; |
| 3799 | } |
| 3800 | |
Adrian Bunk | 75c96f8 | 2005-05-05 16:16:09 -0700 | [diff] [blame] | 3801 | static int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry, |
| 3802 | struct inode *new_dir, struct dentry *new_dentry) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3803 | { |
Sage Weil | 51892bb | 2011-05-24 13:06:13 -0700 | [diff] [blame] | 3804 | struct inode *target = new_dentry->d_inode; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3805 | int error; |
| 3806 | |
| 3807 | error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry); |
| 3808 | if (error) |
| 3809 | return error; |
| 3810 | |
| 3811 | dget(new_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3812 | if (target) |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 3813 | mutex_lock(&target->i_mutex); |
Sage Weil | 51892bb | 2011-05-24 13:06:13 -0700 | [diff] [blame] | 3814 | |
| 3815 | error = -EBUSY; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3816 | if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry)) |
Sage Weil | 51892bb | 2011-05-24 13:06:13 -0700 | [diff] [blame] | 3817 | goto out; |
| 3818 | |
| 3819 | error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry); |
| 3820 | if (error) |
| 3821 | goto out; |
| 3822 | |
| 3823 | if (target) |
| 3824 | dont_mount(new_dentry); |
| 3825 | if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) |
| 3826 | d_move(old_dentry, new_dentry); |
| 3827 | out: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3828 | if (target) |
Jes Sorensen | 1b1dcc1 | 2006-01-09 15:59:24 -0800 | [diff] [blame] | 3829 | mutex_unlock(&target->i_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3830 | dput(new_dentry); |
| 3831 | return error; |
| 3832 | } |
| 3833 | |
| 3834 | int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, |
| 3835 | struct inode *new_dir, struct dentry *new_dentry) |
| 3836 | { |
| 3837 | int error; |
| 3838 | int is_dir = S_ISDIR(old_dentry->d_inode->i_mode); |
Eric Paris | 59b0df2 | 2010-02-08 12:53:52 -0500 | [diff] [blame] | 3839 | const unsigned char *old_name; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3840 | |
| 3841 | if (old_dentry->d_inode == new_dentry->d_inode) |
| 3842 | return 0; |
| 3843 | |
| 3844 | error = may_delete(old_dir, old_dentry, is_dir); |
| 3845 | if (error) |
| 3846 | return error; |
| 3847 | |
| 3848 | if (!new_dentry->d_inode) |
Miklos Szeredi | a95164d | 2008-07-30 15:08:48 +0200 | [diff] [blame] | 3849 | error = may_create(new_dir, new_dentry); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3850 | else |
| 3851 | error = may_delete(new_dir, new_dentry, is_dir); |
| 3852 | if (error) |
| 3853 | return error; |
| 3854 | |
Al Viro | acfa438 | 2008-12-04 10:06:33 -0500 | [diff] [blame] | 3855 | if (!old_dir->i_op->rename) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3856 | return -EPERM; |
| 3857 | |
Robert Love | 0eeca28 | 2005-07-12 17:06:03 -0400 | [diff] [blame] | 3858 | old_name = fsnotify_oldname_init(old_dentry->d_name.name); |
| 3859 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3860 | if (is_dir) |
| 3861 | error = vfs_rename_dir(old_dir,old_dentry,new_dir,new_dentry); |
| 3862 | else |
| 3863 | error = vfs_rename_other(old_dir,old_dentry,new_dir,new_dentry); |
Al Viro | 123df29 | 2009-12-25 04:57:57 -0500 | [diff] [blame] | 3864 | if (!error) |
| 3865 | fsnotify_move(old_dir, new_dir, old_name, is_dir, |
Al Viro | 5a190ae | 2007-06-07 12:19:32 -0400 | [diff] [blame] | 3866 | new_dentry->d_inode, old_dentry); |
Robert Love | 0eeca28 | 2005-07-12 17:06:03 -0400 | [diff] [blame] | 3867 | fsnotify_oldname_free(old_name); |
| 3868 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3869 | return error; |
| 3870 | } |
| 3871 | |
Heiko Carstens | 2e4d092 | 2009-01-14 14:14:31 +0100 | [diff] [blame] | 3872 | SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname, |
| 3873 | int, newdfd, const char __user *, newname) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3874 | { |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 3875 | struct dentry *old_dir, *new_dir; |
| 3876 | struct dentry *old_dentry, *new_dentry; |
| 3877 | struct dentry *trap; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3878 | struct nameidata oldnd, newnd; |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 3879 | struct filename *from; |
| 3880 | struct filename *to; |
Jeff Layton | c6a9428 | 2012-12-11 12:10:10 -0500 | [diff] [blame] | 3881 | unsigned int lookup_flags = 0; |
| 3882 | bool should_retry = false; |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 3883 | int error; |
Jeff Layton | c6a9428 | 2012-12-11 12:10:10 -0500 | [diff] [blame] | 3884 | retry: |
| 3885 | from = user_path_parent(olddfd, oldname, &oldnd, lookup_flags); |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 3886 | if (IS_ERR(from)) { |
| 3887 | error = PTR_ERR(from); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3888 | goto exit; |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 3889 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3890 | |
Jeff Layton | c6a9428 | 2012-12-11 12:10:10 -0500 | [diff] [blame] | 3891 | to = user_path_parent(newdfd, newname, &newnd, lookup_flags); |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 3892 | if (IS_ERR(to)) { |
| 3893 | error = PTR_ERR(to); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3894 | goto exit1; |
Jeff Layton | 91a27b2 | 2012-10-10 15:25:28 -0400 | [diff] [blame] | 3895 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3896 | |
| 3897 | error = -EXDEV; |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 3898 | if (oldnd.path.mnt != newnd.path.mnt) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3899 | goto exit2; |
| 3900 | |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 3901 | old_dir = oldnd.path.dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3902 | error = -EBUSY; |
| 3903 | if (oldnd.last_type != LAST_NORM) |
| 3904 | goto exit2; |
| 3905 | |
Jan Blunck | 4ac9137 | 2008-02-14 19:34:32 -0800 | [diff] [blame] | 3906 | new_dir = newnd.path.dentry; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3907 | if (newnd.last_type != LAST_NORM) |
| 3908 | goto exit2; |
| 3909 | |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 3910 | error = mnt_want_write(oldnd.path.mnt); |
| 3911 | if (error) |
| 3912 | goto exit2; |
| 3913 | |
OGAWA Hirofumi | 0612d9f | 2008-10-16 07:50:29 +0900 | [diff] [blame] | 3914 | oldnd.flags &= ~LOOKUP_PARENT; |
| 3915 | newnd.flags &= ~LOOKUP_PARENT; |
OGAWA Hirofumi | 4e9ed2f | 2008-10-16 07:50:29 +0900 | [diff] [blame] | 3916 | newnd.flags |= LOOKUP_RENAME_TARGET; |
OGAWA Hirofumi | 0612d9f | 2008-10-16 07:50:29 +0900 | [diff] [blame] | 3917 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3918 | trap = lock_rename(new_dir, old_dir); |
| 3919 | |
Christoph Hellwig | 49705b7 | 2005-11-08 21:35:06 -0800 | [diff] [blame] | 3920 | old_dentry = lookup_hash(&oldnd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3921 | error = PTR_ERR(old_dentry); |
| 3922 | if (IS_ERR(old_dentry)) |
| 3923 | goto exit3; |
| 3924 | /* source must exist */ |
| 3925 | error = -ENOENT; |
| 3926 | if (!old_dentry->d_inode) |
| 3927 | goto exit4; |
| 3928 | /* unless the source is a directory trailing slashes give -ENOTDIR */ |
| 3929 | if (!S_ISDIR(old_dentry->d_inode->i_mode)) { |
| 3930 | error = -ENOTDIR; |
| 3931 | if (oldnd.last.name[oldnd.last.len]) |
| 3932 | goto exit4; |
| 3933 | if (newnd.last.name[newnd.last.len]) |
| 3934 | goto exit4; |
| 3935 | } |
| 3936 | /* source should not be ancestor of target */ |
| 3937 | error = -EINVAL; |
| 3938 | if (old_dentry == trap) |
| 3939 | goto exit4; |
Christoph Hellwig | 49705b7 | 2005-11-08 21:35:06 -0800 | [diff] [blame] | 3940 | new_dentry = lookup_hash(&newnd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3941 | error = PTR_ERR(new_dentry); |
| 3942 | if (IS_ERR(new_dentry)) |
| 3943 | goto exit4; |
| 3944 | /* target should not be an ancestor of source */ |
| 3945 | error = -ENOTEMPTY; |
| 3946 | if (new_dentry == trap) |
| 3947 | goto exit5; |
| 3948 | |
Kentaro Takeda | be6d3e5 | 2008-12-17 13:24:15 +0900 | [diff] [blame] | 3949 | error = security_path_rename(&oldnd.path, old_dentry, |
| 3950 | &newnd.path, new_dentry); |
| 3951 | if (error) |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 3952 | goto exit5; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3953 | error = vfs_rename(old_dir->d_inode, old_dentry, |
| 3954 | new_dir->d_inode, new_dentry); |
| 3955 | exit5: |
| 3956 | dput(new_dentry); |
| 3957 | exit4: |
| 3958 | dput(old_dentry); |
| 3959 | exit3: |
| 3960 | unlock_rename(new_dir, old_dir); |
Jan Kara | c30dabf | 2012-06-12 16:20:30 +0200 | [diff] [blame] | 3961 | mnt_drop_write(oldnd.path.mnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3962 | exit2: |
Jeff Layton | c6a9428 | 2012-12-11 12:10:10 -0500 | [diff] [blame] | 3963 | if (retry_estale(error, lookup_flags)) |
| 3964 | should_retry = true; |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 3965 | path_put(&newnd.path); |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 3966 | putname(to); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3967 | exit1: |
Jan Blunck | 1d957f9 | 2008-02-14 19:34:35 -0800 | [diff] [blame] | 3968 | path_put(&oldnd.path); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3969 | putname(from); |
Jeff Layton | c6a9428 | 2012-12-11 12:10:10 -0500 | [diff] [blame] | 3970 | if (should_retry) { |
| 3971 | should_retry = false; |
| 3972 | lookup_flags |= LOOKUP_REVAL; |
| 3973 | goto retry; |
| 3974 | } |
Al Viro | 2ad94ae | 2008-07-21 09:32:51 -0400 | [diff] [blame] | 3975 | exit: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3976 | return error; |
| 3977 | } |
| 3978 | |
Heiko Carstens | a26eab2 | 2009-01-14 14:14:17 +0100 | [diff] [blame] | 3979 | SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newname) |
Ulrich Drepper | 5590ff0 | 2006-01-18 17:43:53 -0800 | [diff] [blame] | 3980 | { |
| 3981 | return sys_renameat(AT_FDCWD, oldname, AT_FDCWD, newname); |
| 3982 | } |
| 3983 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3984 | int vfs_readlink(struct dentry *dentry, char __user *buffer, int buflen, const char *link) |
| 3985 | { |
| 3986 | int len; |
| 3987 | |
| 3988 | len = PTR_ERR(link); |
| 3989 | if (IS_ERR(link)) |
| 3990 | goto out; |
| 3991 | |
| 3992 | len = strlen(link); |
| 3993 | if (len > (unsigned) buflen) |
| 3994 | len = buflen; |
| 3995 | if (copy_to_user(buffer, link, len)) |
| 3996 | len = -EFAULT; |
| 3997 | out: |
| 3998 | return len; |
| 3999 | } |
| 4000 | |
| 4001 | /* |
| 4002 | * A helper for ->readlink(). This should be used *ONLY* for symlinks that |
| 4003 | * have ->follow_link() touching nd only in nd_set_link(). Using (or not |
| 4004 | * using) it for any given inode is up to filesystem. |
| 4005 | */ |
| 4006 | int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen) |
| 4007 | { |
| 4008 | struct nameidata nd; |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 4009 | void *cookie; |
Marcin Slusarz | 694a176 | 2008-06-09 16:40:37 -0700 | [diff] [blame] | 4010 | int res; |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 4011 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4012 | nd.depth = 0; |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 4013 | cookie = dentry->d_inode->i_op->follow_link(dentry, &nd); |
Marcin Slusarz | 694a176 | 2008-06-09 16:40:37 -0700 | [diff] [blame] | 4014 | if (IS_ERR(cookie)) |
| 4015 | return PTR_ERR(cookie); |
| 4016 | |
| 4017 | res = vfs_readlink(dentry, buffer, buflen, nd_get_link(&nd)); |
| 4018 | if (dentry->d_inode->i_op->put_link) |
| 4019 | dentry->d_inode->i_op->put_link(dentry, &nd, cookie); |
| 4020 | return res; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4021 | } |
| 4022 | |
| 4023 | int vfs_follow_link(struct nameidata *nd, const char *link) |
| 4024 | { |
| 4025 | return __vfs_follow_link(nd, link); |
| 4026 | } |
| 4027 | |
| 4028 | /* get the link contents into pagecache */ |
| 4029 | static char *page_getlink(struct dentry * dentry, struct page **ppage) |
| 4030 | { |
Duane Griffin | ebd09ab | 2008-12-19 20:47:12 +0000 | [diff] [blame] | 4031 | char *kaddr; |
| 4032 | struct page *page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4033 | struct address_space *mapping = dentry->d_inode->i_mapping; |
Pekka Enberg | 090d2b1 | 2006-06-23 02:05:08 -0700 | [diff] [blame] | 4034 | page = read_mapping_page(mapping, 0, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4035 | if (IS_ERR(page)) |
Nick Piggin | 6fe6900 | 2007-05-06 14:49:04 -0700 | [diff] [blame] | 4036 | return (char*)page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4037 | *ppage = page; |
Duane Griffin | ebd09ab | 2008-12-19 20:47:12 +0000 | [diff] [blame] | 4038 | kaddr = kmap(page); |
| 4039 | nd_terminate_link(kaddr, dentry->d_inode->i_size, PAGE_SIZE - 1); |
| 4040 | return kaddr; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4041 | } |
| 4042 | |
| 4043 | int page_readlink(struct dentry *dentry, char __user *buffer, int buflen) |
| 4044 | { |
| 4045 | struct page *page = NULL; |
| 4046 | char *s = page_getlink(dentry, &page); |
| 4047 | int res = vfs_readlink(dentry,buffer,buflen,s); |
| 4048 | if (page) { |
| 4049 | kunmap(page); |
| 4050 | page_cache_release(page); |
| 4051 | } |
| 4052 | return res; |
| 4053 | } |
| 4054 | |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 4055 | void *page_follow_link_light(struct dentry *dentry, struct nameidata *nd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4056 | { |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 4057 | struct page *page = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4058 | nd_set_link(nd, page_getlink(dentry, &page)); |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 4059 | return page; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4060 | } |
| 4061 | |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 4062 | void page_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4063 | { |
Linus Torvalds | cc314ee | 2005-08-19 18:02:56 -0700 | [diff] [blame] | 4064 | struct page *page = cookie; |
| 4065 | |
| 4066 | if (page) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4067 | kunmap(page); |
| 4068 | page_cache_release(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4069 | } |
| 4070 | } |
| 4071 | |
Nick Piggin | 54566b2 | 2009-01-04 12:00:53 -0800 | [diff] [blame] | 4072 | /* |
| 4073 | * The nofs argument instructs pagecache_write_begin to pass AOP_FLAG_NOFS |
| 4074 | */ |
| 4075 | 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] | 4076 | { |
| 4077 | struct address_space *mapping = inode->i_mapping; |
Kirill Korotaev | 0adb25d | 2006-03-11 03:27:13 -0800 | [diff] [blame] | 4078 | struct page *page; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 4079 | void *fsdata; |
Dmitriy Monakhov | beb497a | 2007-02-16 01:27:18 -0800 | [diff] [blame] | 4080 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4081 | char *kaddr; |
Nick Piggin | 54566b2 | 2009-01-04 12:00:53 -0800 | [diff] [blame] | 4082 | unsigned int flags = AOP_FLAG_UNINTERRUPTIBLE; |
| 4083 | if (nofs) |
| 4084 | flags |= AOP_FLAG_NOFS; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4085 | |
NeilBrown | 7e53cac | 2006-03-25 03:07:57 -0800 | [diff] [blame] | 4086 | retry: |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 4087 | err = pagecache_write_begin(NULL, mapping, 0, len-1, |
Nick Piggin | 54566b2 | 2009-01-04 12:00:53 -0800 | [diff] [blame] | 4088 | flags, &page, &fsdata); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4089 | if (err) |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 4090 | goto fail; |
| 4091 | |
Cong Wang | e8e3c3d | 2011-11-25 23:14:27 +0800 | [diff] [blame] | 4092 | kaddr = kmap_atomic(page); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4093 | memcpy(kaddr, symname, len-1); |
Cong Wang | e8e3c3d | 2011-11-25 23:14:27 +0800 | [diff] [blame] | 4094 | kunmap_atomic(kaddr); |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 4095 | |
| 4096 | err = pagecache_write_end(NULL, mapping, 0, len-1, len-1, |
| 4097 | page, fsdata); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4098 | if (err < 0) |
| 4099 | goto fail; |
Nick Piggin | afddba4 | 2007-10-16 01:25:01 -0700 | [diff] [blame] | 4100 | if (err < len-1) |
| 4101 | goto retry; |
| 4102 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4103 | mark_inode_dirty(inode); |
| 4104 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4105 | fail: |
| 4106 | return err; |
| 4107 | } |
| 4108 | |
Kirill Korotaev | 0adb25d | 2006-03-11 03:27:13 -0800 | [diff] [blame] | 4109 | int page_symlink(struct inode *inode, const char *symname, int len) |
| 4110 | { |
| 4111 | return __page_symlink(inode, symname, len, |
Nick Piggin | 54566b2 | 2009-01-04 12:00:53 -0800 | [diff] [blame] | 4112 | !(mapping_gfp_mask(inode->i_mapping) & __GFP_FS)); |
Kirill Korotaev | 0adb25d | 2006-03-11 03:27:13 -0800 | [diff] [blame] | 4113 | } |
| 4114 | |
Arjan van de Ven | 92e1d5b | 2007-02-12 00:55:39 -0800 | [diff] [blame] | 4115 | const struct inode_operations page_symlink_inode_operations = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4116 | .readlink = generic_readlink, |
| 4117 | .follow_link = page_follow_link_light, |
| 4118 | .put_link = page_put_link, |
| 4119 | }; |
| 4120 | |
Al Viro | 2d8f303 | 2008-07-22 09:59:21 -0400 | [diff] [blame] | 4121 | EXPORT_SYMBOL(user_path_at); |
David Howells | cc53ce5 | 2011-01-14 18:45:26 +0000 | [diff] [blame] | 4122 | EXPORT_SYMBOL(follow_down_one); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4123 | EXPORT_SYMBOL(follow_down); |
| 4124 | EXPORT_SYMBOL(follow_up); |
Al Viro | f6d2ac5 | 2012-08-26 12:55:54 -0400 | [diff] [blame] | 4125 | EXPORT_SYMBOL(get_write_access); /* nfsd */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4126 | EXPORT_SYMBOL(lock_rename); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4127 | EXPORT_SYMBOL(lookup_one_len); |
| 4128 | EXPORT_SYMBOL(page_follow_link_light); |
| 4129 | EXPORT_SYMBOL(page_put_link); |
| 4130 | EXPORT_SYMBOL(page_readlink); |
Kirill Korotaev | 0adb25d | 2006-03-11 03:27:13 -0800 | [diff] [blame] | 4131 | EXPORT_SYMBOL(__page_symlink); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4132 | EXPORT_SYMBOL(page_symlink); |
| 4133 | EXPORT_SYMBOL(page_symlink_inode_operations); |
Al Viro | d181146 | 2008-08-02 00:49:18 -0400 | [diff] [blame] | 4134 | EXPORT_SYMBOL(kern_path); |
Josef 'Jeff' Sipek | 16f1820 | 2007-07-19 01:48:18 -0700 | [diff] [blame] | 4135 | EXPORT_SYMBOL(vfs_path_lookup); |
Al Viro | f419a2e | 2008-07-22 00:07:17 -0400 | [diff] [blame] | 4136 | EXPORT_SYMBOL(inode_permission); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4137 | EXPORT_SYMBOL(unlock_rename); |
| 4138 | EXPORT_SYMBOL(vfs_create); |
| 4139 | EXPORT_SYMBOL(vfs_follow_link); |
| 4140 | EXPORT_SYMBOL(vfs_link); |
| 4141 | EXPORT_SYMBOL(vfs_mkdir); |
| 4142 | EXPORT_SYMBOL(vfs_mknod); |
| 4143 | EXPORT_SYMBOL(generic_permission); |
| 4144 | EXPORT_SYMBOL(vfs_readlink); |
| 4145 | EXPORT_SYMBOL(vfs_rename); |
| 4146 | EXPORT_SYMBOL(vfs_rmdir); |
| 4147 | EXPORT_SYMBOL(vfs_symlink); |
| 4148 | EXPORT_SYMBOL(vfs_unlink); |
| 4149 | EXPORT_SYMBOL(dentry_unhash); |
| 4150 | EXPORT_SYMBOL(generic_readlink); |