Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 1 | /* |
| 2 | * |
| 3 | * Copyright (C) 2011 Novell Inc. |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify it |
| 6 | * under the terms of the GNU General Public License version 2 as published by |
| 7 | * the Free Software Foundation. |
| 8 | */ |
| 9 | |
| 10 | #include <linux/fs.h> |
| 11 | #include <linux/slab.h> |
Ingo Molnar | 5b825c3 | 2017-02-02 17:54:15 +0100 | [diff] [blame] | 12 | #include <linux/cred.h> |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 13 | #include <linux/xattr.h> |
Miklos Szeredi | 5201dc4 | 2016-09-01 11:11:59 +0200 | [diff] [blame] | 14 | #include <linux/posix_acl.h> |
Amir Goldstein | 5f8415d | 2017-06-20 15:35:14 +0300 | [diff] [blame] | 15 | #include <linux/ratelimit.h> |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 16 | #include "overlayfs.h" |
| 17 | |
Chandan Rajendra | ba1e563 | 2017-07-24 01:57:54 -0500 | [diff] [blame] | 18 | |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 19 | int ovl_setattr(struct dentry *dentry, struct iattr *attr) |
| 20 | { |
| 21 | int err; |
| 22 | struct dentry *upperdentry; |
Vivek Goyal | 1175b6b | 2016-07-01 16:34:28 -0400 | [diff] [blame] | 23 | const struct cred *old_cred; |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 24 | |
Miklos Szeredi | cf9a678 | 2015-12-11 16:30:49 +0100 | [diff] [blame] | 25 | /* |
| 26 | * Check for permissions before trying to copy-up. This is redundant |
| 27 | * since it will be rechecked later by ->setattr() on upper dentry. But |
| 28 | * without this, copy-up can be triggered by just about anybody. |
| 29 | * |
| 30 | * We don't initialize inode->size, which just means that |
| 31 | * inode_newsize_ok() will always check against MAX_LFS_FILESIZE and not |
| 32 | * check for a swapfile (which this won't be anyway). |
| 33 | */ |
Jan Kara | 31051c8 | 2016-05-26 16:55:18 +0200 | [diff] [blame] | 34 | err = setattr_prepare(dentry, attr); |
Miklos Szeredi | cf9a678 | 2015-12-11 16:30:49 +0100 | [diff] [blame] | 35 | if (err) |
| 36 | return err; |
| 37 | |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 38 | err = ovl_want_write(dentry); |
| 39 | if (err) |
| 40 | goto out; |
| 41 | |
Miklos Szeredi | acff81e | 2015-12-04 19:18:48 +0100 | [diff] [blame] | 42 | err = ovl_copy_up(dentry); |
| 43 | if (!err) { |
| 44 | upperdentry = ovl_dentry_upper(dentry); |
| 45 | |
Miklos Szeredi | b99c2d9 | 2016-07-04 16:49:48 +0200 | [diff] [blame] | 46 | if (attr->ia_valid & (ATTR_KILL_SUID|ATTR_KILL_SGID)) |
| 47 | attr->ia_valid &= ~ATTR_MODE; |
| 48 | |
Al Viro | 5955102 | 2016-01-22 15:40:57 -0500 | [diff] [blame] | 49 | inode_lock(upperdentry->d_inode); |
Vivek Goyal | 1175b6b | 2016-07-01 16:34:28 -0400 | [diff] [blame] | 50 | old_cred = ovl_override_creds(dentry->d_sb); |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 51 | err = notify_change(upperdentry, attr, NULL); |
Vivek Goyal | 1175b6b | 2016-07-01 16:34:28 -0400 | [diff] [blame] | 52 | revert_creds(old_cred); |
Konstantin Khlebnikov | b81de06 | 2016-01-31 16:21:29 +0300 | [diff] [blame] | 53 | if (!err) |
| 54 | ovl_copyattr(upperdentry->d_inode, dentry->d_inode); |
Al Viro | 5955102 | 2016-01-22 15:40:57 -0500 | [diff] [blame] | 55 | inode_unlock(upperdentry->d_inode); |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 56 | } |
| 57 | ovl_drop_write(dentry); |
| 58 | out: |
| 59 | return err; |
| 60 | } |
| 61 | |
Amir Goldstein | da309e8 | 2017-11-08 19:39:51 +0200 | [diff] [blame^] | 62 | static int ovl_map_dev_ino(struct dentry *dentry, struct kstat *stat, |
| 63 | struct ovl_layer *lower_layer) |
| 64 | { |
| 65 | bool samefs = ovl_same_sb(dentry->d_sb); |
| 66 | |
| 67 | if (samefs) { |
| 68 | /* |
| 69 | * When all layers are on the same fs, all real inode |
| 70 | * number are unique, so we use the overlay st_dev, |
| 71 | * which is friendly to du -x. |
| 72 | */ |
| 73 | stat->dev = dentry->d_sb->s_dev; |
| 74 | } else if (S_ISDIR(dentry->d_inode->i_mode)) { |
| 75 | /* |
| 76 | * Always use the overlay st_dev for directories, so 'find |
| 77 | * -xdev' will scan the entire overlay mount and won't cross the |
| 78 | * overlay mount boundaries. |
| 79 | * |
| 80 | * If not all layers are on the same fs the pair {real st_ino; |
| 81 | * overlay st_dev} is not unique, so use the non persistent |
| 82 | * overlay st_ino for directories. |
| 83 | */ |
| 84 | stat->dev = dentry->d_sb->s_dev; |
| 85 | stat->ino = dentry->d_inode->i_ino; |
| 86 | } else if (lower_layer) { |
| 87 | /* |
| 88 | * For non-samefs setup, if we cannot map all layers st_ino |
| 89 | * to a unified address space, we need to make sure that st_dev |
| 90 | * is unique per layer. Upper layer uses real st_dev and lower |
| 91 | * layers use the unique anonymous bdev. |
| 92 | */ |
| 93 | stat->dev = lower_layer->pseudo_dev; |
| 94 | } |
| 95 | |
| 96 | return 0; |
| 97 | } |
| 98 | |
Miklos Szeredi | 5b71209 | 2017-05-05 11:38:58 +0200 | [diff] [blame] | 99 | int ovl_getattr(const struct path *path, struct kstat *stat, |
| 100 | u32 request_mask, unsigned int flags) |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 101 | { |
David Howells | a528d35 | 2017-01-31 16:46:22 +0000 | [diff] [blame] | 102 | struct dentry *dentry = path->dentry; |
Amir Goldstein | 72b608f | 2017-04-24 00:25:49 +0300 | [diff] [blame] | 103 | enum ovl_path_type type; |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 104 | struct path realpath; |
Vivek Goyal | 1175b6b | 2016-07-01 16:34:28 -0400 | [diff] [blame] | 105 | const struct cred *old_cred; |
Miklos Szeredi | 5b71209 | 2017-05-05 11:38:58 +0200 | [diff] [blame] | 106 | bool is_dir = S_ISDIR(dentry->d_inode->i_mode); |
Amir Goldstein | a0c5ad3 | 2017-11-01 00:45:40 +0200 | [diff] [blame] | 107 | bool samefs = ovl_same_sb(dentry->d_sb); |
Amir Goldstein | da309e8 | 2017-11-08 19:39:51 +0200 | [diff] [blame^] | 108 | struct ovl_layer *lower_layer = NULL; |
Vivek Goyal | 1175b6b | 2016-07-01 16:34:28 -0400 | [diff] [blame] | 109 | int err; |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 110 | |
Amir Goldstein | 72b608f | 2017-04-24 00:25:49 +0300 | [diff] [blame] | 111 | type = ovl_path_real(dentry, &realpath); |
Vivek Goyal | 1175b6b | 2016-07-01 16:34:28 -0400 | [diff] [blame] | 112 | old_cred = ovl_override_creds(dentry->d_sb); |
David Howells | a528d35 | 2017-01-31 16:46:22 +0000 | [diff] [blame] | 113 | err = vfs_getattr(&realpath, stat, request_mask, flags); |
Amir Goldstein | 72b608f | 2017-04-24 00:25:49 +0300 | [diff] [blame] | 114 | if (err) |
| 115 | goto out; |
| 116 | |
| 117 | /* |
Amir Goldstein | da309e8 | 2017-11-08 19:39:51 +0200 | [diff] [blame^] | 118 | * For non-dir or same fs, we use st_ino of the copy up origin. |
| 119 | * This guaranties constant st_dev/st_ino across copy up. |
Amir Goldstein | 72b608f | 2017-04-24 00:25:49 +0300 | [diff] [blame] | 120 | * |
Amir Goldstein | da309e8 | 2017-11-08 19:39:51 +0200 | [diff] [blame^] | 121 | * If lower filesystem supports NFS file handles, this also guaranties |
Amir Goldstein | 72b608f | 2017-04-24 00:25:49 +0300 | [diff] [blame] | 122 | * persistent st_ino across mount cycle. |
| 123 | */ |
Amir Goldstein | a0c5ad3 | 2017-11-01 00:45:40 +0200 | [diff] [blame] | 124 | if (!is_dir || samefs) { |
Amir Goldstein | da309e8 | 2017-11-08 19:39:51 +0200 | [diff] [blame^] | 125 | if (!OVL_TYPE_UPPER(type)) { |
| 126 | lower_layer = ovl_layer_lower(dentry); |
| 127 | } else if (OVL_TYPE_ORIGIN(type)) { |
Amir Goldstein | 72b608f | 2017-04-24 00:25:49 +0300 | [diff] [blame] | 128 | struct kstat lowerstat; |
Miklos Szeredi | 5b71209 | 2017-05-05 11:38:58 +0200 | [diff] [blame] | 129 | u32 lowermask = STATX_INO | (!is_dir ? STATX_NLINK : 0); |
Amir Goldstein | 72b608f | 2017-04-24 00:25:49 +0300 | [diff] [blame] | 130 | |
| 131 | ovl_path_lower(dentry, &realpath); |
| 132 | err = vfs_getattr(&realpath, &lowerstat, |
Miklos Szeredi | 5b71209 | 2017-05-05 11:38:58 +0200 | [diff] [blame] | 133 | lowermask, flags); |
Amir Goldstein | 72b608f | 2017-04-24 00:25:49 +0300 | [diff] [blame] | 134 | if (err) |
| 135 | goto out; |
| 136 | |
Amir Goldstein | 72b608f | 2017-04-24 00:25:49 +0300 | [diff] [blame] | 137 | /* |
Amir Goldstein | 359f392 | 2017-06-21 15:28:41 +0300 | [diff] [blame] | 138 | * Lower hardlinks may be broken on copy up to different |
Amir Goldstein | 72b608f | 2017-04-24 00:25:49 +0300 | [diff] [blame] | 139 | * upper files, so we cannot use the lower origin st_ino |
| 140 | * for those different files, even for the same fs case. |
Amir Goldstein | 86eaa13 | 2017-11-21 13:55:51 +0200 | [diff] [blame] | 141 | * |
| 142 | * Similarly, several redirected dirs can point to the |
| 143 | * same dir on a lower layer. With the "verify_lower" |
| 144 | * feature, we do not use the lower origin st_ino, if |
| 145 | * we haven't verified that this redirect is unique. |
| 146 | * |
Amir Goldstein | 359f392 | 2017-06-21 15:28:41 +0300 | [diff] [blame] | 147 | * With inodes index enabled, it is safe to use st_ino |
Amir Goldstein | 86eaa13 | 2017-11-21 13:55:51 +0200 | [diff] [blame] | 148 | * of an indexed origin. The index validates that the |
| 149 | * upper hardlink is not broken and that a redirected |
| 150 | * dir is the only redirect to that origin. |
Amir Goldstein | 72b608f | 2017-04-24 00:25:49 +0300 | [diff] [blame] | 151 | */ |
Amir Goldstein | 86eaa13 | 2017-11-21 13:55:51 +0200 | [diff] [blame] | 152 | if (ovl_test_flag(OVL_INDEX, d_inode(dentry)) || |
| 153 | (!ovl_verify_lower(dentry->d_sb) && |
Amir Goldstein | 9f99e50 | 2018-04-11 20:09:29 +0300 | [diff] [blame] | 154 | (is_dir || lowerstat.nlink == 1))) { |
Amir Goldstein | 72b608f | 2017-04-24 00:25:49 +0300 | [diff] [blame] | 155 | stat->ino = lowerstat.ino; |
Amir Goldstein | da309e8 | 2017-11-08 19:39:51 +0200 | [diff] [blame^] | 156 | lower_layer = ovl_layer_lower(dentry); |
Amir Goldstein | 9f99e50 | 2018-04-11 20:09:29 +0300 | [diff] [blame] | 157 | } |
Amir Goldstein | 72b608f | 2017-04-24 00:25:49 +0300 | [diff] [blame] | 158 | } |
Amir Goldstein | 72b608f | 2017-04-24 00:25:49 +0300 | [diff] [blame] | 159 | } |
Miklos Szeredi | 5b71209 | 2017-05-05 11:38:58 +0200 | [diff] [blame] | 160 | |
Amir Goldstein | da309e8 | 2017-11-08 19:39:51 +0200 | [diff] [blame^] | 161 | err = ovl_map_dev_ino(dentry, stat, lower_layer); |
| 162 | if (err) |
| 163 | goto out; |
| 164 | |
Miklos Szeredi | 5b71209 | 2017-05-05 11:38:58 +0200 | [diff] [blame] | 165 | /* |
| 166 | * It's probably not worth it to count subdirs to get the |
| 167 | * correct link count. nlink=1 seems to pacify 'find' and |
| 168 | * other utilities. |
| 169 | */ |
| 170 | if (is_dir && OVL_TYPE_MERGE(type)) |
| 171 | stat->nlink = 1; |
| 172 | |
Amir Goldstein | 5f8415d | 2017-06-20 15:35:14 +0300 | [diff] [blame] | 173 | /* |
| 174 | * Return the overlay inode nlinks for indexed upper inodes. |
| 175 | * Overlay inode nlink counts the union of the upper hardlinks |
| 176 | * and non-covered lower hardlinks. It does not include the upper |
| 177 | * index hardlink. |
| 178 | */ |
| 179 | if (!is_dir && ovl_test_flag(OVL_INDEX, d_inode(dentry))) |
| 180 | stat->nlink = dentry->d_inode->i_nlink; |
| 181 | |
Amir Goldstein | 72b608f | 2017-04-24 00:25:49 +0300 | [diff] [blame] | 182 | out: |
Vivek Goyal | 1175b6b | 2016-07-01 16:34:28 -0400 | [diff] [blame] | 183 | revert_creds(old_cred); |
Amir Goldstein | 72b608f | 2017-04-24 00:25:49 +0300 | [diff] [blame] | 184 | |
Vivek Goyal | 1175b6b | 2016-07-01 16:34:28 -0400 | [diff] [blame] | 185 | return err; |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 186 | } |
| 187 | |
| 188 | int ovl_permission(struct inode *inode, int mask) |
| 189 | { |
Miklos Szeredi | 09d8b58 | 2017-07-04 22:03:16 +0200 | [diff] [blame] | 190 | struct inode *upperinode = ovl_inode_upper(inode); |
| 191 | struct inode *realinode = upperinode ?: ovl_inode_lower(inode); |
Vivek Goyal | c0ca3d7 | 2016-07-01 16:34:27 -0400 | [diff] [blame] | 192 | const struct cred *old_cred; |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 193 | int err; |
| 194 | |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 195 | /* Careful in RCU walk mode */ |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 196 | if (!realinode) { |
| 197 | WARN_ON(!(mask & MAY_NOT_BLOCK)); |
Miklos Szeredi | a999d7e | 2016-07-29 12:05:23 +0200 | [diff] [blame] | 198 | return -ECHILD; |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 199 | } |
| 200 | |
Vivek Goyal | c0ca3d7 | 2016-07-01 16:34:27 -0400 | [diff] [blame] | 201 | /* |
| 202 | * Check overlay inode with the creds of task and underlying inode |
| 203 | * with creds of mounter |
| 204 | */ |
| 205 | err = generic_permission(inode, mask); |
| 206 | if (err) |
| 207 | return err; |
| 208 | |
| 209 | old_cred = ovl_override_creds(inode->i_sb); |
Miklos Szeredi | 09d8b58 | 2017-07-04 22:03:16 +0200 | [diff] [blame] | 210 | if (!upperinode && |
| 211 | !special_file(realinode->i_mode) && mask & MAY_WRITE) { |
Vivek Goyal | 754f8cb | 2016-07-01 16:34:29 -0400 | [diff] [blame] | 212 | mask &= ~(MAY_WRITE | MAY_APPEND); |
Vivek Goyal | 500cac3 | 2016-07-13 11:00:14 -0400 | [diff] [blame] | 213 | /* Make sure mounter can read file for copy up later */ |
| 214 | mask |= MAY_READ; |
| 215 | } |
Miklos Szeredi | 9c630eb | 2016-07-29 12:05:23 +0200 | [diff] [blame] | 216 | err = inode_permission(realinode, mask); |
Vivek Goyal | c0ca3d7 | 2016-07-01 16:34:27 -0400 | [diff] [blame] | 217 | revert_creds(old_cred); |
| 218 | |
| 219 | return err; |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 220 | } |
| 221 | |
Al Viro | 6b25539 | 2015-11-17 10:20:54 -0500 | [diff] [blame] | 222 | static const char *ovl_get_link(struct dentry *dentry, |
Al Viro | fceef39 | 2015-12-29 15:58:39 -0500 | [diff] [blame] | 223 | struct inode *inode, |
| 224 | struct delayed_call *done) |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 225 | { |
Vivek Goyal | 1175b6b | 2016-07-01 16:34:28 -0400 | [diff] [blame] | 226 | const struct cred *old_cred; |
| 227 | const char *p; |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 228 | |
Al Viro | 6b25539 | 2015-11-17 10:20:54 -0500 | [diff] [blame] | 229 | if (!dentry) |
| 230 | return ERR_PTR(-ECHILD); |
| 231 | |
Vivek Goyal | 1175b6b | 2016-07-01 16:34:28 -0400 | [diff] [blame] | 232 | old_cred = ovl_override_creds(dentry->d_sb); |
Miklos Szeredi | 7764235b | 2016-10-04 14:40:45 +0200 | [diff] [blame] | 233 | p = vfs_get_link(ovl_dentry_real(dentry), done); |
Vivek Goyal | 1175b6b | 2016-07-01 16:34:28 -0400 | [diff] [blame] | 234 | revert_creds(old_cred); |
| 235 | return p; |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 236 | } |
| 237 | |
Miklos Szeredi | 0956254 | 2016-08-08 15:08:49 +0200 | [diff] [blame] | 238 | bool ovl_is_private_xattr(const char *name) |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 239 | { |
Andreas Gruenbacher | fe2b759 | 2016-08-22 17:59:22 +0200 | [diff] [blame] | 240 | return strncmp(name, OVL_XATTR_PREFIX, |
| 241 | sizeof(OVL_XATTR_PREFIX) - 1) == 0; |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 242 | } |
| 243 | |
Miklos Szeredi | 1d88f18 | 2017-07-20 11:08:21 +0200 | [diff] [blame] | 244 | int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name, |
| 245 | const void *value, size_t size, int flags) |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 246 | { |
| 247 | int err; |
Miklos Szeredi | 1d88f18 | 2017-07-20 11:08:21 +0200 | [diff] [blame] | 248 | struct dentry *upperdentry = ovl_i_dentry_upper(inode); |
| 249 | struct dentry *realdentry = upperdentry ?: ovl_dentry_lower(dentry); |
Vivek Goyal | 1175b6b | 2016-07-01 16:34:28 -0400 | [diff] [blame] | 250 | const struct cred *old_cred; |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 251 | |
| 252 | err = ovl_want_write(dentry); |
| 253 | if (err) |
| 254 | goto out; |
| 255 | |
Miklos Szeredi | 1d88f18 | 2017-07-20 11:08:21 +0200 | [diff] [blame] | 256 | if (!value && !upperdentry) { |
| 257 | err = vfs_getxattr(realdentry, name, NULL, 0); |
Andreas Gruenbacher | 0e585cc | 2016-08-22 17:22:11 +0200 | [diff] [blame] | 258 | if (err < 0) |
| 259 | goto out_drop_write; |
| 260 | } |
| 261 | |
Miklos Szeredi | 1d88f18 | 2017-07-20 11:08:21 +0200 | [diff] [blame] | 262 | if (!upperdentry) { |
| 263 | err = ovl_copy_up(dentry); |
| 264 | if (err) |
| 265 | goto out_drop_write; |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 266 | |
Miklos Szeredi | 1d88f18 | 2017-07-20 11:08:21 +0200 | [diff] [blame] | 267 | realdentry = ovl_dentry_upper(dentry); |
| 268 | } |
Andreas Gruenbacher | 0e585cc | 2016-08-22 17:22:11 +0200 | [diff] [blame] | 269 | |
Vivek Goyal | 1175b6b | 2016-07-01 16:34:28 -0400 | [diff] [blame] | 270 | old_cred = ovl_override_creds(dentry->d_sb); |
Andreas Gruenbacher | 0e585cc | 2016-08-22 17:22:11 +0200 | [diff] [blame] | 271 | if (value) |
Miklos Szeredi | 1d88f18 | 2017-07-20 11:08:21 +0200 | [diff] [blame] | 272 | err = vfs_setxattr(realdentry, name, value, size, flags); |
Andreas Gruenbacher | 0e585cc | 2016-08-22 17:22:11 +0200 | [diff] [blame] | 273 | else { |
| 274 | WARN_ON(flags != XATTR_REPLACE); |
Miklos Szeredi | 1d88f18 | 2017-07-20 11:08:21 +0200 | [diff] [blame] | 275 | err = vfs_removexattr(realdentry, name); |
Andreas Gruenbacher | 0e585cc | 2016-08-22 17:22:11 +0200 | [diff] [blame] | 276 | } |
Vivek Goyal | 1175b6b | 2016-07-01 16:34:28 -0400 | [diff] [blame] | 277 | revert_creds(old_cred); |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 278 | |
| 279 | out_drop_write: |
| 280 | ovl_drop_write(dentry); |
| 281 | out: |
| 282 | return err; |
| 283 | } |
| 284 | |
Miklos Szeredi | 1d88f18 | 2017-07-20 11:08:21 +0200 | [diff] [blame] | 285 | int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name, |
Andreas Gruenbacher | 0eb45fc | 2016-08-22 17:52:55 +0200 | [diff] [blame] | 286 | void *value, size_t size) |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 287 | { |
Vivek Goyal | 1175b6b | 2016-07-01 16:34:28 -0400 | [diff] [blame] | 288 | ssize_t res; |
| 289 | const struct cred *old_cred; |
Miklos Szeredi | 1d88f18 | 2017-07-20 11:08:21 +0200 | [diff] [blame] | 290 | struct dentry *realdentry = |
| 291 | ovl_i_dentry_upper(inode) ?: ovl_dentry_lower(dentry); |
Miklos Szeredi | 5214846 | 2014-11-20 16:40:00 +0100 | [diff] [blame] | 292 | |
Vivek Goyal | 1175b6b | 2016-07-01 16:34:28 -0400 | [diff] [blame] | 293 | old_cred = ovl_override_creds(dentry->d_sb); |
| 294 | res = vfs_getxattr(realdentry, name, value, size); |
| 295 | revert_creds(old_cred); |
| 296 | return res; |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 297 | } |
| 298 | |
Miklos Szeredi | a082c6f | 2017-05-29 15:15:27 +0200 | [diff] [blame] | 299 | static bool ovl_can_list(const char *s) |
| 300 | { |
| 301 | /* List all non-trusted xatts */ |
| 302 | if (strncmp(s, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN) != 0) |
| 303 | return true; |
| 304 | |
| 305 | /* Never list trusted.overlay, list other trusted for superuser only */ |
| 306 | return !ovl_is_private_xattr(s) && capable(CAP_SYS_ADMIN); |
| 307 | } |
| 308 | |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 309 | ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size) |
| 310 | { |
Miklos Szeredi | b581755 | 2016-06-06 16:21:37 +0200 | [diff] [blame] | 311 | struct dentry *realdentry = ovl_dentry_real(dentry); |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 312 | ssize_t res; |
Miklos Szeredi | 7cb3511 | 2016-09-01 11:12:00 +0200 | [diff] [blame] | 313 | size_t len; |
| 314 | char *s; |
Vivek Goyal | 1175b6b | 2016-07-01 16:34:28 -0400 | [diff] [blame] | 315 | const struct cred *old_cred; |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 316 | |
Vivek Goyal | 1175b6b | 2016-07-01 16:34:28 -0400 | [diff] [blame] | 317 | old_cred = ovl_override_creds(dentry->d_sb); |
Miklos Szeredi | b581755 | 2016-06-06 16:21:37 +0200 | [diff] [blame] | 318 | res = vfs_listxattr(realdentry, list, size); |
Vivek Goyal | 1175b6b | 2016-07-01 16:34:28 -0400 | [diff] [blame] | 319 | revert_creds(old_cred); |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 320 | if (res <= 0 || size == 0) |
| 321 | return res; |
| 322 | |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 323 | /* filter out private xattrs */ |
Miklos Szeredi | 7cb3511 | 2016-09-01 11:12:00 +0200 | [diff] [blame] | 324 | for (s = list, len = res; len;) { |
| 325 | size_t slen = strnlen(s, len) + 1; |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 326 | |
Miklos Szeredi | 7cb3511 | 2016-09-01 11:12:00 +0200 | [diff] [blame] | 327 | /* underlying fs providing us with an broken xattr list? */ |
| 328 | if (WARN_ON(slen > len)) |
| 329 | return -EIO; |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 330 | |
Miklos Szeredi | 7cb3511 | 2016-09-01 11:12:00 +0200 | [diff] [blame] | 331 | len -= slen; |
Miklos Szeredi | a082c6f | 2017-05-29 15:15:27 +0200 | [diff] [blame] | 332 | if (!ovl_can_list(s)) { |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 333 | res -= slen; |
Miklos Szeredi | 7cb3511 | 2016-09-01 11:12:00 +0200 | [diff] [blame] | 334 | memmove(s, s + slen, len); |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 335 | } else { |
Miklos Szeredi | 7cb3511 | 2016-09-01 11:12:00 +0200 | [diff] [blame] | 336 | s += slen; |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 337 | } |
| 338 | } |
| 339 | |
| 340 | return res; |
| 341 | } |
| 342 | |
Vivek Goyal | 39a25b2 | 2016-07-01 16:34:26 -0400 | [diff] [blame] | 343 | struct posix_acl *ovl_get_acl(struct inode *inode, int type) |
| 344 | { |
Miklos Szeredi | 09d8b58 | 2017-07-04 22:03:16 +0200 | [diff] [blame] | 345 | struct inode *realinode = ovl_inode_real(inode); |
Vivek Goyal | 1175b6b | 2016-07-01 16:34:28 -0400 | [diff] [blame] | 346 | const struct cred *old_cred; |
| 347 | struct posix_acl *acl; |
Vivek Goyal | 39a25b2 | 2016-07-01 16:34:26 -0400 | [diff] [blame] | 348 | |
Miklos Szeredi | 5201dc4 | 2016-09-01 11:11:59 +0200 | [diff] [blame] | 349 | if (!IS_ENABLED(CONFIG_FS_POSIX_ACL) || !IS_POSIXACL(realinode)) |
Vivek Goyal | 39a25b2 | 2016-07-01 16:34:26 -0400 | [diff] [blame] | 350 | return NULL; |
| 351 | |
Vivek Goyal | 1175b6b | 2016-07-01 16:34:28 -0400 | [diff] [blame] | 352 | old_cred = ovl_override_creds(inode->i_sb); |
Miklos Szeredi | 5201dc4 | 2016-09-01 11:11:59 +0200 | [diff] [blame] | 353 | acl = get_acl(realinode, type); |
Vivek Goyal | 1175b6b | 2016-07-01 16:34:28 -0400 | [diff] [blame] | 354 | revert_creds(old_cred); |
| 355 | |
| 356 | return acl; |
Vivek Goyal | 39a25b2 | 2016-07-01 16:34:26 -0400 | [diff] [blame] | 357 | } |
| 358 | |
Amir Goldstein | 59be097 | 2017-06-20 15:25:46 +0300 | [diff] [blame] | 359 | static bool ovl_open_need_copy_up(struct dentry *dentry, int flags) |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 360 | { |
Amir Goldstein | aa3ff3c | 2017-10-15 18:00:20 +0300 | [diff] [blame] | 361 | /* Copy up of disconnected dentry does not set upper alias */ |
Amir Goldstein | 59be097 | 2017-06-20 15:25:46 +0300 | [diff] [blame] | 362 | if (ovl_dentry_upper(dentry) && |
Amir Goldstein | aa3ff3c | 2017-10-15 18:00:20 +0300 | [diff] [blame] | 363 | (ovl_dentry_has_upper_alias(dentry) || |
| 364 | (dentry->d_flags & DCACHE_DISCONNECTED))) |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 365 | return false; |
| 366 | |
Amir Goldstein | 59be097 | 2017-06-20 15:25:46 +0300 | [diff] [blame] | 367 | if (special_file(d_inode(dentry)->i_mode)) |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 368 | return false; |
| 369 | |
| 370 | if (!(OPEN_FMODE(flags) & FMODE_WRITE) && !(flags & O_TRUNC)) |
| 371 | return false; |
| 372 | |
| 373 | return true; |
| 374 | } |
| 375 | |
Miklos Szeredi | 2d90267 | 2016-06-30 08:53:27 +0200 | [diff] [blame] | 376 | int ovl_open_maybe_copy_up(struct dentry *dentry, unsigned int file_flags) |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 377 | { |
Miklos Szeredi | 2d90267 | 2016-06-30 08:53:27 +0200 | [diff] [blame] | 378 | int err = 0; |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 379 | |
Amir Goldstein | 59be097 | 2017-06-20 15:25:46 +0300 | [diff] [blame] | 380 | if (ovl_open_need_copy_up(dentry, file_flags)) { |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 381 | err = ovl_want_write(dentry); |
Miklos Szeredi | 2d90267 | 2016-06-30 08:53:27 +0200 | [diff] [blame] | 382 | if (!err) { |
Amir Goldstein | 9aba652 | 2016-11-12 21:36:03 +0200 | [diff] [blame] | 383 | err = ovl_copy_up_flags(dentry, file_flags); |
Miklos Szeredi | 2d90267 | 2016-06-30 08:53:27 +0200 | [diff] [blame] | 384 | ovl_drop_write(dentry); |
| 385 | } |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 386 | } |
| 387 | |
Miklos Szeredi | 2d90267 | 2016-06-30 08:53:27 +0200 | [diff] [blame] | 388 | return err; |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 389 | } |
| 390 | |
Miklos Szeredi | d719e8f | 2016-07-29 12:05:23 +0200 | [diff] [blame] | 391 | int ovl_update_time(struct inode *inode, struct timespec *ts, int flags) |
| 392 | { |
Miklos Szeredi | 8f35cf5 | 2018-04-12 12:04:50 +0200 | [diff] [blame] | 393 | if (flags & S_ATIME) { |
| 394 | struct ovl_fs *ofs = inode->i_sb->s_fs_info; |
| 395 | struct path upperpath = { |
| 396 | .mnt = ofs->upper_mnt, |
| 397 | .dentry = ovl_upperdentry_dereference(OVL_I(inode)), |
| 398 | }; |
Miklos Szeredi | d719e8f | 2016-07-29 12:05:23 +0200 | [diff] [blame] | 399 | |
Miklos Szeredi | 8f35cf5 | 2018-04-12 12:04:50 +0200 | [diff] [blame] | 400 | if (upperpath.dentry) { |
| 401 | touch_atime(&upperpath); |
| 402 | inode->i_atime = d_inode(upperpath.dentry)->i_atime; |
| 403 | } |
Miklos Szeredi | d719e8f | 2016-07-29 12:05:23 +0200 | [diff] [blame] | 404 | } |
Miklos Szeredi | d719e8f | 2016-07-29 12:05:23 +0200 | [diff] [blame] | 405 | return 0; |
| 406 | } |
| 407 | |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 408 | static const struct inode_operations ovl_file_inode_operations = { |
| 409 | .setattr = ovl_setattr, |
| 410 | .permission = ovl_permission, |
| 411 | .getattr = ovl_getattr, |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 412 | .listxattr = ovl_listxattr, |
Vivek Goyal | 39a25b2 | 2016-07-01 16:34:26 -0400 | [diff] [blame] | 413 | .get_acl = ovl_get_acl, |
Miklos Szeredi | d719e8f | 2016-07-29 12:05:23 +0200 | [diff] [blame] | 414 | .update_time = ovl_update_time, |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 415 | }; |
| 416 | |
| 417 | static const struct inode_operations ovl_symlink_inode_operations = { |
| 418 | .setattr = ovl_setattr, |
Al Viro | 6b25539 | 2015-11-17 10:20:54 -0500 | [diff] [blame] | 419 | .get_link = ovl_get_link, |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 420 | .getattr = ovl_getattr, |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 421 | .listxattr = ovl_listxattr, |
Miklos Szeredi | d719e8f | 2016-07-29 12:05:23 +0200 | [diff] [blame] | 422 | .update_time = ovl_update_time, |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 423 | }; |
| 424 | |
Amir Goldstein | b1eaa95 | 2017-01-11 12:07:46 +0200 | [diff] [blame] | 425 | /* |
| 426 | * It is possible to stack overlayfs instance on top of another |
| 427 | * overlayfs instance as lower layer. We need to annonate the |
| 428 | * stackable i_mutex locks according to stack level of the super |
| 429 | * block instance. An overlayfs instance can never be in stack |
| 430 | * depth 0 (there is always a real fs below it). An overlayfs |
| 431 | * inode lock will use the lockdep annotaion ovl_i_mutex_key[depth]. |
| 432 | * |
| 433 | * For example, here is a snip from /proc/lockdep_chains after |
| 434 | * dir_iterate of nested overlayfs: |
| 435 | * |
| 436 | * [...] &ovl_i_mutex_dir_key[depth] (stack_depth=2) |
| 437 | * [...] &ovl_i_mutex_dir_key[depth]#2 (stack_depth=1) |
| 438 | * [...] &type->i_mutex_dir_key (stack_depth=0) |
| 439 | */ |
| 440 | #define OVL_MAX_NESTING FILESYSTEM_MAX_STACK_DEPTH |
| 441 | |
| 442 | static inline void ovl_lockdep_annotate_inode_mutex_key(struct inode *inode) |
| 443 | { |
| 444 | #ifdef CONFIG_LOCKDEP |
| 445 | static struct lock_class_key ovl_i_mutex_key[OVL_MAX_NESTING]; |
| 446 | static struct lock_class_key ovl_i_mutex_dir_key[OVL_MAX_NESTING]; |
Amir Goldstein | 4eae06d | 2017-10-27 15:44:08 +0300 | [diff] [blame] | 447 | static struct lock_class_key ovl_i_lock_key[OVL_MAX_NESTING]; |
Amir Goldstein | b1eaa95 | 2017-01-11 12:07:46 +0200 | [diff] [blame] | 448 | |
| 449 | int depth = inode->i_sb->s_stack_depth - 1; |
| 450 | |
| 451 | if (WARN_ON_ONCE(depth < 0 || depth >= OVL_MAX_NESTING)) |
| 452 | depth = 0; |
| 453 | |
| 454 | if (S_ISDIR(inode->i_mode)) |
| 455 | lockdep_set_class(&inode->i_rwsem, &ovl_i_mutex_dir_key[depth]); |
| 456 | else |
| 457 | lockdep_set_class(&inode->i_rwsem, &ovl_i_mutex_key[depth]); |
Amir Goldstein | 4eae06d | 2017-10-27 15:44:08 +0300 | [diff] [blame] | 458 | |
| 459 | lockdep_set_class(&OVL_I(inode)->lock, &ovl_i_lock_key[depth]); |
Amir Goldstein | b1eaa95 | 2017-01-11 12:07:46 +0200 | [diff] [blame] | 460 | #endif |
| 461 | } |
| 462 | |
Amir Goldstein | 695b46e | 2018-03-15 23:39:01 +0200 | [diff] [blame] | 463 | static void ovl_fill_inode(struct inode *inode, umode_t mode, dev_t rdev, |
| 464 | unsigned long ino) |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 465 | { |
Amir Goldstein | 695b46e | 2018-03-15 23:39:01 +0200 | [diff] [blame] | 466 | /* |
| 467 | * When NFS export is enabled and d_ino is consistent with st_ino |
| 468 | * (samefs), set the same value to i_ino, because nfsd readdirplus |
| 469 | * compares d_ino values to i_ino values of child entries. When called |
| 470 | * from ovl_new_inode(), ino arg is 0, so i_ino will be updated to real |
| 471 | * upper inode i_ino on ovl_inode_init() or ovl_inode_update(). |
| 472 | */ |
| 473 | if (inode->i_sb->s_export_op && ovl_same_sb(inode->i_sb)) |
| 474 | inode->i_ino = ino; |
| 475 | else |
| 476 | inode->i_ino = get_next_ino(); |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 477 | inode->i_mode = mode; |
Miklos Szeredi | d719e8f | 2016-07-29 12:05:23 +0200 | [diff] [blame] | 478 | inode->i_flags |= S_NOCMTIME; |
Miklos Szeredi | 2a3a2a3 | 2016-09-01 11:11:59 +0200 | [diff] [blame] | 479 | #ifdef CONFIG_FS_POSIX_ACL |
| 480 | inode->i_acl = inode->i_default_acl = ACL_DONT_CACHE; |
| 481 | #endif |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 482 | |
Amir Goldstein | b1eaa95 | 2017-01-11 12:07:46 +0200 | [diff] [blame] | 483 | ovl_lockdep_annotate_inode_mutex_key(inode); |
| 484 | |
Miklos Szeredi | ca4c8a3 | 2016-12-16 11:02:55 +0100 | [diff] [blame] | 485 | switch (mode & S_IFMT) { |
| 486 | case S_IFREG: |
| 487 | inode->i_op = &ovl_file_inode_operations; |
| 488 | break; |
| 489 | |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 490 | case S_IFDIR: |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 491 | inode->i_op = &ovl_dir_inode_operations; |
| 492 | inode->i_fop = &ovl_dir_operations; |
| 493 | break; |
| 494 | |
| 495 | case S_IFLNK: |
| 496 | inode->i_op = &ovl_symlink_inode_operations; |
| 497 | break; |
| 498 | |
Miklos Szeredi | 51f7e52 | 2016-07-29 12:05:24 +0200 | [diff] [blame] | 499 | default: |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 500 | inode->i_op = &ovl_file_inode_operations; |
Miklos Szeredi | ca4c8a3 | 2016-12-16 11:02:55 +0100 | [diff] [blame] | 501 | init_special_inode(inode, mode, rdev); |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 502 | break; |
Miklos Szeredi | 51f7e52 | 2016-07-29 12:05:24 +0200 | [diff] [blame] | 503 | } |
| 504 | } |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 505 | |
Amir Goldstein | 5f8415d | 2017-06-20 15:35:14 +0300 | [diff] [blame] | 506 | /* |
| 507 | * With inodes index enabled, an overlay inode nlink counts the union of upper |
| 508 | * hardlinks and non-covered lower hardlinks. During the lifetime of a non-pure |
| 509 | * upper inode, the following nlink modifying operations can happen: |
| 510 | * |
| 511 | * 1. Lower hardlink copy up |
| 512 | * 2. Upper hardlink created, unlinked or renamed over |
| 513 | * 3. Lower hardlink whiteout or renamed over |
| 514 | * |
| 515 | * For the first, copy up case, the union nlink does not change, whether the |
| 516 | * operation succeeds or fails, but the upper inode nlink may change. |
| 517 | * Therefore, before copy up, we store the union nlink value relative to the |
| 518 | * lower inode nlink in the index inode xattr trusted.overlay.nlink. |
| 519 | * |
| 520 | * For the second, upper hardlink case, the union nlink should be incremented |
| 521 | * or decremented IFF the operation succeeds, aligned with nlink change of the |
| 522 | * upper inode. Therefore, before link/unlink/rename, we store the union nlink |
| 523 | * value relative to the upper inode nlink in the index inode. |
| 524 | * |
| 525 | * For the last, lower cover up case, we simplify things by preceding the |
| 526 | * whiteout or cover up with copy up. This makes sure that there is an index |
| 527 | * upper inode where the nlink xattr can be stored before the copied up upper |
| 528 | * entry is unlink. |
| 529 | */ |
| 530 | #define OVL_NLINK_ADD_UPPER (1 << 0) |
| 531 | |
| 532 | /* |
| 533 | * On-disk format for indexed nlink: |
| 534 | * |
| 535 | * nlink relative to the upper inode - "U[+-]NUM" |
| 536 | * nlink relative to the lower inode - "L[+-]NUM" |
| 537 | */ |
| 538 | |
| 539 | static int ovl_set_nlink_common(struct dentry *dentry, |
| 540 | struct dentry *realdentry, const char *format) |
| 541 | { |
| 542 | struct inode *inode = d_inode(dentry); |
| 543 | struct inode *realinode = d_inode(realdentry); |
| 544 | char buf[13]; |
| 545 | int len; |
| 546 | |
| 547 | len = snprintf(buf, sizeof(buf), format, |
| 548 | (int) (inode->i_nlink - realinode->i_nlink)); |
| 549 | |
Miklos Szeredi | 6787341 | 2017-07-27 21:54:05 +0200 | [diff] [blame] | 550 | if (WARN_ON(len >= sizeof(buf))) |
| 551 | return -EIO; |
| 552 | |
Amir Goldstein | 5f8415d | 2017-06-20 15:35:14 +0300 | [diff] [blame] | 553 | return ovl_do_setxattr(ovl_dentry_upper(dentry), |
| 554 | OVL_XATTR_NLINK, buf, len, 0); |
| 555 | } |
| 556 | |
| 557 | int ovl_set_nlink_upper(struct dentry *dentry) |
| 558 | { |
| 559 | return ovl_set_nlink_common(dentry, ovl_dentry_upper(dentry), "U%+i"); |
| 560 | } |
| 561 | |
| 562 | int ovl_set_nlink_lower(struct dentry *dentry) |
| 563 | { |
| 564 | return ovl_set_nlink_common(dentry, ovl_dentry_lower(dentry), "L%+i"); |
| 565 | } |
| 566 | |
Amir Goldstein | caf70cb | 2017-06-21 13:46:12 +0300 | [diff] [blame] | 567 | unsigned int ovl_get_nlink(struct dentry *lowerdentry, |
| 568 | struct dentry *upperdentry, |
| 569 | unsigned int fallback) |
Amir Goldstein | 5f8415d | 2017-06-20 15:35:14 +0300 | [diff] [blame] | 570 | { |
| 571 | int nlink_diff; |
| 572 | int nlink; |
| 573 | char buf[13]; |
| 574 | int err; |
| 575 | |
| 576 | if (!lowerdentry || !upperdentry || d_inode(lowerdentry)->i_nlink == 1) |
| 577 | return fallback; |
| 578 | |
| 579 | err = vfs_getxattr(upperdentry, OVL_XATTR_NLINK, &buf, sizeof(buf) - 1); |
| 580 | if (err < 0) |
| 581 | goto fail; |
| 582 | |
| 583 | buf[err] = '\0'; |
| 584 | if ((buf[0] != 'L' && buf[0] != 'U') || |
| 585 | (buf[1] != '+' && buf[1] != '-')) |
| 586 | goto fail; |
| 587 | |
| 588 | err = kstrtoint(buf + 1, 10, &nlink_diff); |
| 589 | if (err < 0) |
| 590 | goto fail; |
| 591 | |
| 592 | nlink = d_inode(buf[0] == 'L' ? lowerdentry : upperdentry)->i_nlink; |
| 593 | nlink += nlink_diff; |
| 594 | |
| 595 | if (nlink <= 0) |
| 596 | goto fail; |
| 597 | |
| 598 | return nlink; |
| 599 | |
| 600 | fail: |
| 601 | pr_warn_ratelimited("overlayfs: failed to get index nlink (%pd2, err=%i)\n", |
| 602 | upperdentry, err); |
| 603 | return fallback; |
| 604 | } |
| 605 | |
Miklos Szeredi | ca4c8a3 | 2016-12-16 11:02:55 +0100 | [diff] [blame] | 606 | struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev) |
Miklos Szeredi | 51f7e52 | 2016-07-29 12:05:24 +0200 | [diff] [blame] | 607 | { |
| 608 | struct inode *inode; |
| 609 | |
| 610 | inode = new_inode(sb); |
| 611 | if (inode) |
Amir Goldstein | 695b46e | 2018-03-15 23:39:01 +0200 | [diff] [blame] | 612 | ovl_fill_inode(inode, mode, rdev, 0); |
Miklos Szeredi | 51f7e52 | 2016-07-29 12:05:24 +0200 | [diff] [blame] | 613 | |
| 614 | return inode; |
| 615 | } |
| 616 | |
| 617 | static int ovl_inode_test(struct inode *inode, void *data) |
| 618 | { |
Miklos Szeredi | 25b7713 | 2017-07-04 22:03:16 +0200 | [diff] [blame] | 619 | return inode->i_private == data; |
Miklos Szeredi | 51f7e52 | 2016-07-29 12:05:24 +0200 | [diff] [blame] | 620 | } |
| 621 | |
| 622 | static int ovl_inode_set(struct inode *inode, void *data) |
| 623 | { |
Miklos Szeredi | 25b7713 | 2017-07-04 22:03:16 +0200 | [diff] [blame] | 624 | inode->i_private = data; |
Miklos Szeredi | 51f7e52 | 2016-07-29 12:05:24 +0200 | [diff] [blame] | 625 | return 0; |
| 626 | } |
| 627 | |
Miklos Szeredi | b9ac5c27 | 2017-07-04 22:03:17 +0200 | [diff] [blame] | 628 | static bool ovl_verify_inode(struct inode *inode, struct dentry *lowerdentry, |
Amir Goldstein | 4b91c30 | 2018-01-18 16:39:13 +0200 | [diff] [blame] | 629 | struct dentry *upperdentry, bool strict) |
Miklos Szeredi | b9ac5c27 | 2017-07-04 22:03:17 +0200 | [diff] [blame] | 630 | { |
Amir Goldstein | 4b91c30 | 2018-01-18 16:39:13 +0200 | [diff] [blame] | 631 | /* |
| 632 | * For directories, @strict verify from lookup path performs consistency |
| 633 | * checks, so NULL lower/upper in dentry must match NULL lower/upper in |
| 634 | * inode. Non @strict verify from NFS handle decode path passes NULL for |
| 635 | * 'unknown' lower/upper. |
| 636 | */ |
| 637 | if (S_ISDIR(inode->i_mode) && strict) { |
Amir Goldstein | 31747ed | 2018-01-14 18:35:40 +0200 | [diff] [blame] | 638 | /* Real lower dir moved to upper layer under us? */ |
| 639 | if (!lowerdentry && ovl_inode_lower(inode)) |
| 640 | return false; |
| 641 | |
| 642 | /* Lookup of an uncovered redirect origin? */ |
| 643 | if (!upperdentry && ovl_inode_upper(inode)) |
| 644 | return false; |
| 645 | } |
| 646 | |
Amir Goldstein | 939ae4e | 2017-09-11 16:30:15 +0300 | [diff] [blame] | 647 | /* |
| 648 | * Allow non-NULL lower inode in ovl_inode even if lowerdentry is NULL. |
| 649 | * This happens when finding a copied up overlay inode for a renamed |
| 650 | * or hardlinked overlay dentry and lower dentry cannot be followed |
| 651 | * by origin because lower fs does not support file handles. |
| 652 | */ |
| 653 | if (lowerdentry && ovl_inode_lower(inode) != d_inode(lowerdentry)) |
Miklos Szeredi | b9ac5c27 | 2017-07-04 22:03:17 +0200 | [diff] [blame] | 654 | return false; |
| 655 | |
| 656 | /* |
| 657 | * Allow non-NULL __upperdentry in inode even if upperdentry is NULL. |
| 658 | * This happens when finding a lower alias for a copied up hard link. |
| 659 | */ |
| 660 | if (upperdentry && ovl_inode_upper(inode) != d_inode(upperdentry)) |
| 661 | return false; |
| 662 | |
| 663 | return true; |
| 664 | } |
| 665 | |
Amir Goldstein | 4b91c30 | 2018-01-18 16:39:13 +0200 | [diff] [blame] | 666 | struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real, |
| 667 | bool is_upper) |
Amir Goldstein | 9436a1a | 2017-12-24 18:28:04 +0200 | [diff] [blame] | 668 | { |
Amir Goldstein | 4b91c30 | 2018-01-18 16:39:13 +0200 | [diff] [blame] | 669 | struct inode *inode, *key = d_inode(real); |
Amir Goldstein | 9436a1a | 2017-12-24 18:28:04 +0200 | [diff] [blame] | 670 | |
| 671 | inode = ilookup5(sb, (unsigned long) key, ovl_inode_test, key); |
| 672 | if (!inode) |
| 673 | return NULL; |
| 674 | |
Amir Goldstein | 4b91c30 | 2018-01-18 16:39:13 +0200 | [diff] [blame] | 675 | if (!ovl_verify_inode(inode, is_upper ? NULL : real, |
| 676 | is_upper ? real : NULL, false)) { |
Amir Goldstein | 9436a1a | 2017-12-24 18:28:04 +0200 | [diff] [blame] | 677 | iput(inode); |
| 678 | return ERR_PTR(-ESTALE); |
| 679 | } |
| 680 | |
| 681 | return inode; |
| 682 | } |
| 683 | |
Amir Goldstein | 764baba | 2018-02-04 15:35:09 +0200 | [diff] [blame] | 684 | /* |
| 685 | * Does overlay inode need to be hashed by lower inode? |
| 686 | */ |
| 687 | static bool ovl_hash_bylower(struct super_block *sb, struct dentry *upper, |
| 688 | struct dentry *lower, struct dentry *index) |
| 689 | { |
| 690 | struct ovl_fs *ofs = sb->s_fs_info; |
| 691 | |
| 692 | /* No, if pure upper */ |
| 693 | if (!lower) |
| 694 | return false; |
| 695 | |
| 696 | /* Yes, if already indexed */ |
| 697 | if (index) |
| 698 | return true; |
| 699 | |
| 700 | /* Yes, if won't be copied up */ |
| 701 | if (!ofs->upper_mnt) |
| 702 | return true; |
| 703 | |
| 704 | /* No, if lower hardlink is or will be broken on copy up */ |
| 705 | if ((upper || !ovl_indexdir(sb)) && |
| 706 | !d_is_dir(lower) && d_inode(lower)->i_nlink > 1) |
| 707 | return false; |
| 708 | |
| 709 | /* No, if non-indexed upper with NFS export */ |
| 710 | if (sb->s_export_op && upper) |
| 711 | return false; |
| 712 | |
| 713 | /* Otherwise, hash by lower inode for fsnotify */ |
| 714 | return true; |
| 715 | } |
| 716 | |
Amir Goldstein | 0aceb53 | 2017-12-12 23:43:16 +0200 | [diff] [blame] | 717 | struct inode *ovl_get_inode(struct super_block *sb, struct dentry *upperdentry, |
| 718 | struct dentry *lowerdentry, struct dentry *index, |
| 719 | unsigned int numlower) |
Miklos Szeredi | 51f7e52 | 2016-07-29 12:05:24 +0200 | [diff] [blame] | 720 | { |
Miklos Szeredi | 09d8b58 | 2017-07-04 22:03:16 +0200 | [diff] [blame] | 721 | struct inode *realinode = upperdentry ? d_inode(upperdentry) : NULL; |
Miklos Szeredi | 51f7e52 | 2016-07-29 12:05:24 +0200 | [diff] [blame] | 722 | struct inode *inode; |
Amir Goldstein | 764baba | 2018-02-04 15:35:09 +0200 | [diff] [blame] | 723 | bool bylower = ovl_hash_bylower(sb, upperdentry, lowerdentry, index); |
Amir Goldstein | 31747ed | 2018-01-14 18:35:40 +0200 | [diff] [blame] | 724 | bool is_dir; |
Amir Goldstein | 695b46e | 2018-03-15 23:39:01 +0200 | [diff] [blame] | 725 | unsigned long ino = 0; |
Amir Goldstein | 6eaf011 | 2017-10-12 19:03:04 +0300 | [diff] [blame] | 726 | |
Miklos Szeredi | 09d8b58 | 2017-07-04 22:03:16 +0200 | [diff] [blame] | 727 | if (!realinode) |
| 728 | realinode = d_inode(lowerdentry); |
| 729 | |
Amir Goldstein | 6eaf011 | 2017-10-12 19:03:04 +0300 | [diff] [blame] | 730 | /* |
Amir Goldstein | 764baba | 2018-02-04 15:35:09 +0200 | [diff] [blame] | 731 | * Copy up origin (lower) may exist for non-indexed upper, but we must |
| 732 | * not use lower as hash key if this is a broken hardlink. |
Amir Goldstein | 6eaf011 | 2017-10-12 19:03:04 +0300 | [diff] [blame] | 733 | */ |
Amir Goldstein | 31747ed | 2018-01-14 18:35:40 +0200 | [diff] [blame] | 734 | is_dir = S_ISDIR(realinode->i_mode); |
Amir Goldstein | 764baba | 2018-02-04 15:35:09 +0200 | [diff] [blame] | 735 | if (upperdentry || bylower) { |
| 736 | struct inode *key = d_inode(bylower ? lowerdentry : |
| 737 | upperdentry); |
Amir Goldstein | 31747ed | 2018-01-14 18:35:40 +0200 | [diff] [blame] | 738 | unsigned int nlink = is_dir ? 1 : realinode->i_nlink; |
Miklos Szeredi | b9ac5c27 | 2017-07-04 22:03:17 +0200 | [diff] [blame] | 739 | |
Amir Goldstein | 0aceb53 | 2017-12-12 23:43:16 +0200 | [diff] [blame] | 740 | inode = iget5_locked(sb, (unsigned long) key, |
Miklos Szeredi | b9ac5c27 | 2017-07-04 22:03:17 +0200 | [diff] [blame] | 741 | ovl_inode_test, ovl_inode_set, key); |
Miklos Szeredi | 09d8b58 | 2017-07-04 22:03:16 +0200 | [diff] [blame] | 742 | if (!inode) |
Miklos Szeredi | b9ac5c27 | 2017-07-04 22:03:17 +0200 | [diff] [blame] | 743 | goto out_nomem; |
Miklos Szeredi | 09d8b58 | 2017-07-04 22:03:16 +0200 | [diff] [blame] | 744 | if (!(inode->i_state & I_NEW)) { |
Miklos Szeredi | b9ac5c27 | 2017-07-04 22:03:17 +0200 | [diff] [blame] | 745 | /* |
| 746 | * Verify that the underlying files stored in the inode |
| 747 | * match those in the dentry. |
| 748 | */ |
Amir Goldstein | 4b91c30 | 2018-01-18 16:39:13 +0200 | [diff] [blame] | 749 | if (!ovl_verify_inode(inode, lowerdentry, upperdentry, |
| 750 | true)) { |
Miklos Szeredi | b9ac5c27 | 2017-07-04 22:03:17 +0200 | [diff] [blame] | 751 | iput(inode); |
| 752 | inode = ERR_PTR(-ESTALE); |
| 753 | goto out; |
| 754 | } |
| 755 | |
Miklos Szeredi | 09d8b58 | 2017-07-04 22:03:16 +0200 | [diff] [blame] | 756 | dput(upperdentry); |
| 757 | goto out; |
| 758 | } |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 759 | |
Amir Goldstein | 31747ed | 2018-01-14 18:35:40 +0200 | [diff] [blame] | 760 | /* Recalculate nlink for non-dir due to indexing */ |
| 761 | if (!is_dir) |
| 762 | nlink = ovl_get_nlink(lowerdentry, upperdentry, nlink); |
Amir Goldstein | 5f8415d | 2017-06-20 15:35:14 +0300 | [diff] [blame] | 763 | set_nlink(inode, nlink); |
Amir Goldstein | 695b46e | 2018-03-15 23:39:01 +0200 | [diff] [blame] | 764 | ino = key->i_ino; |
Miklos Szeredi | e6d2ebd | 2017-07-04 22:03:16 +0200 | [diff] [blame] | 765 | } else { |
Amir Goldstein | 764baba | 2018-02-04 15:35:09 +0200 | [diff] [blame] | 766 | /* Lower hardlink that will be broken on copy up */ |
Amir Goldstein | 0aceb53 | 2017-12-12 23:43:16 +0200 | [diff] [blame] | 767 | inode = new_inode(sb); |
Miklos Szeredi | e6d2ebd | 2017-07-04 22:03:16 +0200 | [diff] [blame] | 768 | if (!inode) |
Miklos Szeredi | b9ac5c27 | 2017-07-04 22:03:17 +0200 | [diff] [blame] | 769 | goto out_nomem; |
Miklos Szeredi | e6d2ebd | 2017-07-04 22:03:16 +0200 | [diff] [blame] | 770 | } |
Amir Goldstein | 695b46e | 2018-03-15 23:39:01 +0200 | [diff] [blame] | 771 | ovl_fill_inode(inode, realinode->i_mode, realinode->i_rdev, ino); |
Miklos Szeredi | 09d8b58 | 2017-07-04 22:03:16 +0200 | [diff] [blame] | 772 | ovl_inode_init(inode, upperdentry, lowerdentry); |
Miklos Szeredi | 13c7207 | 2017-07-04 22:03:16 +0200 | [diff] [blame] | 773 | |
| 774 | if (upperdentry && ovl_is_impuredir(upperdentry)) |
| 775 | ovl_set_flag(OVL_IMPURE, inode); |
| 776 | |
Vivek Goyal | 0471a9c | 2018-03-20 16:35:40 -0400 | [diff] [blame] | 777 | if (index) |
| 778 | ovl_set_flag(OVL_INDEX, inode); |
| 779 | |
Amir Goldstein | b79e05a | 2017-06-25 16:37:17 +0300 | [diff] [blame] | 780 | /* Check for non-merge dir that may have whiteouts */ |
Amir Goldstein | 31747ed | 2018-01-14 18:35:40 +0200 | [diff] [blame] | 781 | if (is_dir) { |
Amir Goldstein | 0aceb53 | 2017-12-12 23:43:16 +0200 | [diff] [blame] | 782 | if (((upperdentry && lowerdentry) || numlower > 1) || |
Amir Goldstein | b79e05a | 2017-06-25 16:37:17 +0300 | [diff] [blame] | 783 | ovl_check_origin_xattr(upperdentry ?: lowerdentry)) { |
| 784 | ovl_set_flag(OVL_WHITEOUTS, inode); |
| 785 | } |
| 786 | } |
| 787 | |
Miklos Szeredi | e6d2ebd | 2017-07-04 22:03:16 +0200 | [diff] [blame] | 788 | if (inode->i_state & I_NEW) |
| 789 | unlock_new_inode(inode); |
| 790 | out: |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 791 | return inode; |
Miklos Szeredi | b9ac5c27 | 2017-07-04 22:03:17 +0200 | [diff] [blame] | 792 | |
| 793 | out_nomem: |
| 794 | inode = ERR_PTR(-ENOMEM); |
| 795 | goto out; |
Miklos Szeredi | e9be9d5 | 2014-10-24 00:14:38 +0200 | [diff] [blame] | 796 | } |