Commit | Line | Data |
---|---|---|
457c8996 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
1da177e4 LT |
2 | /* |
3 | File: fs/xattr.c | |
4 | ||
5 | Extended attribute handling. | |
6 | ||
7 | Copyright (C) 2001 by Andreas Gruenbacher <a.gruenbacher@computer.org> | |
8 | Copyright (C) 2001 SGI - Silicon Graphics, Inc <linux-xfs@oss.sgi.com> | |
9 | Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com> | |
10 | */ | |
11 | #include <linux/fs.h> | |
12 | #include <linux/slab.h> | |
1da177e4 LT |
13 | #include <linux/file.h> |
14 | #include <linux/xattr.h> | |
18f335af | 15 | #include <linux/mount.h> |
1da177e4 LT |
16 | #include <linux/namei.h> |
17 | #include <linux/security.h> | |
c7b87de2 | 18 | #include <linux/evm.h> |
1da177e4 | 19 | #include <linux/syscalls.h> |
630d9c47 | 20 | #include <linux/export.h> |
0eeca283 | 21 | #include <linux/fsnotify.h> |
73241ccc | 22 | #include <linux/audit.h> |
0d08d7b7 | 23 | #include <linux/vmalloc.h> |
2f6f0654 | 24 | #include <linux/posix_acl_xattr.h> |
1da177e4 | 25 | |
7c0f6ba6 | 26 | #include <linux/uaccess.h> |
5be196e5 | 27 | |
1a91794c SR |
28 | #include "internal.h" |
29 | ||
b6ba1177 AG |
30 | static const char * |
31 | strcmp_prefix(const char *a, const char *a_prefix) | |
32 | { | |
33 | while (*a_prefix && *a == *a_prefix) { | |
34 | a++; | |
35 | a_prefix++; | |
36 | } | |
37 | return *a_prefix ? NULL : a; | |
38 | } | |
39 | ||
40 | /* | |
41 | * In order to implement different sets of xattr operations for each xattr | |
6c6ef9f2 AG |
42 | * prefix, a filesystem should create a null-terminated array of struct |
43 | * xattr_handler (one for each prefix) and hang a pointer to it off of the | |
44 | * s_xattr field of the superblock. | |
b6ba1177 AG |
45 | */ |
46 | #define for_each_xattr_handler(handlers, handler) \ | |
47 | if (handlers) \ | |
48 | for ((handler) = *(handlers)++; \ | |
49 | (handler) != NULL; \ | |
50 | (handler) = *(handlers)++) | |
51 | ||
52 | /* | |
53 | * Find the xattr_handler with the matching prefix. | |
54 | */ | |
55 | static const struct xattr_handler * | |
d0a5b995 | 56 | xattr_resolve_name(struct inode *inode, const char **name) |
b6ba1177 | 57 | { |
d0a5b995 | 58 | const struct xattr_handler **handlers = inode->i_sb->s_xattr; |
b6ba1177 AG |
59 | const struct xattr_handler *handler; |
60 | ||
5f6e59ae AG |
61 | if (!(inode->i_opflags & IOP_XATTR)) { |
62 | if (unlikely(is_bad_inode(inode))) | |
63 | return ERR_PTR(-EIO); | |
d0a5b995 | 64 | return ERR_PTR(-EOPNOTSUPP); |
5f6e59ae | 65 | } |
b6ba1177 AG |
66 | for_each_xattr_handler(handlers, handler) { |
67 | const char *n; | |
68 | ||
69 | n = strcmp_prefix(*name, xattr_prefix(handler)); | |
70 | if (n) { | |
71 | if (!handler->prefix ^ !*n) { | |
72 | if (*n) | |
73 | continue; | |
74 | return ERR_PTR(-EINVAL); | |
75 | } | |
76 | *name = n; | |
77 | return handler; | |
78 | } | |
79 | } | |
80 | return ERR_PTR(-EOPNOTSUPP); | |
81 | } | |
82 | ||
56851bc9 CB |
83 | /** |
84 | * may_write_xattr - check whether inode allows writing xattr | |
85 | * @mnt_userns: User namespace of the mount the inode was found from | |
86 | * @inode: the inode on which to set an xattr | |
87 | * | |
88 | * Check whether the inode allows writing xattrs. Specifically, we can never | |
89 | * set or remove an extended attribute on a read-only filesystem or on an | |
90 | * immutable / append-only inode. | |
91 | * | |
92 | * We also need to ensure that the inode has a mapping in the mount to | |
93 | * not risk writing back invalid i_{g,u}id values. | |
94 | * | |
95 | * Return: On success zero is returned. On error a negative errno is returned. | |
96 | */ | |
97 | int may_write_xattr(struct user_namespace *mnt_userns, struct inode *inode) | |
98 | { | |
99 | if (IS_IMMUTABLE(inode)) | |
100 | return -EPERM; | |
101 | if (IS_APPEND(inode)) | |
102 | return -EPERM; | |
103 | if (HAS_UNMAPPED_ID(mnt_userns, inode)) | |
104 | return -EPERM; | |
105 | return 0; | |
106 | } | |
107 | ||
e0ad7b07 | 108 | /* |
109 | * Check permissions for extended attribute access. This is a bit complicated | |
110 | * because different namespaces have very different rules. | |
111 | */ | |
112 | static int | |
c7c7a1a1 TA |
113 | xattr_permission(struct user_namespace *mnt_userns, struct inode *inode, |
114 | const char *name, int mask) | |
e0ad7b07 | 115 | { |
e0ad7b07 | 116 | if (mask & MAY_WRITE) { |
56851bc9 CB |
117 | int ret; |
118 | ||
119 | ret = may_write_xattr(mnt_userns, inode); | |
120 | if (ret) | |
121 | return ret; | |
e0ad7b07 | 122 | } |
123 | ||
124 | /* | |
125 | * No restriction for security.* and system.* from the VFS. Decision | |
126 | * on these is left to the underlying filesystem / security module. | |
127 | */ | |
128 | if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) || | |
129 | !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
130 | return 0; | |
131 | ||
132 | /* | |
55b23bde | 133 | * The trusted.* namespace can only be accessed by privileged users. |
e0ad7b07 | 134 | */ |
55b23bde AG |
135 | if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) { |
136 | if (!capable(CAP_SYS_ADMIN)) | |
137 | return (mask & MAY_WRITE) ? -EPERM : -ENODATA; | |
138 | return 0; | |
139 | } | |
e0ad7b07 | 140 | |
55b23bde AG |
141 | /* |
142 | * In the user.* namespace, only regular files and directories can have | |
f1f2d871 | 143 | * extended attributes. For sticky directories, only the owner and |
55b23bde | 144 | * privileged users can write attributes. |
f1f2d871 | 145 | */ |
e0ad7b07 | 146 | if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) { |
f1f2d871 | 147 | if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode)) |
55b23bde | 148 | return (mask & MAY_WRITE) ? -EPERM : -ENODATA; |
f1f2d871 | 149 | if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) && |
21cb47be | 150 | (mask & MAY_WRITE) && |
c7c7a1a1 | 151 | !inode_owner_or_capable(mnt_userns, inode)) |
e0ad7b07 | 152 | return -EPERM; |
153 | } | |
154 | ||
c7c7a1a1 | 155 | return inode_permission(mnt_userns, inode, mask); |
e0ad7b07 | 156 | } |
157 | ||
cab8d289 FL |
158 | /* |
159 | * Look for any handler that deals with the specified namespace. | |
160 | */ | |
161 | int | |
162 | xattr_supported_namespace(struct inode *inode, const char *prefix) | |
163 | { | |
164 | const struct xattr_handler **handlers = inode->i_sb->s_xattr; | |
165 | const struct xattr_handler *handler; | |
166 | size_t preflen; | |
167 | ||
168 | if (!(inode->i_opflags & IOP_XATTR)) { | |
169 | if (unlikely(is_bad_inode(inode))) | |
170 | return -EIO; | |
171 | return -EOPNOTSUPP; | |
172 | } | |
173 | ||
174 | preflen = strlen(prefix); | |
175 | ||
176 | for_each_xattr_handler(handlers, handler) { | |
177 | if (!strncmp(xattr_prefix(handler), prefix, preflen)) | |
178 | return 0; | |
179 | } | |
180 | ||
181 | return -EOPNOTSUPP; | |
182 | } | |
183 | EXPORT_SYMBOL(xattr_supported_namespace); | |
184 | ||
5d6c3191 | 185 | int |
c7c7a1a1 TA |
186 | __vfs_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry, |
187 | struct inode *inode, const char *name, const void *value, | |
188 | size_t size, int flags) | |
5d6c3191 | 189 | { |
6c6ef9f2 AG |
190 | const struct xattr_handler *handler; |
191 | ||
318e6685 CB |
192 | if (is_posix_acl_xattr(name)) |
193 | return -EOPNOTSUPP; | |
194 | ||
6c6ef9f2 AG |
195 | handler = xattr_resolve_name(inode, &name); |
196 | if (IS_ERR(handler)) | |
197 | return PTR_ERR(handler); | |
198 | if (!handler->set) | |
5d6c3191 | 199 | return -EOPNOTSUPP; |
6c6ef9f2 AG |
200 | if (size == 0) |
201 | value = ""; /* empty EA, do not remove */ | |
c7c7a1a1 | 202 | return handler->set(handler, mnt_userns, dentry, inode, name, value, |
e65ce2a5 | 203 | size, flags); |
5d6c3191 AG |
204 | } |
205 | EXPORT_SYMBOL(__vfs_setxattr); | |
206 | ||
b1ab7e4b DQ |
207 | /** |
208 | * __vfs_setxattr_noperm - perform setxattr operation without performing | |
209 | * permission checks. | |
210 | * | |
6961fed4 RD |
211 | * @mnt_userns: user namespace of the mount the inode was found from |
212 | * @dentry: object to perform setxattr on | |
213 | * @name: xattr name to set | |
214 | * @value: value to set @name to | |
215 | * @size: size of @value | |
216 | * @flags: flags to pass into filesystem operations | |
b1ab7e4b DQ |
217 | * |
218 | * returns the result of the internal setxattr or setsecurity operations. | |
219 | * | |
220 | * This function requires the caller to lock the inode's i_mutex before it | |
221 | * is executed. It also assumes that the caller will make the appropriate | |
222 | * permission checks. | |
223 | */ | |
c7c7a1a1 TA |
224 | int __vfs_setxattr_noperm(struct user_namespace *mnt_userns, |
225 | struct dentry *dentry, const char *name, | |
226 | const void *value, size_t size, int flags) | |
5be196e5 CH |
227 | { |
228 | struct inode *inode = dentry->d_inode; | |
4a590153 | 229 | int error = -EAGAIN; |
69b45732 AK |
230 | int issec = !strncmp(name, XATTR_SECURITY_PREFIX, |
231 | XATTR_SECURITY_PREFIX_LEN); | |
e0ad7b07 | 232 | |
69b45732 AK |
233 | if (issec) |
234 | inode->i_flags &= ~S_NOSEC; | |
6c6ef9f2 | 235 | if (inode->i_opflags & IOP_XATTR) { |
c7c7a1a1 TA |
236 | error = __vfs_setxattr(mnt_userns, dentry, inode, name, value, |
237 | size, flags); | |
5be196e5 CH |
238 | if (!error) { |
239 | fsnotify_xattr(dentry); | |
240 | security_inode_post_setxattr(dentry, name, value, | |
241 | size, flags); | |
242 | } | |
4a590153 | 243 | } else { |
5f6e59ae AG |
244 | if (unlikely(is_bad_inode(inode))) |
245 | return -EIO; | |
4a590153 AG |
246 | } |
247 | if (error == -EAGAIN) { | |
248 | error = -EOPNOTSUPP; | |
249 | ||
250 | if (issec) { | |
251 | const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; | |
252 | ||
253 | error = security_inode_setsecurity(inode, suffix, value, | |
254 | size, flags); | |
255 | if (!error) | |
256 | fsnotify_xattr(dentry); | |
257 | } | |
5be196e5 | 258 | } |
b1ab7e4b DQ |
259 | |
260 | return error; | |
261 | } | |
262 | ||
08b5d501 | 263 | /** |
da5c1c0b | 264 | * __vfs_setxattr_locked - set an extended attribute while holding the inode |
08b5d501 FL |
265 | * lock |
266 | * | |
6961fed4 | 267 | * @mnt_userns: user namespace of the mount of the target inode |
da5c1c0b RD |
268 | * @dentry: object to perform setxattr on |
269 | * @name: xattr name to set | |
270 | * @value: value to set @name to | |
271 | * @size: size of @value | |
272 | * @flags: flags to pass into filesystem operations | |
273 | * @delegated_inode: on return, will contain an inode pointer that | |
08b5d501 FL |
274 | * a delegation was broken on, NULL if none. |
275 | */ | |
b1ab7e4b | 276 | int |
c7c7a1a1 TA |
277 | __vfs_setxattr_locked(struct user_namespace *mnt_userns, struct dentry *dentry, |
278 | const char *name, const void *value, size_t size, | |
279 | int flags, struct inode **delegated_inode) | |
b1ab7e4b DQ |
280 | { |
281 | struct inode *inode = dentry->d_inode; | |
282 | int error; | |
283 | ||
c7c7a1a1 | 284 | error = xattr_permission(mnt_userns, inode, name, MAY_WRITE); |
b1ab7e4b DQ |
285 | if (error) |
286 | return error; | |
287 | ||
71bc356f CB |
288 | error = security_inode_setxattr(mnt_userns, dentry, name, value, size, |
289 | flags); | |
b1ab7e4b DQ |
290 | if (error) |
291 | goto out; | |
292 | ||
08b5d501 FL |
293 | error = try_break_deleg(inode, delegated_inode); |
294 | if (error) | |
295 | goto out; | |
296 | ||
c7c7a1a1 TA |
297 | error = __vfs_setxattr_noperm(mnt_userns, dentry, name, value, |
298 | size, flags); | |
b1ab7e4b | 299 | |
5be196e5 | 300 | out: |
08b5d501 FL |
301 | return error; |
302 | } | |
303 | EXPORT_SYMBOL_GPL(__vfs_setxattr_locked); | |
304 | ||
305 | int | |
c7c7a1a1 | 306 | vfs_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry, |
6344e669 | 307 | const char *name, const void *value, size_t size, int flags) |
08b5d501 FL |
308 | { |
309 | struct inode *inode = dentry->d_inode; | |
310 | struct inode *delegated_inode = NULL; | |
7c03e2cd | 311 | const void *orig_value = value; |
08b5d501 FL |
312 | int error; |
313 | ||
7c03e2cd | 314 | if (size && strcmp(name, XATTR_NAME_CAPS) == 0) { |
6344e669 | 315 | error = cap_convert_nscap(mnt_userns, dentry, &value, size); |
7c03e2cd MS |
316 | if (error < 0) |
317 | return error; | |
318 | size = error; | |
319 | } | |
320 | ||
08b5d501 FL |
321 | retry_deleg: |
322 | inode_lock(inode); | |
c7c7a1a1 TA |
323 | error = __vfs_setxattr_locked(mnt_userns, dentry, name, value, size, |
324 | flags, &delegated_inode); | |
5955102c | 325 | inode_unlock(inode); |
08b5d501 FL |
326 | |
327 | if (delegated_inode) { | |
328 | error = break_deleg_wait(&delegated_inode); | |
329 | if (!error) | |
330 | goto retry_deleg; | |
331 | } | |
7c03e2cd MS |
332 | if (value != orig_value) |
333 | kfree(value); | |
334 | ||
5be196e5 CH |
335 | return error; |
336 | } | |
337 | EXPORT_SYMBOL_GPL(vfs_setxattr); | |
338 | ||
2220c5b0 | 339 | static ssize_t |
71bc356f CB |
340 | xattr_getsecurity(struct user_namespace *mnt_userns, struct inode *inode, |
341 | const char *name, void *value, size_t size) | |
42492594 DQ |
342 | { |
343 | void *buffer = NULL; | |
344 | ssize_t len; | |
345 | ||
346 | if (!value || !size) { | |
71bc356f CB |
347 | len = security_inode_getsecurity(mnt_userns, inode, name, |
348 | &buffer, false); | |
42492594 DQ |
349 | goto out_noalloc; |
350 | } | |
351 | ||
71bc356f CB |
352 | len = security_inode_getsecurity(mnt_userns, inode, name, &buffer, |
353 | true); | |
42492594 DQ |
354 | if (len < 0) |
355 | return len; | |
356 | if (size < len) { | |
357 | len = -ERANGE; | |
358 | goto out; | |
359 | } | |
360 | memcpy(value, buffer, len); | |
361 | out: | |
57e7ba04 | 362 | kfree(buffer); |
42492594 DQ |
363 | out_noalloc: |
364 | return len; | |
365 | } | |
42492594 | 366 | |
1601fbad MZ |
367 | /* |
368 | * vfs_getxattr_alloc - allocate memory, if necessary, before calling getxattr | |
369 | * | |
370 | * Allocate memory, if not already allocated, or re-allocate correct size, | |
371 | * before retrieving the extended attribute. | |
372 | * | |
373 | * Returns the result of alloc, if failed, or the getxattr operation. | |
374 | */ | |
375 | ssize_t | |
c7c7a1a1 TA |
376 | vfs_getxattr_alloc(struct user_namespace *mnt_userns, struct dentry *dentry, |
377 | const char *name, char **xattr_value, size_t xattr_size, | |
378 | gfp_t flags) | |
1601fbad | 379 | { |
6c6ef9f2 | 380 | const struct xattr_handler *handler; |
1601fbad MZ |
381 | struct inode *inode = dentry->d_inode; |
382 | char *value = *xattr_value; | |
383 | int error; | |
384 | ||
c7c7a1a1 | 385 | error = xattr_permission(mnt_userns, inode, name, MAY_READ); |
1601fbad MZ |
386 | if (error) |
387 | return error; | |
388 | ||
6c6ef9f2 AG |
389 | handler = xattr_resolve_name(inode, &name); |
390 | if (IS_ERR(handler)) | |
391 | return PTR_ERR(handler); | |
392 | if (!handler->get) | |
1601fbad | 393 | return -EOPNOTSUPP; |
6c6ef9f2 | 394 | error = handler->get(handler, dentry, inode, name, NULL, 0); |
1601fbad MZ |
395 | if (error < 0) |
396 | return error; | |
397 | ||
398 | if (!value || (error > xattr_size)) { | |
399 | value = krealloc(*xattr_value, error + 1, flags); | |
400 | if (!value) | |
401 | return -ENOMEM; | |
402 | memset(value, 0, error + 1); | |
403 | } | |
404 | ||
6c6ef9f2 | 405 | error = handler->get(handler, dentry, inode, name, value, error); |
1601fbad MZ |
406 | *xattr_value = value; |
407 | return error; | |
408 | } | |
409 | ||
5d6c3191 AG |
410 | ssize_t |
411 | __vfs_getxattr(struct dentry *dentry, struct inode *inode, const char *name, | |
412 | void *value, size_t size) | |
413 | { | |
6c6ef9f2 AG |
414 | const struct xattr_handler *handler; |
415 | ||
318e6685 CB |
416 | if (is_posix_acl_xattr(name)) |
417 | return -EOPNOTSUPP; | |
418 | ||
6c6ef9f2 AG |
419 | handler = xattr_resolve_name(inode, &name); |
420 | if (IS_ERR(handler)) | |
421 | return PTR_ERR(handler); | |
422 | if (!handler->get) | |
5d6c3191 | 423 | return -EOPNOTSUPP; |
6c6ef9f2 | 424 | return handler->get(handler, dentry, inode, name, value, size); |
5d6c3191 AG |
425 | } |
426 | EXPORT_SYMBOL(__vfs_getxattr); | |
427 | ||
5be196e5 | 428 | ssize_t |
c7c7a1a1 TA |
429 | vfs_getxattr(struct user_namespace *mnt_userns, struct dentry *dentry, |
430 | const char *name, void *value, size_t size) | |
5be196e5 CH |
431 | { |
432 | struct inode *inode = dentry->d_inode; | |
433 | int error; | |
434 | ||
c7c7a1a1 | 435 | error = xattr_permission(mnt_userns, inode, name, MAY_READ); |
e0ad7b07 | 436 | if (error) |
437 | return error; | |
438 | ||
5be196e5 CH |
439 | error = security_inode_getxattr(dentry, name); |
440 | if (error) | |
441 | return error; | |
442 | ||
5be196e5 | 443 | if (!strncmp(name, XATTR_SECURITY_PREFIX, |
e0ad7b07 | 444 | XATTR_SECURITY_PREFIX_LEN)) { |
445 | const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; | |
71bc356f CB |
446 | int ret = xattr_getsecurity(mnt_userns, inode, suffix, value, |
447 | size); | |
5be196e5 CH |
448 | /* |
449 | * Only overwrite the return value if a security module | |
450 | * is actually active. | |
451 | */ | |
4bea5805 DQ |
452 | if (ret == -EOPNOTSUPP) |
453 | goto nolsm; | |
454 | return ret; | |
5be196e5 | 455 | } |
4bea5805 | 456 | nolsm: |
0a26bde2 | 457 | return __vfs_getxattr(dentry, inode, name, value, size); |
5be196e5 CH |
458 | } |
459 | EXPORT_SYMBOL_GPL(vfs_getxattr); | |
460 | ||
659564c8 | 461 | ssize_t |
bf3ee713 | 462 | vfs_listxattr(struct dentry *dentry, char *list, size_t size) |
659564c8 | 463 | { |
bf3ee713 | 464 | struct inode *inode = d_inode(dentry); |
659564c8 BN |
465 | ssize_t error; |
466 | ||
bf3ee713 | 467 | error = security_inode_listxattr(dentry); |
659564c8 BN |
468 | if (error) |
469 | return error; | |
bf3ee713 | 470 | if (inode->i_op->listxattr && (inode->i_opflags & IOP_XATTR)) { |
bf3ee713 | 471 | error = inode->i_op->listxattr(dentry, list, size); |
659564c8 | 472 | } else { |
bf3ee713 | 473 | error = security_inode_listsecurity(inode, list, size); |
659564c8 BN |
474 | if (size && error > size) |
475 | error = -ERANGE; | |
476 | } | |
477 | return error; | |
478 | } | |
479 | EXPORT_SYMBOL_GPL(vfs_listxattr); | |
480 | ||
5be196e5 | 481 | int |
c7c7a1a1 TA |
482 | __vfs_removexattr(struct user_namespace *mnt_userns, struct dentry *dentry, |
483 | const char *name) | |
5be196e5 | 484 | { |
6c6ef9f2 AG |
485 | struct inode *inode = d_inode(dentry); |
486 | const struct xattr_handler *handler; | |
5be196e5 | 487 | |
318e6685 CB |
488 | if (is_posix_acl_xattr(name)) |
489 | return -EOPNOTSUPP; | |
490 | ||
6c6ef9f2 AG |
491 | handler = xattr_resolve_name(inode, &name); |
492 | if (IS_ERR(handler)) | |
493 | return PTR_ERR(handler); | |
494 | if (!handler->set) | |
5be196e5 | 495 | return -EOPNOTSUPP; |
c7c7a1a1 TA |
496 | return handler->set(handler, mnt_userns, dentry, inode, name, NULL, 0, |
497 | XATTR_REPLACE); | |
5d6c3191 AG |
498 | } |
499 | EXPORT_SYMBOL(__vfs_removexattr); | |
500 | ||
08b5d501 | 501 | /** |
da5c1c0b | 502 | * __vfs_removexattr_locked - set an extended attribute while holding the inode |
08b5d501 FL |
503 | * lock |
504 | * | |
6961fed4 | 505 | * @mnt_userns: user namespace of the mount of the target inode |
da5c1c0b RD |
506 | * @dentry: object to perform setxattr on |
507 | * @name: name of xattr to remove | |
508 | * @delegated_inode: on return, will contain an inode pointer that | |
08b5d501 FL |
509 | * a delegation was broken on, NULL if none. |
510 | */ | |
5d6c3191 | 511 | int |
c7c7a1a1 TA |
512 | __vfs_removexattr_locked(struct user_namespace *mnt_userns, |
513 | struct dentry *dentry, const char *name, | |
514 | struct inode **delegated_inode) | |
5d6c3191 AG |
515 | { |
516 | struct inode *inode = dentry->d_inode; | |
517 | int error; | |
5be196e5 | 518 | |
c7c7a1a1 | 519 | error = xattr_permission(mnt_userns, inode, name, MAY_WRITE); |
e0ad7b07 | 520 | if (error) |
521 | return error; | |
522 | ||
71bc356f | 523 | error = security_inode_removexattr(mnt_userns, dentry, name); |
7c51bb00 DK |
524 | if (error) |
525 | goto out; | |
5be196e5 | 526 | |
08b5d501 FL |
527 | error = try_break_deleg(inode, delegated_inode); |
528 | if (error) | |
529 | goto out; | |
530 | ||
c7c7a1a1 | 531 | error = __vfs_removexattr(mnt_userns, dentry, name); |
5be196e5 | 532 | |
c7b87de2 | 533 | if (!error) { |
5be196e5 | 534 | fsnotify_xattr(dentry); |
c7b87de2 MZ |
535 | evm_inode_post_removexattr(dentry, name); |
536 | } | |
7c51bb00 DK |
537 | |
538 | out: | |
08b5d501 FL |
539 | return error; |
540 | } | |
541 | EXPORT_SYMBOL_GPL(__vfs_removexattr_locked); | |
542 | ||
543 | int | |
c7c7a1a1 TA |
544 | vfs_removexattr(struct user_namespace *mnt_userns, struct dentry *dentry, |
545 | const char *name) | |
08b5d501 FL |
546 | { |
547 | struct inode *inode = dentry->d_inode; | |
548 | struct inode *delegated_inode = NULL; | |
549 | int error; | |
550 | ||
551 | retry_deleg: | |
552 | inode_lock(inode); | |
c7c7a1a1 TA |
553 | error = __vfs_removexattr_locked(mnt_userns, dentry, |
554 | name, &delegated_inode); | |
5955102c | 555 | inode_unlock(inode); |
08b5d501 FL |
556 | |
557 | if (delegated_inode) { | |
558 | error = break_deleg_wait(&delegated_inode); | |
559 | if (!error) | |
560 | goto retry_deleg; | |
561 | } | |
562 | ||
5be196e5 CH |
563 | return error; |
564 | } | |
565 | EXPORT_SYMBOL_GPL(vfs_removexattr); | |
566 | ||
1da177e4 LT |
567 | /* |
568 | * Extended attribute SET operations | |
569 | */ | |
1a91794c SR |
570 | |
571 | int setxattr_copy(const char __user *name, struct xattr_ctx *ctx) | |
1da177e4 LT |
572 | { |
573 | int error; | |
1da177e4 | 574 | |
1a91794c | 575 | if (ctx->flags & ~(XATTR_CREATE|XATTR_REPLACE)) |
1da177e4 LT |
576 | return -EINVAL; |
577 | ||
1a91794c SR |
578 | error = strncpy_from_user(ctx->kname->name, name, |
579 | sizeof(ctx->kname->name)); | |
580 | if (error == 0 || error == sizeof(ctx->kname->name)) | |
581 | return -ERANGE; | |
1da177e4 LT |
582 | if (error < 0) |
583 | return error; | |
584 | ||
1a91794c SR |
585 | error = 0; |
586 | if (ctx->size) { | |
587 | if (ctx->size > XATTR_SIZE_MAX) | |
1da177e4 | 588 | return -E2BIG; |
1a91794c SR |
589 | |
590 | ctx->kvalue = vmemdup_user(ctx->cvalue, ctx->size); | |
591 | if (IS_ERR(ctx->kvalue)) { | |
592 | error = PTR_ERR(ctx->kvalue); | |
593 | ctx->kvalue = NULL; | |
44c82498 | 594 | } |
1da177e4 LT |
595 | } |
596 | ||
1a91794c SR |
597 | return error; |
598 | } | |
599 | ||
1a91794c SR |
600 | int do_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry, |
601 | struct xattr_ctx *ctx) | |
602 | { | |
318e6685 CB |
603 | if (is_posix_acl_xattr(ctx->kname->name)) |
604 | return do_set_acl(mnt_userns, dentry, ctx->kname->name, | |
605 | ctx->kvalue, ctx->size); | |
606 | ||
1a91794c SR |
607 | return vfs_setxattr(mnt_userns, dentry, ctx->kname->name, |
608 | ctx->kvalue, ctx->size, ctx->flags); | |
609 | } | |
610 | ||
611 | static long | |
612 | setxattr(struct user_namespace *mnt_userns, struct dentry *d, | |
613 | const char __user *name, const void __user *value, size_t size, | |
614 | int flags) | |
615 | { | |
616 | struct xattr_name kname; | |
617 | struct xattr_ctx ctx = { | |
618 | .cvalue = value, | |
619 | .kvalue = NULL, | |
620 | .size = size, | |
621 | .kname = &kname, | |
622 | .flags = flags, | |
623 | }; | |
624 | int error; | |
625 | ||
626 | error = setxattr_copy(name, &ctx); | |
627 | if (error) | |
628 | return error; | |
629 | ||
630 | error = do_setxattr(mnt_userns, d, &ctx); | |
0b2a6f23 | 631 | |
1a91794c | 632 | kvfree(ctx.kvalue); |
1da177e4 LT |
633 | return error; |
634 | } | |
635 | ||
8cc43116 EB |
636 | static int path_setxattr(const char __user *pathname, |
637 | const char __user *name, const void __user *value, | |
638 | size_t size, int flags, unsigned int lookup_flags) | |
1da177e4 | 639 | { |
2d8f3038 | 640 | struct path path; |
1da177e4 | 641 | int error; |
c7c7a1a1 | 642 | |
68f1bb8b JL |
643 | retry: |
644 | error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); | |
1da177e4 LT |
645 | if (error) |
646 | return error; | |
2d8f3038 | 647 | error = mnt_want_write(path.mnt); |
18f335af | 648 | if (!error) { |
c7c7a1a1 TA |
649 | error = setxattr(mnt_user_ns(path.mnt), path.dentry, name, |
650 | value, size, flags); | |
2d8f3038 | 651 | mnt_drop_write(path.mnt); |
18f335af | 652 | } |
2d8f3038 | 653 | path_put(&path); |
68f1bb8b JL |
654 | if (retry_estale(error, lookup_flags)) { |
655 | lookup_flags |= LOOKUP_REVAL; | |
656 | goto retry; | |
657 | } | |
1da177e4 LT |
658 | return error; |
659 | } | |
660 | ||
8cc43116 EB |
661 | SYSCALL_DEFINE5(setxattr, const char __user *, pathname, |
662 | const char __user *, name, const void __user *, value, | |
663 | size_t, size, int, flags) | |
664 | { | |
665 | return path_setxattr(pathname, name, value, size, flags, LOOKUP_FOLLOW); | |
666 | } | |
667 | ||
64fd1de3 HC |
668 | SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname, |
669 | const char __user *, name, const void __user *, value, | |
670 | size_t, size, int, flags) | |
1da177e4 | 671 | { |
8cc43116 | 672 | return path_setxattr(pathname, name, value, size, flags, 0); |
1da177e4 LT |
673 | } |
674 | ||
64fd1de3 HC |
675 | SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name, |
676 | const void __user *,value, size_t, size, int, flags) | |
1da177e4 | 677 | { |
2903ff01 | 678 | struct fd f = fdget(fd); |
1da177e4 LT |
679 | int error = -EBADF; |
680 | ||
2903ff01 | 681 | if (!f.file) |
1da177e4 | 682 | return error; |
9f45f5bf | 683 | audit_file(f.file); |
6742cee0 | 684 | error = mnt_want_write_file(f.file); |
18f335af | 685 | if (!error) { |
c7c7a1a1 TA |
686 | error = setxattr(file_mnt_user_ns(f.file), |
687 | f.file->f_path.dentry, name, | |
688 | value, size, flags); | |
6742cee0 | 689 | mnt_drop_write_file(f.file); |
18f335af | 690 | } |
2903ff01 | 691 | fdput(f); |
1da177e4 LT |
692 | return error; |
693 | } | |
694 | ||
695 | /* | |
696 | * Extended attribute GET operations | |
697 | */ | |
c975cad9 SR |
698 | ssize_t |
699 | do_getxattr(struct user_namespace *mnt_userns, struct dentry *d, | |
700 | struct xattr_ctx *ctx) | |
1da177e4 LT |
701 | { |
702 | ssize_t error; | |
c975cad9 | 703 | char *kname = ctx->kname->name; |
1da177e4 | 704 | |
c975cad9 SR |
705 | if (ctx->size) { |
706 | if (ctx->size > XATTR_SIZE_MAX) | |
707 | ctx->size = XATTR_SIZE_MAX; | |
708 | ctx->kvalue = kvzalloc(ctx->size, GFP_KERNEL); | |
709 | if (!ctx->kvalue) | |
752ade68 | 710 | return -ENOMEM; |
1da177e4 LT |
711 | } |
712 | ||
318e6685 CB |
713 | if (is_posix_acl_xattr(ctx->kname->name)) |
714 | error = do_get_acl(mnt_userns, d, kname, ctx->kvalue, ctx->size); | |
715 | else | |
716 | error = vfs_getxattr(mnt_userns, d, kname, ctx->kvalue, ctx->size); | |
f549d6c1 | 717 | if (error > 0) { |
c975cad9 | 718 | if (ctx->size && copy_to_user(ctx->value, ctx->kvalue, error)) |
f549d6c1 | 719 | error = -EFAULT; |
c975cad9 | 720 | } else if (error == -ERANGE && ctx->size >= XATTR_SIZE_MAX) { |
f549d6c1 SS |
721 | /* The file system tried to returned a value bigger |
722 | than XATTR_SIZE_MAX bytes. Not possible. */ | |
723 | error = -E2BIG; | |
1da177e4 | 724 | } |
0b2a6f23 | 725 | |
c975cad9 SR |
726 | return error; |
727 | } | |
728 | ||
729 | static ssize_t | |
730 | getxattr(struct user_namespace *mnt_userns, struct dentry *d, | |
731 | const char __user *name, void __user *value, size_t size) | |
732 | { | |
733 | ssize_t error; | |
734 | struct xattr_name kname; | |
735 | struct xattr_ctx ctx = { | |
736 | .value = value, | |
737 | .kvalue = NULL, | |
738 | .size = size, | |
739 | .kname = &kname, | |
740 | .flags = 0, | |
741 | }; | |
742 | ||
743 | error = strncpy_from_user(kname.name, name, sizeof(kname.name)); | |
744 | if (error == 0 || error == sizeof(kname.name)) | |
745 | error = -ERANGE; | |
746 | if (error < 0) | |
747 | return error; | |
748 | ||
749 | error = do_getxattr(mnt_userns, d, &ctx); | |
0b2a6f23 | 750 | |
c975cad9 | 751 | kvfree(ctx.kvalue); |
1da177e4 LT |
752 | return error; |
753 | } | |
754 | ||
8cc43116 EB |
755 | static ssize_t path_getxattr(const char __user *pathname, |
756 | const char __user *name, void __user *value, | |
757 | size_t size, unsigned int lookup_flags) | |
1da177e4 | 758 | { |
2d8f3038 | 759 | struct path path; |
1da177e4 | 760 | ssize_t error; |
60e66b48 JL |
761 | retry: |
762 | error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); | |
1da177e4 LT |
763 | if (error) |
764 | return error; | |
c7c7a1a1 | 765 | error = getxattr(mnt_user_ns(path.mnt), path.dentry, name, value, size); |
2d8f3038 | 766 | path_put(&path); |
60e66b48 JL |
767 | if (retry_estale(error, lookup_flags)) { |
768 | lookup_flags |= LOOKUP_REVAL; | |
769 | goto retry; | |
770 | } | |
1da177e4 LT |
771 | return error; |
772 | } | |
773 | ||
8cc43116 EB |
774 | SYSCALL_DEFINE4(getxattr, const char __user *, pathname, |
775 | const char __user *, name, void __user *, value, size_t, size) | |
776 | { | |
777 | return path_getxattr(pathname, name, value, size, LOOKUP_FOLLOW); | |
778 | } | |
779 | ||
64fd1de3 HC |
780 | SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname, |
781 | const char __user *, name, void __user *, value, size_t, size) | |
1da177e4 | 782 | { |
8cc43116 | 783 | return path_getxattr(pathname, name, value, size, 0); |
1da177e4 LT |
784 | } |
785 | ||
64fd1de3 HC |
786 | SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name, |
787 | void __user *, value, size_t, size) | |
1da177e4 | 788 | { |
2903ff01 | 789 | struct fd f = fdget(fd); |
1da177e4 LT |
790 | ssize_t error = -EBADF; |
791 | ||
2903ff01 | 792 | if (!f.file) |
1da177e4 | 793 | return error; |
9f45f5bf | 794 | audit_file(f.file); |
c7c7a1a1 TA |
795 | error = getxattr(file_mnt_user_ns(f.file), f.file->f_path.dentry, |
796 | name, value, size); | |
2903ff01 | 797 | fdput(f); |
1da177e4 LT |
798 | return error; |
799 | } | |
800 | ||
801 | /* | |
802 | * Extended attribute LIST operations | |
803 | */ | |
804 | static ssize_t | |
805 | listxattr(struct dentry *d, char __user *list, size_t size) | |
806 | { | |
807 | ssize_t error; | |
808 | char *klist = NULL; | |
809 | ||
810 | if (size) { | |
811 | if (size > XATTR_LIST_MAX) | |
812 | size = XATTR_LIST_MAX; | |
752ade68 MH |
813 | klist = kvmalloc(size, GFP_KERNEL); |
814 | if (!klist) | |
815 | return -ENOMEM; | |
1da177e4 LT |
816 | } |
817 | ||
659564c8 | 818 | error = vfs_listxattr(d, klist, size); |
f549d6c1 SS |
819 | if (error > 0) { |
820 | if (size && copy_to_user(list, klist, error)) | |
821 | error = -EFAULT; | |
822 | } else if (error == -ERANGE && size >= XATTR_LIST_MAX) { | |
823 | /* The file system tried to returned a list bigger | |
824 | than XATTR_LIST_MAX bytes. Not possible. */ | |
825 | error = -E2BIG; | |
1da177e4 | 826 | } |
0b2a6f23 RW |
827 | |
828 | kvfree(klist); | |
829 | ||
1da177e4 LT |
830 | return error; |
831 | } | |
832 | ||
8cc43116 EB |
833 | static ssize_t path_listxattr(const char __user *pathname, char __user *list, |
834 | size_t size, unsigned int lookup_flags) | |
1da177e4 | 835 | { |
2d8f3038 | 836 | struct path path; |
1da177e4 | 837 | ssize_t error; |
10a90cf3 JL |
838 | retry: |
839 | error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); | |
1da177e4 LT |
840 | if (error) |
841 | return error; | |
2d8f3038 AV |
842 | error = listxattr(path.dentry, list, size); |
843 | path_put(&path); | |
10a90cf3 JL |
844 | if (retry_estale(error, lookup_flags)) { |
845 | lookup_flags |= LOOKUP_REVAL; | |
846 | goto retry; | |
847 | } | |
1da177e4 LT |
848 | return error; |
849 | } | |
850 | ||
8cc43116 EB |
851 | SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list, |
852 | size_t, size) | |
853 | { | |
854 | return path_listxattr(pathname, list, size, LOOKUP_FOLLOW); | |
855 | } | |
856 | ||
64fd1de3 HC |
857 | SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list, |
858 | size_t, size) | |
1da177e4 | 859 | { |
8cc43116 | 860 | return path_listxattr(pathname, list, size, 0); |
1da177e4 LT |
861 | } |
862 | ||
64fd1de3 | 863 | SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size) |
1da177e4 | 864 | { |
2903ff01 | 865 | struct fd f = fdget(fd); |
1da177e4 LT |
866 | ssize_t error = -EBADF; |
867 | ||
2903ff01 | 868 | if (!f.file) |
1da177e4 | 869 | return error; |
9f45f5bf | 870 | audit_file(f.file); |
2903ff01 AV |
871 | error = listxattr(f.file->f_path.dentry, list, size); |
872 | fdput(f); | |
1da177e4 LT |
873 | return error; |
874 | } | |
875 | ||
876 | /* | |
877 | * Extended attribute REMOVE operations | |
878 | */ | |
879 | static long | |
c7c7a1a1 TA |
880 | removexattr(struct user_namespace *mnt_userns, struct dentry *d, |
881 | const char __user *name) | |
1da177e4 LT |
882 | { |
883 | int error; | |
884 | char kname[XATTR_NAME_MAX + 1]; | |
885 | ||
886 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
887 | if (error == 0 || error == sizeof(kname)) | |
888 | error = -ERANGE; | |
889 | if (error < 0) | |
890 | return error; | |
891 | ||
318e6685 CB |
892 | if (is_posix_acl_xattr(kname)) |
893 | return vfs_remove_acl(mnt_userns, d, kname); | |
894 | ||
c7c7a1a1 | 895 | return vfs_removexattr(mnt_userns, d, kname); |
1da177e4 LT |
896 | } |
897 | ||
8cc43116 EB |
898 | static int path_removexattr(const char __user *pathname, |
899 | const char __user *name, unsigned int lookup_flags) | |
1da177e4 | 900 | { |
2d8f3038 | 901 | struct path path; |
1da177e4 | 902 | int error; |
12f06212 JL |
903 | retry: |
904 | error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); | |
1da177e4 LT |
905 | if (error) |
906 | return error; | |
2d8f3038 | 907 | error = mnt_want_write(path.mnt); |
18f335af | 908 | if (!error) { |
c7c7a1a1 | 909 | error = removexattr(mnt_user_ns(path.mnt), path.dentry, name); |
2d8f3038 | 910 | mnt_drop_write(path.mnt); |
18f335af | 911 | } |
2d8f3038 | 912 | path_put(&path); |
12f06212 JL |
913 | if (retry_estale(error, lookup_flags)) { |
914 | lookup_flags |= LOOKUP_REVAL; | |
915 | goto retry; | |
916 | } | |
1da177e4 LT |
917 | return error; |
918 | } | |
919 | ||
8cc43116 EB |
920 | SYSCALL_DEFINE2(removexattr, const char __user *, pathname, |
921 | const char __user *, name) | |
922 | { | |
923 | return path_removexattr(pathname, name, LOOKUP_FOLLOW); | |
924 | } | |
925 | ||
6a6160a7 HC |
926 | SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname, |
927 | const char __user *, name) | |
1da177e4 | 928 | { |
8cc43116 | 929 | return path_removexattr(pathname, name, 0); |
1da177e4 LT |
930 | } |
931 | ||
6a6160a7 | 932 | SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name) |
1da177e4 | 933 | { |
2903ff01 | 934 | struct fd f = fdget(fd); |
1da177e4 LT |
935 | int error = -EBADF; |
936 | ||
2903ff01 | 937 | if (!f.file) |
1da177e4 | 938 | return error; |
9f45f5bf | 939 | audit_file(f.file); |
6742cee0 | 940 | error = mnt_want_write_file(f.file); |
18f335af | 941 | if (!error) { |
c7c7a1a1 TA |
942 | error = removexattr(file_mnt_user_ns(f.file), |
943 | f.file->f_path.dentry, name); | |
6742cee0 | 944 | mnt_drop_write_file(f.file); |
18f335af | 945 | } |
2903ff01 | 946 | fdput(f); |
1da177e4 LT |
947 | return error; |
948 | } | |
949 | ||
1da177e4 LT |
950 | /* |
951 | * Combine the results of the list() operation from every xattr_handler in the | |
952 | * list. | |
953 | */ | |
954 | ssize_t | |
955 | generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) | |
956 | { | |
bb435453 | 957 | const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr; |
1da177e4 LT |
958 | unsigned int size = 0; |
959 | ||
960 | if (!buffer) { | |
431547b3 | 961 | for_each_xattr_handler(handlers, handler) { |
764a5c6b AG |
962 | if (!handler->name || |
963 | (handler->list && !handler->list(dentry))) | |
c4803c49 | 964 | continue; |
764a5c6b | 965 | size += strlen(handler->name) + 1; |
431547b3 | 966 | } |
1da177e4 LT |
967 | } else { |
968 | char *buf = buffer; | |
764a5c6b | 969 | size_t len; |
1da177e4 LT |
970 | |
971 | for_each_xattr_handler(handlers, handler) { | |
764a5c6b AG |
972 | if (!handler->name || |
973 | (handler->list && !handler->list(dentry))) | |
c4803c49 | 974 | continue; |
764a5c6b AG |
975 | len = strlen(handler->name); |
976 | if (len + 1 > buffer_size) | |
1da177e4 | 977 | return -ERANGE; |
764a5c6b AG |
978 | memcpy(buf, handler->name, len + 1); |
979 | buf += len + 1; | |
980 | buffer_size -= len + 1; | |
1da177e4 LT |
981 | } |
982 | size = buf - buffer; | |
983 | } | |
984 | return size; | |
985 | } | |
1da177e4 | 986 | EXPORT_SYMBOL(generic_listxattr); |
38f38657 | 987 | |
e409de99 AG |
988 | /** |
989 | * xattr_full_name - Compute full attribute name from suffix | |
990 | * | |
991 | * @handler: handler of the xattr_handler operation | |
992 | * @name: name passed to the xattr_handler operation | |
993 | * | |
994 | * The get and set xattr handler operations are called with the remainder of | |
995 | * the attribute name after skipping the handler's prefix: for example, "foo" | |
996 | * is passed to the get operation of a handler with prefix "user." to get | |
997 | * attribute "user.foo". The full name is still "there" in the name though. | |
998 | * | |
999 | * Note: the list xattr handler operation when called from the vfs is passed a | |
1000 | * NULL name; some file systems use this operation internally, with varying | |
1001 | * semantics. | |
1002 | */ | |
1003 | const char *xattr_full_name(const struct xattr_handler *handler, | |
1004 | const char *name) | |
1005 | { | |
98e9cb57 | 1006 | size_t prefix_len = strlen(xattr_prefix(handler)); |
e409de99 AG |
1007 | |
1008 | return name - prefix_len; | |
1009 | } | |
1010 | EXPORT_SYMBOL(xattr_full_name); | |
1011 | ||
38f38657 AR |
1012 | /* |
1013 | * Allocate new xattr and copy in the value; but leave the name to callers. | |
1014 | */ | |
1015 | struct simple_xattr *simple_xattr_alloc(const void *value, size_t size) | |
1016 | { | |
1017 | struct simple_xattr *new_xattr; | |
1018 | size_t len; | |
1019 | ||
1020 | /* wrap around? */ | |
1021 | len = sizeof(*new_xattr) + size; | |
4e66d445 | 1022 | if (len < sizeof(*new_xattr)) |
38f38657 AR |
1023 | return NULL; |
1024 | ||
fdc85222 | 1025 | new_xattr = kvmalloc(len, GFP_KERNEL); |
38f38657 AR |
1026 | if (!new_xattr) |
1027 | return NULL; | |
1028 | ||
1029 | new_xattr->size = size; | |
1030 | memcpy(new_xattr->value, value, size); | |
1031 | return new_xattr; | |
1032 | } | |
1033 | ||
1034 | /* | |
1035 | * xattr GET operation for in-memory/pseudo filesystems | |
1036 | */ | |
1037 | int simple_xattr_get(struct simple_xattrs *xattrs, const char *name, | |
1038 | void *buffer, size_t size) | |
1039 | { | |
1040 | struct simple_xattr *xattr; | |
1041 | int ret = -ENODATA; | |
1042 | ||
1043 | spin_lock(&xattrs->lock); | |
1044 | list_for_each_entry(xattr, &xattrs->head, list) { | |
1045 | if (strcmp(name, xattr->name)) | |
1046 | continue; | |
1047 | ||
1048 | ret = xattr->size; | |
1049 | if (buffer) { | |
1050 | if (size < xattr->size) | |
1051 | ret = -ERANGE; | |
1052 | else | |
1053 | memcpy(buffer, xattr->value, xattr->size); | |
1054 | } | |
1055 | break; | |
1056 | } | |
1057 | spin_unlock(&xattrs->lock); | |
1058 | return ret; | |
1059 | } | |
1060 | ||
aa7c5241 AG |
1061 | /** |
1062 | * simple_xattr_set - xattr SET operation for in-memory/pseudo filesystems | |
1063 | * @xattrs: target simple_xattr list | |
1064 | * @name: name of the extended attribute | |
1065 | * @value: value of the xattr. If %NULL, will remove the attribute. | |
1066 | * @size: size of the new xattr | |
1067 | * @flags: %XATTR_{CREATE|REPLACE} | |
a46a2295 | 1068 | * @removed_size: returns size of the removed xattr, -1 if none removed |
aa7c5241 AG |
1069 | * |
1070 | * %XATTR_CREATE is set, the xattr shouldn't exist already; otherwise fails | |
1071 | * with -EEXIST. If %XATTR_REPLACE is set, the xattr should exist; | |
1072 | * otherwise, fails with -ENODATA. | |
1073 | * | |
1074 | * Returns 0 on success, -errno on failure. | |
1075 | */ | |
1076 | int simple_xattr_set(struct simple_xattrs *xattrs, const char *name, | |
a46a2295 DX |
1077 | const void *value, size_t size, int flags, |
1078 | ssize_t *removed_size) | |
38f38657 AR |
1079 | { |
1080 | struct simple_xattr *xattr; | |
43385846 | 1081 | struct simple_xattr *new_xattr = NULL; |
38f38657 AR |
1082 | int err = 0; |
1083 | ||
772b3140 DX |
1084 | if (removed_size) |
1085 | *removed_size = -1; | |
1086 | ||
38f38657 AR |
1087 | /* value == NULL means remove */ |
1088 | if (value) { | |
1089 | new_xattr = simple_xattr_alloc(value, size); | |
1090 | if (!new_xattr) | |
1091 | return -ENOMEM; | |
1092 | ||
1093 | new_xattr->name = kstrdup(name, GFP_KERNEL); | |
1094 | if (!new_xattr->name) { | |
fdc85222 | 1095 | kvfree(new_xattr); |
38f38657 AR |
1096 | return -ENOMEM; |
1097 | } | |
1098 | } | |
1099 | ||
1100 | spin_lock(&xattrs->lock); | |
1101 | list_for_each_entry(xattr, &xattrs->head, list) { | |
1102 | if (!strcmp(name, xattr->name)) { | |
1103 | if (flags & XATTR_CREATE) { | |
1104 | xattr = new_xattr; | |
1105 | err = -EEXIST; | |
1106 | } else if (new_xattr) { | |
1107 | list_replace(&xattr->list, &new_xattr->list); | |
a46a2295 DX |
1108 | if (removed_size) |
1109 | *removed_size = xattr->size; | |
38f38657 AR |
1110 | } else { |
1111 | list_del(&xattr->list); | |
a46a2295 DX |
1112 | if (removed_size) |
1113 | *removed_size = xattr->size; | |
38f38657 AR |
1114 | } |
1115 | goto out; | |
1116 | } | |
1117 | } | |
1118 | if (flags & XATTR_REPLACE) { | |
1119 | xattr = new_xattr; | |
1120 | err = -ENODATA; | |
1121 | } else { | |
1122 | list_add(&new_xattr->list, &xattrs->head); | |
1123 | xattr = NULL; | |
1124 | } | |
1125 | out: | |
1126 | spin_unlock(&xattrs->lock); | |
1127 | if (xattr) { | |
1128 | kfree(xattr->name); | |
fdc85222 | 1129 | kvfree(xattr); |
38f38657 AR |
1130 | } |
1131 | return err; | |
1132 | ||
1133 | } | |
1134 | ||
38f38657 AR |
1135 | static bool xattr_is_trusted(const char *name) |
1136 | { | |
1137 | return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN); | |
1138 | } | |
1139 | ||
786534b9 AG |
1140 | static int xattr_list_one(char **buffer, ssize_t *remaining_size, |
1141 | const char *name) | |
1142 | { | |
1143 | size_t len = strlen(name) + 1; | |
1144 | if (*buffer) { | |
1145 | if (*remaining_size < len) | |
1146 | return -ERANGE; | |
1147 | memcpy(*buffer, name, len); | |
1148 | *buffer += len; | |
1149 | } | |
1150 | *remaining_size -= len; | |
1151 | return 0; | |
1152 | } | |
1153 | ||
38f38657 AR |
1154 | /* |
1155 | * xattr LIST operation for in-memory/pseudo filesystems | |
1156 | */ | |
786534b9 AG |
1157 | ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs, |
1158 | char *buffer, size_t size) | |
38f38657 AR |
1159 | { |
1160 | bool trusted = capable(CAP_SYS_ADMIN); | |
1161 | struct simple_xattr *xattr; | |
786534b9 | 1162 | ssize_t remaining_size = size; |
0e9a7da5 | 1163 | int err = 0; |
786534b9 AG |
1164 | |
1165 | #ifdef CONFIG_FS_POSIX_ACL | |
ffc4c922 AG |
1166 | if (IS_POSIXACL(inode)) { |
1167 | if (inode->i_acl) { | |
1168 | err = xattr_list_one(&buffer, &remaining_size, | |
1169 | XATTR_NAME_POSIX_ACL_ACCESS); | |
1170 | if (err) | |
1171 | return err; | |
1172 | } | |
1173 | if (inode->i_default_acl) { | |
1174 | err = xattr_list_one(&buffer, &remaining_size, | |
1175 | XATTR_NAME_POSIX_ACL_DEFAULT); | |
1176 | if (err) | |
1177 | return err; | |
1178 | } | |
786534b9 AG |
1179 | } |
1180 | #endif | |
38f38657 AR |
1181 | |
1182 | spin_lock(&xattrs->lock); | |
1183 | list_for_each_entry(xattr, &xattrs->head, list) { | |
38f38657 AR |
1184 | /* skip "trusted." attributes for unprivileged callers */ |
1185 | if (!trusted && xattr_is_trusted(xattr->name)) | |
1186 | continue; | |
1187 | ||
786534b9 AG |
1188 | err = xattr_list_one(&buffer, &remaining_size, xattr->name); |
1189 | if (err) | |
0e9a7da5 | 1190 | break; |
38f38657 AR |
1191 | } |
1192 | spin_unlock(&xattrs->lock); | |
1193 | ||
0e9a7da5 | 1194 | return err ? err : size - remaining_size; |
38f38657 AR |
1195 | } |
1196 | ||
4895768b AR |
1197 | /* |
1198 | * Adds an extended attribute to the list | |
1199 | */ | |
38f38657 AR |
1200 | void simple_xattr_list_add(struct simple_xattrs *xattrs, |
1201 | struct simple_xattr *new_xattr) | |
1202 | { | |
1203 | spin_lock(&xattrs->lock); | |
1204 | list_add(&new_xattr->list, &xattrs->head); | |
1205 | spin_unlock(&xattrs->lock); | |
1206 | } |