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Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | File: fs/xattr.c | |
3 | ||
4 | Extended attribute handling. | |
5 | ||
6 | Copyright (C) 2001 by Andreas Gruenbacher <a.gruenbacher@computer.org> | |
7 | Copyright (C) 2001 SGI - Silicon Graphics, Inc <linux-xfs@oss.sgi.com> | |
8 | Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com> | |
9 | */ | |
10 | #include <linux/fs.h> | |
11 | #include <linux/slab.h> | |
1da177e4 LT |
12 | #include <linux/file.h> |
13 | #include <linux/xattr.h> | |
18f335af | 14 | #include <linux/mount.h> |
1da177e4 LT |
15 | #include <linux/namei.h> |
16 | #include <linux/security.h> | |
c7b87de2 | 17 | #include <linux/evm.h> |
1da177e4 | 18 | #include <linux/syscalls.h> |
630d9c47 | 19 | #include <linux/export.h> |
0eeca283 | 20 | #include <linux/fsnotify.h> |
73241ccc | 21 | #include <linux/audit.h> |
0d08d7b7 | 22 | #include <linux/vmalloc.h> |
2f6f0654 | 23 | #include <linux/posix_acl_xattr.h> |
1da177e4 | 24 | |
7c0f6ba6 | 25 | #include <linux/uaccess.h> |
5be196e5 | 26 | |
b6ba1177 AG |
27 | static const char * |
28 | strcmp_prefix(const char *a, const char *a_prefix) | |
29 | { | |
30 | while (*a_prefix && *a == *a_prefix) { | |
31 | a++; | |
32 | a_prefix++; | |
33 | } | |
34 | return *a_prefix ? NULL : a; | |
35 | } | |
36 | ||
37 | /* | |
38 | * In order to implement different sets of xattr operations for each xattr | |
6c6ef9f2 AG |
39 | * prefix, a filesystem should create a null-terminated array of struct |
40 | * xattr_handler (one for each prefix) and hang a pointer to it off of the | |
41 | * s_xattr field of the superblock. | |
b6ba1177 AG |
42 | */ |
43 | #define for_each_xattr_handler(handlers, handler) \ | |
44 | if (handlers) \ | |
45 | for ((handler) = *(handlers)++; \ | |
46 | (handler) != NULL; \ | |
47 | (handler) = *(handlers)++) | |
48 | ||
49 | /* | |
50 | * Find the xattr_handler with the matching prefix. | |
51 | */ | |
52 | static const struct xattr_handler * | |
d0a5b995 | 53 | xattr_resolve_name(struct inode *inode, const char **name) |
b6ba1177 | 54 | { |
d0a5b995 | 55 | const struct xattr_handler **handlers = inode->i_sb->s_xattr; |
b6ba1177 AG |
56 | const struct xattr_handler *handler; |
57 | ||
5f6e59ae AG |
58 | if (!(inode->i_opflags & IOP_XATTR)) { |
59 | if (unlikely(is_bad_inode(inode))) | |
60 | return ERR_PTR(-EIO); | |
d0a5b995 | 61 | return ERR_PTR(-EOPNOTSUPP); |
5f6e59ae | 62 | } |
b6ba1177 AG |
63 | for_each_xattr_handler(handlers, handler) { |
64 | const char *n; | |
65 | ||
66 | n = strcmp_prefix(*name, xattr_prefix(handler)); | |
67 | if (n) { | |
68 | if (!handler->prefix ^ !*n) { | |
69 | if (*n) | |
70 | continue; | |
71 | return ERR_PTR(-EINVAL); | |
72 | } | |
73 | *name = n; | |
74 | return handler; | |
75 | } | |
76 | } | |
77 | return ERR_PTR(-EOPNOTSUPP); | |
78 | } | |
79 | ||
e0ad7b07 | 80 | /* |
81 | * Check permissions for extended attribute access. This is a bit complicated | |
82 | * because different namespaces have very different rules. | |
83 | */ | |
84 | static int | |
85 | xattr_permission(struct inode *inode, const char *name, int mask) | |
86 | { | |
87 | /* | |
88 | * We can never set or remove an extended attribute on a read-only | |
89 | * filesystem or on an immutable / append-only inode. | |
90 | */ | |
91 | if (mask & MAY_WRITE) { | |
e0ad7b07 | 92 | if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) |
93 | return -EPERM; | |
0bd23d09 EB |
94 | /* |
95 | * Updating an xattr will likely cause i_uid and i_gid | |
96 | * to be writen back improperly if their true value is | |
97 | * unknown to the vfs. | |
98 | */ | |
99 | if (HAS_UNMAPPED_ID(inode)) | |
100 | return -EPERM; | |
e0ad7b07 | 101 | } |
102 | ||
103 | /* | |
104 | * No restriction for security.* and system.* from the VFS. Decision | |
105 | * on these is left to the underlying filesystem / security module. | |
106 | */ | |
107 | if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) || | |
108 | !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
109 | return 0; | |
110 | ||
111 | /* | |
55b23bde | 112 | * The trusted.* namespace can only be accessed by privileged users. |
e0ad7b07 | 113 | */ |
55b23bde AG |
114 | if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) { |
115 | if (!capable(CAP_SYS_ADMIN)) | |
116 | return (mask & MAY_WRITE) ? -EPERM : -ENODATA; | |
117 | return 0; | |
118 | } | |
e0ad7b07 | 119 | |
55b23bde AG |
120 | /* |
121 | * In the user.* namespace, only regular files and directories can have | |
f1f2d871 | 122 | * extended attributes. For sticky directories, only the owner and |
55b23bde | 123 | * privileged users can write attributes. |
f1f2d871 | 124 | */ |
e0ad7b07 | 125 | if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) { |
f1f2d871 | 126 | if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode)) |
55b23bde | 127 | return (mask & MAY_WRITE) ? -EPERM : -ENODATA; |
f1f2d871 | 128 | if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) && |
2e149670 | 129 | (mask & MAY_WRITE) && !inode_owner_or_capable(inode)) |
e0ad7b07 | 130 | return -EPERM; |
131 | } | |
132 | ||
f419a2e3 | 133 | return inode_permission(inode, mask); |
e0ad7b07 | 134 | } |
135 | ||
5d6c3191 AG |
136 | int |
137 | __vfs_setxattr(struct dentry *dentry, struct inode *inode, const char *name, | |
138 | const void *value, size_t size, int flags) | |
139 | { | |
6c6ef9f2 AG |
140 | const struct xattr_handler *handler; |
141 | ||
142 | handler = xattr_resolve_name(inode, &name); | |
143 | if (IS_ERR(handler)) | |
144 | return PTR_ERR(handler); | |
145 | if (!handler->set) | |
5d6c3191 | 146 | return -EOPNOTSUPP; |
6c6ef9f2 AG |
147 | if (size == 0) |
148 | value = ""; /* empty EA, do not remove */ | |
149 | return handler->set(handler, dentry, inode, name, value, size, flags); | |
5d6c3191 AG |
150 | } |
151 | EXPORT_SYMBOL(__vfs_setxattr); | |
152 | ||
b1ab7e4b DQ |
153 | /** |
154 | * __vfs_setxattr_noperm - perform setxattr operation without performing | |
155 | * permission checks. | |
156 | * | |
157 | * @dentry - object to perform setxattr on | |
158 | * @name - xattr name to set | |
159 | * @value - value to set @name to | |
160 | * @size - size of @value | |
161 | * @flags - flags to pass into filesystem operations | |
162 | * | |
163 | * returns the result of the internal setxattr or setsecurity operations. | |
164 | * | |
165 | * This function requires the caller to lock the inode's i_mutex before it | |
166 | * is executed. It also assumes that the caller will make the appropriate | |
167 | * permission checks. | |
168 | */ | |
169 | int __vfs_setxattr_noperm(struct dentry *dentry, const char *name, | |
170 | const void *value, size_t size, int flags) | |
5be196e5 CH |
171 | { |
172 | struct inode *inode = dentry->d_inode; | |
4a590153 | 173 | int error = -EAGAIN; |
69b45732 AK |
174 | int issec = !strncmp(name, XATTR_SECURITY_PREFIX, |
175 | XATTR_SECURITY_PREFIX_LEN); | |
e0ad7b07 | 176 | |
69b45732 AK |
177 | if (issec) |
178 | inode->i_flags &= ~S_NOSEC; | |
6c6ef9f2 | 179 | if (inode->i_opflags & IOP_XATTR) { |
5d6c3191 | 180 | error = __vfs_setxattr(dentry, inode, name, value, size, flags); |
5be196e5 CH |
181 | if (!error) { |
182 | fsnotify_xattr(dentry); | |
183 | security_inode_post_setxattr(dentry, name, value, | |
184 | size, flags); | |
185 | } | |
4a590153 | 186 | } else { |
5f6e59ae AG |
187 | if (unlikely(is_bad_inode(inode))) |
188 | return -EIO; | |
4a590153 AG |
189 | } |
190 | if (error == -EAGAIN) { | |
191 | error = -EOPNOTSUPP; | |
192 | ||
193 | if (issec) { | |
194 | const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; | |
195 | ||
196 | error = security_inode_setsecurity(inode, suffix, value, | |
197 | size, flags); | |
198 | if (!error) | |
199 | fsnotify_xattr(dentry); | |
200 | } | |
5be196e5 | 201 | } |
b1ab7e4b DQ |
202 | |
203 | return error; | |
204 | } | |
25b33138 | 205 | EXPORT_SYMBOL_GPL(__vfs_setxattr_noperm); |
b1ab7e4b DQ |
206 | |
207 | ||
208 | int | |
209 | vfs_setxattr(struct dentry *dentry, const char *name, const void *value, | |
210 | size_t size, int flags) | |
211 | { | |
212 | struct inode *inode = dentry->d_inode; | |
213 | int error; | |
214 | ||
215 | error = xattr_permission(inode, name, MAY_WRITE); | |
216 | if (error) | |
217 | return error; | |
218 | ||
5955102c | 219 | inode_lock(inode); |
b1ab7e4b DQ |
220 | error = security_inode_setxattr(dentry, name, value, size, flags); |
221 | if (error) | |
222 | goto out; | |
223 | ||
224 | error = __vfs_setxattr_noperm(dentry, name, value, size, flags); | |
225 | ||
5be196e5 | 226 | out: |
5955102c | 227 | inode_unlock(inode); |
5be196e5 CH |
228 | return error; |
229 | } | |
230 | EXPORT_SYMBOL_GPL(vfs_setxattr); | |
231 | ||
42492594 DQ |
232 | ssize_t |
233 | xattr_getsecurity(struct inode *inode, const char *name, void *value, | |
234 | size_t size) | |
235 | { | |
236 | void *buffer = NULL; | |
237 | ssize_t len; | |
238 | ||
239 | if (!value || !size) { | |
240 | len = security_inode_getsecurity(inode, name, &buffer, false); | |
241 | goto out_noalloc; | |
242 | } | |
243 | ||
244 | len = security_inode_getsecurity(inode, name, &buffer, true); | |
245 | if (len < 0) | |
246 | return len; | |
247 | if (size < len) { | |
248 | len = -ERANGE; | |
249 | goto out; | |
250 | } | |
251 | memcpy(value, buffer, len); | |
252 | out: | |
253 | security_release_secctx(buffer, len); | |
254 | out_noalloc: | |
255 | return len; | |
256 | } | |
257 | EXPORT_SYMBOL_GPL(xattr_getsecurity); | |
258 | ||
1601fbad MZ |
259 | /* |
260 | * vfs_getxattr_alloc - allocate memory, if necessary, before calling getxattr | |
261 | * | |
262 | * Allocate memory, if not already allocated, or re-allocate correct size, | |
263 | * before retrieving the extended attribute. | |
264 | * | |
265 | * Returns the result of alloc, if failed, or the getxattr operation. | |
266 | */ | |
267 | ssize_t | |
268 | vfs_getxattr_alloc(struct dentry *dentry, const char *name, char **xattr_value, | |
269 | size_t xattr_size, gfp_t flags) | |
270 | { | |
6c6ef9f2 | 271 | const struct xattr_handler *handler; |
1601fbad MZ |
272 | struct inode *inode = dentry->d_inode; |
273 | char *value = *xattr_value; | |
274 | int error; | |
275 | ||
276 | error = xattr_permission(inode, name, MAY_READ); | |
277 | if (error) | |
278 | return error; | |
279 | ||
6c6ef9f2 AG |
280 | handler = xattr_resolve_name(inode, &name); |
281 | if (IS_ERR(handler)) | |
282 | return PTR_ERR(handler); | |
283 | if (!handler->get) | |
1601fbad | 284 | return -EOPNOTSUPP; |
6c6ef9f2 | 285 | error = handler->get(handler, dentry, inode, name, NULL, 0); |
1601fbad MZ |
286 | if (error < 0) |
287 | return error; | |
288 | ||
289 | if (!value || (error > xattr_size)) { | |
290 | value = krealloc(*xattr_value, error + 1, flags); | |
291 | if (!value) | |
292 | return -ENOMEM; | |
293 | memset(value, 0, error + 1); | |
294 | } | |
295 | ||
6c6ef9f2 | 296 | error = handler->get(handler, dentry, inode, name, value, error); |
1601fbad MZ |
297 | *xattr_value = value; |
298 | return error; | |
299 | } | |
5b88fdd9 | 300 | EXPORT_SYMBOL_GPL(vfs_getxattr_alloc); |
1601fbad | 301 | |
5d6c3191 AG |
302 | ssize_t |
303 | __vfs_getxattr(struct dentry *dentry, struct inode *inode, const char *name, | |
304 | void *value, size_t size) | |
305 | { | |
6c6ef9f2 AG |
306 | const struct xattr_handler *handler; |
307 | ||
308 | handler = xattr_resolve_name(inode, &name); | |
309 | if (IS_ERR(handler)) | |
310 | return PTR_ERR(handler); | |
311 | if (!handler->get) | |
5d6c3191 | 312 | return -EOPNOTSUPP; |
6c6ef9f2 | 313 | return handler->get(handler, dentry, inode, name, value, size); |
5d6c3191 AG |
314 | } |
315 | EXPORT_SYMBOL(__vfs_getxattr); | |
316 | ||
5be196e5 | 317 | ssize_t |
8f0cfa52 | 318 | vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size) |
5be196e5 CH |
319 | { |
320 | struct inode *inode = dentry->d_inode; | |
321 | int error; | |
322 | ||
e0ad7b07 | 323 | error = xattr_permission(inode, name, MAY_READ); |
324 | if (error) | |
325 | return error; | |
326 | ||
5be196e5 CH |
327 | error = security_inode_getxattr(dentry, name); |
328 | if (error) | |
329 | return error; | |
330 | ||
5be196e5 | 331 | if (!strncmp(name, XATTR_SECURITY_PREFIX, |
e0ad7b07 | 332 | XATTR_SECURITY_PREFIX_LEN)) { |
333 | const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; | |
42492594 | 334 | int ret = xattr_getsecurity(inode, suffix, value, size); |
5be196e5 CH |
335 | /* |
336 | * Only overwrite the return value if a security module | |
337 | * is actually active. | |
338 | */ | |
4bea5805 DQ |
339 | if (ret == -EOPNOTSUPP) |
340 | goto nolsm; | |
341 | return ret; | |
5be196e5 | 342 | } |
4bea5805 | 343 | nolsm: |
5d6c3191 | 344 | return __vfs_getxattr(dentry, inode, name, value, size); |
5be196e5 CH |
345 | } |
346 | EXPORT_SYMBOL_GPL(vfs_getxattr); | |
347 | ||
659564c8 | 348 | ssize_t |
bf3ee713 | 349 | vfs_listxattr(struct dentry *dentry, char *list, size_t size) |
659564c8 | 350 | { |
bf3ee713 | 351 | struct inode *inode = d_inode(dentry); |
659564c8 BN |
352 | ssize_t error; |
353 | ||
bf3ee713 | 354 | error = security_inode_listxattr(dentry); |
659564c8 BN |
355 | if (error) |
356 | return error; | |
bf3ee713 AG |
357 | if (inode->i_op->listxattr && (inode->i_opflags & IOP_XATTR)) { |
358 | error = -EOPNOTSUPP; | |
359 | error = inode->i_op->listxattr(dentry, list, size); | |
659564c8 | 360 | } else { |
bf3ee713 | 361 | error = security_inode_listsecurity(inode, list, size); |
659564c8 BN |
362 | if (size && error > size) |
363 | error = -ERANGE; | |
364 | } | |
365 | return error; | |
366 | } | |
367 | EXPORT_SYMBOL_GPL(vfs_listxattr); | |
368 | ||
5be196e5 | 369 | int |
5d6c3191 | 370 | __vfs_removexattr(struct dentry *dentry, const char *name) |
5be196e5 | 371 | { |
6c6ef9f2 AG |
372 | struct inode *inode = d_inode(dentry); |
373 | const struct xattr_handler *handler; | |
5be196e5 | 374 | |
6c6ef9f2 AG |
375 | handler = xattr_resolve_name(inode, &name); |
376 | if (IS_ERR(handler)) | |
377 | return PTR_ERR(handler); | |
378 | if (!handler->set) | |
5be196e5 | 379 | return -EOPNOTSUPP; |
6c6ef9f2 | 380 | return handler->set(handler, dentry, inode, name, NULL, 0, XATTR_REPLACE); |
5d6c3191 AG |
381 | } |
382 | EXPORT_SYMBOL(__vfs_removexattr); | |
383 | ||
25b33138 SF |
384 | /** |
385 | * __vfs_removexattr_noperm - perform removexattr operation without | |
386 | * performing permission checks. | |
387 | * | |
388 | * @dentry - object to perform setxattr on | |
389 | * @name - xattr name to set | |
390 | * | |
391 | * returns the result of the internal setxattr or setsecurity operations. | |
392 | * | |
393 | * This function requires the caller to lock the inode's i_mutex before it | |
394 | * is executed. It also assumes that the caller will make the appropriate | |
395 | * permission checks. | |
396 | */ | |
397 | int | |
398 | __vfs_removexattr_noperm(struct dentry *dentry, const char *name) | |
399 | { | |
400 | int error; | |
401 | ||
402 | error =__vfs_removexattr(dentry, name); | |
403 | if (!error) { | |
404 | fsnotify_xattr(dentry); | |
405 | evm_inode_post_removexattr(dentry, name); | |
406 | } | |
407 | return error; | |
408 | } | |
409 | EXPORT_SYMBOL_GPL(__vfs_removexattr_noperm); | |
410 | ||
5d6c3191 AG |
411 | int |
412 | vfs_removexattr(struct dentry *dentry, const char *name) | |
413 | { | |
414 | struct inode *inode = dentry->d_inode; | |
415 | int error; | |
5be196e5 | 416 | |
e0ad7b07 | 417 | error = xattr_permission(inode, name, MAY_WRITE); |
418 | if (error) | |
419 | return error; | |
420 | ||
5955102c | 421 | inode_lock(inode); |
5be196e5 | 422 | error = security_inode_removexattr(dentry, name); |
7c51bb00 DK |
423 | if (error) |
424 | goto out; | |
5be196e5 | 425 | |
25b33138 | 426 | error = __vfs_removexattr_noperm(dentry, name); |
7c51bb00 DK |
427 | |
428 | out: | |
5955102c | 429 | inode_unlock(inode); |
5be196e5 CH |
430 | return error; |
431 | } | |
432 | EXPORT_SYMBOL_GPL(vfs_removexattr); | |
433 | ||
434 | ||
1da177e4 LT |
435 | /* |
436 | * Extended attribute SET operations | |
437 | */ | |
438 | static long | |
8f0cfa52 | 439 | setxattr(struct dentry *d, const char __user *name, const void __user *value, |
1da177e4 LT |
440 | size_t size, int flags) |
441 | { | |
442 | int error; | |
443 | void *kvalue = NULL; | |
444 | char kname[XATTR_NAME_MAX + 1]; | |
445 | ||
446 | if (flags & ~(XATTR_CREATE|XATTR_REPLACE)) | |
447 | return -EINVAL; | |
448 | ||
449 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
450 | if (error == 0 || error == sizeof(kname)) | |
451 | error = -ERANGE; | |
452 | if (error < 0) | |
453 | return error; | |
454 | ||
455 | if (size) { | |
456 | if (size > XATTR_SIZE_MAX) | |
457 | return -E2BIG; | |
44c82498 AM |
458 | kvalue = kmalloc(size, GFP_KERNEL | __GFP_NOWARN); |
459 | if (!kvalue) { | |
0b2a6f23 RW |
460 | kvalue = vmalloc(size); |
461 | if (!kvalue) | |
44c82498 | 462 | return -ENOMEM; |
44c82498 AM |
463 | } |
464 | if (copy_from_user(kvalue, value, size)) { | |
465 | error = -EFAULT; | |
466 | goto out; | |
467 | } | |
2f6f0654 EB |
468 | if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) || |
469 | (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)) | |
470 | posix_acl_fix_xattr_from_user(kvalue, size); | |
1da177e4 LT |
471 | } |
472 | ||
5be196e5 | 473 | error = vfs_setxattr(d, kname, kvalue, size, flags); |
44c82498 | 474 | out: |
0b2a6f23 RW |
475 | kvfree(kvalue); |
476 | ||
1da177e4 LT |
477 | return error; |
478 | } | |
479 | ||
8cc43116 EB |
480 | static int path_setxattr(const char __user *pathname, |
481 | const char __user *name, const void __user *value, | |
482 | size_t size, int flags, unsigned int lookup_flags) | |
1da177e4 | 483 | { |
2d8f3038 | 484 | struct path path; |
1da177e4 | 485 | int error; |
68f1bb8b JL |
486 | retry: |
487 | error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); | |
1da177e4 LT |
488 | if (error) |
489 | return error; | |
2d8f3038 | 490 | error = mnt_want_write(path.mnt); |
18f335af | 491 | if (!error) { |
2d8f3038 AV |
492 | error = setxattr(path.dentry, name, value, size, flags); |
493 | mnt_drop_write(path.mnt); | |
18f335af | 494 | } |
2d8f3038 | 495 | path_put(&path); |
68f1bb8b JL |
496 | if (retry_estale(error, lookup_flags)) { |
497 | lookup_flags |= LOOKUP_REVAL; | |
498 | goto retry; | |
499 | } | |
1da177e4 LT |
500 | return error; |
501 | } | |
502 | ||
8cc43116 EB |
503 | SYSCALL_DEFINE5(setxattr, const char __user *, pathname, |
504 | const char __user *, name, const void __user *, value, | |
505 | size_t, size, int, flags) | |
506 | { | |
507 | return path_setxattr(pathname, name, value, size, flags, LOOKUP_FOLLOW); | |
508 | } | |
509 | ||
64fd1de3 HC |
510 | SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname, |
511 | const char __user *, name, const void __user *, value, | |
512 | size_t, size, int, flags) | |
1da177e4 | 513 | { |
8cc43116 | 514 | return path_setxattr(pathname, name, value, size, flags, 0); |
1da177e4 LT |
515 | } |
516 | ||
64fd1de3 HC |
517 | SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name, |
518 | const void __user *,value, size_t, size, int, flags) | |
1da177e4 | 519 | { |
2903ff01 | 520 | struct fd f = fdget(fd); |
1da177e4 LT |
521 | int error = -EBADF; |
522 | ||
2903ff01 | 523 | if (!f.file) |
1da177e4 | 524 | return error; |
9f45f5bf | 525 | audit_file(f.file); |
2903ff01 | 526 | error = mnt_want_write_file(f.file); |
18f335af | 527 | if (!error) { |
9f45f5bf | 528 | error = setxattr(f.file->f_path.dentry, name, value, size, flags); |
2903ff01 | 529 | mnt_drop_write_file(f.file); |
18f335af | 530 | } |
2903ff01 | 531 | fdput(f); |
1da177e4 LT |
532 | return error; |
533 | } | |
534 | ||
535 | /* | |
536 | * Extended attribute GET operations | |
537 | */ | |
538 | static ssize_t | |
8f0cfa52 DH |
539 | getxattr(struct dentry *d, const char __user *name, void __user *value, |
540 | size_t size) | |
1da177e4 LT |
541 | { |
542 | ssize_t error; | |
543 | void *kvalue = NULL; | |
544 | char kname[XATTR_NAME_MAX + 1]; | |
545 | ||
546 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
547 | if (error == 0 || error == sizeof(kname)) | |
548 | error = -ERANGE; | |
549 | if (error < 0) | |
550 | return error; | |
551 | ||
552 | if (size) { | |
553 | if (size > XATTR_SIZE_MAX) | |
554 | size = XATTR_SIZE_MAX; | |
779302e6 SL |
555 | kvalue = kzalloc(size, GFP_KERNEL | __GFP_NOWARN); |
556 | if (!kvalue) { | |
0b2a6f23 RW |
557 | kvalue = vmalloc(size); |
558 | if (!kvalue) | |
779302e6 | 559 | return -ENOMEM; |
779302e6 | 560 | } |
1da177e4 LT |
561 | } |
562 | ||
5be196e5 | 563 | error = vfs_getxattr(d, kname, kvalue, size); |
f549d6c1 | 564 | if (error > 0) { |
2f6f0654 EB |
565 | if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) || |
566 | (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)) | |
567 | posix_acl_fix_xattr_to_user(kvalue, size); | |
f549d6c1 SS |
568 | if (size && copy_to_user(value, kvalue, error)) |
569 | error = -EFAULT; | |
570 | } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) { | |
571 | /* The file system tried to returned a value bigger | |
572 | than XATTR_SIZE_MAX bytes. Not possible. */ | |
573 | error = -E2BIG; | |
1da177e4 | 574 | } |
0b2a6f23 RW |
575 | |
576 | kvfree(kvalue); | |
577 | ||
1da177e4 LT |
578 | return error; |
579 | } | |
580 | ||
8cc43116 EB |
581 | static ssize_t path_getxattr(const char __user *pathname, |
582 | const char __user *name, void __user *value, | |
583 | size_t size, unsigned int lookup_flags) | |
1da177e4 | 584 | { |
2d8f3038 | 585 | struct path path; |
1da177e4 | 586 | ssize_t error; |
60e66b48 JL |
587 | retry: |
588 | error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); | |
1da177e4 LT |
589 | if (error) |
590 | return error; | |
2d8f3038 AV |
591 | error = getxattr(path.dentry, name, value, size); |
592 | path_put(&path); | |
60e66b48 JL |
593 | if (retry_estale(error, lookup_flags)) { |
594 | lookup_flags |= LOOKUP_REVAL; | |
595 | goto retry; | |
596 | } | |
1da177e4 LT |
597 | return error; |
598 | } | |
599 | ||
8cc43116 EB |
600 | SYSCALL_DEFINE4(getxattr, const char __user *, pathname, |
601 | const char __user *, name, void __user *, value, size_t, size) | |
602 | { | |
603 | return path_getxattr(pathname, name, value, size, LOOKUP_FOLLOW); | |
604 | } | |
605 | ||
64fd1de3 HC |
606 | SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname, |
607 | const char __user *, name, void __user *, value, size_t, size) | |
1da177e4 | 608 | { |
8cc43116 | 609 | return path_getxattr(pathname, name, value, size, 0); |
1da177e4 LT |
610 | } |
611 | ||
64fd1de3 HC |
612 | SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name, |
613 | void __user *, value, size_t, size) | |
1da177e4 | 614 | { |
2903ff01 | 615 | struct fd f = fdget(fd); |
1da177e4 LT |
616 | ssize_t error = -EBADF; |
617 | ||
2903ff01 | 618 | if (!f.file) |
1da177e4 | 619 | return error; |
9f45f5bf | 620 | audit_file(f.file); |
2903ff01 AV |
621 | error = getxattr(f.file->f_path.dentry, name, value, size); |
622 | fdput(f); | |
1da177e4 LT |
623 | return error; |
624 | } | |
625 | ||
626 | /* | |
627 | * Extended attribute LIST operations | |
628 | */ | |
629 | static ssize_t | |
630 | listxattr(struct dentry *d, char __user *list, size_t size) | |
631 | { | |
632 | ssize_t error; | |
633 | char *klist = NULL; | |
634 | ||
635 | if (size) { | |
636 | if (size > XATTR_LIST_MAX) | |
637 | size = XATTR_LIST_MAX; | |
703bf2d1 | 638 | klist = kmalloc(size, __GFP_NOWARN | GFP_KERNEL); |
0d08d7b7 | 639 | if (!klist) { |
0b2a6f23 RW |
640 | klist = vmalloc(size); |
641 | if (!klist) | |
0d08d7b7 | 642 | return -ENOMEM; |
0d08d7b7 | 643 | } |
1da177e4 LT |
644 | } |
645 | ||
659564c8 | 646 | error = vfs_listxattr(d, klist, size); |
f549d6c1 SS |
647 | if (error > 0) { |
648 | if (size && copy_to_user(list, klist, error)) | |
649 | error = -EFAULT; | |
650 | } else if (error == -ERANGE && size >= XATTR_LIST_MAX) { | |
651 | /* The file system tried to returned a list bigger | |
652 | than XATTR_LIST_MAX bytes. Not possible. */ | |
653 | error = -E2BIG; | |
1da177e4 | 654 | } |
0b2a6f23 RW |
655 | |
656 | kvfree(klist); | |
657 | ||
1da177e4 LT |
658 | return error; |
659 | } | |
660 | ||
8cc43116 EB |
661 | static ssize_t path_listxattr(const char __user *pathname, char __user *list, |
662 | size_t size, unsigned int lookup_flags) | |
1da177e4 | 663 | { |
2d8f3038 | 664 | struct path path; |
1da177e4 | 665 | ssize_t error; |
10a90cf3 JL |
666 | retry: |
667 | error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); | |
1da177e4 LT |
668 | if (error) |
669 | return error; | |
2d8f3038 AV |
670 | error = listxattr(path.dentry, list, size); |
671 | path_put(&path); | |
10a90cf3 JL |
672 | if (retry_estale(error, lookup_flags)) { |
673 | lookup_flags |= LOOKUP_REVAL; | |
674 | goto retry; | |
675 | } | |
1da177e4 LT |
676 | return error; |
677 | } | |
678 | ||
8cc43116 EB |
679 | SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list, |
680 | size_t, size) | |
681 | { | |
682 | return path_listxattr(pathname, list, size, LOOKUP_FOLLOW); | |
683 | } | |
684 | ||
64fd1de3 HC |
685 | SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list, |
686 | size_t, size) | |
1da177e4 | 687 | { |
8cc43116 | 688 | return path_listxattr(pathname, list, size, 0); |
1da177e4 LT |
689 | } |
690 | ||
64fd1de3 | 691 | SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size) |
1da177e4 | 692 | { |
2903ff01 | 693 | struct fd f = fdget(fd); |
1da177e4 LT |
694 | ssize_t error = -EBADF; |
695 | ||
2903ff01 | 696 | if (!f.file) |
1da177e4 | 697 | return error; |
9f45f5bf | 698 | audit_file(f.file); |
2903ff01 AV |
699 | error = listxattr(f.file->f_path.dentry, list, size); |
700 | fdput(f); | |
1da177e4 LT |
701 | return error; |
702 | } | |
703 | ||
704 | /* | |
705 | * Extended attribute REMOVE operations | |
706 | */ | |
707 | static long | |
8f0cfa52 | 708 | removexattr(struct dentry *d, const char __user *name) |
1da177e4 LT |
709 | { |
710 | int error; | |
711 | char kname[XATTR_NAME_MAX + 1]; | |
712 | ||
713 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
714 | if (error == 0 || error == sizeof(kname)) | |
715 | error = -ERANGE; | |
716 | if (error < 0) | |
717 | return error; | |
718 | ||
5be196e5 | 719 | return vfs_removexattr(d, kname); |
1da177e4 LT |
720 | } |
721 | ||
8cc43116 EB |
722 | static int path_removexattr(const char __user *pathname, |
723 | const char __user *name, unsigned int lookup_flags) | |
1da177e4 | 724 | { |
2d8f3038 | 725 | struct path path; |
1da177e4 | 726 | int error; |
12f06212 JL |
727 | retry: |
728 | error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); | |
1da177e4 LT |
729 | if (error) |
730 | return error; | |
2d8f3038 | 731 | error = mnt_want_write(path.mnt); |
18f335af | 732 | if (!error) { |
2d8f3038 AV |
733 | error = removexattr(path.dentry, name); |
734 | mnt_drop_write(path.mnt); | |
18f335af | 735 | } |
2d8f3038 | 736 | path_put(&path); |
12f06212 JL |
737 | if (retry_estale(error, lookup_flags)) { |
738 | lookup_flags |= LOOKUP_REVAL; | |
739 | goto retry; | |
740 | } | |
1da177e4 LT |
741 | return error; |
742 | } | |
743 | ||
8cc43116 EB |
744 | SYSCALL_DEFINE2(removexattr, const char __user *, pathname, |
745 | const char __user *, name) | |
746 | { | |
747 | return path_removexattr(pathname, name, LOOKUP_FOLLOW); | |
748 | } | |
749 | ||
6a6160a7 HC |
750 | SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname, |
751 | const char __user *, name) | |
1da177e4 | 752 | { |
8cc43116 | 753 | return path_removexattr(pathname, name, 0); |
1da177e4 LT |
754 | } |
755 | ||
6a6160a7 | 756 | SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name) |
1da177e4 | 757 | { |
2903ff01 | 758 | struct fd f = fdget(fd); |
1da177e4 LT |
759 | int error = -EBADF; |
760 | ||
2903ff01 | 761 | if (!f.file) |
1da177e4 | 762 | return error; |
9f45f5bf | 763 | audit_file(f.file); |
2903ff01 | 764 | error = mnt_want_write_file(f.file); |
18f335af | 765 | if (!error) { |
9f45f5bf | 766 | error = removexattr(f.file->f_path.dentry, name); |
2903ff01 | 767 | mnt_drop_write_file(f.file); |
18f335af | 768 | } |
2903ff01 | 769 | fdput(f); |
1da177e4 LT |
770 | return error; |
771 | } | |
772 | ||
1da177e4 LT |
773 | /* |
774 | * Combine the results of the list() operation from every xattr_handler in the | |
775 | * list. | |
776 | */ | |
777 | ssize_t | |
778 | generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) | |
779 | { | |
bb435453 | 780 | const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr; |
1da177e4 LT |
781 | unsigned int size = 0; |
782 | ||
783 | if (!buffer) { | |
431547b3 | 784 | for_each_xattr_handler(handlers, handler) { |
764a5c6b AG |
785 | if (!handler->name || |
786 | (handler->list && !handler->list(dentry))) | |
c4803c49 | 787 | continue; |
764a5c6b | 788 | size += strlen(handler->name) + 1; |
431547b3 | 789 | } |
1da177e4 LT |
790 | } else { |
791 | char *buf = buffer; | |
764a5c6b | 792 | size_t len; |
1da177e4 LT |
793 | |
794 | for_each_xattr_handler(handlers, handler) { | |
764a5c6b AG |
795 | if (!handler->name || |
796 | (handler->list && !handler->list(dentry))) | |
c4803c49 | 797 | continue; |
764a5c6b AG |
798 | len = strlen(handler->name); |
799 | if (len + 1 > buffer_size) | |
1da177e4 | 800 | return -ERANGE; |
764a5c6b AG |
801 | memcpy(buf, handler->name, len + 1); |
802 | buf += len + 1; | |
803 | buffer_size -= len + 1; | |
1da177e4 LT |
804 | } |
805 | size = buf - buffer; | |
806 | } | |
807 | return size; | |
808 | } | |
1da177e4 | 809 | EXPORT_SYMBOL(generic_listxattr); |
38f38657 | 810 | |
e409de99 AG |
811 | /** |
812 | * xattr_full_name - Compute full attribute name from suffix | |
813 | * | |
814 | * @handler: handler of the xattr_handler operation | |
815 | * @name: name passed to the xattr_handler operation | |
816 | * | |
817 | * The get and set xattr handler operations are called with the remainder of | |
818 | * the attribute name after skipping the handler's prefix: for example, "foo" | |
819 | * is passed to the get operation of a handler with prefix "user." to get | |
820 | * attribute "user.foo". The full name is still "there" in the name though. | |
821 | * | |
822 | * Note: the list xattr handler operation when called from the vfs is passed a | |
823 | * NULL name; some file systems use this operation internally, with varying | |
824 | * semantics. | |
825 | */ | |
826 | const char *xattr_full_name(const struct xattr_handler *handler, | |
827 | const char *name) | |
828 | { | |
98e9cb57 | 829 | size_t prefix_len = strlen(xattr_prefix(handler)); |
e409de99 AG |
830 | |
831 | return name - prefix_len; | |
832 | } | |
833 | EXPORT_SYMBOL(xattr_full_name); | |
834 | ||
38f38657 AR |
835 | /* |
836 | * Allocate new xattr and copy in the value; but leave the name to callers. | |
837 | */ | |
838 | struct simple_xattr *simple_xattr_alloc(const void *value, size_t size) | |
839 | { | |
840 | struct simple_xattr *new_xattr; | |
841 | size_t len; | |
842 | ||
843 | /* wrap around? */ | |
844 | len = sizeof(*new_xattr) + size; | |
4e66d445 | 845 | if (len < sizeof(*new_xattr)) |
38f38657 AR |
846 | return NULL; |
847 | ||
848 | new_xattr = kmalloc(len, GFP_KERNEL); | |
849 | if (!new_xattr) | |
850 | return NULL; | |
851 | ||
852 | new_xattr->size = size; | |
853 | memcpy(new_xattr->value, value, size); | |
854 | return new_xattr; | |
855 | } | |
856 | ||
857 | /* | |
858 | * xattr GET operation for in-memory/pseudo filesystems | |
859 | */ | |
860 | int simple_xattr_get(struct simple_xattrs *xattrs, const char *name, | |
861 | void *buffer, size_t size) | |
862 | { | |
863 | struct simple_xattr *xattr; | |
864 | int ret = -ENODATA; | |
865 | ||
866 | spin_lock(&xattrs->lock); | |
867 | list_for_each_entry(xattr, &xattrs->head, list) { | |
868 | if (strcmp(name, xattr->name)) | |
869 | continue; | |
870 | ||
871 | ret = xattr->size; | |
872 | if (buffer) { | |
873 | if (size < xattr->size) | |
874 | ret = -ERANGE; | |
875 | else | |
876 | memcpy(buffer, xattr->value, xattr->size); | |
877 | } | |
878 | break; | |
879 | } | |
880 | spin_unlock(&xattrs->lock); | |
881 | return ret; | |
882 | } | |
883 | ||
aa7c5241 AG |
884 | /** |
885 | * simple_xattr_set - xattr SET operation for in-memory/pseudo filesystems | |
886 | * @xattrs: target simple_xattr list | |
887 | * @name: name of the extended attribute | |
888 | * @value: value of the xattr. If %NULL, will remove the attribute. | |
889 | * @size: size of the new xattr | |
890 | * @flags: %XATTR_{CREATE|REPLACE} | |
891 | * | |
892 | * %XATTR_CREATE is set, the xattr shouldn't exist already; otherwise fails | |
893 | * with -EEXIST. If %XATTR_REPLACE is set, the xattr should exist; | |
894 | * otherwise, fails with -ENODATA. | |
895 | * | |
896 | * Returns 0 on success, -errno on failure. | |
897 | */ | |
898 | int simple_xattr_set(struct simple_xattrs *xattrs, const char *name, | |
899 | const void *value, size_t size, int flags) | |
38f38657 AR |
900 | { |
901 | struct simple_xattr *xattr; | |
43385846 | 902 | struct simple_xattr *new_xattr = NULL; |
38f38657 AR |
903 | int err = 0; |
904 | ||
905 | /* value == NULL means remove */ | |
906 | if (value) { | |
907 | new_xattr = simple_xattr_alloc(value, size); | |
908 | if (!new_xattr) | |
909 | return -ENOMEM; | |
910 | ||
911 | new_xattr->name = kstrdup(name, GFP_KERNEL); | |
912 | if (!new_xattr->name) { | |
913 | kfree(new_xattr); | |
914 | return -ENOMEM; | |
915 | } | |
916 | } | |
917 | ||
918 | spin_lock(&xattrs->lock); | |
919 | list_for_each_entry(xattr, &xattrs->head, list) { | |
920 | if (!strcmp(name, xattr->name)) { | |
921 | if (flags & XATTR_CREATE) { | |
922 | xattr = new_xattr; | |
923 | err = -EEXIST; | |
924 | } else if (new_xattr) { | |
925 | list_replace(&xattr->list, &new_xattr->list); | |
926 | } else { | |
927 | list_del(&xattr->list); | |
928 | } | |
929 | goto out; | |
930 | } | |
931 | } | |
932 | if (flags & XATTR_REPLACE) { | |
933 | xattr = new_xattr; | |
934 | err = -ENODATA; | |
935 | } else { | |
936 | list_add(&new_xattr->list, &xattrs->head); | |
937 | xattr = NULL; | |
938 | } | |
939 | out: | |
940 | spin_unlock(&xattrs->lock); | |
941 | if (xattr) { | |
942 | kfree(xattr->name); | |
943 | kfree(xattr); | |
944 | } | |
945 | return err; | |
946 | ||
947 | } | |
948 | ||
38f38657 AR |
949 | static bool xattr_is_trusted(const char *name) |
950 | { | |
951 | return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN); | |
952 | } | |
953 | ||
786534b9 AG |
954 | static int xattr_list_one(char **buffer, ssize_t *remaining_size, |
955 | const char *name) | |
956 | { | |
957 | size_t len = strlen(name) + 1; | |
958 | if (*buffer) { | |
959 | if (*remaining_size < len) | |
960 | return -ERANGE; | |
961 | memcpy(*buffer, name, len); | |
962 | *buffer += len; | |
963 | } | |
964 | *remaining_size -= len; | |
965 | return 0; | |
966 | } | |
967 | ||
38f38657 AR |
968 | /* |
969 | * xattr LIST operation for in-memory/pseudo filesystems | |
970 | */ | |
786534b9 AG |
971 | ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs, |
972 | char *buffer, size_t size) | |
38f38657 AR |
973 | { |
974 | bool trusted = capable(CAP_SYS_ADMIN); | |
975 | struct simple_xattr *xattr; | |
786534b9 | 976 | ssize_t remaining_size = size; |
0e9a7da5 | 977 | int err = 0; |
786534b9 AG |
978 | |
979 | #ifdef CONFIG_FS_POSIX_ACL | |
980 | if (inode->i_acl) { | |
981 | err = xattr_list_one(&buffer, &remaining_size, | |
982 | XATTR_NAME_POSIX_ACL_ACCESS); | |
983 | if (err) | |
984 | return err; | |
985 | } | |
986 | if (inode->i_default_acl) { | |
987 | err = xattr_list_one(&buffer, &remaining_size, | |
988 | XATTR_NAME_POSIX_ACL_DEFAULT); | |
989 | if (err) | |
990 | return err; | |
991 | } | |
992 | #endif | |
38f38657 AR |
993 | |
994 | spin_lock(&xattrs->lock); | |
995 | list_for_each_entry(xattr, &xattrs->head, list) { | |
38f38657 AR |
996 | /* skip "trusted." attributes for unprivileged callers */ |
997 | if (!trusted && xattr_is_trusted(xattr->name)) | |
998 | continue; | |
999 | ||
786534b9 AG |
1000 | err = xattr_list_one(&buffer, &remaining_size, xattr->name); |
1001 | if (err) | |
0e9a7da5 | 1002 | break; |
38f38657 AR |
1003 | } |
1004 | spin_unlock(&xattrs->lock); | |
1005 | ||
0e9a7da5 | 1006 | return err ? err : size - remaining_size; |
38f38657 AR |
1007 | } |
1008 | ||
4895768b AR |
1009 | /* |
1010 | * Adds an extended attribute to the list | |
1011 | */ | |
38f38657 AR |
1012 | void simple_xattr_list_add(struct simple_xattrs *xattrs, |
1013 | struct simple_xattr *new_xattr) | |
1014 | { | |
1015 | spin_lock(&xattrs->lock); | |
1016 | list_add(&new_xattr->list, &xattrs->head); | |
1017 | spin_unlock(&xattrs->lock); | |
1018 | } |