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Commit | Line | Data |
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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 | } | |
300 | ||
5d6c3191 AG |
301 | ssize_t |
302 | __vfs_getxattr(struct dentry *dentry, struct inode *inode, const char *name, | |
303 | void *value, size_t size) | |
304 | { | |
6c6ef9f2 AG |
305 | const struct xattr_handler *handler; |
306 | ||
307 | handler = xattr_resolve_name(inode, &name); | |
308 | if (IS_ERR(handler)) | |
309 | return PTR_ERR(handler); | |
310 | if (!handler->get) | |
5d6c3191 | 311 | return -EOPNOTSUPP; |
6c6ef9f2 | 312 | return handler->get(handler, dentry, inode, name, value, size); |
5d6c3191 AG |
313 | } |
314 | EXPORT_SYMBOL(__vfs_getxattr); | |
315 | ||
5be196e5 | 316 | ssize_t |
8f0cfa52 | 317 | vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size) |
5be196e5 CH |
318 | { |
319 | struct inode *inode = dentry->d_inode; | |
320 | int error; | |
321 | ||
e0ad7b07 | 322 | error = xattr_permission(inode, name, MAY_READ); |
323 | if (error) | |
324 | return error; | |
325 | ||
5be196e5 CH |
326 | error = security_inode_getxattr(dentry, name); |
327 | if (error) | |
328 | return error; | |
329 | ||
5be196e5 | 330 | if (!strncmp(name, XATTR_SECURITY_PREFIX, |
e0ad7b07 | 331 | XATTR_SECURITY_PREFIX_LEN)) { |
332 | const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; | |
42492594 | 333 | int ret = xattr_getsecurity(inode, suffix, value, size); |
5be196e5 CH |
334 | /* |
335 | * Only overwrite the return value if a security module | |
336 | * is actually active. | |
337 | */ | |
4bea5805 DQ |
338 | if (ret == -EOPNOTSUPP) |
339 | goto nolsm; | |
340 | return ret; | |
5be196e5 | 341 | } |
4bea5805 | 342 | nolsm: |
5d6c3191 | 343 | return __vfs_getxattr(dentry, inode, name, value, size); |
5be196e5 CH |
344 | } |
345 | EXPORT_SYMBOL_GPL(vfs_getxattr); | |
346 | ||
659564c8 | 347 | ssize_t |
bf3ee713 | 348 | vfs_listxattr(struct dentry *dentry, char *list, size_t size) |
659564c8 | 349 | { |
bf3ee713 | 350 | struct inode *inode = d_inode(dentry); |
659564c8 BN |
351 | ssize_t error; |
352 | ||
bf3ee713 | 353 | error = security_inode_listxattr(dentry); |
659564c8 BN |
354 | if (error) |
355 | return error; | |
bf3ee713 AG |
356 | if (inode->i_op->listxattr && (inode->i_opflags & IOP_XATTR)) { |
357 | error = -EOPNOTSUPP; | |
358 | error = inode->i_op->listxattr(dentry, list, size); | |
659564c8 | 359 | } else { |
bf3ee713 | 360 | error = security_inode_listsecurity(inode, list, size); |
659564c8 BN |
361 | if (size && error > size) |
362 | error = -ERANGE; | |
363 | } | |
364 | return error; | |
365 | } | |
366 | EXPORT_SYMBOL_GPL(vfs_listxattr); | |
367 | ||
5be196e5 | 368 | int |
5d6c3191 | 369 | __vfs_removexattr(struct dentry *dentry, const char *name) |
5be196e5 | 370 | { |
6c6ef9f2 AG |
371 | struct inode *inode = d_inode(dentry); |
372 | const struct xattr_handler *handler; | |
5be196e5 | 373 | |
6c6ef9f2 AG |
374 | handler = xattr_resolve_name(inode, &name); |
375 | if (IS_ERR(handler)) | |
376 | return PTR_ERR(handler); | |
377 | if (!handler->set) | |
5be196e5 | 378 | return -EOPNOTSUPP; |
6c6ef9f2 | 379 | return handler->set(handler, dentry, inode, name, NULL, 0, XATTR_REPLACE); |
5d6c3191 AG |
380 | } |
381 | EXPORT_SYMBOL(__vfs_removexattr); | |
382 | ||
25b33138 SF |
383 | /** |
384 | * __vfs_removexattr_noperm - perform removexattr operation without | |
385 | * performing permission checks. | |
386 | * | |
387 | * @dentry - object to perform setxattr on | |
388 | * @name - xattr name to set | |
389 | * | |
390 | * returns the result of the internal setxattr or setsecurity operations. | |
391 | * | |
392 | * This function requires the caller to lock the inode's i_mutex before it | |
393 | * is executed. It also assumes that the caller will make the appropriate | |
394 | * permission checks. | |
395 | */ | |
396 | int | |
397 | __vfs_removexattr_noperm(struct dentry *dentry, const char *name) | |
398 | { | |
399 | int error; | |
400 | ||
401 | error =__vfs_removexattr(dentry, name); | |
402 | if (!error) { | |
403 | fsnotify_xattr(dentry); | |
404 | evm_inode_post_removexattr(dentry, name); | |
405 | } | |
406 | return error; | |
407 | } | |
408 | EXPORT_SYMBOL_GPL(__vfs_removexattr_noperm); | |
409 | ||
5d6c3191 AG |
410 | int |
411 | vfs_removexattr(struct dentry *dentry, const char *name) | |
412 | { | |
413 | struct inode *inode = dentry->d_inode; | |
414 | int error; | |
5be196e5 | 415 | |
e0ad7b07 | 416 | error = xattr_permission(inode, name, MAY_WRITE); |
417 | if (error) | |
418 | return error; | |
419 | ||
5955102c | 420 | inode_lock(inode); |
5be196e5 | 421 | error = security_inode_removexattr(dentry, name); |
7c51bb00 DK |
422 | if (error) |
423 | goto out; | |
5be196e5 | 424 | |
25b33138 | 425 | error = __vfs_removexattr_noperm(dentry, name); |
7c51bb00 DK |
426 | |
427 | out: | |
5955102c | 428 | inode_unlock(inode); |
5be196e5 CH |
429 | return error; |
430 | } | |
431 | EXPORT_SYMBOL_GPL(vfs_removexattr); | |
432 | ||
433 | ||
1da177e4 LT |
434 | /* |
435 | * Extended attribute SET operations | |
436 | */ | |
437 | static long | |
8f0cfa52 | 438 | setxattr(struct dentry *d, const char __user *name, const void __user *value, |
1da177e4 LT |
439 | size_t size, int flags) |
440 | { | |
441 | int error; | |
442 | void *kvalue = NULL; | |
443 | char kname[XATTR_NAME_MAX + 1]; | |
444 | ||
445 | if (flags & ~(XATTR_CREATE|XATTR_REPLACE)) | |
446 | return -EINVAL; | |
447 | ||
448 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
449 | if (error == 0 || error == sizeof(kname)) | |
450 | error = -ERANGE; | |
451 | if (error < 0) | |
452 | return error; | |
453 | ||
454 | if (size) { | |
455 | if (size > XATTR_SIZE_MAX) | |
456 | return -E2BIG; | |
44c82498 AM |
457 | kvalue = kmalloc(size, GFP_KERNEL | __GFP_NOWARN); |
458 | if (!kvalue) { | |
0b2a6f23 RW |
459 | kvalue = vmalloc(size); |
460 | if (!kvalue) | |
44c82498 | 461 | return -ENOMEM; |
44c82498 AM |
462 | } |
463 | if (copy_from_user(kvalue, value, size)) { | |
464 | error = -EFAULT; | |
465 | goto out; | |
466 | } | |
2f6f0654 EB |
467 | if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) || |
468 | (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)) | |
469 | posix_acl_fix_xattr_from_user(kvalue, size); | |
1da177e4 LT |
470 | } |
471 | ||
5be196e5 | 472 | error = vfs_setxattr(d, kname, kvalue, size, flags); |
44c82498 | 473 | out: |
0b2a6f23 RW |
474 | kvfree(kvalue); |
475 | ||
1da177e4 LT |
476 | return error; |
477 | } | |
478 | ||
8cc43116 EB |
479 | static int path_setxattr(const char __user *pathname, |
480 | const char __user *name, const void __user *value, | |
481 | size_t size, int flags, unsigned int lookup_flags) | |
1da177e4 | 482 | { |
2d8f3038 | 483 | struct path path; |
1da177e4 | 484 | int error; |
68f1bb8b JL |
485 | retry: |
486 | error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); | |
1da177e4 LT |
487 | if (error) |
488 | return error; | |
2d8f3038 | 489 | error = mnt_want_write(path.mnt); |
18f335af | 490 | if (!error) { |
2d8f3038 AV |
491 | error = setxattr(path.dentry, name, value, size, flags); |
492 | mnt_drop_write(path.mnt); | |
18f335af | 493 | } |
2d8f3038 | 494 | path_put(&path); |
68f1bb8b JL |
495 | if (retry_estale(error, lookup_flags)) { |
496 | lookup_flags |= LOOKUP_REVAL; | |
497 | goto retry; | |
498 | } | |
1da177e4 LT |
499 | return error; |
500 | } | |
501 | ||
8cc43116 EB |
502 | SYSCALL_DEFINE5(setxattr, const char __user *, pathname, |
503 | const char __user *, name, const void __user *, value, | |
504 | size_t, size, int, flags) | |
505 | { | |
506 | return path_setxattr(pathname, name, value, size, flags, LOOKUP_FOLLOW); | |
507 | } | |
508 | ||
64fd1de3 HC |
509 | SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname, |
510 | const char __user *, name, const void __user *, value, | |
511 | size_t, size, int, flags) | |
1da177e4 | 512 | { |
8cc43116 | 513 | return path_setxattr(pathname, name, value, size, flags, 0); |
1da177e4 LT |
514 | } |
515 | ||
64fd1de3 HC |
516 | SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name, |
517 | const void __user *,value, size_t, size, int, flags) | |
1da177e4 | 518 | { |
2903ff01 | 519 | struct fd f = fdget(fd); |
1da177e4 LT |
520 | int error = -EBADF; |
521 | ||
2903ff01 | 522 | if (!f.file) |
1da177e4 | 523 | return error; |
9f45f5bf | 524 | audit_file(f.file); |
2903ff01 | 525 | error = mnt_want_write_file(f.file); |
18f335af | 526 | if (!error) { |
9f45f5bf | 527 | error = setxattr(f.file->f_path.dentry, name, value, size, flags); |
2903ff01 | 528 | mnt_drop_write_file(f.file); |
18f335af | 529 | } |
2903ff01 | 530 | fdput(f); |
1da177e4 LT |
531 | return error; |
532 | } | |
533 | ||
534 | /* | |
535 | * Extended attribute GET operations | |
536 | */ | |
537 | static ssize_t | |
8f0cfa52 DH |
538 | getxattr(struct dentry *d, const char __user *name, void __user *value, |
539 | size_t size) | |
1da177e4 LT |
540 | { |
541 | ssize_t error; | |
542 | void *kvalue = NULL; | |
543 | char kname[XATTR_NAME_MAX + 1]; | |
544 | ||
545 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
546 | if (error == 0 || error == sizeof(kname)) | |
547 | error = -ERANGE; | |
548 | if (error < 0) | |
549 | return error; | |
550 | ||
551 | if (size) { | |
552 | if (size > XATTR_SIZE_MAX) | |
553 | size = XATTR_SIZE_MAX; | |
779302e6 SL |
554 | kvalue = kzalloc(size, GFP_KERNEL | __GFP_NOWARN); |
555 | if (!kvalue) { | |
0b2a6f23 RW |
556 | kvalue = vmalloc(size); |
557 | if (!kvalue) | |
779302e6 | 558 | return -ENOMEM; |
779302e6 | 559 | } |
1da177e4 LT |
560 | } |
561 | ||
5be196e5 | 562 | error = vfs_getxattr(d, kname, kvalue, size); |
f549d6c1 | 563 | if (error > 0) { |
2f6f0654 EB |
564 | if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) || |
565 | (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)) | |
566 | posix_acl_fix_xattr_to_user(kvalue, size); | |
f549d6c1 SS |
567 | if (size && copy_to_user(value, kvalue, error)) |
568 | error = -EFAULT; | |
569 | } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) { | |
570 | /* The file system tried to returned a value bigger | |
571 | than XATTR_SIZE_MAX bytes. Not possible. */ | |
572 | error = -E2BIG; | |
1da177e4 | 573 | } |
0b2a6f23 RW |
574 | |
575 | kvfree(kvalue); | |
576 | ||
1da177e4 LT |
577 | return error; |
578 | } | |
579 | ||
8cc43116 EB |
580 | static ssize_t path_getxattr(const char __user *pathname, |
581 | const char __user *name, void __user *value, | |
582 | size_t size, unsigned int lookup_flags) | |
1da177e4 | 583 | { |
2d8f3038 | 584 | struct path path; |
1da177e4 | 585 | ssize_t error; |
60e66b48 JL |
586 | retry: |
587 | error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); | |
1da177e4 LT |
588 | if (error) |
589 | return error; | |
2d8f3038 AV |
590 | error = getxattr(path.dentry, name, value, size); |
591 | path_put(&path); | |
60e66b48 JL |
592 | if (retry_estale(error, lookup_flags)) { |
593 | lookup_flags |= LOOKUP_REVAL; | |
594 | goto retry; | |
595 | } | |
1da177e4 LT |
596 | return error; |
597 | } | |
598 | ||
8cc43116 EB |
599 | SYSCALL_DEFINE4(getxattr, const char __user *, pathname, |
600 | const char __user *, name, void __user *, value, size_t, size) | |
601 | { | |
602 | return path_getxattr(pathname, name, value, size, LOOKUP_FOLLOW); | |
603 | } | |
604 | ||
64fd1de3 HC |
605 | SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname, |
606 | const char __user *, name, void __user *, value, size_t, size) | |
1da177e4 | 607 | { |
8cc43116 | 608 | return path_getxattr(pathname, name, value, size, 0); |
1da177e4 LT |
609 | } |
610 | ||
64fd1de3 HC |
611 | SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name, |
612 | void __user *, value, size_t, size) | |
1da177e4 | 613 | { |
2903ff01 | 614 | struct fd f = fdget(fd); |
1da177e4 LT |
615 | ssize_t error = -EBADF; |
616 | ||
2903ff01 | 617 | if (!f.file) |
1da177e4 | 618 | return error; |
9f45f5bf | 619 | audit_file(f.file); |
2903ff01 AV |
620 | error = getxattr(f.file->f_path.dentry, name, value, size); |
621 | fdput(f); | |
1da177e4 LT |
622 | return error; |
623 | } | |
624 | ||
625 | /* | |
626 | * Extended attribute LIST operations | |
627 | */ | |
628 | static ssize_t | |
629 | listxattr(struct dentry *d, char __user *list, size_t size) | |
630 | { | |
631 | ssize_t error; | |
632 | char *klist = NULL; | |
633 | ||
634 | if (size) { | |
635 | if (size > XATTR_LIST_MAX) | |
636 | size = XATTR_LIST_MAX; | |
703bf2d1 | 637 | klist = kmalloc(size, __GFP_NOWARN | GFP_KERNEL); |
0d08d7b7 | 638 | if (!klist) { |
0b2a6f23 RW |
639 | klist = vmalloc(size); |
640 | if (!klist) | |
0d08d7b7 | 641 | return -ENOMEM; |
0d08d7b7 | 642 | } |
1da177e4 LT |
643 | } |
644 | ||
659564c8 | 645 | error = vfs_listxattr(d, klist, size); |
f549d6c1 SS |
646 | if (error > 0) { |
647 | if (size && copy_to_user(list, klist, error)) | |
648 | error = -EFAULT; | |
649 | } else if (error == -ERANGE && size >= XATTR_LIST_MAX) { | |
650 | /* The file system tried to returned a list bigger | |
651 | than XATTR_LIST_MAX bytes. Not possible. */ | |
652 | error = -E2BIG; | |
1da177e4 | 653 | } |
0b2a6f23 RW |
654 | |
655 | kvfree(klist); | |
656 | ||
1da177e4 LT |
657 | return error; |
658 | } | |
659 | ||
8cc43116 EB |
660 | static ssize_t path_listxattr(const char __user *pathname, char __user *list, |
661 | size_t size, unsigned int lookup_flags) | |
1da177e4 | 662 | { |
2d8f3038 | 663 | struct path path; |
1da177e4 | 664 | ssize_t error; |
10a90cf3 JL |
665 | retry: |
666 | error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); | |
1da177e4 LT |
667 | if (error) |
668 | return error; | |
2d8f3038 AV |
669 | error = listxattr(path.dentry, list, size); |
670 | path_put(&path); | |
10a90cf3 JL |
671 | if (retry_estale(error, lookup_flags)) { |
672 | lookup_flags |= LOOKUP_REVAL; | |
673 | goto retry; | |
674 | } | |
1da177e4 LT |
675 | return error; |
676 | } | |
677 | ||
8cc43116 EB |
678 | SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list, |
679 | size_t, size) | |
680 | { | |
681 | return path_listxattr(pathname, list, size, LOOKUP_FOLLOW); | |
682 | } | |
683 | ||
64fd1de3 HC |
684 | SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list, |
685 | size_t, size) | |
1da177e4 | 686 | { |
8cc43116 | 687 | return path_listxattr(pathname, list, size, 0); |
1da177e4 LT |
688 | } |
689 | ||
64fd1de3 | 690 | SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size) |
1da177e4 | 691 | { |
2903ff01 | 692 | struct fd f = fdget(fd); |
1da177e4 LT |
693 | ssize_t error = -EBADF; |
694 | ||
2903ff01 | 695 | if (!f.file) |
1da177e4 | 696 | return error; |
9f45f5bf | 697 | audit_file(f.file); |
2903ff01 AV |
698 | error = listxattr(f.file->f_path.dentry, list, size); |
699 | fdput(f); | |
1da177e4 LT |
700 | return error; |
701 | } | |
702 | ||
703 | /* | |
704 | * Extended attribute REMOVE operations | |
705 | */ | |
706 | static long | |
8f0cfa52 | 707 | removexattr(struct dentry *d, const char __user *name) |
1da177e4 LT |
708 | { |
709 | int error; | |
710 | char kname[XATTR_NAME_MAX + 1]; | |
711 | ||
712 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
713 | if (error == 0 || error == sizeof(kname)) | |
714 | error = -ERANGE; | |
715 | if (error < 0) | |
716 | return error; | |
717 | ||
5be196e5 | 718 | return vfs_removexattr(d, kname); |
1da177e4 LT |
719 | } |
720 | ||
8cc43116 EB |
721 | static int path_removexattr(const char __user *pathname, |
722 | const char __user *name, unsigned int lookup_flags) | |
1da177e4 | 723 | { |
2d8f3038 | 724 | struct path path; |
1da177e4 | 725 | int error; |
12f06212 JL |
726 | retry: |
727 | error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); | |
1da177e4 LT |
728 | if (error) |
729 | return error; | |
2d8f3038 | 730 | error = mnt_want_write(path.mnt); |
18f335af | 731 | if (!error) { |
2d8f3038 AV |
732 | error = removexattr(path.dentry, name); |
733 | mnt_drop_write(path.mnt); | |
18f335af | 734 | } |
2d8f3038 | 735 | path_put(&path); |
12f06212 JL |
736 | if (retry_estale(error, lookup_flags)) { |
737 | lookup_flags |= LOOKUP_REVAL; | |
738 | goto retry; | |
739 | } | |
1da177e4 LT |
740 | return error; |
741 | } | |
742 | ||
8cc43116 EB |
743 | SYSCALL_DEFINE2(removexattr, const char __user *, pathname, |
744 | const char __user *, name) | |
745 | { | |
746 | return path_removexattr(pathname, name, LOOKUP_FOLLOW); | |
747 | } | |
748 | ||
6a6160a7 HC |
749 | SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname, |
750 | const char __user *, name) | |
1da177e4 | 751 | { |
8cc43116 | 752 | return path_removexattr(pathname, name, 0); |
1da177e4 LT |
753 | } |
754 | ||
6a6160a7 | 755 | SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name) |
1da177e4 | 756 | { |
2903ff01 | 757 | struct fd f = fdget(fd); |
1da177e4 LT |
758 | int error = -EBADF; |
759 | ||
2903ff01 | 760 | if (!f.file) |
1da177e4 | 761 | return error; |
9f45f5bf | 762 | audit_file(f.file); |
2903ff01 | 763 | error = mnt_want_write_file(f.file); |
18f335af | 764 | if (!error) { |
9f45f5bf | 765 | error = removexattr(f.file->f_path.dentry, name); |
2903ff01 | 766 | mnt_drop_write_file(f.file); |
18f335af | 767 | } |
2903ff01 | 768 | fdput(f); |
1da177e4 LT |
769 | return error; |
770 | } | |
771 | ||
1da177e4 LT |
772 | /* |
773 | * Combine the results of the list() operation from every xattr_handler in the | |
774 | * list. | |
775 | */ | |
776 | ssize_t | |
777 | generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) | |
778 | { | |
bb435453 | 779 | const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr; |
1da177e4 LT |
780 | unsigned int size = 0; |
781 | ||
782 | if (!buffer) { | |
431547b3 | 783 | for_each_xattr_handler(handlers, handler) { |
764a5c6b AG |
784 | if (!handler->name || |
785 | (handler->list && !handler->list(dentry))) | |
c4803c49 | 786 | continue; |
764a5c6b | 787 | size += strlen(handler->name) + 1; |
431547b3 | 788 | } |
1da177e4 LT |
789 | } else { |
790 | char *buf = buffer; | |
764a5c6b | 791 | size_t len; |
1da177e4 LT |
792 | |
793 | for_each_xattr_handler(handlers, handler) { | |
764a5c6b AG |
794 | if (!handler->name || |
795 | (handler->list && !handler->list(dentry))) | |
c4803c49 | 796 | continue; |
764a5c6b AG |
797 | len = strlen(handler->name); |
798 | if (len + 1 > buffer_size) | |
1da177e4 | 799 | return -ERANGE; |
764a5c6b AG |
800 | memcpy(buf, handler->name, len + 1); |
801 | buf += len + 1; | |
802 | buffer_size -= len + 1; | |
1da177e4 LT |
803 | } |
804 | size = buf - buffer; | |
805 | } | |
806 | return size; | |
807 | } | |
1da177e4 | 808 | EXPORT_SYMBOL(generic_listxattr); |
38f38657 | 809 | |
e409de99 AG |
810 | /** |
811 | * xattr_full_name - Compute full attribute name from suffix | |
812 | * | |
813 | * @handler: handler of the xattr_handler operation | |
814 | * @name: name passed to the xattr_handler operation | |
815 | * | |
816 | * The get and set xattr handler operations are called with the remainder of | |
817 | * the attribute name after skipping the handler's prefix: for example, "foo" | |
818 | * is passed to the get operation of a handler with prefix "user." to get | |
819 | * attribute "user.foo". The full name is still "there" in the name though. | |
820 | * | |
821 | * Note: the list xattr handler operation when called from the vfs is passed a | |
822 | * NULL name; some file systems use this operation internally, with varying | |
823 | * semantics. | |
824 | */ | |
825 | const char *xattr_full_name(const struct xattr_handler *handler, | |
826 | const char *name) | |
827 | { | |
98e9cb57 | 828 | size_t prefix_len = strlen(xattr_prefix(handler)); |
e409de99 AG |
829 | |
830 | return name - prefix_len; | |
831 | } | |
832 | EXPORT_SYMBOL(xattr_full_name); | |
833 | ||
38f38657 AR |
834 | /* |
835 | * Allocate new xattr and copy in the value; but leave the name to callers. | |
836 | */ | |
837 | struct simple_xattr *simple_xattr_alloc(const void *value, size_t size) | |
838 | { | |
839 | struct simple_xattr *new_xattr; | |
840 | size_t len; | |
841 | ||
842 | /* wrap around? */ | |
843 | len = sizeof(*new_xattr) + size; | |
4e66d445 | 844 | if (len < sizeof(*new_xattr)) |
38f38657 AR |
845 | return NULL; |
846 | ||
847 | new_xattr = kmalloc(len, GFP_KERNEL); | |
848 | if (!new_xattr) | |
849 | return NULL; | |
850 | ||
851 | new_xattr->size = size; | |
852 | memcpy(new_xattr->value, value, size); | |
853 | return new_xattr; | |
854 | } | |
855 | ||
856 | /* | |
857 | * xattr GET operation for in-memory/pseudo filesystems | |
858 | */ | |
859 | int simple_xattr_get(struct simple_xattrs *xattrs, const char *name, | |
860 | void *buffer, size_t size) | |
861 | { | |
862 | struct simple_xattr *xattr; | |
863 | int ret = -ENODATA; | |
864 | ||
865 | spin_lock(&xattrs->lock); | |
866 | list_for_each_entry(xattr, &xattrs->head, list) { | |
867 | if (strcmp(name, xattr->name)) | |
868 | continue; | |
869 | ||
870 | ret = xattr->size; | |
871 | if (buffer) { | |
872 | if (size < xattr->size) | |
873 | ret = -ERANGE; | |
874 | else | |
875 | memcpy(buffer, xattr->value, xattr->size); | |
876 | } | |
877 | break; | |
878 | } | |
879 | spin_unlock(&xattrs->lock); | |
880 | return ret; | |
881 | } | |
882 | ||
aa7c5241 AG |
883 | /** |
884 | * simple_xattr_set - xattr SET operation for in-memory/pseudo filesystems | |
885 | * @xattrs: target simple_xattr list | |
886 | * @name: name of the extended attribute | |
887 | * @value: value of the xattr. If %NULL, will remove the attribute. | |
888 | * @size: size of the new xattr | |
889 | * @flags: %XATTR_{CREATE|REPLACE} | |
890 | * | |
891 | * %XATTR_CREATE is set, the xattr shouldn't exist already; otherwise fails | |
892 | * with -EEXIST. If %XATTR_REPLACE is set, the xattr should exist; | |
893 | * otherwise, fails with -ENODATA. | |
894 | * | |
895 | * Returns 0 on success, -errno on failure. | |
896 | */ | |
897 | int simple_xattr_set(struct simple_xattrs *xattrs, const char *name, | |
898 | const void *value, size_t size, int flags) | |
38f38657 AR |
899 | { |
900 | struct simple_xattr *xattr; | |
43385846 | 901 | struct simple_xattr *new_xattr = NULL; |
38f38657 AR |
902 | int err = 0; |
903 | ||
904 | /* value == NULL means remove */ | |
905 | if (value) { | |
906 | new_xattr = simple_xattr_alloc(value, size); | |
907 | if (!new_xattr) | |
908 | return -ENOMEM; | |
909 | ||
910 | new_xattr->name = kstrdup(name, GFP_KERNEL); | |
911 | if (!new_xattr->name) { | |
912 | kfree(new_xattr); | |
913 | return -ENOMEM; | |
914 | } | |
915 | } | |
916 | ||
917 | spin_lock(&xattrs->lock); | |
918 | list_for_each_entry(xattr, &xattrs->head, list) { | |
919 | if (!strcmp(name, xattr->name)) { | |
920 | if (flags & XATTR_CREATE) { | |
921 | xattr = new_xattr; | |
922 | err = -EEXIST; | |
923 | } else if (new_xattr) { | |
924 | list_replace(&xattr->list, &new_xattr->list); | |
925 | } else { | |
926 | list_del(&xattr->list); | |
927 | } | |
928 | goto out; | |
929 | } | |
930 | } | |
931 | if (flags & XATTR_REPLACE) { | |
932 | xattr = new_xattr; | |
933 | err = -ENODATA; | |
934 | } else { | |
935 | list_add(&new_xattr->list, &xattrs->head); | |
936 | xattr = NULL; | |
937 | } | |
938 | out: | |
939 | spin_unlock(&xattrs->lock); | |
940 | if (xattr) { | |
941 | kfree(xattr->name); | |
942 | kfree(xattr); | |
943 | } | |
944 | return err; | |
945 | ||
946 | } | |
947 | ||
38f38657 AR |
948 | static bool xattr_is_trusted(const char *name) |
949 | { | |
950 | return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN); | |
951 | } | |
952 | ||
786534b9 AG |
953 | static int xattr_list_one(char **buffer, ssize_t *remaining_size, |
954 | const char *name) | |
955 | { | |
956 | size_t len = strlen(name) + 1; | |
957 | if (*buffer) { | |
958 | if (*remaining_size < len) | |
959 | return -ERANGE; | |
960 | memcpy(*buffer, name, len); | |
961 | *buffer += len; | |
962 | } | |
963 | *remaining_size -= len; | |
964 | return 0; | |
965 | } | |
966 | ||
38f38657 AR |
967 | /* |
968 | * xattr LIST operation for in-memory/pseudo filesystems | |
969 | */ | |
786534b9 AG |
970 | ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs, |
971 | char *buffer, size_t size) | |
38f38657 AR |
972 | { |
973 | bool trusted = capable(CAP_SYS_ADMIN); | |
974 | struct simple_xattr *xattr; | |
786534b9 | 975 | ssize_t remaining_size = size; |
0e9a7da5 | 976 | int err = 0; |
786534b9 AG |
977 | |
978 | #ifdef CONFIG_FS_POSIX_ACL | |
979 | if (inode->i_acl) { | |
980 | err = xattr_list_one(&buffer, &remaining_size, | |
981 | XATTR_NAME_POSIX_ACL_ACCESS); | |
982 | if (err) | |
983 | return err; | |
984 | } | |
985 | if (inode->i_default_acl) { | |
986 | err = xattr_list_one(&buffer, &remaining_size, | |
987 | XATTR_NAME_POSIX_ACL_DEFAULT); | |
988 | if (err) | |
989 | return err; | |
990 | } | |
991 | #endif | |
38f38657 AR |
992 | |
993 | spin_lock(&xattrs->lock); | |
994 | list_for_each_entry(xattr, &xattrs->head, list) { | |
38f38657 AR |
995 | /* skip "trusted." attributes for unprivileged callers */ |
996 | if (!trusted && xattr_is_trusted(xattr->name)) | |
997 | continue; | |
998 | ||
786534b9 AG |
999 | err = xattr_list_one(&buffer, &remaining_size, xattr->name); |
1000 | if (err) | |
0e9a7da5 | 1001 | break; |
38f38657 AR |
1002 | } |
1003 | spin_unlock(&xattrs->lock); | |
1004 | ||
0e9a7da5 | 1005 | return err ? err : size - remaining_size; |
38f38657 AR |
1006 | } |
1007 | ||
4895768b AR |
1008 | /* |
1009 | * Adds an extended attribute to the list | |
1010 | */ | |
38f38657 AR |
1011 | void simple_xattr_list_add(struct simple_xattrs *xattrs, |
1012 | struct simple_xattr *new_xattr) | |
1013 | { | |
1014 | spin_lock(&xattrs->lock); | |
1015 | list_add(&new_xattr->list, &xattrs->head); | |
1016 | spin_unlock(&xattrs->lock); | |
1017 | } |