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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> |
7c6893e3 | 26 | #include "internal.h" |
5be196e5 | 27 | |
b6ba1177 AG |
28 | static const char * |
29 | strcmp_prefix(const char *a, const char *a_prefix) | |
30 | { | |
31 | while (*a_prefix && *a == *a_prefix) { | |
32 | a++; | |
33 | a_prefix++; | |
34 | } | |
35 | return *a_prefix ? NULL : a; | |
36 | } | |
37 | ||
38 | /* | |
39 | * In order to implement different sets of xattr operations for each xattr | |
6c6ef9f2 AG |
40 | * prefix, a filesystem should create a null-terminated array of struct |
41 | * xattr_handler (one for each prefix) and hang a pointer to it off of the | |
42 | * s_xattr field of the superblock. | |
b6ba1177 AG |
43 | */ |
44 | #define for_each_xattr_handler(handlers, handler) \ | |
45 | if (handlers) \ | |
46 | for ((handler) = *(handlers)++; \ | |
47 | (handler) != NULL; \ | |
48 | (handler) = *(handlers)++) | |
49 | ||
50 | /* | |
51 | * Find the xattr_handler with the matching prefix. | |
52 | */ | |
53 | static const struct xattr_handler * | |
d0a5b995 | 54 | xattr_resolve_name(struct inode *inode, const char **name) |
b6ba1177 | 55 | { |
d0a5b995 | 56 | const struct xattr_handler **handlers = inode->i_sb->s_xattr; |
b6ba1177 AG |
57 | const struct xattr_handler *handler; |
58 | ||
5f6e59ae AG |
59 | if (!(inode->i_opflags & IOP_XATTR)) { |
60 | if (unlikely(is_bad_inode(inode))) | |
61 | return ERR_PTR(-EIO); | |
d0a5b995 | 62 | return ERR_PTR(-EOPNOTSUPP); |
5f6e59ae | 63 | } |
b6ba1177 AG |
64 | for_each_xattr_handler(handlers, handler) { |
65 | const char *n; | |
66 | ||
67 | n = strcmp_prefix(*name, xattr_prefix(handler)); | |
68 | if (n) { | |
69 | if (!handler->prefix ^ !*n) { | |
70 | if (*n) | |
71 | continue; | |
72 | return ERR_PTR(-EINVAL); | |
73 | } | |
74 | *name = n; | |
75 | return handler; | |
76 | } | |
77 | } | |
78 | return ERR_PTR(-EOPNOTSUPP); | |
79 | } | |
80 | ||
e0ad7b07 | 81 | /* |
82 | * Check permissions for extended attribute access. This is a bit complicated | |
83 | * because different namespaces have very different rules. | |
84 | */ | |
85 | static int | |
86 | xattr_permission(struct inode *inode, const char *name, int mask) | |
87 | { | |
88 | /* | |
89 | * We can never set or remove an extended attribute on a read-only | |
90 | * filesystem or on an immutable / append-only inode. | |
91 | */ | |
92 | if (mask & MAY_WRITE) { | |
e0ad7b07 | 93 | if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) |
94 | return -EPERM; | |
0bd23d09 EB |
95 | /* |
96 | * Updating an xattr will likely cause i_uid and i_gid | |
97 | * to be writen back improperly if their true value is | |
98 | * unknown to the vfs. | |
99 | */ | |
100 | if (HAS_UNMAPPED_ID(inode)) | |
101 | return -EPERM; | |
e0ad7b07 | 102 | } |
103 | ||
104 | /* | |
105 | * No restriction for security.* and system.* from the VFS. Decision | |
106 | * on these is left to the underlying filesystem / security module. | |
107 | */ | |
108 | if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) || | |
109 | !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
110 | return 0; | |
111 | ||
112 | /* | |
55b23bde | 113 | * The trusted.* namespace can only be accessed by privileged users. |
e0ad7b07 | 114 | */ |
55b23bde AG |
115 | if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) { |
116 | if (!capable(CAP_SYS_ADMIN)) | |
117 | return (mask & MAY_WRITE) ? -EPERM : -ENODATA; | |
118 | return 0; | |
119 | } | |
e0ad7b07 | 120 | |
55b23bde AG |
121 | /* |
122 | * In the user.* namespace, only regular files and directories can have | |
f1f2d871 | 123 | * extended attributes. For sticky directories, only the owner and |
55b23bde | 124 | * privileged users can write attributes. |
f1f2d871 | 125 | */ |
e0ad7b07 | 126 | if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) { |
f1f2d871 | 127 | if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode)) |
55b23bde | 128 | return (mask & MAY_WRITE) ? -EPERM : -ENODATA; |
f1f2d871 | 129 | if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) && |
2e149670 | 130 | (mask & MAY_WRITE) && !inode_owner_or_capable(inode)) |
e0ad7b07 | 131 | return -EPERM; |
132 | } | |
133 | ||
f419a2e3 | 134 | return inode_permission(inode, mask); |
e0ad7b07 | 135 | } |
136 | ||
5d6c3191 AG |
137 | int |
138 | __vfs_setxattr(struct dentry *dentry, struct inode *inode, const char *name, | |
139 | const void *value, size_t size, int flags) | |
140 | { | |
6c6ef9f2 AG |
141 | const struct xattr_handler *handler; |
142 | ||
143 | handler = xattr_resolve_name(inode, &name); | |
144 | if (IS_ERR(handler)) | |
145 | return PTR_ERR(handler); | |
146 | if (!handler->set) | |
5d6c3191 | 147 | return -EOPNOTSUPP; |
6c6ef9f2 AG |
148 | if (size == 0) |
149 | value = ""; /* empty EA, do not remove */ | |
150 | return handler->set(handler, dentry, inode, name, value, size, flags); | |
5d6c3191 AG |
151 | } |
152 | EXPORT_SYMBOL(__vfs_setxattr); | |
153 | ||
b1ab7e4b DQ |
154 | /** |
155 | * __vfs_setxattr_noperm - perform setxattr operation without performing | |
156 | * permission checks. | |
157 | * | |
158 | * @dentry - object to perform setxattr on | |
159 | * @name - xattr name to set | |
160 | * @value - value to set @name to | |
161 | * @size - size of @value | |
162 | * @flags - flags to pass into filesystem operations | |
163 | * | |
164 | * returns the result of the internal setxattr or setsecurity operations. | |
165 | * | |
166 | * This function requires the caller to lock the inode's i_mutex before it | |
167 | * is executed. It also assumes that the caller will make the appropriate | |
168 | * permission checks. | |
169 | */ | |
170 | int __vfs_setxattr_noperm(struct dentry *dentry, const char *name, | |
171 | const void *value, size_t size, int flags) | |
5be196e5 CH |
172 | { |
173 | struct inode *inode = dentry->d_inode; | |
4a590153 | 174 | int error = -EAGAIN; |
69b45732 AK |
175 | int issec = !strncmp(name, XATTR_SECURITY_PREFIX, |
176 | XATTR_SECURITY_PREFIX_LEN); | |
e0ad7b07 | 177 | |
69b45732 AK |
178 | if (issec) |
179 | inode->i_flags &= ~S_NOSEC; | |
6c6ef9f2 | 180 | if (inode->i_opflags & IOP_XATTR) { |
5d6c3191 | 181 | error = __vfs_setxattr(dentry, inode, name, value, size, flags); |
5be196e5 CH |
182 | if (!error) { |
183 | fsnotify_xattr(dentry); | |
184 | security_inode_post_setxattr(dentry, name, value, | |
185 | size, flags); | |
186 | } | |
4a590153 | 187 | } else { |
5f6e59ae AG |
188 | if (unlikely(is_bad_inode(inode))) |
189 | return -EIO; | |
4a590153 AG |
190 | } |
191 | if (error == -EAGAIN) { | |
192 | error = -EOPNOTSUPP; | |
193 | ||
194 | if (issec) { | |
195 | const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; | |
196 | ||
197 | error = security_inode_setsecurity(inode, suffix, value, | |
198 | size, flags); | |
199 | if (!error) | |
200 | fsnotify_xattr(dentry); | |
201 | } | |
5be196e5 | 202 | } |
b1ab7e4b DQ |
203 | |
204 | return error; | |
205 | } | |
d3d00ed4 | 206 | EXPORT_SYMBOL_GPL(__vfs_setxattr_noperm); |
b1ab7e4b DQ |
207 | |
208 | ||
209 | int | |
210 | vfs_setxattr(struct dentry *dentry, const char *name, const void *value, | |
211 | size_t size, int flags) | |
212 | { | |
213 | struct inode *inode = dentry->d_inode; | |
214 | int error; | |
215 | ||
216 | error = xattr_permission(inode, name, MAY_WRITE); | |
217 | if (error) | |
218 | return error; | |
219 | ||
5955102c | 220 | inode_lock(inode); |
b1ab7e4b DQ |
221 | error = security_inode_setxattr(dentry, name, value, size, flags); |
222 | if (error) | |
223 | goto out; | |
224 | ||
225 | error = __vfs_setxattr_noperm(dentry, name, value, size, flags); | |
226 | ||
5be196e5 | 227 | out: |
5955102c | 228 | inode_unlock(inode); |
5be196e5 CH |
229 | return error; |
230 | } | |
231 | EXPORT_SYMBOL_GPL(vfs_setxattr); | |
232 | ||
42492594 DQ |
233 | ssize_t |
234 | xattr_getsecurity(struct inode *inode, const char *name, void *value, | |
235 | size_t size) | |
236 | { | |
237 | void *buffer = NULL; | |
238 | ssize_t len; | |
239 | ||
240 | if (!value || !size) { | |
241 | len = security_inode_getsecurity(inode, name, &buffer, false); | |
242 | goto out_noalloc; | |
243 | } | |
244 | ||
245 | len = security_inode_getsecurity(inode, name, &buffer, true); | |
246 | if (len < 0) | |
247 | return len; | |
248 | if (size < len) { | |
249 | len = -ERANGE; | |
250 | goto out; | |
251 | } | |
252 | memcpy(value, buffer, len); | |
253 | out: | |
57e7ba04 | 254 | kfree(buffer); |
42492594 DQ |
255 | out_noalloc: |
256 | return len; | |
257 | } | |
258 | EXPORT_SYMBOL_GPL(xattr_getsecurity); | |
259 | ||
1601fbad MZ |
260 | /* |
261 | * vfs_getxattr_alloc - allocate memory, if necessary, before calling getxattr | |
262 | * | |
263 | * Allocate memory, if not already allocated, or re-allocate correct size, | |
264 | * before retrieving the extended attribute. | |
265 | * | |
266 | * Returns the result of alloc, if failed, or the getxattr operation. | |
267 | */ | |
268 | ssize_t | |
269 | vfs_getxattr_alloc(struct dentry *dentry, const char *name, char **xattr_value, | |
270 | size_t xattr_size, gfp_t flags) | |
271 | { | |
6c6ef9f2 | 272 | const struct xattr_handler *handler; |
1601fbad MZ |
273 | struct inode *inode = dentry->d_inode; |
274 | char *value = *xattr_value; | |
275 | int error; | |
276 | ||
277 | error = xattr_permission(inode, name, MAY_READ); | |
278 | if (error) | |
279 | return error; | |
280 | ||
6c6ef9f2 AG |
281 | handler = xattr_resolve_name(inode, &name); |
282 | if (IS_ERR(handler)) | |
283 | return PTR_ERR(handler); | |
284 | if (!handler->get) | |
1601fbad | 285 | return -EOPNOTSUPP; |
6c6ef9f2 | 286 | error = handler->get(handler, dentry, inode, name, NULL, 0); |
1601fbad MZ |
287 | if (error < 0) |
288 | return error; | |
289 | ||
290 | if (!value || (error > xattr_size)) { | |
291 | value = krealloc(*xattr_value, error + 1, flags); | |
292 | if (!value) | |
293 | return -ENOMEM; | |
294 | memset(value, 0, error + 1); | |
295 | } | |
296 | ||
6c6ef9f2 | 297 | error = handler->get(handler, dentry, inode, name, value, error); |
1601fbad MZ |
298 | *xattr_value = value; |
299 | return error; | |
300 | } | |
c088e31d | 301 | EXPORT_SYMBOL_GPL(vfs_getxattr_alloc); |
1601fbad | 302 | |
5d6c3191 AG |
303 | ssize_t |
304 | __vfs_getxattr(struct dentry *dentry, struct inode *inode, const char *name, | |
305 | void *value, size_t size) | |
306 | { | |
6c6ef9f2 AG |
307 | const struct xattr_handler *handler; |
308 | ||
309 | handler = xattr_resolve_name(inode, &name); | |
310 | if (IS_ERR(handler)) | |
311 | return PTR_ERR(handler); | |
312 | if (!handler->get) | |
5d6c3191 | 313 | return -EOPNOTSUPP; |
6c6ef9f2 | 314 | return handler->get(handler, dentry, inode, name, value, size); |
5d6c3191 AG |
315 | } |
316 | EXPORT_SYMBOL(__vfs_getxattr); | |
317 | ||
5be196e5 | 318 | ssize_t |
8f0cfa52 | 319 | vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size) |
5be196e5 CH |
320 | { |
321 | struct inode *inode = dentry->d_inode; | |
322 | int error; | |
323 | ||
e0ad7b07 | 324 | error = xattr_permission(inode, name, MAY_READ); |
325 | if (error) | |
326 | return error; | |
327 | ||
5be196e5 CH |
328 | error = security_inode_getxattr(dentry, name); |
329 | if (error) | |
330 | return error; | |
331 | ||
5be196e5 | 332 | if (!strncmp(name, XATTR_SECURITY_PREFIX, |
e0ad7b07 | 333 | XATTR_SECURITY_PREFIX_LEN)) { |
334 | const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; | |
42492594 | 335 | int ret = xattr_getsecurity(inode, suffix, value, size); |
5be196e5 CH |
336 | /* |
337 | * Only overwrite the return value if a security module | |
338 | * is actually active. | |
339 | */ | |
4bea5805 DQ |
340 | if (ret == -EOPNOTSUPP) |
341 | goto nolsm; | |
342 | return ret; | |
5be196e5 | 343 | } |
4bea5805 | 344 | nolsm: |
5d6c3191 | 345 | return __vfs_getxattr(dentry, inode, name, value, size); |
5be196e5 CH |
346 | } |
347 | EXPORT_SYMBOL_GPL(vfs_getxattr); | |
348 | ||
659564c8 | 349 | ssize_t |
bf3ee713 | 350 | vfs_listxattr(struct dentry *dentry, char *list, size_t size) |
659564c8 | 351 | { |
bf3ee713 | 352 | struct inode *inode = d_inode(dentry); |
659564c8 BN |
353 | ssize_t error; |
354 | ||
bf3ee713 | 355 | error = security_inode_listxattr(dentry); |
659564c8 BN |
356 | if (error) |
357 | return error; | |
bf3ee713 AG |
358 | if (inode->i_op->listxattr && (inode->i_opflags & IOP_XATTR)) { |
359 | error = -EOPNOTSUPP; | |
360 | error = inode->i_op->listxattr(dentry, list, size); | |
659564c8 | 361 | } else { |
bf3ee713 | 362 | error = security_inode_listsecurity(inode, list, size); |
659564c8 BN |
363 | if (size && error > size) |
364 | error = -ERANGE; | |
365 | } | |
366 | return error; | |
367 | } | |
368 | EXPORT_SYMBOL_GPL(vfs_listxattr); | |
369 | ||
5be196e5 | 370 | int |
5d6c3191 | 371 | __vfs_removexattr(struct dentry *dentry, const char *name) |
5be196e5 | 372 | { |
6c6ef9f2 AG |
373 | struct inode *inode = d_inode(dentry); |
374 | const struct xattr_handler *handler; | |
5be196e5 | 375 | |
6c6ef9f2 AG |
376 | handler = xattr_resolve_name(inode, &name); |
377 | if (IS_ERR(handler)) | |
378 | return PTR_ERR(handler); | |
379 | if (!handler->set) | |
5be196e5 | 380 | return -EOPNOTSUPP; |
6c6ef9f2 | 381 | return handler->set(handler, dentry, inode, name, NULL, 0, XATTR_REPLACE); |
5d6c3191 AG |
382 | } |
383 | EXPORT_SYMBOL(__vfs_removexattr); | |
384 | ||
d3d00ed4 SF |
385 | /** |
386 | * __vfs_removexattr_noperm - perform removexattr operation without | |
387 | * performing permission checks. | |
388 | * | |
389 | * @dentry - object to perform setxattr on | |
390 | * @name - xattr name to set | |
391 | * | |
392 | * returns the result of the internal setxattr or setsecurity operations. | |
393 | * | |
394 | * This function requires the caller to lock the inode's i_mutex before it | |
395 | * is executed. It also assumes that the caller will make the appropriate | |
396 | * permission checks. | |
397 | */ | |
398 | int | |
399 | __vfs_removexattr_noperm(struct dentry *dentry, const char *name) | |
400 | { | |
401 | int error; | |
402 | ||
403 | error =__vfs_removexattr(dentry, name); | |
404 | if (!error) { | |
405 | fsnotify_xattr(dentry); | |
406 | evm_inode_post_removexattr(dentry, name); | |
407 | } | |
408 | return error; | |
409 | } | |
410 | EXPORT_SYMBOL_GPL(__vfs_removexattr_noperm); | |
411 | ||
5d6c3191 AG |
412 | int |
413 | vfs_removexattr(struct dentry *dentry, const char *name) | |
414 | { | |
415 | struct inode *inode = dentry->d_inode; | |
416 | int error; | |
5be196e5 | 417 | |
e0ad7b07 | 418 | error = xattr_permission(inode, name, MAY_WRITE); |
419 | if (error) | |
420 | return error; | |
421 | ||
5955102c | 422 | inode_lock(inode); |
5be196e5 | 423 | error = security_inode_removexattr(dentry, name); |
7c51bb00 DK |
424 | if (error) |
425 | goto out; | |
5be196e5 | 426 | |
d3d00ed4 | 427 | error = __vfs_removexattr_noperm(dentry, name); |
7c51bb00 DK |
428 | |
429 | out: | |
5955102c | 430 | inode_unlock(inode); |
5be196e5 CH |
431 | return error; |
432 | } | |
433 | EXPORT_SYMBOL_GPL(vfs_removexattr); | |
434 | ||
435 | ||
1da177e4 LT |
436 | /* |
437 | * Extended attribute SET operations | |
438 | */ | |
439 | static long | |
8f0cfa52 | 440 | setxattr(struct dentry *d, const char __user *name, const void __user *value, |
1da177e4 LT |
441 | size_t size, int flags) |
442 | { | |
443 | int error; | |
444 | void *kvalue = NULL; | |
445 | char kname[XATTR_NAME_MAX + 1]; | |
446 | ||
447 | if (flags & ~(XATTR_CREATE|XATTR_REPLACE)) | |
448 | return -EINVAL; | |
449 | ||
450 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
451 | if (error == 0 || error == sizeof(kname)) | |
452 | error = -ERANGE; | |
453 | if (error < 0) | |
454 | return error; | |
455 | ||
456 | if (size) { | |
457 | if (size > XATTR_SIZE_MAX) | |
458 | return -E2BIG; | |
752ade68 MH |
459 | kvalue = kvmalloc(size, GFP_KERNEL); |
460 | if (!kvalue) | |
461 | return -ENOMEM; | |
44c82498 AM |
462 | if (copy_from_user(kvalue, value, size)) { |
463 | error = -EFAULT; | |
464 | goto out; | |
465 | } | |
2f6f0654 EB |
466 | if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) || |
467 | (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)) | |
468 | posix_acl_fix_xattr_from_user(kvalue, size); | |
8db6c34f SH |
469 | else if (strcmp(kname, XATTR_NAME_CAPS) == 0) { |
470 | error = cap_convert_nscap(d, &kvalue, size); | |
471 | if (error < 0) | |
472 | goto out; | |
473 | size = error; | |
474 | } | |
1da177e4 LT |
475 | } |
476 | ||
5be196e5 | 477 | error = vfs_setxattr(d, kname, kvalue, size, flags); |
44c82498 | 478 | out: |
0b2a6f23 RW |
479 | kvfree(kvalue); |
480 | ||
1da177e4 LT |
481 | return error; |
482 | } | |
483 | ||
8cc43116 EB |
484 | static int path_setxattr(const char __user *pathname, |
485 | const char __user *name, const void __user *value, | |
486 | size_t size, int flags, unsigned int lookup_flags) | |
1da177e4 | 487 | { |
2d8f3038 | 488 | struct path path; |
1da177e4 | 489 | int error; |
68f1bb8b JL |
490 | retry: |
491 | error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); | |
1da177e4 LT |
492 | if (error) |
493 | return error; | |
2d8f3038 | 494 | error = mnt_want_write(path.mnt); |
18f335af | 495 | if (!error) { |
2d8f3038 AV |
496 | error = setxattr(path.dentry, name, value, size, flags); |
497 | mnt_drop_write(path.mnt); | |
18f335af | 498 | } |
2d8f3038 | 499 | path_put(&path); |
68f1bb8b JL |
500 | if (retry_estale(error, lookup_flags)) { |
501 | lookup_flags |= LOOKUP_REVAL; | |
502 | goto retry; | |
503 | } | |
1da177e4 LT |
504 | return error; |
505 | } | |
506 | ||
8cc43116 EB |
507 | SYSCALL_DEFINE5(setxattr, const char __user *, pathname, |
508 | const char __user *, name, const void __user *, value, | |
509 | size_t, size, int, flags) | |
510 | { | |
511 | return path_setxattr(pathname, name, value, size, flags, LOOKUP_FOLLOW); | |
512 | } | |
513 | ||
64fd1de3 HC |
514 | SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname, |
515 | const char __user *, name, const void __user *, value, | |
516 | size_t, size, int, flags) | |
1da177e4 | 517 | { |
8cc43116 | 518 | return path_setxattr(pathname, name, value, size, flags, 0); |
1da177e4 LT |
519 | } |
520 | ||
64fd1de3 HC |
521 | SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name, |
522 | const void __user *,value, size_t, size, int, flags) | |
1da177e4 | 523 | { |
2903ff01 | 524 | struct fd f = fdget(fd); |
1da177e4 LT |
525 | int error = -EBADF; |
526 | ||
2903ff01 | 527 | if (!f.file) |
1da177e4 | 528 | return error; |
9f45f5bf | 529 | audit_file(f.file); |
7c6893e3 | 530 | error = mnt_want_write_file_path(f.file); |
18f335af | 531 | if (!error) { |
9f45f5bf | 532 | error = setxattr(f.file->f_path.dentry, name, value, size, flags); |
7c6893e3 | 533 | mnt_drop_write_file_path(f.file); |
18f335af | 534 | } |
2903ff01 | 535 | fdput(f); |
1da177e4 LT |
536 | return error; |
537 | } | |
538 | ||
539 | /* | |
540 | * Extended attribute GET operations | |
541 | */ | |
542 | static ssize_t | |
8f0cfa52 DH |
543 | getxattr(struct dentry *d, const char __user *name, void __user *value, |
544 | size_t size) | |
1da177e4 LT |
545 | { |
546 | ssize_t error; | |
547 | void *kvalue = NULL; | |
548 | char kname[XATTR_NAME_MAX + 1]; | |
549 | ||
550 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
551 | if (error == 0 || error == sizeof(kname)) | |
552 | error = -ERANGE; | |
553 | if (error < 0) | |
554 | return error; | |
555 | ||
556 | if (size) { | |
557 | if (size > XATTR_SIZE_MAX) | |
558 | size = XATTR_SIZE_MAX; | |
752ade68 MH |
559 | kvalue = kvzalloc(size, GFP_KERNEL); |
560 | if (!kvalue) | |
561 | return -ENOMEM; | |
1da177e4 LT |
562 | } |
563 | ||
5be196e5 | 564 | error = vfs_getxattr(d, kname, kvalue, size); |
f549d6c1 | 565 | if (error > 0) { |
2f6f0654 EB |
566 | if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) || |
567 | (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)) | |
6404c6e9 | 568 | posix_acl_fix_xattr_to_user(kvalue, error); |
f549d6c1 SS |
569 | if (size && copy_to_user(value, kvalue, error)) |
570 | error = -EFAULT; | |
571 | } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) { | |
572 | /* The file system tried to returned a value bigger | |
573 | than XATTR_SIZE_MAX bytes. Not possible. */ | |
574 | error = -E2BIG; | |
1da177e4 | 575 | } |
0b2a6f23 RW |
576 | |
577 | kvfree(kvalue); | |
578 | ||
1da177e4 LT |
579 | return error; |
580 | } | |
581 | ||
8cc43116 EB |
582 | static ssize_t path_getxattr(const char __user *pathname, |
583 | const char __user *name, void __user *value, | |
584 | size_t size, unsigned int lookup_flags) | |
1da177e4 | 585 | { |
2d8f3038 | 586 | struct path path; |
1da177e4 | 587 | ssize_t error; |
60e66b48 JL |
588 | retry: |
589 | error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); | |
1da177e4 LT |
590 | if (error) |
591 | return error; | |
2d8f3038 AV |
592 | error = getxattr(path.dentry, name, value, size); |
593 | path_put(&path); | |
60e66b48 JL |
594 | if (retry_estale(error, lookup_flags)) { |
595 | lookup_flags |= LOOKUP_REVAL; | |
596 | goto retry; | |
597 | } | |
1da177e4 LT |
598 | return error; |
599 | } | |
600 | ||
8cc43116 EB |
601 | SYSCALL_DEFINE4(getxattr, const char __user *, pathname, |
602 | const char __user *, name, void __user *, value, size_t, size) | |
603 | { | |
604 | return path_getxattr(pathname, name, value, size, LOOKUP_FOLLOW); | |
605 | } | |
606 | ||
64fd1de3 HC |
607 | SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname, |
608 | const char __user *, name, void __user *, value, size_t, size) | |
1da177e4 | 609 | { |
8cc43116 | 610 | return path_getxattr(pathname, name, value, size, 0); |
1da177e4 LT |
611 | } |
612 | ||
64fd1de3 HC |
613 | SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name, |
614 | void __user *, value, size_t, size) | |
1da177e4 | 615 | { |
2903ff01 | 616 | struct fd f = fdget(fd); |
1da177e4 LT |
617 | ssize_t error = -EBADF; |
618 | ||
2903ff01 | 619 | if (!f.file) |
1da177e4 | 620 | return error; |
9f45f5bf | 621 | audit_file(f.file); |
2903ff01 AV |
622 | error = getxattr(f.file->f_path.dentry, name, value, size); |
623 | fdput(f); | |
1da177e4 LT |
624 | return error; |
625 | } | |
626 | ||
627 | /* | |
628 | * Extended attribute LIST operations | |
629 | */ | |
630 | static ssize_t | |
631 | listxattr(struct dentry *d, char __user *list, size_t size) | |
632 | { | |
633 | ssize_t error; | |
634 | char *klist = NULL; | |
635 | ||
636 | if (size) { | |
637 | if (size > XATTR_LIST_MAX) | |
638 | size = XATTR_LIST_MAX; | |
752ade68 MH |
639 | klist = kvmalloc(size, GFP_KERNEL); |
640 | if (!klist) | |
641 | return -ENOMEM; | |
1da177e4 LT |
642 | } |
643 | ||
659564c8 | 644 | error = vfs_listxattr(d, klist, size); |
f549d6c1 SS |
645 | if (error > 0) { |
646 | if (size && copy_to_user(list, klist, error)) | |
647 | error = -EFAULT; | |
648 | } else if (error == -ERANGE && size >= XATTR_LIST_MAX) { | |
649 | /* The file system tried to returned a list bigger | |
650 | than XATTR_LIST_MAX bytes. Not possible. */ | |
651 | error = -E2BIG; | |
1da177e4 | 652 | } |
0b2a6f23 RW |
653 | |
654 | kvfree(klist); | |
655 | ||
1da177e4 LT |
656 | return error; |
657 | } | |
658 | ||
8cc43116 EB |
659 | static ssize_t path_listxattr(const char __user *pathname, char __user *list, |
660 | size_t size, unsigned int lookup_flags) | |
1da177e4 | 661 | { |
2d8f3038 | 662 | struct path path; |
1da177e4 | 663 | ssize_t error; |
10a90cf3 JL |
664 | retry: |
665 | error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); | |
1da177e4 LT |
666 | if (error) |
667 | return error; | |
2d8f3038 AV |
668 | error = listxattr(path.dentry, list, size); |
669 | path_put(&path); | |
10a90cf3 JL |
670 | if (retry_estale(error, lookup_flags)) { |
671 | lookup_flags |= LOOKUP_REVAL; | |
672 | goto retry; | |
673 | } | |
1da177e4 LT |
674 | return error; |
675 | } | |
676 | ||
8cc43116 EB |
677 | SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list, |
678 | size_t, size) | |
679 | { | |
680 | return path_listxattr(pathname, list, size, LOOKUP_FOLLOW); | |
681 | } | |
682 | ||
64fd1de3 HC |
683 | SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list, |
684 | size_t, size) | |
1da177e4 | 685 | { |
8cc43116 | 686 | return path_listxattr(pathname, list, size, 0); |
1da177e4 LT |
687 | } |
688 | ||
64fd1de3 | 689 | SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size) |
1da177e4 | 690 | { |
2903ff01 | 691 | struct fd f = fdget(fd); |
1da177e4 LT |
692 | ssize_t error = -EBADF; |
693 | ||
2903ff01 | 694 | if (!f.file) |
1da177e4 | 695 | return error; |
9f45f5bf | 696 | audit_file(f.file); |
2903ff01 AV |
697 | error = listxattr(f.file->f_path.dentry, list, size); |
698 | fdput(f); | |
1da177e4 LT |
699 | return error; |
700 | } | |
701 | ||
702 | /* | |
703 | * Extended attribute REMOVE operations | |
704 | */ | |
705 | static long | |
8f0cfa52 | 706 | removexattr(struct dentry *d, const char __user *name) |
1da177e4 LT |
707 | { |
708 | int error; | |
709 | char kname[XATTR_NAME_MAX + 1]; | |
710 | ||
711 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
712 | if (error == 0 || error == sizeof(kname)) | |
713 | error = -ERANGE; | |
714 | if (error < 0) | |
715 | return error; | |
716 | ||
5be196e5 | 717 | return vfs_removexattr(d, kname); |
1da177e4 LT |
718 | } |
719 | ||
8cc43116 EB |
720 | static int path_removexattr(const char __user *pathname, |
721 | const char __user *name, unsigned int lookup_flags) | |
1da177e4 | 722 | { |
2d8f3038 | 723 | struct path path; |
1da177e4 | 724 | int error; |
12f06212 JL |
725 | retry: |
726 | error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); | |
1da177e4 LT |
727 | if (error) |
728 | return error; | |
2d8f3038 | 729 | error = mnt_want_write(path.mnt); |
18f335af | 730 | if (!error) { |
2d8f3038 AV |
731 | error = removexattr(path.dentry, name); |
732 | mnt_drop_write(path.mnt); | |
18f335af | 733 | } |
2d8f3038 | 734 | path_put(&path); |
12f06212 JL |
735 | if (retry_estale(error, lookup_flags)) { |
736 | lookup_flags |= LOOKUP_REVAL; | |
737 | goto retry; | |
738 | } | |
1da177e4 LT |
739 | return error; |
740 | } | |
741 | ||
8cc43116 EB |
742 | SYSCALL_DEFINE2(removexattr, const char __user *, pathname, |
743 | const char __user *, name) | |
744 | { | |
745 | return path_removexattr(pathname, name, LOOKUP_FOLLOW); | |
746 | } | |
747 | ||
6a6160a7 HC |
748 | SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname, |
749 | const char __user *, name) | |
1da177e4 | 750 | { |
8cc43116 | 751 | return path_removexattr(pathname, name, 0); |
1da177e4 LT |
752 | } |
753 | ||
6a6160a7 | 754 | SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name) |
1da177e4 | 755 | { |
2903ff01 | 756 | struct fd f = fdget(fd); |
1da177e4 LT |
757 | int error = -EBADF; |
758 | ||
2903ff01 | 759 | if (!f.file) |
1da177e4 | 760 | return error; |
9f45f5bf | 761 | audit_file(f.file); |
7c6893e3 | 762 | error = mnt_want_write_file_path(f.file); |
18f335af | 763 | if (!error) { |
9f45f5bf | 764 | error = removexattr(f.file->f_path.dentry, name); |
7c6893e3 | 765 | mnt_drop_write_file_path(f.file); |
18f335af | 766 | } |
2903ff01 | 767 | fdput(f); |
1da177e4 LT |
768 | return error; |
769 | } | |
770 | ||
1da177e4 LT |
771 | /* |
772 | * Combine the results of the list() operation from every xattr_handler in the | |
773 | * list. | |
774 | */ | |
775 | ssize_t | |
776 | generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) | |
777 | { | |
bb435453 | 778 | const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr; |
1da177e4 LT |
779 | unsigned int size = 0; |
780 | ||
781 | if (!buffer) { | |
431547b3 | 782 | for_each_xattr_handler(handlers, handler) { |
764a5c6b AG |
783 | if (!handler->name || |
784 | (handler->list && !handler->list(dentry))) | |
c4803c49 | 785 | continue; |
764a5c6b | 786 | size += strlen(handler->name) + 1; |
431547b3 | 787 | } |
1da177e4 LT |
788 | } else { |
789 | char *buf = buffer; | |
764a5c6b | 790 | size_t len; |
1da177e4 LT |
791 | |
792 | for_each_xattr_handler(handlers, handler) { | |
764a5c6b AG |
793 | if (!handler->name || |
794 | (handler->list && !handler->list(dentry))) | |
c4803c49 | 795 | continue; |
764a5c6b AG |
796 | len = strlen(handler->name); |
797 | if (len + 1 > buffer_size) | |
1da177e4 | 798 | return -ERANGE; |
764a5c6b AG |
799 | memcpy(buf, handler->name, len + 1); |
800 | buf += len + 1; | |
801 | buffer_size -= len + 1; | |
1da177e4 LT |
802 | } |
803 | size = buf - buffer; | |
804 | } | |
805 | return size; | |
806 | } | |
1da177e4 | 807 | EXPORT_SYMBOL(generic_listxattr); |
38f38657 | 808 | |
e409de99 AG |
809 | /** |
810 | * xattr_full_name - Compute full attribute name from suffix | |
811 | * | |
812 | * @handler: handler of the xattr_handler operation | |
813 | * @name: name passed to the xattr_handler operation | |
814 | * | |
815 | * The get and set xattr handler operations are called with the remainder of | |
816 | * the attribute name after skipping the handler's prefix: for example, "foo" | |
817 | * is passed to the get operation of a handler with prefix "user." to get | |
818 | * attribute "user.foo". The full name is still "there" in the name though. | |
819 | * | |
820 | * Note: the list xattr handler operation when called from the vfs is passed a | |
821 | * NULL name; some file systems use this operation internally, with varying | |
822 | * semantics. | |
823 | */ | |
824 | const char *xattr_full_name(const struct xattr_handler *handler, | |
825 | const char *name) | |
826 | { | |
98e9cb57 | 827 | size_t prefix_len = strlen(xattr_prefix(handler)); |
e409de99 AG |
828 | |
829 | return name - prefix_len; | |
830 | } | |
831 | EXPORT_SYMBOL(xattr_full_name); | |
832 | ||
38f38657 AR |
833 | /* |
834 | * Allocate new xattr and copy in the value; but leave the name to callers. | |
835 | */ | |
836 | struct simple_xattr *simple_xattr_alloc(const void *value, size_t size) | |
837 | { | |
838 | struct simple_xattr *new_xattr; | |
839 | size_t len; | |
840 | ||
841 | /* wrap around? */ | |
842 | len = sizeof(*new_xattr) + size; | |
4e66d445 | 843 | if (len < sizeof(*new_xattr)) |
38f38657 AR |
844 | return NULL; |
845 | ||
846 | new_xattr = kmalloc(len, GFP_KERNEL); | |
847 | if (!new_xattr) | |
848 | return NULL; | |
849 | ||
850 | new_xattr->size = size; | |
851 | memcpy(new_xattr->value, value, size); | |
852 | return new_xattr; | |
853 | } | |
854 | ||
855 | /* | |
856 | * xattr GET operation for in-memory/pseudo filesystems | |
857 | */ | |
858 | int simple_xattr_get(struct simple_xattrs *xattrs, const char *name, | |
859 | void *buffer, size_t size) | |
860 | { | |
861 | struct simple_xattr *xattr; | |
862 | int ret = -ENODATA; | |
863 | ||
864 | spin_lock(&xattrs->lock); | |
865 | list_for_each_entry(xattr, &xattrs->head, list) { | |
866 | if (strcmp(name, xattr->name)) | |
867 | continue; | |
868 | ||
869 | ret = xattr->size; | |
870 | if (buffer) { | |
871 | if (size < xattr->size) | |
872 | ret = -ERANGE; | |
873 | else | |
874 | memcpy(buffer, xattr->value, xattr->size); | |
875 | } | |
876 | break; | |
877 | } | |
878 | spin_unlock(&xattrs->lock); | |
879 | return ret; | |
880 | } | |
881 | ||
aa7c5241 AG |
882 | /** |
883 | * simple_xattr_set - xattr SET operation for in-memory/pseudo filesystems | |
884 | * @xattrs: target simple_xattr list | |
885 | * @name: name of the extended attribute | |
886 | * @value: value of the xattr. If %NULL, will remove the attribute. | |
887 | * @size: size of the new xattr | |
888 | * @flags: %XATTR_{CREATE|REPLACE} | |
889 | * | |
890 | * %XATTR_CREATE is set, the xattr shouldn't exist already; otherwise fails | |
891 | * with -EEXIST. If %XATTR_REPLACE is set, the xattr should exist; | |
892 | * otherwise, fails with -ENODATA. | |
893 | * | |
894 | * Returns 0 on success, -errno on failure. | |
895 | */ | |
896 | int simple_xattr_set(struct simple_xattrs *xattrs, const char *name, | |
897 | const void *value, size_t size, int flags) | |
38f38657 AR |
898 | { |
899 | struct simple_xattr *xattr; | |
43385846 | 900 | struct simple_xattr *new_xattr = NULL; |
38f38657 AR |
901 | int err = 0; |
902 | ||
903 | /* value == NULL means remove */ | |
904 | if (value) { | |
905 | new_xattr = simple_xattr_alloc(value, size); | |
906 | if (!new_xattr) | |
907 | return -ENOMEM; | |
908 | ||
909 | new_xattr->name = kstrdup(name, GFP_KERNEL); | |
910 | if (!new_xattr->name) { | |
911 | kfree(new_xattr); | |
912 | return -ENOMEM; | |
913 | } | |
914 | } | |
915 | ||
916 | spin_lock(&xattrs->lock); | |
917 | list_for_each_entry(xattr, &xattrs->head, list) { | |
918 | if (!strcmp(name, xattr->name)) { | |
919 | if (flags & XATTR_CREATE) { | |
920 | xattr = new_xattr; | |
921 | err = -EEXIST; | |
922 | } else if (new_xattr) { | |
923 | list_replace(&xattr->list, &new_xattr->list); | |
924 | } else { | |
925 | list_del(&xattr->list); | |
926 | } | |
927 | goto out; | |
928 | } | |
929 | } | |
930 | if (flags & XATTR_REPLACE) { | |
931 | xattr = new_xattr; | |
932 | err = -ENODATA; | |
933 | } else { | |
934 | list_add(&new_xattr->list, &xattrs->head); | |
935 | xattr = NULL; | |
936 | } | |
937 | out: | |
938 | spin_unlock(&xattrs->lock); | |
939 | if (xattr) { | |
940 | kfree(xattr->name); | |
941 | kfree(xattr); | |
942 | } | |
943 | return err; | |
944 | ||
945 | } | |
946 | ||
38f38657 AR |
947 | static bool xattr_is_trusted(const char *name) |
948 | { | |
949 | return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN); | |
950 | } | |
951 | ||
786534b9 AG |
952 | static int xattr_list_one(char **buffer, ssize_t *remaining_size, |
953 | const char *name) | |
954 | { | |
955 | size_t len = strlen(name) + 1; | |
956 | if (*buffer) { | |
957 | if (*remaining_size < len) | |
958 | return -ERANGE; | |
959 | memcpy(*buffer, name, len); | |
960 | *buffer += len; | |
961 | } | |
962 | *remaining_size -= len; | |
963 | return 0; | |
964 | } | |
965 | ||
38f38657 AR |
966 | /* |
967 | * xattr LIST operation for in-memory/pseudo filesystems | |
968 | */ | |
786534b9 AG |
969 | ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs, |
970 | char *buffer, size_t size) | |
38f38657 AR |
971 | { |
972 | bool trusted = capable(CAP_SYS_ADMIN); | |
973 | struct simple_xattr *xattr; | |
786534b9 | 974 | ssize_t remaining_size = size; |
0e9a7da5 | 975 | int err = 0; |
786534b9 AG |
976 | |
977 | #ifdef CONFIG_FS_POSIX_ACL | |
cb1099ff AG |
978 | if (IS_POSIXACL(inode)) { |
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 | } | |
786534b9 AG |
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 | } |