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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 | |
0d08d7b7 | 25 | #include <asm/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 | |
39 | * prefix with the generic xattr API, a filesystem should create a | |
40 | * null-terminated array of struct xattr_handler (one for each prefix) and | |
41 | * hang a pointer to it off of the s_xattr field of the superblock. | |
42 | * | |
43 | * The generic_fooxattr() functions will use this list to dispatch xattr | |
44 | * operations to the correct xattr_handler. | |
45 | */ | |
46 | #define for_each_xattr_handler(handlers, handler) \ | |
47 | if (handlers) \ | |
48 | for ((handler) = *(handlers)++; \ | |
49 | (handler) != NULL; \ | |
50 | (handler) = *(handlers)++) | |
51 | ||
52 | /* | |
53 | * Find the xattr_handler with the matching prefix. | |
54 | */ | |
55 | static const struct xattr_handler * | |
d0a5b995 | 56 | xattr_resolve_name(struct inode *inode, const char **name) |
b6ba1177 | 57 | { |
d0a5b995 | 58 | const struct xattr_handler **handlers = inode->i_sb->s_xattr; |
b6ba1177 AG |
59 | const struct xattr_handler *handler; |
60 | ||
5f6e59ae AG |
61 | if (!(inode->i_opflags & IOP_XATTR)) { |
62 | if (unlikely(is_bad_inode(inode))) | |
63 | return ERR_PTR(-EIO); | |
d0a5b995 | 64 | return ERR_PTR(-EOPNOTSUPP); |
5f6e59ae | 65 | } |
b6ba1177 AG |
66 | for_each_xattr_handler(handlers, handler) { |
67 | const char *n; | |
68 | ||
69 | n = strcmp_prefix(*name, xattr_prefix(handler)); | |
70 | if (n) { | |
71 | if (!handler->prefix ^ !*n) { | |
72 | if (*n) | |
73 | continue; | |
74 | return ERR_PTR(-EINVAL); | |
75 | } | |
76 | *name = n; | |
77 | return handler; | |
78 | } | |
79 | } | |
80 | return ERR_PTR(-EOPNOTSUPP); | |
81 | } | |
82 | ||
e0ad7b07 | 83 | /* |
84 | * Check permissions for extended attribute access. This is a bit complicated | |
85 | * because different namespaces have very different rules. | |
86 | */ | |
87 | static int | |
88 | xattr_permission(struct inode *inode, const char *name, int mask) | |
89 | { | |
90 | /* | |
91 | * We can never set or remove an extended attribute on a read-only | |
92 | * filesystem or on an immutable / append-only inode. | |
93 | */ | |
94 | if (mask & MAY_WRITE) { | |
e0ad7b07 | 95 | if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) |
96 | return -EPERM; | |
0bd23d09 EB |
97 | /* |
98 | * Updating an xattr will likely cause i_uid and i_gid | |
99 | * to be writen back improperly if their true value is | |
100 | * unknown to the vfs. | |
101 | */ | |
102 | if (HAS_UNMAPPED_ID(inode)) | |
103 | return -EPERM; | |
e0ad7b07 | 104 | } |
105 | ||
106 | /* | |
107 | * No restriction for security.* and system.* from the VFS. Decision | |
108 | * on these is left to the underlying filesystem / security module. | |
109 | */ | |
110 | if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) || | |
111 | !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) | |
112 | return 0; | |
113 | ||
114 | /* | |
55b23bde | 115 | * The trusted.* namespace can only be accessed by privileged users. |
e0ad7b07 | 116 | */ |
55b23bde AG |
117 | if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) { |
118 | if (!capable(CAP_SYS_ADMIN)) | |
119 | return (mask & MAY_WRITE) ? -EPERM : -ENODATA; | |
120 | return 0; | |
121 | } | |
e0ad7b07 | 122 | |
55b23bde AG |
123 | /* |
124 | * In the user.* namespace, only regular files and directories can have | |
f1f2d871 | 125 | * extended attributes. For sticky directories, only the owner and |
55b23bde | 126 | * privileged users can write attributes. |
f1f2d871 | 127 | */ |
e0ad7b07 | 128 | if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) { |
f1f2d871 | 129 | if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode)) |
55b23bde | 130 | return (mask & MAY_WRITE) ? -EPERM : -ENODATA; |
f1f2d871 | 131 | if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) && |
2e149670 | 132 | (mask & MAY_WRITE) && !inode_owner_or_capable(inode)) |
e0ad7b07 | 133 | return -EPERM; |
134 | } | |
135 | ||
f419a2e3 | 136 | return inode_permission(inode, mask); |
e0ad7b07 | 137 | } |
138 | ||
5d6c3191 AG |
139 | int |
140 | __vfs_setxattr(struct dentry *dentry, struct inode *inode, const char *name, | |
141 | const void *value, size_t size, int flags) | |
142 | { | |
143 | if (!inode->i_op->setxattr) | |
144 | return -EOPNOTSUPP; | |
145 | return inode->i_op->setxattr(dentry, inode, name, value, size, flags); | |
146 | } | |
147 | EXPORT_SYMBOL(__vfs_setxattr); | |
148 | ||
b1ab7e4b DQ |
149 | /** |
150 | * __vfs_setxattr_noperm - perform setxattr operation without performing | |
151 | * permission checks. | |
152 | * | |
153 | * @dentry - object to perform setxattr on | |
154 | * @name - xattr name to set | |
155 | * @value - value to set @name to | |
156 | * @size - size of @value | |
157 | * @flags - flags to pass into filesystem operations | |
158 | * | |
159 | * returns the result of the internal setxattr or setsecurity operations. | |
160 | * | |
161 | * This function requires the caller to lock the inode's i_mutex before it | |
162 | * is executed. It also assumes that the caller will make the appropriate | |
163 | * permission checks. | |
164 | */ | |
165 | int __vfs_setxattr_noperm(struct dentry *dentry, const char *name, | |
166 | const void *value, size_t size, int flags) | |
5be196e5 CH |
167 | { |
168 | struct inode *inode = dentry->d_inode; | |
b1ab7e4b | 169 | int error = -EOPNOTSUPP; |
69b45732 AK |
170 | int issec = !strncmp(name, XATTR_SECURITY_PREFIX, |
171 | XATTR_SECURITY_PREFIX_LEN); | |
e0ad7b07 | 172 | |
69b45732 AK |
173 | if (issec) |
174 | inode->i_flags &= ~S_NOSEC; | |
5be196e5 | 175 | if (inode->i_op->setxattr) { |
5d6c3191 | 176 | error = __vfs_setxattr(dentry, inode, name, value, size, flags); |
5be196e5 CH |
177 | if (!error) { |
178 | fsnotify_xattr(dentry); | |
179 | security_inode_post_setxattr(dentry, name, value, | |
180 | size, flags); | |
181 | } | |
69b45732 | 182 | } else if (issec) { |
e0ad7b07 | 183 | const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; |
5f6e59ae AG |
184 | |
185 | if (unlikely(is_bad_inode(inode))) | |
186 | return -EIO; | |
5be196e5 CH |
187 | error = security_inode_setsecurity(inode, suffix, value, |
188 | size, flags); | |
189 | if (!error) | |
190 | fsnotify_xattr(dentry); | |
191 | } | |
b1ab7e4b DQ |
192 | |
193 | return error; | |
194 | } | |
195 | ||
196 | ||
197 | int | |
198 | vfs_setxattr(struct dentry *dentry, const char *name, const void *value, | |
199 | size_t size, int flags) | |
200 | { | |
201 | struct inode *inode = dentry->d_inode; | |
202 | int error; | |
203 | ||
204 | error = xattr_permission(inode, name, MAY_WRITE); | |
205 | if (error) | |
206 | return error; | |
207 | ||
5955102c | 208 | inode_lock(inode); |
b1ab7e4b DQ |
209 | error = security_inode_setxattr(dentry, name, value, size, flags); |
210 | if (error) | |
211 | goto out; | |
212 | ||
213 | error = __vfs_setxattr_noperm(dentry, name, value, size, flags); | |
214 | ||
5be196e5 | 215 | out: |
5955102c | 216 | inode_unlock(inode); |
5be196e5 CH |
217 | return error; |
218 | } | |
219 | EXPORT_SYMBOL_GPL(vfs_setxattr); | |
220 | ||
42492594 DQ |
221 | ssize_t |
222 | xattr_getsecurity(struct inode *inode, const char *name, void *value, | |
223 | size_t size) | |
224 | { | |
225 | void *buffer = NULL; | |
226 | ssize_t len; | |
227 | ||
228 | if (!value || !size) { | |
229 | len = security_inode_getsecurity(inode, name, &buffer, false); | |
230 | goto out_noalloc; | |
231 | } | |
232 | ||
233 | len = security_inode_getsecurity(inode, name, &buffer, true); | |
234 | if (len < 0) | |
235 | return len; | |
236 | if (size < len) { | |
237 | len = -ERANGE; | |
238 | goto out; | |
239 | } | |
240 | memcpy(value, buffer, len); | |
241 | out: | |
242 | security_release_secctx(buffer, len); | |
243 | out_noalloc: | |
244 | return len; | |
245 | } | |
246 | EXPORT_SYMBOL_GPL(xattr_getsecurity); | |
247 | ||
1601fbad MZ |
248 | /* |
249 | * vfs_getxattr_alloc - allocate memory, if necessary, before calling getxattr | |
250 | * | |
251 | * Allocate memory, if not already allocated, or re-allocate correct size, | |
252 | * before retrieving the extended attribute. | |
253 | * | |
254 | * Returns the result of alloc, if failed, or the getxattr operation. | |
255 | */ | |
256 | ssize_t | |
257 | vfs_getxattr_alloc(struct dentry *dentry, const char *name, char **xattr_value, | |
258 | size_t xattr_size, gfp_t flags) | |
259 | { | |
260 | struct inode *inode = dentry->d_inode; | |
261 | char *value = *xattr_value; | |
262 | int error; | |
263 | ||
264 | error = xattr_permission(inode, name, MAY_READ); | |
265 | if (error) | |
266 | return error; | |
267 | ||
268 | if (!inode->i_op->getxattr) | |
269 | return -EOPNOTSUPP; | |
270 | ||
ce23e640 | 271 | error = inode->i_op->getxattr(dentry, inode, name, NULL, 0); |
1601fbad MZ |
272 | if (error < 0) |
273 | return error; | |
274 | ||
275 | if (!value || (error > xattr_size)) { | |
276 | value = krealloc(*xattr_value, error + 1, flags); | |
277 | if (!value) | |
278 | return -ENOMEM; | |
279 | memset(value, 0, error + 1); | |
280 | } | |
281 | ||
ce23e640 | 282 | error = inode->i_op->getxattr(dentry, inode, name, value, error); |
1601fbad MZ |
283 | *xattr_value = value; |
284 | return error; | |
285 | } | |
286 | ||
5d6c3191 AG |
287 | ssize_t |
288 | __vfs_getxattr(struct dentry *dentry, struct inode *inode, const char *name, | |
289 | void *value, size_t size) | |
290 | { | |
291 | if (!inode->i_op->getxattr) | |
292 | return -EOPNOTSUPP; | |
293 | return inode->i_op->getxattr(dentry, inode, name, value, size); | |
294 | } | |
295 | EXPORT_SYMBOL(__vfs_getxattr); | |
296 | ||
5be196e5 | 297 | ssize_t |
8f0cfa52 | 298 | vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size) |
5be196e5 CH |
299 | { |
300 | struct inode *inode = dentry->d_inode; | |
301 | int error; | |
302 | ||
e0ad7b07 | 303 | error = xattr_permission(inode, name, MAY_READ); |
304 | if (error) | |
305 | return error; | |
306 | ||
5be196e5 CH |
307 | error = security_inode_getxattr(dentry, name); |
308 | if (error) | |
309 | return error; | |
310 | ||
5be196e5 | 311 | if (!strncmp(name, XATTR_SECURITY_PREFIX, |
e0ad7b07 | 312 | XATTR_SECURITY_PREFIX_LEN)) { |
313 | const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; | |
42492594 | 314 | int ret = xattr_getsecurity(inode, suffix, value, size); |
5be196e5 CH |
315 | /* |
316 | * Only overwrite the return value if a security module | |
317 | * is actually active. | |
318 | */ | |
4bea5805 DQ |
319 | if (ret == -EOPNOTSUPP) |
320 | goto nolsm; | |
321 | return ret; | |
5be196e5 | 322 | } |
4bea5805 | 323 | nolsm: |
5d6c3191 | 324 | return __vfs_getxattr(dentry, inode, name, value, size); |
5be196e5 CH |
325 | } |
326 | EXPORT_SYMBOL_GPL(vfs_getxattr); | |
327 | ||
659564c8 | 328 | ssize_t |
bf3ee713 | 329 | vfs_listxattr(struct dentry *dentry, char *list, size_t size) |
659564c8 | 330 | { |
bf3ee713 | 331 | struct inode *inode = d_inode(dentry); |
659564c8 BN |
332 | ssize_t error; |
333 | ||
bf3ee713 | 334 | error = security_inode_listxattr(dentry); |
659564c8 BN |
335 | if (error) |
336 | return error; | |
bf3ee713 AG |
337 | if (inode->i_op->listxattr && (inode->i_opflags & IOP_XATTR)) { |
338 | error = -EOPNOTSUPP; | |
339 | error = inode->i_op->listxattr(dentry, list, size); | |
659564c8 | 340 | } else { |
bf3ee713 | 341 | error = security_inode_listsecurity(inode, list, size); |
659564c8 BN |
342 | if (size && error > size) |
343 | error = -ERANGE; | |
344 | } | |
345 | return error; | |
346 | } | |
347 | EXPORT_SYMBOL_GPL(vfs_listxattr); | |
348 | ||
5be196e5 | 349 | int |
5d6c3191 | 350 | __vfs_removexattr(struct dentry *dentry, const char *name) |
5be196e5 CH |
351 | { |
352 | struct inode *inode = dentry->d_inode; | |
5be196e5 CH |
353 | |
354 | if (!inode->i_op->removexattr) | |
355 | return -EOPNOTSUPP; | |
5d6c3191 AG |
356 | return inode->i_op->removexattr(dentry, name); |
357 | } | |
358 | EXPORT_SYMBOL(__vfs_removexattr); | |
359 | ||
360 | int | |
361 | vfs_removexattr(struct dentry *dentry, const char *name) | |
362 | { | |
363 | struct inode *inode = dentry->d_inode; | |
364 | int error; | |
5be196e5 | 365 | |
e0ad7b07 | 366 | error = xattr_permission(inode, name, MAY_WRITE); |
367 | if (error) | |
368 | return error; | |
369 | ||
5955102c | 370 | inode_lock(inode); |
5be196e5 | 371 | error = security_inode_removexattr(dentry, name); |
7c51bb00 DK |
372 | if (error) |
373 | goto out; | |
5be196e5 | 374 | |
5d6c3191 | 375 | error = __vfs_removexattr(dentry, name); |
5be196e5 | 376 | |
c7b87de2 | 377 | if (!error) { |
5be196e5 | 378 | fsnotify_xattr(dentry); |
c7b87de2 MZ |
379 | evm_inode_post_removexattr(dentry, name); |
380 | } | |
7c51bb00 DK |
381 | |
382 | out: | |
5955102c | 383 | inode_unlock(inode); |
5be196e5 CH |
384 | return error; |
385 | } | |
386 | EXPORT_SYMBOL_GPL(vfs_removexattr); | |
387 | ||
388 | ||
1da177e4 LT |
389 | /* |
390 | * Extended attribute SET operations | |
391 | */ | |
392 | static long | |
8f0cfa52 | 393 | setxattr(struct dentry *d, const char __user *name, const void __user *value, |
1da177e4 LT |
394 | size_t size, int flags) |
395 | { | |
396 | int error; | |
397 | void *kvalue = NULL; | |
398 | char kname[XATTR_NAME_MAX + 1]; | |
399 | ||
400 | if (flags & ~(XATTR_CREATE|XATTR_REPLACE)) | |
401 | return -EINVAL; | |
402 | ||
403 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
404 | if (error == 0 || error == sizeof(kname)) | |
405 | error = -ERANGE; | |
406 | if (error < 0) | |
407 | return error; | |
408 | ||
409 | if (size) { | |
410 | if (size > XATTR_SIZE_MAX) | |
411 | return -E2BIG; | |
44c82498 AM |
412 | kvalue = kmalloc(size, GFP_KERNEL | __GFP_NOWARN); |
413 | if (!kvalue) { | |
0b2a6f23 RW |
414 | kvalue = vmalloc(size); |
415 | if (!kvalue) | |
44c82498 | 416 | return -ENOMEM; |
44c82498 AM |
417 | } |
418 | if (copy_from_user(kvalue, value, size)) { | |
419 | error = -EFAULT; | |
420 | goto out; | |
421 | } | |
2f6f0654 EB |
422 | if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) || |
423 | (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)) | |
424 | posix_acl_fix_xattr_from_user(kvalue, size); | |
1da177e4 LT |
425 | } |
426 | ||
5be196e5 | 427 | error = vfs_setxattr(d, kname, kvalue, size, flags); |
44c82498 | 428 | out: |
0b2a6f23 RW |
429 | kvfree(kvalue); |
430 | ||
1da177e4 LT |
431 | return error; |
432 | } | |
433 | ||
8cc43116 EB |
434 | static int path_setxattr(const char __user *pathname, |
435 | const char __user *name, const void __user *value, | |
436 | size_t size, int flags, unsigned int lookup_flags) | |
1da177e4 | 437 | { |
2d8f3038 | 438 | struct path path; |
1da177e4 | 439 | int error; |
68f1bb8b JL |
440 | retry: |
441 | error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); | |
1da177e4 LT |
442 | if (error) |
443 | return error; | |
2d8f3038 | 444 | error = mnt_want_write(path.mnt); |
18f335af | 445 | if (!error) { |
2d8f3038 AV |
446 | error = setxattr(path.dentry, name, value, size, flags); |
447 | mnt_drop_write(path.mnt); | |
18f335af | 448 | } |
2d8f3038 | 449 | path_put(&path); |
68f1bb8b JL |
450 | if (retry_estale(error, lookup_flags)) { |
451 | lookup_flags |= LOOKUP_REVAL; | |
452 | goto retry; | |
453 | } | |
1da177e4 LT |
454 | return error; |
455 | } | |
456 | ||
8cc43116 EB |
457 | SYSCALL_DEFINE5(setxattr, const char __user *, pathname, |
458 | const char __user *, name, const void __user *, value, | |
459 | size_t, size, int, flags) | |
460 | { | |
461 | return path_setxattr(pathname, name, value, size, flags, LOOKUP_FOLLOW); | |
462 | } | |
463 | ||
64fd1de3 HC |
464 | SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname, |
465 | const char __user *, name, const void __user *, value, | |
466 | size_t, size, int, flags) | |
1da177e4 | 467 | { |
8cc43116 | 468 | return path_setxattr(pathname, name, value, size, flags, 0); |
1da177e4 LT |
469 | } |
470 | ||
64fd1de3 HC |
471 | SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name, |
472 | const void __user *,value, size_t, size, int, flags) | |
1da177e4 | 473 | { |
2903ff01 | 474 | struct fd f = fdget(fd); |
1da177e4 LT |
475 | int error = -EBADF; |
476 | ||
2903ff01 | 477 | if (!f.file) |
1da177e4 | 478 | return error; |
9f45f5bf | 479 | audit_file(f.file); |
2903ff01 | 480 | error = mnt_want_write_file(f.file); |
18f335af | 481 | if (!error) { |
9f45f5bf | 482 | error = setxattr(f.file->f_path.dentry, name, value, size, flags); |
2903ff01 | 483 | mnt_drop_write_file(f.file); |
18f335af | 484 | } |
2903ff01 | 485 | fdput(f); |
1da177e4 LT |
486 | return error; |
487 | } | |
488 | ||
489 | /* | |
490 | * Extended attribute GET operations | |
491 | */ | |
492 | static ssize_t | |
8f0cfa52 DH |
493 | getxattr(struct dentry *d, const char __user *name, void __user *value, |
494 | size_t size) | |
1da177e4 LT |
495 | { |
496 | ssize_t error; | |
497 | void *kvalue = NULL; | |
498 | char kname[XATTR_NAME_MAX + 1]; | |
499 | ||
500 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
501 | if (error == 0 || error == sizeof(kname)) | |
502 | error = -ERANGE; | |
503 | if (error < 0) | |
504 | return error; | |
505 | ||
506 | if (size) { | |
507 | if (size > XATTR_SIZE_MAX) | |
508 | size = XATTR_SIZE_MAX; | |
779302e6 SL |
509 | kvalue = kzalloc(size, GFP_KERNEL | __GFP_NOWARN); |
510 | if (!kvalue) { | |
0b2a6f23 RW |
511 | kvalue = vmalloc(size); |
512 | if (!kvalue) | |
779302e6 | 513 | return -ENOMEM; |
779302e6 | 514 | } |
1da177e4 LT |
515 | } |
516 | ||
5be196e5 | 517 | error = vfs_getxattr(d, kname, kvalue, size); |
f549d6c1 | 518 | if (error > 0) { |
2f6f0654 EB |
519 | if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) || |
520 | (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)) | |
521 | posix_acl_fix_xattr_to_user(kvalue, size); | |
f549d6c1 SS |
522 | if (size && copy_to_user(value, kvalue, error)) |
523 | error = -EFAULT; | |
524 | } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) { | |
525 | /* The file system tried to returned a value bigger | |
526 | than XATTR_SIZE_MAX bytes. Not possible. */ | |
527 | error = -E2BIG; | |
1da177e4 | 528 | } |
0b2a6f23 RW |
529 | |
530 | kvfree(kvalue); | |
531 | ||
1da177e4 LT |
532 | return error; |
533 | } | |
534 | ||
8cc43116 EB |
535 | static ssize_t path_getxattr(const char __user *pathname, |
536 | const char __user *name, void __user *value, | |
537 | size_t size, unsigned int lookup_flags) | |
1da177e4 | 538 | { |
2d8f3038 | 539 | struct path path; |
1da177e4 | 540 | ssize_t error; |
60e66b48 JL |
541 | retry: |
542 | error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); | |
1da177e4 LT |
543 | if (error) |
544 | return error; | |
2d8f3038 AV |
545 | error = getxattr(path.dentry, name, value, size); |
546 | path_put(&path); | |
60e66b48 JL |
547 | if (retry_estale(error, lookup_flags)) { |
548 | lookup_flags |= LOOKUP_REVAL; | |
549 | goto retry; | |
550 | } | |
1da177e4 LT |
551 | return error; |
552 | } | |
553 | ||
8cc43116 EB |
554 | SYSCALL_DEFINE4(getxattr, const char __user *, pathname, |
555 | const char __user *, name, void __user *, value, size_t, size) | |
556 | { | |
557 | return path_getxattr(pathname, name, value, size, LOOKUP_FOLLOW); | |
558 | } | |
559 | ||
64fd1de3 HC |
560 | SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname, |
561 | const char __user *, name, void __user *, value, size_t, size) | |
1da177e4 | 562 | { |
8cc43116 | 563 | return path_getxattr(pathname, name, value, size, 0); |
1da177e4 LT |
564 | } |
565 | ||
64fd1de3 HC |
566 | SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name, |
567 | void __user *, value, size_t, size) | |
1da177e4 | 568 | { |
2903ff01 | 569 | struct fd f = fdget(fd); |
1da177e4 LT |
570 | ssize_t error = -EBADF; |
571 | ||
2903ff01 | 572 | if (!f.file) |
1da177e4 | 573 | return error; |
9f45f5bf | 574 | audit_file(f.file); |
2903ff01 AV |
575 | error = getxattr(f.file->f_path.dentry, name, value, size); |
576 | fdput(f); | |
1da177e4 LT |
577 | return error; |
578 | } | |
579 | ||
580 | /* | |
581 | * Extended attribute LIST operations | |
582 | */ | |
583 | static ssize_t | |
584 | listxattr(struct dentry *d, char __user *list, size_t size) | |
585 | { | |
586 | ssize_t error; | |
587 | char *klist = NULL; | |
588 | ||
589 | if (size) { | |
590 | if (size > XATTR_LIST_MAX) | |
591 | size = XATTR_LIST_MAX; | |
703bf2d1 | 592 | klist = kmalloc(size, __GFP_NOWARN | GFP_KERNEL); |
0d08d7b7 | 593 | if (!klist) { |
0b2a6f23 RW |
594 | klist = vmalloc(size); |
595 | if (!klist) | |
0d08d7b7 | 596 | return -ENOMEM; |
0d08d7b7 | 597 | } |
1da177e4 LT |
598 | } |
599 | ||
659564c8 | 600 | error = vfs_listxattr(d, klist, size); |
f549d6c1 SS |
601 | if (error > 0) { |
602 | if (size && copy_to_user(list, klist, error)) | |
603 | error = -EFAULT; | |
604 | } else if (error == -ERANGE && size >= XATTR_LIST_MAX) { | |
605 | /* The file system tried to returned a list bigger | |
606 | than XATTR_LIST_MAX bytes. Not possible. */ | |
607 | error = -E2BIG; | |
1da177e4 | 608 | } |
0b2a6f23 RW |
609 | |
610 | kvfree(klist); | |
611 | ||
1da177e4 LT |
612 | return error; |
613 | } | |
614 | ||
8cc43116 EB |
615 | static ssize_t path_listxattr(const char __user *pathname, char __user *list, |
616 | size_t size, unsigned int lookup_flags) | |
1da177e4 | 617 | { |
2d8f3038 | 618 | struct path path; |
1da177e4 | 619 | ssize_t error; |
10a90cf3 JL |
620 | retry: |
621 | error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); | |
1da177e4 LT |
622 | if (error) |
623 | return error; | |
2d8f3038 AV |
624 | error = listxattr(path.dentry, list, size); |
625 | path_put(&path); | |
10a90cf3 JL |
626 | if (retry_estale(error, lookup_flags)) { |
627 | lookup_flags |= LOOKUP_REVAL; | |
628 | goto retry; | |
629 | } | |
1da177e4 LT |
630 | return error; |
631 | } | |
632 | ||
8cc43116 EB |
633 | SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list, |
634 | size_t, size) | |
635 | { | |
636 | return path_listxattr(pathname, list, size, LOOKUP_FOLLOW); | |
637 | } | |
638 | ||
64fd1de3 HC |
639 | SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list, |
640 | size_t, size) | |
1da177e4 | 641 | { |
8cc43116 | 642 | return path_listxattr(pathname, list, size, 0); |
1da177e4 LT |
643 | } |
644 | ||
64fd1de3 | 645 | SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size) |
1da177e4 | 646 | { |
2903ff01 | 647 | struct fd f = fdget(fd); |
1da177e4 LT |
648 | ssize_t error = -EBADF; |
649 | ||
2903ff01 | 650 | if (!f.file) |
1da177e4 | 651 | return error; |
9f45f5bf | 652 | audit_file(f.file); |
2903ff01 AV |
653 | error = listxattr(f.file->f_path.dentry, list, size); |
654 | fdput(f); | |
1da177e4 LT |
655 | return error; |
656 | } | |
657 | ||
658 | /* | |
659 | * Extended attribute REMOVE operations | |
660 | */ | |
661 | static long | |
8f0cfa52 | 662 | removexattr(struct dentry *d, const char __user *name) |
1da177e4 LT |
663 | { |
664 | int error; | |
665 | char kname[XATTR_NAME_MAX + 1]; | |
666 | ||
667 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
668 | if (error == 0 || error == sizeof(kname)) | |
669 | error = -ERANGE; | |
670 | if (error < 0) | |
671 | return error; | |
672 | ||
5be196e5 | 673 | return vfs_removexattr(d, kname); |
1da177e4 LT |
674 | } |
675 | ||
8cc43116 EB |
676 | static int path_removexattr(const char __user *pathname, |
677 | const char __user *name, unsigned int lookup_flags) | |
1da177e4 | 678 | { |
2d8f3038 | 679 | struct path path; |
1da177e4 | 680 | int error; |
12f06212 JL |
681 | retry: |
682 | error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); | |
1da177e4 LT |
683 | if (error) |
684 | return error; | |
2d8f3038 | 685 | error = mnt_want_write(path.mnt); |
18f335af | 686 | if (!error) { |
2d8f3038 AV |
687 | error = removexattr(path.dentry, name); |
688 | mnt_drop_write(path.mnt); | |
18f335af | 689 | } |
2d8f3038 | 690 | path_put(&path); |
12f06212 JL |
691 | if (retry_estale(error, lookup_flags)) { |
692 | lookup_flags |= LOOKUP_REVAL; | |
693 | goto retry; | |
694 | } | |
1da177e4 LT |
695 | return error; |
696 | } | |
697 | ||
8cc43116 EB |
698 | SYSCALL_DEFINE2(removexattr, const char __user *, pathname, |
699 | const char __user *, name) | |
700 | { | |
701 | return path_removexattr(pathname, name, LOOKUP_FOLLOW); | |
702 | } | |
703 | ||
6a6160a7 HC |
704 | SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname, |
705 | const char __user *, name) | |
1da177e4 | 706 | { |
8cc43116 | 707 | return path_removexattr(pathname, name, 0); |
1da177e4 LT |
708 | } |
709 | ||
6a6160a7 | 710 | SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name) |
1da177e4 | 711 | { |
2903ff01 | 712 | struct fd f = fdget(fd); |
1da177e4 LT |
713 | int error = -EBADF; |
714 | ||
2903ff01 | 715 | if (!f.file) |
1da177e4 | 716 | return error; |
9f45f5bf | 717 | audit_file(f.file); |
2903ff01 | 718 | error = mnt_want_write_file(f.file); |
18f335af | 719 | if (!error) { |
9f45f5bf | 720 | error = removexattr(f.file->f_path.dentry, name); |
2903ff01 | 721 | mnt_drop_write_file(f.file); |
18f335af | 722 | } |
2903ff01 | 723 | fdput(f); |
1da177e4 LT |
724 | return error; |
725 | } | |
726 | ||
1da177e4 LT |
727 | /* |
728 | * Find the handler for the prefix and dispatch its get() operation. | |
729 | */ | |
730 | ssize_t | |
ce23e640 AV |
731 | generic_getxattr(struct dentry *dentry, struct inode *inode, |
732 | const char *name, void *buffer, size_t size) | |
1da177e4 | 733 | { |
bb435453 | 734 | const struct xattr_handler *handler; |
1da177e4 | 735 | |
d0a5b995 | 736 | handler = xattr_resolve_name(inode, &name); |
98e9cb57 AG |
737 | if (IS_ERR(handler)) |
738 | return PTR_ERR(handler); | |
ce23e640 | 739 | return handler->get(handler, dentry, inode, |
b296821a | 740 | name, buffer, size); |
1da177e4 LT |
741 | } |
742 | ||
743 | /* | |
744 | * Combine the results of the list() operation from every xattr_handler in the | |
745 | * list. | |
746 | */ | |
747 | ssize_t | |
748 | generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) | |
749 | { | |
bb435453 | 750 | const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr; |
1da177e4 LT |
751 | unsigned int size = 0; |
752 | ||
753 | if (!buffer) { | |
431547b3 | 754 | for_each_xattr_handler(handlers, handler) { |
764a5c6b AG |
755 | if (!handler->name || |
756 | (handler->list && !handler->list(dentry))) | |
c4803c49 | 757 | continue; |
764a5c6b | 758 | size += strlen(handler->name) + 1; |
431547b3 | 759 | } |
1da177e4 LT |
760 | } else { |
761 | char *buf = buffer; | |
764a5c6b | 762 | size_t len; |
1da177e4 LT |
763 | |
764 | for_each_xattr_handler(handlers, handler) { | |
764a5c6b AG |
765 | if (!handler->name || |
766 | (handler->list && !handler->list(dentry))) | |
c4803c49 | 767 | continue; |
764a5c6b AG |
768 | len = strlen(handler->name); |
769 | if (len + 1 > buffer_size) | |
1da177e4 | 770 | return -ERANGE; |
764a5c6b AG |
771 | memcpy(buf, handler->name, len + 1); |
772 | buf += len + 1; | |
773 | buffer_size -= len + 1; | |
1da177e4 LT |
774 | } |
775 | size = buf - buffer; | |
776 | } | |
777 | return size; | |
778 | } | |
779 | ||
780 | /* | |
781 | * Find the handler for the prefix and dispatch its set() operation. | |
782 | */ | |
783 | int | |
3767e255 AV |
784 | generic_setxattr(struct dentry *dentry, struct inode *inode, const char *name, |
785 | const void *value, size_t size, int flags) | |
1da177e4 | 786 | { |
bb435453 | 787 | const struct xattr_handler *handler; |
1da177e4 LT |
788 | |
789 | if (size == 0) | |
790 | value = ""; /* empty EA, do not remove */ | |
d0a5b995 | 791 | handler = xattr_resolve_name(inode, &name); |
98e9cb57 AG |
792 | if (IS_ERR(handler)) |
793 | return PTR_ERR(handler); | |
3767e255 | 794 | return handler->set(handler, dentry, inode, name, value, size, flags); |
1da177e4 LT |
795 | } |
796 | ||
797 | /* | |
798 | * Find the handler for the prefix and dispatch its set() operation to remove | |
799 | * any associated extended attribute. | |
800 | */ | |
801 | int | |
802 | generic_removexattr(struct dentry *dentry, const char *name) | |
803 | { | |
bb435453 | 804 | const struct xattr_handler *handler; |
1da177e4 | 805 | |
d0a5b995 | 806 | handler = xattr_resolve_name(d_inode(dentry), &name); |
98e9cb57 AG |
807 | if (IS_ERR(handler)) |
808 | return PTR_ERR(handler); | |
59301226 AV |
809 | return handler->set(handler, dentry, d_inode(dentry), name, NULL, |
810 | 0, XATTR_REPLACE); | |
1da177e4 LT |
811 | } |
812 | ||
813 | EXPORT_SYMBOL(generic_getxattr); | |
814 | EXPORT_SYMBOL(generic_listxattr); | |
815 | EXPORT_SYMBOL(generic_setxattr); | |
816 | EXPORT_SYMBOL(generic_removexattr); | |
38f38657 | 817 | |
e409de99 AG |
818 | /** |
819 | * xattr_full_name - Compute full attribute name from suffix | |
820 | * | |
821 | * @handler: handler of the xattr_handler operation | |
822 | * @name: name passed to the xattr_handler operation | |
823 | * | |
824 | * The get and set xattr handler operations are called with the remainder of | |
825 | * the attribute name after skipping the handler's prefix: for example, "foo" | |
826 | * is passed to the get operation of a handler with prefix "user." to get | |
827 | * attribute "user.foo". The full name is still "there" in the name though. | |
828 | * | |
829 | * Note: the list xattr handler operation when called from the vfs is passed a | |
830 | * NULL name; some file systems use this operation internally, with varying | |
831 | * semantics. | |
832 | */ | |
833 | const char *xattr_full_name(const struct xattr_handler *handler, | |
834 | const char *name) | |
835 | { | |
98e9cb57 | 836 | size_t prefix_len = strlen(xattr_prefix(handler)); |
e409de99 AG |
837 | |
838 | return name - prefix_len; | |
839 | } | |
840 | EXPORT_SYMBOL(xattr_full_name); | |
841 | ||
38f38657 AR |
842 | /* |
843 | * Allocate new xattr and copy in the value; but leave the name to callers. | |
844 | */ | |
845 | struct simple_xattr *simple_xattr_alloc(const void *value, size_t size) | |
846 | { | |
847 | struct simple_xattr *new_xattr; | |
848 | size_t len; | |
849 | ||
850 | /* wrap around? */ | |
851 | len = sizeof(*new_xattr) + size; | |
4e66d445 | 852 | if (len < sizeof(*new_xattr)) |
38f38657 AR |
853 | return NULL; |
854 | ||
855 | new_xattr = kmalloc(len, GFP_KERNEL); | |
856 | if (!new_xattr) | |
857 | return NULL; | |
858 | ||
859 | new_xattr->size = size; | |
860 | memcpy(new_xattr->value, value, size); | |
861 | return new_xattr; | |
862 | } | |
863 | ||
864 | /* | |
865 | * xattr GET operation for in-memory/pseudo filesystems | |
866 | */ | |
867 | int simple_xattr_get(struct simple_xattrs *xattrs, const char *name, | |
868 | void *buffer, size_t size) | |
869 | { | |
870 | struct simple_xattr *xattr; | |
871 | int ret = -ENODATA; | |
872 | ||
873 | spin_lock(&xattrs->lock); | |
874 | list_for_each_entry(xattr, &xattrs->head, list) { | |
875 | if (strcmp(name, xattr->name)) | |
876 | continue; | |
877 | ||
878 | ret = xattr->size; | |
879 | if (buffer) { | |
880 | if (size < xattr->size) | |
881 | ret = -ERANGE; | |
882 | else | |
883 | memcpy(buffer, xattr->value, xattr->size); | |
884 | } | |
885 | break; | |
886 | } | |
887 | spin_unlock(&xattrs->lock); | |
888 | return ret; | |
889 | } | |
890 | ||
aa7c5241 AG |
891 | /** |
892 | * simple_xattr_set - xattr SET operation for in-memory/pseudo filesystems | |
893 | * @xattrs: target simple_xattr list | |
894 | * @name: name of the extended attribute | |
895 | * @value: value of the xattr. If %NULL, will remove the attribute. | |
896 | * @size: size of the new xattr | |
897 | * @flags: %XATTR_{CREATE|REPLACE} | |
898 | * | |
899 | * %XATTR_CREATE is set, the xattr shouldn't exist already; otherwise fails | |
900 | * with -EEXIST. If %XATTR_REPLACE is set, the xattr should exist; | |
901 | * otherwise, fails with -ENODATA. | |
902 | * | |
903 | * Returns 0 on success, -errno on failure. | |
904 | */ | |
905 | int simple_xattr_set(struct simple_xattrs *xattrs, const char *name, | |
906 | const void *value, size_t size, int flags) | |
38f38657 AR |
907 | { |
908 | struct simple_xattr *xattr; | |
43385846 | 909 | struct simple_xattr *new_xattr = NULL; |
38f38657 AR |
910 | int err = 0; |
911 | ||
912 | /* value == NULL means remove */ | |
913 | if (value) { | |
914 | new_xattr = simple_xattr_alloc(value, size); | |
915 | if (!new_xattr) | |
916 | return -ENOMEM; | |
917 | ||
918 | new_xattr->name = kstrdup(name, GFP_KERNEL); | |
919 | if (!new_xattr->name) { | |
920 | kfree(new_xattr); | |
921 | return -ENOMEM; | |
922 | } | |
923 | } | |
924 | ||
925 | spin_lock(&xattrs->lock); | |
926 | list_for_each_entry(xattr, &xattrs->head, list) { | |
927 | if (!strcmp(name, xattr->name)) { | |
928 | if (flags & XATTR_CREATE) { | |
929 | xattr = new_xattr; | |
930 | err = -EEXIST; | |
931 | } else if (new_xattr) { | |
932 | list_replace(&xattr->list, &new_xattr->list); | |
933 | } else { | |
934 | list_del(&xattr->list); | |
935 | } | |
936 | goto out; | |
937 | } | |
938 | } | |
939 | if (flags & XATTR_REPLACE) { | |
940 | xattr = new_xattr; | |
941 | err = -ENODATA; | |
942 | } else { | |
943 | list_add(&new_xattr->list, &xattrs->head); | |
944 | xattr = NULL; | |
945 | } | |
946 | out: | |
947 | spin_unlock(&xattrs->lock); | |
948 | if (xattr) { | |
949 | kfree(xattr->name); | |
950 | kfree(xattr); | |
951 | } | |
952 | return err; | |
953 | ||
954 | } | |
955 | ||
38f38657 AR |
956 | static bool xattr_is_trusted(const char *name) |
957 | { | |
958 | return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN); | |
959 | } | |
960 | ||
786534b9 AG |
961 | static int xattr_list_one(char **buffer, ssize_t *remaining_size, |
962 | const char *name) | |
963 | { | |
964 | size_t len = strlen(name) + 1; | |
965 | if (*buffer) { | |
966 | if (*remaining_size < len) | |
967 | return -ERANGE; | |
968 | memcpy(*buffer, name, len); | |
969 | *buffer += len; | |
970 | } | |
971 | *remaining_size -= len; | |
972 | return 0; | |
973 | } | |
974 | ||
38f38657 AR |
975 | /* |
976 | * xattr LIST operation for in-memory/pseudo filesystems | |
977 | */ | |
786534b9 AG |
978 | ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs, |
979 | char *buffer, size_t size) | |
38f38657 AR |
980 | { |
981 | bool trusted = capable(CAP_SYS_ADMIN); | |
982 | struct simple_xattr *xattr; | |
786534b9 | 983 | ssize_t remaining_size = size; |
0e9a7da5 | 984 | int err = 0; |
786534b9 AG |
985 | |
986 | #ifdef CONFIG_FS_POSIX_ACL | |
987 | if (inode->i_acl) { | |
988 | err = xattr_list_one(&buffer, &remaining_size, | |
989 | XATTR_NAME_POSIX_ACL_ACCESS); | |
990 | if (err) | |
991 | return err; | |
992 | } | |
993 | if (inode->i_default_acl) { | |
994 | err = xattr_list_one(&buffer, &remaining_size, | |
995 | XATTR_NAME_POSIX_ACL_DEFAULT); | |
996 | if (err) | |
997 | return err; | |
998 | } | |
999 | #endif | |
38f38657 AR |
1000 | |
1001 | spin_lock(&xattrs->lock); | |
1002 | list_for_each_entry(xattr, &xattrs->head, list) { | |
38f38657 AR |
1003 | /* skip "trusted." attributes for unprivileged callers */ |
1004 | if (!trusted && xattr_is_trusted(xattr->name)) | |
1005 | continue; | |
1006 | ||
786534b9 AG |
1007 | err = xattr_list_one(&buffer, &remaining_size, xattr->name); |
1008 | if (err) | |
0e9a7da5 | 1009 | break; |
38f38657 AR |
1010 | } |
1011 | spin_unlock(&xattrs->lock); | |
1012 | ||
0e9a7da5 | 1013 | return err ? err : size - remaining_size; |
38f38657 AR |
1014 | } |
1015 | ||
4895768b AR |
1016 | /* |
1017 | * Adds an extended attribute to the list | |
1018 | */ | |
38f38657 AR |
1019 | void simple_xattr_list_add(struct simple_xattrs *xattrs, |
1020 | struct simple_xattr *new_xattr) | |
1021 | { | |
1022 | spin_lock(&xattrs->lock); | |
1023 | list_add(&new_xattr->list, &xattrs->head); | |
1024 | spin_unlock(&xattrs->lock); | |
1025 | } |