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CommitLineData
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
27static const char *
28strcmp_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 */
52static const struct xattr_handler *
d0a5b995 53xattr_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 */
84static int
85xattr_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
136int
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}
151EXPORT_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 */
169int __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}
205
206
207int
208vfs_setxattr(struct dentry *dentry, const char *name, const void *value,
209 size_t size, int flags)
210{
211 struct inode *inode = dentry->d_inode;
212 int error;
213
214 error = xattr_permission(inode, name, MAY_WRITE);
215 if (error)
216 return error;
217
5955102c 218 inode_lock(inode);
b1ab7e4b
DQ
219 error = security_inode_setxattr(dentry, name, value, size, flags);
220 if (error)
221 goto out;
222
223 error = __vfs_setxattr_noperm(dentry, name, value, size, flags);
224
5be196e5 225out:
5955102c 226 inode_unlock(inode);
5be196e5
CH
227 return error;
228}
229EXPORT_SYMBOL_GPL(vfs_setxattr);
230
2220c5b0 231static ssize_t
42492594
DQ
232xattr_getsecurity(struct inode *inode, const char *name, void *value,
233 size_t size)
234{
235 void *buffer = NULL;
236 ssize_t len;
237
238 if (!value || !size) {
239 len = security_inode_getsecurity(inode, name, &buffer, false);
240 goto out_noalloc;
241 }
242
243 len = security_inode_getsecurity(inode, name, &buffer, true);
244 if (len < 0)
245 return len;
246 if (size < len) {
247 len = -ERANGE;
248 goto out;
249 }
250 memcpy(value, buffer, len);
251out:
57e7ba04 252 kfree(buffer);
42492594
DQ
253out_noalloc:
254 return len;
255}
42492594 256
1601fbad
MZ
257/*
258 * vfs_getxattr_alloc - allocate memory, if necessary, before calling getxattr
259 *
260 * Allocate memory, if not already allocated, or re-allocate correct size,
261 * before retrieving the extended attribute.
262 *
263 * Returns the result of alloc, if failed, or the getxattr operation.
264 */
265ssize_t
266vfs_getxattr_alloc(struct dentry *dentry, const char *name, char **xattr_value,
267 size_t xattr_size, gfp_t flags)
268{
6c6ef9f2 269 const struct xattr_handler *handler;
1601fbad
MZ
270 struct inode *inode = dentry->d_inode;
271 char *value = *xattr_value;
272 int error;
273
274 error = xattr_permission(inode, name, MAY_READ);
275 if (error)
276 return error;
277
6c6ef9f2
AG
278 handler = xattr_resolve_name(inode, &name);
279 if (IS_ERR(handler))
280 return PTR_ERR(handler);
281 if (!handler->get)
1601fbad 282 return -EOPNOTSUPP;
6c6ef9f2 283 error = handler->get(handler, dentry, inode, name, NULL, 0);
1601fbad
MZ
284 if (error < 0)
285 return error;
286
287 if (!value || (error > xattr_size)) {
288 value = krealloc(*xattr_value, error + 1, flags);
289 if (!value)
290 return -ENOMEM;
291 memset(value, 0, error + 1);
292 }
293
6c6ef9f2 294 error = handler->get(handler, dentry, inode, name, value, error);
1601fbad
MZ
295 *xattr_value = value;
296 return error;
297}
298
5d6c3191
AG
299ssize_t
300__vfs_getxattr(struct dentry *dentry, struct inode *inode, const char *name,
301 void *value, size_t size)
302{
6c6ef9f2
AG
303 const struct xattr_handler *handler;
304
305 handler = xattr_resolve_name(inode, &name);
306 if (IS_ERR(handler))
307 return PTR_ERR(handler);
308 if (!handler->get)
5d6c3191 309 return -EOPNOTSUPP;
6c6ef9f2 310 return handler->get(handler, dentry, inode, name, value, size);
5d6c3191
AG
311}
312EXPORT_SYMBOL(__vfs_getxattr);
313
5be196e5 314ssize_t
8f0cfa52 315vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size)
5be196e5
CH
316{
317 struct inode *inode = dentry->d_inode;
318 int error;
319
e0ad7b07 320 error = xattr_permission(inode, name, MAY_READ);
321 if (error)
322 return error;
323
5be196e5
CH
324 error = security_inode_getxattr(dentry, name);
325 if (error)
326 return error;
327
5be196e5 328 if (!strncmp(name, XATTR_SECURITY_PREFIX,
e0ad7b07 329 XATTR_SECURITY_PREFIX_LEN)) {
330 const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
42492594 331 int ret = xattr_getsecurity(inode, suffix, value, size);
5be196e5
CH
332 /*
333 * Only overwrite the return value if a security module
334 * is actually active.
335 */
4bea5805
DQ
336 if (ret == -EOPNOTSUPP)
337 goto nolsm;
338 return ret;
5be196e5 339 }
4bea5805 340nolsm:
5d6c3191 341 return __vfs_getxattr(dentry, inode, name, value, size);
5be196e5
CH
342}
343EXPORT_SYMBOL_GPL(vfs_getxattr);
344
659564c8 345ssize_t
bf3ee713 346vfs_listxattr(struct dentry *dentry, char *list, size_t size)
659564c8 347{
bf3ee713 348 struct inode *inode = d_inode(dentry);
659564c8
BN
349 ssize_t error;
350
bf3ee713 351 error = security_inode_listxattr(dentry);
659564c8
BN
352 if (error)
353 return error;
bf3ee713 354 if (inode->i_op->listxattr && (inode->i_opflags & IOP_XATTR)) {
bf3ee713 355 error = inode->i_op->listxattr(dentry, list, size);
659564c8 356 } else {
bf3ee713 357 error = security_inode_listsecurity(inode, list, size);
659564c8
BN
358 if (size && error > size)
359 error = -ERANGE;
360 }
361 return error;
362}
363EXPORT_SYMBOL_GPL(vfs_listxattr);
364
5be196e5 365int
5d6c3191 366__vfs_removexattr(struct dentry *dentry, const char *name)
5be196e5 367{
6c6ef9f2
AG
368 struct inode *inode = d_inode(dentry);
369 const struct xattr_handler *handler;
5be196e5 370
6c6ef9f2
AG
371 handler = xattr_resolve_name(inode, &name);
372 if (IS_ERR(handler))
373 return PTR_ERR(handler);
374 if (!handler->set)
5be196e5 375 return -EOPNOTSUPP;
6c6ef9f2 376 return handler->set(handler, dentry, inode, name, NULL, 0, XATTR_REPLACE);
5d6c3191
AG
377}
378EXPORT_SYMBOL(__vfs_removexattr);
379
380int
381vfs_removexattr(struct dentry *dentry, const char *name)
382{
383 struct inode *inode = dentry->d_inode;
384 int error;
5be196e5 385
e0ad7b07 386 error = xattr_permission(inode, name, MAY_WRITE);
387 if (error)
388 return error;
389
5955102c 390 inode_lock(inode);
5be196e5 391 error = security_inode_removexattr(dentry, name);
7c51bb00
DK
392 if (error)
393 goto out;
5be196e5 394
5d6c3191 395 error = __vfs_removexattr(dentry, name);
5be196e5 396
c7b87de2 397 if (!error) {
5be196e5 398 fsnotify_xattr(dentry);
c7b87de2
MZ
399 evm_inode_post_removexattr(dentry, name);
400 }
7c51bb00
DK
401
402out:
5955102c 403 inode_unlock(inode);
5be196e5
CH
404 return error;
405}
406EXPORT_SYMBOL_GPL(vfs_removexattr);
407
408
1da177e4
LT
409/*
410 * Extended attribute SET operations
411 */
412static long
8f0cfa52 413setxattr(struct dentry *d, const char __user *name, const void __user *value,
1da177e4
LT
414 size_t size, int flags)
415{
416 int error;
417 void *kvalue = NULL;
418 char kname[XATTR_NAME_MAX + 1];
419
420 if (flags & ~(XATTR_CREATE|XATTR_REPLACE))
421 return -EINVAL;
422
423 error = strncpy_from_user(kname, name, sizeof(kname));
424 if (error == 0 || error == sizeof(kname))
425 error = -ERANGE;
426 if (error < 0)
427 return error;
428
429 if (size) {
430 if (size > XATTR_SIZE_MAX)
431 return -E2BIG;
752ade68
MH
432 kvalue = kvmalloc(size, GFP_KERNEL);
433 if (!kvalue)
434 return -ENOMEM;
44c82498
AM
435 if (copy_from_user(kvalue, value, size)) {
436 error = -EFAULT;
437 goto out;
438 }
2f6f0654
EB
439 if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
440 (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
441 posix_acl_fix_xattr_from_user(kvalue, size);
8db6c34f
SH
442 else if (strcmp(kname, XATTR_NAME_CAPS) == 0) {
443 error = cap_convert_nscap(d, &kvalue, size);
444 if (error < 0)
445 goto out;
446 size = error;
447 }
1da177e4
LT
448 }
449
5be196e5 450 error = vfs_setxattr(d, kname, kvalue, size, flags);
44c82498 451out:
0b2a6f23
RW
452 kvfree(kvalue);
453
1da177e4
LT
454 return error;
455}
456
8cc43116
EB
457static int path_setxattr(const char __user *pathname,
458 const char __user *name, const void __user *value,
459 size_t size, int flags, unsigned int lookup_flags)
1da177e4 460{
2d8f3038 461 struct path path;
1da177e4 462 int error;
68f1bb8b
JL
463retry:
464 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
1da177e4
LT
465 if (error)
466 return error;
2d8f3038 467 error = mnt_want_write(path.mnt);
18f335af 468 if (!error) {
2d8f3038
AV
469 error = setxattr(path.dentry, name, value, size, flags);
470 mnt_drop_write(path.mnt);
18f335af 471 }
2d8f3038 472 path_put(&path);
68f1bb8b
JL
473 if (retry_estale(error, lookup_flags)) {
474 lookup_flags |= LOOKUP_REVAL;
475 goto retry;
476 }
1da177e4
LT
477 return error;
478}
479
8cc43116
EB
480SYSCALL_DEFINE5(setxattr, const char __user *, pathname,
481 const char __user *, name, const void __user *, value,
482 size_t, size, int, flags)
483{
484 return path_setxattr(pathname, name, value, size, flags, LOOKUP_FOLLOW);
485}
486
64fd1de3
HC
487SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname,
488 const char __user *, name, const void __user *, value,
489 size_t, size, int, flags)
1da177e4 490{
8cc43116 491 return path_setxattr(pathname, name, value, size, flags, 0);
1da177e4
LT
492}
493
64fd1de3
HC
494SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
495 const void __user *,value, size_t, size, int, flags)
1da177e4 496{
2903ff01 497 struct fd f = fdget(fd);
1da177e4
LT
498 int error = -EBADF;
499
2903ff01 500 if (!f.file)
1da177e4 501 return error;
9f45f5bf 502 audit_file(f.file);
6742cee0 503 error = mnt_want_write_file(f.file);
18f335af 504 if (!error) {
9f45f5bf 505 error = setxattr(f.file->f_path.dentry, name, value, size, flags);
6742cee0 506 mnt_drop_write_file(f.file);
18f335af 507 }
2903ff01 508 fdput(f);
1da177e4
LT
509 return error;
510}
511
512/*
513 * Extended attribute GET operations
514 */
515static ssize_t
8f0cfa52
DH
516getxattr(struct dentry *d, const char __user *name, void __user *value,
517 size_t size)
1da177e4
LT
518{
519 ssize_t error;
520 void *kvalue = NULL;
521 char kname[XATTR_NAME_MAX + 1];
522
523 error = strncpy_from_user(kname, name, sizeof(kname));
524 if (error == 0 || error == sizeof(kname))
525 error = -ERANGE;
526 if (error < 0)
527 return error;
528
529 if (size) {
530 if (size > XATTR_SIZE_MAX)
531 size = XATTR_SIZE_MAX;
752ade68
MH
532 kvalue = kvzalloc(size, GFP_KERNEL);
533 if (!kvalue)
534 return -ENOMEM;
1da177e4
LT
535 }
536
5be196e5 537 error = vfs_getxattr(d, kname, kvalue, size);
f549d6c1 538 if (error > 0) {
2f6f0654
EB
539 if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
540 (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
82c9a927 541 posix_acl_fix_xattr_to_user(kvalue, error);
f549d6c1
SS
542 if (size && copy_to_user(value, kvalue, error))
543 error = -EFAULT;
544 } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) {
545 /* The file system tried to returned a value bigger
546 than XATTR_SIZE_MAX bytes. Not possible. */
547 error = -E2BIG;
1da177e4 548 }
0b2a6f23
RW
549
550 kvfree(kvalue);
551
1da177e4
LT
552 return error;
553}
554
8cc43116
EB
555static ssize_t path_getxattr(const char __user *pathname,
556 const char __user *name, void __user *value,
557 size_t size, unsigned int lookup_flags)
1da177e4 558{
2d8f3038 559 struct path path;
1da177e4 560 ssize_t error;
60e66b48
JL
561retry:
562 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
1da177e4
LT
563 if (error)
564 return error;
2d8f3038
AV
565 error = getxattr(path.dentry, name, value, size);
566 path_put(&path);
60e66b48
JL
567 if (retry_estale(error, lookup_flags)) {
568 lookup_flags |= LOOKUP_REVAL;
569 goto retry;
570 }
1da177e4
LT
571 return error;
572}
573
8cc43116
EB
574SYSCALL_DEFINE4(getxattr, const char __user *, pathname,
575 const char __user *, name, void __user *, value, size_t, size)
576{
577 return path_getxattr(pathname, name, value, size, LOOKUP_FOLLOW);
578}
579
64fd1de3
HC
580SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname,
581 const char __user *, name, void __user *, value, size_t, size)
1da177e4 582{
8cc43116 583 return path_getxattr(pathname, name, value, size, 0);
1da177e4
LT
584}
585
64fd1de3
HC
586SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name,
587 void __user *, value, size_t, size)
1da177e4 588{
2903ff01 589 struct fd f = fdget(fd);
1da177e4
LT
590 ssize_t error = -EBADF;
591
2903ff01 592 if (!f.file)
1da177e4 593 return error;
9f45f5bf 594 audit_file(f.file);
2903ff01
AV
595 error = getxattr(f.file->f_path.dentry, name, value, size);
596 fdput(f);
1da177e4
LT
597 return error;
598}
599
600/*
601 * Extended attribute LIST operations
602 */
603static ssize_t
604listxattr(struct dentry *d, char __user *list, size_t size)
605{
606 ssize_t error;
607 char *klist = NULL;
608
609 if (size) {
610 if (size > XATTR_LIST_MAX)
611 size = XATTR_LIST_MAX;
752ade68
MH
612 klist = kvmalloc(size, GFP_KERNEL);
613 if (!klist)
614 return -ENOMEM;
1da177e4
LT
615 }
616
659564c8 617 error = vfs_listxattr(d, klist, size);
f549d6c1
SS
618 if (error > 0) {
619 if (size && copy_to_user(list, klist, error))
620 error = -EFAULT;
621 } else if (error == -ERANGE && size >= XATTR_LIST_MAX) {
622 /* The file system tried to returned a list bigger
623 than XATTR_LIST_MAX bytes. Not possible. */
624 error = -E2BIG;
1da177e4 625 }
0b2a6f23
RW
626
627 kvfree(klist);
628
1da177e4
LT
629 return error;
630}
631
8cc43116
EB
632static ssize_t path_listxattr(const char __user *pathname, char __user *list,
633 size_t size, unsigned int lookup_flags)
1da177e4 634{
2d8f3038 635 struct path path;
1da177e4 636 ssize_t error;
10a90cf3
JL
637retry:
638 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
1da177e4
LT
639 if (error)
640 return error;
2d8f3038
AV
641 error = listxattr(path.dentry, list, size);
642 path_put(&path);
10a90cf3
JL
643 if (retry_estale(error, lookup_flags)) {
644 lookup_flags |= LOOKUP_REVAL;
645 goto retry;
646 }
1da177e4
LT
647 return error;
648}
649
8cc43116
EB
650SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list,
651 size_t, size)
652{
653 return path_listxattr(pathname, list, size, LOOKUP_FOLLOW);
654}
655
64fd1de3
HC
656SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list,
657 size_t, size)
1da177e4 658{
8cc43116 659 return path_listxattr(pathname, list, size, 0);
1da177e4
LT
660}
661
64fd1de3 662SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size)
1da177e4 663{
2903ff01 664 struct fd f = fdget(fd);
1da177e4
LT
665 ssize_t error = -EBADF;
666
2903ff01 667 if (!f.file)
1da177e4 668 return error;
9f45f5bf 669 audit_file(f.file);
2903ff01
AV
670 error = listxattr(f.file->f_path.dentry, list, size);
671 fdput(f);
1da177e4
LT
672 return error;
673}
674
675/*
676 * Extended attribute REMOVE operations
677 */
678static long
8f0cfa52 679removexattr(struct dentry *d, const char __user *name)
1da177e4
LT
680{
681 int error;
682 char kname[XATTR_NAME_MAX + 1];
683
684 error = strncpy_from_user(kname, name, sizeof(kname));
685 if (error == 0 || error == sizeof(kname))
686 error = -ERANGE;
687 if (error < 0)
688 return error;
689
5be196e5 690 return vfs_removexattr(d, kname);
1da177e4
LT
691}
692
8cc43116
EB
693static int path_removexattr(const char __user *pathname,
694 const char __user *name, unsigned int lookup_flags)
1da177e4 695{
2d8f3038 696 struct path path;
1da177e4 697 int error;
12f06212
JL
698retry:
699 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
1da177e4
LT
700 if (error)
701 return error;
2d8f3038 702 error = mnt_want_write(path.mnt);
18f335af 703 if (!error) {
2d8f3038
AV
704 error = removexattr(path.dentry, name);
705 mnt_drop_write(path.mnt);
18f335af 706 }
2d8f3038 707 path_put(&path);
12f06212
JL
708 if (retry_estale(error, lookup_flags)) {
709 lookup_flags |= LOOKUP_REVAL;
710 goto retry;
711 }
1da177e4
LT
712 return error;
713}
714
8cc43116
EB
715SYSCALL_DEFINE2(removexattr, const char __user *, pathname,
716 const char __user *, name)
717{
718 return path_removexattr(pathname, name, LOOKUP_FOLLOW);
719}
720
6a6160a7
HC
721SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname,
722 const char __user *, name)
1da177e4 723{
8cc43116 724 return path_removexattr(pathname, name, 0);
1da177e4
LT
725}
726
6a6160a7 727SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name)
1da177e4 728{
2903ff01 729 struct fd f = fdget(fd);
1da177e4
LT
730 int error = -EBADF;
731
2903ff01 732 if (!f.file)
1da177e4 733 return error;
9f45f5bf 734 audit_file(f.file);
6742cee0 735 error = mnt_want_write_file(f.file);
18f335af 736 if (!error) {
9f45f5bf 737 error = removexattr(f.file->f_path.dentry, name);
6742cee0 738 mnt_drop_write_file(f.file);
18f335af 739 }
2903ff01 740 fdput(f);
1da177e4
LT
741 return error;
742}
743
1da177e4
LT
744/*
745 * Combine the results of the list() operation from every xattr_handler in the
746 * list.
747 */
748ssize_t
749generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
750{
bb435453 751 const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr;
1da177e4
LT
752 unsigned int size = 0;
753
754 if (!buffer) {
431547b3 755 for_each_xattr_handler(handlers, handler) {
764a5c6b
AG
756 if (!handler->name ||
757 (handler->list && !handler->list(dentry)))
c4803c49 758 continue;
764a5c6b 759 size += strlen(handler->name) + 1;
431547b3 760 }
1da177e4
LT
761 } else {
762 char *buf = buffer;
764a5c6b 763 size_t len;
1da177e4
LT
764
765 for_each_xattr_handler(handlers, handler) {
764a5c6b
AG
766 if (!handler->name ||
767 (handler->list && !handler->list(dentry)))
c4803c49 768 continue;
764a5c6b
AG
769 len = strlen(handler->name);
770 if (len + 1 > buffer_size)
1da177e4 771 return -ERANGE;
764a5c6b
AG
772 memcpy(buf, handler->name, len + 1);
773 buf += len + 1;
774 buffer_size -= len + 1;
1da177e4
LT
775 }
776 size = buf - buffer;
777 }
778 return size;
779}
1da177e4 780EXPORT_SYMBOL(generic_listxattr);
38f38657 781
e409de99
AG
782/**
783 * xattr_full_name - Compute full attribute name from suffix
784 *
785 * @handler: handler of the xattr_handler operation
786 * @name: name passed to the xattr_handler operation
787 *
788 * The get and set xattr handler operations are called with the remainder of
789 * the attribute name after skipping the handler's prefix: for example, "foo"
790 * is passed to the get operation of a handler with prefix "user." to get
791 * attribute "user.foo". The full name is still "there" in the name though.
792 *
793 * Note: the list xattr handler operation when called from the vfs is passed a
794 * NULL name; some file systems use this operation internally, with varying
795 * semantics.
796 */
797const char *xattr_full_name(const struct xattr_handler *handler,
798 const char *name)
799{
98e9cb57 800 size_t prefix_len = strlen(xattr_prefix(handler));
e409de99
AG
801
802 return name - prefix_len;
803}
804EXPORT_SYMBOL(xattr_full_name);
805
38f38657
AR
806/*
807 * Allocate new xattr and copy in the value; but leave the name to callers.
808 */
809struct simple_xattr *simple_xattr_alloc(const void *value, size_t size)
810{
811 struct simple_xattr *new_xattr;
812 size_t len;
813
814 /* wrap around? */
815 len = sizeof(*new_xattr) + size;
4e66d445 816 if (len < sizeof(*new_xattr))
38f38657
AR
817 return NULL;
818
819 new_xattr = kmalloc(len, GFP_KERNEL);
820 if (!new_xattr)
821 return NULL;
822
823 new_xattr->size = size;
824 memcpy(new_xattr->value, value, size);
825 return new_xattr;
826}
827
828/*
829 * xattr GET operation for in-memory/pseudo filesystems
830 */
831int simple_xattr_get(struct simple_xattrs *xattrs, const char *name,
832 void *buffer, size_t size)
833{
834 struct simple_xattr *xattr;
835 int ret = -ENODATA;
836
837 spin_lock(&xattrs->lock);
838 list_for_each_entry(xattr, &xattrs->head, list) {
839 if (strcmp(name, xattr->name))
840 continue;
841
842 ret = xattr->size;
843 if (buffer) {
844 if (size < xattr->size)
845 ret = -ERANGE;
846 else
847 memcpy(buffer, xattr->value, xattr->size);
848 }
849 break;
850 }
851 spin_unlock(&xattrs->lock);
852 return ret;
853}
854
aa7c5241
AG
855/**
856 * simple_xattr_set - xattr SET operation for in-memory/pseudo filesystems
857 * @xattrs: target simple_xattr list
858 * @name: name of the extended attribute
859 * @value: value of the xattr. If %NULL, will remove the attribute.
860 * @size: size of the new xattr
861 * @flags: %XATTR_{CREATE|REPLACE}
862 *
863 * %XATTR_CREATE is set, the xattr shouldn't exist already; otherwise fails
864 * with -EEXIST. If %XATTR_REPLACE is set, the xattr should exist;
865 * otherwise, fails with -ENODATA.
866 *
867 * Returns 0 on success, -errno on failure.
868 */
869int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,
870 const void *value, size_t size, int flags)
38f38657
AR
871{
872 struct simple_xattr *xattr;
43385846 873 struct simple_xattr *new_xattr = NULL;
38f38657
AR
874 int err = 0;
875
876 /* value == NULL means remove */
877 if (value) {
878 new_xattr = simple_xattr_alloc(value, size);
879 if (!new_xattr)
880 return -ENOMEM;
881
882 new_xattr->name = kstrdup(name, GFP_KERNEL);
883 if (!new_xattr->name) {
884 kfree(new_xattr);
885 return -ENOMEM;
886 }
887 }
888
889 spin_lock(&xattrs->lock);
890 list_for_each_entry(xattr, &xattrs->head, list) {
891 if (!strcmp(name, xattr->name)) {
892 if (flags & XATTR_CREATE) {
893 xattr = new_xattr;
894 err = -EEXIST;
895 } else if (new_xattr) {
896 list_replace(&xattr->list, &new_xattr->list);
897 } else {
898 list_del(&xattr->list);
899 }
900 goto out;
901 }
902 }
903 if (flags & XATTR_REPLACE) {
904 xattr = new_xattr;
905 err = -ENODATA;
906 } else {
907 list_add(&new_xattr->list, &xattrs->head);
908 xattr = NULL;
909 }
910out:
911 spin_unlock(&xattrs->lock);
912 if (xattr) {
913 kfree(xattr->name);
914 kfree(xattr);
915 }
916 return err;
917
918}
919
38f38657
AR
920static bool xattr_is_trusted(const char *name)
921{
922 return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN);
923}
924
786534b9
AG
925static int xattr_list_one(char **buffer, ssize_t *remaining_size,
926 const char *name)
927{
928 size_t len = strlen(name) + 1;
929 if (*buffer) {
930 if (*remaining_size < len)
931 return -ERANGE;
932 memcpy(*buffer, name, len);
933 *buffer += len;
934 }
935 *remaining_size -= len;
936 return 0;
937}
938
38f38657
AR
939/*
940 * xattr LIST operation for in-memory/pseudo filesystems
941 */
786534b9
AG
942ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs,
943 char *buffer, size_t size)
38f38657
AR
944{
945 bool trusted = capable(CAP_SYS_ADMIN);
946 struct simple_xattr *xattr;
786534b9 947 ssize_t remaining_size = size;
0e9a7da5 948 int err = 0;
786534b9
AG
949
950#ifdef CONFIG_FS_POSIX_ACL
951 if (inode->i_acl) {
952 err = xattr_list_one(&buffer, &remaining_size,
953 XATTR_NAME_POSIX_ACL_ACCESS);
954 if (err)
955 return err;
956 }
957 if (inode->i_default_acl) {
958 err = xattr_list_one(&buffer, &remaining_size,
959 XATTR_NAME_POSIX_ACL_DEFAULT);
960 if (err)
961 return err;
962 }
963#endif
38f38657
AR
964
965 spin_lock(&xattrs->lock);
966 list_for_each_entry(xattr, &xattrs->head, list) {
38f38657
AR
967 /* skip "trusted." attributes for unprivileged callers */
968 if (!trusted && xattr_is_trusted(xattr->name))
969 continue;
970
786534b9
AG
971 err = xattr_list_one(&buffer, &remaining_size, xattr->name);
972 if (err)
0e9a7da5 973 break;
38f38657
AR
974 }
975 spin_unlock(&xattrs->lock);
976
0e9a7da5 977 return err ? err : size - remaining_size;
38f38657
AR
978}
979
4895768b
AR
980/*
981 * Adds an extended attribute to the list
982 */
38f38657
AR
983void simple_xattr_list_add(struct simple_xattrs *xattrs,
984 struct simple_xattr *new_xattr)
985{
986 spin_lock(&xattrs->lock);
987 list_add(&new_xattr->list, &xattrs->head);
988 spin_unlock(&xattrs->lock);
989}