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11#include <linux/fs.h>
12#include <linux/slab.h>
13#include <linux/file.h>
14#include <linux/xattr.h>
15#include <linux/mount.h>
16#include <linux/namei.h>
17#include <linux/security.h>
18#include <linux/evm.h>
19#include <linux/syscalls.h>
20#include <linux/export.h>
21#include <linux/fsnotify.h>
22#include <linux/audit.h>
23#include <linux/vmalloc.h>
24#include <linux/posix_acl_xattr.h>
25
26#include <linux/uaccess.h>
27
28static const char *
29strcmp_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
40
41
42
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
52
53static const struct xattr_handler *
54xattr_resolve_name(struct inode *inode, const char **name)
55{
56 const struct xattr_handler **handlers = inode->i_sb->s_xattr;
57 const struct xattr_handler *handler;
58
59 if (!(inode->i_opflags & IOP_XATTR)) {
60 if (unlikely(is_bad_inode(inode)))
61 return ERR_PTR(-EIO);
62 return ERR_PTR(-EOPNOTSUPP);
63 }
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
81
82
83
84
85static int
86xattr_permission(struct user_namespace *mnt_userns, struct inode *inode,
87 const char *name, int mask)
88{
89
90
91
92
93 if (mask & MAY_WRITE) {
94 if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
95 return -EPERM;
96
97
98
99
100
101 if (HAS_UNMAPPED_ID(mnt_userns, inode))
102 return -EPERM;
103 }
104
105
106
107
108
109 if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) ||
110 !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
111 return 0;
112
113
114
115
116 if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) {
117 if (!capable(CAP_SYS_ADMIN))
118 return (mask & MAY_WRITE) ? -EPERM : -ENODATA;
119 return 0;
120 }
121
122
123
124
125
126
127 if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) {
128 if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
129 return (mask & MAY_WRITE) ? -EPERM : -ENODATA;
130 if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) &&
131 (mask & MAY_WRITE) &&
132 !inode_owner_or_capable(mnt_userns, inode))
133 return -EPERM;
134 }
135
136 return inode_permission(mnt_userns, inode, mask);
137}
138
139
140
141
142int
143xattr_supported_namespace(struct inode *inode, const char *prefix)
144{
145 const struct xattr_handler **handlers = inode->i_sb->s_xattr;
146 const struct xattr_handler *handler;
147 size_t preflen;
148
149 if (!(inode->i_opflags & IOP_XATTR)) {
150 if (unlikely(is_bad_inode(inode)))
151 return -EIO;
152 return -EOPNOTSUPP;
153 }
154
155 preflen = strlen(prefix);
156
157 for_each_xattr_handler(handlers, handler) {
158 if (!strncmp(xattr_prefix(handler), prefix, preflen))
159 return 0;
160 }
161
162 return -EOPNOTSUPP;
163}
164EXPORT_SYMBOL(xattr_supported_namespace);
165
166int
167__vfs_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry,
168 struct inode *inode, const char *name, const void *value,
169 size_t size, int flags)
170{
171 const struct xattr_handler *handler;
172
173 handler = xattr_resolve_name(inode, &name);
174 if (IS_ERR(handler))
175 return PTR_ERR(handler);
176 if (!handler->set)
177 return -EOPNOTSUPP;
178 if (size == 0)
179 value = "";
180 return handler->set(handler, mnt_userns, dentry, inode, name, value,
181 size, flags);
182}
183EXPORT_SYMBOL(__vfs_setxattr);
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202int __vfs_setxattr_noperm(struct user_namespace *mnt_userns,
203 struct dentry *dentry, const char *name,
204 const void *value, size_t size, int flags)
205{
206 struct inode *inode = dentry->d_inode;
207 int error = -EAGAIN;
208 int issec = !strncmp(name, XATTR_SECURITY_PREFIX,
209 XATTR_SECURITY_PREFIX_LEN);
210
211 if (issec)
212 inode->i_flags &= ~S_NOSEC;
213 if (inode->i_opflags & IOP_XATTR) {
214 error = __vfs_setxattr(mnt_userns, dentry, inode, name, value,
215 size, flags);
216 if (!error) {
217 fsnotify_xattr(dentry);
218 security_inode_post_setxattr(dentry, name, value,
219 size, flags);
220 }
221 } else {
222 if (unlikely(is_bad_inode(inode)))
223 return -EIO;
224 }
225 if (error == -EAGAIN) {
226 error = -EOPNOTSUPP;
227
228 if (issec) {
229 const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
230
231 error = security_inode_setsecurity(inode, suffix, value,
232 size, flags);
233 if (!error)
234 fsnotify_xattr(dentry);
235 }
236 }
237
238 return error;
239}
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254int
255__vfs_setxattr_locked(struct user_namespace *mnt_userns, struct dentry *dentry,
256 const char *name, const void *value, size_t size,
257 int flags, struct inode **delegated_inode)
258{
259 struct inode *inode = dentry->d_inode;
260 int error;
261
262 error = xattr_permission(mnt_userns, inode, name, MAY_WRITE);
263 if (error)
264 return error;
265
266 error = security_inode_setxattr(mnt_userns, dentry, name, value, size,
267 flags);
268 if (error)
269 goto out;
270
271 error = try_break_deleg(inode, delegated_inode);
272 if (error)
273 goto out;
274
275 error = __vfs_setxattr_noperm(mnt_userns, dentry, name, value,
276 size, flags);
277
278out:
279 return error;
280}
281EXPORT_SYMBOL_GPL(__vfs_setxattr_locked);
282
283int
284vfs_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry,
285 const char *name, const void *value, size_t size, int flags)
286{
287 struct inode *inode = dentry->d_inode;
288 struct inode *delegated_inode = NULL;
289 const void *orig_value = value;
290 int error;
291
292 if (size && strcmp(name, XATTR_NAME_CAPS) == 0) {
293 error = cap_convert_nscap(mnt_userns, dentry, &value, size);
294 if (error < 0)
295 return error;
296 size = error;
297 }
298
299retry_deleg:
300 inode_lock(inode);
301 error = __vfs_setxattr_locked(mnt_userns, dentry, name, value, size,
302 flags, &delegated_inode);
303 inode_unlock(inode);
304
305 if (delegated_inode) {
306 error = break_deleg_wait(&delegated_inode);
307 if (!error)
308 goto retry_deleg;
309 }
310 if (value != orig_value)
311 kfree(value);
312
313 return error;
314}
315EXPORT_SYMBOL_GPL(vfs_setxattr);
316
317static ssize_t
318xattr_getsecurity(struct user_namespace *mnt_userns, struct inode *inode,
319 const char *name, void *value, size_t size)
320{
321 void *buffer = NULL;
322 ssize_t len;
323
324 if (!value || !size) {
325 len = security_inode_getsecurity(mnt_userns, inode, name,
326 &buffer, false);
327 goto out_noalloc;
328 }
329
330 len = security_inode_getsecurity(mnt_userns, inode, name, &buffer,
331 true);
332 if (len < 0)
333 return len;
334 if (size < len) {
335 len = -ERANGE;
336 goto out;
337 }
338 memcpy(value, buffer, len);
339out:
340 kfree(buffer);
341out_noalloc:
342 return len;
343}
344
345
346
347
348
349
350
351
352
353ssize_t
354vfs_getxattr_alloc(struct user_namespace *mnt_userns, struct dentry *dentry,
355 const char *name, char **xattr_value, size_t xattr_size,
356 gfp_t flags)
357{
358 const struct xattr_handler *handler;
359 struct inode *inode = dentry->d_inode;
360 char *value = *xattr_value;
361 int error;
362
363 error = xattr_permission(mnt_userns, inode, name, MAY_READ);
364 if (error)
365 return error;
366
367 handler = xattr_resolve_name(inode, &name);
368 if (IS_ERR(handler))
369 return PTR_ERR(handler);
370 if (!handler->get)
371 return -EOPNOTSUPP;
372 error = handler->get(handler, dentry, inode, name, NULL, 0);
373 if (error < 0)
374 return error;
375
376 if (!value || (error > xattr_size)) {
377 value = krealloc(*xattr_value, error + 1, flags);
378 if (!value)
379 return -ENOMEM;
380 memset(value, 0, error + 1);
381 }
382
383 error = handler->get(handler, dentry, inode, name, value, error);
384 *xattr_value = value;
385 return error;
386}
387
388ssize_t
389__vfs_getxattr(struct dentry *dentry, struct inode *inode, const char *name,
390 void *value, size_t size)
391{
392 const struct xattr_handler *handler;
393
394 handler = xattr_resolve_name(inode, &name);
395 if (IS_ERR(handler))
396 return PTR_ERR(handler);
397 if (!handler->get)
398 return -EOPNOTSUPP;
399 return handler->get(handler, dentry, inode, name, value, size);
400}
401EXPORT_SYMBOL(__vfs_getxattr);
402
403ssize_t
404vfs_getxattr(struct user_namespace *mnt_userns, struct dentry *dentry,
405 const char *name, void *value, size_t size)
406{
407 struct inode *inode = dentry->d_inode;
408 int error;
409
410 error = xattr_permission(mnt_userns, inode, name, MAY_READ);
411 if (error)
412 return error;
413
414 error = security_inode_getxattr(dentry, name);
415 if (error)
416 return error;
417
418 if (!strncmp(name, XATTR_SECURITY_PREFIX,
419 XATTR_SECURITY_PREFIX_LEN)) {
420 const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
421 int ret = xattr_getsecurity(mnt_userns, inode, suffix, value,
422 size);
423
424
425
426
427 if (ret == -EOPNOTSUPP)
428 goto nolsm;
429 return ret;
430 }
431nolsm:
432 return __vfs_getxattr(dentry, inode, name, value, size);
433}
434EXPORT_SYMBOL_GPL(vfs_getxattr);
435
436ssize_t
437vfs_listxattr(struct dentry *dentry, char *list, size_t size)
438{
439 struct inode *inode = d_inode(dentry);
440 ssize_t error;
441
442 error = security_inode_listxattr(dentry);
443 if (error)
444 return error;
445 if (inode->i_op->listxattr && (inode->i_opflags & IOP_XATTR)) {
446 error = inode->i_op->listxattr(dentry, list, size);
447 } else {
448 error = security_inode_listsecurity(inode, list, size);
449 if (size && error > size)
450 error = -ERANGE;
451 }
452 return error;
453}
454EXPORT_SYMBOL_GPL(vfs_listxattr);
455
456int
457__vfs_removexattr(struct user_namespace *mnt_userns, struct dentry *dentry,
458 const char *name)
459{
460 struct inode *inode = d_inode(dentry);
461 const struct xattr_handler *handler;
462
463 handler = xattr_resolve_name(inode, &name);
464 if (IS_ERR(handler))
465 return PTR_ERR(handler);
466 if (!handler->set)
467 return -EOPNOTSUPP;
468 return handler->set(handler, mnt_userns, dentry, inode, name, NULL, 0,
469 XATTR_REPLACE);
470}
471EXPORT_SYMBOL(__vfs_removexattr);
472
473
474
475
476
477
478
479
480
481
482
483int
484__vfs_removexattr_locked(struct user_namespace *mnt_userns,
485 struct dentry *dentry, const char *name,
486 struct inode **delegated_inode)
487{
488 struct inode *inode = dentry->d_inode;
489 int error;
490
491 error = xattr_permission(mnt_userns, inode, name, MAY_WRITE);
492 if (error)
493 return error;
494
495 error = security_inode_removexattr(mnt_userns, dentry, name);
496 if (error)
497 goto out;
498
499 error = try_break_deleg(inode, delegated_inode);
500 if (error)
501 goto out;
502
503 error = __vfs_removexattr(mnt_userns, dentry, name);
504
505 if (!error) {
506 fsnotify_xattr(dentry);
507 evm_inode_post_removexattr(dentry, name);
508 }
509
510out:
511 return error;
512}
513EXPORT_SYMBOL_GPL(__vfs_removexattr_locked);
514
515int
516vfs_removexattr(struct user_namespace *mnt_userns, struct dentry *dentry,
517 const char *name)
518{
519 struct inode *inode = dentry->d_inode;
520 struct inode *delegated_inode = NULL;
521 int error;
522
523retry_deleg:
524 inode_lock(inode);
525 error = __vfs_removexattr_locked(mnt_userns, dentry,
526 name, &delegated_inode);
527 inode_unlock(inode);
528
529 if (delegated_inode) {
530 error = break_deleg_wait(&delegated_inode);
531 if (!error)
532 goto retry_deleg;
533 }
534
535 return error;
536}
537EXPORT_SYMBOL_GPL(vfs_removexattr);
538
539
540
541
542static long
543setxattr(struct user_namespace *mnt_userns, struct dentry *d,
544 const char __user *name, const void __user *value, size_t size,
545 int flags)
546{
547 int error;
548 void *kvalue = NULL;
549 char kname[XATTR_NAME_MAX + 1];
550
551 if (flags & ~(XATTR_CREATE|XATTR_REPLACE))
552 return -EINVAL;
553
554 error = strncpy_from_user(kname, name, sizeof(kname));
555 if (error == 0 || error == sizeof(kname))
556 error = -ERANGE;
557 if (error < 0)
558 return error;
559
560 if (size) {
561 if (size > XATTR_SIZE_MAX)
562 return -E2BIG;
563 kvalue = kvmalloc(size, GFP_KERNEL);
564 if (!kvalue)
565 return -ENOMEM;
566 if (copy_from_user(kvalue, value, size)) {
567 error = -EFAULT;
568 goto out;
569 }
570 if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
571 (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
572 posix_acl_fix_xattr_from_user(mnt_userns, kvalue, size);
573 }
574
575 error = vfs_setxattr(mnt_userns, d, kname, kvalue, size, flags);
576out:
577 kvfree(kvalue);
578
579 return error;
580}
581
582static int path_setxattr(const char __user *pathname,
583 const char __user *name, const void __user *value,
584 size_t size, int flags, unsigned int lookup_flags)
585{
586 struct path path;
587 int error;
588
589retry:
590 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
591 if (error)
592 return error;
593 error = mnt_want_write(path.mnt);
594 if (!error) {
595 error = setxattr(mnt_user_ns(path.mnt), path.dentry, name,
596 value, size, flags);
597 mnt_drop_write(path.mnt);
598 }
599 path_put(&path);
600 if (retry_estale(error, lookup_flags)) {
601 lookup_flags |= LOOKUP_REVAL;
602 goto retry;
603 }
604 return error;
605}
606
607SYSCALL_DEFINE5(setxattr, const char __user *, pathname,
608 const char __user *, name, const void __user *, value,
609 size_t, size, int, flags)
610{
611 return path_setxattr(pathname, name, value, size, flags, LOOKUP_FOLLOW);
612}
613
614SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname,
615 const char __user *, name, const void __user *, value,
616 size_t, size, int, flags)
617{
618 return path_setxattr(pathname, name, value, size, flags, 0);
619}
620
621SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
622 const void __user *,value, size_t, size, int, flags)
623{
624 struct fd f = fdget(fd);
625 int error = -EBADF;
626
627 if (!f.file)
628 return error;
629 audit_file(f.file);
630 error = mnt_want_write_file(f.file);
631 if (!error) {
632 error = setxattr(file_mnt_user_ns(f.file),
633 f.file->f_path.dentry, name,
634 value, size, flags);
635 mnt_drop_write_file(f.file);
636 }
637 fdput(f);
638 return error;
639}
640
641
642
643
644static ssize_t
645getxattr(struct user_namespace *mnt_userns, struct dentry *d,
646 const char __user *name, void __user *value, size_t size)
647{
648 ssize_t error;
649 void *kvalue = NULL;
650 char kname[XATTR_NAME_MAX + 1];
651
652 error = strncpy_from_user(kname, name, sizeof(kname));
653 if (error == 0 || error == sizeof(kname))
654 error = -ERANGE;
655 if (error < 0)
656 return error;
657
658 if (size) {
659 if (size > XATTR_SIZE_MAX)
660 size = XATTR_SIZE_MAX;
661 kvalue = kvzalloc(size, GFP_KERNEL);
662 if (!kvalue)
663 return -ENOMEM;
664 }
665
666 error = vfs_getxattr(mnt_userns, d, kname, kvalue, size);
667 if (error > 0) {
668 if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
669 (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
670 posix_acl_fix_xattr_to_user(mnt_userns, kvalue, error);
671 if (size && copy_to_user(value, kvalue, error))
672 error = -EFAULT;
673 } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) {
674
675
676 error = -E2BIG;
677 }
678
679 kvfree(kvalue);
680
681 return error;
682}
683
684static ssize_t path_getxattr(const char __user *pathname,
685 const char __user *name, void __user *value,
686 size_t size, unsigned int lookup_flags)
687{
688 struct path path;
689 ssize_t error;
690retry:
691 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
692 if (error)
693 return error;
694 error = getxattr(mnt_user_ns(path.mnt), path.dentry, name, value, size);
695 path_put(&path);
696 if (retry_estale(error, lookup_flags)) {
697 lookup_flags |= LOOKUP_REVAL;
698 goto retry;
699 }
700 return error;
701}
702
703SYSCALL_DEFINE4(getxattr, const char __user *, pathname,
704 const char __user *, name, void __user *, value, size_t, size)
705{
706 return path_getxattr(pathname, name, value, size, LOOKUP_FOLLOW);
707}
708
709SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname,
710 const char __user *, name, void __user *, value, size_t, size)
711{
712 return path_getxattr(pathname, name, value, size, 0);
713}
714
715SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name,
716 void __user *, value, size_t, size)
717{
718 struct fd f = fdget(fd);
719 ssize_t error = -EBADF;
720
721 if (!f.file)
722 return error;
723 audit_file(f.file);
724 error = getxattr(file_mnt_user_ns(f.file), f.file->f_path.dentry,
725 name, value, size);
726 fdput(f);
727 return error;
728}
729
730
731
732
733static ssize_t
734listxattr(struct dentry *d, char __user *list, size_t size)
735{
736 ssize_t error;
737 char *klist = NULL;
738
739 if (size) {
740 if (size > XATTR_LIST_MAX)
741 size = XATTR_LIST_MAX;
742 klist = kvmalloc(size, GFP_KERNEL);
743 if (!klist)
744 return -ENOMEM;
745 }
746
747 error = vfs_listxattr(d, klist, size);
748 if (error > 0) {
749 if (size && copy_to_user(list, klist, error))
750 error = -EFAULT;
751 } else if (error == -ERANGE && size >= XATTR_LIST_MAX) {
752
753
754 error = -E2BIG;
755 }
756
757 kvfree(klist);
758
759 return error;
760}
761
762static ssize_t path_listxattr(const char __user *pathname, char __user *list,
763 size_t size, unsigned int lookup_flags)
764{
765 struct path path;
766 ssize_t error;
767retry:
768 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
769 if (error)
770 return error;
771 error = listxattr(path.dentry, list, size);
772 path_put(&path);
773 if (retry_estale(error, lookup_flags)) {
774 lookup_flags |= LOOKUP_REVAL;
775 goto retry;
776 }
777 return error;
778}
779
780SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list,
781 size_t, size)
782{
783 return path_listxattr(pathname, list, size, LOOKUP_FOLLOW);
784}
785
786SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list,
787 size_t, size)
788{
789 return path_listxattr(pathname, list, size, 0);
790}
791
792SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size)
793{
794 struct fd f = fdget(fd);
795 ssize_t error = -EBADF;
796
797 if (!f.file)
798 return error;
799 audit_file(f.file);
800 error = listxattr(f.file->f_path.dentry, list, size);
801 fdput(f);
802 return error;
803}
804
805
806
807
808static long
809removexattr(struct user_namespace *mnt_userns, struct dentry *d,
810 const char __user *name)
811{
812 int error;
813 char kname[XATTR_NAME_MAX + 1];
814
815 error = strncpy_from_user(kname, name, sizeof(kname));
816 if (error == 0 || error == sizeof(kname))
817 error = -ERANGE;
818 if (error < 0)
819 return error;
820
821 return vfs_removexattr(mnt_userns, d, kname);
822}
823
824static int path_removexattr(const char __user *pathname,
825 const char __user *name, unsigned int lookup_flags)
826{
827 struct path path;
828 int error;
829retry:
830 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
831 if (error)
832 return error;
833 error = mnt_want_write(path.mnt);
834 if (!error) {
835 error = removexattr(mnt_user_ns(path.mnt), path.dentry, name);
836 mnt_drop_write(path.mnt);
837 }
838 path_put(&path);
839 if (retry_estale(error, lookup_flags)) {
840 lookup_flags |= LOOKUP_REVAL;
841 goto retry;
842 }
843 return error;
844}
845
846SYSCALL_DEFINE2(removexattr, const char __user *, pathname,
847 const char __user *, name)
848{
849 return path_removexattr(pathname, name, LOOKUP_FOLLOW);
850}
851
852SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname,
853 const char __user *, name)
854{
855 return path_removexattr(pathname, name, 0);
856}
857
858SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name)
859{
860 struct fd f = fdget(fd);
861 int error = -EBADF;
862
863 if (!f.file)
864 return error;
865 audit_file(f.file);
866 error = mnt_want_write_file(f.file);
867 if (!error) {
868 error = removexattr(file_mnt_user_ns(f.file),
869 f.file->f_path.dentry, name);
870 mnt_drop_write_file(f.file);
871 }
872 fdput(f);
873 return error;
874}
875
876
877
878
879
880ssize_t
881generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
882{
883 const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr;
884 unsigned int size = 0;
885
886 if (!buffer) {
887 for_each_xattr_handler(handlers, handler) {
888 if (!handler->name ||
889 (handler->list && !handler->list(dentry)))
890 continue;
891 size += strlen(handler->name) + 1;
892 }
893 } else {
894 char *buf = buffer;
895 size_t len;
896
897 for_each_xattr_handler(handlers, handler) {
898 if (!handler->name ||
899 (handler->list && !handler->list(dentry)))
900 continue;
901 len = strlen(handler->name);
902 if (len + 1 > buffer_size)
903 return -ERANGE;
904 memcpy(buf, handler->name, len + 1);
905 buf += len + 1;
906 buffer_size -= len + 1;
907 }
908 size = buf - buffer;
909 }
910 return size;
911}
912EXPORT_SYMBOL(generic_listxattr);
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929const char *xattr_full_name(const struct xattr_handler *handler,
930 const char *name)
931{
932 size_t prefix_len = strlen(xattr_prefix(handler));
933
934 return name - prefix_len;
935}
936EXPORT_SYMBOL(xattr_full_name);
937
938
939
940
941struct simple_xattr *simple_xattr_alloc(const void *value, size_t size)
942{
943 struct simple_xattr *new_xattr;
944 size_t len;
945
946
947 len = sizeof(*new_xattr) + size;
948 if (len < sizeof(*new_xattr))
949 return NULL;
950
951 new_xattr = kvmalloc(len, GFP_KERNEL);
952 if (!new_xattr)
953 return NULL;
954
955 new_xattr->size = size;
956 memcpy(new_xattr->value, value, size);
957 return new_xattr;
958}
959
960
961
962
963int simple_xattr_get(struct simple_xattrs *xattrs, const char *name,
964 void *buffer, size_t size)
965{
966 struct simple_xattr *xattr;
967 int ret = -ENODATA;
968
969 spin_lock(&xattrs->lock);
970 list_for_each_entry(xattr, &xattrs->head, list) {
971 if (strcmp(name, xattr->name))
972 continue;
973
974 ret = xattr->size;
975 if (buffer) {
976 if (size < xattr->size)
977 ret = -ERANGE;
978 else
979 memcpy(buffer, xattr->value, xattr->size);
980 }
981 break;
982 }
983 spin_unlock(&xattrs->lock);
984 return ret;
985}
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,
1003 const void *value, size_t size, int flags,
1004 ssize_t *removed_size)
1005{
1006 struct simple_xattr *xattr;
1007 struct simple_xattr *new_xattr = NULL;
1008 int err = 0;
1009
1010 if (removed_size)
1011 *removed_size = -1;
1012
1013
1014 if (value) {
1015 new_xattr = simple_xattr_alloc(value, size);
1016 if (!new_xattr)
1017 return -ENOMEM;
1018
1019 new_xattr->name = kstrdup(name, GFP_KERNEL);
1020 if (!new_xattr->name) {
1021 kvfree(new_xattr);
1022 return -ENOMEM;
1023 }
1024 }
1025
1026 spin_lock(&xattrs->lock);
1027 list_for_each_entry(xattr, &xattrs->head, list) {
1028 if (!strcmp(name, xattr->name)) {
1029 if (flags & XATTR_CREATE) {
1030 xattr = new_xattr;
1031 err = -EEXIST;
1032 } else if (new_xattr) {
1033 list_replace(&xattr->list, &new_xattr->list);
1034 if (removed_size)
1035 *removed_size = xattr->size;
1036 } else {
1037 list_del(&xattr->list);
1038 if (removed_size)
1039 *removed_size = xattr->size;
1040 }
1041 goto out;
1042 }
1043 }
1044 if (flags & XATTR_REPLACE) {
1045 xattr = new_xattr;
1046 err = -ENODATA;
1047 } else {
1048 list_add(&new_xattr->list, &xattrs->head);
1049 xattr = NULL;
1050 }
1051out:
1052 spin_unlock(&xattrs->lock);
1053 if (xattr) {
1054 kfree(xattr->name);
1055 kvfree(xattr);
1056 }
1057 return err;
1058
1059}
1060
1061static bool xattr_is_trusted(const char *name)
1062{
1063 return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN);
1064}
1065
1066static int xattr_list_one(char **buffer, ssize_t *remaining_size,
1067 const char *name)
1068{
1069 size_t len = strlen(name) + 1;
1070 if (*buffer) {
1071 if (*remaining_size < len)
1072 return -ERANGE;
1073 memcpy(*buffer, name, len);
1074 *buffer += len;
1075 }
1076 *remaining_size -= len;
1077 return 0;
1078}
1079
1080
1081
1082
1083ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs,
1084 char *buffer, size_t size)
1085{
1086 bool trusted = capable(CAP_SYS_ADMIN);
1087 struct simple_xattr *xattr;
1088 ssize_t remaining_size = size;
1089 int err = 0;
1090
1091#ifdef CONFIG_FS_POSIX_ACL
1092 if (IS_POSIXACL(inode)) {
1093 if (inode->i_acl) {
1094 err = xattr_list_one(&buffer, &remaining_size,
1095 XATTR_NAME_POSIX_ACL_ACCESS);
1096 if (err)
1097 return err;
1098 }
1099 if (inode->i_default_acl) {
1100 err = xattr_list_one(&buffer, &remaining_size,
1101 XATTR_NAME_POSIX_ACL_DEFAULT);
1102 if (err)
1103 return err;
1104 }
1105 }
1106#endif
1107
1108 spin_lock(&xattrs->lock);
1109 list_for_each_entry(xattr, &xattrs->head, list) {
1110
1111 if (!trusted && xattr_is_trusted(xattr->name))
1112 continue;
1113
1114 err = xattr_list_one(&buffer, &remaining_size, xattr->name);
1115 if (err)
1116 break;
1117 }
1118 spin_unlock(&xattrs->lock);
1119
1120 return err ? err : size - remaining_size;
1121}
1122
1123
1124
1125
1126void simple_xattr_list_add(struct simple_xattrs *xattrs,
1127 struct simple_xattr *new_xattr)
1128{
1129 spin_lock(&xattrs->lock);
1130 list_add(&new_xattr->list, &xattrs->head);
1131 spin_unlock(&xattrs->lock);
1132}
1133