1 // SPDX-License-Identifier: GPL-2.0-only
5 Extended attribute handling.
7 Copyright (C) 2001 by Andreas Gruenbacher <a.gruenbacher@computer.org>
8 Copyright (C) 2001 SGI - Silicon Graphics, Inc <linux-xfs@oss.sgi.com>
9 Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
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>
26 #include <linux/uaccess.h>
29 strcmp_prefix(const char *a
, const char *a_prefix
)
31 while (*a_prefix
&& *a
== *a_prefix
) {
35 return *a_prefix
? NULL
: a
;
39 * In order to implement different sets of xattr operations for each xattr
40 * prefix, a filesystem should create a null-terminated array of struct
41 * xattr_handler (one for each prefix) and hang a pointer to it off of the
42 * s_xattr field of the superblock.
44 #define for_each_xattr_handler(handlers, handler) \
46 for ((handler) = *(handlers)++; \
48 (handler) = *(handlers)++)
51 * Find the xattr_handler with the matching prefix.
53 static const struct xattr_handler
*
54 xattr_resolve_name(struct inode
*inode
, const char **name
)
56 const struct xattr_handler
**handlers
= inode
->i_sb
->s_xattr
;
57 const struct xattr_handler
*handler
;
59 if (!(inode
->i_opflags
& IOP_XATTR
)) {
60 if (unlikely(is_bad_inode(inode
)))
62 return ERR_PTR(-EOPNOTSUPP
);
64 for_each_xattr_handler(handlers
, handler
) {
67 n
= strcmp_prefix(*name
, xattr_prefix(handler
));
69 if (!handler
->prefix
^ !*n
) {
72 return ERR_PTR(-EINVAL
);
78 return ERR_PTR(-EOPNOTSUPP
);
82 * Check permissions for extended attribute access. This is a bit complicated
83 * because different namespaces have very different rules.
86 xattr_permission(struct user_namespace
*mnt_userns
, struct inode
*inode
,
87 const char *name
, int mask
)
90 * We can never set or remove an extended attribute on a read-only
91 * filesystem or on an immutable / append-only inode.
93 if (mask
& MAY_WRITE
) {
94 if (IS_IMMUTABLE(inode
) || IS_APPEND(inode
))
97 * Updating an xattr will likely cause i_uid and i_gid
98 * to be writen back improperly if their true value is
101 if (HAS_UNMAPPED_ID(mnt_userns
, inode
))
106 * No restriction for security.* and system.* from the VFS. Decision
107 * on these is left to the underlying filesystem / security module.
109 if (!strncmp(name
, XATTR_SECURITY_PREFIX
, XATTR_SECURITY_PREFIX_LEN
) ||
110 !strncmp(name
, XATTR_SYSTEM_PREFIX
, XATTR_SYSTEM_PREFIX_LEN
))
114 * The trusted.* namespace can only be accessed by privileged users.
116 if (!strncmp(name
, XATTR_TRUSTED_PREFIX
, XATTR_TRUSTED_PREFIX_LEN
)) {
117 if (!capable(CAP_SYS_ADMIN
))
118 return (mask
& MAY_WRITE
) ? -EPERM
: -ENODATA
;
123 * In the user.* namespace, only regular files and directories can have
124 * extended attributes. For sticky directories, only the owner and
125 * privileged users can write attributes.
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
))
136 return inode_permission(mnt_userns
, inode
, mask
);
140 * Look for any handler that deals with the specified namespace.
143 xattr_supported_namespace(struct inode
*inode
, const char *prefix
)
145 const struct xattr_handler
**handlers
= inode
->i_sb
->s_xattr
;
146 const struct xattr_handler
*handler
;
149 if (!(inode
->i_opflags
& IOP_XATTR
)) {
150 if (unlikely(is_bad_inode(inode
)))
155 preflen
= strlen(prefix
);
157 for_each_xattr_handler(handlers
, handler
) {
158 if (!strncmp(xattr_prefix(handler
), prefix
, preflen
))
164 EXPORT_SYMBOL(xattr_supported_namespace
);
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
)
171 const struct xattr_handler
*handler
;
173 handler
= xattr_resolve_name(inode
, &name
);
175 return PTR_ERR(handler
);
179 value
= ""; /* empty EA, do not remove */
180 return handler
->set(handler
, mnt_userns
, dentry
, inode
, name
, value
,
183 EXPORT_SYMBOL(__vfs_setxattr
);
186 * __vfs_setxattr_noperm - perform setxattr operation without performing
189 * @mnt_userns - user namespace of the mount the inode was found from
190 * @dentry - object to perform setxattr on
191 * @name - xattr name to set
192 * @value - value to set @name to
193 * @size - size of @value
194 * @flags - flags to pass into filesystem operations
196 * returns the result of the internal setxattr or setsecurity operations.
198 * This function requires the caller to lock the inode's i_mutex before it
199 * is executed. It also assumes that the caller will make the appropriate
202 int __vfs_setxattr_noperm(struct user_namespace
*mnt_userns
,
203 struct dentry
*dentry
, const char *name
,
204 const void *value
, size_t size
, int flags
)
206 struct inode
*inode
= dentry
->d_inode
;
208 int issec
= !strncmp(name
, XATTR_SECURITY_PREFIX
,
209 XATTR_SECURITY_PREFIX_LEN
);
212 inode
->i_flags
&= ~S_NOSEC
;
213 if (inode
->i_opflags
& IOP_XATTR
) {
214 error
= __vfs_setxattr(mnt_userns
, dentry
, inode
, name
, value
,
217 fsnotify_xattr(dentry
);
218 security_inode_post_setxattr(dentry
, name
, value
,
222 if (unlikely(is_bad_inode(inode
)))
225 if (error
== -EAGAIN
) {
229 const char *suffix
= name
+ XATTR_SECURITY_PREFIX_LEN
;
231 error
= security_inode_setsecurity(inode
, suffix
, value
,
234 fsnotify_xattr(dentry
);
242 * __vfs_setxattr_locked - set an extended attribute while holding the inode
245 * @dentry: object to perform setxattr on
246 * @name: xattr name to set
247 * @value: value to set @name to
248 * @size: size of @value
249 * @flags: flags to pass into filesystem operations
250 * @delegated_inode: on return, will contain an inode pointer that
251 * a delegation was broken on, NULL if none.
254 __vfs_setxattr_locked(struct user_namespace
*mnt_userns
, struct dentry
*dentry
,
255 const char *name
, const void *value
, size_t size
,
256 int flags
, struct inode
**delegated_inode
)
258 struct inode
*inode
= dentry
->d_inode
;
261 error
= xattr_permission(mnt_userns
, inode
, name
, MAY_WRITE
);
265 error
= security_inode_setxattr(mnt_userns
, dentry
, name
, value
, size
,
270 error
= try_break_deleg(inode
, delegated_inode
);
274 error
= __vfs_setxattr_noperm(mnt_userns
, dentry
, name
, value
,
280 EXPORT_SYMBOL_GPL(__vfs_setxattr_locked
);
283 vfs_setxattr(struct user_namespace
*mnt_userns
, struct dentry
*dentry
,
284 const char *name
, const void *value
, size_t size
, int flags
)
286 struct inode
*inode
= dentry
->d_inode
;
287 struct inode
*delegated_inode
= NULL
;
288 const void *orig_value
= value
;
291 if (size
&& strcmp(name
, XATTR_NAME_CAPS
) == 0) {
292 error
= cap_convert_nscap(mnt_userns
, dentry
, &value
, size
);
300 error
= __vfs_setxattr_locked(mnt_userns
, dentry
, name
, value
, size
,
301 flags
, &delegated_inode
);
304 if (delegated_inode
) {
305 error
= break_deleg_wait(&delegated_inode
);
309 if (value
!= orig_value
)
314 EXPORT_SYMBOL_GPL(vfs_setxattr
);
317 xattr_getsecurity(struct user_namespace
*mnt_userns
, struct inode
*inode
,
318 const char *name
, void *value
, size_t size
)
323 if (!value
|| !size
) {
324 len
= security_inode_getsecurity(mnt_userns
, inode
, name
,
329 len
= security_inode_getsecurity(mnt_userns
, inode
, name
, &buffer
,
337 memcpy(value
, buffer
, len
);
345 * vfs_getxattr_alloc - allocate memory, if necessary, before calling getxattr
347 * Allocate memory, if not already allocated, or re-allocate correct size,
348 * before retrieving the extended attribute.
350 * Returns the result of alloc, if failed, or the getxattr operation.
353 vfs_getxattr_alloc(struct user_namespace
*mnt_userns
, struct dentry
*dentry
,
354 const char *name
, char **xattr_value
, size_t xattr_size
,
357 const struct xattr_handler
*handler
;
358 struct inode
*inode
= dentry
->d_inode
;
359 char *value
= *xattr_value
;
362 error
= xattr_permission(mnt_userns
, inode
, name
, MAY_READ
);
366 handler
= xattr_resolve_name(inode
, &name
);
368 return PTR_ERR(handler
);
371 error
= handler
->get(handler
, dentry
, inode
, name
, NULL
, 0);
375 if (!value
|| (error
> xattr_size
)) {
376 value
= krealloc(*xattr_value
, error
+ 1, flags
);
379 memset(value
, 0, error
+ 1);
382 error
= handler
->get(handler
, dentry
, inode
, name
, value
, error
);
383 *xattr_value
= value
;
388 __vfs_getxattr(struct dentry
*dentry
, struct inode
*inode
, const char *name
,
389 void *value
, size_t size
)
391 const struct xattr_handler
*handler
;
393 handler
= xattr_resolve_name(inode
, &name
);
395 return PTR_ERR(handler
);
398 return handler
->get(handler
, dentry
, inode
, name
, value
, size
);
400 EXPORT_SYMBOL(__vfs_getxattr
);
403 vfs_getxattr(struct user_namespace
*mnt_userns
, struct dentry
*dentry
,
404 const char *name
, void *value
, size_t size
)
406 struct inode
*inode
= dentry
->d_inode
;
409 error
= xattr_permission(mnt_userns
, inode
, name
, MAY_READ
);
413 error
= security_inode_getxattr(dentry
, name
);
417 if (!strncmp(name
, XATTR_SECURITY_PREFIX
,
418 XATTR_SECURITY_PREFIX_LEN
)) {
419 const char *suffix
= name
+ XATTR_SECURITY_PREFIX_LEN
;
420 int ret
= xattr_getsecurity(mnt_userns
, inode
, suffix
, value
,
423 * Only overwrite the return value if a security module
424 * is actually active.
426 if (ret
== -EOPNOTSUPP
)
431 return __vfs_getxattr(dentry
, inode
, name
, value
, size
);
433 EXPORT_SYMBOL_GPL(vfs_getxattr
);
436 vfs_listxattr(struct dentry
*dentry
, char *list
, size_t size
)
438 struct inode
*inode
= d_inode(dentry
);
441 error
= security_inode_listxattr(dentry
);
444 if (inode
->i_op
->listxattr
&& (inode
->i_opflags
& IOP_XATTR
)) {
445 error
= inode
->i_op
->listxattr(dentry
, list
, size
);
447 error
= security_inode_listsecurity(inode
, list
, size
);
448 if (size
&& error
> size
)
453 EXPORT_SYMBOL_GPL(vfs_listxattr
);
456 __vfs_removexattr(struct user_namespace
*mnt_userns
, struct dentry
*dentry
,
459 struct inode
*inode
= d_inode(dentry
);
460 const struct xattr_handler
*handler
;
462 handler
= xattr_resolve_name(inode
, &name
);
464 return PTR_ERR(handler
);
467 return handler
->set(handler
, mnt_userns
, dentry
, inode
, name
, NULL
, 0,
470 EXPORT_SYMBOL(__vfs_removexattr
);
473 * __vfs_removexattr_locked - set an extended attribute while holding the inode
476 * @dentry: object to perform setxattr on
477 * @name: name of xattr to remove
478 * @delegated_inode: on return, will contain an inode pointer that
479 * a delegation was broken on, NULL if none.
482 __vfs_removexattr_locked(struct user_namespace
*mnt_userns
,
483 struct dentry
*dentry
, const char *name
,
484 struct inode
**delegated_inode
)
486 struct inode
*inode
= dentry
->d_inode
;
489 error
= xattr_permission(mnt_userns
, inode
, name
, MAY_WRITE
);
493 error
= security_inode_removexattr(mnt_userns
, dentry
, name
);
497 error
= try_break_deleg(inode
, delegated_inode
);
501 error
= __vfs_removexattr(mnt_userns
, dentry
, name
);
504 fsnotify_xattr(dentry
);
505 evm_inode_post_removexattr(dentry
, name
);
511 EXPORT_SYMBOL_GPL(__vfs_removexattr_locked
);
514 vfs_removexattr(struct user_namespace
*mnt_userns
, struct dentry
*dentry
,
517 struct inode
*inode
= dentry
->d_inode
;
518 struct inode
*delegated_inode
= NULL
;
523 error
= __vfs_removexattr_locked(mnt_userns
, dentry
,
524 name
, &delegated_inode
);
527 if (delegated_inode
) {
528 error
= break_deleg_wait(&delegated_inode
);
535 EXPORT_SYMBOL_GPL(vfs_removexattr
);
538 * Extended attribute SET operations
541 setxattr(struct user_namespace
*mnt_userns
, struct dentry
*d
,
542 const char __user
*name
, const void __user
*value
, size_t size
,
547 char kname
[XATTR_NAME_MAX
+ 1];
549 if (flags
& ~(XATTR_CREATE
|XATTR_REPLACE
))
552 error
= strncpy_from_user(kname
, name
, sizeof(kname
));
553 if (error
== 0 || error
== sizeof(kname
))
559 if (size
> XATTR_SIZE_MAX
)
561 kvalue
= kvmalloc(size
, GFP_KERNEL
);
564 if (copy_from_user(kvalue
, value
, size
)) {
568 if ((strcmp(kname
, XATTR_NAME_POSIX_ACL_ACCESS
) == 0) ||
569 (strcmp(kname
, XATTR_NAME_POSIX_ACL_DEFAULT
) == 0))
570 posix_acl_fix_xattr_from_user(mnt_userns
, kvalue
, size
);
573 error
= vfs_setxattr(mnt_userns
, d
, kname
, kvalue
, size
, flags
);
580 static int path_setxattr(const char __user
*pathname
,
581 const char __user
*name
, const void __user
*value
,
582 size_t size
, int flags
, unsigned int lookup_flags
)
588 error
= user_path_at(AT_FDCWD
, pathname
, lookup_flags
, &path
);
591 error
= mnt_want_write(path
.mnt
);
593 error
= setxattr(mnt_user_ns(path
.mnt
), path
.dentry
, name
,
595 mnt_drop_write(path
.mnt
);
598 if (retry_estale(error
, lookup_flags
)) {
599 lookup_flags
|= LOOKUP_REVAL
;
605 SYSCALL_DEFINE5(setxattr
, const char __user
*, pathname
,
606 const char __user
*, name
, const void __user
*, value
,
607 size_t, size
, int, flags
)
609 return path_setxattr(pathname
, name
, value
, size
, flags
, LOOKUP_FOLLOW
);
612 SYSCALL_DEFINE5(lsetxattr
, const char __user
*, pathname
,
613 const char __user
*, name
, const void __user
*, value
,
614 size_t, size
, int, flags
)
616 return path_setxattr(pathname
, name
, value
, size
, flags
, 0);
619 SYSCALL_DEFINE5(fsetxattr
, int, fd
, const char __user
*, name
,
620 const void __user
*,value
, size_t, size
, int, flags
)
622 struct fd f
= fdget(fd
);
628 error
= mnt_want_write_file(f
.file
);
630 error
= setxattr(file_mnt_user_ns(f
.file
),
631 f
.file
->f_path
.dentry
, name
,
633 mnt_drop_write_file(f
.file
);
640 * Extended attribute GET operations
643 getxattr(struct user_namespace
*mnt_userns
, struct dentry
*d
,
644 const char __user
*name
, void __user
*value
, size_t size
)
648 char kname
[XATTR_NAME_MAX
+ 1];
650 error
= strncpy_from_user(kname
, name
, sizeof(kname
));
651 if (error
== 0 || error
== sizeof(kname
))
657 if (size
> XATTR_SIZE_MAX
)
658 size
= XATTR_SIZE_MAX
;
659 kvalue
= kvzalloc(size
, GFP_KERNEL
);
664 error
= vfs_getxattr(mnt_userns
, d
, kname
, kvalue
, size
);
666 if ((strcmp(kname
, XATTR_NAME_POSIX_ACL_ACCESS
) == 0) ||
667 (strcmp(kname
, XATTR_NAME_POSIX_ACL_DEFAULT
) == 0))
668 posix_acl_fix_xattr_to_user(mnt_userns
, kvalue
, error
);
669 if (size
&& copy_to_user(value
, kvalue
, error
))
671 } else if (error
== -ERANGE
&& size
>= XATTR_SIZE_MAX
) {
672 /* The file system tried to returned a value bigger
673 than XATTR_SIZE_MAX bytes. Not possible. */
682 static ssize_t
path_getxattr(const char __user
*pathname
,
683 const char __user
*name
, void __user
*value
,
684 size_t size
, unsigned int lookup_flags
)
689 error
= user_path_at(AT_FDCWD
, pathname
, lookup_flags
, &path
);
692 error
= getxattr(mnt_user_ns(path
.mnt
), path
.dentry
, name
, value
, size
);
694 if (retry_estale(error
, lookup_flags
)) {
695 lookup_flags
|= LOOKUP_REVAL
;
701 SYSCALL_DEFINE4(getxattr
, const char __user
*, pathname
,
702 const char __user
*, name
, void __user
*, value
, size_t, size
)
704 return path_getxattr(pathname
, name
, value
, size
, LOOKUP_FOLLOW
);
707 SYSCALL_DEFINE4(lgetxattr
, const char __user
*, pathname
,
708 const char __user
*, name
, void __user
*, value
, size_t, size
)
710 return path_getxattr(pathname
, name
, value
, size
, 0);
713 SYSCALL_DEFINE4(fgetxattr
, int, fd
, const char __user
*, name
,
714 void __user
*, value
, size_t, size
)
716 struct fd f
= fdget(fd
);
717 ssize_t error
= -EBADF
;
722 error
= getxattr(file_mnt_user_ns(f
.file
), f
.file
->f_path
.dentry
,
729 * Extended attribute LIST operations
732 listxattr(struct dentry
*d
, char __user
*list
, size_t size
)
738 if (size
> XATTR_LIST_MAX
)
739 size
= XATTR_LIST_MAX
;
740 klist
= kvmalloc(size
, GFP_KERNEL
);
745 error
= vfs_listxattr(d
, klist
, size
);
747 if (size
&& copy_to_user(list
, klist
, error
))
749 } else if (error
== -ERANGE
&& size
>= XATTR_LIST_MAX
) {
750 /* The file system tried to returned a list bigger
751 than XATTR_LIST_MAX bytes. Not possible. */
760 static ssize_t
path_listxattr(const char __user
*pathname
, char __user
*list
,
761 size_t size
, unsigned int lookup_flags
)
766 error
= user_path_at(AT_FDCWD
, pathname
, lookup_flags
, &path
);
769 error
= listxattr(path
.dentry
, list
, size
);
771 if (retry_estale(error
, lookup_flags
)) {
772 lookup_flags
|= LOOKUP_REVAL
;
778 SYSCALL_DEFINE3(listxattr
, const char __user
*, pathname
, char __user
*, list
,
781 return path_listxattr(pathname
, list
, size
, LOOKUP_FOLLOW
);
784 SYSCALL_DEFINE3(llistxattr
, const char __user
*, pathname
, char __user
*, list
,
787 return path_listxattr(pathname
, list
, size
, 0);
790 SYSCALL_DEFINE3(flistxattr
, int, fd
, char __user
*, list
, size_t, size
)
792 struct fd f
= fdget(fd
);
793 ssize_t error
= -EBADF
;
798 error
= listxattr(f
.file
->f_path
.dentry
, list
, size
);
804 * Extended attribute REMOVE operations
807 removexattr(struct user_namespace
*mnt_userns
, struct dentry
*d
,
808 const char __user
*name
)
811 char kname
[XATTR_NAME_MAX
+ 1];
813 error
= strncpy_from_user(kname
, name
, sizeof(kname
));
814 if (error
== 0 || error
== sizeof(kname
))
819 return vfs_removexattr(mnt_userns
, d
, kname
);
822 static int path_removexattr(const char __user
*pathname
,
823 const char __user
*name
, unsigned int lookup_flags
)
828 error
= user_path_at(AT_FDCWD
, pathname
, lookup_flags
, &path
);
831 error
= mnt_want_write(path
.mnt
);
833 error
= removexattr(mnt_user_ns(path
.mnt
), path
.dentry
, name
);
834 mnt_drop_write(path
.mnt
);
837 if (retry_estale(error
, lookup_flags
)) {
838 lookup_flags
|= LOOKUP_REVAL
;
844 SYSCALL_DEFINE2(removexattr
, const char __user
*, pathname
,
845 const char __user
*, name
)
847 return path_removexattr(pathname
, name
, LOOKUP_FOLLOW
);
850 SYSCALL_DEFINE2(lremovexattr
, const char __user
*, pathname
,
851 const char __user
*, name
)
853 return path_removexattr(pathname
, name
, 0);
856 SYSCALL_DEFINE2(fremovexattr
, int, fd
, const char __user
*, name
)
858 struct fd f
= fdget(fd
);
864 error
= mnt_want_write_file(f
.file
);
866 error
= removexattr(file_mnt_user_ns(f
.file
),
867 f
.file
->f_path
.dentry
, name
);
868 mnt_drop_write_file(f
.file
);
875 * Combine the results of the list() operation from every xattr_handler in the
879 generic_listxattr(struct dentry
*dentry
, char *buffer
, size_t buffer_size
)
881 const struct xattr_handler
*handler
, **handlers
= dentry
->d_sb
->s_xattr
;
882 unsigned int size
= 0;
885 for_each_xattr_handler(handlers
, handler
) {
886 if (!handler
->name
||
887 (handler
->list
&& !handler
->list(dentry
)))
889 size
+= strlen(handler
->name
) + 1;
895 for_each_xattr_handler(handlers
, handler
) {
896 if (!handler
->name
||
897 (handler
->list
&& !handler
->list(dentry
)))
899 len
= strlen(handler
->name
);
900 if (len
+ 1 > buffer_size
)
902 memcpy(buf
, handler
->name
, len
+ 1);
904 buffer_size
-= len
+ 1;
910 EXPORT_SYMBOL(generic_listxattr
);
913 * xattr_full_name - Compute full attribute name from suffix
915 * @handler: handler of the xattr_handler operation
916 * @name: name passed to the xattr_handler operation
918 * The get and set xattr handler operations are called with the remainder of
919 * the attribute name after skipping the handler's prefix: for example, "foo"
920 * is passed to the get operation of a handler with prefix "user." to get
921 * attribute "user.foo". The full name is still "there" in the name though.
923 * Note: the list xattr handler operation when called from the vfs is passed a
924 * NULL name; some file systems use this operation internally, with varying
927 const char *xattr_full_name(const struct xattr_handler
*handler
,
930 size_t prefix_len
= strlen(xattr_prefix(handler
));
932 return name
- prefix_len
;
934 EXPORT_SYMBOL(xattr_full_name
);
937 * Allocate new xattr and copy in the value; but leave the name to callers.
939 struct simple_xattr
*simple_xattr_alloc(const void *value
, size_t size
)
941 struct simple_xattr
*new_xattr
;
945 len
= sizeof(*new_xattr
) + size
;
946 if (len
< sizeof(*new_xattr
))
949 new_xattr
= kvmalloc(len
, GFP_KERNEL
);
953 new_xattr
->size
= size
;
954 memcpy(new_xattr
->value
, value
, size
);
959 * xattr GET operation for in-memory/pseudo filesystems
961 int simple_xattr_get(struct simple_xattrs
*xattrs
, const char *name
,
962 void *buffer
, size_t size
)
964 struct simple_xattr
*xattr
;
967 spin_lock(&xattrs
->lock
);
968 list_for_each_entry(xattr
, &xattrs
->head
, list
) {
969 if (strcmp(name
, xattr
->name
))
974 if (size
< xattr
->size
)
977 memcpy(buffer
, xattr
->value
, xattr
->size
);
981 spin_unlock(&xattrs
->lock
);
986 * simple_xattr_set - xattr SET operation for in-memory/pseudo filesystems
987 * @xattrs: target simple_xattr list
988 * @name: name of the extended attribute
989 * @value: value of the xattr. If %NULL, will remove the attribute.
990 * @size: size of the new xattr
991 * @flags: %XATTR_{CREATE|REPLACE}
992 * @removed_size: returns size of the removed xattr, -1 if none removed
994 * %XATTR_CREATE is set, the xattr shouldn't exist already; otherwise fails
995 * with -EEXIST. If %XATTR_REPLACE is set, the xattr should exist;
996 * otherwise, fails with -ENODATA.
998 * Returns 0 on success, -errno on failure.
1000 int simple_xattr_set(struct simple_xattrs
*xattrs
, const char *name
,
1001 const void *value
, size_t size
, int flags
,
1002 ssize_t
*removed_size
)
1004 struct simple_xattr
*xattr
;
1005 struct simple_xattr
*new_xattr
= NULL
;
1011 /* value == NULL means remove */
1013 new_xattr
= simple_xattr_alloc(value
, size
);
1017 new_xattr
->name
= kstrdup(name
, GFP_KERNEL
);
1018 if (!new_xattr
->name
) {
1024 spin_lock(&xattrs
->lock
);
1025 list_for_each_entry(xattr
, &xattrs
->head
, list
) {
1026 if (!strcmp(name
, xattr
->name
)) {
1027 if (flags
& XATTR_CREATE
) {
1030 } else if (new_xattr
) {
1031 list_replace(&xattr
->list
, &new_xattr
->list
);
1033 *removed_size
= xattr
->size
;
1035 list_del(&xattr
->list
);
1037 *removed_size
= xattr
->size
;
1042 if (flags
& XATTR_REPLACE
) {
1046 list_add(&new_xattr
->list
, &xattrs
->head
);
1050 spin_unlock(&xattrs
->lock
);
1059 static bool xattr_is_trusted(const char *name
)
1061 return !strncmp(name
, XATTR_TRUSTED_PREFIX
, XATTR_TRUSTED_PREFIX_LEN
);
1064 static int xattr_list_one(char **buffer
, ssize_t
*remaining_size
,
1067 size_t len
= strlen(name
) + 1;
1069 if (*remaining_size
< len
)
1071 memcpy(*buffer
, name
, len
);
1074 *remaining_size
-= len
;
1079 * xattr LIST operation for in-memory/pseudo filesystems
1081 ssize_t
simple_xattr_list(struct inode
*inode
, struct simple_xattrs
*xattrs
,
1082 char *buffer
, size_t size
)
1084 bool trusted
= capable(CAP_SYS_ADMIN
);
1085 struct simple_xattr
*xattr
;
1086 ssize_t remaining_size
= size
;
1089 #ifdef CONFIG_FS_POSIX_ACL
1090 if (IS_POSIXACL(inode
)) {
1092 err
= xattr_list_one(&buffer
, &remaining_size
,
1093 XATTR_NAME_POSIX_ACL_ACCESS
);
1097 if (inode
->i_default_acl
) {
1098 err
= xattr_list_one(&buffer
, &remaining_size
,
1099 XATTR_NAME_POSIX_ACL_DEFAULT
);
1106 spin_lock(&xattrs
->lock
);
1107 list_for_each_entry(xattr
, &xattrs
->head
, list
) {
1108 /* skip "trusted." attributes for unprivileged callers */
1109 if (!trusted
&& xattr_is_trusted(xattr
->name
))
1112 err
= xattr_list_one(&buffer
, &remaining_size
, xattr
->name
);
1116 spin_unlock(&xattrs
->lock
);
1118 return err
? err
: size
- remaining_size
;
1122 * Adds an extended attribute to the list
1124 void simple_xattr_list_add(struct simple_xattrs
*xattrs
,
1125 struct simple_xattr
*new_xattr
)
1127 spin_lock(&xattrs
->lock
);
1128 list_add(&new_xattr
->list
, &xattrs
->head
);
1129 spin_unlock(&xattrs
->lock
);