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 * @mnt_userns: user namespace of the mount of the target inode
246 * @dentry: object to perform setxattr on
247 * @name: xattr name to set
248 * @value: value to set @name to
249 * @size: size of @value
250 * @flags: flags to pass into filesystem operations
251 * @delegated_inode: on return, will contain an inode pointer that
252 * a delegation was broken on, NULL if none.
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
)
259 struct inode
*inode
= dentry
->d_inode
;
262 error
= xattr_permission(mnt_userns
, inode
, name
, MAY_WRITE
);
266 error
= security_inode_setxattr(mnt_userns
, dentry
, name
, value
, size
,
271 error
= try_break_deleg(inode
, delegated_inode
);
275 error
= __vfs_setxattr_noperm(mnt_userns
, dentry
, name
, value
,
281 EXPORT_SYMBOL_GPL(__vfs_setxattr_locked
);
284 vfs_setxattr(struct user_namespace
*mnt_userns
, struct dentry
*dentry
,
285 const char *name
, const void *value
, size_t size
, int flags
)
287 struct inode
*inode
= dentry
->d_inode
;
288 struct inode
*delegated_inode
= NULL
;
289 const void *orig_value
= value
;
292 if (size
&& strcmp(name
, XATTR_NAME_CAPS
) == 0) {
293 error
= cap_convert_nscap(mnt_userns
, dentry
, &value
, size
);
301 error
= __vfs_setxattr_locked(mnt_userns
, dentry
, name
, value
, size
,
302 flags
, &delegated_inode
);
305 if (delegated_inode
) {
306 error
= break_deleg_wait(&delegated_inode
);
310 if (value
!= orig_value
)
315 EXPORT_SYMBOL_GPL(vfs_setxattr
);
318 xattr_getsecurity(struct user_namespace
*mnt_userns
, struct inode
*inode
,
319 const char *name
, void *value
, size_t size
)
324 if (!value
|| !size
) {
325 len
= security_inode_getsecurity(mnt_userns
, inode
, name
,
330 len
= security_inode_getsecurity(mnt_userns
, inode
, name
, &buffer
,
338 memcpy(value
, buffer
, len
);
346 * vfs_getxattr_alloc - allocate memory, if necessary, before calling getxattr
348 * Allocate memory, if not already allocated, or re-allocate correct size,
349 * before retrieving the extended attribute.
351 * Returns the result of alloc, if failed, or the getxattr operation.
354 vfs_getxattr_alloc(struct user_namespace
*mnt_userns
, struct dentry
*dentry
,
355 const char *name
, char **xattr_value
, size_t xattr_size
,
358 const struct xattr_handler
*handler
;
359 struct inode
*inode
= dentry
->d_inode
;
360 char *value
= *xattr_value
;
363 error
= xattr_permission(mnt_userns
, inode
, name
, MAY_READ
);
367 handler
= xattr_resolve_name(inode
, &name
);
369 return PTR_ERR(handler
);
372 error
= handler
->get(handler
, dentry
, inode
, name
, NULL
, 0);
376 if (!value
|| (error
> xattr_size
)) {
377 value
= krealloc(*xattr_value
, error
+ 1, flags
);
380 memset(value
, 0, error
+ 1);
383 error
= handler
->get(handler
, dentry
, inode
, name
, value
, error
);
384 *xattr_value
= value
;
389 __vfs_getxattr(struct dentry
*dentry
, struct inode
*inode
, const char *name
,
390 void *value
, size_t size
)
392 const struct xattr_handler
*handler
;
394 handler
= xattr_resolve_name(inode
, &name
);
396 return PTR_ERR(handler
);
399 return handler
->get(handler
, dentry
, inode
, name
, value
, size
);
401 EXPORT_SYMBOL(__vfs_getxattr
);
404 vfs_getxattr(struct user_namespace
*mnt_userns
, struct dentry
*dentry
,
405 const char *name
, void *value
, size_t size
)
407 struct inode
*inode
= dentry
->d_inode
;
410 error
= xattr_permission(mnt_userns
, inode
, name
, MAY_READ
);
414 error
= security_inode_getxattr(dentry
, name
);
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
,
424 * Only overwrite the return value if a security module
425 * is actually active.
427 if (ret
== -EOPNOTSUPP
)
432 return __vfs_getxattr(dentry
, inode
, name
, value
, size
);
434 EXPORT_SYMBOL_GPL(vfs_getxattr
);
437 vfs_listxattr(struct dentry
*dentry
, char *list
, size_t size
)
439 struct inode
*inode
= d_inode(dentry
);
442 error
= security_inode_listxattr(dentry
);
445 if (inode
->i_op
->listxattr
&& (inode
->i_opflags
& IOP_XATTR
)) {
446 error
= inode
->i_op
->listxattr(dentry
, list
, size
);
448 error
= security_inode_listsecurity(inode
, list
, size
);
449 if (size
&& error
> size
)
454 EXPORT_SYMBOL_GPL(vfs_listxattr
);
457 __vfs_removexattr(struct user_namespace
*mnt_userns
, struct dentry
*dentry
,
460 struct inode
*inode
= d_inode(dentry
);
461 const struct xattr_handler
*handler
;
463 handler
= xattr_resolve_name(inode
, &name
);
465 return PTR_ERR(handler
);
468 return handler
->set(handler
, mnt_userns
, dentry
, inode
, name
, NULL
, 0,
471 EXPORT_SYMBOL(__vfs_removexattr
);
474 * __vfs_removexattr_locked - set an extended attribute while holding the inode
477 * @mnt_userns: user namespace of the mount of the target inode
478 * @dentry: object to perform setxattr on
479 * @name: name of xattr to remove
480 * @delegated_inode: on return, will contain an inode pointer that
481 * a delegation was broken on, NULL if none.
484 __vfs_removexattr_locked(struct user_namespace
*mnt_userns
,
485 struct dentry
*dentry
, const char *name
,
486 struct inode
**delegated_inode
)
488 struct inode
*inode
= dentry
->d_inode
;
491 error
= xattr_permission(mnt_userns
, inode
, name
, MAY_WRITE
);
495 error
= security_inode_removexattr(mnt_userns
, dentry
, name
);
499 error
= try_break_deleg(inode
, delegated_inode
);
503 error
= __vfs_removexattr(mnt_userns
, dentry
, name
);
506 fsnotify_xattr(dentry
);
507 evm_inode_post_removexattr(dentry
, name
);
513 EXPORT_SYMBOL_GPL(__vfs_removexattr_locked
);
516 vfs_removexattr(struct user_namespace
*mnt_userns
, struct dentry
*dentry
,
519 struct inode
*inode
= dentry
->d_inode
;
520 struct inode
*delegated_inode
= NULL
;
525 error
= __vfs_removexattr_locked(mnt_userns
, dentry
,
526 name
, &delegated_inode
);
529 if (delegated_inode
) {
530 error
= break_deleg_wait(&delegated_inode
);
537 EXPORT_SYMBOL_GPL(vfs_removexattr
);
540 * Extended attribute SET operations
543 setxattr(struct user_namespace
*mnt_userns
, struct dentry
*d
,
544 const char __user
*name
, const void __user
*value
, size_t size
,
549 char kname
[XATTR_NAME_MAX
+ 1];
551 if (flags
& ~(XATTR_CREATE
|XATTR_REPLACE
))
554 error
= strncpy_from_user(kname
, name
, sizeof(kname
));
555 if (error
== 0 || error
== sizeof(kname
))
561 if (size
> XATTR_SIZE_MAX
)
563 kvalue
= kvmalloc(size
, GFP_KERNEL
);
566 if (copy_from_user(kvalue
, value
, size
)) {
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
);
575 error
= vfs_setxattr(mnt_userns
, d
, kname
, kvalue
, size
, flags
);
582 static 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
)
590 error
= user_path_at(AT_FDCWD
, pathname
, lookup_flags
, &path
);
593 error
= mnt_want_write(path
.mnt
);
595 error
= setxattr(mnt_user_ns(path
.mnt
), path
.dentry
, name
,
597 mnt_drop_write(path
.mnt
);
600 if (retry_estale(error
, lookup_flags
)) {
601 lookup_flags
|= LOOKUP_REVAL
;
607 SYSCALL_DEFINE5(setxattr
, const char __user
*, pathname
,
608 const char __user
*, name
, const void __user
*, value
,
609 size_t, size
, int, flags
)
611 return path_setxattr(pathname
, name
, value
, size
, flags
, LOOKUP_FOLLOW
);
614 SYSCALL_DEFINE5(lsetxattr
, const char __user
*, pathname
,
615 const char __user
*, name
, const void __user
*, value
,
616 size_t, size
, int, flags
)
618 return path_setxattr(pathname
, name
, value
, size
, flags
, 0);
621 SYSCALL_DEFINE5(fsetxattr
, int, fd
, const char __user
*, name
,
622 const void __user
*,value
, size_t, size
, int, flags
)
624 struct fd f
= fdget(fd
);
630 error
= mnt_want_write_file(f
.file
);
632 error
= setxattr(file_mnt_user_ns(f
.file
),
633 f
.file
->f_path
.dentry
, name
,
635 mnt_drop_write_file(f
.file
);
642 * Extended attribute GET operations
645 getxattr(struct user_namespace
*mnt_userns
, struct dentry
*d
,
646 const char __user
*name
, void __user
*value
, size_t size
)
650 char kname
[XATTR_NAME_MAX
+ 1];
652 error
= strncpy_from_user(kname
, name
, sizeof(kname
));
653 if (error
== 0 || error
== sizeof(kname
))
659 if (size
> XATTR_SIZE_MAX
)
660 size
= XATTR_SIZE_MAX
;
661 kvalue
= kvzalloc(size
, GFP_KERNEL
);
666 error
= vfs_getxattr(mnt_userns
, d
, kname
, kvalue
, size
);
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
))
673 } else if (error
== -ERANGE
&& size
>= XATTR_SIZE_MAX
) {
674 /* The file system tried to returned a value bigger
675 than XATTR_SIZE_MAX bytes. Not possible. */
684 static ssize_t
path_getxattr(const char __user
*pathname
,
685 const char __user
*name
, void __user
*value
,
686 size_t size
, unsigned int lookup_flags
)
691 error
= user_path_at(AT_FDCWD
, pathname
, lookup_flags
, &path
);
694 error
= getxattr(mnt_user_ns(path
.mnt
), path
.dentry
, name
, value
, size
);
696 if (retry_estale(error
, lookup_flags
)) {
697 lookup_flags
|= LOOKUP_REVAL
;
703 SYSCALL_DEFINE4(getxattr
, const char __user
*, pathname
,
704 const char __user
*, name
, void __user
*, value
, size_t, size
)
706 return path_getxattr(pathname
, name
, value
, size
, LOOKUP_FOLLOW
);
709 SYSCALL_DEFINE4(lgetxattr
, const char __user
*, pathname
,
710 const char __user
*, name
, void __user
*, value
, size_t, size
)
712 return path_getxattr(pathname
, name
, value
, size
, 0);
715 SYSCALL_DEFINE4(fgetxattr
, int, fd
, const char __user
*, name
,
716 void __user
*, value
, size_t, size
)
718 struct fd f
= fdget(fd
);
719 ssize_t error
= -EBADF
;
724 error
= getxattr(file_mnt_user_ns(f
.file
), f
.file
->f_path
.dentry
,
731 * Extended attribute LIST operations
734 listxattr(struct dentry
*d
, char __user
*list
, size_t size
)
740 if (size
> XATTR_LIST_MAX
)
741 size
= XATTR_LIST_MAX
;
742 klist
= kvmalloc(size
, GFP_KERNEL
);
747 error
= vfs_listxattr(d
, klist
, size
);
749 if (size
&& copy_to_user(list
, klist
, error
))
751 } else if (error
== -ERANGE
&& size
>= XATTR_LIST_MAX
) {
752 /* The file system tried to returned a list bigger
753 than XATTR_LIST_MAX bytes. Not possible. */
762 static ssize_t
path_listxattr(const char __user
*pathname
, char __user
*list
,
763 size_t size
, unsigned int lookup_flags
)
768 error
= user_path_at(AT_FDCWD
, pathname
, lookup_flags
, &path
);
771 error
= listxattr(path
.dentry
, list
, size
);
773 if (retry_estale(error
, lookup_flags
)) {
774 lookup_flags
|= LOOKUP_REVAL
;
780 SYSCALL_DEFINE3(listxattr
, const char __user
*, pathname
, char __user
*, list
,
783 return path_listxattr(pathname
, list
, size
, LOOKUP_FOLLOW
);
786 SYSCALL_DEFINE3(llistxattr
, const char __user
*, pathname
, char __user
*, list
,
789 return path_listxattr(pathname
, list
, size
, 0);
792 SYSCALL_DEFINE3(flistxattr
, int, fd
, char __user
*, list
, size_t, size
)
794 struct fd f
= fdget(fd
);
795 ssize_t error
= -EBADF
;
800 error
= listxattr(f
.file
->f_path
.dentry
, list
, size
);
806 * Extended attribute REMOVE operations
809 removexattr(struct user_namespace
*mnt_userns
, struct dentry
*d
,
810 const char __user
*name
)
813 char kname
[XATTR_NAME_MAX
+ 1];
815 error
= strncpy_from_user(kname
, name
, sizeof(kname
));
816 if (error
== 0 || error
== sizeof(kname
))
821 return vfs_removexattr(mnt_userns
, d
, kname
);
824 static int path_removexattr(const char __user
*pathname
,
825 const char __user
*name
, unsigned int lookup_flags
)
830 error
= user_path_at(AT_FDCWD
, pathname
, lookup_flags
, &path
);
833 error
= mnt_want_write(path
.mnt
);
835 error
= removexattr(mnt_user_ns(path
.mnt
), path
.dentry
, name
);
836 mnt_drop_write(path
.mnt
);
839 if (retry_estale(error
, lookup_flags
)) {
840 lookup_flags
|= LOOKUP_REVAL
;
846 SYSCALL_DEFINE2(removexattr
, const char __user
*, pathname
,
847 const char __user
*, name
)
849 return path_removexattr(pathname
, name
, LOOKUP_FOLLOW
);
852 SYSCALL_DEFINE2(lremovexattr
, const char __user
*, pathname
,
853 const char __user
*, name
)
855 return path_removexattr(pathname
, name
, 0);
858 SYSCALL_DEFINE2(fremovexattr
, int, fd
, const char __user
*, name
)
860 struct fd f
= fdget(fd
);
866 error
= mnt_want_write_file(f
.file
);
868 error
= removexattr(file_mnt_user_ns(f
.file
),
869 f
.file
->f_path
.dentry
, name
);
870 mnt_drop_write_file(f
.file
);
877 * Combine the results of the list() operation from every xattr_handler in the
881 generic_listxattr(struct dentry
*dentry
, char *buffer
, size_t buffer_size
)
883 const struct xattr_handler
*handler
, **handlers
= dentry
->d_sb
->s_xattr
;
884 unsigned int size
= 0;
887 for_each_xattr_handler(handlers
, handler
) {
888 if (!handler
->name
||
889 (handler
->list
&& !handler
->list(dentry
)))
891 size
+= strlen(handler
->name
) + 1;
897 for_each_xattr_handler(handlers
, handler
) {
898 if (!handler
->name
||
899 (handler
->list
&& !handler
->list(dentry
)))
901 len
= strlen(handler
->name
);
902 if (len
+ 1 > buffer_size
)
904 memcpy(buf
, handler
->name
, len
+ 1);
906 buffer_size
-= len
+ 1;
912 EXPORT_SYMBOL(generic_listxattr
);
915 * xattr_full_name - Compute full attribute name from suffix
917 * @handler: handler of the xattr_handler operation
918 * @name: name passed to the xattr_handler operation
920 * The get and set xattr handler operations are called with the remainder of
921 * the attribute name after skipping the handler's prefix: for example, "foo"
922 * is passed to the get operation of a handler with prefix "user." to get
923 * attribute "user.foo". The full name is still "there" in the name though.
925 * Note: the list xattr handler operation when called from the vfs is passed a
926 * NULL name; some file systems use this operation internally, with varying
929 const char *xattr_full_name(const struct xattr_handler
*handler
,
932 size_t prefix_len
= strlen(xattr_prefix(handler
));
934 return name
- prefix_len
;
936 EXPORT_SYMBOL(xattr_full_name
);
939 * Allocate new xattr and copy in the value; but leave the name to callers.
941 struct simple_xattr
*simple_xattr_alloc(const void *value
, size_t size
)
943 struct simple_xattr
*new_xattr
;
947 len
= sizeof(*new_xattr
) + size
;
948 if (len
< sizeof(*new_xattr
))
951 new_xattr
= kvmalloc(len
, GFP_KERNEL
);
955 new_xattr
->size
= size
;
956 memcpy(new_xattr
->value
, value
, size
);
961 * xattr GET operation for in-memory/pseudo filesystems
963 int simple_xattr_get(struct simple_xattrs
*xattrs
, const char *name
,
964 void *buffer
, size_t size
)
966 struct simple_xattr
*xattr
;
969 spin_lock(&xattrs
->lock
);
970 list_for_each_entry(xattr
, &xattrs
->head
, list
) {
971 if (strcmp(name
, xattr
->name
))
976 if (size
< xattr
->size
)
979 memcpy(buffer
, xattr
->value
, xattr
->size
);
983 spin_unlock(&xattrs
->lock
);
988 * simple_xattr_set - xattr SET operation for in-memory/pseudo filesystems
989 * @xattrs: target simple_xattr list
990 * @name: name of the extended attribute
991 * @value: value of the xattr. If %NULL, will remove the attribute.
992 * @size: size of the new xattr
993 * @flags: %XATTR_{CREATE|REPLACE}
994 * @removed_size: returns size of the removed xattr, -1 if none removed
996 * %XATTR_CREATE is set, the xattr shouldn't exist already; otherwise fails
997 * with -EEXIST. If %XATTR_REPLACE is set, the xattr should exist;
998 * otherwise, fails with -ENODATA.
1000 * Returns 0 on success, -errno on failure.
1002 int simple_xattr_set(struct simple_xattrs
*xattrs
, const char *name
,
1003 const void *value
, size_t size
, int flags
,
1004 ssize_t
*removed_size
)
1006 struct simple_xattr
*xattr
;
1007 struct simple_xattr
*new_xattr
= NULL
;
1013 /* value == NULL means remove */
1015 new_xattr
= simple_xattr_alloc(value
, size
);
1019 new_xattr
->name
= kstrdup(name
, GFP_KERNEL
);
1020 if (!new_xattr
->name
) {
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
) {
1032 } else if (new_xattr
) {
1033 list_replace(&xattr
->list
, &new_xattr
->list
);
1035 *removed_size
= xattr
->size
;
1037 list_del(&xattr
->list
);
1039 *removed_size
= xattr
->size
;
1044 if (flags
& XATTR_REPLACE
) {
1048 list_add(&new_xattr
->list
, &xattrs
->head
);
1052 spin_unlock(&xattrs
->lock
);
1061 static bool xattr_is_trusted(const char *name
)
1063 return !strncmp(name
, XATTR_TRUSTED_PREFIX
, XATTR_TRUSTED_PREFIX_LEN
);
1066 static int xattr_list_one(char **buffer
, ssize_t
*remaining_size
,
1069 size_t len
= strlen(name
) + 1;
1071 if (*remaining_size
< len
)
1073 memcpy(*buffer
, name
, len
);
1076 *remaining_size
-= len
;
1081 * xattr LIST operation for in-memory/pseudo filesystems
1083 ssize_t
simple_xattr_list(struct inode
*inode
, struct simple_xattrs
*xattrs
,
1084 char *buffer
, size_t size
)
1086 bool trusted
= capable(CAP_SYS_ADMIN
);
1087 struct simple_xattr
*xattr
;
1088 ssize_t remaining_size
= size
;
1091 #ifdef CONFIG_FS_POSIX_ACL
1092 if (IS_POSIXACL(inode
)) {
1094 err
= xattr_list_one(&buffer
, &remaining_size
,
1095 XATTR_NAME_POSIX_ACL_ACCESS
);
1099 if (inode
->i_default_acl
) {
1100 err
= xattr_list_one(&buffer
, &remaining_size
,
1101 XATTR_NAME_POSIX_ACL_DEFAULT
);
1108 spin_lock(&xattrs
->lock
);
1109 list_for_each_entry(xattr
, &xattrs
->head
, list
) {
1110 /* skip "trusted." attributes for unprivileged callers */
1111 if (!trusted
&& xattr_is_trusted(xattr
->name
))
1114 err
= xattr_list_one(&buffer
, &remaining_size
, xattr
->name
);
1118 spin_unlock(&xattrs
->lock
);
1120 return err
? err
: size
- remaining_size
;
1124 * Adds an extended attribute to the list
1126 void simple_xattr_list_add(struct simple_xattrs
*xattrs
,
1127 struct simple_xattr
*new_xattr
)
1129 spin_lock(&xattrs
->lock
);
1130 list_add(&new_xattr
->list
, &xattrs
->head
);
1131 spin_unlock(&xattrs
->lock
);