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>
31 strcmp_prefix(const char *a
, const char *a_prefix
)
33 while (*a_prefix
&& *a
== *a_prefix
) {
37 return *a_prefix
? NULL
: a
;
41 * In order to implement different sets of xattr operations for each xattr
42 * prefix, a filesystem should create a null-terminated array of struct
43 * xattr_handler (one for each prefix) and hang a pointer to it off of the
44 * s_xattr field of the superblock.
46 #define for_each_xattr_handler(handlers, handler) \
48 for ((handler) = *(handlers)++; \
50 (handler) = *(handlers)++)
53 * Find the xattr_handler with the matching prefix.
55 static const struct xattr_handler
*
56 xattr_resolve_name(struct inode
*inode
, const char **name
)
58 const struct xattr_handler
**handlers
= inode
->i_sb
->s_xattr
;
59 const struct xattr_handler
*handler
;
61 if (!(inode
->i_opflags
& IOP_XATTR
)) {
62 if (unlikely(is_bad_inode(inode
)))
64 return ERR_PTR(-EOPNOTSUPP
);
66 for_each_xattr_handler(handlers
, handler
) {
69 n
= strcmp_prefix(*name
, xattr_prefix(handler
));
71 if (!handler
->prefix
^ !*n
) {
74 return ERR_PTR(-EINVAL
);
80 return ERR_PTR(-EOPNOTSUPP
);
84 * Check permissions for extended attribute access. This is a bit complicated
85 * because different namespaces have very different rules.
88 xattr_permission(struct user_namespace
*mnt_userns
, struct inode
*inode
,
89 const char *name
, int mask
)
92 * We can never set or remove an extended attribute on a read-only
93 * filesystem or on an immutable / append-only inode.
95 if (mask
& MAY_WRITE
) {
96 if (IS_IMMUTABLE(inode
) || IS_APPEND(inode
))
99 * Updating an xattr will likely cause i_uid and i_gid
100 * to be writen back improperly if their true value is
101 * unknown to the vfs.
103 if (HAS_UNMAPPED_ID(mnt_userns
, inode
))
108 * No restriction for security.* and system.* from the VFS. Decision
109 * on these is left to the underlying filesystem / security module.
111 if (!strncmp(name
, XATTR_SECURITY_PREFIX
, XATTR_SECURITY_PREFIX_LEN
) ||
112 !strncmp(name
, XATTR_SYSTEM_PREFIX
, XATTR_SYSTEM_PREFIX_LEN
))
116 * The trusted.* namespace can only be accessed by privileged users.
118 if (!strncmp(name
, XATTR_TRUSTED_PREFIX
, XATTR_TRUSTED_PREFIX_LEN
)) {
119 if (!capable(CAP_SYS_ADMIN
))
120 return (mask
& MAY_WRITE
) ? -EPERM
: -ENODATA
;
125 * In the user.* namespace, only regular files and directories can have
126 * extended attributes. For sticky directories, only the owner and
127 * privileged users can write attributes.
129 if (!strncmp(name
, XATTR_USER_PREFIX
, XATTR_USER_PREFIX_LEN
)) {
130 if (!S_ISREG(inode
->i_mode
) && !S_ISDIR(inode
->i_mode
))
131 return (mask
& MAY_WRITE
) ? -EPERM
: -ENODATA
;
132 if (S_ISDIR(inode
->i_mode
) && (inode
->i_mode
& S_ISVTX
) &&
133 (mask
& MAY_WRITE
) &&
134 !inode_owner_or_capable(mnt_userns
, inode
))
138 return inode_permission(mnt_userns
, inode
, mask
);
142 * Look for any handler that deals with the specified namespace.
145 xattr_supported_namespace(struct inode
*inode
, const char *prefix
)
147 const struct xattr_handler
**handlers
= inode
->i_sb
->s_xattr
;
148 const struct xattr_handler
*handler
;
151 if (!(inode
->i_opflags
& IOP_XATTR
)) {
152 if (unlikely(is_bad_inode(inode
)))
157 preflen
= strlen(prefix
);
159 for_each_xattr_handler(handlers
, handler
) {
160 if (!strncmp(xattr_prefix(handler
), prefix
, preflen
))
166 EXPORT_SYMBOL(xattr_supported_namespace
);
169 __vfs_setxattr(struct user_namespace
*mnt_userns
, struct dentry
*dentry
,
170 struct inode
*inode
, const char *name
, const void *value
,
171 size_t size
, int flags
)
173 const struct xattr_handler
*handler
;
175 handler
= xattr_resolve_name(inode
, &name
);
177 return PTR_ERR(handler
);
181 value
= ""; /* empty EA, do not remove */
182 return handler
->set(handler
, mnt_userns
, dentry
, inode
, name
, value
,
185 EXPORT_SYMBOL(__vfs_setxattr
);
188 * __vfs_setxattr_noperm - perform setxattr operation without performing
191 * @mnt_userns: user namespace of the mount the inode was found from
192 * @dentry: object to perform setxattr on
193 * @name: xattr name to set
194 * @value: value to set @name to
195 * @size: size of @value
196 * @flags: flags to pass into filesystem operations
198 * returns the result of the internal setxattr or setsecurity operations.
200 * This function requires the caller to lock the inode's i_mutex before it
201 * is executed. It also assumes that the caller will make the appropriate
204 int __vfs_setxattr_noperm(struct user_namespace
*mnt_userns
,
205 struct dentry
*dentry
, const char *name
,
206 const void *value
, size_t size
, int flags
)
208 struct inode
*inode
= dentry
->d_inode
;
210 int issec
= !strncmp(name
, XATTR_SECURITY_PREFIX
,
211 XATTR_SECURITY_PREFIX_LEN
);
214 inode
->i_flags
&= ~S_NOSEC
;
215 if (inode
->i_opflags
& IOP_XATTR
) {
216 error
= __vfs_setxattr(mnt_userns
, dentry
, inode
, name
, value
,
219 fsnotify_xattr(dentry
);
220 security_inode_post_setxattr(dentry
, name
, value
,
224 if (unlikely(is_bad_inode(inode
)))
227 if (error
== -EAGAIN
) {
231 const char *suffix
= name
+ XATTR_SECURITY_PREFIX_LEN
;
233 error
= security_inode_setsecurity(inode
, suffix
, value
,
236 fsnotify_xattr(dentry
);
244 * __vfs_setxattr_locked - set an extended attribute while holding the inode
247 * @mnt_userns: user namespace of the mount of the target inode
248 * @dentry: object to perform setxattr on
249 * @name: xattr name to set
250 * @value: value to set @name to
251 * @size: size of @value
252 * @flags: flags to pass into filesystem operations
253 * @delegated_inode: on return, will contain an inode pointer that
254 * a delegation was broken on, NULL if none.
257 __vfs_setxattr_locked(struct user_namespace
*mnt_userns
, struct dentry
*dentry
,
258 const char *name
, const void *value
, size_t size
,
259 int flags
, struct inode
**delegated_inode
)
261 struct inode
*inode
= dentry
->d_inode
;
264 error
= xattr_permission(mnt_userns
, inode
, name
, MAY_WRITE
);
268 error
= security_inode_setxattr(mnt_userns
, dentry
, name
, value
, size
,
273 error
= try_break_deleg(inode
, delegated_inode
);
277 error
= __vfs_setxattr_noperm(mnt_userns
, dentry
, name
, value
,
283 EXPORT_SYMBOL_GPL(__vfs_setxattr_locked
);
286 vfs_setxattr(struct user_namespace
*mnt_userns
, struct dentry
*dentry
,
287 const char *name
, const void *value
, size_t size
, int flags
)
289 struct inode
*inode
= dentry
->d_inode
;
290 struct inode
*delegated_inode
= NULL
;
291 const void *orig_value
= value
;
294 if (size
&& strcmp(name
, XATTR_NAME_CAPS
) == 0) {
295 error
= cap_convert_nscap(mnt_userns
, dentry
, &value
, size
);
303 error
= __vfs_setxattr_locked(mnt_userns
, dentry
, name
, value
, size
,
304 flags
, &delegated_inode
);
307 if (delegated_inode
) {
308 error
= break_deleg_wait(&delegated_inode
);
312 if (value
!= orig_value
)
317 EXPORT_SYMBOL_GPL(vfs_setxattr
);
320 xattr_getsecurity(struct user_namespace
*mnt_userns
, struct inode
*inode
,
321 const char *name
, void *value
, size_t size
)
326 if (!value
|| !size
) {
327 len
= security_inode_getsecurity(mnt_userns
, inode
, name
,
332 len
= security_inode_getsecurity(mnt_userns
, inode
, name
, &buffer
,
340 memcpy(value
, buffer
, len
);
348 * vfs_getxattr_alloc - allocate memory, if necessary, before calling getxattr
350 * Allocate memory, if not already allocated, or re-allocate correct size,
351 * before retrieving the extended attribute.
353 * Returns the result of alloc, if failed, or the getxattr operation.
356 vfs_getxattr_alloc(struct user_namespace
*mnt_userns
, struct dentry
*dentry
,
357 const char *name
, char **xattr_value
, size_t xattr_size
,
360 const struct xattr_handler
*handler
;
361 struct inode
*inode
= dentry
->d_inode
;
362 char *value
= *xattr_value
;
365 error
= xattr_permission(mnt_userns
, inode
, name
, MAY_READ
);
369 handler
= xattr_resolve_name(inode
, &name
);
371 return PTR_ERR(handler
);
374 error
= handler
->get(handler
, dentry
, inode
, name
, NULL
, 0);
378 if (!value
|| (error
> xattr_size
)) {
379 value
= krealloc(*xattr_value
, error
+ 1, flags
);
382 memset(value
, 0, error
+ 1);
385 error
= handler
->get(handler
, dentry
, inode
, name
, value
, error
);
386 *xattr_value
= value
;
391 __vfs_getxattr(struct dentry
*dentry
, struct inode
*inode
, const char *name
,
392 void *value
, size_t size
)
394 const struct xattr_handler
*handler
;
396 handler
= xattr_resolve_name(inode
, &name
);
398 return PTR_ERR(handler
);
401 return handler
->get(handler
, dentry
, inode
, name
, value
, size
);
403 EXPORT_SYMBOL(__vfs_getxattr
);
406 vfs_getxattr(struct user_namespace
*mnt_userns
, struct dentry
*dentry
,
407 const char *name
, void *value
, size_t size
)
409 struct inode
*inode
= dentry
->d_inode
;
412 error
= xattr_permission(mnt_userns
, inode
, name
, MAY_READ
);
416 error
= security_inode_getxattr(dentry
, name
);
420 if (!strncmp(name
, XATTR_SECURITY_PREFIX
,
421 XATTR_SECURITY_PREFIX_LEN
)) {
422 const char *suffix
= name
+ XATTR_SECURITY_PREFIX_LEN
;
423 int ret
= xattr_getsecurity(mnt_userns
, inode
, suffix
, value
,
426 * Only overwrite the return value if a security module
427 * is actually active.
429 if (ret
== -EOPNOTSUPP
)
434 return __vfs_getxattr(dentry
, inode
, name
, value
, size
);
436 EXPORT_SYMBOL_GPL(vfs_getxattr
);
439 vfs_listxattr(struct dentry
*dentry
, char *list
, size_t size
)
441 struct inode
*inode
= d_inode(dentry
);
444 error
= security_inode_listxattr(dentry
);
447 if (inode
->i_op
->listxattr
&& (inode
->i_opflags
& IOP_XATTR
)) {
448 error
= inode
->i_op
->listxattr(dentry
, list
, size
);
450 error
= security_inode_listsecurity(inode
, list
, size
);
451 if (size
&& error
> size
)
456 EXPORT_SYMBOL_GPL(vfs_listxattr
);
459 __vfs_removexattr(struct user_namespace
*mnt_userns
, struct dentry
*dentry
,
462 struct inode
*inode
= d_inode(dentry
);
463 const struct xattr_handler
*handler
;
465 handler
= xattr_resolve_name(inode
, &name
);
467 return PTR_ERR(handler
);
470 return handler
->set(handler
, mnt_userns
, dentry
, inode
, name
, NULL
, 0,
473 EXPORT_SYMBOL(__vfs_removexattr
);
476 * __vfs_removexattr_locked - set an extended attribute while holding the inode
479 * @mnt_userns: user namespace of the mount of the target inode
480 * @dentry: object to perform setxattr on
481 * @name: name of xattr to remove
482 * @delegated_inode: on return, will contain an inode pointer that
483 * a delegation was broken on, NULL if none.
486 __vfs_removexattr_locked(struct user_namespace
*mnt_userns
,
487 struct dentry
*dentry
, const char *name
,
488 struct inode
**delegated_inode
)
490 struct inode
*inode
= dentry
->d_inode
;
493 error
= xattr_permission(mnt_userns
, inode
, name
, MAY_WRITE
);
497 error
= security_inode_removexattr(mnt_userns
, dentry
, name
);
501 error
= try_break_deleg(inode
, delegated_inode
);
505 error
= __vfs_removexattr(mnt_userns
, dentry
, name
);
508 fsnotify_xattr(dentry
);
509 evm_inode_post_removexattr(dentry
, name
);
515 EXPORT_SYMBOL_GPL(__vfs_removexattr_locked
);
518 vfs_removexattr(struct user_namespace
*mnt_userns
, struct dentry
*dentry
,
521 struct inode
*inode
= dentry
->d_inode
;
522 struct inode
*delegated_inode
= NULL
;
527 error
= __vfs_removexattr_locked(mnt_userns
, dentry
,
528 name
, &delegated_inode
);
531 if (delegated_inode
) {
532 error
= break_deleg_wait(&delegated_inode
);
539 EXPORT_SYMBOL_GPL(vfs_removexattr
);
542 * Extended attribute SET operations
545 int setxattr_copy(const char __user
*name
, struct xattr_ctx
*ctx
)
549 if (ctx
->flags
& ~(XATTR_CREATE
|XATTR_REPLACE
))
552 error
= strncpy_from_user(ctx
->kname
->name
, name
,
553 sizeof(ctx
->kname
->name
));
554 if (error
== 0 || error
== sizeof(ctx
->kname
->name
))
561 if (ctx
->size
> XATTR_SIZE_MAX
)
564 ctx
->kvalue
= vmemdup_user(ctx
->cvalue
, ctx
->size
);
565 if (IS_ERR(ctx
->kvalue
)) {
566 error
= PTR_ERR(ctx
->kvalue
);
574 static void setxattr_convert(struct user_namespace
*mnt_userns
,
575 struct dentry
*d
, struct xattr_ctx
*ctx
)
578 ((strcmp(ctx
->kname
->name
, XATTR_NAME_POSIX_ACL_ACCESS
) == 0) ||
579 (strcmp(ctx
->kname
->name
, XATTR_NAME_POSIX_ACL_DEFAULT
) == 0)))
580 posix_acl_fix_xattr_from_user(mnt_userns
, d_inode(d
),
581 ctx
->kvalue
, ctx
->size
);
584 int do_setxattr(struct user_namespace
*mnt_userns
, struct dentry
*dentry
,
585 struct xattr_ctx
*ctx
)
587 setxattr_convert(mnt_userns
, dentry
, ctx
);
588 return vfs_setxattr(mnt_userns
, dentry
, ctx
->kname
->name
,
589 ctx
->kvalue
, ctx
->size
, ctx
->flags
);
593 setxattr(struct user_namespace
*mnt_userns
, struct dentry
*d
,
594 const char __user
*name
, const void __user
*value
, size_t size
,
597 struct xattr_name kname
;
598 struct xattr_ctx ctx
= {
607 error
= setxattr_copy(name
, &ctx
);
611 error
= do_setxattr(mnt_userns
, d
, &ctx
);
617 static int path_setxattr(const char __user
*pathname
,
618 const char __user
*name
, const void __user
*value
,
619 size_t size
, int flags
, unsigned int lookup_flags
)
625 error
= user_path_at(AT_FDCWD
, pathname
, lookup_flags
, &path
);
628 error
= mnt_want_write(path
.mnt
);
630 error
= setxattr(mnt_user_ns(path
.mnt
), path
.dentry
, name
,
632 mnt_drop_write(path
.mnt
);
635 if (retry_estale(error
, lookup_flags
)) {
636 lookup_flags
|= LOOKUP_REVAL
;
642 SYSCALL_DEFINE5(setxattr
, const char __user
*, pathname
,
643 const char __user
*, name
, const void __user
*, value
,
644 size_t, size
, int, flags
)
646 return path_setxattr(pathname
, name
, value
, size
, flags
, LOOKUP_FOLLOW
);
649 SYSCALL_DEFINE5(lsetxattr
, const char __user
*, pathname
,
650 const char __user
*, name
, const void __user
*, value
,
651 size_t, size
, int, flags
)
653 return path_setxattr(pathname
, name
, value
, size
, flags
, 0);
656 SYSCALL_DEFINE5(fsetxattr
, int, fd
, const char __user
*, name
,
657 const void __user
*,value
, size_t, size
, int, flags
)
659 struct fd f
= fdget(fd
);
665 error
= mnt_want_write_file(f
.file
);
667 error
= setxattr(file_mnt_user_ns(f
.file
),
668 f
.file
->f_path
.dentry
, name
,
670 mnt_drop_write_file(f
.file
);
677 * Extended attribute GET operations
680 do_getxattr(struct user_namespace
*mnt_userns
, struct dentry
*d
,
681 struct xattr_ctx
*ctx
)
684 char *kname
= ctx
->kname
->name
;
687 if (ctx
->size
> XATTR_SIZE_MAX
)
688 ctx
->size
= XATTR_SIZE_MAX
;
689 ctx
->kvalue
= kvzalloc(ctx
->size
, GFP_KERNEL
);
694 error
= vfs_getxattr(mnt_userns
, d
, kname
, ctx
->kvalue
, ctx
->size
);
696 if ((strcmp(kname
, XATTR_NAME_POSIX_ACL_ACCESS
) == 0) ||
697 (strcmp(kname
, XATTR_NAME_POSIX_ACL_DEFAULT
) == 0))
698 posix_acl_fix_xattr_to_user(mnt_userns
, d_inode(d
),
700 if (ctx
->size
&& copy_to_user(ctx
->value
, ctx
->kvalue
, error
))
702 } else if (error
== -ERANGE
&& ctx
->size
>= XATTR_SIZE_MAX
) {
703 /* The file system tried to returned a value bigger
704 than XATTR_SIZE_MAX bytes. Not possible. */
712 getxattr(struct user_namespace
*mnt_userns
, struct dentry
*d
,
713 const char __user
*name
, void __user
*value
, size_t size
)
716 struct xattr_name kname
;
717 struct xattr_ctx ctx
= {
725 error
= strncpy_from_user(kname
.name
, name
, sizeof(kname
.name
));
726 if (error
== 0 || error
== sizeof(kname
.name
))
731 error
= do_getxattr(mnt_userns
, d
, &ctx
);
737 static ssize_t
path_getxattr(const char __user
*pathname
,
738 const char __user
*name
, void __user
*value
,
739 size_t size
, unsigned int lookup_flags
)
744 error
= user_path_at(AT_FDCWD
, pathname
, lookup_flags
, &path
);
747 error
= getxattr(mnt_user_ns(path
.mnt
), path
.dentry
, name
, value
, size
);
749 if (retry_estale(error
, lookup_flags
)) {
750 lookup_flags
|= LOOKUP_REVAL
;
756 SYSCALL_DEFINE4(getxattr
, const char __user
*, pathname
,
757 const char __user
*, name
, void __user
*, value
, size_t, size
)
759 return path_getxattr(pathname
, name
, value
, size
, LOOKUP_FOLLOW
);
762 SYSCALL_DEFINE4(lgetxattr
, const char __user
*, pathname
,
763 const char __user
*, name
, void __user
*, value
, size_t, size
)
765 return path_getxattr(pathname
, name
, value
, size
, 0);
768 SYSCALL_DEFINE4(fgetxattr
, int, fd
, const char __user
*, name
,
769 void __user
*, value
, size_t, size
)
771 struct fd f
= fdget(fd
);
772 ssize_t error
= -EBADF
;
777 error
= getxattr(file_mnt_user_ns(f
.file
), f
.file
->f_path
.dentry
,
784 * Extended attribute LIST operations
787 listxattr(struct dentry
*d
, char __user
*list
, size_t size
)
793 if (size
> XATTR_LIST_MAX
)
794 size
= XATTR_LIST_MAX
;
795 klist
= kvmalloc(size
, GFP_KERNEL
);
800 error
= vfs_listxattr(d
, klist
, size
);
802 if (size
&& copy_to_user(list
, klist
, error
))
804 } else if (error
== -ERANGE
&& size
>= XATTR_LIST_MAX
) {
805 /* The file system tried to returned a list bigger
806 than XATTR_LIST_MAX bytes. Not possible. */
815 static ssize_t
path_listxattr(const char __user
*pathname
, char __user
*list
,
816 size_t size
, unsigned int lookup_flags
)
821 error
= user_path_at(AT_FDCWD
, pathname
, lookup_flags
, &path
);
824 error
= listxattr(path
.dentry
, list
, size
);
826 if (retry_estale(error
, lookup_flags
)) {
827 lookup_flags
|= LOOKUP_REVAL
;
833 SYSCALL_DEFINE3(listxattr
, const char __user
*, pathname
, char __user
*, list
,
836 return path_listxattr(pathname
, list
, size
, LOOKUP_FOLLOW
);
839 SYSCALL_DEFINE3(llistxattr
, const char __user
*, pathname
, char __user
*, list
,
842 return path_listxattr(pathname
, list
, size
, 0);
845 SYSCALL_DEFINE3(flistxattr
, int, fd
, char __user
*, list
, size_t, size
)
847 struct fd f
= fdget(fd
);
848 ssize_t error
= -EBADF
;
853 error
= listxattr(f
.file
->f_path
.dentry
, list
, size
);
859 * Extended attribute REMOVE operations
862 removexattr(struct user_namespace
*mnt_userns
, struct dentry
*d
,
863 const char __user
*name
)
866 char kname
[XATTR_NAME_MAX
+ 1];
868 error
= strncpy_from_user(kname
, name
, sizeof(kname
));
869 if (error
== 0 || error
== sizeof(kname
))
874 return vfs_removexattr(mnt_userns
, d
, kname
);
877 static int path_removexattr(const char __user
*pathname
,
878 const char __user
*name
, unsigned int lookup_flags
)
883 error
= user_path_at(AT_FDCWD
, pathname
, lookup_flags
, &path
);
886 error
= mnt_want_write(path
.mnt
);
888 error
= removexattr(mnt_user_ns(path
.mnt
), path
.dentry
, name
);
889 mnt_drop_write(path
.mnt
);
892 if (retry_estale(error
, lookup_flags
)) {
893 lookup_flags
|= LOOKUP_REVAL
;
899 SYSCALL_DEFINE2(removexattr
, const char __user
*, pathname
,
900 const char __user
*, name
)
902 return path_removexattr(pathname
, name
, LOOKUP_FOLLOW
);
905 SYSCALL_DEFINE2(lremovexattr
, const char __user
*, pathname
,
906 const char __user
*, name
)
908 return path_removexattr(pathname
, name
, 0);
911 SYSCALL_DEFINE2(fremovexattr
, int, fd
, const char __user
*, name
)
913 struct fd f
= fdget(fd
);
919 error
= mnt_want_write_file(f
.file
);
921 error
= removexattr(file_mnt_user_ns(f
.file
),
922 f
.file
->f_path
.dentry
, name
);
923 mnt_drop_write_file(f
.file
);
930 * Combine the results of the list() operation from every xattr_handler in the
934 generic_listxattr(struct dentry
*dentry
, char *buffer
, size_t buffer_size
)
936 const struct xattr_handler
*handler
, **handlers
= dentry
->d_sb
->s_xattr
;
937 unsigned int size
= 0;
940 for_each_xattr_handler(handlers
, handler
) {
941 if (!handler
->name
||
942 (handler
->list
&& !handler
->list(dentry
)))
944 size
+= strlen(handler
->name
) + 1;
950 for_each_xattr_handler(handlers
, handler
) {
951 if (!handler
->name
||
952 (handler
->list
&& !handler
->list(dentry
)))
954 len
= strlen(handler
->name
);
955 if (len
+ 1 > buffer_size
)
957 memcpy(buf
, handler
->name
, len
+ 1);
959 buffer_size
-= len
+ 1;
965 EXPORT_SYMBOL(generic_listxattr
);
968 * xattr_full_name - Compute full attribute name from suffix
970 * @handler: handler of the xattr_handler operation
971 * @name: name passed to the xattr_handler operation
973 * The get and set xattr handler operations are called with the remainder of
974 * the attribute name after skipping the handler's prefix: for example, "foo"
975 * is passed to the get operation of a handler with prefix "user." to get
976 * attribute "user.foo". The full name is still "there" in the name though.
978 * Note: the list xattr handler operation when called from the vfs is passed a
979 * NULL name; some file systems use this operation internally, with varying
982 const char *xattr_full_name(const struct xattr_handler
*handler
,
985 size_t prefix_len
= strlen(xattr_prefix(handler
));
987 return name
- prefix_len
;
989 EXPORT_SYMBOL(xattr_full_name
);
992 * Allocate new xattr and copy in the value; but leave the name to callers.
994 struct simple_xattr
*simple_xattr_alloc(const void *value
, size_t size
)
996 struct simple_xattr
*new_xattr
;
1000 len
= sizeof(*new_xattr
) + size
;
1001 if (len
< sizeof(*new_xattr
))
1004 new_xattr
= kvmalloc(len
, GFP_KERNEL
);
1008 new_xattr
->size
= size
;
1009 memcpy(new_xattr
->value
, value
, size
);
1014 * xattr GET operation for in-memory/pseudo filesystems
1016 int simple_xattr_get(struct simple_xattrs
*xattrs
, const char *name
,
1017 void *buffer
, size_t size
)
1019 struct simple_xattr
*xattr
;
1022 spin_lock(&xattrs
->lock
);
1023 list_for_each_entry(xattr
, &xattrs
->head
, list
) {
1024 if (strcmp(name
, xattr
->name
))
1029 if (size
< xattr
->size
)
1032 memcpy(buffer
, xattr
->value
, xattr
->size
);
1036 spin_unlock(&xattrs
->lock
);
1041 * simple_xattr_set - xattr SET operation for in-memory/pseudo filesystems
1042 * @xattrs: target simple_xattr list
1043 * @name: name of the extended attribute
1044 * @value: value of the xattr. If %NULL, will remove the attribute.
1045 * @size: size of the new xattr
1046 * @flags: %XATTR_{CREATE|REPLACE}
1047 * @removed_size: returns size of the removed xattr, -1 if none removed
1049 * %XATTR_CREATE is set, the xattr shouldn't exist already; otherwise fails
1050 * with -EEXIST. If %XATTR_REPLACE is set, the xattr should exist;
1051 * otherwise, fails with -ENODATA.
1053 * Returns 0 on success, -errno on failure.
1055 int simple_xattr_set(struct simple_xattrs
*xattrs
, const char *name
,
1056 const void *value
, size_t size
, int flags
,
1057 ssize_t
*removed_size
)
1059 struct simple_xattr
*xattr
;
1060 struct simple_xattr
*new_xattr
= NULL
;
1066 /* value == NULL means remove */
1068 new_xattr
= simple_xattr_alloc(value
, size
);
1072 new_xattr
->name
= kstrdup(name
, GFP_KERNEL
);
1073 if (!new_xattr
->name
) {
1079 spin_lock(&xattrs
->lock
);
1080 list_for_each_entry(xattr
, &xattrs
->head
, list
) {
1081 if (!strcmp(name
, xattr
->name
)) {
1082 if (flags
& XATTR_CREATE
) {
1085 } else if (new_xattr
) {
1086 list_replace(&xattr
->list
, &new_xattr
->list
);
1088 *removed_size
= xattr
->size
;
1090 list_del(&xattr
->list
);
1092 *removed_size
= xattr
->size
;
1097 if (flags
& XATTR_REPLACE
) {
1101 list_add(&new_xattr
->list
, &xattrs
->head
);
1105 spin_unlock(&xattrs
->lock
);
1114 static bool xattr_is_trusted(const char *name
)
1116 return !strncmp(name
, XATTR_TRUSTED_PREFIX
, XATTR_TRUSTED_PREFIX_LEN
);
1119 static int xattr_list_one(char **buffer
, ssize_t
*remaining_size
,
1122 size_t len
= strlen(name
) + 1;
1124 if (*remaining_size
< len
)
1126 memcpy(*buffer
, name
, len
);
1129 *remaining_size
-= len
;
1134 * xattr LIST operation for in-memory/pseudo filesystems
1136 ssize_t
simple_xattr_list(struct inode
*inode
, struct simple_xattrs
*xattrs
,
1137 char *buffer
, size_t size
)
1139 bool trusted
= capable(CAP_SYS_ADMIN
);
1140 struct simple_xattr
*xattr
;
1141 ssize_t remaining_size
= size
;
1144 #ifdef CONFIG_FS_POSIX_ACL
1145 if (IS_POSIXACL(inode
)) {
1147 err
= xattr_list_one(&buffer
, &remaining_size
,
1148 XATTR_NAME_POSIX_ACL_ACCESS
);
1152 if (inode
->i_default_acl
) {
1153 err
= xattr_list_one(&buffer
, &remaining_size
,
1154 XATTR_NAME_POSIX_ACL_DEFAULT
);
1161 spin_lock(&xattrs
->lock
);
1162 list_for_each_entry(xattr
, &xattrs
->head
, list
) {
1163 /* skip "trusted." attributes for unprivileged callers */
1164 if (!trusted
&& xattr_is_trusted(xattr
->name
))
1167 err
= xattr_list_one(&buffer
, &remaining_size
, xattr
->name
);
1171 spin_unlock(&xattrs
->lock
);
1173 return err
? err
: size
- remaining_size
;
1177 * Adds an extended attribute to the list
1179 void simple_xattr_list_add(struct simple_xattrs
*xattrs
,
1180 struct simple_xattr
*new_xattr
)
1182 spin_lock(&xattrs
->lock
);
1183 list_add(&new_xattr
->list
, &xattrs
->head
);
1184 spin_unlock(&xattrs
->lock
);