4 Extended attribute handling.
6 Copyright (C) 2001 by Andreas Gruenbacher <a.gruenbacher@computer.org>
7 Copyright (C) 2001 SGI - Silicon Graphics, Inc <linux-xfs@oss.sgi.com>
8 Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
11 #include <linux/slab.h>
12 #include <linux/smp_lock.h>
13 #include <linux/file.h>
14 #include <linux/xattr.h>
15 #include <linux/namei.h>
16 #include <linux/security.h>
17 #include <linux/syscalls.h>
18 #include <linux/module.h>
19 #include <linux/fsnotify.h>
20 #include <asm/uaccess.h>
24 vfs_setxattr(struct dentry
*dentry
, char *name
, void *value
,
25 size_t size
, int flags
)
27 struct inode
*inode
= dentry
->d_inode
;
30 mutex_lock(&inode
->i_mutex
);
31 error
= security_inode_setxattr(dentry
, name
, value
, size
, flags
);
35 if (inode
->i_op
->setxattr
) {
36 error
= inode
->i_op
->setxattr(dentry
, name
, value
, size
, flags
);
38 fsnotify_xattr(dentry
);
39 security_inode_post_setxattr(dentry
, name
, value
,
42 } else if (!strncmp(name
, XATTR_SECURITY_PREFIX
,
43 sizeof XATTR_SECURITY_PREFIX
- 1)) {
44 const char *suffix
= name
+ sizeof XATTR_SECURITY_PREFIX
- 1;
45 error
= security_inode_setsecurity(inode
, suffix
, value
,
48 fsnotify_xattr(dentry
);
51 mutex_unlock(&inode
->i_mutex
);
54 EXPORT_SYMBOL_GPL(vfs_setxattr
);
57 vfs_getxattr(struct dentry
*dentry
, char *name
, void *value
, size_t size
)
59 struct inode
*inode
= dentry
->d_inode
;
62 error
= security_inode_getxattr(dentry
, name
);
66 if (inode
->i_op
->getxattr
)
67 error
= inode
->i_op
->getxattr(dentry
, name
, value
, size
);
71 if (!strncmp(name
, XATTR_SECURITY_PREFIX
,
72 sizeof XATTR_SECURITY_PREFIX
- 1)) {
73 const char *suffix
= name
+ sizeof XATTR_SECURITY_PREFIX
- 1;
74 int ret
= security_inode_getsecurity(inode
, suffix
, value
,
77 * Only overwrite the return value if a security module
80 if (ret
!= -EOPNOTSUPP
)
86 EXPORT_SYMBOL_GPL(vfs_getxattr
);
89 vfs_removexattr(struct dentry
*dentry
, char *name
)
91 struct inode
*inode
= dentry
->d_inode
;
94 if (!inode
->i_op
->removexattr
)
97 error
= security_inode_removexattr(dentry
, name
);
101 mutex_lock(&inode
->i_mutex
);
102 error
= inode
->i_op
->removexattr(dentry
, name
);
103 mutex_unlock(&inode
->i_mutex
);
106 fsnotify_xattr(dentry
);
109 EXPORT_SYMBOL_GPL(vfs_removexattr
);
113 * Extended attribute SET operations
116 setxattr(struct dentry
*d
, char __user
*name
, void __user
*value
,
117 size_t size
, int flags
)
121 char kname
[XATTR_NAME_MAX
+ 1];
123 if (flags
& ~(XATTR_CREATE
|XATTR_REPLACE
))
126 error
= strncpy_from_user(kname
, name
, sizeof(kname
));
127 if (error
== 0 || error
== sizeof(kname
))
133 if (size
> XATTR_SIZE_MAX
)
135 kvalue
= kmalloc(size
, GFP_KERNEL
);
138 if (copy_from_user(kvalue
, value
, size
)) {
144 error
= vfs_setxattr(d
, kname
, kvalue
, size
, flags
);
150 sys_setxattr(char __user
*path
, char __user
*name
, void __user
*value
,
151 size_t size
, int flags
)
156 error
= user_path_walk(path
, &nd
);
159 error
= setxattr(nd
.dentry
, name
, value
, size
, flags
);
165 sys_lsetxattr(char __user
*path
, char __user
*name
, void __user
*value
,
166 size_t size
, int flags
)
171 error
= user_path_walk_link(path
, &nd
);
174 error
= setxattr(nd
.dentry
, name
, value
, size
, flags
);
180 sys_fsetxattr(int fd
, char __user
*name
, void __user
*value
,
181 size_t size
, int flags
)
189 error
= setxattr(f
->f_dentry
, name
, value
, size
, flags
);
195 * Extended attribute GET operations
198 getxattr(struct dentry
*d
, char __user
*name
, void __user
*value
, size_t size
)
202 char kname
[XATTR_NAME_MAX
+ 1];
204 error
= strncpy_from_user(kname
, name
, sizeof(kname
));
205 if (error
== 0 || error
== sizeof(kname
))
211 if (size
> XATTR_SIZE_MAX
)
212 size
= XATTR_SIZE_MAX
;
213 kvalue
= kzalloc(size
, GFP_KERNEL
);
218 error
= vfs_getxattr(d
, kname
, kvalue
, size
);
220 if (size
&& copy_to_user(value
, kvalue
, error
))
222 } else if (error
== -ERANGE
&& size
>= XATTR_SIZE_MAX
) {
223 /* The file system tried to returned a value bigger
224 than XATTR_SIZE_MAX bytes. Not possible. */
232 sys_getxattr(char __user
*path
, char __user
*name
, void __user
*value
,
238 error
= user_path_walk(path
, &nd
);
241 error
= getxattr(nd
.dentry
, name
, value
, size
);
247 sys_lgetxattr(char __user
*path
, char __user
*name
, void __user
*value
,
253 error
= user_path_walk_link(path
, &nd
);
256 error
= getxattr(nd
.dentry
, name
, value
, size
);
262 sys_fgetxattr(int fd
, char __user
*name
, void __user
*value
, size_t size
)
265 ssize_t error
= -EBADF
;
270 error
= getxattr(f
->f_dentry
, name
, value
, size
);
276 * Extended attribute LIST operations
279 listxattr(struct dentry
*d
, char __user
*list
, size_t size
)
285 if (size
> XATTR_LIST_MAX
)
286 size
= XATTR_LIST_MAX
;
287 klist
= kmalloc(size
, GFP_KERNEL
);
292 error
= security_inode_listxattr(d
);
296 if (d
->d_inode
->i_op
&& d
->d_inode
->i_op
->listxattr
) {
297 error
= d
->d_inode
->i_op
->listxattr(d
, klist
, size
);
299 error
= security_inode_listsecurity(d
->d_inode
, klist
, size
);
300 if (size
&& error
> size
)
304 if (size
&& copy_to_user(list
, klist
, error
))
306 } else if (error
== -ERANGE
&& size
>= XATTR_LIST_MAX
) {
307 /* The file system tried to returned a list bigger
308 than XATTR_LIST_MAX bytes. Not possible. */
317 sys_listxattr(char __user
*path
, char __user
*list
, size_t size
)
322 error
= user_path_walk(path
, &nd
);
325 error
= listxattr(nd
.dentry
, list
, size
);
331 sys_llistxattr(char __user
*path
, char __user
*list
, size_t size
)
336 error
= user_path_walk_link(path
, &nd
);
339 error
= listxattr(nd
.dentry
, list
, size
);
345 sys_flistxattr(int fd
, char __user
*list
, size_t size
)
348 ssize_t error
= -EBADF
;
353 error
= listxattr(f
->f_dentry
, list
, size
);
359 * Extended attribute REMOVE operations
362 removexattr(struct dentry
*d
, char __user
*name
)
365 char kname
[XATTR_NAME_MAX
+ 1];
367 error
= strncpy_from_user(kname
, name
, sizeof(kname
));
368 if (error
== 0 || error
== sizeof(kname
))
373 return vfs_removexattr(d
, kname
);
377 sys_removexattr(char __user
*path
, char __user
*name
)
382 error
= user_path_walk(path
, &nd
);
385 error
= removexattr(nd
.dentry
, name
);
391 sys_lremovexattr(char __user
*path
, char __user
*name
)
396 error
= user_path_walk_link(path
, &nd
);
399 error
= removexattr(nd
.dentry
, name
);
405 sys_fremovexattr(int fd
, char __user
*name
)
413 error
= removexattr(f
->f_dentry
, name
);
420 strcmp_prefix(const char *a
, const char *a_prefix
)
422 while (*a_prefix
&& *a
== *a_prefix
) {
426 return *a_prefix
? NULL
: a
;
430 * In order to implement different sets of xattr operations for each xattr
431 * prefix with the generic xattr API, a filesystem should create a
432 * null-terminated array of struct xattr_handler (one for each prefix) and
433 * hang a pointer to it off of the s_xattr field of the superblock.
435 * The generic_fooxattr() functions will use this list to dispatch xattr
436 * operations to the correct xattr_handler.
438 #define for_each_xattr_handler(handlers, handler) \
439 for ((handler) = *(handlers)++; \
441 (handler) = *(handlers)++)
444 * Find the xattr_handler with the matching prefix.
446 static struct xattr_handler
*
447 xattr_resolve_name(struct xattr_handler
**handlers
, const char **name
)
449 struct xattr_handler
*handler
;
454 for_each_xattr_handler(handlers
, handler
) {
455 const char *n
= strcmp_prefix(*name
, handler
->prefix
);
465 * Find the handler for the prefix and dispatch its get() operation.
468 generic_getxattr(struct dentry
*dentry
, const char *name
, void *buffer
, size_t size
)
470 struct xattr_handler
*handler
;
471 struct inode
*inode
= dentry
->d_inode
;
473 handler
= xattr_resolve_name(inode
->i_sb
->s_xattr
, &name
);
476 return handler
->get(inode
, name
, buffer
, size
);
480 * Combine the results of the list() operation from every xattr_handler in the
484 generic_listxattr(struct dentry
*dentry
, char *buffer
, size_t buffer_size
)
486 struct inode
*inode
= dentry
->d_inode
;
487 struct xattr_handler
*handler
, **handlers
= inode
->i_sb
->s_xattr
;
488 unsigned int size
= 0;
491 for_each_xattr_handler(handlers
, handler
)
492 size
+= handler
->list(inode
, NULL
, 0, NULL
, 0);
496 for_each_xattr_handler(handlers
, handler
) {
497 size
= handler
->list(inode
, buf
, buffer_size
, NULL
, 0);
498 if (size
> buffer_size
)
509 * Find the handler for the prefix and dispatch its set() operation.
512 generic_setxattr(struct dentry
*dentry
, const char *name
, const void *value
, size_t size
, int flags
)
514 struct xattr_handler
*handler
;
515 struct inode
*inode
= dentry
->d_inode
;
518 value
= ""; /* empty EA, do not remove */
519 handler
= xattr_resolve_name(inode
->i_sb
->s_xattr
, &name
);
522 return handler
->set(inode
, name
, value
, size
, flags
);
526 * Find the handler for the prefix and dispatch its set() operation to remove
527 * any associated extended attribute.
530 generic_removexattr(struct dentry
*dentry
, const char *name
)
532 struct xattr_handler
*handler
;
533 struct inode
*inode
= dentry
->d_inode
;
535 handler
= xattr_resolve_name(inode
->i_sb
->s_xattr
, &name
);
538 return handler
->set(inode
, name
, NULL
, 0, XATTR_REPLACE
);
541 EXPORT_SYMBOL(generic_getxattr
);
542 EXPORT_SYMBOL(generic_listxattr
);
543 EXPORT_SYMBOL(generic_setxattr
);
544 EXPORT_SYMBOL(generic_removexattr
);
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