blob: c69e6d43a0d2e863c3e2d6680731371e0d7ef284 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 File: fs/xattr.c
3
4 Extended attribute handling.
5
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>
9 */
10#include <linux/fs.h>
11#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/file.h>
13#include <linux/xattr.h>
Dave Hansen18f335a2008-02-15 14:37:38 -080014#include <linux/mount.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/namei.h>
16#include <linux/security.h>
Mimi Zoharc7b87de2011-03-09 14:39:18 -050017#include <linux/evm.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018#include <linux/syscalls.h>
Paul Gortmaker630d9c42011-11-16 23:57:37 -050019#include <linux/export.h>
Robert Love0eeca282005-07-12 17:06:03 -040020#include <linux/fsnotify.h>
Amy Griffis73241cc2005-11-03 16:00:25 +000021#include <linux/audit.h>
Andrew Morton0d08d7b2012-04-05 14:25:07 -070022#include <linux/vmalloc.h>
Eric W. Biederman2f6f0652012-02-07 18:52:57 -080023#include <linux/posix_acl_xattr.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070024
Andrew Morton0d08d7b2012-04-05 14:25:07 -070025#include <asm/uaccess.h>
Christoph Hellwig5be196e2006-01-09 20:51:55 -080026
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -080027/*
28 * Check permissions for extended attribute access. This is a bit complicated
29 * because different namespaces have very different rules.
30 */
31static int
32xattr_permission(struct inode *inode, const char *name, int mask)
33{
34 /*
35 * We can never set or remove an extended attribute on a read-only
36 * filesystem or on an immutable / append-only inode.
37 */
38 if (mask & MAY_WRITE) {
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -080039 if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
40 return -EPERM;
41 }
42
43 /*
44 * No restriction for security.* and system.* from the VFS. Decision
45 * on these is left to the underlying filesystem / security module.
46 */
47 if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) ||
48 !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
49 return 0;
50
51 /*
Andreas Gruenbacher55b23bd2011-05-27 14:50:36 +020052 * The trusted.* namespace can only be accessed by privileged users.
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -080053 */
Andreas Gruenbacher55b23bd2011-05-27 14:50:36 +020054 if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) {
55 if (!capable(CAP_SYS_ADMIN))
56 return (mask & MAY_WRITE) ? -EPERM : -ENODATA;
57 return 0;
58 }
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -080059
Andreas Gruenbacher55b23bd2011-05-27 14:50:36 +020060 /*
61 * In the user.* namespace, only regular files and directories can have
Andreas Gruenbacherf1f2d872006-11-02 22:07:29 -080062 * extended attributes. For sticky directories, only the owner and
Andreas Gruenbacher55b23bd2011-05-27 14:50:36 +020063 * privileged users can write attributes.
Andreas Gruenbacherf1f2d872006-11-02 22:07:29 -080064 */
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -080065 if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) {
Andreas Gruenbacherf1f2d872006-11-02 22:07:29 -080066 if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
Andreas Gruenbacher55b23bd2011-05-27 14:50:36 +020067 return (mask & MAY_WRITE) ? -EPERM : -ENODATA;
Andreas Gruenbacherf1f2d872006-11-02 22:07:29 -080068 if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) &&
Serge E. Hallyn2e149672011-03-23 16:43:26 -070069 (mask & MAY_WRITE) && !inode_owner_or_capable(inode))
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -080070 return -EPERM;
71 }
72
Al Virof419a2e2008-07-22 00:07:17 -040073 return inode_permission(inode, mask);
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -080074}
75
David P. Quigleyb1ab7e42009-09-03 14:25:56 -040076/**
77 * __vfs_setxattr_noperm - perform setxattr operation without performing
78 * permission checks.
79 *
80 * @dentry - object to perform setxattr on
81 * @name - xattr name to set
82 * @value - value to set @name to
83 * @size - size of @value
84 * @flags - flags to pass into filesystem operations
85 *
86 * returns the result of the internal setxattr or setsecurity operations.
87 *
88 * This function requires the caller to lock the inode's i_mutex before it
89 * is executed. It also assumes that the caller will make the appropriate
90 * permission checks.
91 */
92int __vfs_setxattr_noperm(struct dentry *dentry, const char *name,
93 const void *value, size_t size, int flags)
Christoph Hellwig5be196e2006-01-09 20:51:55 -080094{
95 struct inode *inode = dentry->d_inode;
David P. Quigleyb1ab7e42009-09-03 14:25:56 -040096 int error = -EOPNOTSUPP;
Andi Kleen69b45732011-05-28 08:25:51 -070097 int issec = !strncmp(name, XATTR_SECURITY_PREFIX,
98 XATTR_SECURITY_PREFIX_LEN);
Christoph Hellwig5be196e2006-01-09 20:51:55 -080099
Andi Kleen69b45732011-05-28 08:25:51 -0700100 if (issec)
101 inode->i_flags &= ~S_NOSEC;
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800102 if (inode->i_op->setxattr) {
103 error = inode->i_op->setxattr(dentry, name, value, size, flags);
104 if (!error) {
105 fsnotify_xattr(dentry);
106 security_inode_post_setxattr(dentry, name, value,
107 size, flags);
108 }
Andi Kleen69b45732011-05-28 08:25:51 -0700109 } else if (issec) {
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800110 const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800111 error = security_inode_setsecurity(inode, suffix, value,
112 size, flags);
113 if (!error)
114 fsnotify_xattr(dentry);
115 }
David P. Quigleyb1ab7e42009-09-03 14:25:56 -0400116
117 return error;
118}
119
120
121int
122vfs_setxattr(struct dentry *dentry, const char *name, const void *value,
123 size_t size, int flags)
124{
125 struct inode *inode = dentry->d_inode;
126 int error;
127
128 error = xattr_permission(inode, name, MAY_WRITE);
129 if (error)
130 return error;
131
132 mutex_lock(&inode->i_mutex);
133 error = security_inode_setxattr(dentry, name, value, size, flags);
134 if (error)
135 goto out;
136
137 error = __vfs_setxattr_noperm(dentry, name, value, size, flags);
138
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800139out:
140 mutex_unlock(&inode->i_mutex);
141 return error;
142}
143EXPORT_SYMBOL_GPL(vfs_setxattr);
144
145ssize_t
David P. Quigley42492592008-02-04 22:29:39 -0800146xattr_getsecurity(struct inode *inode, const char *name, void *value,
147 size_t size)
148{
149 void *buffer = NULL;
150 ssize_t len;
151
152 if (!value || !size) {
153 len = security_inode_getsecurity(inode, name, &buffer, false);
154 goto out_noalloc;
155 }
156
157 len = security_inode_getsecurity(inode, name, &buffer, true);
158 if (len < 0)
159 return len;
160 if (size < len) {
161 len = -ERANGE;
162 goto out;
163 }
164 memcpy(value, buffer, len);
165out:
166 security_release_secctx(buffer, len);
167out_noalloc:
168 return len;
169}
170EXPORT_SYMBOL_GPL(xattr_getsecurity);
171
Mimi Zohar1601fba2011-03-09 14:23:34 -0500172/*
173 * vfs_getxattr_alloc - allocate memory, if necessary, before calling getxattr
174 *
175 * Allocate memory, if not already allocated, or re-allocate correct size,
176 * before retrieving the extended attribute.
177 *
178 * Returns the result of alloc, if failed, or the getxattr operation.
179 */
180ssize_t
181vfs_getxattr_alloc(struct dentry *dentry, const char *name, char **xattr_value,
182 size_t xattr_size, gfp_t flags)
183{
184 struct inode *inode = dentry->d_inode;
185 char *value = *xattr_value;
186 int error;
187
188 error = xattr_permission(inode, name, MAY_READ);
189 if (error)
190 return error;
191
192 if (!inode->i_op->getxattr)
193 return -EOPNOTSUPP;
194
195 error = inode->i_op->getxattr(dentry, name, NULL, 0);
196 if (error < 0)
197 return error;
198
199 if (!value || (error > xattr_size)) {
200 value = krealloc(*xattr_value, error + 1, flags);
201 if (!value)
202 return -ENOMEM;
203 memset(value, 0, error + 1);
204 }
205
206 error = inode->i_op->getxattr(dentry, name, value, error);
207 *xattr_value = value;
208 return error;
209}
210
211/* Compare an extended attribute value with the given value */
212int vfs_xattr_cmp(struct dentry *dentry, const char *xattr_name,
213 const char *value, size_t size, gfp_t flags)
214{
215 char *xattr_value = NULL;
216 int rc;
217
218 rc = vfs_getxattr_alloc(dentry, xattr_name, &xattr_value, 0, flags);
219 if (rc < 0)
220 return rc;
221
222 if ((rc != size) || (memcmp(xattr_value, value, rc) != 0))
223 rc = -EINVAL;
224 else
225 rc = 0;
226 kfree(xattr_value);
227 return rc;
228}
229
David P. Quigley42492592008-02-04 22:29:39 -0800230ssize_t
David Howells8f0cfa52008-04-29 00:59:41 -0700231vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size)
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800232{
233 struct inode *inode = dentry->d_inode;
234 int error;
235
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800236 error = xattr_permission(inode, name, MAY_READ);
237 if (error)
238 return error;
239
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800240 error = security_inode_getxattr(dentry, name);
241 if (error)
242 return error;
243
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800244 if (!strncmp(name, XATTR_SECURITY_PREFIX,
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800245 XATTR_SECURITY_PREFIX_LEN)) {
246 const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
David P. Quigley42492592008-02-04 22:29:39 -0800247 int ret = xattr_getsecurity(inode, suffix, value, size);
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800248 /*
249 * Only overwrite the return value if a security module
250 * is actually active.
251 */
David P. Quigley4bea5802008-02-04 22:29:40 -0800252 if (ret == -EOPNOTSUPP)
253 goto nolsm;
254 return ret;
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800255 }
David P. Quigley4bea5802008-02-04 22:29:40 -0800256nolsm:
257 if (inode->i_op->getxattr)
258 error = inode->i_op->getxattr(dentry, name, value, size);
259 else
260 error = -EOPNOTSUPP;
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800261
262 return error;
263}
264EXPORT_SYMBOL_GPL(vfs_getxattr);
265
Bill Nottingham659564c2006-10-09 16:10:48 -0400266ssize_t
267vfs_listxattr(struct dentry *d, char *list, size_t size)
268{
269 ssize_t error;
270
271 error = security_inode_listxattr(d);
272 if (error)
273 return error;
274 error = -EOPNOTSUPP;
Al Viroacfa4382008-12-04 10:06:33 -0500275 if (d->d_inode->i_op->listxattr) {
Bill Nottingham659564c2006-10-09 16:10:48 -0400276 error = d->d_inode->i_op->listxattr(d, list, size);
277 } else {
278 error = security_inode_listsecurity(d->d_inode, list, size);
279 if (size && error > size)
280 error = -ERANGE;
281 }
282 return error;
283}
284EXPORT_SYMBOL_GPL(vfs_listxattr);
285
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800286int
David Howells8f0cfa52008-04-29 00:59:41 -0700287vfs_removexattr(struct dentry *dentry, const char *name)
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800288{
289 struct inode *inode = dentry->d_inode;
290 int error;
291
292 if (!inode->i_op->removexattr)
293 return -EOPNOTSUPP;
294
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800295 error = xattr_permission(inode, name, MAY_WRITE);
296 if (error)
297 return error;
298
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800299 mutex_lock(&inode->i_mutex);
Mimi Zohar2ab51f32011-03-23 17:23:06 -0400300 error = security_inode_removexattr(dentry, name);
301 if (error) {
302 mutex_unlock(&inode->i_mutex);
303 return error;
304 }
305
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800306 error = inode->i_op->removexattr(dentry, name);
307 mutex_unlock(&inode->i_mutex);
308
Mimi Zoharc7b87de2011-03-09 14:39:18 -0500309 if (!error) {
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800310 fsnotify_xattr(dentry);
Mimi Zoharc7b87de2011-03-09 14:39:18 -0500311 evm_inode_post_removexattr(dentry, name);
312 }
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800313 return error;
314}
315EXPORT_SYMBOL_GPL(vfs_removexattr);
316
317
Linus Torvalds1da177e2005-04-16 15:20:36 -0700318/*
319 * Extended attribute SET operations
320 */
321static long
David Howells8f0cfa52008-04-29 00:59:41 -0700322setxattr(struct dentry *d, const char __user *name, const void __user *value,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700323 size_t size, int flags)
324{
325 int error;
326 void *kvalue = NULL;
Andrew Morton44c82492012-04-05 14:25:07 -0700327 void *vvalue = NULL; /* If non-NULL, we used vmalloc() */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700328 char kname[XATTR_NAME_MAX + 1];
329
330 if (flags & ~(XATTR_CREATE|XATTR_REPLACE))
331 return -EINVAL;
332
333 error = strncpy_from_user(kname, name, sizeof(kname));
334 if (error == 0 || error == sizeof(kname))
335 error = -ERANGE;
336 if (error < 0)
337 return error;
338
339 if (size) {
340 if (size > XATTR_SIZE_MAX)
341 return -E2BIG;
Andrew Morton44c82492012-04-05 14:25:07 -0700342 kvalue = kmalloc(size, GFP_KERNEL | __GFP_NOWARN);
343 if (!kvalue) {
344 vvalue = vmalloc(size);
345 if (!vvalue)
346 return -ENOMEM;
347 kvalue = vvalue;
348 }
349 if (copy_from_user(kvalue, value, size)) {
350 error = -EFAULT;
351 goto out;
352 }
Eric W. Biederman2f6f0652012-02-07 18:52:57 -0800353 if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
354 (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
355 posix_acl_fix_xattr_from_user(kvalue, size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356 }
357
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800358 error = vfs_setxattr(d, kname, kvalue, size, flags);
Andrew Morton44c82492012-04-05 14:25:07 -0700359out:
360 if (vvalue)
361 vfree(vvalue);
362 else
363 kfree(kvalue);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364 return error;
365}
366
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100367SYSCALL_DEFINE5(setxattr, const char __user *, pathname,
368 const char __user *, name, const void __user *, value,
369 size_t, size, int, flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370{
Al Viro2d8f3032008-07-22 09:59:21 -0400371 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372 int error;
Jeff Layton68f1bb82012-12-11 12:10:15 -0500373 unsigned int lookup_flags = LOOKUP_FOLLOW;
374retry:
375 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700376 if (error)
377 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400378 error = mnt_want_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800379 if (!error) {
Al Viro2d8f3032008-07-22 09:59:21 -0400380 error = setxattr(path.dentry, name, value, size, flags);
381 mnt_drop_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800382 }
Al Viro2d8f3032008-07-22 09:59:21 -0400383 path_put(&path);
Jeff Layton68f1bb82012-12-11 12:10:15 -0500384 if (retry_estale(error, lookup_flags)) {
385 lookup_flags |= LOOKUP_REVAL;
386 goto retry;
387 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388 return error;
389}
390
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100391SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname,
392 const char __user *, name, const void __user *, value,
393 size_t, size, int, flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700394{
Al Viro2d8f3032008-07-22 09:59:21 -0400395 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396 int error;
Jeff Layton49e09e12012-12-11 12:10:15 -0500397 unsigned int lookup_flags = 0;
398retry:
399 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400 if (error)
401 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400402 error = mnt_want_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800403 if (!error) {
Al Viro2d8f3032008-07-22 09:59:21 -0400404 error = setxattr(path.dentry, name, value, size, flags);
405 mnt_drop_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800406 }
Al Viro2d8f3032008-07-22 09:59:21 -0400407 path_put(&path);
Jeff Layton49e09e12012-12-11 12:10:15 -0500408 if (retry_estale(error, lookup_flags)) {
409 lookup_flags |= LOOKUP_REVAL;
410 goto retry;
411 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412 return error;
413}
414
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100415SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
416 const void __user *,value, size_t, size, int, flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700417{
Al Viro2903ff02012-08-28 12:52:22 -0400418 struct fd f = fdget(fd);
Amy Griffis73241cc2005-11-03 16:00:25 +0000419 struct dentry *dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420 int error = -EBADF;
421
Al Viro2903ff02012-08-28 12:52:22 -0400422 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700423 return error;
Al Viro2903ff02012-08-28 12:52:22 -0400424 dentry = f.file->f_path.dentry;
Jeff Laytonbfcec702012-10-10 15:25:23 -0400425 audit_inode(NULL, dentry, 0);
Al Viro2903ff02012-08-28 12:52:22 -0400426 error = mnt_want_write_file(f.file);
Dave Hansen18f335a2008-02-15 14:37:38 -0800427 if (!error) {
428 error = setxattr(dentry, name, value, size, flags);
Al Viro2903ff02012-08-28 12:52:22 -0400429 mnt_drop_write_file(f.file);
Dave Hansen18f335a2008-02-15 14:37:38 -0800430 }
Al Viro2903ff02012-08-28 12:52:22 -0400431 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432 return error;
433}
434
435/*
436 * Extended attribute GET operations
437 */
438static ssize_t
David Howells8f0cfa52008-04-29 00:59:41 -0700439getxattr(struct dentry *d, const char __user *name, void __user *value,
440 size_t size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441{
442 ssize_t error;
443 void *kvalue = NULL;
Sasha Levin779302e2012-07-30 14:39:13 -0700444 void *vvalue = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700445 char kname[XATTR_NAME_MAX + 1];
446
447 error = strncpy_from_user(kname, name, sizeof(kname));
448 if (error == 0 || error == sizeof(kname))
449 error = -ERANGE;
450 if (error < 0)
451 return error;
452
453 if (size) {
454 if (size > XATTR_SIZE_MAX)
455 size = XATTR_SIZE_MAX;
Sasha Levin779302e2012-07-30 14:39:13 -0700456 kvalue = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);
457 if (!kvalue) {
458 vvalue = vmalloc(size);
459 if (!vvalue)
460 return -ENOMEM;
461 kvalue = vvalue;
462 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463 }
464
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800465 error = vfs_getxattr(d, kname, kvalue, size);
Stephen Smalleyf549d6c2005-09-03 15:55:18 -0700466 if (error > 0) {
Eric W. Biederman2f6f0652012-02-07 18:52:57 -0800467 if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
468 (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
469 posix_acl_fix_xattr_to_user(kvalue, size);
Stephen Smalleyf549d6c2005-09-03 15:55:18 -0700470 if (size && copy_to_user(value, kvalue, error))
471 error = -EFAULT;
472 } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) {
473 /* The file system tried to returned a value bigger
474 than XATTR_SIZE_MAX bytes. Not possible. */
475 error = -E2BIG;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476 }
Sasha Levin779302e2012-07-30 14:39:13 -0700477 if (vvalue)
478 vfree(vvalue);
479 else
480 kfree(kvalue);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481 return error;
482}
483
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100484SYSCALL_DEFINE4(getxattr, const char __user *, pathname,
485 const char __user *, name, void __user *, value, size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700486{
Al Viro2d8f3032008-07-22 09:59:21 -0400487 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488 ssize_t error;
Jeff Layton60e66b42012-12-11 12:10:16 -0500489 unsigned int lookup_flags = LOOKUP_FOLLOW;
490retry:
491 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492 if (error)
493 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400494 error = getxattr(path.dentry, name, value, size);
495 path_put(&path);
Jeff Layton60e66b42012-12-11 12:10:16 -0500496 if (retry_estale(error, lookup_flags)) {
497 lookup_flags |= LOOKUP_REVAL;
498 goto retry;
499 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500 return error;
501}
502
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100503SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname,
504 const char __user *, name, void __user *, value, size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700505{
Al Viro2d8f3032008-07-22 09:59:21 -0400506 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700507 ssize_t error;
Jeff Layton3a3e1592012-12-11 12:10:16 -0500508 unsigned int lookup_flags = 0;
509retry:
510 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511 if (error)
512 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400513 error = getxattr(path.dentry, name, value, size);
514 path_put(&path);
Jeff Layton3a3e1592012-12-11 12:10:16 -0500515 if (retry_estale(error, lookup_flags)) {
516 lookup_flags |= LOOKUP_REVAL;
517 goto retry;
518 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519 return error;
520}
521
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100522SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name,
523 void __user *, value, size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524{
Al Viro2903ff02012-08-28 12:52:22 -0400525 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700526 ssize_t error = -EBADF;
527
Al Viro2903ff02012-08-28 12:52:22 -0400528 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529 return error;
Jeff Laytonbfcec702012-10-10 15:25:23 -0400530 audit_inode(NULL, f.file->f_path.dentry, 0);
Al Viro2903ff02012-08-28 12:52:22 -0400531 error = getxattr(f.file->f_path.dentry, name, value, size);
532 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533 return error;
534}
535
536/*
537 * Extended attribute LIST operations
538 */
539static ssize_t
540listxattr(struct dentry *d, char __user *list, size_t size)
541{
542 ssize_t error;
543 char *klist = NULL;
Andrew Morton0d08d7b2012-04-05 14:25:07 -0700544 char *vlist = NULL; /* If non-NULL, we used vmalloc() */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545
546 if (size) {
547 if (size > XATTR_LIST_MAX)
548 size = XATTR_LIST_MAX;
Dave Jones703bf2d2012-04-05 14:25:06 -0700549 klist = kmalloc(size, __GFP_NOWARN | GFP_KERNEL);
Andrew Morton0d08d7b2012-04-05 14:25:07 -0700550 if (!klist) {
551 vlist = vmalloc(size);
552 if (!vlist)
553 return -ENOMEM;
554 klist = vlist;
555 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556 }
557
Bill Nottingham659564c2006-10-09 16:10:48 -0400558 error = vfs_listxattr(d, klist, size);
Stephen Smalleyf549d6c2005-09-03 15:55:18 -0700559 if (error > 0) {
560 if (size && copy_to_user(list, klist, error))
561 error = -EFAULT;
562 } else if (error == -ERANGE && size >= XATTR_LIST_MAX) {
563 /* The file system tried to returned a list bigger
564 than XATTR_LIST_MAX bytes. Not possible. */
565 error = -E2BIG;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566 }
Andrew Morton0d08d7b2012-04-05 14:25:07 -0700567 if (vlist)
568 vfree(vlist);
569 else
570 kfree(klist);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700571 return error;
572}
573
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100574SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list,
575 size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700576{
Al Viro2d8f3032008-07-22 09:59:21 -0400577 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578 ssize_t error;
Jeff Layton10a90cf2012-12-11 12:10:16 -0500579 unsigned int lookup_flags = LOOKUP_FOLLOW;
580retry:
581 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700582 if (error)
583 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400584 error = listxattr(path.dentry, list, size);
585 path_put(&path);
Jeff Layton10a90cf2012-12-11 12:10:16 -0500586 if (retry_estale(error, lookup_flags)) {
587 lookup_flags |= LOOKUP_REVAL;
588 goto retry;
589 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590 return error;
591}
592
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100593SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list,
594 size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595{
Al Viro2d8f3032008-07-22 09:59:21 -0400596 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597 ssize_t error;
Jeff Laytonbd9bbc92012-12-11 12:10:17 -0500598 unsigned int lookup_flags = 0;
599retry:
600 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700601 if (error)
602 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400603 error = listxattr(path.dentry, list, size);
604 path_put(&path);
Jeff Laytonbd9bbc92012-12-11 12:10:17 -0500605 if (retry_estale(error, lookup_flags)) {
606 lookup_flags |= LOOKUP_REVAL;
607 goto retry;
608 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609 return error;
610}
611
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100612SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700613{
Al Viro2903ff02012-08-28 12:52:22 -0400614 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700615 ssize_t error = -EBADF;
616
Al Viro2903ff02012-08-28 12:52:22 -0400617 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618 return error;
Jeff Laytonbfcec702012-10-10 15:25:23 -0400619 audit_inode(NULL, f.file->f_path.dentry, 0);
Al Viro2903ff02012-08-28 12:52:22 -0400620 error = listxattr(f.file->f_path.dentry, list, size);
621 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622 return error;
623}
624
625/*
626 * Extended attribute REMOVE operations
627 */
628static long
David Howells8f0cfa52008-04-29 00:59:41 -0700629removexattr(struct dentry *d, const char __user *name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700630{
631 int error;
632 char kname[XATTR_NAME_MAX + 1];
633
634 error = strncpy_from_user(kname, name, sizeof(kname));
635 if (error == 0 || error == sizeof(kname))
636 error = -ERANGE;
637 if (error < 0)
638 return error;
639
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800640 return vfs_removexattr(d, kname);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641}
642
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100643SYSCALL_DEFINE2(removexattr, const char __user *, pathname,
644 const char __user *, name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700645{
Al Viro2d8f3032008-07-22 09:59:21 -0400646 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647 int error;
Jeff Layton12f06212012-12-11 12:10:17 -0500648 unsigned int lookup_flags = LOOKUP_FOLLOW;
649retry:
650 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700651 if (error)
652 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400653 error = mnt_want_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800654 if (!error) {
Al Viro2d8f3032008-07-22 09:59:21 -0400655 error = removexattr(path.dentry, name);
656 mnt_drop_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800657 }
Al Viro2d8f3032008-07-22 09:59:21 -0400658 path_put(&path);
Jeff Layton12f06212012-12-11 12:10:17 -0500659 if (retry_estale(error, lookup_flags)) {
660 lookup_flags |= LOOKUP_REVAL;
661 goto retry;
662 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700663 return error;
664}
665
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100666SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname,
667 const char __user *, name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668{
Al Viro2d8f3032008-07-22 09:59:21 -0400669 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670 int error;
Jeff Laytonb729d752012-12-11 12:10:18 -0500671 unsigned int lookup_flags = 0;
672retry:
673 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700674 if (error)
675 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400676 error = mnt_want_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800677 if (!error) {
Al Viro2d8f3032008-07-22 09:59:21 -0400678 error = removexattr(path.dentry, name);
679 mnt_drop_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800680 }
Al Viro2d8f3032008-07-22 09:59:21 -0400681 path_put(&path);
Jeff Laytonb729d752012-12-11 12:10:18 -0500682 if (retry_estale(error, lookup_flags)) {
683 lookup_flags |= LOOKUP_REVAL;
684 goto retry;
685 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686 return error;
687}
688
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100689SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690{
Al Viro2903ff02012-08-28 12:52:22 -0400691 struct fd f = fdget(fd);
Amy Griffis73241cc2005-11-03 16:00:25 +0000692 struct dentry *dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700693 int error = -EBADF;
694
Al Viro2903ff02012-08-28 12:52:22 -0400695 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696 return error;
Al Viro2903ff02012-08-28 12:52:22 -0400697 dentry = f.file->f_path.dentry;
Jeff Laytonbfcec702012-10-10 15:25:23 -0400698 audit_inode(NULL, dentry, 0);
Al Viro2903ff02012-08-28 12:52:22 -0400699 error = mnt_want_write_file(f.file);
Dave Hansen18f335a2008-02-15 14:37:38 -0800700 if (!error) {
701 error = removexattr(dentry, name);
Al Viro2903ff02012-08-28 12:52:22 -0400702 mnt_drop_write_file(f.file);
Dave Hansen18f335a2008-02-15 14:37:38 -0800703 }
Al Viro2903ff02012-08-28 12:52:22 -0400704 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705 return error;
706}
707
708
709static const char *
710strcmp_prefix(const char *a, const char *a_prefix)
711{
712 while (*a_prefix && *a == *a_prefix) {
713 a++;
714 a_prefix++;
715 }
716 return *a_prefix ? NULL : a;
717}
718
719/*
720 * In order to implement different sets of xattr operations for each xattr
721 * prefix with the generic xattr API, a filesystem should create a
722 * null-terminated array of struct xattr_handler (one for each prefix) and
723 * hang a pointer to it off of the s_xattr field of the superblock.
724 *
725 * The generic_fooxattr() functions will use this list to dispatch xattr
726 * operations to the correct xattr_handler.
727 */
728#define for_each_xattr_handler(handlers, handler) \
729 for ((handler) = *(handlers)++; \
730 (handler) != NULL; \
731 (handler) = *(handlers)++)
732
733/*
734 * Find the xattr_handler with the matching prefix.
735 */
Stephen Hemmingerbb435452010-05-13 17:53:14 -0700736static const struct xattr_handler *
737xattr_resolve_name(const struct xattr_handler **handlers, const char **name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700738{
Stephen Hemmingerbb435452010-05-13 17:53:14 -0700739 const struct xattr_handler *handler;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740
741 if (!*name)
742 return NULL;
743
744 for_each_xattr_handler(handlers, handler) {
745 const char *n = strcmp_prefix(*name, handler->prefix);
746 if (n) {
747 *name = n;
748 break;
749 }
750 }
751 return handler;
752}
753
754/*
755 * Find the handler for the prefix and dispatch its get() operation.
756 */
757ssize_t
758generic_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size)
759{
Stephen Hemmingerbb435452010-05-13 17:53:14 -0700760 const struct xattr_handler *handler;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700761
Christoph Hellwig431547b2009-11-13 09:52:56 +0000762 handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700763 if (!handler)
764 return -EOPNOTSUPP;
Christoph Hellwig431547b2009-11-13 09:52:56 +0000765 return handler->get(dentry, name, buffer, size, handler->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700766}
767
768/*
769 * Combine the results of the list() operation from every xattr_handler in the
770 * list.
771 */
772ssize_t
773generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
774{
Stephen Hemmingerbb435452010-05-13 17:53:14 -0700775 const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700776 unsigned int size = 0;
777
778 if (!buffer) {
Christoph Hellwig431547b2009-11-13 09:52:56 +0000779 for_each_xattr_handler(handlers, handler) {
780 size += handler->list(dentry, NULL, 0, NULL, 0,
781 handler->flags);
782 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700783 } else {
784 char *buf = buffer;
785
786 for_each_xattr_handler(handlers, handler) {
Christoph Hellwig431547b2009-11-13 09:52:56 +0000787 size = handler->list(dentry, buf, buffer_size,
788 NULL, 0, handler->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700789 if (size > buffer_size)
790 return -ERANGE;
791 buf += size;
792 buffer_size -= size;
793 }
794 size = buf - buffer;
795 }
796 return size;
797}
798
799/*
800 * Find the handler for the prefix and dispatch its set() operation.
801 */
802int
803generic_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags)
804{
Stephen Hemmingerbb435452010-05-13 17:53:14 -0700805 const struct xattr_handler *handler;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700806
807 if (size == 0)
808 value = ""; /* empty EA, do not remove */
Christoph Hellwig431547b2009-11-13 09:52:56 +0000809 handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700810 if (!handler)
811 return -EOPNOTSUPP;
Jan Karadf7e1302011-04-20 20:30:40 +0200812 return handler->set(dentry, name, value, size, flags, handler->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700813}
814
815/*
816 * Find the handler for the prefix and dispatch its set() operation to remove
817 * any associated extended attribute.
818 */
819int
820generic_removexattr(struct dentry *dentry, const char *name)
821{
Stephen Hemmingerbb435452010-05-13 17:53:14 -0700822 const struct xattr_handler *handler;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700823
Christoph Hellwig431547b2009-11-13 09:52:56 +0000824 handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700825 if (!handler)
826 return -EOPNOTSUPP;
Christoph Hellwig431547b2009-11-13 09:52:56 +0000827 return handler->set(dentry, name, NULL, 0,
828 XATTR_REPLACE, handler->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700829}
830
831EXPORT_SYMBOL(generic_getxattr);
832EXPORT_SYMBOL(generic_listxattr);
833EXPORT_SYMBOL(generic_setxattr);
834EXPORT_SYMBOL(generic_removexattr);
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400835
836/*
837 * Allocate new xattr and copy in the value; but leave the name to callers.
838 */
839struct simple_xattr *simple_xattr_alloc(const void *value, size_t size)
840{
841 struct simple_xattr *new_xattr;
842 size_t len;
843
844 /* wrap around? */
845 len = sizeof(*new_xattr) + size;
Hugh Dickins4e66d442014-07-23 14:00:17 -0700846 if (len < sizeof(*new_xattr))
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400847 return NULL;
848
849 new_xattr = kmalloc(len, GFP_KERNEL);
850 if (!new_xattr)
851 return NULL;
852
853 new_xattr->size = size;
854 memcpy(new_xattr->value, value, size);
855 return new_xattr;
856}
857
858/*
859 * xattr GET operation for in-memory/pseudo filesystems
860 */
861int simple_xattr_get(struct simple_xattrs *xattrs, const char *name,
862 void *buffer, size_t size)
863{
864 struct simple_xattr *xattr;
865 int ret = -ENODATA;
866
867 spin_lock(&xattrs->lock);
868 list_for_each_entry(xattr, &xattrs->head, list) {
869 if (strcmp(name, xattr->name))
870 continue;
871
872 ret = xattr->size;
873 if (buffer) {
874 if (size < xattr->size)
875 ret = -ERANGE;
876 else
877 memcpy(buffer, xattr->value, xattr->size);
878 }
879 break;
880 }
881 spin_unlock(&xattrs->lock);
882 return ret;
883}
884
885static int __simple_xattr_set(struct simple_xattrs *xattrs, const char *name,
886 const void *value, size_t size, int flags)
887{
888 struct simple_xattr *xattr;
David Rientjes43385842012-10-17 20:41:15 -0700889 struct simple_xattr *new_xattr = NULL;
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400890 int err = 0;
891
892 /* value == NULL means remove */
893 if (value) {
894 new_xattr = simple_xattr_alloc(value, size);
895 if (!new_xattr)
896 return -ENOMEM;
897
898 new_xattr->name = kstrdup(name, GFP_KERNEL);
899 if (!new_xattr->name) {
900 kfree(new_xattr);
901 return -ENOMEM;
902 }
903 }
904
905 spin_lock(&xattrs->lock);
906 list_for_each_entry(xattr, &xattrs->head, list) {
907 if (!strcmp(name, xattr->name)) {
908 if (flags & XATTR_CREATE) {
909 xattr = new_xattr;
910 err = -EEXIST;
911 } else if (new_xattr) {
912 list_replace(&xattr->list, &new_xattr->list);
913 } else {
914 list_del(&xattr->list);
915 }
916 goto out;
917 }
918 }
919 if (flags & XATTR_REPLACE) {
920 xattr = new_xattr;
921 err = -ENODATA;
922 } else {
923 list_add(&new_xattr->list, &xattrs->head);
924 xattr = NULL;
925 }
926out:
927 spin_unlock(&xattrs->lock);
928 if (xattr) {
929 kfree(xattr->name);
930 kfree(xattr);
931 }
932 return err;
933
934}
935
Aristeu Rozanski48957682012-09-11 16:28:11 -0400936/**
937 * simple_xattr_set - xattr SET operation for in-memory/pseudo filesystems
938 * @xattrs: target simple_xattr list
939 * @name: name of the new extended attribute
940 * @value: value of the new xattr. If %NULL, will remove the attribute
941 * @size: size of the new xattr
942 * @flags: %XATTR_{CREATE|REPLACE}
943 *
944 * %XATTR_CREATE is set, the xattr shouldn't exist already; otherwise fails
945 * with -EEXIST. If %XATTR_REPLACE is set, the xattr should exist;
946 * otherwise, fails with -ENODATA.
947 *
948 * Returns 0 on success, -errno on failure.
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400949 */
950int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,
951 const void *value, size_t size, int flags)
952{
953 if (size == 0)
954 value = ""; /* empty EA, do not remove */
955 return __simple_xattr_set(xattrs, name, value, size, flags);
956}
957
958/*
959 * xattr REMOVE operation for in-memory/pseudo filesystems
960 */
961int simple_xattr_remove(struct simple_xattrs *xattrs, const char *name)
962{
963 return __simple_xattr_set(xattrs, name, NULL, 0, XATTR_REPLACE);
964}
965
966static bool xattr_is_trusted(const char *name)
967{
968 return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN);
969}
970
971/*
972 * xattr LIST operation for in-memory/pseudo filesystems
973 */
974ssize_t simple_xattr_list(struct simple_xattrs *xattrs, char *buffer,
975 size_t size)
976{
977 bool trusted = capable(CAP_SYS_ADMIN);
978 struct simple_xattr *xattr;
979 size_t used = 0;
980
981 spin_lock(&xattrs->lock);
982 list_for_each_entry(xattr, &xattrs->head, list) {
983 size_t len;
984
985 /* skip "trusted." attributes for unprivileged callers */
986 if (!trusted && xattr_is_trusted(xattr->name))
987 continue;
988
989 len = strlen(xattr->name) + 1;
990 used += len;
991 if (buffer) {
992 if (size < used) {
993 used = -ERANGE;
994 break;
995 }
996 memcpy(buffer, xattr->name, len);
997 buffer += len;
998 }
999 }
1000 spin_unlock(&xattrs->lock);
1001
1002 return used;
1003}
1004
Aristeu Rozanski48957682012-09-11 16:28:11 -04001005/*
1006 * Adds an extended attribute to the list
1007 */
Aristeu Rozanski38f38652012-08-23 16:53:28 -04001008void simple_xattr_list_add(struct simple_xattrs *xattrs,
1009 struct simple_xattr *new_xattr)
1010{
1011 spin_lock(&xattrs->lock);
1012 list_add(&new_xattr->list, &xattrs->head);
1013 spin_unlock(&xattrs->lock);
1014}