blob: 3a24027c062ddcb25e5a3f101ab140a92e232b28 [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
Linus Torvalds7c0f6ba2016-12-24 11:46:01 -080025#include <linux/uaccess.h>
Christoph Hellwig5be196e2006-01-09 20:51:55 -080026
Andreas Gruenbacherb6ba1172016-09-29 17:48:38 +020027static const char *
28strcmp_prefix(const char *a, const char *a_prefix)
29{
30 while (*a_prefix && *a == *a_prefix) {
31 a++;
32 a_prefix++;
33 }
34 return *a_prefix ? NULL : a;
35}
36
37/*
38 * In order to implement different sets of xattr operations for each xattr
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +020039 * prefix, a filesystem should create a null-terminated array of struct
40 * xattr_handler (one for each prefix) and hang a pointer to it off of the
41 * s_xattr field of the superblock.
Andreas Gruenbacherb6ba1172016-09-29 17:48:38 +020042 */
43#define for_each_xattr_handler(handlers, handler) \
44 if (handlers) \
45 for ((handler) = *(handlers)++; \
46 (handler) != NULL; \
47 (handler) = *(handlers)++)
48
49/*
50 * Find the xattr_handler with the matching prefix.
51 */
52static const struct xattr_handler *
Andreas Gruenbacherd0a5b992016-09-29 17:48:39 +020053xattr_resolve_name(struct inode *inode, const char **name)
Andreas Gruenbacherb6ba1172016-09-29 17:48:38 +020054{
Andreas Gruenbacherd0a5b992016-09-29 17:48:39 +020055 const struct xattr_handler **handlers = inode->i_sb->s_xattr;
Andreas Gruenbacherb6ba1172016-09-29 17:48:38 +020056 const struct xattr_handler *handler;
57
Andreas Gruenbacher5f6e59a2016-09-29 17:48:40 +020058 if (!(inode->i_opflags & IOP_XATTR)) {
59 if (unlikely(is_bad_inode(inode)))
60 return ERR_PTR(-EIO);
Andreas Gruenbacherd0a5b992016-09-29 17:48:39 +020061 return ERR_PTR(-EOPNOTSUPP);
Andreas Gruenbacher5f6e59a2016-09-29 17:48:40 +020062 }
Andreas Gruenbacherb6ba1172016-09-29 17:48:38 +020063 for_each_xattr_handler(handlers, handler) {
64 const char *n;
65
66 n = strcmp_prefix(*name, xattr_prefix(handler));
67 if (n) {
68 if (!handler->prefix ^ !*n) {
69 if (*n)
70 continue;
71 return ERR_PTR(-EINVAL);
72 }
73 *name = n;
74 return handler;
75 }
76 }
77 return ERR_PTR(-EOPNOTSUPP);
78}
79
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -080080/*
81 * Check permissions for extended attribute access. This is a bit complicated
82 * because different namespaces have very different rules.
83 */
84static int
85xattr_permission(struct inode *inode, const char *name, int mask)
86{
87 /*
88 * We can never set or remove an extended attribute on a read-only
89 * filesystem or on an immutable / append-only inode.
90 */
91 if (mask & MAY_WRITE) {
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -080092 if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
93 return -EPERM;
Eric W. Biederman0bd23d092016-06-29 14:54:46 -050094 /*
95 * Updating an xattr will likely cause i_uid and i_gid
96 * to be writen back improperly if their true value is
97 * unknown to the vfs.
98 */
99 if (HAS_UNMAPPED_ID(inode))
100 return -EPERM;
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800101 }
102
103 /*
104 * No restriction for security.* and system.* from the VFS. Decision
105 * on these is left to the underlying filesystem / security module.
106 */
107 if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) ||
108 !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
109 return 0;
110
111 /*
Andreas Gruenbacher55b23bd2011-05-27 14:50:36 +0200112 * The trusted.* namespace can only be accessed by privileged users.
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800113 */
Andreas Gruenbacher55b23bd2011-05-27 14:50:36 +0200114 if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) {
115 if (!capable(CAP_SYS_ADMIN))
116 return (mask & MAY_WRITE) ? -EPERM : -ENODATA;
117 return 0;
118 }
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800119
Andreas Gruenbacher55b23bd2011-05-27 14:50:36 +0200120 /*
121 * In the user.* namespace, only regular files and directories can have
Andreas Gruenbacherf1f2d872006-11-02 22:07:29 -0800122 * extended attributes. For sticky directories, only the owner and
Andreas Gruenbacher55b23bd2011-05-27 14:50:36 +0200123 * privileged users can write attributes.
Andreas Gruenbacherf1f2d872006-11-02 22:07:29 -0800124 */
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800125 if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) {
Andreas Gruenbacherf1f2d872006-11-02 22:07:29 -0800126 if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
Andreas Gruenbacher55b23bd2011-05-27 14:50:36 +0200127 return (mask & MAY_WRITE) ? -EPERM : -ENODATA;
Andreas Gruenbacherf1f2d872006-11-02 22:07:29 -0800128 if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) &&
Serge E. Hallyn2e149672011-03-23 16:43:26 -0700129 (mask & MAY_WRITE) && !inode_owner_or_capable(inode))
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800130 return -EPERM;
131 }
132
Al Virof419a2e2008-07-22 00:07:17 -0400133 return inode_permission(inode, mask);
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800134}
135
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200136int
137__vfs_setxattr(struct dentry *dentry, struct inode *inode, const char *name,
138 const void *value, size_t size, int flags)
139{
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200140 const struct xattr_handler *handler;
141
142 handler = xattr_resolve_name(inode, &name);
143 if (IS_ERR(handler))
144 return PTR_ERR(handler);
145 if (!handler->set)
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200146 return -EOPNOTSUPP;
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200147 if (size == 0)
148 value = ""; /* empty EA, do not remove */
149 return handler->set(handler, dentry, inode, name, value, size, flags);
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200150}
151EXPORT_SYMBOL(__vfs_setxattr);
152
David P. Quigleyb1ab7e42009-09-03 14:25:56 -0400153/**
154 * __vfs_setxattr_noperm - perform setxattr operation without performing
155 * permission checks.
156 *
157 * @dentry - object to perform setxattr on
158 * @name - xattr name to set
159 * @value - value to set @name to
160 * @size - size of @value
161 * @flags - flags to pass into filesystem operations
162 *
163 * returns the result of the internal setxattr or setsecurity operations.
164 *
165 * This function requires the caller to lock the inode's i_mutex before it
166 * is executed. It also assumes that the caller will make the appropriate
167 * permission checks.
168 */
169int __vfs_setxattr_noperm(struct dentry *dentry, const char *name,
170 const void *value, size_t size, int flags)
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800171{
172 struct inode *inode = dentry->d_inode;
Andreas Gruenbacher4a590152016-11-13 21:23:34 +0100173 int error = -EAGAIN;
Andi Kleen69b45732011-05-28 08:25:51 -0700174 int issec = !strncmp(name, XATTR_SECURITY_PREFIX,
175 XATTR_SECURITY_PREFIX_LEN);
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800176
Andi Kleen69b45732011-05-28 08:25:51 -0700177 if (issec)
178 inode->i_flags &= ~S_NOSEC;
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200179 if (inode->i_opflags & IOP_XATTR) {
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200180 error = __vfs_setxattr(dentry, inode, name, value, size, flags);
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800181 if (!error) {
182 fsnotify_xattr(dentry);
183 security_inode_post_setxattr(dentry, name, value,
184 size, flags);
185 }
Andreas Gruenbacher4a590152016-11-13 21:23:34 +0100186 } else {
Andreas Gruenbacher5f6e59a2016-09-29 17:48:40 +0200187 if (unlikely(is_bad_inode(inode)))
188 return -EIO;
Andreas Gruenbacher4a590152016-11-13 21:23:34 +0100189 }
190 if (error == -EAGAIN) {
191 error = -EOPNOTSUPP;
192
193 if (issec) {
194 const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
195
196 error = security_inode_setsecurity(inode, suffix, value,
197 size, flags);
198 if (!error)
199 fsnotify_xattr(dentry);
200 }
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800201 }
David P. Quigleyb1ab7e42009-09-03 14:25:56 -0400202
203 return error;
204}
205
206
207int
208vfs_setxattr(struct dentry *dentry, const char *name, const void *value,
209 size_t size, int flags)
210{
211 struct inode *inode = dentry->d_inode;
212 int error;
213
214 error = xattr_permission(inode, name, MAY_WRITE);
215 if (error)
216 return error;
217
Al Viro59551022016-01-22 15:40:57 -0500218 inode_lock(inode);
David P. Quigleyb1ab7e42009-09-03 14:25:56 -0400219 error = security_inode_setxattr(dentry, name, value, size, flags);
220 if (error)
221 goto out;
222
223 error = __vfs_setxattr_noperm(dentry, name, value, size, flags);
224
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800225out:
Al Viro59551022016-01-22 15:40:57 -0500226 inode_unlock(inode);
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800227 return error;
228}
229EXPORT_SYMBOL_GPL(vfs_setxattr);
230
Al Viro2220c5b2018-04-24 21:22:04 -0400231static ssize_t
David P. Quigley42492592008-02-04 22:29:39 -0800232xattr_getsecurity(struct inode *inode, const char *name, void *value,
233 size_t size)
234{
235 void *buffer = NULL;
236 ssize_t len;
237
238 if (!value || !size) {
239 len = security_inode_getsecurity(inode, name, &buffer, false);
240 goto out_noalloc;
241 }
242
243 len = security_inode_getsecurity(inode, name, &buffer, true);
244 if (len < 0)
245 return len;
246 if (size < len) {
247 len = -ERANGE;
248 goto out;
249 }
250 memcpy(value, buffer, len);
251out:
Casey Schaufler57e7ba02017-09-19 09:39:08 -0700252 kfree(buffer);
David P. Quigley42492592008-02-04 22:29:39 -0800253out_noalloc:
254 return len;
255}
David P. Quigley42492592008-02-04 22:29:39 -0800256
Mimi Zohar1601fba2011-03-09 14:23:34 -0500257/*
258 * vfs_getxattr_alloc - allocate memory, if necessary, before calling getxattr
259 *
260 * Allocate memory, if not already allocated, or re-allocate correct size,
261 * before retrieving the extended attribute.
262 *
263 * Returns the result of alloc, if failed, or the getxattr operation.
264 */
265ssize_t
266vfs_getxattr_alloc(struct dentry *dentry, const char *name, char **xattr_value,
267 size_t xattr_size, gfp_t flags)
268{
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200269 const struct xattr_handler *handler;
Mimi Zohar1601fba2011-03-09 14:23:34 -0500270 struct inode *inode = dentry->d_inode;
271 char *value = *xattr_value;
272 int error;
273
274 error = xattr_permission(inode, name, MAY_READ);
275 if (error)
276 return error;
277
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200278 handler = xattr_resolve_name(inode, &name);
279 if (IS_ERR(handler))
280 return PTR_ERR(handler);
281 if (!handler->get)
Mimi Zohar1601fba2011-03-09 14:23:34 -0500282 return -EOPNOTSUPP;
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200283 error = handler->get(handler, dentry, inode, name, NULL, 0);
Mimi Zohar1601fba2011-03-09 14:23:34 -0500284 if (error < 0)
285 return error;
286
287 if (!value || (error > xattr_size)) {
288 value = krealloc(*xattr_value, error + 1, flags);
289 if (!value)
290 return -ENOMEM;
291 memset(value, 0, error + 1);
292 }
293
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200294 error = handler->get(handler, dentry, inode, name, value, error);
Mimi Zohar1601fba2011-03-09 14:23:34 -0500295 *xattr_value = value;
296 return error;
297}
298
David P. Quigley42492592008-02-04 22:29:39 -0800299ssize_t
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200300__vfs_getxattr(struct dentry *dentry, struct inode *inode, const char *name,
301 void *value, size_t size)
302{
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200303 const struct xattr_handler *handler;
304
305 handler = xattr_resolve_name(inode, &name);
306 if (IS_ERR(handler))
307 return PTR_ERR(handler);
308 if (!handler->get)
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200309 return -EOPNOTSUPP;
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200310 return handler->get(handler, dentry, inode, name, value, size);
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200311}
312EXPORT_SYMBOL(__vfs_getxattr);
313
314ssize_t
David Howells8f0cfa52008-04-29 00:59:41 -0700315vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size)
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800316{
317 struct inode *inode = dentry->d_inode;
318 int error;
319
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800320 error = xattr_permission(inode, name, MAY_READ);
321 if (error)
322 return error;
323
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800324 error = security_inode_getxattr(dentry, name);
325 if (error)
326 return error;
327
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800328 if (!strncmp(name, XATTR_SECURITY_PREFIX,
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800329 XATTR_SECURITY_PREFIX_LEN)) {
330 const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
David P. Quigley42492592008-02-04 22:29:39 -0800331 int ret = xattr_getsecurity(inode, suffix, value, size);
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800332 /*
333 * Only overwrite the return value if a security module
334 * is actually active.
335 */
David P. Quigley4bea5802008-02-04 22:29:40 -0800336 if (ret == -EOPNOTSUPP)
337 goto nolsm;
338 return ret;
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800339 }
David P. Quigley4bea5802008-02-04 22:29:40 -0800340nolsm:
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200341 return __vfs_getxattr(dentry, inode, name, value, size);
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800342}
343EXPORT_SYMBOL_GPL(vfs_getxattr);
344
Bill Nottingham659564c2006-10-09 16:10:48 -0400345ssize_t
Andreas Gruenbacherbf3ee712016-09-29 17:48:43 +0200346vfs_listxattr(struct dentry *dentry, char *list, size_t size)
Bill Nottingham659564c2006-10-09 16:10:48 -0400347{
Andreas Gruenbacherbf3ee712016-09-29 17:48:43 +0200348 struct inode *inode = d_inode(dentry);
Bill Nottingham659564c2006-10-09 16:10:48 -0400349 ssize_t error;
350
Andreas Gruenbacherbf3ee712016-09-29 17:48:43 +0200351 error = security_inode_listxattr(dentry);
Bill Nottingham659564c2006-10-09 16:10:48 -0400352 if (error)
353 return error;
Andreas Gruenbacherbf3ee712016-09-29 17:48:43 +0200354 if (inode->i_op->listxattr && (inode->i_opflags & IOP_XATTR)) {
Andreas Gruenbacherbf3ee712016-09-29 17:48:43 +0200355 error = inode->i_op->listxattr(dentry, list, size);
Bill Nottingham659564c2006-10-09 16:10:48 -0400356 } else {
Andreas Gruenbacherbf3ee712016-09-29 17:48:43 +0200357 error = security_inode_listsecurity(inode, list, size);
Bill Nottingham659564c2006-10-09 16:10:48 -0400358 if (size && error > size)
359 error = -ERANGE;
360 }
361 return error;
362}
363EXPORT_SYMBOL_GPL(vfs_listxattr);
364
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800365int
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200366__vfs_removexattr(struct dentry *dentry, const char *name)
367{
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200368 struct inode *inode = d_inode(dentry);
369 const struct xattr_handler *handler;
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200370
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200371 handler = xattr_resolve_name(inode, &name);
372 if (IS_ERR(handler))
373 return PTR_ERR(handler);
374 if (!handler->set)
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200375 return -EOPNOTSUPP;
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200376 return handler->set(handler, dentry, inode, name, NULL, 0, XATTR_REPLACE);
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200377}
378EXPORT_SYMBOL(__vfs_removexattr);
379
380int
David Howells8f0cfa52008-04-29 00:59:41 -0700381vfs_removexattr(struct dentry *dentry, const char *name)
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800382{
383 struct inode *inode = dentry->d_inode;
384 int error;
385
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800386 error = xattr_permission(inode, name, MAY_WRITE);
387 if (error)
388 return error;
389
Al Viro59551022016-01-22 15:40:57 -0500390 inode_lock(inode);
Mimi Zohar2ab51f32011-03-23 17:23:06 -0400391 error = security_inode_removexattr(dentry, name);
Dmitry Kasatkin7c51bb002014-11-20 16:31:01 +0200392 if (error)
393 goto out;
Mimi Zohar2ab51f32011-03-23 17:23:06 -0400394
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200395 error = __vfs_removexattr(dentry, name);
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800396
Mimi Zoharc7b87de2011-03-09 14:39:18 -0500397 if (!error) {
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800398 fsnotify_xattr(dentry);
Mimi Zoharc7b87de2011-03-09 14:39:18 -0500399 evm_inode_post_removexattr(dentry, name);
400 }
Dmitry Kasatkin7c51bb002014-11-20 16:31:01 +0200401
402out:
Al Viro59551022016-01-22 15:40:57 -0500403 inode_unlock(inode);
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800404 return error;
405}
406EXPORT_SYMBOL_GPL(vfs_removexattr);
407
408
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409/*
410 * Extended attribute SET operations
411 */
412static long
David Howells8f0cfa52008-04-29 00:59:41 -0700413setxattr(struct dentry *d, const char __user *name, const void __user *value,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700414 size_t size, int flags)
415{
416 int error;
417 void *kvalue = NULL;
418 char kname[XATTR_NAME_MAX + 1];
419
420 if (flags & ~(XATTR_CREATE|XATTR_REPLACE))
421 return -EINVAL;
422
423 error = strncpy_from_user(kname, name, sizeof(kname));
424 if (error == 0 || error == sizeof(kname))
425 error = -ERANGE;
426 if (error < 0)
427 return error;
428
429 if (size) {
430 if (size > XATTR_SIZE_MAX)
431 return -E2BIG;
Michal Hocko752ade62017-05-08 15:57:27 -0700432 kvalue = kvmalloc(size, GFP_KERNEL);
433 if (!kvalue)
434 return -ENOMEM;
Andrew Morton44c82492012-04-05 14:25:07 -0700435 if (copy_from_user(kvalue, value, size)) {
436 error = -EFAULT;
437 goto out;
438 }
Eric W. Biederman2f6f0652012-02-07 18:52:57 -0800439 if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
440 (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
441 posix_acl_fix_xattr_from_user(kvalue, size);
Serge E. Hallyn8db6c342017-05-08 13:11:56 -0500442 else if (strcmp(kname, XATTR_NAME_CAPS) == 0) {
443 error = cap_convert_nscap(d, &kvalue, size);
444 if (error < 0)
445 goto out;
446 size = error;
447 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448 }
449
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800450 error = vfs_setxattr(d, kname, kvalue, size, flags);
Andrew Morton44c82492012-04-05 14:25:07 -0700451out:
Richard Weinberger0b2a6f22016-01-02 23:09:47 +0100452 kvfree(kvalue);
453
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454 return error;
455}
456
Eric Biggers8cc43112014-10-12 11:59:58 -0500457static int path_setxattr(const char __user *pathname,
458 const char __user *name, const void __user *value,
459 size_t size, int flags, unsigned int lookup_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700460{
Al Viro2d8f3032008-07-22 09:59:21 -0400461 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700462 int error;
Jeff Layton68f1bb82012-12-11 12:10:15 -0500463retry:
464 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465 if (error)
466 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400467 error = mnt_want_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800468 if (!error) {
Al Viro2d8f3032008-07-22 09:59:21 -0400469 error = setxattr(path.dentry, name, value, size, flags);
470 mnt_drop_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800471 }
Al Viro2d8f3032008-07-22 09:59:21 -0400472 path_put(&path);
Jeff Layton68f1bb82012-12-11 12:10:15 -0500473 if (retry_estale(error, lookup_flags)) {
474 lookup_flags |= LOOKUP_REVAL;
475 goto retry;
476 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477 return error;
478}
479
Eric Biggers8cc43112014-10-12 11:59:58 -0500480SYSCALL_DEFINE5(setxattr, const char __user *, pathname,
481 const char __user *, name, const void __user *, value,
482 size_t, size, int, flags)
483{
484 return path_setxattr(pathname, name, value, size, flags, LOOKUP_FOLLOW);
485}
486
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100487SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname,
488 const char __user *, name, const void __user *, value,
489 size_t, size, int, flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700490{
Eric Biggers8cc43112014-10-12 11:59:58 -0500491 return path_setxattr(pathname, name, value, size, flags, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492}
493
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100494SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
495 const void __user *,value, size_t, size, int, flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700496{
Al Viro2903ff02012-08-28 12:52:22 -0400497 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700498 int error = -EBADF;
499
Al Viro2903ff02012-08-28 12:52:22 -0400500 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700501 return error;
Al Viro9f45f5b2014-10-31 17:44:57 -0400502 audit_file(f.file);
Miklos Szeredi6742cee2018-07-18 15:44:43 +0200503 error = mnt_want_write_file(f.file);
Dave Hansen18f335a2008-02-15 14:37:38 -0800504 if (!error) {
Al Viro9f45f5b2014-10-31 17:44:57 -0400505 error = setxattr(f.file->f_path.dentry, name, value, size, flags);
Miklos Szeredi6742cee2018-07-18 15:44:43 +0200506 mnt_drop_write_file(f.file);
Dave Hansen18f335a2008-02-15 14:37:38 -0800507 }
Al Viro2903ff02012-08-28 12:52:22 -0400508 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509 return error;
510}
511
512/*
513 * Extended attribute GET operations
514 */
515static ssize_t
David Howells8f0cfa52008-04-29 00:59:41 -0700516getxattr(struct dentry *d, const char __user *name, void __user *value,
517 size_t size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518{
519 ssize_t error;
520 void *kvalue = NULL;
521 char kname[XATTR_NAME_MAX + 1];
522
523 error = strncpy_from_user(kname, name, sizeof(kname));
524 if (error == 0 || error == sizeof(kname))
525 error = -ERANGE;
526 if (error < 0)
527 return error;
528
529 if (size) {
530 if (size > XATTR_SIZE_MAX)
531 size = XATTR_SIZE_MAX;
Michal Hocko752ade62017-05-08 15:57:27 -0700532 kvalue = kvzalloc(size, GFP_KERNEL);
533 if (!kvalue)
534 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700535 }
536
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800537 error = vfs_getxattr(d, kname, kvalue, size);
Stephen Smalleyf549d6c2005-09-03 15:55:18 -0700538 if (error > 0) {
Eric W. Biederman2f6f0652012-02-07 18:52:57 -0800539 if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
540 (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
541 posix_acl_fix_xattr_to_user(kvalue, size);
Stephen Smalleyf549d6c2005-09-03 15:55:18 -0700542 if (size && copy_to_user(value, kvalue, error))
543 error = -EFAULT;
544 } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) {
545 /* The file system tried to returned a value bigger
546 than XATTR_SIZE_MAX bytes. Not possible. */
547 error = -E2BIG;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548 }
Richard Weinberger0b2a6f22016-01-02 23:09:47 +0100549
550 kvfree(kvalue);
551
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552 return error;
553}
554
Eric Biggers8cc43112014-10-12 11:59:58 -0500555static ssize_t path_getxattr(const char __user *pathname,
556 const char __user *name, void __user *value,
557 size_t size, unsigned int lookup_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558{
Al Viro2d8f3032008-07-22 09:59:21 -0400559 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 ssize_t error;
Jeff Layton60e66b42012-12-11 12:10:16 -0500561retry:
562 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700563 if (error)
564 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400565 error = getxattr(path.dentry, name, value, size);
566 path_put(&path);
Jeff Layton60e66b42012-12-11 12:10:16 -0500567 if (retry_estale(error, lookup_flags)) {
568 lookup_flags |= LOOKUP_REVAL;
569 goto retry;
570 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700571 return error;
572}
573
Eric Biggers8cc43112014-10-12 11:59:58 -0500574SYSCALL_DEFINE4(getxattr, const char __user *, pathname,
575 const char __user *, name, void __user *, value, size_t, size)
576{
577 return path_getxattr(pathname, name, value, size, LOOKUP_FOLLOW);
578}
579
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100580SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname,
581 const char __user *, name, void __user *, value, size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700582{
Eric Biggers8cc43112014-10-12 11:59:58 -0500583 return path_getxattr(pathname, name, value, size, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584}
585
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100586SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name,
587 void __user *, value, size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588{
Al Viro2903ff02012-08-28 12:52:22 -0400589 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590 ssize_t error = -EBADF;
591
Al Viro2903ff02012-08-28 12:52:22 -0400592 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593 return error;
Al Viro9f45f5b2014-10-31 17:44:57 -0400594 audit_file(f.file);
Al Viro2903ff02012-08-28 12:52:22 -0400595 error = getxattr(f.file->f_path.dentry, name, value, size);
596 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597 return error;
598}
599
600/*
601 * Extended attribute LIST operations
602 */
603static ssize_t
604listxattr(struct dentry *d, char __user *list, size_t size)
605{
606 ssize_t error;
607 char *klist = NULL;
608
609 if (size) {
610 if (size > XATTR_LIST_MAX)
611 size = XATTR_LIST_MAX;
Michal Hocko752ade62017-05-08 15:57:27 -0700612 klist = kvmalloc(size, GFP_KERNEL);
613 if (!klist)
614 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700615 }
616
Bill Nottingham659564c2006-10-09 16:10:48 -0400617 error = vfs_listxattr(d, klist, size);
Stephen Smalleyf549d6c2005-09-03 15:55:18 -0700618 if (error > 0) {
619 if (size && copy_to_user(list, klist, error))
620 error = -EFAULT;
621 } else if (error == -ERANGE && size >= XATTR_LIST_MAX) {
622 /* The file system tried to returned a list bigger
623 than XATTR_LIST_MAX bytes. Not possible. */
624 error = -E2BIG;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700625 }
Richard Weinberger0b2a6f22016-01-02 23:09:47 +0100626
627 kvfree(klist);
628
Linus Torvalds1da177e2005-04-16 15:20:36 -0700629 return error;
630}
631
Eric Biggers8cc43112014-10-12 11:59:58 -0500632static ssize_t path_listxattr(const char __user *pathname, char __user *list,
633 size_t size, unsigned int lookup_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634{
Al Viro2d8f3032008-07-22 09:59:21 -0400635 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700636 ssize_t error;
Jeff Layton10a90cf2012-12-11 12:10:16 -0500637retry:
638 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700639 if (error)
640 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400641 error = listxattr(path.dentry, list, size);
642 path_put(&path);
Jeff Layton10a90cf2012-12-11 12:10:16 -0500643 if (retry_estale(error, lookup_flags)) {
644 lookup_flags |= LOOKUP_REVAL;
645 goto retry;
646 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647 return error;
648}
649
Eric Biggers8cc43112014-10-12 11:59:58 -0500650SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list,
651 size_t, size)
652{
653 return path_listxattr(pathname, list, size, LOOKUP_FOLLOW);
654}
655
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100656SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list,
657 size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700658{
Eric Biggers8cc43112014-10-12 11:59:58 -0500659 return path_listxattr(pathname, list, size, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660}
661
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100662SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700663{
Al Viro2903ff02012-08-28 12:52:22 -0400664 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665 ssize_t error = -EBADF;
666
Al Viro2903ff02012-08-28 12:52:22 -0400667 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668 return error;
Al Viro9f45f5b2014-10-31 17:44:57 -0400669 audit_file(f.file);
Al Viro2903ff02012-08-28 12:52:22 -0400670 error = listxattr(f.file->f_path.dentry, list, size);
671 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700672 return error;
673}
674
675/*
676 * Extended attribute REMOVE operations
677 */
678static long
David Howells8f0cfa52008-04-29 00:59:41 -0700679removexattr(struct dentry *d, const char __user *name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700680{
681 int error;
682 char kname[XATTR_NAME_MAX + 1];
683
684 error = strncpy_from_user(kname, name, sizeof(kname));
685 if (error == 0 || error == sizeof(kname))
686 error = -ERANGE;
687 if (error < 0)
688 return error;
689
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800690 return vfs_removexattr(d, kname);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700691}
692
Eric Biggers8cc43112014-10-12 11:59:58 -0500693static int path_removexattr(const char __user *pathname,
694 const char __user *name, unsigned int lookup_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700695{
Al Viro2d8f3032008-07-22 09:59:21 -0400696 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697 int error;
Jeff Layton12f06212012-12-11 12:10:17 -0500698retry:
699 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700 if (error)
701 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400702 error = mnt_want_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800703 if (!error) {
Al Viro2d8f3032008-07-22 09:59:21 -0400704 error = removexattr(path.dentry, name);
705 mnt_drop_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800706 }
Al Viro2d8f3032008-07-22 09:59:21 -0400707 path_put(&path);
Jeff Layton12f06212012-12-11 12:10:17 -0500708 if (retry_estale(error, lookup_flags)) {
709 lookup_flags |= LOOKUP_REVAL;
710 goto retry;
711 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712 return error;
713}
714
Eric Biggers8cc43112014-10-12 11:59:58 -0500715SYSCALL_DEFINE2(removexattr, const char __user *, pathname,
716 const char __user *, name)
717{
718 return path_removexattr(pathname, name, LOOKUP_FOLLOW);
719}
720
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100721SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname,
722 const char __user *, name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700723{
Eric Biggers8cc43112014-10-12 11:59:58 -0500724 return path_removexattr(pathname, name, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725}
726
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100727SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728{
Al Viro2903ff02012-08-28 12:52:22 -0400729 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730 int error = -EBADF;
731
Al Viro2903ff02012-08-28 12:52:22 -0400732 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700733 return error;
Al Viro9f45f5b2014-10-31 17:44:57 -0400734 audit_file(f.file);
Miklos Szeredi6742cee2018-07-18 15:44:43 +0200735 error = mnt_want_write_file(f.file);
Dave Hansen18f335a2008-02-15 14:37:38 -0800736 if (!error) {
Al Viro9f45f5b2014-10-31 17:44:57 -0400737 error = removexattr(f.file->f_path.dentry, name);
Miklos Szeredi6742cee2018-07-18 15:44:43 +0200738 mnt_drop_write_file(f.file);
Dave Hansen18f335a2008-02-15 14:37:38 -0800739 }
Al Viro2903ff02012-08-28 12:52:22 -0400740 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700741 return error;
742}
743
Linus Torvalds1da177e2005-04-16 15:20:36 -0700744/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700745 * Combine the results of the list() operation from every xattr_handler in the
746 * list.
747 */
748ssize_t
749generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
750{
Stephen Hemmingerbb435452010-05-13 17:53:14 -0700751 const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700752 unsigned int size = 0;
753
754 if (!buffer) {
Christoph Hellwig431547b2009-11-13 09:52:56 +0000755 for_each_xattr_handler(handlers, handler) {
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100756 if (!handler->name ||
757 (handler->list && !handler->list(dentry)))
Andreas Gruenbacherc4803c42015-12-02 14:44:41 +0100758 continue;
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100759 size += strlen(handler->name) + 1;
Christoph Hellwig431547b2009-11-13 09:52:56 +0000760 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700761 } else {
762 char *buf = buffer;
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100763 size_t len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764
765 for_each_xattr_handler(handlers, handler) {
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100766 if (!handler->name ||
767 (handler->list && !handler->list(dentry)))
Andreas Gruenbacherc4803c42015-12-02 14:44:41 +0100768 continue;
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100769 len = strlen(handler->name);
770 if (len + 1 > buffer_size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700771 return -ERANGE;
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100772 memcpy(buf, handler->name, len + 1);
773 buf += len + 1;
774 buffer_size -= len + 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775 }
776 size = buf - buffer;
777 }
778 return size;
779}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780EXPORT_SYMBOL(generic_listxattr);
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400781
Andreas Gruenbachere409de92015-10-04 19:18:52 +0200782/**
783 * xattr_full_name - Compute full attribute name from suffix
784 *
785 * @handler: handler of the xattr_handler operation
786 * @name: name passed to the xattr_handler operation
787 *
788 * The get and set xattr handler operations are called with the remainder of
789 * the attribute name after skipping the handler's prefix: for example, "foo"
790 * is passed to the get operation of a handler with prefix "user." to get
791 * attribute "user.foo". The full name is still "there" in the name though.
792 *
793 * Note: the list xattr handler operation when called from the vfs is passed a
794 * NULL name; some file systems use this operation internally, with varying
795 * semantics.
796 */
797const char *xattr_full_name(const struct xattr_handler *handler,
798 const char *name)
799{
Andreas Gruenbacher98e9cb52015-12-02 14:44:36 +0100800 size_t prefix_len = strlen(xattr_prefix(handler));
Andreas Gruenbachere409de92015-10-04 19:18:52 +0200801
802 return name - prefix_len;
803}
804EXPORT_SYMBOL(xattr_full_name);
805
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400806/*
807 * Allocate new xattr and copy in the value; but leave the name to callers.
808 */
809struct simple_xattr *simple_xattr_alloc(const void *value, size_t size)
810{
811 struct simple_xattr *new_xattr;
812 size_t len;
813
814 /* wrap around? */
815 len = sizeof(*new_xattr) + size;
Hugh Dickins4e66d442014-07-23 14:00:17 -0700816 if (len < sizeof(*new_xattr))
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400817 return NULL;
818
819 new_xattr = kmalloc(len, GFP_KERNEL);
820 if (!new_xattr)
821 return NULL;
822
823 new_xattr->size = size;
824 memcpy(new_xattr->value, value, size);
825 return new_xattr;
826}
827
828/*
829 * xattr GET operation for in-memory/pseudo filesystems
830 */
831int simple_xattr_get(struct simple_xattrs *xattrs, const char *name,
832 void *buffer, size_t size)
833{
834 struct simple_xattr *xattr;
835 int ret = -ENODATA;
836
837 spin_lock(&xattrs->lock);
838 list_for_each_entry(xattr, &xattrs->head, list) {
839 if (strcmp(name, xattr->name))
840 continue;
841
842 ret = xattr->size;
843 if (buffer) {
844 if (size < xattr->size)
845 ret = -ERANGE;
846 else
847 memcpy(buffer, xattr->value, xattr->size);
848 }
849 break;
850 }
851 spin_unlock(&xattrs->lock);
852 return ret;
853}
854
Andreas Gruenbacheraa7c5242015-12-02 14:44:38 +0100855/**
856 * simple_xattr_set - xattr SET operation for in-memory/pseudo filesystems
857 * @xattrs: target simple_xattr list
858 * @name: name of the extended attribute
859 * @value: value of the xattr. If %NULL, will remove the attribute.
860 * @size: size of the new xattr
861 * @flags: %XATTR_{CREATE|REPLACE}
862 *
863 * %XATTR_CREATE is set, the xattr shouldn't exist already; otherwise fails
864 * with -EEXIST. If %XATTR_REPLACE is set, the xattr should exist;
865 * otherwise, fails with -ENODATA.
866 *
867 * Returns 0 on success, -errno on failure.
868 */
869int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,
870 const void *value, size_t size, int flags)
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400871{
872 struct simple_xattr *xattr;
David Rientjes43385842012-10-17 20:41:15 -0700873 struct simple_xattr *new_xattr = NULL;
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400874 int err = 0;
875
876 /* value == NULL means remove */
877 if (value) {
878 new_xattr = simple_xattr_alloc(value, size);
879 if (!new_xattr)
880 return -ENOMEM;
881
882 new_xattr->name = kstrdup(name, GFP_KERNEL);
883 if (!new_xattr->name) {
884 kfree(new_xattr);
885 return -ENOMEM;
886 }
887 }
888
889 spin_lock(&xattrs->lock);
890 list_for_each_entry(xattr, &xattrs->head, list) {
891 if (!strcmp(name, xattr->name)) {
892 if (flags & XATTR_CREATE) {
893 xattr = new_xattr;
894 err = -EEXIST;
895 } else if (new_xattr) {
896 list_replace(&xattr->list, &new_xattr->list);
897 } else {
898 list_del(&xattr->list);
899 }
900 goto out;
901 }
902 }
903 if (flags & XATTR_REPLACE) {
904 xattr = new_xattr;
905 err = -ENODATA;
906 } else {
907 list_add(&new_xattr->list, &xattrs->head);
908 xattr = NULL;
909 }
910out:
911 spin_unlock(&xattrs->lock);
912 if (xattr) {
913 kfree(xattr->name);
914 kfree(xattr);
915 }
916 return err;
917
918}
919
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400920static bool xattr_is_trusted(const char *name)
921{
922 return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN);
923}
924
Andreas Gruenbacher786534b2015-12-02 14:44:39 +0100925static int xattr_list_one(char **buffer, ssize_t *remaining_size,
926 const char *name)
927{
928 size_t len = strlen(name) + 1;
929 if (*buffer) {
930 if (*remaining_size < len)
931 return -ERANGE;
932 memcpy(*buffer, name, len);
933 *buffer += len;
934 }
935 *remaining_size -= len;
936 return 0;
937}
938
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400939/*
940 * xattr LIST operation for in-memory/pseudo filesystems
941 */
Andreas Gruenbacher786534b2015-12-02 14:44:39 +0100942ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs,
943 char *buffer, size_t size)
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400944{
945 bool trusted = capable(CAP_SYS_ADMIN);
946 struct simple_xattr *xattr;
Andreas Gruenbacher786534b2015-12-02 14:44:39 +0100947 ssize_t remaining_size = size;
Mateusz Guzik0e9a7da2016-02-04 02:56:30 +0100948 int err = 0;
Andreas Gruenbacher786534b2015-12-02 14:44:39 +0100949
950#ifdef CONFIG_FS_POSIX_ACL
951 if (inode->i_acl) {
952 err = xattr_list_one(&buffer, &remaining_size,
953 XATTR_NAME_POSIX_ACL_ACCESS);
954 if (err)
955 return err;
956 }
957 if (inode->i_default_acl) {
958 err = xattr_list_one(&buffer, &remaining_size,
959 XATTR_NAME_POSIX_ACL_DEFAULT);
960 if (err)
961 return err;
962 }
963#endif
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400964
965 spin_lock(&xattrs->lock);
966 list_for_each_entry(xattr, &xattrs->head, list) {
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400967 /* skip "trusted." attributes for unprivileged callers */
968 if (!trusted && xattr_is_trusted(xattr->name))
969 continue;
970
Andreas Gruenbacher786534b2015-12-02 14:44:39 +0100971 err = xattr_list_one(&buffer, &remaining_size, xattr->name);
972 if (err)
Mateusz Guzik0e9a7da2016-02-04 02:56:30 +0100973 break;
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400974 }
975 spin_unlock(&xattrs->lock);
976
Mateusz Guzik0e9a7da2016-02-04 02:56:30 +0100977 return err ? err : size - remaining_size;
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400978}
979
Aristeu Rozanski48957682012-09-11 16:28:11 -0400980/*
981 * Adds an extended attribute to the list
982 */
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400983void simple_xattr_list_add(struct simple_xattrs *xattrs,
984 struct simple_xattr *new_xattr)
985{
986 spin_lock(&xattrs->lock);
987 list_add(&new_xattr->list, &xattrs->head);
988 spin_unlock(&xattrs->lock);
989}