blob: 7e3317cf4045523a7d0b17f102d51775808a8950 [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
231ssize_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:
252 security_release_secctx(buffer, len);
253out_noalloc:
254 return len;
255}
256EXPORT_SYMBOL_GPL(xattr_getsecurity);
257
Mimi Zohar1601fba2011-03-09 14:23:34 -0500258/*
259 * vfs_getxattr_alloc - allocate memory, if necessary, before calling getxattr
260 *
261 * Allocate memory, if not already allocated, or re-allocate correct size,
262 * before retrieving the extended attribute.
263 *
264 * Returns the result of alloc, if failed, or the getxattr operation.
265 */
266ssize_t
267vfs_getxattr_alloc(struct dentry *dentry, const char *name, char **xattr_value,
268 size_t xattr_size, gfp_t flags)
269{
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200270 const struct xattr_handler *handler;
Mimi Zohar1601fba2011-03-09 14:23:34 -0500271 struct inode *inode = dentry->d_inode;
272 char *value = *xattr_value;
273 int error;
274
275 error = xattr_permission(inode, name, MAY_READ);
276 if (error)
277 return error;
278
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200279 handler = xattr_resolve_name(inode, &name);
280 if (IS_ERR(handler))
281 return PTR_ERR(handler);
282 if (!handler->get)
Mimi Zohar1601fba2011-03-09 14:23:34 -0500283 return -EOPNOTSUPP;
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200284 error = handler->get(handler, dentry, inode, name, NULL, 0);
Mimi Zohar1601fba2011-03-09 14:23:34 -0500285 if (error < 0)
286 return error;
287
288 if (!value || (error > xattr_size)) {
289 value = krealloc(*xattr_value, error + 1, flags);
290 if (!value)
291 return -ENOMEM;
292 memset(value, 0, error + 1);
293 }
294
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200295 error = handler->get(handler, dentry, inode, name, value, error);
Mimi Zohar1601fba2011-03-09 14:23:34 -0500296 *xattr_value = value;
297 return error;
298}
299
David P. Quigley42492592008-02-04 22:29:39 -0800300ssize_t
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200301__vfs_getxattr(struct dentry *dentry, struct inode *inode, const char *name,
302 void *value, size_t size)
303{
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200304 const struct xattr_handler *handler;
305
306 handler = xattr_resolve_name(inode, &name);
307 if (IS_ERR(handler))
308 return PTR_ERR(handler);
309 if (!handler->get)
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200310 return -EOPNOTSUPP;
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200311 return handler->get(handler, dentry, inode, name, value, size);
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200312}
313EXPORT_SYMBOL(__vfs_getxattr);
314
315ssize_t
David Howells8f0cfa52008-04-29 00:59:41 -0700316vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size)
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800317{
318 struct inode *inode = dentry->d_inode;
319 int error;
320
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800321 error = xattr_permission(inode, name, MAY_READ);
322 if (error)
323 return error;
324
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800325 error = security_inode_getxattr(dentry, name);
326 if (error)
327 return error;
328
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800329 if (!strncmp(name, XATTR_SECURITY_PREFIX,
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800330 XATTR_SECURITY_PREFIX_LEN)) {
331 const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
David P. Quigley42492592008-02-04 22:29:39 -0800332 int ret = xattr_getsecurity(inode, suffix, value, size);
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800333 /*
334 * Only overwrite the return value if a security module
335 * is actually active.
336 */
David P. Quigley4bea5802008-02-04 22:29:40 -0800337 if (ret == -EOPNOTSUPP)
338 goto nolsm;
339 return ret;
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800340 }
David P. Quigley4bea5802008-02-04 22:29:40 -0800341nolsm:
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200342 return __vfs_getxattr(dentry, inode, name, value, size);
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800343}
344EXPORT_SYMBOL_GPL(vfs_getxattr);
345
Bill Nottingham659564c2006-10-09 16:10:48 -0400346ssize_t
Andreas Gruenbacherbf3ee712016-09-29 17:48:43 +0200347vfs_listxattr(struct dentry *dentry, char *list, size_t size)
Bill Nottingham659564c2006-10-09 16:10:48 -0400348{
Andreas Gruenbacherbf3ee712016-09-29 17:48:43 +0200349 struct inode *inode = d_inode(dentry);
Bill Nottingham659564c2006-10-09 16:10:48 -0400350 ssize_t error;
351
Andreas Gruenbacherbf3ee712016-09-29 17:48:43 +0200352 error = security_inode_listxattr(dentry);
Bill Nottingham659564c2006-10-09 16:10:48 -0400353 if (error)
354 return error;
Andreas Gruenbacherbf3ee712016-09-29 17:48:43 +0200355 if (inode->i_op->listxattr && (inode->i_opflags & IOP_XATTR)) {
356 error = -EOPNOTSUPP;
357 error = inode->i_op->listxattr(dentry, list, size);
Bill Nottingham659564c2006-10-09 16:10:48 -0400358 } else {
Andreas Gruenbacherbf3ee712016-09-29 17:48:43 +0200359 error = security_inode_listsecurity(inode, list, size);
Bill Nottingham659564c2006-10-09 16:10:48 -0400360 if (size && error > size)
361 error = -ERANGE;
362 }
363 return error;
364}
365EXPORT_SYMBOL_GPL(vfs_listxattr);
366
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800367int
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200368__vfs_removexattr(struct dentry *dentry, const char *name)
369{
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200370 struct inode *inode = d_inode(dentry);
371 const struct xattr_handler *handler;
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200372
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200373 handler = xattr_resolve_name(inode, &name);
374 if (IS_ERR(handler))
375 return PTR_ERR(handler);
376 if (!handler->set)
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200377 return -EOPNOTSUPP;
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200378 return handler->set(handler, dentry, inode, name, NULL, 0, XATTR_REPLACE);
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200379}
380EXPORT_SYMBOL(__vfs_removexattr);
381
382int
David Howells8f0cfa52008-04-29 00:59:41 -0700383vfs_removexattr(struct dentry *dentry, const char *name)
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800384{
385 struct inode *inode = dentry->d_inode;
386 int error;
387
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800388 error = xattr_permission(inode, name, MAY_WRITE);
389 if (error)
390 return error;
391
Al Viro59551022016-01-22 15:40:57 -0500392 inode_lock(inode);
Mimi Zohar2ab51f32011-03-23 17:23:06 -0400393 error = security_inode_removexattr(dentry, name);
Dmitry Kasatkin7c51bb002014-11-20 16:31:01 +0200394 if (error)
395 goto out;
Mimi Zohar2ab51f32011-03-23 17:23:06 -0400396
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200397 error = __vfs_removexattr(dentry, name);
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800398
Mimi Zoharc7b87de2011-03-09 14:39:18 -0500399 if (!error) {
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800400 fsnotify_xattr(dentry);
Mimi Zoharc7b87de2011-03-09 14:39:18 -0500401 evm_inode_post_removexattr(dentry, name);
402 }
Dmitry Kasatkin7c51bb002014-11-20 16:31:01 +0200403
404out:
Al Viro59551022016-01-22 15:40:57 -0500405 inode_unlock(inode);
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800406 return error;
407}
408EXPORT_SYMBOL_GPL(vfs_removexattr);
409
410
Linus Torvalds1da177e2005-04-16 15:20:36 -0700411/*
412 * Extended attribute SET operations
413 */
414static long
David Howells8f0cfa52008-04-29 00:59:41 -0700415setxattr(struct dentry *d, const char __user *name, const void __user *value,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416 size_t size, int flags)
417{
418 int error;
419 void *kvalue = NULL;
420 char kname[XATTR_NAME_MAX + 1];
421
422 if (flags & ~(XATTR_CREATE|XATTR_REPLACE))
423 return -EINVAL;
424
425 error = strncpy_from_user(kname, name, sizeof(kname));
426 if (error == 0 || error == sizeof(kname))
427 error = -ERANGE;
428 if (error < 0)
429 return error;
430
431 if (size) {
432 if (size > XATTR_SIZE_MAX)
433 return -E2BIG;
Andrew Morton44c82492012-04-05 14:25:07 -0700434 kvalue = kmalloc(size, GFP_KERNEL | __GFP_NOWARN);
435 if (!kvalue) {
Richard Weinberger0b2a6f22016-01-02 23:09:47 +0100436 kvalue = vmalloc(size);
437 if (!kvalue)
Andrew Morton44c82492012-04-05 14:25:07 -0700438 return -ENOMEM;
Andrew Morton44c82492012-04-05 14:25:07 -0700439 }
440 if (copy_from_user(kvalue, value, size)) {
441 error = -EFAULT;
442 goto out;
443 }
Eric W. Biederman2f6f0652012-02-07 18:52:57 -0800444 if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
445 (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
446 posix_acl_fix_xattr_from_user(kvalue, size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447 }
448
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800449 error = vfs_setxattr(d, kname, kvalue, size, flags);
Andrew Morton44c82492012-04-05 14:25:07 -0700450out:
Richard Weinberger0b2a6f22016-01-02 23:09:47 +0100451 kvfree(kvalue);
452
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453 return error;
454}
455
Eric Biggers8cc43112014-10-12 11:59:58 -0500456static int path_setxattr(const char __user *pathname,
457 const char __user *name, const void __user *value,
458 size_t size, int flags, unsigned int lookup_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700459{
Al Viro2d8f3032008-07-22 09:59:21 -0400460 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461 int error;
Jeff Layton68f1bb82012-12-11 12:10:15 -0500462retry:
463 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 if (error)
465 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400466 error = mnt_want_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800467 if (!error) {
Al Viro2d8f3032008-07-22 09:59:21 -0400468 error = setxattr(path.dentry, name, value, size, flags);
469 mnt_drop_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800470 }
Al Viro2d8f3032008-07-22 09:59:21 -0400471 path_put(&path);
Jeff Layton68f1bb82012-12-11 12:10:15 -0500472 if (retry_estale(error, lookup_flags)) {
473 lookup_flags |= LOOKUP_REVAL;
474 goto retry;
475 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476 return error;
477}
478
Eric Biggers8cc43112014-10-12 11:59:58 -0500479SYSCALL_DEFINE5(setxattr, const char __user *, pathname,
480 const char __user *, name, const void __user *, value,
481 size_t, size, int, flags)
482{
483 return path_setxattr(pathname, name, value, size, flags, LOOKUP_FOLLOW);
484}
485
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100486SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname,
487 const char __user *, name, const void __user *, value,
488 size_t, size, int, flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489{
Eric Biggers8cc43112014-10-12 11:59:58 -0500490 return path_setxattr(pathname, name, value, size, flags, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491}
492
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100493SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
494 const void __user *,value, size_t, size, int, flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495{
Al Viro2903ff02012-08-28 12:52:22 -0400496 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497 int error = -EBADF;
498
Al Viro2903ff02012-08-28 12:52:22 -0400499 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500 return error;
Al Viro9f45f5b2014-10-31 17:44:57 -0400501 audit_file(f.file);
Al Viro2903ff02012-08-28 12:52:22 -0400502 error = mnt_want_write_file(f.file);
Dave Hansen18f335a2008-02-15 14:37:38 -0800503 if (!error) {
Al Viro9f45f5b2014-10-31 17:44:57 -0400504 error = setxattr(f.file->f_path.dentry, name, value, size, flags);
Al Viro2903ff02012-08-28 12:52:22 -0400505 mnt_drop_write_file(f.file);
Dave Hansen18f335a2008-02-15 14:37:38 -0800506 }
Al Viro2903ff02012-08-28 12:52:22 -0400507 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 return error;
509}
510
511/*
512 * Extended attribute GET operations
513 */
514static ssize_t
David Howells8f0cfa52008-04-29 00:59:41 -0700515getxattr(struct dentry *d, const char __user *name, void __user *value,
516 size_t size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700517{
518 ssize_t error;
519 void *kvalue = NULL;
520 char kname[XATTR_NAME_MAX + 1];
521
522 error = strncpy_from_user(kname, name, sizeof(kname));
523 if (error == 0 || error == sizeof(kname))
524 error = -ERANGE;
525 if (error < 0)
526 return error;
527
528 if (size) {
529 if (size > XATTR_SIZE_MAX)
530 size = XATTR_SIZE_MAX;
Sasha Levin779302e2012-07-30 14:39:13 -0700531 kvalue = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);
532 if (!kvalue) {
Richard Weinberger0b2a6f22016-01-02 23:09:47 +0100533 kvalue = vmalloc(size);
534 if (!kvalue)
Sasha Levin779302e2012-07-30 14:39:13 -0700535 return -ENOMEM;
Sasha Levin779302e2012-07-30 14:39:13 -0700536 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537 }
538
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800539 error = vfs_getxattr(d, kname, kvalue, size);
Stephen Smalleyf549d6c2005-09-03 15:55:18 -0700540 if (error > 0) {
Eric W. Biederman2f6f0652012-02-07 18:52:57 -0800541 if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
542 (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
543 posix_acl_fix_xattr_to_user(kvalue, size);
Stephen Smalleyf549d6c2005-09-03 15:55:18 -0700544 if (size && copy_to_user(value, kvalue, error))
545 error = -EFAULT;
546 } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) {
547 /* The file system tried to returned a value bigger
548 than XATTR_SIZE_MAX bytes. Not possible. */
549 error = -E2BIG;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700550 }
Richard Weinberger0b2a6f22016-01-02 23:09:47 +0100551
552 kvfree(kvalue);
553
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554 return error;
555}
556
Eric Biggers8cc43112014-10-12 11:59:58 -0500557static ssize_t path_getxattr(const char __user *pathname,
558 const char __user *name, void __user *value,
559 size_t size, unsigned int lookup_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560{
Al Viro2d8f3032008-07-22 09:59:21 -0400561 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562 ssize_t error;
Jeff Layton60e66b42012-12-11 12:10:16 -0500563retry:
564 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565 if (error)
566 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400567 error = getxattr(path.dentry, name, value, size);
568 path_put(&path);
Jeff Layton60e66b42012-12-11 12:10:16 -0500569 if (retry_estale(error, lookup_flags)) {
570 lookup_flags |= LOOKUP_REVAL;
571 goto retry;
572 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573 return error;
574}
575
Eric Biggers8cc43112014-10-12 11:59:58 -0500576SYSCALL_DEFINE4(getxattr, const char __user *, pathname,
577 const char __user *, name, void __user *, value, size_t, size)
578{
579 return path_getxattr(pathname, name, value, size, LOOKUP_FOLLOW);
580}
581
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100582SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname,
583 const char __user *, name, void __user *, value, size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584{
Eric Biggers8cc43112014-10-12 11:59:58 -0500585 return path_getxattr(pathname, name, value, size, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586}
587
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100588SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name,
589 void __user *, value, size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590{
Al Viro2903ff02012-08-28 12:52:22 -0400591 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700592 ssize_t error = -EBADF;
593
Al Viro2903ff02012-08-28 12:52:22 -0400594 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595 return error;
Al Viro9f45f5b2014-10-31 17:44:57 -0400596 audit_file(f.file);
Al Viro2903ff02012-08-28 12:52:22 -0400597 error = getxattr(f.file->f_path.dentry, name, value, size);
598 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700599 return error;
600}
601
602/*
603 * Extended attribute LIST operations
604 */
605static ssize_t
606listxattr(struct dentry *d, char __user *list, size_t size)
607{
608 ssize_t error;
609 char *klist = NULL;
610
611 if (size) {
612 if (size > XATTR_LIST_MAX)
613 size = XATTR_LIST_MAX;
Dave Jones703bf2d2012-04-05 14:25:06 -0700614 klist = kmalloc(size, __GFP_NOWARN | GFP_KERNEL);
Andrew Morton0d08d7b2012-04-05 14:25:07 -0700615 if (!klist) {
Richard Weinberger0b2a6f22016-01-02 23:09:47 +0100616 klist = vmalloc(size);
617 if (!klist)
Andrew Morton0d08d7b2012-04-05 14:25:07 -0700618 return -ENOMEM;
Andrew Morton0d08d7b2012-04-05 14:25:07 -0700619 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700620 }
621
Bill Nottingham659564c2006-10-09 16:10:48 -0400622 error = vfs_listxattr(d, klist, size);
Stephen Smalleyf549d6c2005-09-03 15:55:18 -0700623 if (error > 0) {
624 if (size && copy_to_user(list, klist, error))
625 error = -EFAULT;
626 } else if (error == -ERANGE && size >= XATTR_LIST_MAX) {
627 /* The file system tried to returned a list bigger
628 than XATTR_LIST_MAX bytes. Not possible. */
629 error = -E2BIG;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700630 }
Richard Weinberger0b2a6f22016-01-02 23:09:47 +0100631
632 kvfree(klist);
633
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634 return error;
635}
636
Eric Biggers8cc43112014-10-12 11:59:58 -0500637static ssize_t path_listxattr(const char __user *pathname, char __user *list,
638 size_t size, unsigned int lookup_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700639{
Al Viro2d8f3032008-07-22 09:59:21 -0400640 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641 ssize_t error;
Jeff Layton10a90cf2012-12-11 12:10:16 -0500642retry:
643 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700644 if (error)
645 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400646 error = listxattr(path.dentry, list, size);
647 path_put(&path);
Jeff Layton10a90cf2012-12-11 12:10:16 -0500648 if (retry_estale(error, lookup_flags)) {
649 lookup_flags |= LOOKUP_REVAL;
650 goto retry;
651 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700652 return error;
653}
654
Eric Biggers8cc43112014-10-12 11:59:58 -0500655SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list,
656 size_t, size)
657{
658 return path_listxattr(pathname, list, size, LOOKUP_FOLLOW);
659}
660
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100661SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list,
662 size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700663{
Eric Biggers8cc43112014-10-12 11:59:58 -0500664 return path_listxattr(pathname, list, size, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700665}
666
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100667SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668{
Al Viro2903ff02012-08-28 12:52:22 -0400669 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670 ssize_t error = -EBADF;
671
Al Viro2903ff02012-08-28 12:52:22 -0400672 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673 return error;
Al Viro9f45f5b2014-10-31 17:44:57 -0400674 audit_file(f.file);
Al Viro2903ff02012-08-28 12:52:22 -0400675 error = listxattr(f.file->f_path.dentry, list, size);
676 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700677 return error;
678}
679
680/*
681 * Extended attribute REMOVE operations
682 */
683static long
David Howells8f0cfa52008-04-29 00:59:41 -0700684removexattr(struct dentry *d, const char __user *name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700685{
686 int error;
687 char kname[XATTR_NAME_MAX + 1];
688
689 error = strncpy_from_user(kname, name, sizeof(kname));
690 if (error == 0 || error == sizeof(kname))
691 error = -ERANGE;
692 if (error < 0)
693 return error;
694
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800695 return vfs_removexattr(d, kname);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696}
697
Eric Biggers8cc43112014-10-12 11:59:58 -0500698static int path_removexattr(const char __user *pathname,
699 const char __user *name, unsigned int lookup_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700700{
Al Viro2d8f3032008-07-22 09:59:21 -0400701 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700702 int error;
Jeff Layton12f06212012-12-11 12:10:17 -0500703retry:
704 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705 if (error)
706 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400707 error = mnt_want_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800708 if (!error) {
Al Viro2d8f3032008-07-22 09:59:21 -0400709 error = removexattr(path.dentry, name);
710 mnt_drop_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800711 }
Al Viro2d8f3032008-07-22 09:59:21 -0400712 path_put(&path);
Jeff Layton12f06212012-12-11 12:10:17 -0500713 if (retry_estale(error, lookup_flags)) {
714 lookup_flags |= LOOKUP_REVAL;
715 goto retry;
716 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700717 return error;
718}
719
Eric Biggers8cc43112014-10-12 11:59:58 -0500720SYSCALL_DEFINE2(removexattr, const char __user *, pathname,
721 const char __user *, name)
722{
723 return path_removexattr(pathname, name, LOOKUP_FOLLOW);
724}
725
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100726SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname,
727 const char __user *, name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700728{
Eric Biggers8cc43112014-10-12 11:59:58 -0500729 return path_removexattr(pathname, name, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730}
731
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100732SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700733{
Al Viro2903ff02012-08-28 12:52:22 -0400734 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 int error = -EBADF;
736
Al Viro2903ff02012-08-28 12:52:22 -0400737 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700738 return error;
Al Viro9f45f5b2014-10-31 17:44:57 -0400739 audit_file(f.file);
Al Viro2903ff02012-08-28 12:52:22 -0400740 error = mnt_want_write_file(f.file);
Dave Hansen18f335a2008-02-15 14:37:38 -0800741 if (!error) {
Al Viro9f45f5b2014-10-31 17:44:57 -0400742 error = removexattr(f.file->f_path.dentry, name);
Al Viro2903ff02012-08-28 12:52:22 -0400743 mnt_drop_write_file(f.file);
Dave Hansen18f335a2008-02-15 14:37:38 -0800744 }
Al Viro2903ff02012-08-28 12:52:22 -0400745 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700746 return error;
747}
748
Linus Torvalds1da177e2005-04-16 15:20:36 -0700749/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750 * Combine the results of the list() operation from every xattr_handler in the
751 * list.
752 */
753ssize_t
754generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
755{
Stephen Hemmingerbb435452010-05-13 17:53:14 -0700756 const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700757 unsigned int size = 0;
758
759 if (!buffer) {
Christoph Hellwig431547b2009-11-13 09:52:56 +0000760 for_each_xattr_handler(handlers, handler) {
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100761 if (!handler->name ||
762 (handler->list && !handler->list(dentry)))
Andreas Gruenbacherc4803c42015-12-02 14:44:41 +0100763 continue;
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100764 size += strlen(handler->name) + 1;
Christoph Hellwig431547b2009-11-13 09:52:56 +0000765 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700766 } else {
767 char *buf = buffer;
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100768 size_t len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700769
770 for_each_xattr_handler(handlers, handler) {
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100771 if (!handler->name ||
772 (handler->list && !handler->list(dentry)))
Andreas Gruenbacherc4803c42015-12-02 14:44:41 +0100773 continue;
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100774 len = strlen(handler->name);
775 if (len + 1 > buffer_size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700776 return -ERANGE;
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100777 memcpy(buf, handler->name, len + 1);
778 buf += len + 1;
779 buffer_size -= len + 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780 }
781 size = buf - buffer;
782 }
783 return size;
784}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700785EXPORT_SYMBOL(generic_listxattr);
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400786
Andreas Gruenbachere409de92015-10-04 19:18:52 +0200787/**
788 * xattr_full_name - Compute full attribute name from suffix
789 *
790 * @handler: handler of the xattr_handler operation
791 * @name: name passed to the xattr_handler operation
792 *
793 * The get and set xattr handler operations are called with the remainder of
794 * the attribute name after skipping the handler's prefix: for example, "foo"
795 * is passed to the get operation of a handler with prefix "user." to get
796 * attribute "user.foo". The full name is still "there" in the name though.
797 *
798 * Note: the list xattr handler operation when called from the vfs is passed a
799 * NULL name; some file systems use this operation internally, with varying
800 * semantics.
801 */
802const char *xattr_full_name(const struct xattr_handler *handler,
803 const char *name)
804{
Andreas Gruenbacher98e9cb52015-12-02 14:44:36 +0100805 size_t prefix_len = strlen(xattr_prefix(handler));
Andreas Gruenbachere409de92015-10-04 19:18:52 +0200806
807 return name - prefix_len;
808}
809EXPORT_SYMBOL(xattr_full_name);
810
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400811/*
812 * Allocate new xattr and copy in the value; but leave the name to callers.
813 */
814struct simple_xattr *simple_xattr_alloc(const void *value, size_t size)
815{
816 struct simple_xattr *new_xattr;
817 size_t len;
818
819 /* wrap around? */
820 len = sizeof(*new_xattr) + size;
Hugh Dickins4e66d442014-07-23 14:00:17 -0700821 if (len < sizeof(*new_xattr))
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400822 return NULL;
823
824 new_xattr = kmalloc(len, GFP_KERNEL);
825 if (!new_xattr)
826 return NULL;
827
828 new_xattr->size = size;
829 memcpy(new_xattr->value, value, size);
830 return new_xattr;
831}
832
833/*
834 * xattr GET operation for in-memory/pseudo filesystems
835 */
836int simple_xattr_get(struct simple_xattrs *xattrs, const char *name,
837 void *buffer, size_t size)
838{
839 struct simple_xattr *xattr;
840 int ret = -ENODATA;
841
842 spin_lock(&xattrs->lock);
843 list_for_each_entry(xattr, &xattrs->head, list) {
844 if (strcmp(name, xattr->name))
845 continue;
846
847 ret = xattr->size;
848 if (buffer) {
849 if (size < xattr->size)
850 ret = -ERANGE;
851 else
852 memcpy(buffer, xattr->value, xattr->size);
853 }
854 break;
855 }
856 spin_unlock(&xattrs->lock);
857 return ret;
858}
859
Andreas Gruenbacheraa7c5242015-12-02 14:44:38 +0100860/**
861 * simple_xattr_set - xattr SET operation for in-memory/pseudo filesystems
862 * @xattrs: target simple_xattr list
863 * @name: name of the extended attribute
864 * @value: value of the xattr. If %NULL, will remove the attribute.
865 * @size: size of the new xattr
866 * @flags: %XATTR_{CREATE|REPLACE}
867 *
868 * %XATTR_CREATE is set, the xattr shouldn't exist already; otherwise fails
869 * with -EEXIST. If %XATTR_REPLACE is set, the xattr should exist;
870 * otherwise, fails with -ENODATA.
871 *
872 * Returns 0 on success, -errno on failure.
873 */
874int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,
875 const void *value, size_t size, int flags)
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400876{
877 struct simple_xattr *xattr;
David Rientjes43385842012-10-17 20:41:15 -0700878 struct simple_xattr *new_xattr = NULL;
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400879 int err = 0;
880
881 /* value == NULL means remove */
882 if (value) {
883 new_xattr = simple_xattr_alloc(value, size);
884 if (!new_xattr)
885 return -ENOMEM;
886
887 new_xattr->name = kstrdup(name, GFP_KERNEL);
888 if (!new_xattr->name) {
889 kfree(new_xattr);
890 return -ENOMEM;
891 }
892 }
893
894 spin_lock(&xattrs->lock);
895 list_for_each_entry(xattr, &xattrs->head, list) {
896 if (!strcmp(name, xattr->name)) {
897 if (flags & XATTR_CREATE) {
898 xattr = new_xattr;
899 err = -EEXIST;
900 } else if (new_xattr) {
901 list_replace(&xattr->list, &new_xattr->list);
902 } else {
903 list_del(&xattr->list);
904 }
905 goto out;
906 }
907 }
908 if (flags & XATTR_REPLACE) {
909 xattr = new_xattr;
910 err = -ENODATA;
911 } else {
912 list_add(&new_xattr->list, &xattrs->head);
913 xattr = NULL;
914 }
915out:
916 spin_unlock(&xattrs->lock);
917 if (xattr) {
918 kfree(xattr->name);
919 kfree(xattr);
920 }
921 return err;
922
923}
924
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400925static bool xattr_is_trusted(const char *name)
926{
927 return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN);
928}
929
Andreas Gruenbacher786534b2015-12-02 14:44:39 +0100930static int xattr_list_one(char **buffer, ssize_t *remaining_size,
931 const char *name)
932{
933 size_t len = strlen(name) + 1;
934 if (*buffer) {
935 if (*remaining_size < len)
936 return -ERANGE;
937 memcpy(*buffer, name, len);
938 *buffer += len;
939 }
940 *remaining_size -= len;
941 return 0;
942}
943
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400944/*
945 * xattr LIST operation for in-memory/pseudo filesystems
946 */
Andreas Gruenbacher786534b2015-12-02 14:44:39 +0100947ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs,
948 char *buffer, size_t size)
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400949{
950 bool trusted = capable(CAP_SYS_ADMIN);
951 struct simple_xattr *xattr;
Andreas Gruenbacher786534b2015-12-02 14:44:39 +0100952 ssize_t remaining_size = size;
Mateusz Guzik0e9a7da2016-02-04 02:56:30 +0100953 int err = 0;
Andreas Gruenbacher786534b2015-12-02 14:44:39 +0100954
955#ifdef CONFIG_FS_POSIX_ACL
956 if (inode->i_acl) {
957 err = xattr_list_one(&buffer, &remaining_size,
958 XATTR_NAME_POSIX_ACL_ACCESS);
959 if (err)
960 return err;
961 }
962 if (inode->i_default_acl) {
963 err = xattr_list_one(&buffer, &remaining_size,
964 XATTR_NAME_POSIX_ACL_DEFAULT);
965 if (err)
966 return err;
967 }
968#endif
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400969
970 spin_lock(&xattrs->lock);
971 list_for_each_entry(xattr, &xattrs->head, list) {
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400972 /* skip "trusted." attributes for unprivileged callers */
973 if (!trusted && xattr_is_trusted(xattr->name))
974 continue;
975
Andreas Gruenbacher786534b2015-12-02 14:44:39 +0100976 err = xattr_list_one(&buffer, &remaining_size, xattr->name);
977 if (err)
Mateusz Guzik0e9a7da2016-02-04 02:56:30 +0100978 break;
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400979 }
980 spin_unlock(&xattrs->lock);
981
Mateusz Guzik0e9a7da2016-02-04 02:56:30 +0100982 return err ? err : size - remaining_size;
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400983}
984
Aristeu Rozanski48957682012-09-11 16:28:11 -0400985/*
986 * Adds an extended attribute to the list
987 */
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400988void simple_xattr_list_add(struct simple_xattrs *xattrs,
989 struct simple_xattr *new_xattr)
990{
991 spin_lock(&xattrs->lock);
992 list_add(&new_xattr->list, &xattrs->head);
993 spin_unlock(&xattrs->lock);
994}