blob: 3368659c471e4f7dc8cd425738bccb7d5fec78a6 [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
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;
David P. Quigleyb1ab7e42009-09-03 14:25:56 -0400173 int error = -EOPNOTSUPP;
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 }
Andi Kleen69b45732011-05-28 08:25:51 -0700186 } else if (issec) {
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800187 const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
Andreas Gruenbacher5f6e59a2016-09-29 17:48:40 +0200188
189 if (unlikely(is_bad_inode(inode)))
190 return -EIO;
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800191 error = security_inode_setsecurity(inode, suffix, value,
192 size, flags);
193 if (!error)
194 fsnotify_xattr(dentry);
195 }
David P. Quigleyb1ab7e42009-09-03 14:25:56 -0400196
197 return error;
198}
199
200
201int
202vfs_setxattr(struct dentry *dentry, const char *name, const void *value,
203 size_t size, int flags)
204{
205 struct inode *inode = dentry->d_inode;
206 int error;
207
208 error = xattr_permission(inode, name, MAY_WRITE);
209 if (error)
210 return error;
211
Al Viro59551022016-01-22 15:40:57 -0500212 inode_lock(inode);
David P. Quigleyb1ab7e42009-09-03 14:25:56 -0400213 error = security_inode_setxattr(dentry, name, value, size, flags);
214 if (error)
215 goto out;
216
217 error = __vfs_setxattr_noperm(dentry, name, value, size, flags);
218
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800219out:
Al Viro59551022016-01-22 15:40:57 -0500220 inode_unlock(inode);
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800221 return error;
222}
223EXPORT_SYMBOL_GPL(vfs_setxattr);
224
225ssize_t
David P. Quigley42492592008-02-04 22:29:39 -0800226xattr_getsecurity(struct inode *inode, const char *name, void *value,
227 size_t size)
228{
229 void *buffer = NULL;
230 ssize_t len;
231
232 if (!value || !size) {
233 len = security_inode_getsecurity(inode, name, &buffer, false);
234 goto out_noalloc;
235 }
236
237 len = security_inode_getsecurity(inode, name, &buffer, true);
238 if (len < 0)
239 return len;
240 if (size < len) {
241 len = -ERANGE;
242 goto out;
243 }
244 memcpy(value, buffer, len);
245out:
246 security_release_secctx(buffer, len);
247out_noalloc:
248 return len;
249}
250EXPORT_SYMBOL_GPL(xattr_getsecurity);
251
Mimi Zohar1601fba2011-03-09 14:23:34 -0500252/*
253 * vfs_getxattr_alloc - allocate memory, if necessary, before calling getxattr
254 *
255 * Allocate memory, if not already allocated, or re-allocate correct size,
256 * before retrieving the extended attribute.
257 *
258 * Returns the result of alloc, if failed, or the getxattr operation.
259 */
260ssize_t
261vfs_getxattr_alloc(struct dentry *dentry, const char *name, char **xattr_value,
262 size_t xattr_size, gfp_t flags)
263{
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200264 const struct xattr_handler *handler;
Mimi Zohar1601fba2011-03-09 14:23:34 -0500265 struct inode *inode = dentry->d_inode;
266 char *value = *xattr_value;
267 int error;
268
269 error = xattr_permission(inode, name, MAY_READ);
270 if (error)
271 return error;
272
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200273 handler = xattr_resolve_name(inode, &name);
274 if (IS_ERR(handler))
275 return PTR_ERR(handler);
276 if (!handler->get)
Mimi Zohar1601fba2011-03-09 14:23:34 -0500277 return -EOPNOTSUPP;
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200278 error = handler->get(handler, dentry, inode, name, NULL, 0);
Mimi Zohar1601fba2011-03-09 14:23:34 -0500279 if (error < 0)
280 return error;
281
282 if (!value || (error > xattr_size)) {
283 value = krealloc(*xattr_value, error + 1, flags);
284 if (!value)
285 return -ENOMEM;
286 memset(value, 0, error + 1);
287 }
288
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200289 error = handler->get(handler, dentry, inode, name, value, error);
Mimi Zohar1601fba2011-03-09 14:23:34 -0500290 *xattr_value = value;
291 return error;
292}
293
David P. Quigley42492592008-02-04 22:29:39 -0800294ssize_t
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200295__vfs_getxattr(struct dentry *dentry, struct inode *inode, const char *name,
296 void *value, size_t size)
297{
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200298 const struct xattr_handler *handler;
299
300 handler = xattr_resolve_name(inode, &name);
301 if (IS_ERR(handler))
302 return PTR_ERR(handler);
303 if (!handler->get)
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200304 return -EOPNOTSUPP;
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200305 return handler->get(handler, dentry, inode, name, value, size);
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200306}
307EXPORT_SYMBOL(__vfs_getxattr);
308
309ssize_t
David Howells8f0cfa52008-04-29 00:59:41 -0700310vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size)
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800311{
312 struct inode *inode = dentry->d_inode;
313 int error;
314
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800315 error = xattr_permission(inode, name, MAY_READ);
316 if (error)
317 return error;
318
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800319 error = security_inode_getxattr(dentry, name);
320 if (error)
321 return error;
322
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800323 if (!strncmp(name, XATTR_SECURITY_PREFIX,
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800324 XATTR_SECURITY_PREFIX_LEN)) {
325 const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
David P. Quigley42492592008-02-04 22:29:39 -0800326 int ret = xattr_getsecurity(inode, suffix, value, size);
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800327 /*
328 * Only overwrite the return value if a security module
329 * is actually active.
330 */
David P. Quigley4bea5802008-02-04 22:29:40 -0800331 if (ret == -EOPNOTSUPP)
332 goto nolsm;
333 return ret;
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800334 }
David P. Quigley4bea5802008-02-04 22:29:40 -0800335nolsm:
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200336 return __vfs_getxattr(dentry, inode, name, value, size);
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800337}
338EXPORT_SYMBOL_GPL(vfs_getxattr);
339
Bill Nottingham659564c2006-10-09 16:10:48 -0400340ssize_t
Andreas Gruenbacherbf3ee712016-09-29 17:48:43 +0200341vfs_listxattr(struct dentry *dentry, char *list, size_t size)
Bill Nottingham659564c2006-10-09 16:10:48 -0400342{
Andreas Gruenbacherbf3ee712016-09-29 17:48:43 +0200343 struct inode *inode = d_inode(dentry);
Bill Nottingham659564c2006-10-09 16:10:48 -0400344 ssize_t error;
345
Andreas Gruenbacherbf3ee712016-09-29 17:48:43 +0200346 error = security_inode_listxattr(dentry);
Bill Nottingham659564c2006-10-09 16:10:48 -0400347 if (error)
348 return error;
Andreas Gruenbacherbf3ee712016-09-29 17:48:43 +0200349 if (inode->i_op->listxattr && (inode->i_opflags & IOP_XATTR)) {
350 error = -EOPNOTSUPP;
351 error = inode->i_op->listxattr(dentry, list, size);
Bill Nottingham659564c2006-10-09 16:10:48 -0400352 } else {
Andreas Gruenbacherbf3ee712016-09-29 17:48:43 +0200353 error = security_inode_listsecurity(inode, list, size);
Bill Nottingham659564c2006-10-09 16:10:48 -0400354 if (size && error > size)
355 error = -ERANGE;
356 }
357 return error;
358}
359EXPORT_SYMBOL_GPL(vfs_listxattr);
360
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800361int
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200362__vfs_removexattr(struct dentry *dentry, const char *name)
363{
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200364 struct inode *inode = d_inode(dentry);
365 const struct xattr_handler *handler;
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200366
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200367 handler = xattr_resolve_name(inode, &name);
368 if (IS_ERR(handler))
369 return PTR_ERR(handler);
370 if (!handler->set)
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200371 return -EOPNOTSUPP;
Andreas Gruenbacher6c6ef9f2016-09-29 17:48:44 +0200372 return handler->set(handler, dentry, inode, name, NULL, 0, XATTR_REPLACE);
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200373}
374EXPORT_SYMBOL(__vfs_removexattr);
375
376int
David Howells8f0cfa52008-04-29 00:59:41 -0700377vfs_removexattr(struct dentry *dentry, const char *name)
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800378{
379 struct inode *inode = dentry->d_inode;
380 int error;
381
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800382 error = xattr_permission(inode, name, MAY_WRITE);
383 if (error)
384 return error;
385
Al Viro59551022016-01-22 15:40:57 -0500386 inode_lock(inode);
Mimi Zohar2ab51f32011-03-23 17:23:06 -0400387 error = security_inode_removexattr(dentry, name);
Dmitry Kasatkin7c51bb02014-11-20 16:31:01 +0200388 if (error)
389 goto out;
Mimi Zohar2ab51f32011-03-23 17:23:06 -0400390
Andreas Gruenbacher5d6c3192016-09-29 17:48:42 +0200391 error = __vfs_removexattr(dentry, name);
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800392
Mimi Zoharc7b87de2011-03-09 14:39:18 -0500393 if (!error) {
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800394 fsnotify_xattr(dentry);
Mimi Zoharc7b87de2011-03-09 14:39:18 -0500395 evm_inode_post_removexattr(dentry, name);
396 }
Dmitry Kasatkin7c51bb02014-11-20 16:31:01 +0200397
398out:
Al Viro59551022016-01-22 15:40:57 -0500399 inode_unlock(inode);
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800400 return error;
401}
402EXPORT_SYMBOL_GPL(vfs_removexattr);
403
404
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405/*
406 * Extended attribute SET operations
407 */
408static long
David Howells8f0cfa52008-04-29 00:59:41 -0700409setxattr(struct dentry *d, const char __user *name, const void __user *value,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700410 size_t size, int flags)
411{
412 int error;
413 void *kvalue = NULL;
414 char kname[XATTR_NAME_MAX + 1];
415
416 if (flags & ~(XATTR_CREATE|XATTR_REPLACE))
417 return -EINVAL;
418
419 error = strncpy_from_user(kname, name, sizeof(kname));
420 if (error == 0 || error == sizeof(kname))
421 error = -ERANGE;
422 if (error < 0)
423 return error;
424
425 if (size) {
426 if (size > XATTR_SIZE_MAX)
427 return -E2BIG;
Andrew Morton44c82492012-04-05 14:25:07 -0700428 kvalue = kmalloc(size, GFP_KERNEL | __GFP_NOWARN);
429 if (!kvalue) {
Richard Weinberger0b2a6f22016-01-02 23:09:47 +0100430 kvalue = vmalloc(size);
431 if (!kvalue)
Andrew Morton44c82492012-04-05 14:25:07 -0700432 return -ENOMEM;
Andrew Morton44c82492012-04-05 14:25:07 -0700433 }
434 if (copy_from_user(kvalue, value, size)) {
435 error = -EFAULT;
436 goto out;
437 }
Eric W. Biederman2f6f0652012-02-07 18:52:57 -0800438 if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
439 (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
440 posix_acl_fix_xattr_from_user(kvalue, size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700441 }
442
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800443 error = vfs_setxattr(d, kname, kvalue, size, flags);
Andrew Morton44c82492012-04-05 14:25:07 -0700444out:
Richard Weinberger0b2a6f22016-01-02 23:09:47 +0100445 kvfree(kvalue);
446
Linus Torvalds1da177e2005-04-16 15:20:36 -0700447 return error;
448}
449
Eric Biggers8cc43112014-10-12 11:59:58 -0500450static int path_setxattr(const char __user *pathname,
451 const char __user *name, const void __user *value,
452 size_t size, int flags, unsigned int lookup_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453{
Al Viro2d8f3032008-07-22 09:59:21 -0400454 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455 int error;
Jeff Layton68f1bb82012-12-11 12:10:15 -0500456retry:
457 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458 if (error)
459 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400460 error = mnt_want_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800461 if (!error) {
Al Viro2d8f3032008-07-22 09:59:21 -0400462 error = setxattr(path.dentry, name, value, size, flags);
463 mnt_drop_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800464 }
Al Viro2d8f3032008-07-22 09:59:21 -0400465 path_put(&path);
Jeff Layton68f1bb82012-12-11 12:10:15 -0500466 if (retry_estale(error, lookup_flags)) {
467 lookup_flags |= LOOKUP_REVAL;
468 goto retry;
469 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470 return error;
471}
472
Eric Biggers8cc43112014-10-12 11:59:58 -0500473SYSCALL_DEFINE5(setxattr, const char __user *, pathname,
474 const char __user *, name, const void __user *, value,
475 size_t, size, int, flags)
476{
477 return path_setxattr(pathname, name, value, size, flags, LOOKUP_FOLLOW);
478}
479
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100480SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname,
481 const char __user *, name, const void __user *, value,
482 size_t, size, int, flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483{
Eric Biggers8cc43112014-10-12 11:59:58 -0500484 return path_setxattr(pathname, name, value, size, flags, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485}
486
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100487SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
488 const void __user *,value, size_t, size, int, flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489{
Al Viro2903ff02012-08-28 12:52:22 -0400490 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491 int error = -EBADF;
492
Al Viro2903ff02012-08-28 12:52:22 -0400493 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700494 return error;
Al Viro9f45f5b2014-10-31 17:44:57 -0400495 audit_file(f.file);
Al Viro2903ff02012-08-28 12:52:22 -0400496 error = mnt_want_write_file(f.file);
Dave Hansen18f335a2008-02-15 14:37:38 -0800497 if (!error) {
Al Viro9f45f5b2014-10-31 17:44:57 -0400498 error = setxattr(f.file->f_path.dentry, name, value, size, flags);
Al Viro2903ff02012-08-28 12:52:22 -0400499 mnt_drop_write_file(f.file);
Dave Hansen18f335a2008-02-15 14:37:38 -0800500 }
Al Viro2903ff02012-08-28 12:52:22 -0400501 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700502 return error;
503}
504
505/*
506 * Extended attribute GET operations
507 */
508static ssize_t
David Howells8f0cfa52008-04-29 00:59:41 -0700509getxattr(struct dentry *d, const char __user *name, void __user *value,
510 size_t size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700511{
512 ssize_t error;
513 void *kvalue = NULL;
514 char kname[XATTR_NAME_MAX + 1];
515
516 error = strncpy_from_user(kname, name, sizeof(kname));
517 if (error == 0 || error == sizeof(kname))
518 error = -ERANGE;
519 if (error < 0)
520 return error;
521
522 if (size) {
523 if (size > XATTR_SIZE_MAX)
524 size = XATTR_SIZE_MAX;
Sasha Levin779302e2012-07-30 14:39:13 -0700525 kvalue = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);
526 if (!kvalue) {
Richard Weinberger0b2a6f22016-01-02 23:09:47 +0100527 kvalue = vmalloc(size);
528 if (!kvalue)
Sasha Levin779302e2012-07-30 14:39:13 -0700529 return -ENOMEM;
Sasha Levin779302e2012-07-30 14:39:13 -0700530 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531 }
532
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800533 error = vfs_getxattr(d, kname, kvalue, size);
Stephen Smalleyf549d6c2005-09-03 15:55:18 -0700534 if (error > 0) {
Eric W. Biederman2f6f0652012-02-07 18:52:57 -0800535 if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
536 (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
537 posix_acl_fix_xattr_to_user(kvalue, size);
Stephen Smalleyf549d6c2005-09-03 15:55:18 -0700538 if (size && copy_to_user(value, kvalue, error))
539 error = -EFAULT;
540 } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) {
541 /* The file system tried to returned a value bigger
542 than XATTR_SIZE_MAX bytes. Not possible. */
543 error = -E2BIG;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700544 }
Richard Weinberger0b2a6f22016-01-02 23:09:47 +0100545
546 kvfree(kvalue);
547
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548 return error;
549}
550
Eric Biggers8cc43112014-10-12 11:59:58 -0500551static ssize_t path_getxattr(const char __user *pathname,
552 const char __user *name, void __user *value,
553 size_t size, unsigned int lookup_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700554{
Al Viro2d8f3032008-07-22 09:59:21 -0400555 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556 ssize_t error;
Jeff Layton60e66b42012-12-11 12:10:16 -0500557retry:
558 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559 if (error)
560 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400561 error = getxattr(path.dentry, name, value, size);
562 path_put(&path);
Jeff Layton60e66b42012-12-11 12:10:16 -0500563 if (retry_estale(error, lookup_flags)) {
564 lookup_flags |= LOOKUP_REVAL;
565 goto retry;
566 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567 return error;
568}
569
Eric Biggers8cc43112014-10-12 11:59:58 -0500570SYSCALL_DEFINE4(getxattr, const char __user *, pathname,
571 const char __user *, name, void __user *, value, size_t, size)
572{
573 return path_getxattr(pathname, name, value, size, LOOKUP_FOLLOW);
574}
575
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100576SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname,
577 const char __user *, name, void __user *, value, size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578{
Eric Biggers8cc43112014-10-12 11:59:58 -0500579 return path_getxattr(pathname, name, value, size, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580}
581
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100582SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name,
583 void __user *, value, size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584{
Al Viro2903ff02012-08-28 12:52:22 -0400585 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700586 ssize_t error = -EBADF;
587
Al Viro2903ff02012-08-28 12:52:22 -0400588 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589 return error;
Al Viro9f45f5b2014-10-31 17:44:57 -0400590 audit_file(f.file);
Al Viro2903ff02012-08-28 12:52:22 -0400591 error = getxattr(f.file->f_path.dentry, name, value, size);
592 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593 return error;
594}
595
596/*
597 * Extended attribute LIST operations
598 */
599static ssize_t
600listxattr(struct dentry *d, char __user *list, size_t size)
601{
602 ssize_t error;
603 char *klist = NULL;
604
605 if (size) {
606 if (size > XATTR_LIST_MAX)
607 size = XATTR_LIST_MAX;
Dave Jones703bf2d2012-04-05 14:25:06 -0700608 klist = kmalloc(size, __GFP_NOWARN | GFP_KERNEL);
Andrew Morton0d08d7b2012-04-05 14:25:07 -0700609 if (!klist) {
Richard Weinberger0b2a6f22016-01-02 23:09:47 +0100610 klist = vmalloc(size);
611 if (!klist)
Andrew Morton0d08d7b2012-04-05 14:25:07 -0700612 return -ENOMEM;
Andrew Morton0d08d7b2012-04-05 14:25:07 -0700613 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614 }
615
Bill Nottingham659564c2006-10-09 16:10:48 -0400616 error = vfs_listxattr(d, klist, size);
Stephen Smalleyf549d6c2005-09-03 15:55:18 -0700617 if (error > 0) {
618 if (size && copy_to_user(list, klist, error))
619 error = -EFAULT;
620 } else if (error == -ERANGE && size >= XATTR_LIST_MAX) {
621 /* The file system tried to returned a list bigger
622 than XATTR_LIST_MAX bytes. Not possible. */
623 error = -E2BIG;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624 }
Richard Weinberger0b2a6f22016-01-02 23:09:47 +0100625
626 kvfree(klist);
627
Linus Torvalds1da177e2005-04-16 15:20:36 -0700628 return error;
629}
630
Eric Biggers8cc43112014-10-12 11:59:58 -0500631static ssize_t path_listxattr(const char __user *pathname, char __user *list,
632 size_t size, unsigned int lookup_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700633{
Al Viro2d8f3032008-07-22 09:59:21 -0400634 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635 ssize_t error;
Jeff Layton10a90cf2012-12-11 12:10:16 -0500636retry:
637 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700638 if (error)
639 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400640 error = listxattr(path.dentry, list, size);
641 path_put(&path);
Jeff Layton10a90cf2012-12-11 12:10:16 -0500642 if (retry_estale(error, lookup_flags)) {
643 lookup_flags |= LOOKUP_REVAL;
644 goto retry;
645 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646 return error;
647}
648
Eric Biggers8cc43112014-10-12 11:59:58 -0500649SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list,
650 size_t, size)
651{
652 return path_listxattr(pathname, list, size, LOOKUP_FOLLOW);
653}
654
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100655SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list,
656 size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700657{
Eric Biggers8cc43112014-10-12 11:59:58 -0500658 return path_listxattr(pathname, list, size, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659}
660
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100661SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700662{
Al Viro2903ff02012-08-28 12:52:22 -0400663 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664 ssize_t error = -EBADF;
665
Al Viro2903ff02012-08-28 12:52:22 -0400666 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700667 return error;
Al Viro9f45f5b2014-10-31 17:44:57 -0400668 audit_file(f.file);
Al Viro2903ff02012-08-28 12:52:22 -0400669 error = listxattr(f.file->f_path.dentry, list, size);
670 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700671 return error;
672}
673
674/*
675 * Extended attribute REMOVE operations
676 */
677static long
David Howells8f0cfa52008-04-29 00:59:41 -0700678removexattr(struct dentry *d, const char __user *name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679{
680 int error;
681 char kname[XATTR_NAME_MAX + 1];
682
683 error = strncpy_from_user(kname, name, sizeof(kname));
684 if (error == 0 || error == sizeof(kname))
685 error = -ERANGE;
686 if (error < 0)
687 return error;
688
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800689 return vfs_removexattr(d, kname);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690}
691
Eric Biggers8cc43112014-10-12 11:59:58 -0500692static int path_removexattr(const char __user *pathname,
693 const char __user *name, unsigned int lookup_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700694{
Al Viro2d8f3032008-07-22 09:59:21 -0400695 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696 int error;
Jeff Layton12f06212012-12-11 12:10:17 -0500697retry:
698 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699 if (error)
700 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400701 error = mnt_want_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800702 if (!error) {
Al Viro2d8f3032008-07-22 09:59:21 -0400703 error = removexattr(path.dentry, name);
704 mnt_drop_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800705 }
Al Viro2d8f3032008-07-22 09:59:21 -0400706 path_put(&path);
Jeff Layton12f06212012-12-11 12:10:17 -0500707 if (retry_estale(error, lookup_flags)) {
708 lookup_flags |= LOOKUP_REVAL;
709 goto retry;
710 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700711 return error;
712}
713
Eric Biggers8cc43112014-10-12 11:59:58 -0500714SYSCALL_DEFINE2(removexattr, const char __user *, pathname,
715 const char __user *, name)
716{
717 return path_removexattr(pathname, name, LOOKUP_FOLLOW);
718}
719
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100720SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname,
721 const char __user *, name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722{
Eric Biggers8cc43112014-10-12 11:59:58 -0500723 return path_removexattr(pathname, name, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700724}
725
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100726SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727{
Al Viro2903ff02012-08-28 12:52:22 -0400728 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700729 int error = -EBADF;
730
Al Viro2903ff02012-08-28 12:52:22 -0400731 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700732 return error;
Al Viro9f45f5b2014-10-31 17:44:57 -0400733 audit_file(f.file);
Al Viro2903ff02012-08-28 12:52:22 -0400734 error = mnt_want_write_file(f.file);
Dave Hansen18f335a2008-02-15 14:37:38 -0800735 if (!error) {
Al Viro9f45f5b2014-10-31 17:44:57 -0400736 error = removexattr(f.file->f_path.dentry, name);
Al Viro2903ff02012-08-28 12:52:22 -0400737 mnt_drop_write_file(f.file);
Dave Hansen18f335a2008-02-15 14:37:38 -0800738 }
Al Viro2903ff02012-08-28 12:52:22 -0400739 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740 return error;
741}
742
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700744 * Combine the results of the list() operation from every xattr_handler in the
745 * list.
746 */
747ssize_t
748generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
749{
Stephen Hemmingerbb435452010-05-13 17:53:14 -0700750 const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700751 unsigned int size = 0;
752
753 if (!buffer) {
Christoph Hellwig431547b2009-11-13 09:52:56 +0000754 for_each_xattr_handler(handlers, handler) {
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100755 if (!handler->name ||
756 (handler->list && !handler->list(dentry)))
Andreas Gruenbacherc4803c42015-12-02 14:44:41 +0100757 continue;
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100758 size += strlen(handler->name) + 1;
Christoph Hellwig431547b2009-11-13 09:52:56 +0000759 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700760 } else {
761 char *buf = buffer;
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100762 size_t len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700763
764 for_each_xattr_handler(handlers, handler) {
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100765 if (!handler->name ||
766 (handler->list && !handler->list(dentry)))
Andreas Gruenbacherc4803c42015-12-02 14:44:41 +0100767 continue;
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100768 len = strlen(handler->name);
769 if (len + 1 > buffer_size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700770 return -ERANGE;
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100771 memcpy(buf, handler->name, len + 1);
772 buf += len + 1;
773 buffer_size -= len + 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774 }
775 size = buf - buffer;
776 }
777 return size;
778}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700779EXPORT_SYMBOL(generic_listxattr);
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400780
Andreas Gruenbachere409de92015-10-04 19:18:52 +0200781/**
782 * xattr_full_name - Compute full attribute name from suffix
783 *
784 * @handler: handler of the xattr_handler operation
785 * @name: name passed to the xattr_handler operation
786 *
787 * The get and set xattr handler operations are called with the remainder of
788 * the attribute name after skipping the handler's prefix: for example, "foo"
789 * is passed to the get operation of a handler with prefix "user." to get
790 * attribute "user.foo". The full name is still "there" in the name though.
791 *
792 * Note: the list xattr handler operation when called from the vfs is passed a
793 * NULL name; some file systems use this operation internally, with varying
794 * semantics.
795 */
796const char *xattr_full_name(const struct xattr_handler *handler,
797 const char *name)
798{
Andreas Gruenbacher98e9cb52015-12-02 14:44:36 +0100799 size_t prefix_len = strlen(xattr_prefix(handler));
Andreas Gruenbachere409de92015-10-04 19:18:52 +0200800
801 return name - prefix_len;
802}
803EXPORT_SYMBOL(xattr_full_name);
804
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400805/*
806 * Allocate new xattr and copy in the value; but leave the name to callers.
807 */
808struct simple_xattr *simple_xattr_alloc(const void *value, size_t size)
809{
810 struct simple_xattr *new_xattr;
811 size_t len;
812
813 /* wrap around? */
814 len = sizeof(*new_xattr) + size;
Hugh Dickins4e66d442014-07-23 14:00:17 -0700815 if (len < sizeof(*new_xattr))
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400816 return NULL;
817
818 new_xattr = kmalloc(len, GFP_KERNEL);
819 if (!new_xattr)
820 return NULL;
821
822 new_xattr->size = size;
823 memcpy(new_xattr->value, value, size);
824 return new_xattr;
825}
826
827/*
828 * xattr GET operation for in-memory/pseudo filesystems
829 */
830int simple_xattr_get(struct simple_xattrs *xattrs, const char *name,
831 void *buffer, size_t size)
832{
833 struct simple_xattr *xattr;
834 int ret = -ENODATA;
835
836 spin_lock(&xattrs->lock);
837 list_for_each_entry(xattr, &xattrs->head, list) {
838 if (strcmp(name, xattr->name))
839 continue;
840
841 ret = xattr->size;
842 if (buffer) {
843 if (size < xattr->size)
844 ret = -ERANGE;
845 else
846 memcpy(buffer, xattr->value, xattr->size);
847 }
848 break;
849 }
850 spin_unlock(&xattrs->lock);
851 return ret;
852}
853
Andreas Gruenbacheraa7c5242015-12-02 14:44:38 +0100854/**
855 * simple_xattr_set - xattr SET operation for in-memory/pseudo filesystems
856 * @xattrs: target simple_xattr list
857 * @name: name of the extended attribute
858 * @value: value of the xattr. If %NULL, will remove the attribute.
859 * @size: size of the new xattr
860 * @flags: %XATTR_{CREATE|REPLACE}
861 *
862 * %XATTR_CREATE is set, the xattr shouldn't exist already; otherwise fails
863 * with -EEXIST. If %XATTR_REPLACE is set, the xattr should exist;
864 * otherwise, fails with -ENODATA.
865 *
866 * Returns 0 on success, -errno on failure.
867 */
868int simple_xattr_set(struct simple_xattrs *xattrs, const char *name,
869 const void *value, size_t size, int flags)
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400870{
871 struct simple_xattr *xattr;
David Rientjes43385842012-10-17 20:41:15 -0700872 struct simple_xattr *new_xattr = NULL;
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400873 int err = 0;
874
875 /* value == NULL means remove */
876 if (value) {
877 new_xattr = simple_xattr_alloc(value, size);
878 if (!new_xattr)
879 return -ENOMEM;
880
881 new_xattr->name = kstrdup(name, GFP_KERNEL);
882 if (!new_xattr->name) {
883 kfree(new_xattr);
884 return -ENOMEM;
885 }
886 }
887
888 spin_lock(&xattrs->lock);
889 list_for_each_entry(xattr, &xattrs->head, list) {
890 if (!strcmp(name, xattr->name)) {
891 if (flags & XATTR_CREATE) {
892 xattr = new_xattr;
893 err = -EEXIST;
894 } else if (new_xattr) {
895 list_replace(&xattr->list, &new_xattr->list);
896 } else {
897 list_del(&xattr->list);
898 }
899 goto out;
900 }
901 }
902 if (flags & XATTR_REPLACE) {
903 xattr = new_xattr;
904 err = -ENODATA;
905 } else {
906 list_add(&new_xattr->list, &xattrs->head);
907 xattr = NULL;
908 }
909out:
910 spin_unlock(&xattrs->lock);
911 if (xattr) {
912 kfree(xattr->name);
913 kfree(xattr);
914 }
915 return err;
916
917}
918
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400919static bool xattr_is_trusted(const char *name)
920{
921 return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN);
922}
923
Andreas Gruenbacher786534b2015-12-02 14:44:39 +0100924static int xattr_list_one(char **buffer, ssize_t *remaining_size,
925 const char *name)
926{
927 size_t len = strlen(name) + 1;
928 if (*buffer) {
929 if (*remaining_size < len)
930 return -ERANGE;
931 memcpy(*buffer, name, len);
932 *buffer += len;
933 }
934 *remaining_size -= len;
935 return 0;
936}
937
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400938/*
939 * xattr LIST operation for in-memory/pseudo filesystems
940 */
Andreas Gruenbacher786534b2015-12-02 14:44:39 +0100941ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs,
942 char *buffer, size_t size)
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400943{
944 bool trusted = capable(CAP_SYS_ADMIN);
945 struct simple_xattr *xattr;
Andreas Gruenbacher786534b2015-12-02 14:44:39 +0100946 ssize_t remaining_size = size;
Mateusz Guzik0e9a7da2016-02-04 02:56:30 +0100947 int err = 0;
Andreas Gruenbacher786534b2015-12-02 14:44:39 +0100948
949#ifdef CONFIG_FS_POSIX_ACL
950 if (inode->i_acl) {
951 err = xattr_list_one(&buffer, &remaining_size,
952 XATTR_NAME_POSIX_ACL_ACCESS);
953 if (err)
954 return err;
955 }
956 if (inode->i_default_acl) {
957 err = xattr_list_one(&buffer, &remaining_size,
958 XATTR_NAME_POSIX_ACL_DEFAULT);
959 if (err)
960 return err;
961 }
962#endif
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400963
964 spin_lock(&xattrs->lock);
965 list_for_each_entry(xattr, &xattrs->head, list) {
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400966 /* skip "trusted." attributes for unprivileged callers */
967 if (!trusted && xattr_is_trusted(xattr->name))
968 continue;
969
Andreas Gruenbacher786534b2015-12-02 14:44:39 +0100970 err = xattr_list_one(&buffer, &remaining_size, xattr->name);
971 if (err)
Mateusz Guzik0e9a7da2016-02-04 02:56:30 +0100972 break;
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400973 }
974 spin_unlock(&xattrs->lock);
975
Mateusz Guzik0e9a7da2016-02-04 02:56:30 +0100976 return err ? err : size - remaining_size;
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400977}
978
Aristeu Rozanski48957682012-09-11 16:28:11 -0400979/*
980 * Adds an extended attribute to the list
981 */
Aristeu Rozanski38f38652012-08-23 16:53:28 -0400982void simple_xattr_list_add(struct simple_xattrs *xattrs,
983 struct simple_xattr *new_xattr)
984{
985 spin_lock(&xattrs->lock);
986 list_add(&new_xattr->list, &xattrs->head);
987 spin_unlock(&xattrs->lock);
988}