blob: 4beafc43daa58bff015f0839c78b5a65f8b8d2ab [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 File: fs/xattr.c
3
4 Extended attribute handling.
5
6 Copyright (C) 2001 by Andreas Gruenbacher <a.gruenbacher@computer.org>
7 Copyright (C) 2001 SGI - Silicon Graphics, Inc <linux-xfs@oss.sgi.com>
8 Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
9 */
10#include <linux/fs.h>
11#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#include <linux/file.h>
13#include <linux/xattr.h>
Dave Hansen18f335a2008-02-15 14:37:38 -080014#include <linux/mount.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/namei.h>
16#include <linux/security.h>
Mimi Zoharc7b87de2011-03-09 14:39:18 -050017#include <linux/evm.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070018#include <linux/syscalls.h>
Paul Gortmaker630d9c42011-11-16 23:57:37 -050019#include <linux/export.h>
Robert Love0eeca282005-07-12 17:06:03 -040020#include <linux/fsnotify.h>
Amy Griffis73241cc2005-11-03 16:00:25 +000021#include <linux/audit.h>
Andrew Morton0d08d7b2012-04-05 14:25:07 -070022#include <linux/vmalloc.h>
Eric W. Biederman2f6f0652012-02-07 18:52:57 -080023#include <linux/posix_acl_xattr.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070024
Andrew Morton0d08d7b2012-04-05 14:25:07 -070025#include <asm/uaccess.h>
Christoph Hellwig5be196e2006-01-09 20:51:55 -080026
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -080027/*
28 * Check permissions for extended attribute access. This is a bit complicated
29 * because different namespaces have very different rules.
30 */
31static int
32xattr_permission(struct inode *inode, const char *name, int mask)
33{
34 /*
35 * We can never set or remove an extended attribute on a read-only
36 * filesystem or on an immutable / append-only inode.
37 */
38 if (mask & MAY_WRITE) {
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -080039 if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
40 return -EPERM;
41 }
42
43 /*
44 * No restriction for security.* and system.* from the VFS. Decision
45 * on these is left to the underlying filesystem / security module.
46 */
47 if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) ||
48 !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
49 return 0;
50
51 /*
Andreas Gruenbacher55b23bd2011-05-27 14:50:36 +020052 * The trusted.* namespace can only be accessed by privileged users.
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -080053 */
Andreas Gruenbacher55b23bd2011-05-27 14:50:36 +020054 if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) {
55 if (!capable(CAP_SYS_ADMIN))
56 return (mask & MAY_WRITE) ? -EPERM : -ENODATA;
57 return 0;
58 }
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -080059
Andreas Gruenbacher55b23bd2011-05-27 14:50:36 +020060 /*
61 * In the user.* namespace, only regular files and directories can have
Andreas Gruenbacherf1f2d872006-11-02 22:07:29 -080062 * extended attributes. For sticky directories, only the owner and
Andreas Gruenbacher55b23bd2011-05-27 14:50:36 +020063 * privileged users can write attributes.
Andreas Gruenbacherf1f2d872006-11-02 22:07:29 -080064 */
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -080065 if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) {
Andreas Gruenbacherf1f2d872006-11-02 22:07:29 -080066 if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
Andreas Gruenbacher55b23bd2011-05-27 14:50:36 +020067 return (mask & MAY_WRITE) ? -EPERM : -ENODATA;
Andreas Gruenbacherf1f2d872006-11-02 22:07:29 -080068 if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) &&
Serge E. Hallyn2e149672011-03-23 16:43:26 -070069 (mask & MAY_WRITE) && !inode_owner_or_capable(inode))
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -080070 return -EPERM;
71 }
72
Al Virof419a2e2008-07-22 00:07:17 -040073 return inode_permission(inode, mask);
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -080074}
75
David P. Quigleyb1ab7e42009-09-03 14:25:56 -040076/**
77 * __vfs_setxattr_noperm - perform setxattr operation without performing
78 * permission checks.
79 *
80 * @dentry - object to perform setxattr on
81 * @name - xattr name to set
82 * @value - value to set @name to
83 * @size - size of @value
84 * @flags - flags to pass into filesystem operations
85 *
86 * returns the result of the internal setxattr or setsecurity operations.
87 *
88 * This function requires the caller to lock the inode's i_mutex before it
89 * is executed. It also assumes that the caller will make the appropriate
90 * permission checks.
91 */
92int __vfs_setxattr_noperm(struct dentry *dentry, const char *name,
93 const void *value, size_t size, int flags)
Christoph Hellwig5be196e2006-01-09 20:51:55 -080094{
95 struct inode *inode = dentry->d_inode;
David P. Quigleyb1ab7e42009-09-03 14:25:56 -040096 int error = -EOPNOTSUPP;
Andi Kleen69b45732011-05-28 08:25:51 -070097 int issec = !strncmp(name, XATTR_SECURITY_PREFIX,
98 XATTR_SECURITY_PREFIX_LEN);
Christoph Hellwig5be196e2006-01-09 20:51:55 -080099
Andi Kleen69b45732011-05-28 08:25:51 -0700100 if (issec)
101 inode->i_flags &= ~S_NOSEC;
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800102 if (inode->i_op->setxattr) {
Al Viro3767e252016-05-27 11:06:05 -0400103 error = inode->i_op->setxattr(dentry, inode, name, value, size, flags);
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800104 if (!error) {
105 fsnotify_xattr(dentry);
106 security_inode_post_setxattr(dentry, name, value,
107 size, flags);
108 }
Andi Kleen69b45732011-05-28 08:25:51 -0700109 } else if (issec) {
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800110 const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800111 error = security_inode_setsecurity(inode, suffix, value,
112 size, flags);
113 if (!error)
114 fsnotify_xattr(dentry);
115 }
David P. Quigleyb1ab7e42009-09-03 14:25:56 -0400116
117 return error;
118}
119
120
121int
122vfs_setxattr(struct dentry *dentry, const char *name, const void *value,
123 size_t size, int flags)
124{
125 struct inode *inode = dentry->d_inode;
126 int error;
127
128 error = xattr_permission(inode, name, MAY_WRITE);
129 if (error)
130 return error;
131
Al Viro59551022016-01-22 15:40:57 -0500132 inode_lock(inode);
David P. Quigleyb1ab7e42009-09-03 14:25:56 -0400133 error = security_inode_setxattr(dentry, name, value, size, flags);
134 if (error)
135 goto out;
136
137 error = __vfs_setxattr_noperm(dentry, name, value, size, flags);
138
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800139out:
Al Viro59551022016-01-22 15:40:57 -0500140 inode_unlock(inode);
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800141 return error;
142}
143EXPORT_SYMBOL_GPL(vfs_setxattr);
144
145ssize_t
David P. Quigley42492592008-02-04 22:29:39 -0800146xattr_getsecurity(struct inode *inode, const char *name, void *value,
147 size_t size)
148{
149 void *buffer = NULL;
150 ssize_t len;
151
152 if (!value || !size) {
153 len = security_inode_getsecurity(inode, name, &buffer, false);
154 goto out_noalloc;
155 }
156
157 len = security_inode_getsecurity(inode, name, &buffer, true);
158 if (len < 0)
159 return len;
160 if (size < len) {
161 len = -ERANGE;
162 goto out;
163 }
164 memcpy(value, buffer, len);
165out:
166 security_release_secctx(buffer, len);
167out_noalloc:
168 return len;
169}
170EXPORT_SYMBOL_GPL(xattr_getsecurity);
171
Mimi Zohar1601fba2011-03-09 14:23:34 -0500172/*
173 * vfs_getxattr_alloc - allocate memory, if necessary, before calling getxattr
174 *
175 * Allocate memory, if not already allocated, or re-allocate correct size,
176 * before retrieving the extended attribute.
177 *
178 * Returns the result of alloc, if failed, or the getxattr operation.
179 */
180ssize_t
181vfs_getxattr_alloc(struct dentry *dentry, const char *name, char **xattr_value,
182 size_t xattr_size, gfp_t flags)
183{
184 struct inode *inode = dentry->d_inode;
185 char *value = *xattr_value;
186 int error;
187
188 error = xattr_permission(inode, name, MAY_READ);
189 if (error)
190 return error;
191
192 if (!inode->i_op->getxattr)
193 return -EOPNOTSUPP;
194
Al Viroce23e642016-04-11 00:48:00 -0400195 error = inode->i_op->getxattr(dentry, inode, name, NULL, 0);
Mimi Zohar1601fba2011-03-09 14:23:34 -0500196 if (error < 0)
197 return error;
198
199 if (!value || (error > xattr_size)) {
200 value = krealloc(*xattr_value, error + 1, flags);
201 if (!value)
202 return -ENOMEM;
203 memset(value, 0, error + 1);
204 }
205
Al Viroce23e642016-04-11 00:48:00 -0400206 error = inode->i_op->getxattr(dentry, inode, name, value, error);
Mimi Zohar1601fba2011-03-09 14:23:34 -0500207 *xattr_value = value;
208 return error;
209}
210
David P. Quigley42492592008-02-04 22:29:39 -0800211ssize_t
David Howells8f0cfa52008-04-29 00:59:41 -0700212vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size)
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800213{
214 struct inode *inode = dentry->d_inode;
215 int error;
216
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800217 error = xattr_permission(inode, name, MAY_READ);
218 if (error)
219 return error;
220
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800221 error = security_inode_getxattr(dentry, name);
222 if (error)
223 return error;
224
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800225 if (!strncmp(name, XATTR_SECURITY_PREFIX,
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800226 XATTR_SECURITY_PREFIX_LEN)) {
227 const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
David P. Quigley42492592008-02-04 22:29:39 -0800228 int ret = xattr_getsecurity(inode, suffix, value, size);
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800229 /*
230 * Only overwrite the return value if a security module
231 * is actually active.
232 */
David P. Quigley4bea5802008-02-04 22:29:40 -0800233 if (ret == -EOPNOTSUPP)
234 goto nolsm;
235 return ret;
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800236 }
David P. Quigley4bea5802008-02-04 22:29:40 -0800237nolsm:
238 if (inode->i_op->getxattr)
Al Viroce23e642016-04-11 00:48:00 -0400239 error = inode->i_op->getxattr(dentry, inode, name, value, size);
David P. Quigley4bea5802008-02-04 22:29:40 -0800240 else
241 error = -EOPNOTSUPP;
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800242
243 return error;
244}
245EXPORT_SYMBOL_GPL(vfs_getxattr);
246
Bill Nottingham659564c2006-10-09 16:10:48 -0400247ssize_t
248vfs_listxattr(struct dentry *d, char *list, size_t size)
249{
250 ssize_t error;
251
252 error = security_inode_listxattr(d);
253 if (error)
254 return error;
255 error = -EOPNOTSUPP;
Al Viroacfa4382008-12-04 10:06:33 -0500256 if (d->d_inode->i_op->listxattr) {
Bill Nottingham659564c2006-10-09 16:10:48 -0400257 error = d->d_inode->i_op->listxattr(d, list, size);
258 } else {
259 error = security_inode_listsecurity(d->d_inode, list, size);
260 if (size && error > size)
261 error = -ERANGE;
262 }
263 return error;
264}
265EXPORT_SYMBOL_GPL(vfs_listxattr);
266
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800267int
David Howells8f0cfa52008-04-29 00:59:41 -0700268vfs_removexattr(struct dentry *dentry, const char *name)
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800269{
270 struct inode *inode = dentry->d_inode;
271 int error;
272
273 if (!inode->i_op->removexattr)
274 return -EOPNOTSUPP;
275
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800276 error = xattr_permission(inode, name, MAY_WRITE);
277 if (error)
278 return error;
279
Al Viro59551022016-01-22 15:40:57 -0500280 inode_lock(inode);
Mimi Zohar2ab51f32011-03-23 17:23:06 -0400281 error = security_inode_removexattr(dentry, name);
Dmitry Kasatkin7c51bb02014-11-20 16:31:01 +0200282 if (error)
283 goto out;
Mimi Zohar2ab51f32011-03-23 17:23:06 -0400284
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800285 error = inode->i_op->removexattr(dentry, name);
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800286
Mimi Zoharc7b87de2011-03-09 14:39:18 -0500287 if (!error) {
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800288 fsnotify_xattr(dentry);
Mimi Zoharc7b87de2011-03-09 14:39:18 -0500289 evm_inode_post_removexattr(dentry, name);
290 }
Dmitry Kasatkin7c51bb02014-11-20 16:31:01 +0200291
292out:
Al Viro59551022016-01-22 15:40:57 -0500293 inode_unlock(inode);
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800294 return error;
295}
296EXPORT_SYMBOL_GPL(vfs_removexattr);
297
298
Linus Torvalds1da177e2005-04-16 15:20:36 -0700299/*
300 * Extended attribute SET operations
301 */
302static long
David Howells8f0cfa52008-04-29 00:59:41 -0700303setxattr(struct dentry *d, const char __user *name, const void __user *value,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304 size_t size, int flags)
305{
306 int error;
307 void *kvalue = NULL;
308 char kname[XATTR_NAME_MAX + 1];
309
310 if (flags & ~(XATTR_CREATE|XATTR_REPLACE))
311 return -EINVAL;
312
313 error = strncpy_from_user(kname, name, sizeof(kname));
314 if (error == 0 || error == sizeof(kname))
315 error = -ERANGE;
316 if (error < 0)
317 return error;
318
319 if (size) {
320 if (size > XATTR_SIZE_MAX)
321 return -E2BIG;
Andrew Morton44c82492012-04-05 14:25:07 -0700322 kvalue = kmalloc(size, GFP_KERNEL | __GFP_NOWARN);
323 if (!kvalue) {
Richard Weinberger0b2a6f22016-01-02 23:09:47 +0100324 kvalue = vmalloc(size);
325 if (!kvalue)
Andrew Morton44c82492012-04-05 14:25:07 -0700326 return -ENOMEM;
Andrew Morton44c82492012-04-05 14:25:07 -0700327 }
328 if (copy_from_user(kvalue, value, size)) {
329 error = -EFAULT;
330 goto out;
331 }
Eric W. Biederman2f6f0652012-02-07 18:52:57 -0800332 if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
333 (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
334 posix_acl_fix_xattr_from_user(kvalue, size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700335 }
336
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800337 error = vfs_setxattr(d, kname, kvalue, size, flags);
Andrew Morton44c82492012-04-05 14:25:07 -0700338out:
Richard Weinberger0b2a6f22016-01-02 23:09:47 +0100339 kvfree(kvalue);
340
Linus Torvalds1da177e2005-04-16 15:20:36 -0700341 return error;
342}
343
Eric Biggers8cc43112014-10-12 11:59:58 -0500344static int path_setxattr(const char __user *pathname,
345 const char __user *name, const void __user *value,
346 size_t size, int flags, unsigned int lookup_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700347{
Al Viro2d8f3032008-07-22 09:59:21 -0400348 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700349 int error;
Jeff Layton68f1bb82012-12-11 12:10:15 -0500350retry:
351 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700352 if (error)
353 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400354 error = mnt_want_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800355 if (!error) {
Al Viro2d8f3032008-07-22 09:59:21 -0400356 error = setxattr(path.dentry, name, value, size, flags);
357 mnt_drop_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800358 }
Al Viro2d8f3032008-07-22 09:59:21 -0400359 path_put(&path);
Jeff Layton68f1bb82012-12-11 12:10:15 -0500360 if (retry_estale(error, lookup_flags)) {
361 lookup_flags |= LOOKUP_REVAL;
362 goto retry;
363 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364 return error;
365}
366
Eric Biggers8cc43112014-10-12 11:59:58 -0500367SYSCALL_DEFINE5(setxattr, const char __user *, pathname,
368 const char __user *, name, const void __user *, value,
369 size_t, size, int, flags)
370{
371 return path_setxattr(pathname, name, value, size, flags, LOOKUP_FOLLOW);
372}
373
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100374SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname,
375 const char __user *, name, const void __user *, value,
376 size_t, size, int, flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377{
Eric Biggers8cc43112014-10-12 11:59:58 -0500378 return path_setxattr(pathname, name, value, size, flags, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379}
380
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100381SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
382 const void __user *,value, size_t, size, int, flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383{
Al Viro2903ff02012-08-28 12:52:22 -0400384 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385 int error = -EBADF;
386
Al Viro2903ff02012-08-28 12:52:22 -0400387 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388 return error;
Al Viro9f45f5b2014-10-31 17:44:57 -0400389 audit_file(f.file);
Al Viro2903ff02012-08-28 12:52:22 -0400390 error = mnt_want_write_file(f.file);
Dave Hansen18f335a2008-02-15 14:37:38 -0800391 if (!error) {
Al Viro9f45f5b2014-10-31 17:44:57 -0400392 error = setxattr(f.file->f_path.dentry, name, value, size, flags);
Al Viro2903ff02012-08-28 12:52:22 -0400393 mnt_drop_write_file(f.file);
Dave Hansen18f335a2008-02-15 14:37:38 -0800394 }
Al Viro2903ff02012-08-28 12:52:22 -0400395 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396 return error;
397}
398
399/*
400 * Extended attribute GET operations
401 */
402static ssize_t
David Howells8f0cfa52008-04-29 00:59:41 -0700403getxattr(struct dentry *d, const char __user *name, void __user *value,
404 size_t size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405{
406 ssize_t error;
407 void *kvalue = NULL;
408 char kname[XATTR_NAME_MAX + 1];
409
410 error = strncpy_from_user(kname, name, sizeof(kname));
411 if (error == 0 || error == sizeof(kname))
412 error = -ERANGE;
413 if (error < 0)
414 return error;
415
416 if (size) {
417 if (size > XATTR_SIZE_MAX)
418 size = XATTR_SIZE_MAX;
Sasha Levin779302e2012-07-30 14:39:13 -0700419 kvalue = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);
420 if (!kvalue) {
Richard Weinberger0b2a6f22016-01-02 23:09:47 +0100421 kvalue = vmalloc(size);
422 if (!kvalue)
Sasha Levin779302e2012-07-30 14:39:13 -0700423 return -ENOMEM;
Sasha Levin779302e2012-07-30 14:39:13 -0700424 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700425 }
426
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800427 error = vfs_getxattr(d, kname, kvalue, size);
Stephen Smalleyf549d6c2005-09-03 15:55:18 -0700428 if (error > 0) {
Eric W. Biederman2f6f0652012-02-07 18:52:57 -0800429 if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) ||
430 (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))
431 posix_acl_fix_xattr_to_user(kvalue, size);
Stephen Smalleyf549d6c2005-09-03 15:55:18 -0700432 if (size && copy_to_user(value, kvalue, error))
433 error = -EFAULT;
434 } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) {
435 /* The file system tried to returned a value bigger
436 than XATTR_SIZE_MAX bytes. Not possible. */
437 error = -E2BIG;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700438 }
Richard Weinberger0b2a6f22016-01-02 23:09:47 +0100439
440 kvfree(kvalue);
441
Linus Torvalds1da177e2005-04-16 15:20:36 -0700442 return error;
443}
444
Eric Biggers8cc43112014-10-12 11:59:58 -0500445static ssize_t path_getxattr(const char __user *pathname,
446 const char __user *name, void __user *value,
447 size_t size, unsigned int lookup_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448{
Al Viro2d8f3032008-07-22 09:59:21 -0400449 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450 ssize_t error;
Jeff Layton60e66b42012-12-11 12:10:16 -0500451retry:
452 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700453 if (error)
454 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400455 error = getxattr(path.dentry, name, value, size);
456 path_put(&path);
Jeff Layton60e66b42012-12-11 12:10:16 -0500457 if (retry_estale(error, lookup_flags)) {
458 lookup_flags |= LOOKUP_REVAL;
459 goto retry;
460 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461 return error;
462}
463
Eric Biggers8cc43112014-10-12 11:59:58 -0500464SYSCALL_DEFINE4(getxattr, const char __user *, pathname,
465 const char __user *, name, void __user *, value, size_t, size)
466{
467 return path_getxattr(pathname, name, value, size, LOOKUP_FOLLOW);
468}
469
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100470SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname,
471 const char __user *, name, void __user *, value, size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472{
Eric Biggers8cc43112014-10-12 11:59:58 -0500473 return path_getxattr(pathname, name, value, size, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700474}
475
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100476SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name,
477 void __user *, value, size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478{
Al Viro2903ff02012-08-28 12:52:22 -0400479 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480 ssize_t error = -EBADF;
481
Al Viro2903ff02012-08-28 12:52:22 -0400482 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483 return error;
Al Viro9f45f5b2014-10-31 17:44:57 -0400484 audit_file(f.file);
Al Viro2903ff02012-08-28 12:52:22 -0400485 error = getxattr(f.file->f_path.dentry, name, value, size);
486 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700487 return error;
488}
489
490/*
491 * Extended attribute LIST operations
492 */
493static ssize_t
494listxattr(struct dentry *d, char __user *list, size_t size)
495{
496 ssize_t error;
497 char *klist = NULL;
498
499 if (size) {
500 if (size > XATTR_LIST_MAX)
501 size = XATTR_LIST_MAX;
Dave Jones703bf2d2012-04-05 14:25:06 -0700502 klist = kmalloc(size, __GFP_NOWARN | GFP_KERNEL);
Andrew Morton0d08d7b2012-04-05 14:25:07 -0700503 if (!klist) {
Richard Weinberger0b2a6f22016-01-02 23:09:47 +0100504 klist = vmalloc(size);
505 if (!klist)
Andrew Morton0d08d7b2012-04-05 14:25:07 -0700506 return -ENOMEM;
Andrew Morton0d08d7b2012-04-05 14:25:07 -0700507 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 }
509
Bill Nottingham659564c2006-10-09 16:10:48 -0400510 error = vfs_listxattr(d, klist, size);
Stephen Smalleyf549d6c2005-09-03 15:55:18 -0700511 if (error > 0) {
512 if (size && copy_to_user(list, klist, error))
513 error = -EFAULT;
514 } else if (error == -ERANGE && size >= XATTR_LIST_MAX) {
515 /* The file system tried to returned a list bigger
516 than XATTR_LIST_MAX bytes. Not possible. */
517 error = -E2BIG;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700518 }
Richard Weinberger0b2a6f22016-01-02 23:09:47 +0100519
520 kvfree(klist);
521
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522 return error;
523}
524
Eric Biggers8cc43112014-10-12 11:59:58 -0500525static ssize_t path_listxattr(const char __user *pathname, char __user *list,
526 size_t size, unsigned int lookup_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700527{
Al Viro2d8f3032008-07-22 09:59:21 -0400528 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700529 ssize_t error;
Jeff Layton10a90cf2012-12-11 12:10:16 -0500530retry:
531 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700532 if (error)
533 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400534 error = listxattr(path.dentry, list, size);
535 path_put(&path);
Jeff Layton10a90cf2012-12-11 12:10:16 -0500536 if (retry_estale(error, lookup_flags)) {
537 lookup_flags |= LOOKUP_REVAL;
538 goto retry;
539 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700540 return error;
541}
542
Eric Biggers8cc43112014-10-12 11:59:58 -0500543SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list,
544 size_t, size)
545{
546 return path_listxattr(pathname, list, size, LOOKUP_FOLLOW);
547}
548
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100549SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list,
550 size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551{
Eric Biggers8cc43112014-10-12 11:59:58 -0500552 return path_listxattr(pathname, list, size, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553}
554
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100555SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556{
Al Viro2903ff02012-08-28 12:52:22 -0400557 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700558 ssize_t error = -EBADF;
559
Al Viro2903ff02012-08-28 12:52:22 -0400560 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561 return error;
Al Viro9f45f5b2014-10-31 17:44:57 -0400562 audit_file(f.file);
Al Viro2903ff02012-08-28 12:52:22 -0400563 error = listxattr(f.file->f_path.dentry, list, size);
564 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565 return error;
566}
567
568/*
569 * Extended attribute REMOVE operations
570 */
571static long
David Howells8f0cfa52008-04-29 00:59:41 -0700572removexattr(struct dentry *d, const char __user *name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573{
574 int error;
575 char kname[XATTR_NAME_MAX + 1];
576
577 error = strncpy_from_user(kname, name, sizeof(kname));
578 if (error == 0 || error == sizeof(kname))
579 error = -ERANGE;
580 if (error < 0)
581 return error;
582
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800583 return vfs_removexattr(d, kname);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584}
585
Eric Biggers8cc43112014-10-12 11:59:58 -0500586static int path_removexattr(const char __user *pathname,
587 const char __user *name, unsigned int lookup_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700588{
Al Viro2d8f3032008-07-22 09:59:21 -0400589 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700590 int error;
Jeff Layton12f06212012-12-11 12:10:17 -0500591retry:
592 error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700593 if (error)
594 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400595 error = mnt_want_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800596 if (!error) {
Al Viro2d8f3032008-07-22 09:59:21 -0400597 error = removexattr(path.dentry, name);
598 mnt_drop_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800599 }
Al Viro2d8f3032008-07-22 09:59:21 -0400600 path_put(&path);
Jeff Layton12f06212012-12-11 12:10:17 -0500601 if (retry_estale(error, lookup_flags)) {
602 lookup_flags |= LOOKUP_REVAL;
603 goto retry;
604 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605 return error;
606}
607
Eric Biggers8cc43112014-10-12 11:59:58 -0500608SYSCALL_DEFINE2(removexattr, const char __user *, pathname,
609 const char __user *, name)
610{
611 return path_removexattr(pathname, name, LOOKUP_FOLLOW);
612}
613
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100614SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname,
615 const char __user *, name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700616{
Eric Biggers8cc43112014-10-12 11:59:58 -0500617 return path_removexattr(pathname, name, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700618}
619
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100620SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700621{
Al Viro2903ff02012-08-28 12:52:22 -0400622 struct fd f = fdget(fd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700623 int error = -EBADF;
624
Al Viro2903ff02012-08-28 12:52:22 -0400625 if (!f.file)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700626 return error;
Al Viro9f45f5b2014-10-31 17:44:57 -0400627 audit_file(f.file);
Al Viro2903ff02012-08-28 12:52:22 -0400628 error = mnt_want_write_file(f.file);
Dave Hansen18f335a2008-02-15 14:37:38 -0800629 if (!error) {
Al Viro9f45f5b2014-10-31 17:44:57 -0400630 error = removexattr(f.file->f_path.dentry, name);
Al Viro2903ff02012-08-28 12:52:22 -0400631 mnt_drop_write_file(f.file);
Dave Hansen18f335a2008-02-15 14:37:38 -0800632 }
Al Viro2903ff02012-08-28 12:52:22 -0400633 fdput(f);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700634 return error;
635}
636
637
638static const char *
639strcmp_prefix(const char *a, const char *a_prefix)
640{
641 while (*a_prefix && *a == *a_prefix) {
642 a++;
643 a_prefix++;
644 }
645 return *a_prefix ? NULL : a;
646}
647
648/*
649 * In order to implement different sets of xattr operations for each xattr
650 * prefix with the generic xattr API, a filesystem should create a
651 * null-terminated array of struct xattr_handler (one for each prefix) and
652 * hang a pointer to it off of the s_xattr field of the superblock.
653 *
654 * The generic_fooxattr() functions will use this list to dispatch xattr
655 * operations to the correct xattr_handler.
656 */
657#define for_each_xattr_handler(handlers, handler) \
Al Viro00407732016-05-25 17:34:41 -0400658 if (handlers) \
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659 for ((handler) = *(handlers)++; \
660 (handler) != NULL; \
661 (handler) = *(handlers)++)
662
663/*
664 * Find the xattr_handler with the matching prefix.
665 */
Stephen Hemmingerbb435452010-05-13 17:53:14 -0700666static const struct xattr_handler *
667xattr_resolve_name(const struct xattr_handler **handlers, const char **name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700668{
Stephen Hemmingerbb435452010-05-13 17:53:14 -0700669 const struct xattr_handler *handler;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700670
671 if (!*name)
Andreas Gruenbacheraaf431b2016-05-09 13:28:49 +0200672 return ERR_PTR(-EINVAL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673
674 for_each_xattr_handler(handlers, handler) {
Andreas Gruenbacher98e9cb52015-12-02 14:44:36 +0100675 const char *n;
676
677 n = strcmp_prefix(*name, xattr_prefix(handler));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700678 if (n) {
Andreas Gruenbacher98e9cb52015-12-02 14:44:36 +0100679 if (!handler->prefix ^ !*n) {
680 if (*n)
681 continue;
682 return ERR_PTR(-EINVAL);
683 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684 *name = n;
Andreas Gruenbacher98e9cb52015-12-02 14:44:36 +0100685 return handler;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700686 }
687 }
Andreas Gruenbacher98e9cb52015-12-02 14:44:36 +0100688 return ERR_PTR(-EOPNOTSUPP);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700689}
690
691/*
692 * Find the handler for the prefix and dispatch its get() operation.
693 */
694ssize_t
Al Viroce23e642016-04-11 00:48:00 -0400695generic_getxattr(struct dentry *dentry, struct inode *inode,
696 const char *name, void *buffer, size_t size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697{
Stephen Hemmingerbb435452010-05-13 17:53:14 -0700698 const struct xattr_handler *handler;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700699
Christoph Hellwig431547b2009-11-13 09:52:56 +0000700 handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
Andreas Gruenbacher98e9cb52015-12-02 14:44:36 +0100701 if (IS_ERR(handler))
702 return PTR_ERR(handler);
Al Viroce23e642016-04-11 00:48:00 -0400703 return handler->get(handler, dentry, inode,
Al Virob2968212016-04-10 20:48:24 -0400704 name, buffer, size);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700705}
706
707/*
708 * Combine the results of the list() operation from every xattr_handler in the
709 * list.
710 */
711ssize_t
712generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
713{
Stephen Hemmingerbb435452010-05-13 17:53:14 -0700714 const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700715 unsigned int size = 0;
716
717 if (!buffer) {
Christoph Hellwig431547b2009-11-13 09:52:56 +0000718 for_each_xattr_handler(handlers, handler) {
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100719 if (!handler->name ||
720 (handler->list && !handler->list(dentry)))
Andreas Gruenbacherc4803c42015-12-02 14:44:41 +0100721 continue;
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100722 size += strlen(handler->name) + 1;
Christoph Hellwig431547b2009-11-13 09:52:56 +0000723 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700724 } else {
725 char *buf = buffer;
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100726 size_t len;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727
728 for_each_xattr_handler(handlers, handler) {
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100729 if (!handler->name ||
730 (handler->list && !handler->list(dentry)))
Andreas Gruenbacherc4803c42015-12-02 14:44:41 +0100731 continue;
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100732 len = strlen(handler->name);
733 if (len + 1 > buffer_size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700734 return -ERANGE;
Andreas Gruenbacher764a5c62015-12-02 14:44:43 +0100735 memcpy(buf, handler->name, len + 1);
736 buf += len + 1;
737 buffer_size -= len + 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700738 }
739 size = buf - buffer;
740 }
741 return size;
742}
743
744/*
745 * Find the handler for the prefix and dispatch its set() operation.
746 */
747int
Al Viro3767e252016-05-27 11:06:05 -0400748generic_setxattr(struct dentry *dentry, struct inode *inode, const char *name,
749 const void *value, size_t size, int flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700750{
Stephen Hemmingerbb435452010-05-13 17:53:14 -0700751 const struct xattr_handler *handler;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700752
753 if (size == 0)
754 value = ""; /* empty EA, do not remove */
Christoph Hellwig431547b2009-11-13 09:52:56 +0000755 handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
Andreas Gruenbacher98e9cb52015-12-02 14:44:36 +0100756 if (IS_ERR(handler))
757 return PTR_ERR(handler);
Al Viro3767e252016-05-27 11:06:05 -0400758 return handler->set(handler, dentry, inode, name, value, size, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700759}
760
761/*
762 * Find the handler for the prefix and dispatch its set() operation to remove
763 * any associated extended attribute.
764 */
765int
766generic_removexattr(struct dentry *dentry, const char *name)
767{
Stephen Hemmingerbb435452010-05-13 17:53:14 -0700768 const struct xattr_handler *handler;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700769
Christoph Hellwig431547b2009-11-13 09:52:56 +0000770 handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
Andreas Gruenbacher98e9cb52015-12-02 14:44:36 +0100771 if (IS_ERR(handler))
772 return PTR_ERR(handler);
Al Viro59301222016-05-27 10:19:30 -0400773 return handler->set(handler, dentry, d_inode(dentry), name, NULL,
774 0, XATTR_REPLACE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700775}
776
777EXPORT_SYMBOL(generic_getxattr);
778EXPORT_SYMBOL(generic_listxattr);
779EXPORT_SYMBOL(generic_setxattr);
780EXPORT_SYMBOL(generic_removexattr);
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}