blob: 1d7ac379045879b827b196f0d7a7420fe33c783d [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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070023
Andrew Morton0d08d7b2012-04-05 14:25:07 -070024#include <asm/uaccess.h>
Christoph Hellwig5be196e2006-01-09 20:51:55 -080025
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -080026/*
27 * Check permissions for extended attribute access. This is a bit complicated
28 * because different namespaces have very different rules.
29 */
30static int
31xattr_permission(struct inode *inode, const char *name, int mask)
32{
33 /*
34 * We can never set or remove an extended attribute on a read-only
35 * filesystem or on an immutable / append-only inode.
36 */
37 if (mask & MAY_WRITE) {
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -080038 if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
39 return -EPERM;
40 }
41
42 /*
43 * No restriction for security.* and system.* from the VFS. Decision
44 * on these is left to the underlying filesystem / security module.
45 */
46 if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) ||
47 !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
48 return 0;
49
50 /*
Andreas Gruenbacher55b23bd2011-05-27 14:50:36 +020051 * The trusted.* namespace can only be accessed by privileged users.
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -080052 */
Andreas Gruenbacher55b23bd2011-05-27 14:50:36 +020053 if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) {
54 if (!capable(CAP_SYS_ADMIN))
55 return (mask & MAY_WRITE) ? -EPERM : -ENODATA;
56 return 0;
57 }
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -080058
Andreas Gruenbacher55b23bd2011-05-27 14:50:36 +020059 /*
60 * In the user.* namespace, only regular files and directories can have
Andreas Gruenbacherf1f2d872006-11-02 22:07:29 -080061 * extended attributes. For sticky directories, only the owner and
Andreas Gruenbacher55b23bd2011-05-27 14:50:36 +020062 * privileged users can write attributes.
Andreas Gruenbacherf1f2d872006-11-02 22:07:29 -080063 */
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -080064 if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) {
Andreas Gruenbacherf1f2d872006-11-02 22:07:29 -080065 if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode))
Andreas Gruenbacher55b23bd2011-05-27 14:50:36 +020066 return (mask & MAY_WRITE) ? -EPERM : -ENODATA;
Andreas Gruenbacherf1f2d872006-11-02 22:07:29 -080067 if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) &&
Serge E. Hallyn2e149672011-03-23 16:43:26 -070068 (mask & MAY_WRITE) && !inode_owner_or_capable(inode))
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -080069 return -EPERM;
70 }
71
Al Virof419a2e2008-07-22 00:07:17 -040072 return inode_permission(inode, mask);
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -080073}
74
David P. Quigleyb1ab7e42009-09-03 14:25:56 -040075/**
76 * __vfs_setxattr_noperm - perform setxattr operation without performing
77 * permission checks.
78 *
79 * @dentry - object to perform setxattr on
80 * @name - xattr name to set
81 * @value - value to set @name to
82 * @size - size of @value
83 * @flags - flags to pass into filesystem operations
84 *
85 * returns the result of the internal setxattr or setsecurity operations.
86 *
87 * This function requires the caller to lock the inode's i_mutex before it
88 * is executed. It also assumes that the caller will make the appropriate
89 * permission checks.
90 */
91int __vfs_setxattr_noperm(struct dentry *dentry, const char *name,
92 const void *value, size_t size, int flags)
Christoph Hellwig5be196e2006-01-09 20:51:55 -080093{
94 struct inode *inode = dentry->d_inode;
David P. Quigleyb1ab7e42009-09-03 14:25:56 -040095 int error = -EOPNOTSUPP;
Andi Kleen69b45732011-05-28 08:25:51 -070096 int issec = !strncmp(name, XATTR_SECURITY_PREFIX,
97 XATTR_SECURITY_PREFIX_LEN);
Christoph Hellwig5be196e2006-01-09 20:51:55 -080098
Andi Kleen69b45732011-05-28 08:25:51 -070099 if (issec)
100 inode->i_flags &= ~S_NOSEC;
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800101 if (inode->i_op->setxattr) {
102 error = inode->i_op->setxattr(dentry, name, value, size, flags);
103 if (!error) {
104 fsnotify_xattr(dentry);
105 security_inode_post_setxattr(dentry, name, value,
106 size, flags);
107 }
Andi Kleen69b45732011-05-28 08:25:51 -0700108 } else if (issec) {
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800109 const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800110 error = security_inode_setsecurity(inode, suffix, value,
111 size, flags);
112 if (!error)
113 fsnotify_xattr(dentry);
114 }
David P. Quigleyb1ab7e42009-09-03 14:25:56 -0400115
116 return error;
117}
118
119
120int
121vfs_setxattr(struct dentry *dentry, const char *name, const void *value,
122 size_t size, int flags)
123{
124 struct inode *inode = dentry->d_inode;
125 int error;
126
127 error = xattr_permission(inode, name, MAY_WRITE);
128 if (error)
129 return error;
130
131 mutex_lock(&inode->i_mutex);
132 error = security_inode_setxattr(dentry, name, value, size, flags);
133 if (error)
134 goto out;
135
136 error = __vfs_setxattr_noperm(dentry, name, value, size, flags);
137
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800138out:
139 mutex_unlock(&inode->i_mutex);
140 return error;
141}
142EXPORT_SYMBOL_GPL(vfs_setxattr);
143
144ssize_t
David P. Quigley42492592008-02-04 22:29:39 -0800145xattr_getsecurity(struct inode *inode, const char *name, void *value,
146 size_t size)
147{
148 void *buffer = NULL;
149 ssize_t len;
150
151 if (!value || !size) {
152 len = security_inode_getsecurity(inode, name, &buffer, false);
153 goto out_noalloc;
154 }
155
156 len = security_inode_getsecurity(inode, name, &buffer, true);
157 if (len < 0)
158 return len;
159 if (size < len) {
160 len = -ERANGE;
161 goto out;
162 }
163 memcpy(value, buffer, len);
164out:
165 security_release_secctx(buffer, len);
166out_noalloc:
167 return len;
168}
169EXPORT_SYMBOL_GPL(xattr_getsecurity);
170
Mimi Zohar1601fba2011-03-09 14:23:34 -0500171/*
172 * vfs_getxattr_alloc - allocate memory, if necessary, before calling getxattr
173 *
174 * Allocate memory, if not already allocated, or re-allocate correct size,
175 * before retrieving the extended attribute.
176 *
177 * Returns the result of alloc, if failed, or the getxattr operation.
178 */
179ssize_t
180vfs_getxattr_alloc(struct dentry *dentry, const char *name, char **xattr_value,
181 size_t xattr_size, gfp_t flags)
182{
183 struct inode *inode = dentry->d_inode;
184 char *value = *xattr_value;
185 int error;
186
187 error = xattr_permission(inode, name, MAY_READ);
188 if (error)
189 return error;
190
191 if (!inode->i_op->getxattr)
192 return -EOPNOTSUPP;
193
194 error = inode->i_op->getxattr(dentry, name, NULL, 0);
195 if (error < 0)
196 return error;
197
198 if (!value || (error > xattr_size)) {
199 value = krealloc(*xattr_value, error + 1, flags);
200 if (!value)
201 return -ENOMEM;
202 memset(value, 0, error + 1);
203 }
204
205 error = inode->i_op->getxattr(dentry, name, value, error);
206 *xattr_value = value;
207 return error;
208}
209
210/* Compare an extended attribute value with the given value */
211int vfs_xattr_cmp(struct dentry *dentry, const char *xattr_name,
212 const char *value, size_t size, gfp_t flags)
213{
214 char *xattr_value = NULL;
215 int rc;
216
217 rc = vfs_getxattr_alloc(dentry, xattr_name, &xattr_value, 0, flags);
218 if (rc < 0)
219 return rc;
220
221 if ((rc != size) || (memcmp(xattr_value, value, rc) != 0))
222 rc = -EINVAL;
223 else
224 rc = 0;
225 kfree(xattr_value);
226 return rc;
227}
228
David P. Quigley42492592008-02-04 22:29:39 -0800229ssize_t
David Howells8f0cfa52008-04-29 00:59:41 -0700230vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size)
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800231{
232 struct inode *inode = dentry->d_inode;
233 int error;
234
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800235 error = xattr_permission(inode, name, MAY_READ);
236 if (error)
237 return error;
238
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800239 error = security_inode_getxattr(dentry, name);
240 if (error)
241 return error;
242
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800243 if (!strncmp(name, XATTR_SECURITY_PREFIX,
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800244 XATTR_SECURITY_PREFIX_LEN)) {
245 const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
David P. Quigley42492592008-02-04 22:29:39 -0800246 int ret = xattr_getsecurity(inode, suffix, value, size);
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800247 /*
248 * Only overwrite the return value if a security module
249 * is actually active.
250 */
David P. Quigley4bea5802008-02-04 22:29:40 -0800251 if (ret == -EOPNOTSUPP)
252 goto nolsm;
253 return ret;
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800254 }
David P. Quigley4bea5802008-02-04 22:29:40 -0800255nolsm:
256 if (inode->i_op->getxattr)
257 error = inode->i_op->getxattr(dentry, name, value, size);
258 else
259 error = -EOPNOTSUPP;
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800260
261 return error;
262}
263EXPORT_SYMBOL_GPL(vfs_getxattr);
264
Bill Nottingham659564c2006-10-09 16:10:48 -0400265ssize_t
266vfs_listxattr(struct dentry *d, char *list, size_t size)
267{
268 ssize_t error;
269
270 error = security_inode_listxattr(d);
271 if (error)
272 return error;
273 error = -EOPNOTSUPP;
Al Viroacfa4382008-12-04 10:06:33 -0500274 if (d->d_inode->i_op->listxattr) {
Bill Nottingham659564c2006-10-09 16:10:48 -0400275 error = d->d_inode->i_op->listxattr(d, list, size);
276 } else {
277 error = security_inode_listsecurity(d->d_inode, list, size);
278 if (size && error > size)
279 error = -ERANGE;
280 }
281 return error;
282}
283EXPORT_SYMBOL_GPL(vfs_listxattr);
284
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800285int
David Howells8f0cfa52008-04-29 00:59:41 -0700286vfs_removexattr(struct dentry *dentry, const char *name)
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800287{
288 struct inode *inode = dentry->d_inode;
289 int error;
290
291 if (!inode->i_op->removexattr)
292 return -EOPNOTSUPP;
293
akpm@osdl.orge0ad7b02006-01-09 20:51:56 -0800294 error = xattr_permission(inode, name, MAY_WRITE);
295 if (error)
296 return error;
297
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800298 error = security_inode_removexattr(dentry, name);
299 if (error)
300 return error;
301
302 mutex_lock(&inode->i_mutex);
303 error = inode->i_op->removexattr(dentry, name);
304 mutex_unlock(&inode->i_mutex);
305
Mimi Zoharc7b87de2011-03-09 14:39:18 -0500306 if (!error) {
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800307 fsnotify_xattr(dentry);
Mimi Zoharc7b87de2011-03-09 14:39:18 -0500308 evm_inode_post_removexattr(dentry, name);
309 }
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800310 return error;
311}
312EXPORT_SYMBOL_GPL(vfs_removexattr);
313
314
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315/*
316 * Extended attribute SET operations
317 */
318static long
David Howells8f0cfa52008-04-29 00:59:41 -0700319setxattr(struct dentry *d, const char __user *name, const void __user *value,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320 size_t size, int flags)
321{
322 int error;
323 void *kvalue = NULL;
Andrew Morton44c82492012-04-05 14:25:07 -0700324 void *vvalue = NULL; /* If non-NULL, we used vmalloc() */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325 char kname[XATTR_NAME_MAX + 1];
326
327 if (flags & ~(XATTR_CREATE|XATTR_REPLACE))
328 return -EINVAL;
329
330 error = strncpy_from_user(kname, name, sizeof(kname));
331 if (error == 0 || error == sizeof(kname))
332 error = -ERANGE;
333 if (error < 0)
334 return error;
335
336 if (size) {
337 if (size > XATTR_SIZE_MAX)
338 return -E2BIG;
Andrew Morton44c82492012-04-05 14:25:07 -0700339 kvalue = kmalloc(size, GFP_KERNEL | __GFP_NOWARN);
340 if (!kvalue) {
341 vvalue = vmalloc(size);
342 if (!vvalue)
343 return -ENOMEM;
344 kvalue = vvalue;
345 }
346 if (copy_from_user(kvalue, value, size)) {
347 error = -EFAULT;
348 goto out;
349 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700350 }
351
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800352 error = vfs_setxattr(d, kname, kvalue, size, flags);
Andrew Morton44c82492012-04-05 14:25:07 -0700353out:
354 if (vvalue)
355 vfree(vvalue);
356 else
357 kfree(kvalue);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358 return error;
359}
360
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100361SYSCALL_DEFINE5(setxattr, const char __user *, pathname,
362 const char __user *, name, const void __user *, value,
363 size_t, size, int, flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364{
Al Viro2d8f3032008-07-22 09:59:21 -0400365 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366 int error;
367
Al Viro2d8f3032008-07-22 09:59:21 -0400368 error = user_path(pathname, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700369 if (error)
370 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400371 error = mnt_want_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800372 if (!error) {
Al Viro2d8f3032008-07-22 09:59:21 -0400373 error = setxattr(path.dentry, name, value, size, flags);
374 mnt_drop_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800375 }
Al Viro2d8f3032008-07-22 09:59:21 -0400376 path_put(&path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700377 return error;
378}
379
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100380SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname,
381 const char __user *, name, const void __user *, value,
382 size_t, size, int, flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383{
Al Viro2d8f3032008-07-22 09:59:21 -0400384 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385 int error;
386
Al Viro2d8f3032008-07-22 09:59:21 -0400387 error = user_lpath(pathname, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388 if (error)
389 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400390 error = mnt_want_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800391 if (!error) {
Al Viro2d8f3032008-07-22 09:59:21 -0400392 error = setxattr(path.dentry, name, value, size, flags);
393 mnt_drop_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800394 }
Al Viro2d8f3032008-07-22 09:59:21 -0400395 path_put(&path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396 return error;
397}
398
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100399SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name,
400 const void __user *,value, size_t, size, int, flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401{
Al Viro7449af12012-04-21 18:41:25 -0400402 int fput_needed;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403 struct file *f;
Amy Griffis73241cc2005-11-03 16:00:25 +0000404 struct dentry *dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405 int error = -EBADF;
406
Al Viro7449af12012-04-21 18:41:25 -0400407 f = fget_light(fd, &fput_needed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700408 if (!f)
409 return error;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800410 dentry = f->f_path.dentry;
Al Viro5a190ae2007-06-07 12:19:32 -0400411 audit_inode(NULL, dentry);
npiggin@suse.de96029c42009-04-26 20:25:55 +1000412 error = mnt_want_write_file(f);
Dave Hansen18f335a2008-02-15 14:37:38 -0800413 if (!error) {
414 error = setxattr(dentry, name, value, size, flags);
Al Viro2a79f172011-12-09 08:06:57 -0500415 mnt_drop_write_file(f);
Dave Hansen18f335a2008-02-15 14:37:38 -0800416 }
Al Viro7449af12012-04-21 18:41:25 -0400417 fput_light(f, fput_needed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700418 return error;
419}
420
421/*
422 * Extended attribute GET operations
423 */
424static ssize_t
David Howells8f0cfa52008-04-29 00:59:41 -0700425getxattr(struct dentry *d, const char __user *name, void __user *value,
426 size_t size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427{
428 ssize_t error;
429 void *kvalue = NULL;
430 char kname[XATTR_NAME_MAX + 1];
431
432 error = strncpy_from_user(kname, name, sizeof(kname));
433 if (error == 0 || error == sizeof(kname))
434 error = -ERANGE;
435 if (error < 0)
436 return error;
437
438 if (size) {
439 if (size > XATTR_SIZE_MAX)
440 size = XATTR_SIZE_MAX;
James Morrisd381d8a2005-10-30 14:59:22 -0800441 kvalue = kzalloc(size, GFP_KERNEL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700442 if (!kvalue)
443 return -ENOMEM;
444 }
445
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800446 error = vfs_getxattr(d, kname, kvalue, size);
Stephen Smalleyf549d6c2005-09-03 15:55:18 -0700447 if (error > 0) {
448 if (size && copy_to_user(value, kvalue, error))
449 error = -EFAULT;
450 } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) {
451 /* The file system tried to returned a value bigger
452 than XATTR_SIZE_MAX bytes. Not possible. */
453 error = -E2BIG;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700454 }
Jesper Juhlf99d49a2005-11-07 01:01:34 -0800455 kfree(kvalue);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700456 return error;
457}
458
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100459SYSCALL_DEFINE4(getxattr, const char __user *, pathname,
460 const char __user *, name, void __user *, value, size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461{
Al Viro2d8f3032008-07-22 09:59:21 -0400462 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463 ssize_t error;
464
Al Viro2d8f3032008-07-22 09:59:21 -0400465 error = user_path(pathname, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466 if (error)
467 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400468 error = getxattr(path.dentry, name, value, size);
469 path_put(&path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700470 return error;
471}
472
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100473SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname,
474 const char __user *, name, void __user *, value, size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700475{
Al Viro2d8f3032008-07-22 09:59:21 -0400476 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477 ssize_t error;
478
Al Viro2d8f3032008-07-22 09:59:21 -0400479 error = user_lpath(pathname, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700480 if (error)
481 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400482 error = getxattr(path.dentry, name, value, size);
483 path_put(&path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484 return error;
485}
486
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100487SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name,
488 void __user *, value, size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489{
Al Viro7449af12012-04-21 18:41:25 -0400490 int fput_needed;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491 struct file *f;
492 ssize_t error = -EBADF;
493
Al Viro7449af12012-04-21 18:41:25 -0400494 f = fget_light(fd, &fput_needed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700495 if (!f)
496 return error;
Al Viro5a190ae2007-06-07 12:19:32 -0400497 audit_inode(NULL, f->f_path.dentry);
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800498 error = getxattr(f->f_path.dentry, name, value, size);
Al Viro7449af12012-04-21 18:41:25 -0400499 fput_light(f, fput_needed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700500 return error;
501}
502
503/*
504 * Extended attribute LIST operations
505 */
506static ssize_t
507listxattr(struct dentry *d, char __user *list, size_t size)
508{
509 ssize_t error;
510 char *klist = NULL;
Andrew Morton0d08d7b2012-04-05 14:25:07 -0700511 char *vlist = NULL; /* If non-NULL, we used vmalloc() */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700512
513 if (size) {
514 if (size > XATTR_LIST_MAX)
515 size = XATTR_LIST_MAX;
Dave Jones703bf2d2012-04-05 14:25:06 -0700516 klist = kmalloc(size, __GFP_NOWARN | GFP_KERNEL);
Andrew Morton0d08d7b2012-04-05 14:25:07 -0700517 if (!klist) {
518 vlist = vmalloc(size);
519 if (!vlist)
520 return -ENOMEM;
521 klist = vlist;
522 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700523 }
524
Bill Nottingham659564c2006-10-09 16:10:48 -0400525 error = vfs_listxattr(d, klist, size);
Stephen Smalleyf549d6c2005-09-03 15:55:18 -0700526 if (error > 0) {
527 if (size && copy_to_user(list, klist, error))
528 error = -EFAULT;
529 } else if (error == -ERANGE && size >= XATTR_LIST_MAX) {
530 /* The file system tried to returned a list bigger
531 than XATTR_LIST_MAX bytes. Not possible. */
532 error = -E2BIG;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533 }
Andrew Morton0d08d7b2012-04-05 14:25:07 -0700534 if (vlist)
535 vfree(vlist);
536 else
537 kfree(klist);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700538 return error;
539}
540
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100541SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list,
542 size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700543{
Al Viro2d8f3032008-07-22 09:59:21 -0400544 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700545 ssize_t error;
546
Al Viro2d8f3032008-07-22 09:59:21 -0400547 error = user_path(pathname, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700548 if (error)
549 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400550 error = listxattr(path.dentry, list, size);
551 path_put(&path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700552 return error;
553}
554
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100555SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list,
556 size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700557{
Al Viro2d8f3032008-07-22 09:59:21 -0400558 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700559 ssize_t error;
560
Al Viro2d8f3032008-07-22 09:59:21 -0400561 error = user_lpath(pathname, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700562 if (error)
563 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400564 error = listxattr(path.dentry, list, size);
565 path_put(&path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566 return error;
567}
568
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100569SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570{
Al Viro7449af12012-04-21 18:41:25 -0400571 int fput_needed;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700572 struct file *f;
573 ssize_t error = -EBADF;
574
Al Viro7449af12012-04-21 18:41:25 -0400575 f = fget_light(fd, &fput_needed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700576 if (!f)
577 return error;
Al Viro5a190ae2007-06-07 12:19:32 -0400578 audit_inode(NULL, f->f_path.dentry);
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800579 error = listxattr(f->f_path.dentry, list, size);
Al Viro7449af12012-04-21 18:41:25 -0400580 fput_light(f, fput_needed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700581 return error;
582}
583
584/*
585 * Extended attribute REMOVE operations
586 */
587static long
David Howells8f0cfa52008-04-29 00:59:41 -0700588removexattr(struct dentry *d, const char __user *name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589{
590 int error;
591 char kname[XATTR_NAME_MAX + 1];
592
593 error = strncpy_from_user(kname, name, sizeof(kname));
594 if (error == 0 || error == sizeof(kname))
595 error = -ERANGE;
596 if (error < 0)
597 return error;
598
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800599 return vfs_removexattr(d, kname);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700600}
601
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100602SYSCALL_DEFINE2(removexattr, const char __user *, pathname,
603 const char __user *, name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700604{
Al Viro2d8f3032008-07-22 09:59:21 -0400605 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700606 int error;
607
Al Viro2d8f3032008-07-22 09:59:21 -0400608 error = user_path(pathname, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700609 if (error)
610 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400611 error = mnt_want_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800612 if (!error) {
Al Viro2d8f3032008-07-22 09:59:21 -0400613 error = removexattr(path.dentry, name);
614 mnt_drop_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800615 }
Al Viro2d8f3032008-07-22 09:59:21 -0400616 path_put(&path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700617 return error;
618}
619
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100620SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname,
621 const char __user *, name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700622{
Al Viro2d8f3032008-07-22 09:59:21 -0400623 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700624 int error;
625
Al Viro2d8f3032008-07-22 09:59:21 -0400626 error = user_lpath(pathname, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700627 if (error)
628 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400629 error = mnt_want_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800630 if (!error) {
Al Viro2d8f3032008-07-22 09:59:21 -0400631 error = removexattr(path.dentry, name);
632 mnt_drop_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800633 }
Al Viro2d8f3032008-07-22 09:59:21 -0400634 path_put(&path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635 return error;
636}
637
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100638SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700639{
Al Viro7449af12012-04-21 18:41:25 -0400640 int fput_needed;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641 struct file *f;
Amy Griffis73241cc2005-11-03 16:00:25 +0000642 struct dentry *dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700643 int error = -EBADF;
644
Al Viro7449af12012-04-21 18:41:25 -0400645 f = fget_light(fd, &fput_needed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700646 if (!f)
647 return error;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800648 dentry = f->f_path.dentry;
Al Viro5a190ae2007-06-07 12:19:32 -0400649 audit_inode(NULL, dentry);
npiggin@suse.de96029c42009-04-26 20:25:55 +1000650 error = mnt_want_write_file(f);
Dave Hansen18f335a2008-02-15 14:37:38 -0800651 if (!error) {
652 error = removexattr(dentry, name);
Al Viro2a79f172011-12-09 08:06:57 -0500653 mnt_drop_write_file(f);
Dave Hansen18f335a2008-02-15 14:37:38 -0800654 }
Al Viro7449af12012-04-21 18:41:25 -0400655 fput_light(f, fput_needed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700656 return error;
657}
658
659
660static const char *
661strcmp_prefix(const char *a, const char *a_prefix)
662{
663 while (*a_prefix && *a == *a_prefix) {
664 a++;
665 a_prefix++;
666 }
667 return *a_prefix ? NULL : a;
668}
669
670/*
671 * In order to implement different sets of xattr operations for each xattr
672 * prefix with the generic xattr API, a filesystem should create a
673 * null-terminated array of struct xattr_handler (one for each prefix) and
674 * hang a pointer to it off of the s_xattr field of the superblock.
675 *
676 * The generic_fooxattr() functions will use this list to dispatch xattr
677 * operations to the correct xattr_handler.
678 */
679#define for_each_xattr_handler(handlers, handler) \
680 for ((handler) = *(handlers)++; \
681 (handler) != NULL; \
682 (handler) = *(handlers)++)
683
684/*
685 * Find the xattr_handler with the matching prefix.
686 */
Stephen Hemmingerbb435452010-05-13 17:53:14 -0700687static const struct xattr_handler *
688xattr_resolve_name(const struct xattr_handler **handlers, const char **name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700689{
Stephen Hemmingerbb435452010-05-13 17:53:14 -0700690 const struct xattr_handler *handler;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700691
692 if (!*name)
693 return NULL;
694
695 for_each_xattr_handler(handlers, handler) {
696 const char *n = strcmp_prefix(*name, handler->prefix);
697 if (n) {
698 *name = n;
699 break;
700 }
701 }
702 return handler;
703}
704
705/*
706 * Find the handler for the prefix and dispatch its get() operation.
707 */
708ssize_t
709generic_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size)
710{
Stephen Hemmingerbb435452010-05-13 17:53:14 -0700711 const struct xattr_handler *handler;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700712
Christoph Hellwig431547b2009-11-13 09:52:56 +0000713 handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700714 if (!handler)
715 return -EOPNOTSUPP;
Christoph Hellwig431547b2009-11-13 09:52:56 +0000716 return handler->get(dentry, name, buffer, size, handler->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700717}
718
719/*
720 * Combine the results of the list() operation from every xattr_handler in the
721 * list.
722 */
723ssize_t
724generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
725{
Stephen Hemmingerbb435452010-05-13 17:53:14 -0700726 const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700727 unsigned int size = 0;
728
729 if (!buffer) {
Christoph Hellwig431547b2009-11-13 09:52:56 +0000730 for_each_xattr_handler(handlers, handler) {
731 size += handler->list(dentry, NULL, 0, NULL, 0,
732 handler->flags);
733 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700734 } else {
735 char *buf = buffer;
736
737 for_each_xattr_handler(handlers, handler) {
Christoph Hellwig431547b2009-11-13 09:52:56 +0000738 size = handler->list(dentry, buf, buffer_size,
739 NULL, 0, handler->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740 if (size > buffer_size)
741 return -ERANGE;
742 buf += size;
743 buffer_size -= size;
744 }
745 size = buf - buffer;
746 }
747 return size;
748}
749
750/*
751 * Find the handler for the prefix and dispatch its set() operation.
752 */
753int
754generic_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags)
755{
Stephen Hemmingerbb435452010-05-13 17:53:14 -0700756 const struct xattr_handler *handler;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700757
758 if (size == 0)
759 value = ""; /* empty EA, do not remove */
Christoph Hellwig431547b2009-11-13 09:52:56 +0000760 handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700761 if (!handler)
762 return -EOPNOTSUPP;
Jan Karadf7e1302011-04-20 20:30:40 +0200763 return handler->set(dentry, name, value, size, flags, handler->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764}
765
766/*
767 * Find the handler for the prefix and dispatch its set() operation to remove
768 * any associated extended attribute.
769 */
770int
771generic_removexattr(struct dentry *dentry, const char *name)
772{
Stephen Hemmingerbb435452010-05-13 17:53:14 -0700773 const struct xattr_handler *handler;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700774
Christoph Hellwig431547b2009-11-13 09:52:56 +0000775 handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700776 if (!handler)
777 return -EOPNOTSUPP;
Christoph Hellwig431547b2009-11-13 09:52:56 +0000778 return handler->set(dentry, name, NULL, 0,
779 XATTR_REPLACE, handler->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780}
781
782EXPORT_SYMBOL(generic_getxattr);
783EXPORT_SYMBOL(generic_listxattr);
784EXPORT_SYMBOL(generic_setxattr);
785EXPORT_SYMBOL(generic_removexattr);