blob: 4d45b7189e7eaa352da0567b8fe4a2d1b738c999 [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;
Sasha Levin779302e2012-07-30 14:39:13 -0700430 void *vvalue = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700431 char kname[XATTR_NAME_MAX + 1];
432
433 error = strncpy_from_user(kname, name, sizeof(kname));
434 if (error == 0 || error == sizeof(kname))
435 error = -ERANGE;
436 if (error < 0)
437 return error;
438
439 if (size) {
440 if (size > XATTR_SIZE_MAX)
441 size = XATTR_SIZE_MAX;
Sasha Levin779302e2012-07-30 14:39:13 -0700442 kvalue = kzalloc(size, GFP_KERNEL | __GFP_NOWARN);
443 if (!kvalue) {
444 vvalue = vmalloc(size);
445 if (!vvalue)
446 return -ENOMEM;
447 kvalue = vvalue;
448 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700449 }
450
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800451 error = vfs_getxattr(d, kname, kvalue, size);
Stephen Smalleyf549d6c2005-09-03 15:55:18 -0700452 if (error > 0) {
453 if (size && copy_to_user(value, kvalue, error))
454 error = -EFAULT;
455 } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) {
456 /* The file system tried to returned a value bigger
457 than XATTR_SIZE_MAX bytes. Not possible. */
458 error = -E2BIG;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700459 }
Sasha Levin779302e2012-07-30 14:39:13 -0700460 if (vvalue)
461 vfree(vvalue);
462 else
463 kfree(kvalue);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 return error;
465}
466
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100467SYSCALL_DEFINE4(getxattr, const char __user *, pathname,
468 const char __user *, name, void __user *, value, size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469{
Al Viro2d8f3032008-07-22 09:59:21 -0400470 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471 ssize_t error;
472
Al Viro2d8f3032008-07-22 09:59:21 -0400473 error = user_path(pathname, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700474 if (error)
475 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400476 error = getxattr(path.dentry, name, value, size);
477 path_put(&path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478 return error;
479}
480
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100481SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname,
482 const char __user *, name, void __user *, value, size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700483{
Al Viro2d8f3032008-07-22 09:59:21 -0400484 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485 ssize_t error;
486
Al Viro2d8f3032008-07-22 09:59:21 -0400487 error = user_lpath(pathname, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700488 if (error)
489 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400490 error = getxattr(path.dentry, name, value, size);
491 path_put(&path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700492 return error;
493}
494
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100495SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name,
496 void __user *, value, size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497{
Al Viro7449af12012-04-21 18:41:25 -0400498 int fput_needed;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700499 struct file *f;
500 ssize_t error = -EBADF;
501
Al Viro7449af12012-04-21 18:41:25 -0400502 f = fget_light(fd, &fput_needed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503 if (!f)
504 return error;
Al Viro5a190ae2007-06-07 12:19:32 -0400505 audit_inode(NULL, f->f_path.dentry);
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800506 error = getxattr(f->f_path.dentry, name, value, size);
Al Viro7449af12012-04-21 18:41:25 -0400507 fput_light(f, fput_needed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508 return error;
509}
510
511/*
512 * Extended attribute LIST operations
513 */
514static ssize_t
515listxattr(struct dentry *d, char __user *list, size_t size)
516{
517 ssize_t error;
518 char *klist = NULL;
Andrew Morton0d08d7b2012-04-05 14:25:07 -0700519 char *vlist = NULL; /* If non-NULL, we used vmalloc() */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520
521 if (size) {
522 if (size > XATTR_LIST_MAX)
523 size = XATTR_LIST_MAX;
Dave Jones703bf2d2012-04-05 14:25:06 -0700524 klist = kmalloc(size, __GFP_NOWARN | GFP_KERNEL);
Andrew Morton0d08d7b2012-04-05 14:25:07 -0700525 if (!klist) {
526 vlist = vmalloc(size);
527 if (!vlist)
528 return -ENOMEM;
529 klist = vlist;
530 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700531 }
532
Bill Nottingham659564c2006-10-09 16:10:48 -0400533 error = vfs_listxattr(d, klist, size);
Stephen Smalleyf549d6c2005-09-03 15:55:18 -0700534 if (error > 0) {
535 if (size && copy_to_user(list, klist, error))
536 error = -EFAULT;
537 } else if (error == -ERANGE && size >= XATTR_LIST_MAX) {
538 /* The file system tried to returned a list bigger
539 than XATTR_LIST_MAX bytes. Not possible. */
540 error = -E2BIG;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700541 }
Andrew Morton0d08d7b2012-04-05 14:25:07 -0700542 if (vlist)
543 vfree(vlist);
544 else
545 kfree(klist);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700546 return error;
547}
548
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100549SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list,
550 size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700551{
Al Viro2d8f3032008-07-22 09:59:21 -0400552 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553 ssize_t error;
554
Al Viro2d8f3032008-07-22 09:59:21 -0400555 error = user_path(pathname, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556 if (error)
557 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400558 error = listxattr(path.dentry, list, size);
559 path_put(&path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700560 return error;
561}
562
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100563SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list,
564 size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700565{
Al Viro2d8f3032008-07-22 09:59:21 -0400566 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700567 ssize_t error;
568
Al Viro2d8f3032008-07-22 09:59:21 -0400569 error = user_lpath(pathname, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570 if (error)
571 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400572 error = listxattr(path.dentry, list, size);
573 path_put(&path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700574 return error;
575}
576
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100577SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700578{
Al Viro7449af12012-04-21 18:41:25 -0400579 int fput_needed;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700580 struct file *f;
581 ssize_t error = -EBADF;
582
Al Viro7449af12012-04-21 18:41:25 -0400583 f = fget_light(fd, &fput_needed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584 if (!f)
585 return error;
Al Viro5a190ae2007-06-07 12:19:32 -0400586 audit_inode(NULL, f->f_path.dentry);
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800587 error = listxattr(f->f_path.dentry, list, size);
Al Viro7449af12012-04-21 18:41:25 -0400588 fput_light(f, fput_needed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700589 return error;
590}
591
592/*
593 * Extended attribute REMOVE operations
594 */
595static long
David Howells8f0cfa52008-04-29 00:59:41 -0700596removexattr(struct dentry *d, const char __user *name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597{
598 int error;
599 char kname[XATTR_NAME_MAX + 1];
600
601 error = strncpy_from_user(kname, name, sizeof(kname));
602 if (error == 0 || error == sizeof(kname))
603 error = -ERANGE;
604 if (error < 0)
605 return error;
606
Christoph Hellwig5be196e2006-01-09 20:51:55 -0800607 return vfs_removexattr(d, kname);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700608}
609
Heiko Carstens64fd1de2009-01-14 14:14:14 +0100610SYSCALL_DEFINE2(removexattr, const char __user *, pathname,
611 const char __user *, name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612{
Al Viro2d8f3032008-07-22 09:59:21 -0400613 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614 int error;
615
Al Viro2d8f3032008-07-22 09:59:21 -0400616 error = user_path(pathname, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700617 if (error)
618 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400619 error = mnt_want_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800620 if (!error) {
Al Viro2d8f3032008-07-22 09:59:21 -0400621 error = removexattr(path.dentry, name);
622 mnt_drop_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800623 }
Al Viro2d8f3032008-07-22 09:59:21 -0400624 path_put(&path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700625 return error;
626}
627
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100628SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname,
629 const char __user *, name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700630{
Al Viro2d8f3032008-07-22 09:59:21 -0400631 struct path path;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700632 int error;
633
Al Viro2d8f3032008-07-22 09:59:21 -0400634 error = user_lpath(pathname, &path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700635 if (error)
636 return error;
Al Viro2d8f3032008-07-22 09:59:21 -0400637 error = mnt_want_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800638 if (!error) {
Al Viro2d8f3032008-07-22 09:59:21 -0400639 error = removexattr(path.dentry, name);
640 mnt_drop_write(path.mnt);
Dave Hansen18f335a2008-02-15 14:37:38 -0800641 }
Al Viro2d8f3032008-07-22 09:59:21 -0400642 path_put(&path);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700643 return error;
644}
645
Heiko Carstens6a6160a2009-01-14 14:14:15 +0100646SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647{
Al Viro7449af12012-04-21 18:41:25 -0400648 int fput_needed;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700649 struct file *f;
Amy Griffis73241cc2005-11-03 16:00:25 +0000650 struct dentry *dentry;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700651 int error = -EBADF;
652
Al Viro7449af12012-04-21 18:41:25 -0400653 f = fget_light(fd, &fput_needed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654 if (!f)
655 return error;
Josef "Jeff" Sipek0f7fc9e2006-12-08 02:36:35 -0800656 dentry = f->f_path.dentry;
Al Viro5a190ae2007-06-07 12:19:32 -0400657 audit_inode(NULL, dentry);
npiggin@suse.de96029c42009-04-26 20:25:55 +1000658 error = mnt_want_write_file(f);
Dave Hansen18f335a2008-02-15 14:37:38 -0800659 if (!error) {
660 error = removexattr(dentry, name);
Al Viro2a79f172011-12-09 08:06:57 -0500661 mnt_drop_write_file(f);
Dave Hansen18f335a2008-02-15 14:37:38 -0800662 }
Al Viro7449af12012-04-21 18:41:25 -0400663 fput_light(f, fput_needed);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700664 return error;
665}
666
667
668static const char *
669strcmp_prefix(const char *a, const char *a_prefix)
670{
671 while (*a_prefix && *a == *a_prefix) {
672 a++;
673 a_prefix++;
674 }
675 return *a_prefix ? NULL : a;
676}
677
678/*
679 * In order to implement different sets of xattr operations for each xattr
680 * prefix with the generic xattr API, a filesystem should create a
681 * null-terminated array of struct xattr_handler (one for each prefix) and
682 * hang a pointer to it off of the s_xattr field of the superblock.
683 *
684 * The generic_fooxattr() functions will use this list to dispatch xattr
685 * operations to the correct xattr_handler.
686 */
687#define for_each_xattr_handler(handlers, handler) \
688 for ((handler) = *(handlers)++; \
689 (handler) != NULL; \
690 (handler) = *(handlers)++)
691
692/*
693 * Find the xattr_handler with the matching prefix.
694 */
Stephen Hemmingerbb435452010-05-13 17:53:14 -0700695static const struct xattr_handler *
696xattr_resolve_name(const struct xattr_handler **handlers, const char **name)
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
700 if (!*name)
701 return NULL;
702
703 for_each_xattr_handler(handlers, handler) {
704 const char *n = strcmp_prefix(*name, handler->prefix);
705 if (n) {
706 *name = n;
707 break;
708 }
709 }
710 return handler;
711}
712
713/*
714 * Find the handler for the prefix and dispatch its get() operation.
715 */
716ssize_t
717generic_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size)
718{
Stephen Hemmingerbb435452010-05-13 17:53:14 -0700719 const struct xattr_handler *handler;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700720
Christoph Hellwig431547b2009-11-13 09:52:56 +0000721 handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700722 if (!handler)
723 return -EOPNOTSUPP;
Christoph Hellwig431547b2009-11-13 09:52:56 +0000724 return handler->get(dentry, name, buffer, size, handler->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700725}
726
727/*
728 * Combine the results of the list() operation from every xattr_handler in the
729 * list.
730 */
731ssize_t
732generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
733{
Stephen Hemmingerbb435452010-05-13 17:53:14 -0700734 const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700735 unsigned int size = 0;
736
737 if (!buffer) {
Christoph Hellwig431547b2009-11-13 09:52:56 +0000738 for_each_xattr_handler(handlers, handler) {
739 size += handler->list(dentry, NULL, 0, NULL, 0,
740 handler->flags);
741 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700742 } else {
743 char *buf = buffer;
744
745 for_each_xattr_handler(handlers, handler) {
Christoph Hellwig431547b2009-11-13 09:52:56 +0000746 size = handler->list(dentry, buf, buffer_size,
747 NULL, 0, handler->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700748 if (size > buffer_size)
749 return -ERANGE;
750 buf += size;
751 buffer_size -= size;
752 }
753 size = buf - buffer;
754 }
755 return size;
756}
757
758/*
759 * Find the handler for the prefix and dispatch its set() operation.
760 */
761int
762generic_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags)
763{
Stephen Hemmingerbb435452010-05-13 17:53:14 -0700764 const struct xattr_handler *handler;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765
766 if (size == 0)
767 value = ""; /* empty EA, do not remove */
Christoph Hellwig431547b2009-11-13 09:52:56 +0000768 handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700769 if (!handler)
770 return -EOPNOTSUPP;
Jan Karadf7e1302011-04-20 20:30:40 +0200771 return handler->set(dentry, name, value, size, flags, handler->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700772}
773
774/*
775 * Find the handler for the prefix and dispatch its set() operation to remove
776 * any associated extended attribute.
777 */
778int
779generic_removexattr(struct dentry *dentry, const char *name)
780{
Stephen Hemmingerbb435452010-05-13 17:53:14 -0700781 const struct xattr_handler *handler;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700782
Christoph Hellwig431547b2009-11-13 09:52:56 +0000783 handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700784 if (!handler)
785 return -EOPNOTSUPP;
Christoph Hellwig431547b2009-11-13 09:52:56 +0000786 return handler->set(dentry, name, NULL, 0,
787 XATTR_REPLACE, handler->flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700788}
789
790EXPORT_SYMBOL(generic_getxattr);
791EXPORT_SYMBOL(generic_listxattr);
792EXPORT_SYMBOL(generic_setxattr);
793EXPORT_SYMBOL(generic_removexattr);