Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
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> | |
1da177e4 LT |
12 | #include <linux/file.h> |
13 | #include <linux/xattr.h> | |
18f335af | 14 | #include <linux/mount.h> |
1da177e4 LT |
15 | #include <linux/namei.h> |
16 | #include <linux/security.h> | |
c7b87de2 | 17 | #include <linux/evm.h> |
1da177e4 | 18 | #include <linux/syscalls.h> |
630d9c47 | 19 | #include <linux/export.h> |
0eeca283 | 20 | #include <linux/fsnotify.h> |
73241ccc | 21 | #include <linux/audit.h> |
0d08d7b7 | 22 | #include <linux/vmalloc.h> |
2f6f0654 | 23 | #include <linux/posix_acl_xattr.h> |
1da177e4 | 24 | |
0d08d7b7 | 25 | #include <asm/uaccess.h> |
5be196e5 | 26 | |
e0ad7b07 | 27 | /* |
28 | * Check permissions for extended attribute access. This is a bit complicated | |
29 | * because different namespaces have very different rules. | |
30 | */ | |
31 | static int | |
32 | xattr_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) { | |
e0ad7b07 | 39 | 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 | /* | |
55b23bde | 52 | * The trusted.* namespace can only be accessed by privileged users. |
e0ad7b07 | 53 | */ |
55b23bde AG |
54 | 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 | } | |
e0ad7b07 | 59 | |
55b23bde AG |
60 | /* |
61 | * In the user.* namespace, only regular files and directories can have | |
f1f2d871 | 62 | * extended attributes. For sticky directories, only the owner and |
55b23bde | 63 | * privileged users can write attributes. |
f1f2d871 | 64 | */ |
e0ad7b07 | 65 | if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) { |
f1f2d871 | 66 | if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode)) |
55b23bde | 67 | return (mask & MAY_WRITE) ? -EPERM : -ENODATA; |
f1f2d871 | 68 | if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) && |
2e149670 | 69 | (mask & MAY_WRITE) && !inode_owner_or_capable(inode)) |
e0ad7b07 | 70 | return -EPERM; |
71 | } | |
72 | ||
f419a2e3 | 73 | return inode_permission(inode, mask); |
e0ad7b07 | 74 | } |
75 | ||
b1ab7e4b DQ |
76 | /** |
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 | */ | |
92 | int __vfs_setxattr_noperm(struct dentry *dentry, const char *name, | |
93 | const void *value, size_t size, int flags) | |
5be196e5 CH |
94 | { |
95 | struct inode *inode = dentry->d_inode; | |
b1ab7e4b | 96 | int error = -EOPNOTSUPP; |
69b45732 AK |
97 | int issec = !strncmp(name, XATTR_SECURITY_PREFIX, |
98 | XATTR_SECURITY_PREFIX_LEN); | |
e0ad7b07 | 99 | |
69b45732 AK |
100 | if (issec) |
101 | inode->i_flags &= ~S_NOSEC; | |
5be196e5 CH |
102 | if (inode->i_op->setxattr) { |
103 | error = inode->i_op->setxattr(dentry, name, value, size, flags); | |
104 | if (!error) { | |
105 | fsnotify_xattr(dentry); | |
106 | security_inode_post_setxattr(dentry, name, value, | |
107 | size, flags); | |
108 | } | |
69b45732 | 109 | } else if (issec) { |
e0ad7b07 | 110 | const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; |
5be196e5 CH |
111 | error = security_inode_setsecurity(inode, suffix, value, |
112 | size, flags); | |
113 | if (!error) | |
114 | fsnotify_xattr(dentry); | |
115 | } | |
b1ab7e4b DQ |
116 | |
117 | return error; | |
118 | } | |
119 | ||
120 | ||
121 | int | |
122 | vfs_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 | ||
132 | mutex_lock(&inode->i_mutex); | |
133 | 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 | ||
5be196e5 CH |
139 | out: |
140 | mutex_unlock(&inode->i_mutex); | |
141 | return error; | |
142 | } | |
143 | EXPORT_SYMBOL_GPL(vfs_setxattr); | |
144 | ||
42492594 DQ |
145 | ssize_t |
146 | xattr_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); | |
165 | out: | |
166 | security_release_secctx(buffer, len); | |
167 | out_noalloc: | |
168 | return len; | |
169 | } | |
170 | EXPORT_SYMBOL_GPL(xattr_getsecurity); | |
171 | ||
1601fbad MZ |
172 | /* |
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 | */ | |
180 | ssize_t | |
181 | vfs_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 | ||
195 | error = inode->i_op->getxattr(dentry, name, NULL, 0); | |
196 | 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 | ||
206 | error = inode->i_op->getxattr(dentry, name, value, error); | |
207 | *xattr_value = value; | |
208 | return error; | |
209 | } | |
210 | ||
211 | /* Compare an extended attribute value with the given value */ | |
212 | int vfs_xattr_cmp(struct dentry *dentry, const char *xattr_name, | |
213 | const char *value, size_t size, gfp_t flags) | |
214 | { | |
215 | char *xattr_value = NULL; | |
216 | int rc; | |
217 | ||
218 | rc = vfs_getxattr_alloc(dentry, xattr_name, &xattr_value, 0, flags); | |
219 | if (rc < 0) | |
220 | return rc; | |
221 | ||
222 | if ((rc != size) || (memcmp(xattr_value, value, rc) != 0)) | |
223 | rc = -EINVAL; | |
224 | else | |
225 | rc = 0; | |
226 | kfree(xattr_value); | |
227 | return rc; | |
228 | } | |
229 | ||
5be196e5 | 230 | ssize_t |
8f0cfa52 | 231 | vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size) |
5be196e5 CH |
232 | { |
233 | struct inode *inode = dentry->d_inode; | |
234 | int error; | |
235 | ||
e0ad7b07 | 236 | error = xattr_permission(inode, name, MAY_READ); |
237 | if (error) | |
238 | return error; | |
239 | ||
5be196e5 CH |
240 | error = security_inode_getxattr(dentry, name); |
241 | if (error) | |
242 | return error; | |
243 | ||
5be196e5 | 244 | if (!strncmp(name, XATTR_SECURITY_PREFIX, |
e0ad7b07 | 245 | XATTR_SECURITY_PREFIX_LEN)) { |
246 | const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; | |
42492594 | 247 | int ret = xattr_getsecurity(inode, suffix, value, size); |
5be196e5 CH |
248 | /* |
249 | * Only overwrite the return value if a security module | |
250 | * is actually active. | |
251 | */ | |
4bea5805 DQ |
252 | if (ret == -EOPNOTSUPP) |
253 | goto nolsm; | |
254 | return ret; | |
5be196e5 | 255 | } |
4bea5805 DQ |
256 | nolsm: |
257 | if (inode->i_op->getxattr) | |
258 | error = inode->i_op->getxattr(dentry, name, value, size); | |
259 | else | |
260 | error = -EOPNOTSUPP; | |
5be196e5 CH |
261 | |
262 | return error; | |
263 | } | |
264 | EXPORT_SYMBOL_GPL(vfs_getxattr); | |
265 | ||
659564c8 BN |
266 | ssize_t |
267 | vfs_listxattr(struct dentry *d, char *list, size_t size) | |
268 | { | |
269 | ssize_t error; | |
270 | ||
271 | error = security_inode_listxattr(d); | |
272 | if (error) | |
273 | return error; | |
274 | error = -EOPNOTSUPP; | |
acfa4380 | 275 | if (d->d_inode->i_op->listxattr) { |
659564c8 BN |
276 | error = d->d_inode->i_op->listxattr(d, list, size); |
277 | } else { | |
278 | error = security_inode_listsecurity(d->d_inode, list, size); | |
279 | if (size && error > size) | |
280 | error = -ERANGE; | |
281 | } | |
282 | return error; | |
283 | } | |
284 | EXPORT_SYMBOL_GPL(vfs_listxattr); | |
285 | ||
5be196e5 | 286 | int |
8f0cfa52 | 287 | vfs_removexattr(struct dentry *dentry, const char *name) |
5be196e5 CH |
288 | { |
289 | struct inode *inode = dentry->d_inode; | |
290 | int error; | |
291 | ||
292 | if (!inode->i_op->removexattr) | |
293 | return -EOPNOTSUPP; | |
294 | ||
e0ad7b07 | 295 | error = xattr_permission(inode, name, MAY_WRITE); |
296 | if (error) | |
297 | return error; | |
298 | ||
5be196e5 CH |
299 | error = security_inode_removexattr(dentry, name); |
300 | if (error) | |
301 | return error; | |
302 | ||
303 | mutex_lock(&inode->i_mutex); | |
304 | error = inode->i_op->removexattr(dentry, name); | |
305 | mutex_unlock(&inode->i_mutex); | |
306 | ||
c7b87de2 | 307 | if (!error) { |
5be196e5 | 308 | fsnotify_xattr(dentry); |
c7b87de2 MZ |
309 | evm_inode_post_removexattr(dentry, name); |
310 | } | |
5be196e5 CH |
311 | return error; |
312 | } | |
313 | EXPORT_SYMBOL_GPL(vfs_removexattr); | |
314 | ||
315 | ||
1da177e4 LT |
316 | /* |
317 | * Extended attribute SET operations | |
318 | */ | |
319 | static long | |
8f0cfa52 | 320 | setxattr(struct dentry *d, const char __user *name, const void __user *value, |
1da177e4 LT |
321 | size_t size, int flags) |
322 | { | |
323 | int error; | |
324 | void *kvalue = NULL; | |
44c82498 | 325 | void *vvalue = NULL; /* If non-NULL, we used vmalloc() */ |
1da177e4 LT |
326 | char kname[XATTR_NAME_MAX + 1]; |
327 | ||
328 | if (flags & ~(XATTR_CREATE|XATTR_REPLACE)) | |
329 | return -EINVAL; | |
330 | ||
331 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
332 | if (error == 0 || error == sizeof(kname)) | |
333 | error = -ERANGE; | |
334 | if (error < 0) | |
335 | return error; | |
336 | ||
337 | if (size) { | |
338 | if (size > XATTR_SIZE_MAX) | |
339 | return -E2BIG; | |
44c82498 AM |
340 | kvalue = kmalloc(size, GFP_KERNEL | __GFP_NOWARN); |
341 | if (!kvalue) { | |
342 | vvalue = vmalloc(size); | |
343 | if (!vvalue) | |
344 | return -ENOMEM; | |
345 | kvalue = vvalue; | |
346 | } | |
347 | if (copy_from_user(kvalue, value, size)) { | |
348 | error = -EFAULT; | |
349 | goto out; | |
350 | } | |
2f6f0654 EB |
351 | if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) || |
352 | (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)) | |
353 | posix_acl_fix_xattr_from_user(kvalue, size); | |
1da177e4 LT |
354 | } |
355 | ||
5be196e5 | 356 | error = vfs_setxattr(d, kname, kvalue, size, flags); |
44c82498 AM |
357 | out: |
358 | if (vvalue) | |
359 | vfree(vvalue); | |
360 | else | |
361 | kfree(kvalue); | |
1da177e4 LT |
362 | return error; |
363 | } | |
364 | ||
64fd1de3 HC |
365 | SYSCALL_DEFINE5(setxattr, const char __user *, pathname, |
366 | const char __user *, name, const void __user *, value, | |
367 | size_t, size, int, flags) | |
1da177e4 | 368 | { |
2d8f3038 | 369 | struct path path; |
1da177e4 LT |
370 | int error; |
371 | ||
2d8f3038 | 372 | error = user_path(pathname, &path); |
1da177e4 LT |
373 | if (error) |
374 | return error; | |
2d8f3038 | 375 | error = mnt_want_write(path.mnt); |
18f335af | 376 | if (!error) { |
2d8f3038 AV |
377 | error = setxattr(path.dentry, name, value, size, flags); |
378 | mnt_drop_write(path.mnt); | |
18f335af | 379 | } |
2d8f3038 | 380 | path_put(&path); |
1da177e4 LT |
381 | return error; |
382 | } | |
383 | ||
64fd1de3 HC |
384 | SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname, |
385 | const char __user *, name, const void __user *, value, | |
386 | size_t, size, int, flags) | |
1da177e4 | 387 | { |
2d8f3038 | 388 | struct path path; |
1da177e4 LT |
389 | int error; |
390 | ||
2d8f3038 | 391 | error = user_lpath(pathname, &path); |
1da177e4 LT |
392 | if (error) |
393 | return error; | |
2d8f3038 | 394 | error = mnt_want_write(path.mnt); |
18f335af | 395 | if (!error) { |
2d8f3038 AV |
396 | error = setxattr(path.dentry, name, value, size, flags); |
397 | mnt_drop_write(path.mnt); | |
18f335af | 398 | } |
2d8f3038 | 399 | path_put(&path); |
1da177e4 LT |
400 | return error; |
401 | } | |
402 | ||
64fd1de3 HC |
403 | SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name, |
404 | const void __user *,value, size_t, size, int, flags) | |
1da177e4 | 405 | { |
7449af1e | 406 | int fput_needed; |
1da177e4 | 407 | struct file *f; |
73241ccc | 408 | struct dentry *dentry; |
1da177e4 LT |
409 | int error = -EBADF; |
410 | ||
7449af1e | 411 | f = fget_light(fd, &fput_needed); |
1da177e4 LT |
412 | if (!f) |
413 | return error; | |
0f7fc9e4 | 414 | dentry = f->f_path.dentry; |
5a190ae6 | 415 | audit_inode(NULL, dentry); |
96029c4e | 416 | error = mnt_want_write_file(f); |
18f335af DH |
417 | if (!error) { |
418 | error = setxattr(dentry, name, value, size, flags); | |
2a79f17e | 419 | mnt_drop_write_file(f); |
18f335af | 420 | } |
7449af1e | 421 | fput_light(f, fput_needed); |
1da177e4 LT |
422 | return error; |
423 | } | |
424 | ||
425 | /* | |
426 | * Extended attribute GET operations | |
427 | */ | |
428 | static ssize_t | |
8f0cfa52 DH |
429 | getxattr(struct dentry *d, const char __user *name, void __user *value, |
430 | size_t size) | |
1da177e4 LT |
431 | { |
432 | ssize_t error; | |
433 | void *kvalue = NULL; | |
779302e6 | 434 | void *vvalue = NULL; |
1da177e4 LT |
435 | char kname[XATTR_NAME_MAX + 1]; |
436 | ||
437 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
438 | if (error == 0 || error == sizeof(kname)) | |
439 | error = -ERANGE; | |
440 | if (error < 0) | |
441 | return error; | |
442 | ||
443 | if (size) { | |
444 | if (size > XATTR_SIZE_MAX) | |
445 | size = XATTR_SIZE_MAX; | |
779302e6 SL |
446 | kvalue = kzalloc(size, GFP_KERNEL | __GFP_NOWARN); |
447 | if (!kvalue) { | |
448 | vvalue = vmalloc(size); | |
449 | if (!vvalue) | |
450 | return -ENOMEM; | |
451 | kvalue = vvalue; | |
452 | } | |
1da177e4 LT |
453 | } |
454 | ||
5be196e5 | 455 | error = vfs_getxattr(d, kname, kvalue, size); |
f549d6c1 | 456 | if (error > 0) { |
2f6f0654 EB |
457 | if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) || |
458 | (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)) | |
459 | posix_acl_fix_xattr_to_user(kvalue, size); | |
f549d6c1 SS |
460 | if (size && copy_to_user(value, kvalue, error)) |
461 | error = -EFAULT; | |
462 | } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) { | |
463 | /* The file system tried to returned a value bigger | |
464 | than XATTR_SIZE_MAX bytes. Not possible. */ | |
465 | error = -E2BIG; | |
1da177e4 | 466 | } |
779302e6 SL |
467 | if (vvalue) |
468 | vfree(vvalue); | |
469 | else | |
470 | kfree(kvalue); | |
1da177e4 LT |
471 | return error; |
472 | } | |
473 | ||
64fd1de3 HC |
474 | SYSCALL_DEFINE4(getxattr, const char __user *, pathname, |
475 | const char __user *, name, void __user *, value, size_t, size) | |
1da177e4 | 476 | { |
2d8f3038 | 477 | struct path path; |
1da177e4 LT |
478 | ssize_t error; |
479 | ||
2d8f3038 | 480 | error = user_path(pathname, &path); |
1da177e4 LT |
481 | if (error) |
482 | return error; | |
2d8f3038 AV |
483 | error = getxattr(path.dentry, name, value, size); |
484 | path_put(&path); | |
1da177e4 LT |
485 | return error; |
486 | } | |
487 | ||
64fd1de3 HC |
488 | SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname, |
489 | const char __user *, name, void __user *, value, size_t, size) | |
1da177e4 | 490 | { |
2d8f3038 | 491 | struct path path; |
1da177e4 LT |
492 | ssize_t error; |
493 | ||
2d8f3038 | 494 | error = user_lpath(pathname, &path); |
1da177e4 LT |
495 | if (error) |
496 | return error; | |
2d8f3038 AV |
497 | error = getxattr(path.dentry, name, value, size); |
498 | path_put(&path); | |
1da177e4 LT |
499 | return error; |
500 | } | |
501 | ||
64fd1de3 HC |
502 | SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name, |
503 | void __user *, value, size_t, size) | |
1da177e4 | 504 | { |
7449af1e | 505 | int fput_needed; |
1da177e4 LT |
506 | struct file *f; |
507 | ssize_t error = -EBADF; | |
508 | ||
7449af1e | 509 | f = fget_light(fd, &fput_needed); |
1da177e4 LT |
510 | if (!f) |
511 | return error; | |
5a190ae6 | 512 | audit_inode(NULL, f->f_path.dentry); |
0f7fc9e4 | 513 | error = getxattr(f->f_path.dentry, name, value, size); |
7449af1e | 514 | fput_light(f, fput_needed); |
1da177e4 LT |
515 | return error; |
516 | } | |
517 | ||
518 | /* | |
519 | * Extended attribute LIST operations | |
520 | */ | |
521 | static ssize_t | |
522 | listxattr(struct dentry *d, char __user *list, size_t size) | |
523 | { | |
524 | ssize_t error; | |
525 | char *klist = NULL; | |
0d08d7b7 | 526 | char *vlist = NULL; /* If non-NULL, we used vmalloc() */ |
1da177e4 LT |
527 | |
528 | if (size) { | |
529 | if (size > XATTR_LIST_MAX) | |
530 | size = XATTR_LIST_MAX; | |
703bf2d1 | 531 | klist = kmalloc(size, __GFP_NOWARN | GFP_KERNEL); |
0d08d7b7 AM |
532 | if (!klist) { |
533 | vlist = vmalloc(size); | |
534 | if (!vlist) | |
535 | return -ENOMEM; | |
536 | klist = vlist; | |
537 | } | |
1da177e4 LT |
538 | } |
539 | ||
659564c8 | 540 | error = vfs_listxattr(d, klist, size); |
f549d6c1 SS |
541 | if (error > 0) { |
542 | if (size && copy_to_user(list, klist, error)) | |
543 | error = -EFAULT; | |
544 | } else if (error == -ERANGE && size >= XATTR_LIST_MAX) { | |
545 | /* The file system tried to returned a list bigger | |
546 | than XATTR_LIST_MAX bytes. Not possible. */ | |
547 | error = -E2BIG; | |
1da177e4 | 548 | } |
0d08d7b7 AM |
549 | if (vlist) |
550 | vfree(vlist); | |
551 | else | |
552 | kfree(klist); | |
1da177e4 LT |
553 | return error; |
554 | } | |
555 | ||
64fd1de3 HC |
556 | SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list, |
557 | size_t, size) | |
1da177e4 | 558 | { |
2d8f3038 | 559 | struct path path; |
1da177e4 LT |
560 | ssize_t error; |
561 | ||
2d8f3038 | 562 | error = user_path(pathname, &path); |
1da177e4 LT |
563 | if (error) |
564 | return error; | |
2d8f3038 AV |
565 | error = listxattr(path.dentry, list, size); |
566 | path_put(&path); | |
1da177e4 LT |
567 | return error; |
568 | } | |
569 | ||
64fd1de3 HC |
570 | SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list, |
571 | size_t, size) | |
1da177e4 | 572 | { |
2d8f3038 | 573 | struct path path; |
1da177e4 LT |
574 | ssize_t error; |
575 | ||
2d8f3038 | 576 | error = user_lpath(pathname, &path); |
1da177e4 LT |
577 | if (error) |
578 | return error; | |
2d8f3038 AV |
579 | error = listxattr(path.dentry, list, size); |
580 | path_put(&path); | |
1da177e4 LT |
581 | return error; |
582 | } | |
583 | ||
64fd1de3 | 584 | SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size) |
1da177e4 | 585 | { |
7449af1e | 586 | int fput_needed; |
1da177e4 LT |
587 | struct file *f; |
588 | ssize_t error = -EBADF; | |
589 | ||
7449af1e | 590 | f = fget_light(fd, &fput_needed); |
1da177e4 LT |
591 | if (!f) |
592 | return error; | |
5a190ae6 | 593 | audit_inode(NULL, f->f_path.dentry); |
0f7fc9e4 | 594 | error = listxattr(f->f_path.dentry, list, size); |
7449af1e | 595 | fput_light(f, fput_needed); |
1da177e4 LT |
596 | return error; |
597 | } | |
598 | ||
599 | /* | |
600 | * Extended attribute REMOVE operations | |
601 | */ | |
602 | static long | |
8f0cfa52 | 603 | removexattr(struct dentry *d, const char __user *name) |
1da177e4 LT |
604 | { |
605 | int error; | |
606 | char kname[XATTR_NAME_MAX + 1]; | |
607 | ||
608 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
609 | if (error == 0 || error == sizeof(kname)) | |
610 | error = -ERANGE; | |
611 | if (error < 0) | |
612 | return error; | |
613 | ||
5be196e5 | 614 | return vfs_removexattr(d, kname); |
1da177e4 LT |
615 | } |
616 | ||
64fd1de3 HC |
617 | SYSCALL_DEFINE2(removexattr, const char __user *, pathname, |
618 | const char __user *, name) | |
1da177e4 | 619 | { |
2d8f3038 | 620 | struct path path; |
1da177e4 LT |
621 | int error; |
622 | ||
2d8f3038 | 623 | error = user_path(pathname, &path); |
1da177e4 LT |
624 | if (error) |
625 | return error; | |
2d8f3038 | 626 | error = mnt_want_write(path.mnt); |
18f335af | 627 | if (!error) { |
2d8f3038 AV |
628 | error = removexattr(path.dentry, name); |
629 | mnt_drop_write(path.mnt); | |
18f335af | 630 | } |
2d8f3038 | 631 | path_put(&path); |
1da177e4 LT |
632 | return error; |
633 | } | |
634 | ||
6a6160a7 HC |
635 | SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname, |
636 | const char __user *, name) | |
1da177e4 | 637 | { |
2d8f3038 | 638 | struct path path; |
1da177e4 LT |
639 | int error; |
640 | ||
2d8f3038 | 641 | error = user_lpath(pathname, &path); |
1da177e4 LT |
642 | if (error) |
643 | return error; | |
2d8f3038 | 644 | error = mnt_want_write(path.mnt); |
18f335af | 645 | if (!error) { |
2d8f3038 AV |
646 | error = removexattr(path.dentry, name); |
647 | mnt_drop_write(path.mnt); | |
18f335af | 648 | } |
2d8f3038 | 649 | path_put(&path); |
1da177e4 LT |
650 | return error; |
651 | } | |
652 | ||
6a6160a7 | 653 | SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name) |
1da177e4 | 654 | { |
7449af1e | 655 | int fput_needed; |
1da177e4 | 656 | struct file *f; |
73241ccc | 657 | struct dentry *dentry; |
1da177e4 LT |
658 | int error = -EBADF; |
659 | ||
7449af1e | 660 | f = fget_light(fd, &fput_needed); |
1da177e4 LT |
661 | if (!f) |
662 | return error; | |
0f7fc9e4 | 663 | dentry = f->f_path.dentry; |
5a190ae6 | 664 | audit_inode(NULL, dentry); |
96029c4e | 665 | error = mnt_want_write_file(f); |
18f335af DH |
666 | if (!error) { |
667 | error = removexattr(dentry, name); | |
2a79f17e | 668 | mnt_drop_write_file(f); |
18f335af | 669 | } |
7449af1e | 670 | fput_light(f, fput_needed); |
1da177e4 LT |
671 | return error; |
672 | } | |
673 | ||
674 | ||
675 | static const char * | |
676 | strcmp_prefix(const char *a, const char *a_prefix) | |
677 | { | |
678 | while (*a_prefix && *a == *a_prefix) { | |
679 | a++; | |
680 | a_prefix++; | |
681 | } | |
682 | return *a_prefix ? NULL : a; | |
683 | } | |
684 | ||
685 | /* | |
686 | * In order to implement different sets of xattr operations for each xattr | |
687 | * prefix with the generic xattr API, a filesystem should create a | |
688 | * null-terminated array of struct xattr_handler (one for each prefix) and | |
689 | * hang a pointer to it off of the s_xattr field of the superblock. | |
690 | * | |
691 | * The generic_fooxattr() functions will use this list to dispatch xattr | |
692 | * operations to the correct xattr_handler. | |
693 | */ | |
694 | #define for_each_xattr_handler(handlers, handler) \ | |
695 | for ((handler) = *(handlers)++; \ | |
696 | (handler) != NULL; \ | |
697 | (handler) = *(handlers)++) | |
698 | ||
699 | /* | |
700 | * Find the xattr_handler with the matching prefix. | |
701 | */ | |
bb435453 SH |
702 | static const struct xattr_handler * |
703 | xattr_resolve_name(const struct xattr_handler **handlers, const char **name) | |
1da177e4 | 704 | { |
bb435453 | 705 | const struct xattr_handler *handler; |
1da177e4 LT |
706 | |
707 | if (!*name) | |
708 | return NULL; | |
709 | ||
710 | for_each_xattr_handler(handlers, handler) { | |
711 | const char *n = strcmp_prefix(*name, handler->prefix); | |
712 | if (n) { | |
713 | *name = n; | |
714 | break; | |
715 | } | |
716 | } | |
717 | return handler; | |
718 | } | |
719 | ||
720 | /* | |
721 | * Find the handler for the prefix and dispatch its get() operation. | |
722 | */ | |
723 | ssize_t | |
724 | generic_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size) | |
725 | { | |
bb435453 | 726 | const struct xattr_handler *handler; |
1da177e4 | 727 | |
431547b3 | 728 | handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name); |
1da177e4 LT |
729 | if (!handler) |
730 | return -EOPNOTSUPP; | |
431547b3 | 731 | return handler->get(dentry, name, buffer, size, handler->flags); |
1da177e4 LT |
732 | } |
733 | ||
734 | /* | |
735 | * Combine the results of the list() operation from every xattr_handler in the | |
736 | * list. | |
737 | */ | |
738 | ssize_t | |
739 | generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) | |
740 | { | |
bb435453 | 741 | const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr; |
1da177e4 LT |
742 | unsigned int size = 0; |
743 | ||
744 | if (!buffer) { | |
431547b3 CH |
745 | for_each_xattr_handler(handlers, handler) { |
746 | size += handler->list(dentry, NULL, 0, NULL, 0, | |
747 | handler->flags); | |
748 | } | |
1da177e4 LT |
749 | } else { |
750 | char *buf = buffer; | |
751 | ||
752 | for_each_xattr_handler(handlers, handler) { | |
431547b3 CH |
753 | size = handler->list(dentry, buf, buffer_size, |
754 | NULL, 0, handler->flags); | |
1da177e4 LT |
755 | if (size > buffer_size) |
756 | return -ERANGE; | |
757 | buf += size; | |
758 | buffer_size -= size; | |
759 | } | |
760 | size = buf - buffer; | |
761 | } | |
762 | return size; | |
763 | } | |
764 | ||
765 | /* | |
766 | * Find the handler for the prefix and dispatch its set() operation. | |
767 | */ | |
768 | int | |
769 | generic_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags) | |
770 | { | |
bb435453 | 771 | const struct xattr_handler *handler; |
1da177e4 LT |
772 | |
773 | if (size == 0) | |
774 | value = ""; /* empty EA, do not remove */ | |
431547b3 | 775 | handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name); |
1da177e4 LT |
776 | if (!handler) |
777 | return -EOPNOTSUPP; | |
df7e1303 | 778 | return handler->set(dentry, name, value, size, flags, handler->flags); |
1da177e4 LT |
779 | } |
780 | ||
781 | /* | |
782 | * Find the handler for the prefix and dispatch its set() operation to remove | |
783 | * any associated extended attribute. | |
784 | */ | |
785 | int | |
786 | generic_removexattr(struct dentry *dentry, const char *name) | |
787 | { | |
bb435453 | 788 | const struct xattr_handler *handler; |
1da177e4 | 789 | |
431547b3 | 790 | handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name); |
1da177e4 LT |
791 | if (!handler) |
792 | return -EOPNOTSUPP; | |
431547b3 CH |
793 | return handler->set(dentry, name, NULL, 0, |
794 | XATTR_REPLACE, handler->flags); | |
1da177e4 LT |
795 | } |
796 | ||
797 | EXPORT_SYMBOL(generic_getxattr); | |
798 | EXPORT_SYMBOL(generic_listxattr); | |
799 | EXPORT_SYMBOL(generic_setxattr); | |
800 | EXPORT_SYMBOL(generic_removexattr); |