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 | ||
2ab51f37 | 299 | mutex_lock(&inode->i_mutex); |
5be196e5 | 300 | error = security_inode_removexattr(dentry, name); |
2ab51f37 MZ |
301 | if (error) { |
302 | mutex_unlock(&inode->i_mutex); | |
5be196e5 | 303 | return error; |
2ab51f37 | 304 | } |
5be196e5 | 305 | |
5be196e5 CH |
306 | error = inode->i_op->removexattr(dentry, name); |
307 | mutex_unlock(&inode->i_mutex); | |
308 | ||
c7b87de2 | 309 | if (!error) { |
5be196e5 | 310 | fsnotify_xattr(dentry); |
c7b87de2 MZ |
311 | evm_inode_post_removexattr(dentry, name); |
312 | } | |
5be196e5 CH |
313 | return error; |
314 | } | |
315 | EXPORT_SYMBOL_GPL(vfs_removexattr); | |
316 | ||
317 | ||
1da177e4 LT |
318 | /* |
319 | * Extended attribute SET operations | |
320 | */ | |
321 | static long | |
8f0cfa52 | 322 | setxattr(struct dentry *d, const char __user *name, const void __user *value, |
1da177e4 LT |
323 | size_t size, int flags) |
324 | { | |
325 | int error; | |
326 | void *kvalue = NULL; | |
44c82498 | 327 | void *vvalue = NULL; /* If non-NULL, we used vmalloc() */ |
1da177e4 LT |
328 | char kname[XATTR_NAME_MAX + 1]; |
329 | ||
330 | if (flags & ~(XATTR_CREATE|XATTR_REPLACE)) | |
331 | return -EINVAL; | |
332 | ||
333 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
334 | if (error == 0 || error == sizeof(kname)) | |
335 | error = -ERANGE; | |
336 | if (error < 0) | |
337 | return error; | |
338 | ||
339 | if (size) { | |
340 | if (size > XATTR_SIZE_MAX) | |
341 | return -E2BIG; | |
44c82498 AM |
342 | kvalue = kmalloc(size, GFP_KERNEL | __GFP_NOWARN); |
343 | if (!kvalue) { | |
344 | vvalue = vmalloc(size); | |
345 | if (!vvalue) | |
346 | return -ENOMEM; | |
347 | kvalue = vvalue; | |
348 | } | |
349 | if (copy_from_user(kvalue, value, size)) { | |
350 | error = -EFAULT; | |
351 | goto out; | |
352 | } | |
2f6f0654 EB |
353 | if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) || |
354 | (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)) | |
355 | posix_acl_fix_xattr_from_user(kvalue, size); | |
1da177e4 LT |
356 | } |
357 | ||
5be196e5 | 358 | error = vfs_setxattr(d, kname, kvalue, size, flags); |
44c82498 AM |
359 | out: |
360 | if (vvalue) | |
361 | vfree(vvalue); | |
362 | else | |
363 | kfree(kvalue); | |
1da177e4 LT |
364 | return error; |
365 | } | |
366 | ||
64fd1de3 HC |
367 | SYSCALL_DEFINE5(setxattr, const char __user *, pathname, |
368 | const char __user *, name, const void __user *, value, | |
369 | size_t, size, int, flags) | |
1da177e4 | 370 | { |
2d8f3038 | 371 | struct path path; |
1da177e4 | 372 | int error; |
68f1bb8b JL |
373 | unsigned int lookup_flags = LOOKUP_FOLLOW; |
374 | retry: | |
375 | error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); | |
1da177e4 LT |
376 | if (error) |
377 | return error; | |
2d8f3038 | 378 | error = mnt_want_write(path.mnt); |
18f335af | 379 | if (!error) { |
2d8f3038 AV |
380 | error = setxattr(path.dentry, name, value, size, flags); |
381 | mnt_drop_write(path.mnt); | |
18f335af | 382 | } |
2d8f3038 | 383 | path_put(&path); |
68f1bb8b JL |
384 | if (retry_estale(error, lookup_flags)) { |
385 | lookup_flags |= LOOKUP_REVAL; | |
386 | goto retry; | |
387 | } | |
1da177e4 LT |
388 | return error; |
389 | } | |
390 | ||
64fd1de3 HC |
391 | SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname, |
392 | const char __user *, name, const void __user *, value, | |
393 | size_t, size, int, flags) | |
1da177e4 | 394 | { |
2d8f3038 | 395 | struct path path; |
1da177e4 LT |
396 | int error; |
397 | ||
2d8f3038 | 398 | error = user_lpath(pathname, &path); |
1da177e4 LT |
399 | if (error) |
400 | return error; | |
2d8f3038 | 401 | error = mnt_want_write(path.mnt); |
18f335af | 402 | if (!error) { |
2d8f3038 AV |
403 | error = setxattr(path.dentry, name, value, size, flags); |
404 | mnt_drop_write(path.mnt); | |
18f335af | 405 | } |
2d8f3038 | 406 | path_put(&path); |
1da177e4 LT |
407 | return error; |
408 | } | |
409 | ||
64fd1de3 HC |
410 | SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name, |
411 | const void __user *,value, size_t, size, int, flags) | |
1da177e4 | 412 | { |
2903ff01 | 413 | struct fd f = fdget(fd); |
73241ccc | 414 | struct dentry *dentry; |
1da177e4 LT |
415 | int error = -EBADF; |
416 | ||
2903ff01 | 417 | if (!f.file) |
1da177e4 | 418 | return error; |
2903ff01 | 419 | dentry = f.file->f_path.dentry; |
bfcec708 | 420 | audit_inode(NULL, dentry, 0); |
2903ff01 | 421 | error = mnt_want_write_file(f.file); |
18f335af DH |
422 | if (!error) { |
423 | error = setxattr(dentry, name, value, size, flags); | |
2903ff01 | 424 | mnt_drop_write_file(f.file); |
18f335af | 425 | } |
2903ff01 | 426 | fdput(f); |
1da177e4 LT |
427 | return error; |
428 | } | |
429 | ||
430 | /* | |
431 | * Extended attribute GET operations | |
432 | */ | |
433 | static ssize_t | |
8f0cfa52 DH |
434 | getxattr(struct dentry *d, const char __user *name, void __user *value, |
435 | size_t size) | |
1da177e4 LT |
436 | { |
437 | ssize_t error; | |
438 | void *kvalue = NULL; | |
779302e6 | 439 | void *vvalue = NULL; |
1da177e4 LT |
440 | char kname[XATTR_NAME_MAX + 1]; |
441 | ||
442 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
443 | if (error == 0 || error == sizeof(kname)) | |
444 | error = -ERANGE; | |
445 | if (error < 0) | |
446 | return error; | |
447 | ||
448 | if (size) { | |
449 | if (size > XATTR_SIZE_MAX) | |
450 | size = XATTR_SIZE_MAX; | |
779302e6 SL |
451 | kvalue = kzalloc(size, GFP_KERNEL | __GFP_NOWARN); |
452 | if (!kvalue) { | |
453 | vvalue = vmalloc(size); | |
454 | if (!vvalue) | |
455 | return -ENOMEM; | |
456 | kvalue = vvalue; | |
457 | } | |
1da177e4 LT |
458 | } |
459 | ||
5be196e5 | 460 | error = vfs_getxattr(d, kname, kvalue, size); |
f549d6c1 | 461 | if (error > 0) { |
2f6f0654 EB |
462 | if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) || |
463 | (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)) | |
464 | posix_acl_fix_xattr_to_user(kvalue, size); | |
f549d6c1 SS |
465 | if (size && copy_to_user(value, kvalue, error)) |
466 | error = -EFAULT; | |
467 | } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) { | |
468 | /* The file system tried to returned a value bigger | |
469 | than XATTR_SIZE_MAX bytes. Not possible. */ | |
470 | error = -E2BIG; | |
1da177e4 | 471 | } |
779302e6 SL |
472 | if (vvalue) |
473 | vfree(vvalue); | |
474 | else | |
475 | kfree(kvalue); | |
1da177e4 LT |
476 | return error; |
477 | } | |
478 | ||
64fd1de3 HC |
479 | SYSCALL_DEFINE4(getxattr, const char __user *, pathname, |
480 | const char __user *, name, void __user *, value, size_t, size) | |
1da177e4 | 481 | { |
2d8f3038 | 482 | struct path path; |
1da177e4 LT |
483 | ssize_t error; |
484 | ||
2d8f3038 | 485 | error = user_path(pathname, &path); |
1da177e4 LT |
486 | if (error) |
487 | return error; | |
2d8f3038 AV |
488 | error = getxattr(path.dentry, name, value, size); |
489 | path_put(&path); | |
1da177e4 LT |
490 | return error; |
491 | } | |
492 | ||
64fd1de3 HC |
493 | SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname, |
494 | const char __user *, name, void __user *, value, size_t, size) | |
1da177e4 | 495 | { |
2d8f3038 | 496 | struct path path; |
1da177e4 LT |
497 | ssize_t error; |
498 | ||
2d8f3038 | 499 | error = user_lpath(pathname, &path); |
1da177e4 LT |
500 | if (error) |
501 | return error; | |
2d8f3038 AV |
502 | error = getxattr(path.dentry, name, value, size); |
503 | path_put(&path); | |
1da177e4 LT |
504 | return error; |
505 | } | |
506 | ||
64fd1de3 HC |
507 | SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name, |
508 | void __user *, value, size_t, size) | |
1da177e4 | 509 | { |
2903ff01 | 510 | struct fd f = fdget(fd); |
1da177e4 LT |
511 | ssize_t error = -EBADF; |
512 | ||
2903ff01 | 513 | if (!f.file) |
1da177e4 | 514 | return error; |
bfcec708 | 515 | audit_inode(NULL, f.file->f_path.dentry, 0); |
2903ff01 AV |
516 | error = getxattr(f.file->f_path.dentry, name, value, size); |
517 | fdput(f); | |
1da177e4 LT |
518 | return error; |
519 | } | |
520 | ||
521 | /* | |
522 | * Extended attribute LIST operations | |
523 | */ | |
524 | static ssize_t | |
525 | listxattr(struct dentry *d, char __user *list, size_t size) | |
526 | { | |
527 | ssize_t error; | |
528 | char *klist = NULL; | |
0d08d7b7 | 529 | char *vlist = NULL; /* If non-NULL, we used vmalloc() */ |
1da177e4 LT |
530 | |
531 | if (size) { | |
532 | if (size > XATTR_LIST_MAX) | |
533 | size = XATTR_LIST_MAX; | |
703bf2d1 | 534 | klist = kmalloc(size, __GFP_NOWARN | GFP_KERNEL); |
0d08d7b7 AM |
535 | if (!klist) { |
536 | vlist = vmalloc(size); | |
537 | if (!vlist) | |
538 | return -ENOMEM; | |
539 | klist = vlist; | |
540 | } | |
1da177e4 LT |
541 | } |
542 | ||
659564c8 | 543 | error = vfs_listxattr(d, klist, size); |
f549d6c1 SS |
544 | if (error > 0) { |
545 | if (size && copy_to_user(list, klist, error)) | |
546 | error = -EFAULT; | |
547 | } else if (error == -ERANGE && size >= XATTR_LIST_MAX) { | |
548 | /* The file system tried to returned a list bigger | |
549 | than XATTR_LIST_MAX bytes. Not possible. */ | |
550 | error = -E2BIG; | |
1da177e4 | 551 | } |
0d08d7b7 AM |
552 | if (vlist) |
553 | vfree(vlist); | |
554 | else | |
555 | kfree(klist); | |
1da177e4 LT |
556 | return error; |
557 | } | |
558 | ||
64fd1de3 HC |
559 | SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list, |
560 | size_t, size) | |
1da177e4 | 561 | { |
2d8f3038 | 562 | struct path path; |
1da177e4 LT |
563 | ssize_t error; |
564 | ||
2d8f3038 | 565 | error = user_path(pathname, &path); |
1da177e4 LT |
566 | if (error) |
567 | return error; | |
2d8f3038 AV |
568 | error = listxattr(path.dentry, list, size); |
569 | path_put(&path); | |
1da177e4 LT |
570 | return error; |
571 | } | |
572 | ||
64fd1de3 HC |
573 | SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list, |
574 | size_t, size) | |
1da177e4 | 575 | { |
2d8f3038 | 576 | struct path path; |
1da177e4 LT |
577 | ssize_t error; |
578 | ||
2d8f3038 | 579 | error = user_lpath(pathname, &path); |
1da177e4 LT |
580 | if (error) |
581 | return error; | |
2d8f3038 AV |
582 | error = listxattr(path.dentry, list, size); |
583 | path_put(&path); | |
1da177e4 LT |
584 | return error; |
585 | } | |
586 | ||
64fd1de3 | 587 | SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size) |
1da177e4 | 588 | { |
2903ff01 | 589 | struct fd f = fdget(fd); |
1da177e4 LT |
590 | ssize_t error = -EBADF; |
591 | ||
2903ff01 | 592 | if (!f.file) |
1da177e4 | 593 | return error; |
bfcec708 | 594 | audit_inode(NULL, f.file->f_path.dentry, 0); |
2903ff01 AV |
595 | error = listxattr(f.file->f_path.dentry, list, size); |
596 | fdput(f); | |
1da177e4 LT |
597 | return error; |
598 | } | |
599 | ||
600 | /* | |
601 | * Extended attribute REMOVE operations | |
602 | */ | |
603 | static long | |
8f0cfa52 | 604 | removexattr(struct dentry *d, const char __user *name) |
1da177e4 LT |
605 | { |
606 | int error; | |
607 | char kname[XATTR_NAME_MAX + 1]; | |
608 | ||
609 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
610 | if (error == 0 || error == sizeof(kname)) | |
611 | error = -ERANGE; | |
612 | if (error < 0) | |
613 | return error; | |
614 | ||
5be196e5 | 615 | return vfs_removexattr(d, kname); |
1da177e4 LT |
616 | } |
617 | ||
64fd1de3 HC |
618 | SYSCALL_DEFINE2(removexattr, const char __user *, pathname, |
619 | const char __user *, name) | |
1da177e4 | 620 | { |
2d8f3038 | 621 | struct path path; |
1da177e4 LT |
622 | int error; |
623 | ||
2d8f3038 | 624 | error = user_path(pathname, &path); |
1da177e4 LT |
625 | if (error) |
626 | return error; | |
2d8f3038 | 627 | error = mnt_want_write(path.mnt); |
18f335af | 628 | if (!error) { |
2d8f3038 AV |
629 | error = removexattr(path.dentry, name); |
630 | mnt_drop_write(path.mnt); | |
18f335af | 631 | } |
2d8f3038 | 632 | path_put(&path); |
1da177e4 LT |
633 | return error; |
634 | } | |
635 | ||
6a6160a7 HC |
636 | SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname, |
637 | const char __user *, name) | |
1da177e4 | 638 | { |
2d8f3038 | 639 | struct path path; |
1da177e4 LT |
640 | int error; |
641 | ||
2d8f3038 | 642 | error = user_lpath(pathname, &path); |
1da177e4 LT |
643 | if (error) |
644 | return error; | |
2d8f3038 | 645 | error = mnt_want_write(path.mnt); |
18f335af | 646 | if (!error) { |
2d8f3038 AV |
647 | error = removexattr(path.dentry, name); |
648 | mnt_drop_write(path.mnt); | |
18f335af | 649 | } |
2d8f3038 | 650 | path_put(&path); |
1da177e4 LT |
651 | return error; |
652 | } | |
653 | ||
6a6160a7 | 654 | SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name) |
1da177e4 | 655 | { |
2903ff01 | 656 | struct fd f = fdget(fd); |
73241ccc | 657 | struct dentry *dentry; |
1da177e4 LT |
658 | int error = -EBADF; |
659 | ||
2903ff01 | 660 | if (!f.file) |
1da177e4 | 661 | return error; |
2903ff01 | 662 | dentry = f.file->f_path.dentry; |
bfcec708 | 663 | audit_inode(NULL, dentry, 0); |
2903ff01 | 664 | error = mnt_want_write_file(f.file); |
18f335af DH |
665 | if (!error) { |
666 | error = removexattr(dentry, name); | |
2903ff01 | 667 | mnt_drop_write_file(f.file); |
18f335af | 668 | } |
2903ff01 | 669 | fdput(f); |
1da177e4 LT |
670 | return error; |
671 | } | |
672 | ||
673 | ||
674 | static const char * | |
675 | strcmp_prefix(const char *a, const char *a_prefix) | |
676 | { | |
677 | while (*a_prefix && *a == *a_prefix) { | |
678 | a++; | |
679 | a_prefix++; | |
680 | } | |
681 | return *a_prefix ? NULL : a; | |
682 | } | |
683 | ||
684 | /* | |
685 | * In order to implement different sets of xattr operations for each xattr | |
686 | * prefix with the generic xattr API, a filesystem should create a | |
687 | * null-terminated array of struct xattr_handler (one for each prefix) and | |
688 | * hang a pointer to it off of the s_xattr field of the superblock. | |
689 | * | |
690 | * The generic_fooxattr() functions will use this list to dispatch xattr | |
691 | * operations to the correct xattr_handler. | |
692 | */ | |
693 | #define for_each_xattr_handler(handlers, handler) \ | |
694 | for ((handler) = *(handlers)++; \ | |
695 | (handler) != NULL; \ | |
696 | (handler) = *(handlers)++) | |
697 | ||
698 | /* | |
699 | * Find the xattr_handler with the matching prefix. | |
700 | */ | |
bb435453 SH |
701 | static const struct xattr_handler * |
702 | xattr_resolve_name(const struct xattr_handler **handlers, const char **name) | |
1da177e4 | 703 | { |
bb435453 | 704 | const struct xattr_handler *handler; |
1da177e4 LT |
705 | |
706 | if (!*name) | |
707 | return NULL; | |
708 | ||
709 | for_each_xattr_handler(handlers, handler) { | |
710 | const char *n = strcmp_prefix(*name, handler->prefix); | |
711 | if (n) { | |
712 | *name = n; | |
713 | break; | |
714 | } | |
715 | } | |
716 | return handler; | |
717 | } | |
718 | ||
719 | /* | |
720 | * Find the handler for the prefix and dispatch its get() operation. | |
721 | */ | |
722 | ssize_t | |
723 | generic_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size) | |
724 | { | |
bb435453 | 725 | const struct xattr_handler *handler; |
1da177e4 | 726 | |
431547b3 | 727 | handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name); |
1da177e4 LT |
728 | if (!handler) |
729 | return -EOPNOTSUPP; | |
431547b3 | 730 | return handler->get(dentry, name, buffer, size, handler->flags); |
1da177e4 LT |
731 | } |
732 | ||
733 | /* | |
734 | * Combine the results of the list() operation from every xattr_handler in the | |
735 | * list. | |
736 | */ | |
737 | ssize_t | |
738 | generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) | |
739 | { | |
bb435453 | 740 | const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr; |
1da177e4 LT |
741 | unsigned int size = 0; |
742 | ||
743 | if (!buffer) { | |
431547b3 CH |
744 | for_each_xattr_handler(handlers, handler) { |
745 | size += handler->list(dentry, NULL, 0, NULL, 0, | |
746 | handler->flags); | |
747 | } | |
1da177e4 LT |
748 | } else { |
749 | char *buf = buffer; | |
750 | ||
751 | for_each_xattr_handler(handlers, handler) { | |
431547b3 CH |
752 | size = handler->list(dentry, buf, buffer_size, |
753 | NULL, 0, handler->flags); | |
1da177e4 LT |
754 | if (size > buffer_size) |
755 | return -ERANGE; | |
756 | buf += size; | |
757 | buffer_size -= size; | |
758 | } | |
759 | size = buf - buffer; | |
760 | } | |
761 | return size; | |
762 | } | |
763 | ||
764 | /* | |
765 | * Find the handler for the prefix and dispatch its set() operation. | |
766 | */ | |
767 | int | |
768 | generic_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags) | |
769 | { | |
bb435453 | 770 | const struct xattr_handler *handler; |
1da177e4 LT |
771 | |
772 | if (size == 0) | |
773 | value = ""; /* empty EA, do not remove */ | |
431547b3 | 774 | handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name); |
1da177e4 LT |
775 | if (!handler) |
776 | return -EOPNOTSUPP; | |
df7e1303 | 777 | return handler->set(dentry, name, value, size, flags, handler->flags); |
1da177e4 LT |
778 | } |
779 | ||
780 | /* | |
781 | * Find the handler for the prefix and dispatch its set() operation to remove | |
782 | * any associated extended attribute. | |
783 | */ | |
784 | int | |
785 | generic_removexattr(struct dentry *dentry, const char *name) | |
786 | { | |
bb435453 | 787 | const struct xattr_handler *handler; |
1da177e4 | 788 | |
431547b3 | 789 | handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name); |
1da177e4 LT |
790 | if (!handler) |
791 | return -EOPNOTSUPP; | |
431547b3 CH |
792 | return handler->set(dentry, name, NULL, 0, |
793 | XATTR_REPLACE, handler->flags); | |
1da177e4 LT |
794 | } |
795 | ||
796 | EXPORT_SYMBOL(generic_getxattr); | |
797 | EXPORT_SYMBOL(generic_listxattr); | |
798 | EXPORT_SYMBOL(generic_setxattr); | |
799 | EXPORT_SYMBOL(generic_removexattr); | |
38f38657 AR |
800 | |
801 | /* | |
802 | * Allocate new xattr and copy in the value; but leave the name to callers. | |
803 | */ | |
804 | struct simple_xattr *simple_xattr_alloc(const void *value, size_t size) | |
805 | { | |
806 | struct simple_xattr *new_xattr; | |
807 | size_t len; | |
808 | ||
809 | /* wrap around? */ | |
810 | len = sizeof(*new_xattr) + size; | |
811 | if (len <= sizeof(*new_xattr)) | |
812 | return NULL; | |
813 | ||
814 | new_xattr = kmalloc(len, GFP_KERNEL); | |
815 | if (!new_xattr) | |
816 | return NULL; | |
817 | ||
818 | new_xattr->size = size; | |
819 | memcpy(new_xattr->value, value, size); | |
820 | return new_xattr; | |
821 | } | |
822 | ||
823 | /* | |
824 | * xattr GET operation for in-memory/pseudo filesystems | |
825 | */ | |
826 | int simple_xattr_get(struct simple_xattrs *xattrs, const char *name, | |
827 | void *buffer, size_t size) | |
828 | { | |
829 | struct simple_xattr *xattr; | |
830 | int ret = -ENODATA; | |
831 | ||
832 | spin_lock(&xattrs->lock); | |
833 | list_for_each_entry(xattr, &xattrs->head, list) { | |
834 | if (strcmp(name, xattr->name)) | |
835 | continue; | |
836 | ||
837 | ret = xattr->size; | |
838 | if (buffer) { | |
839 | if (size < xattr->size) | |
840 | ret = -ERANGE; | |
841 | else | |
842 | memcpy(buffer, xattr->value, xattr->size); | |
843 | } | |
844 | break; | |
845 | } | |
846 | spin_unlock(&xattrs->lock); | |
847 | return ret; | |
848 | } | |
849 | ||
850 | static int __simple_xattr_set(struct simple_xattrs *xattrs, const char *name, | |
851 | const void *value, size_t size, int flags) | |
852 | { | |
853 | struct simple_xattr *xattr; | |
43385846 | 854 | struct simple_xattr *new_xattr = NULL; |
38f38657 AR |
855 | int err = 0; |
856 | ||
857 | /* value == NULL means remove */ | |
858 | if (value) { | |
859 | new_xattr = simple_xattr_alloc(value, size); | |
860 | if (!new_xattr) | |
861 | return -ENOMEM; | |
862 | ||
863 | new_xattr->name = kstrdup(name, GFP_KERNEL); | |
864 | if (!new_xattr->name) { | |
865 | kfree(new_xattr); | |
866 | return -ENOMEM; | |
867 | } | |
868 | } | |
869 | ||
870 | spin_lock(&xattrs->lock); | |
871 | list_for_each_entry(xattr, &xattrs->head, list) { | |
872 | if (!strcmp(name, xattr->name)) { | |
873 | if (flags & XATTR_CREATE) { | |
874 | xattr = new_xattr; | |
875 | err = -EEXIST; | |
876 | } else if (new_xattr) { | |
877 | list_replace(&xattr->list, &new_xattr->list); | |
878 | } else { | |
879 | list_del(&xattr->list); | |
880 | } | |
881 | goto out; | |
882 | } | |
883 | } | |
884 | if (flags & XATTR_REPLACE) { | |
885 | xattr = new_xattr; | |
886 | err = -ENODATA; | |
887 | } else { | |
888 | list_add(&new_xattr->list, &xattrs->head); | |
889 | xattr = NULL; | |
890 | } | |
891 | out: | |
892 | spin_unlock(&xattrs->lock); | |
893 | if (xattr) { | |
894 | kfree(xattr->name); | |
895 | kfree(xattr); | |
896 | } | |
897 | return err; | |
898 | ||
899 | } | |
900 | ||
4895768b AR |
901 | /** |
902 | * simple_xattr_set - xattr SET operation for in-memory/pseudo filesystems | |
903 | * @xattrs: target simple_xattr list | |
904 | * @name: name of the new extended attribute | |
905 | * @value: value of the new xattr. If %NULL, will remove the attribute | |
906 | * @size: size of the new xattr | |
907 | * @flags: %XATTR_{CREATE|REPLACE} | |
908 | * | |
909 | * %XATTR_CREATE is set, the xattr shouldn't exist already; otherwise fails | |
910 | * with -EEXIST. If %XATTR_REPLACE is set, the xattr should exist; | |
911 | * otherwise, fails with -ENODATA. | |
912 | * | |
913 | * Returns 0 on success, -errno on failure. | |
38f38657 AR |
914 | */ |
915 | int simple_xattr_set(struct simple_xattrs *xattrs, const char *name, | |
916 | const void *value, size_t size, int flags) | |
917 | { | |
918 | if (size == 0) | |
919 | value = ""; /* empty EA, do not remove */ | |
920 | return __simple_xattr_set(xattrs, name, value, size, flags); | |
921 | } | |
922 | ||
923 | /* | |
924 | * xattr REMOVE operation for in-memory/pseudo filesystems | |
925 | */ | |
926 | int simple_xattr_remove(struct simple_xattrs *xattrs, const char *name) | |
927 | { | |
928 | return __simple_xattr_set(xattrs, name, NULL, 0, XATTR_REPLACE); | |
929 | } | |
930 | ||
931 | static bool xattr_is_trusted(const char *name) | |
932 | { | |
933 | return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN); | |
934 | } | |
935 | ||
936 | /* | |
937 | * xattr LIST operation for in-memory/pseudo filesystems | |
938 | */ | |
939 | ssize_t simple_xattr_list(struct simple_xattrs *xattrs, char *buffer, | |
940 | size_t size) | |
941 | { | |
942 | bool trusted = capable(CAP_SYS_ADMIN); | |
943 | struct simple_xattr *xattr; | |
944 | size_t used = 0; | |
945 | ||
946 | spin_lock(&xattrs->lock); | |
947 | list_for_each_entry(xattr, &xattrs->head, list) { | |
948 | size_t len; | |
949 | ||
950 | /* skip "trusted." attributes for unprivileged callers */ | |
951 | if (!trusted && xattr_is_trusted(xattr->name)) | |
952 | continue; | |
953 | ||
954 | len = strlen(xattr->name) + 1; | |
955 | used += len; | |
956 | if (buffer) { | |
957 | if (size < used) { | |
958 | used = -ERANGE; | |
959 | break; | |
960 | } | |
961 | memcpy(buffer, xattr->name, len); | |
962 | buffer += len; | |
963 | } | |
964 | } | |
965 | spin_unlock(&xattrs->lock); | |
966 | ||
967 | return used; | |
968 | } | |
969 | ||
4895768b AR |
970 | /* |
971 | * Adds an extended attribute to the list | |
972 | */ | |
38f38657 AR |
973 | void simple_xattr_list_add(struct simple_xattrs *xattrs, |
974 | struct simple_xattr *new_xattr) | |
975 | { | |
976 | spin_lock(&xattrs->lock); | |
977 | list_add(&new_xattr->list, &xattrs->head); | |
978 | spin_unlock(&xattrs->lock); | |
979 | } |