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Commit | Line | Data |
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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> |
1da177e4 | 23 | |
0d08d7b7 | 24 | #include <asm/uaccess.h> |
5be196e5 | 25 | |
e0ad7b07 | 26 | /* |
27 | * Check permissions for extended attribute access. This is a bit complicated | |
28 | * because different namespaces have very different rules. | |
29 | */ | |
30 | static int | |
31 | xattr_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) { | |
e0ad7b07 | 38 | 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 | /* | |
55b23bde | 51 | * The trusted.* namespace can only be accessed by privileged users. |
e0ad7b07 | 52 | */ |
55b23bde AG |
53 | 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 | } | |
e0ad7b07 | 58 | |
55b23bde AG |
59 | /* |
60 | * In the user.* namespace, only regular files and directories can have | |
f1f2d871 | 61 | * extended attributes. For sticky directories, only the owner and |
55b23bde | 62 | * privileged users can write attributes. |
f1f2d871 | 63 | */ |
e0ad7b07 | 64 | if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) { |
f1f2d871 | 65 | if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode)) |
55b23bde | 66 | return (mask & MAY_WRITE) ? -EPERM : -ENODATA; |
f1f2d871 | 67 | if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) && |
2e149670 | 68 | (mask & MAY_WRITE) && !inode_owner_or_capable(inode)) |
e0ad7b07 | 69 | return -EPERM; |
70 | } | |
71 | ||
f419a2e3 | 72 | return inode_permission(inode, mask); |
e0ad7b07 | 73 | } |
74 | ||
b1ab7e4b DQ |
75 | /** |
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 | */ | |
91 | int __vfs_setxattr_noperm(struct dentry *dentry, const char *name, | |
92 | const void *value, size_t size, int flags) | |
5be196e5 CH |
93 | { |
94 | struct inode *inode = dentry->d_inode; | |
b1ab7e4b | 95 | int error = -EOPNOTSUPP; |
69b45732 AK |
96 | int issec = !strncmp(name, XATTR_SECURITY_PREFIX, |
97 | XATTR_SECURITY_PREFIX_LEN); | |
e0ad7b07 | 98 | |
69b45732 AK |
99 | if (issec) |
100 | inode->i_flags &= ~S_NOSEC; | |
5be196e5 CH |
101 | 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 | } | |
69b45732 | 108 | } else if (issec) { |
e0ad7b07 | 109 | const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; |
5be196e5 CH |
110 | error = security_inode_setsecurity(inode, suffix, value, |
111 | size, flags); | |
112 | if (!error) | |
113 | fsnotify_xattr(dentry); | |
114 | } | |
b1ab7e4b DQ |
115 | |
116 | return error; | |
117 | } | |
118 | ||
119 | ||
120 | int | |
121 | vfs_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 | ||
5be196e5 CH |
138 | out: |
139 | mutex_unlock(&inode->i_mutex); | |
140 | return error; | |
141 | } | |
142 | EXPORT_SYMBOL_GPL(vfs_setxattr); | |
143 | ||
42492594 DQ |
144 | ssize_t |
145 | xattr_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); | |
164 | out: | |
165 | security_release_secctx(buffer, len); | |
166 | out_noalloc: | |
167 | return len; | |
168 | } | |
169 | EXPORT_SYMBOL_GPL(xattr_getsecurity); | |
170 | ||
1601fbad MZ |
171 | /* |
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 | */ | |
179 | ssize_t | |
180 | vfs_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 */ | |
211 | int 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 | ||
5be196e5 | 229 | ssize_t |
8f0cfa52 | 230 | vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size) |
5be196e5 CH |
231 | { |
232 | struct inode *inode = dentry->d_inode; | |
233 | int error; | |
234 | ||
e0ad7b07 | 235 | error = xattr_permission(inode, name, MAY_READ); |
236 | if (error) | |
237 | return error; | |
238 | ||
5be196e5 CH |
239 | error = security_inode_getxattr(dentry, name); |
240 | if (error) | |
241 | return error; | |
242 | ||
5be196e5 | 243 | if (!strncmp(name, XATTR_SECURITY_PREFIX, |
e0ad7b07 | 244 | XATTR_SECURITY_PREFIX_LEN)) { |
245 | const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; | |
42492594 | 246 | int ret = xattr_getsecurity(inode, suffix, value, size); |
5be196e5 CH |
247 | /* |
248 | * Only overwrite the return value if a security module | |
249 | * is actually active. | |
250 | */ | |
4bea5805 DQ |
251 | if (ret == -EOPNOTSUPP) |
252 | goto nolsm; | |
253 | return ret; | |
5be196e5 | 254 | } |
4bea5805 DQ |
255 | nolsm: |
256 | if (inode->i_op->getxattr) | |
257 | error = inode->i_op->getxattr(dentry, name, value, size); | |
258 | else | |
259 | error = -EOPNOTSUPP; | |
5be196e5 CH |
260 | |
261 | return error; | |
262 | } | |
263 | EXPORT_SYMBOL_GPL(vfs_getxattr); | |
264 | ||
659564c8 BN |
265 | ssize_t |
266 | vfs_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; | |
acfa4380 | 274 | if (d->d_inode->i_op->listxattr) { |
659564c8 BN |
275 | 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 | } | |
283 | EXPORT_SYMBOL_GPL(vfs_listxattr); | |
284 | ||
5be196e5 | 285 | int |
8f0cfa52 | 286 | vfs_removexattr(struct dentry *dentry, const char *name) |
5be196e5 CH |
287 | { |
288 | struct inode *inode = dentry->d_inode; | |
289 | int error; | |
290 | ||
291 | if (!inode->i_op->removexattr) | |
292 | return -EOPNOTSUPP; | |
293 | ||
e0ad7b07 | 294 | error = xattr_permission(inode, name, MAY_WRITE); |
295 | if (error) | |
296 | return error; | |
297 | ||
5be196e5 CH |
298 | 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 | ||
c7b87de2 | 306 | if (!error) { |
5be196e5 | 307 | fsnotify_xattr(dentry); |
c7b87de2 MZ |
308 | evm_inode_post_removexattr(dentry, name); |
309 | } | |
5be196e5 CH |
310 | return error; |
311 | } | |
312 | EXPORT_SYMBOL_GPL(vfs_removexattr); | |
313 | ||
314 | ||
1da177e4 LT |
315 | /* |
316 | * Extended attribute SET operations | |
317 | */ | |
318 | static long | |
8f0cfa52 | 319 | setxattr(struct dentry *d, const char __user *name, const void __user *value, |
1da177e4 LT |
320 | size_t size, int flags) |
321 | { | |
322 | int error; | |
323 | void *kvalue = NULL; | |
324 | char kname[XATTR_NAME_MAX + 1]; | |
325 | ||
326 | if (flags & ~(XATTR_CREATE|XATTR_REPLACE)) | |
327 | return -EINVAL; | |
328 | ||
329 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
330 | if (error == 0 || error == sizeof(kname)) | |
331 | error = -ERANGE; | |
332 | if (error < 0) | |
333 | return error; | |
334 | ||
335 | if (size) { | |
336 | if (size > XATTR_SIZE_MAX) | |
337 | return -E2BIG; | |
3939fcde LZ |
338 | kvalue = memdup_user(value, size); |
339 | if (IS_ERR(kvalue)) | |
340 | return PTR_ERR(kvalue); | |
1da177e4 LT |
341 | } |
342 | ||
5be196e5 | 343 | error = vfs_setxattr(d, kname, kvalue, size, flags); |
f99d49ad | 344 | kfree(kvalue); |
1da177e4 LT |
345 | return error; |
346 | } | |
347 | ||
64fd1de3 HC |
348 | SYSCALL_DEFINE5(setxattr, const char __user *, pathname, |
349 | const char __user *, name, const void __user *, value, | |
350 | size_t, size, int, flags) | |
1da177e4 | 351 | { |
2d8f3038 | 352 | struct path path; |
1da177e4 LT |
353 | int error; |
354 | ||
2d8f3038 | 355 | error = user_path(pathname, &path); |
1da177e4 LT |
356 | if (error) |
357 | return error; | |
2d8f3038 | 358 | error = mnt_want_write(path.mnt); |
18f335af | 359 | if (!error) { |
2d8f3038 AV |
360 | error = setxattr(path.dentry, name, value, size, flags); |
361 | mnt_drop_write(path.mnt); | |
18f335af | 362 | } |
2d8f3038 | 363 | path_put(&path); |
1da177e4 LT |
364 | return error; |
365 | } | |
366 | ||
64fd1de3 HC |
367 | SYSCALL_DEFINE5(lsetxattr, 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 LT |
372 | int error; |
373 | ||
2d8f3038 | 374 | error = user_lpath(pathname, &path); |
1da177e4 LT |
375 | if (error) |
376 | return error; | |
2d8f3038 | 377 | error = mnt_want_write(path.mnt); |
18f335af | 378 | if (!error) { |
2d8f3038 AV |
379 | error = setxattr(path.dentry, name, value, size, flags); |
380 | mnt_drop_write(path.mnt); | |
18f335af | 381 | } |
2d8f3038 | 382 | path_put(&path); |
1da177e4 LT |
383 | return error; |
384 | } | |
385 | ||
64fd1de3 HC |
386 | SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name, |
387 | const void __user *,value, size_t, size, int, flags) | |
1da177e4 LT |
388 | { |
389 | struct file *f; | |
73241ccc | 390 | struct dentry *dentry; |
1da177e4 LT |
391 | int error = -EBADF; |
392 | ||
393 | f = fget(fd); | |
394 | if (!f) | |
395 | return error; | |
0f7fc9e4 | 396 | dentry = f->f_path.dentry; |
5a190ae6 | 397 | audit_inode(NULL, dentry); |
96029c4e | 398 | error = mnt_want_write_file(f); |
18f335af DH |
399 | if (!error) { |
400 | error = setxattr(dentry, name, value, size, flags); | |
2a79f17e | 401 | mnt_drop_write_file(f); |
18f335af | 402 | } |
1da177e4 LT |
403 | fput(f); |
404 | return error; | |
405 | } | |
406 | ||
407 | /* | |
408 | * Extended attribute GET operations | |
409 | */ | |
410 | static ssize_t | |
8f0cfa52 DH |
411 | getxattr(struct dentry *d, const char __user *name, void __user *value, |
412 | size_t size) | |
1da177e4 LT |
413 | { |
414 | ssize_t error; | |
415 | void *kvalue = NULL; | |
416 | char kname[XATTR_NAME_MAX + 1]; | |
417 | ||
418 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
419 | if (error == 0 || error == sizeof(kname)) | |
420 | error = -ERANGE; | |
421 | if (error < 0) | |
422 | return error; | |
423 | ||
424 | if (size) { | |
425 | if (size > XATTR_SIZE_MAX) | |
426 | size = XATTR_SIZE_MAX; | |
d381d8a9 | 427 | kvalue = kzalloc(size, GFP_KERNEL); |
1da177e4 LT |
428 | if (!kvalue) |
429 | return -ENOMEM; | |
430 | } | |
431 | ||
5be196e5 | 432 | error = vfs_getxattr(d, kname, kvalue, size); |
f549d6c1 SS |
433 | if (error > 0) { |
434 | if (size && copy_to_user(value, kvalue, error)) | |
435 | error = -EFAULT; | |
436 | } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) { | |
437 | /* The file system tried to returned a value bigger | |
438 | than XATTR_SIZE_MAX bytes. Not possible. */ | |
439 | error = -E2BIG; | |
1da177e4 | 440 | } |
f99d49ad | 441 | kfree(kvalue); |
1da177e4 LT |
442 | return error; |
443 | } | |
444 | ||
64fd1de3 HC |
445 | SYSCALL_DEFINE4(getxattr, const char __user *, pathname, |
446 | const char __user *, name, void __user *, value, size_t, size) | |
1da177e4 | 447 | { |
2d8f3038 | 448 | struct path path; |
1da177e4 LT |
449 | ssize_t error; |
450 | ||
2d8f3038 | 451 | error = user_path(pathname, &path); |
1da177e4 LT |
452 | if (error) |
453 | return error; | |
2d8f3038 AV |
454 | error = getxattr(path.dentry, name, value, size); |
455 | path_put(&path); | |
1da177e4 LT |
456 | return error; |
457 | } | |
458 | ||
64fd1de3 HC |
459 | SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname, |
460 | const char __user *, name, void __user *, value, size_t, size) | |
1da177e4 | 461 | { |
2d8f3038 | 462 | struct path path; |
1da177e4 LT |
463 | ssize_t error; |
464 | ||
2d8f3038 | 465 | error = user_lpath(pathname, &path); |
1da177e4 LT |
466 | if (error) |
467 | return error; | |
2d8f3038 AV |
468 | error = getxattr(path.dentry, name, value, size); |
469 | path_put(&path); | |
1da177e4 LT |
470 | return error; |
471 | } | |
472 | ||
64fd1de3 HC |
473 | SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name, |
474 | void __user *, value, size_t, size) | |
1da177e4 LT |
475 | { |
476 | struct file *f; | |
477 | ssize_t error = -EBADF; | |
478 | ||
479 | f = fget(fd); | |
480 | if (!f) | |
481 | return error; | |
5a190ae6 | 482 | audit_inode(NULL, f->f_path.dentry); |
0f7fc9e4 | 483 | error = getxattr(f->f_path.dentry, name, value, size); |
1da177e4 LT |
484 | fput(f); |
485 | return error; | |
486 | } | |
487 | ||
488 | /* | |
489 | * Extended attribute LIST operations | |
490 | */ | |
491 | static ssize_t | |
492 | listxattr(struct dentry *d, char __user *list, size_t size) | |
493 | { | |
494 | ssize_t error; | |
495 | char *klist = NULL; | |
0d08d7b7 | 496 | char *vlist = NULL; /* If non-NULL, we used vmalloc() */ |
1da177e4 LT |
497 | |
498 | if (size) { | |
499 | if (size > XATTR_LIST_MAX) | |
500 | size = XATTR_LIST_MAX; | |
703bf2d1 | 501 | klist = kmalloc(size, __GFP_NOWARN | GFP_KERNEL); |
0d08d7b7 AM |
502 | if (!klist) { |
503 | vlist = vmalloc(size); | |
504 | if (!vlist) | |
505 | return -ENOMEM; | |
506 | klist = vlist; | |
507 | } | |
1da177e4 LT |
508 | } |
509 | ||
659564c8 | 510 | error = vfs_listxattr(d, klist, size); |
f549d6c1 SS |
511 | if (error > 0) { |
512 | if (size && copy_to_user(list, klist, error)) | |
513 | error = -EFAULT; | |
514 | } else if (error == -ERANGE && size >= XATTR_LIST_MAX) { | |
515 | /* The file system tried to returned a list bigger | |
516 | than XATTR_LIST_MAX bytes. Not possible. */ | |
517 | error = -E2BIG; | |
1da177e4 | 518 | } |
0d08d7b7 AM |
519 | if (vlist) |
520 | vfree(vlist); | |
521 | else | |
522 | kfree(klist); | |
1da177e4 LT |
523 | return error; |
524 | } | |
525 | ||
64fd1de3 HC |
526 | SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list, |
527 | size_t, size) | |
1da177e4 | 528 | { |
2d8f3038 | 529 | struct path path; |
1da177e4 LT |
530 | ssize_t error; |
531 | ||
2d8f3038 | 532 | error = user_path(pathname, &path); |
1da177e4 LT |
533 | if (error) |
534 | return error; | |
2d8f3038 AV |
535 | error = listxattr(path.dentry, list, size); |
536 | path_put(&path); | |
1da177e4 LT |
537 | return error; |
538 | } | |
539 | ||
64fd1de3 HC |
540 | SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list, |
541 | size_t, size) | |
1da177e4 | 542 | { |
2d8f3038 | 543 | struct path path; |
1da177e4 LT |
544 | ssize_t error; |
545 | ||
2d8f3038 | 546 | error = user_lpath(pathname, &path); |
1da177e4 LT |
547 | if (error) |
548 | return error; | |
2d8f3038 AV |
549 | error = listxattr(path.dentry, list, size); |
550 | path_put(&path); | |
1da177e4 LT |
551 | return error; |
552 | } | |
553 | ||
64fd1de3 | 554 | SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size) |
1da177e4 LT |
555 | { |
556 | struct file *f; | |
557 | ssize_t error = -EBADF; | |
558 | ||
559 | f = fget(fd); | |
560 | if (!f) | |
561 | return error; | |
5a190ae6 | 562 | audit_inode(NULL, f->f_path.dentry); |
0f7fc9e4 | 563 | error = listxattr(f->f_path.dentry, list, size); |
1da177e4 LT |
564 | fput(f); |
565 | return error; | |
566 | } | |
567 | ||
568 | /* | |
569 | * Extended attribute REMOVE operations | |
570 | */ | |
571 | static long | |
8f0cfa52 | 572 | removexattr(struct dentry *d, const char __user *name) |
1da177e4 LT |
573 | { |
574 | int error; | |
575 | char kname[XATTR_NAME_MAX + 1]; | |
576 | ||
577 | error = strncpy_from_user(kname, name, sizeof(kname)); | |
578 | if (error == 0 || error == sizeof(kname)) | |
579 | error = -ERANGE; | |
580 | if (error < 0) | |
581 | return error; | |
582 | ||
5be196e5 | 583 | return vfs_removexattr(d, kname); |
1da177e4 LT |
584 | } |
585 | ||
64fd1de3 HC |
586 | SYSCALL_DEFINE2(removexattr, const char __user *, pathname, |
587 | const char __user *, name) | |
1da177e4 | 588 | { |
2d8f3038 | 589 | struct path path; |
1da177e4 LT |
590 | int error; |
591 | ||
2d8f3038 | 592 | error = user_path(pathname, &path); |
1da177e4 LT |
593 | if (error) |
594 | return error; | |
2d8f3038 | 595 | error = mnt_want_write(path.mnt); |
18f335af | 596 | if (!error) { |
2d8f3038 AV |
597 | error = removexattr(path.dentry, name); |
598 | mnt_drop_write(path.mnt); | |
18f335af | 599 | } |
2d8f3038 | 600 | path_put(&path); |
1da177e4 LT |
601 | return error; |
602 | } | |
603 | ||
6a6160a7 HC |
604 | SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname, |
605 | const char __user *, name) | |
1da177e4 | 606 | { |
2d8f3038 | 607 | struct path path; |
1da177e4 LT |
608 | int error; |
609 | ||
2d8f3038 | 610 | error = user_lpath(pathname, &path); |
1da177e4 LT |
611 | if (error) |
612 | return error; | |
2d8f3038 | 613 | error = mnt_want_write(path.mnt); |
18f335af | 614 | if (!error) { |
2d8f3038 AV |
615 | error = removexattr(path.dentry, name); |
616 | mnt_drop_write(path.mnt); | |
18f335af | 617 | } |
2d8f3038 | 618 | path_put(&path); |
1da177e4 LT |
619 | return error; |
620 | } | |
621 | ||
6a6160a7 | 622 | SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name) |
1da177e4 LT |
623 | { |
624 | struct file *f; | |
73241ccc | 625 | struct dentry *dentry; |
1da177e4 LT |
626 | int error = -EBADF; |
627 | ||
628 | f = fget(fd); | |
629 | if (!f) | |
630 | return error; | |
0f7fc9e4 | 631 | dentry = f->f_path.dentry; |
5a190ae6 | 632 | audit_inode(NULL, dentry); |
96029c4e | 633 | error = mnt_want_write_file(f); |
18f335af DH |
634 | if (!error) { |
635 | error = removexattr(dentry, name); | |
2a79f17e | 636 | mnt_drop_write_file(f); |
18f335af | 637 | } |
1da177e4 LT |
638 | fput(f); |
639 | return error; | |
640 | } | |
641 | ||
642 | ||
643 | static const char * | |
644 | strcmp_prefix(const char *a, const char *a_prefix) | |
645 | { | |
646 | while (*a_prefix && *a == *a_prefix) { | |
647 | a++; | |
648 | a_prefix++; | |
649 | } | |
650 | return *a_prefix ? NULL : a; | |
651 | } | |
652 | ||
653 | /* | |
654 | * In order to implement different sets of xattr operations for each xattr | |
655 | * prefix with the generic xattr API, a filesystem should create a | |
656 | * null-terminated array of struct xattr_handler (one for each prefix) and | |
657 | * hang a pointer to it off of the s_xattr field of the superblock. | |
658 | * | |
659 | * The generic_fooxattr() functions will use this list to dispatch xattr | |
660 | * operations to the correct xattr_handler. | |
661 | */ | |
662 | #define for_each_xattr_handler(handlers, handler) \ | |
663 | for ((handler) = *(handlers)++; \ | |
664 | (handler) != NULL; \ | |
665 | (handler) = *(handlers)++) | |
666 | ||
667 | /* | |
668 | * Find the xattr_handler with the matching prefix. | |
669 | */ | |
bb435453 SH |
670 | static const struct xattr_handler * |
671 | xattr_resolve_name(const struct xattr_handler **handlers, const char **name) | |
1da177e4 | 672 | { |
bb435453 | 673 | const struct xattr_handler *handler; |
1da177e4 LT |
674 | |
675 | if (!*name) | |
676 | return NULL; | |
677 | ||
678 | for_each_xattr_handler(handlers, handler) { | |
679 | const char *n = strcmp_prefix(*name, handler->prefix); | |
680 | if (n) { | |
681 | *name = n; | |
682 | break; | |
683 | } | |
684 | } | |
685 | return handler; | |
686 | } | |
687 | ||
688 | /* | |
689 | * Find the handler for the prefix and dispatch its get() operation. | |
690 | */ | |
691 | ssize_t | |
692 | generic_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size) | |
693 | { | |
bb435453 | 694 | const struct xattr_handler *handler; |
1da177e4 | 695 | |
431547b3 | 696 | handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name); |
1da177e4 LT |
697 | if (!handler) |
698 | return -EOPNOTSUPP; | |
431547b3 | 699 | return handler->get(dentry, name, buffer, size, handler->flags); |
1da177e4 LT |
700 | } |
701 | ||
702 | /* | |
703 | * Combine the results of the list() operation from every xattr_handler in the | |
704 | * list. | |
705 | */ | |
706 | ssize_t | |
707 | generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) | |
708 | { | |
bb435453 | 709 | const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr; |
1da177e4 LT |
710 | unsigned int size = 0; |
711 | ||
712 | if (!buffer) { | |
431547b3 CH |
713 | for_each_xattr_handler(handlers, handler) { |
714 | size += handler->list(dentry, NULL, 0, NULL, 0, | |
715 | handler->flags); | |
716 | } | |
1da177e4 LT |
717 | } else { |
718 | char *buf = buffer; | |
719 | ||
720 | for_each_xattr_handler(handlers, handler) { | |
431547b3 CH |
721 | size = handler->list(dentry, buf, buffer_size, |
722 | NULL, 0, handler->flags); | |
1da177e4 LT |
723 | if (size > buffer_size) |
724 | return -ERANGE; | |
725 | buf += size; | |
726 | buffer_size -= size; | |
727 | } | |
728 | size = buf - buffer; | |
729 | } | |
730 | return size; | |
731 | } | |
732 | ||
733 | /* | |
734 | * Find the handler for the prefix and dispatch its set() operation. | |
735 | */ | |
736 | int | |
737 | generic_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags) | |
738 | { | |
bb435453 | 739 | const struct xattr_handler *handler; |
1da177e4 LT |
740 | |
741 | if (size == 0) | |
742 | value = ""; /* empty EA, do not remove */ | |
431547b3 | 743 | handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name); |
1da177e4 LT |
744 | if (!handler) |
745 | return -EOPNOTSUPP; | |
df7e1303 | 746 | return handler->set(dentry, name, value, size, flags, handler->flags); |
1da177e4 LT |
747 | } |
748 | ||
749 | /* | |
750 | * Find the handler for the prefix and dispatch its set() operation to remove | |
751 | * any associated extended attribute. | |
752 | */ | |
753 | int | |
754 | generic_removexattr(struct dentry *dentry, const char *name) | |
755 | { | |
bb435453 | 756 | const struct xattr_handler *handler; |
1da177e4 | 757 | |
431547b3 | 758 | handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name); |
1da177e4 LT |
759 | if (!handler) |
760 | return -EOPNOTSUPP; | |
431547b3 CH |
761 | return handler->set(dentry, name, NULL, 0, |
762 | XATTR_REPLACE, handler->flags); | |
1da177e4 LT |
763 | } |
764 | ||
765 | EXPORT_SYMBOL(generic_getxattr); | |
766 | EXPORT_SYMBOL(generic_listxattr); | |
767 | EXPORT_SYMBOL(generic_setxattr); | |
768 | EXPORT_SYMBOL(generic_removexattr); |