Blame view
fs/xattr.c
23.5 KB
1da177e4c
|
1 2 3 4 5 6 7 8 9 10 11 |
/* File: fs/xattr.c Extended attribute handling. Copyright (C) 2001 by Andreas Gruenbacher <a.gruenbacher@computer.org> Copyright (C) 2001 SGI - Silicon Graphics, Inc <linux-xfs@oss.sgi.com> Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com> */ #include <linux/fs.h> #include <linux/slab.h> |
1da177e4c
|
12 13 |
#include <linux/file.h> #include <linux/xattr.h> |
18f335aff
|
14 |
#include <linux/mount.h> |
1da177e4c
|
15 16 |
#include <linux/namei.h> #include <linux/security.h> |
c7b87de23
|
17 |
#include <linux/evm.h> |
1da177e4c
|
18 |
#include <linux/syscalls.h> |
630d9c472
|
19 |
#include <linux/export.h> |
0eeca2830
|
20 |
#include <linux/fsnotify.h> |
73241ccca
|
21 |
#include <linux/audit.h> |
0d08d7b7e
|
22 |
#include <linux/vmalloc.h> |
2f6f0654a
|
23 |
#include <linux/posix_acl_xattr.h> |
1da177e4c
|
24 |
|
0d08d7b7e
|
25 |
#include <asm/uaccess.h> |
5be196e5f
|
26 |
|
b6ba11773
|
27 28 29 30 31 32 33 34 35 36 37 38 |
static const char * strcmp_prefix(const char *a, const char *a_prefix) { while (*a_prefix && *a == *a_prefix) { a++; a_prefix++; } return *a_prefix ? NULL : a; } /* * In order to implement different sets of xattr operations for each xattr |
6c6ef9f26
|
39 40 41 |
* prefix, a filesystem should create a null-terminated array of struct * xattr_handler (one for each prefix) and hang a pointer to it off of the * s_xattr field of the superblock. |
b6ba11773
|
42 43 44 45 46 47 48 49 50 51 52 |
*/ #define for_each_xattr_handler(handlers, handler) \ if (handlers) \ for ((handler) = *(handlers)++; \ (handler) != NULL; \ (handler) = *(handlers)++) /* * Find the xattr_handler with the matching prefix. */ static const struct xattr_handler * |
d0a5b995a
|
53 |
xattr_resolve_name(struct inode *inode, const char **name) |
b6ba11773
|
54 |
{ |
d0a5b995a
|
55 |
const struct xattr_handler **handlers = inode->i_sb->s_xattr; |
b6ba11773
|
56 |
const struct xattr_handler *handler; |
5f6e59ae8
|
57 58 59 |
if (!(inode->i_opflags & IOP_XATTR)) { if (unlikely(is_bad_inode(inode))) return ERR_PTR(-EIO); |
d0a5b995a
|
60 |
return ERR_PTR(-EOPNOTSUPP); |
5f6e59ae8
|
61 |
} |
b6ba11773
|
62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 |
for_each_xattr_handler(handlers, handler) { const char *n; n = strcmp_prefix(*name, xattr_prefix(handler)); if (n) { if (!handler->prefix ^ !*n) { if (*n) continue; return ERR_PTR(-EINVAL); } *name = n; return handler; } } return ERR_PTR(-EOPNOTSUPP); } |
e0ad7b073
|
78 79 80 81 82 83 84 85 86 87 88 89 |
/* * Check permissions for extended attribute access. This is a bit complicated * because different namespaces have very different rules. */ static int xattr_permission(struct inode *inode, const char *name, int mask) { /* * We can never set or remove an extended attribute on a read-only * filesystem or on an immutable / append-only inode. */ if (mask & MAY_WRITE) { |
e0ad7b073
|
90 91 |
if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) return -EPERM; |
0bd23d09b
|
92 93 94 95 96 97 98 |
/* * Updating an xattr will likely cause i_uid and i_gid * to be writen back improperly if their true value is * unknown to the vfs. */ if (HAS_UNMAPPED_ID(inode)) return -EPERM; |
e0ad7b073
|
99 100 101 102 103 104 105 106 107 108 109 |
} /* * No restriction for security.* and system.* from the VFS. Decision * on these is left to the underlying filesystem / security module. */ if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) || !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) return 0; /* |
55b23bde1
|
110 |
* The trusted.* namespace can only be accessed by privileged users. |
e0ad7b073
|
111 |
*/ |
55b23bde1
|
112 113 114 115 116 |
if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) { if (!capable(CAP_SYS_ADMIN)) return (mask & MAY_WRITE) ? -EPERM : -ENODATA; return 0; } |
e0ad7b073
|
117 |
|
55b23bde1
|
118 119 |
/* * In the user.* namespace, only regular files and directories can have |
f1f2d8713
|
120 |
* extended attributes. For sticky directories, only the owner and |
55b23bde1
|
121 |
* privileged users can write attributes. |
f1f2d8713
|
122 |
*/ |
e0ad7b073
|
123 |
if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) { |
f1f2d8713
|
124 |
if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode)) |
55b23bde1
|
125 |
return (mask & MAY_WRITE) ? -EPERM : -ENODATA; |
f1f2d8713
|
126 |
if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) && |
2e1496707
|
127 |
(mask & MAY_WRITE) && !inode_owner_or_capable(inode)) |
e0ad7b073
|
128 129 |
return -EPERM; } |
f419a2e3b
|
130 |
return inode_permission(inode, mask); |
e0ad7b073
|
131 |
} |
5d6c31910
|
132 133 134 135 |
int __vfs_setxattr(struct dentry *dentry, struct inode *inode, const char *name, const void *value, size_t size, int flags) { |
6c6ef9f26
|
136 137 138 139 140 141 |
const struct xattr_handler *handler; handler = xattr_resolve_name(inode, &name); if (IS_ERR(handler)) return PTR_ERR(handler); if (!handler->set) |
5d6c31910
|
142 |
return -EOPNOTSUPP; |
6c6ef9f26
|
143 144 145 |
if (size == 0) value = ""; /* empty EA, do not remove */ return handler->set(handler, dentry, inode, name, value, size, flags); |
5d6c31910
|
146 147 |
} EXPORT_SYMBOL(__vfs_setxattr); |
b1ab7e4b2
|
148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 |
/** * __vfs_setxattr_noperm - perform setxattr operation without performing * permission checks. * * @dentry - object to perform setxattr on * @name - xattr name to set * @value - value to set @name to * @size - size of @value * @flags - flags to pass into filesystem operations * * returns the result of the internal setxattr or setsecurity operations. * * This function requires the caller to lock the inode's i_mutex before it * is executed. It also assumes that the caller will make the appropriate * permission checks. */ int __vfs_setxattr_noperm(struct dentry *dentry, const char *name, const void *value, size_t size, int flags) |
5be196e5f
|
166 167 |
{ struct inode *inode = dentry->d_inode; |
4a5901537
|
168 |
int error = -EAGAIN; |
69b457329
|
169 170 |
int issec = !strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN); |
e0ad7b073
|
171 |
|
69b457329
|
172 173 |
if (issec) inode->i_flags &= ~S_NOSEC; |
6c6ef9f26
|
174 |
if (inode->i_opflags & IOP_XATTR) { |
5d6c31910
|
175 |
error = __vfs_setxattr(dentry, inode, name, value, size, flags); |
5be196e5f
|
176 177 178 179 180 |
if (!error) { fsnotify_xattr(dentry); security_inode_post_setxattr(dentry, name, value, size, flags); } |
4a5901537
|
181 |
} else { |
5f6e59ae8
|
182 183 |
if (unlikely(is_bad_inode(inode))) return -EIO; |
4a5901537
|
184 185 186 187 188 189 190 191 192 193 194 195 |
} if (error == -EAGAIN) { error = -EOPNOTSUPP; if (issec) { const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; error = security_inode_setsecurity(inode, suffix, value, size, flags); if (!error) fsnotify_xattr(dentry); } |
5be196e5f
|
196 |
} |
b1ab7e4b2
|
197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 |
return error; } int vfs_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags) { struct inode *inode = dentry->d_inode; int error; error = xattr_permission(inode, name, MAY_WRITE); if (error) return error; |
5955102c9
|
212 |
inode_lock(inode); |
b1ab7e4b2
|
213 214 215 216 217 |
error = security_inode_setxattr(dentry, name, value, size, flags); if (error) goto out; error = __vfs_setxattr_noperm(dentry, name, value, size, flags); |
5be196e5f
|
218 |
out: |
5955102c9
|
219 |
inode_unlock(inode); |
5be196e5f
|
220 221 222 223 224 |
return error; } EXPORT_SYMBOL_GPL(vfs_setxattr); ssize_t |
424925940
|
225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 |
xattr_getsecurity(struct inode *inode, const char *name, void *value, size_t size) { void *buffer = NULL; ssize_t len; if (!value || !size) { len = security_inode_getsecurity(inode, name, &buffer, false); goto out_noalloc; } len = security_inode_getsecurity(inode, name, &buffer, true); if (len < 0) return len; if (size < len) { len = -ERANGE; goto out; } memcpy(value, buffer, len); out: security_release_secctx(buffer, len); out_noalloc: return len; } EXPORT_SYMBOL_GPL(xattr_getsecurity); |
1601fbad2
|
250 251 252 253 254 255 256 257 258 259 260 261 |
/* * vfs_getxattr_alloc - allocate memory, if necessary, before calling getxattr * * Allocate memory, if not already allocated, or re-allocate correct size, * before retrieving the extended attribute. * * Returns the result of alloc, if failed, or the getxattr operation. */ ssize_t vfs_getxattr_alloc(struct dentry *dentry, const char *name, char **xattr_value, size_t xattr_size, gfp_t flags) { |
6c6ef9f26
|
262 |
const struct xattr_handler *handler; |
1601fbad2
|
263 264 265 266 267 268 269 |
struct inode *inode = dentry->d_inode; char *value = *xattr_value; int error; error = xattr_permission(inode, name, MAY_READ); if (error) return error; |
6c6ef9f26
|
270 271 272 273 |
handler = xattr_resolve_name(inode, &name); if (IS_ERR(handler)) return PTR_ERR(handler); if (!handler->get) |
1601fbad2
|
274 |
return -EOPNOTSUPP; |
6c6ef9f26
|
275 |
error = handler->get(handler, dentry, inode, name, NULL, 0); |
1601fbad2
|
276 277 278 279 280 281 282 283 284 |
if (error < 0) return error; if (!value || (error > xattr_size)) { value = krealloc(*xattr_value, error + 1, flags); if (!value) return -ENOMEM; memset(value, 0, error + 1); } |
6c6ef9f26
|
285 |
error = handler->get(handler, dentry, inode, name, value, error); |
1601fbad2
|
286 287 288 |
*xattr_value = value; return error; } |
424925940
|
289 |
ssize_t |
5d6c31910
|
290 291 292 |
__vfs_getxattr(struct dentry *dentry, struct inode *inode, const char *name, void *value, size_t size) { |
6c6ef9f26
|
293 294 295 296 297 298 |
const struct xattr_handler *handler; handler = xattr_resolve_name(inode, &name); if (IS_ERR(handler)) return PTR_ERR(handler); if (!handler->get) |
5d6c31910
|
299 |
return -EOPNOTSUPP; |
6c6ef9f26
|
300 |
return handler->get(handler, dentry, inode, name, value, size); |
5d6c31910
|
301 302 303 304 |
} EXPORT_SYMBOL(__vfs_getxattr); ssize_t |
8f0cfa52a
|
305 |
vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size) |
5be196e5f
|
306 307 308 |
{ struct inode *inode = dentry->d_inode; int error; |
e0ad7b073
|
309 310 311 |
error = xattr_permission(inode, name, MAY_READ); if (error) return error; |
5be196e5f
|
312 313 314 |
error = security_inode_getxattr(dentry, name); if (error) return error; |
5be196e5f
|
315 |
if (!strncmp(name, XATTR_SECURITY_PREFIX, |
e0ad7b073
|
316 317 |
XATTR_SECURITY_PREFIX_LEN)) { const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; |
424925940
|
318 |
int ret = xattr_getsecurity(inode, suffix, value, size); |
5be196e5f
|
319 320 321 322 |
/* * Only overwrite the return value if a security module * is actually active. */ |
4bea58053
|
323 324 325 |
if (ret == -EOPNOTSUPP) goto nolsm; return ret; |
5be196e5f
|
326 |
} |
4bea58053
|
327 |
nolsm: |
5d6c31910
|
328 |
return __vfs_getxattr(dentry, inode, name, value, size); |
5be196e5f
|
329 330 |
} EXPORT_SYMBOL_GPL(vfs_getxattr); |
659564c8a
|
331 |
ssize_t |
bf3ee7136
|
332 |
vfs_listxattr(struct dentry *dentry, char *list, size_t size) |
659564c8a
|
333 |
{ |
bf3ee7136
|
334 |
struct inode *inode = d_inode(dentry); |
659564c8a
|
335 |
ssize_t error; |
bf3ee7136
|
336 |
error = security_inode_listxattr(dentry); |
659564c8a
|
337 338 |
if (error) return error; |
bf3ee7136
|
339 340 341 |
if (inode->i_op->listxattr && (inode->i_opflags & IOP_XATTR)) { error = -EOPNOTSUPP; error = inode->i_op->listxattr(dentry, list, size); |
659564c8a
|
342 |
} else { |
bf3ee7136
|
343 |
error = security_inode_listsecurity(inode, list, size); |
659564c8a
|
344 345 346 347 348 349 |
if (size && error > size) error = -ERANGE; } return error; } EXPORT_SYMBOL_GPL(vfs_listxattr); |
5be196e5f
|
350 |
int |
5d6c31910
|
351 |
__vfs_removexattr(struct dentry *dentry, const char *name) |
5be196e5f
|
352 |
{ |
6c6ef9f26
|
353 354 |
struct inode *inode = d_inode(dentry); const struct xattr_handler *handler; |
5be196e5f
|
355 |
|
6c6ef9f26
|
356 357 358 359 |
handler = xattr_resolve_name(inode, &name); if (IS_ERR(handler)) return PTR_ERR(handler); if (!handler->set) |
5be196e5f
|
360 |
return -EOPNOTSUPP; |
6c6ef9f26
|
361 |
return handler->set(handler, dentry, inode, name, NULL, 0, XATTR_REPLACE); |
5d6c31910
|
362 363 364 365 366 367 368 369 |
} EXPORT_SYMBOL(__vfs_removexattr); int vfs_removexattr(struct dentry *dentry, const char *name) { struct inode *inode = dentry->d_inode; int error; |
5be196e5f
|
370 |
|
e0ad7b073
|
371 372 373 |
error = xattr_permission(inode, name, MAY_WRITE); if (error) return error; |
5955102c9
|
374 |
inode_lock(inode); |
5be196e5f
|
375 |
error = security_inode_removexattr(dentry, name); |
7c51bb00c
|
376 377 |
if (error) goto out; |
5be196e5f
|
378 |
|
5d6c31910
|
379 |
error = __vfs_removexattr(dentry, name); |
5be196e5f
|
380 |
|
c7b87de23
|
381 |
if (!error) { |
5be196e5f
|
382 |
fsnotify_xattr(dentry); |
c7b87de23
|
383 384 |
evm_inode_post_removexattr(dentry, name); } |
7c51bb00c
|
385 386 |
out: |
5955102c9
|
387 |
inode_unlock(inode); |
5be196e5f
|
388 389 390 |
return error; } EXPORT_SYMBOL_GPL(vfs_removexattr); |
1da177e4c
|
391 392 393 394 |
/* * Extended attribute SET operations */ static long |
8f0cfa52a
|
395 |
setxattr(struct dentry *d, const char __user *name, const void __user *value, |
1da177e4c
|
396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 |
size_t size, int flags) { int error; void *kvalue = NULL; char kname[XATTR_NAME_MAX + 1]; if (flags & ~(XATTR_CREATE|XATTR_REPLACE)) return -EINVAL; error = strncpy_from_user(kname, name, sizeof(kname)); if (error == 0 || error == sizeof(kname)) error = -ERANGE; if (error < 0) return error; if (size) { if (size > XATTR_SIZE_MAX) return -E2BIG; |
44c824982
|
414 415 |
kvalue = kmalloc(size, GFP_KERNEL | __GFP_NOWARN); if (!kvalue) { |
0b2a6f231
|
416 417 |
kvalue = vmalloc(size); if (!kvalue) |
44c824982
|
418 |
return -ENOMEM; |
44c824982
|
419 420 421 422 423 |
} if (copy_from_user(kvalue, value, size)) { error = -EFAULT; goto out; } |
2f6f0654a
|
424 425 426 |
if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) || (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)) posix_acl_fix_xattr_from_user(kvalue, size); |
1da177e4c
|
427 |
} |
5be196e5f
|
428 |
error = vfs_setxattr(d, kname, kvalue, size, flags); |
44c824982
|
429 |
out: |
0b2a6f231
|
430 |
kvfree(kvalue); |
1da177e4c
|
431 432 |
return error; } |
8cc431165
|
433 434 435 |
static int path_setxattr(const char __user *pathname, const char __user *name, const void __user *value, size_t size, int flags, unsigned int lookup_flags) |
1da177e4c
|
436 |
{ |
2d8f30380
|
437 |
struct path path; |
1da177e4c
|
438 |
int error; |
68f1bb8bb
|
439 440 |
retry: error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); |
1da177e4c
|
441 442 |
if (error) return error; |
2d8f30380
|
443 |
error = mnt_want_write(path.mnt); |
18f335aff
|
444 |
if (!error) { |
2d8f30380
|
445 446 |
error = setxattr(path.dentry, name, value, size, flags); mnt_drop_write(path.mnt); |
18f335aff
|
447 |
} |
2d8f30380
|
448 |
path_put(&path); |
68f1bb8bb
|
449 450 451 452 |
if (retry_estale(error, lookup_flags)) { lookup_flags |= LOOKUP_REVAL; goto retry; } |
1da177e4c
|
453 454 |
return error; } |
8cc431165
|
455 456 457 458 459 460 |
SYSCALL_DEFINE5(setxattr, const char __user *, pathname, const char __user *, name, const void __user *, value, size_t, size, int, flags) { return path_setxattr(pathname, name, value, size, flags, LOOKUP_FOLLOW); } |
64fd1de3d
|
461 462 463 |
SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname, const char __user *, name, const void __user *, value, size_t, size, int, flags) |
1da177e4c
|
464 |
{ |
8cc431165
|
465 |
return path_setxattr(pathname, name, value, size, flags, 0); |
1da177e4c
|
466 |
} |
64fd1de3d
|
467 468 |
SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name, const void __user *,value, size_t, size, int, flags) |
1da177e4c
|
469 |
{ |
2903ff019
|
470 |
struct fd f = fdget(fd); |
1da177e4c
|
471 |
int error = -EBADF; |
2903ff019
|
472 |
if (!f.file) |
1da177e4c
|
473 |
return error; |
9f45f5bf3
|
474 |
audit_file(f.file); |
2903ff019
|
475 |
error = mnt_want_write_file(f.file); |
18f335aff
|
476 |
if (!error) { |
9f45f5bf3
|
477 |
error = setxattr(f.file->f_path.dentry, name, value, size, flags); |
2903ff019
|
478 |
mnt_drop_write_file(f.file); |
18f335aff
|
479 |
} |
2903ff019
|
480 |
fdput(f); |
1da177e4c
|
481 482 483 484 485 486 487 |
return error; } /* * Extended attribute GET operations */ static ssize_t |
8f0cfa52a
|
488 489 |
getxattr(struct dentry *d, const char __user *name, void __user *value, size_t size) |
1da177e4c
|
490 491 492 493 494 495 496 497 498 499 500 501 502 503 |
{ ssize_t error; void *kvalue = NULL; char kname[XATTR_NAME_MAX + 1]; error = strncpy_from_user(kname, name, sizeof(kname)); if (error == 0 || error == sizeof(kname)) error = -ERANGE; if (error < 0) return error; if (size) { if (size > XATTR_SIZE_MAX) size = XATTR_SIZE_MAX; |
779302e67
|
504 505 |
kvalue = kzalloc(size, GFP_KERNEL | __GFP_NOWARN); if (!kvalue) { |
0b2a6f231
|
506 507 |
kvalue = vmalloc(size); if (!kvalue) |
779302e67
|
508 |
return -ENOMEM; |
779302e67
|
509 |
} |
1da177e4c
|
510 |
} |
5be196e5f
|
511 |
error = vfs_getxattr(d, kname, kvalue, size); |
f549d6c18
|
512 |
if (error > 0) { |
2f6f0654a
|
513 514 515 |
if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) || (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)) posix_acl_fix_xattr_to_user(kvalue, size); |
f549d6c18
|
516 517 518 519 520 521 |
if (size && copy_to_user(value, kvalue, error)) error = -EFAULT; } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) { /* The file system tried to returned a value bigger than XATTR_SIZE_MAX bytes. Not possible. */ error = -E2BIG; |
1da177e4c
|
522 |
} |
0b2a6f231
|
523 524 |
kvfree(kvalue); |
1da177e4c
|
525 526 |
return error; } |
8cc431165
|
527 528 529 |
static ssize_t path_getxattr(const char __user *pathname, const char __user *name, void __user *value, size_t size, unsigned int lookup_flags) |
1da177e4c
|
530 |
{ |
2d8f30380
|
531 |
struct path path; |
1da177e4c
|
532 |
ssize_t error; |
60e66b48c
|
533 534 |
retry: error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); |
1da177e4c
|
535 536 |
if (error) return error; |
2d8f30380
|
537 538 |
error = getxattr(path.dentry, name, value, size); path_put(&path); |
60e66b48c
|
539 540 541 542 |
if (retry_estale(error, lookup_flags)) { lookup_flags |= LOOKUP_REVAL; goto retry; } |
1da177e4c
|
543 544 |
return error; } |
8cc431165
|
545 546 547 548 549 |
SYSCALL_DEFINE4(getxattr, const char __user *, pathname, const char __user *, name, void __user *, value, size_t, size) { return path_getxattr(pathname, name, value, size, LOOKUP_FOLLOW); } |
64fd1de3d
|
550 551 |
SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname, const char __user *, name, void __user *, value, size_t, size) |
1da177e4c
|
552 |
{ |
8cc431165
|
553 |
return path_getxattr(pathname, name, value, size, 0); |
1da177e4c
|
554 |
} |
64fd1de3d
|
555 556 |
SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name, void __user *, value, size_t, size) |
1da177e4c
|
557 |
{ |
2903ff019
|
558 |
struct fd f = fdget(fd); |
1da177e4c
|
559 |
ssize_t error = -EBADF; |
2903ff019
|
560 |
if (!f.file) |
1da177e4c
|
561 |
return error; |
9f45f5bf3
|
562 |
audit_file(f.file); |
2903ff019
|
563 564 |
error = getxattr(f.file->f_path.dentry, name, value, size); fdput(f); |
1da177e4c
|
565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 |
return error; } /* * Extended attribute LIST operations */ static ssize_t listxattr(struct dentry *d, char __user *list, size_t size) { ssize_t error; char *klist = NULL; if (size) { if (size > XATTR_LIST_MAX) size = XATTR_LIST_MAX; |
703bf2d12
|
580 |
klist = kmalloc(size, __GFP_NOWARN | GFP_KERNEL); |
0d08d7b7e
|
581 |
if (!klist) { |
0b2a6f231
|
582 583 |
klist = vmalloc(size); if (!klist) |
0d08d7b7e
|
584 |
return -ENOMEM; |
0d08d7b7e
|
585 |
} |
1da177e4c
|
586 |
} |
659564c8a
|
587 |
error = vfs_listxattr(d, klist, size); |
f549d6c18
|
588 589 590 591 592 593 594 |
if (error > 0) { if (size && copy_to_user(list, klist, error)) error = -EFAULT; } else if (error == -ERANGE && size >= XATTR_LIST_MAX) { /* The file system tried to returned a list bigger than XATTR_LIST_MAX bytes. Not possible. */ error = -E2BIG; |
1da177e4c
|
595 |
} |
0b2a6f231
|
596 597 |
kvfree(klist); |
1da177e4c
|
598 599 |
return error; } |
8cc431165
|
600 601 |
static ssize_t path_listxattr(const char __user *pathname, char __user *list, size_t size, unsigned int lookup_flags) |
1da177e4c
|
602 |
{ |
2d8f30380
|
603 |
struct path path; |
1da177e4c
|
604 |
ssize_t error; |
10a90cf36
|
605 606 |
retry: error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); |
1da177e4c
|
607 608 |
if (error) return error; |
2d8f30380
|
609 610 |
error = listxattr(path.dentry, list, size); path_put(&path); |
10a90cf36
|
611 612 613 614 |
if (retry_estale(error, lookup_flags)) { lookup_flags |= LOOKUP_REVAL; goto retry; } |
1da177e4c
|
615 616 |
return error; } |
8cc431165
|
617 618 619 620 621 |
SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list, size_t, size) { return path_listxattr(pathname, list, size, LOOKUP_FOLLOW); } |
64fd1de3d
|
622 623 |
SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list, size_t, size) |
1da177e4c
|
624 |
{ |
8cc431165
|
625 |
return path_listxattr(pathname, list, size, 0); |
1da177e4c
|
626 |
} |
64fd1de3d
|
627 |
SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size) |
1da177e4c
|
628 |
{ |
2903ff019
|
629 |
struct fd f = fdget(fd); |
1da177e4c
|
630 |
ssize_t error = -EBADF; |
2903ff019
|
631 |
if (!f.file) |
1da177e4c
|
632 |
return error; |
9f45f5bf3
|
633 |
audit_file(f.file); |
2903ff019
|
634 635 |
error = listxattr(f.file->f_path.dentry, list, size); fdput(f); |
1da177e4c
|
636 637 638 639 640 641 642 |
return error; } /* * Extended attribute REMOVE operations */ static long |
8f0cfa52a
|
643 |
removexattr(struct dentry *d, const char __user *name) |
1da177e4c
|
644 645 646 647 648 649 650 651 652 |
{ int error; char kname[XATTR_NAME_MAX + 1]; error = strncpy_from_user(kname, name, sizeof(kname)); if (error == 0 || error == sizeof(kname)) error = -ERANGE; if (error < 0) return error; |
5be196e5f
|
653 |
return vfs_removexattr(d, kname); |
1da177e4c
|
654 |
} |
8cc431165
|
655 656 |
static int path_removexattr(const char __user *pathname, const char __user *name, unsigned int lookup_flags) |
1da177e4c
|
657 |
{ |
2d8f30380
|
658 |
struct path path; |
1da177e4c
|
659 |
int error; |
12f062129
|
660 661 |
retry: error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); |
1da177e4c
|
662 663 |
if (error) return error; |
2d8f30380
|
664 |
error = mnt_want_write(path.mnt); |
18f335aff
|
665 |
if (!error) { |
2d8f30380
|
666 667 |
error = removexattr(path.dentry, name); mnt_drop_write(path.mnt); |
18f335aff
|
668 |
} |
2d8f30380
|
669 |
path_put(&path); |
12f062129
|
670 671 672 673 |
if (retry_estale(error, lookup_flags)) { lookup_flags |= LOOKUP_REVAL; goto retry; } |
1da177e4c
|
674 675 |
return error; } |
8cc431165
|
676 677 678 679 680 |
SYSCALL_DEFINE2(removexattr, const char __user *, pathname, const char __user *, name) { return path_removexattr(pathname, name, LOOKUP_FOLLOW); } |
6a6160a7b
|
681 682 |
SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname, const char __user *, name) |
1da177e4c
|
683 |
{ |
8cc431165
|
684 |
return path_removexattr(pathname, name, 0); |
1da177e4c
|
685 |
} |
6a6160a7b
|
686 |
SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name) |
1da177e4c
|
687 |
{ |
2903ff019
|
688 |
struct fd f = fdget(fd); |
1da177e4c
|
689 |
int error = -EBADF; |
2903ff019
|
690 |
if (!f.file) |
1da177e4c
|
691 |
return error; |
9f45f5bf3
|
692 |
audit_file(f.file); |
2903ff019
|
693 |
error = mnt_want_write_file(f.file); |
18f335aff
|
694 |
if (!error) { |
9f45f5bf3
|
695 |
error = removexattr(f.file->f_path.dentry, name); |
2903ff019
|
696 |
mnt_drop_write_file(f.file); |
18f335aff
|
697 |
} |
2903ff019
|
698 |
fdput(f); |
1da177e4c
|
699 700 |
return error; } |
1da177e4c
|
701 |
/* |
1da177e4c
|
702 703 704 705 706 707 |
* Combine the results of the list() operation from every xattr_handler in the * list. */ ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) { |
bb4354538
|
708 |
const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr; |
1da177e4c
|
709 710 711 |
unsigned int size = 0; if (!buffer) { |
431547b3c
|
712 |
for_each_xattr_handler(handlers, handler) { |
764a5c6b1
|
713 714 |
if (!handler->name || (handler->list && !handler->list(dentry))) |
c4803c497
|
715 |
continue; |
764a5c6b1
|
716 |
size += strlen(handler->name) + 1; |
431547b3c
|
717 |
} |
1da177e4c
|
718 719 |
} else { char *buf = buffer; |
764a5c6b1
|
720 |
size_t len; |
1da177e4c
|
721 722 |
for_each_xattr_handler(handlers, handler) { |
764a5c6b1
|
723 724 |
if (!handler->name || (handler->list && !handler->list(dentry))) |
c4803c497
|
725 |
continue; |
764a5c6b1
|
726 727 |
len = strlen(handler->name); if (len + 1 > buffer_size) |
1da177e4c
|
728 |
return -ERANGE; |
764a5c6b1
|
729 730 731 |
memcpy(buf, handler->name, len + 1); buf += len + 1; buffer_size -= len + 1; |
1da177e4c
|
732 733 734 735 736 |
} size = buf - buffer; } return size; } |
1da177e4c
|
737 |
EXPORT_SYMBOL(generic_listxattr); |
38f386574
|
738 |
|
e409de992
|
739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 |
/** * xattr_full_name - Compute full attribute name from suffix * * @handler: handler of the xattr_handler operation * @name: name passed to the xattr_handler operation * * The get and set xattr handler operations are called with the remainder of * the attribute name after skipping the handler's prefix: for example, "foo" * is passed to the get operation of a handler with prefix "user." to get * attribute "user.foo". The full name is still "there" in the name though. * * Note: the list xattr handler operation when called from the vfs is passed a * NULL name; some file systems use this operation internally, with varying * semantics. */ const char *xattr_full_name(const struct xattr_handler *handler, const char *name) { |
98e9cb571
|
757 |
size_t prefix_len = strlen(xattr_prefix(handler)); |
e409de992
|
758 759 760 761 |
return name - prefix_len; } EXPORT_SYMBOL(xattr_full_name); |
38f386574
|
762 763 764 765 766 767 768 769 770 771 |
/* * Allocate new xattr and copy in the value; but leave the name to callers. */ struct simple_xattr *simple_xattr_alloc(const void *value, size_t size) { struct simple_xattr *new_xattr; size_t len; /* wrap around? */ len = sizeof(*new_xattr) + size; |
4e66d445d
|
772 |
if (len < sizeof(*new_xattr)) |
38f386574
|
773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 |
return NULL; new_xattr = kmalloc(len, GFP_KERNEL); if (!new_xattr) return NULL; new_xattr->size = size; memcpy(new_xattr->value, value, size); return new_xattr; } /* * xattr GET operation for in-memory/pseudo filesystems */ int simple_xattr_get(struct simple_xattrs *xattrs, const char *name, void *buffer, size_t size) { struct simple_xattr *xattr; int ret = -ENODATA; spin_lock(&xattrs->lock); list_for_each_entry(xattr, &xattrs->head, list) { if (strcmp(name, xattr->name)) continue; ret = xattr->size; if (buffer) { if (size < xattr->size) ret = -ERANGE; else memcpy(buffer, xattr->value, xattr->size); } break; } spin_unlock(&xattrs->lock); return ret; } |
aa7c5241c
|
810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 |
/** * simple_xattr_set - xattr SET operation for in-memory/pseudo filesystems * @xattrs: target simple_xattr list * @name: name of the extended attribute * @value: value of the xattr. If %NULL, will remove the attribute. * @size: size of the new xattr * @flags: %XATTR_{CREATE|REPLACE} * * %XATTR_CREATE is set, the xattr shouldn't exist already; otherwise fails * with -EEXIST. If %XATTR_REPLACE is set, the xattr should exist; * otherwise, fails with -ENODATA. * * Returns 0 on success, -errno on failure. */ int simple_xattr_set(struct simple_xattrs *xattrs, const char *name, const void *value, size_t size, int flags) |
38f386574
|
826 827 |
{ struct simple_xattr *xattr; |
433858469
|
828 |
struct simple_xattr *new_xattr = NULL; |
38f386574
|
829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 |
int err = 0; /* value == NULL means remove */ if (value) { new_xattr = simple_xattr_alloc(value, size); if (!new_xattr) return -ENOMEM; new_xattr->name = kstrdup(name, GFP_KERNEL); if (!new_xattr->name) { kfree(new_xattr); return -ENOMEM; } } spin_lock(&xattrs->lock); list_for_each_entry(xattr, &xattrs->head, list) { if (!strcmp(name, xattr->name)) { if (flags & XATTR_CREATE) { xattr = new_xattr; err = -EEXIST; } else if (new_xattr) { list_replace(&xattr->list, &new_xattr->list); } else { list_del(&xattr->list); } goto out; } } if (flags & XATTR_REPLACE) { xattr = new_xattr; err = -ENODATA; } else { list_add(&new_xattr->list, &xattrs->head); xattr = NULL; } out: spin_unlock(&xattrs->lock); if (xattr) { kfree(xattr->name); kfree(xattr); } return err; } |
38f386574
|
874 875 876 877 |
static bool xattr_is_trusted(const char *name) { return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN); } |
786534b92
|
878 879 880 881 882 883 884 885 886 887 888 889 890 |
static int xattr_list_one(char **buffer, ssize_t *remaining_size, const char *name) { size_t len = strlen(name) + 1; if (*buffer) { if (*remaining_size < len) return -ERANGE; memcpy(*buffer, name, len); *buffer += len; } *remaining_size -= len; return 0; } |
38f386574
|
891 892 893 |
/* * xattr LIST operation for in-memory/pseudo filesystems */ |
786534b92
|
894 895 |
ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs, char *buffer, size_t size) |
38f386574
|
896 897 898 |
{ bool trusted = capable(CAP_SYS_ADMIN); struct simple_xattr *xattr; |
786534b92
|
899 |
ssize_t remaining_size = size; |
0e9a7da51
|
900 |
int err = 0; |
786534b92
|
901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 |
#ifdef CONFIG_FS_POSIX_ACL if (inode->i_acl) { err = xattr_list_one(&buffer, &remaining_size, XATTR_NAME_POSIX_ACL_ACCESS); if (err) return err; } if (inode->i_default_acl) { err = xattr_list_one(&buffer, &remaining_size, XATTR_NAME_POSIX_ACL_DEFAULT); if (err) return err; } #endif |
38f386574
|
916 917 918 |
spin_lock(&xattrs->lock); list_for_each_entry(xattr, &xattrs->head, list) { |
38f386574
|
919 920 921 |
/* skip "trusted." attributes for unprivileged callers */ if (!trusted && xattr_is_trusted(xattr->name)) continue; |
786534b92
|
922 923 |
err = xattr_list_one(&buffer, &remaining_size, xattr->name); if (err) |
0e9a7da51
|
924 |
break; |
38f386574
|
925 926 |
} spin_unlock(&xattrs->lock); |
0e9a7da51
|
927 |
return err ? err : size - remaining_size; |
38f386574
|
928 |
} |
4895768b6
|
929 930 931 |
/* * Adds an extended attribute to the list */ |
38f386574
|
932 933 934 935 936 937 938 |
void simple_xattr_list_add(struct simple_xattrs *xattrs, struct simple_xattr *new_xattr) { spin_lock(&xattrs->lock); list_add(&new_xattr->list, &xattrs->head); spin_unlock(&xattrs->lock); } |