| 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> |
| 12 | #include <linux/file.h> |
| 13 | #include <linux/xattr.h> |
| 14 | #include <linux/mount.h> |
| 15 | #include <linux/namei.h> |
| 16 | #include <linux/security.h> |
| 17 | #include <linux/syscalls.h> |
| 18 | #include <linux/module.h> |
| 19 | #include <linux/fsnotify.h> |
| 20 | #include <linux/audit.h> |
| 21 | #include <asm/uaccess.h> |
| 22 | |
| 23 | |
| 24 | /* |
| 25 | * Check permissions for extended attribute access. This is a bit complicated |
| 26 | * because different namespaces have very different rules. |
| 27 | */ |
| 28 | static int |
| 29 | xattr_permission(struct inode *inode, const char *name, int mask) |
| 30 | { |
| 31 | /* |
| 32 | * We can never set or remove an extended attribute on a read-only |
| 33 | * filesystem or on an immutable / append-only inode. |
| 34 | */ |
| 35 | if (mask & MAY_WRITE) { |
| 36 | if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) |
| 37 | return -EPERM; |
| 38 | } |
| 39 | |
| 40 | /* |
| 41 | * No restriction for security.* and system.* from the VFS. Decision |
| 42 | * on these is left to the underlying filesystem / security module. |
| 43 | */ |
| 44 | if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) || |
| 45 | !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) |
| 46 | return 0; |
| 47 | |
| 48 | /* |
| 49 | * The trusted.* namespace can only be accessed by a privileged user. |
| 50 | */ |
| 51 | if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN)) |
| 52 | return (capable(CAP_SYS_ADMIN) ? 0 : -EPERM); |
| 53 | |
| 54 | /* In user.* namespace, only regular files and directories can have |
| 55 | * extended attributes. For sticky directories, only the owner and |
| 56 | * privileged user can write attributes. |
| 57 | */ |
| 58 | if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) { |
| 59 | if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode)) |
| 60 | return -EPERM; |
| 61 | if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) && |
| 62 | (mask & MAY_WRITE) && !is_owner_or_cap(inode)) |
| 63 | return -EPERM; |
| 64 | } |
| 65 | |
| 66 | return inode_permission(inode, mask); |
| 67 | } |
| 68 | |
| 69 | /** |
| 70 | * __vfs_setxattr_noperm - perform setxattr operation without performing |
| 71 | * permission checks. |
| 72 | * |
| 73 | * @dentry - object to perform setxattr on |
| 74 | * @name - xattr name to set |
| 75 | * @value - value to set @name to |
| 76 | * @size - size of @value |
| 77 | * @flags - flags to pass into filesystem operations |
| 78 | * |
| 79 | * returns the result of the internal setxattr or setsecurity operations. |
| 80 | * |
| 81 | * This function requires the caller to lock the inode's i_mutex before it |
| 82 | * is executed. It also assumes that the caller will make the appropriate |
| 83 | * permission checks. |
| 84 | */ |
| 85 | int __vfs_setxattr_noperm(struct dentry *dentry, const char *name, |
| 86 | const void *value, size_t size, int flags) |
| 87 | { |
| 88 | struct inode *inode = dentry->d_inode; |
| 89 | int error = -EOPNOTSUPP; |
| 90 | |
| 91 | if (inode->i_op->setxattr) { |
| 92 | error = inode->i_op->setxattr(dentry, name, value, size, flags); |
| 93 | if (!error) { |
| 94 | fsnotify_xattr(dentry); |
| 95 | security_inode_post_setxattr(dentry, name, value, |
| 96 | size, flags); |
| 97 | } |
| 98 | } else if (!strncmp(name, XATTR_SECURITY_PREFIX, |
| 99 | XATTR_SECURITY_PREFIX_LEN)) { |
| 100 | const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; |
| 101 | error = security_inode_setsecurity(inode, suffix, value, |
| 102 | size, flags); |
| 103 | if (!error) |
| 104 | fsnotify_xattr(dentry); |
| 105 | } |
| 106 | |
| 107 | return error; |
| 108 | } |
| 109 | |
| 110 | |
| 111 | int |
| 112 | vfs_setxattr(struct dentry *dentry, const char *name, const void *value, |
| 113 | size_t size, int flags) |
| 114 | { |
| 115 | struct inode *inode = dentry->d_inode; |
| 116 | int error; |
| 117 | |
| 118 | error = xattr_permission(inode, name, MAY_WRITE); |
| 119 | if (error) |
| 120 | return error; |
| 121 | |
| 122 | mutex_lock(&inode->i_mutex); |
| 123 | error = security_inode_setxattr(dentry, name, value, size, flags); |
| 124 | if (error) |
| 125 | goto out; |
| 126 | |
| 127 | error = __vfs_setxattr_noperm(dentry, name, value, size, flags); |
| 128 | |
| 129 | out: |
| 130 | mutex_unlock(&inode->i_mutex); |
| 131 | return error; |
| 132 | } |
| 133 | EXPORT_SYMBOL_GPL(vfs_setxattr); |
| 134 | |
| 135 | ssize_t |
| 136 | xattr_getsecurity(struct inode *inode, const char *name, void *value, |
| 137 | size_t size) |
| 138 | { |
| 139 | void *buffer = NULL; |
| 140 | ssize_t len; |
| 141 | |
| 142 | if (!value || !size) { |
| 143 | len = security_inode_getsecurity(inode, name, &buffer, false); |
| 144 | goto out_noalloc; |
| 145 | } |
| 146 | |
| 147 | len = security_inode_getsecurity(inode, name, &buffer, true); |
| 148 | if (len < 0) |
| 149 | return len; |
| 150 | if (size < len) { |
| 151 | len = -ERANGE; |
| 152 | goto out; |
| 153 | } |
| 154 | memcpy(value, buffer, len); |
| 155 | out: |
| 156 | security_release_secctx(buffer, len); |
| 157 | out_noalloc: |
| 158 | return len; |
| 159 | } |
| 160 | EXPORT_SYMBOL_GPL(xattr_getsecurity); |
| 161 | |
| 162 | ssize_t |
| 163 | vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size) |
| 164 | { |
| 165 | struct inode *inode = dentry->d_inode; |
| 166 | int error; |
| 167 | |
| 168 | error = xattr_permission(inode, name, MAY_READ); |
| 169 | if (error) |
| 170 | return error; |
| 171 | |
| 172 | error = security_inode_getxattr(dentry, name); |
| 173 | if (error) |
| 174 | return error; |
| 175 | |
| 176 | if (!strncmp(name, XATTR_SECURITY_PREFIX, |
| 177 | XATTR_SECURITY_PREFIX_LEN)) { |
| 178 | const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; |
| 179 | int ret = xattr_getsecurity(inode, suffix, value, size); |
| 180 | /* |
| 181 | * Only overwrite the return value if a security module |
| 182 | * is actually active. |
| 183 | */ |
| 184 | if (ret == -EOPNOTSUPP) |
| 185 | goto nolsm; |
| 186 | return ret; |
| 187 | } |
| 188 | nolsm: |
| 189 | if (inode->i_op->getxattr) |
| 190 | error = inode->i_op->getxattr(dentry, name, value, size); |
| 191 | else |
| 192 | error = -EOPNOTSUPP; |
| 193 | |
| 194 | return error; |
| 195 | } |
| 196 | EXPORT_SYMBOL_GPL(vfs_getxattr); |
| 197 | |
| 198 | ssize_t |
| 199 | vfs_listxattr(struct dentry *d, char *list, size_t size) |
| 200 | { |
| 201 | ssize_t error; |
| 202 | |
| 203 | error = security_inode_listxattr(d); |
| 204 | if (error) |
| 205 | return error; |
| 206 | error = -EOPNOTSUPP; |
| 207 | if (d->d_inode->i_op->listxattr) { |
| 208 | error = d->d_inode->i_op->listxattr(d, list, size); |
| 209 | } else { |
| 210 | error = security_inode_listsecurity(d->d_inode, list, size); |
| 211 | if (size && error > size) |
| 212 | error = -ERANGE; |
| 213 | } |
| 214 | return error; |
| 215 | } |
| 216 | EXPORT_SYMBOL_GPL(vfs_listxattr); |
| 217 | |
| 218 | int |
| 219 | vfs_removexattr(struct dentry *dentry, const char *name) |
| 220 | { |
| 221 | struct inode *inode = dentry->d_inode; |
| 222 | int error; |
| 223 | |
| 224 | if (!inode->i_op->removexattr) |
| 225 | return -EOPNOTSUPP; |
| 226 | |
| 227 | error = xattr_permission(inode, name, MAY_WRITE); |
| 228 | if (error) |
| 229 | return error; |
| 230 | |
| 231 | error = security_inode_removexattr(dentry, name); |
| 232 | if (error) |
| 233 | return error; |
| 234 | |
| 235 | mutex_lock(&inode->i_mutex); |
| 236 | error = inode->i_op->removexattr(dentry, name); |
| 237 | mutex_unlock(&inode->i_mutex); |
| 238 | |
| 239 | if (!error) |
| 240 | fsnotify_xattr(dentry); |
| 241 | return error; |
| 242 | } |
| 243 | EXPORT_SYMBOL_GPL(vfs_removexattr); |
| 244 | |
| 245 | |
| 246 | /* |
| 247 | * Extended attribute SET operations |
| 248 | */ |
| 249 | static long |
| 250 | setxattr(struct dentry *d, const char __user *name, const void __user *value, |
| 251 | size_t size, int flags) |
| 252 | { |
| 253 | int error; |
| 254 | void *kvalue = NULL; |
| 255 | char kname[XATTR_NAME_MAX + 1]; |
| 256 | |
| 257 | if (flags & ~(XATTR_CREATE|XATTR_REPLACE)) |
| 258 | return -EINVAL; |
| 259 | |
| 260 | error = strncpy_from_user(kname, name, sizeof(kname)); |
| 261 | if (error == 0 || error == sizeof(kname)) |
| 262 | error = -ERANGE; |
| 263 | if (error < 0) |
| 264 | return error; |
| 265 | |
| 266 | if (size) { |
| 267 | if (size > XATTR_SIZE_MAX) |
| 268 | return -E2BIG; |
| 269 | kvalue = memdup_user(value, size); |
| 270 | if (IS_ERR(kvalue)) |
| 271 | return PTR_ERR(kvalue); |
| 272 | } |
| 273 | |
| 274 | error = vfs_setxattr(d, kname, kvalue, size, flags); |
| 275 | kfree(kvalue); |
| 276 | return error; |
| 277 | } |
| 278 | |
| 279 | SYSCALL_DEFINE5(setxattr, const char __user *, pathname, |
| 280 | const char __user *, name, const void __user *, value, |
| 281 | size_t, size, int, flags) |
| 282 | { |
| 283 | struct path path; |
| 284 | int error; |
| 285 | |
| 286 | error = user_path(pathname, &path); |
| 287 | if (error) |
| 288 | return error; |
| 289 | error = mnt_want_write(path.mnt); |
| 290 | if (!error) { |
| 291 | error = setxattr(path.dentry, name, value, size, flags); |
| 292 | mnt_drop_write(path.mnt); |
| 293 | } |
| 294 | path_put(&path); |
| 295 | return error; |
| 296 | } |
| 297 | |
| 298 | SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname, |
| 299 | const char __user *, name, const void __user *, value, |
| 300 | size_t, size, int, flags) |
| 301 | { |
| 302 | struct path path; |
| 303 | int error; |
| 304 | |
| 305 | error = user_lpath(pathname, &path); |
| 306 | if (error) |
| 307 | return error; |
| 308 | error = mnt_want_write(path.mnt); |
| 309 | if (!error) { |
| 310 | error = setxattr(path.dentry, name, value, size, flags); |
| 311 | mnt_drop_write(path.mnt); |
| 312 | } |
| 313 | path_put(&path); |
| 314 | return error; |
| 315 | } |
| 316 | |
| 317 | SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name, |
| 318 | const void __user *,value, size_t, size, int, flags) |
| 319 | { |
| 320 | struct file *f; |
| 321 | struct dentry *dentry; |
| 322 | int error = -EBADF; |
| 323 | |
| 324 | f = fget(fd); |
| 325 | if (!f) |
| 326 | return error; |
| 327 | dentry = f->f_path.dentry; |
| 328 | audit_inode(NULL, dentry); |
| 329 | error = mnt_want_write_file(f); |
| 330 | if (!error) { |
| 331 | error = setxattr(dentry, name, value, size, flags); |
| 332 | mnt_drop_write(f->f_path.mnt); |
| 333 | } |
| 334 | fput(f); |
| 335 | return error; |
| 336 | } |
| 337 | |
| 338 | /* |
| 339 | * Extended attribute GET operations |
| 340 | */ |
| 341 | static ssize_t |
| 342 | getxattr(struct dentry *d, const char __user *name, void __user *value, |
| 343 | size_t size) |
| 344 | { |
| 345 | ssize_t error; |
| 346 | void *kvalue = NULL; |
| 347 | char kname[XATTR_NAME_MAX + 1]; |
| 348 | |
| 349 | error = strncpy_from_user(kname, name, sizeof(kname)); |
| 350 | if (error == 0 || error == sizeof(kname)) |
| 351 | error = -ERANGE; |
| 352 | if (error < 0) |
| 353 | return error; |
| 354 | |
| 355 | if (size) { |
| 356 | if (size > XATTR_SIZE_MAX) |
| 357 | size = XATTR_SIZE_MAX; |
| 358 | kvalue = kzalloc(size, GFP_KERNEL); |
| 359 | if (!kvalue) |
| 360 | return -ENOMEM; |
| 361 | } |
| 362 | |
| 363 | error = vfs_getxattr(d, kname, kvalue, size); |
| 364 | if (error > 0) { |
| 365 | if (size && copy_to_user(value, kvalue, error)) |
| 366 | error = -EFAULT; |
| 367 | } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) { |
| 368 | /* The file system tried to returned a value bigger |
| 369 | than XATTR_SIZE_MAX bytes. Not possible. */ |
| 370 | error = -E2BIG; |
| 371 | } |
| 372 | kfree(kvalue); |
| 373 | return error; |
| 374 | } |
| 375 | |
| 376 | SYSCALL_DEFINE4(getxattr, const char __user *, pathname, |
| 377 | const char __user *, name, void __user *, value, size_t, size) |
| 378 | { |
| 379 | struct path path; |
| 380 | ssize_t error; |
| 381 | |
| 382 | error = user_path(pathname, &path); |
| 383 | if (error) |
| 384 | return error; |
| 385 | error = getxattr(path.dentry, name, value, size); |
| 386 | path_put(&path); |
| 387 | return error; |
| 388 | } |
| 389 | |
| 390 | SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname, |
| 391 | const char __user *, name, void __user *, value, size_t, size) |
| 392 | { |
| 393 | struct path path; |
| 394 | ssize_t error; |
| 395 | |
| 396 | error = user_lpath(pathname, &path); |
| 397 | if (error) |
| 398 | return error; |
| 399 | error = getxattr(path.dentry, name, value, size); |
| 400 | path_put(&path); |
| 401 | return error; |
| 402 | } |
| 403 | |
| 404 | SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name, |
| 405 | void __user *, value, size_t, size) |
| 406 | { |
| 407 | struct file *f; |
| 408 | ssize_t error = -EBADF; |
| 409 | |
| 410 | f = fget(fd); |
| 411 | if (!f) |
| 412 | return error; |
| 413 | audit_inode(NULL, f->f_path.dentry); |
| 414 | error = getxattr(f->f_path.dentry, name, value, size); |
| 415 | fput(f); |
| 416 | return error; |
| 417 | } |
| 418 | |
| 419 | /* |
| 420 | * Extended attribute LIST operations |
| 421 | */ |
| 422 | static ssize_t |
| 423 | listxattr(struct dentry *d, char __user *list, size_t size) |
| 424 | { |
| 425 | ssize_t error; |
| 426 | char *klist = NULL; |
| 427 | |
| 428 | if (size) { |
| 429 | if (size > XATTR_LIST_MAX) |
| 430 | size = XATTR_LIST_MAX; |
| 431 | klist = kmalloc(size, GFP_KERNEL); |
| 432 | if (!klist) |
| 433 | return -ENOMEM; |
| 434 | } |
| 435 | |
| 436 | error = vfs_listxattr(d, klist, size); |
| 437 | if (error > 0) { |
| 438 | if (size && copy_to_user(list, klist, error)) |
| 439 | error = -EFAULT; |
| 440 | } else if (error == -ERANGE && size >= XATTR_LIST_MAX) { |
| 441 | /* The file system tried to returned a list bigger |
| 442 | than XATTR_LIST_MAX bytes. Not possible. */ |
| 443 | error = -E2BIG; |
| 444 | } |
| 445 | kfree(klist); |
| 446 | return error; |
| 447 | } |
| 448 | |
| 449 | SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list, |
| 450 | size_t, size) |
| 451 | { |
| 452 | struct path path; |
| 453 | ssize_t error; |
| 454 | |
| 455 | error = user_path(pathname, &path); |
| 456 | if (error) |
| 457 | return error; |
| 458 | error = listxattr(path.dentry, list, size); |
| 459 | path_put(&path); |
| 460 | return error; |
| 461 | } |
| 462 | |
| 463 | SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list, |
| 464 | size_t, size) |
| 465 | { |
| 466 | struct path path; |
| 467 | ssize_t error; |
| 468 | |
| 469 | error = user_lpath(pathname, &path); |
| 470 | if (error) |
| 471 | return error; |
| 472 | error = listxattr(path.dentry, list, size); |
| 473 | path_put(&path); |
| 474 | return error; |
| 475 | } |
| 476 | |
| 477 | SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size) |
| 478 | { |
| 479 | struct file *f; |
| 480 | ssize_t error = -EBADF; |
| 481 | |
| 482 | f = fget(fd); |
| 483 | if (!f) |
| 484 | return error; |
| 485 | audit_inode(NULL, f->f_path.dentry); |
| 486 | error = listxattr(f->f_path.dentry, list, size); |
| 487 | fput(f); |
| 488 | return error; |
| 489 | } |
| 490 | |
| 491 | /* |
| 492 | * Extended attribute REMOVE operations |
| 493 | */ |
| 494 | static long |
| 495 | removexattr(struct dentry *d, const char __user *name) |
| 496 | { |
| 497 | int error; |
| 498 | char kname[XATTR_NAME_MAX + 1]; |
| 499 | |
| 500 | error = strncpy_from_user(kname, name, sizeof(kname)); |
| 501 | if (error == 0 || error == sizeof(kname)) |
| 502 | error = -ERANGE; |
| 503 | if (error < 0) |
| 504 | return error; |
| 505 | |
| 506 | return vfs_removexattr(d, kname); |
| 507 | } |
| 508 | |
| 509 | SYSCALL_DEFINE2(removexattr, const char __user *, pathname, |
| 510 | const char __user *, name) |
| 511 | { |
| 512 | struct path path; |
| 513 | int error; |
| 514 | |
| 515 | error = user_path(pathname, &path); |
| 516 | if (error) |
| 517 | return error; |
| 518 | error = mnt_want_write(path.mnt); |
| 519 | if (!error) { |
| 520 | error = removexattr(path.dentry, name); |
| 521 | mnt_drop_write(path.mnt); |
| 522 | } |
| 523 | path_put(&path); |
| 524 | return error; |
| 525 | } |
| 526 | |
| 527 | SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname, |
| 528 | const char __user *, name) |
| 529 | { |
| 530 | struct path path; |
| 531 | int error; |
| 532 | |
| 533 | error = user_lpath(pathname, &path); |
| 534 | if (error) |
| 535 | return error; |
| 536 | error = mnt_want_write(path.mnt); |
| 537 | if (!error) { |
| 538 | error = removexattr(path.dentry, name); |
| 539 | mnt_drop_write(path.mnt); |
| 540 | } |
| 541 | path_put(&path); |
| 542 | return error; |
| 543 | } |
| 544 | |
| 545 | SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name) |
| 546 | { |
| 547 | struct file *f; |
| 548 | struct dentry *dentry; |
| 549 | int error = -EBADF; |
| 550 | |
| 551 | f = fget(fd); |
| 552 | if (!f) |
| 553 | return error; |
| 554 | dentry = f->f_path.dentry; |
| 555 | audit_inode(NULL, dentry); |
| 556 | error = mnt_want_write_file(f); |
| 557 | if (!error) { |
| 558 | error = removexattr(dentry, name); |
| 559 | mnt_drop_write(f->f_path.mnt); |
| 560 | } |
| 561 | fput(f); |
| 562 | return error; |
| 563 | } |
| 564 | |
| 565 | |
| 566 | static const char * |
| 567 | strcmp_prefix(const char *a, const char *a_prefix) |
| 568 | { |
| 569 | while (*a_prefix && *a == *a_prefix) { |
| 570 | a++; |
| 571 | a_prefix++; |
| 572 | } |
| 573 | return *a_prefix ? NULL : a; |
| 574 | } |
| 575 | |
| 576 | /* |
| 577 | * In order to implement different sets of xattr operations for each xattr |
| 578 | * prefix with the generic xattr API, a filesystem should create a |
| 579 | * null-terminated array of struct xattr_handler (one for each prefix) and |
| 580 | * hang a pointer to it off of the s_xattr field of the superblock. |
| 581 | * |
| 582 | * The generic_fooxattr() functions will use this list to dispatch xattr |
| 583 | * operations to the correct xattr_handler. |
| 584 | */ |
| 585 | #define for_each_xattr_handler(handlers, handler) \ |
| 586 | for ((handler) = *(handlers)++; \ |
| 587 | (handler) != NULL; \ |
| 588 | (handler) = *(handlers)++) |
| 589 | |
| 590 | /* |
| 591 | * Find the xattr_handler with the matching prefix. |
| 592 | */ |
| 593 | static struct xattr_handler * |
| 594 | xattr_resolve_name(struct xattr_handler **handlers, const char **name) |
| 595 | { |
| 596 | struct xattr_handler *handler; |
| 597 | |
| 598 | if (!*name) |
| 599 | return NULL; |
| 600 | |
| 601 | for_each_xattr_handler(handlers, handler) { |
| 602 | const char *n = strcmp_prefix(*name, handler->prefix); |
| 603 | if (n) { |
| 604 | *name = n; |
| 605 | break; |
| 606 | } |
| 607 | } |
| 608 | return handler; |
| 609 | } |
| 610 | |
| 611 | /* |
| 612 | * Find the handler for the prefix and dispatch its get() operation. |
| 613 | */ |
| 614 | ssize_t |
| 615 | generic_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size) |
| 616 | { |
| 617 | struct xattr_handler *handler; |
| 618 | |
| 619 | handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name); |
| 620 | if (!handler) |
| 621 | return -EOPNOTSUPP; |
| 622 | return handler->get(dentry, name, buffer, size, handler->flags); |
| 623 | } |
| 624 | |
| 625 | /* |
| 626 | * Combine the results of the list() operation from every xattr_handler in the |
| 627 | * list. |
| 628 | */ |
| 629 | ssize_t |
| 630 | generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) |
| 631 | { |
| 632 | struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr; |
| 633 | unsigned int size = 0; |
| 634 | |
| 635 | if (!buffer) { |
| 636 | for_each_xattr_handler(handlers, handler) { |
| 637 | size += handler->list(dentry, NULL, 0, NULL, 0, |
| 638 | handler->flags); |
| 639 | } |
| 640 | } else { |
| 641 | char *buf = buffer; |
| 642 | |
| 643 | for_each_xattr_handler(handlers, handler) { |
| 644 | size = handler->list(dentry, buf, buffer_size, |
| 645 | NULL, 0, handler->flags); |
| 646 | if (size > buffer_size) |
| 647 | return -ERANGE; |
| 648 | buf += size; |
| 649 | buffer_size -= size; |
| 650 | } |
| 651 | size = buf - buffer; |
| 652 | } |
| 653 | return size; |
| 654 | } |
| 655 | |
| 656 | /* |
| 657 | * Find the handler for the prefix and dispatch its set() operation. |
| 658 | */ |
| 659 | int |
| 660 | generic_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags) |
| 661 | { |
| 662 | struct xattr_handler *handler; |
| 663 | |
| 664 | if (size == 0) |
| 665 | value = ""; /* empty EA, do not remove */ |
| 666 | handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name); |
| 667 | if (!handler) |
| 668 | return -EOPNOTSUPP; |
| 669 | return handler->set(dentry, name, value, size, 0, handler->flags); |
| 670 | } |
| 671 | |
| 672 | /* |
| 673 | * Find the handler for the prefix and dispatch its set() operation to remove |
| 674 | * any associated extended attribute. |
| 675 | */ |
| 676 | int |
| 677 | generic_removexattr(struct dentry *dentry, const char *name) |
| 678 | { |
| 679 | struct xattr_handler *handler; |
| 680 | |
| 681 | handler = xattr_resolve_name(dentry->d_sb->s_xattr, &name); |
| 682 | if (!handler) |
| 683 | return -EOPNOTSUPP; |
| 684 | return handler->set(dentry, name, NULL, 0, |
| 685 | XATTR_REPLACE, handler->flags); |
| 686 | } |
| 687 | |
| 688 | EXPORT_SYMBOL(generic_getxattr); |
| 689 | EXPORT_SYMBOL(generic_listxattr); |
| 690 | EXPORT_SYMBOL(generic_setxattr); |
| 691 | EXPORT_SYMBOL(generic_removexattr); |