1 /* 2 * Copyright (C) 2002,2003 by Andreas Gruenbacher <a.gruenbacher@computer.org> 3 * 4 * Fixes from William Schumacher incorporated on 15 March 2001. 5 * (Reported by Charles Bertsch, <CBertsch@microtest.com>). 6 */ 7 8 /* 9 * This file contains generic functions for manipulating 10 * POSIX 1003.1e draft standard 17 ACLs. 11 */ 12 13 #include <linux/kernel.h> 14 #include <linux/slab.h> 15 #include <linux/atomic.h> 16 #include <linux/fs.h> 17 #include <linux/sched.h> 18 #include <linux/posix_acl.h> 19 #include <linux/posix_acl_xattr.h> 20 #include <linux/xattr.h> 21 #include <linux/export.h> 22 #include <linux/user_namespace.h> 23 24 static struct posix_acl **acl_by_type(struct inode *inode, int type) 25 { 26 switch (type) { 27 case ACL_TYPE_ACCESS: 28 return &inode->i_acl; 29 case ACL_TYPE_DEFAULT: 30 return &inode->i_default_acl; 31 default: 32 BUG(); 33 } 34 } 35 36 struct posix_acl *get_cached_acl(struct inode *inode, int type) 37 { 38 struct posix_acl **p = acl_by_type(inode, type); 39 struct posix_acl *acl; 40 41 for (;;) { 42 rcu_read_lock(); 43 acl = rcu_dereference(*p); 44 if (!acl || is_uncached_acl(acl) || 45 atomic_inc_not_zero(&acl->a_refcount)) 46 break; 47 rcu_read_unlock(); 48 cpu_relax(); 49 } 50 rcu_read_unlock(); 51 return acl; 52 } 53 EXPORT_SYMBOL(get_cached_acl); 54 55 struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type) 56 { 57 return rcu_dereference(*acl_by_type(inode, type)); 58 } 59 EXPORT_SYMBOL(get_cached_acl_rcu); 60 61 void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl) 62 { 63 struct posix_acl **p = acl_by_type(inode, type); 64 struct posix_acl *old; 65 66 old = xchg(p, posix_acl_dup(acl)); 67 if (!is_uncached_acl(old)) 68 posix_acl_release(old); 69 } 70 EXPORT_SYMBOL(set_cached_acl); 71 72 static void __forget_cached_acl(struct posix_acl **p) 73 { 74 struct posix_acl *old; 75 76 old = xchg(p, ACL_NOT_CACHED); 77 if (!is_uncached_acl(old)) 78 posix_acl_release(old); 79 } 80 81 void forget_cached_acl(struct inode *inode, int type) 82 { 83 __forget_cached_acl(acl_by_type(inode, type)); 84 } 85 EXPORT_SYMBOL(forget_cached_acl); 86 87 void forget_all_cached_acls(struct inode *inode) 88 { 89 __forget_cached_acl(&inode->i_acl); 90 __forget_cached_acl(&inode->i_default_acl); 91 } 92 EXPORT_SYMBOL(forget_all_cached_acls); 93 94 struct posix_acl *get_acl(struct inode *inode, int type) 95 { 96 void *sentinel; 97 struct posix_acl **p; 98 struct posix_acl *acl; 99 100 /* 101 * The sentinel is used to detect when another operation like 102 * set_cached_acl() or forget_cached_acl() races with get_acl(). 103 * It is guaranteed that is_uncached_acl(sentinel) is true. 104 */ 105 106 acl = get_cached_acl(inode, type); 107 if (!is_uncached_acl(acl)) 108 return acl; 109 110 if (!IS_POSIXACL(inode)) 111 return NULL; 112 113 sentinel = uncached_acl_sentinel(current); 114 p = acl_by_type(inode, type); 115 116 /* 117 * If the ACL isn't being read yet, set our sentinel. Otherwise, the 118 * current value of the ACL will not be ACL_NOT_CACHED and so our own 119 * sentinel will not be set; another task will update the cache. We 120 * could wait for that other task to complete its job, but it's easier 121 * to just call ->get_acl to fetch the ACL ourself. (This is going to 122 * be an unlikely race.) 123 */ 124 if (cmpxchg(p, ACL_NOT_CACHED, sentinel) != ACL_NOT_CACHED) 125 /* fall through */ ; 126 127 /* 128 * Normally, the ACL returned by ->get_acl will be cached. 129 * A filesystem can prevent that by calling 130 * forget_cached_acl(inode, type) in ->get_acl. 131 * 132 * If the filesystem doesn't have a get_acl() function at all, we'll 133 * just create the negative cache entry. 134 */ 135 if (!inode->i_op->get_acl) { 136 set_cached_acl(inode, type, NULL); 137 return NULL; 138 } 139 acl = inode->i_op->get_acl(inode, type); 140 141 if (IS_ERR(acl)) { 142 /* 143 * Remove our sentinel so that we don't block future attempts 144 * to cache the ACL. 145 */ 146 cmpxchg(p, sentinel, ACL_NOT_CACHED); 147 return acl; 148 } 149 150 /* 151 * Cache the result, but only if our sentinel is still in place. 152 */ 153 posix_acl_dup(acl); 154 if (unlikely(cmpxchg(p, sentinel, acl) != sentinel)) 155 posix_acl_release(acl); 156 return acl; 157 } 158 EXPORT_SYMBOL(get_acl); 159 160 /* 161 * Init a fresh posix_acl 162 */ 163 void 164 posix_acl_init(struct posix_acl *acl, int count) 165 { 166 atomic_set(&acl->a_refcount, 1); 167 acl->a_count = count; 168 } 169 EXPORT_SYMBOL(posix_acl_init); 170 171 /* 172 * Allocate a new ACL with the specified number of entries. 173 */ 174 struct posix_acl * 175 posix_acl_alloc(int count, gfp_t flags) 176 { 177 const size_t size = sizeof(struct posix_acl) + 178 count * sizeof(struct posix_acl_entry); 179 struct posix_acl *acl = kmalloc(size, flags); 180 if (acl) 181 posix_acl_init(acl, count); 182 return acl; 183 } 184 EXPORT_SYMBOL(posix_acl_alloc); 185 186 /* 187 * Clone an ACL. 188 */ 189 static struct posix_acl * 190 posix_acl_clone(const struct posix_acl *acl, gfp_t flags) 191 { 192 struct posix_acl *clone = NULL; 193 194 if (acl) { 195 int size = sizeof(struct posix_acl) + acl->a_count * 196 sizeof(struct posix_acl_entry); 197 clone = kmemdup(acl, size, flags); 198 if (clone) 199 atomic_set(&clone->a_refcount, 1); 200 } 201 return clone; 202 } 203 204 /* 205 * Check if an acl is valid. Returns 0 if it is, or -E... otherwise. 206 */ 207 int 208 posix_acl_valid(const struct posix_acl *acl) 209 { 210 const struct posix_acl_entry *pa, *pe; 211 int state = ACL_USER_OBJ; 212 int needs_mask = 0; 213 214 FOREACH_ACL_ENTRY(pa, acl, pe) { 215 if (pa->e_perm & ~(ACL_READ|ACL_WRITE|ACL_EXECUTE)) 216 return -EINVAL; 217 switch (pa->e_tag) { 218 case ACL_USER_OBJ: 219 if (state == ACL_USER_OBJ) { 220 state = ACL_USER; 221 break; 222 } 223 return -EINVAL; 224 225 case ACL_USER: 226 if (state != ACL_USER) 227 return -EINVAL; 228 if (!uid_valid(pa->e_uid)) 229 return -EINVAL; 230 needs_mask = 1; 231 break; 232 233 case ACL_GROUP_OBJ: 234 if (state == ACL_USER) { 235 state = ACL_GROUP; 236 break; 237 } 238 return -EINVAL; 239 240 case ACL_GROUP: 241 if (state != ACL_GROUP) 242 return -EINVAL; 243 if (!gid_valid(pa->e_gid)) 244 return -EINVAL; 245 needs_mask = 1; 246 break; 247 248 case ACL_MASK: 249 if (state != ACL_GROUP) 250 return -EINVAL; 251 state = ACL_OTHER; 252 break; 253 254 case ACL_OTHER: 255 if (state == ACL_OTHER || 256 (state == ACL_GROUP && !needs_mask)) { 257 state = 0; 258 break; 259 } 260 return -EINVAL; 261 262 default: 263 return -EINVAL; 264 } 265 } 266 if (state == 0) 267 return 0; 268 return -EINVAL; 269 } 270 EXPORT_SYMBOL(posix_acl_valid); 271 272 /* 273 * Returns 0 if the acl can be exactly represented in the traditional 274 * file mode permission bits, or else 1. Returns -E... on error. 275 */ 276 int 277 posix_acl_equiv_mode(const struct posix_acl *acl, umode_t *mode_p) 278 { 279 const struct posix_acl_entry *pa, *pe; 280 umode_t mode = 0; 281 int not_equiv = 0; 282 283 /* 284 * A null ACL can always be presented as mode bits. 285 */ 286 if (!acl) 287 return 0; 288 289 FOREACH_ACL_ENTRY(pa, acl, pe) { 290 switch (pa->e_tag) { 291 case ACL_USER_OBJ: 292 mode |= (pa->e_perm & S_IRWXO) << 6; 293 break; 294 case ACL_GROUP_OBJ: 295 mode |= (pa->e_perm & S_IRWXO) << 3; 296 break; 297 case ACL_OTHER: 298 mode |= pa->e_perm & S_IRWXO; 299 break; 300 case ACL_MASK: 301 mode = (mode & ~S_IRWXG) | 302 ((pa->e_perm & S_IRWXO) << 3); 303 not_equiv = 1; 304 break; 305 case ACL_USER: 306 case ACL_GROUP: 307 not_equiv = 1; 308 break; 309 default: 310 return -EINVAL; 311 } 312 } 313 if (mode_p) 314 *mode_p = (*mode_p & ~S_IRWXUGO) | mode; 315 return not_equiv; 316 } 317 EXPORT_SYMBOL(posix_acl_equiv_mode); 318 319 /* 320 * Create an ACL representing the file mode permission bits of an inode. 321 */ 322 struct posix_acl * 323 posix_acl_from_mode(umode_t mode, gfp_t flags) 324 { 325 struct posix_acl *acl = posix_acl_alloc(3, flags); 326 if (!acl) 327 return ERR_PTR(-ENOMEM); 328 329 acl->a_entries[0].e_tag = ACL_USER_OBJ; 330 acl->a_entries[0].e_perm = (mode & S_IRWXU) >> 6; 331 332 acl->a_entries[1].e_tag = ACL_GROUP_OBJ; 333 acl->a_entries[1].e_perm = (mode & S_IRWXG) >> 3; 334 335 acl->a_entries[2].e_tag = ACL_OTHER; 336 acl->a_entries[2].e_perm = (mode & S_IRWXO); 337 return acl; 338 } 339 EXPORT_SYMBOL(posix_acl_from_mode); 340 341 /* 342 * Return 0 if current is granted want access to the inode 343 * by the acl. Returns -E... otherwise. 344 */ 345 int 346 posix_acl_permission(struct inode *inode, const struct posix_acl *acl, int want) 347 { 348 const struct posix_acl_entry *pa, *pe, *mask_obj; 349 int found = 0; 350 351 want &= MAY_READ | MAY_WRITE | MAY_EXEC | MAY_NOT_BLOCK; 352 353 FOREACH_ACL_ENTRY(pa, acl, pe) { 354 switch(pa->e_tag) { 355 case ACL_USER_OBJ: 356 /* (May have been checked already) */ 357 if (uid_eq(inode->i_uid, current_fsuid())) 358 goto check_perm; 359 break; 360 case ACL_USER: 361 if (uid_eq(pa->e_uid, current_fsuid())) 362 goto mask; 363 break; 364 case ACL_GROUP_OBJ: 365 if (in_group_p(inode->i_gid)) { 366 found = 1; 367 if ((pa->e_perm & want) == want) 368 goto mask; 369 } 370 break; 371 case ACL_GROUP: 372 if (in_group_p(pa->e_gid)) { 373 found = 1; 374 if ((pa->e_perm & want) == want) 375 goto mask; 376 } 377 break; 378 case ACL_MASK: 379 break; 380 case ACL_OTHER: 381 if (found) 382 return -EACCES; 383 else 384 goto check_perm; 385 default: 386 return -EIO; 387 } 388 } 389 return -EIO; 390 391 mask: 392 for (mask_obj = pa+1; mask_obj != pe; mask_obj++) { 393 if (mask_obj->e_tag == ACL_MASK) { 394 if ((pa->e_perm & mask_obj->e_perm & want) == want) 395 return 0; 396 return -EACCES; 397 } 398 } 399 400 check_perm: 401 if ((pa->e_perm & want) == want) 402 return 0; 403 return -EACCES; 404 } 405 406 /* 407 * Modify acl when creating a new inode. The caller must ensure the acl is 408 * only referenced once. 409 * 410 * mode_p initially must contain the mode parameter to the open() / creat() 411 * system calls. All permissions that are not granted by the acl are removed. 412 * The permissions in the acl are changed to reflect the mode_p parameter. 413 */ 414 static int posix_acl_create_masq(struct posix_acl *acl, umode_t *mode_p) 415 { 416 struct posix_acl_entry *pa, *pe; 417 struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL; 418 umode_t mode = *mode_p; 419 int not_equiv = 0; 420 421 /* assert(atomic_read(acl->a_refcount) == 1); */ 422 423 FOREACH_ACL_ENTRY(pa, acl, pe) { 424 switch(pa->e_tag) { 425 case ACL_USER_OBJ: 426 pa->e_perm &= (mode >> 6) | ~S_IRWXO; 427 mode &= (pa->e_perm << 6) | ~S_IRWXU; 428 break; 429 430 case ACL_USER: 431 case ACL_GROUP: 432 not_equiv = 1; 433 break; 434 435 case ACL_GROUP_OBJ: 436 group_obj = pa; 437 break; 438 439 case ACL_OTHER: 440 pa->e_perm &= mode | ~S_IRWXO; 441 mode &= pa->e_perm | ~S_IRWXO; 442 break; 443 444 case ACL_MASK: 445 mask_obj = pa; 446 not_equiv = 1; 447 break; 448 449 default: 450 return -EIO; 451 } 452 } 453 454 if (mask_obj) { 455 mask_obj->e_perm &= (mode >> 3) | ~S_IRWXO; 456 mode &= (mask_obj->e_perm << 3) | ~S_IRWXG; 457 } else { 458 if (!group_obj) 459 return -EIO; 460 group_obj->e_perm &= (mode >> 3) | ~S_IRWXO; 461 mode &= (group_obj->e_perm << 3) | ~S_IRWXG; 462 } 463 464 *mode_p = (*mode_p & ~S_IRWXUGO) | mode; 465 return not_equiv; 466 } 467 468 /* 469 * Modify the ACL for the chmod syscall. 470 */ 471 static int __posix_acl_chmod_masq(struct posix_acl *acl, umode_t mode) 472 { 473 struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL; 474 struct posix_acl_entry *pa, *pe; 475 476 /* assert(atomic_read(acl->a_refcount) == 1); */ 477 478 FOREACH_ACL_ENTRY(pa, acl, pe) { 479 switch(pa->e_tag) { 480 case ACL_USER_OBJ: 481 pa->e_perm = (mode & S_IRWXU) >> 6; 482 break; 483 484 case ACL_USER: 485 case ACL_GROUP: 486 break; 487 488 case ACL_GROUP_OBJ: 489 group_obj = pa; 490 break; 491 492 case ACL_MASK: 493 mask_obj = pa; 494 break; 495 496 case ACL_OTHER: 497 pa->e_perm = (mode & S_IRWXO); 498 break; 499 500 default: 501 return -EIO; 502 } 503 } 504 505 if (mask_obj) { 506 mask_obj->e_perm = (mode & S_IRWXG) >> 3; 507 } else { 508 if (!group_obj) 509 return -EIO; 510 group_obj->e_perm = (mode & S_IRWXG) >> 3; 511 } 512 513 return 0; 514 } 515 516 int 517 __posix_acl_create(struct posix_acl **acl, gfp_t gfp, umode_t *mode_p) 518 { 519 struct posix_acl *clone = posix_acl_clone(*acl, gfp); 520 int err = -ENOMEM; 521 if (clone) { 522 err = posix_acl_create_masq(clone, mode_p); 523 if (err < 0) { 524 posix_acl_release(clone); 525 clone = NULL; 526 } 527 } 528 posix_acl_release(*acl); 529 *acl = clone; 530 return err; 531 } 532 EXPORT_SYMBOL(__posix_acl_create); 533 534 int 535 __posix_acl_chmod(struct posix_acl **acl, gfp_t gfp, umode_t mode) 536 { 537 struct posix_acl *clone = posix_acl_clone(*acl, gfp); 538 int err = -ENOMEM; 539 if (clone) { 540 err = __posix_acl_chmod_masq(clone, mode); 541 if (err) { 542 posix_acl_release(clone); 543 clone = NULL; 544 } 545 } 546 posix_acl_release(*acl); 547 *acl = clone; 548 return err; 549 } 550 EXPORT_SYMBOL(__posix_acl_chmod); 551 552 int 553 posix_acl_chmod(struct inode *inode, umode_t mode) 554 { 555 struct posix_acl *acl; 556 int ret = 0; 557 558 if (!IS_POSIXACL(inode)) 559 return 0; 560 if (!inode->i_op->set_acl) 561 return -EOPNOTSUPP; 562 563 acl = get_acl(inode, ACL_TYPE_ACCESS); 564 if (IS_ERR_OR_NULL(acl)) { 565 if (acl == ERR_PTR(-EOPNOTSUPP)) 566 return 0; 567 return PTR_ERR(acl); 568 } 569 570 ret = __posix_acl_chmod(&acl, GFP_KERNEL, mode); 571 if (ret) 572 return ret; 573 ret = inode->i_op->set_acl(inode, acl, ACL_TYPE_ACCESS); 574 posix_acl_release(acl); 575 return ret; 576 } 577 EXPORT_SYMBOL(posix_acl_chmod); 578 579 int 580 posix_acl_create(struct inode *dir, umode_t *mode, 581 struct posix_acl **default_acl, struct posix_acl **acl) 582 { 583 struct posix_acl *p; 584 struct posix_acl *clone; 585 int ret; 586 587 *acl = NULL; 588 *default_acl = NULL; 589 590 if (S_ISLNK(*mode) || !IS_POSIXACL(dir)) 591 return 0; 592 593 p = get_acl(dir, ACL_TYPE_DEFAULT); 594 if (!p || p == ERR_PTR(-EOPNOTSUPP)) { 595 *mode &= ~current_umask(); 596 return 0; 597 } 598 if (IS_ERR(p)) 599 return PTR_ERR(p); 600 601 clone = posix_acl_clone(p, GFP_NOFS); 602 if (!clone) 603 goto no_mem; 604 605 ret = posix_acl_create_masq(clone, mode); 606 if (ret < 0) 607 goto no_mem_clone; 608 609 if (ret == 0) 610 posix_acl_release(clone); 611 else 612 *acl = clone; 613 614 if (!S_ISDIR(*mode)) 615 posix_acl_release(p); 616 else 617 *default_acl = p; 618 619 return 0; 620 621 no_mem_clone: 622 posix_acl_release(clone); 623 no_mem: 624 posix_acl_release(p); 625 return -ENOMEM; 626 } 627 EXPORT_SYMBOL_GPL(posix_acl_create); 628 629 /* 630 * Fix up the uids and gids in posix acl extended attributes in place. 631 */ 632 static void posix_acl_fix_xattr_userns( 633 struct user_namespace *to, struct user_namespace *from, 634 void *value, size_t size) 635 { 636 posix_acl_xattr_header *header = (posix_acl_xattr_header *)value; 637 posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end; 638 int count; 639 kuid_t uid; 640 kgid_t gid; 641 642 if (!value) 643 return; 644 if (size < sizeof(posix_acl_xattr_header)) 645 return; 646 if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION)) 647 return; 648 649 count = posix_acl_xattr_count(size); 650 if (count < 0) 651 return; 652 if (count == 0) 653 return; 654 655 for (end = entry + count; entry != end; entry++) { 656 switch(le16_to_cpu(entry->e_tag)) { 657 case ACL_USER: 658 uid = make_kuid(from, le32_to_cpu(entry->e_id)); 659 entry->e_id = cpu_to_le32(from_kuid(to, uid)); 660 break; 661 case ACL_GROUP: 662 gid = make_kgid(from, le32_to_cpu(entry->e_id)); 663 entry->e_id = cpu_to_le32(from_kgid(to, gid)); 664 break; 665 default: 666 break; 667 } 668 } 669 } 670 671 void posix_acl_fix_xattr_from_user(void *value, size_t size) 672 { 673 struct user_namespace *user_ns = current_user_ns(); 674 if (user_ns == &init_user_ns) 675 return; 676 posix_acl_fix_xattr_userns(&init_user_ns, user_ns, value, size); 677 } 678 679 void posix_acl_fix_xattr_to_user(void *value, size_t size) 680 { 681 struct user_namespace *user_ns = current_user_ns(); 682 if (user_ns == &init_user_ns) 683 return; 684 posix_acl_fix_xattr_userns(user_ns, &init_user_ns, value, size); 685 } 686 687 /* 688 * Convert from extended attribute to in-memory representation. 689 */ 690 struct posix_acl * 691 posix_acl_from_xattr(struct user_namespace *user_ns, 692 const void *value, size_t size) 693 { 694 posix_acl_xattr_header *header = (posix_acl_xattr_header *)value; 695 posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end; 696 int count; 697 struct posix_acl *acl; 698 struct posix_acl_entry *acl_e; 699 700 if (!value) 701 return NULL; 702 if (size < sizeof(posix_acl_xattr_header)) 703 return ERR_PTR(-EINVAL); 704 if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION)) 705 return ERR_PTR(-EOPNOTSUPP); 706 707 count = posix_acl_xattr_count(size); 708 if (count < 0) 709 return ERR_PTR(-EINVAL); 710 if (count == 0) 711 return NULL; 712 713 acl = posix_acl_alloc(count, GFP_NOFS); 714 if (!acl) 715 return ERR_PTR(-ENOMEM); 716 acl_e = acl->a_entries; 717 718 for (end = entry + count; entry != end; acl_e++, entry++) { 719 acl_e->e_tag = le16_to_cpu(entry->e_tag); 720 acl_e->e_perm = le16_to_cpu(entry->e_perm); 721 722 switch(acl_e->e_tag) { 723 case ACL_USER_OBJ: 724 case ACL_GROUP_OBJ: 725 case ACL_MASK: 726 case ACL_OTHER: 727 break; 728 729 case ACL_USER: 730 acl_e->e_uid = 731 make_kuid(user_ns, 732 le32_to_cpu(entry->e_id)); 733 if (!uid_valid(acl_e->e_uid)) 734 goto fail; 735 break; 736 case ACL_GROUP: 737 acl_e->e_gid = 738 make_kgid(user_ns, 739 le32_to_cpu(entry->e_id)); 740 if (!gid_valid(acl_e->e_gid)) 741 goto fail; 742 break; 743 744 default: 745 goto fail; 746 } 747 } 748 return acl; 749 750 fail: 751 posix_acl_release(acl); 752 return ERR_PTR(-EINVAL); 753 } 754 EXPORT_SYMBOL (posix_acl_from_xattr); 755 756 /* 757 * Convert from in-memory to extended attribute representation. 758 */ 759 int 760 posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl, 761 void *buffer, size_t size) 762 { 763 posix_acl_xattr_header *ext_acl = (posix_acl_xattr_header *)buffer; 764 posix_acl_xattr_entry *ext_entry; 765 int real_size, n; 766 767 real_size = posix_acl_xattr_size(acl->a_count); 768 if (!buffer) 769 return real_size; 770 if (real_size > size) 771 return -ERANGE; 772 773 ext_entry = ext_acl->a_entries; 774 ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION); 775 776 for (n=0; n < acl->a_count; n++, ext_entry++) { 777 const struct posix_acl_entry *acl_e = &acl->a_entries[n]; 778 ext_entry->e_tag = cpu_to_le16(acl_e->e_tag); 779 ext_entry->e_perm = cpu_to_le16(acl_e->e_perm); 780 switch(acl_e->e_tag) { 781 case ACL_USER: 782 ext_entry->e_id = 783 cpu_to_le32(from_kuid(user_ns, acl_e->e_uid)); 784 break; 785 case ACL_GROUP: 786 ext_entry->e_id = 787 cpu_to_le32(from_kgid(user_ns, acl_e->e_gid)); 788 break; 789 default: 790 ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID); 791 break; 792 } 793 } 794 return real_size; 795 } 796 EXPORT_SYMBOL (posix_acl_to_xattr); 797 798 static int 799 posix_acl_xattr_get(const struct xattr_handler *handler, 800 struct dentry *dentry, const char *name, 801 void *value, size_t size) 802 { 803 struct posix_acl *acl; 804 int error; 805 806 if (!IS_POSIXACL(d_backing_inode(dentry))) 807 return -EOPNOTSUPP; 808 if (d_is_symlink(dentry)) 809 return -EOPNOTSUPP; 810 811 acl = get_acl(d_backing_inode(dentry), handler->flags); 812 if (IS_ERR(acl)) 813 return PTR_ERR(acl); 814 if (acl == NULL) 815 return -ENODATA; 816 817 error = posix_acl_to_xattr(&init_user_ns, acl, value, size); 818 posix_acl_release(acl); 819 820 return error; 821 } 822 823 static int 824 posix_acl_xattr_set(const struct xattr_handler *handler, 825 struct dentry *dentry, const char *name, 826 const void *value, size_t size, int flags) 827 { 828 struct inode *inode = d_backing_inode(dentry); 829 struct posix_acl *acl = NULL; 830 int ret; 831 832 if (!IS_POSIXACL(inode)) 833 return -EOPNOTSUPP; 834 if (!inode->i_op->set_acl) 835 return -EOPNOTSUPP; 836 837 if (handler->flags == ACL_TYPE_DEFAULT && !S_ISDIR(inode->i_mode)) 838 return value ? -EACCES : 0; 839 if (!inode_owner_or_capable(inode)) 840 return -EPERM; 841 842 if (value) { 843 acl = posix_acl_from_xattr(&init_user_ns, value, size); 844 if (IS_ERR(acl)) 845 return PTR_ERR(acl); 846 847 if (acl) { 848 ret = posix_acl_valid(acl); 849 if (ret) 850 goto out; 851 } 852 } 853 854 ret = inode->i_op->set_acl(inode, acl, handler->flags); 855 out: 856 posix_acl_release(acl); 857 return ret; 858 } 859 860 static bool 861 posix_acl_xattr_list(struct dentry *dentry) 862 { 863 return IS_POSIXACL(d_backing_inode(dentry)); 864 } 865 866 const struct xattr_handler posix_acl_access_xattr_handler = { 867 .name = XATTR_NAME_POSIX_ACL_ACCESS, 868 .flags = ACL_TYPE_ACCESS, 869 .list = posix_acl_xattr_list, 870 .get = posix_acl_xattr_get, 871 .set = posix_acl_xattr_set, 872 }; 873 EXPORT_SYMBOL_GPL(posix_acl_access_xattr_handler); 874 875 const struct xattr_handler posix_acl_default_xattr_handler = { 876 .name = XATTR_NAME_POSIX_ACL_DEFAULT, 877 .flags = ACL_TYPE_DEFAULT, 878 .list = posix_acl_xattr_list, 879 .get = posix_acl_xattr_get, 880 .set = posix_acl_xattr_set, 881 }; 882 EXPORT_SYMBOL_GPL(posix_acl_default_xattr_handler); 883 884 int simple_set_acl(struct inode *inode, struct posix_acl *acl, int type) 885 { 886 int error; 887 888 if (type == ACL_TYPE_ACCESS) { 889 error = posix_acl_equiv_mode(acl, &inode->i_mode); 890 if (error < 0) 891 return 0; 892 if (error == 0) 893 acl = NULL; 894 } 895 896 inode->i_ctime = CURRENT_TIME; 897 set_cached_acl(inode, type, acl); 898 return 0; 899 } 900 901 int simple_acl_create(struct inode *dir, struct inode *inode) 902 { 903 struct posix_acl *default_acl, *acl; 904 int error; 905 906 error = posix_acl_create(dir, &inode->i_mode, &default_acl, &acl); 907 if (error) 908 return error; 909 910 set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl); 911 set_cached_acl(inode, ACL_TYPE_ACCESS, acl); 912 913 if (default_acl) 914 posix_acl_release(default_acl); 915 if (acl) 916 posix_acl_release(acl); 917 return 0; 918 } 919