Dave Kleikamp | ac27a0e | 2006-10-11 01:20:50 -0700 | [diff] [blame^] | 1 | /* |
| 2 | * linux/fs/ext3/acl.c |
| 3 | * |
| 4 | * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de> |
| 5 | */ |
| 6 | |
| 7 | #include <linux/init.h> |
| 8 | #include <linux/sched.h> |
| 9 | #include <linux/slab.h> |
| 10 | #include <linux/capability.h> |
| 11 | #include <linux/fs.h> |
| 12 | #include <linux/ext3_jbd.h> |
| 13 | #include <linux/ext3_fs.h> |
| 14 | #include "xattr.h" |
| 15 | #include "acl.h" |
| 16 | |
| 17 | /* |
| 18 | * Convert from filesystem to in-memory representation. |
| 19 | */ |
| 20 | static struct posix_acl * |
| 21 | ext3_acl_from_disk(const void *value, size_t size) |
| 22 | { |
| 23 | const char *end = (char *)value + size; |
| 24 | int n, count; |
| 25 | struct posix_acl *acl; |
| 26 | |
| 27 | if (!value) |
| 28 | return NULL; |
| 29 | if (size < sizeof(ext3_acl_header)) |
| 30 | return ERR_PTR(-EINVAL); |
| 31 | if (((ext3_acl_header *)value)->a_version != |
| 32 | cpu_to_le32(EXT3_ACL_VERSION)) |
| 33 | return ERR_PTR(-EINVAL); |
| 34 | value = (char *)value + sizeof(ext3_acl_header); |
| 35 | count = ext3_acl_count(size); |
| 36 | if (count < 0) |
| 37 | return ERR_PTR(-EINVAL); |
| 38 | if (count == 0) |
| 39 | return NULL; |
| 40 | acl = posix_acl_alloc(count, GFP_KERNEL); |
| 41 | if (!acl) |
| 42 | return ERR_PTR(-ENOMEM); |
| 43 | for (n=0; n < count; n++) { |
| 44 | ext3_acl_entry *entry = |
| 45 | (ext3_acl_entry *)value; |
| 46 | if ((char *)value + sizeof(ext3_acl_entry_short) > end) |
| 47 | goto fail; |
| 48 | acl->a_entries[n].e_tag = le16_to_cpu(entry->e_tag); |
| 49 | acl->a_entries[n].e_perm = le16_to_cpu(entry->e_perm); |
| 50 | switch(acl->a_entries[n].e_tag) { |
| 51 | case ACL_USER_OBJ: |
| 52 | case ACL_GROUP_OBJ: |
| 53 | case ACL_MASK: |
| 54 | case ACL_OTHER: |
| 55 | value = (char *)value + |
| 56 | sizeof(ext3_acl_entry_short); |
| 57 | acl->a_entries[n].e_id = ACL_UNDEFINED_ID; |
| 58 | break; |
| 59 | |
| 60 | case ACL_USER: |
| 61 | case ACL_GROUP: |
| 62 | value = (char *)value + sizeof(ext3_acl_entry); |
| 63 | if ((char *)value > end) |
| 64 | goto fail; |
| 65 | acl->a_entries[n].e_id = |
| 66 | le32_to_cpu(entry->e_id); |
| 67 | break; |
| 68 | |
| 69 | default: |
| 70 | goto fail; |
| 71 | } |
| 72 | } |
| 73 | if (value != end) |
| 74 | goto fail; |
| 75 | return acl; |
| 76 | |
| 77 | fail: |
| 78 | posix_acl_release(acl); |
| 79 | return ERR_PTR(-EINVAL); |
| 80 | } |
| 81 | |
| 82 | /* |
| 83 | * Convert from in-memory to filesystem representation. |
| 84 | */ |
| 85 | static void * |
| 86 | ext3_acl_to_disk(const struct posix_acl *acl, size_t *size) |
| 87 | { |
| 88 | ext3_acl_header *ext_acl; |
| 89 | char *e; |
| 90 | size_t n; |
| 91 | |
| 92 | *size = ext3_acl_size(acl->a_count); |
| 93 | ext_acl = kmalloc(sizeof(ext3_acl_header) + acl->a_count * |
| 94 | sizeof(ext3_acl_entry), GFP_KERNEL); |
| 95 | if (!ext_acl) |
| 96 | return ERR_PTR(-ENOMEM); |
| 97 | ext_acl->a_version = cpu_to_le32(EXT3_ACL_VERSION); |
| 98 | e = (char *)ext_acl + sizeof(ext3_acl_header); |
| 99 | for (n=0; n < acl->a_count; n++) { |
| 100 | ext3_acl_entry *entry = (ext3_acl_entry *)e; |
| 101 | entry->e_tag = cpu_to_le16(acl->a_entries[n].e_tag); |
| 102 | entry->e_perm = cpu_to_le16(acl->a_entries[n].e_perm); |
| 103 | switch(acl->a_entries[n].e_tag) { |
| 104 | case ACL_USER: |
| 105 | case ACL_GROUP: |
| 106 | entry->e_id = |
| 107 | cpu_to_le32(acl->a_entries[n].e_id); |
| 108 | e += sizeof(ext3_acl_entry); |
| 109 | break; |
| 110 | |
| 111 | case ACL_USER_OBJ: |
| 112 | case ACL_GROUP_OBJ: |
| 113 | case ACL_MASK: |
| 114 | case ACL_OTHER: |
| 115 | e += sizeof(ext3_acl_entry_short); |
| 116 | break; |
| 117 | |
| 118 | default: |
| 119 | goto fail; |
| 120 | } |
| 121 | } |
| 122 | return (char *)ext_acl; |
| 123 | |
| 124 | fail: |
| 125 | kfree(ext_acl); |
| 126 | return ERR_PTR(-EINVAL); |
| 127 | } |
| 128 | |
| 129 | static inline struct posix_acl * |
| 130 | ext3_iget_acl(struct inode *inode, struct posix_acl **i_acl) |
| 131 | { |
| 132 | struct posix_acl *acl = EXT3_ACL_NOT_CACHED; |
| 133 | |
| 134 | spin_lock(&inode->i_lock); |
| 135 | if (*i_acl != EXT3_ACL_NOT_CACHED) |
| 136 | acl = posix_acl_dup(*i_acl); |
| 137 | spin_unlock(&inode->i_lock); |
| 138 | |
| 139 | return acl; |
| 140 | } |
| 141 | |
| 142 | static inline void |
| 143 | ext3_iset_acl(struct inode *inode, struct posix_acl **i_acl, |
| 144 | struct posix_acl *acl) |
| 145 | { |
| 146 | spin_lock(&inode->i_lock); |
| 147 | if (*i_acl != EXT3_ACL_NOT_CACHED) |
| 148 | posix_acl_release(*i_acl); |
| 149 | *i_acl = posix_acl_dup(acl); |
| 150 | spin_unlock(&inode->i_lock); |
| 151 | } |
| 152 | |
| 153 | /* |
| 154 | * Inode operation get_posix_acl(). |
| 155 | * |
| 156 | * inode->i_mutex: don't care |
| 157 | */ |
| 158 | static struct posix_acl * |
| 159 | ext3_get_acl(struct inode *inode, int type) |
| 160 | { |
| 161 | struct ext3_inode_info *ei = EXT3_I(inode); |
| 162 | int name_index; |
| 163 | char *value = NULL; |
| 164 | struct posix_acl *acl; |
| 165 | int retval; |
| 166 | |
| 167 | if (!test_opt(inode->i_sb, POSIX_ACL)) |
| 168 | return NULL; |
| 169 | |
| 170 | switch(type) { |
| 171 | case ACL_TYPE_ACCESS: |
| 172 | acl = ext3_iget_acl(inode, &ei->i_acl); |
| 173 | if (acl != EXT3_ACL_NOT_CACHED) |
| 174 | return acl; |
| 175 | name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS; |
| 176 | break; |
| 177 | |
| 178 | case ACL_TYPE_DEFAULT: |
| 179 | acl = ext3_iget_acl(inode, &ei->i_default_acl); |
| 180 | if (acl != EXT3_ACL_NOT_CACHED) |
| 181 | return acl; |
| 182 | name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT; |
| 183 | break; |
| 184 | |
| 185 | default: |
| 186 | return ERR_PTR(-EINVAL); |
| 187 | } |
| 188 | retval = ext3_xattr_get(inode, name_index, "", NULL, 0); |
| 189 | if (retval > 0) { |
| 190 | value = kmalloc(retval, GFP_KERNEL); |
| 191 | if (!value) |
| 192 | return ERR_PTR(-ENOMEM); |
| 193 | retval = ext3_xattr_get(inode, name_index, "", value, retval); |
| 194 | } |
| 195 | if (retval > 0) |
| 196 | acl = ext3_acl_from_disk(value, retval); |
| 197 | else if (retval == -ENODATA || retval == -ENOSYS) |
| 198 | acl = NULL; |
| 199 | else |
| 200 | acl = ERR_PTR(retval); |
| 201 | kfree(value); |
| 202 | |
| 203 | if (!IS_ERR(acl)) { |
| 204 | switch(type) { |
| 205 | case ACL_TYPE_ACCESS: |
| 206 | ext3_iset_acl(inode, &ei->i_acl, acl); |
| 207 | break; |
| 208 | |
| 209 | case ACL_TYPE_DEFAULT: |
| 210 | ext3_iset_acl(inode, &ei->i_default_acl, acl); |
| 211 | break; |
| 212 | } |
| 213 | } |
| 214 | return acl; |
| 215 | } |
| 216 | |
| 217 | /* |
| 218 | * Set the access or default ACL of an inode. |
| 219 | * |
| 220 | * inode->i_mutex: down unless called from ext3_new_inode |
| 221 | */ |
| 222 | static int |
| 223 | ext3_set_acl(handle_t *handle, struct inode *inode, int type, |
| 224 | struct posix_acl *acl) |
| 225 | { |
| 226 | struct ext3_inode_info *ei = EXT3_I(inode); |
| 227 | int name_index; |
| 228 | void *value = NULL; |
| 229 | size_t size = 0; |
| 230 | int error; |
| 231 | |
| 232 | if (S_ISLNK(inode->i_mode)) |
| 233 | return -EOPNOTSUPP; |
| 234 | |
| 235 | switch(type) { |
| 236 | case ACL_TYPE_ACCESS: |
| 237 | name_index = EXT3_XATTR_INDEX_POSIX_ACL_ACCESS; |
| 238 | if (acl) { |
| 239 | mode_t mode = inode->i_mode; |
| 240 | error = posix_acl_equiv_mode(acl, &mode); |
| 241 | if (error < 0) |
| 242 | return error; |
| 243 | else { |
| 244 | inode->i_mode = mode; |
| 245 | ext3_mark_inode_dirty(handle, inode); |
| 246 | if (error == 0) |
| 247 | acl = NULL; |
| 248 | } |
| 249 | } |
| 250 | break; |
| 251 | |
| 252 | case ACL_TYPE_DEFAULT: |
| 253 | name_index = EXT3_XATTR_INDEX_POSIX_ACL_DEFAULT; |
| 254 | if (!S_ISDIR(inode->i_mode)) |
| 255 | return acl ? -EACCES : 0; |
| 256 | break; |
| 257 | |
| 258 | default: |
| 259 | return -EINVAL; |
| 260 | } |
| 261 | if (acl) { |
| 262 | value = ext3_acl_to_disk(acl, &size); |
| 263 | if (IS_ERR(value)) |
| 264 | return (int)PTR_ERR(value); |
| 265 | } |
| 266 | |
| 267 | error = ext3_xattr_set_handle(handle, inode, name_index, "", |
| 268 | value, size, 0); |
| 269 | |
| 270 | kfree(value); |
| 271 | if (!error) { |
| 272 | switch(type) { |
| 273 | case ACL_TYPE_ACCESS: |
| 274 | ext3_iset_acl(inode, &ei->i_acl, acl); |
| 275 | break; |
| 276 | |
| 277 | case ACL_TYPE_DEFAULT: |
| 278 | ext3_iset_acl(inode, &ei->i_default_acl, acl); |
| 279 | break; |
| 280 | } |
| 281 | } |
| 282 | return error; |
| 283 | } |
| 284 | |
| 285 | static int |
| 286 | ext3_check_acl(struct inode *inode, int mask) |
| 287 | { |
| 288 | struct posix_acl *acl = ext3_get_acl(inode, ACL_TYPE_ACCESS); |
| 289 | |
| 290 | if (IS_ERR(acl)) |
| 291 | return PTR_ERR(acl); |
| 292 | if (acl) { |
| 293 | int error = posix_acl_permission(inode, acl, mask); |
| 294 | posix_acl_release(acl); |
| 295 | return error; |
| 296 | } |
| 297 | |
| 298 | return -EAGAIN; |
| 299 | } |
| 300 | |
| 301 | int |
| 302 | ext3_permission(struct inode *inode, int mask, struct nameidata *nd) |
| 303 | { |
| 304 | return generic_permission(inode, mask, ext3_check_acl); |
| 305 | } |
| 306 | |
| 307 | /* |
| 308 | * Initialize the ACLs of a new inode. Called from ext3_new_inode. |
| 309 | * |
| 310 | * dir->i_mutex: down |
| 311 | * inode->i_mutex: up (access to inode is still exclusive) |
| 312 | */ |
| 313 | int |
| 314 | ext3_init_acl(handle_t *handle, struct inode *inode, struct inode *dir) |
| 315 | { |
| 316 | struct posix_acl *acl = NULL; |
| 317 | int error = 0; |
| 318 | |
| 319 | if (!S_ISLNK(inode->i_mode)) { |
| 320 | if (test_opt(dir->i_sb, POSIX_ACL)) { |
| 321 | acl = ext3_get_acl(dir, ACL_TYPE_DEFAULT); |
| 322 | if (IS_ERR(acl)) |
| 323 | return PTR_ERR(acl); |
| 324 | } |
| 325 | if (!acl) |
| 326 | inode->i_mode &= ~current->fs->umask; |
| 327 | } |
| 328 | if (test_opt(inode->i_sb, POSIX_ACL) && acl) { |
| 329 | struct posix_acl *clone; |
| 330 | mode_t mode; |
| 331 | |
| 332 | if (S_ISDIR(inode->i_mode)) { |
| 333 | error = ext3_set_acl(handle, inode, |
| 334 | ACL_TYPE_DEFAULT, acl); |
| 335 | if (error) |
| 336 | goto cleanup; |
| 337 | } |
| 338 | clone = posix_acl_clone(acl, GFP_KERNEL); |
| 339 | error = -ENOMEM; |
| 340 | if (!clone) |
| 341 | goto cleanup; |
| 342 | |
| 343 | mode = inode->i_mode; |
| 344 | error = posix_acl_create_masq(clone, &mode); |
| 345 | if (error >= 0) { |
| 346 | inode->i_mode = mode; |
| 347 | if (error > 0) { |
| 348 | /* This is an extended ACL */ |
| 349 | error = ext3_set_acl(handle, inode, |
| 350 | ACL_TYPE_ACCESS, clone); |
| 351 | } |
| 352 | } |
| 353 | posix_acl_release(clone); |
| 354 | } |
| 355 | cleanup: |
| 356 | posix_acl_release(acl); |
| 357 | return error; |
| 358 | } |
| 359 | |
| 360 | /* |
| 361 | * Does chmod for an inode that may have an Access Control List. The |
| 362 | * inode->i_mode field must be updated to the desired value by the caller |
| 363 | * before calling this function. |
| 364 | * Returns 0 on success, or a negative error number. |
| 365 | * |
| 366 | * We change the ACL rather than storing some ACL entries in the file |
| 367 | * mode permission bits (which would be more efficient), because that |
| 368 | * would break once additional permissions (like ACL_APPEND, ACL_DELETE |
| 369 | * for directories) are added. There are no more bits available in the |
| 370 | * file mode. |
| 371 | * |
| 372 | * inode->i_mutex: down |
| 373 | */ |
| 374 | int |
| 375 | ext3_acl_chmod(struct inode *inode) |
| 376 | { |
| 377 | struct posix_acl *acl, *clone; |
| 378 | int error; |
| 379 | |
| 380 | if (S_ISLNK(inode->i_mode)) |
| 381 | return -EOPNOTSUPP; |
| 382 | if (!test_opt(inode->i_sb, POSIX_ACL)) |
| 383 | return 0; |
| 384 | acl = ext3_get_acl(inode, ACL_TYPE_ACCESS); |
| 385 | if (IS_ERR(acl) || !acl) |
| 386 | return PTR_ERR(acl); |
| 387 | clone = posix_acl_clone(acl, GFP_KERNEL); |
| 388 | posix_acl_release(acl); |
| 389 | if (!clone) |
| 390 | return -ENOMEM; |
| 391 | error = posix_acl_chmod_masq(clone, inode->i_mode); |
| 392 | if (!error) { |
| 393 | handle_t *handle; |
| 394 | int retries = 0; |
| 395 | |
| 396 | retry: |
| 397 | handle = ext3_journal_start(inode, |
| 398 | EXT3_DATA_TRANS_BLOCKS(inode->i_sb)); |
| 399 | if (IS_ERR(handle)) { |
| 400 | error = PTR_ERR(handle); |
| 401 | ext3_std_error(inode->i_sb, error); |
| 402 | goto out; |
| 403 | } |
| 404 | error = ext3_set_acl(handle, inode, ACL_TYPE_ACCESS, clone); |
| 405 | ext3_journal_stop(handle); |
| 406 | if (error == -ENOSPC && |
| 407 | ext3_should_retry_alloc(inode->i_sb, &retries)) |
| 408 | goto retry; |
| 409 | } |
| 410 | out: |
| 411 | posix_acl_release(clone); |
| 412 | return error; |
| 413 | } |
| 414 | |
| 415 | /* |
| 416 | * Extended attribute handlers |
| 417 | */ |
| 418 | static size_t |
| 419 | ext3_xattr_list_acl_access(struct inode *inode, char *list, size_t list_len, |
| 420 | const char *name, size_t name_len) |
| 421 | { |
| 422 | const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS); |
| 423 | |
| 424 | if (!test_opt(inode->i_sb, POSIX_ACL)) |
| 425 | return 0; |
| 426 | if (list && size <= list_len) |
| 427 | memcpy(list, POSIX_ACL_XATTR_ACCESS, size); |
| 428 | return size; |
| 429 | } |
| 430 | |
| 431 | static size_t |
| 432 | ext3_xattr_list_acl_default(struct inode *inode, char *list, size_t list_len, |
| 433 | const char *name, size_t name_len) |
| 434 | { |
| 435 | const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT); |
| 436 | |
| 437 | if (!test_opt(inode->i_sb, POSIX_ACL)) |
| 438 | return 0; |
| 439 | if (list && size <= list_len) |
| 440 | memcpy(list, POSIX_ACL_XATTR_DEFAULT, size); |
| 441 | return size; |
| 442 | } |
| 443 | |
| 444 | static int |
| 445 | ext3_xattr_get_acl(struct inode *inode, int type, void *buffer, size_t size) |
| 446 | { |
| 447 | struct posix_acl *acl; |
| 448 | int error; |
| 449 | |
| 450 | if (!test_opt(inode->i_sb, POSIX_ACL)) |
| 451 | return -EOPNOTSUPP; |
| 452 | |
| 453 | acl = ext3_get_acl(inode, type); |
| 454 | if (IS_ERR(acl)) |
| 455 | return PTR_ERR(acl); |
| 456 | if (acl == NULL) |
| 457 | return -ENODATA; |
| 458 | error = posix_acl_to_xattr(acl, buffer, size); |
| 459 | posix_acl_release(acl); |
| 460 | |
| 461 | return error; |
| 462 | } |
| 463 | |
| 464 | static int |
| 465 | ext3_xattr_get_acl_access(struct inode *inode, const char *name, |
| 466 | void *buffer, size_t size) |
| 467 | { |
| 468 | if (strcmp(name, "") != 0) |
| 469 | return -EINVAL; |
| 470 | return ext3_xattr_get_acl(inode, ACL_TYPE_ACCESS, buffer, size); |
| 471 | } |
| 472 | |
| 473 | static int |
| 474 | ext3_xattr_get_acl_default(struct inode *inode, const char *name, |
| 475 | void *buffer, size_t size) |
| 476 | { |
| 477 | if (strcmp(name, "") != 0) |
| 478 | return -EINVAL; |
| 479 | return ext3_xattr_get_acl(inode, ACL_TYPE_DEFAULT, buffer, size); |
| 480 | } |
| 481 | |
| 482 | static int |
| 483 | ext3_xattr_set_acl(struct inode *inode, int type, const void *value, |
| 484 | size_t size) |
| 485 | { |
| 486 | handle_t *handle; |
| 487 | struct posix_acl *acl; |
| 488 | int error, retries = 0; |
| 489 | |
| 490 | if (!test_opt(inode->i_sb, POSIX_ACL)) |
| 491 | return -EOPNOTSUPP; |
| 492 | if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER)) |
| 493 | return -EPERM; |
| 494 | |
| 495 | if (value) { |
| 496 | acl = posix_acl_from_xattr(value, size); |
| 497 | if (IS_ERR(acl)) |
| 498 | return PTR_ERR(acl); |
| 499 | else if (acl) { |
| 500 | error = posix_acl_valid(acl); |
| 501 | if (error) |
| 502 | goto release_and_out; |
| 503 | } |
| 504 | } else |
| 505 | acl = NULL; |
| 506 | |
| 507 | retry: |
| 508 | handle = ext3_journal_start(inode, EXT3_DATA_TRANS_BLOCKS(inode->i_sb)); |
| 509 | if (IS_ERR(handle)) |
| 510 | return PTR_ERR(handle); |
| 511 | error = ext3_set_acl(handle, inode, type, acl); |
| 512 | ext3_journal_stop(handle); |
| 513 | if (error == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries)) |
| 514 | goto retry; |
| 515 | |
| 516 | release_and_out: |
| 517 | posix_acl_release(acl); |
| 518 | return error; |
| 519 | } |
| 520 | |
| 521 | static int |
| 522 | ext3_xattr_set_acl_access(struct inode *inode, const char *name, |
| 523 | const void *value, size_t size, int flags) |
| 524 | { |
| 525 | if (strcmp(name, "") != 0) |
| 526 | return -EINVAL; |
| 527 | return ext3_xattr_set_acl(inode, ACL_TYPE_ACCESS, value, size); |
| 528 | } |
| 529 | |
| 530 | static int |
| 531 | ext3_xattr_set_acl_default(struct inode *inode, const char *name, |
| 532 | const void *value, size_t size, int flags) |
| 533 | { |
| 534 | if (strcmp(name, "") != 0) |
| 535 | return -EINVAL; |
| 536 | return ext3_xattr_set_acl(inode, ACL_TYPE_DEFAULT, value, size); |
| 537 | } |
| 538 | |
| 539 | struct xattr_handler ext3_xattr_acl_access_handler = { |
| 540 | .prefix = POSIX_ACL_XATTR_ACCESS, |
| 541 | .list = ext3_xattr_list_acl_access, |
| 542 | .get = ext3_xattr_get_acl_access, |
| 543 | .set = ext3_xattr_set_acl_access, |
| 544 | }; |
| 545 | |
| 546 | struct xattr_handler ext3_xattr_acl_default_handler = { |
| 547 | .prefix = POSIX_ACL_XATTR_DEFAULT, |
| 548 | .list = ext3_xattr_list_acl_default, |
| 549 | .get = ext3_xattr_get_acl_default, |
| 550 | .set = ext3_xattr_set_acl_default, |
| 551 | }; |