1 /* 2 * Implementation of the access vector table type. 3 * 4 * Author : Stephen Smalley, <sds@tycho.nsa.gov> 5 */ 6 7 /* Updated: Frank Mayer <mayerf@tresys.com> and Karl MacMillan <kmacmillan@tresys.com> 8 * 9 * Added conditional policy language extensions 10 * 11 * Copyright (C) 2003 Tresys Technology, LLC 12 * This program is free software; you can redistribute it and/or modify 13 * it under the terms of the GNU General Public License as published by 14 * the Free Software Foundation, version 2. 15 * 16 * Updated: Yuichi Nakamura <ynakam@hitachisoft.jp> 17 * Tuned number of hash slots for avtab to reduce memory usage 18 */ 19 20 #include <linux/kernel.h> 21 #include <linux/slab.h> 22 #include <linux/errno.h> 23 #include "avtab.h" 24 #include "policydb.h" 25 26 static struct kmem_cache *avtab_node_cachep __ro_after_init; 27 static struct kmem_cache *avtab_xperms_cachep __ro_after_init; 28 29 /* Based on MurmurHash3, written by Austin Appleby and placed in the 30 * public domain. 31 */ 32 static inline int avtab_hash(const struct avtab_key *keyp, u32 mask) 33 { 34 static const u32 c1 = 0xcc9e2d51; 35 static const u32 c2 = 0x1b873593; 36 static const u32 r1 = 15; 37 static const u32 r2 = 13; 38 static const u32 m = 5; 39 static const u32 n = 0xe6546b64; 40 41 u32 hash = 0; 42 43 #define mix(input) do { \ 44 u32 v = input; \ 45 v *= c1; \ 46 v = (v << r1) | (v >> (32 - r1)); \ 47 v *= c2; \ 48 hash ^= v; \ 49 hash = (hash << r2) | (hash >> (32 - r2)); \ 50 hash = hash * m + n; \ 51 } while (0) 52 53 mix(keyp->target_class); 54 mix(keyp->target_type); 55 mix(keyp->source_type); 56 57 #undef mix 58 59 hash ^= hash >> 16; 60 hash *= 0x85ebca6b; 61 hash ^= hash >> 13; 62 hash *= 0xc2b2ae35; 63 hash ^= hash >> 16; 64 65 return hash & mask; 66 } 67 68 static struct avtab_node* 69 avtab_insert_node(struct avtab *h, int hvalue, 70 struct avtab_node *prev, 71 const struct avtab_key *key, const struct avtab_datum *datum) 72 { 73 struct avtab_node *newnode; 74 struct avtab_extended_perms *xperms; 75 newnode = kmem_cache_zalloc(avtab_node_cachep, GFP_KERNEL); 76 if (newnode == NULL) 77 return NULL; 78 newnode->key = *key; 79 80 if (key->specified & AVTAB_XPERMS) { 81 xperms = kmem_cache_zalloc(avtab_xperms_cachep, GFP_KERNEL); 82 if (xperms == NULL) { 83 kmem_cache_free(avtab_node_cachep, newnode); 84 return NULL; 85 } 86 *xperms = *(datum->u.xperms); 87 newnode->datum.u.xperms = xperms; 88 } else { 89 newnode->datum.u.data = datum->u.data; 90 } 91 92 if (prev) { 93 newnode->next = prev->next; 94 prev->next = newnode; 95 } else { 96 struct avtab_node **n = &h->htable[hvalue]; 97 98 newnode->next = *n; 99 *n = newnode; 100 } 101 102 h->nel++; 103 return newnode; 104 } 105 106 static int avtab_insert(struct avtab *h, const struct avtab_key *key, 107 const struct avtab_datum *datum) 108 { 109 int hvalue; 110 struct avtab_node *prev, *cur, *newnode; 111 u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD); 112 113 if (!h || !h->nslot) 114 return -EINVAL; 115 116 hvalue = avtab_hash(key, h->mask); 117 for (prev = NULL, cur = h->htable[hvalue]; 118 cur; 119 prev = cur, cur = cur->next) { 120 if (key->source_type == cur->key.source_type && 121 key->target_type == cur->key.target_type && 122 key->target_class == cur->key.target_class && 123 (specified & cur->key.specified)) { 124 /* extended perms may not be unique */ 125 if (specified & AVTAB_XPERMS) 126 break; 127 return -EEXIST; 128 } 129 if (key->source_type < cur->key.source_type) 130 break; 131 if (key->source_type == cur->key.source_type && 132 key->target_type < cur->key.target_type) 133 break; 134 if (key->source_type == cur->key.source_type && 135 key->target_type == cur->key.target_type && 136 key->target_class < cur->key.target_class) 137 break; 138 } 139 140 newnode = avtab_insert_node(h, hvalue, prev, key, datum); 141 if (!newnode) 142 return -ENOMEM; 143 144 return 0; 145 } 146 147 /* Unlike avtab_insert(), this function allow multiple insertions of the same 148 * key/specified mask into the table, as needed by the conditional avtab. 149 * It also returns a pointer to the node inserted. 150 */ 151 struct avtab_node *avtab_insert_nonunique(struct avtab *h, 152 const struct avtab_key *key, 153 const struct avtab_datum *datum) 154 { 155 int hvalue; 156 struct avtab_node *prev, *cur; 157 u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD); 158 159 if (!h || !h->nslot) 160 return NULL; 161 hvalue = avtab_hash(key, h->mask); 162 for (prev = NULL, cur = h->htable[hvalue]; 163 cur; 164 prev = cur, cur = cur->next) { 165 if (key->source_type == cur->key.source_type && 166 key->target_type == cur->key.target_type && 167 key->target_class == cur->key.target_class && 168 (specified & cur->key.specified)) 169 break; 170 if (key->source_type < cur->key.source_type) 171 break; 172 if (key->source_type == cur->key.source_type && 173 key->target_type < cur->key.target_type) 174 break; 175 if (key->source_type == cur->key.source_type && 176 key->target_type == cur->key.target_type && 177 key->target_class < cur->key.target_class) 178 break; 179 } 180 return avtab_insert_node(h, hvalue, prev, key, datum); 181 } 182 183 struct avtab_datum *avtab_search(struct avtab *h, const struct avtab_key *key) 184 { 185 int hvalue; 186 struct avtab_node *cur; 187 u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD); 188 189 if (!h || !h->nslot) 190 return NULL; 191 192 hvalue = avtab_hash(key, h->mask); 193 for (cur = h->htable[hvalue]; cur; 194 cur = cur->next) { 195 if (key->source_type == cur->key.source_type && 196 key->target_type == cur->key.target_type && 197 key->target_class == cur->key.target_class && 198 (specified & cur->key.specified)) 199 return &cur->datum; 200 201 if (key->source_type < cur->key.source_type) 202 break; 203 if (key->source_type == cur->key.source_type && 204 key->target_type < cur->key.target_type) 205 break; 206 if (key->source_type == cur->key.source_type && 207 key->target_type == cur->key.target_type && 208 key->target_class < cur->key.target_class) 209 break; 210 } 211 212 return NULL; 213 } 214 215 /* This search function returns a node pointer, and can be used in 216 * conjunction with avtab_search_next_node() 217 */ 218 struct avtab_node *avtab_search_node(struct avtab *h, 219 const struct avtab_key *key) 220 { 221 int hvalue; 222 struct avtab_node *cur; 223 u16 specified = key->specified & ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD); 224 225 if (!h || !h->nslot) 226 return NULL; 227 228 hvalue = avtab_hash(key, h->mask); 229 for (cur = h->htable[hvalue]; cur; 230 cur = cur->next) { 231 if (key->source_type == cur->key.source_type && 232 key->target_type == cur->key.target_type && 233 key->target_class == cur->key.target_class && 234 (specified & cur->key.specified)) 235 return cur; 236 237 if (key->source_type < cur->key.source_type) 238 break; 239 if (key->source_type == cur->key.source_type && 240 key->target_type < cur->key.target_type) 241 break; 242 if (key->source_type == cur->key.source_type && 243 key->target_type == cur->key.target_type && 244 key->target_class < cur->key.target_class) 245 break; 246 } 247 return NULL; 248 } 249 250 struct avtab_node* 251 avtab_search_node_next(struct avtab_node *node, int specified) 252 { 253 struct avtab_node *cur; 254 255 if (!node) 256 return NULL; 257 258 specified &= ~(AVTAB_ENABLED|AVTAB_ENABLED_OLD); 259 for (cur = node->next; cur; cur = cur->next) { 260 if (node->key.source_type == cur->key.source_type && 261 node->key.target_type == cur->key.target_type && 262 node->key.target_class == cur->key.target_class && 263 (specified & cur->key.specified)) 264 return cur; 265 266 if (node->key.source_type < cur->key.source_type) 267 break; 268 if (node->key.source_type == cur->key.source_type && 269 node->key.target_type < cur->key.target_type) 270 break; 271 if (node->key.source_type == cur->key.source_type && 272 node->key.target_type == cur->key.target_type && 273 node->key.target_class < cur->key.target_class) 274 break; 275 } 276 return NULL; 277 } 278 279 void avtab_destroy(struct avtab *h) 280 { 281 int i; 282 struct avtab_node *cur, *temp; 283 284 if (!h) 285 return; 286 287 for (i = 0; i < h->nslot; i++) { 288 cur = h->htable[i]; 289 while (cur) { 290 temp = cur; 291 cur = cur->next; 292 if (temp->key.specified & AVTAB_XPERMS) 293 kmem_cache_free(avtab_xperms_cachep, 294 temp->datum.u.xperms); 295 kmem_cache_free(avtab_node_cachep, temp); 296 } 297 } 298 kvfree(h->htable); 299 h->htable = NULL; 300 h->nel = 0; 301 h->nslot = 0; 302 h->mask = 0; 303 } 304 305 void avtab_init(struct avtab *h) 306 { 307 h->htable = NULL; 308 h->nel = 0; 309 h->nslot = 0; 310 h->mask = 0; 311 } 312 313 static int avtab_alloc_common(struct avtab *h, u32 nslot) 314 { 315 if (!nslot) 316 return 0; 317 318 h->htable = kvcalloc(nslot, sizeof(void *), GFP_KERNEL); 319 if (!h->htable) 320 return -ENOMEM; 321 322 h->nslot = nslot; 323 h->mask = nslot - 1; 324 return 0; 325 } 326 327 int avtab_alloc(struct avtab *h, u32 nrules) 328 { 329 int rc; 330 u32 nslot = 0; 331 332 if (nrules != 0) { 333 u32 shift = 1; 334 u32 work = nrules >> 3; 335 while (work) { 336 work >>= 1; 337 shift++; 338 } 339 nslot = 1 << shift; 340 if (nslot > MAX_AVTAB_HASH_BUCKETS) 341 nslot = MAX_AVTAB_HASH_BUCKETS; 342 343 rc = avtab_alloc_common(h, nslot); 344 if (rc) 345 return rc; 346 } 347 348 pr_debug("SELinux: %d avtab hash slots, %d rules.\n", nslot, nrules); 349 return 0; 350 } 351 352 int avtab_alloc_dup(struct avtab *new, const struct avtab *orig) 353 { 354 return avtab_alloc_common(new, orig->nslot); 355 } 356 357 void avtab_hash_eval(struct avtab *h, char *tag) 358 { 359 int i, chain_len, slots_used, max_chain_len; 360 unsigned long long chain2_len_sum; 361 struct avtab_node *cur; 362 363 slots_used = 0; 364 max_chain_len = 0; 365 chain2_len_sum = 0; 366 for (i = 0; i < h->nslot; i++) { 367 cur = h->htable[i]; 368 if (cur) { 369 slots_used++; 370 chain_len = 0; 371 while (cur) { 372 chain_len++; 373 cur = cur->next; 374 } 375 376 if (chain_len > max_chain_len) 377 max_chain_len = chain_len; 378 chain2_len_sum += chain_len * chain_len; 379 } 380 } 381 382 pr_debug("SELinux: %s: %d entries and %d/%d buckets used, " 383 "longest chain length %d sum of chain length^2 %llu\n", 384 tag, h->nel, slots_used, h->nslot, max_chain_len, 385 chain2_len_sum); 386 } 387 388 static const uint16_t spec_order[] = { 389 AVTAB_ALLOWED, 390 AVTAB_AUDITDENY, 391 AVTAB_AUDITALLOW, 392 AVTAB_TRANSITION, 393 AVTAB_CHANGE, 394 AVTAB_MEMBER, 395 AVTAB_XPERMS_ALLOWED, 396 AVTAB_XPERMS_AUDITALLOW, 397 AVTAB_XPERMS_DONTAUDIT 398 }; 399 400 int avtab_read_item(struct avtab *a, void *fp, struct policydb *pol, 401 int (*insertf)(struct avtab *a, const struct avtab_key *k, 402 const struct avtab_datum *d, void *p), 403 void *p) 404 { 405 __le16 buf16[4]; 406 u16 enabled; 407 u32 items, items2, val, vers = pol->policyvers; 408 struct avtab_key key; 409 struct avtab_datum datum; 410 struct avtab_extended_perms xperms; 411 __le32 buf32[ARRAY_SIZE(xperms.perms.p)]; 412 int i, rc; 413 unsigned set; 414 415 memset(&key, 0, sizeof(struct avtab_key)); 416 memset(&datum, 0, sizeof(struct avtab_datum)); 417 418 if (vers < POLICYDB_VERSION_AVTAB) { 419 rc = next_entry(buf32, fp, sizeof(u32)); 420 if (rc) { 421 pr_err("SELinux: avtab: truncated entry\n"); 422 return rc; 423 } 424 items2 = le32_to_cpu(buf32[0]); 425 if (items2 > ARRAY_SIZE(buf32)) { 426 pr_err("SELinux: avtab: entry overflow\n"); 427 return -EINVAL; 428 429 } 430 rc = next_entry(buf32, fp, sizeof(u32)*items2); 431 if (rc) { 432 pr_err("SELinux: avtab: truncated entry\n"); 433 return rc; 434 } 435 items = 0; 436 437 val = le32_to_cpu(buf32[items++]); 438 key.source_type = (u16)val; 439 if (key.source_type != val) { 440 pr_err("SELinux: avtab: truncated source type\n"); 441 return -EINVAL; 442 } 443 val = le32_to_cpu(buf32[items++]); 444 key.target_type = (u16)val; 445 if (key.target_type != val) { 446 pr_err("SELinux: avtab: truncated target type\n"); 447 return -EINVAL; 448 } 449 val = le32_to_cpu(buf32[items++]); 450 key.target_class = (u16)val; 451 if (key.target_class != val) { 452 pr_err("SELinux: avtab: truncated target class\n"); 453 return -EINVAL; 454 } 455 456 val = le32_to_cpu(buf32[items++]); 457 enabled = (val & AVTAB_ENABLED_OLD) ? AVTAB_ENABLED : 0; 458 459 if (!(val & (AVTAB_AV | AVTAB_TYPE))) { 460 pr_err("SELinux: avtab: null entry\n"); 461 return -EINVAL; 462 } 463 if ((val & AVTAB_AV) && 464 (val & AVTAB_TYPE)) { 465 pr_err("SELinux: avtab: entry has both access vectors and types\n"); 466 return -EINVAL; 467 } 468 if (val & AVTAB_XPERMS) { 469 pr_err("SELinux: avtab: entry has extended permissions\n"); 470 return -EINVAL; 471 } 472 473 for (i = 0; i < ARRAY_SIZE(spec_order); i++) { 474 if (val & spec_order[i]) { 475 key.specified = spec_order[i] | enabled; 476 datum.u.data = le32_to_cpu(buf32[items++]); 477 rc = insertf(a, &key, &datum, p); 478 if (rc) 479 return rc; 480 } 481 } 482 483 if (items != items2) { 484 pr_err("SELinux: avtab: entry only had %d items, expected %d\n", 485 items2, items); 486 return -EINVAL; 487 } 488 return 0; 489 } 490 491 rc = next_entry(buf16, fp, sizeof(u16)*4); 492 if (rc) { 493 pr_err("SELinux: avtab: truncated entry\n"); 494 return rc; 495 } 496 497 items = 0; 498 key.source_type = le16_to_cpu(buf16[items++]); 499 key.target_type = le16_to_cpu(buf16[items++]); 500 key.target_class = le16_to_cpu(buf16[items++]); 501 key.specified = le16_to_cpu(buf16[items++]); 502 503 if (!policydb_type_isvalid(pol, key.source_type) || 504 !policydb_type_isvalid(pol, key.target_type) || 505 !policydb_class_isvalid(pol, key.target_class)) { 506 pr_err("SELinux: avtab: invalid type or class\n"); 507 return -EINVAL; 508 } 509 510 set = 0; 511 for (i = 0; i < ARRAY_SIZE(spec_order); i++) { 512 if (key.specified & spec_order[i]) 513 set++; 514 } 515 if (!set || set > 1) { 516 pr_err("SELinux: avtab: more than one specifier\n"); 517 return -EINVAL; 518 } 519 520 if ((vers < POLICYDB_VERSION_XPERMS_IOCTL) && 521 (key.specified & AVTAB_XPERMS)) { 522 pr_err("SELinux: avtab: policy version %u does not " 523 "support extended permissions rules and one " 524 "was specified\n", vers); 525 return -EINVAL; 526 } else if (key.specified & AVTAB_XPERMS) { 527 memset(&xperms, 0, sizeof(struct avtab_extended_perms)); 528 rc = next_entry(&xperms.specified, fp, sizeof(u8)); 529 if (rc) { 530 pr_err("SELinux: avtab: truncated entry\n"); 531 return rc; 532 } 533 rc = next_entry(&xperms.driver, fp, sizeof(u8)); 534 if (rc) { 535 pr_err("SELinux: avtab: truncated entry\n"); 536 return rc; 537 } 538 rc = next_entry(buf32, fp, sizeof(u32)*ARRAY_SIZE(xperms.perms.p)); 539 if (rc) { 540 pr_err("SELinux: avtab: truncated entry\n"); 541 return rc; 542 } 543 for (i = 0; i < ARRAY_SIZE(xperms.perms.p); i++) 544 xperms.perms.p[i] = le32_to_cpu(buf32[i]); 545 datum.u.xperms = &xperms; 546 } else { 547 rc = next_entry(buf32, fp, sizeof(u32)); 548 if (rc) { 549 pr_err("SELinux: avtab: truncated entry\n"); 550 return rc; 551 } 552 datum.u.data = le32_to_cpu(*buf32); 553 } 554 if ((key.specified & AVTAB_TYPE) && 555 !policydb_type_isvalid(pol, datum.u.data)) { 556 pr_err("SELinux: avtab: invalid type\n"); 557 return -EINVAL; 558 } 559 return insertf(a, &key, &datum, p); 560 } 561 562 static int avtab_insertf(struct avtab *a, const struct avtab_key *k, 563 const struct avtab_datum *d, void *p) 564 { 565 return avtab_insert(a, k, d); 566 } 567 568 int avtab_read(struct avtab *a, void *fp, struct policydb *pol) 569 { 570 int rc; 571 __le32 buf[1]; 572 u32 nel, i; 573 574 575 rc = next_entry(buf, fp, sizeof(u32)); 576 if (rc < 0) { 577 pr_err("SELinux: avtab: truncated table\n"); 578 goto bad; 579 } 580 nel = le32_to_cpu(buf[0]); 581 if (!nel) { 582 pr_err("SELinux: avtab: table is empty\n"); 583 rc = -EINVAL; 584 goto bad; 585 } 586 587 rc = avtab_alloc(a, nel); 588 if (rc) 589 goto bad; 590 591 for (i = 0; i < nel; i++) { 592 rc = avtab_read_item(a, fp, pol, avtab_insertf, NULL); 593 if (rc) { 594 if (rc == -ENOMEM) 595 pr_err("SELinux: avtab: out of memory\n"); 596 else if (rc == -EEXIST) 597 pr_err("SELinux: avtab: duplicate entry\n"); 598 599 goto bad; 600 } 601 } 602 603 rc = 0; 604 out: 605 return rc; 606 607 bad: 608 avtab_destroy(a); 609 goto out; 610 } 611 612 int avtab_write_item(struct policydb *p, const struct avtab_node *cur, void *fp) 613 { 614 __le16 buf16[4]; 615 __le32 buf32[ARRAY_SIZE(cur->datum.u.xperms->perms.p)]; 616 int rc; 617 unsigned int i; 618 619 buf16[0] = cpu_to_le16(cur->key.source_type); 620 buf16[1] = cpu_to_le16(cur->key.target_type); 621 buf16[2] = cpu_to_le16(cur->key.target_class); 622 buf16[3] = cpu_to_le16(cur->key.specified); 623 rc = put_entry(buf16, sizeof(u16), 4, fp); 624 if (rc) 625 return rc; 626 627 if (cur->key.specified & AVTAB_XPERMS) { 628 rc = put_entry(&cur->datum.u.xperms->specified, sizeof(u8), 1, fp); 629 if (rc) 630 return rc; 631 rc = put_entry(&cur->datum.u.xperms->driver, sizeof(u8), 1, fp); 632 if (rc) 633 return rc; 634 for (i = 0; i < ARRAY_SIZE(cur->datum.u.xperms->perms.p); i++) 635 buf32[i] = cpu_to_le32(cur->datum.u.xperms->perms.p[i]); 636 rc = put_entry(buf32, sizeof(u32), 637 ARRAY_SIZE(cur->datum.u.xperms->perms.p), fp); 638 } else { 639 buf32[0] = cpu_to_le32(cur->datum.u.data); 640 rc = put_entry(buf32, sizeof(u32), 1, fp); 641 } 642 if (rc) 643 return rc; 644 return 0; 645 } 646 647 int avtab_write(struct policydb *p, struct avtab *a, void *fp) 648 { 649 unsigned int i; 650 int rc = 0; 651 struct avtab_node *cur; 652 __le32 buf[1]; 653 654 buf[0] = cpu_to_le32(a->nel); 655 rc = put_entry(buf, sizeof(u32), 1, fp); 656 if (rc) 657 return rc; 658 659 for (i = 0; i < a->nslot; i++) { 660 for (cur = a->htable[i]; cur; 661 cur = cur->next) { 662 rc = avtab_write_item(p, cur, fp); 663 if (rc) 664 return rc; 665 } 666 } 667 668 return rc; 669 } 670 671 void __init avtab_cache_init(void) 672 { 673 avtab_node_cachep = kmem_cache_create("avtab_node", 674 sizeof(struct avtab_node), 675 0, SLAB_PANIC, NULL); 676 avtab_xperms_cachep = kmem_cache_create("avtab_extended_perms", 677 sizeof(struct avtab_extended_perms), 678 0, SLAB_PANIC, NULL); 679 } 680