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