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 26static struct kmem_cache *avtab_node_cachep; 27static struct kmem_cache *avtab_xperms_cachep; 28 29/* Based on MurmurHash3, written by Austin Appleby and placed in the 30 * public domain. 31 */ 32static 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 68static struct avtab_node* 69avtab_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 106static 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 || !h->nslot) 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 */ 150struct avtab_node * 151avtab_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 || !h->nslot) 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 181struct 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 || !h->nslot) 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 */ 216struct avtab_node* 217avtab_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 || !h->nslot) 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 248struct avtab_node* 249avtab_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 277void 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->nel = 0; 299 h->nslot = 0; 300 h->mask = 0; 301} 302 303void avtab_init(struct avtab *h) 304{ 305 h->htable = NULL; 306 h->nel = 0; 307 h->nslot = 0; 308 h->mask = 0; 309} 310 311static int avtab_alloc_common(struct avtab *h, u32 nslot) 312{ 313 if (!nslot) 314 return 0; 315 316 h->htable = kvcalloc(nslot, sizeof(void *), GFP_KERNEL); 317 if (!h->htable) 318 return -ENOMEM; 319 320 h->nslot = nslot; 321 h->mask = nslot - 1; 322 return 0; 323} 324 325int avtab_alloc(struct avtab *h, u32 nrules) 326{ 327 int rc; 328 u32 nslot = 0; 329 330 if (nrules != 0) { 331 u32 shift = 1; 332 u32 work = nrules >> 3; 333 while (work) { 334 work >>= 1; 335 shift++; 336 } 337 nslot = 1 << shift; 338 if (nslot > MAX_AVTAB_HASH_BUCKETS) 339 nslot = MAX_AVTAB_HASH_BUCKETS; 340 341 rc = avtab_alloc_common(h, nslot); 342 if (rc) 343 return rc; 344 } 345 346 pr_debug("SELinux: %d avtab hash slots, %d rules.\n", nslot, nrules); 347 return 0; 348} 349 350int avtab_alloc_dup(struct avtab *new, const struct avtab *orig) 351{ 352 return avtab_alloc_common(new, orig->nslot); 353} 354 355void avtab_hash_eval(struct avtab *h, char *tag) 356{ 357 int i, chain_len, slots_used, max_chain_len; 358 unsigned long long chain2_len_sum; 359 struct avtab_node *cur; 360 361 slots_used = 0; 362 max_chain_len = 0; 363 chain2_len_sum = 0; 364 for (i = 0; i < h->nslot; i++) { 365 cur = h->htable[i]; 366 if (cur) { 367 slots_used++; 368 chain_len = 0; 369 while (cur) { 370 chain_len++; 371 cur = cur->next; 372 } 373 374 if (chain_len > max_chain_len) 375 max_chain_len = chain_len; 376 chain2_len_sum += chain_len * chain_len; 377 } 378 } 379 380 pr_debug("SELinux: %s: %d entries and %d/%d buckets used, " 381 "longest chain length %d sum of chain length^2 %llu\n", 382 tag, h->nel, slots_used, h->nslot, max_chain_len, 383 chain2_len_sum); 384} 385 386static uint16_t spec_order[] = { 387 AVTAB_ALLOWED, 388 AVTAB_AUDITDENY, 389 AVTAB_AUDITALLOW, 390 AVTAB_TRANSITION, 391 AVTAB_CHANGE, 392 AVTAB_MEMBER, 393 AVTAB_XPERMS_ALLOWED, 394 AVTAB_XPERMS_AUDITALLOW, 395 AVTAB_XPERMS_DONTAUDIT 396}; 397 398int avtab_read_item(struct avtab *a, void *fp, struct policydb *pol, 399 int (*insertf)(struct avtab *a, struct avtab_key *k, 400 struct avtab_datum *d, void *p), 401 void *p) 402{ 403 __le16 buf16[4]; 404 u16 enabled; 405 u32 items, items2, val, vers = pol->policyvers; 406 struct avtab_key key; 407 struct avtab_datum datum; 408 struct avtab_extended_perms xperms; 409 __le32 buf32[ARRAY_SIZE(xperms.perms.p)]; 410 int i, rc; 411 unsigned set; 412 413 memset(&key, 0, sizeof(struct avtab_key)); 414 memset(&datum, 0, sizeof(struct avtab_datum)); 415 416 if (vers < POLICYDB_VERSION_AVTAB) { 417 rc = next_entry(buf32, fp, sizeof(u32)); 418 if (rc) { 419 pr_err("SELinux: avtab: truncated entry\n"); 420 return rc; 421 } 422 items2 = le32_to_cpu(buf32[0]); 423 if (items2 > ARRAY_SIZE(buf32)) { 424 pr_err("SELinux: avtab: entry overflow\n"); 425 return -EINVAL; 426 427 } 428 rc = next_entry(buf32, fp, sizeof(u32)*items2); 429 if (rc) { 430 pr_err("SELinux: avtab: truncated entry\n"); 431 return rc; 432 } 433 items = 0; 434 435 val = le32_to_cpu(buf32[items++]); 436 key.source_type = (u16)val; 437 if (key.source_type != val) { 438 pr_err("SELinux: avtab: truncated source type\n"); 439 return -EINVAL; 440 } 441 val = le32_to_cpu(buf32[items++]); 442 key.target_type = (u16)val; 443 if (key.target_type != val) { 444 pr_err("SELinux: avtab: truncated target type\n"); 445 return -EINVAL; 446 } 447 val = le32_to_cpu(buf32[items++]); 448 key.target_class = (u16)val; 449 if (key.target_class != val) { 450 pr_err("SELinux: avtab: truncated target class\n"); 451 return -EINVAL; 452 } 453 454 val = le32_to_cpu(buf32[items++]); 455 enabled = (val & AVTAB_ENABLED_OLD) ? AVTAB_ENABLED : 0; 456 457 if (!(val & (AVTAB_AV | AVTAB_TYPE))) { 458 pr_err("SELinux: avtab: null entry\n"); 459 return -EINVAL; 460 } 461 if ((val & AVTAB_AV) && 462 (val & AVTAB_TYPE)) { 463 pr_err("SELinux: avtab: entry has both access vectors and types\n"); 464 return -EINVAL; 465 } 466 if (val & AVTAB_XPERMS) { 467 pr_err("SELinux: avtab: entry has extended permissions\n"); 468 return -EINVAL; 469 } 470 471 for (i = 0; i < ARRAY_SIZE(spec_order); i++) { 472 if (val & spec_order[i]) { 473 key.specified = spec_order[i] | enabled; 474 datum.u.data = le32_to_cpu(buf32[items++]); 475 rc = insertf(a, &key, &datum, p); 476 if (rc) 477 return rc; 478 } 479 } 480 481 if (items != items2) { 482 pr_err("SELinux: avtab: entry only had %d items, expected %d\n", 483 items2, items); 484 return -EINVAL; 485 } 486 return 0; 487 } 488 489 rc = next_entry(buf16, fp, sizeof(u16)*4); 490 if (rc) { 491 pr_err("SELinux: avtab: truncated entry\n"); 492 return rc; 493 } 494 495 items = 0; 496 key.source_type = le16_to_cpu(buf16[items++]); 497 key.target_type = le16_to_cpu(buf16[items++]); 498 key.target_class = le16_to_cpu(buf16[items++]); 499 key.specified = le16_to_cpu(buf16[items++]); 500 501 if (!policydb_type_isvalid(pol, key.source_type) || 502 !policydb_type_isvalid(pol, key.target_type) || 503 !policydb_class_isvalid(pol, key.target_class)) { 504 pr_err("SELinux: avtab: invalid type or class\n"); 505 return -EINVAL; 506 } 507 508 set = 0; 509 for (i = 0; i < ARRAY_SIZE(spec_order); i++) { 510 if (key.specified & spec_order[i]) 511 set++; 512 } 513 if (!set || set > 1) { 514 pr_err("SELinux: avtab: more than one specifier\n"); 515 return -EINVAL; 516 } 517 518 if ((vers < POLICYDB_VERSION_XPERMS_IOCTL) && 519 (key.specified & AVTAB_XPERMS)) { 520 pr_err("SELinux: avtab: policy version %u does not " 521 "support extended permissions rules and one " 522 "was specified\n", vers); 523 return -EINVAL; 524 } else if (key.specified & AVTAB_XPERMS) { 525 memset(&xperms, 0, sizeof(struct avtab_extended_perms)); 526 rc = next_entry(&xperms.specified, fp, sizeof(u8)); 527 if (rc) { 528 pr_err("SELinux: avtab: truncated entry\n"); 529 return rc; 530 } 531 rc = next_entry(&xperms.driver, fp, sizeof(u8)); 532 if (rc) { 533 pr_err("SELinux: avtab: truncated entry\n"); 534 return rc; 535 } 536 rc = next_entry(buf32, fp, sizeof(u32)*ARRAY_SIZE(xperms.perms.p)); 537 if (rc) { 538 pr_err("SELinux: avtab: truncated entry\n"); 539 return rc; 540 } 541 for (i = 0; i < ARRAY_SIZE(xperms.perms.p); i++) 542 xperms.perms.p[i] = le32_to_cpu(buf32[i]); 543 datum.u.xperms = &xperms; 544 } else { 545 rc = next_entry(buf32, fp, sizeof(u32)); 546 if (rc) { 547 pr_err("SELinux: avtab: truncated entry\n"); 548 return rc; 549 } 550 datum.u.data = le32_to_cpu(*buf32); 551 } 552 if ((key.specified & AVTAB_TYPE) && 553 !policydb_type_isvalid(pol, datum.u.data)) { 554 pr_err("SELinux: avtab: invalid type\n"); 555 return -EINVAL; 556 } 557 return insertf(a, &key, &datum, p); 558} 559 560static int avtab_insertf(struct avtab *a, struct avtab_key *k, 561 struct avtab_datum *d, void *p) 562{ 563 return avtab_insert(a, k, d); 564} 565 566int avtab_read(struct avtab *a, void *fp, struct policydb *pol) 567{ 568 int rc; 569 __le32 buf[1]; 570 u32 nel, i; 571 572 573 rc = next_entry(buf, fp, sizeof(u32)); 574 if (rc < 0) { 575 pr_err("SELinux: avtab: truncated table\n"); 576 goto bad; 577 } 578 nel = le32_to_cpu(buf[0]); 579 if (!nel) { 580 pr_err("SELinux: avtab: table is empty\n"); 581 rc = -EINVAL; 582 goto bad; 583 } 584 585 rc = avtab_alloc(a, nel); 586 if (rc) 587 goto bad; 588 589 for (i = 0; i < nel; i++) { 590 rc = avtab_read_item(a, fp, pol, avtab_insertf, NULL); 591 if (rc) { 592 if (rc == -ENOMEM) 593 pr_err("SELinux: avtab: out of memory\n"); 594 else if (rc == -EEXIST) 595 pr_err("SELinux: avtab: duplicate entry\n"); 596 597 goto bad; 598 } 599 } 600 601 rc = 0; 602out: 603 return rc; 604 605bad: 606 avtab_destroy(a); 607 goto out; 608} 609 610int avtab_write_item(struct policydb *p, struct avtab_node *cur, void *fp) 611{ 612 __le16 buf16[4]; 613 __le32 buf32[ARRAY_SIZE(cur->datum.u.xperms->perms.p)]; 614 int rc; 615 unsigned int i; 616 617 buf16[0] = cpu_to_le16(cur->key.source_type); 618 buf16[1] = cpu_to_le16(cur->key.target_type); 619 buf16[2] = cpu_to_le16(cur->key.target_class); 620 buf16[3] = cpu_to_le16(cur->key.specified); 621 rc = put_entry(buf16, sizeof(u16), 4, fp); 622 if (rc) 623 return rc; 624 625 if (cur->key.specified & AVTAB_XPERMS) { 626 rc = put_entry(&cur->datum.u.xperms->specified, sizeof(u8), 1, fp); 627 if (rc) 628 return rc; 629 rc = put_entry(&cur->datum.u.xperms->driver, sizeof(u8), 1, fp); 630 if (rc) 631 return rc; 632 for (i = 0; i < ARRAY_SIZE(cur->datum.u.xperms->perms.p); i++) 633 buf32[i] = cpu_to_le32(cur->datum.u.xperms->perms.p[i]); 634 rc = put_entry(buf32, sizeof(u32), 635 ARRAY_SIZE(cur->datum.u.xperms->perms.p), fp); 636 } else { 637 buf32[0] = cpu_to_le32(cur->datum.u.data); 638 rc = put_entry(buf32, sizeof(u32), 1, fp); 639 } 640 if (rc) 641 return rc; 642 return 0; 643} 644 645int avtab_write(struct policydb *p, struct avtab *a, void *fp) 646{ 647 unsigned int i; 648 int rc = 0; 649 struct avtab_node *cur; 650 __le32 buf[1]; 651 652 buf[0] = cpu_to_le32(a->nel); 653 rc = put_entry(buf, sizeof(u32), 1, fp); 654 if (rc) 655 return rc; 656 657 for (i = 0; i < a->nslot; i++) { 658 for (cur = a->htable[i]; cur; 659 cur = cur->next) { 660 rc = avtab_write_item(p, cur, fp); 661 if (rc) 662 return rc; 663 } 664 } 665 666 return rc; 667} 668 669void __init avtab_cache_init(void) 670{ 671 avtab_node_cachep = kmem_cache_create("avtab_node", 672 sizeof(struct avtab_node), 673 0, SLAB_PANIC, NULL); 674 avtab_xperms_cachep = kmem_cache_create("avtab_extended_perms", 675 sizeof(struct avtab_extended_perms), 676 0, SLAB_PANIC, NULL); 677} 678