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