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 */
avtab_hash(const struct avtab_key * keyp,u32 mask)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) { \
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*
avtab_insert_node(struct avtab * h,int hvalue,struct avtab_node * prev,struct avtab_node * cur,const struct avtab_key * key,const struct avtab_datum * datum)69 avtab_insert_node(struct avtab *h, int hvalue,
70 struct avtab_node *prev, struct avtab_node *cur,
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
avtab_insert(struct avtab * h,const struct avtab_key * key,const struct avtab_datum * datum)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, cur, 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 */
avtab_insert_nonunique(struct avtab * h,const struct avtab_key * key,const struct avtab_datum * datum)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, cur, key, datum);
181 }
182
avtab_search(struct avtab * h,const struct avtab_key * key)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 */
avtab_search_node(struct avtab * h,const struct avtab_key * key)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*
avtab_search_node_next(struct avtab_node * node,int specified)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
avtab_destroy(struct avtab * h)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
avtab_init(struct avtab * h)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
avtab_alloc_common(struct avtab * h,u32 nslot)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
avtab_alloc(struct avtab * h,u32 nrules)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
avtab_alloc_dup(struct avtab * new,const struct avtab * orig)352 int avtab_alloc_dup(struct avtab *new, const struct avtab *orig)
353 {
354 return avtab_alloc_common(new, orig->nslot);
355 }
356
avtab_hash_eval(struct avtab * h,char * tag)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 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
avtab_read_item(struct avtab * a,void * fp,struct policydb * pol,int (* insertf)(struct avtab * a,const struct avtab_key * k,const struct avtab_datum * d,void * p),void * p)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
avtab_insertf(struct avtab * a,const struct avtab_key * k,const struct avtab_datum * d,void * p)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
avtab_read(struct avtab * a,void * fp,struct policydb * pol)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
avtab_write_item(struct policydb * p,const struct avtab_node * cur,void * fp)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
avtab_write(struct policydb * p,struct avtab * a,void * fp)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
avtab_cache_init(void)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
