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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 __ro_after_init;
27static struct kmem_cache *avtab_xperms_cachep __ro_after_init;
28
29
30
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
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
147
148
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
214
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
