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