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1// SPDX-License-Identifier: GPL-2.0-only
2/* Authors: Karl MacMillan <kmacmillan@tresys.com>
3 * Frank Mayer <mayerf@tresys.com>
4 *
5 * Copyright (C) 2003 - 2004 Tresys Technology, LLC
6 */
7
8#include <linux/kernel.h>
9#include <linux/errno.h>
10#include <linux/string.h>
11#include <linux/spinlock.h>
12#include <linux/slab.h>
13
14#include "security.h"
15#include "conditional.h"
16#include "services.h"
17
18/*
19 * cond_evaluate_expr evaluates a conditional expr
20 * in reverse polish notation. It returns true (1), false (0),
21 * or undefined (-1). Undefined occurs when the expression
22 * exceeds the stack depth of COND_EXPR_MAXDEPTH.
23 */
24static int cond_evaluate_expr(struct policydb *p, struct cond_expr *expr)
25{
26 u32 i;
27 int s[COND_EXPR_MAXDEPTH];
28 int sp = -1;
29
30 if (expr->len == 0)
31 return -1;
32
33 for (i = 0; i < expr->len; i++) {
34 struct cond_expr_node *node = &expr->nodes[i];
35
36 switch (node->expr_type) {
37 case COND_BOOL:
38 if (sp == (COND_EXPR_MAXDEPTH - 1))
39 return -1;
40 sp++;
41 s[sp] = p->bool_val_to_struct[node->bool - 1]->state;
42 break;
43 case COND_NOT:
44 if (sp < 0)
45 return -1;
46 s[sp] = !s[sp];
47 break;
48 case COND_OR:
49 if (sp < 1)
50 return -1;
51 sp--;
52 s[sp] |= s[sp + 1];
53 break;
54 case COND_AND:
55 if (sp < 1)
56 return -1;
57 sp--;
58 s[sp] &= s[sp + 1];
59 break;
60 case COND_XOR:
61 if (sp < 1)
62 return -1;
63 sp--;
64 s[sp] ^= s[sp + 1];
65 break;
66 case COND_EQ:
67 if (sp < 1)
68 return -1;
69 sp--;
70 s[sp] = (s[sp] == s[sp + 1]);
71 break;
72 case COND_NEQ:
73 if (sp < 1)
74 return -1;
75 sp--;
76 s[sp] = (s[sp] != s[sp + 1]);
77 break;
78 default:
79 return -1;
80 }
81 }
82 return s[0];
83}
84
85/*
86 * evaluate_cond_node evaluates the conditional stored in
87 * a struct cond_node and if the result is different than the
88 * current state of the node it sets the rules in the true/false
89 * list appropriately. If the result of the expression is undefined
90 * all of the rules are disabled for safety.
91 */
92static void evaluate_cond_node(struct policydb *p, struct cond_node *node)
93{
94 struct avtab_node *avnode;
95 int new_state;
96 u32 i;
97
98 new_state = cond_evaluate_expr(p, &node->expr);
99 if (new_state != node->cur_state) {
100 node->cur_state = new_state;
101 if (new_state == -1)
102 pr_err("SELinux: expression result was undefined - disabling all rules.\n");
103 /* turn the rules on or off */
104 for (i = 0; i < node->true_list.len; i++) {
105 avnode = node->true_list.nodes[i];
106 if (new_state <= 0)
107 avnode->key.specified &= ~AVTAB_ENABLED;
108 else
109 avnode->key.specified |= AVTAB_ENABLED;
110 }
111
112 for (i = 0; i < node->false_list.len; i++) {
113 avnode = node->false_list.nodes[i];
114 /* -1 or 1 */
115 if (new_state)
116 avnode->key.specified &= ~AVTAB_ENABLED;
117 else
118 avnode->key.specified |= AVTAB_ENABLED;
119 }
120 }
121}
122
123void evaluate_cond_nodes(struct policydb *p)
124{
125 u32 i;
126
127 for (i = 0; i < p->cond_list_len; i++)
128 evaluate_cond_node(p, &p->cond_list[i]);
129}
130
131void cond_policydb_init(struct policydb *p)
132{
133 p->bool_val_to_struct = NULL;
134 p->cond_list = NULL;
135 p->cond_list_len = 0;
136
137 avtab_init(&p->te_cond_avtab);
138}
139
140static void cond_node_destroy(struct cond_node *node)
141{
142 kfree(node->expr.nodes);
143 /* the avtab_ptr_t nodes are destroyed by the avtab */
144 kfree(node->true_list.nodes);
145 kfree(node->false_list.nodes);
146}
147
148static void cond_list_destroy(struct policydb *p)
149{
150 u32 i;
151
152 for (i = 0; i < p->cond_list_len; i++)
153 cond_node_destroy(&p->cond_list[i]);
154 kfree(p->cond_list);
155 p->cond_list = NULL;
156 p->cond_list_len = 0;
157}
158
159void cond_policydb_destroy(struct policydb *p)
160{
161 kfree(p->bool_val_to_struct);
162 avtab_destroy(&p->te_cond_avtab);
163 cond_list_destroy(p);
164}
165
166int cond_init_bool_indexes(struct policydb *p)
167{
168 kfree(p->bool_val_to_struct);
169 p->bool_val_to_struct = kmalloc_array(p->p_bools.nprim,
170 sizeof(*p->bool_val_to_struct),
171 GFP_KERNEL);
172 if (!p->bool_val_to_struct)
173 return -ENOMEM;
174 return 0;
175}
176
177int cond_destroy_bool(void *key, void *datum, void *p)
178{
179 kfree(key);
180 kfree(datum);
181 return 0;
182}
183
184int cond_index_bool(void *key, void *datum, void *datap)
185{
186 struct policydb *p;
187 struct cond_bool_datum *booldatum;
188
189 booldatum = datum;
190 p = datap;
191
192 if (!booldatum->value || booldatum->value > p->p_bools.nprim)
193 return -EINVAL;
194
195 p->sym_val_to_name[SYM_BOOLS][booldatum->value - 1] = key;
196 p->bool_val_to_struct[booldatum->value - 1] = booldatum;
197
198 return 0;
199}
200
201static int bool_isvalid(struct cond_bool_datum *b)
202{
203 if (!(b->state == 0 || b->state == 1))
204 return 0;
205 return 1;
206}
207
208int cond_read_bool(struct policydb *p, struct symtab *s, void *fp)
209{
210 char *key = NULL;
211 struct cond_bool_datum *booldatum;
212 __le32 buf[3];
213 u32 len;
214 int rc;
215
216 booldatum = kzalloc(sizeof(*booldatum), GFP_KERNEL);
217 if (!booldatum)
218 return -ENOMEM;
219
220 rc = next_entry(buf, fp, sizeof(buf));
221 if (rc)
222 goto err;
223
224 booldatum->value = le32_to_cpu(buf[0]);
225 booldatum->state = le32_to_cpu(buf[1]);
226
227 rc = -EINVAL;
228 if (!bool_isvalid(booldatum))
229 goto err;
230
231 len = le32_to_cpu(buf[2]);
232 if (((len == 0) || (len == (u32)-1)))
233 goto err;
234
235 rc = -ENOMEM;
236 key = kmalloc(len + 1, GFP_KERNEL);
237 if (!key)
238 goto err;
239 rc = next_entry(key, fp, len);
240 if (rc)
241 goto err;
242 key[len] = '\0';
243 rc = symtab_insert(s, key, booldatum);
244 if (rc)
245 goto err;
246
247 return 0;
248err:
249 cond_destroy_bool(key, booldatum, NULL);
250 return rc;
251}
252
253struct cond_insertf_data {
254 struct policydb *p;
255 struct avtab_node **dst;
256 struct cond_av_list *other;
257};
258
259static int cond_insertf(struct avtab *a, const struct avtab_key *k,
260 const struct avtab_datum *d, void *ptr)
261{
262 struct cond_insertf_data *data = ptr;
263 struct policydb *p = data->p;
264 struct cond_av_list *other = data->other;
265 struct avtab_node *node_ptr;
266 u32 i;
267 bool found;
268
269 /*
270 * For type rules we have to make certain there aren't any
271 * conflicting rules by searching the te_avtab and the
272 * cond_te_avtab.
273 */
274 if (k->specified & AVTAB_TYPE) {
275 if (avtab_search(&p->te_avtab, k)) {
276 pr_err("SELinux: type rule already exists outside of a conditional.\n");
277 return -EINVAL;
278 }
279 /*
280 * If we are reading the false list other will be a pointer to
281 * the true list. We can have duplicate entries if there is only
282 * 1 other entry and it is in our true list.
283 *
284 * If we are reading the true list (other == NULL) there shouldn't
285 * be any other entries.
286 */
287 if (other) {
288 node_ptr = avtab_search_node(&p->te_cond_avtab, k);
289 if (node_ptr) {
290 if (avtab_search_node_next(node_ptr, k->specified)) {
291 pr_err("SELinux: too many conflicting type rules.\n");
292 return -EINVAL;
293 }
294 found = false;
295 for (i = 0; i < other->len; i++) {
296 if (other->nodes[i] == node_ptr) {
297 found = true;
298 break;
299 }
300 }
301 if (!found) {
302 pr_err("SELinux: conflicting type rules.\n");
303 return -EINVAL;
304 }
305 }
306 } else {
307 if (avtab_search(&p->te_cond_avtab, k)) {
308 pr_err("SELinux: conflicting type rules when adding type rule for true.\n");
309 return -EINVAL;
310 }
311 }
312 }
313
314 node_ptr = avtab_insert_nonunique(&p->te_cond_avtab, k, d);
315 if (!node_ptr) {
316 pr_err("SELinux: could not insert rule.\n");
317 return -ENOMEM;
318 }
319
320 *data->dst = node_ptr;
321 return 0;
322}
323
324static int cond_read_av_list(struct policydb *p, void *fp,
325 struct cond_av_list *list,
326 struct cond_av_list *other)
327{
328 int rc;
329 __le32 buf[1];
330 u32 i, len;
331 struct cond_insertf_data data;
332
333 rc = next_entry(buf, fp, sizeof(u32));
334 if (rc)
335 return rc;
336
337 len = le32_to_cpu(buf[0]);
338 if (len == 0)
339 return 0;
340
341 list->nodes = kcalloc(len, sizeof(*list->nodes), GFP_KERNEL);
342 if (!list->nodes)
343 return -ENOMEM;
344
345 data.p = p;
346 data.other = other;
347 for (i = 0; i < len; i++) {
348 data.dst = &list->nodes[i];
349 rc = avtab_read_item(&p->te_cond_avtab, fp, p, cond_insertf,
350 &data);
351 if (rc) {
352 kfree(list->nodes);
353 list->nodes = NULL;
354 return rc;
355 }
356 }
357
358 list->len = len;
359 return 0;
360}
361
362static int expr_node_isvalid(struct policydb *p, struct cond_expr_node *expr)
363{
364 if (expr->expr_type <= 0 || expr->expr_type > COND_LAST) {
365 pr_err("SELinux: conditional expressions uses unknown operator.\n");
366 return 0;
367 }
368
369 if (expr->bool > p->p_bools.nprim) {
370 pr_err("SELinux: conditional expressions uses unknown bool.\n");
371 return 0;
372 }
373 return 1;
374}
375
376static int cond_read_node(struct policydb *p, struct cond_node *node, void *fp)
377{
378 __le32 buf[2];
379 u32 i, len;
380 int rc;
381
382 rc = next_entry(buf, fp, sizeof(u32) * 2);
383 if (rc)
384 return rc;
385
386 node->cur_state = le32_to_cpu(buf[0]);
387
388 /* expr */
389 len = le32_to_cpu(buf[1]);
390 node->expr.nodes = kcalloc(len, sizeof(*node->expr.nodes), GFP_KERNEL);
391 if (!node->expr.nodes)
392 return -ENOMEM;
393
394 node->expr.len = len;
395
396 for (i = 0; i < len; i++) {
397 struct cond_expr_node *expr = &node->expr.nodes[i];
398
399 rc = next_entry(buf, fp, sizeof(u32) * 2);
400 if (rc)
401 return rc;
402
403 expr->expr_type = le32_to_cpu(buf[0]);
404 expr->bool = le32_to_cpu(buf[1]);
405
406 if (!expr_node_isvalid(p, expr))
407 return -EINVAL;
408 }
409
410 rc = cond_read_av_list(p, fp, &node->true_list, NULL);
411 if (rc)
412 return rc;
413 return cond_read_av_list(p, fp, &node->false_list, &node->true_list);
414}
415
416int cond_read_list(struct policydb *p, void *fp)
417{
418 __le32 buf[1];
419 u32 i, len;
420 int rc;
421
422 rc = next_entry(buf, fp, sizeof(buf));
423 if (rc)
424 return rc;
425
426 len = le32_to_cpu(buf[0]);
427
428 p->cond_list = kcalloc(len, sizeof(*p->cond_list), GFP_KERNEL);
429 if (!p->cond_list)
430 return -ENOMEM;
431
432 rc = avtab_alloc(&(p->te_cond_avtab), p->te_avtab.nel);
433 if (rc)
434 goto err;
435
436 p->cond_list_len = len;
437
438 for (i = 0; i < len; i++) {
439 rc = cond_read_node(p, &p->cond_list[i], fp);
440 if (rc)
441 goto err;
442 }
443 return 0;
444err:
445 cond_list_destroy(p);
446 return rc;
447}
448
449int cond_write_bool(void *vkey, void *datum, void *ptr)
450{
451 char *key = vkey;
452 struct cond_bool_datum *booldatum = datum;
453 struct policy_data *pd = ptr;
454 void *fp = pd->fp;
455 __le32 buf[3];
456 u32 len;
457 int rc;
458
459 len = strlen(key);
460 buf[0] = cpu_to_le32(booldatum->value);
461 buf[1] = cpu_to_le32(booldatum->state);
462 buf[2] = cpu_to_le32(len);
463 rc = put_entry(buf, sizeof(u32), 3, fp);
464 if (rc)
465 return rc;
466 rc = put_entry(key, 1, len, fp);
467 if (rc)
468 return rc;
469 return 0;
470}
471
472/*
473 * cond_write_cond_av_list doesn't write out the av_list nodes.
474 * Instead it writes out the key/value pairs from the avtab. This
475 * is necessary because there is no way to uniquely identifying rules
476 * in the avtab so it is not possible to associate individual rules
477 * in the avtab with a conditional without saving them as part of
478 * the conditional. This means that the avtab with the conditional
479 * rules will not be saved but will be rebuilt on policy load.
480 */
481static int cond_write_av_list(struct policydb *p,
482 struct cond_av_list *list, struct policy_file *fp)
483{
484 __le32 buf[1];
485 u32 i;
486 int rc;
487
488 buf[0] = cpu_to_le32(list->len);
489 rc = put_entry(buf, sizeof(u32), 1, fp);
490 if (rc)
491 return rc;
492
493 for (i = 0; i < list->len; i++) {
494 rc = avtab_write_item(p, list->nodes[i], fp);
495 if (rc)
496 return rc;
497 }
498
499 return 0;
500}
501
502static int cond_write_node(struct policydb *p, struct cond_node *node,
503 struct policy_file *fp)
504{
505 __le32 buf[2];
506 int rc;
507 u32 i;
508
509 buf[0] = cpu_to_le32(node->cur_state);
510 rc = put_entry(buf, sizeof(u32), 1, fp);
511 if (rc)
512 return rc;
513
514 buf[0] = cpu_to_le32(node->expr.len);
515 rc = put_entry(buf, sizeof(u32), 1, fp);
516 if (rc)
517 return rc;
518
519 for (i = 0; i < node->expr.len; i++) {
520 buf[0] = cpu_to_le32(node->expr.nodes[i].expr_type);
521 buf[1] = cpu_to_le32(node->expr.nodes[i].bool);
522 rc = put_entry(buf, sizeof(u32), 2, fp);
523 if (rc)
524 return rc;
525 }
526
527 rc = cond_write_av_list(p, &node->true_list, fp);
528 if (rc)
529 return rc;
530 rc = cond_write_av_list(p, &node->false_list, fp);
531 if (rc)
532 return rc;
533
534 return 0;
535}
536
537int cond_write_list(struct policydb *p, void *fp)
538{
539 u32 i;
540 __le32 buf[1];
541 int rc;
542
543 buf[0] = cpu_to_le32(p->cond_list_len);
544 rc = put_entry(buf, sizeof(u32), 1, fp);
545 if (rc)
546 return rc;
547
548 for (i = 0; i < p->cond_list_len; i++) {
549 rc = cond_write_node(p, &p->cond_list[i], fp);
550 if (rc)
551 return rc;
552 }
553
554 return 0;
555}
556
557void cond_compute_xperms(struct avtab *ctab, struct avtab_key *key,
558 struct extended_perms_decision *xpermd)
559{
560 struct avtab_node *node;
561
562 if (!ctab || !key || !xpermd)
563 return;
564
565 for (node = avtab_search_node(ctab, key); node;
566 node = avtab_search_node_next(node, key->specified)) {
567 if (node->key.specified & AVTAB_ENABLED)
568 services_compute_xperms_decision(xpermd, node);
569 }
570}
571/* Determine whether additional permissions are granted by the conditional
572 * av table, and if so, add them to the result
573 */
574void cond_compute_av(struct avtab *ctab, struct avtab_key *key,
575 struct av_decision *avd, struct extended_perms *xperms)
576{
577 struct avtab_node *node;
578
579 if (!ctab || !key || !avd)
580 return;
581
582 for (node = avtab_search_node(ctab, key); node;
583 node = avtab_search_node_next(node, key->specified)) {
584 if ((u16)(AVTAB_ALLOWED|AVTAB_ENABLED) ==
585 (node->key.specified & (AVTAB_ALLOWED|AVTAB_ENABLED)))
586 avd->allowed |= node->datum.u.data;
587 if ((u16)(AVTAB_AUDITDENY|AVTAB_ENABLED) ==
588 (node->key.specified & (AVTAB_AUDITDENY|AVTAB_ENABLED)))
589 /* Since a '0' in an auditdeny mask represents a
590 * permission we do NOT want to audit (dontaudit), we use
591 * the '&' operand to ensure that all '0's in the mask
592 * are retained (much unlike the allow and auditallow cases).
593 */
594 avd->auditdeny &= node->datum.u.data;
595 if ((u16)(AVTAB_AUDITALLOW|AVTAB_ENABLED) ==
596 (node->key.specified & (AVTAB_AUDITALLOW|AVTAB_ENABLED)))
597 avd->auditallow |= node->datum.u.data;
598 if (xperms && (node->key.specified & AVTAB_ENABLED) &&
599 (node->key.specified & AVTAB_XPERMS))
600 services_compute_xperms_drivers(xperms, node);
601 }
602}
603
604static int cond_dup_av_list(struct cond_av_list *new,
605 struct cond_av_list *orig,
606 struct avtab *avtab)
607{
608 u32 i;
609
610 memset(new, 0, sizeof(*new));
611
612 new->nodes = kcalloc(orig->len, sizeof(*new->nodes), GFP_KERNEL);
613 if (!new->nodes)
614 return -ENOMEM;
615
616 for (i = 0; i < orig->len; i++) {
617 new->nodes[i] = avtab_insert_nonunique(avtab,
618 &orig->nodes[i]->key,
619 &orig->nodes[i]->datum);
620 if (!new->nodes[i])
621 return -ENOMEM;
622 new->len++;
623 }
624
625 return 0;
626}
627
628static int duplicate_policydb_cond_list(struct policydb *newp,
629 struct policydb *origp)
630{
631 int rc;
632 u32 i;
633
634 rc = avtab_alloc_dup(&newp->te_cond_avtab, &origp->te_cond_avtab);
635 if (rc)
636 return rc;
637
638 newp->cond_list_len = 0;
639 newp->cond_list = kcalloc(origp->cond_list_len,
640 sizeof(*newp->cond_list),
641 GFP_KERNEL);
642 if (!newp->cond_list)
643 goto error;
644
645 for (i = 0; i < origp->cond_list_len; i++) {
646 struct cond_node *newn = &newp->cond_list[i];
647 struct cond_node *orign = &origp->cond_list[i];
648
649 newp->cond_list_len++;
650
651 newn->cur_state = orign->cur_state;
652 newn->expr.nodes = kmemdup(orign->expr.nodes,
653 orign->expr.len * sizeof(*orign->expr.nodes),
654 GFP_KERNEL);
655 if (!newn->expr.nodes)
656 goto error;
657
658 newn->expr.len = orign->expr.len;
659
660 rc = cond_dup_av_list(&newn->true_list, &orign->true_list,
661 &newp->te_cond_avtab);
662 if (rc)
663 goto error;
664
665 rc = cond_dup_av_list(&newn->false_list, &orign->false_list,
666 &newp->te_cond_avtab);
667 if (rc)
668 goto error;
669 }
670
671 return 0;
672
673error:
674 avtab_destroy(&newp->te_cond_avtab);
675 cond_list_destroy(newp);
676 return -ENOMEM;
677}
678
679static int cond_bools_destroy(void *key, void *datum, void *args)
680{
681 /* key was not copied so no need to free here */
682 kfree(datum);
683 return 0;
684}
685
686static int cond_bools_copy(struct hashtab_node *new, struct hashtab_node *orig, void *args)
687{
688 struct cond_bool_datum *datum;
689
690 datum = kmemdup(orig->datum, sizeof(struct cond_bool_datum),
691 GFP_KERNEL);
692 if (!datum)
693 return -ENOMEM;
694
695 new->key = orig->key; /* No need to copy, never modified */
696 new->datum = datum;
697 return 0;
698}
699
700static int cond_bools_index(void *key, void *datum, void *args)
701{
702 struct cond_bool_datum *booldatum, **cond_bool_array;
703
704 booldatum = datum;
705 cond_bool_array = args;
706 cond_bool_array[booldatum->value - 1] = booldatum;
707
708 return 0;
709}
710
711static int duplicate_policydb_bools(struct policydb *newdb,
712 struct policydb *orig)
713{
714 struct cond_bool_datum **cond_bool_array;
715 int rc;
716
717 cond_bool_array = kmalloc_array(orig->p_bools.nprim,
718 sizeof(*orig->bool_val_to_struct),
719 GFP_KERNEL);
720 if (!cond_bool_array)
721 return -ENOMEM;
722
723 rc = hashtab_duplicate(&newdb->p_bools.table, &orig->p_bools.table,
724 cond_bools_copy, cond_bools_destroy, NULL);
725 if (rc) {
726 kfree(cond_bool_array);
727 return -ENOMEM;
728 }
729
730 hashtab_map(&newdb->p_bools.table, cond_bools_index, cond_bool_array);
731 newdb->bool_val_to_struct = cond_bool_array;
732
733 newdb->p_bools.nprim = orig->p_bools.nprim;
734
735 return 0;
736}
737
738void cond_policydb_destroy_dup(struct policydb *p)
739{
740 hashtab_map(&p->p_bools.table, cond_bools_destroy, NULL);
741 hashtab_destroy(&p->p_bools.table);
742 cond_policydb_destroy(p);
743}
744
745int cond_policydb_dup(struct policydb *new, struct policydb *orig)
746{
747 cond_policydb_init(new);
748
749 if (duplicate_policydb_bools(new, orig))
750 return -ENOMEM;
751
752 if (duplicate_policydb_cond_list(new, orig)) {
753 cond_policydb_destroy_dup(new);
754 return -ENOMEM;
755 }
756
757 return 0;
758}
1/* Authors: Karl MacMillan <kmacmillan@tresys.com>
2 * Frank Mayer <mayerf@tresys.com>
3 *
4 * Copyright (C) 2003 - 2004 Tresys Technology, LLC
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation, version 2.
8 */
9
10#include <linux/kernel.h>
11#include <linux/errno.h>
12#include <linux/string.h>
13#include <linux/spinlock.h>
14#include <linux/slab.h>
15
16#include "security.h"
17#include "conditional.h"
18#include "services.h"
19
20/*
21 * cond_evaluate_expr evaluates a conditional expr
22 * in reverse polish notation. It returns true (1), false (0),
23 * or undefined (-1). Undefined occurs when the expression
24 * exceeds the stack depth of COND_EXPR_MAXDEPTH.
25 */
26static int cond_evaluate_expr(struct policydb *p, struct cond_expr *expr)
27{
28
29 struct cond_expr *cur;
30 int s[COND_EXPR_MAXDEPTH];
31 int sp = -1;
32
33 for (cur = expr; cur; cur = cur->next) {
34 switch (cur->expr_type) {
35 case COND_BOOL:
36 if (sp == (COND_EXPR_MAXDEPTH - 1))
37 return -1;
38 sp++;
39 s[sp] = p->bool_val_to_struct[cur->bool - 1]->state;
40 break;
41 case COND_NOT:
42 if (sp < 0)
43 return -1;
44 s[sp] = !s[sp];
45 break;
46 case COND_OR:
47 if (sp < 1)
48 return -1;
49 sp--;
50 s[sp] |= s[sp + 1];
51 break;
52 case COND_AND:
53 if (sp < 1)
54 return -1;
55 sp--;
56 s[sp] &= s[sp + 1];
57 break;
58 case COND_XOR:
59 if (sp < 1)
60 return -1;
61 sp--;
62 s[sp] ^= s[sp + 1];
63 break;
64 case COND_EQ:
65 if (sp < 1)
66 return -1;
67 sp--;
68 s[sp] = (s[sp] == s[sp + 1]);
69 break;
70 case COND_NEQ:
71 if (sp < 1)
72 return -1;
73 sp--;
74 s[sp] = (s[sp] != s[sp + 1]);
75 break;
76 default:
77 return -1;
78 }
79 }
80 return s[0];
81}
82
83/*
84 * evaluate_cond_node evaluates the conditional stored in
85 * a struct cond_node and if the result is different than the
86 * current state of the node it sets the rules in the true/false
87 * list appropriately. If the result of the expression is undefined
88 * all of the rules are disabled for safety.
89 */
90int evaluate_cond_node(struct policydb *p, struct cond_node *node)
91{
92 int new_state;
93 struct cond_av_list *cur;
94
95 new_state = cond_evaluate_expr(p, node->expr);
96 if (new_state != node->cur_state) {
97 node->cur_state = new_state;
98 if (new_state == -1)
99 printk(KERN_ERR "SELinux: expression result was undefined - disabling all rules.\n");
100 /* turn the rules on or off */
101 for (cur = node->true_list; cur; cur = cur->next) {
102 if (new_state <= 0)
103 cur->node->key.specified &= ~AVTAB_ENABLED;
104 else
105 cur->node->key.specified |= AVTAB_ENABLED;
106 }
107
108 for (cur = node->false_list; cur; cur = cur->next) {
109 /* -1 or 1 */
110 if (new_state)
111 cur->node->key.specified &= ~AVTAB_ENABLED;
112 else
113 cur->node->key.specified |= AVTAB_ENABLED;
114 }
115 }
116 return 0;
117}
118
119int cond_policydb_init(struct policydb *p)
120{
121 int rc;
122
123 p->bool_val_to_struct = NULL;
124 p->cond_list = NULL;
125
126 rc = avtab_init(&p->te_cond_avtab);
127 if (rc)
128 return rc;
129
130 return 0;
131}
132
133static void cond_av_list_destroy(struct cond_av_list *list)
134{
135 struct cond_av_list *cur, *next;
136 for (cur = list; cur; cur = next) {
137 next = cur->next;
138 /* the avtab_ptr_t node is destroy by the avtab */
139 kfree(cur);
140 }
141}
142
143static void cond_node_destroy(struct cond_node *node)
144{
145 struct cond_expr *cur_expr, *next_expr;
146
147 for (cur_expr = node->expr; cur_expr; cur_expr = next_expr) {
148 next_expr = cur_expr->next;
149 kfree(cur_expr);
150 }
151 cond_av_list_destroy(node->true_list);
152 cond_av_list_destroy(node->false_list);
153 kfree(node);
154}
155
156static void cond_list_destroy(struct cond_node *list)
157{
158 struct cond_node *next, *cur;
159
160 if (list == NULL)
161 return;
162
163 for (cur = list; cur; cur = next) {
164 next = cur->next;
165 cond_node_destroy(cur);
166 }
167}
168
169void cond_policydb_destroy(struct policydb *p)
170{
171 kfree(p->bool_val_to_struct);
172 avtab_destroy(&p->te_cond_avtab);
173 cond_list_destroy(p->cond_list);
174}
175
176int cond_init_bool_indexes(struct policydb *p)
177{
178 kfree(p->bool_val_to_struct);
179 p->bool_val_to_struct = kmalloc_array(p->p_bools.nprim,
180 sizeof(*p->bool_val_to_struct),
181 GFP_KERNEL);
182 if (!p->bool_val_to_struct)
183 return -ENOMEM;
184 return 0;
185}
186
187int cond_destroy_bool(void *key, void *datum, void *p)
188{
189 kfree(key);
190 kfree(datum);
191 return 0;
192}
193
194int cond_index_bool(void *key, void *datum, void *datap)
195{
196 struct policydb *p;
197 struct cond_bool_datum *booldatum;
198 struct flex_array *fa;
199
200 booldatum = datum;
201 p = datap;
202
203 if (!booldatum->value || booldatum->value > p->p_bools.nprim)
204 return -EINVAL;
205
206 fa = p->sym_val_to_name[SYM_BOOLS];
207 if (flex_array_put_ptr(fa, booldatum->value - 1, key,
208 GFP_KERNEL | __GFP_ZERO))
209 BUG();
210 p->bool_val_to_struct[booldatum->value - 1] = booldatum;
211
212 return 0;
213}
214
215static int bool_isvalid(struct cond_bool_datum *b)
216{
217 if (!(b->state == 0 || b->state == 1))
218 return 0;
219 return 1;
220}
221
222int cond_read_bool(struct policydb *p, struct hashtab *h, void *fp)
223{
224 char *key = NULL;
225 struct cond_bool_datum *booldatum;
226 __le32 buf[3];
227 u32 len;
228 int rc;
229
230 booldatum = kzalloc(sizeof(*booldatum), GFP_KERNEL);
231 if (!booldatum)
232 return -ENOMEM;
233
234 rc = next_entry(buf, fp, sizeof buf);
235 if (rc)
236 goto err;
237
238 booldatum->value = le32_to_cpu(buf[0]);
239 booldatum->state = le32_to_cpu(buf[1]);
240
241 rc = -EINVAL;
242 if (!bool_isvalid(booldatum))
243 goto err;
244
245 len = le32_to_cpu(buf[2]);
246 if (((len == 0) || (len == (u32)-1)))
247 goto err;
248
249 rc = -ENOMEM;
250 key = kmalloc(len + 1, GFP_KERNEL);
251 if (!key)
252 goto err;
253 rc = next_entry(key, fp, len);
254 if (rc)
255 goto err;
256 key[len] = '\0';
257 rc = hashtab_insert(h, key, booldatum);
258 if (rc)
259 goto err;
260
261 return 0;
262err:
263 cond_destroy_bool(key, booldatum, NULL);
264 return rc;
265}
266
267struct cond_insertf_data {
268 struct policydb *p;
269 struct cond_av_list *other;
270 struct cond_av_list *head;
271 struct cond_av_list *tail;
272};
273
274static int cond_insertf(struct avtab *a, struct avtab_key *k, struct avtab_datum *d, void *ptr)
275{
276 struct cond_insertf_data *data = ptr;
277 struct policydb *p = data->p;
278 struct cond_av_list *other = data->other, *list, *cur;
279 struct avtab_node *node_ptr;
280 u8 found;
281 int rc = -EINVAL;
282
283 /*
284 * For type rules we have to make certain there aren't any
285 * conflicting rules by searching the te_avtab and the
286 * cond_te_avtab.
287 */
288 if (k->specified & AVTAB_TYPE) {
289 if (avtab_search(&p->te_avtab, k)) {
290 printk(KERN_ERR "SELinux: type rule already exists outside of a conditional.\n");
291 goto err;
292 }
293 /*
294 * If we are reading the false list other will be a pointer to
295 * the true list. We can have duplicate entries if there is only
296 * 1 other entry and it is in our true list.
297 *
298 * If we are reading the true list (other == NULL) there shouldn't
299 * be any other entries.
300 */
301 if (other) {
302 node_ptr = avtab_search_node(&p->te_cond_avtab, k);
303 if (node_ptr) {
304 if (avtab_search_node_next(node_ptr, k->specified)) {
305 printk(KERN_ERR "SELinux: too many conflicting type rules.\n");
306 goto err;
307 }
308 found = 0;
309 for (cur = other; cur; cur = cur->next) {
310 if (cur->node == node_ptr) {
311 found = 1;
312 break;
313 }
314 }
315 if (!found) {
316 printk(KERN_ERR "SELinux: conflicting type rules.\n");
317 goto err;
318 }
319 }
320 } else {
321 if (avtab_search(&p->te_cond_avtab, k)) {
322 printk(KERN_ERR "SELinux: conflicting type rules when adding type rule for true.\n");
323 goto err;
324 }
325 }
326 }
327
328 node_ptr = avtab_insert_nonunique(&p->te_cond_avtab, k, d);
329 if (!node_ptr) {
330 printk(KERN_ERR "SELinux: could not insert rule.\n");
331 rc = -ENOMEM;
332 goto err;
333 }
334
335 list = kzalloc(sizeof(*list), GFP_KERNEL);
336 if (!list) {
337 rc = -ENOMEM;
338 goto err;
339 }
340
341 list->node = node_ptr;
342 if (!data->head)
343 data->head = list;
344 else
345 data->tail->next = list;
346 data->tail = list;
347 return 0;
348
349err:
350 cond_av_list_destroy(data->head);
351 data->head = NULL;
352 return rc;
353}
354
355static int cond_read_av_list(struct policydb *p, void *fp, struct cond_av_list **ret_list, struct cond_av_list *other)
356{
357 int i, rc;
358 __le32 buf[1];
359 u32 len;
360 struct cond_insertf_data data;
361
362 *ret_list = NULL;
363
364 rc = next_entry(buf, fp, sizeof(u32));
365 if (rc)
366 return rc;
367
368 len = le32_to_cpu(buf[0]);
369 if (len == 0)
370 return 0;
371
372 data.p = p;
373 data.other = other;
374 data.head = NULL;
375 data.tail = NULL;
376 for (i = 0; i < len; i++) {
377 rc = avtab_read_item(&p->te_cond_avtab, fp, p, cond_insertf,
378 &data);
379 if (rc)
380 return rc;
381 }
382
383 *ret_list = data.head;
384 return 0;
385}
386
387static int expr_isvalid(struct policydb *p, struct cond_expr *expr)
388{
389 if (expr->expr_type <= 0 || expr->expr_type > COND_LAST) {
390 printk(KERN_ERR "SELinux: conditional expressions uses unknown operator.\n");
391 return 0;
392 }
393
394 if (expr->bool > p->p_bools.nprim) {
395 printk(KERN_ERR "SELinux: conditional expressions uses unknown bool.\n");
396 return 0;
397 }
398 return 1;
399}
400
401static int cond_read_node(struct policydb *p, struct cond_node *node, void *fp)
402{
403 __le32 buf[2];
404 u32 len, i;
405 int rc;
406 struct cond_expr *expr = NULL, *last = NULL;
407
408 rc = next_entry(buf, fp, sizeof(u32) * 2);
409 if (rc)
410 goto err;
411
412 node->cur_state = le32_to_cpu(buf[0]);
413
414 /* expr */
415 len = le32_to_cpu(buf[1]);
416
417 for (i = 0; i < len; i++) {
418 rc = next_entry(buf, fp, sizeof(u32) * 2);
419 if (rc)
420 goto err;
421
422 rc = -ENOMEM;
423 expr = kzalloc(sizeof(*expr), GFP_KERNEL);
424 if (!expr)
425 goto err;
426
427 expr->expr_type = le32_to_cpu(buf[0]);
428 expr->bool = le32_to_cpu(buf[1]);
429
430 if (!expr_isvalid(p, expr)) {
431 rc = -EINVAL;
432 kfree(expr);
433 goto err;
434 }
435
436 if (i == 0)
437 node->expr = expr;
438 else
439 last->next = expr;
440 last = expr;
441 }
442
443 rc = cond_read_av_list(p, fp, &node->true_list, NULL);
444 if (rc)
445 goto err;
446 rc = cond_read_av_list(p, fp, &node->false_list, node->true_list);
447 if (rc)
448 goto err;
449 return 0;
450err:
451 cond_node_destroy(node);
452 return rc;
453}
454
455int cond_read_list(struct policydb *p, void *fp)
456{
457 struct cond_node *node, *last = NULL;
458 __le32 buf[1];
459 u32 i, len;
460 int rc;
461
462 rc = next_entry(buf, fp, sizeof buf);
463 if (rc)
464 return rc;
465
466 len = le32_to_cpu(buf[0]);
467
468 rc = avtab_alloc(&(p->te_cond_avtab), p->te_avtab.nel);
469 if (rc)
470 goto err;
471
472 for (i = 0; i < len; i++) {
473 rc = -ENOMEM;
474 node = kzalloc(sizeof(*node), GFP_KERNEL);
475 if (!node)
476 goto err;
477
478 rc = cond_read_node(p, node, fp);
479 if (rc)
480 goto err;
481
482 if (i == 0)
483 p->cond_list = node;
484 else
485 last->next = node;
486 last = node;
487 }
488 return 0;
489err:
490 cond_list_destroy(p->cond_list);
491 p->cond_list = NULL;
492 return rc;
493}
494
495int cond_write_bool(void *vkey, void *datum, void *ptr)
496{
497 char *key = vkey;
498 struct cond_bool_datum *booldatum = datum;
499 struct policy_data *pd = ptr;
500 void *fp = pd->fp;
501 __le32 buf[3];
502 u32 len;
503 int rc;
504
505 len = strlen(key);
506 buf[0] = cpu_to_le32(booldatum->value);
507 buf[1] = cpu_to_le32(booldatum->state);
508 buf[2] = cpu_to_le32(len);
509 rc = put_entry(buf, sizeof(u32), 3, fp);
510 if (rc)
511 return rc;
512 rc = put_entry(key, 1, len, fp);
513 if (rc)
514 return rc;
515 return 0;
516}
517
518/*
519 * cond_write_cond_av_list doesn't write out the av_list nodes.
520 * Instead it writes out the key/value pairs from the avtab. This
521 * is necessary because there is no way to uniquely identifying rules
522 * in the avtab so it is not possible to associate individual rules
523 * in the avtab with a conditional without saving them as part of
524 * the conditional. This means that the avtab with the conditional
525 * rules will not be saved but will be rebuilt on policy load.
526 */
527static int cond_write_av_list(struct policydb *p,
528 struct cond_av_list *list, struct policy_file *fp)
529{
530 __le32 buf[1];
531 struct cond_av_list *cur_list;
532 u32 len;
533 int rc;
534
535 len = 0;
536 for (cur_list = list; cur_list != NULL; cur_list = cur_list->next)
537 len++;
538
539 buf[0] = cpu_to_le32(len);
540 rc = put_entry(buf, sizeof(u32), 1, fp);
541 if (rc)
542 return rc;
543
544 if (len == 0)
545 return 0;
546
547 for (cur_list = list; cur_list != NULL; cur_list = cur_list->next) {
548 rc = avtab_write_item(p, cur_list->node, fp);
549 if (rc)
550 return rc;
551 }
552
553 return 0;
554}
555
556static int cond_write_node(struct policydb *p, struct cond_node *node,
557 struct policy_file *fp)
558{
559 struct cond_expr *cur_expr;
560 __le32 buf[2];
561 int rc;
562 u32 len = 0;
563
564 buf[0] = cpu_to_le32(node->cur_state);
565 rc = put_entry(buf, sizeof(u32), 1, fp);
566 if (rc)
567 return rc;
568
569 for (cur_expr = node->expr; cur_expr != NULL; cur_expr = cur_expr->next)
570 len++;
571
572 buf[0] = cpu_to_le32(len);
573 rc = put_entry(buf, sizeof(u32), 1, fp);
574 if (rc)
575 return rc;
576
577 for (cur_expr = node->expr; cur_expr != NULL; cur_expr = cur_expr->next) {
578 buf[0] = cpu_to_le32(cur_expr->expr_type);
579 buf[1] = cpu_to_le32(cur_expr->bool);
580 rc = put_entry(buf, sizeof(u32), 2, fp);
581 if (rc)
582 return rc;
583 }
584
585 rc = cond_write_av_list(p, node->true_list, fp);
586 if (rc)
587 return rc;
588 rc = cond_write_av_list(p, node->false_list, fp);
589 if (rc)
590 return rc;
591
592 return 0;
593}
594
595int cond_write_list(struct policydb *p, struct cond_node *list, void *fp)
596{
597 struct cond_node *cur;
598 u32 len;
599 __le32 buf[1];
600 int rc;
601
602 len = 0;
603 for (cur = list; cur != NULL; cur = cur->next)
604 len++;
605 buf[0] = cpu_to_le32(len);
606 rc = put_entry(buf, sizeof(u32), 1, fp);
607 if (rc)
608 return rc;
609
610 for (cur = list; cur != NULL; cur = cur->next) {
611 rc = cond_write_node(p, cur, fp);
612 if (rc)
613 return rc;
614 }
615
616 return 0;
617}
618
619void cond_compute_xperms(struct avtab *ctab, struct avtab_key *key,
620 struct extended_perms_decision *xpermd)
621{
622 struct avtab_node *node;
623
624 if (!ctab || !key || !xpermd)
625 return;
626
627 for (node = avtab_search_node(ctab, key); node;
628 node = avtab_search_node_next(node, key->specified)) {
629 if (node->key.specified & AVTAB_ENABLED)
630 services_compute_xperms_decision(xpermd, node);
631 }
632 return;
633
634}
635/* Determine whether additional permissions are granted by the conditional
636 * av table, and if so, add them to the result
637 */
638void cond_compute_av(struct avtab *ctab, struct avtab_key *key,
639 struct av_decision *avd, struct extended_perms *xperms)
640{
641 struct avtab_node *node;
642
643 if (!ctab || !key || !avd)
644 return;
645
646 for (node = avtab_search_node(ctab, key); node;
647 node = avtab_search_node_next(node, key->specified)) {
648 if ((u16)(AVTAB_ALLOWED|AVTAB_ENABLED) ==
649 (node->key.specified & (AVTAB_ALLOWED|AVTAB_ENABLED)))
650 avd->allowed |= node->datum.u.data;
651 if ((u16)(AVTAB_AUDITDENY|AVTAB_ENABLED) ==
652 (node->key.specified & (AVTAB_AUDITDENY|AVTAB_ENABLED)))
653 /* Since a '0' in an auditdeny mask represents a
654 * permission we do NOT want to audit (dontaudit), we use
655 * the '&' operand to ensure that all '0's in the mask
656 * are retained (much unlike the allow and auditallow cases).
657 */
658 avd->auditdeny &= node->datum.u.data;
659 if ((u16)(AVTAB_AUDITALLOW|AVTAB_ENABLED) ==
660 (node->key.specified & (AVTAB_AUDITALLOW|AVTAB_ENABLED)))
661 avd->auditallow |= node->datum.u.data;
662 if (xperms && (node->key.specified & AVTAB_ENABLED) &&
663 (node->key.specified & AVTAB_XPERMS))
664 services_compute_xperms_drivers(xperms, node);
665 }
666}