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