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