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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}
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}