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