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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:20:36 -0400
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /security/selinux/ss/conditional.c
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
Diffstat (limited to 'security/selinux/ss/conditional.c')
-rw-r--r--security/selinux/ss/conditional.c489
1 files changed, 489 insertions, 0 deletions
diff --git a/security/selinux/ss/conditional.c b/security/selinux/ss/conditional.c
new file mode 100644
index 000000000000..b53441184aca
--- /dev/null
+++ b/security/selinux/ss/conditional.c
@@ -0,0 +1,489 @@
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 <asm/semaphore.h>
15#include <linux/slab.h>
16
17#include "security.h"
18#include "conditional.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 != NULL; 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 "security: expression result was undefined - disabling all rules.\n");
100 /* turn the rules on or off */
101 for (cur = node->true_list; cur != NULL; cur = cur->next) {
102 if (new_state <= 0) {
103 cur->node->datum.specified &= ~AVTAB_ENABLED;
104 } else {
105 cur->node->datum.specified |= AVTAB_ENABLED;
106 }
107 }
108
109 for (cur = node->false_list; cur != NULL; cur = cur->next) {
110 /* -1 or 1 */
111 if (new_state) {
112 cur->node->datum.specified &= ~AVTAB_ENABLED;
113 } else {
114 cur->node->datum.specified |= AVTAB_ENABLED;
115 }
116 }
117 }
118 return 0;
119}
120
121int cond_policydb_init(struct policydb *p)
122{
123 p->bool_val_to_struct = NULL;
124 p->cond_list = NULL;
125 if (avtab_init(&p->te_cond_avtab))
126 return -1;
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 != NULL; 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 != NULL; 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 != NULL; cur = next) {
162 next = cur->next;
163 cond_node_destroy(cur);
164 }
165}
166
167void cond_policydb_destroy(struct policydb *p)
168{
169 if (p->bool_val_to_struct != NULL)
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 if (p->bool_val_to_struct)
178 kfree(p->bool_val_to_struct);
179 p->bool_val_to_struct = (struct cond_bool_datum**)
180 kmalloc(p->p_bools.nprim * sizeof(struct cond_bool_datum*), GFP_KERNEL);
181 if (!p->bool_val_to_struct)
182 return -1;
183 return 0;
184}
185
186int cond_destroy_bool(void *key, void *datum, void *p)
187{
188 if (key)
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
199 booldatum = datum;
200 p = datap;
201
202 if (!booldatum->value || booldatum->value > p->p_bools.nprim)
203 return -EINVAL;
204
205 p->p_bool_val_to_name[booldatum->value - 1] = key;
206 p->bool_val_to_struct[booldatum->value -1] = booldatum;
207
208 return 0;
209}
210
211static int bool_isvalid(struct cond_bool_datum *b)
212{
213 if (!(b->state == 0 || b->state == 1))
214 return 0;
215 return 1;
216}
217
218int cond_read_bool(struct policydb *p, struct hashtab *h, void *fp)
219{
220 char *key = NULL;
221 struct cond_bool_datum *booldatum;
222 u32 buf[3], len;
223 int rc;
224
225 booldatum = kmalloc(sizeof(struct cond_bool_datum), GFP_KERNEL);
226 if (!booldatum)
227 return -1;
228 memset(booldatum, 0, sizeof(struct cond_bool_datum));
229
230 rc = next_entry(buf, fp, sizeof buf);
231 if (rc < 0)
232 goto err;
233
234 booldatum->value = le32_to_cpu(buf[0]);
235 booldatum->state = le32_to_cpu(buf[1]);
236
237 if (!bool_isvalid(booldatum))
238 goto err;
239
240 len = le32_to_cpu(buf[2]);
241
242 key = kmalloc(len + 1, GFP_KERNEL);
243 if (!key)
244 goto err;
245 rc = next_entry(key, fp, len);
246 if (rc < 0)
247 goto err;
248 key[len] = 0;
249 if (hashtab_insert(h, key, booldatum))
250 goto err;
251
252 return 0;
253err:
254 cond_destroy_bool(key, booldatum, NULL);
255 return -1;
256}
257
258static int cond_read_av_list(struct policydb *p, void *fp, struct cond_av_list **ret_list,
259 struct cond_av_list *other)
260{
261 struct cond_av_list *list, *last = NULL, *cur;
262 struct avtab_key key;
263 struct avtab_datum datum;
264 struct avtab_node *node_ptr;
265 int rc;
266 u32 buf[1], i, len;
267 u8 found;
268
269 *ret_list = NULL;
270
271 len = 0;
272 rc = next_entry(buf, fp, sizeof buf);
273 if (rc < 0)
274 return -1;
275
276 len = le32_to_cpu(buf[0]);
277 if (len == 0) {
278 return 0;
279 }
280
281 for (i = 0; i < len; i++) {
282 if (avtab_read_item(fp, &datum, &key))
283 goto err;
284
285 /*
286 * For type rules we have to make certain there aren't any
287 * conflicting rules by searching the te_avtab and the
288 * cond_te_avtab.
289 */
290 if (datum.specified & AVTAB_TYPE) {
291 if (avtab_search(&p->te_avtab, &key, AVTAB_TYPE)) {
292 printk("security: type rule already exists outside of a conditional.");
293 goto err;
294 }
295 /*
296 * If we are reading the false list other will be a pointer to
297 * the true list. We can have duplicate entries if there is only
298 * 1 other entry and it is in our true list.
299 *
300 * If we are reading the true list (other == NULL) there shouldn't
301 * be any other entries.
302 */
303 if (other) {
304 node_ptr = avtab_search_node(&p->te_cond_avtab, &key, AVTAB_TYPE);
305 if (node_ptr) {
306 if (avtab_search_node_next(node_ptr, AVTAB_TYPE)) {
307 printk("security: too many conflicting type rules.");
308 goto err;
309 }
310 found = 0;
311 for (cur = other; cur != NULL; cur = cur->next) {
312 if (cur->node == node_ptr) {
313 found = 1;
314 break;
315 }
316 }
317 if (!found) {
318 printk("security: conflicting type rules.");
319 goto err;
320 }
321 }
322 } else {
323 if (avtab_search(&p->te_cond_avtab, &key, AVTAB_TYPE)) {
324 printk("security: conflicting type rules when adding type rule for true.");
325 goto err;
326 }
327 }
328 }
329 node_ptr = avtab_insert_nonunique(&p->te_cond_avtab, &key, &datum);
330 if (!node_ptr) {
331 printk("security: could not insert rule.");
332 goto err;
333 }
334
335 list = kmalloc(sizeof(struct cond_av_list), GFP_KERNEL);
336 if (!list)
337 goto err;
338 memset(list, 0, sizeof(struct cond_av_list));
339
340 list->node = node_ptr;
341 if (i == 0)
342 *ret_list = list;
343 else
344 last->next = list;
345 last = list;
346
347 }
348
349 return 0;
350err:
351 cond_av_list_destroy(*ret_list);
352 *ret_list = NULL;
353 return -1;
354}
355
356static int expr_isvalid(struct policydb *p, struct cond_expr *expr)
357{
358 if (expr->expr_type <= 0 || expr->expr_type > COND_LAST) {
359 printk("security: conditional expressions uses unknown operator.\n");
360 return 0;
361 }
362
363 if (expr->bool > p->p_bools.nprim) {
364 printk("security: conditional expressions uses unknown bool.\n");
365 return 0;
366 }
367 return 1;
368}
369
370static int cond_read_node(struct policydb *p, struct cond_node *node, void *fp)
371{
372 u32 buf[2], len, i;
373 int rc;
374 struct cond_expr *expr = NULL, *last = NULL;
375
376 rc = next_entry(buf, fp, sizeof(u32));
377 if (rc < 0)
378 return -1;
379
380 node->cur_state = le32_to_cpu(buf[0]);
381
382 len = 0;
383 rc = next_entry(buf, fp, sizeof(u32));
384 if (rc < 0)
385 return -1;
386
387 /* expr */
388 len = le32_to_cpu(buf[0]);
389
390 for (i = 0; i < len; i++ ) {
391 rc = next_entry(buf, fp, sizeof(u32) * 2);
392 if (rc < 0)
393 goto err;
394
395 expr = kmalloc(sizeof(struct cond_expr), GFP_KERNEL);
396 if (!expr) {
397 goto err;
398 }
399 memset(expr, 0, sizeof(struct cond_expr));
400
401 expr->expr_type = le32_to_cpu(buf[0]);
402 expr->bool = le32_to_cpu(buf[1]);
403
404 if (!expr_isvalid(p, expr)) {
405 kfree(expr);
406 goto err;
407 }
408
409 if (i == 0) {
410 node->expr = expr;
411 } else {
412 last->next = expr;
413 }
414 last = expr;
415 }
416
417 if (cond_read_av_list(p, fp, &node->true_list, NULL) != 0)
418 goto err;
419 if (cond_read_av_list(p, fp, &node->false_list, node->true_list) != 0)
420 goto err;
421 return 0;
422err:
423 cond_node_destroy(node);
424 return -1;
425}
426
427int cond_read_list(struct policydb *p, void *fp)
428{
429 struct cond_node *node, *last = NULL;
430 u32 buf[1], i, len;
431 int rc;
432
433 rc = next_entry(buf, fp, sizeof buf);
434 if (rc < 0)
435 return -1;
436
437 len = le32_to_cpu(buf[0]);
438
439 for (i = 0; i < len; i++) {
440 node = kmalloc(sizeof(struct cond_node), GFP_KERNEL);
441 if (!node)
442 goto err;
443 memset(node, 0, sizeof(struct cond_node));
444
445 if (cond_read_node(p, node, fp) != 0)
446 goto err;
447
448 if (i == 0) {
449 p->cond_list = node;
450 } else {
451 last->next = node;
452 }
453 last = node;
454 }
455 return 0;
456err:
457 cond_list_destroy(p->cond_list);
458 return -1;
459}
460
461/* Determine whether additional permissions are granted by the conditional
462 * av table, and if so, add them to the result
463 */
464void cond_compute_av(struct avtab *ctab, struct avtab_key *key, struct av_decision *avd)
465{
466 struct avtab_node *node;
467
468 if(!ctab || !key || !avd)
469 return;
470
471 for(node = avtab_search_node(ctab, key, AVTAB_AV); node != NULL;
472 node = avtab_search_node_next(node, AVTAB_AV)) {
473 if ( (__u32) (AVTAB_ALLOWED|AVTAB_ENABLED) ==
474 (node->datum.specified & (AVTAB_ALLOWED|AVTAB_ENABLED)))
475 avd->allowed |= avtab_allowed(&node->datum);
476 if ( (__u32) (AVTAB_AUDITDENY|AVTAB_ENABLED) ==
477 (node->datum.specified & (AVTAB_AUDITDENY|AVTAB_ENABLED)))
478 /* Since a '0' in an auditdeny mask represents a
479 * permission we do NOT want to audit (dontaudit), we use
480 * the '&' operand to ensure that all '0's in the mask
481 * are retained (much unlike the allow and auditallow cases).
482 */
483 avd->auditdeny &= avtab_auditdeny(&node->datum);
484 if ( (__u32) (AVTAB_AUDITALLOW|AVTAB_ENABLED) ==
485 (node->datum.specified & (AVTAB_AUDITALLOW|AVTAB_ENABLED)))
486 avd->auditallow |= avtab_auditallow(&node->datum);
487 }
488 return;
489}