1 /* Authors: Karl MacMillan <kmacmillan@tresys.com>
2 * Frank Mayer <mayerf@tresys.com>
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.
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>
18 #include "conditional.h"
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.
26 static int cond_evaluate_expr(struct policydb *p, struct cond_expr *expr)
29 struct cond_expr *cur;
30 int s[COND_EXPR_MAXDEPTH];
33 for (cur = expr; cur != NULL; cur = cur->next) {
34 switch (cur->expr_type) {
36 if (sp == (COND_EXPR_MAXDEPTH - 1))
39 s[sp] = p->bool_val_to_struct[cur->bool - 1]->state;
68 s[sp] = (s[sp] == s[sp + 1]);
74 s[sp] = (s[sp] != s[sp + 1]);
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.
90 int evaluate_cond_node(struct policydb *p, struct cond_node *node)
93 struct cond_av_list* cur;
95 new_state = cond_evaluate_expr(p, node->expr);
96 if (new_state != node->cur_state) {
97 node->cur_state = new_state;
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;
105 cur->node->datum.specified |= AVTAB_ENABLED;
109 for (cur = node->false_list; cur != NULL; cur = cur->next) {
112 cur->node->datum.specified &= ~AVTAB_ENABLED;
114 cur->node->datum.specified |= AVTAB_ENABLED;
121 int cond_policydb_init(struct policydb *p)
123 p->bool_val_to_struct = NULL;
125 if (avtab_init(&p->te_cond_avtab))
131 static void cond_av_list_destroy(struct cond_av_list *list)
133 struct cond_av_list *cur, *next;
134 for (cur = list; cur != NULL; cur = next) {
136 /* the avtab_ptr_t node is destroy by the avtab */
141 static void cond_node_destroy(struct cond_node *node)
143 struct cond_expr *cur_expr, *next_expr;
145 for (cur_expr = node->expr; cur_expr != NULL; cur_expr = next_expr) {
146 next_expr = cur_expr->next;
149 cond_av_list_destroy(node->true_list);
150 cond_av_list_destroy(node->false_list);
154 static void cond_list_destroy(struct cond_node *list)
156 struct cond_node *next, *cur;
161 for (cur = list; cur != NULL; cur = next) {
163 cond_node_destroy(cur);
167 void cond_policydb_destroy(struct policydb *p)
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);
175 int cond_init_bool_indexes(struct policydb *p)
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)
186 int cond_destroy_bool(void *key, void *datum, void *p)
194 int cond_index_bool(void *key, void *datum, void *datap)
197 struct cond_bool_datum *booldatum;
202 if (!booldatum->value || booldatum->value > p->p_bools.nprim)
205 p->p_bool_val_to_name[booldatum->value - 1] = key;
206 p->bool_val_to_struct[booldatum->value -1] = booldatum;
211 static int bool_isvalid(struct cond_bool_datum *b)
213 if (!(b->state == 0 || b->state == 1))
218 int cond_read_bool(struct policydb *p, struct hashtab *h, void *fp)
221 struct cond_bool_datum *booldatum;
225 booldatum = kmalloc(sizeof(struct cond_bool_datum), GFP_KERNEL);
228 memset(booldatum, 0, sizeof(struct cond_bool_datum));
230 rc = next_entry(buf, fp, sizeof buf);
234 booldatum->value = le32_to_cpu(buf[0]);
235 booldatum->state = le32_to_cpu(buf[1]);
237 if (!bool_isvalid(booldatum))
240 len = le32_to_cpu(buf[2]);
242 key = kmalloc(len + 1, GFP_KERNEL);
245 rc = next_entry(key, fp, len);
249 if (hashtab_insert(h, key, booldatum))
254 cond_destroy_bool(key, booldatum, NULL);
258 static int cond_read_av_list(struct policydb *p, void *fp, struct cond_av_list **ret_list,
259 struct cond_av_list *other)
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;
272 rc = next_entry(buf, fp, sizeof buf);
276 len = le32_to_cpu(buf[0]);
281 for (i = 0; i < len; i++) {
282 if (avtab_read_item(fp, &datum, &key))
286 * For type rules we have to make certain there aren't any
287 * conflicting rules by searching the te_avtab and the
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.");
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.
300 * If we are reading the true list (other == NULL) there shouldn't
301 * be any other entries.
304 node_ptr = avtab_search_node(&p->te_cond_avtab, &key, AVTAB_TYPE);
306 if (avtab_search_node_next(node_ptr, AVTAB_TYPE)) {
307 printk("security: too many conflicting type rules.");
311 for (cur = other; cur != NULL; cur = cur->next) {
312 if (cur->node == node_ptr) {
318 printk("security: conflicting type rules.");
323 if (avtab_search(&p->te_cond_avtab, &key, AVTAB_TYPE)) {
324 printk("security: conflicting type rules when adding type rule for true.");
329 node_ptr = avtab_insert_nonunique(&p->te_cond_avtab, &key, &datum);
331 printk("security: could not insert rule.");
335 list = kmalloc(sizeof(struct cond_av_list), GFP_KERNEL);
338 memset(list, 0, sizeof(struct cond_av_list));
340 list->node = node_ptr;
351 cond_av_list_destroy(*ret_list);
356 static int expr_isvalid(struct policydb *p, struct cond_expr *expr)
358 if (expr->expr_type <= 0 || expr->expr_type > COND_LAST) {
359 printk("security: conditional expressions uses unknown operator.\n");
363 if (expr->bool > p->p_bools.nprim) {
364 printk("security: conditional expressions uses unknown bool.\n");
370 static int cond_read_node(struct policydb *p, struct cond_node *node, void *fp)
374 struct cond_expr *expr = NULL, *last = NULL;
376 rc = next_entry(buf, fp, sizeof(u32));
380 node->cur_state = le32_to_cpu(buf[0]);
383 rc = next_entry(buf, fp, sizeof(u32));
388 len = le32_to_cpu(buf[0]);
390 for (i = 0; i < len; i++ ) {
391 rc = next_entry(buf, fp, sizeof(u32) * 2);
395 expr = kmalloc(sizeof(struct cond_expr), GFP_KERNEL);
399 memset(expr, 0, sizeof(struct cond_expr));
401 expr->expr_type = le32_to_cpu(buf[0]);
402 expr->bool = le32_to_cpu(buf[1]);
404 if (!expr_isvalid(p, expr)) {
417 if (cond_read_av_list(p, fp, &node->true_list, NULL) != 0)
419 if (cond_read_av_list(p, fp, &node->false_list, node->true_list) != 0)
423 cond_node_destroy(node);
427 int cond_read_list(struct policydb *p, void *fp)
429 struct cond_node *node, *last = NULL;
433 rc = next_entry(buf, fp, sizeof buf);
437 len = le32_to_cpu(buf[0]);
439 for (i = 0; i < len; i++) {
440 node = kmalloc(sizeof(struct cond_node), GFP_KERNEL);
443 memset(node, 0, sizeof(struct cond_node));
445 if (cond_read_node(p, node, fp) != 0)
457 cond_list_destroy(p->cond_list);
461 /* Determine whether additional permissions are granted by the conditional
462 * av table, and if so, add them to the result
464 void cond_compute_av(struct avtab *ctab, struct avtab_key *key, struct av_decision *avd)
466 struct avtab_node *node;
468 if(!ctab || !key || !avd)
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).
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);