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 "SELinux: 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) {
103 cur->node->key.specified &= ~AVTAB_ENABLED;
105 cur->node->key.specified |= AVTAB_ENABLED;
108 for (cur = node->false_list; cur != NULL; cur = cur->next) {
111 cur->node->key.specified &= ~AVTAB_ENABLED;
113 cur->node->key.specified |= AVTAB_ENABLED;
119 int cond_policydb_init(struct policydb *p)
121 p->bool_val_to_struct = NULL;
123 if (avtab_init(&p->te_cond_avtab))
129 static void cond_av_list_destroy(struct cond_av_list *list)
131 struct cond_av_list *cur, *next;
132 for (cur = list; cur != NULL; cur = next) {
134 /* the avtab_ptr_t node is destroy by the avtab */
139 static void cond_node_destroy(struct cond_node *node)
141 struct cond_expr *cur_expr, *next_expr;
143 for (cur_expr = node->expr; cur_expr != NULL; cur_expr = next_expr) {
144 next_expr = cur_expr->next;
147 cond_av_list_destroy(node->true_list);
148 cond_av_list_destroy(node->false_list);
152 static void cond_list_destroy(struct cond_node *list)
154 struct cond_node *next, *cur;
159 for (cur = list; cur != NULL; cur = next) {
161 cond_node_destroy(cur);
165 void cond_policydb_destroy(struct policydb *p)
167 kfree(p->bool_val_to_struct);
168 avtab_destroy(&p->te_cond_avtab);
169 cond_list_destroy(p->cond_list);
172 int cond_init_bool_indexes(struct policydb *p)
174 kfree(p->bool_val_to_struct);
175 p->bool_val_to_struct = (struct cond_bool_datum **)
176 kmalloc(p->p_bools.nprim * sizeof(struct cond_bool_datum *), GFP_KERNEL);
177 if (!p->bool_val_to_struct)
182 int cond_destroy_bool(void *key, void *datum, void *p)
189 int cond_index_bool(void *key, void *datum, void *datap)
192 struct cond_bool_datum *booldatum;
197 if (!booldatum->value || booldatum->value > p->p_bools.nprim)
200 p->p_bool_val_to_name[booldatum->value - 1] = key;
201 p->bool_val_to_struct[booldatum->value - 1] = booldatum;
206 static int bool_isvalid(struct cond_bool_datum *b)
208 if (!(b->state == 0 || b->state == 1))
213 int cond_read_bool(struct policydb *p, struct hashtab *h, void *fp)
216 struct cond_bool_datum *booldatum;
221 booldatum = kzalloc(sizeof(struct cond_bool_datum), GFP_KERNEL);
225 rc = next_entry(buf, fp, sizeof buf);
229 booldatum->value = le32_to_cpu(buf[0]);
230 booldatum->state = le32_to_cpu(buf[1]);
232 if (!bool_isvalid(booldatum))
235 len = le32_to_cpu(buf[2]);
237 key = kmalloc(len + 1, GFP_KERNEL);
240 rc = next_entry(key, fp, len);
244 if (hashtab_insert(h, key, booldatum))
249 cond_destroy_bool(key, booldatum, NULL);
253 struct cond_insertf_data {
255 struct cond_av_list *other;
256 struct cond_av_list *head;
257 struct cond_av_list *tail;
260 static int cond_insertf(struct avtab *a, struct avtab_key *k, struct avtab_datum *d, void *ptr)
262 struct cond_insertf_data *data = ptr;
263 struct policydb *p = data->p;
264 struct cond_av_list *other = data->other, *list, *cur;
265 struct avtab_node *node_ptr;
270 * For type rules we have to make certain there aren't any
271 * conflicting rules by searching the te_avtab and the
274 if (k->specified & AVTAB_TYPE) {
275 if (avtab_search(&p->te_avtab, k)) {
276 printk("SELinux: type rule already exists outside of a conditional.");
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.
284 * If we are reading the true list (other == NULL) there shouldn't
285 * be any other entries.
288 node_ptr = avtab_search_node(&p->te_cond_avtab, k);
290 if (avtab_search_node_next(node_ptr, k->specified)) {
291 printk("SELinux: too many conflicting type rules.");
295 for (cur = other; cur != NULL; cur = cur->next) {
296 if (cur->node == node_ptr) {
302 printk("SELinux: conflicting type rules.\n");
307 if (avtab_search(&p->te_cond_avtab, k)) {
308 printk("SELinux: conflicting type rules when adding type rule for true.\n");
314 node_ptr = avtab_insert_nonunique(&p->te_cond_avtab, k, d);
316 printk("SELinux: could not insert rule.");
320 list = kzalloc(sizeof(struct cond_av_list), GFP_KERNEL);
324 list->node = node_ptr;
328 data->tail->next = list;
333 cond_av_list_destroy(data->head);
338 static int cond_read_av_list(struct policydb *p, void *fp, struct cond_av_list **ret_list, struct cond_av_list *other)
343 struct cond_insertf_data data;
348 rc = next_entry(buf, fp, sizeof(u32));
352 len = le32_to_cpu(buf[0]);
360 for (i = 0; i < len; i++) {
361 rc = avtab_read_item(&p->te_cond_avtab, fp, p, cond_insertf,
368 *ret_list = data.head;
372 static int expr_isvalid(struct policydb *p, struct cond_expr *expr)
374 if (expr->expr_type <= 0 || expr->expr_type > COND_LAST) {
375 printk("SELinux: conditional expressions uses unknown operator.\n");
379 if (expr->bool > p->p_bools.nprim) {
380 printk("SELinux: conditional expressions uses unknown bool.\n");
386 static int cond_read_node(struct policydb *p, struct cond_node *node, void *fp)
391 struct cond_expr *expr = NULL, *last = NULL;
393 rc = next_entry(buf, fp, sizeof(u32));
397 node->cur_state = le32_to_cpu(buf[0]);
400 rc = next_entry(buf, fp, sizeof(u32));
405 len = le32_to_cpu(buf[0]);
407 for (i = 0; i < len; i++) {
408 rc = next_entry(buf, fp, sizeof(u32) * 2);
412 expr = kzalloc(sizeof(struct cond_expr), GFP_KERNEL);
416 expr->expr_type = le32_to_cpu(buf[0]);
417 expr->bool = le32_to_cpu(buf[1]);
419 if (!expr_isvalid(p, expr)) {
431 if (cond_read_av_list(p, fp, &node->true_list, NULL) != 0)
433 if (cond_read_av_list(p, fp, &node->false_list, node->true_list) != 0)
437 cond_node_destroy(node);
441 int cond_read_list(struct policydb *p, void *fp)
443 struct cond_node *node, *last = NULL;
448 rc = next_entry(buf, fp, sizeof buf);
452 len = le32_to_cpu(buf[0]);
454 rc = avtab_alloc(&(p->te_cond_avtab), p->te_avtab.nel);
458 for (i = 0; i < len; i++) {
459 node = kzalloc(sizeof(struct cond_node), GFP_KERNEL);
463 if (cond_read_node(p, node, fp) != 0)
474 cond_list_destroy(p->cond_list);
479 /* Determine whether additional permissions are granted by the conditional
480 * av table, and if so, add them to the result
482 void cond_compute_av(struct avtab *ctab, struct avtab_key *key, struct av_decision *avd)
484 struct avtab_node *node;
486 if (!ctab || !key || !avd)
489 for (node = avtab_search_node(ctab, key); node != NULL;
490 node = avtab_search_node_next(node, key->specified)) {
491 if ((u16)(AVTAB_ALLOWED|AVTAB_ENABLED) ==
492 (node->key.specified & (AVTAB_ALLOWED|AVTAB_ENABLED)))
493 avd->allowed |= node->datum.data;
494 if ((u16)(AVTAB_AUDITDENY|AVTAB_ENABLED) ==
495 (node->key.specified & (AVTAB_AUDITDENY|AVTAB_ENABLED)))
496 /* Since a '0' in an auditdeny mask represents a
497 * permission we do NOT want to audit (dontaudit), we use
498 * the '&' operand to ensure that all '0's in the mask
499 * are retained (much unlike the allow and auditallow cases).
501 avd->auditdeny &= node->datum.data;
502 if ((u16)(AVTAB_AUDITALLOW|AVTAB_ENABLED) ==
503 (node->key.specified & (AVTAB_AUDITALLOW|AVTAB_ENABLED)))
504 avd->auditallow |= node->datum.data;