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 <linux/slab.h>
17 #include "conditional.h"
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.
25 static int cond_evaluate_expr(struct policydb *p, struct cond_expr *expr)
28 struct cond_expr *cur;
29 int s[COND_EXPR_MAXDEPTH];
32 for (cur = expr; cur; cur = cur->next) {
33 switch (cur->expr_type) {
35 if (sp == (COND_EXPR_MAXDEPTH - 1))
38 s[sp] = p->bool_val_to_struct[cur->bool - 1]->state;
67 s[sp] = (s[sp] == s[sp + 1]);
73 s[sp] = (s[sp] != s[sp + 1]);
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.
89 int evaluate_cond_node(struct policydb *p, struct cond_node *node)
92 struct cond_av_list *cur;
94 new_state = cond_evaluate_expr(p, node->expr);
95 if (new_state != node->cur_state) {
96 node->cur_state = new_state;
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) {
102 cur->node->key.specified &= ~AVTAB_ENABLED;
104 cur->node->key.specified |= AVTAB_ENABLED;
107 for (cur = node->false_list; cur; cur = cur->next) {
110 cur->node->key.specified &= ~AVTAB_ENABLED;
112 cur->node->key.specified |= AVTAB_ENABLED;
118 int cond_policydb_init(struct policydb *p)
120 p->bool_val_to_struct = NULL;
122 if (avtab_init(&p->te_cond_avtab))
128 static void cond_av_list_destroy(struct cond_av_list *list)
130 struct cond_av_list *cur, *next;
131 for (cur = list; cur; cur = next) {
133 /* the avtab_ptr_t node is destroy by the avtab */
138 static void cond_node_destroy(struct cond_node *node)
140 struct cond_expr *cur_expr, *next_expr;
142 for (cur_expr = node->expr; cur_expr; cur_expr = next_expr) {
143 next_expr = cur_expr->next;
146 cond_av_list_destroy(node->true_list);
147 cond_av_list_destroy(node->false_list);
151 static void cond_list_destroy(struct cond_node *list)
153 struct cond_node *next, *cur;
158 for (cur = list; cur; cur = next) {
160 cond_node_destroy(cur);
164 void cond_policydb_destroy(struct policydb *p)
166 kfree(p->bool_val_to_struct);
167 avtab_destroy(&p->te_cond_avtab);
168 cond_list_destroy(p->cond_list);
171 int cond_init_bool_indexes(struct policydb *p)
173 kfree(p->bool_val_to_struct);
174 p->bool_val_to_struct = (struct cond_bool_datum **)
175 kmalloc(p->p_bools.nprim * sizeof(struct cond_bool_datum *), GFP_KERNEL);
176 if (!p->bool_val_to_struct)
181 int cond_destroy_bool(void *key, void *datum, void *p)
188 int cond_index_bool(void *key, void *datum, void *datap)
191 struct cond_bool_datum *booldatum;
196 if (!booldatum->value || booldatum->value > p->p_bools.nprim)
199 p->p_bool_val_to_name[booldatum->value - 1] = key;
200 p->bool_val_to_struct[booldatum->value - 1] = booldatum;
205 static int bool_isvalid(struct cond_bool_datum *b)
207 if (!(b->state == 0 || b->state == 1))
212 int cond_read_bool(struct policydb *p, struct hashtab *h, void *fp)
215 struct cond_bool_datum *booldatum;
220 booldatum = kzalloc(sizeof(struct cond_bool_datum), GFP_KERNEL);
224 rc = next_entry(buf, fp, sizeof buf);
228 booldatum->value = le32_to_cpu(buf[0]);
229 booldatum->state = le32_to_cpu(buf[1]);
231 if (!bool_isvalid(booldatum))
234 len = le32_to_cpu(buf[2]);
236 key = kmalloc(len + 1, GFP_KERNEL);
239 rc = next_entry(key, fp, len);
243 if (hashtab_insert(h, key, booldatum))
248 cond_destroy_bool(key, booldatum, NULL);
252 struct cond_insertf_data {
254 struct cond_av_list *other;
255 struct cond_av_list *head;
256 struct cond_av_list *tail;
259 static int cond_insertf(struct avtab *a, struct avtab_key *k, struct avtab_datum *d, void *ptr)
261 struct cond_insertf_data *data = ptr;
262 struct policydb *p = data->p;
263 struct cond_av_list *other = data->other, *list, *cur;
264 struct avtab_node *node_ptr;
269 * For type rules we have to make certain there aren't any
270 * conflicting rules by searching the te_avtab and the
273 if (k->specified & AVTAB_TYPE) {
274 if (avtab_search(&p->te_avtab, k)) {
275 printk(KERN_ERR "SELinux: type rule already exists outside of a conditional.\n");
279 * If we are reading the false list other will be a pointer to
280 * the true list. We can have duplicate entries if there is only
281 * 1 other entry and it is in our true list.
283 * If we are reading the true list (other == NULL) there shouldn't
284 * be any other entries.
287 node_ptr = avtab_search_node(&p->te_cond_avtab, k);
289 if (avtab_search_node_next(node_ptr, k->specified)) {
290 printk(KERN_ERR "SELinux: too many conflicting type rules.\n");
294 for (cur = other; cur; cur = cur->next) {
295 if (cur->node == node_ptr) {
301 printk(KERN_ERR "SELinux: conflicting type rules.\n");
306 if (avtab_search(&p->te_cond_avtab, k)) {
307 printk(KERN_ERR "SELinux: conflicting type rules when adding type rule for true.\n");
313 node_ptr = avtab_insert_nonunique(&p->te_cond_avtab, k, d);
315 printk(KERN_ERR "SELinux: could not insert rule.\n");
320 list = kzalloc(sizeof(struct cond_av_list), GFP_KERNEL);
326 list->node = node_ptr;
330 data->tail->next = list;
335 cond_av_list_destroy(data->head);
340 static int cond_read_av_list(struct policydb *p, void *fp, struct cond_av_list **ret_list, struct cond_av_list *other)
345 struct cond_insertf_data data;
350 rc = next_entry(buf, fp, sizeof(u32));
354 len = le32_to_cpu(buf[0]);
362 for (i = 0; i < len; i++) {
363 rc = avtab_read_item(&p->te_cond_avtab, fp, p, cond_insertf,
369 *ret_list = data.head;
373 static int expr_isvalid(struct policydb *p, struct cond_expr *expr)
375 if (expr->expr_type <= 0 || expr->expr_type > COND_LAST) {
376 printk(KERN_ERR "SELinux: conditional expressions uses unknown operator.\n");
380 if (expr->bool > p->p_bools.nprim) {
381 printk(KERN_ERR "SELinux: conditional expressions uses unknown bool.\n");
387 static int cond_read_node(struct policydb *p, struct cond_node *node, void *fp)
392 struct cond_expr *expr = NULL, *last = NULL;
394 rc = next_entry(buf, fp, sizeof(u32));
398 node->cur_state = le32_to_cpu(buf[0]);
401 rc = next_entry(buf, fp, sizeof(u32));
406 len = le32_to_cpu(buf[0]);
408 for (i = 0; i < len; i++) {
409 rc = next_entry(buf, fp, sizeof(u32) * 2);
414 expr = kzalloc(sizeof(struct cond_expr), GFP_KERNEL);
418 expr->expr_type = le32_to_cpu(buf[0]);
419 expr->bool = le32_to_cpu(buf[1]);
421 if (!expr_isvalid(p, expr)) {
434 rc = cond_read_av_list(p, fp, &node->true_list, NULL);
437 rc = cond_read_av_list(p, fp, &node->false_list, node->true_list);
442 cond_node_destroy(node);
446 int cond_read_list(struct policydb *p, void *fp)
448 struct cond_node *node, *last = NULL;
453 rc = next_entry(buf, fp, sizeof buf);
457 len = le32_to_cpu(buf[0]);
459 rc = avtab_alloc(&(p->te_cond_avtab), p->te_avtab.nel);
463 for (i = 0; i < len; i++) {
465 node = kzalloc(sizeof(struct cond_node), GFP_KERNEL);
469 rc = cond_read_node(p, node, fp);
481 cond_list_destroy(p->cond_list);
486 /* Determine whether additional permissions are granted by the conditional
487 * av table, and if so, add them to the result
489 void cond_compute_av(struct avtab *ctab, struct avtab_key *key, struct av_decision *avd)
491 struct avtab_node *node;
493 if (!ctab || !key || !avd)
496 for (node = avtab_search_node(ctab, key); node;
497 node = avtab_search_node_next(node, key->specified)) {
498 if ((u16)(AVTAB_ALLOWED|AVTAB_ENABLED) ==
499 (node->key.specified & (AVTAB_ALLOWED|AVTAB_ENABLED)))
500 avd->allowed |= node->datum.data;
501 if ((u16)(AVTAB_AUDITDENY|AVTAB_ENABLED) ==
502 (node->key.specified & (AVTAB_AUDITDENY|AVTAB_ENABLED)))
503 /* Since a '0' in an auditdeny mask represents a
504 * permission we do NOT want to audit (dontaudit), we use
505 * the '&' operand to ensure that all '0's in the mask
506 * are retained (much unlike the allow and auditallow cases).
508 avd->auditdeny &= node->datum.data;
509 if ((u16)(AVTAB_AUDITALLOW|AVTAB_ENABLED) ==
510 (node->key.specified & (AVTAB_AUDITALLOW|AVTAB_ENABLED)))
511 avd->auditallow |= node->datum.data;