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)
122 p->bool_val_to_struct = NULL;
125 rc = avtab_init(&p->te_cond_avtab);
132 static void cond_av_list_destroy(struct cond_av_list *list)
134 struct cond_av_list *cur, *next;
135 for (cur = list; cur; cur = next) {
137 /* the avtab_ptr_t node is destroy by the avtab */
142 static void cond_node_destroy(struct cond_node *node)
144 struct cond_expr *cur_expr, *next_expr;
146 for (cur_expr = node->expr; cur_expr; cur_expr = next_expr) {
147 next_expr = cur_expr->next;
150 cond_av_list_destroy(node->true_list);
151 cond_av_list_destroy(node->false_list);
155 static void cond_list_destroy(struct cond_node *list)
157 struct cond_node *next, *cur;
162 for (cur = list; cur; cur = next) {
164 cond_node_destroy(cur);
168 void cond_policydb_destroy(struct policydb *p)
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 kfree(p->bool_val_to_struct);
178 p->bool_val_to_struct = (struct cond_bool_datum **)
179 kmalloc(p->p_bools.nprim * sizeof(struct cond_bool_datum *), GFP_KERNEL);
180 if (!p->bool_val_to_struct)
185 int cond_destroy_bool(void *key, void *datum, void *p)
192 int cond_index_bool(void *key, void *datum, void *datap)
195 struct cond_bool_datum *booldatum;
200 if (!booldatum->value || booldatum->value > p->p_bools.nprim)
203 p->p_bool_val_to_name[booldatum->value - 1] = key;
204 p->bool_val_to_struct[booldatum->value - 1] = booldatum;
209 static int bool_isvalid(struct cond_bool_datum *b)
211 if (!(b->state == 0 || b->state == 1))
216 int cond_read_bool(struct policydb *p, struct hashtab *h, void *fp)
219 struct cond_bool_datum *booldatum;
224 booldatum = kzalloc(sizeof(struct cond_bool_datum), GFP_KERNEL);
228 rc = next_entry(buf, fp, sizeof buf);
232 booldatum->value = le32_to_cpu(buf[0]);
233 booldatum->state = le32_to_cpu(buf[1]);
235 if (!bool_isvalid(booldatum))
238 len = le32_to_cpu(buf[2]);
240 key = kmalloc(len + 1, GFP_KERNEL);
243 rc = next_entry(key, fp, len);
247 if (hashtab_insert(h, key, booldatum))
252 cond_destroy_bool(key, booldatum, NULL);
256 struct cond_insertf_data {
258 struct cond_av_list *other;
259 struct cond_av_list *head;
260 struct cond_av_list *tail;
263 static int cond_insertf(struct avtab *a, struct avtab_key *k, struct avtab_datum *d, void *ptr)
265 struct cond_insertf_data *data = ptr;
266 struct policydb *p = data->p;
267 struct cond_av_list *other = data->other, *list, *cur;
268 struct avtab_node *node_ptr;
273 * For type rules we have to make certain there aren't any
274 * conflicting rules by searching the te_avtab and the
277 if (k->specified & AVTAB_TYPE) {
278 if (avtab_search(&p->te_avtab, k)) {
279 printk(KERN_ERR "SELinux: type rule already exists outside of a conditional.\n");
283 * If we are reading the false list other will be a pointer to
284 * the true list. We can have duplicate entries if there is only
285 * 1 other entry and it is in our true list.
287 * If we are reading the true list (other == NULL) there shouldn't
288 * be any other entries.
291 node_ptr = avtab_search_node(&p->te_cond_avtab, k);
293 if (avtab_search_node_next(node_ptr, k->specified)) {
294 printk(KERN_ERR "SELinux: too many conflicting type rules.\n");
298 for (cur = other; cur; cur = cur->next) {
299 if (cur->node == node_ptr) {
305 printk(KERN_ERR "SELinux: conflicting type rules.\n");
310 if (avtab_search(&p->te_cond_avtab, k)) {
311 printk(KERN_ERR "SELinux: conflicting type rules when adding type rule for true.\n");
317 node_ptr = avtab_insert_nonunique(&p->te_cond_avtab, k, d);
319 printk(KERN_ERR "SELinux: could not insert rule.\n");
324 list = kzalloc(sizeof(struct cond_av_list), GFP_KERNEL);
330 list->node = node_ptr;
334 data->tail->next = list;
339 cond_av_list_destroy(data->head);
344 static int cond_read_av_list(struct policydb *p, void *fp, struct cond_av_list **ret_list, struct cond_av_list *other)
349 struct cond_insertf_data data;
354 rc = next_entry(buf, fp, sizeof(u32));
358 len = le32_to_cpu(buf[0]);
366 for (i = 0; i < len; i++) {
367 rc = avtab_read_item(&p->te_cond_avtab, fp, p, cond_insertf,
373 *ret_list = data.head;
377 static int expr_isvalid(struct policydb *p, struct cond_expr *expr)
379 if (expr->expr_type <= 0 || expr->expr_type > COND_LAST) {
380 printk(KERN_ERR "SELinux: conditional expressions uses unknown operator.\n");
384 if (expr->bool > p->p_bools.nprim) {
385 printk(KERN_ERR "SELinux: conditional expressions uses unknown bool.\n");
391 static int cond_read_node(struct policydb *p, struct cond_node *node, void *fp)
396 struct cond_expr *expr = NULL, *last = NULL;
398 rc = next_entry(buf, fp, sizeof(u32));
402 node->cur_state = le32_to_cpu(buf[0]);
405 rc = next_entry(buf, fp, sizeof(u32));
410 len = le32_to_cpu(buf[0]);
412 for (i = 0; i < len; i++) {
413 rc = next_entry(buf, fp, sizeof(u32) * 2);
418 expr = kzalloc(sizeof(struct cond_expr), GFP_KERNEL);
422 expr->expr_type = le32_to_cpu(buf[0]);
423 expr->bool = le32_to_cpu(buf[1]);
425 if (!expr_isvalid(p, expr)) {
438 rc = cond_read_av_list(p, fp, &node->true_list, NULL);
441 rc = cond_read_av_list(p, fp, &node->false_list, node->true_list);
446 cond_node_destroy(node);
450 int cond_read_list(struct policydb *p, void *fp)
452 struct cond_node *node, *last = NULL;
457 rc = next_entry(buf, fp, sizeof buf);
461 len = le32_to_cpu(buf[0]);
463 rc = avtab_alloc(&(p->te_cond_avtab), p->te_avtab.nel);
467 for (i = 0; i < len; i++) {
469 node = kzalloc(sizeof(struct cond_node), GFP_KERNEL);
473 rc = cond_read_node(p, node, fp);
485 cond_list_destroy(p->cond_list);
490 /* Determine whether additional permissions are granted by the conditional
491 * av table, and if so, add them to the result
493 void cond_compute_av(struct avtab *ctab, struct avtab_key *key, struct av_decision *avd)
495 struct avtab_node *node;
497 if (!ctab || !key || !avd)
500 for (node = avtab_search_node(ctab, key); node;
501 node = avtab_search_node_next(node, key->specified)) {
502 if ((u16)(AVTAB_ALLOWED|AVTAB_ENABLED) ==
503 (node->key.specified & (AVTAB_ALLOWED|AVTAB_ENABLED)))
504 avd->allowed |= node->datum.data;
505 if ((u16)(AVTAB_AUDITDENY|AVTAB_ENABLED) ==
506 (node->key.specified & (AVTAB_AUDITDENY|AVTAB_ENABLED)))
507 /* Since a '0' in an auditdeny mask represents a
508 * permission we do NOT want to audit (dontaudit), we use
509 * the '&' operand to ensure that all '0's in the mask
510 * are retained (much unlike the allow and auditallow cases).
512 avd->auditdeny &= node->datum.data;
513 if ((u16)(AVTAB_AUDITALLOW|AVTAB_ENABLED) ==
514 (node->key.specified & (AVTAB_AUDITALLOW|AVTAB_ENABLED)))
515 avd->auditallow |= node->datum.data;