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 00000000000..b53441184ac
--- /dev/null
+++ b/security/selinux/ss/conditional.c
@@ -0,0 +1,489 @@
+/* Authors: Karl MacMillan <kmacmillan@tresys.com>
+ *          Frank Mayer <mayerf@tresys.com>
+ *
+ * Copyright (C) 2003 - 2004 Tresys Technology, LLC
+ *	This program is free software; you can redistribute it and/or modify
+ *  	it under the terms of the GNU General Public License as published by
+ *	the Free Software Foundation, version 2.
+ */
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/spinlock.h>
+#include <asm/semaphore.h>
+#include <linux/slab.h>
+
+#include "security.h"
+#include "conditional.h"
+
+/*
+ * cond_evaluate_expr evaluates a conditional expr
+ * in reverse polish notation. It returns true (1), false (0),
+ * or undefined (-1). Undefined occurs when the expression
+ * exceeds the stack depth of COND_EXPR_MAXDEPTH.
+ */
+static int cond_evaluate_expr(struct policydb *p, struct cond_expr *expr)
+{
+
+	struct cond_expr *cur;
+	int s[COND_EXPR_MAXDEPTH];
+	int sp = -1;
+
+	for (cur = expr; cur != NULL; cur = cur->next) {
+		switch (cur->expr_type) {
+		case COND_BOOL:
+			if (sp == (COND_EXPR_MAXDEPTH - 1))
+				return -1;
+			sp++;
+			s[sp] = p->bool_val_to_struct[cur->bool - 1]->state;
+			break;
+		case COND_NOT:
+			if (sp < 0)
+				return -1;
+			s[sp] = !s[sp];
+			break;
+		case COND_OR:
+			if (sp < 1)
+				return -1;
+			sp--;
+			s[sp] |= s[sp + 1];
+			break;
+		case COND_AND:
+			if (sp < 1)
+				return -1;
+			sp--;
+			s[sp] &= s[sp + 1];
+			break;
+		case COND_XOR:
+			if (sp < 1)
+				return -1;
+			sp--;
+			s[sp] ^= s[sp + 1];
+			break;
+		case COND_EQ:
+			if (sp < 1)
+				return -1;
+			sp--;
+			s[sp] = (s[sp] == s[sp + 1]);
+			break;
+		case COND_NEQ:
+			if (sp < 1)
+				return -1;
+			sp--;
+			s[sp] = (s[sp] != s[sp + 1]);
+			break;
+		default:
+			return -1;
+		}
+	}
+	return s[0];
+}
+
+/*
+ * evaluate_cond_node evaluates the conditional stored in
+ * a struct cond_node and if the result is different than the
+ * current state of the node it sets the rules in the true/false
+ * list appropriately. If the result of the expression is undefined
+ * all of the rules are disabled for safety.
+ */
+int evaluate_cond_node(struct policydb *p, struct cond_node *node)
+{
+	int new_state;
+	struct cond_av_list* cur;
+
+	new_state = cond_evaluate_expr(p, node->expr);
+	if (new_state != node->cur_state) {
+		node->cur_state = new_state;
+		if (new_state == -1)
+			printk(KERN_ERR "security: expression result was undefined - disabling all rules.\n");
+		/* turn the rules on or off */
+		for (cur = node->true_list; cur != NULL; cur = cur->next) {
+			if (new_state <= 0) {
+				cur->node->datum.specified &= ~AVTAB_ENABLED;
+			} else {
+				cur->node->datum.specified |= AVTAB_ENABLED;
+			}
+		}
+
+		for (cur = node->false_list; cur != NULL; cur = cur->next) {
+			/* -1 or 1 */
+			if (new_state) {
+				cur->node->datum.specified &= ~AVTAB_ENABLED;
+			} else {
+				cur->node->datum.specified |= AVTAB_ENABLED;
+			}
+		}
+	}
+	return 0;
+}
+
+int cond_policydb_init(struct policydb *p)
+{
+	p->bool_val_to_struct = NULL;
+	p->cond_list = NULL;
+	if (avtab_init(&p->te_cond_avtab))
+		return -1;
+
+	return 0;
+}
+
+static void cond_av_list_destroy(struct cond_av_list *list)
+{
+	struct cond_av_list *cur, *next;
+	for (cur = list; cur != NULL; cur = next) {
+		next = cur->next;
+		/* the avtab_ptr_t node is destroy by the avtab */
+		kfree(cur);
+	}
+}
+
+static void cond_node_destroy(struct cond_node *node)
+{
+	struct cond_expr *cur_expr, *next_expr;
+
+	for (cur_expr = node->expr; cur_expr != NULL; cur_expr = next_expr) {
+		next_expr = cur_expr->next;
+		kfree(cur_expr);
+	}
+	cond_av_list_destroy(node->true_list);
+	cond_av_list_destroy(node->false_list);
+	kfree(node);
+}
+
+static void cond_list_destroy(struct cond_node *list)
+{
+	struct cond_node *next, *cur;
+
+	if (list == NULL)
+		return;
+
+	for (cur = list; cur != NULL; cur = next) {
+		next = cur->next;
+		cond_node_destroy(cur);
+	}
+}
+
+void cond_policydb_destroy(struct policydb *p)
+{
+	if (p->bool_val_to_struct != NULL)
+		kfree(p->bool_val_to_struct);
+	avtab_destroy(&p->te_cond_avtab);
+	cond_list_destroy(p->cond_list);
+}
+
+int cond_init_bool_indexes(struct policydb *p)
+{
+	if (p->bool_val_to_struct)
+		kfree(p->bool_val_to_struct);
+	p->bool_val_to_struct = (struct cond_bool_datum**)
+		kmalloc(p->p_bools.nprim * sizeof(struct cond_bool_datum*), GFP_KERNEL);
+	if (!p->bool_val_to_struct)
+		return -1;
+	return 0;
+}
+
+int cond_destroy_bool(void *key, void *datum, void *p)
+{
+	if (key)
+		kfree(key);
+	kfree(datum);
+	return 0;
+}
+
+int cond_index_bool(void *key, void *datum, void *datap)
+{
+	struct policydb *p;
+	struct cond_bool_datum *booldatum;
+
+	booldatum = datum;
+	p = datap;
+
+	if (!booldatum->value || booldatum->value > p->p_bools.nprim)
+		return -EINVAL;
+
+	p->p_bool_val_to_name[booldatum->value - 1] = key;
+	p->bool_val_to_struct[booldatum->value -1] = booldatum;
+
+	return 0;
+}
+
+static int bool_isvalid(struct cond_bool_datum *b)
+{
+	if (!(b->state == 0 || b->state == 1))
+		return 0;
+	return 1;
+}
+
+int cond_read_bool(struct policydb *p, struct hashtab *h, void *fp)
+{
+	char *key = NULL;
+	struct cond_bool_datum *booldatum;
+	u32 buf[3], len;
+	int rc;
+
+	booldatum = kmalloc(sizeof(struct cond_bool_datum), GFP_KERNEL);
+	if (!booldatum)
+		return -1;
+	memset(booldatum, 0, sizeof(struct cond_bool_datum));
+
+	rc = next_entry(buf, fp, sizeof buf);
+	if (rc < 0)
+		goto err;
+
+	booldatum->value = le32_to_cpu(buf[0]);
+	booldatum->state = le32_to_cpu(buf[1]);
+
+	if (!bool_isvalid(booldatum))
+		goto err;
+
+	len = le32_to_cpu(buf[2]);
+
+	key = kmalloc(len + 1, GFP_KERNEL);
+	if (!key)
+		goto err;
+	rc = next_entry(key, fp, len);
+	if (rc < 0)
+		goto err;
+	key[len] = 0;
+	if (hashtab_insert(h, key, booldatum))
+		goto err;
+
+	return 0;
+err:
+	cond_destroy_bool(key, booldatum, NULL);
+	return -1;
+}
+
+static int cond_read_av_list(struct policydb *p, void *fp, struct cond_av_list **ret_list,
+			     struct cond_av_list *other)
+{
+	struct cond_av_list *list, *last = NULL, *cur;
+	struct avtab_key key;
+	struct avtab_datum datum;
+	struct avtab_node *node_ptr;
+	int rc;
+	u32 buf[1], i, len;
+	u8 found;
+
+	*ret_list = NULL;
+
+	len = 0;
+	rc = next_entry(buf, fp, sizeof buf);
+	if (rc < 0)
+		return -1;
+
+	len = le32_to_cpu(buf[0]);
+	if (len == 0) {
+		return 0;
+	}
+
+	for (i = 0; i < len; i++) {
+		if (avtab_read_item(fp, &datum, &key))
+			goto err;
+
+		/*
+		 * For type rules we have to make certain there aren't any
+		 * conflicting rules by searching the te_avtab and the
+		 * cond_te_avtab.
+		 */
+		if (datum.specified & AVTAB_TYPE) {
+			if (avtab_search(&p->te_avtab, &key, AVTAB_TYPE)) {
+				printk("security: type rule already exists outside of a conditional.");
+				goto err;
+			}
+			/*
+			 * If we are reading the false list other will be a pointer to
+			 * the true list. We can have duplicate entries if there is only
+			 * 1 other entry and it is in our true list.
+			 *
+			 * If we are reading the true list (other == NULL) there shouldn't
+			 * be any other entries.
+			 */
+			if (other) {
+				node_ptr = avtab_search_node(&p->te_cond_avtab, &key, AVTAB_TYPE);
+				if (node_ptr) {
+					if (avtab_search_node_next(node_ptr, AVTAB_TYPE)) {
+						printk("security: too many conflicting type rules.");
+						goto err;
+					}
+					found = 0;
+					for (cur = other; cur != NULL; cur = cur->next) {
+						if (cur->node == node_ptr) {
+							found = 1;
+							break;
+						}
+					}
+					if (!found) {
+						printk("security: conflicting type rules.");
+						goto err;
+					}
+				}
+			} else {
+				if (avtab_search(&p->te_cond_avtab, &key, AVTAB_TYPE)) {
+					printk("security: conflicting type rules when adding type rule for true.");
+					goto err;
+				}
+			}
+		}
+		node_ptr = avtab_insert_nonunique(&p->te_cond_avtab, &key, &datum);
+		if (!node_ptr) {
+			printk("security: could not insert rule.");
+			goto err;
+		}
+
+		list = kmalloc(sizeof(struct cond_av_list), GFP_KERNEL);
+		if (!list)
+			goto err;
+		memset(list, 0, sizeof(struct cond_av_list));
+
+		list->node = node_ptr;
+		if (i == 0)
+			*ret_list = list;
+		else
+			last->next = list;
+		last = list;
+
+	}
+
+	return 0;
+err:
+	cond_av_list_destroy(*ret_list);
+	*ret_list = NULL;
+	return -1;
+}
+
+static int expr_isvalid(struct policydb *p, struct cond_expr *expr)
+{
+	if (expr->expr_type <= 0 || expr->expr_type > COND_LAST) {
+		printk("security: conditional expressions uses unknown operator.\n");
+		return 0;
+	}
+
+	if (expr->bool > p->p_bools.nprim) {
+		printk("security: conditional expressions uses unknown bool.\n");
+		return 0;
+	}
+	return 1;
+}
+
+static int cond_read_node(struct policydb *p, struct cond_node *node, void *fp)
+{
+	u32 buf[2], len, i;
+	int rc;
+	struct cond_expr *expr = NULL, *last = NULL;
+
+	rc = next_entry(buf, fp, sizeof(u32));
+	if (rc < 0)
+		return -1;
+
+	node->cur_state = le32_to_cpu(buf[0]);
+
+	len = 0;
+	rc = next_entry(buf, fp, sizeof(u32));
+	if (rc < 0)
+		return -1;
+
+	/* expr */
+	len = le32_to_cpu(buf[0]);
+
+	for (i = 0; i < len; i++ ) {
+		rc = next_entry(buf, fp, sizeof(u32) * 2);
+		if (rc < 0)
+			goto err;
+
+		expr = kmalloc(sizeof(struct cond_expr), GFP_KERNEL);
+		if (!expr) {
+			goto err;
+		}
+		memset(expr, 0, sizeof(struct cond_expr));
+
+		expr->expr_type = le32_to_cpu(buf[0]);
+		expr->bool = le32_to_cpu(buf[1]);
+
+		if (!expr_isvalid(p, expr)) {
+			kfree(expr);
+			goto err;
+		}
+
+		if (i == 0) {
+			node->expr = expr;
+		} else {
+			last->next = expr;
+		}
+		last = expr;
+	}
+
+	if (cond_read_av_list(p, fp, &node->true_list, NULL) != 0)
+		goto err;
+	if (cond_read_av_list(p, fp, &node->false_list, node->true_list) != 0)
+		goto err;
+	return 0;
+err:
+	cond_node_destroy(node);
+	return -1;
+}
+
+int cond_read_list(struct policydb *p, void *fp)
+{
+	struct cond_node *node, *last = NULL;
+	u32 buf[1], i, len;
+	int rc;
+
+	rc = next_entry(buf, fp, sizeof buf);
+	if (rc < 0)
+		return -1;
+
+	len = le32_to_cpu(buf[0]);
+
+	for (i = 0; i < len; i++) {
+		node = kmalloc(sizeof(struct cond_node), GFP_KERNEL);
+		if (!node)
+			goto err;
+		memset(node, 0, sizeof(struct cond_node));
+
+		if (cond_read_node(p, node, fp) != 0)
+			goto err;
+
+		if (i == 0) {
+			p->cond_list = node;
+		} else {
+			last->next = node;
+		}
+		last = node;
+	}
+	return 0;
+err:
+	cond_list_destroy(p->cond_list);
+	return -1;
+}
+
+/* Determine whether additional permissions are granted by the conditional
+ * av table, and if so, add them to the result
+ */
+void cond_compute_av(struct avtab *ctab, struct avtab_key *key, struct av_decision *avd)
+{
+	struct avtab_node *node;
+
+	if(!ctab || !key || !avd)
+		return;
+
+	for(node = avtab_search_node(ctab, key, AVTAB_AV); node != NULL;
+				node = avtab_search_node_next(node, AVTAB_AV)) {
+		if ( (__u32) (AVTAB_ALLOWED|AVTAB_ENABLED) ==
+		     (node->datum.specified & (AVTAB_ALLOWED|AVTAB_ENABLED)))
+			avd->allowed |= avtab_allowed(&node->datum);
+		if ( (__u32) (AVTAB_AUDITDENY|AVTAB_ENABLED) ==
+		     (node->datum.specified & (AVTAB_AUDITDENY|AVTAB_ENABLED)))
+			/* Since a '0' in an auditdeny mask represents a
+			 * permission we do NOT want to audit (dontaudit), we use
+			 * the '&' operand to ensure that all '0's in the mask
+			 * are retained (much unlike the allow and auditallow cases).
+			 */
+			avd->auditdeny &= avtab_auditdeny(&node->datum);
+		if ( (__u32) (AVTAB_AUDITALLOW|AVTAB_ENABLED) ==
+		     (node->datum.specified & (AVTAB_AUDITALLOW|AVTAB_ENABLED)))
+			avd->auditallow |= avtab_auditallow(&node->datum);
+	}
+	return;
+}