1 files changed, 648 insertions, 0 deletions

diff --git a/security/selinux/ss/conditional.c b/security/selinux/ss/conditional.c
new file mode 100644
index 00000000..a5337320
--- /dev/null
+++ b/security/selinux/ss/conditional.c
@@ -0,0 +1,648 @@
+/* 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 <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; 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 "SELinux: expression result was undefined - disabling all rules.\n");
+		/* turn the rules on or off */
+		for (cur = node->true_list; cur; cur = cur->next) {
+			if (new_state <= 0)
+				cur->node->key.specified &= ~AVTAB_ENABLED;
+			else
+				cur->node->key.specified |= AVTAB_ENABLED;
+		}
+
+		for (cur = node->false_list; cur; cur = cur->next) {
+			/* -1 or 1 */
+			if (new_state)
+				cur->node->key.specified &= ~AVTAB_ENABLED;
+			else
+				cur->node->key.specified |= AVTAB_ENABLED;
+		}
+	}
+	return 0;
+}
+
+int cond_policydb_init(struct policydb *p)
+{
+	int rc;
+
+	p->bool_val_to_struct = NULL;
+	p->cond_list = NULL;
+
+	rc = avtab_init(&p->te_cond_avtab);
+	if (rc)
+		return rc;
+
+	return 0;
+}
+
+static void cond_av_list_destroy(struct cond_av_list *list)
+{
+	struct cond_av_list *cur, *next;
+	for (cur = list; cur; 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; 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; cur = next) {
+		next = cur->next;
+		cond_node_destroy(cur);
+	}
+}
+
+void cond_policydb_destroy(struct policydb *p)
+{
+	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)
+{
+	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 -ENOMEM;
+	return 0;
+}
+
+int cond_destroy_bool(void *key, void *datum, void *p)
+{
+	kfree(key);
+	kfree(datum);
+	return 0;
+}
+
+int cond_index_bool(void *key, void *datum, void *datap)
+{
+	struct policydb *p;
+	struct cond_bool_datum *booldatum;
+	struct flex_array *fa;
+
+	booldatum = datum;
+	p = datap;
+
+	if (!booldatum->value || booldatum->value > p->p_bools.nprim)
+		return -EINVAL;
+
+	fa = p->sym_val_to_name[SYM_BOOLS];
+	if (flex_array_put_ptr(fa, booldatum->value - 1, key,
+			       GFP_KERNEL | __GFP_ZERO))
+		BUG();
+	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;
+	__le32 buf[3];
+	u32 len;
+	int rc;
+
+	booldatum = kzalloc(sizeof(struct cond_bool_datum), GFP_KERNEL);
+	if (!booldatum)
+		return -ENOMEM;
+
+	rc = next_entry(buf, fp, sizeof buf);
+	if (rc)
+		goto err;
+
+	booldatum->value = le32_to_cpu(buf[0]);
+	booldatum->state = le32_to_cpu(buf[1]);
+
+	rc = -EINVAL;
+	if (!bool_isvalid(booldatum))
+		goto err;
+
+	len = le32_to_cpu(buf[2]);
+
+	rc = -ENOMEM;
+	key = kmalloc(len + 1, GFP_KERNEL);
+	if (!key)
+		goto err;
+	rc = next_entry(key, fp, len);
+	if (rc)
+		goto err;
+	key[len] = '\0';
+	rc = hashtab_insert(h, key, booldatum);
+	if (rc)
+		goto err;
+
+	return 0;
+err:
+	cond_destroy_bool(key, booldatum, NULL);
+	return rc;
+}
+
+struct cond_insertf_data {
+	struct policydb *p;
+	struct cond_av_list *other;
+	struct cond_av_list *head;
+	struct cond_av_list *tail;
+};
+
+static int cond_insertf(struct avtab *a, struct avtab_key *k, struct avtab_datum *d, void *ptr)
+{
+	struct cond_insertf_data *data = ptr;
+	struct policydb *p = data->p;
+	struct cond_av_list *other = data->other, *list, *cur;
+	struct avtab_node *node_ptr;
+	u8 found;
+	int rc = -EINVAL;
+
+	/*
+	 * 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 (k->specified & AVTAB_TYPE) {
+		if (avtab_search(&p->te_avtab, k)) {
+			printk(KERN_ERR "SELinux: type rule already exists outside of a conditional.\n");
+			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, k);
+			if (node_ptr) {
+				if (avtab_search_node_next(node_ptr, k->specified)) {
+					printk(KERN_ERR "SELinux: too many conflicting type rules.\n");
+					goto err;
+				}
+				found = 0;
+				for (cur = other; cur; cur = cur->next) {
+					if (cur->node == node_ptr) {
+						found = 1;
+						break;
+					}
+				}
+				if (!found) {
+					printk(KERN_ERR "SELinux: conflicting type rules.\n");
+					goto err;
+				}
+			}
+		} else {
+			if (avtab_search(&p->te_cond_avtab, k)) {
+				printk(KERN_ERR "SELinux: conflicting type rules when adding type rule for true.\n");
+				goto err;
+			}
+		}
+	}
+
+	node_ptr = avtab_insert_nonunique(&p->te_cond_avtab, k, d);
+	if (!node_ptr) {
+		printk(KERN_ERR "SELinux: could not insert rule.\n");
+		rc = -ENOMEM;
+		goto err;
+	}
+
+	list = kzalloc(sizeof(struct cond_av_list), GFP_KERNEL);
+	if (!list) {
+		rc = -ENOMEM;
+		goto err;
+	}
+
+	list->node = node_ptr;
+	if (!data->head)
+		data->head = list;
+	else
+		data->tail->next = list;
+	data->tail = list;
+	return 0;
+
+err:
+	cond_av_list_destroy(data->head);
+	data->head = NULL;
+	return rc;
+}
+
+static int cond_read_av_list(struct policydb *p, void *fp, struct cond_av_list **ret_list, struct cond_av_list *other)
+{
+	int i, rc;
+	__le32 buf[1];
+	u32 len;
+	struct cond_insertf_data data;
+
+	*ret_list = NULL;
+
+	len = 0;
+	rc = next_entry(buf, fp, sizeof(u32));
+	if (rc)
+		return rc;
+
+	len = le32_to_cpu(buf[0]);
+	if (len == 0)
+		return 0;
+
+	data.p = p;
+	data.other = other;
+	data.head = NULL;
+	data.tail = NULL;
+	for (i = 0; i < len; i++) {
+		rc = avtab_read_item(&p->te_cond_avtab, fp, p, cond_insertf,
+				     &data);
+		if (rc)
+			return rc;
+	}
+
+	*ret_list = data.head;
+	return 0;
+}
+
+static int expr_isvalid(struct policydb *p, struct cond_expr *expr)
+{
+	if (expr->expr_type <= 0 || expr->expr_type > COND_LAST) {
+		printk(KERN_ERR "SELinux: conditional expressions uses unknown operator.\n");
+		return 0;
+	}
+
+	if (expr->bool > p->p_bools.nprim) {
+		printk(KERN_ERR "SELinux: conditional expressions uses unknown bool.\n");
+		return 0;
+	}
+	return 1;
+}
+
+static int cond_read_node(struct policydb *p, struct cond_node *node, void *fp)
+{
+	__le32 buf[2];
+	u32 len, i;
+	int rc;
+	struct cond_expr *expr = NULL, *last = NULL;
+
+	rc = next_entry(buf, fp, sizeof(u32));
+	if (rc)
+		return rc;
+
+	node->cur_state = le32_to_cpu(buf[0]);
+
+	len = 0;
+	rc = next_entry(buf, fp, sizeof(u32));
+	if (rc)
+		return rc;
+
+	/* expr */
+	len = le32_to_cpu(buf[0]);
+
+	for (i = 0; i < len; i++) {
+		rc = next_entry(buf, fp, sizeof(u32) * 2);
+		if (rc)
+			goto err;
+
+		rc = -ENOMEM;
+		expr = kzalloc(sizeof(struct cond_expr), GFP_KERNEL);
+		if (!expr)
+			goto err;
+
+		expr->expr_type = le32_to_cpu(buf[0]);
+		expr->bool = le32_to_cpu(buf[1]);
+
+		if (!expr_isvalid(p, expr)) {
+			rc = -EINVAL;
+			kfree(expr);
+			goto err;
+		}
+
+		if (i == 0)
+			node->expr = expr;
+		else
+			last->next = expr;
+		last = expr;
+	}
+
+	rc = cond_read_av_list(p, fp, &node->true_list, NULL);
+	if (rc)
+		goto err;
+	rc = cond_read_av_list(p, fp, &node->false_list, node->true_list);
+	if (rc)
+		goto err;
+	return 0;
+err:
+	cond_node_destroy(node);
+	return rc;
+}
+
+int cond_read_list(struct policydb *p, void *fp)
+{
+	struct cond_node *node, *last = NULL;
+	__le32 buf[1];
+	u32 i, len;
+	int rc;
+
+	rc = next_entry(buf, fp, sizeof buf);
+	if (rc)
+		return rc;
+
+	len = le32_to_cpu(buf[0]);
+
+	rc = avtab_alloc(&(p->te_cond_avtab), p->te_avtab.nel);
+	if (rc)
+		goto err;
+
+	for (i = 0; i < len; i++) {
+		rc = -ENOMEM;
+		node = kzalloc(sizeof(struct cond_node), GFP_KERNEL);
+		if (!node)
+			goto err;
+
+		rc = cond_read_node(p, node, fp);
+		if (rc)
+			goto err;
+
+		if (i == 0)
+			p->cond_list = node;
+		else
+			last->next = node;
+		last = node;
+	}
+	return 0;
+err:
+	cond_list_destroy(p->cond_list);
+	p->cond_list = NULL;
+	return rc;
+}
+
+int cond_write_bool(void *vkey, void *datum, void *ptr)
+{
+	char *key = vkey;
+	struct cond_bool_datum *booldatum = datum;
+	struct policy_data *pd = ptr;
+	void *fp = pd->fp;
+	__le32 buf[3];
+	u32 len;
+	int rc;
+
+	len = strlen(key);
+	buf[0] = cpu_to_le32(booldatum->value);
+	buf[1] = cpu_to_le32(booldatum->state);
+	buf[2] = cpu_to_le32(len);
+	rc = put_entry(buf, sizeof(u32), 3, fp);
+	if (rc)
+		return rc;
+	rc = put_entry(key, 1, len, fp);
+	if (rc)
+		return rc;
+	return 0;
+}
+
+/*
+ * cond_write_cond_av_list doesn't write out the av_list nodes.
+ * Instead it writes out the key/value pairs from the avtab. This
+ * is necessary because there is no way to uniquely identifying rules
+ * in the avtab so it is not possible to associate individual rules
+ * in the avtab with a conditional without saving them as part of
+ * the conditional. This means that the avtab with the conditional
+ * rules will not be saved but will be rebuilt on policy load.
+ */
+static int cond_write_av_list(struct policydb *p,
+			      struct cond_av_list *list, struct policy_file *fp)
+{
+	__le32 buf[1];
+	struct cond_av_list *cur_list;
+	u32 len;
+	int rc;
+
+	len = 0;
+	for (cur_list = list; cur_list != NULL; cur_list = cur_list->next)
+		len++;
+
+	buf[0] = cpu_to_le32(len);
+	rc = put_entry(buf, sizeof(u32), 1, fp);
+	if (rc)
+		return rc;
+
+	if (len == 0)
+		return 0;
+
+	for (cur_list = list; cur_list != NULL; cur_list = cur_list->next) {
+		rc = avtab_write_item(p, cur_list->node, fp);
+		if (rc)
+			return rc;
+	}
+
+	return 0;
+}
+
+int cond_write_node(struct policydb *p, struct cond_node *node,
+		    struct policy_file *fp)
+{
+	struct cond_expr *cur_expr;
+	__le32 buf[2];
+	int rc;
+	u32 len = 0;
+
+	buf[0] = cpu_to_le32(node->cur_state);
+	rc = put_entry(buf, sizeof(u32), 1, fp);
+	if (rc)
+		return rc;
+
+	for (cur_expr = node->expr; cur_expr != NULL; cur_expr = cur_expr->next)
+		len++;
+
+	buf[0] = cpu_to_le32(len);
+	rc = put_entry(buf, sizeof(u32), 1, fp);
+	if (rc)
+		return rc;
+
+	for (cur_expr = node->expr; cur_expr != NULL; cur_expr = cur_expr->next) {
+		buf[0] = cpu_to_le32(cur_expr->expr_type);
+		buf[1] = cpu_to_le32(cur_expr->bool);
+		rc = put_entry(buf, sizeof(u32), 2, fp);
+		if (rc)
+			return rc;
+	}
+
+	rc = cond_write_av_list(p, node->true_list, fp);
+	if (rc)
+		return rc;
+	rc = cond_write_av_list(p, node->false_list, fp);
+	if (rc)
+		return rc;
+
+	return 0;
+}
+
+int cond_write_list(struct policydb *p, struct cond_node *list, void *fp)
+{
+	struct cond_node *cur;
+	u32 len;
+	__le32 buf[1];
+	int rc;
+
+	len = 0;
+	for (cur = list; cur != NULL; cur = cur->next)
+		len++;
+	buf[0] = cpu_to_le32(len);
+	rc = put_entry(buf, sizeof(u32), 1, fp);
+	if (rc)
+		return rc;
+
+	for (cur = list; cur != NULL; cur = cur->next) {
+		rc = cond_write_node(p, cur, fp);
+		if (rc)
+			return rc;
+	}
+
+	return 0;
+}
+/* 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); node;
+				node = avtab_search_node_next(node, key->specified)) {
+		if ((u16)(AVTAB_ALLOWED|AVTAB_ENABLED) ==
+		    (node->key.specified & (AVTAB_ALLOWED|AVTAB_ENABLED)))
+			avd->allowed |= node->datum.data;
+		if ((u16)(AVTAB_AUDITDENY|AVTAB_ENABLED) ==
+		    (node->key.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 &= node->datum.data;
+		if ((u16)(AVTAB_AUDITALLOW|AVTAB_ENABLED) ==
+		    (node->key.specified & (AVTAB_AUDITALLOW|AVTAB_ENABLED)))
+			avd->auditallow |= node->datum.data;
+	}
+	return;
+}