1 files changed, 758 insertions, 0 deletions

diff --git a/security/selinux/ss/conditional.c b/security/selinux/ss/conditional.c
new file mode 100644
index 000000000..81ff676f2
--- /dev/null
+++ b/security/selinux/ss/conditional.c
@@ -0,0 +1,758 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Authors: Karl MacMillan <kmacmillan@tresys.com>
+ *	    Frank Mayer <mayerf@tresys.com>
+ *
+ * Copyright (C) 2003 - 2004 Tresys Technology, LLC
+ */
+
+#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"
+#include "services.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)
+{
+	u32 i;
+	int s[COND_EXPR_MAXDEPTH];
+	int sp = -1;
+
+	if (expr->len == 0)
+		return -1;
+
+	for (i = 0; i < expr->len; i++) {
+		struct cond_expr_node *node = &expr->nodes[i];
+
+		switch (node->expr_type) {
+		case COND_BOOL:
+			if (sp == (COND_EXPR_MAXDEPTH - 1))
+				return -1;
+			sp++;
+			s[sp] = p->bool_val_to_struct[node->boolean - 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.
+ */
+static void evaluate_cond_node(struct policydb *p, struct cond_node *node)
+{
+	struct avtab_node *avnode;
+	int new_state;
+	u32 i;
+
+	new_state = cond_evaluate_expr(p, &node->expr);
+	if (new_state != node->cur_state) {
+		node->cur_state = new_state;
+		if (new_state == -1)
+			pr_err("SELinux: expression result was undefined - disabling all rules.\n");
+		/* turn the rules on or off */
+		for (i = 0; i < node->true_list.len; i++) {
+			avnode = node->true_list.nodes[i];
+			if (new_state <= 0)
+				avnode->key.specified &= ~AVTAB_ENABLED;
+			else
+				avnode->key.specified |= AVTAB_ENABLED;
+		}
+
+		for (i = 0; i < node->false_list.len; i++) {
+			avnode = node->false_list.nodes[i];
+			/* -1 or 1 */
+			if (new_state)
+				avnode->key.specified &= ~AVTAB_ENABLED;
+			else
+				avnode->key.specified |= AVTAB_ENABLED;
+		}
+	}
+}
+
+void evaluate_cond_nodes(struct policydb *p)
+{
+	u32 i;
+
+	for (i = 0; i < p->cond_list_len; i++)
+		evaluate_cond_node(p, &p->cond_list[i]);
+}
+
+void cond_policydb_init(struct policydb *p)
+{
+	p->bool_val_to_struct = NULL;
+	p->cond_list = NULL;
+	p->cond_list_len = 0;
+
+	avtab_init(&p->te_cond_avtab);
+}
+
+static void cond_node_destroy(struct cond_node *node)
+{
+	kfree(node->expr.nodes);
+	/* the avtab_ptr_t nodes are destroyed by the avtab */
+	kfree(node->true_list.nodes);
+	kfree(node->false_list.nodes);
+}
+
+static void cond_list_destroy(struct policydb *p)
+{
+	u32 i;
+
+	for (i = 0; i < p->cond_list_len; i++)
+		cond_node_destroy(&p->cond_list[i]);
+	kfree(p->cond_list);
+	p->cond_list = NULL;
+	p->cond_list_len = 0;
+}
+
+void cond_policydb_destroy(struct policydb *p)
+{
+	kfree(p->bool_val_to_struct);
+	avtab_destroy(&p->te_cond_avtab);
+	cond_list_destroy(p);
+}
+
+int cond_init_bool_indexes(struct policydb *p)
+{
+	kfree(p->bool_val_to_struct);
+	p->bool_val_to_struct = kmalloc_array(p->p_bools.nprim,
+					      sizeof(*p->bool_val_to_struct),
+					      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;
+
+	booldatum = datum;
+	p = datap;
+
+	if (!booldatum->value || booldatum->value > p->p_bools.nprim)
+		return -EINVAL;
+
+	p->sym_val_to_name[SYM_BOOLS][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 symtab *s, void *fp)
+{
+	char *key = NULL;
+	struct cond_bool_datum *booldatum;
+	__le32 buf[3];
+	u32 len;
+	int rc;
+
+	booldatum = kzalloc(sizeof(*booldatum), 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]);
+	if (((len == 0) || (len == (u32)-1)))
+		goto err;
+
+	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 = symtab_insert(s, 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 avtab_node **dst;
+	struct cond_av_list *other;
+};
+
+static int cond_insertf(struct avtab *a, const struct avtab_key *k,
+			const struct avtab_datum *d, void *ptr)
+{
+	struct cond_insertf_data *data = ptr;
+	struct policydb *p = data->p;
+	struct cond_av_list *other = data->other;
+	struct avtab_node *node_ptr;
+	u32 i;
+	bool found;
+
+	/*
+	 * 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_node(&p->te_avtab, k)) {
+			pr_err("SELinux: type rule already exists outside of a conditional.\n");
+			return -EINVAL;
+		}
+		/*
+		 * 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)) {
+					pr_err("SELinux: too many conflicting type rules.\n");
+					return -EINVAL;
+				}
+				found = false;
+				for (i = 0; i < other->len; i++) {
+					if (other->nodes[i] == node_ptr) {
+						found = true;
+						break;
+					}
+				}
+				if (!found) {
+					pr_err("SELinux: conflicting type rules.\n");
+					return -EINVAL;
+				}
+			}
+		} else {
+			if (avtab_search_node(&p->te_cond_avtab, k)) {
+				pr_err("SELinux: conflicting type rules when adding type rule for true.\n");
+				return -EINVAL;
+			}
+		}
+	}
+
+	node_ptr = avtab_insert_nonunique(&p->te_cond_avtab, k, d);
+	if (!node_ptr) {
+		pr_err("SELinux: could not insert rule.\n");
+		return -ENOMEM;
+	}
+
+	*data->dst = node_ptr;
+	return 0;
+}
+
+static int cond_read_av_list(struct policydb *p, void *fp,
+			     struct cond_av_list *list,
+			     struct cond_av_list *other)
+{
+	int rc;
+	__le32 buf[1];
+	u32 i, len;
+	struct cond_insertf_data data;
+
+	rc = next_entry(buf, fp, sizeof(u32));
+	if (rc)
+		return rc;
+
+	len = le32_to_cpu(buf[0]);
+	if (len == 0)
+		return 0;
+
+	list->nodes = kcalloc(len, sizeof(*list->nodes), GFP_KERNEL);
+	if (!list->nodes)
+		return -ENOMEM;
+
+	data.p = p;
+	data.other = other;
+	for (i = 0; i < len; i++) {
+		data.dst = &list->nodes[i];
+		rc = avtab_read_item(&p->te_cond_avtab, fp, p, cond_insertf,
+				     &data);
+		if (rc) {
+			kfree(list->nodes);
+			list->nodes = NULL;
+			return rc;
+		}
+	}
+
+	list->len = len;
+	return 0;
+}
+
+static int expr_node_isvalid(struct policydb *p, struct cond_expr_node *expr)
+{
+	if (expr->expr_type <= 0 || expr->expr_type > COND_LAST) {
+		pr_err("SELinux: conditional expressions uses unknown operator.\n");
+		return 0;
+	}
+
+	if (expr->boolean > p->p_bools.nprim) {
+		pr_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 i, len;
+	int rc;
+
+	rc = next_entry(buf, fp, sizeof(u32) * 2);
+	if (rc)
+		return rc;
+
+	node->cur_state = le32_to_cpu(buf[0]);
+
+	/* expr */
+	len = le32_to_cpu(buf[1]);
+	node->expr.nodes = kcalloc(len, sizeof(*node->expr.nodes), GFP_KERNEL);
+	if (!node->expr.nodes)
+		return -ENOMEM;
+
+	node->expr.len = len;
+
+	for (i = 0; i < len; i++) {
+		struct cond_expr_node *expr = &node->expr.nodes[i];
+
+		rc = next_entry(buf, fp, sizeof(u32) * 2);
+		if (rc)
+			return rc;
+
+		expr->expr_type = le32_to_cpu(buf[0]);
+		expr->boolean = le32_to_cpu(buf[1]);
+
+		if (!expr_node_isvalid(p, expr))
+			return -EINVAL;
+	}
+
+	rc = cond_read_av_list(p, fp, &node->true_list, NULL);
+	if (rc)
+		return rc;
+	return cond_read_av_list(p, fp, &node->false_list, &node->true_list);
+}
+
+int cond_read_list(struct policydb *p, void *fp)
+{
+	__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]);
+
+	p->cond_list = kcalloc(len, sizeof(*p->cond_list), GFP_KERNEL);
+	if (!p->cond_list)
+		return -ENOMEM;
+
+	rc = avtab_alloc(&(p->te_cond_avtab), p->te_avtab.nel);
+	if (rc)
+		goto err;
+
+	p->cond_list_len = len;
+
+	for (i = 0; i < len; i++) {
+		rc = cond_read_node(p, &p->cond_list[i], fp);
+		if (rc)
+			goto err;
+	}
+	return 0;
+err:
+	cond_list_destroy(p);
+	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];
+	u32 i;
+	int rc;
+
+	buf[0] = cpu_to_le32(list->len);
+	rc = put_entry(buf, sizeof(u32), 1, fp);
+	if (rc)
+		return rc;
+
+	for (i = 0; i < list->len; i++) {
+		rc = avtab_write_item(p, list->nodes[i], fp);
+		if (rc)
+			return rc;
+	}
+
+	return 0;
+}
+
+static int cond_write_node(struct policydb *p, struct cond_node *node,
+		    struct policy_file *fp)
+{
+	__le32 buf[2];
+	int rc;
+	u32 i;
+
+	buf[0] = cpu_to_le32(node->cur_state);
+	rc = put_entry(buf, sizeof(u32), 1, fp);
+	if (rc)
+		return rc;
+
+	buf[0] = cpu_to_le32(node->expr.len);
+	rc = put_entry(buf, sizeof(u32), 1, fp);
+	if (rc)
+		return rc;
+
+	for (i = 0; i < node->expr.len; i++) {
+		buf[0] = cpu_to_le32(node->expr.nodes[i].expr_type);
+		buf[1] = cpu_to_le32(node->expr.nodes[i].boolean);
+		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, void *fp)
+{
+	u32 i;
+	__le32 buf[1];
+	int rc;
+
+	buf[0] = cpu_to_le32(p->cond_list_len);
+	rc = put_entry(buf, sizeof(u32), 1, fp);
+	if (rc)
+		return rc;
+
+	for (i = 0; i < p->cond_list_len; i++) {
+		rc = cond_write_node(p, &p->cond_list[i], fp);
+		if (rc)
+			return rc;
+	}
+
+	return 0;
+}
+
+void cond_compute_xperms(struct avtab *ctab, struct avtab_key *key,
+		struct extended_perms_decision *xpermd)
+{
+	struct avtab_node *node;
+
+	if (!ctab || !key || !xpermd)
+		return;
+
+	for (node = avtab_search_node(ctab, key); node;
+			node = avtab_search_node_next(node, key->specified)) {
+		if (node->key.specified & AVTAB_ENABLED)
+			services_compute_xperms_decision(xpermd, node);
+	}
+}
+/* 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 extended_perms *xperms)
+{
+	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.u.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.u.data;
+		if ((u16)(AVTAB_AUDITALLOW|AVTAB_ENABLED) ==
+		    (node->key.specified & (AVTAB_AUDITALLOW|AVTAB_ENABLED)))
+			avd->auditallow |= node->datum.u.data;
+		if (xperms && (node->key.specified & AVTAB_ENABLED) &&
+				(node->key.specified & AVTAB_XPERMS))
+			services_compute_xperms_drivers(xperms, node);
+	}
+}
+
+static int cond_dup_av_list(struct cond_av_list *new,
+			struct cond_av_list *orig,
+			struct avtab *avtab)
+{
+	u32 i;
+
+	memset(new, 0, sizeof(*new));
+
+	new->nodes = kcalloc(orig->len, sizeof(*new->nodes), GFP_KERNEL);
+	if (!new->nodes)
+		return -ENOMEM;
+
+	for (i = 0; i < orig->len; i++) {
+		new->nodes[i] = avtab_insert_nonunique(avtab,
+						       &orig->nodes[i]->key,
+						       &orig->nodes[i]->datum);
+		if (!new->nodes[i])
+			return -ENOMEM;
+		new->len++;
+	}
+
+	return 0;
+}
+
+static int duplicate_policydb_cond_list(struct policydb *newp,
+					struct policydb *origp)
+{
+	int rc;
+	u32 i;
+
+	rc = avtab_alloc_dup(&newp->te_cond_avtab, &origp->te_cond_avtab);
+	if (rc)
+		return rc;
+
+	newp->cond_list_len = 0;
+	newp->cond_list = kcalloc(origp->cond_list_len,
+				sizeof(*newp->cond_list),
+				GFP_KERNEL);
+	if (!newp->cond_list)
+		goto error;
+
+	for (i = 0; i < origp->cond_list_len; i++) {
+		struct cond_node *newn = &newp->cond_list[i];
+		struct cond_node *orign = &origp->cond_list[i];
+
+		newp->cond_list_len++;
+
+		newn->cur_state = orign->cur_state;
+		newn->expr.nodes = kmemdup(orign->expr.nodes,
+				orign->expr.len * sizeof(*orign->expr.nodes),
+				GFP_KERNEL);
+		if (!newn->expr.nodes)
+			goto error;
+
+		newn->expr.len = orign->expr.len;
+
+		rc = cond_dup_av_list(&newn->true_list, &orign->true_list,
+				&newp->te_cond_avtab);
+		if (rc)
+			goto error;
+
+		rc = cond_dup_av_list(&newn->false_list, &orign->false_list,
+				&newp->te_cond_avtab);
+		if (rc)
+			goto error;
+	}
+
+	return 0;
+
+error:
+	avtab_destroy(&newp->te_cond_avtab);
+	cond_list_destroy(newp);
+	return -ENOMEM;
+}
+
+static int cond_bools_destroy(void *key, void *datum, void *args)
+{
+	/* key was not copied so no need to free here */
+	kfree(datum);
+	return 0;
+}
+
+static int cond_bools_copy(struct hashtab_node *new, struct hashtab_node *orig, void *args)
+{
+	struct cond_bool_datum *datum;
+
+	datum = kmemdup(orig->datum, sizeof(struct cond_bool_datum),
+			GFP_KERNEL);
+	if (!datum)
+		return -ENOMEM;
+
+	new->key = orig->key; /* No need to copy, never modified */
+	new->datum = datum;
+	return 0;
+}
+
+static int cond_bools_index(void *key, void *datum, void *args)
+{
+	struct cond_bool_datum *booldatum, **cond_bool_array;
+
+	booldatum = datum;
+	cond_bool_array = args;
+	cond_bool_array[booldatum->value - 1] = booldatum;
+
+	return 0;
+}
+
+static int duplicate_policydb_bools(struct policydb *newdb,
+				struct policydb *orig)
+{
+	struct cond_bool_datum **cond_bool_array;
+	int rc;
+
+	cond_bool_array = kmalloc_array(orig->p_bools.nprim,
+					sizeof(*orig->bool_val_to_struct),
+					GFP_KERNEL);
+	if (!cond_bool_array)
+		return -ENOMEM;
+
+	rc = hashtab_duplicate(&newdb->p_bools.table, &orig->p_bools.table,
+			cond_bools_copy, cond_bools_destroy, NULL);
+	if (rc) {
+		kfree(cond_bool_array);
+		return -ENOMEM;
+	}
+
+	hashtab_map(&newdb->p_bools.table, cond_bools_index, cond_bool_array);
+	newdb->bool_val_to_struct = cond_bool_array;
+
+	newdb->p_bools.nprim = orig->p_bools.nprim;
+
+	return 0;
+}
+
+void cond_policydb_destroy_dup(struct policydb *p)
+{
+	hashtab_map(&p->p_bools.table, cond_bools_destroy, NULL);
+	hashtab_destroy(&p->p_bools.table);
+	cond_policydb_destroy(p);
+}
+
+int cond_policydb_dup(struct policydb *new, struct policydb *orig)
+{
+	cond_policydb_init(new);
+
+	if (duplicate_policydb_bools(new, orig))
+		return -ENOMEM;
+
+	if (duplicate_policydb_cond_list(new, orig)) {
+		cond_policydb_destroy_dup(new);
+		return -ENOMEM;
+	}
+
+	return 0;
+}