3 files changed, 37 insertions, 26 deletions

diff --git a/names.c b/names.c
index daa13b91e0b..b1702839588 100644
--- a/names.c
+++ b/names.c
@@ -691,10 +691,15 @@ static int kdbus_name_list_write(struct kdbus_conn *conn,
 		 * Note that policy DBs instanciated along with connections
 		 * don't have SEE rules, so it's sufficient to check the
 		 * endpoint's database.
+		 *
+		 * The lock for the policy db is held across all calls of
+		 * kdbus_name_list_all(), so the entries in both writing
+		 * and non-writing runs of kdbus_name_list_write() are the
+		 * same.
 		 */
 		if (conn->ep->policy_db &&
-		    kdbus_policy_check_see_access(conn->ep->policy_db,
-						  e->name) < 0)
+		    kdbus_policy_check_see_access_unlocked(conn->ep->policy_db,
+							   e->name) < 0)
 				return 0;
 	}
 
@@ -812,13 +817,19 @@ int kdbus_cmd_name_list(struct kdbus_name_registry *reg,
 			struct kdbus_conn *conn,
 			struct kdbus_cmd_name_list *cmd)
 {
+	struct kdbus_policy_db *policy_db;
 	struct kdbus_name_list list = {};
 	size_t size, off, pos;
 	int ret;
 
+	policy_db = conn->ep->policy_db;
+
 	mutex_lock(&conn->bus->lock);
 	mutex_lock(&reg->entries_lock);
 
+	if (policy_db)
+		mutex_lock(&policy_db->entries_lock);
+
 	/* size of header */
 	size = sizeof(struct kdbus_name_list);
 
@@ -853,6 +864,9 @@ exit_pool_free:
 	if (ret < 0)
 		kdbus_pool_free_range(conn->pool, off);
 exit_unlock:
+	if (policy_db)
+		mutex_unlock(&policy_db->entries_lock);
+
 	mutex_unlock(&reg->entries_lock);
 	mutex_unlock(&conn->bus->lock);
 
diff --git a/policy.c b/policy.c
index 3a04024c681..0bc0a9999b6 100644
--- a/policy.c
+++ b/policy.c
@@ -30,20 +30,6 @@
 #define KDBUS_POLICY_HASH_SIZE	64
 
 /**
- * struct kdbus_policy_db - policy database
- * @entries_hash:	Hashtable of entries
- * @send_access_hash:	Hashtable of send access elements
- * @entries_lock:	Mutex to protect the database's access entries
- * @cache_lock:		Mutex to protect the database's cache
- */
-struct kdbus_policy_db {
-	DECLARE_HASHTABLE(entries_hash, 6);
-	DECLARE_HASHTABLE(send_access_hash, 6);
-	struct mutex entries_lock;
-	struct mutex cache_lock;
-};
-
-/**
  * struct kdbus_policy_db_cache_entry - a cached entry
  * @conn_a:		Connection A
  * @conn_b:		Connection B
@@ -379,21 +365,18 @@ exit_unlock_entries:
  *
  * Return: 0 if permission to see the name is granted, -EPERM otherwise
  */
-int kdbus_policy_check_see_access(struct kdbus_policy_db *db,
-				  const char *name)
+int kdbus_policy_check_see_access_unlocked(struct kdbus_policy_db *db,
+					   const char *name)
 {
 	struct kdbus_policy_db_entry *e;
-	int ret = -EPERM;
 	u32 hash;
 
 	hash = kdbus_str_hash(name);
-	mutex_lock(&db->entries_lock);
 	e = __kdbus_policy_lookup(db, name, hash, true);
 	if (kdbus_policy_check_access(e, KDBUS_POLICY_SEE))
-		ret = 0;
-	mutex_unlock(&db->entries_lock);
+		return 0;
 
-	return ret;
+	return -EPERM;
 }
 
 static void __kdbus_policy_remove_owner(struct kdbus_policy_db *db,
diff --git a/policy.h b/policy.h
index eceecdc6c13..380c06f14aa 100644
--- a/policy.h
+++ b/policy.h
@@ -14,12 +14,26 @@
 #define __KDBUS_POLICY_H
 
 struct kdbus_conn;
-struct kdbus_policy_db;
+
+/**
+ * struct kdbus_policy_db - policy database
+ * @entries_hash:	Hashtable of entries
+ * @send_access_hash:	Hashtable of send access elements
+ * @entries_lock:	Mutex to protect the database's access entries
+ * @cache_lock:		Mutex to protect the database's cache
+ */
+struct kdbus_policy_db {
+	DECLARE_HASHTABLE(entries_hash, 6);
+	DECLARE_HASHTABLE(send_access_hash, 6);
+	struct mutex entries_lock;
+	struct mutex cache_lock;
+};
 
 int kdbus_policy_db_new(struct kdbus_policy_db **db);
 void kdbus_policy_db_free(struct kdbus_policy_db *db);
-int kdbus_policy_check_see_access(struct kdbus_policy_db *db,
-				  const char *name);
+
+int kdbus_policy_check_see_access_unlocked(struct kdbus_policy_db *db,
+					   const char *name);
 int kdbus_policy_check_talk_access(struct kdbus_policy_db *db,
 				   struct kdbus_conn *conn_src,
 				   struct kdbus_conn *conn_dst);