Index: sys/ufs/ffs/ffs_alloc.c
===================================================================
--- sys/ufs/ffs/ffs_alloc.c
+++ sys/ufs/ffs/ffs_alloc.c
@@ -3211,9 +3211,9 @@
 	cap_rights_t rights;
 	int filetype, error;
 
-	if (req->newlen > sizeof cmd)
+	if (req->newptr == NULL || req->newlen > sizeof(cmd))
 		return (EBADRPC);
-	if ((error = SYSCTL_IN(req, &cmd, sizeof cmd)) != 0)
+	if ((error = SYSCTL_IN(req, &cmd, sizeof(cmd))) != 0)
 		return (error);
 	if (cmd.version != FFS_CMD_VERSION)
 		return (ERPCMISMATCH);