1 files changed, 3 insertions, 0 deletions
diff --git a/src/shared/ptyfwd.c b/src/shared/ptyfwd.c
index 6ffe86e..21cfe1d 100644
--- a/src/shared/ptyfwd.c
+++ b/src/shared/ptyfwd.c
@@ -406,6 +406,9 @@ int pty_forward_new(
         struct winsize ws;
         int r;
 
+        assert(master >= 0);
+        assert(ret);
+
         f = new(PTYForward, 1);
         if (!f)
                 return -ENOMEM;