diff --git a/sm/certdump.c b/sm/certdump.c
index 9567c67f5..ef60358d7 100644
--- a/sm/certdump.c
+++ b/sm/certdump.c
@@ -658,6 +658,10 @@ format_name_writer (void *cookie, const void *buffer, size_t size)
   struct format_name_cookie *c = cookie;
   char *p;
 
+  /* FIXME: Replace the whole thing using es_fopenmem based code.  */
+  if (!buffer)  /* Flush. */
+    return 0;  /* (Actually we could use SIZE because that should be 0 too.)  */
+
   if (!c->buffer)
     {
       p = xtrymalloc (size + 1 + 1);