From db2790b6c76784951ecf7f5571be7803d018226b Mon Sep 17 00:00:00 2001
From: eric <eric@openbsd.org>
Date: Mon, 17 Dec 2018 08:56:31 +0000
Subject: [PATCH] set the return pointer to NULL when receiving a 0-sized data.

ok gilles
---
 usr.sbin/smtpd/mproc.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/usr.sbin/smtpd/mproc.c b/usr.sbin/smtpd/mproc.c
index f1175f74b06..d5a934d4800 100644
--- a/usr.sbin/smtpd/mproc.c
+++ b/usr.sbin/smtpd/mproc.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: mproc.c,v 1.31 2018/12/13 17:08:10 gilles Exp $	*/
+/*	$OpenBSD: mproc.c,v 1.32 2018/12/17 08:56:31 eric Exp $	*/
 
 /*
  * Copyright (c) 2012 Eric Faurot <eric@faurot.net>
@@ -583,6 +583,11 @@ m_get_data(struct msg *m, const void **data, size_t *sz)
 {
 	m_get_size(m, sz);
 
+	if (*sz == 0) {
+		*data = NULL;
+		return;
+	}
+
 	if (m->pos + *sz > m->end)
 		m_error("msg too short");
 
-- 
2.20.1