set the return pointer to NULL when receiving a 0-sized data.

ok gilles

diff --git a/usr.sbin/smtpd/mproc.c b/usr.sbin/smtpd/mproc.c
index f1175f7..d5a934d 100644 (file)
--- 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");