upstream commit

apparently memcpy(x, NULL, 0) is undefined behaviour
 according to C99 (cf. sections 7.21.1 and 7.1.4), so check skip memcpy calls
 when length==0; ok markus@

1 files changed, 3 insertions, 2 deletions

diff --git a/sshbuf-getput-crypto.c b/sshbuf-getput-crypto.c
index 74351d3e5..7fad28bb7 100644
--- a/sshbuf-getput-crypto.c
+++ b/sshbuf-getput-crypto.c
@@ -1,4 +1,4 @@
-/*      $OpenBSD: sshbuf-getput-crypto.c,v 1.2 2014/06/18 15:42:09 naddy Exp $  */
+/*      $OpenBSD: sshbuf-getput-crypto.c,v 1.3 2015/01/12 15:18:07 djm Exp $    */
 /*
  * Copyright (c) 2011 Damien Miller
  *
@@ -195,7 +195,8 @@ sshbuf_put_bignum1(struct sshbuf *buf, const BIGNUM *v)
                 return r;
         }
         POKE_U16(dp, len_bits);
-        memcpy(dp + 2, d, len_bytes);
+        if (len_bytes != 0)
+                memcpy(dp + 2, d, len_bytes);
         bzero(d, sizeof(d));
         return 0;
 }