commit 967226a1bdde59ea137e8f0df871854ff7b91366
author djm@openbsd.org <djm@openbsd.org> Sat Aug 04 00:55:06 2018 +0000
committer Damien Miller <djm@mindrot.org> Mon Aug 06 11:07:17 2018 +1000
tree 59392d040b5d6f8762955db701bde5ef2f075b88
parent 74287f5df9966a0648b4a68417451dd18f079ab8

upstream: invalidate dh->priv_key after freeing it in error path;

avoids unlikely double-free later. Reported by Viktor Dukhovni via
https://github.com/openssh/openssh-portable/pull/96 feedback jsing@ tb@

OpenBSD-Commit-ID: e317eb17c3e05500ae851f279ef6486f0457c805

dh.c

diff --git a/dh.c b/dh.c
index faa19a1..ac8d5a0 100644
--- a/dh.c
+++ b/dh.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: dh.c,v 1.65 2018/06/26 11:23:59 millert Exp $ */
+/* $OpenBSD: dh.c,v 1.66 2018/08/04 00:55:06 djm Exp $ */
 /*
  * Copyright (c) 2000 Niels Provos.  All rights reserved.
  *
@@ -279,6 +279,7 @@
 	if (DH_generate_key(dh) == 0 ||
 	    !dh_pub_is_valid(dh, dh->pub_key)) {
 		BN_clear_free(dh->priv_key);
+		dh->priv_key = NULL;
 		return SSH_ERR_LIBCRYPTO_ERROR;
 	}
 	return 0;