upstream commit

Check for NULL argument to sshkey_read.  Patch from
jjelen at redhat.com via bz#2687, ok djm@

Upstream-ID: c2d00c2ea50c4861d271d0a586f925cc64a87e0e
diff --git a/sshkey.c b/sshkey.c
index 85fd1bd..06e11c6 100644
--- a/sshkey.c
+++ b/sshkey.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: sshkey.c,v 1.43 2017/02/17 02:31:14 dtucker Exp $ */
+/* $OpenBSD: sshkey.c,v 1.44 2017/03/10 03:48:57 dtucker Exp $ */
 /*
  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
  * Copyright (c) 2008 Alexander von Gernler.  All rights reserved.
@@ -1239,6 +1239,9 @@
 	u_long bits;
 #endif /* WITH_SSH1 */
 
+	if (ret == NULL)
+		return SSH_ERR_INVALID_ARGUMENT;
+
 	cp = *cpp;
 
 	switch (ret->type) {