From ee5769f31fc5bef0c0f5f6977523918af892fa3b Mon Sep 17 00:00:00 2001
From: Matt Johnston <matt@ucc.asn.au>
Date: Thu, 25 May 2017 00:09:40 +0800
Subject: [PATCH] avoid NULL argument to base64 decode

--HG--
branch : fuzz
---
 signkey.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/signkey.c b/signkey.c
index 3d78e35..19a2c08 100644
--- a/signkey.c
+++ b/signkey.c
@@ -577,6 +577,10 @@ int cmp_base64_key(const unsigned char* keyblob, unsigned int keybloblen,
 
 	/* now we have the actual data */
 	len = line->len - line->pos;
+	if (len == 0) {
+		/* base64_decode doesn't like NULL argument */
+		return DROPBEAR_FAILURE;
+	}
 	decodekeylen = len * 2; /* big to be safe */
 	decodekey = buf_new(decodekeylen);