From 3f0f6d2013dd19afa2033d7f33961ff1ed90000f Mon Sep 17 00:00:00 2001
From: Simon Tatham <anakin@pobox.com>
Date: Tue, 9 Oct 2018 18:07:52 +0100
Subject: [PATCH] Missing error message when loading a private key file.

If the file is empty, or otherwise fails to start with a recognised
'PuTTY-User-Key-File' header line, we forgot to fill in the error
message before returning failure, leading to a null pointer
dereference.
---
 sshpubk.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/sshpubk.c b/sshpubk.c
index 2144bc2c..510eb585 100644
--- a/sshpubk.c
+++ b/sshpubk.c
@@ -612,8 +612,10 @@ struct ssh2_userkey *ssh2_load_userkey(const Filename *filename,
     }
 
     /* Read the first header line which contains the key type. */
-    if (!read_header(fp, header))
+    if (!read_header(fp, header)) {
+	error = "no header line found in key file";
 	goto error;
+    }
     if (0 == strcmp(header, "PuTTY-User-Key-File-2")) {
 	old_fmt = 0;
     } else if (0 == strcmp(header, "PuTTY-User-Key-File-1")) {