From dd4bfacd9a3bcc3350259a6665813cd2aa72fb90 Mon Sep 17 00:00:00 2001
From: Jacob Nevins <jacobn@chiark.greenend.org.uk>
Date: Wed, 21 Nov 2001 22:48:20 +0000
Subject: [PATCH] Primitive protection against SSH2 not actually agreeing a
 cipher in either direction.

[originally from svn r1394]
---
 ssh.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/ssh.c b/ssh.c
index 7943d071..ef573d42 100644
--- a/ssh.c
+++ b/ssh.c
@@ -3353,6 +3353,11 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
 	    break;
 	}
     }
+    if (!cscipher_tobe) {
+	bombout(("Couldn't agree a client-to-server cipher (available: %s)", str));
+	crReturn(0);
+    }
+
     ssh2_pkt_getstring(&str, &len);    /* server->client cipher */
     warn = 0;
     for (i = 0; i < n_preferred_ciphers; i++) {
@@ -3373,6 +3378,11 @@ static int do_ssh2_transport(unsigned char *in, int inlen, int ispkt)
 	    break;
 	}
     }
+    if (!sccipher_tobe) {
+	bombout(("Couldn't agree a server-to-client cipher (available: %s)", str));
+	crReturn(0);
+    }
+
     ssh2_pkt_getstring(&str, &len);    /* client->server mac */
     for (i = 0; i < nmacs; i++) {
 	if (in_commasep_string(maclist[i]->name, str, len)) {