From 0ef8f4071a40ed116fa07dcfca2ce195d91e081c Mon Sep 17 00:00:00 2001
From: jacob <jacob@cda61777-01e9-0310-a592-d414129be87e>
Date: Wed, 21 Nov 2001 22:48:20 +0000
Subject: [PATCH] Primitive protection against SSH2 not actually agreeing a
 cipher in either direction.

git-svn-id: svn://svn.tartarus.org/sgt/putty@1394 cda61777-01e9-0310-a592-d414129be87e
---
 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)) {
-- 
2.11.0