1 files changed, 24 insertions, 7 deletions

diff --git a/kex.c b/kex.c
index dbc55ef7e..5e8b51394 100644
--- a/kex.c
+++ b/kex.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: kex.c,v 1.106 2015/04/17 13:25:52 djm Exp $ */
+/* $OpenBSD: kex.c,v 1.107 2015/07/29 04:43:06 djm Exp $ */
 /*
  * Copyright (c) 2000, 2001 Markus Friedl.  All rights reserved.
  *
@@ -448,6 +448,7 @@ kex_free(struct kex *kex)
         free(kex->session_id);
         free(kex->client_version_string);
         free(kex->server_version_string);
+        free(kex->failed_choice);
         free(kex);
 }
 
@@ -626,17 +627,26 @@ kex_choose_conf(struct ssh *ssh)
                 nmac  = ctos ? PROPOSAL_MAC_ALGS_CTOS  : PROPOSAL_MAC_ALGS_STOC;
                 ncomp = ctos ? PROPOSAL_COMP_ALGS_CTOS : PROPOSAL_COMP_ALGS_STOC;
                 if ((r = choose_enc(&newkeys->enc, cprop[nenc],
-                    sprop[nenc])) != 0)
+                    sprop[nenc])) != 0) {
+                        kex->failed_choice = peer[nenc];
+                        peer[nenc] = NULL;
                         goto out;
+                }
                 authlen = cipher_authlen(newkeys->enc.cipher);
                 /* ignore mac for authenticated encryption */
                 if (authlen == 0 &&
                     (r = choose_mac(ssh, &newkeys->mac, cprop[nmac],
-                    sprop[nmac])) != 0)
+                    sprop[nmac])) != 0) {
+                        kex->failed_choice = peer[nmac];
+                        peer[nmac] = NULL;
                         goto out;
+                }
                 if ((r = choose_comp(&newkeys->comp, cprop[ncomp],
-                    sprop[ncomp])) != 0)
+                    sprop[ncomp])) != 0) {
+                        kex->failed_choice = peer[ncomp];
+                        peer[ncomp] = NULL;
                         goto out;
+                }
                 debug("kex: %s %s %s %s",
                     ctos ? "client->server" : "server->client",
                     newkeys->enc.name,
@@ -644,10 +654,17 @@ kex_choose_conf(struct ssh *ssh)
                     newkeys->comp.name);
         }
         if ((r = choose_kex(kex, cprop[PROPOSAL_KEX_ALGS],
-            sprop[PROPOSAL_KEX_ALGS])) != 0 ||
-            (r = choose_hostkeyalg(kex, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS],
-            sprop[PROPOSAL_SERVER_HOST_KEY_ALGS])) != 0)
+            sprop[PROPOSAL_KEX_ALGS])) != 0) {
+                kex->failed_choice = peer[PROPOSAL_KEX_ALGS];
+                peer[PROPOSAL_KEX_ALGS] = NULL;
                 goto out;
+        }
+        if ((r = choose_hostkeyalg(kex, cprop[PROPOSAL_SERVER_HOST_KEY_ALGS],
+            sprop[PROPOSAL_SERVER_HOST_KEY_ALGS])) != 0) {
+                kex->failed_choice = cprop[PROPOSAL_SERVER_HOST_KEY_ALGS];
+                cprop[PROPOSAL_SERVER_HOST_KEY_ALGS] = NULL;
+                goto out;
+        }
         need = dh_need = 0;
         for (mode = 0; mode < MODE_MAX; mode++) {
                 newkeys = kex->newkeys[mode];