upstream commit

return failure rather than fatal() for more cases during
mux negotiations. Causes the session to fall back to a non-mux connection if
they occur. bz#2707 ok dtucker@

Upstream-ID: d2a7892f464d434e1f615334a1c9d0cdb83b29ab

1 files changed, 20 insertions, 10 deletions

diff --git a/mux.c b/mux.c
index 2d6639c5c..3dde4da40 100644
--- a/mux.c
+++ b/mux.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: mux.c,v 1.64 2017/01/21 11:32:04 guenther Exp $ */
+/* $OpenBSD: mux.c,v 1.65 2017/06/09 06:47:13 djm Exp $ */
 /*
  * Copyright (c) 2002-2008 Damien Miller <djm@openbsd.org>
  *
@@ -1570,31 +1570,38 @@ mux_client_hello_exchange(int fd)
 {
         Buffer m;
         u_int type, ver;
+        int ret = -1;
 
         buffer_init(&m);
         buffer_put_int(&m, MUX_MSG_HELLO);
         buffer_put_int(&m, SSHMUX_VER);
         /* no extensions */
 
-        if (mux_client_write_packet(fd, &m) != 0)
-                fatal("%s: write packet: %s", __func__, strerror(errno));
+        if (mux_client_write_packet(fd, &m) != 0) {
+                debug("%s: write packet: %s", __func__, strerror(errno));
+                goto out;
+        }
 
         buffer_clear(&m);
 
         /* Read their HELLO */
         if (mux_client_read_packet(fd, &m) != 0) {
-                buffer_free(&m);
-                return -1;
+                debug("%s: read packet failed", __func__);
+                goto out;
         }
 
         type = buffer_get_int(&m);
-        if (type != MUX_MSG_HELLO)
-                fatal("%s: expected HELLO (%u) received %u",
+        if (type != MUX_MSG_HELLO) {
+                error("%s: expected HELLO (%u) received %u",
                     __func__, MUX_MSG_HELLO, type);
+                goto out;
+        }
         ver = buffer_get_int(&m);
-        if (ver != SSHMUX_VER)
-                fatal("Unsupported multiplexing protocol version %d "
+        if (ver != SSHMUX_VER) {
+                error("Unsupported multiplexing protocol version %d "
                     "(expected %d)", ver, SSHMUX_VER);
+                goto out;
+        }
         debug2("%s: master version %u", __func__, ver);
         /* No extensions are presently defined */
         while (buffer_len(&m) > 0) {
@@ -1605,8 +1612,11 @@ mux_client_hello_exchange(int fd)
                 free(name);
                 free(value);
         }
+        /* success */
+        ret = 0;
+ out:
         buffer_free(&m);
-        return 0;
+        return ret;
 }
 
 static u_int