From eac342a1aa4fcedd309607896bd94166914a21b4 Mon Sep 17 00:00:00 2001
From: dtucker <dtucker@openbsd.org>
Date: Fri, 16 Feb 2018 04:43:11 +0000
Subject: [PATCH] Don't send IUTF8 to servers that don't like them.

Some SSH servers eg "ConfD" drop the connection if the client sends the
new IUTF8 (RFC8160) terminal mode even if it's not set.  Add a bug bit
for such servers and avoid sending IUTF8 to them.  ok djm@
---
 usr.bin/ssh/compat.c   |  4 +++-
 usr.bin/ssh/compat.h   |  4 ++--
 usr.bin/ssh/ttymodes.c | 13 ++++++++++---
 3 files changed, 15 insertions(+), 6 deletions(-)

diff --git a/usr.bin/ssh/compat.c b/usr.bin/ssh/compat.c
index eea0741ad8d..1fcf84a0588 100644
--- a/usr.bin/ssh/compat.c
+++ b/usr.bin/ssh/compat.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: compat.c,v 1.105 2018/01/23 05:27:21 djm Exp $ */
+/* $OpenBSD: compat.c,v 1.106 2018/02/16 04:43:11 dtucker Exp $ */
 /*
  * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl.  All rights reserved.
  *
@@ -124,6 +124,8 @@ compat_datafellows(const char *version)
 		  "WinSCP_release_5.7.3,"
 		  "WinSCP_release_5.7.4",
 					SSH_OLD_DHGEX },
+		{ "ConfD-*",
+					SSH_BUG_UTF8TTYMODE },
 		{ NULL,			0 }
 	};
 
diff --git a/usr.bin/ssh/compat.h b/usr.bin/ssh/compat.h
index 246e6ee4c20..4fee3495a5a 100644
--- a/usr.bin/ssh/compat.h
+++ b/usr.bin/ssh/compat.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: compat.h,v 1.50 2018/01/23 05:27:21 djm Exp $ */
+/* $OpenBSD: compat.h,v 1.51 2018/02/16 04:43:11 dtucker Exp $ */
 
 /*
  * Copyright (c) 1999, 2000, 2001 Markus Friedl.  All rights reserved.
@@ -32,7 +32,7 @@
 #define	SSH_PROTO_1_PREFERRED	0x02
 #define	SSH_PROTO_2		0x04
 
-/* #define unused		0x00000001 */
+#define SSH_BUG_UTF8TTYMODE	0x00000001
 /* #define unused		0x00000002 */
 /* #define unused		0x00000004 */
 /* #define unused		0x00000008 */
diff --git a/usr.bin/ssh/ttymodes.c b/usr.bin/ssh/ttymodes.c
index 09729ba04f8..65e0888a11a 100644
--- a/usr.bin/ssh/ttymodes.c
+++ b/usr.bin/ssh/ttymodes.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: ttymodes.c,v 1.32 2017/04/30 23:26:54 djm Exp $ */
+/* $OpenBSD: ttymodes.c,v 1.33 2018/02/16 04:43:11 dtucker Exp $ */
 /*
  * Author: Tatu Ylonen <ylo@cs.hut.fi>
  * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
@@ -54,6 +54,7 @@
 #include "log.h"
 #include "compat.h"
 #include "buffer.h"
+#include "compat.h"
 
 #define TTY_OP_END		0
 /*
@@ -280,9 +281,15 @@ tty_make_modes(int fd, struct termios *tiop)
 	buffer_put_char(&buf, OP); \
 	buffer_put_int(&buf, tio.c_cc[NAME]);
 
+#define SSH_TTYMODE_IUTF8 42  /* for SSH_BUG_UTF8TTYMODE */
+
 #define TTYMODE(NAME, FIELD, OP) \
-	buffer_put_char(&buf, OP); \
-	buffer_put_int(&buf, ((tio.FIELD & NAME) != 0));
+	if (OP == SSH_TTYMODE_IUTF8 && (datafellows & SSH_BUG_UTF8TTYMODE)) { \
+		debug3("%s: SSH_BUG_UTF8TTYMODE", __func__); \
+	} else { \
+		buffer_put_char(&buf, OP); \
+		buffer_put_int(&buf, ((tio.FIELD & NAME) != 0)); \
+	}
 
 #include "ttymodes.h"
 
-- 
2.20.1