From 146c420d29d055cc75c8606327a1cf8439fe3a08 Mon Sep 17 00:00:00 2001 From: "djm@openbsd.org" Date: Mon, 1 Jul 2024 04:31:17 +0000 Subject: [PATCH] upstream: when sending ObscureKeystrokeTiming chaff packets, we can't rely on channel_did_enqueue to tell that there is data to send. This flag indicates that the channels code enqueued a packet on _this_ ppoll() iteration, not that data was enqueued in _any_ ppoll() iteration in the timeslice. ok markus@ OpenBSD-Commit-ID: 009b74fd2769b36b5284a0188ade182f00564136 --- clientloop.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/clientloop.c b/clientloop.c index 0b6f3c9be02..8ed8b1c3449 100644 --- a/clientloop.c +++ b/clientloop.c #@@ -1,4 +1,4 @@ #-/* $OpenBSD: clientloop.c,v 1.407 2024/05/17 06:42:04 jsg Exp $ */ #+/* $OpenBSD: clientloop.c,v 1.408 2024/07/01 04:31:17 djm Exp $ */ # /* # * Author: Tatu Ylonen # * Copyright (c) 1995 Tatu Ylonen , Espoo, Finland @@ -607,8 +607,9 @@ obfuscate_keystroke_timing(struct ssh *ssh, struct timespec *timeout, if (timespeccmp(&now, &chaff_until, >=)) { /* Stop if there have been no keystrokes for a while */ stop_reason = "chaff time expired"; - } else if (timespeccmp(&now, &next_interval, >=)) { - /* Otherwise if we were due to send, then send chaff */ + } else if (timespeccmp(&now, &next_interval, >=) && + !ssh_packet_have_data_to_write(ssh)) { + /* If due to send but have no data, then send chaff */ if (send_chaff(ssh)) nchaff++; }