commit 77014cf7f9bde4925afeed52b7bf676d5f5b4285
author Han-Wen Nienhuys <hanwen@google.com> Tue Jan 31 18:37:52 2017 +0100
committer Han-Wen Nienhuys <hanwen@google.com> Mon Feb 06 10:12:19 2017 +0000
tree e1643a57a1f5b49ccdd55c300b75f5f345d612b0
parent bed12803fa9663d7aa2c2346b0c634ad2dcd43b7

ssh: prevent double kex at connection start, 2nd try

The previous attempt would fail in the following scenario:

* select picks "first" kex from requestKex

* read loop receives a remote kex, posts on requestKex (which is now
  empty) [*] for sending out a response, and sends pendingKex on startKex.

* select picks pendingKex from startKex, and proceeds to run the key
  exchange.

* the posting on requestKex in [*] now triggers a second key exchange.

Fixes #18861. 

Change-Id: I443e82f1d04c7f17d1485fdb87072b9feec26aa8
Reviewed-on: https://go-review.googlesource.com/36055
Run-TryBot: Han-Wen Nienhuys <hanwen@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Han-Wen Nienhuys <hanwen@google.com>