simon-git: putty (main): Simon Tatham

[Commits to Tartarus hosted VCS]

TL;DR:
  c62b7229 Bug workaround to delay sending our SSH greeting.

Repository:     https://git.tartarus.org/simon/putty.git
On the web:     https://git.tartarus.org/?p=simon/putty.git
Branch updated: main
Committer:      Simon Tatham <anakin at pobox.com>
Date:           2021-08-14 11:48:39

commit c62b7229c1928f875c77108db50ab356c7f59001
web diff https://git.tartarus.org/?p=simon/putty.git;a=commitdiff;h=c62b7229c1928f875c77108db50ab356c7f59001;hp=dfb252d161e9dc7861c19da0dce9e565de321efd
Author: Simon Tatham <anakin at pobox.com>
Date:   Sat Aug 14 10:56:20 2021 +0100

    Bug workaround to delay sending our SSH greeting.
    
    Ian Jackson recently tried to use the recipe in the psusan manpage for
    talking to UML, and found that the connection was not successfully set
    up, because at some point during startup, UML read the SSH greeting
    (ok, the bare-ssh-connection greeting) from its input fd and threw it
    away. So by the time psusan was run by the guest init process, the
    greeting wasn't there to be read.
    
    Ian's report: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=991958
    
    I was also able to reproduce this locally, which makes me wonder why I
    _didn't_ notice it when I originally wrote that part of the psusan man
    page. It worked for me before, honest! But now it doesn't.
    
    Anyway. The ssh verstring module already has a mode switch to decide
    whether we ought to send our greeting before or after waiting for the
    other side's greeting (because that decision varies between client and
    server, and between SSH-1 and SSH-2). So it's easy to implement an
    override that forces it to 'wait for the server greeting first'.
    
    I've added this as yet another bug workaround flag. But unlike all the
    others, it can't be autodetected from the server's version string,
    because, of course, we have to act on it _before_ seeing the server's
    greeting and version string! So it's a manual-only flag.
    
    However, I've mentioned it in the UML section of the psusan man page,
    since that's the place where I _know_ people are likely to need to use
    this flag.

 config.c           | 38 ++++++++++++++++++++++++++++++++++++++
 doc/config.but     | 28 +++++++++++++++++++++++++++-
 doc/man-psusan.but | 16 ++++++++++++----
 putty.h            |  1 +
 settings.c         |  2 ++
 ssh/verstring.c    |  8 ++++++++
 windows/help.h     |  1 +
 7 files changed, 89 insertions(+), 5 deletions(-)