openssh unix dev - Aug 2018 - OpenSSH 7.8p1 drops SSH connection with "Broken Pipe" IMMEDIATELY after successful login

Hi.

Environment:

  *   OS: Antergos Linux (Fully updated daily) (Running as a guest on VM).
  *   OpenSSH: 7.8p1

Description:
Immediately upon creating a successful SSH tunnel login, the connection is
dropped with the "packet_write_wait: Connection to X.X.X.X port 22: Broken
pipe" error.

I've verified the issue is due to OpenSSH 7.8p1 in the following ways:

  *   Use a different, older client (i.e. the Windows host machine's PuTTy
client, which I haven't updated god-knows-when).
  *   Downgrade the Antergos guest to OpenSSH 7.7p2

Both these case produced a working SSH connection.

Reproduce effort:

  *   Upgrade SSH client to OpenSSH 7.8p1
  *   Try to SSH into a server
     *   Some options:
     *   demo at test.rebex.net (use "password" for password)
     *   Git - any remote operation (i.e. pull, push, fetch, clone...)

The expected behavior is a consistent SSH connection.
The actual behavior is that immediately after the authentication is successful
the connection is dropped with "packet_write_wait: Connection to X.X.X.X
port 22: Broken pipe" error occurs, the connection is dropped (and no work
can be done, e.g. clone/push to Git remote repo).


________________________________
From: Ohad Frenkel <ohadfjunkbox at outlook.com>
Sent: 28 August 2018 21:30
To: openssh-unix-dev at mindrot.org
Subject: OpenSSH 7.8p1 drops SSH connection with "Broken Pipe"
IMMEDIATELY after successful login

Hi.

Environment:

  *   OS: Antergos Linux (Fully updated daily) (Running as a guest on VM).
  *   OpenSSH: 7.8p1

Description:
Immediately upon creating a successful SSH tunnel login, the connection is
dropped with the "packet_write_wait: Connection to X.X.X.X port 22: Broken
pipe" error.

I've verified the issue is due to OpenSSH 7.8p1 in the following ways:

  *   Use a different, older client (i.e. the Windows host machine's PuTTy
client, which I haven't updated god-knows-when).
  *   Downgrade the Antergos guest to OpenSSH 7.7p2

Both these case produced a working SSH connection.

Reproduce effort:

  *   Upgrade SSH client to OpenSSH 7.8p1
  *   Try to SSH into a server
     *   Some options:
     *   demo at test.rebex.net (use "password" for password)
     *   Git - any remote operation (i.e. pull, push, fetch, clone...)

The expected behavior is a consistent SSH connection.
The actual behavior is that immediately after the authentication is successful
the connection is dropped with "packet_write_wait: Connection to X.X.X.X
port 22: Broken pipe" error occurs, the connection is dropped (and no work
can be done, e.g. clone/push to Git remote repo).

Dear Ohad,

What virtualisation software are you using?

Kind regards,

Job


On Tue, Aug 28, 2018 at 9:36 PM, Ohad Frenkel <ohadfjunkbox at
outlook.com> wrote:
> Hi.
>
> Environment:
>
>   *   OS: Antergos Linux (Fully updated daily) (Running as a guest on VM).
>   *   OpenSSH: 7.8p1
>
> Description:
> Immediately upon creating a successful SSH tunnel login, the connection is
dropped with the "packet_write_wait: Connection to X.X.X.X port 22: Broken
pipe" error.
>
> I've verified the issue is due to OpenSSH 7.8p1 in the following ways:
>
>   *   Use a different, older client (i.e. the Windows host machine's
PuTTy client, which I haven't updated god-knows-when).
>   *   Downgrade the Antergos guest to OpenSSH 7.7p2
>
> Both these case produced a working SSH connection.
>
> Reproduce effort:
>
>   *   Upgrade SSH client to OpenSSH 7.8p1
>   *   Try to SSH into a server
>      *   Some options:
>      *   demo at test.rebex.net (use "password" for password)
>      *   Git - any remote operation (i.e. pull, push, fetch, clone...)
>
> The expected behavior is a consistent SSH connection.
> The actual behavior is that immediately after the authentication is
successful the connection is dropped with "packet_write_wait: Connection to
X.X.X.X port 22: Broken pipe" error occurs, the connection is dropped (and
no work can be done, e.g. clone/push to Git remote repo).
>
>
> ________________________________
> From: Ohad Frenkel <ohadfjunkbox at outlook.com>
> Sent: 28 August 2018 21:30
> To: openssh-unix-dev at mindrot.org
> Subject: OpenSSH 7.8p1 drops SSH connection with "Broken Pipe"
IMMEDIATELY after successful login
>
> Hi.
>
> Environment:
>
>   *   OS: Antergos Linux (Fully updated daily) (Running as a guest on VM).
>   *   OpenSSH: 7.8p1
>
> Description:
> Immediately upon creating a successful SSH tunnel login, the connection is
dropped with the "packet_write_wait: Connection to X.X.X.X port 22: Broken
pipe" error.
>
> I've verified the issue is due to OpenSSH 7.8p1 in the following ways:
>
>   *   Use a different, older client (i.e. the Windows host machine's
PuTTy client, which I haven't updated god-knows-when).
>   *   Downgrade the Antergos guest to OpenSSH 7.7p2
>
> Both these case produced a working SSH connection.
>
> Reproduce effort:
>
>   *   Upgrade SSH client to OpenSSH 7.8p1
>   *   Try to SSH into a server
>      *   Some options:
>      *   demo at test.rebex.net (use "password" for password)
>      *   Git - any remote operation (i.e. pull, push, fetch, clone...)
>
> The expected behavior is a consistent SSH connection.
> The actual behavior is that immediately after the authentication is
successful the connection is dropped with "packet_write_wait: Connection to
X.X.X.X port 22: Broken pipe" error occurs, the connection is dropped (and
no work can be done, e.g. clone/push to Git remote repo).
> _______________________________________________
> openssh-unix-dev mailing list
> openssh-unix-dev at mindrot.org
> https://lists.mindrot.org/mailman/listinfo/openssh-unix-dev

On 28 August 2018 at 13:36, Ohad Frenkel <ohadfjunkbox at outlook.com>
wrote:
>   *   OS: Antergos Linux (Fully updated daily) (Running as a guest on VM).
If the VM host is VMWare Fusion, see
https://lists.mindrot.org/pipermail/openssh-unix-dev/2018-August/037145.html
wherein it appears to have a bug in its networking stack that chokes
on the new default (valid) DSCP markings.  If so you can work around
it by overriding the defaults, but the problem is within VMWare (maybe
in general, or maybe just the Fusion product).

-- 
Darren Tucker (dtucker at dtucker.net)
GPG key 11EAA6FA / A86E 3E07 5B19 5880 E860  37F4 9357 ECEF 11EA A6FA (new)
    Good judgement comes with experience. Unfortunately, the experience
usually comes from bad judgement.

The virtualization is VMware Workstation 12.x, NOT Fusion.
Again, I'd like to point that downgrading to 7.7p2 "solved" the
issue and that I'm using the same virtualization software for ages (which
makes me disbelieve the issue lies with it).

I've seen the comment about zero-length passwords... I'm not techie
enough to understand the code there (or the technical explanation), but it is
true that my previous SSH keys were password-less (if that is the meaning of
"zero-length password").
I say "previous" because one of the first things I did, trying to
solve this on my end, was to assume the problem was with the keys and thus
generated a new set of keys, all of which have positive value of characters in
the password (which, by the way, did not solve the case. As I said, only
downgrading to 7.7p2 did the trick).
________________________________
From: Darren Tucker <dtucker at dtucker.net>
Sent: 28 August 2018 22:18
To: Ohad Frenkel
Cc: openssh-unix-dev at mindrot.org
Subject: Re: OpenSSH 7.8p1 drops SSH connection with "Broken Pipe"
IMMEDIATELY after successful login

On 28 August 2018 at 13:36, Ohad Frenkel <ohadfjunkbox at outlook.com>
wrote:
>   *   OS: Antergos Linux (Fully updated daily) (Running as a guest on VM).
If the VM host is VMWare Fusion, see
https://lists.mindrot.org/pipermail/openssh-unix-dev/2018-August/037145.html
wherein it appears to have a bug in its networking stack that chokes
on the new default (valid) DSCP markings.  If so you can work around
it by overriding the defaults, but the problem is within VMWare (maybe
in general, or maybe just the Fusion product).

--
Darren Tucker (dtucker at dtucker.net)
GPG key 11EAA6FA / A86E 3E07 5B19 5880 E860  37F4 9357 ECEF 11EA A6FA (new)
    Good judgement comes with experience. Unfortunately, the experience
usually comes from bad judgement.