cygwin64 OpenSSH_8.1p1 client segmentation fault

[vadim]

Thanks.
Do you think the fact that 32bit version is working fine (more or less) 
and the previous ssh 64 bit version (I suspect this was the version 
before Sep 2019, but I can't say for sure as Cygwin does not leave any 
traces of the previous version I used before the upgrade) was working 
without any issues still suggests BLODA?
I think logically this is caused by new ssh version (which probably 
interfere with some of the other libs) rather than my specific setup. I 
mean - setup may cause the issue, but the previous version was working 
fine with this setup, so this looks like a regression (i.e. new version 
is more demanding or more restrictive in terms of surrounding environment).

Is there a way I can rollback to ssh version before 8.0p1-2 (the oldest 
I see now in cygwin64) to prove the point (or at least continue using 
the working for me version)?


/From/: Eliot Moss <moss at cs dot umass dot edu>

My cygwins (32 and 64 bit) report exactly the same for uname -a and ssh -V,
yet all works fine for me.

This suggests BLODA or some different networking setup of some kind.  Not sure
this positive report narrows down much, but it's a data point for you ...

Eliot Moss


On 14/12/2019 16:12, vadim wrote:
> I have just installed the latest cygwin32 and cygwin64 from scratch 
> into new folders.
>
> Tried ssh client in both.
>
> The result is:
>
> - cygwin32 CYGWIN_NT-6.1-WOW 3.0.7(0.338/5/3) 2019-04-30 18:04 i686
> ssh works, but it hangs after I disconnect myself. I have to kill ssh 
> process to continue the cygwin session.
>
> - cygwin64 CYGWIN_NT-6.1-WOW 3.0.7(0.338/5/3) 2019-04-30 18:04 x86_64
> ssh dies immediately after the connection is established using 
> ssh-keys (i.e. after a successful login)
>
> Both has version:
> OpenSSH_8.1p1, OpenSSL 1.1.1d  10 Sep 2019
>
> Vadim
>
>
> On 14/12/2019 14:08, vadim wrote:
>> Hi,
>>
>> I have recently upgraded Cygwin packages. After the upgrade ssh 
>> client stopped working.
>> It connects and logins using ssh keys as normal, but then the 
>> connection is immediately dropped (ssh client process dies and 
>> segfaults under strace).
>> This is definitely not the server side issue as I have an old 
>> cygwin32 version (on the same PC) where ssh client logins to the same 
>> server with the same ssh-keys just fine.
>> I am also able to connect using putty with same ssh-keys.
>>
>> I was trying to rollback my installation of Cygwin, but unfortunately 
>> setup-x86_64.exe does not offer this possibility.
>> Please help me rolling back to some version of Cygwin where ssh 
>> client is working.
>> I tried all 3 versions of ssh and ssl that are available. Tried 
>> re-installing OpenSSH and OpenSSL packages, but nothing helps.
>>
>> This 64-bit latest version is not working:
>> $ ssh -V
>> OpenSSH_8.1p1, OpenSSL 1.1.1d  10 Sep 2019
>>
>> This is working 32bit version:
>> $ ssh -V
>> OpenSSH_6.1p1, OpenSSL 1.0.1e 11 Feb 2013
>>
>> ssh session logs attached:
>>
>> ssh-session-1.log - connection to host in known_hosts - without 
>> questions, login is ok, then immediate disconnect.
>>
>> ssh-session-1.vvv.log - same but ssh -vvv option used
>>
>> ssh-session-1-strace.log - same under strace
>>
>> ssh-V.strace.log - running ssh -V and strace ssh -V (which also crashes)
>>
>> see also cygcheck.out
>>
>> thanks in advance for any help,
>> Vadim Goryunov
>>
>


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