Re: SSH channel forwarding fails on ieof

[Aris Adamantiadis <aris@xxxxxxxxxxxx>]

Hi,

I will need some source code samples to debug this. Quick questions:
-Are you using nonblocking sessions ?
-Are you sure the ssh_channel_open_session returns SSH_OK every time ?
-Do you check all error codes from libssh ?
-Please increase the verbosity level as we cannot see all that is done here.

Thanks,

Aris

Le 25/09/13 13:37, Pugnator a écrit :
> It's a pity but it seems I was in hurry. The issue is still reproducing
> on some machines.
> The error code is the same
> 
> channel_by_id: 0: bad id: channel free
> 
> But issue is not stable - reproduces on specific machines only
> 
> 
> On 09/25/2013 04:27 AM, Pugnator wrote:
>> Thanks a lot for your reply.
>> Yes, it is the case for me as I'm creating multiple channels
>> simultaneously.
>> I used stable repo from Debian 7. I followed your suggestion and
>> compiled 0.6rc.
>> The issue was not reproduced after it.
>>
>>
>> On 09/25/2013 12:36 AM, Aris Adamantiadis wrote:
>>> Hi,
>>>
>>> Could you try again with libssh 0.5.5 or 0.6rc and tell me if you can
>>> reproduce the problem ? This behaviour recalls me of a bug that has been
>>> fixed in 0.5.3, and would happen when you open multiple channels. Is it
>>> the case ?
>>>
>>> Thanks,
>>>
>>> Aris
>>>
>>> Le 24/09/13 18:21, Pugnator a écrit :
>>>> I use libssh 0.5.2 binding for C under Linux. In my program I create
>>>> SSH
>>>> tunnel to XenServer. It worked perfectly until I updated to the most
>>>> recent XenServer 6.2. After it ssh tunneling started failing with
>>>>
>>>> [1] Analyzing banner: SSH-2.0-OpenSSH_4.3
>>>> [1] We are talking to an OpenSSH client version: 4.3 (40300)
>>>> [1] placing 18 bytes into channel buffer (stderr=0)
>>>> [1] Error : Channel opening failure: channel 44 error (2) Connection
>>>> refused
>>>>
>>>> On server side there is records in /var/log/secure:
>>>>
>>>> Sep 24 20:12:10 proxima sshd[20782]: pam_unix(sshd:session): session
>>>> opened for user root by (uid=0)
>>>> Sep 24 20:12:10 proxima sshd[20792]: Accepted password for root from
>>>> 10.250.144.221 port 55673 ssh2
>>>> Sep 24 20:12:10 proxima sshd[20792]: pam_unix(sshd:session): session
>>>> opened for user root by (uid=0)
>>>> Sep 24 20:12:11 proxima sshd[16132]: channel_by_id: 0: bad id:
>>>> channel free
>>>> Sep 24 20:12:11 proxima sshd[16132]: Disconnecting: Received ieof for
>>>> nonexistent channel 0.
>>>> Sep 24 20:12:11 proxima sshd[16132]: pam_unix(sshd:session): session
>>>> closed for user root
>>>>
>>>>
>>>> The most strange is the ssh server version is the same on old and new
>>>> servers:
>>>> OpenSSH_4.3p2, OpenSSL 0.9.8e-fips-rhel5 01 Jul 2008
>>>>
>>>> I'm not sure how to debug such an issue. Sometimes tunnel establishes
>>>> and works but it is 1 out of 100 tries.
>>>>
>>>
>>
>>
> 
>