Re: libssh and python twisted conch ssh

[Aris Adamantiadis <aris@xxxxxxxxxxxx>]

Hi,

I took a look at your pcap (next time please just attach it :)).
It seems like twisted sends the key exchange packet right away before
listening for the client's banner.
As the packet is already buffered, the packet parsing is never triggered
because it's waiting for socket input first.

I'll try to find a solution asap.

Aris

Le 21/01/13 15:11, Johannes Krude a écrit :
> hi,
> 
> I am trying to interface a libssh client with a python twisted conch
> server. Unfortunately the key exchange does no succeed. It seems libssh
> rejects the key exchange initiation. Below are detailed logs and dumps.
> Does twisted send malformed data, does libssh not recognize compliant
> data, or is this some other kind of problem?
> 
> Greetings, johannes
> 
> 
> ./samplessh from both 0.5.2 and rev de096910b37ca3474fc37d421fb051a234f5cce0
> shows:
> Connection failed : Timeout connecting to xx.xx.xx.xx
> 
> An anonymized pcap from rev de09...
> (use with `cat | base64 -d | gzip -d > file.pcap`):
> H4sIAFVL/VAAA82UXUhTYRjHn7NNPdsqdNkmEWEpYbCztvlBC1vLCsoLCRS8KtjHWZturjzG+rhZ
> QVIXkVJXFjipqItRYWkXGQUiJBHsohsxdlXGRkJBF0Hoep53nTM9rl134OU853nH7/m///M/+zg7
> OaEBHchXPg/A4f3CkZWTo4d56MSaFpjdS3fffM/86L4+xsMxgPZsjQc8lVdSBo4zPH5rseSmwDz7
> 69s7+nFS4+LTVgCNruKFTsMb4FnFAvU5rbaKyHdGiuQCs8BHshbaATzQXBl/RVSigzk3tbRwUIP0
> +aTJnFx5xMgpIm+6P7qT6EjWETmH5A6kdpTS3JI1Mc3PVZrnka5NVIOUbkSNHNO7TGQiVizy8Bst
> oaXWyi2n6knrfFalVUvURB3Xt+dUgYi0BqJ2dx8XnDa70BMPS0NiYLMBtx/oaof1B/be6ppoOndz
> rrPrdj6K4rcHwsFgWBRCYiQS9Q4IZwZj5886BCnkdeBulSSFhEHJi+U1ryg5W9sE/9CgVS59fiod
> LqfcZeXfrnO/0qUSu36vNCS3lRr7vkgsHgzjJNooPuBOc0CUWLdQ+Pz/kxBTKOr1M6esrIoGWv/Z
> 1Q/EBkTrpUjYp34oXobcsJuicHqxbLi2snBNbgyXewbDdbkYrkqgOBCx6hMPvQjrLUU8ka1lxHsl
> iXVIdClEjohyuFA/xcNua7PZDTTmRqNeEb7he2tJ7aIMv59Yn2H3DI7KJKq5vkPjSoabaNRVJL7s
> 54FM8pUS3pPdxoSPqIRnFOFHZeHWn4wKsMNIfztGinbHRbEe15oXQBO/9pc138wmPlVNXGUTa9aa
> X5hIxH3TfDlXdjNXkiVcWSVXtqRlV8Y+E5WI4lxZYgMjjpcg5hM1SPygEL/IxIdzZU9tYad+ojp1
> Hqmv10dOMBL1D+KMhEfuBQAA
> 
> My own libssh client using 0.5.2 with high LOG_VERBOSITY says:
> [1] libssh 0.5.2 (c) 2003-2010 Aris Adamantiadis (aris@xxxxxxxxxxxx)
> Distributed under the LGPL, please refer to COPYING file for information
> about your rights, using threading threads_noop
> [3] host xx.xx.xx.xx matches an IP address
> [2] Nonblocking connection socket: 3
> [2] Socket connecting, now waiting for the callbacks to work
> [3] ssh_connect: Actual timeout : 30000
> [3] Received POLLOUT in connecting state
> [1] Socket connection callback: 1 (0)
> [3] Received banner: SSH-2.0-Twisted
> [1] SSH server banner: SSH-2.0-Twisted
> [1] Analyzing banner: SSH-2.0-Twisted
> [3] Enabling POLLOUT for socket
> [1] Error : Timeout connecting to xx.xx.xx.xx
> [3] ssh_connect: Actual state : 9
> ssh_connect: Timeout connecting to xx.xx.xx.xx
> [3] Writing on the wire a packet having 16 bytes before
> [3] 16 bytes after comp + 11 padding bytes = 28 bytes packet
> [3] Enabling POLLOUT for socket
> 
>