Re: libssh-4.0.2 client code problem

[Aris Adamantiadis <aris@xxxxxxxxxxxx>]

Hi Eugene,

That's very strange. I will check out what has happened.

Have you got any information on the distribution/ssh server installed
on the server ? I suspect it's a problem with aes256-ctr.

In order to verify:
samplessh -l oracle -p 1778 -c aes256-cbc alpha-dev30.edf.gxs.com
samplessh -l oracle -p 1778 -c blowfish-cbc alpha-dev30.edf.gxs.com

It would also help if you tried aes128-ctr.

Thanks,

Aris

Eugene Starozhilov a écrit :
> 
> Hi Aris,
> 
> Thanks for fixing server api bug. But I ran into another problem with
> client api.
> These are traces from sshd and  libssh client code:
> 
> ---------------------------  sshd
> --------------------------------------------------
> sshd[22309]: Connection from ::ffff:10.160.123.184 port 44351
> sshd[22309]: debug1: Client protocol version 2.0; client software
> version libssh-0.4.2
> sshd[22309]: debug1: no match: libssh-0.4.2
> sshd[22309]: debug1: Enabling compatibility mode for protocol 2.0
> sshd[22309]: debug1: Local version string SSH-1.99-OpenSSH_3.9p1
> sshd[22341]: debug1: permanently_set_uid: 74/74
> sshd[22341]: debug1: list_hostkey_types: ssh-rsa,ssh-dss
> sshd[22341]: debug1: SSH2_MSG_KEXINIT sent
> sshd[22341]: debug1: SSH2_MSG_KEXINIT received
> sshd[22341]: debug1: kex: client->server aes256-ctr hmac-sha1 none
> sshd[22341]: debug1: kex: server->client aes256-ctr hmac-sha1 none
> sshd[22341]: debug1: expecting SSH2_MSG_KEXDH_INIT
> sshd[22341]: debug1: SSH2_MSG_NEWKEYS sent
> sshd[22341]: debug1: expecting SSH2_MSG_NEWKEYS
> sshd[22341]: debug1: SSH2_MSG_NEWKEYS received
> sshd[22341]: debug1: KEX done
> sshd[22341]: Disconnecting: Corrupted MAC on input.
> ------------------------------------------------------------------------------
> 
> -------------------- libssh client code -----------------------------
> [3] host 10.160.31.50 matches an IP address
> [1] Trying to connect to host: 10.160.31.50:1778 with timeout 1800.0
> [3] Socket connected with timeout
> 
> [1] SSH server banner: SSH-1.99-OpenSSH_3.9p1
> [1] Analyzing banner: SSH-1.99-OpenSSH_3.9p1
> [1] We are talking to an OpenSSH server version: 3.9 (30900)
> [3] Packet size decrypted: 636 (0x27c)
> [3] Read a 636 bytes packet
> [3] 11 bytes padding, 635 bytes left in buffer
> [3] After padding, 624 bytes left in buffer
> [3] Final size 624
> [3] Type 20
> [3] Writing on the wire a packet having 141 bytes before
> [3] 141 bytes after comp + 6 padding bytes = 148 bytes packet
> [3] Writing on the wire a packet having 133 bytes before
> [3] 133 bytes after comp + 6 padding bytes = 140 bytes packet
> [3] Packet size decrypted: 444 (0x1bc)
> [3] Read a 444 bytes packet
> [3] 10 bytes padding, 443 bytes left in buffer
> [3] After padding, 433 bytes left in buffer
> [3] Final size 433
> [3] Type 31
> [3] Writing on the wire a packet having 1 bytes before
> [3] 1 bytes after comp + 10 padding bytes = 12 bytes packet
> [1] SSH_MSG_NEWKEYS sent
> 
> [3] Packet size decrypted: 12 (0xc)
> [3] Read a 12 bytes packet
> [3] 10 bytes padding, 11 bytes left in buffer
> [3] After padding, 1 bytes left in buffer
> [3] Final size 1
> [3] Type 21
> [1] Got SSH_MSG_NEWKEYS
> 
> [3] Set output algorithm to aes256-ctr
> [3] Set input algorithm to aes256-ctr
> 
> [3] Writing on the wire a packet having 17 bytes before
> [3] 17 bytes after comp + 10 padding bytes = 28 bytes packet
> [3] Encrypting packet with seq num: 3, len: 32
> [3] Sent SSH_MSG_SERVICE_REQUEST (service ssh-userauth)
> [3] Decrypting 16 bytes
> [3] Packet size decrypted: 44 (0x2c)
> [3] Read a 44 bytes packet
> [3] Decrypting 32 bytes
> 2010-04-12 13:14:54,211557; 1126189408 procSrvAuth;  Did not receive
> SERVICE_ACCEPT
> --------------------------------------------------------------------------------------------
> 
> sshd receives corrupted MAC and drops connection. It happens when client
> calls ssh_service_request(session, "ssh-userauth");
> 
> I built libssh-4.0.2 from git repository:
> 
> git clone git://git.libssh.org/projects/libssh/libssh.git libssh
> git checkout -b v0-4 origin/v0-4
> 
> with libcrypto library (openssl 0.9.7a).
> 
> 
> The same error can be reproduced using samplessh example with sshd.
> 
> /usr/sbin/sshd -d  -p 1778
> samplessh -l oracle -p 1778 alpha-dev30.edf.gxs.com
> 
> 
> Thank you,
> Eugene
> 
> 
> --- On *Sun, 3/28/10, Aris Adamantiadis /<aris@xxxxxxxxxxxx>/* wrote:
> 
> 
>     From: Aris Adamantiadis <aris@xxxxxxxxxxxx>
>     Subject: Re: libssh-0.4.2 server api bug
>     To: libssh@xxxxxxxxxx
>     Date: Sunday, March 28, 2010, 3:51 PM
> 
>     Hi,
> 
>     This was resolved in d2bb97c1c6f32c167e1a6093201e01a52bfe0e0d. Thanks
>     for your feedback on this bug.
> 
>     Regards,
> 
>     Aris
> 
>     Aris Adamantiadis a écrit :
>     > Hi
>     > Oops, we missed that bug for the release. I will find a solution.
>     >
>     > Aris
>     >
>     > Eugene Starozhilov a écrit :
>     >> Hi Aris,
>     >>
>     >> The new release libssh-0.4.2 has the same problem as libssh-0.4.1
>     >> (described below). samplesshd doesn't work with standard LINUX ssh
>     >> client. Is any chance to get it fixed soon?
>     >>
>     >>
>     >> Thank you,
>     >> Eugene
>     >>
> 
>