#638940 openssh-client: Regression from 5.5p1 to 5.8p1 - unable to connect to servers

Package:
openssh-client
Source:
openssh
Description:
secure shell (SSH) client, for secure access to remote machines
Submitter:
eyck
Date:
2011-08-23 07:42:06 UTC
Severity:
important
#638940#5
Date:
2011-08-23 07:23:30 UTC
From:
To:
Connections fail with:
Read from socket failed: Connection reset by peer

example failed connections:
debug1: Remote protocol version 2.0, remote software version OpenSSH_4.5p1 FreeBSD-20061110
debug1: match: OpenSSH_4.5p1 FreeBSD-20061110 pat OpenSSH_4*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.8p1 Debian-7
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-ctr hmac-md5 zlib@openssh.com
debug1: kex: client->server aes128-ctr hmac-md5 zlib@openssh.com
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
Read from socket failed: Connection reset by peer

and:
debug1: Remote protocol version 2.0, remote software version dropbear_0.52
debug1: no match: dropbear_0.52
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.8p1 Debian-7
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-ctr hmac-md5 zlib@openssh.com
debug1: kex: client->server aes128-ctr hmac-md5 zlib@openssh.com
debug1: sending SSH2_MSG_KEXDH_INIT
debug1: expecting SSH2_MSG_KEXDH_REPLY
Read from socket failed: Connection reset by peer

also:
debug1: Remote protocol version 2.0, remote software version OpenSSH_5.1p1 Debian-5
debug1: match: OpenSSH_5.1p1 Debian-5 pat OpenSSH*
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_5.8p1 Debian-7
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-ctr hmac-md5 zlib@openssh.com
debug1: kex: client->server aes128-ctr hmac-md5 zlib@openssh.com
debug1: SSH2_MSG_KEX_DH_GEX_REQUEST(1024<1024<8192) sent
debug1: expecting SSH2_MSG_KEX_DH_GEX_GROUP
Read from socket failed: Connection reset by peer


downgrading to 5.5p1 solves the problem (also using dbclient from dropbear works)

Some servers work ok even with 5.8 client, particularly 5.8 openssh servers