Re: key exchange fails in ssh_connect using libssh 0.10.4

[Jijo Thomas <jijo7thomas@xxxxxxxxx>]

Thank you Norbert Pócs.
I could add the missing default algorithms in kex.c and proceed.

Regards,
Jijo

On Mon, Jan 9, 2023 at 8:27 PM Norbert Pocs <npocs@xxxxxxxxxx> wrote:

> Hi Thomas,
>
> I see the server -
>
>  no match for method kex algos: server [diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1]
>
> has only sha1 kex methods enabled, which are disabled by default in
> version 0.10 of libssh. Try to enable
> the needed kex methods in the configuration file or try to avoid using
> sha1 if possible.
>
> Hope this helps!
>
> Regards
> Norbert Pócs
>
>
> On Mon, Jan 9, 2023 at 3:03 PM Jijo Thomas <jijo7thomas@xxxxxxxxx> wrote:
>
>> Hey folks,
>>
>> I'm trying to use a ssh_connect using a recently compiled libssh 0.10.4
>> (using openssl 1.1.1k)
>> But we ran into a key exchange error. Following is the log.
>>
>> [2023/01/09 16:37:44.874356, 2] ssh_connect:  libssh 0.10.4 (c) 2003-2022 Aris Adamantiadis, Andreas Schneider and libssh contributors. Distributed under the LGPL, please refer to COPYING file for information about your rights, using threading threads_winlock
>> [2023/01/09 16:37:44.881334, 3] getai:  host x.x.x.x matches an IP address
>> [2023/01/09 16:37:44.885324, 2] ssh_socket_connect:  Nonblocking connection socket: 512
>> [2023/01/09 16:37:44.887321, 2] ssh_connect:  Socket connecting, now waiting for the callbacks to work
>> [2023/01/09 16:37:44.887903, 3] ssh_connect:  Actual timeout : 10000
>> [2023/01/09 16:37:45.139544, 3] ssh_socket_pollcallback:  Received POLLOUT in connecting state
>> [2023/01/09 16:37:45.140542, 1] socket_callback_connected:  Socket connection callback: 1 (0)
>> [2023/01/09 16:37:45.140542, 3] ssh_socket_unbuffered_write:  Enabling POLLOUT for socket
>> [2023/01/09 16:37:45.376008, 3] callback_receive_banner:  Received banner: SSH-2.0-Cisco-1.25
>> [2023/01/09 16:37:45.377005, 2] ssh_client_connection_callback:  SSH server banner: SSH-2.0-Cisco-1.25
>> [2023/01/09 16:37:45.377005, 2] ssh_analyze_banner:  Analyzing banner: SSH-2.0-Cisco-1.25
>> [2023/01/09 16:37:45.390968, 3] ssh_client_select_hostkeys:  Order of wanted host keys: "ssh-ed25519,ecdsa-sha2-nistp521,ecdsa-sha2-nistp384,ecdsa-sha2-nistp256,rsa-sha2-512,rsa-sha2-256"
>> [2023/01/09 16:37:45.391964, 1] ssh_known_hosts_read_entries:  Failed to open the known_hosts file 'C:\Users\xxxxx/.ssh/known_hosts': No such file or directory
>> [2023/01/09 16:37:45.391964, 1] ssh_known_hosts_read_entries:  Failed to open the known_hosts file '/etc/ssh/ssh_known_hosts': No such file or directory
>> [2023/01/09 16:37:45.391964, 3] ssh_client_select_hostkeys:  No key found in known_hosts; changing host key method to "ssh-ed25519,ecdsa-sha2-nistp521,ecdsa-sha2-nistp384,ecdsa-sha2-nistp256,rsa-sha2-512,rsa-sha2-256"
>> [2023/01/09 16:37:45.391964, 3] ssh_socket_unbuffered_write:  Enabling POLLOUT for socket
>> [2023/01/09 16:37:45.391964, 3] packet_send2:  packet: wrote [type=20, len=852, padding_size=7, comp=844, payload=844]
>> [2023/01/09 16:37:45.392965, 3] ssh_send_kex:  SSH_MSG_KEXINIT sent
>> [2023/01/09 16:37:45.626340, 3] ssh_packet_socket_callback:  packet: read type 20 [len=308,padding=4,comp=303,payload=303]
>> [2023/01/09 16:37:45.627339, 3] ssh_packet_process:  Dispatching handler for packet type 20
>> [2023/01/09 16:37:45.627339, 1] ssh_kex_select_methods:  kex error : no match for method kex algos: server [diffie-hellman-group-exchange-sha1,diffie-hellman-group14-sha1], client [curve25519-sha256,curve25519-sha256@xxxxxxxxxx,ecdh-sha2-nistp256,ecdh-sha2-nistp384,ecdh-sha2-nistp521,diffie-hellman-group18-sha512,diffie-hellman-group16-sha512,diffie-hellman-group-exchange-sha256,diffie-hellman-group14-sha256]
>> [2023/01/09 16:37:45.627339, 3] ssh_connect:  current state : 9
>>
>>
>> It is still working fine using libssh 0.9.4 dll
>>
>> It could be something I missed while compiling the new library. I had created the solution using cmake, and compiled the ssh.dll using Visual Studio 2017.
>> Any leads to solve the problem is appreciated.
>>
>>
>> Regards,
>>
>> Jijo
>>
>>