Hello,
Any comment here?
Ciao,
Gerhard
On 17.12.2024 19:19, Gerhard Wiesinger wrote:
> Hello,
>
> I'm having a crash problem with latest version (also previous ones)
> with ssh private key authentication and Putty Pageant. Looks like
> there is a buffer overflow involved. With several smaller keys (e.g.
> ssh-ed25519) it works well.
>
> I found a scenario to reproduce it:
> 1. Generate a RSA 4096 Bit length private/public key pair
> 2. Load it on the Windows client into Putty Pageant
> 3. Put public key at the server at ~/.ssh/authorized_keys
> 4. open connection to the server => crash, see logs
>
> Looks like it is a bug in the old libssh library version with large
> private/public keys.
>
> Can you please fix the topic.
>
> Some questions:
> - Is the used libssh version really version 0.9.2?
> - The logs have some entries with: agent_talk - len of request
> - That has been changed in git to another logging in 2011:
> https://git.libssh.org/projects/libssh.git/commit/?id=ba4f10dc4657952ec47f71dfae90d9fba2eb6759
> - Version 0.9.2 has been released in 2019:
> https://www.libssh.org/2019/11/07/libssh-0-9-2/
> - So it looks, not the version 0.9.2 is used
> - Any plans to upgrade to latest version of libssh 0.11.0 while
> keeping Putty Pageant Agent support?
> - Upgrade plans to newer Putty version?
> - Is there a newer nightly Windows build from newer git sources
> available?
>
> Version:
> - X2Go Client 4.1.2.3-ba65703-kdrclient-a3134d6
> - according to the logs: ssh_connect: libssh 0.9.2 (c) 2003-2019
> Aris Adamantiadis, Andreas Schneider and libssh contributors.
> Distributed under the LGPL, please refer to COPYING file for
> information about your rights, using threading threads_pthread
> - Server: (not relevant but version is: x2goserver-4.1.0.6-4.fc41.x86_64)
>
> Thnx.
>
> Ciao,
> Gerhard
>
> Relevant debug log file on the client:
> x2go-DEBUG-src\sshmasterconnection.cpp:674> Setting SSH directory to
> C:/Users/user/ssh
> [2024/12/17 08:03:09.904803, 3] : agent_talk - len of request: 1
> [2024/12/17 08:03:09.904803, 3] : agent_talk - response length: 568
> [2024/12/17 08:03:09.904803, 1] ssh_agent_get_ident_count: Answer
> type: 12, expected answer: 12
> [2024/12/17 08:03:09.904803, 3] ssh_agent_get_ident_count: Agent
> count: 1
> [2024/12/17 08:03:09.904803, 3] ssh_userauth_agent: Trying identity
> rsa-key-20241217
> [2024/12/17 08:03:09.904803, 3] ssh_key_algorithm_allowed: Checking
> rsa-sha2-512 with list
> <ssh-ed25519-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp256-cert-v01@openssh.com,rsa-sha2-512-cert-v01@openssh.com,rsa-sha2-256-cert-v01@openssh.com,ssh-rsa-cert-v01@openssh.com,ssh-dss-cert-v01@openssh.com,ssh-ed25519,ecdsa-sha2-nistp521,ecdsa-sha2-nistp384,ecdsa-sha2-nistp256,rsa-sha2-512,rsa-sha2-256,ssh-rsa,ssh-dss>
> [2024/12/17 08:03:09.904803, 3] ssh_key_algorithm_allowed: Checking
> rsa-sha2-512 with list
> <ssh-ed25519-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp256-cert-v01@openssh.com,rsa-sha2-512-cert-v01@openssh.com,rsa-sha2-256-cert-v01@openssh.com,ssh-rsa-cert-v01@openssh.com,ssh-dss-cert-v01@openssh.com,ssh-ed25519,ecdsa-sha2-nistp521,ecdsa-sha2-nistp384,ecdsa-sha2-nistp256,rsa-sha2-512,rsa-sha2-256,ssh-rsa,ssh-dss>
> [2024/12/17 08:03:09.904803, 3] packet_send2: packet: wrote [type=5,
> len=32, padding_size=14, comp=17, payload=17]
> [2024/12/17 08:03:09.904803, 3] ssh_service_request: Sent
> SSH_MSG_SERVICE_REQUEST (service ssh-userauth)
> [2024/12/17 08:03:09.904803, 3] ssh_socket_unbuffered_write: Enabling
> POLLOUT for socket
> [2024/12/17 08:03:09.949398, 3] ssh_packet_socket_callback: packet:
> read type 6 [len=32,padding=14,comp=17,payload=17]
> [2024/12/17 08:03:09.949398, 3] ssh_packet_process: Dispatching
> handler for packet type 6
> [2024/12/17 08:03:09.949398, 3] ssh_packet_service_accept: Received
> SSH_MSG_SERVICE_ACCEPT
> [2024/12/17 08:03:09.949398, 3] ssh_socket_unbuffered_write: Enabling
> POLLOUT for socket
> [2024/12/17 08:03:09.949398, 3] packet_send2: packet: wrote [type=50,
> len=608, padding_size=11, comp=596, payload=596]
> [2024/12/17 08:03:09.959352, 3] ssh_packet_socket_callback: packet:
> read type 60 [len=576,padding=19,comp=556,payload=556]
> [2024/12/17 08:03:09.959352, 3] ssh_packet_process: Dispatching
> handler for packet type 60
> [2024/12/17 08:03:09.959352, 3] ssh_userauth_agent: Public key of
> rsa-key-20241217 accepted by server
> [2024/12/17 08:03:09.959352, 3] ssh_key_algorithm_allowed: Checking
> rsa-sha2-512 with list
> <ssh-ed25519-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp256-cert-v01@openssh.com,rsa-sha2-512-cert-v01@openssh.com,rsa-sha2-256-cert-v01@openssh.com,ssh-rsa-cert-v01@openssh.com,ssh-dss-cert-v01@openssh.com,ssh-ed25519,ecdsa-sha2-nistp521,ecdsa-sha2-nistp384,ecdsa-sha2-nistp256,rsa-sha2-512,rsa-sha2-256,ssh-rsa,ssh-dss>
> [2024/12/17 08:03:09.959352, 3] ssh_key_algorithm_allowed: Checking
> rsa-sha2-512 with list
> <ssh-ed25519-cert-v01@openssh.com,ecdsa-sha2-nistp521-cert-v01@openssh.com,ecdsa-sha2-nistp384-cert-v01@openssh.com,ecdsa-sha2-nistp256-cert-v01@openssh.com,rsa-sha2-512-cert-v01@openssh.com,rsa-sha2-256-cert-v01@openssh.com,ssh-rsa-cert-v01@openssh.com,ssh-dss-cert-v01@openssh.com,ssh-ed25519,ecdsa-sha2-nistp521,ecdsa-sha2-nistp384,ecdsa-sha2-nistp256,rsa-sha2-512,rsa-sha2-256,ssh-rsa,ssh-dss>
> [2024/12/17 08:03:09.959352, 3] : agent_talk - len of request: 1180
> QObject::~QObject: Timers cannot be stopped from another thread
> <---------- CRASH HERE ---------->
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