ssh -rs crashed on Zero lenght version information

[Paulo-21]

Hello,
I encountered an error when running ssh -rs in several threads.
I'm trying to connect to a real ssh server, which may be behind a firewall or a specific security system.

[HsuJv]

Hi

Could you help use python or any other script to create a TCP connection to your ssh server ip:port, and call read on this connection once connected?

Looks like the server doesn't respond their ssh version to us, the protocol version exchange (https://www.rfc-editor.org/rfc/rfc4253#section-4.2) fails and panic with some careless code

BRs.

[Paulo-21]

I can add that there is "portsentry -atcp" activated on the server and the openssh version is 7.6p1.
It would be difficult to do that because i have a limited access to it.
Can it be possible to return an error like "Inapropriate_ssh_response_from_server" rather than panic ?

[HsuJv]

Yes, you're right, it shall throw errors instead of panic.

Since you mentioned portsentry is running. I guess it might require us to send out the version negotiation first.
I'll also make some changes to see if this can fix the issue.

Could you please use ssh-rs = { git = "https://github.com/HsuJv/ssh-rs.git", branch = "patch_85" } to help verify this issue?

BRs

[Paulo-21]

Hey,
I have tested and it work properly.
Thank you for your responsiveness and your kindness as always ;)