Auth_Banner question

[Damien Miller]

On Fri, 19 Apr 2013, Jonathan Pauli wrote:

> I'm working with a pure PHP implementation of the SSH2 protocol.

I'm terrified.

> So, I'm wondering if there is some way to trigger sshd to send the banner.
> Can I request it explicitly with some message to sshd?

sshd sends the banner for protocol 2 connections at before it responds to
the the first SSH_MSG_USERAUTH_REQUEST packet. I.e

Client: SSH_MSG_USERAUTH_REQUEST
Server: SSH_MSG_USERAUTH_BANNER
Server: SSH2_MSG_USERAUTH_SUCCESS, SSH2_MSG_USERAUTH_FAILURE
        (or a userauth method-specific reply)

Have a look at auth2.c:input_userauth_request() to see how it works.

There isn't anything else you can do to trigger it than attempting
authentication.

-d