export public key to environment

[Jakub Jelen]

On Wed, 2018-11-14 at 11:59 +1030, David Newall wrote:
> Hello all,
> 
> Some while ago I developed a small patch for sshd, for internal 
> consumption, so that, when a client uses a private key, the 
> corresponding public key is exported in the environment.  I use it
> to 
> identify which of a multitude of devices is logged in to a shared 
> account, but I'm sure there are many uses to which it could be put.  
> Now, I wonder whether there already was a way of achieving the same 
> result.  I need to be able to identify previously unseen devices, so
> I 
> cannot just store the public key (c.f. authorized_keys) before use.
> 
> If this patch does indeed provide a new function (could not
> otherwise 
> achieve the desired outcome), is it something which would be
> welcomed 
> for inclusion in the official source?  I've attached the patch so
> that 
> you can see what's involved.

Hello,
If I am right, something like this was solved few releases back
(OpenSSH 7.6) based on the bug #2408 [1], which handles this in more
general manner (expose information about all authentication methods
that succeeded).

Brief description can be found in manual page of sshd_config under the
ExposeAuthInfo option. The most of the source code can be found here
[2]

[1] https://bugzilla.mindrot.org/show_bug.cgi?id=2408
[2] https://anongit.mindrot.org/openssh.git/commit/?id=8f574959

Regards,
-- 
Jakub Jelen
Software Engineer
Security Technologies
Red Hat, Inc.