News Group Posts

sshd stty login

From: Bela Lubkin <belal@sco.com>
Subject: Re: sco-list: [OFF] OpenSSH on OpenServer 5.0.6a
Date: Wed, 1 May 2002 08:29:42 GMT
References: <20020430191159.I10046@mammoth.ca.sco.com>
<20020501023509.GD26641@jpradley.jpr.com> 

Jean-Pierre Radley wrote:

> On jpradley.jpr.com, /usr/local/etc/sshd_config contains:
> 
>    UseLogin no
> 
> Bela, what do you see for stty -a (and for that matter, for id -l) after
> running ssh jpradley.jpr.com?

stty settings look sane; but I'm coming from a Unix ssh client that will
have pushed sane settings.  `id -l` says I'm root, and one consequence
is the message:

  prwarn: Cannot update .prwarn_time in root's home directory
  Permission denied

during login.  The SecureWare security commands think I'm root -- I
doubt this is a good thing.

> If in fact I change UseLogin to be 'yes', I can't even get in:
> 
>    LOGIN: ERROR: Illegal option -- h
>    Usage: LOGIN [ -c ] [ [ -f ] username [ name=value ]... ]
>       or: LOGIN [ -c ] -r remhost remuser username [ name=value ]...
>    Connection to jpradley.jpr.com closed.
> 
> [OpenSSH_3.1p1]

This used to work in some older release of OpenSSH.  Might still work, I
haven't looked at the code -- see if it has an #ifdef or other control
over whether it includes that "-h" option.  It is trying to pass "-h
remote.host.dom" to login, which is then supposed to store that in utmp.
The nearest equivalent in OSR5's login is the "-r" flag, and it has an
important difference.  You pass it "-r remote.host.dom remuser".  It
then looks up whether that user is allowed to login with no password --
that is, it checks ~user/.rhosts and /etc/hosts.equiv.

I believe you _could_ use the -r flag, as long as you passed in an
"impossible" remote username, e.g. "-r remote.host.dom //sshd//".  That
wouldn't match the local user's name, so hosts.equiv wouldn't come into
play; and "//sshd//" wouldn't appear in the local user's .rhosts.  Or at
least if it did, it would be because the local user was _trying_ to
shoot himself in the foot.

So recompile sshd to either leave out the "-h remhost" part, or change
it to "-r remhost //sshd//"; see how it goes.

>Bela<
 

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