Bug#478263: xdm: does not allow to log in when no password is set

[Michal Suchanek <michal.suchanek@ruk.cuni.cz>]

On Oct 21, 2008, at 8:41 AM, Trent W. Buck wrote:

> On Tue, Oct 21, 2008 at 04:38:35PM +1100, Trent W. Buck wrote:
> > > When I try to log in as a user with no password set xdm asks for a
> > > password and fails to verify it.
> >
> > I can reproduce this problem.
>
> I can log in with no problem using login(8) on the tty, so I tried
>
>     cp --backup /etc/pam.d/{login,xdm}
>     /etc/init.d/xdm
>
> This didn't help.  Nor does anything useful turn up in /var/log, even
> with "debug" on all pam_unix.so entries in /etc/pam.d/common-*.
>
>     Oct 21 17:08:49 Clio xdm[12858]: pam_unix(xdm:auth):  
> authentication failure; logname= uid=0 euid=0 tty=:0 ruser= rhost=   
> user=twb
>     Oct 21 17:08:51 Clio xdm[12858]: LOGIN FAILURE ON :0, (null)
>     Tue Oct 21 17:08:51 2008 xdm error (pid 12858):  
> pam_authenticate failure: Authentication failure

This is because the moment xdm asks for a password it already failed  
to log you in. It should verify that you actually do have a password  
before asking for one.

Thanks

MS