Re: su doesn't work "Authentication failure"

["Damon L. Chesser" <damon@damtek.com>]

paul wrote:
> Hello,
>
> on my debian etch machine 'su' doesn't work if a password is needed.
> It is possible to do 'su someuser' from root but it's not possible to
> get back to root then using just 'su' or change from a normal user to
> another user account.
>
>
> myserver:/tmp$ su
> Password:
> su: Authentication failure
> Sorry.
>
> auth.log says:
> Jan 31 15:44:18 myserver su[27729]: (pam_unix) authentication failure;
> logname= uid=1000 euid=1000 tty=pts/4 ruser=myuser rhost=  user=root
> Jan 31 15:44:20 myserver su[27729]: pam_authenticate: Authentication
> failure
> Jan 31 15:44:20 myserver su[27729]: FAILED su for root by myuser
> Jan 31 15:44:20 myserver su[27729]: - pts/4 myuser:root
>
> I suspect sth. in with the pam module got broken.
>
> Any suggestions how to go on?
>
> thx, paul
>
>
>   
Paul,

I had the same issue.  I fixed it by doing two things: 

1.  I used sudo to su to root "sudo su"
2.  As I had a BadCRC reported on a HD, I had to re-configure my 
hardware setup and re-install.

The first is a bandaide.  The 2nd is a shotgun to kill a bug.  Both 
worked.  The source was never found.

HTH

--
Damon L. Chesser
damon@damtek.com