[buildd-tools-devel] Bug#736642: Bug#736642: schroot: PAM error: No module specific data is present

[Roger Leigh]

On Sat, Jan 25, 2014 at 08:09:03PM +0100, Thomas Bechtold wrote:
> I created a clean chroot with debootstrap for sid amd64. I try to use
> this chroot env together with schroot to run autopkgtests.
> When I login to the chroot and then logout, I get the following error:
> 
> E: PAM error: No module specific data is present
> 
> Attached is the complete log with debugging information.
> I already tried to build schroot by myself and just ignored the thrown
> error from lib/sbuild/auth/pam.cc when pam_close_session() fails. If I
> ignore the error, everything works as expected but I guess that's not
> the correct resolution for the problem.

No; we can't afford to ignore the error.  Depending upon what happens
after this point, it might well be a security issue or cause dataloss
depending upon what PAM has been configured to do, though this is
probably unlikely.  But it would certainly be against the spirit of the
PAM API to ignore it.

I think it's most likely that the PAM error is external to schroot;
schroot just asks PAM to start, stop, authenticate etc. and does not
really have any input into what it does.  I would suspect this error
is the fault of a single PAM module.  If it would be possible to
identify which is at fault, we can look into it in more detail.

You could try commenting out the various lines of /etc/pam.d.schroot
and also in the referenced generic files if they don't help.  PAM
might have some means of enabling debugging messages here, but I
don't know for sure.


Regards,
Roger

-- 
  .''`.  Roger Leigh
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