[SSSD] [PATCH] PAM: Remove authtok from PAM stack with OTP

Jakub Hrozek jhrozek at redhat.com
Wed Oct 22 15:03:15 UTC 2014


On Wed, Oct 22, 2014 at 10:58:07AM -0400, Nathaniel McCallum wrote:
> On Tue, 2014-10-21 at 20:34 +0200, Lukas Slebodnik wrote:
> > On (21/10/14 20:06), Jakub Hrozek wrote:
> > >On Tue, Oct 21, 2014 at 01:29:53PM -0400, Nathaniel McCallum wrote:
> > >> On Tue, 2014-10-21 at 00:44 +0200, Lukas Slebodnik wrote:
> > >> > ehlo,
> > >> > 
> > >> > We remove the password from the PAM stack when OTP is used to make sure
> > >> > that other pam modules (pam-gnome-keyring, pam_mount) cannot use it anymore
> > >> > and have to request a password on their own.
> > >> > 
> > >> > Resolves: https://fedorahosted.org/sssd/ticket/2287
> > >> > 
> > >> > Simple patch is attached.
> > >> 
> > >> I may be wrong, but I think that making the pam_add_response() and
> > >> pam_set_item() errors non-fatal is incorrect. Attempting to use the OTP
> > >> credentials again could result in further errors, keyring problems or
> > >> account locking. It seems to me that it would better to fail the
> > >> authentication if you cannot guarantee that OTP credentials will not be
> > >> reused.
> > >
> > >On the other hand, logging in as the user in question (and then letting
> > >him to sudo) might be the only way of getting access into the system at
> > >all..
> > Should I change it or no?
> > 
> > It would be very simple change :-)
> 
> I'm not sure I understand Jakub's objection. Could someone clarify?

I was just suggesting to attempt to proceed with login if possible...

> 
> As I understand it, a failure in these functions is largely restricted
> to thinks like OOM. In such a case, I wonder if login will be possible
> at all.

..but after some more thinking I agree with you. If those two functions
fail, we are looking at a genuine bug, so it's better to abort.



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