pam_radius fails after the latest libradius security patch...

From: Peter Eriksson <pen_at_lysator.liu.se>
Date: Fri, 28 May 2021 12:26:02 UTC
After upgrading FreeBSD 12.2 in order to get the fix from 'FreeBSD Security Advisory FreeBSD-SA-21:12.libradius’ sudo with pam_radius has started to fail for us. It correctly seems to communicate with the RADIUS server (used to trigger MFA authentication, so I get an authentication popup in the Microsoft Authenticar App) after entering the unix password first, but then something fails:

% sudo su
Password:
sudo: PAM authentication error: Error in service module
sudo: a password is required


pam.d/sudo config file:

# auth
auth            requisite       pam_unix.so            no_warn try_first_pass
auth            requisite       pam_radius.so		use_first_pass

# account
account         include         system

# session
session         required        pam_permit.so

# password
password        include         system


Dunno if the problem is in sudo, libpam, libradius or pam_radius but the only thing changed is libradius. And if I replace libradius.so.4 with the previous version things work again...

(Considering the spagetti code that sudo is I wouldn’t be surprised if the bug is there but still…)


Am I the only one seeing this?

- Peter