[sudo-users] strange error for some users on AIX

[Todd C. Miller]

On Fri, 15 Jul 2016 13:17:56 +0200, Levente Szente wrote:

> users using kerberos authentication are receiving a strange error message
> when trying to run sudo on an AIX box part of a PowerHA cluster:
> $ sudo -l
> sudo: perm stack underflow: A system call received a parameter that is not
> valid.
> sudo: unknown uid: 113
> Segmentation fault
> 
> I have seen in the past the large userid could cause problems, but this is
> clearly not the case, the username has only two letters, but on other boxes
> is working, so that should also not be a problem.

The "perm stack underflow" bug was fixed in sudo 1.8.8.  It is
triggered by the "unknown uid 113" warning.  The real issue is that
sudo can't lookup uid 113 to find its name.

Are you runing the same version of sudo on the working AIX boxes?
Sudo 1.8.5p3 is somewhat old, I'd suggest trying 1.8.17 and see if
that resolves the problem.  You can find AIX packages at
https://www.sudo.ws/download.html#binary

 - todd