Bug#384922: NFS insecure without support for squashing multiple groups

[paul.szabo@sydney.edu.au]

> ... AUTH_SYS with untrusted root on clients is not a good fit ...
> NFSv4 with kerberos authentication would be less broken.  root_squash
> is a simplistic and incomplete band-aid.

NFSv4+krb is better only because it does not have a concept of groups.
Remove groups from AUTH_SYS, ignoring all groups or in other words doing
"manage primary group" similar to secondaries with -manage_gids, and
issue might be solved.
(In that sense NFSv4+krb is more broken, less feature-rich, than
AUTH_SYS.)

Cheers, Paul

Paul Szabo   psz@maths.usyd.edu.au   http://www.maths.usyd.edu.au/u/psz/
School of Mathematics and Statistics   University of Sydney    Australia