Re: [RFCv2][PATCH 1/2] fs proc: make pagemap a privileged interface

From: Eric W. Biederman
Date: Tue Mar 17 2015 - 09:08:32 EST


Dave Hansen <dave@xxxxxxxx> writes:

> From: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
>
> Changes from v1:
> * Do not allow a child pid namespace to unset paranoid
> when its parent had it set.
> * Update description text to clarify the options we
> have to solve this problem.

Again.

Nacked-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>

The option name "paranoid" is entirely too general. Who knows what
it referrs to.

A mount option is not an appropriate place to control one small bit of
policy like this. Proc mount options are a real pain in the butt to
deal with and to maintain.

Further a per pid namespace decision does not actually work, for having
restricted policy only for a small set of processes because it is only
with very careful container setup that you would expose this policy.

If you really need a subset of processes with a restricted policy make
it a prctl, and bloat struct task. Then disallow a process with the
prctl set from reading the file.

Eric
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