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

[ebiederm@xmission.com (Eric W. Biederman)]

Dave Hansen <dave@sr71.net> writes:

> From: Dave Hansen <dave.hansen@linux.intel.com>
>
> 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@xmission.com>

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