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

[Kees Cook]

On Mon, Mar 9, 2015 at 4:43 PM, Eric W. Biederman <ebiederm@xxxxxxxxxxxx> wrote:
>
> A 1 to 1 blinding function like integer multiplication mudulo 2^32 by an
> appropriate random number ought to keep from revealing page numbers or
> page ajacencies while not requiring any changes in userspace.
>
> That way the revealed pfn and the physcial pfn would be different but
> you could still use pagemap for it's intended purpose.

If this could be done in a way where it was sufficiently hard to
expose the random number, we should absolutely do this. And this could
be done for socket handles in INET_DIAG too. We have a lot of these
kinds of "handle" leaks where the handle's can be regarded as private
information leakage.

-Kees


-- 
Kees Cook
Chrome OS Security
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/