linux-kernel - Re: [kernel-hardening] Re: [RFC v4 PATCH 00/13] HARDENED

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Date:   Thu, 10 Nov 2016 23:25:08 -0500
From:   Rik van Riel <riel@...hat.com>
To:     kernel-hardening@...ts.openwall.com,
        Peter Zijlstra <peterz@...radead.org>
Cc:     Will Deacon <will.deacon@....com>,
        Elena Reshetova <elena.reshetova@...el.com>,
        Arnd Bergmann <arnd@...db.de>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <h.peter.anvin@...el.com>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [kernel-hardening] Re: [RFC v4 PATCH 00/13] HARDENED_ATOMIC

On Thu, 2016-11-10 at 13:23 -0800, Kees Cook wrote:

> If we don't use opt-out for atomics, we're going to be in the same
> situation where we have to constantly review every commit with an
> atomic for exploitable refcount flaws. Kicking this down from
> "privilege escalation" to "DoS" is a significant change in the
> kernel's weaknesses.

The only way I see around that would be to totally get
rid of the name atomic_t, forcing people with out of
tree code to use kref_t, or whatever name we pick for
the variable type that can wrap.

Something like checkpatch or a patch checking bot
could warn whenever new code is submitted that uses
the counter type that can wrap.

Not sure whether I like my idea :)

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