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References: <20180102232133.GA39880@beast> <20180103070444.GA6331@mail.hallyn.com>
 <20180103071158.204eeb41@tomh>
From: Kees Cook <keescook@chromium.org>
Date: Wed, 3 Jan 2018 09:21:41 -0800
Message-ID: <CAGXu5j+FrS0Hmc-SfagJ1O2F69MN8KUec4TVZ-v9_HtTws3bRA@mail.gmail.com>
Subject: Re: [PATCH] exec: Weaken dumpability for secureexec
To: Tom Horsley <horsley1953@gmail.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Laura Abbott <labbott@redhat.com>,
        David Howells <dhowells@redhat.com>,
        James Morris <james.l.morris@oracle.com>,
        LKML <linux-kernel@vger.kernel.org>
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Sender: linux-kernel-owner@vger.kernel.org

On Wed, Jan 3, 2018 at 4:11 AM, Tom Horsley <horsley1953@gmail.com> wrote:
> On Wed, 3 Jan 2018 01:04:44 -0600
> Serge E. Hallyn wrote:
>
>> > This weakens dumpability back to checking only for uid/gid changes in
>> > current (which is useless), but userspace depends on dumpability not
>> > being tied to secureexec.
>> >
>> > https://bugzilla.redhat.com/show_bug.cgi?id=1528633
>> >
>> > Reported-by: Tom Horsley <horsley1953@gmail.com>
>>
>> Seems right, any chance we could get a tested-by: Tom?  (Did we already
>> get that?)
>
> I didn't test it myself, but all I'd do is run the test program
> I've attached to the bugzilla above which is trivial compared
> to be learning how to patch and build kernels. So it would be
> much simpler for someone with the kernel already built to
> extract the tarball and type make :-).

This is what I did to verify it. Thank you very much for the test case!

-Kees

-- 
Kees Cook
Pixel Security