linux-kernel - Re: [PATCH] devcoredump: provide a one-way disable function

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Message-ID: <CAGXu5jLATjeNN_DnTgU7=42hezXx3O+tH2_kgKAou9dweVnjvQ@mail.gmail.com>
Date:	Thu, 13 Nov 2014 15:35:56 -0800
From:	Kees Cook <keescook@...gle.com>
To:	Johannes Berg <johannes@...solutions.net>
Cc:	Greg Kroah-Hartmann <gregkh@...ux-foundation.org>,
	LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] devcoredump: provide a one-way disable function

On Thu, Nov 13, 2014 at 2:36 PM, Johannes Berg
<johannes@...solutions.net> wrote:
> On Thu, 2014-11-13 at 13:56 -0800, Kees Cook wrote:
>
>> > +       /*
>> > +        * This essentially makes the attribute write-once, since you can't
>> > +        * go back to not having it disabled. This is intentional, it serves
>> > +        * as a system lockdown feature.
>> > +        */
>> > +       if (tmp != 1)
>> > +               return -EINVAL;
>>
>> Just a nit, but writing "0" is valid if devcd_disabled = false?
>
> I thought about that too, but what would the point be? The only
> operation you ever can/want to do is writing "1" to it to disable the
> framework.

Yup, seems like not a useful thing to do, but figured I'd point it out
just in case. I think the patch is fine as-is.

-Kees

-- 
Kees Cook
Chrome OS Security
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