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From: Kay Sievers <kay@vrfy.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kees Cook <keescook@chromium.org>,
	linux-kernel@vger.kernel.org, ellyjones@chromium.org
Subject: Re: [PATCH] devtmpfs: mount with noexec and nosuid
Date: Sat, 17 Nov 2012 01:39:02 +0100	[thread overview]
Message-ID: <CAPXgP12e5LpN6XVxaXOHhH=u8XXN==2reTaJDCoCk4tP4QduDQ@mail.gmail.com> (raw)
In-Reply-To: <20121117002753.GA22778@kroah.com>

On Sat, Nov 17, 2012 at 1:27 AM, Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
> On Fri, Nov 16, 2012 at 04:20:16PM -0800, Kees Cook wrote:
>> Since devtmpfs is writable, make the default noexec nosuid as well. This
>> protects from the case of a privileged process having an arbitrary file
>> write flaw and an argumentless arbitrary execution (i.e. it would lack
>> the ability to run "mount -o remount,exec,suid /dev"), with a system
>> that already has nosuid,noexec on all other writable mounts.
>>
>> Cc: ellyjones@chromium.org
>> Signed-off-by: Kees Cook <keescook@chromium.org>
>> ---
>>  drivers/base/devtmpfs.c |    6 ++++--
>>  1 file changed, 4 insertions(+), 2 deletions(-)
>
> Have you tested this to verify that it doesn't break anything?
>
> Kay, could this cause any problems that you could think of?

It breaks all sorts of old, possibly outdated, stuff, that does things
like mapping /dev/mem executable. It for sure used to break X drivers,
that fiddle with the BIOS of cards.

Kay

  parent reply	other threads:[~2012-11-17  0:39 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-11-17  0:20 [PATCH] devtmpfs: mount with noexec and nosuid Kees Cook
2012-11-17  0:27 ` Greg Kroah-Hartman
2012-11-17  0:34   ` Kees Cook
2012-11-17  0:39   ` Kay Sievers [this message]
2012-11-19 18:14     ` Kees Cook
2012-11-19 23:55       ` Roland Eggner
2021-12-22 12:50 Muhammad Usama Anjum

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