Re: [PATCH] leaking_addresses: add 32-bit support
From: Tobin C. Harding
Date: Tue Jan 30 2018 - 00:11:50 EST
On Tue, Jan 30, 2018 at 09:14:49AM +0530, kaiwan.billimoria@xxxxxxxxx wrote:
> Hi Tobin,
>
> On Mon, 2018-01-29 at 15:51 +1100, Tobin C. Harding wrote:
> > Currently script only supports x86_64 and ppc64. It would be nice to be
> > able to scan 32-bit machines also. We can add support for
> > 32-bit architectures by modifying how we check for false positives,
> > taking advantage of the page offset used by the kernel, and using the
> > correct regular expression.
> >
> > Support for 32-bit machines is enabled by the observation the kernel
> > addresses on 32-bit machines are larger than the page offset. We can
> > use this to filter false positives when scanning the kernel for leaking
> > addresses.
> >
> > Programmatic determination of the running architecture is not
> > immediately obvious. We therefore provide a flag to enable scanning of
> > 32-bit kernels. Also we can check the kernel config file for the offset
> > and if not found default to 0xc0000000. A command line option to parse
> > in the page offset is also provided. We do automatically detect
> > architecture if running on ix86.
> >
> > Add support for 32-bit kernels. Add a command line option for page
> > offset.
> >
> > Suggested-by: Kaiwan N Billimoria <kaiwan.billimoria@xxxxxxxxx>
> > Signed-off-by: Tobin C. Harding <me@xxxxxxxx>
> > ---
> >
> > The basis for this patch has been in development for a while by Kaiwan
> > but didn't get finished before the merge window opened. I'd like to
> > fast track this and get it to Linus this merge window (considering
> > Spectre/Meltdown). I have finished this work off and added the
> > Suggested-by tag. Kaiwan I hope you are not upset by this, extra
> > ordinary circumstances seemed to require this action.
> Definitely not; I understand and am glad you're on it a 100%. Apologies
> that I couldn't work on this right now.. will try and keep track too.
Thanks for the response.
Tobin