linux-kernel - Re: [PATCH 0/3] block: sed-opal: add support for shadow MBR done flag and write

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Date:   Sun, 5 May 2019 10:43:30 -0400
From:   Scott Bauer <sbauer@...donthack.me>
To:     David Kozub <zub@...ux.fjfi.cvut.cz>
Cc:     Christoph Hellwig <hch@...radead.org>,
        Jens Axboe <axboe@...nel.dk>,
        Jonathan Derrick <jonathan.derrick@...el.com>,
        linux-block@...r.kernel.org, linux-kernel@...r.kernel.org,
        Jonas Rabenstein <jonas.rabenstein@...dium.uni-erlangen.de>
Subject: Re: [PATCH 0/3] block: sed-opal: add support for shadow MBR done
 flag and write

On Fri, May 03, 2019 at 10:32:19PM +0200, David Kozub wrote:
> On Wed, 1 May 2019, Christoph Hellwig wrote:
> 
> > > I successfully tested toggling the MBR done flag and writing the shadow MBR
> > > using some tools I hacked together[4] with a Samsung SSD 850 EVO drive.
> > 
> > Can you submit the tool to util-linux so that we get it into distros?
> 
> There is already Scott's sed-opal-temp[1] and a fork by Jonas that adds
> support for older version of these new IOCTLs[2]. There was already some
> discussion of getting that to util-linux.[3]
> 
> While I like my hack, sed-opal-temp can do much more (my tool supports just
> the few things I actually use). But there are two things which sed-opal-temp
> currently lacks which my hack has:
> 
> * It can use a PBKDF2 hash (salted by disk serial number) of the password
>   rather than the password directly. This makes it compatible with sedutil
>   and I think it's also better practice (as firmware can contain many
>   surprises).
> 
> * It contains a 'PBA' (pre-boot authorization) tool. A tool intended to be
>   run from shadow mbr that asks for a password and uses it to unlock all
>   disks and set shadow mbr done flag, so after restart the computer boots
>   into the real OS.
> 
> @Scott: What are your plans with sed-opal-temp? If you want I can update
> Jonas' patches to the adapted IOCTLs. What are your thoughts on PW hashing
> and a PBA tool?

I will accept any and all patches to sed opal tooling, I am not picky. I will
also give up maintainership of it is someone else feels they can (rightfully
so) do a better job.

Jon sent me a patch for the tool that will deal with writing to the shadow MBR,
so once we know these patches are going in i'll pull that patch into the tool.

Then I guess that leaves PBKDF2 which I don't think will be too hard to pull in.

With regard to your PBA tool, is that actually being run post-uefi/pre-linux?
IE are we writing your tool into the SMBR and that's what is being run on bootup?

Jon, if you think it's a good idea can you ask David if Revanth or you wants
to take over the tooling? Or if anyone else here wants to own it then let me know.