DM_INTEGRITY Kconfig help (was: Re: dm: add integrity target)
From: Geert Uytterhoeven
Date: Thu May 04 2017 - 02:03:50 EST
On Wed, May 3, 2017 at 7:43 PM, Linux Kernel Mailing List
> Web: https://git.kernel.org/torvalds/c/7eada909bfd7ac90a4522e56aa3179d1fd68cd14
> Commit: 7eada909bfd7ac90a4522e56aa3179d1fd68cd14
> Parent: 400a0befc96240f7bb2a53b9622deffd55d385fe
> Refname: refs/heads/master
> Author: Mikulas Patocka <mpatocka@xxxxxxxxxx>
> AuthorDate: Wed Jan 4 20:23:53 2017 +0100
> Committer: Mike Snitzer <snitzer@xxxxxxxxxx>
> CommitDate: Fri Mar 24 15:49:07 2017 -0400
> dm: add integrity target
> The dm-integrity target emulates a block device that has additional
> per-sector tags that can be used for storing integrity information.
> A general problem with storing integrity tags with every sector is that
> writing the sector and the integrity tag must be atomic - i.e. in case of
> crash, either both sector and integrity tag or none of them is written.
> To guarantee write atomicity the dm-integrity target uses a journal. It
> writes sector data and integrity tags into a journal, commits the journal
> and then copies the data and integrity tags to their respective location.
> The dm-integrity target can be used with the dm-crypt target - in this
> situation the dm-crypt target creates the integrity data and passes them
> to the dm-integrity target via bio_integrity_payload attached to the bio.
> In this mode, the dm-crypt and dm-integrity targets provide authenticated
> disk encryption - if the attacker modifies the encrypted device, an I/O
> error is returned instead of random data.
> The dm-integrity target can also be used as a standalone target, in this
> mode it calculates and verifies the integrity tag internally. In this
> mode, the dm-integrity target can be used to detect silent data
> corruption on the disk or in the I/O path.
> Signed-off-by: Mikulas Patocka <mpatocka@xxxxxxxxxx>
> Signed-off-by: Milan Broz <gmazyland@xxxxxxxxx>
> Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx>
> --- a/drivers/md/Kconfig
> +++ b/drivers/md/Kconfig
> @@ -500,4 +500,14 @@ config DM_LOG_WRITES
> If unsure, say N.
> +config DM_INTEGRITY
> + tristate "Integrity target"
> + depends on BLK_DEV_DM
> + select BLK_DEV_INTEGRITY
> + select DM_BUFIO
> + select CRYPTO
> + select ASYNC_XOR
> + ---help---
> + This is the integrity target.
Can you please extend the help message for the uneducated?
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds