From: Kees Cook <keescook@chromium.org>
To: Matthias Kaehlcke <mka@chromium.org>
Cc: Alasdair Kergon <agk@redhat.com>,
Mike Snitzer <snitzer@kernel.org>,
James Morris <jmorris@namei.org>,
"Serge E . Hallyn" <serge@hallyn.com>,
dm-devel@redhat.com, linux-kernel@vger.kernel.org,
linux-raid@vger.kernel.org, Song Liu <song@kernel.org>,
Douglas Anderson <dianders@chromium.org>,
linux-security-module@vger.kernel.org
Subject: Re: [PATCH v3 1/3] dm: Add verity helpers for LoadPin
Date: Mon, 16 May 2022 20:38:12 -0700 [thread overview]
Message-ID: <202205162035.CABA5B2C6@keescook> (raw)
In-Reply-To: <YoKdSrjVf/tHGoa5@google.com>
On Mon, May 16, 2022 at 11:51:54AM -0700, Matthias Kaehlcke wrote:
> 'targets' are different types of DM mappings like 'linear' or 'verity'. A
> device mapper table contains has one or more targets that define the mapping
> of the blocks of the mapped device.
>
> Having spelled that out I realize that the above check is wrong. It would
> consider a device like this trusted:
>
> 0 10000000 linear 8:1
> 10000000 10001000 verity <params>
>
> In the above case only a small part of the DM device would be backed by verity.
>
> I think we want a table with a single entry that is a verity target.
Ah-ha! Okay, that's what I was worried about. Yes, a device made up
of only trusted verity targets should be the only trusted device. (So,
technically it could be more than 1 verity target, but each would need
to be trusted. Supporting that arrangement, though, may be overkill --
I would expect a 1:1 mapping as you suggest.
--
Kees Cook
next prev parent reply other threads:[~2022-05-17 3:38 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-04 19:54 [PATCH v3 0/3] LoadPin: Enable loading from trusted dm-verity devices Matthias Kaehlcke
2022-05-04 19:54 ` [PATCH v3 1/3] dm: Add verity helpers for LoadPin Matthias Kaehlcke
2022-05-11 20:54 ` Matthias Kaehlcke
2022-05-12 17:19 ` Mike Snitzer
2022-05-12 18:14 ` Matthias Kaehlcke
2022-05-12 20:44 ` Matthias Kaehlcke
2022-05-13 16:29 ` Mike Snitzer
2022-05-13 16:53 ` Matthias Kaehlcke
2022-05-13 22:15 ` Kees Cook
2022-05-16 18:51 ` Matthias Kaehlcke
2022-05-17 3:38 ` Kees Cook [this message]
2022-05-04 19:54 ` [PATCH v3 2/3] LoadPin: Enable loading from trusted dm-verity devices Matthias Kaehlcke
2022-05-04 22:26 ` kernel test robot
2022-05-13 16:32 ` Mike Snitzer
2022-05-13 17:01 ` Matthias Kaehlcke
2022-05-13 18:26 ` Kees Cook
2022-05-13 22:36 ` Kees Cook
2022-05-16 18:17 ` Matthias Kaehlcke
2022-05-17 3:44 ` Kees Cook
2022-05-17 19:28 ` Matthias Kaehlcke
2022-05-04 19:54 ` [PATCH v3 3/3] dm: verity-loadpin: Use CONFIG_SECURITY_LOADPIN_VERITY for conditional compilation Matthias Kaehlcke
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