From: Mimi Zohar <zohar@linux.ibm.com>
To: Eric Biggers <ebiggers@kernel.org>
Cc: linux-integrity@vger.kernel.org, linux-fscrypt@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/4] ima: define a new signature type named IMA_VERITY_DIGSIG
Date: Tue, 30 Nov 2021 13:14:11 -0500 [thread overview]
Message-ID: <6931ed7b1c7d5906bb595447fc24cd8a9b3e3d62.camel@linux.ibm.com> (raw)
In-Reply-To: <YaWNX3nwslG/Q2aH@sol.localdomain>
On Mon, 2021-11-29 at 18:33 -0800, Eric Biggers wrote:
> On Mon, Nov 29, 2021 at 12:00:55PM -0500, Mimi Zohar wrote:
> > To differentiate between a regular file hash and an fs-verity file digest
> > based signature stored as security.ima xattr, define a new signature type
> > named IMA_VERITY_DIGSIG.
> >
> > Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
>
> For this new signature type, what bytes are actually signed? It looks like it's
> just the raw digest, which isn't sufficient since it is ambiguous. It needs to
> include information that makes it clear what the signer is actually signing,
> such as "this is an fs-verity SHA-256 file digest". See
> 'struct fsverity_formatted_digest' for an example of this (but it isn't
> necessary to use that exact structure).
>
> I think the existing IMA signatures have the same problem (but it is hard for me
> to understand the code). However, a new signature type doesn't have
> backwards-compatibility concerns, so it could be done right.
As this change should probably be applicable to all signature types,
the signature version in the signature_v2_hdr should be bumped. The
existing signature version could co-exist with the new signature
version.
thanks,
Mimi
next prev parent reply other threads:[~2021-11-30 18:14 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-29 17:00 [PATCH 0/4] ima: support fs-verity signatures stored as Mimi Zohar
2021-11-29 17:00 ` [PATCH 1/4] fs-verity: define a function to return the integrity protected file digest Mimi Zohar
2021-11-29 23:16 ` kernel test robot
2021-11-29 23:36 ` kernel test robot
2021-11-30 2:19 ` Eric Biggers
2021-11-30 5:33 ` Lakshmi Ramasubramanian
2021-11-30 6:30 ` Eric Biggers
2021-11-29 17:00 ` [PATCH 2/4] ima: define a new signature type named IMA_VERITY_DIGSIG Mimi Zohar
2021-11-30 2:33 ` Eric Biggers
2021-11-30 18:14 ` Mimi Zohar [this message]
2021-12-02 16:25 ` Mimi Zohar
2021-12-02 21:17 ` Eric Biggers
2021-12-02 21:56 ` Mimi Zohar
2021-11-29 17:00 ` [PATCH 3/4] ima: limit including fs-verity's file digest in measurement list Mimi Zohar
2021-11-30 2:35 ` Eric Biggers
2021-11-30 13:15 ` Mimi Zohar
2021-11-30 5:46 ` Lakshmi Ramasubramanian
2021-11-29 17:00 ` [PATCH 4/4] ima: support fs-verity file digest based signatures Mimi Zohar
2021-11-30 5:56 ` Lakshmi Ramasubramanian
2021-11-30 13:36 ` Mimi Zohar
2021-11-30 2:36 ` [PATCH 0/4] ima: support fs-verity signatures stored as Eric Biggers
2021-11-30 12:56 ` Mimi Zohar
2021-11-30 22:49 ` Mimi Zohar
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