From: Eric Biggers <ebiggers@kernel.org>
To: Fan Wu <wufan@linux.microsoft.com>
Cc: corbet@lwn.net, zohar@linux.ibm.com, jmorris@namei.org,
serge@hallyn.com, tytso@mit.edu, axboe@kernel.dk, agk@redhat.com,
snitzer@kernel.org, eparis@redhat.com, paul@paul-moore.com,
linux-doc@vger.kernel.org, linux-integrity@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-fscrypt@vger.kernel.org, linux-block@vger.kernel.org,
dm-devel@lists.linux.dev, audit@vger.kernel.org,
linux-kernel@vger.kernel.org,
Deven Bowers <deven.desai@linux.microsoft.com>
Subject: Re: [RFC PATCH v13 17/20] ipe: enable support for fs-verity as a trust provider
Date: Thu, 29 Feb 2024 11:42:37 -0800 [thread overview]
Message-ID: <20240229194237.GA1454@sol.localdomain> (raw)
In-Reply-To: <b73e3387-558f-4f40-8741-c6ed7965b25f@linux.microsoft.com>
On Thu, Feb 29, 2024 at 10:59:21AM -0800, Fan Wu wrote:
> >
> > So IPE is interested in whether a file has an fsverity builtin signature, but it
> > doesn't care what the signature is or whether it has been checked. What is the
> > point?
> >
> > - Eric
>
> It does make sure the signature is checked. This hook call can only be
> triggered after fsverity_verify_signature() succeed. Therefore, for files
> that are marked with the security blob inode_sec->fs_verity_sign as true,
> they must successfully pass the fsverity_verify_signature() check.
>
> Regarding the other question, the current version does not support defining
> policies to trust files based on the inner content of their signatures
> because the current patch set is already too large.
>
> We plan to introduce new policy grammars to enable the policy to define
> which certificate of the signature can be trusted after this version is
> accepted.
Ah, I see, you're relying on the fact that fsverity_verify_signature() verifies
the signature (if present) even if fs.verity.require_signatures hasn't been set.
That does happen to be its behavior, but this isn't clearly documented since
there previously wasn't really a use case for the builtin signatures without
setting fs.verity.require_signatures. Can you please make sure this behavior is
documented properly in Documentation/filesystems/fsverity.rst and in function
comments? Otherwise I worry that it could get changed and break your code.
- Eric
next prev parent reply other threads:[~2024-02-29 19:42 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-29 0:54 [RFC PATCH v13 00/20] Integrity Policy Enforcement LSM (IPE) Fan Wu
2024-02-29 0:54 ` [RFC PATCH v13 01/20] security: add ipe lsm Fan Wu
2024-02-29 0:54 ` [RFC PATCH v13 02/20] ipe: add policy parser Fan Wu
2024-02-29 0:54 ` [RFC PATCH v13 03/20] ipe: add evaluation loop Fan Wu
2024-02-29 0:54 ` [RFC PATCH v13 04/20] ipe: add LSM hooks on execution and kernel read Fan Wu
2024-02-29 0:54 ` [RFC PATCH v13 05/20] initramfs|security: Add a security hook to do_populate_rootfs() Fan Wu
2024-02-29 0:54 ` [RFC PATCH v13 06/20] ipe: introduce 'boot_verified' as a trust provider Fan Wu
2024-02-29 0:54 ` [RFC PATCH v13 07/20] security: add new securityfs delete function Fan Wu
2024-02-29 0:54 ` [RFC PATCH v13 08/20] ipe: add userspace interface Fan Wu
2024-02-29 0:54 ` [RFC PATCH v13 09/20] uapi|audit|ipe: add ipe auditing support Fan Wu
2024-02-29 0:54 ` [RFC PATCH v13 10/20] ipe: add permissive toggle Fan Wu
2024-02-29 0:54 ` [RFC PATCH v13 11/20] block|security: add LSM blob to block_device Fan Wu
2024-02-29 0:54 ` [RFC PATCH v13 12/20] dm verity: set DM_TARGET_SINGLETON feature flag Fan Wu
2024-03-02 16:01 ` Mike Snitzer
2024-02-29 0:54 ` [RFC PATCH v13 13/20] dm: add finalize hook to target_type Fan Wu
2024-03-02 16:13 ` Mike Snitzer
2024-02-29 0:54 ` [RFC PATCH v13 14/20] dm verity: consume root hash digest and signature data via LSM hook Fan Wu
2024-03-02 16:22 ` Mike Snitzer
2024-03-02 16:37 ` Mike Snitzer
2024-02-29 0:54 ` [RFC PATCH v13 15/20] ipe: add support for dm-verity as a trust provider Fan Wu
2024-02-29 0:54 ` [RFC PATCH v13 16/20] fsverity: consume builtin signature via LSM hook Fan Wu
2024-02-29 0:54 ` [RFC PATCH v13 17/20] ipe: enable support for fs-verity as a trust provider Fan Wu
2024-02-29 4:01 ` Randy Dunlap
2024-02-29 4:46 ` Eric Biggers
2024-02-29 18:59 ` Fan Wu
2024-02-29 19:42 ` Eric Biggers [this message]
2024-02-29 19:59 ` Fan Wu
2024-02-29 0:55 ` [RFC PATCH v13 18/20] scripts: add boot policy generation program Fan Wu
2024-02-29 0:55 ` [RFC PATCH v13 19/20] ipe: kunit test for parser Fan Wu
2024-02-29 0:55 ` [RFC PATCH v13 20/20] documentation: add ipe documentation Fan Wu
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