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Message-ID: <53a067f80db2e53ae29dc811515ab51c6ef86aed.camel@huaweicloud.com>
Subject: Re: [RFC PATCH v15 18/21] ipe: enable support for fs-verity as a
 trust provider
From: Roberto Sassu <roberto.sassu@huaweicloud.com>
To: Eric Biggers <ebiggers@kernel.org>, 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,  fsverity@lists.linux.dev,
 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>
Date: Mon, 18 Mar 2024 09:08:10 +0100
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On Sun, 2024-03-17 at 22:17 -0700, Eric Biggers wrote:
> On Fri, Mar 15, 2024 at 08:35:48PM -0700, Fan Wu wrote:
> > +config IPE_PROP_FS_VERITY
> > +	bool "Enable property for fs-verity files"
> > +	depends on FS_VERITY && FS_VERITY_BUILTIN_SIGNATURES
> > +	help
> > +	  This option enables the usage of properties "fsverity_signature"
> > +	  and "fsverity_digest". These properties evaluate to TRUE when
> > +	  a file is fsverity enabled and with a signed digest
>=20
> Again: why would anyone care if there is a signature, if that signature i=
s not
> checked.
>=20
> I think you meant to write something like: "when a file is fsverity enabl=
ed and
> has a valid builtin signature whose signing cert is in the .fs-verity key=
ring".

I was also thinking the same. I didn't follow the recent development
closely, but unless IPE locks somehow the .fs-verity keyring, the
property you suggested would not be immutable. Meaning that someone can
add/remove a key in that keyring, making the property true or false.

Roberto