Date:   Tue, 31 Jan 2023 15:01:00 -0800
From:   Fan Wu <wufan@linux.microsoft.com>
To:     Christoph Hellwig <hch@infradead.org>
Cc:     corbet@lwn.net, zohar@linux.ibm.com, jmorris@namei.org,
        serge@hallyn.com, tytso@mit.edu, ebiggers@kernel.org,
        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@redhat.com, linux-audit@redhat.com,
        roberto.sassu@huawei.com, linux-kernel@vger.kernel.org,
        Deven Bowers <deven.desai@linux.microsoft.com>
Subject: Re: [RFC PATCH v9 09/16] block|security: add LSM blob to block_device
Message-ID: <20230131230100.GA30104@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net>
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On Tue, Jan 31, 2023 at 12:53:59AM -0800, Christoph Hellwig wrote:
> On Mon, Jan 30, 2023 at 02:57:24PM -0800, Fan Wu wrote:
> > From: Deven Bowers <deven.desai@linux.microsoft.com>
> > 
> > block_device structures can have valuable security properties,
> > based on how they are created, and what subsystem manages them.
> 
> That's a lot of cloudy talk but no real explanation.

Sorry for being too general here. Currently the only use target of this hook is dm-verity. We use the newly added security hook to save the dm-verity roothash and signature to the new bdev security blob during the bdev creation time, so LSMs can leverage this information to protect the system. 

I will add this example in the next version.

-Fan