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Date:   Tue, 25 Jun 2019 14:20:04 -0400
From:   Mike Snitzer <snitzer@redhat.com>
To:     Jaskaran Khurana <jaskarankhurana@linux.microsoft.com>,
        gmazyland@gmail.com
Cc:     linux-security-module@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-integrity@vger.kernel.org,
        linux-fsdevel@vger.kernel.org, scottsh@microsoft.com,
        ebiggers@google.com, jmorris@namei.org, dm-devel@redhat.com,
        mpatocka@redhat.com, agk@redhat.com
Subject: Re: [RFC PATCH v5 1/1] Add dm verity root hash pkcs7 sig validation.
Message-ID: <20190625182004.GA32075@redhat.com>
References: <20190619191048.20365-1-jaskarankhurana@linux.microsoft.com>
 <20190619191048.20365-2-jaskarankhurana@linux.microsoft.com>
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On Wed, Jun 19 2019 at  3:10pm -0400,
Jaskaran Khurana <jaskarankhurana@linux.microsoft.com> wrote:

> The verification is to support cases where the roothash is not secured by
> Trusted Boot, UEFI Secureboot or similar technologies.
> One of the use cases for this is for dm-verity volumes mounted after boot,
> the root hash provided during the creation of the dm-verity volume has to
> be secure and thus in-kernel validation implemented here will be used
> before we trust the root hash and allow the block device to be created.
> 
> The signature being provided for verification must verify the root hash and
> must be trusted by the builtin keyring for verification to succeed.
> 
> The hash is added as a key of type "user" and the description is passed to 
> the kernel so it can look it up and use it for verification.
> 
> Kernel commandline parameter will indicate whether to check (only if 
> specified) or force (for all dm verity volumes) roothash signature 
> verification.
> 
> Kernel commandline: dm_verity.verify_sig=1 or 2 for check/force root hash
> signature validation respectively.
> 
> Signed-off-by: Jaskaran Khurana <jaskarankhurana@linux.microsoft.com>

Milan and/or others: could you please provide review and if you're OK
with this patch respond accordingly?

Thanks,
Mike