linux-kernel - Re: [PATCH v5 6/7] tpm: ensure that the output of PCR read contains the correct digest size

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Message-ID: <05c7c936-da58-f386-0a43-69e96d6e18a8@huawei.com>
Date:   Fri, 16 Nov 2018 17:06:48 +0100
From:   Roberto Sassu <roberto.sassu@...wei.com>
To:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
CC:     <zohar@...ux.ibm.com>, <david.safford@...com>,
        <monty.wiseman@...com>, <linux-integrity@...r.kernel.org>,
        <linux-security-module@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <silviu.vlasceanu@...wei.com>,
        <stable@...r.kernel.org>
Subject: Re: [PATCH v5 6/7] tpm: ensure that the output of PCR read contains
 the correct digest size

On 11/16/2018 2:41 PM, Jarkko Sakkinen wrote:
> On Wed, Nov 14, 2018 at 04:31:07PM +0100, Roberto Sassu wrote:
>> This patch protects against data corruption that could happen in the bus,
>> by checking that that the digest size returned by the TPM during a PCR read
>> matches the size of the algorithm passed to tpm2_pcr_read().
>>
>> This check is performed after information about the PCR banks has been
>> retrieved.
>>
>> Signed-off-by: Roberto Sassu <roberto.sassu@...wei.com>
>> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
>> Cc: stable@...r.kernel.org
> 
> Missing fixes tag.

Before this patch set, tpm2_pcr_extend() always copied 20 bytes from the
output sent by the TPM.

Roberto


> /Jarkko
> 

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