linux-kernel - Re: [PATCH v3 4/5] tpm: retrieve digest size of unknown algorithms with PCR read

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Message-ID: <3b198ce9-9e2e-5290-bd40-e9a62da1f50d@huawei.com>
Date:   Mon, 5 Nov 2018 14:09:12 +0100
From:   Roberto Sassu <roberto.sassu@...wei.com>
To:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
CC:     Mimi Zohar <zohar@...ux.ibm.com>,
        <linux-integrity@...r.kernel.org>,
        <linux-security-module@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <silviu.vlasceanu@...wei.com>
Subject: Re: [PATCH v3 4/5] tpm: retrieve digest size of unknown algorithms
 with PCR read

On 11/5/2018 1:01 PM, Jarkko Sakkinen wrote:
> On Mon, Nov 05, 2018 at 10:47:19AM +0100, Roberto Sassu wrote:
>>> Commit 1db15344f874 ("tpm: implement TPM 2.0 capability to get active
>>> PCR banks") defined active_banks[7].  Subsequently, commit
>>> 4d23cc323cdb ("tpm: add securityfs support for TPM 2.0 firmware event
>>> log") defined TPM2_PCR_ACTIVE_BANKS as 3.  I'm not sure which is the
>>> correct value, but the number of active_banks should not be hard coded
>>> here.
>>
>> Jarkko, should I change the value of TPM2_PCR_ACTIVE_BANKS, or set the
>> size of the active_banks array to TPM2_PCR_ACTIVE_BANKS?
> 
> Hi, sorry I missed your patch set. Please add me either to 'To' or 'Cc'
> field of the email if you want a quick response.
> 
> I think the implementation is flakky in both places and should be fixed
> before doing any other changes. Thanks James for pointing out these
> commits.
> 
> What you need to do is to create a prequel commit that reads the number
> of banks to a variable e.g.
> 
>    unsigned int nr_active_banks;
> 
> and allocate 'active_banks' dynamically and change the places that
> James pointed out. I guess it is OK to have a commit with two 'Fixes'
> tags.

Ok, then I can remove patch 1/5 if nr_active_banks is included in the
tpm_chip structure.

Roberto


> /Jarkko
> 

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