linux-kernel - Re: [PATCH v6 0/2] enhance TPM 2.0 extend function to support multiple PCR banks

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Date:   Thu, 26 Jan 2017 20:04:24 +0530
From:   Nayna <nayna@...ux.vnet.ibm.com>
To:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Cc:     tpmdd-devel@...ts.sourceforge.net, peterhuewe@....de,
        tpmdd@...horst.net, jgunthorpe@...idianresearch.com,
        linux-security-module@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6 0/2] enhance TPM 2.0 extend function to support
 multiple PCR banks



On 01/26/2017 05:03 AM, Jarkko Sakkinen wrote:
> On Wed, Jan 25, 2017 at 10:45:35PM +0200, Jarkko Sakkinen wrote:
>> On Fri, Jan 20, 2017 at 12:05:11PM -0500, Nayna Jain wrote:
>>> IMA extends its hash measurements in the TPM PCRs, based on policy.
>>> The existing in-kernel TPM extend function extends only the SHA1
>>> PCR bank. TPM 2.0 defines multiple PCR banks, to support different
>>> hash algorithms. The TCG TPM 2.0 Specification[1] recommends
>>> extending all active PCR banks to prevent malicious users from
>>> setting unused PCR banks with fake measurements and quoting them.
>>> This patch set adds support for extending all active PCR banks,
>>> as recommended.
>>>
>>> The first patch implements the TPM 2.0 capability to retrieve
>>> the list of active PCR banks.
>>>
>>> The second patch modifies the tpm_pcr_extend() and tpm2_pcr_extend()
>>> interface to support extending multiple PCR banks. The existing
>>> tpm_pcr_extend() interface expects only a SHA1 digest. Hence, to
>>> extend all active PCR banks with differing digest sizes for TPM 2.0,
>>> the SHA1 digest is padded with 0's as needed.
>>>
>>> [1] TPM 2.0 Specification referred here is "TCG PC Client Specific
>>> Platform Firmware Profile for TPM 2.0"
>>
>> I pushed these patches. I had to resolve merge conflicts caused
>> by the min_rsp_body_length parameter in tpm_transmit_cmd. Can you
>> verify that I didn't break anything?
>
> You have a bug in tpm2_get_pcr_allocation:
>
> rc = tpm_transmit_cmd(chip, buf.data, PAGE_SIZE, 9, 0,
> 		      "get tpm pcr allocation");
> if (rc < 0)
> 	goto out;
>
> You do not handle TPM error. Can you send a fix for this ASAP?

Oh!! Sure..
I see below fix should handle it.
if (rc)
   goto out:

Sending the patch...

Thanks & Regards,
    - Nayna

>
> /Jarkko
>