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Subject: Re: [PATCH] KEYS: trusted: allow module init if TPM is inactive or
 deactivated
From:   Mimi Zohar <zohar@linux.ibm.com>
To:     Roberto Sassu <roberto.sassu@huawei.com>,
        Tyler Hicks <tyhicks@canonical.com>,
        Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc:     jejb@linux.ibm.com, jgg@ziepe.ca, linux-integrity@vger.kernel.org,
        linux-security-module@vger.kernel.org, keyrings@vger.kernel.org,
        linux-kernel@vger.kernel.org, crazyt2019+lml@gmail.com,
        nayna@linux.vnet.ibm.com, silviu.vlasceanu@huawei.com
Date:   Mon, 05 Aug 2019 11:54:19 -0400
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         <e50c4cfa-1f0c-6f4d-1910-010a8d874393@huawei.com>
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         <20190802202343.GE26616@elm>
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On Mon, 2019-08-05 at 16:50 +0200, Roberto Sassu wrote:
> Regarding Mimi's proposal to avoid the issue by extending the PCR with
> zeros, I think it also achieve the goal. 

Roberto, removing the following code from init_digests() would be the
equivalent to the prior code, without needing to make any other
changes.  Let's keep it simple.  Do you want to post the patch with
the change, or should I?

        ret = tpm_get_random(chip, digest, TPM_MAX_DIGEST_SIZE);
        if (ret < 0)
                return ret;
        if (ret < TPM_MAX_DIGEST_SIZE)
                return -EFAULT;

As I can't duplicate the problem, it would need to be tested by others
experiencing the problem.

thanks,

Mimi