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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:     Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>,
        James Bottomley <jejb@linux.ibm.com>
Cc:     Roberto Sassu <roberto.sassu@huawei.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,
        tyhicks@canonical.com, nayna@linux.vnet.ibm.com,
        silviu.vlasceanu@huawei.com
Date:   Tue, 09 Jul 2019 12:31:45 -0400
In-Reply-To: <20190709162458.f4fjteokcmidv7w6@linux.intel.com>
References: <20190705163735.11539-1-roberto.sassu@huawei.com>
         <1562618099.20748.13.camel@linux.ibm.com>
         <20190709162458.f4fjteokcmidv7w6@linux.intel.com>
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On Tue, 2019-07-09 at 19:24 +0300, Jarkko Sakkinen wrote:
> On Mon, Jul 08, 2019 at 01:34:59PM -0700, James Bottomley wrote:
> > Not a criticism of your patch, but can we please stop doing this. 
> > Single random number sources are horrendously bad practice because it
> > gives an attacker a single target to subvert.  We should ensure the TPM
> > is plugged into the kernel RNG as a source and then take randomness
> > from the mixed pool so it's harder for an attacker because they have to
> > subvert all our sources to predict what came out.
> 
> It is and I agree.

I still haven't quite figured out why the digests need to be
initialized to anything other than 0.

Mimi