Subject: Re: [PATCH 00/14] EVM
From: Mimi Zohar <zohar@linux.vnet.ibm.com>
To: Shaz <shazalive@gmail.com>
Cc: Dmitry Kasatkin <dmitry.kasatkin@nokia.com>,
       James Morris <jmorris@namei.org>,
       "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
       "linux-security-module@vger.kernel.org" 
	<linux-security-module@vger.kernel.org>,
       David Safford <safford@watson.ibm.com>,
       Dave Hansen <dave@linux.vnet.ibm.com>,
       Arjan van de Ven <arjan@infradead.org>,
       securityengineeringresearchgroup 
	<securityengineeringresearchgroup@googlegroups.com>
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Date: Fri, 04 Jun 2010 11:09:18 -0400
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On Fri, 2010-06-04 at 11:53 +0500, Shaz wrote:
> > Yes, verifying one file containing the hashes would be faster than
> > verifying individual hashes stored as extended attributes (xattrs), but
> > this does not take into account that files on a running system are being
> > modified or added. On a small form factor, the number of files is
> > limited, but would this scale well? In addition, what protects that one
> > file containing all the hashes from being modified?  So, if you limit
> 
> How about sealing to protect this file?

Was just indicating that the file needs to be protected. So, yes sealing
the file, based on PCRs, would work in a trusted boot environment.

> > the types of files to those that don't change, and the number of file
> > hashes, then using a single file would be faster.

Mimi


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