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Message-ID: <488442598c3703760ed6182426ed891f85fe0a1a.camel@linux.ibm.com>
Subject: Re: [PATCH v3] ima: detect changes to the backing overlay file
From:   Mimi Zohar <zohar@linux.ibm.com>
To:     Eric Snowberg <eric.snowberg@oracle.com>
Cc:     "linux-integrity@vger.kernel.org" <linux-integrity@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>,
        Raul Rangel <rrangel@chromium.org>,
        Amir Goldstein <amir73il@gmail.com>
Date:   Wed, 25 Oct 2023 14:01:15 -0400
In-Reply-To: <485C9C57-ABF1-4618-81D1-345597A1B9FA@oracle.com>
References: <20231025143906.133218-1-zohar@linux.ibm.com>
         <485C9C57-ABF1-4618-81D1-345597A1B9FA@oracle.com>
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On Wed, 2023-10-25 at 16:27 +0000, Eric Snowberg wrote:
> 
> > On Oct 25, 2023, at 8:39 AM, Mimi Zohar <zohar@linux.ibm.com> wrote:
> > 
> > Commit 18b44bc5a672 ("ovl: Always reevaluate the file signature for
> > IMA") forced signature re-evaulation on every file access.
> > 
> > Instead of always re-evaluating the file's integrity, detect a change
> > to the backing file, by comparing the cached file metadata with the
> > backing file's metadata.  Verifying just the i_version has not changed
> > is insufficient.  In addition save and compare the i_ino and s_dev
> > as well.
> > 
> > Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
> 
> I ran the file integrity tests that originally uncovered the need for 
> "Commit 18b44bc5a672 ("ovl: Always reevaluate the file signature for 
> IMA”). When the backing file is changed, file integrity remains.  For that 
> part, feel free to add:
> 
> Tested-by: Eric Snowberg <eric.snowberg@oracle.com>

Thanks!

Mimi