linux-kernel - Re: [PATCH] overlayfs: Trigger file re-evaluation by IMA / EVM after writes

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Date:   Thu, 6 Apr 2023 15:11:37 -0400
From:   Stefan Berger <stefanb@...ux.ibm.com>
To:     Jeff Layton <jlayton@...nel.org>,
        Christian Brauner <brauner@...nel.org>,
        Paul Moore <paul@...l-moore.com>
Cc:     zohar@...ux.ibm.com, linux-integrity@...r.kernel.org,
        miklos@...redi.hu, linux-kernel@...r.kernel.org,
        linux-security-module@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, linux-unionfs@...r.kernel.org,
        amir73il@...il.com
Subject: Re: [PATCH] overlayfs: Trigger file re-evaluation by IMA / EVM after
 writes



On 4/6/23 14:46, Jeff Layton wrote:
> On Thu, 2023-04-06 at 17:01 +0200, Christian Brauner wrote:
>> On Thu, Apr 06, 2023 at 10:36:41AM -0400, Paul Moore wrote:

> 
> Correct. As long as IMA is also measuring the upper inode then it seems
> like you shouldn't need to do anything special here.

Unfortunately IMA does not notice the changes. With the patch provided in the other email IMA works as expected.

>
> What sort of fs are you using for the upper layer?

jffs2:

/dev/mtdblock4 on /run/initramfs/ro type squashfs (ro,relatime,errors=continue)
/dev/mtdblock5 on /run/initramfs/rw type jffs2 (rw,relatime)
cow on / type overlay (rw,relatime,lowerdir=run/initramfs/ro,upperdir=run/initramfs/rw/cow,workdir=run/initramfs/rw/work)

Regards,
    Stefan