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From: Amir Goldstein <amir73il@gmail.com>
Date: Tue, 23 Apr 2024 09:02:58 +0300
Message-ID: <CAOQ4uxgvHjU-n56ryOp5yWQF=yKz0Cfo0ZieypWJhqsBV4g-2w@mail.gmail.com>
Subject: Re: [RFC PATCH v2 0/2] ima: Fix detection of read/write violations on
 stacked filesystems
To: Stefan Berger <stefanb@linux.ibm.com>
Cc: linux-integrity@vger.kernel.org, linux-unionfs@vger.kernel.org, 
	linux-kernel@vger.kernel.org, zohar@linux.ibm.com, roberto.sassu@huawei.com, 
	miklos@szeredi.hu, brauner@kernel.org
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On Mon, Apr 22, 2024 at 6:07=E2=80=AFPM Stefan Berger <stefanb@linux.ibm.co=
m> wrote:
>
> This series fixes the detection of read/write violations on stacked
> filesystems. To be able to access the relevant dentries necessary to
> detect files opened for writing on a stacked filesystem a new d_real_type
> D_REAL_FILEDATA is introduced that allows callers to access all relevant
> files involved in a stacked filesystem while traversing the layers.
>

Stefan,

Both Miklos and myself objected to this solution:
https://lore.kernel.org/linux-unionfs/CAJfpeguctirEYECoigcAsJwpGPCX2NyfMZ8H=
8GHGW-0UyKfjgg@mail.gmail.com/

Not sure what you are hoping to achieve from re-posting the same solution.

I stopped counting how many times I already argued that *all* IMA/EVM
assertions,
including rw-ro violations should be enforced only on the real inode.
I know this does not work - so you should find out why it does not work and=
 fix
the problem.

Enforcing IMA/EVM on the overlayfs inode layer is just the wrong way IMO.
Not once have I heard an argument from IMA/EVM developers why it is really
needed to enforce IMA/EVM on the overlayfs inode layer and not on the
real inode.
I am sorry that we are failing to communicate on this matter, but I am not
sure how else I can help.

Thanks,
Amir.