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Date: Tue, 14 May 2024 17:00:23 +0300
Message-Id: <D19F74M6B8UC.2VEOOZHGOS87V@kernel.org>
Cc: "James Bottomley" <James.Bottomley@hansenpartnership.com>, "Mimi Zohar"
 <zohar@linux.ibm.com>, "David Howells" <dhowells@redhat.com>, "Paul Moore"
 <paul@paul-moore.com>, "James Morris" <jmorris@namei.org>,
 <serge@hallyn.com>, <linux-integrity@vger.kernel.org>,
 <keyrings@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
 <kernel-team@cloudflare.com>
Subject: Re: [RFC PATCH 0/2] TPM derived keys
From: "Jarkko Sakkinen" <jarkko@kernel.org>
To: "Ignat Korchagin" <ignat@cloudflare.com>
References: <20240503221634.44274-1-ignat@cloudflare.com>
 <CALrw=nGhgRrhJ5mWWC6sV2WYWoijvD9WgFzMfOe6mHmqnza-Hw@mail.gmail.com>
 <D18XXJ373C2V.2M6AOMKD1B89W@kernel.org>
 <CALrw=nHGLN=dn3fbyAcXsBufw0tAWUT1PKVHDK5RZkHcdd3CUw@mail.gmail.com>
 <D19CUF0H9Q3S.3L5Y5S9553S5@kernel.org>
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In-Reply-To: <CALrw=nEZ07U9VhbGsnpchOYw1icUZCnuoHHXkJLzhFqSPe9_fQ@mail.gmail.com>

On Tue May 14, 2024 at 4:11 PM EEST, Ignat Korchagin wrote:
> For example, a cheap NAS box with no internal storage (disks connected
> externally via USB). We want:
>   * disks to be encrypted and decryptable only by this NAS box

So how this differs from LUKS2 style, which also systemd supports where
the encryption key is anchored to PCR's? If I took hard drive out of my
Linux box, I could not decrypt it in another machine because of this.

>   * if someone steals one of the disks - we don't want them to see it
> has encrypted data (no LUKS header)

So what happens when you reconnect?

> Additionally we may want to SSH into the NAS for configuration and we
> don't want the SSH server key to change after each boot (regardless if
> disks are connected or not).

Right, interesting use case. Begin before any technical jargon exactly
with a great example like this. Then it is easier to start to anchoring
stuff and not be misleaded.

BR, Jarkko