From: Ignat Korchagin <ignat@cloudflare.com>
To: Jarkko Sakkinen <jarkko@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
Date: Tue, 14 May 2024 15:41:50 +0100 [thread overview]
Message-ID: <CALrw=nE_sV=1DnCx1eM8Sgno-di0yCaWHX467ZEf1Fddwg7_rA@mail.gmail.com> (raw)
In-Reply-To: <D19F74M6B8UC.2VEOOZHGOS87V@kernel.org>
On Tue, May 14, 2024 at 3:00 PM Jarkko Sakkinen <jarkko@kernel.org> wrote:
>
> 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.
It differs with the fact that the disk has a clearly identifiable
LUKS2 header, which tells an adversary that this is a disk with some
data that is encrypted. With derived keys and plain dm-crypt mode
there is no LUKS header, so it is not possible to tell if it is an
encrypted disk or a disk with just random data. Additionally, if I
accidentally wipe the sector with the LUKS2 header - all my data is
lost (because the data encryption key from the header is lost). With
derived keys I can always decrypt at least some data, if the disk is
available.
> > * 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?
We recover/derive the encryption key and unlock the disk again.
> > 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
next prev parent reply other threads:[~2024-05-14 14:42 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-03 22:16 [RFC PATCH 0/2] TPM derived keys Ignat Korchagin
2024-05-03 22:16 ` [RFC PATCH 1/2] tpm: add some algorithm and constant definitions from the TPM spec Ignat Korchagin
2024-05-14 22:51 ` Jarkko Sakkinen
2024-05-14 22:52 ` Jarkko Sakkinen
2024-05-03 22:16 ` [RFC PATCH 2/2] KEYS: implement derived keys Ignat Korchagin
2024-05-14 23:10 ` Jarkko Sakkinen
2024-05-14 23:44 ` Jarkko Sakkinen
2024-05-15 0:00 ` Jarkko Sakkinen
2024-05-15 6:44 ` Ignat Korchagin
2024-05-15 12:00 ` Jarkko Sakkinen
2024-05-15 12:03 ` Jarkko Sakkinen
2024-05-15 7:26 ` Ignat Korchagin
2024-05-04 0:21 ` [RFC PATCH 0/2] TPM " Jarkko Sakkinen
2024-05-04 13:55 ` Ben Boeckel
2024-05-04 14:51 ` Jarkko Sakkinen
2024-05-04 15:35 ` Jarkko Sakkinen
2024-05-13 17:09 ` Ignat Korchagin
2024-05-13 22:33 ` James Bottomley
2024-05-14 9:50 ` Ignat Korchagin
2024-05-14 14:11 ` James Bottomley
2024-05-14 14:54 ` Ignat Korchagin
2024-05-13 17:11 ` Ignat Korchagin
2024-05-14 0:28 ` Jarkko Sakkinen
2024-05-14 10:05 ` Ignat Korchagin
2024-05-14 12:09 ` Jarkko Sakkinen
2024-05-14 13:11 ` Ignat Korchagin
2024-05-14 14:00 ` Jarkko Sakkinen
2024-05-14 14:30 ` Jarkko Sakkinen
2024-05-14 15:21 ` Jarkko Sakkinen
2024-05-14 15:26 ` Jarkko Sakkinen
2024-05-14 15:30 ` Ignat Korchagin
2024-05-14 15:42 ` Jarkko Sakkinen
2024-05-14 16:08 ` Ignat Korchagin
2024-05-14 16:22 ` Jarkko Sakkinen
2024-05-14 14:41 ` Ignat Korchagin [this message]
2024-05-14 14:45 ` Jarkko Sakkinen
2024-05-14 15:30 ` James Bottomley
2024-05-14 15:38 ` Ignat Korchagin
2024-05-14 15:54 ` James Bottomley
2024-05-14 16:01 ` Ignat Korchagin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to='CALrw=nE_sV=1DnCx1eM8Sgno-di0yCaWHX467ZEf1Fddwg7_rA@mail.gmail.com' \
--to=ignat@cloudflare.com \
--cc=James.Bottomley@hansenpartnership.com \
--cc=dhowells@redhat.com \
--cc=jarkko@kernel.org \
--cc=jmorris@namei.org \
--cc=kernel-team@cloudflare.com \
--cc=keyrings@vger.kernel.org \
--cc=linux-integrity@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=paul@paul-moore.com \
--cc=serge@hallyn.com \
--cc=zohar@linux.ibm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).