From: Satya Tangirala <satyat@google.com>
To: Eric Biggers <ebiggers@kernel.org>
Cc: "Theodore Y . Ts'o" <tytso@mit.edu>,
Jaegeuk Kim <jaegeuk@kernel.org>, Chao Yu <chao@kernel.org>,
linux-kernel@vger.kernel.org, linux-fscrypt@vger.kernel.org,
linux-f2fs-devel@lists.sourceforge.net
Subject: Re: [PATCH 0/3] add support for metadata encryption to F2FS
Date: Wed, 7 Oct 2020 22:05:00 +0000 [thread overview]
Message-ID: <20201007220500.GA2544297@google.com> (raw)
In-Reply-To: <20201007210040.GB1530638@gmail.com>
On Wed, Oct 07, 2020 at 02:00:40PM -0700, Eric Biggers wrote:
> On Mon, Oct 05, 2020 at 07:36:03AM +0000, Satya Tangirala wrote:
> > This patch series adds support for metadata encryption to F2FS using
> > blk-crypto.
>
> This patch series needs more explanation about what "metadata encryption" is,
> why people will want to use it (as opposed to either not using it, or using
> fscrypt + dm-crypt instead), and why this is the best implementation of it.
>
Sure, I'll add that in the next version
> > Patch 2 introduces some functions to fscrypt that help filesystems perform
> > metadata encryption. Any filesystem that wants to use metadata encryption
> > can call fscrypt_setup_metadata_encryption() with the super_block of the
> > filesystem, the encryption algorithm and the descriptor of the encryption
> > key. The descriptor is looked up in the logon keyring of the current
> > session with "fscrypt:" as the prefix of the descriptor.
>
> I notice this is missing the step I suggested to include the metadata encryption
> key in the HKDF application-specific info string when deriving subkeys from the
> fscrypt master keys.
>
> The same effect could also be achieved by adding an additional level to the key
> hierarchy: each HKDF key would be derived from a fscrypt master key and the
> metadata encryption key.
>
> We need one of those, to guarantee that the file contents encryption is at least
> as strong as the "metadata encryption".
>
Yes - I didn't get around to that in the first version, but I'll add
that too in the next version. I was going to go with the first approach
before I saw your comment - is there one method you'd recommend going
with over the other?
> - Eric
next prev parent reply other threads:[~2020-10-07 22:05 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-05 7:36 [PATCH 0/3] add support for metadata encryption to F2FS Satya Tangirala
2020-10-05 7:36 ` [PATCH 1/3] fscrypt, f2fs: replace fscrypt_get_devices with fscrypt_get_device Satya Tangirala
2020-10-05 7:36 ` [PATCH 2/3] fscrypt: Add metadata encryption support Satya Tangirala
2020-10-07 20:52 ` Eric Biggers
2020-10-07 23:28 ` Satya Tangirala
2020-10-08 17:05 ` Eric Biggers
2020-10-05 7:36 ` [PATCH 3/3] f2fs: " Satya Tangirala
2020-10-05 10:19 ` kernel test robot
2020-10-07 21:20 ` Eric Biggers
2020-10-08 0:31 ` Satya Tangirala
2020-10-05 7:43 ` [PATCH 0/3] add support for metadata encryption to F2FS Satya Tangirala
2020-10-07 21:00 ` Eric Biggers
2020-10-07 22:05 ` Satya Tangirala [this message]
2020-10-08 17:01 ` Eric Biggers
2020-10-10 9:53 ` Chao Yu
2020-12-17 15:44 ` Satya Tangirala
2020-12-18 9:02 ` Chao Yu
2020-12-18 11:53 ` Satya Tangirala
2020-12-22 11:47 ` Chao Yu
2020-12-24 10:13 ` Satya Tangirala
2020-12-25 9:31 ` Chao Yu
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