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
WARNING: multiple messages have this Message-ID (diff)
From: Satya Tangirala via Linux-f2fs-devel <linux-f2fs-devel@lists.sourceforge.net> To: Eric Biggers <ebiggers@kernel.org> Cc: "Theodore Y . Ts'o" <tytso@mit.edu>, linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-fscrypt@vger.kernel.org, Jaegeuk Kim <jaegeuk@kernel.org> Subject: Re: [f2fs-dev] [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 _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel
next prev parent reply other threads:[~2020-10-07 22:05 UTC|newest] Thread overview: 42+ 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 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 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 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 2020-10-05 7:36 ` [PATCH 2/3] fscrypt: Add metadata encryption support Satya Tangirala 2020-10-05 7:36 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 2020-10-07 20:52 ` Eric Biggers 2020-10-07 20:52 ` [f2fs-dev] " Eric Biggers 2020-10-07 23:28 ` Satya Tangirala 2020-10-07 23:28 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 2020-10-08 17:05 ` Eric Biggers 2020-10-08 17:05 ` [f2fs-dev] " Eric Biggers 2020-10-05 7:36 ` [PATCH 3/3] f2fs: " Satya Tangirala 2020-10-05 7:36 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 2020-10-05 10:19 ` kernel test robot 2020-10-05 10:19 ` kernel test robot 2020-10-07 21:20 ` Eric Biggers 2020-10-07 21:20 ` [f2fs-dev] " Eric Biggers 2020-10-08 0:31 ` Satya Tangirala 2020-10-08 0:31 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 2020-10-05 7:43 ` [PATCH 0/3] add support for metadata encryption to F2FS Satya Tangirala 2020-10-05 7:43 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 2020-10-07 21:00 ` Eric Biggers 2020-10-07 21:00 ` [f2fs-dev] " Eric Biggers 2020-10-07 22:05 ` Satya Tangirala [this message] 2020-10-07 22:05 ` Satya Tangirala via Linux-f2fs-devel 2020-10-08 17:01 ` Eric Biggers 2020-10-08 17:01 ` [f2fs-dev] " Eric Biggers 2020-10-10 9:53 ` Chao Yu 2020-10-10 9:53 ` [f2fs-dev] " Chao Yu 2020-12-17 15:44 ` Satya Tangirala 2020-12-17 15:44 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 2020-12-18 9:02 ` Chao Yu 2020-12-18 9:02 ` [f2fs-dev] " Chao Yu 2020-12-18 11:53 ` Satya Tangirala 2020-12-18 11:53 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 2020-12-22 11:47 ` Chao Yu 2020-12-22 11:47 ` [f2fs-dev] " Chao Yu 2020-12-24 10:13 ` Satya Tangirala 2020-12-24 10:13 ` [f2fs-dev] " Satya Tangirala via Linux-f2fs-devel 2020-12-25 9:31 ` Chao Yu 2020-12-25 9:31 ` [f2fs-dev] " Chao Yu
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