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From: David Sterba <dsterba@suse.cz>
To: Johannes Thumshirn <jthumshirn@suse.de>
Cc: David Sterba <dsterba@suse.com>,
	Linux BTRFS Mailinglist <linux-btrfs@vger.kernel.org>
Subject: Re: [PATCH 00/17] Add support for SHA-256 checksums
Date: Wed, 15 May 2019 19:27:21 +0200	[thread overview]
Message-ID: <20190515172720.GX3138@twin.jikos.cz> (raw)
In-Reply-To: <20190510111547.15310-1-jthumshirn@suse.de>

On Fri, May 10, 2019 at 01:15:30PM +0200, Johannes Thumshirn wrote:
> This patchset add support for adding new checksum types in BTRFS.
> 
> Currently BTRFS only supports CRC32C as data and metadata checksum, which is
> good if you only want to detect errors due to data corruption in hardware.
> 
> But CRC32C isn't able cover other use-cases like de-duplication or
> cryptographically save data integrity guarantees.
> 
> The following properties made SHA-256 interesting for these use-cases:
> - Still considered cryptographically sound
> - Reasonably well understood by the security industry
> - Result fits into the 32Byte/256Bit we have for the checksum in the on-disk
>   format
> - Small enough collision space to make it feasible for data de-duplication
> - Fast enough to calculate and offloadable to crypto hardware via the kernel's
>   crypto_shash framework.
> 
> The patchset also provides mechanisms for plumbing in different hash
> algorithms relatively easy.

Once the code is ready for more checksum algos, we'll pick candidates
and my idea is to select 1 fast (not necessarily strong, but better
than crc32c) and 1 strong (but slow, and sha256 is the candidate at the
moment).

The discussion from 2014 on that topic brought a lot of useful
information, though some algos have could have evolved since.

https://lore.kernel.org/linux-btrfs/1416806586-18050-1-git-send-email-bo.li.liu@oracle.com/

In about 5 years timeframe we can revisit the algos and potentially add
more, so I hope we'll be able to agree to add just 2 in this round.

The minimum selection criteria for a digest algorithm:

- is provided by linux kernel crypto subsystem
- has a license that will allow to use it in bootloader code (grub at
  lest)
- the implementation is available for btrfs-progs either as some small
  library or can be used directly as a .c file

  parent reply	other threads:[~2019-05-15 17:26 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-10 11:15 [PATCH 00/17] Add support for SHA-256 checksums Johannes Thumshirn
2019-05-10 11:15 ` [PATCH 01/17] btrfs: use btrfs_csum_data() instead of directly calling crc32c Johannes Thumshirn
2019-05-10 16:16   ` Nikolay Borisov
2019-05-10 11:15 ` [PATCH 02/17] btrfs: resurrect btrfs_crc32c() Johannes Thumshirn
2019-05-10 16:16   ` Nikolay Borisov
2019-05-10 11:15 ` [PATCH 03/17] btrfs: use btrfs_crc32c() instead of btrfs_extref_hash() Johannes Thumshirn
2019-05-10 13:03   ` Nikolay Borisov
2019-05-10 11:15 ` [PATCH 04/17] btrfs: use btrfs_crc32c() instead of btrfs_name_hash() Johannes Thumshirn
2019-05-10 12:56   ` Chris Mason
2019-05-13  7:04     ` Johannes Thumshirn
2019-05-10 11:15 ` [PATCH 05/17] btrfs: don't assume ordered sums to be 4 bytes Johannes Thumshirn
2019-05-10 13:25   ` Nikolay Borisov
2019-05-10 13:27     ` Nikolay Borisov
2019-05-13  7:06       ` Johannes Thumshirn
2019-05-10 11:15 ` [PATCH 06/17] btrfs: dont assume compressed_bio " Johannes Thumshirn
2019-05-10 11:15 ` [PATCH 07/17] btrfs: use btrfs_crc32c{,_final}() in for free space cache Johannes Thumshirn
2019-05-10 13:27   ` Nikolay Borisov
2019-05-10 11:15 ` [PATCH 08/17] btrfs: format checksums according to type for printing Johannes Thumshirn
2019-05-10 13:28   ` Nikolay Borisov
2019-05-10 11:15 ` [PATCH 09/17] btrfs: add common checksum type validation Johannes Thumshirn
2019-05-10 13:37   ` Nikolay Borisov
2019-05-10 11:15 ` [PATCH 10/17] btrfs: check for supported superblock checksum type before checksum validation Johannes Thumshirn
2019-05-10 13:37   ` Nikolay Borisov
2019-05-10 11:15 ` [PATCH 11/17] btrfs: Simplify btrfs_check_super_csum() and get rid of size assumptions Johannes Thumshirn
2019-05-10 13:41   ` Nikolay Borisov
2019-05-10 11:15 ` [PATCH 12/17] btrfs: add boilerplate code for directly including the crypto framework Johannes Thumshirn
2019-05-10 16:28   ` Nikolay Borisov
2019-05-10 11:15 ` [PATCH 13/17] btrfs: pass in an fs_info to btrfs_csum_{data,final}() Johannes Thumshirn
2019-05-10 11:15 ` [PATCH 14/17] btrfs: directly call into crypto framework for checsumming Johannes Thumshirn
2019-05-10 13:45   ` Chris Mason
2019-05-10 13:54     ` Chris Mason
2019-05-13  7:17       ` Johannes Thumshirn
2019-05-13 13:55         ` Chris Mason
2019-05-14 12:46     ` Johannes Thumshirn
2019-05-13 13:00   ` David Sterba
2019-05-13 13:01     ` Johannes Thumshirn
2019-05-13 14:30       ` David Sterba
2019-05-10 11:15 ` [PATCH 15/17] btrfs: remove assumption about csum type form btrfs_csum_{data,final}() Johannes Thumshirn
2019-05-13 12:56   ` David Sterba
2019-05-10 11:15 ` [PATCH 16/17] btrfs: remove assumption about csum type form btrfs_print_data_csum_error() Johannes Thumshirn
2019-05-10 11:15 ` [PATCH 17/17] btrfs: add sha256 as another checksum algorithm Johannes Thumshirn
2019-05-10 12:30   ` Nikolay Borisov
2019-05-13  7:11     ` Johannes Thumshirn
2019-05-13 12:54       ` David Sterba
2019-05-13 12:55         ` Johannes Thumshirn
2019-05-15  1:45         ` Jeff Mahoney
2019-05-13 12:55     ` David Sterba
2019-05-13 12:58       ` Johannes Thumshirn
2019-05-15 17:27 ` David Sterba [this message]
2019-05-16  6:30   ` [PATCH 00/17] Add support for SHA-256 checksums Paul Jones
2019-05-16  8:16     ` Nikolay Borisov
2019-05-16  8:20       ` Johannes Thumshirn
2019-05-17 18:36   ` Diego Calleja
2019-05-17 19:07     ` Johannes Thumshirn
2019-05-18  0:38       ` Adam Borowski
2019-05-20  7:47         ` Johannes Thumshirn
2019-05-20 11:34           ` Austin S. Hemmelgarn
2019-05-20 11:57             ` Johannes Thumshirn
2019-05-20 11:42     ` Austin S. Hemmelgarn
2019-05-30 12:21     ` David Sterba

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