Re: [PATCH 15/26] ubifs: Implement encrypt/decrypt for all IO

From	Michael Halcrow <mhalcrow@google.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 15/26] ubifs: Implement encrypt/decrypt for all IO
Date	2016-10-21 20:00 +0200
Message-ID	<suMgT-so-31@gated-at.bofh.it> (permalink)
References	<suHqN-5zP-5@gated-at.bofh.it> <suHAu-5DG-5@gated-at.bofh.it> <suLE6-dO-5@gated-at.bofh.it> <suLNM-hj-31@gated-at.bofh.it>
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On Fri, Oct 21, 2016 at 07:21:04PM +0200, Richard Weinberger wrote:
> On 21.10.2016 19:14, Michael Halcrow wrote:
> > Compress-before-encrypt is a hazard.
> > 
> > http://www.iacr.org/cryptodb/archive/2002/FSE/3091/3091.pdf
> 
> I'm fully aware of that. But as usual it depends on the use case.
> Compression is optional in UBIFS, paranoid users can disable it
> when encryption is enabled.

It's not the paranoid users I'm concerned about.  It's those building
systems with complexity and nuance on top of UBIFS who aren't paranoid
enough.

I suggest disabling compression by default when encryption is enabled,
unless the user explicitly enables both.

> 
> Thanks,
> //richard

Thread

[PATCH 00/26] UBIFS File Encryption Richard Weinberger <richard@nod.at> - 2016-10-21 14:50 +0200
  [PATCH 26/26] ubifs: Raise write version to 5 Richard Weinberger <richard@nod.at> - 2016-10-21 14:50 +0200
    Re: [PATCH 26/26] ubifs: Raise write version to 5 Michael Halcrow <mhalcrow@google.com> - 2016-10-21 19:40 +0200
      Re: [PATCH 26/26] ubifs: Raise write version to 5 Theodore Ts'o <tytso@mit.edu> - 2016-10-21 19:50 +0200
        Re: [PATCH 26/26] ubifs: Raise write version to 5 Eric Biggers <ebiggers@google.com> - 2016-10-21 20:20 +0200
          Re: [PATCH 26/26] ubifs: Raise write version to 5 Theodore Ts'o <tytso@mit.edu> - 2016-10-22 00:40 +0200
        Re: [PATCH 26/26] ubifs: Raise write version to 5 Richard Weinberger <richard@nod.at> - 2016-10-24 09:10 +0200
  [PATCH 05/26] ubifs: Define UBIFS crypto context xattr Richard Weinberger <richard@nod.at> - 2016-10-21 14:50 +0200
  [PATCH 10/26] ubifs: Enforce crypto policy in ->link and ->rename Richard Weinberger <richard@nod.at> - 2016-10-21 14:50 +0200
  [PATCH 15/26] ubifs: Implement encrypt/decrypt for all IO Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
    Re: [PATCH 15/26] ubifs: Implement encrypt/decrypt for all IO Michael Halcrow <mhalcrow@google.com> - 2016-10-21 19:20 +0200
      Re: [PATCH 15/26] ubifs: Implement encrypt/decrypt for all IO Richard Weinberger <richard@nod.at> - 2016-10-21 19:30 +0200
        Re: [PATCH 15/26] ubifs: Implement encrypt/decrypt for all IO Michael Halcrow <mhalcrow@google.com> - 2016-10-21 20:00 +0200
          Re: [PATCH 15/26] ubifs: Implement encrypt/decrypt for all IO Richard Weinberger <richard@nod.at> - 2016-10-21 20:30 +0200
    Re: [PATCH 15/26] ubifs: Implement encrypt/decrypt for all IO Eric Biggers <ebiggers@google.com> - 2016-10-21 20:30 +0200
      Re: [PATCH 15/26] ubifs: Implement encrypt/decrypt for all IO Richard Weinberger <richard@nod.at> - 2016-10-24 09:10 +0200
  [PATCH 07/26] ubifs: Massage ubifs_listxattr() for encryption context Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
  [PATCH 13/26] ubifs: Enforce crypto policy in mmap Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
  [PATCH 11/26] ubifs: Preload crypto context in ->lookup() Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
  [PATCH 21/26] ubifs: Rename tnc_read_node_nm Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
  [PATCH 12/26] ubifs: Massage assert in ubifs_xattr_set() wrt. fscrypto Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
  [PATCH 02/26] fscrypto: Constify struct inode pointer Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
    Re: [PATCH 02/26] fscrypto: Constify struct inode pointer Theodore Ts'o <tytso@mit.edu> - 2016-10-21 17:00 +0200
      Re: [PATCH 02/26] fscrypto: Constify struct inode pointer Richard Weinberger <richard@nod.at> - 2016-10-21 17:20 +0200
  [PATCH 22/26] ubifs: Add full hash lookup support Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
  [PATCH 24/26] ubifs: Implement UBIFS_FLG_DOUBLE_HASH Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
  [PATCH 25/26] ubifs: Implement UBIFS_FLG_ENCRYPTION Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
    Re: [PATCH 25/26] ubifs: Implement UBIFS_FLG_ENCRYPTION Eric Biggers <ebiggers@google.com> - 2016-10-21 20:40 +0200
      Re: [PATCH 25/26] ubifs: Implement UBIFS_FLG_ENCRYPTION Richard Weinberger <richard@nod.at> - 2016-10-24 09:00 +0200
        Re: [PATCH 25/26] ubifs: Implement UBIFS_FLG_ENCRYPTION Theodore Ts'o <tytso@mit.edu> - 2016-10-24 15:50 +0200
  [PATCH 17/26] ubifs: Make r5 hash binary string aware Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
  [PATCH 20/26] ubifs: Add support for encrypted symlinks Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
    Re: [PATCH 20/26] ubifs: Add support for encrypted symlinks Eric Biggers <ebiggers@google.com> - 2016-10-21 20:50 +0200
      Re: [PATCH 20/26] ubifs: Add support for encrypted symlinks Richard Weinberger <richard@nod.at> - 2016-10-24 09:00 +0200
  [PATCH 23/26] ubifs: Use a random number for cookies Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
  [PATCH 08/26] ubifs: Implement directory open operation Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
  [PATCH 14/26] ubifs: Introduce new data node field, compr_size Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
  [PATCH 16/26] ubifs: Relax checks in ubifs_validate_entry() Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
  [PATCH 18/26] ubifs: Constify struct inode pointer in ubifs_crypt_is_encrypted() Richard Weinberger <richard@nod.at> - 2016-10-21 15:00 +0200
  [PATCH 06/26] ubifs: Add skeleton for fscrypto Richard Weinberger <richard@nod.at> - 2016-10-21 15:10 +0200
  Re: [PATCH 01/26] fscrypto: Add buffer operations Christoph Hellwig <hch@infradead.org> - 2016-10-21 15:10 +0200
    Re: [PATCH 01/26] fscrypto: Add buffer operations Richard Weinberger <richard@nod.at> - 2016-10-21 15:20 +0200
      Re: [PATCH 01/26] fscrypto: Add buffer operations Christoph Hellwig <hch@infradead.org> - 2016-10-21 15:30 +0200
        Re: [PATCH 01/26] fscrypto: Add buffer operations Theodore Ts'o <tytso@mit.edu> - 2016-10-21 17:20 +0200
        Re: [PATCH 01/26] fscrypto: Add buffer operations Richard Weinberger <richard@nod.at> - 2016-10-24 09:10 +0200
  [PATCH 09/26] ubifs: Implement file open operation Richard Weinberger <richard@nod.at> - 2016-10-21 15:10 +0200
  [PATCH 03/26] ubifs: Export ubifs_check_dir_empty() Richard Weinberger <richard@nod.at> - 2016-10-21 15:10 +0200
  [PATCH 04/26] ubifs: Export xattr get and set functions Richard Weinberger <richard@nod.at> - 2016-10-21 15:10 +0200
  [PATCH 01/26] fscrypto: Add buffer operations Richard Weinberger <richard@nod.at> - 2016-10-21 15:10 +0200

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