24 Jun, 2017

1 commit

• b7e7cf7a6   fscrypt: add support for AES-128-CBC ... Browse Code »

  fscrypt provides facilities to use different encryption algorithms which
  are selectable by userspace when setting the encryption policy. Currently,
  only AES-256-XTS for file contents and AES-256-CBC-CTS for file names are
  implemented. This is a clear case of kernel offers the mechanism and
  userspace selects a policy. Similar to what dm-crypt and ecryptfs have.

  This patch adds support for using AES-128-CBC for file contents and
  AES-128-CBC-CTS for file name encryption. To mitigate watermarking
  attacks, IVs are generated using the ESSIV algorithm. While AES-CBC is
  actually slightly less secure than AES-XTS from a security point of view,
  there is more widespread hardware support. Using AES-CBC gives us the
  acceptable performance while still providing a moderate level of security
  for persistent storage.

  Especially low-powered embedded devices with crypto accelerators such as
  CAAM or CESA often only support AES-CBC. Since using AES-CBC over AES-XTS
  is basically thought of a last resort, we use AES-128-CBC over AES-256-CBC
  since it has less encryption rounds and yields noticeable better
  performance starting from a file size of just a few kB.

  Signed-off-by: Daniel Walter
  [david@sigma-star.at: addressed review comments]
  Signed-off-by: David Gstir
  Reviewed-by: Eric Biggers
  Signed-off-by: Theodore Ts'o

  Daniel Walter

  2017-06-24 08:05:07 +0800  

02 Jan, 2017

1 commit

• 58ae74683   fscrypt: factor out bio specific functions ... Browse Code »

  That way we can get rid of the direct dependency on CONFIG_BLOCK.

  Fixes: d475a507457b ("ubifs: Add skeleton for fscrypto")
  Reported-by: Arnd Bergmann
  Reported-by: Randy Dunlap
  Reviewed-by: Eric Biggers
  Reviewed-by: Christoph Hellwig
  Reviewed-by: David Gstir
  Signed-off-by: Richard Weinberger
  Signed-off-by: Theodore Ts'o

  Richard Weinberger

  2017-01-02 05:18:49 +0800  

12 Dec, 2016

1 commit

• 804812357   fscrypto: remove unneeded Kconfig dependencies ... Browse Code »

  SHA256 and ENCRYPTED_KEYS are not needed. CTR shouldn't be needed
  either, but I left it for now because it was intentionally added by
  commit 71dea01ea2ed ("ext4 crypto: require CONFIG_CRYPTO_CTR if ext4
  encryption is enabled"). So it sounds like there may be a dependency
  problem elsewhere, which I have not been able to identify specifically,
  that must be solved before CTR can be removed.

  Signed-off-by: Eric Biggers
  Signed-off-by: Theodore Ts'o

  Eric Biggers

  2016-12-12 05:26:07 +0800  

18 Mar, 2016

1 commit

• 0b81d0779   fs crypto: move per-file encryption from f2fs tree to fs/crypto ... Browse Code »

  This patch adds the renamed functions moved from the f2fs crypto files.

  1. definitions for per-file encryption used by ext4 and f2fs.

  2. crypto.c for encrypt/decrypt functions
  a. IO preparation:
  - fscrypt_get_ctx / fscrypt_release_ctx
  b. before IOs:
  - fscrypt_encrypt_page
  - fscrypt_decrypt_page
  - fscrypt_zeroout_range
  c. after IOs:
  - fscrypt_decrypt_bio_pages
  - fscrypt_pullback_bio_page
  - fscrypt_restore_control_page

  3. policy.c supporting context management.
  a. For ioctls:
  - fscrypt_process_policy
  - fscrypt_get_policy
  b. For context permission
  - fscrypt_has_permitted_context
  - fscrypt_inherit_context

  4. keyinfo.c to handle permissions
  - fscrypt_get_encryption_info
  - fscrypt_free_encryption_info

  5. fname.c to support filename encryption
  a. general wrapper functions
  - fscrypt_fname_disk_to_usr
  - fscrypt_fname_usr_to_disk
  - fscrypt_setup_filename
  - fscrypt_free_filename

  b. specific filename handling functions
  - fscrypt_fname_alloc_buffer
  - fscrypt_fname_free_buffer

  6. Makefile and Kconfig

  Cc: Al Viro
  Signed-off-by: Michael Halcrow
  Signed-off-by: Ildar Muslukhov
  Signed-off-by: Uday Savagaonkar
  Signed-off-by: Theodore Ts'o
  Signed-off-by: Arnd Bergmann
  Signed-off-by: Jaegeuk Kim

  Jaegeuk Kim

  2016-03-18 12:19:33 +0800