dm crypt: fix parsing of extended IV arguments
authorMilan Broz <gmazyland@gmail.com>
Wed, 9 Jan 2019 10:57:14 +0000 (11:57 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 31 Jan 2019 07:13:45 +0000 (08:13 +0100)
commit06fc0dbec672bc118b24c8ce92314a5931a0796f
tree8225bfc8848bd7e1a64d9a6bc1cb99e6e5350451
parent294710ddfc480aee277325cee8b54afa0c514e43
dm crypt: fix parsing of extended IV arguments

commit 1856b9f7bcc8e9bdcccc360aabb56fbd4dd6c565 upstream.

The dm-crypt cipher specification in a mapping table is defined as:
  cipher[:keycount]-chainmode-ivmode[:ivopts]
or (new crypt API format):
  capi:cipher_api_spec-ivmode[:ivopts]

For ESSIV, the parameter includes hash specification, for example:
aes-cbc-essiv:sha256

The implementation expected that additional IV option to never include
another dash '-' character.

But, with SHA3, there are names like sha3-256; so the mapping table
parser fails:

dmsetup create test --table "0 8 crypt aes-cbc-essiv:sha3-256 9c1185a5c5e9fc54612808977ee8f5b9e 0 /dev/sdb 0"
  or (new crypt API format)
dmsetup create test --table "0 8 crypt capi:cbc(aes)-essiv:sha3-256 9c1185a5c5e9fc54612808977ee8f5b9e 0 /dev/sdb 0"

  device-mapper: crypt: Ignoring unexpected additional cipher options
  device-mapper: table: 253:0: crypt: Error creating IV
  device-mapper: ioctl: error adding target to table

Fix the dm-crypt constructor to ignore additional dash in IV options and
also remove a bogus warning (that is ignored anyway).

Cc: stable@vger.kernel.org # 4.12+
Signed-off-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/md/dm-crypt.c