linux.git/drivers/md/dm-crypt.c, branch v5.8

dm crypt: avoid truncating the logical block size

2020-06-05T18:59:59+00:00

queue_limits::logical_block_size got changed from unsigned short to
unsigned int, but it was forgotten to update crypt_io_hints() to use the
new type.  Fix it.

Fixes: ad6bf88a6c19 ("block: fix an integer overflow in logical block size")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers 
Reviewed-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer

dm: replace zero-length array with flexible-array

2020-05-20T21:09:44+00:00

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
        int stuff;
        struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

sizeof(flexible-array-member) triggers a warning because flexible array
members have incomplete type[1]. There are some instances of code in
which the sizeof operator is being incorrectly/erroneously applied to
zero-length arrays and the result is zero. Such instances may be hiding
some bugs. So, this work (flexible-array member conversions) will also
help to get completely rid of those sorts of issues.

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva 
Signed-off-by: Mike Snitzer

dm crypt: support using encrypted keys

2020-05-15T14:29:34+00:00

Allow one to use "encrypted" in addition to "user" and "logon" key
types for device encryption.

Signed-off-by: Dmitry Baryshkov 
Signed-off-by: Mike Snitzer

dm crypt: use crypt_integrity_aead() helper

2020-03-24T15:17:33+00:00

Replace test_bit(CRYPT_MODE_INTEGRITY_AEAD, XXX) with
crypt_integrity_aead().

Signed-off-by: Yang Yingliang 
Signed-off-by: Mike Snitzer

dm crypt: fix benbi IV constructor crash if used in authenticated mode

2020-01-15T01:22:47+00:00

If benbi IV is used in AEAD construction, for example:
  cryptsetup luksFormat  --cipher twofish-xts-benbi --key-size 512 --integrity=hmac-sha256
the constructor uses wrong skcipher function and crashes:

 BUG: kernel NULL pointer dereference, address: 00000014
 ...
 EIP: crypt_iv_benbi_ctr+0x15/0x70 [dm_crypt]
 Call Trace:
  ? crypt_subkey_size+0x20/0x20 [dm_crypt]
  crypt_ctr+0x567/0xfc0 [dm_crypt]
  dm_table_add_target+0x15f/0x340 [dm_mod]

Fix this by properly using crypt_aead_blocksize() in this case.

Fixes: ef43aa38063a6 ("dm crypt: add cryptographic data integrity protection (authenticated encryption)")
Cc: stable@vger.kernel.org # v4.12+
Link: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=941051
Reported-by: Jerad Simpson 
Signed-off-by: Milan Broz 
Signed-off-by: Mike Snitzer

dm crypt: Implement Elephant diffuser for Bitlocker compatibility

2020-01-15T01:22:46+00:00

Add experimental support for BitLocker encryption with CBC mode and
additional Elephant diffuser.

The mode was used in older Windows systems and it is provided mainly
for compatibility reasons. The userspace support to activate these
devices is being added to cryptsetup utility.

Read-write activation of such a device is very simple, for example:
  echo  | cryptsetup bitlkOpen bitlk_image.img test

The Elephant diffuser uses two rotations in opposite direction for
data (Diffuser A and B) and also XOR operation with Sector key over
the sector data; Sector key is derived from additional key data. The
original public documentation is available here:
  http://download.microsoft.com/download/0/2/3/0238acaf-d3bf-4a6d-b3d6-0a0be4bbb36e/bitlockercipher200608.pdf

The dm-crypt implementation is embedded to "elephant" IV (similar to
tcw IV construction).

Because we cannot modify original bio data for write (before
encryption), an additional internal flag to pre-process data is
added.

Signed-off-by: Milan Broz 
Reviewed-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer

dm crypt: fix GFP flags passed to skcipher_request_alloc()

2020-01-07T17:07:32+00:00

GFP_KERNEL is not supposed to be or'd with GFP_NOFS (the result is
equivalent to GFP_KERNEL). Also, we use GFP_NOIO instead of GFP_NOFS
because we don't want any I/O being submitted in the direct reclaim
path.

Fixes: 39d13a1ac41d ("dm crypt: reuse eboiv skcipher for IV generation")
Cc: stable@vger.kernel.org # v5.4+
Signed-off-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer

Revert "dm crypt: use WQ_HIGHPRI for the IO and crypt workqueues"

2019-11-20T22:27:39+00:00

This reverts commit a1b89132dc4f61071bdeaab92ea958e0953380a1.

Revert required hand-patching due to subsequent changes that were
applied since commit a1b89132dc4f61071bdeaab92ea958e0953380a1.

Requires: ed0302e83098d ("dm crypt: make workqueue names device-specific")
Cc: stable@vger.kernel.org
Bug: https://bugzilla.kernel.org/show_bug.cgi?id=199857
Reported-by: Vito Caputo 
Signed-off-by: Mike Snitzer

dm crypt: omit parsing of the encapsulated cipher

2019-09-03T20:46:16+00:00

Only the ESSIV IV generation mode used to use cc->cipher so it could
instantiate the bare cipher used to encrypt the IV. However, this is
now taken care of by the ESSIV template, and so no users of cc->cipher
remain. So remove it altogether.

Signed-off-by: Ard Biesheuvel 
Tested-by: Milan Broz 
Signed-off-by: Mike Snitzer

dm crypt: switch to ESSIV crypto API template

2019-09-03T20:45:54+00:00

Replace the explicit ESSIV handling in the dm-crypt driver with calls
into the crypto API, which now possesses the capability to perform
this processing within the crypto subsystem.

Note that we reorder the AEAD cipher_api string parsing with the TFM
instantiation: this is needed because cipher_api is mangled by the
ESSIV handling, and throws off the parsing of "authenc(" otherwise.

Signed-off-by: Ard Biesheuvel 
Tested-by: Milan Broz 
Signed-off-by: Mike Snitzer