linux.git/crypto/skcipher.c, branch v4.11

crypto: Replaced gcc specific attributes with macros from compiler.h

2017-01-12T16:24:39+00:00

Continuing from this commit: 52f5684c8e1e
("kernel: use macros from compiler.h instead of __attribute__((...))")

I submitted 4 total patches. They are part of task I've taken up to
increase compiler portability in the kernel. I've cleaned up the
subsystems under /kernel /mm /block and /security, this patch targets
/crypto.

There is  which provides macros for various gcc specific
constructs. Eg: __weak for __attribute__((weak)). I've cleaned all
instances of gcc specific attributes with the right macros for the crypto
subsystem.

I had to make one additional change into compiler-gcc.h for the case when
one wants to use this: __attribute__((aligned) and not specify an alignment
factor. From the gcc docs, this will result in the largest alignment for
that data type on the target machine so I've named the macro
__aligned_largest. Please advise if another name is more appropriate.

Signed-off-by: Gideon Israel Dsouza 
Signed-off-by: Herbert Xu

crypto: skcipher - introduce walksize attribute for SIMD algos

2016-12-30T11:52:47+00:00

In some cases, SIMD algorithms can only perform optimally when
allowed to operate on multiple input blocks in parallel. This is
especially true for bit slicing algorithms, which typically take
the same amount of time processing a single block or 8 blocks in
parallel. However, other SIMD algorithms may benefit as well from
bigger strides.

So add a walksize attribute to the skcipher algorithm definition, and
wire it up to the skcipher walk API. To avoid confusion between the
skcipher and AEAD attributes, rename the skcipher_walk chunksize
attribute to 'stride', and set it from the walksize (in the skcipher
case) or from the chunksize (in the AEAD case).

Signed-off-by: Ard Biesheuvel 
Signed-off-by: Herbert Xu

crypto: skcipher - fix crash in virtual walk

2016-12-14T10:33:14+00:00

The new skcipher walk API may crash in the following way. (Interestingly,
the tcrypt boot time tests seem unaffected, while an explicit test using
the module triggers it)

  Unable to handle kernel NULL pointer dereference at virtual address 00000000
  ...
  [] __memcpy+0x84/0x180
  [] skcipher_walk_done+0x328/0x340
  [] ctr_encrypt+0x84/0x100
  [] simd_skcipher_encrypt+0x88/0x98
  [] crypto_rfc3686_crypt+0x8c/0x98
  [] test_skcipher_speed+0x518/0x820 [tcrypt]
  [] do_test+0x1408/0x3b70 [tcrypt]
  [] tcrypt_mod_init+0x50/0x1000 [tcrypt]
  [] do_one_initcall+0x44/0x138
  [] do_init_module+0x68/0x1e0
  [] load_module+0x1fd0/0x2458
  [] SyS_finit_module+0xe0/0xf0
  [] el0_svc_naked+0x24/0x28

This is due to the fact that skcipher_done_slow() may be entered with
walk->buffer unset. Since skcipher_walk_done() already deals with the
case where walk->buffer == walk->page, it appears to be the intention
that walk->buffer point to walk->page after skcipher_next_slow(), so
ensure that is the case.

Signed-off-by: Ard Biesheuvel 
Signed-off-by: Herbert Xu

crypto: skcipher - Add separate walker for AEAD decryption

2016-12-01T13:06:17+00:00

The AEAD decrypt interface includes the authentication tag in
req->cryptlen.  Therefore we need to exlucde that when doing
a walk over it.

This patch adds separate walker functions for AEAD encryption
and decryption.

Signed-off-by: Herbert Xu 
Reviewed-by: Ard Biesheuvel

crypto: skcipher - fix crash in skcipher_walk_aead()

2016-11-30T12:01:43+00:00

The new skcipher_walk_aead() may crash in the following way due to
the walk flag SKCIPHER_WALK_PHYS not being cleared at the start of the
walk:

Unable to handle kernel NULL pointer dereference at virtual address 00000001
[..]
Internal error: Oops: 96000044 [#1] PREEMPT SMP
[..]
PC is at skcipher_walk_next+0x208/0x450
LR is at skcipher_walk_next+0x1e4/0x450
pc : [] lr : [] pstate: 40000045
sp : ffffb925fa517940
[...]
[] skcipher_walk_next+0x208/0x450
[] skcipher_walk_first+0x54/0x148
[] skcipher_walk_aead+0xd4/0x108
[] ccm_encrypt+0x68/0x158

So clear the flag at the appropriate time.

Signed-off-by: Ard Biesheuvel 
Signed-off-by: Herbert Xu

crypto: skcipher - Add skcipher walk interface

2016-11-28T13:23:17+00:00

This patch adds the skcipher walk interface which replaces both
blkcipher walk and ablkcipher walk.  Just like blkcipher walk it
can also be used for AEAD algorithms.

Signed-off-by: Herbert Xu

crypto: skcipher - Remove top-level givcipher interface

2016-07-18T09:35:46+00:00

This patch removes the old crypto_grab_skcipher helper and replaces
it with crypto_grab_skcipher2.

As this is the final entry point into givcipher this patch also
removes all traces of the top-level givcipher interface, including
all implicit IV generators such as chainiv.

The bottom-level givcipher interface remains until the drivers
using it are converted.

Signed-off-by: Herbert Xu

crypto: skcipher - Add low-level skcipher interface

2016-07-18T09:35:36+00:00

This patch allows skcipher algorithms and instances to be created
and registered with the crypto API.  They are accessible through
the top-level skcipher interface, along with ablkcipher/blkcipher
algorithms and instances.

This patch also introduces a new parameter called chunk size
which is meant for ciphers such as CTR and CTS which ostensibly
can handle arbitrary lengths, but still behave like block ciphers
in that you can only process a partial block at the very end.

For these ciphers the block size will continue to be set to 1
as it is now while the chunk size will be set to the underlying
block size.

Signed-off-by: Herbert Xu

crypto: skcipher - Add default key size helper

2016-01-25T14:42:11+00:00

While converting ecryptfs over to skcipher I found that it needs
to pick a default key size if one isn't given.  Rather than having
it poke into the guts of the algorithm to get max_keysize, let's
provide a helper that is meant to give a sane default (just in
case we ever get an algorithm that has no maximum key size).

Signed-off-by: Herbert Xu

crypto: skcipher - Add crypto_skcipher_has_setkey

2016-01-18T10:16:12+00:00

This patch adds a way for skcipher users to determine whether a key
is required by a transform.

Cc: stable@vger.kernel.org
Signed-off-by: Herbert Xu