Commit Graph

19 Commits

Author SHA1 Message Date
Stephan Müller 43490e8046 crypto: drbg - in-place cipher operation for CTR
The cipher implementations of the kernel crypto API favor in-place
cipher operations. Thus, switch the CTR cipher operation in the DRBG to
perform in-place operations. This is implemented by using the output
buffer as input buffer and zeroizing it before the cipher operation to
implement a CTR encryption of a NULL buffer.

The speed improvement is quite visibile with the following comparison
using the LRNG implementation.

Without the patch set:

      16 bytes|           12.267661 MB/s|    61338304 bytes |  5000000213 ns
      32 bytes|           23.603770 MB/s|   118018848 bytes |  5000000073 ns
      64 bytes|           46.732262 MB/s|   233661312 bytes |  5000000241 ns
     128 bytes|           90.038042 MB/s|   450190208 bytes |  5000000244 ns
     256 bytes|          160.399616 MB/s|   801998080 bytes |  5000000393 ns
     512 bytes|          259.878400 MB/s|  1299392000 bytes |  5000001675 ns
    1024 bytes|          386.050662 MB/s|  1930253312 bytes |  5000001661 ns
    2048 bytes|          493.641728 MB/s|  2468208640 bytes |  5000001598 ns
    4096 bytes|          581.835981 MB/s|  2909179904 bytes |  5000003426 ns

With the patch set:

      16 bytes |         17.051142 MB/s |     85255712 bytes |  5000000854 ns
      32 bytes |         32.695898 MB/s |    163479488 bytes |  5000000544 ns
      64 bytes |         64.490739 MB/s |    322453696 bytes |  5000000954 ns
     128 bytes |        123.285043 MB/s |    616425216 bytes |  5000000201 ns
     256 bytes |        233.434573 MB/s |   1167172864 bytes |  5000000573 ns
     512 bytes |        384.405197 MB/s |   1922025984 bytes |  5000000671 ns
    1024 bytes |        566.313370 MB/s |   2831566848 bytes |  5000001080 ns
    2048 bytes |        744.518042 MB/s |   3722590208 bytes |  5000000926 ns
    4096 bytes |        867.501670 MB/s |   4337508352 bytes |  5000002181 ns

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-08-03 18:05:48 +08:00
Stephan Mueller cf862cbc83 crypto: drbg - eliminate constant reinitialization of SGL
The CTR DRBG requires two SGLs pointing to input/output buffers for the
CTR AES operation. The used SGLs always have only one entry. Thus, the
SGL can be initialized during allocation time, preventing a
re-initialization of the SGLs during each call.

The performance is increased by about 1 to 3 percent depending on the
size of the requested buffer size.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2018-07-20 13:51:21 +08:00
Gilad Ben-Yossef 85a2dea4bd crypto: drbg - move to generic async completion
DRBG is starting an async. crypto op and waiting for it complete.
Move it over to generic code doing the same.

The code now also passes CRYPTO_TFM_REQ_MAY_SLEEP flag indicating
crypto request memory allocation may use GFP_KERNEL which should
be perfectly fine as the code is obviously sleeping for the
completion of the request any way.

Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2017-11-03 22:11:19 +08:00
Stephan Mueller 5102981212 crypto: drbg - prevent invalid SG mappings
When using SGs, only heap memory (memory that is valid as per
virt_addr_valid) is allowed to be referenced. The CTR DRBG used to
reference the caller-provided memory directly in an SG. In case the
caller provided stack memory pointers, the SG mapping is not considered
to be valid. In some cases, this would even cause a paging fault.

The change adds a new scratch buffer that is used unconditionally to
catch the cases where the caller-provided buffer is not suitable for
use in an SG. The crypto operation of the CTR DRBG produces its output
with that scratch buffer and finally copies the content of the
scratch buffer to the caller's buffer.

The scratch buffer is allocated during allocation time of the CTR DRBG
as its access is protected with the DRBG mutex.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-11-30 19:46:44 +08:00
Stephan Mueller 3cfc3b9721 crypto: drbg - use aligned buffers
Hardware cipher implementation may require aligned buffers. All buffers
that potentially are processed with a cipher are now aligned.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-06-15 17:07:53 +08:00
Stephan Mueller 3559128521 crypto: drbg - use CTR AES instead of ECB AES
The CTR DRBG derives its random data from the CTR that is encrypted with
AES.

This patch now changes the CTR DRBG implementation such that the
CTR AES mode is employed. This allows the use of steamlined CTR AES
implementation such as ctr-aes-aesni.

Unfortunately there are the following subtile changes we need to apply
when using the CTR AES mode:

- the CTR mode increments the counter after the cipher operation, but
  the CTR DRBG requires the increment before the cipher op. Hence, the
  crypto_inc is applied to the counter (drbg->V) once it is
  recalculated.

- the CTR mode wants to encrypt data, but the CTR DRBG is interested in
  the encrypted counter only. The full CTR mode is the XOR of the
  encrypted counter with the plaintext data. To access the encrypted
  counter, the patch uses a NULL data vector as plaintext to be
  "encrypted".

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-06-15 17:07:53 +08:00
Stephan Mueller b361476305 crypto: drbg - remove FIPS 140-2 continuous test
The newly released FIPS 140-2 IG 9.8 specifies that for SP800-90A
compliant DRBGs, the FIPS 140-2 continuous random number generator test
is not required any more.

This patch removes the test and all associated data structures.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-01-25 22:42:11 +08:00
Stephan Mueller 42ea507fae crypto: drbg - reseed often if seedsource is degraded
As required by SP800-90A, the DRBG implements are reseeding threshold.
This threshold is at 2**48 (64 bit) and 2**32 bit (32 bit) as
implemented in drbg_max_requests.

With the recently introduced changes, the DRBG is now always used as a
stdrng which is initialized very early in the boot cycle. To ensure that
sufficient entropy is present, the Jitter RNG is added to even provide
entropy at early boot time.

However, the 2nd seed source, the nonblocking pool, is usually
degraded at that time. Therefore, the DRBG is seeded with the Jitter RNG
(which I believe contains good entropy, which however is questioned by
others) and is seeded with a degradded nonblocking pool. This seed is
now used for quasi the lifetime of the system (2**48 requests is a lot).

The patch now changes the reseed threshold as follows: up until the time
the DRBG obtains a seed from a fully iniitialized nonblocking pool, the
reseeding threshold is lowered such that the DRBG is forced to reseed
itself resonably often. Once it obtains the seed from a fully
initialized nonblocking pool, the reseed threshold is set to the value
required by SP800-90A.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2015-06-10 19:14:05 +08:00
Stephan Mueller 57225e6797 crypto: drbg - Use callback API for random readiness
The get_blocking_random_bytes API is broken because the wait can
be arbitrarily long (potentially forever) so there is no safe way
of calling it from within the kernel.

This patch replaces it with the new callback API which does not
have this problem.

The patch also removes the entropy buffer registered with the DRBG
handle in favor of stack variables to hold the seed data.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2015-06-10 19:14:01 +08:00
Stephan Mueller b8ec5ba42c crypto: drbg - use Jitter RNG to obtain seed
During initialization, the DRBG now tries to allocate a handle of the
Jitter RNG. If such a Jitter RNG is available during seeding, the DRBG
pulls the required entropy/nonce string from get_random_bytes and
concatenates it with a string of equal size from the Jitter RNG. That
combined string is now the seed for the DRBG.

Written differently, the initial seed of the DRBG is now:

get_random_bytes(entropy/nonce) || jitterentropy (entropy/nonce)

If the Jitter RNG is not available, the DRBG only seeds from
get_random_bytes.

CC: Andreas Steffen <andreas.steffen@strongswan.org>
CC: Theodore Ts'o <tytso@mit.edu>
CC: Sandy Harris <sandyinchina@gmail.com>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2015-05-27 17:51:53 +08:00
Stephan Mueller 4c7879907e crypto: drbg - add async seeding operation
The async seeding operation is triggered during initalization right
after the first non-blocking seeding is completed. As required by the
asynchronous operation of random.c, a callback function is provided that
is triggered by random.c once entropy is available. That callback
function performs the actual seeding of the DRBG.

CC: Andreas Steffen <andreas.steffen@strongswan.org>
CC: Theodore Ts'o <tytso@mit.edu>
CC: Sandy Harris <sandyinchina@gmail.com>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2015-05-27 17:51:53 +08:00
Stephan Mueller 3d6a5f75d1 crypto: drbg - prepare for async seeding
In order to prepare for the addition of the asynchronous seeding call,
the invocation of seeding the DRBG is moved out into a helper function.

In addition, a block of memory is allocated during initialization time
that will be used as a scratchpad for obtaining entropy. That scratchpad
is used for the initial seeding operation as well as by the
asynchronous seeding call. The memory must be zeroized every time the
DRBG seeding call succeeds to avoid entropy data lingering in memory.

CC: Andreas Steffen <andreas.steffen@strongswan.org>
CC: Theodore Ts'o <tytso@mit.edu>
CC: Sandy Harris <sandyinchina@gmail.com>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2015-05-27 17:51:53 +08:00
Herbert Xu 8fded5925d crypto: drbg - Convert to new rng interface
This patch converts the DRBG implementation to the new low-level
rng interface.

This allows us to get rid of struct drbg_gen by using the new RNG
API instead.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Stephan Mueller <smueller@chronox.de>
2015-04-22 09:30:17 +08:00
Stephan Mueller 76899a41f8 crypto: drbg - replace spinlock with mutex
The creation of a shadow copy is intended to only hold a short term
lock. But the drawback is that parallel users have a very similar DRBG
state which only differs by a high-resolution time stamp.

The DRBG will now hold a long term lock. Therefore, the lock is changed
to a mutex which implies that the DRBG can only be used in process
context.

The lock now guards the instantiation as well as the entire DRBG
generation operation. Therefore, multiple callers are fully serialized
when generating a random number.

As the locking is changed to use a long-term lock to avoid such similar
DRBG states, the entire creation and maintenance of a shadow copy can be
removed.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2015-04-21 09:14:45 +08:00
Stephan Mueller b9347aff91 crypto: drbg - fix maximum value checks on 32 bit systems
The maximum values for additional input string or generated blocks is
larger than 1<<32. To ensure a sensible value on 32 bit systems, return
SIZE_MAX on 32 bit systems. This value is lower than the maximum
allowed values defined in SP800-90A. The standard allow lower maximum
values, but not larger values.

SIZE_MAX - 1 is used for drbg_max_addtl to allow
drbg_healthcheck_sanity to check the enforcement of the variable
without wrapping.

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2014-08-26 16:58:05 +08:00
Stephan Mueller 05c81ccd90 crypto: drbg - remove configuration of fixed values
SP800-90A mandates several hard-coded values. The old drbg_cores allows
the setting of these values per DRBG implementation. However, due to the
hard requirement of SP800-90A, these values are now returned globally
for each DRBG.

The ability to set such values per DRBG is therefore removed.

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2014-08-25 20:34:12 +08:00
Stephan Mueller 27e4de2bd1 crypto: drbg - Mix a time stamp into DRBG state
The current locking approach of the DRBG tries to keep the protected
code paths very minimal. It is therefore possible that two threads query
one DRBG instance at the same time. When thread A requests random
numbers, a shadow copy of the DRBG state is created upon which the
request for A is processed. After finishing the state for A's request is
merged back into the DRBG state. If now thread B requests random numbers
from the same DRBG after the request for thread A is received, but
before A's shadow state is merged back, the random numbers for B will be
identical to the ones for A. Please note that the time window is very
small for this scenario.

To prevent that there is even a theoretical chance for thread A and B
having the same DRBG state, the current time stamp is provided as
additional information string for each new request.

The addition of the time stamp as additional information string implies
that now all generate functions must be capable to process a linked
list with additional information strings instead of a scalar.

CC: Rafael Aquini <aquini@redhat.com>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2014-07-08 21:18:25 +08:00
Stephan Mueller 8c98716601 crypto: drbg - use of kernel linked list
The DRBG-style linked list to manage input data that is fed into the
cipher invocations is replaced with the kernel linked list
implementation.

The change is transparent to users of the interfaces offered by the
DRBG. Therefore, no changes to the testmgr code is needed.

Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2014-07-04 21:09:20 +08:00
Stephan Mueller 3e16f959b9 crypto: drbg - header file for DRBG
The header file includes the definition of:

* DRBG data structures with
        - struct drbg_state as main structure
        - struct drbg_core referencing the backend ciphers
        - struct drbg_state_ops callbach handlers for specific code
          supporting the Hash, HMAC, CTR DRBG implementations
        - struct drbg_conc defining a linked list for input data
        - struct drbg_test_data holding the test "entropy" data for CAVS
          testing and testmgr.c
        - struct drbg_gen allowing test data, additional information
          string and personalization string data to be funneled through
          the kernel crypto API -- the DRBG requires additional
          parameters when invoking the reset and random number
          generation requests than intended by the kernel crypto API

* wrapper function to the kernel crypto API functions using struct
  drbg_gen to pass through all data needed for DRBG

* wrapper functions to kernel crypto API functions usable for testing
  code to inject test_data into the DRBG as needed by CAVS testing and
  testmgr.c.

* DRBG flags required for the operation of the DRBG and for selecting
  the particular DRBG type and backend cipher

* getter functions for data from struct drbg_core

Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2014-06-20 21:26:09 +08:00