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A subsequent patch will make the jitterentropy RNG to unconditionally
report health test errors back to callers, independent of whether
fips_enabled is set or not. The DRBG needs access to a functional
jitterentropy instance only in FIPS mode (because it's the only SP800-90B
compliant entropy source as it currently stands). Thus, it is perfectly
fine for the DRBGs to obtain entropy from the jitterentropy source only
on a best effort basis if fips_enabled is off.
Make the DRBGs to ignore jitterentropy failures if fips_enabled is not set.
Signed-off-by: Nicolai Stange <nstange@suse.de>
Reviewed-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
In contrast to the fully prediction resistant 'pr' DRBGs, the 'nopr'
variants get seeded once at boot and reseeded only rarely thereafter,
namely only after 2^20 requests have been served each. AFAICT, this
reseeding based on the number of requests served is primarily motivated
by information theoretic considerations, c.f. NIST SP800-90Ar1,
sec. 8.6.8 ("Reseeding").
However, given the relatively large seed lifetime of 2^20 requests, the
'nopr' DRBGs can hardly be considered to provide any prediction resistance
whatsoever, i.e. to protect against threats like side channel leaks of the
internal DRBG state (think e.g. leaked VM snapshots). This is expected and
completely in line with the 'nopr' naming, but as e.g. the
"drbg_nopr_hmac_sha512" implementation is potentially being used for
providing the "stdrng" and thus, the crypto_default_rng serving the
in-kernel crypto, it would certainly be desirable to achieve at least the
same level of prediction resistance as get_random_bytes() does.
Note that the chacha20 rngs underlying get_random_bytes() get reseeded
every CRNG_RESEED_INTERVAL == 5min: the secondary, per-NUMA node rngs from
the primary one and the primary rng in turn from the entropy pool, provided
sufficient entropy is available.
The 'nopr' DRBGs do draw randomness from get_random_bytes() for their
initial seed already, so making them to reseed themselves periodically from
get_random_bytes() in order to let them benefit from the latter's
prediction resistance is not such a big change conceptually.
In principle, it would have been also possible to make the 'nopr' DRBGs to
periodically invoke a full reseeding operation, i.e. to also consider the
jitterentropy source (if enabled) in addition to get_random_bytes() for the
seed value. However, get_random_bytes() is relatively lightweight as
compared to the jitterentropy generation process and thus, even though the
'nopr' reseeding is supposed to get invoked infrequently, it's IMO still
worthwhile to avoid occasional latency spikes for drbg_generate() and
stick to get_random_bytes() only. As an additional remark, note that
drawing randomness from the non-SP800-90B-conforming get_random_bytes()
only won't adversely affect SP800-90A conformance either: the very same is
being done during boot via drbg_seed_from_random() already once
rng_is_initialized() flips to true and it follows that if the DRBG
implementation does conform to SP800-90A now, it will continue to do so.
Make the 'nopr' DRBGs to reseed themselves periodically from
get_random_bytes() every CRNG_RESEED_INTERVAL == 5min.
More specifically, introduce a new member ->last_seed_time to struct
drbg_state for recording in units of jiffies when the last seeding
operation had taken place. Make __drbg_seed() maintain it and let
drbg_generate() invoke a reseed from get_random_bytes() via
drbg_seed_from_random() if more than 5min have passed by since the last
seeding operation. Be careful to not to reseed if in testing mode though,
or otherwise the drbg related tests in crypto/testmgr.c would fail to
reproduce the expected output.
In order to keep the formatting clean in drbg_generate() wrap the logic
for deciding whether or not a reseed is due in a new helper,
drbg_nopr_reseed_interval_elapsed().
Signed-off-by: Nicolai Stange <nstange@suse.de>
Reviewed-by: Stephan Müller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Now that drbg_prepare_hrng() doesn't do anything but to instantiate a
jitterentropy crypto_rng instance, it looks a little odd to have the
related error handling at its only caller, drbg_instantiate().
Move the handling of jitterentropy allocation failures from
drbg_instantiate() close to the allocation itself in drbg_prepare_hrng().
There is no change in behaviour.
Signed-off-by: Nicolai Stange <nstange@suse.de>
Reviewed-by: Stephan Müller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
get_random_bytes() usually hasn't full entropy available by the time DRBG
instances are first getting seeded from it during boot. Thus, the DRBG
implementation registers random_ready_callbacks which would in turn
schedule some work for reseeding the DRBGs once get_random_bytes() has
sufficient entropy available.
For reference, the relevant history around handling DRBG (re)seeding in
the context of a not yet fully seeded get_random_bytes() is:
commit 16b369a91d ("random: Blocking API for accessing
nonblocking_pool")
commit 4c7879907e ("crypto: drbg - add async seeding operation")
commit 205a525c33 ("random: Add callback API for random pool
readiness")
commit 57225e6797 ("crypto: drbg - Use callback API for random
readiness")
commit c2719503f5 ("random: Remove kernel blocking API")
However, some time later, the initialization state of get_random_bytes()
has been made queryable via rng_is_initialized() introduced with commit
9a47249d44 ("random: Make crng state queryable"). This primitive now
allows for streamlining the DRBG reseeding from get_random_bytes() by
replacing that aforementioned asynchronous work scheduling from
random_ready_callbacks with some simpler, synchronous code in
drbg_generate() next to the related logic already present therein. Apart
from improving overall code readability, this change will also enable DRBG
users to rely on wait_for_random_bytes() for ensuring that the initial
seeding has completed, if desired.
The previous patches already laid the grounds by making drbg_seed() to
record at each DRBG instance whether it was being seeded at a time when
rng_is_initialized() still had been false as indicated by
->seeded == DRBG_SEED_STATE_PARTIAL.
All that remains to be done now is to make drbg_generate() check for this
condition, determine whether rng_is_initialized() has flipped to true in
the meanwhile and invoke a reseed from get_random_bytes() if so.
Make this move:
- rename the former drbg_async_seed() work handler, i.e. the one in charge
of reseeding a DRBG instance from get_random_bytes(), to
"drbg_seed_from_random()",
- change its signature as appropriate, i.e. make it take a struct
drbg_state rather than a work_struct and change its return type from
"void" to "int" in order to allow for passing error information from
e.g. its __drbg_seed() invocation onwards to callers,
- make drbg_generate() invoke this drbg_seed_from_random() once it
encounters a DRBG instance with ->seeded == DRBG_SEED_STATE_PARTIAL by
the time rng_is_initialized() has flipped to true and
- prune everything related to the former, random_ready_callback based
mechanism.
As drbg_seed_from_random() is now getting invoked from drbg_generate() with
the ->drbg_mutex being held, it must not attempt to recursively grab it
once again. Remove the corresponding mutex operations from what is now
drbg_seed_from_random(). Furthermore, as drbg_seed_from_random() can now
report errors directly to its caller, there's no need for it to temporarily
switch the DRBG's ->seeded state to DRBG_SEED_STATE_UNSEEDED so that a
failure of the subsequently invoked __drbg_seed() will get signaled to
drbg_generate(). Don't do it then.
Signed-off-by: Nicolai Stange <nstange@suse.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Since commit 42ea507fae ("crypto: drbg - reseed often if seedsource is
degraded"), the maximum seed lifetime represented by ->reseed_threshold
gets temporarily lowered if the get_random_bytes() source cannot provide
sufficient entropy yet, as is common during boot, and restored back to
the original value again once that has changed.
More specifically, if the add_random_ready_callback() invoked from
drbg_prepare_hrng() in the course of DRBG instantiation does not return
-EALREADY, that is, if get_random_bytes() has not been fully initialized
at this point yet, drbg_prepare_hrng() will lower ->reseed_threshold
to a value of 50. The drbg_async_seed() scheduled from said
random_ready_callback will eventually restore the original value.
A future patch will replace the random_ready_callback based notification
mechanism and thus, there will be no add_random_ready_callback() return
value anymore which could get compared to -EALREADY.
However, there's __drbg_seed() which gets invoked in the course of both,
the DRBG instantiation as well as the eventual reseeding from
get_random_bytes() in aforementioned drbg_async_seed(), if any. Moreover,
it knows about the get_random_bytes() initialization state by the time the
seed data had been obtained from it: the new_seed_state argument introduced
with the previous patch would get set to DRBG_SEED_STATE_PARTIAL in case
get_random_bytes() had not been fully initialized yet and to
DRBG_SEED_STATE_FULL otherwise. Thus, __drbg_seed() provides a convenient
alternative for managing that ->reseed_threshold lowering and restoring at
a central place.
Move all ->reseed_threshold adjustment code from drbg_prepare_hrng() and
drbg_async_seed() respectively to __drbg_seed(). Make __drbg_seed()
lower the ->reseed_threshold to 50 in case its new_seed_state argument
equals DRBG_SEED_STATE_PARTIAL and let it restore the original value
otherwise.
There is no change in behaviour.
Signed-off-by: Nicolai Stange <nstange@suse.de>
Reviewed-by: Stephan Müller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Currently, the DRBG implementation schedules asynchronous works from
random_ready_callbacks for reseeding the DRBG instances with output from
get_random_bytes() once the latter has sufficient entropy available.
However, as the get_random_bytes() initialization state can get queried by
means of rng_is_initialized() now, there is no real need for this
asynchronous reseeding logic anymore and it's better to keep things simple
by doing it synchronously when needed instead, i.e. from drbg_generate()
once rng_is_initialized() has flipped to true.
Of course, for this to work, drbg_generate() would need some means by which
it can tell whether or not rng_is_initialized() has flipped to true since
the last seeding from get_random_bytes(). Or equivalently, whether or not
the last seed from get_random_bytes() has happened when
rng_is_initialized() was still evaluating to false.
As it currently stands, enum drbg_seed_state allows for the representation
of two different DRBG seeding states: DRBG_SEED_STATE_UNSEEDED and
DRBG_SEED_STATE_FULL. The former makes drbg_generate() to invoke a full
reseeding operation involving both, the rather expensive jitterentropy as
well as the get_random_bytes() randomness sources. The DRBG_SEED_STATE_FULL
state on the other hand implies that no reseeding at all is required for a
!->pr DRBG variant.
Introduce the new DRBG_SEED_STATE_PARTIAL state to enum drbg_seed_state for
representing the condition that a DRBG was being seeded when
rng_is_initialized() had still been false. In particular, this new state
implies that
- the given DRBG instance has been fully seeded from the jitterentropy
source (if enabled)
- and drbg_generate() is supposed to reseed from get_random_bytes()
*only* once rng_is_initialized() turns to true.
Up to now, the __drbg_seed() helper used to set the given DRBG instance's
->seeded state to constant DRBG_SEED_STATE_FULL. Introduce a new argument
allowing for the specification of the to be written ->seeded value instead.
Make the first of its two callers, drbg_seed(), determine the appropriate
value based on rng_is_initialized(). The remaining caller,
drbg_async_seed(), is known to get invoked only once rng_is_initialized()
is true, hence let it pass constant DRBG_SEED_STATE_FULL for the new
argument to __drbg_seed().
There is no change in behaviour, except for that the pr_devel() in
drbg_generate() would now report "unseeded" for ->pr DRBG instances which
had last been seeded when rng_is_initialized() was still evaluating to
false.
Signed-off-by: Nicolai Stange <nstange@suse.de>
Reviewed-by: Stephan Müller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
There are two different randomness sources the DRBGs are getting seeded
from, namely the jitterentropy source (if enabled) and get_random_bytes().
At initial DRBG seeding time during boot, the latter might not have
collected sufficient entropy for seeding itself yet and thus, the DRBG
implementation schedules a reseed work from a random_ready_callback once
that has happened. This is particularly important for the !->pr DRBG
instances, for which (almost) no further reseeds are getting triggered
during their lifetime.
Because collecting data from the jitterentropy source is a rather expensive
operation, the aforementioned asynchronously scheduled reseed work
restricts itself to get_random_bytes() only. That is, it in some sense
amends the initial DRBG seed derived from jitterentropy output at full
(estimated) entropy with fresh randomness obtained from get_random_bytes()
once that has been seeded with sufficient entropy itself.
With the advent of rng_is_initialized(), there is no real need for doing
the reseed operation from an asynchronously scheduled work anymore and a
subsequent patch will make it synchronous by moving it next to related
logic already present in drbg_generate().
However, for tracking whether a full reseed including the jitterentropy
source is required or a "partial" reseed involving only get_random_bytes()
would be sufficient already, the boolean struct drbg_state's ->seeded
member must become a tristate value.
Prepare for this by introducing the new enum drbg_seed_state and change
struct drbg_state's ->seeded member's type from bool to that type.
For facilitating review, enum drbg_seed_state is made to only contain
two members corresponding to the former ->seeded values of false and true
resp. at this point: DRBG_SEED_STATE_UNSEEDED and DRBG_SEED_STATE_FULL. A
third one for tracking the intermediate state of "seeded from jitterentropy
only" will be introduced with a subsequent patch.
There is no change in behaviour at this point.
Signed-off-by: Nicolai Stange <nstange@suse.de>
Reviewed-by: Stephan Müller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Coverity warns uf an unused value:
CID 44865 (#2 of 2): Unused value (UNUSED_VALUE)
assigned_value: Assigning value -14 to ret here, but that stored value is
overwritten before it can be used.
2006 int ret = -EFAULT;
...
value_overwrite: Overwriting previous write to ret with value from drbg_seed(drbg, &addtl, false).
2052 ret = drbg_seed(drbg, &addtl, false);
Fix this by removing the variable initializer.
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-crypto@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The default DRBG is the one that has the highest priority. The priority
is defined based on the order of the list drbg_cores[] where the highest
priority is given to the last entry by drbg_fill_array.
With this patch the default DRBG is switched from HMAC SHA256 to HMAC
SHA512 to support compliance with SP800-90B and SP800-90C (current
draft).
The user of the crypto API is completely unaffected by the change.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Acked-by: simo Sorce <simo@redhat.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The cipher routines in the crypto API are mostly intended for templates
implementing skcipher modes generically in software, and shouldn't be
used outside of the crypto subsystem. So move the prototypes and all
related definitions to a new header file under include/crypto/internal.
Also, let's use the new module namespace feature to move the symbol
exports into a new namespace CRYPTO_INTERNAL.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
As said by Linus:
A symmetric naming is only helpful if it implies symmetries in use.
Otherwise it's actively misleading.
In "kzalloc()", the z is meaningful and an important part of what the
caller wants.
In "kzfree()", the z is actively detrimental, because maybe in the
future we really _might_ want to use that "memfill(0xdeadbeef)" or
something. The "zero" part of the interface isn't even _relevant_.
The main reason that kzfree() exists is to clear sensitive information
that should not be leaked to other future users of the same memory
objects.
Rename kzfree() to kfree_sensitive() to follow the example of the recently
added kvfree_sensitive() and make the intention of the API more explicit.
In addition, memzero_explicit() is used to clear the memory to make sure
that it won't get optimized away by the compiler.
The renaming is done by using the command sequence:
git grep -w --name-only kzfree |\
xargs sed -i 's/kzfree/kfree_sensitive/'
followed by some editing of the kfree_sensitive() kerneldoc and adding
a kzfree backward compatibility macro in slab.h.
[akpm@linux-foundation.org: fs/crypto/inline_crypt.c needs linux/slab.h]
[akpm@linux-foundation.org: fix fs/crypto/inline_crypt.c some more]
Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Howells <dhowells@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Joe Perches <joe@perches.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Jason A . Donenfeld" <Jason@zx2c4.com>
Link: http://lkml.kernel.org/r/20200616154311.12314-3-longman@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The Jitter RNG is unconditionally allocated as a seed source follwoing
the patch 97f2650e50. Thus, the instance must always be deallocated.
Reported-by: syzbot+2e635807decef724a1fa@syzkaller.appspotmail.com
Fixes: 97f2650e50 ("crypto: drbg - always seeded with SP800-90B ...")
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Fix to return negative error code -ENOMEM from the kzalloc error handling
case instead of 0, as done elsewhere in this function.
Reported-by: Xiumei Mu <xmu@redhat.com>
Fixes: db07cd26ac ("crypto: drbg - add FIPS 140-2 CTRNG for noise source")
Cc: <stable@vger.kernel.org>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
As the Jitter RNG provides an SP800-90B compliant noise source, use this
noise source always for the (re)seeding of the DRBG.
To make sure the DRBG is always properly seeded, the reseed threshold
is reduced to 1<<20 generate operations.
The Jitter RNG may report health test failures. Such health test
failures are treated as transient as follows. The DRBG will not reseed
from the Jitter RNG (but from get_random_bytes) in case of a health
test failure. Though, it produces the requested random number.
The Jitter RNG has a failure counter where at most 1024 consecutive
resets due to a health test failure are considered as a transient error.
If more consecutive resets are required, the Jitter RNG will return
a permanent error which is returned to the caller by the DRBG. With this
approach, the worst case reseed threshold is significantly lower than
mandated by SP800-90A in order to seed with an SP800-90B noise source:
the DRBG has a reseed threshold of 2^20 * 1024 = 2^30 generate requests.
Yet, in case of a transient Jitter RNG health test failure, the DRBG is
seeded with the data obtained from get_random_bytes.
However, if the Jitter RNG fails during the initial seeding operation
even due to a health test error, the DRBG will send an error to the
caller because at that time, the DRBG has received no seed that is
SP800-90B compliant.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
FIPS 140-2 section 4.9.2 requires a continuous self test of the noise
source. Up to kernel 4.8 drivers/char/random.c provided this continuous
self test. Afterwards it was moved to a location that is inconsistent
with the FIPS 140-2 requirements. The relevant patch was
e192be9d9a .
Thus, the FIPS 140-2 CTRNG is added to the DRBG when it obtains the
seed. This patch resurrects the function drbg_fips_continous_test that
existed some time ago and applies it to the noise sources. The patch
that removed the drbg_fips_continous_test was
b361476305 .
The Jitter RNG implements its own FIPS 140-2 self test and thus does not
need to be subjected to the test in the DRBG.
The patch contains a tiny fix to ensure proper zeroization in case of an
error during the Jitter RNG data gathering.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Reviewed-by: Yann Droneaud <ydroneaud@opteya.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The flags field in 'struct shash_desc' never actually does anything.
The only ostensibly supported flag is CRYPTO_TFM_REQ_MAY_SLEEP.
However, no shash algorithm ever sleeps, making this flag a no-op.
With this being the case, inevitably some users who can't sleep wrongly
pass MAY_SLEEP. These would all need to be fixed if any shash algorithm
actually started sleeping. For example, the shash_ahash_*() functions,
which wrap a shash algorithm with the ahash API, pass through MAY_SLEEP
from the ahash API to the shash API. However, the shash functions are
called under kmap_atomic(), so actually they're assumed to never sleep.
Even if it turns out that some users do need preemption points while
hashing large buffers, we could easily provide a helper function
crypto_shash_update_large() which divides the data into smaller chunks
and calls crypto_shash_update() and cond_resched() for each chunk. It's
not necessary to have a flag in 'struct shash_desc', nor is it necessary
to make individual shash algorithms aware of this at all.
Therefore, remove shash_desc::flags, and document that the
crypto_shash_*() functions can be called from any context.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Use subsys_initcall for registration of all templates and generic
algorithm implementations, rather than module_init. Then change
cryptomgr to use arch_initcall, to place it before the subsys_initcalls.
This is needed so that when both a generic and optimized implementation
of an algorithm are built into the kernel (not loadable modules), the
generic implementation is registered before the optimized one.
Otherwise, the self-tests for the optimized implementation are unable to
allocate the generic implementation for the new comparison fuzz tests.
Note that on arm, a side effect of this change is that self-tests for
generic implementations may run before the unaligned access handler has
been installed. So, unaligned accesses will crash the kernel. This is
arguably a good thing as it makes it easier to detect that type of bug.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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>
During freeing of the internal buffers used by the DRBG, set the pointer
to NULL. It is possible that the context with the freed buffers is
reused. In case of an error during initialization where the pointers
do not yet point to allocated memory, the NULL value prevents a double
free.
Cc: stable@vger.kernel.org
Fixes: 3cfc3b9721 ("crypto: drbg - use aligned buffers")
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Reported-by: syzbot+75397ee3df5c70164154@syzkaller.appspotmail.com
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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>
During the change to use aligned buffers, the deallocation code path was
not updated correctly. The current code tries to free the aligned buffer
pointer and not the original buffer pointer as it is supposed to.
Thus, the code is updated to free the original buffer pointer and set
the aligned buffer pointer that is used throughout the code to NULL.
Fixes: 3cfc3b9721 ("crypto: drbg - use aligned buffers")
CC: <stable@vger.kernel.org>
CC: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
drbg_kcapi_sym_ctr() was using wait_for_completion_interruptible() to
wait for completion of async crypto op but if a signal occurs it
may return before DMA ops of HW crypto provider finish, thus
corrupting the output buffer.
Resolve this by using wait_for_completion() instead.
Reported-by: Eric Biggers <ebiggers3@gmail.com>
Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
CC: stable@vger.kernel.org
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
An SGL to be initialized only once even when its buffers are written
to several times.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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>
The CTR DRBG segments the number of random bytes to be generated into
128 byte blocks. The current code misses the advancement of the output
buffer pointer when the requestor asks for more than 128 bytes of data.
In this case, the next 128 byte block of random numbers is copied to
the beginning of the output buffer again. This implies that only the
first 128 bytes of the output buffer would ever be filled.
The patch adds the advancement of the buffer pointer to fill the entire
buffer.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Fix to return a negative error code from the error handling
case instead of 0.
Signed-off-by: Wei Yongjun <weiyj.lk@gmail.com>
Acked-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
When calling the DRBG health test in FIPS mode, the Jitter RNG is not
yet present in the kernel crypto API which will cause the instantiation
to fail and thus the health test to fail.
As the health tests cover the enforcement of various thresholds, invoke
the functions that are supposed to enforce the thresholds directly.
This patch also saves precious seed.
Reported-by: Tapas Sarangi <TSarangi@trustwave.com>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
We accidentally return PTR_ERR(NULL) which is success but we should
return -ENOMEM.
Fixes: 3559128521 ('crypto: drbg - use CTR AES instead of ECB AES')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Acked-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The TFM object maintains the key for the CTR DRBG.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The CTR DRBG update function performs a full CTR AES operation including
the XOR with "plaintext" data. Hence, remove the XOR from the code and
use the CTR mode to do the XOR.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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>
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>
The CTR DRBG code always set the key for each sym cipher invocation even
though the key has not been changed.
The patch ensures that the setkey is only invoked when a new key is
generated by the DRBG.
With this patch, the CTR DRBG performance increases by more than 150%.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The HMAC implementation allows setting the HMAC key independently from
the hashing operation. Therefore, the key only needs to be set when a
new key is generated.
This patch increases the speed of the HMAC DRBG by at least 35% depending
on the use case.
The patch is fully CAVS tested.
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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>
The drbg_state_ops structures are never modified, so declare them as const.
Done with the help of Coccinelle.
Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Be more verbose and also report ->backend_cra_name when
crypto_alloc_shash() or crypto_alloc_cipher() fail in
drbg_init_hash_kernel() or drbg_init_sym_kernel()
correspondingly.
Example
DRBG: could not allocate digest TFM handle: hmac(sha256)
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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>
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>
This patch adds the stdrng module alias and increases the priority
to ensure that it is loaded in preference to other RNGs.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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>
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>
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>
This patch removes the unnecessary CRYPTO_FIPS ifdef from
drbg_healthcheck_sanity so that the code always gets checked
by the compiler.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Stephan Mueller <smueller@chronox.de>
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>
