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>
The header file algapi.h includes skbuff.h unnecessarily since
all we need is a forward declaration for struct sk_buff. This
patch removes that inclusion.
Unfortunately skbuff.h pulls in a lot of things and drivers over
the years have come to rely on it so this patch adds a lot of
missing inclusions that result from this.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch moves crypto_yield into internal.h as it's only used
by internal code such as skcipher. It also adds a missing inclusion
of sched.h which is required for cond_resched.
The header files in internal.h have been cleaned up to remove some
ancient junk and add some more specific inclusions.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Introduce a new algorithm flag CRYPTO_ALG_ALLOCATES_MEMORY. If this
flag is set, then the driver allocates memory in its request routine.
Such drivers are not suitable for disk encryption because GFP_ATOMIC
allocation can fail anytime (causing random I/O errors) and GFP_KERNEL
allocation can recurse into the block layer, causing a deadlock.
For now, this flag is only implemented for some algorithm types. We
also assume some usage constraints for it to be meaningful, since there
are lots of edge cases the crypto API allows (e.g., misaligned or
fragmented scatterlists) that mean that nearly any crypto algorithm can
allocate memory in some case. See the comment for details.
Also add this flag to CRYPTO_ALG_INHERITED_FLAGS so that when a template
is instantiated, this flag is set on the template instance if it is set
on any algorithm the instance uses.
Based on a patch by Mikulas Patocka <mpatocka@redhat.com>
(https://lore.kernel.org/r/alpine.LRH.2.02.2006301414580.30526@file01.intranet.prod.int.rdu2.redhat.com).
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
CRYPTO_ALG_NEED_FALLBACK is handled inconsistently. When it's requested
to be clear, some templates propagate that request to child algorithms,
while others don't.
It's apparently desired for NEED_FALLBACK to be propagated, to avoid
deadlocks where a module tries to load itself while it's being
initialized, and to avoid unnecessarily complex fallback chains where we
have e.g. cbc-aes-$driver falling back to cbc(aes-$driver) where
aes-$driver itself falls back to aes-generic, instead of cbc-aes-$driver
simply falling back to cbc(aes-generic). There have been a number of
fixes to this effect:
commit 89027579bc ("crypto: xts - Propagate NEED_FALLBACK bit")
commit d2c2a85cfe ("crypto: ctr - Propagate NEED_FALLBACK bit")
commit e6c2e65c70 ("crypto: cbc - Propagate NEED_FALLBACK bit")
But it seems that other templates can have the same problems too.
To avoid this whack-a-mole, just add NEED_FALLBACK to INHERITED_FLAGS so
that it's always inherited.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The flag CRYPTO_ALG_ASYNC is "inherited" in the sense that when a
template is instantiated, the template will have CRYPTO_ALG_ASYNC set if
any of the algorithms it uses has CRYPTO_ALG_ASYNC set.
We'd like to add a second flag (CRYPTO_ALG_ALLOCATES_MEMORY) that gets
"inherited" in the same way. This is difficult because the handling of
CRYPTO_ALG_ASYNC is hardcoded everywhere. Address this by:
- Add CRYPTO_ALG_INHERITED_FLAGS, which contains the set of flags that
have these inheritance semantics.
- Add crypto_algt_inherited_mask(), for use by template ->create()
methods. It returns any of these flags that the user asked to be
unset and thus must be passed in the 'mask' to crypto_grab_*().
- Also modify crypto_check_attr_type() to handle computing the 'mask'
so that most templates can just use this.
- Make crypto_grab_*() propagate these flags to the template instance
being created so that templates don't have to do this themselves.
Make crypto/simd.c propagate these flags too, since it "wraps" another
algorithm, similar to a template.
Based on a patch by Mikulas Patocka <mpatocka@redhat.com>
(https://lore.kernel.org/r/alpine.LRH.2.02.2006301414580.30526@file01.intranet.prod.int.rdu2.redhat.com).
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Add crypto_enqueue_request_head function that enqueues a
request in front of queue.
This will be used in crypto-engine, on error path. In case a request
was not executed by hardware, enqueue it back in front of queue (to
keep the order of requests).
Signed-off-by: Iuliana Prodan <iuliana.prodan@nxp.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Now that all templates provide a ->create() method which creates an
instance, installs a strongly-typed ->free() method directly to it, and
registers it, the older ->alloc() and ->free() methods in
'struct crypto_template' are no longer used. Remove them.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Now that crypto_init_spawn() is only called by crypto_grab_spawn(),
simplify things by moving its functionality into crypto_grab_spawn().
In the process of doing this, also be more consistent about when the
spawn and instance are updated, and remove the crypto_spawn::dropref
flag since now it's always set.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Remove lots of helper functions that were previously used for
instantiating crypto templates, but are now unused:
- crypto_get_attr_alg() and similar functions looked up an inner
algorithm directly from a template parameter. These were replaced
with getting the algorithm's name, then calling crypto_grab_*().
- crypto_init_spawn2() and similar functions initialized a spawn, given
an algorithm. Similarly, these were replaced with crypto_grab_*().
- crypto_alloc_instance() and similar functions allocated an instance
with a single spawn, given the inner algorithm. These aren't useful
anymore since crypto_grab_*() need the instance allocated first.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Now that all users of single-block cipher spawns have been converted to
use 'struct crypto_cipher_spawn' rather than the less specifically typed
'struct crypto_spawn', make crypto_spawn_cipher() take a pointer to a
'struct crypto_cipher_spawn' rather than a 'struct crypto_spawn'.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Currently, "cipher" (single-block cipher) spawns are usually initialized
by using crypto_get_attr_alg() to look up the algorithm, then calling
crypto_init_spawn(). In one case, crypto_grab_spawn() is used directly.
The former way is different from how skcipher, aead, and akcipher spawns
are initialized (they use crypto_grab_*()), and for no good reason.
This difference introduces unnecessary complexity.
The crypto_grab_*() functions used to have some problems, like not
holding a reference to the algorithm and requiring the caller to
initialize spawn->base.inst. But those problems are fixed now.
Also, the cipher spawns are not strongly typed; e.g., the API requires
that the user manually specify the flags CRYPTO_ALG_TYPE_CIPHER and
CRYPTO_ALG_TYPE_MASK. Though the "cipher" algorithm type itself isn't
yet strongly typed, we can start by making the spawns strongly typed.
So, let's introduce a new 'struct crypto_cipher_spawn', and functions
crypto_grab_cipher() and crypto_drop_cipher() to grab and drop them.
Later patches will convert all cipher spawns to use these, then make
crypto_spawn_cipher() take 'struct crypto_cipher_spawn' as well, instead
of a bare 'struct crypto_spawn' as it currently does.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Currently, crypto_spawn::inst is first used temporarily to pass the
instance to crypto_grab_spawn(). Then crypto_init_spawn() overwrites it
with crypto_spawn::next, which shares the same union. Finally,
crypto_spawn::inst is set again when the instance is registered.
Make this less convoluted by just passing the instance as an argument to
crypto_grab_spawn() instead.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch changes crypto_grab_spawn to retain the reference count
on the algorithm. This is because the caller needs to access the
algorithm parameters and without the reference count the algorithm
can be freed at any time.
The reference count will be subsequently dropped by the crypto API
once the instance has been registered. The helper crypto_drop_spawn
will also conditionally drop the reference count depending on whether
it has been registered.
Note that the code is actually added to crypto_init_spawn. However,
unless the caller activates this by setting spawn->dropref beforehand
then nothing happens. The only caller that sets dropref is currently
crypto_grab_spawn.
Once all legacy users of crypto_init_spawn disappear, then we can
kill the dropref flag.
Internally each instance will maintain a list of its spawns prior
to registration. This memory used by this list is shared with
other fields that are only used after registration. In order for
this to work a new flag spawn->registered is added to indicate
whether spawn->inst can be used.
Fixes: d6ef2f198d ("crypto: api - Add crypto_grab_spawn primitive")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Some of the algorithm unregistration functions return -ENOENT when asked
to unregister a non-registered algorithm, while others always return 0
or always return void. But no users check the return value, except for
two of the bulk unregistration functions which print a message on error
but still always return 0 to their caller, and crypto_del_alg() which
calls crypto_unregister_instance() which always returns 0.
Since unregistering a non-registered algorithm is always a kernel bug
but there isn't anything callers should do to handle this situation at
runtime, let's simplify things by making all the unregistration
functions return void, and moving the error message into
crypto_unregister_alg() and upgrading it to a WARN().
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Currently when a spawn is removed we will zap its alg field.
This is racy because the spawn could belong to an unregistered
instance which may dereference the spawn->alg field.
This patch fixes this by keeping spawn->alg constant and instead
adding a new spawn->dead field to indicate that a spawn is going
away.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Now that all users of the deprecated ablkcipher interface have been
moved to the skcipher interface, ablkcipher is no longer used and
can be removed.
Reviewed-by: Eric Biggers <ebiggers@kernel.org>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Now that all "blkcipher" algorithms have been converted to "skcipher",
remove the blkcipher algorithm type.
The skcipher (symmetric key cipher) algorithm type was introduced a few
years ago to replace both blkcipher and ablkcipher (synchronous and
asynchronous block cipher). The advantages of skcipher include:
- A much less confusing name, since none of these algorithm types have
ever actually been for raw block ciphers, but rather for all
length-preserving encryption modes including block cipher modes of
operation, stream ciphers, and other length-preserving modes.
- It unified blkcipher and ablkcipher into a single algorithm type
which supports both synchronous and asynchronous implementations.
Note, blkcipher already operated only on scatterlists, so the fact
that skcipher does too isn't a regression in functionality.
- Better type safety by using struct skcipher_alg, struct
crypto_skcipher, etc. instead of crypto_alg, crypto_tfm, etc.
- It sometimes simplifies the implementations of algorithms.
Also, the blkcipher API was no longer being tested.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
While looking at CONFIG_PREEMPT dependencies treewide the #ifdef in
crypto_yield() matched.
CONFIG_PREEMPT and CONFIG_PREEMPT_VOLUNTARY are mutually exclusive so the
extra !CONFIG_PREEMPT conditional is redundant.
cond_resched() has only an effect when CONFIG_PREEMPT_VOLUNTARY is set,
otherwise it's a stub which the compiler optimizes out.
Remove the whole conditional.
No functional change.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-crypto@vger.kernel.org
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Pull crypto updates from Herbert Xu:
"Here is the crypto update for 5.3:
API:
- Test shash interface directly in testmgr
- cra_driver_name is now mandatory
Algorithms:
- Replace arc4 crypto_cipher with library helper
- Implement 5 way interleave for ECB, CBC and CTR on arm64
- Add xxhash
- Add continuous self-test on noise source to drbg
- Update jitter RNG
Drivers:
- Add support for SHA204A random number generator
- Add support for 7211 in iproc-rng200
- Fix fuzz test failures in inside-secure
- Fix fuzz test failures in talitos
- Fix fuzz test failures in qat"
* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (143 commits)
crypto: stm32/hash - remove interruptible condition for dma
crypto: stm32/hash - Fix hmac issue more than 256 bytes
crypto: stm32/crc32 - rename driver file
crypto: amcc - remove memset after dma_alloc_coherent
crypto: ccp - Switch to SPDX license identifiers
crypto: ccp - Validate the the error value used to index error messages
crypto: doc - Fix formatting of new crypto engine content
crypto: doc - Add parameter documentation
crypto: arm64/aes-ce - implement 5 way interleave for ECB, CBC and CTR
crypto: arm64/aes-ce - add 5 way interleave routines
crypto: talitos - drop icv_ool
crypto: talitos - fix hash on SEC1.
crypto: talitos - move struct talitos_edesc into talitos.h
lib/scatterlist: Fix mapping iterator when sg->offset is greater than PAGE_SIZE
crypto/NX: Set receive window credits to max number of CRBs in RxFIFO
crypto: asymmetric_keys - select CRYPTO_HASH where needed
crypto: serpent - mark __serpent_setkey_sbox noinline
crypto: testmgr - dynamically allocate crypto_shash
crypto: testmgr - dynamically allocate testvec_config
crypto: talitos - eliminate unneeded 'done' functions at build time
...
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-or-later
has been chosen to replace the boilerplate/reference in 3029 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Remove the crypto_tfm_in_queue() function, which is unused.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch add a helper to (un)register a array of templates. The
following patches will use this helper to simplify the code.
Signed-off-by: Xiongfeng Wang <xiongfeng.wang@linaro.org>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Now that all "blkcipher" templates have been converted to "skcipher",
crypto_alloc_instance() is no longer used. And it's not useful any
longer as it creates an old-style weakly typed instance rather than a
new-style strongly typed instance. So remove it, and now that the name
is freed up rename crypto_alloc_instance2() to crypto_alloc_instance().
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Introduce a facility that can be used to receive a notification
callback when a new algorithm becomes available. This can be used by
existing crypto registrations to trigger a switch from a software-only
algorithm to a hardware-accelerated version.
A new CRYPTO_MSG_ALG_LOADED state is introduced to the existing crypto
notification chain, and the register/unregister functions are exported
so they can be called by subsystems outside of crypto.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Suggested-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
In the quest to remove all stack VLA usage from the kernel[1], this
exposes a new general upper bound on crypto blocksize and alignmask
(higher than for the existing cipher limits) for VLA removal,
and introduces new checks.
At present, the highest cra_alignmask in the kernel is 63. The highest
cra_blocksize is 144 (SHA3_224_BLOCK_SIZE, 18 8-byte words). For the
new blocksize limit, I went with 160 (20 8-byte words).
[1] https://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
In preparation for the removal of VLAs[1] from crypto code.
We create 2 new compile-time constants: all ciphers implemented
in Linux have a block size less than or equal to 16 bytes and
the most demanding hw require 16 bytes alignment for the block
buffer.
We also enforce these limits in crypto_check_alg when a new
cipher is registered.
[1] http://lkml.kernel.org/r/CA+55aFzCG-zNmZwX4A2FQpadafLfEzK6CC=qPXydAacU1RqZWA@mail.gmail.com
Signed-off-by: Salvatore Mesoraca <s.mesoraca16@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The lookup function in crypto_type was only used for the implicit
IV generators which have been completely removed from the crypto
API.
This patch removes the lookup function as it is now useless.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
There are quite a number of occurrences in the kernel of the pattern
if (dst != src)
memcpy(dst, src, walk.total % AES_BLOCK_SIZE);
crypto_xor(dst, final, walk.total % AES_BLOCK_SIZE);
or
crypto_xor(keystream, src, nbytes);
memcpy(dst, keystream, nbytes);
where crypto_xor() is preceded or followed by a memcpy() invocation
that is only there because crypto_xor() uses its output parameter as
one of the inputs. To avoid having to add new instances of this pattern
in the arm64 code, which will be refactored to implement non-SIMD
fallbacks, add an alternative implementation called crypto_xor_cpy(),
taking separate input and output arguments. This removes the need for
the separate memcpy().
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
In preparation of introducing crypto_xor_cpy(), which will use separate
operands for input and output, modify the __crypto_xor() implementation,
which it will share with the existing crypto_xor(), which provides the
actual functionality when not using the inline version.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch adds crypto_requires_off which is an extension of
crypto_requires_sync for similar bits such as NEED_FALLBACK.
Cc: stable@vger.kernel.org #4.10
Suggested-by: Marcelo Cerri <marcelo.cerri@canonical.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Instead of unconditionally forcing 4 byte alignment for all generic
chaining modes that rely on crypto_xor() or crypto_inc() (which may
result in unnecessary copying of data when the underlying hardware
can perform unaligned accesses efficiently), make those functions
deal with unaligned input explicitly, but only if the Kconfig symbol
HAVE_EFFICIENT_UNALIGNED_ACCESS is set. This will allow us to drop
the alignmasks from the CBC, CMAC, CTR, CTS, PCBC and SEQIV drivers.
For crypto_inc(), this simply involves making the 4-byte stride
conditional on HAVE_EFFICIENT_UNALIGNED_ACCESS being set, given that
it typically operates on 16 byte buffers.
For crypto_xor(), an algorithm is implemented that simply runs through
the input using the largest strides possible if unaligned accesses are
allowed. If they are not, an optimal sequence of memory accesses is
emitted that takes the relative alignment of the input buffers into
account, e.g., if the relative misalignment of dst and src is 4 bytes,
the entire xor operation will be completed using 4 byte loads and stores
(modulo unaligned bits at the start and end). Note that all expressions
involving misalign are simply eliminated by the compiler when
HAVE_EFFICIENT_UNALIGNED_ACCESS is defined.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch move the whole crypto engine API to its own header
crypto/engine.h.
Signed-off-by: Corentin Labbe <clabbe.montjoie@gmail.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
When hard preemption is enabled there is no need to explicitly
call crypto_yield. This patch eliminates it if that is the case.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch adds the helper crypto_inst_setname because the current
helper crypto_alloc_instance2 is no longer useful given that we
now look up the algorithm after we allocate the instance object.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch removes all traces of the crypto_hash interface, now
that everyone has switched over to shash or ahash.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Now block cipher engines need to implement and maintain their own queue/thread
for processing requests, moreover currently helpers provided for only the queue
itself (in crypto_enqueue_request() and crypto_dequeue_request()) but they
don't help with the mechanics of driving the hardware (things like running the
request immediately, DMA map it or providing a thread to process the queue in)
even though a lot of that code really shouldn't vary that much from device to
device.
Thus this patch provides a mechanism for pushing requests to the hardware
as it becomes free that drivers could use. And this framework is patterned
on the SPI code and has worked out well there.
(https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/
drivers/spi/spi.c?id=ffbbdd21329f3e15eeca6df2d4bc11c04d9d91c0)
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch introduces crypto_queue_len() helper function to help to get the
queue length in the crypto queue list now.
Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Currently the task of freeing an instance is given to the crypto
template. However, it has no type information on the instance so
we have to resort to checking type information at runtime.
This patch introduces a free function to crypto_type that will be
used to free an instance. This can then be used to free an instance
in a type-safe manner.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch converts the top-level aead interface to the new style.
All user-level AEAD interface code have been moved into crypto/aead.h.
The allocation/free functions have switched over to the new way of
allocating tfms.
This patch also removes the double indrection on setkey so the
indirection now exists only at the alg level.
Apart from these there are no user-visible changes.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch adds a new primitive crypto_grab_spawn which is meant
to replace crypto_init_spawn and crypto_init_spawn2. Under the
new scheme the user no longer has to worry about reference counting
the alg object before it is subsumed by the spawn.
It is pretty much an exact copy of crypto_grab_aead.
Prior to calling this function spawn->frontend and spawn->inst
must have been set.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch makes crypto_unregister_instance take a crypto_instance
instead of a crypto_alg. This allows us to remove a duplicate
CRYPTO_ALG_INSTANCE check in crypto_unregister_instance.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
It makes no sense for crypto_yield() to be defined in scatterwalk.h ,
move it into algapi.h as it's an internal function to crypto API.
Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This adds the function blkcipher_aead_walk_virt_block, which allows the caller
to use the blkcipher walk API to handle the input and output scatterlists.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
In order to allow other uses of the blkcipher walk API than the blkcipher
algos themselves, this patch copies some of the transform data members to the
walk struct so the transform is only accessed at walk init time.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
When comparing MAC hashes, AEAD authentication tags, or other hash
values in the context of authentication or integrity checking, it
is important not to leak timing information to a potential attacker,
i.e. when communication happens over a network.
Bytewise memory comparisons (such as memcmp) are usually optimized so
that they return a nonzero value as soon as a mismatch is found. E.g,
on x86_64/i5 for 512 bytes this can be ~50 cyc for a full mismatch
and up to ~850 cyc for a full match (cold). This early-return behavior
can leak timing information as a side channel, allowing an attacker to
iteratively guess the correct result.
This patch adds a new method crypto_memneq ("memory not equal to each
other") to the crypto API that compares memory areas of the same length
in roughly "constant time" (cache misses could change the timing, but
since they don't reveal information about the content of the strings
being compared, they are effectively benign). Iow, best and worst case
behaviour take the same amount of time to complete (in contrast to
memcmp).
Note that crypto_memneq (unlike memcmp) can only be used to test for
equality or inequality, NOT for lexicographical order. This, however,
is not an issue for its use-cases within the crypto API.
We tried to locate all of the places in the crypto API where memcmp was
being used for authentication or integrity checking, and convert them
over to crypto_memneq.
crypto_memneq is declared noinline, placed in its own source file,
and compiled with optimizations that might increase code size disabled
("Os") because a smart compiler (or LTO) might notice that the return
value is always compared against zero/nonzero, and might then
reintroduce the same early-return optimization that we are trying to
avoid.
Using #pragma or __attribute__ optimization annotations of the code
for disabling optimization was avoided as it seems to be considered
broken or unmaintained for long time in GCC [1]. Therefore, we work
around that by specifying the compile flag for memneq.o directly in
the Makefile. We found that this seems to be most appropriate.
As we use ("Os"), this patch also provides a loop-free "fast-path" for
frequently used 16 byte digests. Similarly to kernel library string
functions, leave an option for future even further optimized architecture
specific assembler implementations.
This was a joint work of James Yonan and Daniel Borkmann. Also thanks
for feedback from Florian Weimer on this and earlier proposals [2].
[1] http://gcc.gnu.org/ml/gcc/2012-07/msg00211.html
[2] https://lkml.org/lkml/2013/2/10/131
Signed-off-by: James Yonan <james@openvpn.net>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Cc: Florian Weimer <fw@deneb.enyo.de>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
We leak the crypto instance when we unregister an instance with
crypto_del_alg(). Therefore we introduce crypto_unregister_instance()
to unlink the crypto instance from the template's instances list and
to free the recources of the instance properly.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
We add a report function pointer to struct crypto_type. This function
pointer is used from the crypto userspace configuration API to report
crypto algorithms to userspace.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
These are akin to the blkcipher_walk helpers.
The main differences in the async variant are:
1) Only physical walking is supported. We can't hold on to
kmap mappings across the async operation to support virtual
ablkcipher_walk operations anyways.
2) Bounce buffers used for async more need to be persistent and
freed at a later point in time when the async op completes.
Therefore we maintain a list of writeback buffers and require
that the ablkcipher_walk user call the 'complete' operation
so we can copy the bounce buffers out to the real buffers and
free up the bounce buffer chunks.
These interfaces will be used by the new Niagara2 crypto driver.
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
