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In aes-neonbs, instead of going through the crypto API for the parts
that the bit-sliced AES code doesn't handle, namely AES-CBC encryption
and single-block AES, just call the ARM scalar AES cipher directly.
This basically goes back to the original approach that was used before
commit b56f5cbc7e08 ("crypto: arm/aes-neonbs - resolve fallback cipher
at runtime"). Calling the ARM scalar AES cipher directly is faster,
simpler, and avoids any chance of bugs specific to the use of fallback
ciphers such as module loading deadlocks which have happened twice. The
deadlocks turned out to be fixable in other ways, but there's no need to
rely on anything so fragile in the first place.
The rationale for the above-mentioned commit was to allow people to
choose to use a time-invariant AES implementation for the fallback
cipher. There are a couple problems with that rationale, though:
- In practice the ARM scalar AES cipher (aes-arm) was used anyway, since
it has a higher priority than aes-fixed-time. Users *could* go out of
their way to disable or blacklist aes-arm, or to lower its priority
using NETLINK_CRYPTO, but very few users customize the crypto API to
this extent. Systems with the ARMv8 Crypto Extensions used aes-ce,
but the bit-sliced algorithms are irrelevant on such systems anyway.
- Since commit 913a3aa07d16 ("crypto: arm/aes - add some hardening
against cache-timing attacks"), the ARM scalar AES cipher is partially
hardened against cache-timing attacks. It actually works like
aes-fixed-time, in that it disables interrupts and prefetches its
lookup table. It does use a larger table than aes-fixed-time, but
even so, it is not clear that aes-fixed-time is meaningfully more
time-invariant than aes-arm. And of course, the real solution for
time-invariant AES is to use a CPU that supports AES instructions.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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The helper crypto_tfm_ctx is only used by the Crypto API algorithm
code and should really be in algapi.h. However, for historical
reasons many files relied on it to be in crypto.h. This patch
changes those files to use algapi.h instead in prepartion for a
move.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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The scalar table based AES routines are not used by other drivers, so
let's keep it that way and unexport the symbols.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Rename some local AES encrypt/decrypt routines so they don't clash with
the names we are about to introduce for the routines exposed by the
generic AES library.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Based on 2 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 version 2 as
published by the free software foundation
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license version 2 as
published by the free software foundation #
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 4122 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Enrico Weigelt <info@metux.net>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190604081206.933168790@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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This replaces the scalar AES cipher that originates in the OpenSSL project
with a new implementation that is ~15% (*) faster (on modern cores), and
reuses the lookup tables and the key schedule generation routines from the
generic C implementation (which is usually compiled in anyway due to
networking and other subsystems depending on it).
Note that the bit sliced NEON code for AES still depends on the scalar cipher
that this patch replaces, so it is not removed entirely yet.
* On Cortex-A57, the performance increases from 17.0 to 14.9 cycles per byte
for 128-bit keys.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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