diff options
author | Ard Biesheuvel <ardb@kernel.org> | 2019-11-08 13:22:08 +0100 |
---|---|---|
committer | Herbert Xu <herbert@gondor.apana.org.au> | 2019-11-17 02:02:39 +0100 |
commit | 5fb8ef25803ef33e2eb60b626435828b937bed75 (patch) | |
tree | 156401ad072c1acc18f74cbdf8eb31859191b9ac /lib | |
parent | crypto: lib - tidy up lib/crypto Kconfig and Makefile (diff) | |
download | linux-5fb8ef25803ef33e2eb60b626435828b937bed75.tar.xz linux-5fb8ef25803ef33e2eb60b626435828b937bed75.zip |
crypto: chacha - move existing library code into lib/crypto
Currently, our generic ChaCha implementation consists of a permute
function in lib/chacha.c that operates on the 64-byte ChaCha state
directly [and which is always included into the core kernel since it
is used by the /dev/random driver], and the crypto API plumbing to
expose it as a skcipher.
In order to support in-kernel users that need the ChaCha streamcipher
but have no need [or tolerance] for going through the abstractions of
the crypto API, let's expose the streamcipher bits via a library API
as well, in a way that permits the implementation to be superseded by
an architecture specific one if provided.
So move the streamcipher code into a separate module in lib/crypto,
and expose the init() and crypt() routines to users of the library.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'lib')
-rw-r--r-- | lib/Makefile | 3 | ||||
-rw-r--r-- | lib/crypto/Kconfig | 26 | ||||
-rw-r--r-- | lib/crypto/Makefile | 4 | ||||
-rw-r--r-- | lib/crypto/chacha.c (renamed from lib/chacha.c) | 20 | ||||
-rw-r--r-- | lib/crypto/libchacha.c | 35 |
5 files changed, 77 insertions, 11 deletions
diff --git a/lib/Makefile b/lib/Makefile index c5892807e06f..5af38fd5cc60 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -26,8 +26,7 @@ endif lib-y := ctype.o string.o vsprintf.o cmdline.o \ rbtree.o radix-tree.o timerqueue.o xarray.o \ - idr.o extable.o \ - sha1.o chacha.o irq_regs.o argv_split.o \ + idr.o extable.o sha1.o irq_regs.o argv_split.o \ flex_proportions.o ratelimit.o show_mem.o \ is_single_threaded.o plist.o decompress.o kobject_uevent.o \ earlycpio.o seq_buf.o siphash.o dec_and_lock.o \ diff --git a/lib/crypto/Kconfig b/lib/crypto/Kconfig index 261430051595..6a11931ae105 100644 --- a/lib/crypto/Kconfig +++ b/lib/crypto/Kconfig @@ -8,6 +8,32 @@ config CRYPTO_LIB_AES config CRYPTO_LIB_ARC4 tristate +config CRYPTO_ARCH_HAVE_LIB_CHACHA + tristate + help + Declares whether the architecture provides an arch-specific + accelerated implementation of the ChaCha library interface, + either builtin or as a module. + +config CRYPTO_LIB_CHACHA_GENERIC + tristate + select CRYPTO_ALGAPI + help + This symbol can be depended upon by arch implementations of the + ChaCha library interface that require the generic code as a + fallback, e.g., for SIMD implementations. If no arch specific + implementation is enabled, this implementation serves the users + of CRYPTO_LIB_CHACHA. + +config CRYPTO_LIB_CHACHA + tristate "ChaCha library interface" + depends on CRYPTO_ARCH_HAVE_LIB_CHACHA || !CRYPTO_ARCH_HAVE_LIB_CHACHA + select CRYPTO_LIB_CHACHA_GENERIC if CRYPTO_ARCH_HAVE_LIB_CHACHA=n + help + Enable the ChaCha library interface. This interface may be fulfilled + by either the generic implementation or an arch-specific one, if one + is available and enabled. + config CRYPTO_LIB_DES tristate diff --git a/lib/crypto/Makefile b/lib/crypto/Makefile index 63de4cb3fcf8..0ce40604e104 100644 --- a/lib/crypto/Makefile +++ b/lib/crypto/Makefile @@ -1,5 +1,9 @@ # SPDX-License-Identifier: GPL-2.0 +# chacha is used by the /dev/random driver which is always builtin +obj-y += chacha.o +obj-$(CONFIG_CRYPTO_LIB_CHACHA_GENERIC) += libchacha.o + obj-$(CONFIG_CRYPTO_LIB_AES) += libaes.o libaes-y := aes.o diff --git a/lib/chacha.c b/lib/crypto/chacha.c index c7c9826564d3..65ead6b0c7e0 100644 --- a/lib/chacha.c +++ b/lib/crypto/chacha.c @@ -5,9 +5,11 @@ * Copyright (C) 2015 Martin Willi */ +#include <linux/bug.h> #include <linux/kernel.h> #include <linux/export.h> #include <linux/bitops.h> +#include <linux/string.h> #include <linux/cryptohash.h> #include <asm/unaligned.h> #include <crypto/chacha.h> @@ -72,7 +74,7 @@ static void chacha_permute(u32 *x, int nrounds) * The caller has already converted the endianness of the input. This function * also handles incrementing the block counter in the input matrix. */ -void chacha_block(u32 *state, u8 *stream, int nrounds) +void chacha_block_generic(u32 *state, u8 *stream, int nrounds) { u32 x[16]; int i; @@ -86,11 +88,11 @@ void chacha_block(u32 *state, u8 *stream, int nrounds) state[12]++; } -EXPORT_SYMBOL(chacha_block); +EXPORT_SYMBOL(chacha_block_generic); /** - * hchacha_block - abbreviated ChaCha core, for XChaCha - * @in: input state matrix (16 32-bit words) + * hchacha_block_generic - abbreviated ChaCha core, for XChaCha + * @state: input state matrix (16 32-bit words) * @out: output (8 32-bit words) * @nrounds: number of rounds (20 or 12; 20 is recommended) * @@ -99,15 +101,15 @@ EXPORT_SYMBOL(chacha_block); * skips the final addition of the initial state, and outputs only certain words * of the state. It should not be used for streaming directly. */ -void hchacha_block(const u32 *in, u32 *out, int nrounds) +void hchacha_block_generic(const u32 *state, u32 *stream, int nrounds) { u32 x[16]; - memcpy(x, in, 64); + memcpy(x, state, 64); chacha_permute(x, nrounds); - memcpy(&out[0], &x[0], 16); - memcpy(&out[4], &x[12], 16); + memcpy(&stream[0], &x[0], 16); + memcpy(&stream[4], &x[12], 16); } -EXPORT_SYMBOL(hchacha_block); +EXPORT_SYMBOL(hchacha_block_generic); diff --git a/lib/crypto/libchacha.c b/lib/crypto/libchacha.c new file mode 100644 index 000000000000..dabc3accae05 --- /dev/null +++ b/lib/crypto/libchacha.c @@ -0,0 +1,35 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * The ChaCha stream cipher (RFC7539) + * + * Copyright (C) 2015 Martin Willi + */ + +#include <linux/kernel.h> +#include <linux/export.h> +#include <linux/module.h> + +#include <crypto/algapi.h> // for crypto_xor_cpy +#include <crypto/chacha.h> + +void chacha_crypt_generic(u32 *state, u8 *dst, const u8 *src, + unsigned int bytes, int nrounds) +{ + /* aligned to potentially speed up crypto_xor() */ + u8 stream[CHACHA_BLOCK_SIZE] __aligned(sizeof(long)); + + while (bytes >= CHACHA_BLOCK_SIZE) { + chacha_block_generic(state, stream, nrounds); + crypto_xor_cpy(dst, src, stream, CHACHA_BLOCK_SIZE); + bytes -= CHACHA_BLOCK_SIZE; + dst += CHACHA_BLOCK_SIZE; + src += CHACHA_BLOCK_SIZE; + } + if (bytes) { + chacha_block_generic(state, stream, nrounds); + crypto_xor_cpy(dst, src, stream, bytes); + } +} +EXPORT_SYMBOL(chacha_crypt_generic); + +MODULE_LICENSE("GPL"); |