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UPSTREAM: crypto: chacha - move existing library code into lib/crypto

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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as well, in a way that permits the implementation to be superseded by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>
(cherry picked from commit 5fb8ef25803ef33e2eb60b626435828b937bed75)
Bug: 152722841
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I7fe321d1fcbaea1dc3f9f65dec74a6f40da2d489
This commit is contained in:
Ard Biesheuvel 2019-11-08 13:22:08 +01:00 committed by Greg Kroah-Hartman
parent c099f33354
commit 2aa92dfe28
12 changed files with 199 additions and 87 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
arch/arm/crypto/chacha-neon-glue.c
View file

@ -20,7 +20,7 @@
*/
#include <crypto/algapi.h>
#include <crypto/chacha.h>
#include <crypto/internal/chacha.h>
#include <crypto/internal/skcipher.h>
#include <linux/kernel.h>
#include <linux/module.h>

2
arch/arm64/crypto/chacha-neon-glue.c
View file

@ -20,7 +20,7 @@
*/
#include <crypto/algapi.h>
#include <crypto/chacha.h>
#include <crypto/internal/chacha.h>
#include <crypto/internal/skcipher.h>
#include <linux/kernel.h>
#include <linux/module.h>

2
arch/x86/crypto/chacha_glue.c
View file

@ -11,7 +11,7 @@
*/
#include <crypto/algapi.h>
#include <crypto/chacha.h>
#include <crypto/internal/chacha.h>
#include <crypto/internal/skcipher.h>
#include <linux/kernel.h>
#include <linux/module.h>

1
crypto/Kconfig
View file

@ -1467,6 +1467,7 @@ config CRYPTO_SALSA20
config CRYPTO_CHACHA20
tristate "ChaCha stream cipher algorithms"
select CRYPTO_LIB_CHACHA_GENERIC
select CRYPTO_BLKCIPHER
help
The ChaCha20, XChaCha20, and XChaCha12 stream cipher algorithms.

62
crypto/chacha_generic.c
View file

@ -12,31 +12,10 @@
#include <asm/unaligned.h>
#include <crypto/algapi.h>
#include <crypto/chacha.h>
#include <crypto/internal/chacha.h>
#include <crypto/internal/skcipher.h>
#include <linux/module.h>
static void chacha_docrypt(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));
if (dst != src)
memcpy(dst, src, bytes);
while (bytes >= CHACHA_BLOCK_SIZE) {
chacha_block(state, stream, nrounds);
crypto_xor(dst, stream, CHACHA_BLOCK_SIZE);
bytes -= CHACHA_BLOCK_SIZE;
dst += CHACHA_BLOCK_SIZE;
}
if (bytes) {
chacha_block(state, stream, nrounds);
crypto_xor(dst, stream, bytes);
}
}
static int chacha_stream_xor(struct skcipher_request *req,
const struct chacha_ctx *ctx, const u8 *iv)
{
@ -54,8 +33,8 @@ static int chacha_stream_xor(struct skcipher_request *req,
if (nbytes < walk.total)
nbytes = round_down(nbytes, walk.stride);
chacha_docrypt(state, walk.dst.virt.addr, walk.src.virt.addr,
nbytes, ctx->nrounds);
chacha_crypt_generic(state, walk.dst.virt.addr,
walk.src.virt.addr, nbytes, ctx->nrounds);
err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
}
@ -64,41 +43,10 @@ static int chacha_stream_xor(struct skcipher_request *req,
void crypto_chacha_init(u32 *state, const struct chacha_ctx *ctx, const u8 *iv)
{
state[0] = 0x61707865; /* "expa" */
state[1] = 0x3320646e; /* "nd 3" */
state[2] = 0x79622d32; /* "2-by" */
state[3] = 0x6b206574; /* "te k" */
state[4] = ctx->key[0];
state[5] = ctx->key[1];
state[6] = ctx->key[2];
state[7] = ctx->key[3];
state[8] = ctx->key[4];
state[9] = ctx->key[5];
state[10] = ctx->key[6];
state[11] = ctx->key[7];
state[12] = get_unaligned_le32(iv + 0);
state[13] = get_unaligned_le32(iv + 4);
state[14] = get_unaligned_le32(iv + 8);
state[15] = get_unaligned_le32(iv + 12);
chacha_init_generic(state, ctx->key, iv);
}
EXPORT_SYMBOL_GPL(crypto_chacha_init);
static int chacha_setkey(struct crypto_skcipher *tfm, const u8 *key,
unsigned int keysize, int nrounds)
{
struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
int i;
if (keysize != CHACHA_KEY_SIZE)
return -EINVAL;
for (i = 0; i < ARRAY_SIZE(ctx->key); i++)
ctx->key[i] = get_unaligned_le32(key + i * sizeof(u32));
ctx->nrounds = nrounds;
return 0;
}
int crypto_chacha20_setkey(struct crypto_skcipher *tfm, const u8 *key,
unsigned int keysize)
{
@ -132,7 +80,7 @@ int crypto_xchacha_crypt(struct skcipher_request *req)
/* Compute the subkey given the original key and first 128 nonce bits */
crypto_chacha_init(state, ctx, req->iv);
hchacha_block(state, subctx.key, ctx->nrounds);
hchacha_block_generic(state, subctx.key, ctx->nrounds);
subctx.nrounds = ctx->nrounds;
/* Build the real IV */

77
include/crypto/chacha.h
View file

@ -15,9 +15,8 @@
#ifndef _CRYPTO_CHACHA_H
#define _CRYPTO_CHACHA_H
#include <crypto/skcipher.h>
#include <asm/unaligned.h>
#include <linux/types.h>
#include <linux/crypto.h>
/* 32-bit stream position, then 96-bit nonce (RFC7539 convention) */
#define CHACHA_IV_SIZE 16
@ -28,26 +27,70 @@
/* 192-bit nonce, then 64-bit stream position */
#define XCHACHA_IV_SIZE 32
struct chacha_ctx {
u32 key[8];
int nrounds;
};
void chacha_block(u32 *state, u8 *stream, int nrounds);
void chacha_block_generic(u32 *state, u8 *stream, int nrounds);
static inline void chacha20_block(u32 *state, u8 *stream)
{
chacha_block(state, stream, 20);
chacha_block_generic(state, stream, 20);
}
void hchacha_block(const u32 *in, u32 *out, int nrounds);
void crypto_chacha_init(u32 *state, const struct chacha_ctx *ctx, const u8 *iv);
void hchacha_block_arch(const u32 *state, u32 *out, int nrounds);
void hchacha_block_generic(const u32 *state, u32 *out, int nrounds);
int crypto_chacha20_setkey(struct crypto_skcipher *tfm, const u8 *key,
unsigned int keysize);
int crypto_chacha12_setkey(struct crypto_skcipher *tfm, const u8 *key,
unsigned int keysize);
static inline void hchacha_block(const u32 *state, u32 *out, int nrounds)
{
if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_CHACHA))
hchacha_block_arch(state, out, nrounds);
else
hchacha_block_generic(state, out, nrounds);
}
int crypto_chacha_crypt(struct skcipher_request *req);
int crypto_xchacha_crypt(struct skcipher_request *req);
void chacha_init_arch(u32 *state, const u32 *key, const u8 *iv);
static inline void chacha_init_generic(u32 *state, const u32 *key, const u8 *iv)
{
state[0] = 0x61707865; /* "expa" */
state[1] = 0x3320646e; /* "nd 3" */
state[2] = 0x79622d32; /* "2-by" */
state[3] = 0x6b206574; /* "te k" */
state[4] = key[0];
state[5] = key[1];
state[6] = key[2];
state[7] = key[3];
state[8] = key[4];
state[9] = key[5];
state[10] = key[6];
state[11] = key[7];
state[12] = get_unaligned_le32(iv + 0);
state[13] = get_unaligned_le32(iv + 4);
state[14] = get_unaligned_le32(iv + 8);
state[15] = get_unaligned_le32(iv + 12);
}
static inline void chacha_init(u32 *state, const u32 *key, const u8 *iv)
{
if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_CHACHA))
chacha_init_arch(state, key, iv);
else
chacha_init_generic(state, key, iv);
}
void chacha_crypt_arch(u32 *state, u8 *dst, const u8 *src,
unsigned int bytes, int nrounds);
void chacha_crypt_generic(u32 *state, u8 *dst, const u8 *src,
unsigned int bytes, int nrounds);
static inline void chacha_crypt(u32 *state, u8 *dst, const u8 *src,
unsigned int bytes, int nrounds)
{
if (IS_ENABLED(CONFIG_CRYPTO_ARCH_HAVE_LIB_CHACHA))
chacha_crypt_arch(state, dst, src, bytes, nrounds);
else
chacha_crypt_generic(state, dst, src, bytes, nrounds);
}
static inline void chacha20_crypt(u32 *state, u8 *dst, const u8 *src,
unsigned int bytes)
{
chacha_crypt(state, dst, src, bytes, 20);
}
#endif /* _CRYPTO_CHACHA_H */

53
include/crypto/internal/chacha.h Normal file
View file

@ -0,0 +1,53 @@
/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _CRYPTO_INTERNAL_CHACHA_H
#define _CRYPTO_INTERNAL_CHACHA_H
#include <crypto/chacha.h>
#include <crypto/internal/skcipher.h>
#include <linux/crypto.h>
struct chacha_ctx {
u32 key[8];
int nrounds;
};
void crypto_chacha_init(u32 *state, const struct chacha_ctx *ctx, const u8 *iv);
static inline int chacha_setkey(struct crypto_skcipher *tfm, const u8 *key,
unsigned int keysize, int nrounds)
{
struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
int i;
if (keysize != CHACHA_KEY_SIZE)
return -EINVAL;
for (i = 0; i < ARRAY_SIZE(ctx->key); i++)
ctx->key[i] = get_unaligned_le32(key + i * sizeof(u32));
ctx->nrounds = nrounds;
return 0;
}
static inline int chacha20_setkey(struct crypto_skcipher *tfm, const u8 *key,
unsigned int keysize)
{
return chacha_setkey(tfm, key, keysize, 20);
}
static int inline chacha12_setkey(struct crypto_skcipher *tfm, const u8 *key,
unsigned int keysize)
{
return chacha_setkey(tfm, key, keysize, 12);
}
int crypto_chacha20_setkey(struct crypto_skcipher *tfm, const u8 *key,
unsigned int keysize);
int crypto_chacha12_setkey(struct crypto_skcipher *tfm, const u8 *key,
unsigned int keysize);
int crypto_chacha_crypt(struct skcipher_request *req);
int crypto_xchacha_crypt(struct skcipher_request *req);
#endif /* _CRYPTO_CHACHA_H */

2
lib/Makefile
View file

@ -31,7 +31,7 @@ endif
lib-y := ctype.o string.o vsprintf.o cmdline.o \
rbtree.o radix-tree.o timerqueue.o\
idr.o int_sqrt.o extable.o \
sha1.o chacha.o irq_regs.o argv_split.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 \

26
lib/crypto/Kconfig
View file

@ -1,3 +1,29 @@
# SPDX-License-Identifier: GPL-2.0
comment "Crypto library routines"
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.

4
lib/crypto/Makefile
View file

@ -1 +1,5 @@
# 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

20
lib/chacha.c → lib/crypto/chacha.c
View file

@ -9,9 +9,11 @@
* (at your option) any later version.
*/
#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>
@ -76,7 +78,7 @@ 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;
@ -90,11 +92,11 @@ 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)
*
@ -103,15 +105,15 @@ 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);

35
lib/crypto/libchacha.c Normal file
View file

@ -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");