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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as well, in a way that permits the implementation to be superseded by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>
This commit is contained in:
Ard Biesheuvel
2019-11-08 13:22:08 +01:00
committed by Herbert Xu
parent 746b2e024c
commit 5fb8ef2580
12 changed files with 199 additions and 86 deletions
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53
include/crypto/internal/chacha.h Normal file
View File

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/* 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 */