From 5fb8ef25803ef33e2eb60b626435828b937bed75 Mon Sep 17 00:00:00 2001 From: Ard Biesheuvel Date: Fri, 8 Nov 2019 13:22:08 +0100 Subject: 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API, let's expose the streamcipher bits via a library API as well, in a way that permits the implementation to be superseded by an architecture specific one if provided.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 Signed-off-by: Herbert Xu --- include/crypto/chacha.h | 77 ++++++++++++++++++++++++++++++++++++++----------- 1 file changed, 60 insertions(+), 17 deletions(-) (limited to 'include/crypto/chacha.h') diff --git a/include/crypto/chacha.h b/include/crypto/chacha.h index d1e723c6a37d..5c662f8fecac 100644 --- a/include/crypto/chacha.h +++ b/include/crypto/chacha.h @@ -15,9 +15,8 @@ #ifndef _CRYPTO_CHACHA_H #define _CRYPTO_CHACHA_H -#include +#include #include -#include /* 32-bit stream position, then 96-bit nonce (RFC7539 convention) */ #define CHACHA_IV_SIZE 16 @@ -29,26 +28,70 @@ /* 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); + +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_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); +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); +} -int crypto_chacha_crypt(struct skcipher_request *req); -int crypto_xchacha_crypt(struct skcipher_request *req); +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 */ -- cgit v1.2.3