From 9937bf13c961bb452e3e41a8fb28694af2b73c46 Mon Sep 17 00:00:00 2001 From: Michael Brown Date: Thu, 19 Feb 2009 01:48:52 +0000 Subject: [PATCH] [crypto] Allow creation of arbitrary CBC cipher algorithms using CBC_CIPHER() Given any block cipher, a corresponding CBC mode of behaviour for the cipher can be created using the CBC_CIPHER() macro. --- src/crypto/axtls_aes.c | 92 +----------------------------------------- src/crypto/cbc.c | 16 ++++---- src/include/gpxe/cbc.h | 64 +++++++++++++++++++++++++---- 3 files changed, 66 insertions(+), 106 deletions(-) diff --git a/src/crypto/axtls_aes.c b/src/crypto/axtls_aes.c index 04d274d3..51e1924e 100644 --- a/src/crypto/axtls_aes.c +++ b/src/crypto/axtls_aes.c @@ -33,13 +33,6 @@ /** Basic AES blocksize */ #define AES_BLOCKSIZE 16 -/**************************************************************************** - * - * Basic AES algorithm (independent of mode of operation) - * - **************************************************************************** - */ - /** AES context */ struct aes_context { /** AES context for AXTLS */ @@ -169,87 +162,6 @@ static struct cipher_algorithm aes_algorithm = { .decrypt = aes_decrypt, }; -/**************************************************************************** - * - * AES with cipher-block chaining (CBC) - * - **************************************************************************** - */ - -/** AES with CBC context */ -struct aes_cbc_context { - /** AES context */ - struct aes_context aes_ctx; - /** CBC context */ - uint8_t cbc_ctx[AES_BLOCKSIZE]; -}; - -/** - * Set key - * - * @v ctx Context - * @v key Key - * @v keylen Key length - * @ret rc Return status code - */ -static int aes_cbc_setkey ( void *ctx, const void *key, size_t keylen ) { - struct aes_cbc_context *aes_cbc_ctx = ctx; - - return cbc_setkey ( ctx, key, keylen, &aes_algorithm, - &aes_cbc_ctx->cbc_ctx ); -} - -/** - * Set initialisation vector - * - * @v ctx Context - * @v iv Initialisation vector - */ -static void aes_cbc_setiv ( void *ctx, const void *iv ) { - struct aes_cbc_context *aes_cbc_ctx = ctx; - - cbc_setiv ( ctx, iv, &aes_algorithm, &aes_cbc_ctx->cbc_ctx ); -} - -/** - * Encrypt data - * - * @v ctx Context - * @v src Data to encrypt - * @v dst Buffer for encrypted data - * @v len Length of data - */ -static void aes_cbc_encrypt ( void *ctx, const void *src, void *dst, - size_t len ) { - struct aes_cbc_context *aes_cbc_ctx = ctx; - - cbc_encrypt ( &aes_cbc_ctx->aes_ctx, src, dst, len, - &aes_algorithm, &aes_cbc_ctx->cbc_ctx ); -} - -/** - * Decrypt data - * - * @v ctx Context - * @v src Data to decrypt - * @v dst Buffer for decrypted data - * @v len Length of data - */ -static void aes_cbc_decrypt ( void *ctx, const void *src, void *dst, - size_t len ) { - struct aes_cbc_context *aes_cbc_ctx = ctx; - - cbc_decrypt ( &aes_cbc_ctx->aes_ctx, src, dst, len, - &aes_algorithm, &aes_cbc_ctx->cbc_ctx ); -} - /* AES with cipher-block chaining */ -struct cipher_algorithm aes_cbc_algorithm = { - .name = "aes_cbc", - .ctxsize = sizeof ( struct aes_cbc_context ), - .blocksize = AES_BLOCKSIZE, - .setkey = aes_cbc_setkey, - .setiv = aes_cbc_setiv, - .encrypt = aes_cbc_encrypt, - .decrypt = aes_cbc_decrypt, -}; +CBC_CIPHER ( aes_cbc, aes_cbc_algorithm, + aes_algorithm, struct aes_context, AES_BLOCKSIZE ); diff --git a/src/crypto/cbc.c b/src/crypto/cbc.c index a25d826e..c7116ea9 100644 --- a/src/crypto/cbc.c +++ b/src/crypto/cbc.c @@ -53,18 +53,18 @@ static void cbc_xor ( const void *src, void *dst, size_t len ) { * @v src Data to encrypt * @v dst Buffer for encrypted data * @v len Length of data - * @v cipher Underlying cipher algorithm + * @v raw_cipher Underlying cipher algorithm * @v cbc_ctx CBC context */ void cbc_encrypt ( void *ctx, const void *src, void *dst, size_t len, - struct cipher_algorithm *cipher, void *cbc_ctx ) { - size_t blocksize = cipher->blocksize; + struct cipher_algorithm *raw_cipher, void *cbc_ctx ) { + size_t blocksize = raw_cipher->blocksize; assert ( ( len % blocksize ) == 0 ); while ( len ) { cbc_xor ( src, cbc_ctx, blocksize ); - cipher_encrypt ( cipher, ctx, cbc_ctx, dst, blocksize ); + cipher_encrypt ( raw_cipher, ctx, cbc_ctx, dst, blocksize ); memcpy ( cbc_ctx, dst, blocksize ); dst += blocksize; src += blocksize; @@ -79,17 +79,17 @@ void cbc_encrypt ( void *ctx, const void *src, void *dst, size_t len, * @v src Data to decrypt * @v dst Buffer for decrypted data * @v len Length of data - * @v cipher Underlying cipher algorithm + * @v raw_cipher Underlying cipher algorithm * @v cbc_ctx CBC context */ void cbc_decrypt ( void *ctx, const void *src, void *dst, size_t len, - struct cipher_algorithm *cipher, void *cbc_ctx ) { - size_t blocksize = cipher->blocksize; + struct cipher_algorithm *raw_cipher, void *cbc_ctx ) { + size_t blocksize = raw_cipher->blocksize; assert ( ( len % blocksize ) == 0 ); while ( len ) { - cipher_decrypt ( cipher, ctx, src, dst, blocksize ); + cipher_decrypt ( raw_cipher, ctx, src, dst, blocksize ); cbc_xor ( cbc_ctx, dst, blocksize ); memcpy ( cbc_ctx, src, blocksize ); dst += blocksize; diff --git a/src/include/gpxe/cbc.h b/src/include/gpxe/cbc.h index e2d57764..fcc115eb 100644 --- a/src/include/gpxe/cbc.h +++ b/src/include/gpxe/cbc.h @@ -15,15 +15,15 @@ * @v ctx Context * @v key Key * @v keylen Key length - * @v cipher Underlying cipher algorithm + * @v raw_cipher Underlying cipher algorithm * @v cbc_ctx CBC context * @ret rc Return status code */ static inline int cbc_setkey ( void *ctx, const void *key, size_t keylen, - struct cipher_algorithm *cipher, + struct cipher_algorithm *raw_cipher, void *cbc_ctx __unused ) { - return cipher_setkey ( cipher, ctx, key, keylen ); + return cipher_setkey ( raw_cipher, ctx, key, keylen ); } /** @@ -31,20 +31,68 @@ static inline int cbc_setkey ( void *ctx, const void *key, size_t keylen, * * @v ctx Context * @v iv Initialisation vector - * @v cipher Underlying cipher algorithm + * @v raw_cipher Underlying cipher algorithm * @v cbc_ctx CBC context */ static inline void cbc_setiv ( void *ctx __unused, const void *iv, - struct cipher_algorithm *cipher, + struct cipher_algorithm *raw_cipher, void *cbc_ctx ) { - memcpy ( cbc_ctx, iv, cipher->blocksize ); + memcpy ( cbc_ctx, iv, raw_cipher->blocksize ); } extern void cbc_encrypt ( void *ctx, const void *src, void *dst, - size_t len, struct cipher_algorithm *cipher, + size_t len, struct cipher_algorithm *raw_cipher, void *cbc_ctx ); extern void cbc_decrypt ( void *ctx, const void *src, void *dst, - size_t len, struct cipher_algorithm *cipher, + size_t len, struct cipher_algorithm *raw_cipher, void *cbc_ctx ); +/** + * Create a cipher-block chaining mode of behaviour of an existing cipher + * + * @v _cbc_name Name for the new CBC cipher + * @v _cbc_cipher New cipher algorithm + * @v _raw_cipher Underlying cipher algorithm + * @v _raw_context Context structure for the underlying cipher + * @v _blocksize Cipher block size + */ +#define CBC_CIPHER( _cbc_name, _cbc_cipher, _raw_cipher, _raw_context, \ + _blocksize ) \ +struct _cbc_name ## _context { \ + _raw_context raw_ctx; \ + uint8_t cbc_ctx[_blocksize]; \ +}; \ +static int _cbc_name ## _setkey ( void *ctx, const void *key, \ + size_t keylen ) { \ + struct _cbc_name ## _context * _cbc_name ## _ctx = ctx; \ + return cbc_setkey ( &_cbc_name ## _ctx->raw_ctx, key, keylen, \ + &_raw_cipher, &_cbc_name ## _ctx->cbc_ctx );\ +} \ +static void _cbc_name ## _setiv ( void *ctx, const void *iv ) { \ + struct _cbc_name ## _context * _cbc_name ## _ctx = ctx; \ + cbc_setiv ( &_cbc_name ## _ctx->raw_ctx, iv, \ + &_raw_cipher, &aes_cbc_ctx->cbc_ctx ); \ +} \ +static void _cbc_name ## _encrypt ( void *ctx, const void *src, \ + void *dst, size_t len ) { \ + struct _cbc_name ## _context * _cbc_name ## _ctx = ctx; \ + cbc_encrypt ( &_cbc_name ## _ctx->raw_ctx, src, dst, len, \ + &_raw_cipher, &aes_cbc_ctx->cbc_ctx ); \ +} \ +static void _cbc_name ## _decrypt ( void *ctx, const void *src, \ + void *dst, size_t len ) { \ + struct _cbc_name ## _context * _cbc_name ## _ctx = ctx; \ + cbc_decrypt ( &_cbc_name ## _ctx->raw_ctx, src, dst, len, \ + &_raw_cipher, &aes_cbc_ctx->cbc_ctx ); \ +} \ +struct cipher_algorithm _cbc_cipher = { \ + .name = #_cbc_name, \ + .ctxsize = sizeof ( struct _cbc_name ## _context ), \ + .blocksize = _blocksize, \ + .setkey = _cbc_name ## _setkey, \ + .setiv = _cbc_name ## _setiv, \ + .encrypt = _cbc_name ## _encrypt, \ + .decrypt = _cbc_name ## _decrypt, \ +}; + #endif /* _GPXE_CBC_H */