diff --git a/src/crypto/axtls/aes.c b/src/crypto/axtls/aes.c index 9154a515..0c0d7247 100644 --- a/src/crypto/axtls/aes.c +++ b/src/crypto/axtls/aes.c @@ -152,10 +152,6 @@ static const unsigned char Rcon[30]= 0xb3,0x7d,0xfa,0xef,0xc5,0x91, }; -/* ----- static functions ----- */ -static void AES_encrypt(const AES_CTX *ctx, uint32_t *data); -static void AES_decrypt(const AES_CTX *ctx, uint32_t *data); - /* Perform doubling in Galois Field GF(2^8) using the irreducible polynomial x^8+x^4+x^3+x+1 */ static unsigned char AES_xtime(uint32_t x) @@ -257,6 +253,7 @@ void AES_convert_key(AES_CTX *ctx) } } +#if 0 /** * Encrypt a byte sequence (with a block size 16) using the AES cipher. */ @@ -358,11 +355,12 @@ void AES_cbc_decrypt(AES_CTX *ctx, const uint8_t *msg, uint8_t *out, int length) l2n(xor2, iv); l2n(xor3, iv); } +#endif /** * Encrypt a single block (16 bytes) of data */ -static void AES_encrypt(const AES_CTX *ctx, uint32_t *data) +void AES_encrypt(const AES_CTX *ctx, uint32_t *data) { /* To make this code smaller, generate the sbox entries on the fly. * This will have a really heavy effect upon performance. @@ -418,7 +416,7 @@ static void AES_encrypt(const AES_CTX *ctx, uint32_t *data) /** * Decrypt a single block (16 bytes) of data */ -static void AES_decrypt(const AES_CTX *ctx, uint32_t *data) +void AES_decrypt(const AES_CTX *ctx, uint32_t *data) { uint32_t tmp[4]; uint32_t xt0,xt1,xt2,xt3,xt4,xt5,xt6; diff --git a/src/crypto/axtls/crypto.h b/src/crypto/axtls/crypto.h index de1dbeb4..12acb27f 100644 --- a/src/crypto/axtls/crypto.h +++ b/src/crypto/axtls/crypto.h @@ -55,6 +55,8 @@ void AES_cbc_encrypt(AES_CTX *ctx, const uint8_t *msg, uint8_t *out, int length); void AES_cbc_decrypt(AES_CTX *ks, const uint8_t *in, uint8_t *out, int length); void AES_convert_key(AES_CTX *ctx); +void AES_encrypt(const AES_CTX *ctx, uint32_t *data); +void AES_decrypt(const AES_CTX *ctx, uint32_t *data); /************************************************************************** * RC4 declarations diff --git a/src/crypto/axtls_aes.c b/src/crypto/axtls_aes.c index a19ad3c4..04d274d3 100644 --- a/src/crypto/axtls_aes.c +++ b/src/crypto/axtls_aes.c @@ -1,17 +1,65 @@ -#include "crypto/axtls/crypto.h" +/* + * Copyright (C) 2007 Michael Brown . + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of the + * License, or any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + #include #include +#include #include +#include #include +#include "crypto/axtls/crypto.h" -struct aes_cbc_context { - AES_CTX ctx; +/** @file + * + * AES algorithm + * + */ + +/** Basic AES blocksize */ +#define AES_BLOCKSIZE 16 + +/**************************************************************************** + * + * Basic AES algorithm (independent of mode of operation) + * + **************************************************************************** + */ + +/** AES context */ +struct aes_context { + /** AES context for AXTLS */ + AES_CTX axtls_ctx; + /** Cipher is being used for decrypting */ int decrypting; }; -static int aes_cbc_setkey ( void *ctx, const void *key, size_t keylen ) { - struct aes_cbc_context *aesctx = ctx; +/** + * Set key + * + * @v ctx Context + * @v key Key + * @v keylen Key length + * @ret rc Return status code + */ +static int aes_setkey ( void *ctx, const void *key, size_t keylen ) { + struct aes_context *aes_ctx = ctx; AES_MODE mode; + void *iv; switch ( keylen ) { case ( 128 / 8 ): @@ -24,45 +72,182 @@ static int aes_cbc_setkey ( void *ctx, const void *key, size_t keylen ) { return -EINVAL; } - AES_set_key ( &aesctx->ctx, key, aesctx->ctx.iv, mode ); + /* IV is not a relevant concept at this stage; use a dummy + * value that will have no side-effects. + */ + iv = &aes_ctx->axtls_ctx.iv; - aesctx->decrypting = 0; + AES_set_key ( &aes_ctx->axtls_ctx, key, iv, mode ); + + aes_ctx->decrypting = 0; return 0; } -static void aes_cbc_setiv ( void *ctx, const void *iv ) { - struct aes_cbc_context *aesctx = ctx; - - memcpy ( aesctx->ctx.iv, iv, sizeof ( aesctx->ctx.iv ) ); +/** + * Set initialisation vector + * + * @v ctx Context + * @v iv Initialisation vector + */ +static void aes_setiv ( void *ctx __unused, const void *iv __unused ) { + /* Nothing to do */ } -static void aes_cbc_encrypt ( void *ctx, const void *data, void *dst, - size_t len ) { - struct aes_cbc_context *aesctx = ctx; +/** + * Call AXTLS' AES_encrypt() or AES_decrypt() functions + * + * @v axtls_ctx AXTLS AES context + * @v src Data to process + * @v dst Buffer for output + * @v func AXTLS AES function to call + */ +static void aes_call_axtls ( AES_CTX *axtls_ctx, const void *src, void *dst, + void ( * func ) ( const AES_CTX *axtls_ctx, + uint32_t *data ) ){ + const uint32_t *srcl = src; + uint32_t *dstl = dst; + unsigned int i; - if ( aesctx->decrypting ) + /* AXTLS' AES_encrypt() and AES_decrypt() functions both + * expect to deal with an array of four dwords in host-endian + * order. + */ + for ( i = 0 ; i < 4 ; i++ ) + dstl[i] = ntohl ( srcl[i] ); + func ( axtls_ctx, dstl ); + for ( i = 0 ; i < 4 ; i++ ) + dstl[i] = htonl ( dstl[i] ); +} + +/** + * Encrypt data + * + * @v ctx Context + * @v src Data to encrypt + * @v dst Buffer for encrypted data + * @v len Length of data + */ +static void aes_encrypt ( void *ctx, const void *src, void *dst, + size_t len ) { + struct aes_context *aes_ctx = ctx; + + assert ( len == AES_BLOCKSIZE ); + if ( aes_ctx->decrypting ) assert ( 0 ); - - AES_cbc_encrypt ( &aesctx->ctx, data, dst, len ); + aes_call_axtls ( &aes_ctx->axtls_ctx, src, dst, AES_encrypt ); } -static void aes_cbc_decrypt ( void *ctx, const void *data, void *dst, - size_t len ) { - struct aes_cbc_context *aesctx = 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_decrypt ( void *ctx, const void *src, void *dst, + size_t len ) { + struct aes_context *aes_ctx = ctx; - if ( ! aesctx->decrypting ) { - AES_convert_key ( &aesctx->ctx ); - aesctx->decrypting = 1; + assert ( len == AES_BLOCKSIZE ); + if ( ! aes_ctx->decrypting ) { + AES_convert_key ( &aes_ctx->axtls_ctx ); + aes_ctx->decrypting = 1; } - - AES_cbc_decrypt ( &aesctx->ctx, data, dst, len ); + aes_call_axtls ( &aes_ctx->axtls_ctx, src, dst, AES_decrypt ); } +/** Basic AES algorithm */ +static struct cipher_algorithm aes_algorithm = { + .name = "aes", + .ctxsize = sizeof ( struct aes_context ), + .blocksize = AES_BLOCKSIZE, + .setkey = aes_setkey, + .setiv = aes_setiv, + .encrypt = aes_encrypt, + .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 = 16, + .blocksize = AES_BLOCKSIZE, .setkey = aes_cbc_setkey, .setiv = aes_cbc_setiv, .encrypt = aes_cbc_encrypt, diff --git a/src/crypto/cbc.c b/src/crypto/cbc.c new file mode 100644 index 00000000..a25d826e --- /dev/null +++ b/src/crypto/cbc.c @@ -0,0 +1,99 @@ +/* + * Copyright (C) 2009 Michael Brown . + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of the + * License, or any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#include +#include +#include +#include + +/** @file + * + * Cipher-block chaining + * + */ + +/** + * XOR data blocks + * + * @v src Input data + * @v dst Second input data and output data buffer + * @v len Length of data + */ +static void cbc_xor ( const void *src, void *dst, size_t len ) { + const uint32_t *srcl = src; + uint32_t *dstl = dst; + unsigned int i; + + /* Assume that block sizes will always be dword-aligned, for speed */ + assert ( ( len % sizeof ( *srcl ) ) == 0 ); + + for ( i = 0 ; i < ( len / sizeof ( *srcl ) ) ; i++ ) + dstl[i] ^= srcl[i]; +} + +/** + * Encrypt data + * + * @v ctx Context + * @v src Data to encrypt + * @v dst Buffer for encrypted data + * @v len Length of data + * @v 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; + + assert ( ( len % blocksize ) == 0 ); + + while ( len ) { + cbc_xor ( src, cbc_ctx, blocksize ); + cipher_encrypt ( cipher, ctx, cbc_ctx, dst, blocksize ); + memcpy ( cbc_ctx, dst, blocksize ); + dst += blocksize; + src += blocksize; + len -= blocksize; + } +} + +/** + * Decrypt data + * + * @v ctx Context + * @v src Data to decrypt + * @v dst Buffer for decrypted data + * @v len Length of data + * @v 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; + + assert ( ( len % blocksize ) == 0 ); + + while ( len ) { + cipher_decrypt ( cipher, ctx, src, dst, blocksize ); + cbc_xor ( cbc_ctx, dst, blocksize ); + memcpy ( cbc_ctx, src, blocksize ); + dst += blocksize; + src += blocksize; + len -= blocksize; + } +} diff --git a/src/include/gpxe/cbc.h b/src/include/gpxe/cbc.h new file mode 100644 index 00000000..e2d57764 --- /dev/null +++ b/src/include/gpxe/cbc.h @@ -0,0 +1,50 @@ +#ifndef _GPXE_CBC_H +#define _GPXE_CBC_H + +/** @file + * + * Cipher-block chaining + * + */ + +#include + +/** + * Set key + * + * @v ctx Context + * @v key Key + * @v keylen Key length + * @v 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, + void *cbc_ctx __unused ) { + + return cipher_setkey ( cipher, ctx, key, keylen ); +} + +/** + * Set initialisation vector + * + * @v ctx Context + * @v iv Initialisation vector + * @v cipher Underlying cipher algorithm + * @v cbc_ctx CBC context + */ +static inline void cbc_setiv ( void *ctx __unused, const void *iv, + struct cipher_algorithm *cipher, + void *cbc_ctx ) { + memcpy ( cbc_ctx, iv, cipher->blocksize ); +} + +extern void cbc_encrypt ( void *ctx, const void *src, void *dst, + size_t len, struct cipher_algorithm *cipher, + void *cbc_ctx ); +extern void cbc_decrypt ( void *ctx, const void *src, void *dst, + size_t len, struct cipher_algorithm *cipher, + void *cbc_ctx ); + +#endif /* _GPXE_CBC_H */