/*
* Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
*
* 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.
*/
FILE_LICENCE ( GPL2_OR_LATER );
#include <string.h>
#include <errno.h>
#include <byteswap.h>
#include <gpxe/crypto.h>
#include <gpxe/cbc.h>
#include <gpxe/aes.h>
#include "crypto/axtls/crypto.h"
/** @file
*
* AES algorithm
*
*/
/**
* 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 ):
mode = AES_MODE_128;
break;
case ( 256 / 8 ):
mode = AES_MODE_256;
break;
default:
return -EINVAL;
}
/* 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;
AES_set_key ( &aes_ctx->axtls_ctx, key, iv, mode );
aes_ctx->decrypting = 0;
return 0;
}
/**
* Set initialisation vector
*
* @v ctx Context
* @v iv Initialisation vector
*/
static void aes_setiv ( void *ctx __unused, const void *iv __unused ) {
/* Nothing to do */
}
/**
* 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;
/* 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_call_axtls ( &aes_ctx->axtls_ctx, src, dst, AES_encrypt );
}
/**
* 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;
assert ( len == AES_BLOCKSIZE );
if ( ! aes_ctx->decrypting ) {
AES_convert_key ( &aes_ctx->axtls_ctx );
aes_ctx->decrypting = 1;
}
aes_call_axtls ( &aes_ctx->axtls_ctx, src, dst, AES_decrypt );
}
/** Basic AES algorithm */
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_CIPHER ( aes_cbc, aes_cbc_algorithm,
aes_algorithm, struct aes_context, AES_BLOCKSIZE );
