159 lines
3.7 KiB
C
159 lines
3.7 KiB
C
/*
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* Copyright (C) 2007 Michael Brown <mbrown@fensystems.co.uk>.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of the
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* License, or any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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FILE_LICENCE ( GPL2_OR_LATER );
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#include <string.h>
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#include <errno.h>
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#include <byteswap.h>
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#include <ipxe/crypto.h>
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#include <ipxe/cbc.h>
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#include <ipxe/aes.h>
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#include "crypto/axtls/crypto.h"
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/** @file
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*
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* AES algorithm
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*
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*/
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/**
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* Set key
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*
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* @v ctx Context
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* @v key Key
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* @v keylen Key length
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* @ret rc Return status code
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*/
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static int aes_setkey ( void *ctx, const void *key, size_t keylen ) {
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struct aes_context *aes_ctx = ctx;
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AES_MODE mode;
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void *iv;
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switch ( keylen ) {
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case ( 128 / 8 ):
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mode = AES_MODE_128;
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break;
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case ( 256 / 8 ):
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mode = AES_MODE_256;
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break;
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default:
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return -EINVAL;
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}
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/* IV is not a relevant concept at this stage; use a dummy
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* value that will have no side-effects.
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*/
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iv = &aes_ctx->axtls_ctx.iv;
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AES_set_key ( &aes_ctx->axtls_ctx, key, iv, mode );
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aes_ctx->decrypting = 0;
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return 0;
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}
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/**
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* Set initialisation vector
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*
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* @v ctx Context
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* @v iv Initialisation vector
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*/
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static void aes_setiv ( void *ctx __unused, const void *iv __unused ) {
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/* Nothing to do */
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}
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/**
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* Call AXTLS' AES_encrypt() or AES_decrypt() functions
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*
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* @v axtls_ctx AXTLS AES context
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* @v src Data to process
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* @v dst Buffer for output
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* @v func AXTLS AES function to call
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*/
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static void aes_call_axtls ( AES_CTX *axtls_ctx, const void *src, void *dst,
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void ( * func ) ( const AES_CTX *axtls_ctx,
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uint32_t *data ) ){
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const uint32_t *srcl = src;
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uint32_t *dstl = dst;
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unsigned int i;
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/* AXTLS' AES_encrypt() and AES_decrypt() functions both
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* expect to deal with an array of four dwords in host-endian
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* order.
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*/
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for ( i = 0 ; i < 4 ; i++ )
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dstl[i] = ntohl ( srcl[i] );
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func ( axtls_ctx, dstl );
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for ( i = 0 ; i < 4 ; i++ )
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dstl[i] = htonl ( dstl[i] );
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}
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/**
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* Encrypt data
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*
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* @v ctx Context
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* @v src Data to encrypt
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* @v dst Buffer for encrypted data
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* @v len Length of data
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*/
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static void aes_encrypt ( void *ctx, const void *src, void *dst,
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size_t len ) {
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struct aes_context *aes_ctx = ctx;
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assert ( len == AES_BLOCKSIZE );
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if ( aes_ctx->decrypting )
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assert ( 0 );
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aes_call_axtls ( &aes_ctx->axtls_ctx, src, dst, AES_encrypt );
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}
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/**
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* Decrypt data
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*
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* @v ctx Context
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* @v src Data to decrypt
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* @v dst Buffer for decrypted data
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* @v len Length of data
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*/
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static void aes_decrypt ( void *ctx, const void *src, void *dst,
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size_t len ) {
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struct aes_context *aes_ctx = ctx;
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assert ( len == AES_BLOCKSIZE );
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if ( ! aes_ctx->decrypting ) {
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AES_convert_key ( &aes_ctx->axtls_ctx );
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aes_ctx->decrypting = 1;
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}
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aes_call_axtls ( &aes_ctx->axtls_ctx, src, dst, AES_decrypt );
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}
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/** Basic AES algorithm */
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struct cipher_algorithm aes_algorithm = {
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.name = "aes",
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.ctxsize = sizeof ( struct aes_context ),
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.blocksize = AES_BLOCKSIZE,
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.setkey = aes_setkey,
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.setiv = aes_setiv,
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.encrypt = aes_encrypt,
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.decrypt = aes_decrypt,
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};
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/* AES with cipher-block chaining */
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CBC_CIPHER ( aes_cbc, aes_cbc_algorithm,
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aes_algorithm, struct aes_context, AES_BLOCKSIZE );
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