| /* |
| * 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 ); |