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Annotation of qemu/roms/ipxe/src/crypto/axtls_aes.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (C) 2007 Michael Brown <[email protected]>.
        !             3:  *
        !             4:  * This program is free software; you can redistribute it and/or
        !             5:  * modify it under the terms of the GNU General Public License as
        !             6:  * published by the Free Software Foundation; either version 2 of the
        !             7:  * License, or any later version.
        !             8:  *
        !             9:  * This program is distributed in the hope that it will be useful, but
        !            10:  * WITHOUT ANY WARRANTY; without even the implied warranty of
        !            11:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
        !            12:  * General Public License for more details.
        !            13:  *
        !            14:  * You should have received a copy of the GNU General Public License
        !            15:  * along with this program; if not, write to the Free Software
        !            16:  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
        !            17:  */
        !            18: 
        !            19: FILE_LICENCE ( GPL2_OR_LATER );
        !            20: 
        !            21: #include <string.h>
        !            22: #include <errno.h>
        !            23: #include <byteswap.h>
        !            24: #include <ipxe/crypto.h>
        !            25: #include <ipxe/cbc.h>
        !            26: #include <ipxe/aes.h>
        !            27: #include "crypto/axtls/crypto.h"
        !            28: 
        !            29: /** @file
        !            30:  *
        !            31:  * AES algorithm
        !            32:  *
        !            33:  */
        !            34: 
        !            35: /**
        !            36:  * Set key
        !            37:  *
        !            38:  * @v ctx              Context
        !            39:  * @v key              Key
        !            40:  * @v keylen           Key length
        !            41:  * @ret rc             Return status code
        !            42:  */
        !            43: static int aes_setkey ( void *ctx, const void *key, size_t keylen ) {
        !            44:        struct aes_context *aes_ctx = ctx;
        !            45:        AES_MODE mode;
        !            46:        void *iv;
        !            47: 
        !            48:        switch ( keylen ) {
        !            49:        case ( 128 / 8 ):
        !            50:                mode = AES_MODE_128;
        !            51:                break;
        !            52:        case ( 256 / 8 ):
        !            53:                mode = AES_MODE_256;
        !            54:                break;
        !            55:        default:
        !            56:                return -EINVAL;
        !            57:        }
        !            58: 
        !            59:        /* IV is not a relevant concept at this stage; use a dummy
        !            60:         * value that will have no side-effects.
        !            61:         */
        !            62:        iv = &aes_ctx->axtls_ctx.iv;
        !            63: 
        !            64:        AES_set_key ( &aes_ctx->axtls_ctx, key, iv, mode );
        !            65: 
        !            66:        aes_ctx->decrypting = 0;
        !            67: 
        !            68:        return 0;
        !            69: }
        !            70: 
        !            71: /**
        !            72:  * Set initialisation vector
        !            73:  *
        !            74:  * @v ctx              Context
        !            75:  * @v iv               Initialisation vector
        !            76:  */
        !            77: static void aes_setiv ( void *ctx __unused, const void *iv __unused ) {
        !            78:        /* Nothing to do */
        !            79: }
        !            80: 
        !            81: /**
        !            82:  * Call AXTLS' AES_encrypt() or AES_decrypt() functions
        !            83:  *
        !            84:  * @v axtls_ctx                AXTLS AES context
        !            85:  * @v src              Data to process
        !            86:  * @v dst              Buffer for output
        !            87:  * @v func             AXTLS AES function to call
        !            88:  */
        !            89: static void aes_call_axtls ( AES_CTX *axtls_ctx, const void *src, void *dst,
        !            90:                             void ( * func ) ( const AES_CTX *axtls_ctx,
        !            91:                                               uint32_t *data ) ){
        !            92:        const uint32_t *srcl = src;
        !            93:        uint32_t *dstl = dst;
        !            94:        unsigned int i;
        !            95: 
        !            96:        /* AXTLS' AES_encrypt() and AES_decrypt() functions both
        !            97:         * expect to deal with an array of four dwords in host-endian
        !            98:         * order.
        !            99:         */
        !           100:        for ( i = 0 ; i < 4 ; i++ )
        !           101:                dstl[i] = ntohl ( srcl[i] );
        !           102:        func ( axtls_ctx, dstl );
        !           103:        for ( i = 0 ; i < 4 ; i++ )
        !           104:                dstl[i] = htonl ( dstl[i] );
        !           105: }
        !           106: 
        !           107: /**
        !           108:  * Encrypt data
        !           109:  *
        !           110:  * @v ctx              Context
        !           111:  * @v src              Data to encrypt
        !           112:  * @v dst              Buffer for encrypted data
        !           113:  * @v len              Length of data
        !           114:  */
        !           115: static void aes_encrypt ( void *ctx, const void *src, void *dst,
        !           116:                          size_t len ) {
        !           117:        struct aes_context *aes_ctx = ctx;
        !           118: 
        !           119:        assert ( len == AES_BLOCKSIZE );
        !           120:        if ( aes_ctx->decrypting )
        !           121:                assert ( 0 );
        !           122:        aes_call_axtls ( &aes_ctx->axtls_ctx, src, dst, AES_encrypt );
        !           123: }
        !           124: 
        !           125: /**
        !           126:  * Decrypt data
        !           127:  *
        !           128:  * @v ctx              Context
        !           129:  * @v src              Data to decrypt
        !           130:  * @v dst              Buffer for decrypted data
        !           131:  * @v len              Length of data
        !           132:  */
        !           133: static void aes_decrypt ( void *ctx, const void *src, void *dst,
        !           134:                          size_t len ) {
        !           135:        struct aes_context *aes_ctx = ctx;
        !           136: 
        !           137:        assert ( len == AES_BLOCKSIZE );
        !           138:        if ( ! aes_ctx->decrypting ) {
        !           139:                AES_convert_key ( &aes_ctx->axtls_ctx );
        !           140:                aes_ctx->decrypting = 1;
        !           141:        }
        !           142:        aes_call_axtls ( &aes_ctx->axtls_ctx, src, dst, AES_decrypt );
        !           143: }
        !           144: 
        !           145: /** Basic AES algorithm */
        !           146: struct cipher_algorithm aes_algorithm = {
        !           147:        .name = "aes",
        !           148:        .ctxsize = sizeof ( struct aes_context ),
        !           149:        .blocksize = AES_BLOCKSIZE,
        !           150:        .setkey = aes_setkey,
        !           151:        .setiv = aes_setiv,
        !           152:        .encrypt = aes_encrypt,
        !           153:        .decrypt = aes_decrypt,
        !           154: };
        !           155: 
        !           156: /* AES with cipher-block chaining */
        !           157: CBC_CIPHER ( aes_cbc, aes_cbc_algorithm,
        !           158:             aes_algorithm, struct aes_context, AES_BLOCKSIZE );

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