/**
 * \file mbedtls_md.c
 *
 * \brief Generic message digest wrapper for mbed TLS
 *
 * \author Adriaan de Jong <dejong@fox-it.com>
 *
 *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
 *  Copyright (C) 2018, Intel Corporation, All Rights Reserved.
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  This file is part of mbed TLS (https://tls.mbed.org)
 */

#include <hypervisor.h>
#include "md.h"
#include "md_internal.h"

/*
 * Reminder: update profiles in x509_crt.c when adding a new hash!
 */
static const int supported_digests[] = {
        MBEDTLS_MD_SHA256,
        MBEDTLS_MD_NONE
};

const int *mbedtls_md_list( void )
{
    return( supported_digests );
}

const mbedtls_md_info_t *mbedtls_md_info_from_type( mbedtls_md_type_t md_type )
{
    switch( md_type )
    {
        case MBEDTLS_MD_SHA256:
            return( &mbedtls_sha256_info );
        default:
            return( NULL );
    }
}

void mbedtls_md_init( mbedtls_md_context_t *ctx )
{
    memset( ctx, 0, sizeof( mbedtls_md_context_t ) );
}

void mbedtls_md_free( mbedtls_md_context_t *ctx )
{
    if( ctx == NULL || ctx->md_info == NULL )
        return;

    if( ctx->md_ctx != NULL )
        ctx->md_info->ctx_free_func( ctx->md_ctx );

    if( ctx->hmac_ctx != NULL )
    {
        mbedtls_platform_zeroize( ctx->hmac_ctx,
                                  2 * ctx->md_info->block_size );
        mbedtls_free( ctx->hmac_ctx );
    }

    mbedtls_platform_zeroize( ctx, sizeof( mbedtls_md_context_t ) );
}

int mbedtls_md_clone( mbedtls_md_context_t *dst,
                      const mbedtls_md_context_t *src )
{
    if( dst == NULL || dst->md_info == NULL ||
        src == NULL || src->md_info == NULL ||
        dst->md_info != src->md_info )
    {
        return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );
    }

    dst->md_info->clone_func( dst->md_ctx, src->md_ctx );

    return( 0 );
}

int mbedtls_md_setup( mbedtls_md_context_t *ctx, const mbedtls_md_info_t *md_info, int hmac )
{
    if( md_info == NULL || ctx == NULL )
        return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );

    if( ( ctx->md_ctx = md_info->ctx_alloc_func() ) == NULL )
        return( MBEDTLS_ERR_MD_ALLOC_FAILED );

    if( hmac != 0 )
    {
        ctx->hmac_ctx = mbedtls_calloc( 2, md_info->block_size );
        if( ctx->hmac_ctx == NULL )
        {
            md_info->ctx_free_func( ctx->md_ctx );
            return( MBEDTLS_ERR_MD_ALLOC_FAILED );
        }
    }

    ctx->md_info = md_info;

    return( 0 );
}

int mbedtls_md_starts( mbedtls_md_context_t *ctx )
{
    if( ctx == NULL || ctx->md_info == NULL )
        return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );

    return( ctx->md_info->starts_func( ctx->md_ctx ) );
}

int mbedtls_md_update( mbedtls_md_context_t *ctx, const unsigned char *input, size_t ilen )
{
    if( ctx == NULL || ctx->md_info == NULL )
        return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );

    return( ctx->md_info->update_func( ctx->md_ctx, input, ilen ) );
}

int mbedtls_md_finish( mbedtls_md_context_t *ctx, unsigned char *output )
{
    if( ctx == NULL || ctx->md_info == NULL )
        return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );

    return( ctx->md_info->finish_func( ctx->md_ctx, output ) );
}

int mbedtls_md( const mbedtls_md_info_t *md_info, const unsigned char *input, size_t ilen,
            unsigned char *output )
{
    if( md_info == NULL )
        return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );

    return( md_info->digest_func( input, ilen, output ) );
}

int mbedtls_md_hmac_starts( mbedtls_md_context_t *ctx, const unsigned char *key, size_t keylen )
{
    int ret;
    unsigned char sum[MBEDTLS_MD_MAX_SIZE];
    unsigned char *ipad, *opad;
    size_t i;

    if( ctx == NULL || ctx->md_info == NULL || ctx->hmac_ctx == NULL )
        return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );

    if( keylen > (size_t) ctx->md_info->block_size )
    {
        if( ( ret = ctx->md_info->starts_func( ctx->md_ctx ) ) != 0 )
            goto cleanup;
        if( ( ret = ctx->md_info->update_func( ctx->md_ctx, key, keylen ) ) != 0 )
            goto cleanup;
        if( ( ret = ctx->md_info->finish_func( ctx->md_ctx, sum ) ) != 0 )
            goto cleanup;

        keylen = ctx->md_info->size;
        key = sum;
    }

    ipad = (unsigned char *) ctx->hmac_ctx;
    opad = (unsigned char *) ctx->hmac_ctx + ctx->md_info->block_size;

    memset( ipad, 0x36, ctx->md_info->block_size );
    memset( opad, 0x5C, ctx->md_info->block_size );

    for( i = 0; i < keylen; i++ )
    {
        ipad[i] = (unsigned char)( ipad[i] ^ key[i] );
        opad[i] = (unsigned char)( opad[i] ^ key[i] );
    }

    if( ( ret = ctx->md_info->starts_func( ctx->md_ctx ) ) != 0 )
        goto cleanup;
    if( ( ret = ctx->md_info->update_func( ctx->md_ctx, ipad,
                                           ctx->md_info->block_size ) ) != 0 )
        goto cleanup;

cleanup:
    mbedtls_platform_zeroize( sum, sizeof( sum ) );

    return( ret );
}

int mbedtls_md_hmac_update( mbedtls_md_context_t *ctx, const unsigned char *input, size_t ilen )
{
    if( ctx == NULL || ctx->md_info == NULL || ctx->hmac_ctx == NULL )
        return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );

    return( ctx->md_info->update_func( ctx->md_ctx, input, ilen ) );
}

int mbedtls_md_hmac_finish( mbedtls_md_context_t *ctx, unsigned char *output )
{
    int ret;
    unsigned char tmp[MBEDTLS_MD_MAX_SIZE];
    unsigned char *opad;

    if( ctx == NULL || ctx->md_info == NULL || ctx->hmac_ctx == NULL )
        return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );

    opad = (unsigned char *) ctx->hmac_ctx + ctx->md_info->block_size;

    if( ( ret = ctx->md_info->finish_func( ctx->md_ctx, tmp ) ) != 0 )
        return( ret );
    if( ( ret = ctx->md_info->starts_func( ctx->md_ctx ) ) != 0 )
        return( ret );
    if( ( ret = ctx->md_info->update_func( ctx->md_ctx, opad,
                                           ctx->md_info->block_size ) ) != 0 )
        return( ret );
    if( ( ret = ctx->md_info->update_func( ctx->md_ctx, tmp,
                                           ctx->md_info->size ) ) != 0 )
        return( ret );
    return( ctx->md_info->finish_func( ctx->md_ctx, output ) );
}

int mbedtls_md_hmac_reset( mbedtls_md_context_t *ctx )
{
    int ret;
    unsigned char *ipad;

    if( ctx == NULL || ctx->md_info == NULL || ctx->hmac_ctx == NULL )
        return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );

    ipad = (unsigned char *) ctx->hmac_ctx;

    if( ( ret = ctx->md_info->starts_func( ctx->md_ctx ) ) != 0 )
        return( ret );
    return( ctx->md_info->update_func( ctx->md_ctx, ipad,
                                       ctx->md_info->block_size ) );
}

int mbedtls_md_hmac( const mbedtls_md_info_t *md_info,
                     const unsigned char *key, size_t keylen,
                     const unsigned char *input, size_t ilen,
                     unsigned char *output )
{
    mbedtls_md_context_t ctx;
    int ret;

    if( md_info == NULL )
        return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );

    mbedtls_md_init( &ctx );

    if( ( ret = mbedtls_md_setup( &ctx, md_info, 1 ) ) != 0 )
        goto cleanup;

    if( ( ret = mbedtls_md_hmac_starts( &ctx, key, keylen ) ) != 0 )
        goto cleanup;
    if( ( ret = mbedtls_md_hmac_update( &ctx, input, ilen ) ) != 0 )
        goto cleanup;
    if( ( ret = mbedtls_md_hmac_finish( &ctx, output ) ) != 0 )
        goto cleanup;

cleanup:
    mbedtls_md_free( &ctx );

    return( ret );
}

int mbedtls_md_process( mbedtls_md_context_t *ctx, const unsigned char *data )
{
    if( ctx == NULL || ctx->md_info == NULL )
        return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );

    return( ctx->md_info->process_func( ctx->md_ctx, data ) );
}

unsigned char mbedtls_md_get_size( const mbedtls_md_info_t *md_info )
{
    if( md_info == NULL )
        return( 0 );

    return md_info->size;
}

mbedtls_md_type_t mbedtls_md_get_type( const mbedtls_md_info_t *md_info )
{
    if( md_info == NULL )
        return( MBEDTLS_MD_NONE );

    return md_info->type;
}