library/md.c

/**
 * \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
 *  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)
 */

#if !defined(MBEDTLS_CONFIG_FILE)
#include "mbedtls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif

#if defined(MBEDTLS_MD_C)

#include "mbedtls/md.h"
#include "mbedtls/platform_util.h"

#if defined(MBEDTLS_PLATFORM_C)
#include "mbedtls/platform.h"
#else
#include <stdlib.h>
#define mbedtls_calloc    calloc
#define mbedtls_free       free
#endif

#include <string.h>

#if defined(MBEDTLS_FS_IO)
#include <stdio.h>
#endif

#if !defined(MBEDTLS_MD_SINGLE_HASH)
/*
 *
 * Definitions of MD information structures for various digests.
 *
 */

/*
 * MD-2
 */
#if defined(MBEDTLS_MD2_C)
const mbedtls_md_info_t mbedtls_md2_info = {
    MBEDTLS_MD_MD2,
    "MD2",
    16,
    16,
    mbedtls_md2_starts_wrap,
    mbedtls_md2_update_wrap,
    mbedtls_md2_finish_wrap,
    mbedtls_md2_ret,
    mbedtls_md2_ctx_alloc,
    mbedtls_md2_ctx_free,
    mbedtls_md2_clone_wrap,
    mbedtls_md2_process_wrap,
};
#endif /* MBEDTLS_MD2_C */

/*
 * MD-4
 */

#if defined(MBEDTLS_MD4_C)
const mbedtls_md_info_t mbedtls_md4_info = {
    MBEDTLS_MD_MD4,
    "MD4",
    16,
    64,
    mbedtls_md4_starts_wrap,
    mbedtls_md4_update_wrap,
    mbedtls_md4_finish_wrap,
    mbedtls_md4_ret,
    mbedtls_md4_ctx_alloc,
    mbedtls_md4_ctx_free,
    mbedtls_md4_clone_wrap,
    mbedtls_md4_process_wrap,
};
#endif /* MBEDTLS_MD4_C */

/*
 * MD-5
 */

#if defined(MBEDTLS_MD5_C)
const mbedtls_md_info_t mbedtls_md5_info = {
    MBEDTLS_MD_MD5,
    "MD5",
    16,
    64,
    mbedtls_md5_starts_wrap,
    mbedtls_md5_update_wrap,
    mbedtls_md5_finish_wrap,
    mbedtls_md5_ret,
    mbedtls_md5_ctx_alloc,
    mbedtls_md5_ctx_free,
    mbedtls_md5_clone_wrap,
    mbedtls_md5_process_wrap,
};
#endif /* MBEDTLS_MD5_C */

/*
 * RIPEMD-160
 */

#if defined(MBEDTLS_RIPEMD160_C)
const mbedtls_md_info_t mbedtls_ripemd160_info = {
    MBEDTLS_MD_RIPEMD160,
    "RIPEMD160",
    20,
    64,
    mbedtls_ripemd160_starts_wrap,
    mbedtls_ripemd160_update_wrap,
    mbedtls_ripemd160_finish_wrap,
    mbedtls_ripemd160_ret,
    mbedtls_ripemd160_ctx_alloc,
    mbedtls_ripemd160_ctx_free,
    mbedtls_ripemd160_clone_wrap,
    mbedtls_ripemd160_process_wrap,
};
#endif /* MBEDTLS_RIPEMD160_C */

/*
 * SHA-1
 */

#if defined(MBEDTLS_SHA1_C)
const mbedtls_md_info_t mbedtls_sha1_info = {
    MBEDTLS_MD_SHA1,
    "SHA1",
    20,
    64,
    mbedtls_sha1_starts_wrap,
    mbedtls_sha1_update_wrap,
    mbedtls_sha1_finish_wrap,
    mbedtls_sha1_ret,
    mbedtls_sha1_ctx_alloc,
    mbedtls_sha1_ctx_free,
    mbedtls_sha1_clone_wrap,
    mbedtls_sha1_process_wrap,
};
#endif /* MBEDTLS_SHA1_C */

/*
 * SHA-224 and SHA-256
 */

#if defined(MBEDTLS_SHA256_C)
#if !defined(MBEDTLS_SHA256_NO_SHA224)
const mbedtls_md_info_t mbedtls_sha224_info = {
    MBEDTLS_MD_SHA224,
    "SHA224",
    28,
    64,
    mbedtls_sha224_starts_wrap,
    mbedtls_sha224_update_wrap,
    mbedtls_sha224_finish_wrap,
    mbedtls_sha224_wrap,
    mbedtls_sha224_ctx_alloc,
    mbedtls_sha224_ctx_free,
    mbedtls_sha224_clone_wrap,
    mbedtls_sha224_process_wrap,
};
#endif /* !MBEDTLS_SHA256_NO_SHA224 */
const mbedtls_md_info_t mbedtls_sha256_info =
    MBEDTLS_MD_INFO( MBEDTLS_MD_INFO_SHA256 );
#endif /* MBEDTLS_SHA256_C */

/*
 * SHA-384 and SHA-512
 */

#if defined(MBEDTLS_SHA512_C)
const mbedtls_md_info_t mbedtls_sha384_info = {
    MBEDTLS_MD_SHA384,
    "SHA384",
    48,
    128,
    mbedtls_sha384_starts_wrap,
    mbedtls_sha384_update_wrap,
    mbedtls_sha384_finish_wrap,
    mbedtls_sha384_wrap,
    mbedtls_sha384_ctx_alloc,
    mbedtls_sha384_ctx_free,
    mbedtls_sha384_clone_wrap,
    mbedtls_sha384_process_wrap,
};
const mbedtls_md_info_t mbedtls_sha512_info = {
    MBEDTLS_MD_SHA512,
    "SHA512",
    64,
    128,
    mbedtls_sha512_starts_wrap,
    mbedtls_sha384_update_wrap,
    mbedtls_sha384_finish_wrap,
    mbedtls_sha512_wrap,
    mbedtls_sha384_ctx_alloc,
    mbedtls_sha384_ctx_free,
    mbedtls_sha384_clone_wrap,
    mbedtls_sha384_process_wrap,
};
#endif /* MBEDTLS_SHA512_C */

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

#if defined(MBEDTLS_SHA512_C)
        MBEDTLS_MD_SHA512,
        MBEDTLS_MD_SHA384,
#endif

#if defined(MBEDTLS_SHA256_C)
        MBEDTLS_MD_SHA256,
#if !defined(MBEDTLS_SHA256_NO_SHA224)
        MBEDTLS_MD_SHA224,
#endif
#endif /* MBEDTLS_SHA256_C */

#if defined(MBEDTLS_SHA1_C)
        MBEDTLS_MD_SHA1,
#endif

#if defined(MBEDTLS_RIPEMD160_C)
        MBEDTLS_MD_RIPEMD160,
#endif

#if defined(MBEDTLS_MD5_C)
        MBEDTLS_MD_MD5,
#endif

#if defined(MBEDTLS_MD4_C)
        MBEDTLS_MD_MD4,
#endif

#if defined(MBEDTLS_MD2_C)
        MBEDTLS_MD_MD2,
#endif

        MBEDTLS_MD_NONE
};

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

mbedtls_md_handle_t mbedtls_md_info_from_string( const char *md_name )
{
    if( NULL == md_name )
        return( NULL );

    /* Get the appropriate digest information */
#if defined(MBEDTLS_MD2_C)
    if( !strcmp( "MD2", md_name ) )
        return mbedtls_md_info_from_type( MBEDTLS_MD_MD2 );
#endif
#if defined(MBEDTLS_MD4_C)
    if( !strcmp( "MD4", md_name ) )
        return mbedtls_md_info_from_type( MBEDTLS_MD_MD4 );
#endif
#if defined(MBEDTLS_MD5_C)
    if( !strcmp( "MD5", md_name ) )
        return mbedtls_md_info_from_type( MBEDTLS_MD_MD5 );
#endif
#if defined(MBEDTLS_RIPEMD160_C)
    if( !strcmp( "RIPEMD160", md_name ) )
        return mbedtls_md_info_from_type( MBEDTLS_MD_RIPEMD160 );
#endif
#if defined(MBEDTLS_SHA1_C)
    if( !strcmp( "SHA1", md_name ) || !strcmp( "SHA", md_name ) )
        return mbedtls_md_info_from_type( MBEDTLS_MD_SHA1 );
#endif
#if defined(MBEDTLS_SHA256_C)
#if !defined(MBEDTLS_SHA256_NO_SHA224)
    if( !strcmp( "SHA224", md_name ) )
        return mbedtls_md_info_from_type( MBEDTLS_MD_SHA224 );
#endif
    if( !strcmp( "SHA256", md_name ) )
        return mbedtls_md_info_from_type( MBEDTLS_MD_SHA256 );
#endif /* MBEDTLS_SHA256_C */
#if defined(MBEDTLS_SHA512_C)
    if( !strcmp( "SHA384", md_name ) )
        return mbedtls_md_info_from_type( MBEDTLS_MD_SHA384 );
    if( !strcmp( "SHA512", md_name ) )
        return mbedtls_md_info_from_type( MBEDTLS_MD_SHA512 );
#endif
    return( NULL );
}

mbedtls_md_handle_t mbedtls_md_info_from_type( mbedtls_md_type_t md_type )
{
    switch( md_type )
    {
#if defined(MBEDTLS_MD2_C)
        case MBEDTLS_MD_MD2:
            return( &mbedtls_md2_info );
#endif
#if defined(MBEDTLS_MD4_C)
        case MBEDTLS_MD_MD4:
            return( &mbedtls_md4_info );
#endif
#if defined(MBEDTLS_MD5_C)
        case MBEDTLS_MD_MD5:
            return( &mbedtls_md5_info );
#endif
#if defined(MBEDTLS_RIPEMD160_C)
        case MBEDTLS_MD_RIPEMD160:
            return( &mbedtls_ripemd160_info );
#endif
#if defined(MBEDTLS_SHA1_C)
        case MBEDTLS_MD_SHA1:
            return( &mbedtls_sha1_info );
#endif
#if defined(MBEDTLS_SHA256_C)
#if !defined(MBEDTLS_SHA256_NO_SHA224)
        case MBEDTLS_MD_SHA224:
            return( &mbedtls_sha224_info );
#endif
        case MBEDTLS_MD_SHA256:
            return( &mbedtls_sha256_info );
#endif /* MBEDTLS_SHA256_C */
#if defined(MBEDTLS_SHA512_C)
        case MBEDTLS_MD_SHA384:
            return( &mbedtls_sha384_info );
        case MBEDTLS_MD_SHA512:
            return( &mbedtls_sha512_info );
#endif
        default:
            return( NULL );
    }
}

#else /* MBEDTLS_MD_SINGLE_HASH */

const int *mbedtls_md_list( void )
{
    static int single_hash[2] =
        { MBEDTLS_MD_INFO_TYPE( MBEDTLS_MD_SINGLE_HASH ),
          MBEDTLS_MD_INVALID_HANDLE };

    return( single_hash );
}

mbedtls_md_handle_t mbedtls_md_info_from_string( const char *md_name )
{
    static const char * const hash_name =
        MBEDTLS_MD_INFO_NAME( MBEDTLS_MD_SINGLE_HASH );

    if( md_name != NULL && strcmp( hash_name, md_name ) == 0 )
        return( MBEDTLS_MD_UNIQUE_VALID_HANDLE );

    return( MBEDTLS_MD_INVALID_HANDLE );
}

mbedtls_md_handle_t mbedtls_md_info_from_type( mbedtls_md_type_t md_type )
{
    static const mbedtls_md_type_t hash_type =
        MBEDTLS_MD_INFO_TYPE( MBEDTLS_MD_SINGLE_HASH );

    if( hash_type == md_type )
        return( MBEDTLS_MD_UNIQUE_VALID_HANDLE );

    return( MBEDTLS_MD_INVALID_HANDLE );
}

#endif /* MBEDTLS_MD_SINGLE_HASH */

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 || mbedtls_md_get_handle( ctx ) == MBEDTLS_MD_INVALID_HANDLE )
        return;

    if( ctx->md_ctx != NULL )
    {
        mbedtls_md_info_ctx_free( mbedtls_md_get_handle( ctx ), ctx->md_ctx );
    }

    if( ctx->hmac_ctx != NULL )
    {
        mbedtls_platform_zeroize( ctx->hmac_ctx,
            2 * mbedtls_md_info_block_size( mbedtls_md_get_handle( ctx ) ) );
        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 || mbedtls_md_get_handle( dst ) == MBEDTLS_MD_INVALID_HANDLE ||
        src == NULL || mbedtls_md_get_handle( src ) == MBEDTLS_MD_INVALID_HANDLE ||
        mbedtls_md_get_handle( dst ) != mbedtls_md_get_handle( src ) )
    {
        return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );
    }

    mbedtls_md_info_clone( mbedtls_md_get_handle( dst ),
                           dst->md_ctx, src->md_ctx );
    return( 0 );
}

#if ! defined(MBEDTLS_DEPRECATED_REMOVED)
int mbedtls_md_init_ctx( mbedtls_md_context_t *ctx, mbedtls_md_handle_t md_info )
{
    return mbedtls_md_setup( ctx, md_info, 1 );
}
#endif

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

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

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

#if !defined(MBEDTLS_MD_SINGLE_HASH)
    ctx->md_info = md_info;
#endif

    return( 0 );
}

#if !defined(MBEDTLS_MD_SINGLE_HASH)
int mbedtls_md_starts( mbedtls_md_context_t *ctx )
{
    return( mbedtls_md_starts_internal( ctx ) );
}

int mbedtls_md_update( mbedtls_md_context_t *ctx,
                       const unsigned char *input,
                       size_t ilen )
{
    return( mbedtls_md_update_internal( ctx, input, ilen ) );
}
#endif /* !MBEDTLS_MD_SINGLE_HASH */

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

    md_info = mbedtls_md_get_handle( ctx );
    if( md_info == MBEDTLS_MD_INVALID_HANDLE )
        return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );

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

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

    return( mbedtls_md_info_digest( md_info, input,
                                    ilen, output) );
}

#if defined(MBEDTLS_FS_IO)
int mbedtls_md_file( mbedtls_md_handle_t md_info, const char *path, unsigned char *output )
{
    int ret;
    FILE *f;
    size_t n;
    mbedtls_md_context_t ctx;
    unsigned char buf[1024];

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

    if( ( f = fopen( path, "rb" ) ) == NULL )
        return( MBEDTLS_ERR_MD_FILE_IO_ERROR );

    mbedtls_md_init( &ctx );

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

    ret = mbedtls_md_info_starts( md_info, ctx.md_ctx );
    if( ret != 0 )
        goto cleanup;

    while( ( n = fread( buf, 1, sizeof( buf ), f ) ) > 0 )
    {
        ret = mbedtls_md_info_update( md_info, ctx.md_ctx,
                                      buf, n );
        if( ret != 0 )
            goto cleanup;
    }

    if( ferror( f ) != 0 )
    {
        ret = MBEDTLS_ERR_MD_FILE_IO_ERROR;
    }
    else
    {
        ret = mbedtls_md_info_finish( md_info, ctx.md_ctx,
                                      output );
    }

cleanup:
    mbedtls_platform_zeroize( buf, sizeof( buf ) );
    fclose( f );
    mbedtls_md_free( &ctx );

    return( ret );
}
#endif /* MBEDTLS_FS_IO */

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;

    mbedtls_md_handle_t md_info;

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

    md_info = mbedtls_md_get_handle( ctx );
    if( md_info == MBEDTLS_MD_INVALID_HANDLE )
        return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );

    if( keylen > (size_t) mbedtls_md_info_block_size( md_info ) )
    {
        if( ( ret = mbedtls_md_info_starts( md_info, ctx->md_ctx ) ) != 0 )
            goto cleanup;

        if( ( ret = mbedtls_md_info_update( md_info, ctx->md_ctx,
                                            key, keylen ) ) != 0 )
        {
            goto cleanup;
        }

        if( ( ret = mbedtls_md_info_finish( md_info, ctx->md_ctx, sum ) ) != 0 )
            goto cleanup;

        keylen = mbedtls_md_info_size( md_info );
        key = sum;
    }

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

    memset( ipad, 0x36, mbedtls_md_info_block_size( md_info ) );
    memset( opad, 0x5C, mbedtls_md_info_block_size( md_info ) );

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

    if( ( ret = mbedtls_md_info_starts( md_info, ctx->md_ctx ) ) != 0 )
        goto cleanup;

    if( ( ret = mbedtls_md_info_update( md_info, ctx->md_ctx, ipad,
           mbedtls_md_info_block_size( md_info ) ) ) != 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 )
{
    mbedtls_md_handle_t md_info;

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

    md_info = mbedtls_md_get_handle( ctx );
    if( md_info == MBEDTLS_MD_INVALID_HANDLE )
        return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );

    return( mbedtls_md_info_update( md_info,
                                    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;

    mbedtls_md_handle_t md_info;

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

    md_info = mbedtls_md_get_handle( ctx );
    if( md_info == MBEDTLS_MD_INVALID_HANDLE )
        return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );

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

    if( ( ret = mbedtls_md_info_finish( md_info, ctx->md_ctx, tmp ) ) != 0 )
        return( ret );

    if( ( ret = mbedtls_md_info_starts( md_info, ctx->md_ctx ) ) != 0 )
        return( ret );

    if( ( ret = mbedtls_md_info_update( md_info, ctx->md_ctx, opad,
                       mbedtls_md_info_block_size( md_info ) ) ) != 0 )
    {
        return( ret );
    }

    if( ( ret = mbedtls_md_info_update( md_info, ctx->md_ctx, tmp,
                        mbedtls_md_info_size( md_info ) ) ) != 0 )
    {
        return( ret );
    }

    if( ( ret = mbedtls_md_info_finish( md_info, ctx->md_ctx, output ) ) != 0 )
        return( ret );

    return( 0 );
}

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

    mbedtls_md_handle_t md_info;

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

    md_info = mbedtls_md_get_handle( ctx );
    if( md_info == MBEDTLS_MD_INVALID_HANDLE )
        return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );

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

    ret = mbedtls_md_info_starts( md_info, ctx->md_ctx );
    if( ret != 0 )
        return( ret );

    ret = mbedtls_md_info_update( md_info,
                                  ctx->md_ctx, ipad,
                                  mbedtls_md_info_block_size( md_info ) );
    return( ret );
}

int mbedtls_md_hmac( mbedtls_md_handle_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 == MBEDTLS_MD_INVALID_HANDLE )
        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 )
{
    mbedtls_md_handle_t md_info;
    if( ctx == NULL )
        return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );

    md_info = mbedtls_md_get_handle( ctx );
    if( md_info == MBEDTLS_MD_INVALID_HANDLE )
        return( MBEDTLS_ERR_MD_BAD_INPUT_DATA );

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

unsigned char mbedtls_md_get_size( mbedtls_md_handle_t md_info )
{
    if( md_info == MBEDTLS_MD_INVALID_HANDLE )
        return( 0 );

    return mbedtls_md_info_size( md_info );
}

mbedtls_md_type_t mbedtls_md_get_type( mbedtls_md_handle_t md_info )
{
    if( md_info == MBEDTLS_MD_INVALID_HANDLE )
        return( MBEDTLS_MD_NONE );

    return mbedtls_md_info_type( md_info );
}

const char *mbedtls_md_get_name( mbedtls_md_handle_t md_info )
{
    if( md_info == MBEDTLS_MD_INVALID_HANDLE )
        return( NULL );

    return mbedtls_md_info_name( md_info );
}

#endif /* MBEDTLS_MD_C */