/*

 * Copyright (c) 2006 - 2007 Kungliga Tekniska Högskolan

 * (Royal Institute of Technology, Stockholm, Sweden).

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 *

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * 3. Neither the name of the Institute nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 */

#include <config.h>

#include <roken.h>

#include <hmac.h>

void

HMAC_CTX_init(HMAC_CTX *ctx)

{

    memset(ctx, 0, sizeof(*ctx));

}

void

HMAC_CTX_cleanup(HMAC_CTX *ctx)

{

    if (ctx->buf) {

  memset_s(ctx->buf, ctx->key_length, 0, ctx->key_length);

  free(ctx->buf);

  ctx->buf = NULL;

    }

    if (ctx->opad) {

  memset_s(ctx->opad, EVP_MD_block_size(ctx->md), 0, EVP_MD_block_size(ctx->md));

  free(ctx->opad);

  ctx->opad = NULL;

    }

    if (ctx->ipad) {

  memset_s(ctx->ipad, EVP_MD_block_size(ctx->md), 0, EVP_MD_block_size(ctx->md));

  free(ctx->ipad);

  ctx->ipad = NULL;

    }

    if (ctx->ctx) {

  EVP_MD_CTX_destroy(ctx->ctx);

  ctx->ctx = NULL;

    }

}

HMAC_CTX *

HMAC_CTX_new(void)

{

    return calloc(1, sizeof(HMAC_CTX));

}

void

HMAC_CTX_free(HMAC_CTX *ctx)

{

    HMAC_CTX_cleanup(ctx);

    free(ctx);

}

size_t

HMAC_size(const HMAC_CTX *ctx)

{

    return EVP_MD_size(ctx->md);

}

int

HMAC_Init_ex(HMAC_CTX *ctx,

       const void *key,

       size_t keylen,

       const EVP_MD *md,

       ENGINE *engine)

{

    unsigned char *p;

    size_t i, blockSize;

    blockSize = EVP_MD_block_size(md);

    if (ctx->md != md) {

        if (ctx->md != NULL)

            HMAC_CTX_cleanup(ctx);

  ctx->md = md;

  ctx->key_length = EVP_MD_size(ctx->md);

        ctx->opad = NULL;

        ctx->ipad = NULL;

        ctx->ctx = NULL;

  ctx->buf = malloc(ctx->key_length);

        if (ctx->buf)

            ctx->opad = malloc(blockSize);

        if (ctx->opad)

            ctx->ipad = malloc(blockSize);

        if (ctx->ipad)

            ctx->ctx = EVP_MD_CTX_create();

    }

    /* We do this check here to quiet scan-build */

    if (!ctx->buf || !ctx->opad || !ctx->ipad || !ctx->ctx)

  return 0;

#if 0

    ctx->engine = engine;

#endif

    if (keylen > blockSize) {

  if (EVP_Digest(key, keylen, ctx->buf, NULL, ctx->md, engine) == 0)

            return 0;

  key = ctx->buf;

  keylen = EVP_MD_size(ctx->md);

    }

    memset(ctx->ipad, 0x36, blockSize);

    memset(ctx->opad, 0x5c, blockSize);

    for (i = 0, p = ctx->ipad; i < keylen; i++)

  p[i] ^= ((const unsigned char *)key)[i];

    for (i = 0, p = ctx->opad; i < keylen; i++)

  p[i] ^= ((const unsigned char *)key)[i];

    if (EVP_DigestInit_ex(ctx->ctx, ctx->md, ctx->engine) == 0)

        return 0;

    EVP_DigestUpdate(ctx->ctx, ctx->ipad, EVP_MD_block_size(ctx->md));

    return 1;

}

void

HMAC_Update(HMAC_CTX *ctx, const void *data, size_t len)

{

    EVP_DigestUpdate(ctx->ctx, data, len);

}

void

HMAC_Final(HMAC_CTX *ctx, void *md, unsigned int *len)

{

    EVP_DigestFinal_ex(ctx->ctx, ctx->buf, NULL);

    EVP_DigestInit_ex(ctx->ctx, ctx->md, ctx->engine);

    EVP_DigestUpdate(ctx->ctx, ctx->opad, EVP_MD_block_size(ctx->md));

    EVP_DigestUpdate(ctx->ctx, ctx->buf, ctx->key_length);

    EVP_DigestFinal_ex(ctx->ctx, md, len);

}

void *

HMAC(const EVP_MD *md,

     const void *key, size_t key_size,

     const void *data, size_t data_size,

     void *hash, unsigned int *hash_len)

{

    HMAC_CTX ctx;

    HMAC_CTX_init(&ctx);

    if (HMAC_Init_ex(&ctx, key, key_size, md, NULL) == 0) {

        HMAC_CTX_cleanup(&ctx);

        return NULL;

    }

    HMAC_Update(&ctx, data, data_size);

    HMAC_Final(&ctx, hash, hash_len);

    HMAC_CTX_cleanup(&ctx);

    return hash;

}