/*

 * Copyright (C) 2008-2012 Free Software Foundation, Inc.

 *

 * Author: Nikos Mavrogiannopoulos

 *

 * This file is part of GNUTLS.

 *

 * The GNUTLS library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public License

 * as published by the Free Software Foundation; either version 2.1 of

 * the License, or (at your option) any later version.

 *

 * This library 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

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public License

 * along with this program.  If not, see <https://www.gnu.org/licenses/>

 *

 */

/* This file provides the backend hash/mac API for nettle.

 */

#include "gnutls_int.h"

#include "hash_int.h"

#include "errors.h"

#include <nettle/md5.h>

#include <nettle/md2.h>

#include <nettle/sha.h>

#include <nettle/sha3.h>

#include <nettle/hmac.h>

#include <nettle/umac.h>

#include <nettle/hkdf.h>

#include <nettle/pbkdf2.h>

#include <nettle/cmac.h>

#if ENABLE_GOST

#include "gost/hmac-gost.h"

#ifndef HAVE_NETTLE_GOST28147_SET_KEY

#include "gost/gost28147.h"

#endif

#include "gost/cmac.h"

#endif

#include <nettle/gcm.h>

typedef void (*update_func)(void *, size_t, const uint8_t *);

typedef void (*digest_func)(void *, size_t, uint8_t *);

typedef void (*set_key_func)(void *, size_t, const uint8_t *);

typedef void (*set_nonce_func)(void *, size_t, const uint8_t *);

static int wrap_nettle_hash_init(gnutls_digest_algorithm_t algo, void **_ctx);

struct md5_sha1_ctx {

  struct md5_ctx md5;

  struct sha1_ctx sha1;

};

struct gmac_ctx {

  unsigned int pos;

  uint8_t buffer[GCM_BLOCK_SIZE];

  struct gcm_key key;

  struct gcm_ctx ctx;

  nettle_cipher_func *encrypt;

  union {

    struct aes128_ctx aes128;

    struct aes192_ctx aes192;

    struct aes256_ctx aes256;

  } cipher;

};

struct nettle_hash_ctx {

  union {

    struct md5_ctx md5;

    struct sha224_ctx sha224;

    struct sha256_ctx sha256;

    struct sha384_ctx sha384;

    struct sha512_ctx sha512;

    struct sha3_224_ctx sha3_224;

    struct sha3_256_ctx sha3_256;

    struct sha3_384_ctx sha3_384;

    struct sha3_512_ctx sha3_512;

    struct sha1_ctx sha1;

    struct md2_ctx md2;

    struct md5_sha1_ctx md5_sha1;

#if ENABLE_GOST

    struct gosthash94cp_ctx gosthash94cp;

    struct streebog256_ctx streebog256;

    struct streebog512_ctx streebog512;

#endif

  } ctx;

  void *ctx_ptr;

  gnutls_digest_algorithm_t algo;

  size_t length;

  update_func update;

  digest_func digest;

};

struct nettle_mac_ctx {

  union {

    struct hmac_md5_ctx md5;

    struct hmac_sha224_ctx sha224;

    struct hmac_sha256_ctx sha256;

    struct hmac_sha384_ctx sha384;

    struct hmac_sha512_ctx sha512;

    struct hmac_sha1_ctx sha1;

#if ENABLE_GOST

    struct hmac_gosthash94cp_ctx gosthash94cp;

    struct hmac_streebog256_ctx streebog256;

    struct hmac_streebog512_ctx streebog512;

    struct gost28147_imit_ctx gost28147_imit;

    struct cmac_magma_ctx magma;

    struct cmac_kuznyechik_ctx kuznyechik;

#endif

    struct umac96_ctx umac96;

    struct umac128_ctx umac128;

    struct cmac_aes128_ctx cmac128;

    struct cmac_aes256_ctx cmac256;

    struct gmac_ctx gmac;

  } ctx;

  void *ctx_ptr;

  gnutls_mac_algorithm_t algo;

  size_t length;

  update_func update;

  digest_func digest;

  set_key_func set_key;

  set_nonce_func set_nonce;

};

#if ENABLE_GOST

static void _wrap_gost28147_imit_set_key_tc26z(void *ctx, size_t len,

                 const uint8_t *key)

{

  gost28147_imit_set_param(ctx, &gost28147_param_TC26_Z);

  gost28147_imit_set_key(ctx, len, key);

}

static void _wrap_cmac_magma_set_key(void *ctx, size_t len, const uint8_t *key)

{

  cmac_magma_set_key(ctx, key);

}

static void _wrap_cmac_kuznyechik_set_key(void *ctx, size_t len,

            const uint8_t *key)

{

  cmac_kuznyechik_set_key(ctx, key);

}

#endif

static void _wrap_umac96_set_key(void *ctx, size_t len, const uint8_t *key)

{

  if (unlikely(len != 16))

    abort();

  umac96_set_key(ctx, key);

}

static void _wrap_umac128_set_key(void *ctx, size_t len, const uint8_t *key)

{

  if (unlikely(len != 16))

    abort();

  umac128_set_key(ctx, key);

}

static void _wrap_cmac128_set_key(void *ctx, size_t len, const uint8_t *key)

{

  if (unlikely(len != 16))

    abort();

  cmac_aes128_set_key(ctx, key);

}

static void _wrap_cmac256_set_key(void *ctx, size_t len, const uint8_t *key)

{

  if (unlikely(len != 32))

    abort();

  cmac_aes256_set_key(ctx, key);

}

static void _wrap_gmac_aes128_set_key(void *_ctx, size_t len,

              const uint8_t *key)

{

  struct gmac_ctx *ctx = _ctx;

  if (unlikely(len != 16))

    abort();

  aes128_set_encrypt_key(&ctx->cipher.aes128, key);

  gcm_set_key(&ctx->key, &ctx->cipher, ctx->encrypt);

  ctx->pos = 0;

}

static void _wrap_gmac_aes192_set_key(void *_ctx, size_t len,

              const uint8_t *key)

{

  struct gmac_ctx *ctx = _ctx;

  if (unlikely(len != 24))

    abort();

  aes192_set_encrypt_key(&ctx->cipher.aes192, key);

  gcm_set_key(&ctx->key, &ctx->cipher, ctx->encrypt);

  ctx->pos = 0;

}

static void _wrap_gmac_aes256_set_key(void *_ctx, size_t len,

              const uint8_t *key)

{

  struct gmac_ctx *ctx = _ctx;

  if (unlikely(len != 32))

    abort();

  aes256_set_encrypt_key(&ctx->cipher.aes256, key);

  gcm_set_key(&ctx->key, &ctx->cipher, ctx->encrypt);

  ctx->pos = 0;

}

static void _wrap_gmac_set_nonce(void *_ctx, size_t nonce_length,

         const uint8_t *nonce)

{

  struct gmac_ctx *ctx = _ctx;

  gcm_set_iv(&ctx->ctx, &ctx->key, nonce_length, nonce);

}

static void _wrap_gmac_update(void *_ctx, size_t length, const uint8_t *data)

{

  struct gmac_ctx *ctx = _ctx;

  if (ctx->pos + length < GCM_BLOCK_SIZE) {

    memcpy(&ctx->buffer[ctx->pos], data, length);

    ctx->pos += length;

    return;

  }

  if (ctx->pos) {

    memcpy(&ctx->buffer[ctx->pos], data, GCM_BLOCK_SIZE - ctx->pos);

    gcm_update(&ctx->ctx, &ctx->key, GCM_BLOCK_SIZE, ctx->buffer);

    data += GCM_BLOCK_SIZE - ctx->pos;

    length -= GCM_BLOCK_SIZE - ctx->pos;

  }

  if (length >= GCM_BLOCK_SIZE) {

    gcm_update(&ctx->ctx, &ctx->key,

         length / GCM_BLOCK_SIZE * GCM_BLOCK_SIZE, data);

    data += length / GCM_BLOCK_SIZE * GCM_BLOCK_SIZE;

    length %= GCM_BLOCK_SIZE;

  }

  memcpy(ctx->buffer, data, length);

  ctx->pos = length;

}

static void _wrap_gmac_digest(void *_ctx, size_t length, uint8_t *digest)

{

  struct gmac_ctx *ctx = _ctx;

  if (ctx->pos)

    gcm_update(&ctx->ctx, &ctx->key, ctx->pos, ctx->buffer);

  gcm_digest(&ctx->ctx, &ctx->key, &ctx->cipher, ctx->encrypt, length,

       digest);

  ctx->pos = 0;

}

static int _mac_ctx_init(gnutls_mac_algorithm_t algo,

       struct nettle_mac_ctx *ctx)

{

  /* Any FIPS140-2 related enforcement is performed on

   * gnutls_hash_init() and gnutls_hmac_init() */

  ctx->set_nonce = NULL;

  switch (algo) {

  case GNUTLS_MAC_MD5:

    ctx->update = (update_func)hmac_md5_update;

    ctx->digest = (digest_func)hmac_md5_digest;

    ctx->set_key = (set_key_func)hmac_md5_set_key;

    ctx->ctx_ptr = &ctx->ctx.md5;

    ctx->length = MD5_DIGEST_SIZE;

    break;

  case GNUTLS_MAC_SHA1:

    ctx->update = (update_func)hmac_sha1_update;

    ctx->digest = (digest_func)hmac_sha1_digest;

    ctx->set_key = (set_key_func)hmac_sha1_set_key;

    ctx->ctx_ptr = &ctx->ctx.sha1;

    ctx->length = SHA1_DIGEST_SIZE;

    break;

  case GNUTLS_MAC_SHA224:

    ctx->update = (update_func)hmac_sha224_update;

    ctx->digest = (digest_func)hmac_sha224_digest;

    ctx->set_key = (set_key_func)hmac_sha224_set_key;

    ctx->ctx_ptr = &ctx->ctx.sha224;

    ctx->length = SHA224_DIGEST_SIZE;

    break;

  case GNUTLS_MAC_SHA256:

    ctx->update = (update_func)hmac_sha256_update;

    ctx->digest = (digest_func)hmac_sha256_digest;

    ctx->set_key = (set_key_func)hmac_sha256_set_key;

    ctx->ctx_ptr = &ctx->ctx.sha256;

    ctx->length = SHA256_DIGEST_SIZE;

    break;

  case GNUTLS_MAC_SHA384:

    ctx->update = (update_func)hmac_sha384_update;

    ctx->digest = (digest_func)hmac_sha384_digest;

    ctx->set_key = (set_key_func)hmac_sha384_set_key;

    ctx->ctx_ptr = &ctx->ctx.sha384;

    ctx->length = SHA384_DIGEST_SIZE;

    break;

  case GNUTLS_MAC_SHA512:

    ctx->update = (update_func)hmac_sha512_update;

    ctx->digest = (digest_func)hmac_sha512_digest;

    ctx->set_key = (set_key_func)hmac_sha512_set_key;

    ctx->ctx_ptr = &ctx->ctx.sha512;

    ctx->length = SHA512_DIGEST_SIZE;

    break;

#if ENABLE_GOST

  case GNUTLS_MAC_GOSTR_94:

    ctx->update = (update_func)hmac_gosthash94cp_update;

    ctx->digest = (digest_func)hmac_gosthash94cp_digest;

    ctx->set_key = (set_key_func)hmac_gosthash94cp_set_key;

    ctx->ctx_ptr = &ctx->ctx.gosthash94cp;

    ctx->length = GOSTHASH94CP_DIGEST_SIZE;

    break;

  case GNUTLS_MAC_STREEBOG_256:

    ctx->update = (update_func)hmac_streebog256_update;

    ctx->digest = (digest_func)hmac_streebog256_digest;

    ctx->set_key = (set_key_func)hmac_streebog256_set_key;

    ctx->ctx_ptr = &ctx->ctx.streebog256;

    ctx->length = STREEBOG256_DIGEST_SIZE;

    break;

  case GNUTLS_MAC_STREEBOG_512:

    ctx->update = (update_func)hmac_streebog512_update;

    ctx->digest = (digest_func)hmac_streebog512_digest;

    ctx->set_key = (set_key_func)hmac_streebog512_set_key;

    ctx->ctx_ptr = &ctx->ctx.streebog512;

    ctx->length = STREEBOG512_DIGEST_SIZE;

    break;

  case GNUTLS_MAC_GOST28147_TC26Z_IMIT:

    ctx->update = (update_func)gost28147_imit_update;

    ctx->digest = (digest_func)gost28147_imit_digest;

    ctx->set_key = _wrap_gost28147_imit_set_key_tc26z;

    ctx->ctx_ptr = &ctx->ctx.gost28147_imit;

    ctx->length = GOST28147_IMIT_DIGEST_SIZE;

    break;

  case GNUTLS_MAC_MAGMA_OMAC:

    ctx->update = (update_func)cmac_magma_update;

    ctx->digest = (digest_func)cmac_magma_digest;

    ctx->set_key = _wrap_cmac_magma_set_key;

    ctx->ctx_ptr = &ctx->ctx.magma;

    ctx->length = CMAC64_DIGEST_SIZE;

    break;

  case GNUTLS_MAC_KUZNYECHIK_OMAC:

    ctx->update = (update_func)cmac_kuznyechik_update;

    ctx->digest = (digest_func)cmac_kuznyechik_digest;

    ctx->set_key = _wrap_cmac_kuznyechik_set_key;

    ctx->ctx_ptr = &ctx->ctx.kuznyechik;

    ctx->length = CMAC128_DIGEST_SIZE;

    break;

#endif

  case GNUTLS_MAC_UMAC_96:

    ctx->update = (update_func)umac96_update;

    ctx->digest = (digest_func)umac96_digest;

    ctx->set_key = _wrap_umac96_set_key;

    ctx->set_nonce = (set_nonce_func)umac96_set_nonce;

    ctx->ctx_ptr = &ctx->ctx.umac96;

    ctx->length = 12;

    break;

  case GNUTLS_MAC_UMAC_128:

    ctx->update = (update_func)umac128_update;

    ctx->digest = (digest_func)umac128_digest;

    ctx->set_key = _wrap_umac128_set_key;

    ctx->set_nonce = (set_nonce_func)umac128_set_nonce;

    ctx->ctx_ptr = &ctx->ctx.umac128;

    ctx->length = 16;

    break;

  case GNUTLS_MAC_AES_CMAC_128:

    ctx->update = (update_func)cmac_aes128_update;

    ctx->digest = (digest_func)cmac_aes128_digest;

    ctx->set_key = _wrap_cmac128_set_key;

    ctx->ctx_ptr = &ctx->ctx.cmac128;

    ctx->length = CMAC128_DIGEST_SIZE;

    break;

  case GNUTLS_MAC_AES_CMAC_256:

    ctx->update = (update_func)cmac_aes256_update;

    ctx->digest = (digest_func)cmac_aes256_digest;

    ctx->set_key = _wrap_cmac256_set_key;

    ctx->ctx_ptr = &ctx->ctx.cmac256;

    ctx->length = CMAC128_DIGEST_SIZE;

    break;

  case GNUTLS_MAC_AES_GMAC_128:

    ctx->set_key = _wrap_gmac_aes128_set_key;

    ctx->set_nonce = _wrap_gmac_set_nonce;

    ctx->update = _wrap_gmac_update;

    ctx->digest = _wrap_gmac_digest;

    ctx->ctx_ptr = &ctx->ctx.gmac;

    ctx->length = GCM_DIGEST_SIZE;

    ctx->ctx.gmac.encrypt = (nettle_cipher_func *)aes128_encrypt;

    break;

  case GNUTLS_MAC_AES_GMAC_192:

    ctx->set_key = _wrap_gmac_aes192_set_key;

    ctx->set_nonce = _wrap_gmac_set_nonce;

    ctx->update = _wrap_gmac_update;

    ctx->digest = _wrap_gmac_digest;

    ctx->ctx_ptr = &ctx->ctx.gmac;

    ctx->length = GCM_DIGEST_SIZE;

    ctx->ctx.gmac.encrypt = (nettle_cipher_func *)aes192_encrypt;

    break;

  case GNUTLS_MAC_AES_GMAC_256:

    ctx->set_key = _wrap_gmac_aes256_set_key;

    ctx->set_nonce = _wrap_gmac_set_nonce;

    ctx->update = _wrap_gmac_update;

    ctx->digest = _wrap_gmac_digest;

    ctx->ctx_ptr = &ctx->ctx.gmac;

    ctx->length = GCM_DIGEST_SIZE;

    ctx->ctx.gmac.encrypt = (nettle_cipher_func *)aes256_encrypt;

    break;

  default:

    gnutls_assert();

    return GNUTLS_E_INVALID_REQUEST;

  }

  return 0;

}

static int wrap_nettle_mac_fast(gnutls_mac_algorithm_t algo, const void *nonce,

        size_t nonce_size, const void *key,

        size_t key_size, const void *text,

        size_t text_size, void *digest)

{

  struct nettle_mac_ctx ctx;

  int ret;

  ret = _mac_ctx_init(algo, &ctx);

  if (ret < 0)

    return gnutls_assert_val(ret);

  ctx.set_key(&ctx, key_size, key);

  if (ctx.set_nonce) {

    if (nonce == NULL || nonce_size == 0)

      return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

    ctx.set_nonce(&ctx, nonce_size, nonce);

  }

  ctx.update(&ctx, text_size, text);

  ctx.digest(&ctx, ctx.length, digest);

  zeroize_temp_key(&ctx, sizeof(ctx));

  return 0;

}

static int wrap_nettle_mac_exists(gnutls_mac_algorithm_t algo)

{

  switch (algo) {

  case GNUTLS_MAC_MD5:

  case GNUTLS_MAC_SHA1:

  case GNUTLS_MAC_SHA224:

  case GNUTLS_MAC_SHA256:

  case GNUTLS_MAC_SHA384:

  case GNUTLS_MAC_SHA512:

  case GNUTLS_MAC_UMAC_96:

  case GNUTLS_MAC_UMAC_128:

  case GNUTLS_MAC_AES_CMAC_128:

  case GNUTLS_MAC_AES_CMAC_256:

  case GNUTLS_MAC_AES_GMAC_128:

  case GNUTLS_MAC_AES_GMAC_192:

  case GNUTLS_MAC_AES_GMAC_256:

#if ENABLE_GOST

  case GNUTLS_MAC_GOSTR_94:

  case GNUTLS_MAC_STREEBOG_256:

  case GNUTLS_MAC_STREEBOG_512:

  case GNUTLS_MAC_GOST28147_TC26Z_IMIT:

  case GNUTLS_MAC_MAGMA_OMAC:

  case GNUTLS_MAC_KUZNYECHIK_OMAC:

#endif

    return 1;

  default:

    return 0;

  }

}

static int wrap_nettle_mac_init(gnutls_mac_algorithm_t algo, void **_ctx)

{

  struct nettle_mac_ctx *ctx;

  int ret;

  ctx = gnutls_calloc(1, sizeof(struct nettle_mac_ctx));

  if (ctx == NULL) {

    gnutls_assert();

    return GNUTLS_E_MEMORY_ERROR;

  }

  ctx->algo = algo;

  ret = _mac_ctx_init(algo, ctx);

  if (ret < 0) {

    gnutls_free(ctx);

    return gnutls_assert_val(ret);

  }

  *_ctx = ctx;

  return 0;

}

static void *wrap_nettle_mac_copy(const void *_ctx)

{

  const struct nettle_mac_ctx *ctx = _ctx;

  struct nettle_mac_ctx *new_ctx;

  ptrdiff_t off = (uint8_t *)ctx->ctx_ptr - (uint8_t *)(&ctx->ctx);

  new_ctx = gnutls_calloc(1, sizeof(struct nettle_mac_ctx));

  if (new_ctx == NULL)

    return NULL;

  memcpy(new_ctx, ctx, sizeof(*ctx));

  new_ctx->ctx_ptr = (uint8_t *)&new_ctx->ctx + off;

  return new_ctx;

}

static int wrap_nettle_mac_set_key(void *_ctx, const void *key, size_t keylen)

{

  struct nettle_mac_ctx *ctx = _ctx;

  ctx->set_key(ctx->ctx_ptr, keylen, key);

  return 0;

}

static int wrap_nettle_mac_set_nonce(void *_ctx, const void *nonce,

             size_t noncelen)

{

  struct nettle_mac_ctx *ctx = _ctx;

  if (ctx->set_nonce == NULL)

    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

  if (nonce == NULL || noncelen == 0)

    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

  ctx->set_nonce(ctx->ctx_ptr, noncelen, nonce);

  return GNUTLS_E_SUCCESS;

}

static int wrap_nettle_mac_update(void *_ctx, const void *text, size_t textsize)

{

  struct nettle_mac_ctx *ctx = _ctx;

  ctx->update(ctx->ctx_ptr, textsize, text);

  return GNUTLS_E_SUCCESS;

}

static int wrap_nettle_mac_output(void *src_ctx, void *digest,

          size_t digestsize)

{

  struct nettle_mac_ctx *ctx;

  ctx = src_ctx;

  if (digestsize < ctx->length) {

    gnutls_assert();

    return GNUTLS_E_SHORT_MEMORY_BUFFER;

  }

  ctx->digest(ctx->ctx_ptr, digestsize, digest);

  return 0;

}

static void wrap_nettle_mac_deinit(void *hd)

{

  struct nettle_mac_ctx *ctx = hd;

  zeroize_temp_key(ctx, sizeof(*ctx));

  gnutls_free(ctx);

}

/* Hash functions 

 */

static int wrap_nettle_hash_update(void *_ctx, const void *text,

           size_t textsize)

{

  struct nettle_hash_ctx *ctx = _ctx;

  ctx->update(ctx->ctx_ptr, textsize, text);

  return GNUTLS_E_SUCCESS;

}

static void wrap_nettle_hash_deinit(void *hd)

{

  gnutls_free(hd);

}

static int wrap_nettle_hash_exists(gnutls_digest_algorithm_t algo)

{

  switch (algo) {

  case GNUTLS_DIG_MD5:

  case GNUTLS_DIG_SHA1:

  case GNUTLS_DIG_MD5_SHA1:

  case GNUTLS_DIG_SHA224:

  case GNUTLS_DIG_SHA256:

  case GNUTLS_DIG_SHA384:

  case GNUTLS_DIG_SHA512:

#ifdef NETTLE_SHA3_FIPS202

  case GNUTLS_DIG_SHA3_224:

  case GNUTLS_DIG_SHA3_256:

  case GNUTLS_DIG_SHA3_384:

  case GNUTLS_DIG_SHA3_512:

#endif

  case GNUTLS_DIG_SHAKE_128:

  case GNUTLS_DIG_SHAKE_256:

  case GNUTLS_DIG_MD2:

  case GNUTLS_DIG_RMD160:

#if ENABLE_GOST

  case GNUTLS_DIG_GOSTR_94:

  case GNUTLS_DIG_STREEBOG_256:

  case GNUTLS_DIG_STREEBOG_512:

#endif

    return 1;

  default:

    return 0;

  }

}

static void _md5_sha1_update(void *_ctx, size_t len, const uint8_t *data)

{

  struct md5_sha1_ctx *ctx = _ctx;

  md5_update(&ctx->md5, len, data);

  sha1_update(&ctx->sha1, len, data);

}

static void _md5_sha1_digest(void *_ctx, size_t len, uint8_t *digest)

{

  struct md5_sha1_ctx *ctx = _ctx;

  md5_digest(&ctx->md5, len <= MD5_DIGEST_SIZE ? len : MD5_DIGEST_SIZE,

       digest);

  if (len > MD5_DIGEST_SIZE)

    sha1_digest(&ctx->sha1, len - MD5_DIGEST_SIZE,

          digest + MD5_DIGEST_SIZE);

}

static int _ctx_init(gnutls_digest_algorithm_t algo,

         struct nettle_hash_ctx *ctx)

{

  /* Any FIPS140-2 related enforcement is performed on

   * gnutls_hash_init() and gnutls_hmac_init() */

  switch (algo) {

  case GNUTLS_DIG_MD5:

    md5_init(&ctx->ctx.md5);

    ctx->update = (update_func)md5_update;

    ctx->digest = (digest_func)md5_digest;

    ctx->ctx_ptr = &ctx->ctx.md5;

    ctx->length = MD5_DIGEST_SIZE;

    break;

  case GNUTLS_DIG_SHA1:

    sha1_init(&ctx->ctx.sha1);

    ctx->update = (update_func)sha1_update;

    ctx->digest = (digest_func)sha1_digest;

    ctx->ctx_ptr = &ctx->ctx.sha1;

    ctx->length = SHA1_DIGEST_SIZE;

    break;

  case GNUTLS_DIG_MD5_SHA1:

    md5_init(&ctx->ctx.md5_sha1.md5);

    sha1_init(&ctx->ctx.md5_sha1.sha1);

    ctx->update = (update_func)_md5_sha1_update;

    ctx->digest = (digest_func)_md5_sha1_digest;

    ctx->ctx_ptr = &ctx->ctx.md5_sha1;

    ctx->length = MD5_DIGEST_SIZE + SHA1_DIGEST_SIZE;

    break;

  case GNUTLS_DIG_SHA224:

    sha224_init(&ctx->ctx.sha224);

    ctx->update = (update_func)sha224_update;

    ctx->digest = (digest_func)sha224_digest;

    ctx->ctx_ptr = &ctx->ctx.sha224;

    ctx->length = SHA224_DIGEST_SIZE;

    break;

  case GNUTLS_DIG_SHA256:

    sha256_init(&ctx->ctx.sha256);

    ctx->update = (update_func)sha256_update;

    ctx->digest = (digest_func)sha256_digest;

    ctx->ctx_ptr = &ctx->ctx.sha256;

    ctx->length = SHA256_DIGEST_SIZE;

    break;

  case GNUTLS_DIG_SHA384:

    sha384_init(&ctx->ctx.sha384);

    ctx->update = (update_func)sha384_update;

    ctx->digest = (digest_func)sha384_digest;

    ctx->ctx_ptr = &ctx->ctx.sha384;

    ctx->length = SHA384_DIGEST_SIZE;

    break;

  case GNUTLS_DIG_SHA512:

    sha512_init(&ctx->ctx.sha512);

    ctx->update = (update_func)sha512_update;

    ctx->digest = (digest_func)sha512_digest;

    ctx->ctx_ptr = &ctx->ctx.sha512;

    ctx->length = SHA512_DIGEST_SIZE;

    break;

#ifdef NETTLE_SHA3_FIPS202

  case GNUTLS_DIG_SHA3_224:

    sha3_224_init(&ctx->ctx.sha3_224);

    ctx->update = (update_func)sha3_224_update;

    ctx->digest = (digest_func)sha3_224_digest;

    ctx->ctx_ptr = &ctx->ctx.sha3_224;

    ctx->length = SHA3_224_DIGEST_SIZE;

    break;

  case GNUTLS_DIG_SHA3_256:

    sha3_256_init(&ctx->ctx.sha3_256);

    ctx->update = (update_func)sha3_256_update;

    ctx->digest = (digest_func)sha3_256_digest;

    ctx->ctx_ptr = &ctx->ctx.sha3_256;

    ctx->length = SHA3_256_DIGEST_SIZE;

    break;

  case GNUTLS_DIG_SHA3_384:

    sha3_384_init(&ctx->ctx.sha3_384);

    ctx->update = (update_func)sha3_384_update;

    ctx->digest = (digest_func)sha3_384_digest;

    ctx->ctx_ptr = &ctx->ctx.sha3_384;

    ctx->length = SHA3_384_DIGEST_SIZE;

    break;

  case GNUTLS_DIG_SHA3_512:

    sha3_512_init(&ctx->ctx.sha3_512);

    ctx->update = (update_func)sha3_512_update;

    ctx->digest = (digest_func)sha3_512_digest;

    ctx->ctx_ptr = &ctx->ctx.sha3_512;

    ctx->length = SHA3_512_DIGEST_SIZE;

    break;

#endif

  case GNUTLS_DIG_MD2:

    md2_init(&ctx->ctx.md2);

    ctx->update = (update_func)md2_update;

    ctx->digest = (digest_func)md2_digest;

    ctx->ctx_ptr = &ctx->ctx.md2;

    ctx->length = MD2_DIGEST_SIZE;

    break;

#if ENABLE_GOST

  case GNUTLS_DIG_GOSTR_94:

    gosthash94cp_init(&ctx->ctx.gosthash94cp);

    ctx->update = (update_func)gosthash94cp_update;

    ctx->digest = (digest_func)gosthash94cp_digest;

    ctx->ctx_ptr = &ctx->ctx.gosthash94cp;

    ctx->length = GOSTHASH94_DIGEST_SIZE;

    break;

  case GNUTLS_DIG_STREEBOG_256:

    streebog256_init(&ctx->ctx.streebog256);

    ctx->update = (update_func)streebog256_update;

    ctx->digest = (digest_func)streebog256_digest;

    ctx->ctx_ptr = &ctx->ctx.streebog256;

    ctx->length = STREEBOG256_DIGEST_SIZE;

    break;

  case GNUTLS_DIG_STREEBOG_512:

    streebog512_init(&ctx->ctx.streebog512);

    ctx->update = (update_func)streebog512_update;

    ctx->digest = (digest_func)streebog512_digest;

    ctx->ctx_ptr = &ctx->ctx.streebog512;

    ctx->length = STREEBOG512_DIGEST_SIZE;

    break;

#endif

  default:

    gnutls_assert();

    return GNUTLS_E_INVALID_REQUEST;

  }

  return 0;

}

static int wrap_nettle_hash_fast(gnutls_digest_algorithm_t algo,

         const void *text, size_t text_size,

         void *digest)

{

  struct nettle_hash_ctx ctx;

  int ret;

  ret = _ctx_init(algo, &ctx);

  if (ret < 0)

    return gnutls_assert_val(ret);

  if (text_size > 0) {

    ctx.update(&ctx, text_size, text);

  }

  ctx.digest(&ctx, ctx.length, digest);

  zeroize_temp_key(&ctx, sizeof(ctx));

  return 0;

}

static int wrap_nettle_hash_init(gnutls_digest_algorithm_t algo, void **_ctx)

{

  struct nettle_hash_ctx *ctx;

  int ret;

  ctx = gnutls_malloc(sizeof(struct nettle_hash_ctx));

  if (ctx == NULL) {

    gnutls_assert();

    return GNUTLS_E_MEMORY_ERROR;

  }

  ctx->algo = algo;

  if ((ret = _ctx_init(algo, ctx)) < 0) {

    gnutls_assert();

    gnutls_free(ctx);

    return ret;

  }

  *_ctx = ctx;

  return 0;

}

static void *wrap_nettle_hash_copy(const void *_ctx)

{

  const struct nettle_hash_ctx *ctx = _ctx;

  struct nettle_hash_ctx *new_ctx;

  ptrdiff_t off = (uint8_t *)ctx->ctx_ptr - (uint8_t *)(&ctx->ctx);

  new_ctx = gnutls_calloc(1, sizeof(struct nettle_hash_ctx));

  if (new_ctx == NULL)

    return NULL;

  memcpy(new_ctx, ctx, sizeof(*ctx));

  new_ctx->ctx_ptr = (uint8_t *)&new_ctx->ctx + off;

  return new_ctx;

}

static int wrap_nettle_hash_output(void *src_ctx, void *digest,

           size_t digestsize)

{

  struct nettle_hash_ctx *ctx;

  ctx = src_ctx;

  if (digestsize < ctx->length) {

    gnutls_assert();

    return GNUTLS_E_SHORT_MEMORY_BUFFER;

  }

  ctx->digest(ctx->ctx_ptr, digestsize, digest);

  return 0;

}

/* KDF functions based on MAC

 */

static int wrap_nettle_hkdf_extract(gnutls_mac_algorithm_t mac, const void *key,

            size_t keysize, const void *salt,

            size_t saltsize, void *output)

{

  struct nettle_mac_ctx ctx;

  int ret;

  ret = _mac_ctx_init(mac, &ctx);

  if (ret < 0)

    return gnutls_assert_val(ret);

  ctx.set_key(&ctx, saltsize, salt);

  hkdf_extract(&ctx.ctx, ctx.update, ctx.digest, ctx.length, keysize, key,

         output);

  zeroize_temp_key(&ctx, sizeof(ctx));

  return 0;

}

static int wrap_nettle_hkdf_expand(gnutls_mac_algorithm_t mac, const void *key,

           size_t keysize, const void *info,

           size_t infosize, void *output, size_t length)

{

  struct nettle_mac_ctx ctx;

  int ret;

  ret = _mac_ctx_init(mac, &ctx);

  if (ret < 0)

    return gnutls_assert_val(ret);

  /* RFC 5869 2.3: L must be <= 255 * HashLen */

  if (length > ctx.length * 255) {

    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

  }