/src/gnutls/lib/nettle/cipher.c

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/*
 * Copyright (C) 2010-2012 Free Software Foundation, Inc.
 * Copyright (C) 2014 Red Hat, 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/>
 *
 */

/* Here lie nettle's wrappers for cipher support.
 */

#include "gnutls_int.h"
#include "errors.h"
#include "cipher_int.h"
#include <nettle/aes.h>
#include <nettle/camellia.h>
#include <nettle/arcfour.h>
#include <nettle/arctwo.h>
#include <nettle/salsa20.h>
#include <nettle/des.h>
#include <nettle/version.h>
#if ENABLE_GOST
#ifndef HAVE_NETTLE_GOST28147_SET_KEY
#include "gost/gost28147.h"
#else
#include <nettle/gost28147.h>
#endif
#ifndef HAVE_NETTLE_MAGMA_SET_KEY
#include "gost/magma.h"
#else
#include <nettle/magma.h>
#endif
#ifndef HAVE_NETTLE_KUZNYECHIK_SET_KEY
#include "gost/kuznyechik.h"
#else
#include <nettle/kuznyechik.h>
#endif
#include "gost/acpkm.h"
#include <nettle/ctr.h>
#endif
#include <nettle/nettle-meta.h>
#include <nettle/cbc.h>
#include <nettle/gcm.h>
#include <nettle/ccm.h>
#include <nettle/chacha.h>
#include <nettle/chacha-poly1305.h>
#include <nettle/cfb.h>
#include <nettle/xts.h>
#include <nettle/siv-cmac.h>
#ifdef HAVE_NETTLE_SIV_GCM_ENCRYPT_MESSAGE
#include <nettle/siv-gcm.h>
#else
#include "backport/siv-gcm.h"
#endif
#include "fips.h"
#include <intprops.h>

struct nettle_cipher_ctx;

/* Functions that refer to the nettle library.
 */
typedef void (*encrypt_func)(struct nettle_cipher_ctx *, size_t length,
           uint8_t *dst, const uint8_t *src);
typedef void (*decrypt_func)(struct nettle_cipher_ctx *, size_t length,
           uint8_t *dst, const uint8_t *src);

typedef void (*aead_encrypt_func)(struct nettle_cipher_ctx *, size_t nonce_size,
          const void *nonce, size_t auth_size,
          const void *auth, size_t tag_size,
          size_t length, uint8_t *dst,
          const uint8_t *src);
typedef int (*aead_decrypt_func)(struct nettle_cipher_ctx *, size_t nonce_size,
         const void *nonce, size_t auth_size,
         const void *auth, size_t tag_size,
         size_t length, uint8_t *dst,
         const uint8_t *src);

typedef void (*setiv_func)(void *ctx, size_t length, const uint8_t *);
typedef void (*gen_setkey_func)(void *ctx, size_t length, const uint8_t *);

struct nettle_cipher_st {
  gnutls_cipher_algorithm_t algo;
  unsigned ctx_size;
  nettle_cipher_func *encrypt_block;
  nettle_cipher_func *decrypt_block;
  unsigned block_size;
  unsigned key_size;
  unsigned max_iv_size;

  encrypt_func encrypt;
  decrypt_func decrypt;
  aead_encrypt_func aead_encrypt;
  aead_decrypt_func aead_decrypt;
  nettle_hash_update_func *auth;
  nettle_hash_digest_func *tag;
  nettle_set_key_func *set_encrypt_key;
  nettle_set_key_func *set_decrypt_key;
  gen_setkey_func gen_set_key; /* for arcfour which has variable key size */
  setiv_func set_iv;
};

struct nettle_cipher_ctx {
  const struct nettle_cipher_st *cipher;
  void *ctx_ptr; /* always 16-aligned */
  uint8_t iv[MAX_CIPHER_BLOCK_SIZE];
  unsigned iv_size;

  bool enc;
  size_t rekey_counter;
};

#define AES_GCM_ENCRYPT_MAX_BYTES ((1ULL << 36) - 32)
static inline int record_aes_gcm_encrypt_size(size_t *counter, size_t size)
{
  size_t sum;

  if (!INT_ADD_OK(*counter, size, &sum) ||
      sum > AES_GCM_ENCRYPT_MAX_BYTES) {
    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
  }
  *counter = sum;

  return 0;
}

static void _stream_encrypt(struct nettle_cipher_ctx *ctx, size_t length,
          uint8_t *dst, const uint8_t *src)
{
  ctx->cipher->encrypt_block(ctx->ctx_ptr, length, dst, src);
}

static void _stream_decrypt(struct nettle_cipher_ctx *ctx, size_t length,
          uint8_t *dst, const uint8_t *src)
{
  ctx->cipher->decrypt_block(ctx->ctx_ptr, length, dst, src);
}

static void _cbc_encrypt(struct nettle_cipher_ctx *ctx, size_t length,
       uint8_t *dst, const uint8_t *src)
{
  cbc_encrypt(ctx->ctx_ptr, ctx->cipher->encrypt_block, ctx->iv_size,
        ctx->iv, length, dst, src);
}

static void _cbc_decrypt(struct nettle_cipher_ctx *ctx, size_t length,
       uint8_t *dst, const uint8_t *src)
{
  cbc_decrypt(ctx->ctx_ptr, ctx->cipher->decrypt_block, ctx->iv_size,
        ctx->iv, length, dst, src);
}

#if ENABLE_GOST
struct magma_acpkm_ctx {
  uint8_t iv[MAGMA_BLOCK_SIZE];
  struct acpkm_ctx ctx;
  struct magma_ctx cipher;
};

struct kuznyechik_acpkm_ctx {
  uint8_t iv[KUZNYECHIK_BLOCK_SIZE];
  struct acpkm_ctx ctx;
  struct kuznyechik_ctx cipher;
};

static void _cfb_encrypt(struct nettle_cipher_ctx *ctx, size_t length,
       uint8_t *dst, const uint8_t *src)
{
  cfb_encrypt(ctx->ctx_ptr, ctx->cipher->encrypt_block, ctx->iv_size,
        ctx->iv, length, dst, src);
}

static void _cfb_decrypt(struct nettle_cipher_ctx *ctx, size_t length,
       uint8_t *dst, const uint8_t *src)
{
  cfb_decrypt(ctx->ctx_ptr, ctx->cipher->encrypt_block, ctx->iv_size,
        ctx->iv, length, dst, src);
}

static void _ctr_acpkm_crypt(struct nettle_cipher_ctx *ctx, size_t length,
           uint8_t *dst, const uint8_t *src)
{
  /* Use context-specific IV which comes as a first field */
  ctr_crypt(ctx->ctx_ptr, ctx->cipher->encrypt_block,
      ctx->cipher->block_size, ctx->ctx_ptr, length, dst, src);
}

static void _gost28147_set_key_tc26z(void *ctx, const uint8_t *key)
{
  gost28147_set_param(ctx, &gost28147_param_TC26_Z);
  gost28147_set_key(ctx, key);
}

static void _gost28147_set_key_cpa(void *ctx, const uint8_t *key)
{
  gost28147_set_param(ctx, &gost28147_param_CryptoPro_A);
  gost28147_set_key(ctx, key);
}

static void _gost28147_set_key_cpb(void *ctx, const uint8_t *key)
{
  gost28147_set_param(ctx, &gost28147_param_CryptoPro_B);
  gost28147_set_key(ctx, key);
}

static void _gost28147_set_key_cpc(void *ctx, const uint8_t *key)
{
  gost28147_set_param(ctx, &gost28147_param_CryptoPro_C);
  gost28147_set_key(ctx, key);
}

static void _gost28147_set_key_cpd(void *ctx, const uint8_t *key)
{
  gost28147_set_param(ctx, &gost28147_param_CryptoPro_D);
  gost28147_set_key(ctx, key);
}

static void _gost28147_cnt_set_key_tc26z(void *ctx, const uint8_t *key)
{
  gost28147_cnt_init(ctx, key, &gost28147_param_TC26_Z);
}

static void _gost28147_cnt_set_nonce(void *ctx, size_t length,
             const uint8_t *nonce)
{
  gost28147_cnt_set_iv(ctx, nonce);
}

static void _gost28147_cnt_crypt(struct nettle_cipher_ctx *ctx, size_t length,
         uint8_t *dst, const uint8_t *src)
{
  gost28147_cnt_crypt((void *)ctx->ctx_ptr, length, dst, src);
}

static void _magma_acpkm_crypt(struct magma_acpkm_ctx *ctx, size_t length,
             uint8_t *dst, const uint8_t *src)
{
  acpkm_crypt(&ctx->ctx, &ctx->cipher,
        (nettle_cipher_func *)magma_encrypt,
        (nettle_set_key_func *)magma_set_key, length, dst, src);
}

static void _kuznyechik_acpkm_crypt(struct kuznyechik_acpkm_ctx *ctx,
            size_t length, uint8_t *dst,
            const uint8_t *src)
{
  acpkm_crypt(&ctx->ctx, &ctx->cipher,
        (nettle_cipher_func *)kuznyechik_encrypt,
        (nettle_set_key_func *)kuznyechik_set_key, length, dst,
        src);
}

static void _magma_ctr_acpkm_set_key(struct magma_acpkm_ctx *ctx,
             const uint8_t *key)
{
  magma_set_key(&ctx->cipher, key);
  ctx->ctx.pos = 0;
  ctx->ctx.N = 1024;
}

static void _magma_ctr_acpkm_set_iv(struct magma_acpkm_ctx *ctx, size_t length,
            const uint8_t *iv)
{
  memcpy(ctx->iv, iv, length);
  memset(ctx->iv + length, 0, MAGMA_BLOCK_SIZE - length);
}

static void _kuznyechik_ctr_acpkm_set_key(struct kuznyechik_acpkm_ctx *ctx,
            const uint8_t *key)
{
  kuznyechik_set_key(&ctx->cipher, key);
  ctx->ctx.pos = 0;
  ctx->ctx.N = 4096;
}

static void _kuznyechik_ctr_acpkm_set_iv(struct kuznyechik_acpkm_ctx *ctx,
           size_t length, const uint8_t *iv)
{
  memcpy(ctx->iv, iv, length);
  memset(ctx->iv + length, 0, KUZNYECHIK_BLOCK_SIZE - length);
}
#endif

static void _ccm_encrypt(struct nettle_cipher_ctx *ctx, size_t nonce_size,
       const void *nonce, size_t auth_size, const void *auth,
       size_t tag_size, size_t length, uint8_t *dst,
       const uint8_t *src)
{
  ccm_encrypt_message((void *)ctx->ctx_ptr, ctx->cipher->encrypt_block,
          nonce_size, nonce, auth_size, auth, tag_size,
          length, dst, src);
}

static int _ccm_decrypt(struct nettle_cipher_ctx *ctx, size_t nonce_size,
      const void *nonce, size_t auth_size, const void *auth,
      size_t tag_size, size_t length, uint8_t *dst,
      const uint8_t *src)
{
  return ccm_decrypt_message((void *)ctx->ctx_ptr,
           ctx->cipher->encrypt_block, nonce_size,
           nonce, auth_size, auth, tag_size, length,
           dst, src);
}

static void _siv_cmac_aes128_encrypt_message(struct nettle_cipher_ctx *ctx,
               size_t nonce_size,
               const void *nonce,
               size_t auth_size, const void *auth,
               size_t tag_size, size_t length,
               uint8_t *dst, const uint8_t *src)
{
  siv_cmac_aes128_encrypt_message((void *)ctx->ctx_ptr, nonce_size, nonce,
          auth_size, auth, length, dst, src);
}

static int _siv_cmac_aes128_decrypt_message(struct nettle_cipher_ctx *ctx,
              size_t nonce_size,
              const void *nonce, size_t auth_size,
              const void *auth, size_t tag_size,
              size_t length, uint8_t *dst,
              const uint8_t *src)
{
  return siv_cmac_aes128_decrypt_message((void *)ctx->ctx_ptr, nonce_size,
                 nonce, auth_size, auth, length,
                 dst, src);
}

static void _siv_cmac_aes256_encrypt_message(struct nettle_cipher_ctx *ctx,
               size_t nonce_size,
               const void *nonce,
               size_t auth_size, const void *auth,
               size_t tag_size, size_t length,
               uint8_t *dst, const uint8_t *src)
{
  siv_cmac_aes256_encrypt_message((void *)ctx->ctx_ptr, nonce_size, nonce,
          auth_size, auth, length, dst, src);
}

static int _siv_cmac_aes256_decrypt_message(struct nettle_cipher_ctx *ctx,
              size_t nonce_size,
              const void *nonce, size_t auth_size,
              const void *auth, size_t tag_size,
              size_t length, uint8_t *dst,
              const uint8_t *src)
{
  return siv_cmac_aes256_decrypt_message((void *)ctx->ctx_ptr, nonce_size,
                 nonce, auth_size, auth, length,
                 dst, src);
}

static void _siv_gcm_aes128_encrypt_message(struct nettle_cipher_ctx *ctx,
              size_t nonce_size,
              const void *nonce, size_t auth_size,
              const void *auth, size_t tag_size,
              size_t length, uint8_t *dst,
              const uint8_t *src)
{
  siv_gcm_aes128_encrypt_message((void *)ctx->ctx_ptr, nonce_size, nonce,
               auth_size, auth, length, dst, src);
}

static int _siv_gcm_aes128_decrypt_message(struct nettle_cipher_ctx *ctx,
             size_t nonce_size, const void *nonce,
             size_t auth_size, const void *auth,
             size_t tag_size, size_t length,
             uint8_t *dst, const uint8_t *src)
{
  return siv_gcm_aes128_decrypt_message((void *)ctx->ctx_ptr, nonce_size,
                nonce, auth_size, auth, length,
                dst, src);
}

static void _siv_gcm_aes256_encrypt_message(struct nettle_cipher_ctx *ctx,
              size_t nonce_size,
              const void *nonce, size_t auth_size,
              const void *auth, size_t tag_size,
              size_t length, uint8_t *dst,
              const uint8_t *src)
{
  siv_gcm_aes256_encrypt_message((void *)ctx->ctx_ptr, nonce_size, nonce,
               auth_size, auth, length, dst, src);
}

static int _siv_gcm_aes256_decrypt_message(struct nettle_cipher_ctx *ctx,
             size_t nonce_size, const void *nonce,
             size_t auth_size, const void *auth,
             size_t tag_size, size_t length,
             uint8_t *dst, const uint8_t *src)
{
  return siv_gcm_aes256_decrypt_message((void *)ctx->ctx_ptr, nonce_size,
                nonce, auth_size, auth, length,
                dst, src);
}

static void _chacha_set_nonce(struct chacha_ctx *ctx, size_t length,
            const uint8_t *nonce)
{
  chacha_set_nonce(ctx, nonce + CHACHA_COUNTER_SIZE);
  chacha_set_counter(ctx, nonce);
}

static void _chacha_set_nonce96(struct chacha_ctx *ctx, size_t length,
        const uint8_t *nonce)
{
  chacha_set_nonce96(ctx, nonce + CHACHA_COUNTER32_SIZE);
  chacha_set_counter32(ctx, nonce);
}

static void _chacha_poly1305_set_nonce(struct chacha_poly1305_ctx *ctx,
               size_t length, const uint8_t *nonce)
{
  chacha_poly1305_set_nonce(ctx, nonce);
}

struct gcm_cast_st {
  struct gcm_key key;
  struct gcm_ctx gcm;
  unsigned long xx[1];
};
#define GCM_CTX_GET_KEY(ptr) (&((struct gcm_cast_st *)ptr)->key)
#define GCM_CTX_GET_CTX(ptr) (&((struct gcm_cast_st *)ptr)->gcm)
#define GCM_CTX_GET_CIPHER(ptr) ((void *)&((struct gcm_cast_st *)ptr)->xx)

static void _gcm_encrypt(struct nettle_cipher_ctx *ctx, size_t length,
       uint8_t *dst, const uint8_t *src)
{
  gcm_encrypt(GCM_CTX_GET_CTX(ctx->ctx_ptr),
        GCM_CTX_GET_KEY(ctx->ctx_ptr),
        GCM_CTX_GET_CIPHER(ctx->ctx_ptr),
        ctx->cipher->encrypt_block, length, dst, src);
}

static void _gcm_decrypt(struct nettle_cipher_ctx *ctx, size_t length,
       uint8_t *dst, const uint8_t *src)
{
  gcm_decrypt(GCM_CTX_GET_CTX(ctx->ctx_ptr),
        GCM_CTX_GET_KEY(ctx->ctx_ptr),
        GCM_CTX_GET_CIPHER(ctx->ctx_ptr),
        ctx->cipher->encrypt_block, length, dst, src);
}

static void _des_set_key(struct des_ctx *ctx, const uint8_t *key)
{
  des_set_key(ctx, key);
}

static void _des3_set_key(struct des3_ctx *ctx, const uint8_t *key)
{
  des3_set_key(ctx, key);
}

static void _cfb8_encrypt(struct nettle_cipher_ctx *ctx, size_t length,
        uint8_t *dst, const uint8_t *src)
{
  cfb8_encrypt(ctx->ctx_ptr, ctx->cipher->encrypt_block, ctx->iv_size,
         ctx->iv, length, dst, src);
}

static void _cfb8_decrypt(struct nettle_cipher_ctx *ctx, size_t length,
        uint8_t *dst, const uint8_t *src)
{
  cfb8_decrypt(ctx->ctx_ptr, ctx->cipher->encrypt_block, ctx->iv_size,
         ctx->iv, length, dst, src);
}

static void _xts_aes128_encrypt(struct nettle_cipher_ctx *ctx, size_t length,
        uint8_t *dst, const uint8_t *src)
{
  xts_aes128_encrypt_message(ctx->ctx_ptr, ctx->iv, length, dst, src);
}

static void _xts_aes128_decrypt(struct nettle_cipher_ctx *ctx, size_t length,
        uint8_t *dst, const uint8_t *src)
{
  xts_aes128_decrypt_message(ctx->ctx_ptr, ctx->iv, length, dst, src);
}

static void _xts_aes256_encrypt(struct nettle_cipher_ctx *ctx, size_t length,
        uint8_t *dst, const uint8_t *src)
{
  xts_aes256_encrypt_message(ctx->ctx_ptr, ctx->iv, length, dst, src);
}

static void _xts_aes256_decrypt(struct nettle_cipher_ctx *ctx, size_t length,
        uint8_t *dst, const uint8_t *src)
{
  xts_aes256_decrypt_message(ctx->ctx_ptr, ctx->iv, length, dst, src);
}

static const struct nettle_cipher_st builtin_ciphers[] = {
  {
    .algo = GNUTLS_CIPHER_AES_128_GCM,
    .block_size = AES_BLOCK_SIZE,
    .key_size = AES128_KEY_SIZE,
    .encrypt_block = (nettle_cipher_func *)aes128_encrypt,
    .decrypt_block = (nettle_cipher_func *)aes128_decrypt,

    .ctx_size = sizeof(struct gcm_aes128_ctx),
    .encrypt = _gcm_encrypt,
    .decrypt = _gcm_decrypt,
    .set_encrypt_key = (nettle_set_key_func *)gcm_aes128_set_key,
    .set_decrypt_key = (nettle_set_key_func *)gcm_aes128_set_key,

    .tag = (nettle_hash_digest_func *)gcm_aes128_digest,
    .auth = (nettle_hash_update_func *)gcm_aes128_update,
    .set_iv = (setiv_func)gcm_aes128_set_iv,
    .max_iv_size = GCM_IV_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_AES_192_GCM,
    .block_size = AES_BLOCK_SIZE,
    .key_size = AES192_KEY_SIZE,
    .encrypt_block = (nettle_cipher_func *)aes192_encrypt,
    .decrypt_block = (nettle_cipher_func *)aes192_decrypt,

    .ctx_size = sizeof(struct gcm_aes192_ctx),
    .encrypt = _gcm_encrypt,
    .decrypt = _gcm_decrypt,
    .set_encrypt_key = (nettle_set_key_func *)gcm_aes192_set_key,
    .set_decrypt_key = (nettle_set_key_func *)gcm_aes192_set_key,

    .tag = (nettle_hash_digest_func *)gcm_aes192_digest,
    .auth = (nettle_hash_update_func *)gcm_aes192_update,
    .set_iv = (setiv_func)gcm_aes192_set_iv,
    .max_iv_size = GCM_IV_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_AES_256_GCM,
    .block_size = AES_BLOCK_SIZE,
    .key_size = AES256_KEY_SIZE,
    .encrypt_block = (nettle_cipher_func *)aes256_encrypt,
    .decrypt_block = (nettle_cipher_func *)aes256_decrypt,

    .ctx_size = sizeof(struct gcm_aes256_ctx),
    .encrypt = _gcm_encrypt,
    .decrypt = _gcm_decrypt,
    .set_encrypt_key = (nettle_set_key_func *)gcm_aes256_set_key,
    .set_decrypt_key = (nettle_set_key_func *)gcm_aes256_set_key,

    .tag = (nettle_hash_digest_func *)gcm_aes256_digest,
    .auth = (nettle_hash_update_func *)gcm_aes256_update,
    .set_iv = (setiv_func)gcm_aes256_set_iv,
    .max_iv_size = GCM_IV_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_AES_128_CCM,
    .block_size = AES_BLOCK_SIZE,
    .key_size = AES128_KEY_SIZE,
    .encrypt_block = (nettle_cipher_func *)aes128_encrypt,
    .decrypt_block = (nettle_cipher_func *)aes128_decrypt,

    .ctx_size = sizeof(struct aes128_ctx),
    .aead_encrypt = _ccm_encrypt,
    .aead_decrypt = _ccm_decrypt,
    .set_encrypt_key =
      (nettle_set_key_func *)aes128_set_encrypt_key,
    .set_decrypt_key =
      (nettle_set_key_func *)aes128_set_encrypt_key,
    .max_iv_size = CCM_MAX_NONCE_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_AES_128_CCM_8,
    .block_size = AES_BLOCK_SIZE,
    .key_size = AES128_KEY_SIZE,
    .encrypt_block = (nettle_cipher_func *)aes128_encrypt,
    .decrypt_block = (nettle_cipher_func *)aes128_decrypt,

    .ctx_size = sizeof(struct aes128_ctx),
    .aead_encrypt = _ccm_encrypt,
    .aead_decrypt = _ccm_decrypt,
    .set_encrypt_key =
      (nettle_set_key_func *)aes128_set_encrypt_key,
    .set_decrypt_key =
      (nettle_set_key_func *)aes128_set_encrypt_key,
    .max_iv_size = CCM_MAX_NONCE_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_AES_256_CCM,
    .block_size = AES_BLOCK_SIZE,
    .key_size = AES256_KEY_SIZE,
    .encrypt_block = (nettle_cipher_func *)aes256_encrypt,
    .decrypt_block = (nettle_cipher_func *)aes256_decrypt,

    .ctx_size = sizeof(struct aes256_ctx),
    .aead_encrypt = _ccm_encrypt,
    .aead_decrypt = _ccm_decrypt,
    .set_encrypt_key =
      (nettle_set_key_func *)aes256_set_encrypt_key,
    .set_decrypt_key =
      (nettle_set_key_func *)aes256_set_encrypt_key,
    .max_iv_size = CCM_MAX_NONCE_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_AES_256_CCM_8,
    .block_size = AES_BLOCK_SIZE,
    .key_size = AES256_KEY_SIZE,
    .encrypt_block = (nettle_cipher_func *)aes256_encrypt,
    .decrypt_block = (nettle_cipher_func *)aes256_decrypt,

    .ctx_size = sizeof(struct aes256_ctx),
    .aead_encrypt = _ccm_encrypt,
    .aead_decrypt = _ccm_decrypt,
    .set_encrypt_key =
      (nettle_set_key_func *)aes256_set_encrypt_key,
    .set_decrypt_key =
      (nettle_set_key_func *)aes256_set_encrypt_key,
    .max_iv_size = CCM_MAX_NONCE_SIZE,
  },
  { .algo = GNUTLS_CIPHER_CAMELLIA_128_GCM,
    .block_size = CAMELLIA_BLOCK_SIZE,
    .key_size = CAMELLIA128_KEY_SIZE,
    .encrypt_block = (nettle_cipher_func *)camellia128_crypt,
    .decrypt_block = (nettle_cipher_func *)camellia128_crypt,

    .ctx_size = sizeof(struct gcm_camellia128_ctx),
    .encrypt = _gcm_encrypt,
    .decrypt = _gcm_decrypt,
    .set_encrypt_key = (nettle_set_key_func *)gcm_camellia128_set_key,
    .set_decrypt_key = (nettle_set_key_func *)gcm_camellia128_set_key,
    .tag = (nettle_hash_digest_func *)gcm_camellia128_digest,
    .auth = (nettle_hash_update_func *)gcm_camellia128_update,
    .max_iv_size = GCM_IV_SIZE,
    .set_iv = (setiv_func)gcm_camellia128_set_iv },
  { .algo = GNUTLS_CIPHER_CAMELLIA_256_GCM,
    .block_size = CAMELLIA_BLOCK_SIZE,
    .key_size = CAMELLIA256_KEY_SIZE,
    .encrypt_block = (nettle_cipher_func *)camellia256_crypt,
    .decrypt_block = (nettle_cipher_func *)camellia256_crypt,

    .ctx_size = sizeof(struct gcm_camellia256_ctx),
    .encrypt = _gcm_encrypt,
    .decrypt = _gcm_decrypt,
    .set_encrypt_key = (nettle_set_key_func *)gcm_camellia256_set_key,
    .set_decrypt_key = (nettle_set_key_func *)gcm_camellia256_set_key,
    .tag = (nettle_hash_digest_func *)gcm_camellia256_digest,
    .auth = (nettle_hash_update_func *)gcm_camellia256_update,
    .max_iv_size = GCM_IV_SIZE,
    .set_iv = (setiv_func)gcm_camellia256_set_iv },
  {
    .algo = GNUTLS_CIPHER_AES_128_CBC,
    .block_size = AES_BLOCK_SIZE,
    .key_size = AES128_KEY_SIZE,
    .encrypt_block = (nettle_cipher_func *)aes128_encrypt,
    .decrypt_block = (nettle_cipher_func *)aes128_decrypt,

    .ctx_size = sizeof(
      struct CBC_CTX(struct aes128_ctx, AES_BLOCK_SIZE)),
    .encrypt = _cbc_encrypt,
    .decrypt = _cbc_decrypt,
    .set_encrypt_key =
      (nettle_set_key_func *)aes128_set_encrypt_key,
    .set_decrypt_key =
      (nettle_set_key_func *)aes128_set_decrypt_key,
    .max_iv_size = AES_BLOCK_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_AES_192_CBC,
    .block_size = AES_BLOCK_SIZE,
    .key_size = AES192_KEY_SIZE,
    .encrypt_block = (nettle_cipher_func *)aes192_encrypt,
    .decrypt_block = (nettle_cipher_func *)aes192_decrypt,

    .ctx_size = sizeof(
      struct CBC_CTX(struct aes192_ctx, AES_BLOCK_SIZE)),
    .encrypt = _cbc_encrypt,
    .decrypt = _cbc_decrypt,
    .set_encrypt_key =
      (nettle_set_key_func *)aes192_set_encrypt_key,
    .set_decrypt_key =
      (nettle_set_key_func *)aes192_set_decrypt_key,
    .max_iv_size = AES_BLOCK_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_AES_256_CBC,
    .block_size = AES_BLOCK_SIZE,
    .key_size = AES256_KEY_SIZE,
    .encrypt_block = (nettle_cipher_func *)aes256_encrypt,
    .decrypt_block = (nettle_cipher_func *)aes256_decrypt,

    .ctx_size = sizeof(
      struct CBC_CTX(struct aes256_ctx, AES_BLOCK_SIZE)),
    .encrypt = _cbc_encrypt,
    .decrypt = _cbc_decrypt,
    .set_encrypt_key =
      (nettle_set_key_func *)aes256_set_encrypt_key,
    .set_decrypt_key =
      (nettle_set_key_func *)aes256_set_decrypt_key,
    .max_iv_size = AES_BLOCK_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_CAMELLIA_128_CBC,
    .block_size = CAMELLIA_BLOCK_SIZE,
    .key_size = CAMELLIA128_KEY_SIZE,
    .encrypt_block = (nettle_cipher_func *)camellia128_crypt,
    .decrypt_block = (nettle_cipher_func *)camellia128_crypt,

    .ctx_size = sizeof(struct CBC_CTX(struct camellia128_ctx,
              CAMELLIA_BLOCK_SIZE)),
    .encrypt = _cbc_encrypt,
    .decrypt = _cbc_decrypt,
    .set_encrypt_key =
      (nettle_set_key_func *)camellia128_set_encrypt_key,
    .set_decrypt_key =
      (nettle_set_key_func *)camellia128_set_decrypt_key,
    .max_iv_size = CAMELLIA_BLOCK_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_CAMELLIA_192_CBC,
    .block_size = CAMELLIA_BLOCK_SIZE,
    .key_size = CAMELLIA192_KEY_SIZE,
    .encrypt_block = (nettle_cipher_func *)camellia192_crypt,
    .decrypt_block = (nettle_cipher_func *)camellia192_crypt,

    .ctx_size = sizeof(struct CBC_CTX(struct camellia192_ctx,
              CAMELLIA_BLOCK_SIZE)),
    .encrypt = _cbc_encrypt,
    .decrypt = _cbc_decrypt,
    .set_encrypt_key =
      (nettle_set_key_func *)camellia192_set_encrypt_key,
    .set_decrypt_key =
      (nettle_set_key_func *)camellia192_set_decrypt_key,
    .max_iv_size = CAMELLIA_BLOCK_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_CAMELLIA_256_CBC,
    .block_size = CAMELLIA_BLOCK_SIZE,
    .key_size = CAMELLIA256_KEY_SIZE,
    .encrypt_block = (nettle_cipher_func *)camellia256_crypt,
    .decrypt_block = (nettle_cipher_func *)camellia256_crypt,

    .ctx_size = sizeof(struct CBC_CTX(struct camellia256_ctx,
              CAMELLIA_BLOCK_SIZE)),
    .encrypt = _cbc_encrypt,
    .decrypt = _cbc_decrypt,
    .set_encrypt_key =
      (nettle_set_key_func *)camellia256_set_encrypt_key,
    .set_decrypt_key =
      (nettle_set_key_func *)camellia256_set_decrypt_key,
    .max_iv_size = CAMELLIA_BLOCK_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_RC2_40_CBC,
    .block_size = ARCTWO_BLOCK_SIZE,
    .key_size = 5,
    .encrypt_block = (nettle_cipher_func *)arctwo_encrypt,
    .decrypt_block = (nettle_cipher_func *)arctwo_decrypt,

    .ctx_size = sizeof(
      struct CBC_CTX(struct arctwo_ctx, ARCTWO_BLOCK_SIZE)),
    .encrypt = _cbc_encrypt,
    .decrypt = _cbc_decrypt,
    .set_encrypt_key = (nettle_set_key_func *)arctwo40_set_key,
    .set_decrypt_key = (nettle_set_key_func *)arctwo40_set_key,
    .max_iv_size = ARCTWO_BLOCK_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_DES_CBC,
    .block_size = DES_BLOCK_SIZE,
    .key_size = DES_KEY_SIZE,
    .encrypt_block = (nettle_cipher_func *)des_encrypt,
    .decrypt_block = (nettle_cipher_func *)des_decrypt,

    .ctx_size =
      sizeof(struct CBC_CTX(struct des_ctx, DES_BLOCK_SIZE)),
    .encrypt = _cbc_encrypt,
    .decrypt = _cbc_decrypt,
    .set_encrypt_key = (nettle_set_key_func *)_des_set_key,
    .set_decrypt_key = (nettle_set_key_func *)_des_set_key,
    .max_iv_size = DES_BLOCK_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_3DES_CBC,
    .block_size = DES3_BLOCK_SIZE,
    .key_size = DES3_KEY_SIZE,
    .encrypt_block = (nettle_cipher_func *)des3_encrypt,
    .decrypt_block = (nettle_cipher_func *)des3_decrypt,

    .ctx_size = sizeof(
      struct CBC_CTX(struct des3_ctx, DES3_BLOCK_SIZE)),
    .encrypt = _cbc_encrypt,
    .decrypt = _cbc_decrypt,
    .set_encrypt_key = (nettle_set_key_func *)_des3_set_key,
    .set_decrypt_key = (nettle_set_key_func *)_des3_set_key,
    .max_iv_size = DES_BLOCK_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_ARCFOUR_128,
    .block_size = 1,
    .key_size = 0,
    .encrypt_block = (nettle_cipher_func *)arcfour_crypt,
    .decrypt_block = (nettle_cipher_func *)arcfour_crypt,

    .ctx_size = sizeof(struct arcfour_ctx),
    .encrypt = _stream_encrypt,
    .decrypt = _stream_encrypt,
    .gen_set_key = (gen_setkey_func)arcfour_set_key,
    .set_encrypt_key = (nettle_set_key_func *)arcfour128_set_key,
    .set_decrypt_key = (nettle_set_key_func *)arcfour128_set_key,
  },
  {
    .algo = GNUTLS_CIPHER_SALSA20_256,
    .block_size = 1,
    .key_size = SALSA20_256_KEY_SIZE,
    .encrypt_block = (nettle_cipher_func *)salsa20_crypt,
    .decrypt_block = (nettle_cipher_func *)salsa20_crypt,

    .ctx_size = sizeof(struct salsa20_ctx),
    .encrypt = _stream_encrypt,
    .decrypt = _stream_encrypt,
    .set_encrypt_key = (nettle_set_key_func *)salsa20_256_set_key,
    .set_decrypt_key = (nettle_set_key_func *)salsa20_256_set_key,
    .max_iv_size = SALSA20_NONCE_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_ESTREAM_SALSA20_256,
    .block_size = 1,
    .key_size = SALSA20_256_KEY_SIZE,
    .encrypt_block = (nettle_cipher_func *)salsa20r12_crypt,
    .decrypt_block = (nettle_cipher_func *)salsa20r12_crypt,

    .ctx_size = sizeof(struct salsa20_ctx),
    .encrypt = _stream_encrypt,
    .decrypt = _stream_encrypt,
    .set_encrypt_key = (nettle_set_key_func *)salsa20_256_set_key,
    .set_decrypt_key = (nettle_set_key_func *)salsa20_256_set_key,
    .max_iv_size = SALSA20_NONCE_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_CHACHA20_32,
    .block_size = 1,
    .key_size = CHACHA_KEY_SIZE,
    .encrypt_block = (nettle_cipher_func *)chacha_crypt32,
    .decrypt_block = (nettle_cipher_func *)chacha_crypt32,

    .ctx_size = sizeof(struct chacha_ctx),
    .encrypt = _stream_encrypt,
    .decrypt = _stream_encrypt,
    .set_encrypt_key = (nettle_set_key_func *)chacha_set_key,
    .set_decrypt_key = (nettle_set_key_func *)chacha_set_key,
    .set_iv = (setiv_func)_chacha_set_nonce96,
    /* we allow setting the initial block counter as part of nonce */
    .max_iv_size = CHACHA_NONCE96_SIZE + CHACHA_COUNTER32_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_CHACHA20_64,
    .block_size = 1,
    .key_size = CHACHA_KEY_SIZE,
    .encrypt_block = (nettle_cipher_func *)chacha_crypt,
    .decrypt_block = (nettle_cipher_func *)chacha_crypt,

    .ctx_size = sizeof(struct chacha_ctx),
    .encrypt = _stream_encrypt,
    .decrypt = _stream_encrypt,
    .set_encrypt_key = (nettle_set_key_func *)chacha_set_key,
    .set_decrypt_key = (nettle_set_key_func *)chacha_set_key,
    .set_iv = (setiv_func)_chacha_set_nonce,
    /* we allow setting the initial block counter as part of nonce */
    .max_iv_size = CHACHA_NONCE_SIZE + CHACHA_COUNTER_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_CHACHA20_POLY1305,
    .block_size = CHACHA_POLY1305_BLOCK_SIZE,
    .key_size = CHACHA_POLY1305_KEY_SIZE,

    .ctx_size = sizeof(struct chacha_poly1305_ctx),
    .encrypt_block = (nettle_cipher_func *)chacha_poly1305_encrypt,
    .decrypt_block = (nettle_cipher_func *)chacha_poly1305_decrypt,
    .encrypt = _stream_encrypt,
    .decrypt = _stream_decrypt,
    .auth = (nettle_hash_update_func *)chacha_poly1305_update,
    .tag = (nettle_hash_digest_func *)chacha_poly1305_digest,
    .set_encrypt_key =
      (nettle_set_key_func *)chacha_poly1305_set_key,
    .set_decrypt_key =
      (nettle_set_key_func *)chacha_poly1305_set_key,
    .set_iv = (setiv_func)_chacha_poly1305_set_nonce,
    .max_iv_size = CHACHA_POLY1305_NONCE_SIZE,
  },
#if ENABLE_GOST
  {
    .algo = GNUTLS_CIPHER_GOST28147_TC26Z_CFB,
    .block_size = GOST28147_BLOCK_SIZE,
    .key_size = GOST28147_KEY_SIZE,
    .encrypt_block =
      (nettle_cipher_func *)gost28147_encrypt_for_cfb,
    .decrypt_block =
      (nettle_cipher_func *)gost28147_encrypt_for_cfb,

    .ctx_size = sizeof(struct CFB_CTX(struct gost28147_ctx,
              GOST28147_BLOCK_SIZE)),
    .encrypt = _cfb_encrypt,
    .decrypt = _cfb_decrypt,
    .set_encrypt_key = _gost28147_set_key_tc26z,
    .set_decrypt_key = _gost28147_set_key_tc26z,
  },
  {
    .algo = GNUTLS_CIPHER_GOST28147_CPA_CFB,
    .block_size = GOST28147_BLOCK_SIZE,
    .key_size = GOST28147_KEY_SIZE,
    .encrypt_block =
      (nettle_cipher_func *)gost28147_encrypt_for_cfb,
    .decrypt_block =
      (nettle_cipher_func *)gost28147_encrypt_for_cfb,

    .ctx_size = sizeof(struct CFB_CTX(struct gost28147_ctx,
              GOST28147_BLOCK_SIZE)),
    .encrypt = _cfb_encrypt,
    .decrypt = _cfb_decrypt,
    .set_encrypt_key = _gost28147_set_key_cpa,
    .set_decrypt_key = _gost28147_set_key_cpa,
  },
  {
    .algo = GNUTLS_CIPHER_GOST28147_CPB_CFB,
    .block_size = GOST28147_BLOCK_SIZE,
    .key_size = GOST28147_KEY_SIZE,
    .encrypt_block =
      (nettle_cipher_func *)gost28147_encrypt_for_cfb,
    .decrypt_block =
      (nettle_cipher_func *)gost28147_encrypt_for_cfb,

    .ctx_size = sizeof(struct CFB_CTX(struct gost28147_ctx,
              GOST28147_BLOCK_SIZE)),
    .encrypt = _cfb_encrypt,
    .decrypt = _cfb_decrypt,
    .set_encrypt_key = _gost28147_set_key_cpb,
    .set_decrypt_key = _gost28147_set_key_cpb,
  },
  {
    .algo = GNUTLS_CIPHER_GOST28147_CPC_CFB,
    .block_size = GOST28147_BLOCK_SIZE,
    .key_size = GOST28147_KEY_SIZE,
    .encrypt_block =
      (nettle_cipher_func *)gost28147_encrypt_for_cfb,
    .decrypt_block =
      (nettle_cipher_func *)gost28147_encrypt_for_cfb,

    .ctx_size = sizeof(struct CFB_CTX(struct gost28147_ctx,
              GOST28147_BLOCK_SIZE)),
    .encrypt = _cfb_encrypt,
    .decrypt = _cfb_decrypt,
    .set_encrypt_key = _gost28147_set_key_cpc,
    .set_decrypt_key = _gost28147_set_key_cpc,
  },
  {
    .algo = GNUTLS_CIPHER_GOST28147_CPD_CFB,
    .block_size = GOST28147_BLOCK_SIZE,
    .key_size = GOST28147_KEY_SIZE,
    .encrypt_block =
      (nettle_cipher_func *)gost28147_encrypt_for_cfb,
    .decrypt_block =
      (nettle_cipher_func *)gost28147_encrypt_for_cfb,

    .ctx_size = sizeof(struct CFB_CTX(struct gost28147_ctx,
              GOST28147_BLOCK_SIZE)),
    .encrypt = _cfb_encrypt,
    .decrypt = _cfb_decrypt,
    .set_encrypt_key = _gost28147_set_key_cpd,
    .set_decrypt_key = _gost28147_set_key_cpd,
  },
  {
    .algo = GNUTLS_CIPHER_GOST28147_TC26Z_CNT,
    .block_size = GOST28147_BLOCK_SIZE,
    .key_size = GOST28147_KEY_SIZE,
    .encrypt_block =
      (nettle_cipher_func *)gost28147_encrypt, /* unused */
    .decrypt_block =
      (nettle_cipher_func *)gost28147_decrypt, /* unused */

    .ctx_size = sizeof(struct gost28147_cnt_ctx),
    .encrypt = _gost28147_cnt_crypt,
    .decrypt = _gost28147_cnt_crypt,
    .set_encrypt_key = _gost28147_cnt_set_key_tc26z,
    .set_decrypt_key = _gost28147_cnt_set_key_tc26z,
    .set_iv = (setiv_func)_gost28147_cnt_set_nonce,
  },
  {
    .algo = GNUTLS_CIPHER_MAGMA_CTR_ACPKM,
    .block_size = MAGMA_BLOCK_SIZE,
    .key_size = MAGMA_KEY_SIZE,
    .encrypt_block = (nettle_cipher_func *)_magma_acpkm_crypt,
    .decrypt_block = (nettle_cipher_func *)_magma_acpkm_crypt,

    .ctx_size = sizeof(struct magma_acpkm_ctx),
    .encrypt = _ctr_acpkm_crypt,
    .decrypt = _ctr_acpkm_crypt,
    .set_encrypt_key =
      (nettle_set_key_func *)_magma_ctr_acpkm_set_key,
    .set_decrypt_key =
      (nettle_set_key_func *)_magma_ctr_acpkm_set_key,
    .set_iv = (setiv_func)_magma_ctr_acpkm_set_iv,
  },
  {
    .algo = GNUTLS_CIPHER_KUZNYECHIK_CTR_ACPKM,
    .block_size = KUZNYECHIK_BLOCK_SIZE,
    .key_size = KUZNYECHIK_KEY_SIZE,
    .encrypt_block = (nettle_cipher_func *)_kuznyechik_acpkm_crypt,
    .decrypt_block = (nettle_cipher_func *)_kuznyechik_acpkm_crypt,

    .ctx_size = sizeof(struct kuznyechik_acpkm_ctx),
    .encrypt = _ctr_acpkm_crypt,
    .decrypt = _ctr_acpkm_crypt,
    .set_encrypt_key =
      (nettle_set_key_func *)_kuznyechik_ctr_acpkm_set_key,
    .set_decrypt_key =
      (nettle_set_key_func *)_kuznyechik_ctr_acpkm_set_key,
    .set_iv = (setiv_func)_kuznyechik_ctr_acpkm_set_iv,
  },
#endif
  {
    .algo = GNUTLS_CIPHER_AES_128_CFB8,
    .block_size = AES_BLOCK_SIZE,
    .key_size = AES128_KEY_SIZE,
    .encrypt_block = (nettle_cipher_func *)aes128_encrypt,
    .decrypt_block = (nettle_cipher_func *)aes128_encrypt,

    .ctx_size = sizeof(
      struct CFB8_CTX(struct aes128_ctx, AES_BLOCK_SIZE)),
    .encrypt = _cfb8_encrypt,
    .decrypt = _cfb8_decrypt,
    .set_encrypt_key =
      (nettle_set_key_func *)aes128_set_encrypt_key,
    .set_decrypt_key =
      (nettle_set_key_func *)aes128_set_encrypt_key,
    .max_iv_size = AES_BLOCK_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_AES_192_CFB8,
    .block_size = AES_BLOCK_SIZE,
    .key_size = AES192_KEY_SIZE,
    .encrypt_block = (nettle_cipher_func *)aes192_encrypt,
    .decrypt_block = (nettle_cipher_func *)aes192_encrypt,

    .ctx_size = sizeof(
      struct CFB8_CTX(struct aes192_ctx, AES_BLOCK_SIZE)),
    .encrypt = _cfb8_encrypt,
    .decrypt = _cfb8_decrypt,
    .set_encrypt_key =
      (nettle_set_key_func *)aes192_set_encrypt_key,
    .set_decrypt_key =
      (nettle_set_key_func *)aes192_set_encrypt_key,
    .max_iv_size = AES_BLOCK_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_AES_256_CFB8,
    .block_size = AES_BLOCK_SIZE,
    .key_size = AES256_KEY_SIZE,
    .encrypt_block = (nettle_cipher_func *)aes256_encrypt,
    .decrypt_block = (nettle_cipher_func *)aes256_encrypt,

    .ctx_size = sizeof(
      struct CFB8_CTX(struct aes256_ctx, AES_BLOCK_SIZE)),
    .encrypt = _cfb8_encrypt,
    .decrypt = _cfb8_decrypt,
    .set_encrypt_key =
      (nettle_set_key_func *)aes256_set_encrypt_key,
    .set_decrypt_key =
      (nettle_set_key_func *)aes256_set_encrypt_key,
    .max_iv_size = AES_BLOCK_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_AES_128_XTS,
    .block_size = AES_BLOCK_SIZE,
    .key_size = AES128_KEY_SIZE * 2,

    .ctx_size = sizeof(struct xts_aes128_key),
    .encrypt = _xts_aes128_encrypt,
    .decrypt = _xts_aes128_decrypt,
    .set_encrypt_key =
      (nettle_set_key_func *)xts_aes128_set_encrypt_key,
    .set_decrypt_key =
      (nettle_set_key_func *)xts_aes128_set_decrypt_key,
    .max_iv_size = AES_BLOCK_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_AES_256_XTS,
    .block_size = AES_BLOCK_SIZE,
    .key_size = AES256_KEY_SIZE * 2,

    .ctx_size = sizeof(struct xts_aes256_key),
    .encrypt = _xts_aes256_encrypt,
    .decrypt = _xts_aes256_decrypt,
    .set_encrypt_key =
      (nettle_set_key_func *)xts_aes256_set_encrypt_key,
    .set_decrypt_key =
      (nettle_set_key_func *)xts_aes256_set_decrypt_key,
    .max_iv_size = AES_BLOCK_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_AES_128_SIV,
    .block_size = SIV_BLOCK_SIZE,
    .key_size = SIV_CMAC_AES128_KEY_SIZE,

    .ctx_size = sizeof(struct siv_cmac_aes128_ctx),
    .aead_encrypt =
      (aead_encrypt_func)_siv_cmac_aes128_encrypt_message,
    .aead_decrypt =
      (aead_decrypt_func)_siv_cmac_aes128_decrypt_message,
    .set_encrypt_key =
      (nettle_set_key_func *)siv_cmac_aes128_set_key,
    .set_decrypt_key =
      (nettle_set_key_func *)siv_cmac_aes128_set_key,
    .max_iv_size = SIV_DIGEST_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_AES_256_SIV,
    .block_size = SIV_BLOCK_SIZE,
    .key_size = SIV_CMAC_AES256_KEY_SIZE,

    .ctx_size = sizeof(struct siv_cmac_aes256_ctx),
    .aead_encrypt =
      (aead_encrypt_func)_siv_cmac_aes256_encrypt_message,
    .aead_decrypt =
      (aead_decrypt_func)_siv_cmac_aes256_decrypt_message,
    .set_encrypt_key =
      (nettle_set_key_func *)siv_cmac_aes256_set_key,
    .set_decrypt_key =
      (nettle_set_key_func *)siv_cmac_aes256_set_key,
    .max_iv_size = SIV_DIGEST_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_AES_128_SIV_GCM,
    .block_size = SIV_GCM_BLOCK_SIZE,
    .key_size = AES128_KEY_SIZE,

    .ctx_size = sizeof(struct aes128_ctx),
    .aead_encrypt =
      (aead_encrypt_func)_siv_gcm_aes128_encrypt_message,
    .aead_decrypt =
      (aead_decrypt_func)_siv_gcm_aes128_decrypt_message,
    .set_encrypt_key =
      (nettle_set_key_func *)aes128_set_encrypt_key,
    .set_decrypt_key =
      (nettle_set_key_func *)aes128_set_encrypt_key,
    .max_iv_size = SIV_GCM_NONCE_SIZE,
  },
  {
    .algo = GNUTLS_CIPHER_AES_256_SIV_GCM,
    .block_size = SIV_GCM_BLOCK_SIZE,
    .key_size = AES256_KEY_SIZE,

    .ctx_size = sizeof(struct aes256_ctx),
    .aead_encrypt =
      (aead_encrypt_func)_siv_gcm_aes256_encrypt_message,
    .aead_decrypt =
      (aead_decrypt_func)_siv_gcm_aes256_decrypt_message,
    .set_encrypt_key =
      (nettle_set_key_func *)aes256_set_encrypt_key,
    .set_decrypt_key =
      (nettle_set_key_func *)aes256_set_encrypt_key,
    .max_iv_size = SIV_GCM_NONCE_SIZE,
  },
};

static int wrap_nettle_cipher_exists(gnutls_cipher_algorithm_t algo)
{
  unsigned i;
  for (i = 0; i < sizeof(builtin_ciphers) / sizeof(builtin_ciphers[0]);
       i++) {
    if (algo == builtin_ciphers[i].algo) {
      return 1;
    }
  }
  return 0;
}

static int wrap_nettle_cipher_init(gnutls_cipher_algorithm_t algo, void **_ctx,
           int enc)
{
  struct nettle_cipher_ctx *ctx;
  uintptr_t cur_alignment;
  int idx = -1;
  unsigned i;
  uint8_t *ctx_ptr;

  for (i = 0; i < sizeof(builtin_ciphers) / sizeof(builtin_ciphers[0]);
       i++) {
    if (algo == builtin_ciphers[i].algo) {
      idx = i;
      break;
    }
  }

  if (idx == -1)
    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

  ctx = gnutls_calloc(1,
          sizeof(*ctx) + builtin_ciphers[idx].ctx_size + 16);
  if (ctx == NULL) {
    gnutls_assert();
    return GNUTLS_E_MEMORY_ERROR;
  }

  ctx->enc = enc;
  ctx_ptr = ((uint8_t *)ctx) + sizeof(*ctx);

  cur_alignment = ((uintptr_t)ctx_ptr) % 16;
  if (cur_alignment > 0)
    ctx_ptr += 16 - cur_alignment;

  ctx->ctx_ptr = ctx_ptr;
  ctx->cipher = &builtin_ciphers[idx];

  *_ctx = ctx;

  return 0;
}

static int wrap_nettle_cipher_setkey(void *_ctx, const void *key,
             size_t keysize)
{
  struct nettle_cipher_ctx *ctx = _ctx;

  if (ctx->cipher->key_size > 0 &&
      unlikely(keysize != ctx->cipher->key_size)) {
    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
  } else if (ctx->cipher->key_size == 0) {
    ctx->cipher->gen_set_key(ctx->ctx_ptr, keysize, key);
    return 0;
  }

  switch (ctx->cipher->algo) {
  case GNUTLS_CIPHER_AES_128_XTS:
    if (_gnutls_fips_mode_enabled() &&
        gnutls_memcmp(key, (char *)key + AES128_KEY_SIZE,
          AES128_KEY_SIZE) == 0)
      return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
    break;
  case GNUTLS_CIPHER_AES_256_XTS:
    if (_gnutls_fips_mode_enabled() &&
        gnutls_memcmp(key, (char *)key + AES256_KEY_SIZE,
          AES256_KEY_SIZE) == 0)
      return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
    break;
  default:
    break;
  }

  if (ctx->enc)
    ctx->cipher->set_encrypt_key(ctx->ctx_ptr, key);
  else
    ctx->cipher->set_decrypt_key(ctx->ctx_ptr, key);

  switch (ctx->cipher->algo) {
  case GNUTLS_CIPHER_AES_128_GCM:
  case GNUTLS_CIPHER_AES_192_GCM:
  case GNUTLS_CIPHER_AES_256_GCM:
    ctx->rekey_counter = 0;
    break;
  default:
    break;
  }

  return 0;
}

static int wrap_nettle_cipher_setiv(void *_ctx, const void *iv, size_t iv_size)
{
  struct nettle_cipher_ctx *ctx = _ctx;
  unsigned max_iv;

  switch (ctx->cipher->algo) {
  case GNUTLS_CIPHER_AES_128_GCM:
  case GNUTLS_CIPHER_AES_192_GCM:
  case GNUTLS_CIPHER_AES_256_GCM:
    FIPS_RULE(iv_size < GCM_IV_SIZE, GNUTLS_E_INVALID_REQUEST,
        "access to short GCM nonce size\n");
    ctx->rekey_counter = 0;
    break;
  case GNUTLS_CIPHER_SALSA20_256:
  case GNUTLS_CIPHER_ESTREAM_SALSA20_256:
    if (iv_size != SALSA20_IV_SIZE)
      return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
    break;
  default:
    break;
  }

  max_iv = ctx->cipher->max_iv_size;
  if (max_iv == 0)
    max_iv = MAX_CIPHER_BLOCK_SIZE;

  if (iv_size > max_iv)
    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

  if (ctx->cipher->set_iv) {
    ctx->cipher->set_iv(ctx->ctx_ptr, iv_size, iv);
  } else {
    if (iv)
      memcpy(ctx->iv, iv, iv_size);
    ctx->iv_size = iv_size;
  }

  return 0;
}

static int wrap_nettle_cipher_getiv(void *_ctx, void *iv, size_t iv_size)
{
  struct nettle_cipher_ctx *ctx = _ctx;

  if (iv_size < ctx->iv_size)
    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

  memcpy(iv, ctx->iv, ctx->iv_size);

  return (int)ctx->iv_size;
}

static int wrap_nettle_cipher_decrypt(void *_ctx, const void *encr,
              size_t encr_size, void *plain,
              size_t plain_size)
{
  struct nettle_cipher_ctx *ctx = _ctx;

  if (unlikely(ctx->cipher->decrypt == NULL))
    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

  ctx->cipher->decrypt(ctx, encr_size, plain, encr);

  return 0;
}

static int wrap_nettle_cipher_encrypt(void *_ctx, const void *plain,
              size_t plain_size, void *encr,
              size_t encr_size)
{
  struct nettle_cipher_ctx *ctx = _ctx;
  int ret;

  if (unlikely(ctx->cipher->encrypt == NULL))
    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

  switch (ctx->cipher->algo) {
  case GNUTLS_CIPHER_AES_128_GCM:
  case GNUTLS_CIPHER_AES_192_GCM:
  case GNUTLS_CIPHER_AES_256_GCM:
    ret = record_aes_gcm_encrypt_size(&ctx->rekey_counter,
              plain_size);
    if (ret < 0) {
      return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
    }
    break;
  default:
    break;
  }

  ctx->cipher->encrypt(ctx, plain_size, encr, plain);

  return 0;
}

static int wrap_nettle_cipher_aead_encrypt(void *_ctx, const void *nonce,
             size_t nonce_size, const void *auth,
             size_t auth_size, size_t tag_size,
             const void *plain, size_t plain_size,
             void *encr, size_t encr_size)
{
  struct nettle_cipher_ctx *ctx = _ctx;

  if (ctx->cipher->aead_encrypt == NULL) {
    /* proper AEAD cipher */
    unsigned max_iv;

    if (encr_size < plain_size + tag_size)
      return gnutls_assert_val(GNUTLS_E_SHORT_MEMORY_BUFFER);

    max_iv = ctx->cipher->max_iv_size;
    if (max_iv == 0)
      max_iv = MAX_CIPHER_BLOCK_SIZE;

    if (nonce_size > max_iv)
      return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

    ctx->cipher->set_iv(ctx->ctx_ptr, nonce_size, nonce);
    ctx->cipher->auth(ctx->ctx_ptr, auth_size, auth);

    ctx->cipher->encrypt(ctx, plain_size, encr, plain);

    ctx->cipher->tag(ctx->ctx_ptr, tag_size,
         ((uint8_t *)encr) + plain_size);
  } else {
    /* CCM-style cipher */

    switch (ctx->cipher->algo) {
    case GNUTLS_CIPHER_AES_128_CCM:
    case GNUTLS_CIPHER_AES_256_CCM:
      /* SP800-38C A.1 says Tlen must be a multiple of 16
       * between 32 and 128.
       */
      switch (tag_size) {
      case 4:
      case 6:
        /* SP800-38C B.2 says Tlen smaller than 64
         * should not be used under sufficient
         * restriction. We simply allow those for now.
         */
        FALLTHROUGH;
      case 8:
      case 10:
      case 12:
      case 14:
      case 16:
        break;
      default:
        if (_gnutls_fips_mode_enabled()) {
          _gnutls_switch_fips_state(
            GNUTLS_FIPS140_OP_ERROR);
          return gnutls_assert_val(
            GNUTLS_E_INVALID_REQUEST);
        }
        break;
      }
      break;
    default:
      break;
    }

    ctx->cipher->aead_encrypt(ctx, nonce_size, nonce, auth_size,
            auth, tag_size, tag_size + plain_size,
            encr, plain);
  }
  return 0;
}

static int wrap_nettle_cipher_aead_decrypt(void *_ctx, const void *nonce,
             size_t nonce_size, const void *auth,
             size_t auth_size, size_t tag_size,
             const void *encr, size_t encr_size,
             void *plain, size_t plain_size)
{
  struct nettle_cipher_ctx *ctx = _ctx;
  int ret;

  if (unlikely(encr_size < tag_size))
    return gnutls_assert_val(GNUTLS_E_DECRYPTION_FAILED);

  if (ctx->cipher->aead_decrypt == NULL) {
    /* proper AEAD cipher */
    uint8_t tag[MAX_HASH_SIZE];
    unsigned max_iv;

    max_iv = ctx->cipher->max_iv_size;
    if (max_iv == 0)
      max_iv = MAX_CIPHER_BLOCK_SIZE;

    if (nonce_size > max_iv)
      return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);

    ctx->cipher->set_iv(ctx->ctx_ptr, nonce_size, nonce);
    ctx->cipher->auth(ctx->ctx_ptr, auth_size, auth);

    encr_size -= tag_size;

    if (unlikely(plain_size < encr_size))
      return gnutls_assert_val(GNUTLS_E_SHORT_MEMORY_BUFFER);

    ctx->cipher->decrypt(ctx, encr_size, plain, encr);

    ctx->cipher->tag(ctx->ctx_ptr, tag_size, tag);

    if (gnutls_memcmp(((uint8_t *)encr) + encr_size, tag,
          tag_size) != 0)
      return gnutls_assert_val(GNUTLS_E_DECRYPTION_FAILED);
  } else {
    /* CCM-style cipher */
    encr_size -= tag_size;

    if (unlikely(plain_size < encr_size))
      return gnutls_assert_val(GNUTLS_E_SHORT_MEMORY_BUFFER);

    switch (ctx->cipher->algo) {
    case GNUTLS_CIPHER_AES_128_CCM:
    case GNUTLS_CIPHER_AES_256_CCM:
      /* SP800-38C A.1 says Tlen must be a multiple of 16
       * between 32 and 128.
       */
      switch (tag_size) {
      case 4:
      case 6:
        /* SP800-38C B.2 says Tlen smaller than 64
         * should not be used under sufficient
         * restriction. We simply allow those for now.
         */
        FALLTHROUGH;
      case 8:
      case 10:
      case 12:
      case 14:
      case 16:
        break;
      default:
        if (_gnutls_fips_mode_enabled()) {
          _gnutls_switch_fips_state(
            GNUTLS_FIPS140_OP_ERROR);
          return gnutls_assert_val(
            GNUTLS_E_INVALID_REQUEST);
        }
        break;
      }
      break;
    default:
      break;
    }

    ret = ctx->cipher->aead_decrypt(ctx, nonce_size, nonce,
            auth_size, auth, tag_size,
            encr_size, plain, encr);
    if (unlikely(ret == 0))
      return gnutls_assert_val(GNUTLS_E_DECRYPTION_FAILED);
  }
  return 0;
}

static int wrap_nettle_cipher_auth(void *_ctx, const void *plain,
           size_t plain_size)
{
  struct nettle_cipher_ctx *ctx = _ctx;

  ctx->cipher->auth(ctx->ctx_ptr, plain_size, plain);

  return 0;
}

static void wrap_nettle_cipher_tag(void *_ctx, void *tag, size_t tag_size)
{
  struct nettle_cipher_ctx *ctx = _ctx;

  ctx->cipher->tag(ctx->ctx_ptr, tag_size, tag);
}

static void wrap_nettle_cipher_close(void *_ctx)
{
  struct nettle_cipher_ctx *ctx = _ctx;

  zeroize_temp_key(ctx->ctx_ptr, ctx->cipher->ctx_size);
  gnutls_free(ctx);
}

gnutls_crypto_cipher_st _gnutls_cipher_ops = {
  .init = wrap_nettle_cipher_init,
  .exists = wrap_nettle_cipher_exists,
  .setiv = wrap_nettle_cipher_setiv,
  .getiv = wrap_nettle_cipher_getiv,
  .setkey = wrap_nettle_cipher_setkey,
  .encrypt = wrap_nettle_cipher_encrypt,
  .decrypt = wrap_nettle_cipher_decrypt,
  .aead_encrypt = wrap_nettle_cipher_aead_encrypt,
  .aead_decrypt = wrap_nettle_cipher_aead_decrypt,
  .deinit = wrap_nettle_cipher_close,
  .auth = wrap_nettle_cipher_auth,
  .tag = wrap_nettle_cipher_tag,
};

Coverage Report

Created: 2024-06-20 06:28