/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>
#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
_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,
   },
};

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

    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];

    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: 2023-03-26 07:33