/*
 * 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,
};