wireguard-tools/src/curve25519.c

/* SPDX-License-Identifier: GPL-2.0
 *
 * Copyright (C) 2016-2017 INRIA and Microsoft Corporation.
 * Copyright (C) 2015-2016 The fiat-crypto Authors.
 * Copyright (C) 2018 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
 *
 * This is a machine-generated formally verified implementation of curve25519 DH from:
 * https://github.com/mitls/hacl-star and https://github.com/mit-plv/fiat-crypto
 */

#include "curve25519.h"

#include <stdint.h>
#include <string.h>
#include <endian.h>

typedef uint64_t u64;
typedef uint32_t u32;
typedef uint8_t u8;
typedef int64_t s64;
typedef u64 __le64;
typedef u32 __le32;
#define le64_to_cpup(a) le64toh(*(a));
#define le32_to_cpup(a) le32toh(*(a));
#define cpu_to_le64(a) htole64(a);
#ifndef __always_inline
#define __always_inline __inline __attribute__((__always_inline__))
#endif
#ifndef noinline
#define noinline __attribute__((noinline))
#endif
#ifndef __aligned
#define __aligned(x) __attribute__((aligned(x)))
#endif
#ifndef __force
#define __force
#endif

static noinline void memzero_explicit(void *s, size_t count)
{
	memset(s, 0, count);
	__asm__ __volatile__("": :"r"(s) :"memory");
}

static __always_inline void normalize_secret(u8 secret[CURVE25519_POINT_SIZE])
{
	secret[0] &= 248;
	secret[31] &= 127;
	secret[31] |= 64;
}

#ifdef __SIZEOF_INT128__
#include "../crypto/curve25519-hacl64.h"
#else
#include "../crypto/curve25519-fiat32.h"
#endif

void curve25519_generate_public(uint8_t pub[static CURVE25519_POINT_SIZE], const uint8_t secret[static CURVE25519_POINT_SIZE])
{
	static const uint8_t basepoint[CURVE25519_POINT_SIZE] = { 9 };

	curve25519(pub, secret, basepoint);
}

void curve25519(uint8_t mypublic[static CURVE25519_POINT_SIZE], const uint8_t secret[static CURVE25519_POINT_SIZE], const uint8_t basepoint[static CURVE25519_POINT_SIZE])
{
	curve25519_generic(mypublic, secret, basepoint);
}