unetd/curve25519.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2018-2020 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
 */

#include "curve25519.h"

#include <stdint.h>
#include <string.h>
#include "utils.h"

#ifndef __BYTE_ORDER__
#include <sys/param.h>
#if !defined(BYTE_ORDER) || !defined(BIG_ENDIAN) || !defined(LITTLE_ENDIAN)
#error "Unable to determine endianness."
#endif
#define __BYTE_ORDER__ BYTE_ORDER
#define __ORDER_BIG_ENDIAN__ BIG_ENDIAN
#define __ORDER_LITTLE_ENDIAN__ LITTLE_ENDIAN
#endif

#ifdef __linux__
#include <linux/types.h>
typedef __u64 u64;
typedef __u32 u32;
typedef __u8 u8;
typedef __s64 s64;
#else
typedef uint64_t u64, __le64;
typedef uint32_t u32, __le32;
typedef uint8_t u8;
typedef int64_t s64;
#endif
#ifndef __unused
#define __unused  __attribute__((unused))
#endif
#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 __always_inline __unused void put_unaligned_le64(u64 s, u8 *d)
{
	__le64 l = cpu_to_le64(s);
	__builtin_memcpy(d, &l, sizeof(l));
}

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

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

void curve25519_generate_public(uint8_t pub[static CURVE25519_KEY_SIZE], const uint8_t secret[static CURVE25519_KEY_SIZE])
{
	static const uint8_t basepoint[CURVE25519_KEY_SIZE] __aligned(sizeof(uintptr_t)) = { 9 };

	curve25519(pub, secret, basepoint);
}

void curve25519(uint8_t mypublic[static CURVE25519_KEY_SIZE], const uint8_t secret[static CURVE25519_KEY_SIZE], const uint8_t basepoint[static CURVE25519_KEY_SIZE])
{
	curve25519_generic(mypublic, secret, basepoint);
}