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wireguard-tools/src/genkey.c

96 lines
2.1 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*/
#include <errno.h>
#include <stdio.h>
#include <stdbool.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <string.h>
#include <fcntl.h>
#ifdef __linux__
#include <sys/syscall.h>
#endif
#ifdef __APPLE__
#include <AvailabilityMacros.h>
#ifndef MAC_OS_X_VERSION_10_12
#define MAC_OS_X_VERSION_10_12 101200
#endif
#if MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_12
#include <sys/random.h>
#endif
#endif
#include "curve25519.h"
#include "encoding.h"
#include "subcommands.h"
#ifndef WINCOMPAT
static inline bool __attribute__((__warn_unused_result__)) get_random_bytes(uint8_t *out, size_t len)
{
ssize_t ret = 0;
size_t i;
int fd;
if (len > 256) {
errno = EOVERFLOW;
return false;
}
#if defined(__OpenBSD__) || (defined(__APPLE__) && MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_12) || (defined(__GLIBC__) && (__GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 25)))
if (!getentropy(out, len))
return true;
#endif
#if defined(__NR_getrandom) && defined(__linux__)
if (syscall(__NR_getrandom, out, len, 0) == (ssize_t)len)
return true;
#endif
fd = open("/dev/urandom", O_RDONLY);
if (fd < 0)
return false;
for (errno = 0, i = 0; i < len; i += ret, ret = 0) {
ret = read(fd, out + i, len - i);
if (ret <= 0) {
ret = errno ? -errno : -EIO;
break;
}
}
close(fd);
errno = -ret;
return i == len;
}
#else
#include "wincompat/getrandom.c"
#endif
int genkey_main(int argc, char *argv[])
{
uint8_t key[WG_KEY_LEN];
char base64[WG_KEY_LEN_BASE64];
struct stat stat;
if (argc != 1) {
fprintf(stderr, "Usage: %s %s\n", PROG_NAME, argv[0]);
return 1;
}
if (!fstat(STDOUT_FILENO, &stat) && S_ISREG(stat.st_mode) && stat.st_mode & S_IRWXO)
fputs("Warning: writing to world accessible file.\nConsider setting the umask to 077 and trying again.\n", stderr);
if (!get_random_bytes(key, WG_KEY_LEN)) {
perror("getrandom");
return 1;
}
if (!strcmp(argv[0], "genkey"))
curve25519_clamp_secret(key);
key_to_base64(base64, key);
puts(base64);
return 0;
}