WireGuard/src/tools/genkey.c

60 lines
1.4 KiB
C

/* Copyright 2015-2016 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved. */
#include <errno.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <syscall.h>
#include <unistd.h>
#include <string.h>
#include "curve25519.h"
#include "base64.h"
#ifdef __NR_getrandom
static inline ssize_t get_random_bytes(uint8_t *out, size_t len)
{
return syscall(__NR_getrandom, out, len, 0);
}
#else
#include <fcntl.h>
static inline ssize_t get_random_bytes(uint8_t *out, size_t len)
{
ssize_t ret;
int fd = open("/dev/urandom", O_RDONLY);
if (fd < 0)
return fd;
ret = read(fd, out, len);
close(fd);
return ret;
}
#endif
int genkey_main(int argc, char *argv[])
{
unsigned char private_key[CURVE25519_POINT_SIZE];
char private_key_base64[b64_len(CURVE25519_POINT_SIZE)];
struct stat stat;
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(private_key, CURVE25519_POINT_SIZE) != CURVE25519_POINT_SIZE) {
perror("getrandom");
return 1;
}
if (argc && !strcmp(argv[0], "genkey"))
curve25519_normalize_secret(private_key);
if (b64_ntop(private_key, sizeof(private_key), private_key_base64, sizeof(private_key_base64)) < 0) {
errno = EINVAL;
perror("b64");
return 1;
}
puts(private_key_base64);
return 0;
}