1*adf37648SKyle Evans // SPDX-License-Identifier: GPL-2.0 OR MIT
2*adf37648SKyle Evans /*
3*adf37648SKyle Evans * Copyright (C) 2015-2020 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
4*adf37648SKyle Evans */
5*adf37648SKyle Evans
6*adf37648SKyle Evans #include <errno.h>
7*adf37648SKyle Evans #include <stdio.h>
8*adf37648SKyle Evans #include <stdbool.h>
9*adf37648SKyle Evans #include <unistd.h>
10*adf37648SKyle Evans #include <sys/types.h>
11*adf37648SKyle Evans #include <sys/stat.h>
12*adf37648SKyle Evans #include <string.h>
13*adf37648SKyle Evans #include <fcntl.h>
14*adf37648SKyle Evans #ifdef __linux__
15*adf37648SKyle Evans #include <sys/syscall.h>
16*adf37648SKyle Evans #endif
17*adf37648SKyle Evans #ifdef __APPLE__
18*adf37648SKyle Evans #include <AvailabilityMacros.h>
19*adf37648SKyle Evans #ifndef MAC_OS_X_VERSION_10_12
20*adf37648SKyle Evans #define MAC_OS_X_VERSION_10_12 101200
21*adf37648SKyle Evans #endif
22*adf37648SKyle Evans #if MAC_OS_X_VERSION_MIN_REQUIRED >= MAC_OS_X_VERSION_10_12
23*adf37648SKyle Evans #include <sys/random.h>
24*adf37648SKyle Evans #endif
25*adf37648SKyle Evans #endif
26*adf37648SKyle Evans
27*adf37648SKyle Evans #include "curve25519.h"
28*adf37648SKyle Evans #include "encoding.h"
29*adf37648SKyle Evans #include "subcommands.h"
30*adf37648SKyle Evans
31*adf37648SKyle Evans #ifndef _WIN32
get_random_bytes(uint8_t * out,size_t len)32*adf37648SKyle Evans static inline bool __attribute__((__warn_unused_result__)) get_random_bytes(uint8_t *out, size_t len)
33*adf37648SKyle Evans {
34*adf37648SKyle Evans ssize_t ret = 0;
35*adf37648SKyle Evans size_t i;
36*adf37648SKyle Evans int fd;
37*adf37648SKyle Evans
38*adf37648SKyle Evans if (len > 256) {
39*adf37648SKyle Evans errno = EOVERFLOW;
40*adf37648SKyle Evans return false;
41*adf37648SKyle Evans }
42*adf37648SKyle Evans
43*adf37648SKyle Evans #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)))
44*adf37648SKyle Evans if (!getentropy(out, len))
45*adf37648SKyle Evans return true;
46*adf37648SKyle Evans #endif
47*adf37648SKyle Evans
48*adf37648SKyle Evans #if defined(__NR_getrandom) && defined(__linux__)
49*adf37648SKyle Evans if (syscall(__NR_getrandom, out, len, 0) == (ssize_t)len)
50*adf37648SKyle Evans return true;
51*adf37648SKyle Evans #endif
52*adf37648SKyle Evans
53*adf37648SKyle Evans fd = open("/dev/urandom", O_RDONLY);
54*adf37648SKyle Evans if (fd < 0)
55*adf37648SKyle Evans return false;
56*adf37648SKyle Evans for (errno = 0, i = 0; i < len; i += ret, ret = 0) {
57*adf37648SKyle Evans ret = read(fd, out + i, len - i);
58*adf37648SKyle Evans if (ret <= 0) {
59*adf37648SKyle Evans ret = errno ? -errno : -EIO;
60*adf37648SKyle Evans break;
61*adf37648SKyle Evans }
62*adf37648SKyle Evans }
63*adf37648SKyle Evans close(fd);
64*adf37648SKyle Evans errno = -ret;
65*adf37648SKyle Evans return i == len;
66*adf37648SKyle Evans }
67*adf37648SKyle Evans #else
68*adf37648SKyle Evans #include <ntsecapi.h>
get_random_bytes(uint8_t * out,size_t len)69*adf37648SKyle Evans static inline bool __attribute__((__warn_unused_result__)) get_random_bytes(uint8_t *out, size_t len)
70*adf37648SKyle Evans {
71*adf37648SKyle Evans return RtlGenRandom(out, len);
72*adf37648SKyle Evans }
73*adf37648SKyle Evans #endif
74*adf37648SKyle Evans
genkey_main(int argc,const char * argv[])75*adf37648SKyle Evans int genkey_main(int argc, const char *argv[])
76*adf37648SKyle Evans {
77*adf37648SKyle Evans uint8_t key[WG_KEY_LEN];
78*adf37648SKyle Evans char base64[WG_KEY_LEN_BASE64];
79*adf37648SKyle Evans struct stat stat;
80*adf37648SKyle Evans
81*adf37648SKyle Evans if (argc != 1) {
82*adf37648SKyle Evans fprintf(stderr, "Usage: %s %s\n", PROG_NAME, argv[0]);
83*adf37648SKyle Evans return 1;
84*adf37648SKyle Evans }
85*adf37648SKyle Evans
86*adf37648SKyle Evans if (!fstat(STDOUT_FILENO, &stat) && S_ISREG(stat.st_mode) && stat.st_mode & S_IRWXO)
87*adf37648SKyle Evans fputs("Warning: writing to world accessible file.\nConsider setting the umask to 077 and trying again.\n", stderr);
88*adf37648SKyle Evans
89*adf37648SKyle Evans if (!get_random_bytes(key, WG_KEY_LEN)) {
90*adf37648SKyle Evans perror("getrandom");
91*adf37648SKyle Evans return 1;
92*adf37648SKyle Evans }
93*adf37648SKyle Evans if (!strcmp(argv[0], "genkey"))
94*adf37648SKyle Evans curve25519_clamp_secret(key);
95*adf37648SKyle Evans
96*adf37648SKyle Evans key_to_base64(base64, key);
97*adf37648SKyle Evans puts(base64);
98*adf37648SKyle Evans return 0;
99*adf37648SKyle Evans }
100