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