1 /*
2 crypto.c -- Cryptographic miscellaneous functions and initialisation
3 Copyright (C) 2007-2021 Guus Sliepen <guus@tinc-vpn.org>
4
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
9
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
14
15 You should have received a copy of the GNU General Public License along
16 with this program; if not, write to the Free Software Foundation, Inc.,
17 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
18 */
19
20 #include "../system.h"
21
22 #include "../crypto.h"
23
24 #ifndef HAVE_MINGW
25
26 static int random_fd = -1;
27
random_init(void)28 static void random_init(void) {
29 random_fd = open("/dev/urandom", O_RDONLY);
30
31 if(random_fd < 0) {
32 random_fd = open("/dev/random", O_RDONLY);
33 }
34
35 if(random_fd < 0) {
36 fprintf(stderr, "Could not open source of random numbers: %s\n", strerror(errno));
37 abort();
38 }
39 }
40
random_exit(void)41 static void random_exit(void) {
42 close(random_fd);
43 }
44
randomize(void * vout,size_t outlen)45 void randomize(void *vout, size_t outlen) {
46 char *out = vout;
47
48 while(outlen) {
49 ssize_t len = read(random_fd, out, outlen);
50
51 if(len <= 0) {
52 if(len == -1 && (errno == EAGAIN || errno == EINTR)) {
53 continue;
54 }
55
56 fprintf(stderr, "Could not read random numbers: %s\n", strerror(errno));
57 abort();
58 }
59
60 out += len;
61 outlen -= len;
62 }
63 }
64
65 #else
66
67 #include <wincrypt.h>
68 HCRYPTPROV prov;
69
random_init(void)70 void random_init(void) {
71 if(!CryptAcquireContext(&prov, NULL, NULL, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT)) {
72 fprintf(stderr, "CryptAcquireContext() failed!\n");
73 abort();
74 }
75 }
76
random_exit(void)77 void random_exit(void) {
78 CryptReleaseContext(prov, 0);
79 }
80
randomize(void * out,size_t outlen)81 void randomize(void *out, size_t outlen) {
82 if(!CryptGenRandom(prov, outlen, out)) {
83 fprintf(stderr, "CryptGenRandom() failed\n");
84 abort();
85 }
86 }
87
88 #endif
89
crypto_init(void)90 void crypto_init(void) {
91 random_init();
92 }
93
crypto_exit(void)94 void crypto_exit(void) {
95 random_exit();
96 }
97