1 /* $OpenBSD$ */ 2 3 /* 4 * Copyright (c) 2014, Theo de Raadt <deraadt@openbsd.org> 5 * Copyright (c) 2014, Bob Beck <beck@obtuse.com> 6 * 7 * Permission to use, copy, modify, and distribute this software for any 8 * purpose with or without fee is hereby granted, provided that the above 9 * copyright notice and this permission notice appear in all copies. 10 * 11 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 17 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 18 */ 19 20 #include <windows.h> 21 #include <errno.h> 22 #include <stdint.h> 23 #include <sys/types.h> 24 #include <wincrypt.h> 25 #include <process.h> 26 27 int getentropy(void *buf, size_t len); 28 29 /* 30 * On Windows, CryptGenRandom is supposed to be a well-seeded 31 * cryptographically strong random number generator. 32 */ 33 int 34 getentropy(void *buf, size_t len) 35 { 36 HCRYPTPROV provider; 37 38 if (len > 256) { 39 errno = EIO; 40 return -1; 41 } 42 43 if (CryptAcquireContext(&provider, NULL, NULL, PROV_RSA_FULL, 44 CRYPT_VERIFYCONTEXT) == 0) 45 goto fail; 46 if (CryptGenRandom(provider, len, buf) == 0) { 47 CryptReleaseContext(provider, 0); 48 goto fail; 49 } 50 CryptReleaseContext(provider, 0); 51 return (0); 52 53 fail: 54 errno = EIO; 55 return (-1); 56 } 57