/* $OpenBSD: getentropy_win.c,v 1.4 2015/09/11 11:52:55 deraadt Exp $ */ /* * Copyright (c) 2014, Theo de Raadt <deraadt@openbsd.org> * Copyright (c) 2014, Bob Beck <beck@obtuse.com> * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. * * Emulation of getentropy(2) as documented at: * http://www.openbsd.org/cgi-bin/man.cgi/OpenBSD-current/man2/getentropy.2 */ #include <windows.h> #include <errno.h> #include <stdint.h> #include <sys/types.h> #include <wincrypt.h> #include <process.h> int getentropy(void *buf, size_t len); /* * On Windows, CryptGenRandom is supposed to be a well-seeded * cryptographically strong random number generator. */ int getentropy(void *buf, size_t len) { HCRYPTPROV provider; if (len > 256) { errno = EIO; return (-1); } if (CryptAcquireContext(&provider, NULL, NULL, PROV_RSA_FULL, CRYPT_VERIFYCONTEXT) == 0) goto fail; if (CryptGenRandom(provider, len, buf) == 0) { CryptReleaseContext(provider, 0); goto fail; } CryptReleaseContext(provider, 0); return (0); fail: errno = EIO; return (-1); }