From: Wouter Wijngaards <wouter@nlnetlabs.nl>
Date: Sat, 12 Jul 2014 20:19:14 +0000 (+0000)
Subject: getentropy from Theo de Raadt
X-Git-Tag: release-1.5.0rc1~71
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=10e378f13bfc1ab2e61fdab0a91e64ddf8524265;p=thirdparty%2Funbound.git

getentropy from Theo de Raadt


git-svn-id: file:///svn/unbound/trunk@3189 be551aaa-1e26-0410-a405-d3ace91eadb9
---

diff --git a/compat/getentropy_win.c b/compat/getentropy_win.c
index cad15d4aa..00cce559a 100644
--- a/compat/getentropy_win.c
+++ b/compat/getentropy_win.c
@@ -1,65 +1,55 @@
-/* getentropy_win.c - get entropy on Windows.
-*
- * Copyright (c) 2014, NLnet Labs. All rights reserved.
+/*	$OpenBSD$	*/
+
+/*
+ * 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.
  *
- * This software is open source.
- * 
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 
- * Redistributions of source code must retain the above copyright notice,
- * this list of conditions and the following disclaimer.
- * 
- * Redistributions in binary form must reproduce the above copyright notice,
- * this list of conditions and the following disclaimer in the documentation
- * and/or other materials provided with the distribution.
- * 
- * Neither the name of the NLNET LABS nor the names of its contributors may
- * be used to endorse or promote products derived from this software without
- * specific prior written permission.
- * 
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
- * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
- * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
- * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
- * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
- * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ * 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.
  */
 #include "config.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)
 {
-	HMODULE lib;
+	HCRYPTPROV provider;
 
-	if(len > 256) {
+	if (len > 256) {
 		errno = EIO;
 		return -1;
 	}
 
-	/* Get entropy with windows secure random number generator,
-	 * for windows XP and later, it is in the ADVAPI32 dll */
-	lib = LoadLibrary("ADVAPI32.DLL");
-	if(lib) {
-		/* Load the RtlGenRandom function */
-		BOOLEAN (APIENTRY* genrandom)(void*,ULONG) =
-			(BOOLEAN (APIENTRY*)(void*,ULONG))
-			GetProcAddress(lib, "SystemFunction036");
-		if(genrandom) {
-			if(genrandom(buf, len)) {
-				FreeLibrary(lib);
-				return 0; /* success */
-			}
-		}
-		FreeLibrary(lib);
+	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;
+	return (-1);
 }