fixes #1083 Random number improvements

1 files changed, 15 insertions, 13 deletions

diff --git a/src/platform/windows/win_rand.c b/src/platform/windows/win_rand.c
index afe703ef..21568a81 100644
--- a/src/platform/windows/win_rand.c
+++ b/src/platform/windows/win_rand.c
@@ -1,5 +1,5 @@
 //
-// Copyright 2017 Garrett D'Amore <garrett@damore.org>
+// Copyright 2020 Staysail Systems, Inc. <info@staysail.tech>
 //
 // This software is supplied under the terms of the MIT License, a
 // copy of which should be located in the distribution where this
@@ -11,22 +11,24 @@
 
 #ifdef NNG_PLATFORM_WINDOWS
 
+#ifndef _CRT_RAND_S
+#define _CRT_RAND_S
+#endif
+
 #include <stdlib.h>
 
-void
-nni_plat_seed_prng(void *buf, size_t bufsz)
+uint32_t
+nni_random(void)
 {
 	unsigned val;
 
-	// The rand_s routine uses RtlGenRandom to get high quality
-	// pseudo random numbers (i.e. numbers that should be good enough
-	// for use with crypto keying.)
-	while (bufsz > sizeof(val)) {
-		rand_s(&val);
-		memcpy(buf, &val, sizeof(val));
-		buf = (((char *) buf) + sizeof(val));
-		bufsz -= sizeof(val);
-	}
+	// rand_s is claimed by Microsoft to generate cryptographically
+	// secure numbers.  It also is claimed that this will only fail
+	// for EINVAL if val is NULL (not the case here).  Other error
+	// conditions might be possible, but we have no way to tell.
+	// For now we just ignore that possibility.
+	rand_s(&val);
+	return ((uint32_t)val);
 }
 
-#endif // NNG_PLATFORM_WINDOWS
+#endif // NNG_PLATFORM_WINDOWS
\ No newline at end of file