util: add secure pseudorandom number generator

2013-04-11 12:31:58 +02:00
parent 69042ecd1b
commit 87d1bdb87c
2 changed files with 92 additions and 0 deletions
@@ -15,9 +15,11 @@

 #define MAX_FAST_RANDOM_VALUE		0x7fff
 #define MAX_RANDOM_VALUE			0x7fffffffu
+#define MAX_SECURE_RANDOM_VALUE		0xffffffffu

 static const int	kFastRandomShift		= 15;
 static const int	kRandomShift			= 31;
+static const int	kSecureRandomShift		= 32;

 #ifdef __cplusplus
 extern "C" {
@@ -25,6 +27,7 @@ extern "C" {

 unsigned int	fast_random_value(void);
 unsigned int	random_value(void);
+unsigned int	secure_random_value(void);

 #ifdef __cplusplus
 }
@@ -63,6 +66,21 @@ get_random()
 }


+template<typename T>
+T
+secure_get_random()
+{
+	size_t shift = 0;
+	T random = 0;
+	while (shift < sizeof(T) * 8) {
+		random |= (T)secure_random_value() << shift;
+		shift += kSecureRandomShift;
+	}
+
+	return random;
+}
+
+
 #endif	// __cplusplus

 #endif	// KERNEL_UTIL_RANDOM_H