feat: upgrade session keys to use mersenne twister (#1155)

* upgrade session keys to use mersenne twister

* arithmetic type static assert and windows min/max macro undef

dAuthServer/AuthServer.cpp

@@ -29,6 +29,7 @@ namespace Game {
 	dServer* server = nullptr;
 	dConfig* config = nullptr;
 	bool shouldShutdown = false;
+	std::mt19937 randomEngine;
 }
 
 dLogger* SetupLogger();
@@ -83,6 +84,8 @@ int main(int argc, char** argv) {
 	delete res;
 	delete stmt;
 
+	Game::randomEngine = std::mt19937(time(0));
+
 	//It's safe to pass 'localhost' here, as the IP is only used as the external IP.
 	uint32_t maxClients = 50;
 	uint32_t ourPort = 1001; //LU client is hardcoded to use this for auth port, so I'm making it the default.

dCommon/GeneralUtils.h

@@ -111,29 +111,6 @@ namespace GeneralUtils {
 	 */
 	bool CheckBit(int64_t value, uint32_t index);
 
-	// MARK: Random Number Generation
-
-	//! Generates a random number
-	/*!
-	  \param min The minimum the generate from
-	  \param max The maximum to generate to
-	 */
-	template <typename T>
-	inline T GenerateRandomNumber(std::size_t min, std::size_t max) {
-		// Make sure it is a numeric type
-		static_assert(std::is_arithmetic<T>::value, "Not an arithmetic type");
-
-		if constexpr (std::is_integral_v<T>) {  // constexpr only necessary on first statement
-			std::uniform_int_distribution<T> distribution(min, max);
-			return distribution(Game::randomEngine);
-		} else if (std::is_floating_point_v<T>) {
-			std::uniform_real_distribution<T> distribution(min, max);
-			return distribution(Game::randomEngine);
-		}
-
-		return T();
-	}
-
 	bool ReplaceInString(std::string& str, const std::string& from, const std::string& to);
 
 	std::u16string ReadWString(RakNet::BitStream* inStream);
@@ -223,4 +200,42 @@ namespace GeneralUtils {
 		std::hash<T> h;
 		s ^= h(v) + 0x9e3779b9 + (s << 6) + (s >> 2);
 	}
+
+	// MARK: Random Number Generation
+
+	//! Generates a random number
+	/*!
+	  \param min The minimum the generate from
+	  \param max The maximum to generate to
+	 */
+	template <typename T>
+	inline T GenerateRandomNumber(std::size_t min, std::size_t max) {
+		// Make sure it is a numeric type
+		static_assert(std::is_arithmetic<T>::value, "Not an arithmetic type");
+
+		if constexpr (std::is_integral_v<T>) {  // constexpr only necessary on first statement
+			std::uniform_int_distribution<T> distribution(min, max);
+			return distribution(Game::randomEngine);
+		} else if (std::is_floating_point_v<T>) {
+			std::uniform_real_distribution<T> distribution(min, max);
+			return distribution(Game::randomEngine);
+		}
+
+		return T();
+	}
+
+// on Windows we need to undef these or else they conflict with our numeric limits calls
+// DEVELOPERS DEVELOPERS DEVELOPERS DEVELOPERS DEVELOPERS DEVELOPERS DEVELOPERS DEVELOPERS
+#ifdef _WIN32
+#undef min
+#undef max
+#endif
+
+	template <typename T>
+	inline T GenerateRandomNumber() {
+		// Make sure it is a numeric type
+		static_assert(std::is_arithmetic<T>::value, "Not an arithmetic type");
+		
+		return GenerateRandomNumber<T>(std::numeric_limits<T>::min(), std::numeric_limits<T>::max());
+	}
 }

dNet/AuthPackets.cpp

@@ -8,6 +8,7 @@
 #include "ZoneInstanceManager.h"
 #include "MD5.h"
 #include "SHA512.h"
+#include "GeneralUtils.h"
 
 #ifdef _WIN32
 #include <bcrypt/BCrypt.hpp>
@@ -211,7 +212,7 @@ void AuthPackets::SendLoginResponse(dServer* server, const SystemAddress& sysAdd
 	packet.Write(static_cast<uint16_t>(64));        // Version Minor
 
 	// Writes the user key
-	uint32_t sessionKey = rand(); // not mt but whatever
+	uint32_t sessionKey = GeneralUtils::GenerateRandomNumber<uint32_t>();
 	std::string userHash = std::to_string(sessionKey);
 	userHash = md5(userHash);
 	PacketUtils::WritePacketWString(userHash, 33, &packet);