From e094942b75117a49cae8c35d6508f37d0cf511fe Mon Sep 17 00:00:00 2001
From: Nico <122193236+Nico8340@users.noreply.github.com>
Date: Thu, 21 Nov 2024 23:14:34 +0100
Subject: [PATCH] Check if another player has the same serial (#3854)

---
 Client/mods/deathmatch/logic/CPacketHandler.cpp   |  4 ++++
 Client/mods/deathmatch/logic/CPacketHandler.h     |  3 ++-
 Server/mods/deathmatch/editor.conf                |  6 ++++++
 Server/mods/deathmatch/local.conf                 |  6 ++++++
 Server/mods/deathmatch/logic/CGame.cpp            | 15 +++++++++++++++
 Server/mods/deathmatch/logic/CMainConfig.cpp      |  2 ++
 Server/mods/deathmatch/logic/CMainConfig.h        |  2 ++
 Server/mods/deathmatch/logic/CPlayerManager.cpp   | 11 +++++++++++
 Server/mods/deathmatch/logic/CPlayerManager.h     |  1 +
 .../logic/packets/CPlayerDisconnectedPacket.h     |  3 ++-
 Server/mods/deathmatch/mtaserver.conf             |  6 ++++++
 Server/mods/deathmatch/mtaserver.conf.template    |  6 ++++++
 Shared/sdk/net/bitstream.h                        |  4 ++++
 13 files changed, 67 insertions(+), 2 deletions(-)

diff --git a/Client/mods/deathmatch/logic/CPacketHandler.cpp b/Client/mods/deathmatch/logic/CPacketHandler.cpp
index ebf2ba5140..3142a6e4d2 100644
--- a/Client/mods/deathmatch/logic/CPacketHandler.cpp
+++ b/Client/mods/deathmatch/logic/CPacketHandler.cpp
@@ -572,6 +572,10 @@ void CPacketHandler::Packet_ServerDisconnected(NetBitStreamInterface& bitStream)
             strReason = _("Disconnected: Serial verification failed");
             strErrorCode = _E("CD44");
             break;
+        case ePlayerDisconnectType::SERIAL_DUPLICATE:
+            strReason = _("Disconnected: Serial already in use");
+            strErrorCode = _E("CD50");
+            break;
         case ePlayerDisconnectType::CONNECTION_DESYNC:
             strReason = _("Disconnected: Connection desync %s");
             strErrorCode = _E("CD45");
diff --git a/Client/mods/deathmatch/logic/CPacketHandler.h b/Client/mods/deathmatch/logic/CPacketHandler.h
index ca0f6f3d69..9a50b24615 100644
--- a/Client/mods/deathmatch/logic/CPacketHandler.h
+++ b/Client/mods/deathmatch/logic/CPacketHandler.h
@@ -42,7 +42,8 @@ class CPacketHandler
         BAN,
         KICK,
         CUSTOM,
-        SHUTDOWN
+        SHUTDOWN,
+        SERIAL_DUPLICATE
     };
 
     struct SEntityDependantStuff
diff --git a/Server/mods/deathmatch/editor.conf b/Server/mods/deathmatch/editor.conf
index 3b2b75fa80..1355e673ee 100644
--- a/Server/mods/deathmatch/editor.conf
+++ b/Server/mods/deathmatch/editor.conf
@@ -268,6 +268,12 @@
           Values: 0 - Off, 1 - Enabled.  Default - 1 -->
     <resource_client_file_checks>1</resource_client_file_checks>
 
+    <!-- This parameter determines that the server checks when the players connect that there are no other players with the same serial number. 
+         Note that this may break compatibility with virtual machines.
+         Not guarantees that the player cannot manipulate their serial.
+         Values: 0 - Off, 1 - Enabled.  Default - 1 -->
+    <check_duplicate_serials>1</check_duplicate_serials>
+
     <!-- Specifies the module(s) which are loaded with the server. To load several modules, add more <module>
          parameter(s). Optional parameter. -->
     <!-- <module src="sample_win32.dll"/> -->
diff --git a/Server/mods/deathmatch/local.conf b/Server/mods/deathmatch/local.conf
index 039e155d81..d30a608781 100644
--- a/Server/mods/deathmatch/local.conf
+++ b/Server/mods/deathmatch/local.conf
@@ -274,6 +274,12 @@
          Values: 0 - Off, 1 - Enabled.  Default - 0 -->
     <elementdata_whitelisted>0</elementdata_whitelisted>
 
+    <!-- This parameter determines that the server checks when the players connect that there are no other players with the same serial number. 
+         Note that this may break compatibility with virtual machines.
+         Not guarantees that the player cannot manipulate their serial.
+         Values: 0 - Off, 1 - Enabled.  Default - 1 -->
+    <check_duplicate_serials>1</check_duplicate_serials>
+
     <!-- Specifies the module(s) which are loaded with the server. To load several modules, add more <module>
          parameter(s). Optional parameter. -->
     <!-- <module src="sample_win32.dll"/> -->
diff --git a/Server/mods/deathmatch/logic/CGame.cpp b/Server/mods/deathmatch/logic/CGame.cpp
index 9543e1e447..a72885c929 100644
--- a/Server/mods/deathmatch/logic/CGame.cpp
+++ b/Server/mods/deathmatch/logic/CGame.cpp
@@ -1798,6 +1798,21 @@ void CGame::Packet_PlayerJoinData(CPlayerJoinDataPacket& Packet)
             return;
         }
 
+        // Check if another player is using the same serial
+        if (m_pMainConfig->IsCheckDuplicateSerialsEnabled() && m_pPlayerManager->GetBySerial(strSerial))
+        {
+            // Tell the console
+            CLogger::LogPrintf("CONNECT: %s failed to connect (Serial already in use) (%s)\n", szNick, strIPAndSerial.c_str());
+
+            // Tell the player the problem
+            if (pPlayer->CanBitStream(eBitStreamVersion::CheckDuplicateSerials))
+                DisconnectPlayer(this, *pPlayer, CPlayerDisconnectedPacket::SERIAL_DUPLICATE);
+            else
+                DisconnectPlayer(this, *pPlayer, CPlayerDisconnectedPacket::KICK);
+
+            return;
+        }
+
         // Check the nick is valid
         if (!CheckNickProvided(szNick))
         {
diff --git a/Server/mods/deathmatch/logic/CMainConfig.cpp b/Server/mods/deathmatch/logic/CMainConfig.cpp
index bece65e885..49c73419ca 100644
--- a/Server/mods/deathmatch/logic/CMainConfig.cpp
+++ b/Server/mods/deathmatch/logic/CMainConfig.cpp
@@ -80,6 +80,7 @@ CMainConfig::CMainConfig(CConsole* pConsole) : CXMLConfig(NULL)
     m_iBackupAmount = 5;
     m_bSyncMapElementData = true;
     m_elementDataWhitelisted = false;
+    m_checkDuplicateSerials = true;
 }
 
 bool CMainConfig::Load()
@@ -528,6 +529,7 @@ bool CMainConfig::Load()
     }
 
     GetBoolean(m_pRootNode, "elementdata_whitelisted", m_elementDataWhitelisted);
+    GetBoolean(m_pRootNode, "check_duplicate_serials", m_checkDuplicateSerials);
 
     ApplyNetOptions();
 
diff --git a/Server/mods/deathmatch/logic/CMainConfig.h b/Server/mods/deathmatch/logic/CMainConfig.h
index 9758ae2dbf..05df0e2f32 100644
--- a/Server/mods/deathmatch/logic/CMainConfig.h
+++ b/Server/mods/deathmatch/logic/CMainConfig.h
@@ -127,6 +127,7 @@ class CMainConfig : public CXMLConfig
     bool                        IsDatabaseCredentialsProtectionEnabled() const { return m_bDatabaseCredentialsProtectionEnabled != 0; }
     bool                        IsFakeLagCommandEnabled() const { return m_bFakeLagCommandEnabled != 0; }
     bool                        IsElementDataWhitelisted() const { return m_elementDataWhitelisted; }
+    bool                        IsCheckDuplicateSerialsEnabled() const noexcept { return m_checkDuplicateSerials; }
     bool                        IsCheckResourceClientFilesEnabled() const noexcept { return m_checkResourceClientFiles != 0; }
 
     SString GetSetting(const SString& configSetting);
@@ -230,5 +231,6 @@ class CMainConfig : public CXMLConfig
     int                        m_iPlayerTriggeredEventIntervalMs;
     int                        m_iMaxPlayerTriggeredEventsPerInterval;
     bool                       m_elementDataWhitelisted;
+    bool                       m_checkDuplicateSerials;
     int                        m_checkResourceClientFiles;
 };
diff --git a/Server/mods/deathmatch/logic/CPlayerManager.cpp b/Server/mods/deathmatch/logic/CPlayerManager.cpp
index abdf923df7..227d3677f2 100644
--- a/Server/mods/deathmatch/logic/CPlayerManager.cpp
+++ b/Server/mods/deathmatch/logic/CPlayerManager.cpp
@@ -138,6 +138,17 @@ CPlayer* CPlayerManager::Get(const char* szNick, bool bCaseSensitive)
     return NULL;
 }
 
+CPlayer* CPlayerManager::GetBySerial(const std::string_view serial) const noexcept
+{
+    for (const auto& player : m_Players)
+    {
+        if (player->GetSerial() == serial)
+            return player;
+    }
+
+    return nullptr;
+}
+
 void CPlayerManager::DeleteAll()
 {
     // Delete all the items in the list
diff --git a/Server/mods/deathmatch/logic/CPlayerManager.h b/Server/mods/deathmatch/logic/CPlayerManager.h
index bd503380f4..0380c4bce4 100644
--- a/Server/mods/deathmatch/logic/CPlayerManager.h
+++ b/Server/mods/deathmatch/logic/CPlayerManager.h
@@ -40,6 +40,7 @@ class CPlayerManager
 
     CPlayer* Get(const NetServerPlayerID& PlayerSocket);
     CPlayer* Get(const char* szNick, bool bCaseSensitive = false);
+    CPlayer* GetBySerial(const std::string_view serial) const noexcept;
 
     std::list<CPlayer*>::const_iterator IterBegin() { return m_Players.begin(); };
     std::list<CPlayer*>::const_iterator IterEnd() { return m_Players.end(); };
diff --git a/Server/mods/deathmatch/logic/packets/CPlayerDisconnectedPacket.h b/Server/mods/deathmatch/logic/packets/CPlayerDisconnectedPacket.h
index 82fdfbd1b0..541f9b191c 100644
--- a/Server/mods/deathmatch/logic/packets/CPlayerDisconnectedPacket.h
+++ b/Server/mods/deathmatch/logic/packets/CPlayerDisconnectedPacket.h
@@ -39,7 +39,8 @@ class CPlayerDisconnectedPacket final : public CPacket
         BAN,
         KICK,
         CUSTOM,
-        SHUTDOWN
+        SHUTDOWN,
+        SERIAL_DUPLICATE
     };
 
     CPlayerDisconnectedPacket(const char* szReason);
diff --git a/Server/mods/deathmatch/mtaserver.conf b/Server/mods/deathmatch/mtaserver.conf
index 11ef497fa7..726199d548 100644
--- a/Server/mods/deathmatch/mtaserver.conf
+++ b/Server/mods/deathmatch/mtaserver.conf
@@ -274,6 +274,12 @@
          Values: 0 - Off, 1 - Enabled.  Default - 0 -->
     <elementdata_whitelisted>0</elementdata_whitelisted>
 
+    <!-- This parameter determines that the server checks when the players connect that there are no other players with the same serial number. 
+         Note that this may break compatibility with virtual machines.
+         Not guarantees that the player cannot manipulate their serial.
+         Values: 0 - Off, 1 - Enabled.  Default - 1 -->
+    <check_duplicate_serials>1</check_duplicate_serials>
+
     <!-- These parameters specify the maximum amount of events that can be triggered by the client (via triggerServerEvent) within the given interval.
           Note: The interval is given in milliseconds
           Interval range: 50 to 5000. Default: 1000
diff --git a/Server/mods/deathmatch/mtaserver.conf.template b/Server/mods/deathmatch/mtaserver.conf.template
index 88288cc9d6..13237b1b10 100644
--- a/Server/mods/deathmatch/mtaserver.conf.template
+++ b/Server/mods/deathmatch/mtaserver.conf.template
@@ -275,6 +275,12 @@
          Values: 0 - Off, 1 - Enabled.  Default - 0 -->
     <elementdata_whitelisted>0</elementdata_whitelisted>
 
+    <!-- This parameter determines that the server checks when the players connect that there are no other players with the same serial number. 
+         Note that this may break compatibility with virtual machines.
+         Not guarantees that the player cannot manipulate their serial.
+         Values: 0 - Off, 1 - Enabled.  Default - 1 -->
+    <check_duplicate_serials>1</check_duplicate_serials>
+
     <!-- These parameters specify the maximum amount of events that can be triggered by the client (via triggerServerEvent) within the given interval.
           Note: The interval is given in milliseconds
           Interval range: 50 to 5000. Default: 1000
diff --git a/Shared/sdk/net/bitstream.h b/Shared/sdk/net/bitstream.h
index c29f739ff1..4dde7f3782 100644
--- a/Shared/sdk/net/bitstream.h
+++ b/Shared/sdk/net/bitstream.h
@@ -572,6 +572,10 @@ enum class eBitStreamVersion : unsigned short
     // 2024-09-04
     RespawnObject_Serverside,
 
+    // Add check_duplicate_serials
+    // 2024-09-04
+    CheckDuplicateSerials,
+
     // This allows us to automatically increment the BitStreamVersion when things are added to this enum.
     // Make sure you only add things above this comment.
     Next,