Core/WorldSession: Mitigate DoS attacks

Mitigate DoS attacks like one explained in #10555 by processing a limited number of packets at each WorldSession::Update() call, allowing other WorldSessions to be processed.
100 packets in a single update sound like a reasonable amount.

1 files changed, 10 insertions, 0 deletions

diff --git a/src/server/game/Server/WorldSession.cpp b/src/server/game/Server/WorldSession.cpp
index 75da92158d1..c33c12ae5d4 100644
--- a/src/server/game/Server/WorldSession.cpp
+++ b/src/server/game/Server/WorldSession.cpp
@@ -272,6 +272,8 @@ bool WorldSession::Update(uint32 diff, PacketFilter& updater)
     //! delayed packets that were re-enqueued due to improper timing. To prevent an infinite
     //! loop caused by re-enqueueing the same packets over and over again, we stop updating this session
     //! and continue updating others. The re-enqueued packets will be handled in the next Update call for this session.
+    uint32 processedPackets = 0;
+
     while (m_Socket && !m_Socket->IsClosed() &&
             !_recvQueue.empty() && _recvQueue.peek(true) != firstDelayedPacket &&
             _recvQueue.next(packet, updater))
@@ -383,6 +385,14 @@ bool WorldSession::Update(uint32 diff, PacketFilter& updater)
             delete packet;
 
         deletePacket = true;
+
+#define MAX_PROCESSED_PACKETS_IN_SAME_WORLDSESSION_UPDATE 100
+        processedPackets++;
+
+        //process only a max amout of packets in 1 Update() call.
+        //Any leftover will be processed in next update
+        if (processedPackets > MAX_PROCESSED_PACKETS_IN_SAME_WORLDSESSION_UPDATE)
+            break;
     }
 
     if (m_Socket && !m_Socket->IsClosed() && _warden)