Experimental Fix for Recent Flood Attack

[Reached 815]

They're crashing the game by sending randomly sized packets during the handshake/login phase, inflating the buffer size from different connections.

A 65kb buffer is opened for each connection.

m_lpInputBuffer = buffer_new(MAX_INPUT_LEN);

When this buffer is filled with many connections from different designs, the channel reaches its 4gb memory limit and crashes.

The change we made checks the total bytes received from the session during handshake and login (When simulated, the total data flow is 1.25kb max @ Koray <3) and bans the IP if it exceeds the potential data to be received. A host will also get banned if it receives more connections than the limit we set.

Forgotten part: desc.cpp

//Search

    SetPhase(PHASE_HANDSHAKE);

    StartHandshake(_handshake);


// Add above


    {
        desc_event_info* timeout_info = AllocEventInfo<desc_event_info>();
        timeout_info->desc = this;
        m_pkPhaseTimeoutEvent = event_create(phase_timeout_event, timeout_info, PASSES_PER_SEC(DESC_HANDSHAKE_TIMEOUT_SEC));
    }


// Search

m_pInputProcessor = &m_inputMain;


// Add under
event_cancel(&m_pkPhaseTimeoutEvent);
DESC_MANAGER::instance().DecUnauthCount(this);

 

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Alternative download links → Alternate_1 or Alternate_2 or Alternate_3

 

 

Edited March 1 by Reached