Block attempts to connect to the client (#10589)

A Minetest peer initiates a connection by sending a packet with an invalid peer_id, for whatever reason the code for doing this ran on both the client and the server meaning you could connect to a client if you knew what the address:port tuple it was listening on.

1 files changed, 4 insertions, 1 deletions

diff --git a/src/network/connectionthreads.cpp b/src/network/connectionthreads.cpp
index 28ed798d9..7b62bc792 100644
--- a/src/network/connectionthreads.cpp
+++ b/src/network/connectionthreads.cpp
@@ -956,8 +956,11 @@ void ConnectionReceiveThread::receive(SharedBuffer<u8> &packetdata,
 			// command was sent reliably.
 		}
 
-		/* The peer was not found in our lists. Add it. */
 		if (peer_id == PEER_ID_INEXISTENT) {
+			/* Ignore it if we are a client */
+			if (m_connection->ConnectedToServer())
+				return;
+			/* The peer was not found in our lists. Add it. */
 			peer_id = m_connection->createPeer(sender, MTP_MINETEST_RELIABLE_UDP, 0);
 		}