From eabf04bd34b840ee3359609fc977cf4795b33a3a Mon Sep 17 00:00:00 2001
From: Loic Blot <loic.blot@unix-experience.fr>
Date: Sun, 3 Sep 2017 19:01:53 +0200
Subject: [PATCH] Network part requires SharedBuffers to be pass as value This
 can trigger unreproductible crashes due to concurrency problem on
 SharedBuffers

This fixes #6354
---
 src/network/connection.cpp        | 8 +++-----
 src/network/connection.h          | 6 +++---
 src/network/connectionthreads.cpp | 2 +-
 src/network/connectionthreads.h   | 2 +-
 4 files changed, 8 insertions(+), 10 deletions(-)

diff --git a/src/network/connection.cpp b/src/network/connection.cpp
index 01f1a7e63..b2e443901 100644
--- a/src/network/connection.cpp
+++ b/src/network/connection.cpp
@@ -55,7 +55,7 @@ std::mutex log_message_mutex;
 
 #define PING_TIMEOUT 5.0
 
-BufferedPacket makePacket(Address &address, const SharedBuffer<u8> &data,
+BufferedPacket makePacket(Address &address, SharedBuffer<u8> data,
 		u32 protocol_id, u16 sender_peer_id, u8 channel)
 {
 	u32 packet_size = data.getSize() + BASE_HEADER_SIZE;
@@ -125,7 +125,7 @@ void makeSplitPacket(const SharedBuffer<u8> &data, u32 chunksize_max, u16 seqnum
 	}
 }
 
-void makeAutoSplitPacket(const SharedBuffer<u8> &data, u32 chunksize_max,
+void makeAutoSplitPacket(SharedBuffer<u8> data, u32 chunksize_max,
 		u16 &split_seqnum, std::list<SharedBuffer<u8>> *list)
 {
 	u32 original_header_size = 1;
@@ -139,9 +139,7 @@ void makeAutoSplitPacket(const SharedBuffer<u8> &data, u32 chunksize_max,
 	list->push_back(makeOriginalPacket(data));
 }
 
-SharedBuffer<u8> makeReliablePacket(
-		const SharedBuffer<u8> &data,
-		u16 seqnum)
+SharedBuffer<u8> makeReliablePacket(SharedBuffer<u8> data, u16 seqnum)
 {
 	u32 header_size = 3;
 	u32 packet_size = data.getSize() + header_size;
diff --git a/src/network/connection.h b/src/network/connection.h
index c54161cc9..e1bb613f0 100644
--- a/src/network/connection.h
+++ b/src/network/connection.h
@@ -102,16 +102,16 @@ struct BufferedPacket
 };
 
 // This adds the base headers to the data and makes a packet out of it
-BufferedPacket makePacket(Address &address, const SharedBuffer<u8> &data,
+BufferedPacket makePacket(Address &address, SharedBuffer<u8> data,
 		u32 protocol_id, u16 sender_peer_id, u8 channel);
 
 // Depending on size, make a TYPE_ORIGINAL or TYPE_SPLIT packet
 // Increments split_seqnum if a split packet is made
-void makeAutoSplitPacket(const SharedBuffer<u8> &data, u32 chunksize_max,
+void makeAutoSplitPacket(SharedBuffer<u8> data, u32 chunksize_max,
 		u16 &split_seqnum, std::list<SharedBuffer<u8>> *list);
 
 // Add the TYPE_RELIABLE header to the data
-SharedBuffer<u8> makeReliablePacket(const SharedBuffer<u8> &data, u16 seqnum);
+SharedBuffer<u8> makeReliablePacket(SharedBuffer<u8> data, u16 seqnum);
 
 struct IncomingSplitPacket
 {
diff --git a/src/network/connectionthreads.cpp b/src/network/connectionthreads.cpp
index 63c1855c5..ec09e9d3e 100644
--- a/src/network/connectionthreads.cpp
+++ b/src/network/connectionthreads.cpp
@@ -330,7 +330,7 @@ void ConnectionSendThread::sendAsPacketReliable(BufferedPacket &p, Channel *chan
 }
 
 bool ConnectionSendThread::rawSendAsPacket(u16 peer_id, u8 channelnum,
-	const SharedBuffer<u8> &data, bool reliable)
+	SharedBuffer<u8> data, bool reliable)
 {
 	PeerHelper peer = m_connection->getPeerNoEx(peer_id);
 	if (!peer) {
diff --git a/src/network/connectionthreads.h b/src/network/connectionthreads.h
index c2314f87f..906866468 100644
--- a/src/network/connectionthreads.h
+++ b/src/network/connectionthreads.h
@@ -52,7 +52,7 @@ public:
 private:
 	void runTimeouts(float dtime);
 	void rawSend(const BufferedPacket &packet);
-	bool rawSendAsPacket(u16 peer_id, u8 channelnum, const SharedBuffer<u8> &data,
+	bool rawSendAsPacket(u16 peer_id, u8 channelnum, SharedBuffer<u8> data,
 			bool reliable);
 
 	void processReliableCommand(ConnectionCommand &c);