From d4c76258e37337ea585cf24d8e05b50a30fa307d Mon Sep 17 00:00:00 2001
From: Loic Blot <loic.blot@unix-experience.fr>
Date: Tue, 4 Oct 2016 18:17:12 +0200
Subject: [PATCH] Chat: new settings to prevent spam
Added the following chat coreside features
* Chat messages length limit
* Message rate limiting
* Message rate kicking
Note:
* handleChat now takes RemotePlayer pointer instead of u16 to remove useless
lookups
---
builtin/settingtypes.txt | 9 +++++
minetest.conf.example | 14 +++++++-
src/defaultsettings.cpp | 3 ++
src/network/serverpackethandler.cpp | 10 +++---
src/player.cpp | 56 ++++++++++++++++++++++++++++-
src/player.h | 16 ++++++++-
src/server.cpp | 25 +++++++++++--
src/server.h | 3 +-
8 files changed, 125 insertions(+), 11 deletions(-)
diff --git a/builtin/settingtypes.txt b/builtin/settingtypes.txt
index 15fab0f30..95cc826a0 100644
--- a/builtin/settingtypes.txt
+++ b/builtin/settingtypes.txt
@@ -774,6 +774,15 @@ time_speed (Time speed) int 72
# Interval of saving important changes in the world, stated in seconds.
server_map_save_interval (Map save interval) float 5.3
+# Set the maximum character length of a chat message sent by clients.
+# chat_message_max_size int 500
+
+# Limit a single player to send X messages per 10 seconds.
+# chat_message_limit_per_10sec float 10.0
+
+# Kick player if send more than X messages per 10 seconds.
+# chat_message_limit_trigger_kick int 50
+
[**Physics]
movement_acceleration_default (Default acceleration) float 3
diff --git a/minetest.conf.example b/minetest.conf.example
index 9c8015625..b1b202786 100644
--- a/minetest.conf.example
+++ b/minetest.conf.example
@@ -933,6 +933,18 @@
# type: float
# server_map_save_interval = 5.3
+# Set the maximum character length of a chat message sent by clients. (0 to disable)
+# type: integer
+# chat_message_max_size = 500
+
+# Limit a single player to send X messages per 10 seconds. (0 to disable)
+# type: float
+# chat_message_limit_per_10sec = 8.0
+
+# Kick player if send more than X messages per 10 seconds. (0 to disable)
+# type: integer
+# chat_message_limit_trigger_kick = 50
+
### Physics
# type: float
@@ -1523,7 +1535,7 @@
# profiler.default_report_format = txt
# The file path relative to your worldpath in which profiles will be saved to.
-#
+#
# type: string
# profiler.report_path = ""
diff --git a/src/defaultsettings.cpp b/src/defaultsettings.cpp
index 4520bac2f..00c233a42 100644
--- a/src/defaultsettings.cpp
+++ b/src/defaultsettings.cpp
@@ -285,6 +285,9 @@ void set_default_settings(Settings *settings)
settings->setDefault("server_unload_unused_data_timeout", "29");
settings->setDefault("max_objects_per_block", "49");
settings->setDefault("server_map_save_interval", "5.3");
+ settings->setDefault("chat_message_max_size", "500");
+ settings->setDefault("chat_message_limit_per_10sec", "8.0");
+ settings->setDefault("chat_message_limit_trigger_kick", "50");
settings->setDefault("sqlite_synchronous", "2");
settings->setDefault("full_block_send_enable_min_time_from_building", "2.0");
settings->setDefault("dedicated_server_step", "0.1");
diff --git a/src/network/serverpackethandler.cpp b/src/network/serverpackethandler.cpp
index 1bcb78a8a..a8bfd9068 100644
--- a/src/network/serverpackethandler.cpp
+++ b/src/network/serverpackethandler.cpp
@@ -1065,7 +1065,7 @@ void Server::handleCommand_ChatMessage(NetworkPacket* pkt)
std::wstring wname = narrow_to_wide(name);
std::wstring answer_to_sender = handleChat(name, wname, message,
- true, pkt->getPeerId());
+ true, dynamic_cast<RemotePlayer *>(player));
if (!answer_to_sender.empty()) {
// Send the answer to sender
SendChatMessage(pkt->getPeerId(), answer_to_sender);
@@ -1656,16 +1656,16 @@ void Server::handleCommand_Interact(NetworkPacket* pkt)
}
} // action == 4
-
+
/*
5: rightclick air
*/
else if (action == 5) {
ItemStack item = playersao->getWieldedItem();
-
- actionstream << player->getName() << " activates "
+
+ actionstream << player->getName() << " activates "
<< item.name << std::endl;
-
+
if (m_script->item_OnSecondaryUse(
item, playersao)) {
if( playersao->setWieldedItem(item)) {
diff --git a/src/player.cpp b/src/player.cpp
index 5949712a5..fd72d63b6 100644
--- a/src/player.cpp
+++ b/src/player.cpp
@@ -227,10 +227,25 @@ void Player::clearHud()
}
}
+// static config cache for remoteplayer
+bool RemotePlayer::m_setting_cache_loaded = false;
+float RemotePlayer::m_setting_chat_message_limit_per_10sec = 0.0f;
+u16 RemotePlayer::m_setting_chat_message_limit_trigger_kick = 0;
+
RemotePlayer::RemotePlayer(IGameDef *gamedef, const char *name):
Player(gamedef, name),
- m_sao(NULL)
+ m_sao(NULL),
+ m_last_chat_message_sent(time(NULL)),
+ m_chat_message_allowance(5.0f),
+ m_message_rate_overhead(0)
{
+ if (!RemotePlayer::m_setting_cache_loaded) {
+ RemotePlayer::m_setting_chat_message_limit_per_10sec =
+ g_settings->getFloat("chat_message_limit_per_10sec");
+ RemotePlayer::m_setting_chat_message_limit_trigger_kick =
+ g_settings->getU16("chat_message_limit_trigger_kick");
+ RemotePlayer::m_setting_cache_loaded = true;
+ }
movement_acceleration_default = g_settings->getFloat("movement_acceleration_default") * BS;
movement_acceleration_air = g_settings->getFloat("movement_acceleration_air") * BS;
movement_acceleration_fast = g_settings->getFloat("movement_acceleration_fast") * BS;
@@ -304,3 +319,42 @@ void RemotePlayer::setPosition(const v3f &position)
m_sao->setBasePosition(position);
}
+const RemotePlayerChatResult RemotePlayer::canSendChatMessage()
+{
+ // Rate limit messages
+ u32 now = time(NULL);
+ float time_passed = now - m_last_chat_message_sent;
+ m_last_chat_message_sent = now;
+
+ // If this feature is disabled
+ if (m_setting_chat_message_limit_per_10sec <= 0.0) {
+ return RPLAYER_CHATRESULT_OK;
+ }
+
+ m_chat_message_allowance += time_passed * (m_setting_chat_message_limit_per_10sec / 8.0f);
+ if (m_chat_message_allowance > m_setting_chat_message_limit_per_10sec) {
+ m_chat_message_allowance = m_setting_chat_message_limit_per_10sec;
+ }
+
+ if (m_chat_message_allowance < 1.0f) {
+ infostream << "Player " << m_name
+ << " chat limited due to excessive message amount." << std::endl;
+
+ // Kick player if flooding is too intensive
+ m_message_rate_overhead++;
+ if (m_message_rate_overhead > RemotePlayer::m_setting_chat_message_limit_trigger_kick) {
+ return RPLAYER_CHATRESULT_KICK;
+ }
+
+ return RPLAYER_CHATRESULT_FLOODING;
+ }
+
+ // Reinit message overhead
+ if (m_message_rate_overhead > 0) {
+ m_message_rate_overhead = 0;
+ }
+
+ m_chat_message_allowance -= 1.0f;
+ return RPLAYER_CHATRESULT_OK;
+}
+
diff --git a/src/player.h b/src/player.h
index eab00bb04..f38effa9d 100644
--- a/src/player.h
+++ b/src/player.h
@@ -439,7 +439,11 @@ class Player
Mutex m_mutex;
};
-
+enum RemotePlayerChatResult {
+ RPLAYER_CHATRESULT_OK,
+ RPLAYER_CHATRESULT_FLOODING,
+ RPLAYER_CHATRESULT_KICK,
+};
/*
Player on the server
*/
@@ -457,8 +461,18 @@ class RemotePlayer : public Player
{ m_sao = sao; }
void setPosition(const v3f &position);
+ const RemotePlayerChatResult canSendChatMessage();
+
private:
PlayerSAO *m_sao;
+
+ static bool m_setting_cache_loaded;
+ static float m_setting_chat_message_limit_per_10sec;
+ static u16 m_setting_chat_message_limit_trigger_kick;
+
+ u32 m_last_chat_message_sent;
+ float m_chat_message_allowance;
+ u16 m_message_rate_overhead;
};
#endif
diff --git a/src/server.cpp b/src/server.cpp
index fb241f179..c615aee13 100644
--- a/src/server.cpp
+++ b/src/server.cpp
@@ -358,6 +358,7 @@ Server::Server(
add_legacy_abms(m_env, m_nodedef);
m_liquid_transform_every = g_settings->getFloat("liquid_update");
+ m_max_chatmessage_length = g_settings->getU16("chat_message_max_size");
}
Server::~Server()
@@ -2734,8 +2735,7 @@ void Server::handleChatInterfaceEvent(ChatEvent *evt)
}
std::wstring Server::handleChat(const std::string &name, const std::wstring &wname,
- const std::wstring &wmessage, bool check_shout_priv,
- u16 peer_id_to_avoid_sending)
+ const std::wstring &wmessage, bool check_shout_priv, RemotePlayer *player)
{
// If something goes wrong, this player is to blame
RollbackScopeActor rollback_scope(m_rollback,
@@ -2753,6 +2753,26 @@ std::wstring Server::handleChat(const std::string &name, const std::wstring &wna
if (ate)
return L"";
+ switch (player->canSendChatMessage()) {
+ case RPLAYER_CHATRESULT_FLOODING: {
+ std::wstringstream ws;
+ ws << L"You cannot send more messages. You are limited to "
+ << g_settings->getFloat("chat_message_limit_per_10sec")
+ << " messages per 10 seconds.";
+ return ws.str();
+ }
+ case RPLAYER_CHATRESULT_KICK:
+ DenyAccess_Legacy(player->peer_id, L"You have been kicked due to message flooding.");
+ return L"";
+ case RPLAYER_CHATRESULT_OK: break;
+ default: FATAL_ERROR("Unhandled chat filtering result found.");
+ }
+
+ if (m_max_chatmessage_length > 0 && wmessage.length() > m_max_chatmessage_length) {
+ return L"Your message exceed the maximum chat message limit set on the server. "
+ "It was refused. Send a shorter message";
+ }
+
// Commands are implemented in Lua, so only catch invalid
// commands that were not "eaten" and send an error back
if (wmessage[0] == L'/') {
@@ -2787,6 +2807,7 @@ std::wstring Server::handleChat(const std::string &name, const std::wstring &wna
std::vector<u16> clients = m_clients.getClientIDs();
+ u16 peer_id_to_avoid_sending = (player ? player->peer_id : PEER_ID_INEXISTENT);
for (u16 i = 0; i < clients.size(); i++) {
u16 cid = clients[i];
if (cid != peer_id_to_avoid_sending)
diff --git a/src/server.h b/src/server.h
index 7ee15a463..3ad894b38 100644
--- a/src/server.h
+++ b/src/server.h
@@ -487,7 +487,7 @@ class Server : public con::PeerHandler, public MapEventReceiver,
std::wstring handleChat(const std::string &name, const std::wstring &wname,
const std::wstring &wmessage,
bool check_shout_priv = false,
- u16 peer_id_to_avoid_sending = PEER_ID_INEXISTENT);
+ RemotePlayer *player = NULL);
void handleAdminChat(const ChatEventChat *evt);
v3f findSpawnPos();
@@ -522,6 +522,7 @@ class Server : public con::PeerHandler, public MapEventReceiver,
// If true, do not allow multiple players and hide some multiplayer
// functionality
bool m_simple_singleplayer_mode;
+ u16 m_max_chatmessage_length;
// Thread can set; step() will throw as ServerError
MutexedVariable<std::string> m_async_fatal_error;
--
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