add simple noclip cheating detection

init.lua

@@ -64,6 +64,7 @@ if beerchat.http then
 
 	dofile(MP.."/web/executor.lua")
 	dofile(MP.."/web/tx.lua")
+	dofile(MP.."/web/audit.lua")
 	dofile(MP.."/web/rx.lua")
 	dofile(MP.."/web/login.lua")
 	dofile(MP.."/web/logout.lua")

web/audit.lua

@@ -0,0 +1,65 @@
+-- auth fail
+minetest.register_on_auth_fail(function(name, ip)
+	beerchat.on_channel_message("audit", nil, "Player '" .. name ..
+		"' from ip " .. ip .. " tried to connect with wrong password")
+end)
+
+-- anticheat
+minetest.register_on_cheat(function(player, cheat)
+	local playername = player:get_player_name()
+	local type = cheat.type
+	beerchat.on_channel_message("audit", nil, "Player '" .. playername ..
+		"' triggered anticheat: '" .. (type or "<unknown>") ..
+		"' at position: " .. minetest.pos_to_string(vector.floor(player:get_pos())))
+end)
+
+-- noclip check
+
+local solid_nodes = {
+  ["default:stone"] = true,
+  ["default:sand"] = true,
+  ["default:gravel"] = true
+}
+
+-- playername -> count
+local noclip_counters = {}
+
+-- set counter
+minetest.register_on_joinplayer(function(player)
+  noclip_counters[player:get_player_name()] = 0
+end)
+
+-- clear counter
+minetest.register_on_leaveplayer(function(player)
+  noclip_counters[player:get_player_name()] = nil
+end)
+
+-- check players
+local function check_player_node()
+  for _, player in ipairs(minetest.get_connected_players()) do
+    if not minetest.check_player_privs(player:get_player_name(), "noclip") then
+      -- noclip not granted
+      local pos = player:get_pos()
+      local playername = player:get_player_name()
+      local node = minetest.get_node(pos)
+      if node.name and solid_nodes[node.name] then
+        noclip_counters[playername] = noclip_counters[playername] + 1
+
+        if noclip_counters[playername] > 10 then
+          -- report possible clientside noclip cheat
+          local msg = "Player '" .. playername .. "' " ..
+            " was caught inside a solid node" ..
+            " last at position: " .. minetest.pos_to_string(vector.floor(player:get_pos()))
+          beerchat.on_channel_message("audit", nil, msg)
+          minetest.log("action", "[beerchat audit] " .. msg)
+
+          noclip_counters[playername] = 0
+        end
+      end
+    end
+  end
+
+  minetest.after(1, check_player_node)
+end
+
+minetest.after(1, check_player_node)

web/tx.lua

@@ -85,18 +85,3 @@ beerchat.on_channel_message(nil, nil, "Minetest started!")
 minetest.register_on_shutdown(function()
 	beerchat.on_channel_message(nil, nil, "Minetest shutting down!")
 end)
-
--- auth fail
-minetest.register_on_auth_fail(function(name, ip)
-	beerchat.on_channel_message("audit", nil, "Player '" .. name ..
-		"' from ip " .. ip .. " tried to connect with wrong password")
-end)
-
--- anticheat
-minetest.register_on_cheat(function(player, cheat)
-	local playername = player:get_player_name()
-	local type = cheat.type
-	beerchat.on_channel_message("audit", nil, "Player '" .. playername ..
-		"' triggered anticheat: '" .. (type or "<unknown>") ..
-		"' at position: " .. minetest.pos_to_string(vector.floor(player:get_pos())))
-end)