Server enforcement for fog_distance (minetest#13448) to block cheating (

minetest#13643)

This enforces the fog_distance (if set) at the server, so that a hacked client could not cheat and retrieve blocks beyond the set distance.

src/clientiface.cpp

@@ -180,7 +180,12 @@ void RemoteClient::GetNextBlocks (
 	s32 new_nearest_unsent_d = -1;
 
 	// Get view range and camera fov (radians) from the client
+	s16 fog_distance = sao->getPlayer()->getSkyParams().fog_distance;
 	s16 wanted_range = sao->getWantedRange() + 1;
+	if (fog_distance >= 0) {
+		// enforce if limited by mod
+		wanted_range = std::min<unsigned>(wanted_range, std::ceil((float)fog_distance / MAP_BLOCKSIZE));
+	}
 	float camera_fov = sao->getFov();
 
 	/*