Fix find_nodes_in_area misbehaving with out-of-map coordinates (#11770)

This ensures that no overflows (side-effects) happen within the find_nodes_in_area function by limiting coordinates like done in the map generation code.

1 files changed, 17 insertions, 14 deletions

diff --git a/src/script/lua_api/l_env.cpp b/src/script/lua_api/l_env.cpp
index 2c709d31b..18ee3a521 100644
--- a/src/script/lua_api/l_env.cpp
+++ b/src/script/lua_api/l_env.cpp
@@ -880,6 +880,21 @@ int ModApiEnvMod::l_find_node_near(lua_State *L)
 	return 0;
 }
 
+static void checkArea(v3s16 &minp, v3s16 &maxp)
+{
+	auto volume = VoxelArea(minp, maxp).getVolume();
+	// Volume limit equal to 8 default mapchunks, (80 * 2) ^ 3 = 4,096,000
+	if (volume > 4096000) {
+		throw LuaError("Area volume exceeds allowed value of 4096000");
+	}
+
+	// Clamp to map range to avoid problems
+#define CLAMP(arg) core::clamp(arg, (s16)-MAX_MAP_GENERATION_LIMIT, (s16)MAX_MAP_GENERATION_LIMIT)
+	minp = v3s16(CLAMP(minp.X), CLAMP(minp.Y), CLAMP(minp.Z));
+	maxp = v3s16(CLAMP(maxp.X), CLAMP(maxp.Y), CLAMP(maxp.Z));
+#undef CLAMP
+}
+
 // find_nodes_in_area(minp, maxp, nodenames, [grouped])
 int ModApiEnvMod::l_find_nodes_in_area(lua_State *L)
 {
@@ -899,13 +914,7 @@ int ModApiEnvMod::l_find_nodes_in_area(lua_State *L)
 	}
 #endif
 
-	v3s16 cube = maxp - minp + 1;
-	// Volume limit equal to 8 default mapchunks, (80 * 2) ^ 3 = 4,096,000
-	if ((u64)cube.X * (u64)cube.Y * (u64)cube.Z > 4096000) {
-		luaL_error(L, "find_nodes_in_area(): area volume"
-				" exceeds allowed value of 4096000");
-		return 0;
-	}
+	checkArea(minp, maxp);
 
 	std::vector<content_t> filter;
 	collectNodeIds(L, 3, ndef, filter);
@@ -1010,13 +1019,7 @@ int ModApiEnvMod::l_find_nodes_in_area_under_air(lua_State *L)
 	}
 #endif
 
-	v3s16 cube = maxp - minp + 1;
-	// Volume limit equal to 8 default mapchunks, (80 * 2) ^ 3 = 4,096,000
-	if ((u64)cube.X * (u64)cube.Y * (u64)cube.Z > 4096000) {
-		luaL_error(L, "find_nodes_in_area_under_air(): area volume"
-				" exceeds allowed value of 4096000");
-		return 0;
-	}
+	checkArea(minp, maxp);
 
 	std::vector<content_t> filter;
 	collectNodeIds(L, 3, ndef, filter);