From f16a865420eb8ea00defc6fa145b9015bfdec621 Mon Sep 17 00:00:00 2001
From: "Daniel J. Hofmann" <daniel@trvx.org>
Date: Fri, 18 Mar 2016 15:30:28 +0100
Subject: [PATCH] Make Tile plugin validate its parameters, fixes #2109

---
 include/engine/api/tile_parameters.hpp | 14 ++++++++++++--
 src/engine/plugins/tile.cpp            |  2 ++
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/include/engine/api/tile_parameters.hpp b/include/engine/api/tile_parameters.hpp
index 937b8a50f..261264c03 100644
--- a/include/engine/api/tile_parameters.hpp
+++ b/include/engine/api/tile_parameters.hpp
@@ -28,6 +28,8 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifndef ENGINE_API_TILE_PARAMETERS_HPP
 #define ENGINE_API_TILE_PARAMETERS_HPP
 
+#include <cmath>
+
 namespace osrm
 {
 namespace engine
@@ -41,8 +43,16 @@ struct TileParameters final
     unsigned y;
     unsigned z;
 
-    // FIXME check if x and y work with z
-    bool IsValid() { return z < 20; };
+    bool IsValid() const
+    {
+        // https://wiki.openstreetmap.org/wiki/Slippy_map_tilenames#Zoom_levels
+        // https://wiki.openstreetmap.org/wiki/Slippy_map_tilenames#X_and_Y
+        const auto valid_x = x <= static_cast<unsigned>(std::pow(2., z)) - 1;
+        const auto valid_y = y <= static_cast<unsigned>(std::pow(2., z)) - 1;
+        const auto valid_z = z < 20;
+
+        return valid_x && valid_y && valid_z;
+    };
 };
 }
 }
diff --git a/src/engine/plugins/tile.cpp b/src/engine/plugins/tile.cpp
index 5eae0b465..f33a711d1 100644
--- a/src/engine/plugins/tile.cpp
+++ b/src/engine/plugins/tile.cpp
@@ -168,6 +168,8 @@ FixedLine coordinatesToTileLine(const util::Coordinate start,
 
 Status TilePlugin::HandleRequest(const api::TileParameters &parameters, std::string &pbf_buffer)
 {
+    BOOST_ASSERT(parameters.IsValid());
+
     using namespace util::coordinate_calculation;
     double min_lon, min_lat, max_lon, max_lat;