From c3d23675d1f6d0df2788d52f0ee9cfb2454c2645 Mon Sep 17 00:00:00 2001
From: Eric Fischer <enf@pobox.com>
Date: Thu, 7 Sep 2017 13:48:09 -0700
Subject: [PATCH] Also fix arithmetic overflow when reading a Geobuf
 GeometryCollection

---
 geobuf.cpp | 3 +++
 serial.cpp | 5 ++++-
 2 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/geobuf.cpp b/geobuf.cpp
index d83630fd..05ff8b66 100644
--- a/geobuf.cpp
+++ b/geobuf.cpp
@@ -255,6 +255,9 @@ std::vector<drawvec_type> readGeometry(protozero::pbf_reader &pbf, size_t dim, d
 		dv.dv = readMultiLine(coords, lengths, dim, e, true);
 	} else if (type == MULTIPOLYGON) {
 		dv.dv = readMultiPolygon(coords, lengths, dim, e);
+	} else {
+		// GeometryCollection
+		return ret;
 	}
 
 	dv.type = type / 2 + 1;
diff --git a/serial.cpp b/serial.cpp
index 76b99d20..adb23bcc 100644
--- a/serial.cpp
+++ b/serial.cpp
@@ -425,7 +425,10 @@ int serialize_feature(struct serialization_state *sst, serial_feature &sf) {
 	if (sf.geometry.size() > 0 && (sf.bbox[2] < sf.bbox[0] || sf.bbox[3] < sf.bbox[1])) {
 		fprintf(stderr, "Internal error: impossible feature bounding box %llx,%llx,%llx,%llx\n", sf.bbox[0], sf.bbox[1], sf.bbox[2], sf.bbox[3]);
 	}
-	if (sf.bbox[2] - sf.bbox[0] > (2LL << (32 - sst->maxzoom)) || sf.bbox[3] - sf.bbox[1] > (2LL << (32 - sst->maxzoom))) {
+	if (sf.bbox[0] == LLONG_MAX) {
+		// No bounding box (empty geometry)
+		// Shouldn't happen, but avoid arithmetic overflow below
+	} else if (sf.bbox[2] - sf.bbox[0] > (2LL << (32 - sst->maxzoom)) || sf.bbox[3] - sf.bbox[1] > (2LL << (32 - sst->maxzoom))) {
 		inline_meta = false;
 
 		if (prevent[P_CLIPPING]) {