From 45c2b6e384e3359a54f40e4b02df9fffe27b0def Mon Sep 17 00:00:00 2001
From: Behdad Esfahbod <behdad@behdad.org>
Date: Sun, 2 Jan 2022 10:55:11 -0700
Subject: [PATCH] [metrics] Harden math

---
 src/hb-ot-metrics.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/hb-ot-metrics.cc b/src/hb-ot-metrics.cc
index 743a7f687..f0c437a3c 100644
--- a/src/hb-ot-metrics.cc
+++ b/src/hb-ot-metrics.cc
@@ -166,7 +166,7 @@ hb_ot_metrics_get_position (hb_font_t           *font,
   {
     unsigned rise = face->table.hhea->caretSlopeRise;
     unsigned upem = face->get_upem ();
-    unsigned mult = rise < upem ? upem / rise : 1;
+    unsigned mult = (rise && rise < upem) ? hb_min (upem / rise, 256u) : 1u;
 
     if (metrics_tag == HB_OT_METRICS_TAG_HORIZONTAL_CARET_RISE)
       return mult * GET_METRIC_Y (hhea, caretSlopeRise);