From 3f090c6843dea837d1054e994e9ba18fefb75a62 Mon Sep 17 00:00:00 2001
From: Werner Lemberg <wl@gnu.org>
Date: Sun, 31 Dec 2017 10:32:08 +0100
Subject: [PATCH] * src/sfnt/ttcmap.c (tt_cmap2_char_next): Fix endless loop.

Reported as

  https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=4838
---
 ChangeLog         | 8 ++++++++
 src/sfnt/ttcmap.c | 4 ++++
 2 files changed, 12 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index 5942a16ce..74351bcd4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2017-12-31  Werner Lemberg  <wl@gnu.org>
+
+	* src/sfnt/ttcmap.c (tt_cmap2_char_next): Fix endless loop.
+
+	Reported as
+
+	  https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=4838
+
 2017-12-31  Werner Lemberg  <wl@gnu.org>
 
 	Synchronize other Windows project files.
diff --git a/src/sfnt/ttcmap.c b/src/sfnt/ttcmap.c
index f6c02f907..45414d1ae 100644
--- a/src/sfnt/ttcmap.c
+++ b/src/sfnt/ttcmap.c
@@ -518,7 +518,11 @@
 
 
         if ( offset == 0 )
+        {
+          if ( charcode == 0x100 )
+            goto Exit; /* this happens only for a malformed cmap */
           goto Next_SubHeader;
+        }
 
         if ( char_lo < start )
         {