Another fix for handling invalid format 2 cmaps.

Sigh.

Reported as

  https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=8003

* src/sfnt/ttcmap.c (tt_cmap2_char_next): Adjust condition to avoid
an endless loop.

ChangeLog

@@ -1,3 +1,16 @@
+2018-04-26  Werner Lemberg  <wl@gnu.org>
+
+	Another fix for handling invalid format 2 cmaps.
+
+	Sigh.
+
+	Reported as
+
+	  https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=8003
+
+	* src/sfnt/ttcmap.c (tt_cmap2_char_next): Adjust condition to avoid
+	an endless loop.
+
 2018-04-24  Ben Wagner  <bungeman@google.com>
 
 	[base] Avoid undefined behaviour in lcd filtering code (#53727).

src/sfnt/ttcmap.c

@@ -518,7 +518,7 @@
         FT_UInt   pos, idx;
 
 
-        if ( char_lo > start + count && charcode <= 0xFF )
+        if ( char_lo >= start + count && charcode <= 0xFF )
         {
           /* this happens only for a malformed cmap */
           charcode = 0x100;