Another fix for handling invalid format 2 cmaps.

The previous commit was incomplete.

Reported as

  https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=7928

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

ChangeLog

@@ -1,3 +1,16 @@
+2018-04-22  Werner Lemberg  <wl@gnu.org>
+
+	Another fix for handling invalid format 2 cmaps.
+
+	The previous commit was incomplete.
+
+	Reported as
+
+	  https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=7928
+
+	* src/sfnt/ttcmap.c (tt_cmap2_char_next): Adjust condition to avoid
+	an endless loop.
+
 2018-04-19  Werner Lemberg  <wl@gnu.org
 
 	[autofit] Add support for Georgian Mtavruli characters.
@@ -9,7 +22,7 @@
 
 	* src/autofit/afscript.h: Add Mtavruli standard character.
 
-2018-03-13  Werner Lemberg  <wl@gnu.org>
+2018-04-18  Werner Lemberg  <wl@gnu.org>
 
 	Fix handling of invalid format 2 cmaps.
 

src/sfnt/ttcmap.c

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