From 06c2d3324e8a8dbe153d51129adadd8d8eb4f834 Mon Sep 17 00:00:00 2001
From: Werner Lemberg <wl@gnu.org>
Date: Thu, 8 Oct 2015 21:31:57 +0200
Subject: [PATCH] [type42] Protect against invalid number of glyphs (#46159).

* src/type42/t42parse.c (t42_parse_charstrings): Check number of
`CharStrings' dictionary entries against size of data stream.
---
 ChangeLog             |  7 +++++++
 src/type42/t42parse.c | 11 +++++++++++
 2 files changed, 18 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index 066136a5e..f4e30c679 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2015-10-08  Werner Lemberg  <wl@gnu.org>
+
+	[type42] Protect against invalid number of glyphs (#46159).
+
+	* src/type42/t42parse.c (t42_parse_charstrings): Check number of
+	`CharStrings' dictionary entries against size of data stream.
+
 2015-10-08  Werner Lemberg  <wl@gnu.org>
 
 	[sfnt] Fix some signed overflows (#46149).
diff --git a/src/type42/t42parse.c b/src/type42/t42parse.c
index 003b63ed7..a32d496af 100644
--- a/src/type42/t42parse.c
+++ b/src/type42/t42parse.c
@@ -795,6 +795,17 @@
         error = FT_THROW( Invalid_File_Format );
         goto Fail;
       }
+
+      /* we certainly need more than 4 bytes per glyph */
+      if ( loader->num_glyphs > ( limit - parser->root.cursor ) >> 2 )
+      {
+        FT_TRACE0(( "t42_parse_charstrings: adjusting number of glyphs"
+                    " (from %d to %d)\n",
+                    loader->num_glyphs,
+                    ( limit - parser->root.cursor ) >> 2 ));
+        loader->num_glyphs = ( limit - parser->root.cursor ) >> 2;
+      }
+
     }
     else if ( *parser->root.cursor == '<' )
     {