From 937ccd17ac65935633b2ebc06cb7089b91e17e6b Mon Sep 17 00:00:00 2001
From: Chris Liddell <chris.liddell@artifex.com>
Date: Thu, 15 Jun 2017 09:05:20 +0100
Subject: [PATCH] Bug 698056: make bounds check in gx_ttfReader__Read more
 robust

---
 base/gxttfb.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/base/gxttfb.c b/base/gxttfb.c
index 0e9a444..e1561af 100644
--- a/base/gxttfb.c
+++ b/base/gxttfb.c
@@ -79,7 +79,8 @@ static void gx_ttfReader__Read(ttfReader *self, void *p, int n)
     if (!r->error) {
         if (r->extra_glyph_index != -1) {
             q = r->glyph_data.bits.data + r->pos;
-            r->error = (r->glyph_data.bits.size - r->pos < n ?
+            r->error = ((r->pos >= r->glyph_data.bits.size ||
+                        r->glyph_data.bits.size - r->pos < n) ?
                             gs_note_error(gs_error_invalidfont) : 0);
             if (r->error == 0)
                 memcpy(p, q, n);
-- 
2.9.1