[freetype2] master c4a1ef3: [cff] Catch `blend' op in non-variant fonts.

[Werner LEMBERG]

branch: master
commit c4a1ef3c948f261e4402fa48512555279379a683
Author: Werner Lemberg <address@hidden>
Commit: Werner Lemberg <address@hidden>

    [cff] Catch `blend' op in non-variant fonts.
    
    Reported as
    
      https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=334
    
    * src/cff/cf2intrp.c (cf2_interpT2CharString) <cf2_cmdBLEND>: Don't
    allow `blend' op for non-variant fonts.
---
 ChangeLog          |   11 +++++++++++
 src/cff/cf2intrp.c |    7 +++++++
 2 files changed, 18 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index 627b938..1785457 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,16 @@
 2016-12-28  Werner Lemberg  <address@hidden>
 
+       [cff] Catch `blend' op in non-variant fonts.
+
+       Reported as
+
+         https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=334
+
+       * src/cff/cf2intrp.c (cf2_interpT2CharString) <cf2_cmdBLEND>: Don't
+       allow `blend' op for non-variant fonts.
+
+2016-12-28  Werner Lemberg  <address@hidden>
+
        [cff] Better check of number of blends.
 
        * src/cff/cf2intrp.c (cf2_interpT2CharString) <cf2_cmdBLEND>,
diff --git a/src/cff/cf2intrp.c b/src/cff/cf2intrp.c
index ef52999..e4824b0 100644
--- a/src/cff/cf2intrp.c
+++ b/src/cff/cf2intrp.c
@@ -678,6 +678,13 @@
           if ( !font->isCFF2 )
             break;    /* clear stack & ignore */
 
+          /* do we have a `blend' op in a non-variant font? */
+          if ( !font->blend.font )
+          {
+            lastError = FT_THROW( Invalid_Glyph_Format );
+            goto exit;
+          }
+
           /* check cached blend vector */
           if ( cff_blend_check_vector( &font->blend,
                                        font->vsindex,