[freetype2] master b75031a: * src/sfnt/sfwoff2.c (woff2_open_font): Check `num_fonts' for TTCs.

[Werner LEMBERG]

branch: master
commit b75031a26eed8838222ddb3a81bc1672a0e463a8
Author: Werner Lemberg <address@hidden>
Commit: Werner Lemberg <address@hidden>

    * src/sfnt/sfwoff2.c (woff2_open_font): Check `num_fonts' for TTCs.
    
    Reported as
    
      https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=18494
---
 ChangeLog          | 8 ++++++++
 src/sfnt/sfwoff2.c | 6 ++++++
 2 files changed, 14 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index cf5e219..72f377c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2019-10-25  Werner Lemberg  <address@hidden>
+
+       * src/sfnt/sfwoff2.c (woff2_open_font): Check `num_fonts' for TTCs.
+
+       Reported as
+
+         https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=18494
+
 2019-10-22  Werner Lemberg  <address@hidden>
 
        * src/sfnt/sfwoff2.c (woff2_open_font): Avoid undefined shift.
diff --git a/src/sfnt/sfwoff2.c b/src/sfnt/sfwoff2.c
index 6896dc9..3134ccd 100644
--- a/src/sfnt/sfwoff2.c
+++ b/src/sfnt/sfwoff2.c
@@ -1948,6 +1948,12 @@
       if ( READ_255USHORT( woff2.num_fonts ) )
         goto Exit;
 
+      if ( !woff2.num_fonts )
+      {
+        error = FT_THROW( Invalid_Table );
+        goto Exit;
+      }
+
       FT_TRACE4(( "Number of fonts in TTC: %ld\n", woff2.num_fonts ));
 
       if ( FT_NEW_ARRAY( woff2.ttc_fonts, woff2.num_fonts ) )