[freetype2] master e1f364e 64/68: [woff2] Fix memory leak.

[Werner Lemberg]

branch: master
commit e1f364e5097008c845f1963f938b6e8adab5e4e6
Author: Werner Lemberg <wl@gnu.org>
Commit: Werner Lemberg <wl@gnu.org>

    [woff2] Fix memory leak.
    
    Reported as
    
      https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=28148
    
    * src/sfnt/sfwoff2.c (woff2_open_font): Reject fonts that have
    multiple tables with the same tag.  While not explicitly forbidden
    in the OpenType specification, it is implicitly forbidden by
    describing a binary search algorithm for tables that only works
    reliably if table tags are unique.
---
 ChangeLog          | 14 ++++++++++++++
 src/sfnt/sfwoff2.c | 19 +++++++++++++++++++
 2 files changed, 33 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index 59919e7..7945b1e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,17 @@
+2021-02-25  Werner Lemberg  <wl@gnu.org>
+
+       [woff2] Fix memory leak.
+
+       Reported as
+
+         https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=28148
+
+       * src/sfnt/sfwoff2.c (woff2_open_font): Reject fonts that have
+       multiple tables with the same tag.  While not explicitly forbidden
+       in the OpenType specification, it is implicitly forbidden by
+       describing a binary search algorithm for tables that only works
+       reliably if table tags are unique.
+
 2021-02-22  Werner Lemberg  <wl@gnu.org>
 
        * CMakeLists.txt: Update location of `LICENSE.TXT`.
diff --git a/src/sfnt/sfwoff2.c b/src/sfnt/sfwoff2.c
index 2fe7f47..edf173d 100644
--- a/src/sfnt/sfwoff2.c
+++ b/src/sfnt/sfwoff2.c
@@ -2208,6 +2208,25 @@
               sizeof ( WOFF2_Table ),
               compare_tags );
 
+    /* reject fonts that have multiple tables with the same tag */
+    for ( nn = 1; nn < woff2.num_tables; nn++ )
+    {
+      FT_ULong  tag = indices[nn]->Tag;
+
+
+      if ( tag == indices[nn - 1]->Tag )
+      {
+        FT_ERROR(( "woff2_open_font:"
+                   " multiple tables with tag `%c%c%c%c'.\n",
+                   (FT_Char)( tag >> 24 ),
+                   (FT_Char)( tag >> 16 ),
+                   (FT_Char)( tag >> 8  ),
+                   (FT_Char)( tag       ) ));
+        error = FT_THROW( Invalid_Table );
+        goto Exit;
+      }
+    }
+
     if ( woff2.uncompressed_size < 1 )
     {
       error = FT_THROW( Invalid_Table );