[freetype2] master 4d364b6: [woff2] Fix segfault.

[Werner LEMBERG]

branch: master
commit 4d364b68215f1380b66164f3f0e4bdadc154d08f
Author: Werner Lemberg <wl@gnu.org>
Commit: Werner Lemberg <wl@gnu.org>

    [woff2] Fix segfault.
    
    Reported as
    
      https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=23402
    
    * src/sfnt/sfwoff2.c (get_x_mins): Check whether `loca' table
    exists.
---
 ChangeLog          | 11 +++++++++++
 src/sfnt/sfwoff2.c |  6 ++++++
 2 files changed, 17 insertions(+)

diff --git a/ChangeLog b/ChangeLog
index afe932d..950c19c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,14 @@
+2020-06-19  Werner Lemberg  <wl@gnu.org>
+
+       [woff2] Fix segfault.
+
+       Reported as
+
+         https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=23402
+
+       * src/sfnt/sfwoff2.c (get_x_mins): Check whether `loca' table
+       exists.
+
 2020-06-19  Stephen McDowell  <svenevs.dev@gmail.com>
 
        [sfnt] Support Intel compilers.
diff --git a/src/sfnt/sfwoff2.c b/src/sfnt/sfwoff2.c
index 3f59044..781b932 100644
--- a/src/sfnt/sfwoff2.c
+++ b/src/sfnt/sfwoff2.c
@@ -1286,6 +1286,12 @@
       return FT_THROW( Invalid_Table );
     }
 
+    if ( !info->loca_table )
+    {
+      FT_ERROR(( "`loca' table is missing.\n" ));
+      return FT_THROW( Invalid_Table );
+    }
+
     /* Read `numGlyphs' field from `maxp' table. */
     if ( FT_STREAM_SEEK( maxp_table->src_offset ) || FT_STREAM_SKIP( 8 ) )
       return error;