* src/sfnt/sfdriver.c (sfnt_get_var_ps_name): Check `result'.

Reported as

  https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=10316
diff --git a/ChangeLog b/ChangeLog
index 3fc08c9..8436079 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2018-09-13  Werner Lemberg  <wl@gnu.org>
+
+	* src/sfnt/sfdriver.c (sfnt_get_var_ps_name): Check `result'.
+
+	Reported as
+
+	  https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=10316
+
 2018-09-12  John Tytgat  <John.Tytgat@esko.com>
 
 	[sfnt] Better PS name handling (#54629).
diff --git a/src/sfnt/sfdriver.c b/src/sfnt/sfdriver.c
index 149c9c5..b7e4358 100644
--- a/src/sfnt/sfdriver.c
+++ b/src/sfnt/sfdriver.c
@@ -841,7 +841,7 @@
                                    sfnt_is_alphanumeric,
                                    0 );
 
-      len = ft_strlen( result );
+      len = result ? ft_strlen( result ) : 0;
 
       /* sanitize if necessary; we reserve space for 36 bytes (a 128bit  */
       /* checksum as a hex number, preceded by `-' and followed by three */