Avoid crashes rescaling fonts with long names

* src/font.c (font_rescale_ratio): Check NAME is not nil before
matching it against a regexp.

1 files changed, 5 insertions, 1 deletions

diff --git a/src/font.c b/src/font.c
index 7f8ddc4dc34..ff81fefcad0 100644
--- a/src/font.c
+++ b/src/font.c
@@ -1879,7 +1879,11 @@ font_rescale_ratio (Lisp_Object font_entity)
             {
               if (NILP (name))
                 name = Ffont_xlfd_name (font_entity, Qnil);
-              if (fast_string_match_ignore_case (XCAR (elt), name) >= 0)
+
+              /* N.B. that `name' is set to nil if the resulting XLFD
+                 is too long.  */
+              if (!NILP (name)
+                  && fast_string_match_ignore_case (XCAR (elt), name) >= 0)
                 return XFLOAT_DATA (XCDR (elt));
             }
           else if (FONT_SPEC_P (XCAR (elt)))