read_mp4_tag_string() may return a NULL in the pointer so no code should rely

on the pointer being valid unless the return code is checked. This lead to the
year_string being accessed with atoi() even when being NULL => crash. This
fixes FS#7937.


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@15080 a1c6a512-1295-4272-9138-f99709370657

apps/metadata/mp4.c

@@ -406,12 +406,16 @@ static bool read_mp4_tags(int fd, struct mp3entry* id3,
  
             /* Try to parse it as a year, for the benefit of the database.
              */
+            if(id3->year_string)
+            {
                 id3->year = atoi(id3->year_string);
-
                 if (id3->year < 1900)
                 {
                     id3->year = 0;
                 }
+            }
+            else
+                id3->year = 0;
 
             break;