#1554 check adminFilter length before LDAP search

modules/auth/ldap/ldap.go

@@ -120,13 +120,14 @@ func (ls Ldapsource) SearchEntry(name, passwd string) (string, string, string, b
 	sn_attr := sr.Entries[0].GetAttributeValue(ls.AttributeSurname)
 	mail_attr := sr.Entries[0].GetAttributeValue(ls.AttributeMail)
 
+	admin_attr := false
+	if len(ls.AdminFilter) > 0 {
 		search = ldap.NewSearchRequest(
 			userDN, ldap.ScopeWholeSubtree, ldap.NeverDerefAliases, 0, 0, false, ls.AdminFilter,
 			[]string{ls.AttributeName},
 			nil)
 
 		sr, err = l.Search(search)
-	admin_attr := false
 		if err != nil {
 			log.Error(4, "LDAP Admin Search failed unexpectedly! (%v)", err)
 		} else if len(sr.Entries) < 1 {
@@ -134,6 +135,7 @@ func (ls Ldapsource) SearchEntry(name, passwd string) (string, string, string, b
 		} else {
 			admin_attr = true
 		}
+	}
 
 	return name_attr, sn_attr, mail_attr, admin_attr, true
 }