Method enforcementHandler

modules/caddyhttp/server.go:524–543

enforcementHandler is an implicit middleware which performs standard checks before executing the HTTP middleware chain.

(w http.ResponseWriter, r *http.Request, next Handler)

// enforcementHandler is an implicit middleware which performs
// standard checks before executing the HTTP middleware chain.
func (s *Server) enforcementHandler(w http.ResponseWriter, r *http.Request, next Handler) error {
	// enforce strict host matching, which ensures that the SNI
	// value (if any), matches the Host header; essential for
	// servers that rely on TLS ClientAuth sharing a listener
	// with servers that do not; if not enforced, client could
	// bypass by sending benign SNI then restricted Host header
	if s.StrictSNIHost != nil && *s.StrictSNIHost && r.TLS != nil {
		hostname, _, err := net.SplitHostPort(r.Host)
		if err != nil {
			hostname = r.Host // OK; probably lacked port
		}
		if !strings.EqualFold(r.TLS.ServerName, hostname) {
			err := fmt.Errorf("strict host matching: TLS ServerName (%s) and HTTP Host (%s) values differ",
				r.TLS.ServerName, hostname)
			r.Close = true
			return Error(http.StatusMisdirectedRequest, err)
		}
	}
	return next.ServeHTTP(w, r)
}

// listenersUseAnyPortOtherThan returns true if there are any
// listeners in s that use a port which is not otherPort.