reverse_proxy: Add support for NTLM

This commit is contained in:
Matthew Holt 2019-11-05 16:29:10 -07:00
parent 6e95477224
commit 8e515289cb
No known key found for this signature in database
GPG key ID: 2A349DD577D586A5
3 changed files with 272 additions and 26 deletions

View file

@ -35,15 +35,15 @@ func init() {
// HTTPTransport is essentially a configuration wrapper for http.Transport.
// It defines a JSON structure useful when configuring the HTTP transport
// for Caddy's reverse proxy.
// for Caddy's reverse proxy. It builds its http.Transport at Provision.
type HTTPTransport struct {
// TODO: It's possible that other transports (like fastcgi) might be
// able to borrow/use at least some of these config fields; if so,
// move them into a type called CommonTransport and embed it
// maybe move them into a type called CommonTransport and embed it?
TLS *TLSConfig `json:"tls,omitempty"`
KeepAlive *KeepAlive `json:"keep_alive,omitempty"`
Compression *bool `json:"compression,omitempty"`
MaxConnsPerHost int `json:"max_conns_per_host,omitempty"` // TODO: NOTE: we use our health check stuff to enforce max REQUESTS per host, but this is connections
MaxConnsPerHost int `json:"max_conns_per_host,omitempty"`
DialTimeout caddy.Duration `json:"dial_timeout,omitempty"`
FallbackDelay caddy.Duration `json:"dial_fallback_delay,omitempty"`
ResponseHeaderTimeout caddy.Duration `json:"response_header_timeout,omitempty"`
@ -53,7 +53,7 @@ type HTTPTransport struct {
ReadBufferSize int `json:"read_buffer_size,omitempty"`
Versions []string `json:"versions,omitempty"`
RoundTripper http.RoundTripper `json:"-"`
Transport *http.Transport `json:"-"`
}
// CaddyModule returns the Caddy module information.
@ -64,12 +64,23 @@ func (HTTPTransport) CaddyModule() caddy.ModuleInfo {
}
}
// Provision sets up h.RoundTripper with a http.Transport
// Provision sets up h.Transport with a *http.Transport
// that is ready to use.
func (h *HTTPTransport) Provision(_ caddy.Context) error {
if len(h.Versions) == 0 {
h.Versions = []string{"1.1", "2"}
}
rt, err := h.newTransport()
if err != nil {
return err
}
h.Transport = rt
return nil
}
func (h *HTTPTransport) newTransport() (*http.Transport, error) {
dialer := &net.Dialer{
Timeout: time.Duration(h.DialTimeout),
FallbackDelay: time.Duration(h.FallbackDelay),
@ -107,14 +118,14 @@ func (h *HTTPTransport) Provision(_ caddy.Context) error {
var err error
rt.TLSClientConfig, err = h.TLS.MakeTLSClientConfig()
if err != nil {
return fmt.Errorf("making TLS client config: %v", err)
return nil, fmt.Errorf("making TLS client config: %v", err)
}
}
if h.KeepAlive != nil {
dialer.KeepAlive = time.Duration(h.KeepAlive.ProbeInterval)
if enabled := h.KeepAlive.Enabled; enabled != nil {
rt.DisableKeepAlives = !*enabled
if h.KeepAlive.Enabled != nil {
rt.DisableKeepAlives = !*h.KeepAlive.Enabled
}
rt.MaxIdleConns = h.KeepAlive.MaxIdleConns
rt.MaxIdleConnsPerHost = h.KeepAlive.MaxIdleConnsPerHost
@ -131,21 +142,30 @@ func (h *HTTPTransport) Provision(_ caddy.Context) error {
}
}
h.RoundTripper = rt
return nil
return rt, nil
}
// RoundTrip implements http.RoundTripper with h.RoundTripper.
func (h HTTPTransport) RoundTrip(req *http.Request) (*http.Response, error) {
return h.RoundTripper.RoundTrip(req)
// RoundTrip implements http.RoundTripper.
func (h *HTTPTransport) RoundTrip(req *http.Request) (*http.Response, error) {
h.setScheme(req)
return h.Transport.RoundTrip(req)
}
// setScheme ensures that the outbound request req
// has the scheme set in its URL; the underlying
// http.Transport requires a scheme to be set.
func (h *HTTPTransport) setScheme(req *http.Request) {
if req.URL.Scheme == "" {
req.URL.Scheme = "http"
if h.TLS != nil {
req.URL.Scheme = "https"
}
}
}
// Cleanup implements caddy.CleanerUpper and closes any idle connections.
func (h HTTPTransport) Cleanup() error {
if ht, ok := h.RoundTripper.(*http.Transport); ok {
ht.CloseIdleConnections()
}
h.Transport.CloseIdleConnections()
return nil
}

View file

@ -0,0 +1,234 @@
// Copyright 2015 Matthew Holt and The Caddy Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package reverseproxy
import (
"context"
"fmt"
"net"
"net/http"
"sync"
"github.com/caddyserver/caddy/v2"
"github.com/caddyserver/caddy/v2/modules/caddyhttp"
)
func init() {
caddy.RegisterModule(NTLMTransport{})
}
// NTLMTransport proxies HTTP+NTLM authentication is being used.
// It basically wraps HTTPTransport so that it is compatible with
// NTLM's HTTP-hostile requirements. Specifically, it will use
// HTTPTransport's single, default *http.Transport for all requests
// (unless the client's connection is already mapped to a different
// transport) until a request comes in with Authorization header
// that has "NTLM" or "Negotiate"; when that happens, NTLMTransport
// maps the client's connection (by its address, req.RemoteAddr)
// to a new transport that is used only by that downstream conn.
// When the upstream connection is closed, the mapping is deleted.
// This preserves NTLM authentication contexts by ensuring that
// client connections use the same upstream connection. It does
// hurt performance a bit, but that's NTLM for you.
//
// This transport also forces HTTP/1.1 and Keep-Alives in order
// for NTLM to succeed.
type NTLMTransport struct {
*HTTPTransport
transports map[string]*http.Transport
transportsMu *sync.RWMutex
}
// CaddyModule returns the Caddy module information.
func (NTLMTransport) CaddyModule() caddy.ModuleInfo {
return caddy.ModuleInfo{
Name: "http.handlers.reverse_proxy.transport.http_ntlm",
New: func() caddy.Module { return new(NTLMTransport) },
}
}
// Provision sets up the transport module.
func (n *NTLMTransport) Provision(ctx caddy.Context) error {
n.transports = make(map[string]*http.Transport)
n.transportsMu = new(sync.RWMutex)
if n.HTTPTransport == nil {
n.HTTPTransport = new(HTTPTransport)
}
// NTLM requires HTTP/1.1
n.HTTPTransport.Versions = []string{"1.1"}
// NLTM requires keep-alive
if n.HTTPTransport.KeepAlive != nil {
enabled := true
n.HTTPTransport.KeepAlive.Enabled = &enabled
}
// set up the underlying transport, since we
// rely on it for the heavy lifting
err := n.HTTPTransport.Provision(ctx)
if err != nil {
return err
}
return nil
}
// RoundTrip implements http.RoundTripper. It basically wraps
// the underlying HTTPTransport.Transport in a way that preserves
// NTLM context by mapping transports/connections. Note that this
// method does not call n.HTTPTransport.RoundTrip (our own method),
// but the underlying n.HTTPTransport.Transport.RoundTrip (standard
// library's method).
func (n *NTLMTransport) RoundTrip(req *http.Request) (*http.Response, error) {
n.HTTPTransport.setScheme(req)
// when the upstream connection is closed, make sure
// we close the downstream connection with the client
// when this request is done; we only do this if
// using a bound transport
closeDownstreamIfClosedUpstream := func() {
n.transportsMu.Lock()
if _, ok := n.transports[req.RemoteAddr]; !ok {
req.Close = true
}
n.transportsMu.Unlock()
}
// first, see if this downstream connection is
// already bound to a particular transport
// (transports are abstractions over connections
// to our upstream, and NTLM auth requires
// preserving authentication state for separate
// connections over multiple roundtrips, sigh)
n.transportsMu.Lock()
transport, ok := n.transports[req.RemoteAddr]
if ok {
n.transportsMu.Unlock()
defer closeDownstreamIfClosedUpstream()
return transport.RoundTrip(req)
}
// otherwise, start by assuming we will use
// the default transport that carries all
// normal/non-NTLM-authenticated requests
transport = n.HTTPTransport.Transport
// but if this request begins the NTLM authentication
// process, we need to pin it to a specific transport
if requestHasAuth(req) {
var err error
transport, err = n.newTransport()
if err != nil {
return nil, fmt.Errorf("making new transport for %s: %v", req.RemoteAddr, err)
}
n.transports[req.RemoteAddr] = transport
defer closeDownstreamIfClosedUpstream()
}
n.transportsMu.Unlock()
// finally, do the roundtrip with the transport we selected
return transport.RoundTrip(req)
}
// newTransport makes an NTLM-compatible transport.
func (n *NTLMTransport) newTransport() (*http.Transport, error) {
// start with a regular HTTP transport
transport, err := n.HTTPTransport.newTransport()
if err != nil {
return nil, err
}
// we need to wrap upstream connections so we can
// clean up in two ways when that connection is
// closed: 1) destroy the transport that housed
// this connection, and 2) use that as a signal
// to close the connection to the downstream.
wrappedDialContext := transport.DialContext
transport.DialContext = func(ctx context.Context, network, address string) (net.Conn, error) {
conn2, err := wrappedDialContext(ctx, network, address)
if err != nil {
return nil, err
}
req := ctx.Value(caddyhttp.OriginalRequestCtxKey).(http.Request)
conn := &unbinderConn{Conn: conn2, ntlm: n, clientAddr: req.RemoteAddr}
return conn, nil
}
return transport, nil
}
// Cleanup implements caddy.CleanerUpper and closes any idle connections.
func (n *NTLMTransport) Cleanup() error {
if err := n.HTTPTransport.Cleanup(); err != nil {
return err
}
n.transportsMu.Lock()
for _, t := range n.transports {
t.CloseIdleConnections()
}
n.transports = make(map[string]*http.Transport)
n.transportsMu.Unlock()
return nil
}
// deleteTransportsForClient deletes (unmaps) transports that are
// associated with clientAddr (a req.RemoteAddr value).
func (n *NTLMTransport) deleteTransportsForClient(clientAddr string) {
n.transportsMu.Lock()
for key := range n.transports {
if key == clientAddr {
delete(n.transports, key)
}
}
n.transportsMu.Unlock()
}
// requestHasAuth returns true if req has an Authorization
// header with values "NTLM" or "Negotiate".
func requestHasAuth(req *http.Request) bool {
for _, val := range req.Header["Authorization"] {
if val == "NTLM" || val == "Negotiate" {
return true
}
}
return false
}
// unbinderConn is used to wrap upstream connections
// so that we know when they are closed and can clean
// up after that.
type unbinderConn struct {
net.Conn
clientAddr string
ntlm *NTLMTransport
}
func (uc *unbinderConn) Close() error {
uc.ntlm.deleteTransportsForClient(uc.clientAddr)
return uc.Conn.Close()
}
// Interface guards
var (
_ caddy.Provisioner = (*NTLMTransport)(nil)
_ http.RoundTripper = (*NTLMTransport)(nil)
_ caddy.CleanerUpper = (*NTLMTransport)(nil)
)

View file

@ -311,15 +311,7 @@ func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyht
// This assumes that no mutations of the request are performed
// by h during or after proxying.
func (h Handler) prepareRequest(req *http.Request) error {
// as a special (but very common) case, if the transport
// is HTTP, then ensure the request has the proper scheme
// because incoming requests by default are lacking it
if req.URL.Scheme == "" {
req.URL.Scheme = "http"
if ht, ok := h.Transport.(*HTTPTransport); ok && ht.TLS != nil {
req.URL.Scheme = "https"
}
}
// most of this is borrowed from the Go std lib reverse proxy
if req.ContentLength == 0 {
req.Body = nil // Issue golang/go#16036: nil Body for http.Transport retries