Allow to be run without middleware + improve request reading consistency

Prior to this change, the request URI was only ever read from the
X-Forwarded-Uri header which was only set when the container was
accessed via the forwardauth middleware. As such, it was necessary
to apply the treafik-forward-auth middleware to the treafik-forward-auth
container when running auth host mode.
This is a quirk, unecessary complexity and is a frequent source of
configuration issues.

README.md

@@ -423,8 +423,6 @@ spec:
       - name: traefik-forward-auth
 ```
 
-Note: If using auth host mode, you must apply the middleware to your auth host ingress.
-
 See the examples directory for more examples.
 
 #### Selective Container Authentication in Swarm
@@ -439,8 +437,6 @@ whoami:
     - "traefik.http.routers.whoami.middlewares=traefik-forward-auth"
 ```
 
-Note: If using auth host mode, you must apply the middleware to the traefik-forward-auth container.
-
 See the examples directory for more examples.
 
 #### Rules Based Authentication

examples/traefik-v2/kubernetes/advanced-separate-pod/traefik-forward-auth/ingress.yaml

@@ -16,7 +16,5 @@ spec:
     services:
     - name: traefik-forward-auth
       port: 4181
-    middlewares:
-      - name: traefik-forward-auth
   tls:
     certresolver: default

internal/auth.go

@@ -125,24 +125,19 @@ func ValidateDomains(email string, domains CommaSeparatedList) bool {
 
 // Get the redirect base
 func redirectBase(r *http.Request) string {
-	proto := r.Header.Get("X-Forwarded-Proto")
-	host := r.Header.Get("X-Forwarded-Host")
-
-	return fmt.Sprintf("%s://%s", proto, host)
+	return fmt.Sprintf("%s://%s", r.Header.Get("X-Forwarded-Proto"), r.Host)
 }
 
 // Return url
 func returnUrl(r *http.Request) string {
-	path := r.Header.Get("X-Forwarded-Uri")
-
-	return fmt.Sprintf("%s%s", redirectBase(r), path)
+	return fmt.Sprintf("%s%s", redirectBase(r), r.URL.Path)
 }
 
 // Get oauth redirect uri
 func redirectUri(r *http.Request) string {
 	if use, _ := useAuthDomain(r); use {
-		proto := r.Header.Get("X-Forwarded-Proto")
-		return fmt.Sprintf("%s://%s%s", proto, config.AuthHost, config.Path)
+		p := r.Header.Get("X-Forwarded-Proto")
+		return fmt.Sprintf("%s://%s%s", p, config.AuthHost, config.Path)
 	}
 
 	return fmt.Sprintf("%s%s", redirectBase(r), config.Path)
@@ -155,7 +150,7 @@ func useAuthDomain(r *http.Request) (bool, string) {
 	}
 
 	// Does the request match a given cookie domain?
-	reqMatch, reqHost := matchCookieDomains(r.Header.Get("X-Forwarded-Host"))
+	reqMatch, reqHost := matchCookieDomains(r.Host)
 
 	// Do any of the auth hosts match a cookie domain?
 	authMatch, authHost := matchCookieDomains(config.AuthHost)
@@ -284,10 +279,8 @@ func Nonce() (error, string) {
 
 // Cookie domain
 func cookieDomain(r *http.Request) string {
-	host := r.Header.Get("X-Forwarded-Host")
-
 	// Check if any of the given cookie domains matches
-	_, domain := matchCookieDomains(host)
+	_, domain := matchCookieDomains(r.Host)
 	return domain
 }
 
@@ -297,7 +290,7 @@ func csrfCookieDomain(r *http.Request) string {
 	if use, domain := useAuthDomain(r); use {
 		host = domain
 	} else {
-		host = r.Header.Get("X-Forwarded-Host")
+		host = r.Host
 	}
 
 	// Remove port

internal/auth_test.go

@@ -2,6 +2,7 @@ package tfa
 
 import (
 	"net/http"
+	"net/http/httptest"
 	"net/url"
 	"strings"
 	"testing"
@@ -196,10 +197,8 @@ func TestAuthValidateEmail(t *testing.T) {
 func TestRedirectUri(t *testing.T) {
 	assert := assert.New(t)
 
-	r, _ := http.NewRequest("GET", "http://example.com", nil)
+	r := httptest.NewRequest("GET", "http://app.example.com/hello", nil)
 	r.Header.Add("X-Forwarded-Proto", "http")
-	r.Header.Add("X-Forwarded-Host", "app.example.com")
-	r.Header.Add("X-Forwarded-Uri", "/hello")
 
 	//
 	// No Auth Host
@@ -241,10 +240,8 @@ func TestRedirectUri(t *testing.T) {
 	// With Auth URL + cookie domain, but from different domain
 	// - will not use auth host
 	//
-	r, _ = http.NewRequest("GET", "http://another.com", nil)
+	r = httptest.NewRequest("GET", "https://another.com/hello", nil)
 	r.Header.Add("X-Forwarded-Proto", "https")
-	r.Header.Add("X-Forwarded-Host", "another.com")
-	r.Header.Add("X-Forwarded-Uri", "/hello")
 
 	config.AuthHost = "auth.example.com"
 	config.CookieDomains = []CookieDomain{*NewCookieDomain("example.com")}
@@ -378,10 +375,8 @@ func TestValidateState(t *testing.T) {
 func TestMakeState(t *testing.T) {
 	assert := assert.New(t)
 
-	r, _ := http.NewRequest("GET", "http://example.com", nil)
+	r := httptest.NewRequest("GET", "http://example.com/hello", nil)
 	r.Header.Add("X-Forwarded-Proto", "http")
-	r.Header.Add("X-Forwarded-Host", "example.com")
-	r.Header.Add("X-Forwarded-Uri", "/hello")
 
 	// Test with google
 	p := provider.Google{}

internal/server.go

@@ -58,7 +58,11 @@ func (s *Server) RootHandler(w http.ResponseWriter, r *http.Request) {
 	// Modify request
 	r.Method = r.Header.Get("X-Forwarded-Method")
 	r.Host = r.Header.Get("X-Forwarded-Host")
-	r.URL, _ = url.Parse(r.Header.Get("X-Forwarded-Uri"))
+
+	// Read URI from header if we're acting as forward auth middleware
+	if _, ok := r.Header["X-Forwarded-Uri"]; ok {
+		r.URL, _ = url.Parse(r.Header.Get("X-Forwarded-Uri"))
+	}
 
 	// Pass to mux
 	s.router.ServeHTTP(w, r)

internal/server_test.go

@@ -31,6 +31,37 @@ func init() {
  * Tests
  */
 
+func TestServerRootHandler(t *testing.T) {
+	assert := assert.New(t)
+	config = newDefaultConfig()
+
+	// X-Forwarded headers should be read into request
+	req := httptest.NewRequest("POST", "http://should-use-x-forwarded.com/should?ignore=me", nil)
+	req.Header.Add("X-Forwarded-Method", "GET")
+	req.Header.Add("X-Forwarded-Proto", "https")
+	req.Header.Add("X-Forwarded-Host", "example.com")
+	req.Header.Add("X-Forwarded-Uri", "/foo?q=bar")
+	NewServer().RootHandler(httptest.NewRecorder(), req)
+
+	assert.Equal("GET", req.Method, "x-forwarded-method should be read into request")
+	assert.Equal("example.com", req.Host, "x-forwarded-host should be read into request")
+	assert.Equal("/foo", req.URL.Path, "x-forwarded-uri should be read into request")
+	assert.Equal("/foo?q=bar", req.URL.RequestURI(), "x-forwarded-uri should be read into request")
+
+	// Other X-Forwarded headers should be read in into request and original URL
+	// should be preserved if X-Forwarded-Uri not present
+	req = httptest.NewRequest("POST", "http://should-use-x-forwarded.com/should-not?ignore=me", nil)
+	req.Header.Add("X-Forwarded-Method", "GET")
+	req.Header.Add("X-Forwarded-Proto", "https")
+	req.Header.Add("X-Forwarded-Host", "example.com")
+	NewServer().RootHandler(httptest.NewRecorder(), req)
+
+	assert.Equal("GET", req.Method, "x-forwarded-method should be read into request")
+	assert.Equal("example.com", req.Host, "x-forwarded-host should be read into request")
+	assert.Equal("/should-not", req.URL.Path, "request url should be preserved if x-forwarded-uri not present")
+	assert.Equal("/should-not?ignore=me", req.URL.RequestURI(), "request url should be preserved if x-forwarded-uri not present")
+}
+
 func TestServerAuthHandlerInvalid(t *testing.T) {
 	assert := assert.New(t)
 	config = newDefaultConfig()
@@ -90,10 +121,10 @@ func TestServerAuthHandlerExpired(t *testing.T) {
 	config.Domains = []string{"test.com"}
 
 	// Should redirect expired cookie
-	req := newDefaultHttpRequest("/foo")
+	req := newHTTPRequest("GET", "http://example.com/foo")
 	c := MakeCookie(req, "test@example.com")
 	res, _ := doHttpRequest(req, c)
-	assert.Equal(307, res.StatusCode, "request with expired cookie should be redirected")
+	require.Equal(t, 307, res.StatusCode, "request with expired cookie should be redirected")
 
 	// Check for CSRF cookie
 	var cookie *http.Cookie
@@ -116,7 +147,7 @@ func TestServerAuthHandlerValid(t *testing.T) {
 	config = newDefaultConfig()
 
 	// Should allow valid request email
-	req := newDefaultHttpRequest("/foo")
+	req := newHTTPRequest("GET", "http://example.com/foo")
 	c := MakeCookie(req, "test@example.com")
 	config.Domains = []string{}
 
@@ -131,6 +162,7 @@ func TestServerAuthHandlerValid(t *testing.T) {
 
 func TestServerAuthCallback(t *testing.T) {
 	assert := assert.New(t)
+	require := require.New(t)
 	config = newDefaultConfig()
 
 	// Setup OAuth server
@@ -148,27 +180,28 @@ func TestServerAuthCallback(t *testing.T) {
 	}
 
 	// Should pass auth response request to callback
-	req := newDefaultHttpRequest("/_oauth")
+	req := newHTTPRequest("GET", "http://example.com/_oauth")
 	res, _ := doHttpRequest(req, nil)
 	assert.Equal(401, res.StatusCode, "auth callback without cookie shouldn't be authorised")
 
 	// Should catch invalid csrf cookie
-	req = newDefaultHttpRequest("/_oauth?state=12345678901234567890123456789012:http://redirect")
+	nonce := "12345678901234567890123456789012"
+	req = newHTTPRequest("GET", "http://example.com/_oauth?state="+nonce+":http://redirect")
 	c := MakeCSRFCookie(req, "nononononononononononononononono")
 	res, _ = doHttpRequest(req, c)
 	assert.Equal(401, res.StatusCode, "auth callback with invalid cookie shouldn't be authorised")
 
 	// Should catch invalid provider cookie
-	req = newDefaultHttpRequest("/_oauth?state=12345678901234567890123456789012:invalid:http://redirect")
-	c = MakeCSRFCookie(req, "12345678901234567890123456789012")
+	req = newHTTPRequest("GET", "http://example.com/_oauth?state="+nonce+":invalid:http://redirect")
+	c = MakeCSRFCookie(req, nonce)
 	res, _ = doHttpRequest(req, c)
 	assert.Equal(401, res.StatusCode, "auth callback with invalid provider shouldn't be authorised")
 
 	// Should redirect valid request
-	req = newDefaultHttpRequest("/_oauth?state=12345678901234567890123456789012:google:http://redirect")
-	c = MakeCSRFCookie(req, "12345678901234567890123456789012")
+	req = newHTTPRequest("GET", "http://example.com/_oauth?state="+nonce+":google:http://redirect")
+	c = MakeCSRFCookie(req, nonce)
 	res, _ = doHttpRequest(req, c)
-	assert.Equal(307, res.StatusCode, "valid auth callback should be allowed")
+	require.Equal(307, res.StatusCode, "valid auth callback should be allowed")
 
 	fwd, _ := res.Location()
 	assert.Equal("http", fwd.Scheme, "valid request should be redirected to return url")
@@ -360,17 +393,17 @@ func TestServerRouteHost(t *testing.T) {
 	}
 
 	// Should block any request
-	req := newHttpRequest("GET", "https://example.com/", "/")
+	req := newHTTPRequest("GET", "https://example.com/")
 	res, _ := doHttpRequest(req, nil)
 	assert.Equal(307, res.StatusCode, "request not matching any rule should require auth")
 
 	// Should allow matching request
-	req = newHttpRequest("GET", "https://api.example.com/", "/")
+	req = newHTTPRequest("GET", "https://api.example.com/")
 	res, _ = doHttpRequest(req, nil)
 	assert.Equal(200, res.StatusCode, "request matching allow rule should be allowed")
 
 	// Should allow matching request
-	req = newHttpRequest("GET", "https://sub8.example.com/", "/")
+	req = newHTTPRequest("GET", "https://sub8.example.com/")
 	res, _ = doHttpRequest(req, nil)
 	assert.Equal(200, res.StatusCode, "request matching allow rule should be allowed")
 }
@@ -386,12 +419,12 @@ func TestServerRouteMethod(t *testing.T) {
 	}
 
 	// Should block any request
-	req := newHttpRequest("GET", "https://example.com/", "/")
+	req := newHTTPRequest("GET", "https://example.com/")
 	res, _ := doHttpRequest(req, nil)
 	assert.Equal(307, res.StatusCode, "request not matching any rule should require auth")
 
 	// Should allow matching request
-	req = newHttpRequest("PUT", "https://example.com/", "/")
+	req = newHTTPRequest("PUT", "https://example.com/")
 	res, _ = doHttpRequest(req, nil)
 	assert.Equal(200, res.StatusCode, "request matching allow rule should be allowed")
 }
@@ -441,12 +474,12 @@ func TestServerRouteQuery(t *testing.T) {
 	}
 
 	// Should block any request
-	req := newHttpRequest("GET", "https://example.com/", "/?q=no")
+	req := newHTTPRequest("GET", "https://example.com/?q=no")
 	res, _ := doHttpRequest(req, nil)
 	assert.Equal(307, res.StatusCode, "request not matching any rule should require auth")
 
 	// Should allow matching request
-	req = newHttpRequest("GET", "https://api.example.com/", "/?q=test123")
+	req = newHTTPRequest("GET", "https://api.example.com/?q=test123")
 	res, _ = doHttpRequest(req, nil)
 	assert.Equal(200, res.StatusCode, "request matching allow rule should be allowed")
 }
@@ -531,16 +564,17 @@ func newDefaultConfig() *Config {
 	return config
 }
 
+// TODO: replace with newHTTPRequest("GET", "http://example.com/"+uri)
 func newDefaultHttpRequest(uri string) *http.Request {
-	return newHttpRequest("", "http://example.com/", uri)
+	return newHTTPRequest("GET", "http://example.com"+uri)
 }
 
-func newHttpRequest(method, dest, uri string) *http.Request {
-	r := httptest.NewRequest("", "http://should-use-x-forwarded.com", nil)
-	p, _ := url.Parse(dest)
+func newHTTPRequest(method, target string) *http.Request {
+	u, _ := url.Parse(target)
+	r := httptest.NewRequest(method, target, nil)
 	r.Header.Add("X-Forwarded-Method", method)
-	r.Header.Add("X-Forwarded-Proto", p.Scheme)
-	r.Header.Add("X-Forwarded-Host", p.Host)
-	r.Header.Add("X-Forwarded-Uri", uri)
+	r.Header.Add("X-Forwarded-Proto", u.Scheme)
+	r.Header.Add("X-Forwarded-Host", u.Host)
+	r.Header.Add("X-Forwarded-Uri", u.RequestURI())
 	return r
 }