From e24997a0028ff928412abd0294e52693fd4570eb Mon Sep 17 00:00:00 2001
From: p53 <pavol.ipoth@protonmail.com>
Date: Sun, 21 Jul 2024 13:38:30 +0200
Subject: [PATCH] Enable to forward-auth to work with static authz (#488)

---
 pkg/keycloak/proxy/server.go |  4 ++++
 pkg/proxy/middleware/base.go | 20 ++++++++++++++++++++
 pkg/testsuite/server_test.go | 34 +++++++++++++++++++++++++++++++---
 3 files changed, 55 insertions(+), 3 deletions(-)

diff --git a/pkg/keycloak/proxy/server.go b/pkg/keycloak/proxy/server.go
index 4baf98d2..f82a7c11 100644
--- a/pkg/keycloak/proxy/server.go
+++ b/pkg/keycloak/proxy/server.go
@@ -247,6 +247,10 @@ func (r *OauthProxy) useDefaultStack(engine chi.Router) {
 	// @step: enable the entrypoint middleware
 	engine.Use(gmiddleware.EntrypointMiddleware(r.Log))
 
+	if r.Config.NoProxy {
+		engine.Use(gmiddleware.ForwardAuthMiddleware(r.Log, r.Config.OAuthURI))
+	}
+
 	if r.Config.EnableLogging {
 		engine.Use(gmiddleware.LoggingMiddleware(r.Log, r.Config.Verbose))
 	}
diff --git a/pkg/proxy/middleware/base.go b/pkg/proxy/middleware/base.go
index e9822621..99ebfe55 100644
--- a/pkg/proxy/middleware/base.go
+++ b/pkg/proxy/middleware/base.go
@@ -372,3 +372,23 @@ func ProxyMiddleware(
 		})
 	}
 }
+
+// ForwardAuthMiddleware
+func ForwardAuthMiddleware(logger *zap.Logger, oAuthURI string) func(http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		logger.Info("enabling the forward-auth middleware")
+
+		return http.HandlerFunc(func(wrt http.ResponseWriter, req *http.Request) {
+			if !strings.Contains(req.URL.Path, oAuthURI) { // this condition is here only because of tests to work
+				if forwardedPath := req.Header.Get("X-Forwarded-Uri"); forwardedPath != "" {
+					req.URL.Path = forwardedPath
+					req.URL.RawPath = forwardedPath
+				}
+				if forwardedMethod := req.Header.Get("X-Forwarded-Method"); forwardedMethod != "" {
+					req.Method = forwardedMethod
+				}
+			}
+			next.ServeHTTP(wrt, req)
+		})
+	}
+}
diff --git a/pkg/testsuite/server_test.go b/pkg/testsuite/server_test.go
index 8f193b11..70d7cd86 100644
--- a/pkg/testsuite/server_test.go
+++ b/pkg/testsuite/server_test.go
@@ -1354,6 +1354,7 @@ func TestNoProxy(t *testing.T) {
 					ExpectedContent: func(body string, testNum int) {
 						assert.Equal(t, "", body)
 					},
+					ExpectedLocation: "https://thiswillbereplaced/oauth",
 					Headers: map[string]string{
 						"X-Forwarded-Host":  "thiswillbereplaced",
 						"X-Forwarded-Proto": "https",
@@ -1394,10 +1395,15 @@ func TestNoProxy(t *testing.T) {
 		{
 			Name: "TestNoProxyWithRedirectsPrivateAuthenticated",
 			ProxySettings: func(c *config.Config) {
-				c.EnableDefaultDeny = true
+				c.EnableDefaultDeny = false
 				c.NoRedirects = false
 				c.NoProxy = true
 				c.Resources = []*authorization.Resource{
+					{
+						URL:     "/*",
+						Methods: utils.AllHTTPMethods,
+						Roles:   []string{"user"},
+					},
 					{
 						URL:         "/public/*",
 						Methods:     utils.AllHTTPMethods,
@@ -1405,13 +1411,16 @@ func TestNoProxy(t *testing.T) {
 					},
 					{
 						URL:     "/private",
-						Methods: []string{"GET"},
+						Methods: []string{"POST"},
 					},
 				}
 			},
 			ExecutionSettings: []fakeRequest{
 				{
-					URI:             "/private",
+					// forward-auth will send / as path always so we are simulating it
+					// real path will be sent in X-Forwarded-Uri, which should be
+					// injected to request path in forward-auth middleware
+					URI:             "/",
 					ExpectedProxy:   false,
 					HasLogin:        true,
 					LoginXforwarded: true,
@@ -1420,6 +1429,25 @@ func TestNoProxy(t *testing.T) {
 					ExpectedContent: func(body string, testNum int) {
 						assert.Equal(t, "", body)
 					},
+					Headers: map[string]string{
+						"X-Forwarded-Uri":    "/private",
+						"X-Forwarded-Method": "POST",
+					},
+				},
+				{
+					URI:             "/",
+					ExpectedProxy:   false,
+					HasLogin:        true,
+					LoginXforwarded: true,
+					Redirects:       true,
+					ExpectedCode:    http.StatusForbidden,
+					ExpectedContent: func(body string, testNum int) {
+						assert.Equal(t, "", body)
+					},
+					Headers: map[string]string{
+						"X-Forwarded-Uri":    "/private",
+						"X-Forwarded-Method": "DELETE",
+					},
 				},
 			},
 		},