Fix X-Forwarded-Host overwriting (#521)

Author: p53

pkg/constant/constant.go

@@ -51,9 +51,10 @@ const (
 
 	_ contextKey = iota
 	ContextScopeName
-	HeaderXForwardedFor = "X-Forwarded-For"
-	HeaderXRealIP       = "X-Real-IP"
-	HeaderXHMAC         = "X-HMAC-SHA256"
+	HeaderXForwardedFor  = "X-Forwarded-For"
+	HeaderXForwardedHost = "X-Forwarded-Host"
+	HeaderXRealIP        = "X-Real-IP"
+	HeaderXHMAC          = "X-HMAC-SHA256"
 
 	DurationType = "time.Duration"
 

pkg/proxy/middleware/base.go

@@ -322,12 +322,11 @@ func ProxyMiddleware(
 			// @step: add the proxy forwarding headers
 			req.Header.Set("X-Real-IP", utils.RealIP(req))
 			if xff := req.Header.Get(constant.HeaderXForwardedFor); xff == "" {
-				req.Header.Set("X-Forwarded-For", utils.RealIP(req))
-			} else {
-				req.Header.Set("X-Forwarded-For", xff)
+				req.Header.Set(constant.HeaderXForwardedFor, utils.RealIP(req))
+			}
+			if xfh := req.Header.Get(constant.HeaderXForwardedHost); xfh == "" {
+				req.Header.Set(constant.HeaderXForwardedHost, req.Host)
 			}
-			req.Header.Set("X-Forwarded-Host", req.Host)
-			req.Header.Set("X-Forwarded-Proto", req.Header.Get("X-Forwarded-Proto"))
 
 			if len(corsOrigins) > 0 {
 				// if CORS is enabled by Gatekeeper, do not propagate CORS requests upstream

pkg/testsuite/server_test.go

@@ -1518,7 +1518,7 @@ func TestXForwarded(t *testing.T) {
 		ExecutionSettings []fakeRequest
 	}{
 		{
-			Name: "TestEmptyXForwarded",
+			Name: "TestEmptyXForwardedFor",
 			ProxySettings: func(_ *config.Config) {
 			},
 			ExecutionSettings: []fakeRequest{
@@ -1535,7 +1535,7 @@ func TestXForwarded(t *testing.T) {
 			},
 		},
 		{
-			Name: "TestXForwardedPresent",
+			Name: "TestXForwardedForPresent",
 			ProxySettings: func(_ *config.Config) {
 			},
 			ExecutionSettings: []fakeRequest{
@@ -1574,6 +1574,43 @@ func TestXForwarded(t *testing.T) {
 				},
 			},
 		},
+		{
+			Name: "TestEmptyXForwardedHost",
+			ProxySettings: func(_ *config.Config) {
+			},
+			ExecutionSettings: []fakeRequest{
+				{
+					URI:           FakeAuthAllURL + FakeTestURL,
+					HasToken:      true,
+					ExpectedProxy: true,
+					ExpectedProxyHeadersValidator: map[string]func(*testing.T, *config.Config, string){
+						"X-Forwarded-Host": func(t *testing.T, _ *config.Config, value string) {
+							assert.Contains(t, value, "127.0.0.1")
+						},
+					},
+					ExpectedCode: http.StatusOK,
+				},
+			},
+		},
+		{
+			Name: "TestXForwardedHostPresent",
+			ProxySettings: func(_ *config.Config) {
+			},
+			ExecutionSettings: []fakeRequest{
+				{
+					URI:           FakeAuthAllURL + FakeTestURL,
+					HasToken:      true,
+					ExpectedProxy: true,
+					Headers: map[string]string{
+						"X-Forwarded-Host": "189.10.10.1",
+					},
+					ExpectedProxyHeaders: map[string]string{
+						"X-Forwarded-Host": "189.10.10.1",
+					},
+					ExpectedCode: http.StatusOK,
+				},
+			},
+		},
 	}
 
 	for _, testCase := range testCases {