TUN-1250: ValidateHTTPService shouldn't follow 302s

validation/validation.go

@@ -144,15 +144,20 @@ func ValidateHTTPService(originURL string, hostname string, transport http.Round
 		return err
 	}
 
-	client := &http.Client{Transport: transport}
+	client := &http.Client{
+		Transport: transport,
+		CheckRedirect: func(req *http.Request, via []*http.Request) error {
+			return http.ErrUseLastResponse
+		},
+	}
 
 	initialRequest, err := http.NewRequest("GET", parsedURL.String(), nil)
 	if err != nil {
 		return err
 	}
 	initialRequest.Host = hostname
-	initialResponse, initialErr := client.Do(initialRequest)
-	if initialErr != nil || initialResponse.StatusCode != http.StatusOK {
+	_, initialErr := client.Do(initialRequest)
+	if initialErr != nil {
 		// Attempt the same endpoint via the other protocol (http/https); maybe we have better luck?
 		oldScheme := parsedURL.Scheme
 		parsedURL.Scheme = toggleProtocol(parsedURL.Scheme)
@@ -162,8 +167,8 @@ func ValidateHTTPService(originURL string, hostname string, transport http.Round
 			return err
 		}
 		secondRequest.Host = hostname
-		secondResponse, _ := client.Do(secondRequest)
-		if secondResponse != nil && secondResponse.StatusCode == http.StatusOK { // Worked this time--advise the user to switch protocols
+		_, secondErr := client.Do(secondRequest)
+		if secondErr == nil { // Worked this time--advise the user to switch protocols
 			return errors.Errorf(
 				"%s doesn't seem to work over %s, but does seem to work over %s. Consider changing the origin URL to %s",
 				parsedURL.Host,

validation/validation_test.go

@@ -1,7 +1,9 @@
 package validation
 
 import (
+	"bytes"
 	"fmt"
+	"io/ioutil"
 	"testing"
 
 	"context"
@@ -151,58 +153,89 @@ func TestToggleProtocol(t *testing.T) {
 	assert.Equal(t, "", toggleProtocol(""))
 }
 
+// Happy path 1: originURL is HTTP, and HTTP connections work
 func TestValidateHTTPService_HTTP2HTTP(t *testing.T) {
 	originURL := "http://127.0.0.1/"
 	hostname := "example.com"
+
+	assert.Nil(t, ValidateHTTPService(originURL, hostname, testRoundTripper(func(req *http.Request) (*http.Response, error) {
+		assert.Equal(t, req.Host, hostname)
+		if req.URL.Scheme == "http" {
+			return emptyResponse(200), nil
+		}
+		if req.URL.Scheme == "https" {
+			t.Fatal("http works, shouldn't have tried with https")
+		}
+		panic("Shouldn't reach here")
+	})))
+
+	assert.Nil(t, ValidateHTTPService(originURL, hostname, testRoundTripper(func(req *http.Request) (*http.Response, error) {
+		assert.Equal(t, req.Host, hostname)
+		if req.URL.Scheme == "http" {
+			return emptyResponse(503), nil
+		}
+		if req.URL.Scheme == "https" {
+			t.Fatal("http works, shouldn't have tried with https")
+		}
+		panic("Shouldn't reach here")
+	})))
+
+	// Integration-style test with a mock server
 	server, client, err := createMockServerAndClient(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		assert.Equal(t, hostname, r.Host)
 		w.WriteHeader(200)
 	}))
 	assert.NoError(t, err)
 	defer server.Close()
+	assert.Nil(t, ValidateHTTPService(originURL, hostname, client.Transport))
 
-	assert.Equal(t, nil, ValidateHTTPService(originURL, hostname, client.Transport))
-}
-
-func TestValidateHTTPService_ServerNonOKResponse(t *testing.T) {
-	originURL := "http://127.0.0.1/"
-	hostname := "example.com"
-	server, client, err := createMockServerAndClient(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+	// this will fail if the client follows the 302
+	redirectServer, redirectClient, err := createMockServerAndClient(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/followedRedirect" {
+			t.Fatal("shouldn't have followed the 302")
+		}
 		if r.Method == "CONNECT" {
 			assert.Equal(t, "127.0.0.1:443", r.Host)
 		} else {
 			assert.Equal(t, hostname, r.Host)
 		}
-		w.WriteHeader(400)
+		w.Header().Set("Location", "/followedRedirect")
+		w.WriteHeader(302)
 	}))
 	assert.NoError(t, err)
-	defer server.Close()
+	defer redirectServer.Close()
+	assert.Nil(t, ValidateHTTPService(originURL, hostname, redirectClient.Transport))
 
-	assert.Equal(t, nil, ValidateHTTPService(originURL, hostname, client.Transport))
-}
-
-func TestValidateHTTPService_HTTPS2HTTP(t *testing.T) {
-	originURL := "https://127.0.0.1:1234/"
-	hostname := "example.com"
-	server, client, err := createMockServerAndClient(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		if r.Method == "CONNECT" {
-			assert.Equal(t, "127.0.0.1:1234", r.Host)
-		} else {
-			assert.Equal(t, hostname, r.Host)
-		}
-		w.WriteHeader(200)
-	}))
-	assert.NoError(t, err)
-	defer server.Close()
-
-	assert.Equal(t,
-		"127.0.0.1:1234 doesn't seem to work over https, but does seem to work over http. Consider changing the origin URL to http://127.0.0.1:1234/",
-		ValidateHTTPService(originURL, hostname, client.Transport).Error())
 }
 
+// Happy path 2: originURL is HTTPS, and HTTPS connections work
 func TestValidateHTTPService_HTTPS2HTTPS(t *testing.T) {
 	originURL := "https://127.0.0.1/"
 	hostname := "example.com"
+
+	assert.Nil(t, ValidateHTTPService(originURL, hostname, testRoundTripper(func(req *http.Request) (*http.Response, error) {
+		assert.Equal(t, req.Host, hostname)
+		if req.URL.Scheme == "http" {
+			t.Fatal("https works, shouldn't have tried with http")
+		}
+		if req.URL.Scheme == "https" {
+			return emptyResponse(200), nil
+		}
+		panic("Shouldn't reach here")
+	})))
+
+	assert.Nil(t, ValidateHTTPService(originURL, hostname, testRoundTripper(func(req *http.Request) (*http.Response, error) {
+		assert.Equal(t, req.Host, hostname)
+		if req.URL.Scheme == "http" {
+			t.Fatal("https works, shouldn't have tried with http")
+		}
+		if req.URL.Scheme == "https" {
+			return emptyResponse(503), nil
+		}
+		panic("Shouldn't reach here")
+	})))
+
+	// Integration-style test with a mock server
 	server, client, err := createSecureMockServerAndClient(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		if r.Method == "CONNECT" {
 			assert.Equal(t, "127.0.0.1:443", r.Host)
@@ -213,13 +246,113 @@ func TestValidateHTTPService_HTTPS2HTTPS(t *testing.T) {
 	}))
 	assert.NoError(t, err)
 	defer server.Close()
+	assert.Nil(t, ValidateHTTPService(originURL, hostname, client.Transport))
 
-	assert.Equal(t, nil, ValidateHTTPService(originURL, hostname, client.Transport))
+	// this will fail if the client follows the 302
+	redirectServer, redirectClient, err := createSecureMockServerAndClient(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/followedRedirect" {
+			t.Fatal("shouldn't have followed the 302")
+		}
+		if r.Method == "CONNECT" {
+			assert.Equal(t, "127.0.0.1:443", r.Host)
+		} else {
+			assert.Equal(t, hostname, r.Host)
+		}
+		w.Header().Set("Location", "/followedRedirect")
+		w.WriteHeader(302)
+	}))
+	assert.NoError(t, err)
+	defer redirectServer.Close()
+	assert.Nil(t, ValidateHTTPService(originURL, hostname, redirectClient.Transport))
 }
 
+// Error path 1: originURL is HTTPS, but HTTP connections work
+func TestValidateHTTPService_HTTPS2HTTP(t *testing.T) {
+	originURL := "https://127.0.0.1:1234/"
+	hostname := "example.com"
+
+	assert.Error(t, ValidateHTTPService(originURL, hostname, testRoundTripper(func(req *http.Request) (*http.Response, error) {
+		assert.Equal(t, req.Host, hostname)
+		if req.URL.Scheme == "http" {
+			return emptyResponse(200), nil
+		}
+		if req.URL.Scheme == "https" {
+			return nil, assert.AnError
+		}
+		panic("Shouldn't reach here")
+	})))
+
+	assert.Error(t, ValidateHTTPService(originURL, hostname, testRoundTripper(func(req *http.Request) (*http.Response, error) {
+		assert.Equal(t, req.Host, hostname)
+		if req.URL.Scheme == "http" {
+			return emptyResponse(503), nil
+		}
+		if req.URL.Scheme == "https" {
+			return nil, assert.AnError
+		}
+		panic("Shouldn't reach here")
+	})))
+
+	// Integration-style test with a mock server
+	server, client, err := createMockServerAndClient(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.Method == "CONNECT" {
+			assert.Equal(t, "127.0.0.1:1234", r.Host)
+		} else {
+			assert.Equal(t, hostname, r.Host)
+		}
+		w.WriteHeader(200)
+	}))
+	assert.NoError(t, err)
+	defer server.Close()
+	assert.Error(t, ValidateHTTPService(originURL, hostname, client.Transport))
+
+	// this will fail if the client follows the 302
+	redirectServer, redirectClient, err := createMockServerAndClient(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/followedRedirect" {
+			t.Fatal("shouldn't have followed the 302")
+		}
+		if r.Method == "CONNECT" {
+			assert.Equal(t, "127.0.0.1:1234", r.Host)
+		} else {
+			assert.Equal(t, hostname, r.Host)
+		}
+		w.Header().Set("Location", "/followedRedirect")
+		w.WriteHeader(302)
+	}))
+	assert.NoError(t, err)
+	defer redirectServer.Close()
+	assert.Error(t, ValidateHTTPService(originURL, hostname, redirectClient.Transport))
+
+}
+
+// Error path 2: originURL is HTTP, but HTTPS connections work
 func TestValidateHTTPService_HTTP2HTTPS(t *testing.T) {
 	originURL := "http://127.0.0.1:1234/"
 	hostname := "example.com"
+
+	assert.Error(t, ValidateHTTPService(originURL, hostname, testRoundTripper(func(req *http.Request) (*http.Response, error) {
+		assert.Equal(t, req.Host, hostname)
+		if req.URL.Scheme == "http" {
+			return nil, assert.AnError
+		}
+		if req.URL.Scheme == "https" {
+			return emptyResponse(200), nil
+		}
+		panic("Shouldn't reach here")
+	})))
+
+	assert.Error(t, ValidateHTTPService(originURL, hostname, testRoundTripper(func(req *http.Request) (*http.Response, error) {
+		assert.Equal(t, req.Host, hostname)
+		if req.URL.Scheme == "http" {
+			return nil, assert.AnError
+		}
+		if req.URL.Scheme == "https" {
+			return emptyResponse(503), nil
+		}
+		panic("Shouldn't reach here")
+	})))
+
+	// Integration-style test with a mock server
 	server, client, err := createSecureMockServerAndClient(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		if r.Method == "CONNECT" {
 			assert.Equal(t, "127.0.0.1:1234", r.Host)
@@ -230,10 +363,38 @@ func TestValidateHTTPService_HTTP2HTTPS(t *testing.T) {
 	}))
 	assert.NoError(t, err)
 	defer server.Close()
+	assert.Error(t, ValidateHTTPService(originURL, hostname, client.Transport))
 
-	assert.Equal(t,
-		"127.0.0.1:1234 doesn't seem to work over http, but does seem to work over https. Consider changing the origin URL to https://127.0.0.1:1234/",
-		ValidateHTTPService(originURL, hostname, client.Transport).Error())
+	// this will fail if the client follows the 302
+	redirectServer, redirectClient, err := createSecureMockServerAndClient(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.URL.Path == "/followedRedirect" {
+			t.Fatal("shouldn't have followed the 302")
+		}
+		if r.Method == "CONNECT" {
+			assert.Equal(t, "127.0.0.1:443", r.Host)
+		} else {
+			assert.Equal(t, hostname, r.Host)
+		}
+		w.Header().Set("Location", "/followedRedirect")
+		w.WriteHeader(302)
+	}))
+	assert.NoError(t, err)
+	defer redirectServer.Close()
+	assert.Error(t, ValidateHTTPService(originURL, hostname, redirectClient.Transport))
+}
+
+type testRoundTripper func(req *http.Request) (*http.Response, error)
+
+func (f testRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
+	return f(req)
+}
+
+func emptyResponse(statusCode int) *http.Response {
+	return &http.Response{
+		StatusCode: statusCode,
+		Body:       ioutil.NopCloser(bytes.NewReader(nil)),
+		Header:     make(http.Header),
+	}
 }
 
 func createMockServerAndClient(handler http.Handler) (*httptest.Server, *http.Client, error) {