do not force hostname validation for test keys

Author: joecorall

main.go

@@ -38,8 +38,23 @@ const (
 	DefaultHealthCheckFailureThreshold = 0 // Number of consecutive health check failures before opening circuit
 	goodBotLookupTimeout               = 2 * time.Second
 	maxCaptchaChallengeAge             = 5 * time.Minute
+	turnstileTestHostname              = "example.com"
 )
 
+var turnstileTestSiteKeys = map[string]struct{}{
+	"1x00000000000000000000AA": {},
+	"2x00000000000000000000AB": {},
+	"1x00000000000000000000BB": {},
+	"2x00000000000000000000BB": {},
+	"3x00000000000000000000FF": {},
+}
+
+var turnstileTestSecretKeys = map[string]struct{}{
+	"1x0000000000000000000000000000000AA": {},
+	"2x0000000000000000000000000000000AA": {},
+	"3x0000000000000000000000000000000AA": {},
+}
+
 type circuitState int
 
 const (
@@ -696,7 +711,8 @@ func (bc *CaptchaProtect) verifyChallengePage(rw http.ResponseWriter, req *http.
 		success = captchaResponse.Success
 		if success && activeConfig.key == "cf-turnstile" {
 			expectedHostname := captchaValidationHostname(req)
-			if captchaResponse.Hostname != expectedHostname {
+			skipHostnameValidation := bc.usesTurnstileTestKeys() && captchaResponse.Hostname == turnstileTestHostname
+			if !skipHostnameValidation && captchaResponse.Hostname != expectedHostname {
 				bc.log.Warn("captcha hostname mismatch", "hostname", captchaResponse.Hostname, "expectedHostname", expectedHostname)
 				success = false
 			} else {
@@ -743,6 +759,12 @@ func captchaValidationHostname(req *http.Request) string {
 	return host
 }
 
+func (bc *CaptchaProtect) usesTurnstileTestKeys() bool {
+	_, hasTestSiteKey := turnstileTestSiteKeys[bc.config.SiteKey]
+	_, hasTestSecretKey := turnstileTestSecretKeys[bc.config.SecretKey]
+	return hasTestSiteKey && hasTestSecretKey
+}
+
 func randomUUID() (string, error) {
 	var b [16]byte
 	if _, err := crand.Read(b[:]); err != nil {

main_test.go

@@ -1161,6 +1161,74 @@ func TestVerifyChallengePageRejectsInvalidSiteverifyMetadata(t *testing.T) {
 	}
 }
 
+func TestVerifyChallengePageAllowsTurnstileTestKeysExampleHostname(t *testing.T) {
+	validChallengeTS := time.Now().Format(time.RFC3339Nano)
+	mockResponse := fmt.Sprintf(`{"success":true,"hostname":"example.com","challenge_ts":%q}`, validChallengeTS)
+
+	mockServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		_, _ = w.Write([]byte(mockResponse))
+	}))
+	defer mockServer.Close()
+
+	config := CreateConfig()
+	config.SiteKey = "1x00000000000000000000AA"
+	config.SecretKey = "1x0000000000000000000000000000000AA"
+	config.ProtectRoutes = []string{"/"}
+	config.CaptchaProvider = "turnstile"
+
+	bc, _ := NewCaptchaProtect(context.Background(), nil, config, "test")
+	bc.captchaConfig.validate = mockServer.URL
+
+	req := httptest.NewRequest(http.MethodPost, "http://localhost/challenge", nil)
+	req.Form = make(map[string][]string)
+	req.Form.Set("cf-turnstile-response", "valid-token")
+
+	rr := httptest.NewRecorder()
+	status := bc.verifyChallengePage(rr, req, "1.2.3.4")
+
+	if status != http.StatusFound {
+		t.Fatalf("expected status %d, got %d", http.StatusFound, status)
+	}
+	if _, found := bc.verifiedCache.Get("1.2.3.4"); !found {
+		t.Fatal("expected turnstile test key response to set verified cache")
+	}
+}
+
+func TestVerifyChallengePageRejectsExampleHostnameWithoutTurnstileTestKeys(t *testing.T) {
+	validChallengeTS := time.Now().Format(time.RFC3339Nano)
+	mockResponse := fmt.Sprintf(`{"success":true,"hostname":"example.com","challenge_ts":%q}`, validChallengeTS)
+
+	mockServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Content-Type", "application/json")
+		_, _ = w.Write([]byte(mockResponse))
+	}))
+	defer mockServer.Close()
+
+	config := CreateConfig()
+	config.SiteKey = "test"
+	config.SecretKey = "test"
+	config.ProtectRoutes = []string{"/"}
+	config.CaptchaProvider = "turnstile"
+
+	bc, _ := NewCaptchaProtect(context.Background(), nil, config, "test")
+	bc.captchaConfig.validate = mockServer.URL
+
+	req := httptest.NewRequest(http.MethodPost, "http://localhost/challenge", nil)
+	req.Form = make(map[string][]string)
+	req.Form.Set("cf-turnstile-response", "valid-token")
+
+	rr := httptest.NewRecorder()
+	status := bc.verifyChallengePage(rr, req, "1.2.3.4")
+
+	if status != http.StatusForbidden {
+		t.Fatalf("expected status %d, got %d", http.StatusForbidden, status)
+	}
+	if _, found := bc.verifiedCache.Get("1.2.3.4"); found {
+		t.Fatal("did not expect non-test key response to set verified cache")
+	}
+}
+
 func TestVerifyChallengePageAllowsNonTurnstileWithoutMetadata(t *testing.T) {
 	mockServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "application/json")