fixes #131: correctly instantiate GREASE Extension when using more th…

…an one GREASE Extension in ja3;

example/main.go

@@ -25,6 +25,7 @@ func main() {
 	postAsTlsClient()
 	requestWithFollowRedirectSwitch()
 	requestWithCustomClient()
+	requestWithJa3CustomClientWithTwoGreaseExtensions()
 	rotateProxiesOnClient()
 	downloadImageWithTlsClient()
 	testPskExtension()
@@ -689,6 +690,103 @@ func requestWithCustomClient() {
 	log.Printf("requesting topps as customClient1 => status code: %d\n", resp.StatusCode)
 }
 
+func requestWithJa3CustomClientWithTwoGreaseExtensions() {
+	settings := map[http2.SettingID]uint32{
+		http2.SettingHeaderTableSize:   65536,
+		http2.SettingEnablePush:        0,
+		http2.SettingInitialWindowSize: 6291456,
+		http2.SettingMaxHeaderListSize: 262144,
+	}
+	settingsOrder := []http2.SettingID{
+		http2.SettingHeaderTableSize,
+		http2.SettingEnablePush,
+		http2.SettingInitialWindowSize,
+		http2.SettingMaxHeaderListSize,
+	}
+
+	pseudoHeaderOrder := []string{
+		":method",
+		":authority",
+		":scheme",
+		":path",
+	}
+
+	connectionFlow := uint32(15663105)
+
+	ja3String := "771,2570-4865-4866-4867-49195-49199-49196-49200-52393-52392-49171-49172-156-157-47-53,2570-18-5-27-11-0-10-35-16-65037-51-13-23-43-17513-65281-45-2570,2570-25497-29-23-24,0"
+
+	supportedSignatureAlgorithms := []string{
+		"ECDSAWithP256AndSHA256",
+		"PSSWithSHA256",
+		"PKCS1WithSHA256",
+		"ECDSAWithP384AndSHA384",
+		"PSSWithSHA384",
+		"PKCS1WithSHA384",
+		"PSSWithSHA512",
+		"PKCS1WithSHA512",
+	}
+	var supportedDelegatedCredentialsAlgorithms []string
+	supportedVersions := []string{"GREASE", "1.3", "1.2"}
+	keyShareCurves := []string{"GREASE", "X25519Kyber768", "X25519"}
+	supportedProtocolsALPN := []string{"h2", "http/1.1"}
+	supportedProtocolsALPS := []string{"h2"}
+	echCandidateCipherSuites := []tls_client.CandidateCipherSuites{
+		{
+			KdfId:  "HKDF_SHA256",
+			AeadId: "AEAD_AES_128_GCM",
+		},
+		{
+			KdfId:  "HKDF_SHA256",
+			AeadId: "AEAD_CHACHA20_POLY1305",
+		},
+	}
+	candidatePayloads := []uint16{128, 160, 192, 224}
+	certCompressionAlgo := "brotli"
+
+	specFactory, err := tls_client.GetSpecFactoryFromJa3String(ja3String, supportedSignatureAlgorithms, supportedDelegatedCredentialsAlgorithms, supportedVersions, keyShareCurves, supportedProtocolsALPN, supportedProtocolsALPS, echCandidateCipherSuites, candidatePayloads, certCompressionAlgo)
+
+	customClientProfile := profiles.NewClientProfile(tls.ClientHelloID{
+		Client:      "MyCustomProfile",
+		Version:     "1",
+		Seed:        nil,
+		SpecFactory: specFactory,
+	}, settings, settingsOrder, pseudoHeaderOrder, connectionFlow, nil, nil)
+
+	options := []tls_client.HttpClientOption{
+		tls_client.WithTimeoutSeconds(60),
+		tls_client.WithClientProfile(customClientProfile), // use custom profile here
+	}
+
+	client, err := tls_client.NewHttpClient(tls_client.NewNoopLogger(), options...)
+	if err != nil {
+		log.Println(err)
+		return
+	}
+
+	req, err := http.NewRequest(http.MethodGet, "https://tls.browserleaks.com/tls", nil)
+	if err != nil {
+		log.Println(err)
+		return
+	}
+
+	resp, err := client.Do(req)
+	if err != nil {
+		log.Println(err)
+		return
+	}
+
+	defer resp.Body.Close()
+
+	readBytes, err := io.ReadAll(resp.Body)
+	if err != nil {
+		log.Println(err)
+		return
+	}
+
+	log.Printf(string(readBytes))
+	log.Printf("status code: %d\n", resp.StatusCode)
+}
+
 func testPskExtension() {
 	settings := map[http2.SettingID]uint32{
 		http2.SettingHeaderTableSize:      65536,

ja3.go

@@ -193,6 +193,12 @@ func stringToSpec(ja3 string, signatureAlgorithms []tls.SignatureScheme, delegat
 			return tls.ClientHelloSpec{}, err
 		}
 
+		if uint16(eId) == tls.GREASE_PLACEHOLDER {
+			// if we use multiple grease extensions with need to generate always a new value. therefore we are creating a new instance here
+			exts = append(exts, &tls.UtlsGREASEExtension{})
+			continue
+		}
+
 		te, ok := extMap[uint16(eId)]
 		if !ok {
 			return tls.ClientHelloSpec{}, fmt.Errorf("unknown extension with id %s provided", e)
@@ -211,15 +217,17 @@ func stringToSpec(ja3 string, signatureAlgorithms []tls.SignatureScheme, delegat
 
 	return tls.ClientHelloSpec{
 		CipherSuites:       suites,
-		CompressionMethods: []byte{0},
+		CompressionMethods: []byte{tls.CompressionNone},
 		Extensions:         exts,
 		GetSessionID:       sha256.Sum256,
 	}, nil
 }
 
 func getExtensionBaseMap() map[uint16]tls.TLSExtension {
 	return map[uint16]tls.TLSExtension{
-		tls.GREASE_PLACEHOLDER:     &tls.UtlsGREASEExtension{},
+		// This extension needs to be instantiated every time and not be reused if it occurs multiple times in the same ja3
+		//tls.GREASE_PLACEHOLDER:     &tls.UtlsGREASEExtension{},
+
 		tls.ExtensionServerName:    &tls.SNIExtension{},
 		tls.ExtensionStatusRequest: &tls.StatusRequestExtension{},