feat: add ech-key for listeners

component/ech/key.go

@@ -0,0 +1,143 @@
+package ech
+
+import (
+	"crypto/ecdh"
+	"crypto/rand"
+	"encoding/base64"
+	"encoding/pem"
+	"errors"
+	"fmt"
+	"os"
+
+	"github.com/metacubex/mihomo/component/ca"
+	tlsC "github.com/metacubex/mihomo/component/tls"
+
+	"golang.org/x/crypto/cryptobyte"
+)
+
+const (
+	AEAD_AES_128_GCM      = 0x0001
+	AEAD_AES_256_GCM      = 0x0002
+	AEAD_ChaCha20Poly1305 = 0x0003
+)
+
+const extensionEncryptedClientHello = 0xfe0d
+const DHKEM_X25519_HKDF_SHA256 = 0x0020
+const KDF_HKDF_SHA256 = 0x0001
+
+// sortedSupportedAEADs is just a sorted version of hpke.SupportedAEADS.
+// We need this so that when we insert them into ECHConfigs the ordering
+// is stable.
+var sortedSupportedAEADs = []uint16{AEAD_AES_128_GCM, AEAD_AES_256_GCM, AEAD_ChaCha20Poly1305}
+
+func marshalECHConfig(id uint8, pubKey []byte, publicName string, maxNameLen uint8) []byte {
+	builder := cryptobyte.NewBuilder(nil)
+
+	builder.AddUint16(extensionEncryptedClientHello)
+	builder.AddUint16LengthPrefixed(func(builder *cryptobyte.Builder) {
+		builder.AddUint8(id)
+
+		builder.AddUint16(DHKEM_X25519_HKDF_SHA256) // The only DHKEM we support
+		builder.AddUint16LengthPrefixed(func(builder *cryptobyte.Builder) {
+			builder.AddBytes(pubKey)
+		})
+		builder.AddUint16LengthPrefixed(func(builder *cryptobyte.Builder) {
+			for _, aeadID := range sortedSupportedAEADs {
+				builder.AddUint16(KDF_HKDF_SHA256) // The only KDF we support
+				builder.AddUint16(aeadID)
+			}
+		})
+		builder.AddUint8(maxNameLen)
+		builder.AddUint8LengthPrefixed(func(builder *cryptobyte.Builder) {
+			builder.AddBytes([]byte(publicName))
+		})
+		builder.AddUint16(0) // extensions
+	})
+
+	return builder.BytesOrPanic()
+}
+
+func GenECHConfig(publicName string) (configBase64 string, keyPem string, err error) {
+	echKey, err := ecdh.X25519().GenerateKey(rand.Reader)
+	if err != nil {
+		return
+	}
+
+	echConfig := marshalECHConfig(0, echKey.PublicKey().Bytes(), publicName, 0)
+
+	builder := cryptobyte.NewBuilder(nil)
+	builder.AddUint16LengthPrefixed(func(builder *cryptobyte.Builder) {
+		builder.AddBytes(echConfig)
+	})
+	echConfigList := builder.BytesOrPanic()
+
+	builder2 := cryptobyte.NewBuilder(nil)
+	builder2.AddUint16LengthPrefixed(func(builder *cryptobyte.Builder) {
+		builder.AddBytes(echKey.Bytes())
+	})
+	builder2.AddUint16LengthPrefixed(func(builder *cryptobyte.Builder) {
+		builder.AddBytes(echConfig)
+	})
+	echConfigKeys := builder2.BytesOrPanic()
+
+	configBase64 = base64.StdEncoding.EncodeToString(echConfigList)
+	keyPem = string(pem.EncodeToMemory(&pem.Block{Type: "ECH KEYS", Bytes: echConfigKeys}))
+	return
+}
+
+func UnmarshalECHKeys(raw []byte) ([]tlsC.EncryptedClientHelloKey, error) {
+	var keys []tlsC.EncryptedClientHelloKey
+	rawString := cryptobyte.String(raw)
+	for !rawString.Empty() {
+		var key tlsC.EncryptedClientHelloKey
+		if !rawString.ReadUint16LengthPrefixed((*cryptobyte.String)(&key.PrivateKey)) {
+			return nil, errors.New("error parsing private key")
+		}
+		if !rawString.ReadUint16LengthPrefixed((*cryptobyte.String)(&key.Config)) {
+			return nil, errors.New("error parsing config")
+		}
+		keys = append(keys, key)
+	}
+	if len(keys) == 0 {
+		return nil, errors.New("empty ECH keys")
+	}
+	return keys, nil
+}
+
+func LoadECHKey(key string, tlsConfig *tlsC.Config, path ca.Path) error {
+	if key == "" {
+		return nil
+	}
+	painTextErr := loadECHKey([]byte(key), tlsConfig)
+	if painTextErr == nil {
+		return nil
+	}
+	key = path.Resolve(key)
+	var loadErr error
+	if !path.IsSafePath(key) {
+		loadErr = path.ErrNotSafePath(key)
+	} else {
+		var echKey []byte
+		echKey, loadErr = os.ReadFile(key)
+		if loadErr == nil {
+			loadErr = loadECHKey(echKey, tlsConfig)
+		}
+	}
+	if loadErr != nil {
+		return fmt.Errorf("parse ECH keys failed, maybe format error:%s, or path error: %s", painTextErr.Error(), loadErr.Error())
+	}
+	return nil
+}
+
+func loadECHKey(echKey []byte, tlsConfig *tlsC.Config) error {
+	block, rest := pem.Decode(echKey)
+	if block == nil || block.Type != "ECH KEYS" || len(rest) > 0 {
+		return errors.New("invalid ECH keys pem")
+	}
+	echKeys, err := UnmarshalECHKeys(block.Bytes)
+	if err != nil {
+		return fmt.Errorf("parse ECH keys: %w", err)
+	}
+	tlsConfig.EncryptedClientHelloKeys = echKeys
+	return nil
+}

component/generater/cmd.go

@@ -4,12 +4,14 @@ import (
 	"encoding/base64"
 	"fmt"
 
+	"github.com/metacubex/mihomo/component/ech"
+
 	"github.com/gofrs/uuid/v5"
 )
 
 func Main(args []string) {
 	if len(args) < 1 {
-		panic("Using: generate uuid/reality-keypair/wg-keypair")
+		panic("Using: generate uuid/reality-keypair/wg-keypair/ech-keypair")
 	}
 	switch args[0] {
 	case "uuid":
@@ -33,5 +35,15 @@ func Main(args []string) {
 		}
 		fmt.Println("PrivateKey: " + privateKey.String())
 		fmt.Println("PublicKey: " + privateKey.PublicKey().String())
+	case "ech-keypair":
+		if len(args) < 2 {
+			panic("Using: generate ech-keypair <plain_server_name>")
+		}
+		configBase64, keyPem, err := ech.GenECHConfig(args[1])
+		if err != nil {
+			panic(err)
+		}
+		fmt.Println("Config:", configBase64)
+		fmt.Println("Key:", keyPem)
 	}
 }

component/tls/utls.go

@@ -26,6 +26,10 @@ func UClient(c net.Conn, config *utls.Config, fingerprint UClientHelloID) *UConn
 	return utls.UClient(c, config, fingerprint)
 }
 
+func NewListener(inner net.Listener, config *Config) net.Listener {
+	return utls.NewListener(inner, config)
+}
+
 func GetFingerprint(clientFingerprint string) (UClientHelloID, bool) {
 	if len(clientFingerprint) == 0 {
 		clientFingerprint = globalFingerprint
@@ -93,7 +97,9 @@ func init() {
 	fingerprints["randomized"] = randomized
 }
 
-func UCertificates(it tls.Certificate) utls.Certificate {
+type Certificate = utls.Certificate
+
+func UCertificate(it tls.Certificate) utls.Certificate {
 	return utls.Certificate{
 		Certificate: it.Certificate,
 		PrivateKey:  it.PrivateKey,
@@ -106,13 +112,15 @@ func UCertificates(it tls.Certificate) utls.Certificate {
 	}
 }
 
+type EncryptedClientHelloKey = utls.EncryptedClientHelloKey
+
 type Config = utls.Config
 
 func UConfig(config *tls.Config) *utls.Config {
 	return &utls.Config{
 		Rand:                  config.Rand,
 		Time:                  config.Time,
-		Certificates:          utils.Map(config.Certificates, UCertificates),
+		Certificates:          utils.Map(config.Certificates, UCertificate),
 		VerifyPeerCertificate: config.VerifyPeerCertificate,
 		RootCAs:               config.RootCAs,
 		NextProtos:            config.NextProtos,