From abe3dc6039b11319414e352be4424ec20001a418 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E4=B8=96=E7=95=8C?= <i@sekai.icu>
Date: Fri, 23 Sep 2022 17:13:18 +0800
Subject: [PATCH] Add self sign cert support

---
 common/tls/mkcert.go     | 50 ++++++++++++++++++++++++++++++++++++++++
 common/tls/std_server.go | 31 +++++++++++++++++--------
 option/tls.go            |  1 +
 3 files changed, 72 insertions(+), 10 deletions(-)
 create mode 100644 common/tls/mkcert.go

diff --git a/common/tls/mkcert.go b/common/tls/mkcert.go
new file mode 100644
index 00000000..d11ca934
--- /dev/null
+++ b/common/tls/mkcert.go
@@ -0,0 +1,50 @@
+package tls
+
+import (
+	"crypto/rand"
+	"crypto/rsa"
+	"crypto/tls"
+	"crypto/x509"
+	"crypto/x509/pkix"
+	"encoding/pem"
+	"math/big"
+	"time"
+)
+
+func GenerateKeyPair(serverName string) (*tls.Certificate, error) {
+	key, err := rsa.GenerateKey(rand.Reader, 2048)
+	if err != nil {
+		return nil, err
+	}
+	serialNumber, err := rand.Int(rand.Reader, new(big.Int).Lsh(big.NewInt(1), 128))
+	if err != nil {
+		return nil, err
+	}
+	template := &x509.Certificate{
+		SerialNumber:          serialNumber,
+		NotBefore:             time.Now().Add(time.Hour * -1),
+		NotAfter:              time.Now().Add(time.Hour),
+		KeyUsage:              x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
+		ExtKeyUsage:           []x509.ExtKeyUsage{x509.ExtKeyUsageServerAuth},
+		BasicConstraintsValid: true,
+		Subject: pkix.Name{
+			CommonName: serverName,
+		},
+		DNSNames: []string{serverName},
+	}
+	publicDer, err := x509.CreateCertificate(rand.Reader, template, template, key.Public(), key)
+	if err != nil {
+		return nil, err
+	}
+	privateDer, err := x509.MarshalPKCS8PrivateKey(key)
+	if err != nil {
+		return nil, err
+	}
+	publicPem := pem.EncodeToMemory(&pem.Block{Type: "CERTIFICATE", Bytes: publicDer})
+	privPem := pem.EncodeToMemory(&pem.Block{Type: "PRIVATE KEY", Bytes: privateDer})
+	keyPair, err := tls.X509KeyPair(publicPem, privPem)
+	if err != nil {
+		return nil, err
+	}
+	return &keyPair, err
+}
diff --git a/common/tls/std_server.go b/common/tls/std_server.go
index 22f1924f..b95101a6 100644
--- a/common/tls/std_server.go
+++ b/common/tls/std_server.go
@@ -34,6 +34,8 @@ func (c *STDServerConfig) SetNextProtos(nextProto []string) {
 	c.config.NextProtos = nextProto
 }
 
+var errInsecureUnused = E.New("tls: insecure unused")
+
 func newSTDServer(ctx context.Context, logger log.Logger, options option.InboundTLSOptions) (ServerConfig, error) {
 	if !options.Enabled {
 		return nil, nil
@@ -46,6 +48,9 @@ func newSTDServer(ctx context.Context, logger log.Logger, options option.Inbound
 		if err != nil {
 			return nil, err
 		}
+		if options.Insecure {
+			return nil, errInsecureUnused
+		}
 	} else {
 		tlsConfig = &tls.Config{}
 	}
@@ -102,17 +107,23 @@ func newSTDServer(ctx context.Context, logger log.Logger, options option.Inbound
 			}
 			key = content
 		}
-		if certificate == nil {
-			return nil, E.New("missing certificate")
+		if certificate == nil && key == nil && options.Insecure {
+			tlsConfig.GetCertificate = func(info *tls.ClientHelloInfo) (*tls.Certificate, error) {
+				return GenerateKeyPair(info.ServerName)
+			}
+		} else {
+			if certificate == nil {
+				return nil, E.New("missing certificate")
+			} else if key == nil {
+				return nil, E.New("missing key")
+			}
+
+			keyPair, err := tls.X509KeyPair(certificate, key)
+			if err != nil {
+				return nil, E.Cause(err, "parse x509 key pair")
+			}
+			tlsConfig.Certificates = []tls.Certificate{keyPair}
 		}
-		if key == nil {
-			return nil, E.New("missing key")
-		}
-		keyPair, err := tls.X509KeyPair(certificate, key)
-		if err != nil {
-			return nil, E.Cause(err, "parse x509 key pair")
-		}
-		tlsConfig.Certificates = []tls.Certificate{keyPair}
 	}
 	return &STDServerConfig{
 		config:          tlsConfig,
diff --git a/option/tls.go b/option/tls.go
index 33b5d8d1..72a74966 100644
--- a/option/tls.go
+++ b/option/tls.go
@@ -3,6 +3,7 @@ package option
 type InboundTLSOptions struct {
 	Enabled         bool                `json:"enabled,omitempty"`
 	ServerName      string              `json:"server_name,omitempty"`
+	Insecure        bool                `json:"insecure,omitempty"`
 	ALPN            Listable[string]    `json:"alpn,omitempty"`
 	MinVersion      string              `json:"min_version,omitempty"`
 	MaxVersion      string              `json:"max_version,omitempty"`