AUTH-2394 added socks5 proxy

socks/authenticator.go

@@ -0,0 +1,87 @@
+package socks
+
+import (
+	"fmt"
+	"io"
+)
+
+// Authenticator is the connection passed in as a reader/writer to support different authentication types
+type Authenticator interface {
+	Handle(io.Reader, io.Writer) error
+}
+
+// NoAuthAuthenticator is used to handle the No Authentication mode
+type NoAuthAuthenticator struct{}
+
+// NewNoAuthAuthenticator creates a authless Authenticator
+func NewNoAuthAuthenticator() Authenticator {
+	return &NoAuthAuthenticator{}
+}
+
+// Handle writes back the version and NoAuth
+func (a *NoAuthAuthenticator) Handle(reader io.Reader, writer io.Writer) error {
+	_, err := writer.Write([]byte{socks5Version, NoAuth})
+	return err
+}
+
+// UserPassAuthAuthenticator is used to handle the user/password mode
+type UserPassAuthAuthenticator struct {
+	IsValid func(string, string) bool
+}
+
+// NewUserPassAuthAuthenticator creates a new username/password validator Authenticator
+func NewUserPassAuthAuthenticator(isValid func(string, string) bool) Authenticator {
+	return &UserPassAuthAuthenticator{
+		IsValid: isValid,
+	}
+}
+
+// Handle writes back the version and NoAuth
+func (a *UserPassAuthAuthenticator) Handle(reader io.Reader, writer io.Writer) error {
+	if _, err := writer.Write([]byte{socks5Version, UserPassAuth}); err != nil {
+		return err
+	}
+
+	// Get the version and username length
+	header := []byte{0, 0}
+	if _, err := io.ReadAtLeast(reader, header, 2); err != nil {
+		return err
+	}
+
+	// Ensure compatibility. Someone call E-harmony
+	if header[0] != userAuthVersion {
+		return fmt.Errorf("Unsupported auth version: %v", header[0])
+	}
+
+	// Get the user name
+	userLen := int(header[1])
+	user := make([]byte, userLen)
+	if _, err := io.ReadAtLeast(reader, user, userLen); err != nil {
+		return err
+	}
+
+	// Get the password length
+	if _, err := reader.Read(header[:1]); err != nil {
+		return err
+	}
+
+	// Get the password
+	passLen := int(header[0])
+	pass := make([]byte, passLen)
+	if _, err := io.ReadAtLeast(reader, pass, passLen); err != nil {
+		return err
+	}
+
+	// Verify the password
+	if a.IsValid(string(user), string(pass)) {
+		_, err := writer.Write([]byte{userAuthVersion, authSuccess})
+		return err
+	}
+
+	// password failed. Write back failure
+	if _, err := writer.Write([]byte{userAuthVersion, authFailure}); err != nil {
+		return err
+	}
+
+	return fmt.Errorf("User authentication failed")
+}