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