package pgconn import ( "errors" "fmt" "github.com/jackc/pgx/v5/pgproto3" ) // NewGSSFunc creates a GSS authentication provider, for use with // RegisterGSSProvider. type NewGSSFunc func() (GSS, error) var newGSS NewGSSFunc // RegisterGSSProvider registers a GSS authentication provider. For example, if // you need to use Kerberos to authenticate with your server, add this to your // main package: // // import "github.com/otan/gopgkrb5" // // func init() { // pgconn.RegisterGSSProvider(func() (pgconn.GSS, error) { return gopgkrb5.NewGSS() }) // } func RegisterGSSProvider(newGSSArg NewGSSFunc) { newGSS = newGSSArg } // GSS provides GSSAPI authentication (e.g., Kerberos). type GSS interface { GetInitToken(host string, service string) ([]byte, error) GetInitTokenFromSPN(spn string) ([]byte, error) Continue(inToken []byte) (done bool, outToken []byte, err error) } func (c *PgConn) gssAuth() error { if newGSS == nil { return errors.New("kerberos error: no GSSAPI provider registered, see https://github.com/otan/gopgkrb5") } cli, err := newGSS() if err != nil { return err } var nextData []byte if c.config.KerberosSpn != "" { // Use the supplied SPN if provided. nextData, err = cli.GetInitTokenFromSPN(c.config.KerberosSpn) } else { // Allow the kerberos service name to be overridden service := "postgres" if c.config.KerberosSrvName != "" { service = c.config.KerberosSrvName } nextData, err = cli.GetInitToken(c.config.Host, service) } if err != nil { return err } for { gssResponse := &pgproto3.GSSResponse{ Data: nextData, } c.frontend.Send(gssResponse) err = c.frontend.Flush() if err != nil { return err } resp, err := c.rxGSSContinue() if err != nil { return err } var done bool done, nextData, err = cli.Continue(resp.Data) if err != nil { return err } if done { break } } return nil } func (c *PgConn) rxGSSContinue() (*pgproto3.AuthenticationGSSContinue, error) { msg, err := c.receiveMessage() if err != nil { return nil, err } switch m := msg.(type) { case *pgproto3.AuthenticationGSSContinue: return m, nil case *pgproto3.ErrorResponse: return nil, ErrorResponseToPgError(m) } return nil, fmt.Errorf("expected AuthenticationGSSContinue message but received unexpected message %T", msg) }