470 lines
14 KiB
Go
470 lines
14 KiB
Go
package tor
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import (
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"context"
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"fmt"
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"io"
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"io/ioutil"
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"net/textproto"
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"os"
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"path/filepath"
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"strconv"
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"time"
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"git.openprivacy.ca/openprivacy/bine/control"
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"git.openprivacy.ca/openprivacy/bine/process"
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)
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// Tor is the wrapper around the Tor process and control port connection. It
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// should be created with Start and developers should always call Close when
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// done.
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type Tor struct {
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// Process is the Tor instance that is running.
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Process process.Process
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// Control is the Tor controller connection.
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Control *control.Conn
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// ProcessCancelFunc is the context cancellation func for the Tor process.
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// It is used by Close and should not be called directly. This can be nil.
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ProcessCancelFunc context.CancelFunc
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// ControlPort is the port that Control is connected on. It is 0 if the
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// connection is an embedded control connection.
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ControlPort int
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// DataDir is the path to the data directory that Tor is using.
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DataDir string
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// DeleteDataDirOnClose is true if, when Close is invoked, the entire
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// directory will be deleted.
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DeleteDataDirOnClose bool
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// DebugWriter is the writer used for debug logs, or nil if debug logs
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// should not be emitted.
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DebugWriter io.Writer
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// StopProcessOnClose, if true, will attempt to halt the process on close.
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StopProcessOnClose bool
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// GeoIPCreatedFile is the path, relative to DataDir, that was created from
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// StartConf.GeoIPFileReader. It is empty if no file was created.
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GeoIPCreatedFile string
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// GeoIPv6CreatedFile is the path, relative to DataDir, that was created
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// from StartConf.GeoIPFileReader. It is empty if no file was created.
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GeoIPv6CreatedFile string
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}
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// StartConf is the configuration used for Start when starting a Tor instance. A
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// default instance with no fields set is the default used for Start.
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type StartConf struct {
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// ExePath is the path to the Tor executable. If it is not present, "tor" is
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// used either locally or on the PATH. This is ignored if ProcessCreator is
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// set.
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ExePath string
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// ProcessCreator is the override to use a specific process creator. If set,
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// ExePath is ignored.
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ProcessCreator process.Creator
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// UseEmbeddedControlConn can be set to true to use
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// process.Process.EmbeddedControlConn() instead of creating a connection
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// via ControlPort. Note, this only works when ProcessCreator is an
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// embedded Tor creator with version >= 0.3.5.x.
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UseEmbeddedControlConn bool
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// ControlPort is the port to use for the Tor controller. If it is 0, Tor
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// picks a port for use. This is ignored if UseEmbeddedControlConn is true.
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ControlPort int
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// DataDir is the directory used by Tor. If it is empty, a temporary
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// directory is created in TempDataDirBase.
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DataDir string
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// TempDataDirBase is the parent directory that a temporary data directory
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// will be created under for use by Tor. This is ignored if DataDir is not
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// empty. If empty it is assumed to be the current working directory.
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TempDataDirBase string
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// RetainTempDataDir, if true, will not set the created temporary data
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// directory to be deleted on close. This is ignored if DataDir is not
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// empty.
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RetainTempDataDir bool
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// DisableCookieAuth, if true, will not use the default SAFECOOKIE
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// authentication mechanism for the Tor controller.
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DisableCookieAuth bool
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// DisableEagerAuth, if true, will not authenticate on Start.
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DisableEagerAuth bool
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// EnableNetwork, if true, will connect to the wider Tor network on start.
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EnableNetwork bool
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// ExtraArgs is the set of extra args passed to the Tor instance when
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// started.
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ExtraArgs []string
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// TorrcFile is the torrc file to set on start. If empty, a blank torrc is
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// created in the data directory and is used instead.
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TorrcFile string
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// DebugWriter is the writer to use for debug logs, or nil for no debug
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// logs.
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DebugWriter io.Writer
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// NoHush if true does not set --hush. By default --hush is set.
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NoHush bool
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// NoAutoSocksPort if true does not set "--SocksPort auto" as is done by
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// default. This means the caller could set their own or just let it
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// default to 9050.
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NoAutoSocksPort bool
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// GeoIPReader, if present, is called before start to copy geo IP files to
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// the data directory. Errors are propagated. If the ReadCloser is present,
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// it is copied to the data dir, overwriting as necessary, and then closed
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// and the appropriate command line argument is added to reference it. If
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// both the ReadCloser and error are nil, no copy or command line argument
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// is used for that version. This is called twice, once with false and once
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// with true for ipv6.
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//
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// This can be set to torutil/geoipembed.GeoIPReader to use an embedded
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// source.
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GeoIPFileReader func(ipv6 bool) (io.ReadCloser, error)
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}
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// Start a Tor instance and connect to it. If ctx is nil, context.Background()
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// is used. If conf is nil, a default instance is used.
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func Start(ctx context.Context, conf *StartConf) (*Tor, error) {
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if ctx == nil {
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ctx = context.Background()
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}
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if conf == nil {
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conf = &StartConf{}
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}
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tor := &Tor{DataDir: conf.DataDir, DebugWriter: conf.DebugWriter, StopProcessOnClose: true}
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// Create the data dir and make it absolute
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if tor.DataDir == "" {
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tempBase := conf.TempDataDirBase
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if tempBase == "" {
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tempBase = "."
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}
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var err error
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if tempBase, err = filepath.Abs(tempBase); err != nil {
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return nil, err
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}
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if tor.DataDir, err = ioutil.TempDir(tempBase, "data-dir-"); err != nil {
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return nil, fmt.Errorf("Unable to create temp data dir: %v", err)
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}
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tor.Debugf("Created temp data directory at: %v", tor.DataDir)
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tor.DeleteDataDirOnClose = !conf.RetainTempDataDir
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} else if err := os.MkdirAll(tor.DataDir, 0700); err != nil {
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return nil, fmt.Errorf("Unable to create data dir: %v", err)
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}
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// !!!! From this point on, we must close tor if we error !!!!
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// Copy geoip stuff if necessary
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err := tor.copyGeoIPFiles(conf)
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// Start tor
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if err == nil {
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err = tor.startProcess(ctx, conf)
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}
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// Connect the controller
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if err == nil {
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for attempts := 0; attempts < 10; attempts++ {
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err = tor.connectController(ctx, conf)
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if err == nil {
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break
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} else {
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// backoff and retry
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// max is 1 + 2 + 3 + 4 + 5...+10 = ~55 seconds
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// After which point there is probably something else very wrong
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// TODO: It might be worth breaking out the error here so that we can distinguish a
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// slow socket (on e.g. Android) with a failed setup.
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time.Sleep(time.Duration(int(time.Second) * attempts))
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}
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}
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}
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// Attempt eager auth w/ no password
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if err == nil && !conf.DisableEagerAuth {
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err = tor.Control.Authenticate("")
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}
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// If there was an error, we have to try to close here but it may leave the process open
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if err != nil {
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if closeErr := tor.Close(); closeErr != nil {
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err = fmt.Errorf("Error on start: %v (also got error trying to close: %v)", err, closeErr)
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}
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}
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return tor, err
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}
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func (t *Tor) copyGeoIPFiles(conf *StartConf) error {
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if conf.GeoIPFileReader == nil {
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return nil
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}
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if r, err := conf.GeoIPFileReader(false); err != nil {
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return fmt.Errorf("Unable to read geoip file: %v", err)
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} else if r != nil {
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t.GeoIPCreatedFile = "geoip"
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if err := createFile(filepath.Join(t.DataDir, "geoip"), r); err != nil {
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return fmt.Errorf("Unable to create geoip file: %v", err)
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}
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}
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if r, err := conf.GeoIPFileReader(true); err != nil {
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return fmt.Errorf("Unable to read geoip6 file: %v", err)
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} else if r != nil {
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t.GeoIPv6CreatedFile = "geoip6"
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if err := createFile(filepath.Join(t.DataDir, "geoip6"), r); err != nil {
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return fmt.Errorf("Unable to create geoip6 file: %v", err)
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}
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}
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return nil
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}
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func createFile(to string, from io.ReadCloser) error {
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f, err := os.Create(to)
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if err == nil {
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_, err = io.Copy(f, from)
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if closeErr := f.Close(); err == nil {
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err = closeErr
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}
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}
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if closeErr := from.Close(); err == nil {
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err = closeErr
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}
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return err
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}
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func (t *Tor) startProcess(ctx context.Context, conf *StartConf) error {
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// Get the creator
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creator := conf.ProcessCreator
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if creator == nil {
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torPath := conf.ExePath
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if torPath == "" {
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torPath = "tor"
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}
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creator = process.NewCreator(torPath)
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}
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// Build the args
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args := []string{"--DataDirectory", t.DataDir}
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if !conf.DisableCookieAuth {
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args = append(args, "--CookieAuthentication", "1")
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}
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if !conf.EnableNetwork {
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args = append(args, "--DisableNetwork", "1")
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}
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if !conf.NoHush {
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args = append(args, "--hush")
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}
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if !conf.NoAutoSocksPort {
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args = append(args, "--SocksPort", "auto")
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}
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if t.GeoIPCreatedFile != "" {
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args = append(args, "--GeoIPFile", filepath.Join(t.DataDir, t.GeoIPCreatedFile))
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}
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if t.GeoIPv6CreatedFile != "" {
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args = append(args, "--GeoIPv6File", filepath.Join(t.DataDir, t.GeoIPv6CreatedFile))
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}
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// If there is no Torrc file, create a blank temp one
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torrcFileName := conf.TorrcFile
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if torrcFileName == "" {
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torrcFile, err := ioutil.TempFile(t.DataDir, "torrc-")
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if err != nil {
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return err
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}
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torrcFileName = torrcFile.Name()
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if err = torrcFile.Close(); err != nil {
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return err
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}
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}
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args = append(args, "-f", torrcFileName)
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// Create file for Tor to write the control port to if it's not told to us and we're not embedded
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var controlPortFileName string
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var err error
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if !conf.UseEmbeddedControlConn {
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if conf.ControlPort == 0 {
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controlPortFile, err := ioutil.TempFile(t.DataDir, "control-port-")
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if err != nil {
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return err
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}
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controlPortFileName = controlPortFile.Name()
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if err = controlPortFile.Close(); err != nil {
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return err
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}
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args = append(args, "--ControlPort", "auto", "--ControlPortWriteToFile", controlPortFile.Name())
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} else {
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args = append(args, "--ControlPort", strconv.Itoa(conf.ControlPort))
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}
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}
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// Create process creator with args
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var processCtx context.Context
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processCtx, t.ProcessCancelFunc = context.WithCancel(ctx)
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args = append(args, conf.ExtraArgs...)
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p, err := creator.New(processCtx, args...)
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if err != nil {
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return err
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}
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// Use the embedded conn if requested
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if conf.UseEmbeddedControlConn {
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t.Debugf("Using embedded control connection")
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conn, err := p.EmbeddedControlConn()
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if err != nil {
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return fmt.Errorf("Unable to get embedded control conn: %v", err)
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}
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t.Control = control.NewConn(textproto.NewConn(conn))
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t.Control.DebugWriter = t.DebugWriter
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}
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// Start process with the args
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t.Debugf("Starting tor with args %v", args)
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if err = p.Start(); err != nil {
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return err
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}
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t.Process = p
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// If not embedded, try a few times to read the control port file if we need to
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if !conf.UseEmbeddedControlConn {
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t.ControlPort = conf.ControlPort
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if t.ControlPort == 0 {
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ControlPortCheck:
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for i := 0; i < 10; i++ {
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select {
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case <-ctx.Done():
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err = ctx.Err()
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break ControlPortCheck
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default:
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// Try to read the controlport file, or wait a bit
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var byts []byte
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if byts, err = ioutil.ReadFile(controlPortFileName); err != nil {
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break ControlPortCheck
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} else if t.ControlPort, err = process.ControlPortFromFileContents(string(byts)); err == nil {
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break ControlPortCheck
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}
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time.Sleep(200 * time.Millisecond)
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}
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}
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if err != nil {
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return fmt.Errorf("Unable to read control port file: %v", err)
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}
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}
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}
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return nil
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}
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func (t *Tor) connectController(ctx context.Context, conf *StartConf) error {
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// This doesn't apply if already connected (e.g. using embedded conn)
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if t.Control != nil {
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return nil
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}
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t.Debugf("Connecting to control port %v", t.ControlPort)
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textConn, err := textproto.Dial("tcp", "127.0.0.1:"+strconv.Itoa(t.ControlPort))
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if err != nil {
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return err
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}
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t.Control = control.NewConn(textConn)
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t.Control.DebugWriter = t.DebugWriter
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return nil
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}
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// EnableNetwork sets DisableNetwork to 0 and optionally waits for bootstrap to
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// complete. The context can be nil. If DisableNetwork isnt 1, this does
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// nothing.
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func (t *Tor) EnableNetwork(ctx context.Context, wait bool) error {
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if ctx == nil {
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ctx = context.Background()
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}
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// Only enable if DisableNetwork is 1
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if vals, err := t.Control.GetConf("DisableNetwork"); err != nil {
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return err
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} else if len(vals) == 0 || vals[0].Key != "DisableNetwork" || vals[0].Val != "1" {
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return nil
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}
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// Enable the network
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if err := t.Control.SetConf(control.KeyVals("DisableNetwork", "0")...); err != nil {
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return nil
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}
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// If not waiting, leave
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if !wait {
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return nil
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}
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// Wait for progress to hit 100
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_, err := t.Control.EventWait(ctx, []control.EventCode{control.EventCodeStatusClient},
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func(evt control.Event) (bool, error) {
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if status, _ := evt.(*control.StatusEvent); status != nil && status.Action == "BOOTSTRAP" {
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if status.Severity == "NOTICE" && status.Arguments["PROGRESS"] == "100" {
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return true, nil
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} else if status.Severity == "ERR" {
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return false, fmt.Errorf("Failing bootstrapping, Tor warning: %v", status.Arguments["WARNING"])
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}
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}
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return false, nil
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})
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return err
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}
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// Close sends a halt to the Tor process if it can, closes the controller
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// connection, and stops the process.
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func (t *Tor) Close() error {
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t.Debugf("Closing Tor")
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errs := []error{}
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// If controller is authenticated, send the quit signal to the process. Otherwise, just close the controller.
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sentHalt := false
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if t.Control != nil {
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if t.Control.Authenticated && t.StopProcessOnClose {
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if err := t.Control.Signal("HALT"); err != nil {
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errs = append(errs, fmt.Errorf("Unable to signal halt: %v", err))
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} else {
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sentHalt = true
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}
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}
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// Now close the controller
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if err := t.Control.Close(); err != nil {
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errs = append(errs, fmt.Errorf("Unable to close contrlller: %v", err))
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} else {
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t.Control = nil
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}
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}
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if t.Process != nil {
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// If we didn't halt, we have to force kill w/ the cancel func
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if !sentHalt && t.StopProcessOnClose {
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t.ProcessCancelFunc()
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}
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// Wait for a bit to make sure it stopped
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errCh := make(chan error, 1)
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var waitErr error
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go func() { errCh <- t.Process.Wait() }()
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select {
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case waitErr = <-errCh:
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if waitErr != nil {
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errs = append(errs, fmt.Errorf("Process wait failed: %v", waitErr))
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}
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case <-time.After(300 * time.Millisecond):
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errs = append(errs, fmt.Errorf("Process did not exit after 300 ms"))
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}
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if waitErr == nil {
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t.Process = nil
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}
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}
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// Get rid of the entire data dir
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if t.DeleteDataDirOnClose {
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if err := os.RemoveAll(t.DataDir); err != nil {
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errs = append(errs, fmt.Errorf("Failed to remove data dir %v: %v", t.DataDir, err))
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}
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}
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// Combine the errors if present
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if len(errs) == 0 {
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return nil
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} else if len(errs) == 1 {
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t.Debugf("Error while closing Tor: %v", errs[0])
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return errs[0]
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}
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t.Debugf("Errors while closing Tor: %v", errs)
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return fmt.Errorf("Got %v errors while closing - %v", len(errs), errs)
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}
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