lnd.xprv/tor/add_onion.go

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package tor
import (
"errors"
"fmt"
"io/ioutil"
"os"
)
var (
// ErrNoPrivateKey is an error returned by the OnionStore.PrivateKey
// method when a private key hasn't yet been stored.
ErrNoPrivateKey = errors.New("private key not found")
)
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// OnionType denotes the type of the onion service.
type OnionType int
const (
// V2 denotes that the onion service is V2.
V2 OnionType = iota
// V3 denotes that the onion service is V3.
V3
)
// OnionStore is a store containing information about a particular onion
// service.
type OnionStore interface {
// StorePrivateKey stores the private key according to the
// implementation of the OnionStore interface.
StorePrivateKey(OnionType, []byte) error
// PrivateKey retrieves a stored private key. If it is not found, then
// ErrNoPrivateKey should be returned.
PrivateKey(OnionType) ([]byte, error)
// DeletePrivateKey securely removes the private key from the store.
DeletePrivateKey(OnionType) error
}
// OnionFile is a file-based implementation of the OnionStore interface that
// stores an onion service's private key.
type OnionFile struct {
privateKeyPath string
privateKeyPerm os.FileMode
}
// A compile-time constraint to ensure OnionFile satisfies the OnionStore
// interface.
var _ OnionStore = (*OnionFile)(nil)
// NewOnionFile creates a file-based implementation of the OnionStore interface
// to store an onion service's private key.
func NewOnionFile(privateKeyPath string, privateKeyPerm os.FileMode) *OnionFile {
return &OnionFile{
privateKeyPath: privateKeyPath,
privateKeyPerm: privateKeyPerm,
}
}
// StorePrivateKey stores the private key at its expected path.
func (f *OnionFile) StorePrivateKey(_ OnionType, privateKey []byte) error {
return ioutil.WriteFile(f.privateKeyPath, privateKey, f.privateKeyPerm)
}
// PrivateKey retrieves the private key from its expected path. If the file does
// not exist, then ErrNoPrivateKey is returned.
func (f *OnionFile) PrivateKey(_ OnionType) ([]byte, error) {
if _, err := os.Stat(f.privateKeyPath); os.IsNotExist(err) {
return nil, ErrNoPrivateKey
}
return ioutil.ReadFile(f.privateKeyPath)
}
// DeletePrivateKey removes the file containing the private key.
func (f *OnionFile) DeletePrivateKey(_ OnionType) error {
return os.Remove(f.privateKeyPath)
}
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// AddOnionConfig houses all of the required parameters in order to successfully
// create a new onion service or restore an existing one.
type AddOnionConfig struct {
// Type denotes the type of the onion service that should be created.
Type OnionType
// VirtualPort is the externally reachable port of the onion address.
VirtualPort int
// TargetPorts is the set of ports that the service will be listening on
// locally. The Tor server will use choose a random port from this set
// to forward the traffic from the virtual port.
//
// NOTE: If nil/empty, the virtual port will be used as the only target
// port.
TargetPorts []int
// Store is responsible for storing all onion service related
// information.
//
// NOTE: If not specified, then nothing will be stored, making onion
// services unrecoverable after shutdown.
Store OnionStore
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}
// AddOnion creates an onion service and returns its onion address. Once
// created, the new onion service will remain active until the connection
// between the controller and the Tor server is closed.
func (c *Controller) AddOnion(cfg AddOnionConfig) (*OnionAddr, error) {
// Before sending the request to create an onion service to the Tor
// server, we'll make sure that it supports V3 onion services if that
// was the type requested.
if cfg.Type == V3 {
if err := supportsV3(c.version); err != nil {
return nil, err
}
}
// We'll start off by checking if the store contains an existing private
// key. If it does not, then we should request the server to create a
// new onion service and return its private key. Otherwise, we'll
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// request the server to recreate the onion server from our private key.
var keyParam string
switch cfg.Type {
case V2:
keyParam = "NEW:RSA1024"
case V3:
keyParam = "NEW:ED25519-V3"
}
if cfg.Store != nil {
privateKey, err := cfg.Store.PrivateKey(cfg.Type)
switch err {
// Proceed to request a new onion service.
case ErrNoPrivateKey:
// Recover the onion service with the private key found.
case nil:
keyParam = string(privateKey)
default:
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return nil, err
}
}
// Now, we'll create a mapping from the virtual port to each target
// port. If no target ports were specified, we'll use the virtual port
// to provide a one-to-one mapping.
var portParam string
// Helper function which appends the correct Port param depending on
// whether the user chose to use a custom target IP address or not.
pushPortParam := func(targetPort int) {
if c.targetIPAddress == "" {
portParam += fmt.Sprintf("Port=%d,%d ", cfg.VirtualPort,
targetPort)
} else {
portParam += fmt.Sprintf("Port=%d,%s:%d ", cfg.VirtualPort,
c.targetIPAddress, targetPort)
}
}
if len(cfg.TargetPorts) == 0 {
pushPortParam(cfg.VirtualPort)
} else {
for _, targetPort := range cfg.TargetPorts {
pushPortParam(targetPort)
}
}
// Send the command to create the onion service to the Tor server and
// await its response.
cmd := fmt.Sprintf("ADD_ONION %s %s", keyParam, portParam)
_, reply, err := c.sendCommand(cmd)
if err != nil {
return nil, err
}
// If successful, the reply from the server should be of the following
// format, depending on whether a private key has been requested:
//
// C: ADD_ONION RSA1024:[Blob Redacted] Port=80,8080
// S: 250-ServiceID=testonion1234567
// S: 250 OK
//
// C: ADD_ONION NEW:RSA1024 Port=80,8080
// S: 250-ServiceID=testonion1234567
// S: 250-PrivateKey=RSA1024:[Blob Redacted]
// S: 250 OK
//
// We're interested in retrieving the service ID, which is the public
// name of the service, and the private key if requested.
replyParams := parseTorReply(reply)
serviceID, ok := replyParams["ServiceID"]
if !ok {
return nil, errors.New("service id not found in reply")
}
// If a new onion service was created and an onion store was provided,
// we'll store its private key to disk in the event that it needs to be
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// recreated later on.
if privateKey, ok := replyParams["PrivateKey"]; cfg.Store != nil && ok {
err := cfg.Store.StorePrivateKey(cfg.Type, []byte(privateKey))
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if err != nil {
return nil, fmt.Errorf("unable to write private key "+
"to file: %v", err)
}
}
// Finally, we'll return the onion address composed of the service ID,
// along with the onion suffix, and the port this onion service can be
// reached at externally.
return &OnionAddr{
OnionService: serviceID + ".onion",
Port: cfg.VirtualPort,
}, nil
}