forked from openprivacy/connectivity
80 lines
2.6 KiB
Go
80 lines
2.6 KiB
Go
package tor
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import (
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"encoding/base32"
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"errors"
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"git.openprivacy.ca/openprivacy/bine/control"
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"git.openprivacy.ca/openprivacy/bine/tor"
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"golang.org/x/crypto/ed25519"
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"golang.org/x/crypto/sha3"
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"strings"
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)
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// V3HostnameLength is the length of a Tor V3 Onion Address (without the .onion suffix)
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const V3HostnameLength = 56
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// Hidden service version
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const version = byte(0x03)
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// Salt used to create checkdigits
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const salt = ".onion checksum"
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func getCheckdigits(pub ed25519.PublicKey) []byte {
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// Calculate checksum sha3(".onion checksum" || publicKey || version)
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checkstr := []byte(salt)
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checkstr = append(checkstr, pub...)
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checkstr = append(checkstr, version)
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checksum := sha3.Sum256(checkstr)
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return checksum[:2]
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}
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// GetTorV3Hostname converts an ed25519 public key to a valid tor onion hostname
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func GetTorV3Hostname(pub ed25519.PublicKey) string {
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// Construct onion address base32(publicKey || checkdigits || version)
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checkdigits := getCheckdigits(pub)
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combined := pub[:]
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combined = append(combined, checkdigits...)
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combined = append(combined, version)
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serviceID := base32.StdEncoding.EncodeToString(combined)
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return strings.ToLower(serviceID)
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}
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// IsValidHostname returns true if the given address is a valid onion v3 address
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func IsValidHostname(address string) bool {
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if len(address) == V3HostnameLength {
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data, err := base32.StdEncoding.DecodeString(strings.ToUpper(address))
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if err == nil {
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pubkey := data[0:ed25519.PublicKeySize]
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if GetTorV3Hostname(ed25519.PublicKey(pubkey)) == address {
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return true
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}
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}
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}
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return false
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}
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// HashedPasswordAuthenticator authenticates to a Tor control port using a hashed password.
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// Note: This method is vulnerable to replay attacks by the host system (but so is cookie auth)
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type HashedPasswordAuthenticator struct {
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Password string
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}
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// Authenticate uses the given hashed password to authenticate to the control port
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func (h HashedPasswordAuthenticator) Authenticate(controlport *control.Conn) error {
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return controlport.Authenticate(h.Password)
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}
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// NewHashedPasswordAuthenticator creates a new hashed password authenticator
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func NewHashedPasswordAuthenticator(password string) tor.Authenticator {
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return HashedPasswordAuthenticator{Password: password}
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}
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// NullAuthenticator exists to force always authenticating to a system tor.
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type NullAuthenticator struct {
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}
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// Authenticate on a NullAuthenticator always results in failure.
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func (n NullAuthenticator) Authenticate(controlport *control.Conn) error {
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return errors.New("null authenticator provided, this control port is unsafe, start a new tor process instead")
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}
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