13211764208

Committed 08 Feb 2025 03:08AM UTC coverage: 49.288% (-9.5%) from 58.815%

Build # 13211764208

Build Type

Pull #9489

github

Committed by

calvinrzachman

Commit Message

itest: verify switchrpc server enforces send then track

We prevent the rpc server from allowing onion dispatches for
attempt IDs which have already been tracked by rpc clients.

This helps protect the client from leaking a duplicate onion
attempt. NOTE: This is not the only method for solving this
issue! The issue could be addressed via careful client side
programming which accounts for the uncertainty and async
nature of dispatching onions to a remote process via RPC.
This would require some lnd ChannelRouter changes for how
we intend to use these RPCs though.

Pull Request Pull Request #9489: multi: add BuildOnion, SendOnion, and TrackOnion RPCs

Run Details

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65.47

/watchtower/blob/justice_kit_packet.go

package blob

import (
        "bytes"
        "crypto/rand"
        "encoding/binary"
        "errors"
        "fmt"
        "io"

        "github.com/btcsuite/btcd/btcec/v2"
        "github.com/btcsuite/btcd/btcec/v2/schnorr"
        "github.com/btcsuite/btcd/chaincfg/chainhash"
        "github.com/lightningnetwork/lnd/lnwire"
        "golang.org/x/crypto/chacha20poly1305"
)

const (
        // NonceSize is the length of a chacha20poly1305 nonce, 24 bytes.
        NonceSize = chacha20poly1305.NonceSizeX

        // KeySize is the length of a chacha20poly1305 key, 32 bytes.
        KeySize = chacha20poly1305.KeySize

        // CiphertextExpansion is the number of bytes padded to a plaintext
        // encrypted with chacha20poly1305, which comes from a 16-byte MAC.
        CiphertextExpansion = 16

        // V0PlaintextSize is the plaintext size of a version 0 encoded blob.
        //    sweep address length:            1 byte
        //    padded sweep address:           42 bytes
        //    revocation pubkey:              33 bytes
        //    local delay pubkey:             33 bytes
        //    csv delay:                       4 bytes
        //    commit to-local revocation sig: 64 bytes
        //    commit to-remote pubkey:        33 bytes, maybe blank
        //    commit to-remote sig:           64 bytes, maybe blank
        V0PlaintextSize = 274

        // V1PlaintextSize is the plaintext size of a version 1 encoded blob.
        //    sweep address length:            1 byte
        //    padded sweep address:           42 bytes
        //    revocation pubkey:              32 bytes
        //    local delay pubkey:             32 bytes
        //    commit to-local revocation sig: 64 bytes
        //    hash of to-local delay script:  32 bytes
        //    commit to-remote pubkey:        33 bytes, maybe blank
        //    commit to-remote sig:           64 bytes, maybe blank
        V1PlaintextSize = 300

        // MaxSweepAddrSize defines the maximum sweep address size that can be
        // encoded in a blob.
        MaxSweepAddrSize = 42
)

var (
        // byteOrder specifies a big-endian encoding of all integer values.
        byteOrder = binary.BigEndian

        // ErrUnknownBlobType signals that we don't understand the requested
        // blob encoding scheme.
        ErrUnknownBlobType = errors.New("unknown blob type")

        // ErrCiphertextTooSmall is a decryption error signaling that the
        // ciphertext is smaller than the ciphertext expansion factor.
        ErrCiphertextTooSmall = errors.New(
                "ciphertext is too small for chacha20poly1305",
        )

        // ErrNoCommitToRemoteOutput is returned when trying to retrieve the
        // commit to-remote output from the blob, though none exists.
        ErrNoCommitToRemoteOutput = errors.New(
                "cannot obtain commit to-remote p2wkh output script from blob",
        )

        // ErrSweepAddressToLong is returned when trying to encode or decode a
        // sweep address with length greater than the maximum length of 42
        // bytes, which supports p2wkh and p2sh addresses.
        ErrSweepAddressToLong = fmt.Errorf(
                "sweep address must be less than or equal to %d bytes long",
                MaxSweepAddrSize,
        )
)

// Size returns the size of the encoded-and-encrypted blob in bytes.
//
//        nonce:                24 bytes
//        enciphered plaintext:  n bytes
//        MAC:                  16 bytes
func Size(kit JusticeKit) int {
        return NonceSize + kit.PlainTextSize() + CiphertextExpansion
}

// schnorrPubKey is a 32-byte serialized x-only public key.
type schnorrPubKey [32]byte

// toBlobSchnorrPubKey serializes the given public key into a schnorrPubKey that
// can be set as a field on a JusticeKit.
func toBlobSchnorrPubKey(pubKey *btcec.PublicKey) schnorrPubKey {
        var blobPubKey schnorrPubKey
        copy(blobPubKey[:], schnorr.SerializePubKey(pubKey))
        return blobPubKey
}

// pubKey is a 33-byte, serialized compressed public key.
type pubKey [33]byte

// toBlobPubKey serializes the given public key into a pubKey that can be set
// as a field on a JusticeKit.
func toBlobPubKey(pk *btcec.PublicKey) pubKey {
        var blobPubKey pubKey
        copy(blobPubKey[:], pk.SerializeCompressed())
        return blobPubKey
}

// justiceKitPacketV0 is lé Blob of Justice. The JusticeKit contains information
// required to construct a justice transaction, that sweeps a remote party's
// revoked commitment transaction. It supports encryption and decryption using
// chacha20poly1305, allowing the client to encrypt the contents of the blob,
// and for a watchtower to later decrypt if action must be taken.
type justiceKitPacketV0 struct {
        // sweepAddress is the witness program of the output where the client's
        // fund will be deposited. This value is included in the blobs, as
        // opposed to the session info, such that the sweep addresses can't be
        // correlated across sessions and/or towers.
        //
        // NOTE: This is chosen to be the length of a maximally sized witness
        // program.
        sweepAddress []byte

        // revocationPubKey is the compressed pubkey that guards the revocation
        // clause of the remote party's to-local output.
        revocationPubKey pubKey

        // localDelayPubKey is the compressed pubkey in the to-local script of
        // the remote party, which guards the path where the remote party
        // claims their commitment output.
        localDelayPubKey pubKey

        // csvDelay is the relative timelock in the remote party's to-local
        // output, which the remote party must wait out before sweeping their
        // commitment output.
        csvDelay uint32

        // commitToLocalSig is a signature under RevocationPubKey using
        // SIGHASH_ALL.
        commitToLocalSig lnwire.Sig

        // commitToRemotePubKey is the public key in the to-remote output of the
        // revoked commitment transaction.
        //
        // NOTE: This value is only used if it contains a valid compressed
        // public key.
        commitToRemotePubKey pubKey

        // commitToRemoteSig is a signature under CommitToRemotePubKey using
        // SIGHASH_ALL.
        //
        // NOTE: This value is only used if CommitToRemotePubKey contains a
        // valid compressed public key.
        commitToRemoteSig lnwire.Sig
}

// Encrypt encodes the blob of justice using encoding version, and then
// creates a ciphertext using chacha20poly1305 under the chosen (nonce, key)
// pair.
//
// NOTE: It is the caller's responsibility to ensure that this method is only
// called once for a given (nonce, key) pair.
func Encrypt(kit JusticeKit, key BreachKey) ([]byte, error) {
        // Encode the plaintext using the provided version, to obtain the
        // plaintext bytes.
        var ptxtBuf bytes.Buffer
        err := kit.encode(&ptxtBuf)
        if err != nil {
                return nil, err
        }

        // Create a new chacha20poly1305 cipher, using a 32-byte key.
        cipher, err := chacha20poly1305.NewX(key[:])
        if err != nil {
                return nil, err
        }

        // Allocate the ciphertext, which will contain the nonce, encrypted
        // plaintext and MAC.
        plaintext := ptxtBuf.Bytes()
        ciphertext := make([]byte, Size(kit))

        // Generate a random  24-byte nonce in the ciphertext's prefix.
        nonce := ciphertext[:NonceSize]
        if _, err := io.ReadFull(rand.Reader, nonce); err != nil {
                return nil, err
        }

        // Finally, encrypt the plaintext using the given nonce, storing the
        // result in the ciphertext buffer.
        cipher.Seal(ciphertext[NonceSize:NonceSize], nonce, plaintext, nil)

        return ciphertext, nil
}

// Decrypt unenciphers a blob of justice by decrypting the ciphertext using
// chacha20poly1305 with the chosen (nonce, key) pair. The internal plaintext is
// then deserialized using the given encoding version.
func Decrypt(key BreachKey, ciphertext []byte,
        blobType Type) (JusticeKit, error) {

        // Fail if the blob's overall length is less than required for the nonce
        // and expansion factor.
        if len(ciphertext) < NonceSize+CiphertextExpansion {
                return nil, ErrCiphertextTooSmall
        }

        // Create a new chacha20poly1305 cipher, using a 32-byte key.
        cipher, err := chacha20poly1305.NewX(key[:])
        if err != nil {
                return nil, err
        }

        // Allocate the final buffer that will contain the blob's plaintext
        // bytes, which is computed by subtracting the ciphertext expansion
        // factor from the blob's length.
        plaintext := make([]byte, len(ciphertext)-CiphertextExpansion)

        // Decrypt the ciphertext, placing the resulting plaintext in our
        // plaintext buffer.
        nonce := ciphertext[:NonceSize]
        _, err = cipher.Open(plaintext[:0], nonce, ciphertext[NonceSize:], nil)
        if err != nil {
                return nil, err
        }

        commitment, err := blobType.CommitmentType(nil)
        if err != nil {
                return nil, err
        }

        kit, err := commitment.EmptyJusticeKit()
        if err != nil {
                return nil, err
        }

        // If decryption succeeded, we will then decode the plaintext bytes
        // using the specified blob version.
        err = kit.decode(bytes.NewReader(plaintext))
        if err != nil {
                return nil, err
        }

        return kit, nil
}

// encode encodes the JusticeKit using the version 0 encoding scheme to the
// provided io.Writer. The encoding supports sweeping of the commit to-local
// output, and  optionally the  commit to-remote output. The encoding produces a
// constant-size plaintext size of 274 bytes.
//
// blob version 0 plaintext encoding:
//
//        sweep address length:            1 byte
//        padded sweep address:           42 bytes
//        revocation pubkey:              33 bytes
//        local delay pubkey:             33 bytes
//        csv delay:                       4 bytes
//        commit to-local revocation sig: 64 bytes
//        commit to-remote pubkey:        33 bytes, maybe blank
//        commit to-remote sig:           64 bytes, maybe blank
func (b *justiceKitPacketV0) encode(w io.Writer) error {
        // Assert the sweep address length is sane.
        if len(b.sweepAddress) > MaxSweepAddrSize {
                return ErrSweepAddressToLong
        }

        // Write the actual length of the sweep address as a single byte.
        err := binary.Write(w, byteOrder, uint8(len(b.sweepAddress)))
        if err != nil {
                return err
        }

        // Pad the sweep address to our maximum length of 42 bytes.
        var sweepAddressBuf [MaxSweepAddrSize]byte
        copy(sweepAddressBuf[:], b.sweepAddress)

        // Write padded 42-byte sweep address.
        _, err = w.Write(sweepAddressBuf[:])
        if err != nil {
                return err
        }

        // Write 33-byte revocation public key.
        _, err = w.Write(b.revocationPubKey[:])
        if err != nil {
                return err
        }

        // Write 33-byte local delay public key.
        _, err = w.Write(b.localDelayPubKey[:])
        if err != nil {
                return err
        }

        // Write 4-byte CSV delay.
        err = binary.Write(w, byteOrder, b.csvDelay)
        if err != nil {
                return err
        }

        // Write 64-byte revocation signature for commit to-local output.
        _, err = w.Write(b.commitToLocalSig.RawBytes())
        if err != nil {
                return err
        }

        // Write 33-byte commit to-remote public key, which may be blank.
        _, err = w.Write(b.commitToRemotePubKey[:])
        if err != nil {
                return err
        }

        // Write 64-byte commit to-remote signature, which may be blank.
        _, err = w.Write(b.commitToRemoteSig.RawBytes())

        return err
}

// decode reconstructs a JusticeKit from the io.Reader, using version 0
// encoding scheme. This will parse a constant size input stream of 274 bytes to
// recover information for the commit to-local output, and possibly the commit
// to-remote output.
//
// blob version 0 plaintext encoding:
//
//        sweep address length:            1 byte
//        padded sweep address:           42 bytes
//        revocation pubkey:              33 bytes
//        local delay pubkey:             33 bytes
//        csv delay:                       4 bytes
//        commit to-local revocation sig: 64 bytes
//        commit to-remote pubkey:        33 bytes, maybe blank
//        commit to-remote sig:           64 bytes, maybe blank
func (b *justiceKitPacketV0) decode(r io.Reader) error {
        // Read the sweep address length as a single byte.
        var sweepAddrLen uint8
        err := binary.Read(r, byteOrder, &sweepAddrLen)
        if err != nil {
                return err
        }

        // Assert the sweep address length is sane.
        if sweepAddrLen > MaxSweepAddrSize {
                return ErrSweepAddressToLong
        }

        // Read padded 42-byte sweep address.
        var sweepAddressBuf [MaxSweepAddrSize]byte
        _, err = io.ReadFull(r, sweepAddressBuf[:])
        if err != nil {
                return err
        }

        // Parse sweep address from padded buffer.
        b.sweepAddress = make([]byte, sweepAddrLen)
        copy(b.sweepAddress, sweepAddressBuf[:])

        // Read 33-byte revocation public key.
        _, err = io.ReadFull(r, b.revocationPubKey[:])
        if err != nil {
                return err
        }

        // Read 33-byte local delay public key.
        _, err = io.ReadFull(r, b.localDelayPubKey[:])
        if err != nil {
                return err
        }

        // Read 4-byte CSV delay.
        err = binary.Read(r, byteOrder, &b.csvDelay)
        if err != nil {
                return err
        }

        // Read 64-byte revocation signature for commit to-local output.
        var localSig [64]byte
        _, err = io.ReadFull(r, localSig[:])
        if err != nil {
                return err
        }

        b.commitToLocalSig, err = lnwire.NewSigFromWireECDSA(localSig[:])
        if err != nil {
                return err
        }

        var (
                commitToRemotePubkey pubKey
                commitToRemoteSig    [64]byte
        )

        // Read 33-byte commit to-remote public key, which may be discarded.
        _, err = io.ReadFull(r, commitToRemotePubkey[:])
        if err != nil {
                return err
        }

        // Read 64-byte commit to-remote signature, which may be discarded.
        _, err = io.ReadFull(r, commitToRemoteSig[:])
        if err != nil {
                return err
        }

        // Only populate the commit to-remote fields in the decoded blob if a
        // valid compressed public key was read from the reader.
        if btcec.IsCompressedPubKey(commitToRemotePubkey[:]) {
                b.commitToRemotePubKey = commitToRemotePubkey
                b.commitToRemoteSig, err = lnwire.NewSigFromWireECDSA(
                        commitToRemoteSig[:],
                )
                if err != nil {
                        return err
                }
        }

        return nil
}

// justiceKitPacketV1 is the Blob of Justice for taproot channels.
type justiceKitPacketV1 struct {
        // sweepAddress is the witness program of the output where the client's
        // fund will be deposited. This value is included in the blobs, as
        // opposed to the session info, such that the sweep addresses can't be
        // correlated across sessions and/or towers.
        //
        // NOTE: This is chosen to be the length of a maximally sized witness
        // program.
        sweepAddress []byte

        // revocationPubKey is the x-only pubkey that guards the revocation
        // clause of the remote party's to-local output.
        revocationPubKey schnorrPubKey

        // localDelayPubKey is the x-only pubkey in the to-local script of
        // the remote party, which guards the path where the remote party
        // claims their commitment output.
        localDelayPubKey schnorrPubKey

        // delayScriptHash is the hash of the to_local delay script that is used
        // in the TapTree.
        delayScriptHash [chainhash.HashSize]byte

        // commitToLocalSig is a signature under revocationPubKey using
        // SIGHASH_DEFAULT.
        commitToLocalSig lnwire.Sig

        // commitToRemotePubKey is the public key in the to-remote output of the
        // revoked commitment transaction. This uses a 33-byte compressed pubkey
        // encoding unlike the other public keys because it will not always be
        // present and so this gives us an easy way to check if it is present or
        // not.
        //
        // NOTE: This value is only used if it contains a valid compressed
        // public key.
        commitToRemotePubKey pubKey

        // commitToRemoteSig is a signature under commitToRemotePubKey using
        // SIGHASH_DEFAULT.
        //
        // NOTE: This value is only used if commitToRemotePubKey contains a
        // valid compressed public key.
        commitToRemoteSig lnwire.Sig
}

// encode encodes the justiceKitPacketV1 to the provided io.Writer. The encoding
// supports sweeping of the commit to-local output, and optionally the commit
// to-remote output. The encoding produces a constant-size plaintext size of
// 300 bytes.
//
// blob version 1 plaintext encoding:
//
//        sweep address length:            1 byte
//        padded sweep address:           42 bytes
//        revocation pubkey:              32 bytes
//        local delay pubkey:             32 bytes
//        commit to-local revocation sig: 64 bytes
//        hash of to-local delay script:  32 bytes
//        commit to-remote pubkey:        33 bytes, maybe blank
//        commit to-remote sig:           64 bytes, maybe blank
func (t *justiceKitPacketV1) encode(w io.Writer) error {
        // Assert the sweep address length is sane.
        if len(t.sweepAddress) > MaxSweepAddrSize {
                return ErrSweepAddressToLong
        }

        // Write the actual length of the sweep address as a single byte.
        err := binary.Write(w, byteOrder, uint8(len(t.sweepAddress)))
        if err != nil {
                return err
        }

        // Pad the sweep address to our maximum length of 42 bytes.
        var sweepAddressBuf [MaxSweepAddrSize]byte
        copy(sweepAddressBuf[:], t.sweepAddress)

        // Write padded 42-byte sweep address.
        _, err = w.Write(sweepAddressBuf[:])
        if err != nil {
                return err
        }

        // Write 32-byte revocation public key.
        _, err = w.Write(t.revocationPubKey[:])
        if err != nil {
                return err
        }

        // Write 32-byte local delay public key.
        _, err = w.Write(t.localDelayPubKey[:])
        if err != nil {
                return err
        }

        // Write 64-byte revocation signature for commit to-local output.
        _, err = w.Write(t.commitToLocalSig.RawBytes())
        if err != nil {
                return err
        }

        // Write 32-byte hash of the to-local delay script.
        _, err = w.Write(t.delayScriptHash[:])
        if err != nil {
                return err
        }

        // Write 33-byte commit to-remote public key, which may be blank.
        _, err = w.Write(t.commitToRemotePubKey[:])
        if err != nil {
                return err
        }

        // Write 64-byte commit to-remote signature, which may be blank.
        _, err = w.Write(t.commitToRemoteSig.RawBytes())

        return err
}

// decode reconstructs a justiceKitPacketV1 from the io.Reader, using version 1
// encoding scheme. This will parse a constant size input stream of 300 bytes to
// recover information for the commit to-local output, and possibly the commit
// to-remote output.
//
// blob version 1 plaintext encoding:
//
//        sweep address length:            1 byte
//        padded sweep address:           42 bytes
//        revocation pubkey:              32 bytes
//        local delay pubkey:             32 bytes
//        commit to-local revocation sig: 64 bytes
//        hash of to-local delay script:  32 bytes
//        commit to-remote pubkey:        33 bytes, maybe blank
//        commit to-remote sig:           64 bytes, maybe blank
func (t *justiceKitPacketV1) decode(r io.Reader) error {
        // Read the sweep address length as a single byte.
        var sweepAddrLen uint8
        err := binary.Read(r, byteOrder, &sweepAddrLen)
        if err != nil {
                return err
        }
        // Assert the sweep address length is sane.
        if sweepAddrLen > MaxSweepAddrSize {
                return ErrSweepAddressToLong
        }
        // Read padded 42-byte sweep address.
        var sweepAddressBuf [MaxSweepAddrSize]byte
        _, err = io.ReadFull(r, sweepAddressBuf[:])
        if err != nil {
                return err
        }

        // Parse sweep address from padded buffer.
        t.sweepAddress = make([]byte, sweepAddrLen)
        copy(t.sweepAddress, sweepAddressBuf[:])

        // Read 32-byte revocation public key.
        _, err = io.ReadFull(r, t.revocationPubKey[:])
        if err != nil {
                return err
        }

        // Read 32-byte local delay public key.
        _, err = io.ReadFull(r, t.localDelayPubKey[:])
        if err != nil {
                return err
        }

        // Read 64-byte revocation signature for commit to-local output.
        var localSig [64]byte
        _, err = io.ReadFull(r, localSig[:])
        if err != nil {
                return err
        }

        // Read 32-byte to-local delay script hash.
        _, err = io.ReadFull(r, t.delayScriptHash[:])
        if err != nil {
                return err
        }

        t.commitToLocalSig, err = lnwire.NewSigFromSchnorrRawSignature(
                localSig[:],
        )
        if err != nil {
                return err
        }
        var (
                commitToRemotePubkey pubKey
                commitToRemoteSig    [64]byte
        )
        // Read 33-byte commit to-remote public key, which may be discarded.
        _, err = io.ReadFull(r, commitToRemotePubkey[:])
        if err != nil {
                return err
        }
        // Read 64-byte commit to-remote signature, which may be discarded.
        _, err = io.ReadFull(r, commitToRemoteSig[:])
        if err != nil {
                return err
        }

        // Only populate the commit to-remote fields in the decoded blob if a
        // valid compressed public key was read from the reader.
        if !btcec.IsCompressedPubKey(commitToRemotePubkey[:]) {
                return nil
        }

        t.commitToRemotePubKey = commitToRemotePubkey
        t.commitToRemoteSig, err = lnwire.NewSigFromSchnorrRawSignature(
                commitToRemoteSig[:],
        )
        if err != nil {
                return err
        }

        return nil
}

lightningnetwork / lnd / 13211764208

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