electrum

Electrum Bitcoin wallet
git clone https://git.parazyd.org/electrum
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commit 021f5d570ed8388f7d85f80172dfa7a6137600db
parent dfc2a35ae6220b8dbabb090ab1064a61cf19ce35
Author: SomberNight <somber.night@protonmail.com>
Date:   Tue, 26 Feb 2019 17:28:08 +0100

lnpeer: check that remote only sends commit_sig if there are changes

Diffstat:
Melectrum/lnpeer.py | 16+++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/electrum/lnpeer.py b/electrum/lnpeer.py @@ -36,7 +36,7 @@ from .lnutil import (Outpoint, LocalConfig, RECEIVED, UpdateAddHtlc, get_ln_flag_pair_of_bit, privkey_to_pubkey, UnknownPaymentHash, MIN_FINAL_CLTV_EXPIRY_ACCEPTED, LightningPeerConnectionClosed, HandshakeFailed, NotFoundChanAnnouncementForUpdate, MINIMUM_MAX_HTLC_VALUE_IN_FLIGHT_ACCEPTED, MAXIMUM_HTLC_MINIMUM_MSAT_ACCEPTED, - MAXIMUM_REMOTE_TO_SELF_DELAY_ACCEPTED) + MAXIMUM_REMOTE_TO_SELF_DELAY_ACCEPTED, RemoteMisbehaving) from .lntransport import LNTransport, LNTransportBase from .lnmsg import encode_msg, decode_msg @@ -79,6 +79,7 @@ class Peer(PrintError): self.attempted_route = {} self.orphan_channel_updates = OrderedDict() self.sent_commitment_for_ctn_last = defaultdict(lambda: None) # type: Dict[Channel, Optional[int]] + self.recv_commitment_for_ctn_last = defaultdict(lambda: None) # type: Dict[Channel, Optional[int]] self._local_changed_events = defaultdict(asyncio.Event) self._remote_changed_events = defaultdict(asyncio.Event) @@ -822,12 +823,13 @@ class Peer(PrintError): def maybe_send_commitment(self, chan: Channel): ctn_to_sign = chan.get_current_ctn(REMOTE) + 1 + # if there are no changes, we will not (and must not) send a new commitment pending, current = chan.hm.pending_htlcs(REMOTE), chan.hm.current_htlcs(REMOTE) - if (pending == current \ + if (pending == current and chan.pending_feerate(REMOTE) == chan.constraints.feerate) \ or ctn_to_sign == self.sent_commitment_for_ctn_last[chan]: return - self.print_error('send_commitment. old number htlcs: {len(current)}, new number htlcs: {len(pending)}') + self.print_error(f'send_commitment. old number htlcs: {len(current)}, new number htlcs: {len(pending)}') sig_64, htlc_sigs = chan.sign_next_commitment() self.send_message("commitment_signed", channel_id=chan.channel_id, signature=sig_64, num_htlcs=len(htlc_sigs), htlc_signature=b"".join(htlc_sigs)) self.sent_commitment_for_ctn_last[chan] = ctn_to_sign @@ -884,6 +886,14 @@ class Peer(PrintError): self.print_error("on_commitment_signed") channel_id = payload['channel_id'] chan = self.channels[channel_id] + ctn_to_recv = chan.get_current_ctn(LOCAL) + 1 + # make sure there were changes to the ctx, otherwise the remote peer is misbehaving + if (chan.hm.pending_htlcs(LOCAL) == chan.hm.current_htlcs(LOCAL) + and chan.pending_feerate(LOCAL) == chan.constraints.feerate) \ + or ctn_to_recv == self.recv_commitment_for_ctn_last[chan]: + raise RemoteMisbehaving('received commitment_signed without any change') + self.recv_commitment_for_ctn_last[chan] = ctn_to_recv + data = payload["htlc_signature"] htlc_sigs = [data[i:i+64] for i in range(0, len(data), 64)] chan.receive_new_commitment(payload["signature"], htlc_sigs)