AaronFiore/electrum
1
0
Fork 0
Code Activity

lnchannel: handle htlc-address collisions

Browse Source 
We were previously generating an incorrect commitment_signed msg if there were
multiple htlcs sharing the same scriptPubKey.
This commit is contained in:
SomberNight
2019-09-07 07:37:13 +02:00
parent 00f15d491b
commit 83fcdbd561
4 changed files with 219 additions and 157 deletions
Download Patch File Download Diff File Expand all files Collapse all files

76
electrum/lnutil.py
View File

@@ -5,7 +5,7 @@
from enum import IntFlag, IntEnum
import json
from collections import namedtuple
from typing import NamedTuple, List, Tuple, Mapping, Optional, TYPE_CHECKING, Union, Dict
from typing import NamedTuple, List, Tuple, Mapping, Optional, TYPE_CHECKING, Union, Dict, Set
import re
from .util import bfh, bh2u, inv_dict
@@ -50,7 +50,7 @@ class LocalConfig(NamedTuple):
funding_locked_received: bool
was_announced: bool
current_commitment_signature: Optional[bytes]
current_htlc_signatures: List[bytes]
current_htlc_signatures: bytes
class RemoteConfig(NamedTuple):
@@ -383,10 +383,63 @@ def get_ordered_channel_configs(chan: 'Channel', for_us: bool) -> Tuple[Union[Lo
return conf, other_conf
def make_htlc_tx_with_open_channel(chan: 'Channel', pcp: bytes, for_us: bool,
we_receive: bool, commit: Transaction,
htlc: 'UpdateAddHtlc', name: str = None, cltv_expiry: int = 0) -> Tuple[bytes, Transaction]:
def possible_output_idxs_of_htlc_in_ctx(*, chan: 'Channel', pcp: bytes, subject: 'HTLCOwner',
htlc_direction: 'Direction', ctx: Transaction,
htlc: 'UpdateAddHtlc') -> Set[int]:
amount_msat, cltv_expiry, payment_hash = htlc.amount_msat, htlc.cltv_expiry, htlc.payment_hash
for_us = subject == LOCAL
conf, other_conf = get_ordered_channel_configs(chan=chan, for_us=for_us)
other_revocation_pubkey = derive_blinded_pubkey(other_conf.revocation_basepoint.pubkey, pcp)
other_htlc_pubkey = derive_pubkey(other_conf.htlc_basepoint.pubkey, pcp)
htlc_pubkey = derive_pubkey(conf.htlc_basepoint.pubkey, pcp)
preimage_script = make_htlc_output_witness_script(is_received_htlc=htlc_direction == RECEIVED,
remote_revocation_pubkey=other_revocation_pubkey,
remote_htlc_pubkey=other_htlc_pubkey,
local_htlc_pubkey=htlc_pubkey,
payment_hash=payment_hash,
cltv_expiry=cltv_expiry)
htlc_address = redeem_script_to_address('p2wsh', bh2u(preimage_script))
candidates = ctx.get_output_idxs_from_address(htlc_address)
return {output_idx for output_idx in candidates
if ctx.outputs()[output_idx].value == htlc.amount_msat // 1000}
def map_htlcs_to_ctx_output_idxs(*, chan: 'Channel', ctx: Transaction, pcp: bytes,
subject: 'HTLCOwner', ctn: int) -> Dict[Tuple['Direction', 'UpdateAddHtlc'], Tuple[int, int]]:
"""Returns a dict from (htlc_dir, htlc) to (ctx_output_idx, htlc_relative_idx)"""
htlc_to_ctx_output_idx_map = {} # type: Dict[Tuple[Direction, UpdateAddHtlc], int]
unclaimed_ctx_output_idxs = set(range(len(ctx.outputs())))
offered_htlcs = chan.included_htlcs(subject, SENT, ctn=ctn)
offered_htlcs.sort(key=lambda htlc: htlc.cltv_expiry)
received_htlcs = chan.included_htlcs(subject, RECEIVED, ctn=ctn)
received_htlcs.sort(key=lambda htlc: htlc.cltv_expiry)
for direction, htlcs in zip([SENT, RECEIVED], [offered_htlcs, received_htlcs]):
for htlc in htlcs:
cands = sorted(possible_output_idxs_of_htlc_in_ctx(chan=chan,
pcp=pcp,
subject=subject,
htlc_direction=direction,
ctx=ctx,
htlc=htlc))
for ctx_output_idx in cands:
if ctx_output_idx in unclaimed_ctx_output_idxs:
unclaimed_ctx_output_idxs.discard(ctx_output_idx)
htlc_to_ctx_output_idx_map[(direction, htlc)] = ctx_output_idx
break
# calc htlc_relative_idx
inverse_map = {ctx_output_idx: (direction, htlc)
for ((direction, htlc), ctx_output_idx) in htlc_to_ctx_output_idx_map.items()}
return {inverse_map[ctx_output_idx]: (ctx_output_idx, htlc_relative_idx)
for htlc_relative_idx, ctx_output_idx in enumerate(sorted(inverse_map))}
def make_htlc_tx_with_open_channel(*, chan: 'Channel', pcp: bytes, subject: 'HTLCOwner',
htlc_direction: 'Direction', commit: Transaction, ctx_output_idx: int,
htlc: 'UpdateAddHtlc', name: str = None) -> Tuple[bytes, Transaction]:
amount_msat, cltv_expiry, payment_hash = htlc.amount_msat, htlc.cltv_expiry, htlc.payment_hash
for_us = subject == LOCAL
conf, other_conf = get_ordered_channel_configs(chan=chan, for_us=for_us)
delayedpubkey = derive_pubkey(conf.delayed_basepoint.pubkey, pcp)
@@ -395,8 +448,8 @@ def make_htlc_tx_with_open_channel(chan: 'Channel', pcp: bytes, for_us: bool,
htlc_pubkey = derive_pubkey(conf.htlc_basepoint.pubkey, pcp)
# HTLC-success for the HTLC spending from a received HTLC output
# if we do not receive, and the commitment tx is not for us, they receive, so it is also an HTLC-success
is_htlc_success = for_us == we_receive
script, htlc_tx_output = make_htlc_tx_output(
is_htlc_success = htlc_direction == RECEIVED
witness_script_of_htlc_tx_output, htlc_tx_output = make_htlc_tx_output(
amount_msat = amount_msat,
local_feerate = chan.get_next_feerate(LOCAL if for_us else REMOTE),
revocationpubkey=other_revocation_pubkey,
@@ -409,20 +462,15 @@ def make_htlc_tx_with_open_channel(chan: 'Channel', pcp: bytes, for_us: bool,
local_htlc_pubkey=htlc_pubkey,
payment_hash=payment_hash,
cltv_expiry=cltv_expiry)
htlc_address = redeem_script_to_address('p2wsh', bh2u(preimage_script))
# FIXME handle htlc_address collision
# also: https://github.com/lightningnetwork/lightning-rfc/issues/448
prevout_idx = commit.get_output_idx_from_address(htlc_address)
assert prevout_idx is not None, (htlc_address, commit.outputs(), extract_ctn_from_tx_and_chan(commit, chan))
htlc_tx_inputs = make_htlc_tx_inputs(
commit.txid(), prevout_idx,
commit.txid(), ctx_output_idx,
amount_msat=amount_msat,
witness_script=bh2u(preimage_script))
if is_htlc_success:
cltv_expiry = 0
htlc_tx = make_htlc_tx(cltv_expiry, inputs=htlc_tx_inputs, output=htlc_tx_output,
name=name, cltv_expiry=cltv_expiry)
return script, htlc_tx
return witness_script_of_htlc_tx_output, htlc_tx
def make_funding_input(local_funding_pubkey: bytes, remote_funding_pubkey: bytes,
funding_pos: int, funding_txid: bytes, funding_sat: int):