From e052c54d9b0e150a8df435528a6c03a624a76c47 Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Wed, 14 Feb 2024 15:47:22 +1030 Subject: [PATCH] lightningd: clean up close logic, fix bug where we can't override destination. Watchtowers changed the code so that we *always* have a channel->shutdown_scriptpubkey[LOCAL] (see new_channel()). The previous code had several problems: 1. It tested this for NULL, unnecessarily. 2. It allowed overriding if it was a default, *even* if we were already using it. 3. If the peer opened without option_shutdown_anysegwit, but upgraded before we closed, we would not recognize the default. 4. It set the final scriptpubkey (and other things!) even if the command failed. Changelog-Fixed: JSON-RPC: `close` with `destination` works even if prior `destination` was rejected. Signed-off-by: Rusty Russell --- lightningd/closing_control.c | 181 +++++++++++++++-------------------- tests/test_closing.py | 1 - 2 files changed, 79 insertions(+), 103 deletions(-) diff --git a/lightningd/closing_control.c b/lightningd/closing_control.c index 66477f56fc78..50181eda4a45 100644 --- a/lightningd/closing_control.c +++ b/lightningd/closing_control.c @@ -637,9 +637,9 @@ static struct command_result *json_close(struct command *cmd, struct channel *channel; unsigned int *timeout; const u8 *close_to_script = NULL; - u32 *final_index; - u32 index_val; - bool close_script_set, wrong_funding_changed, *force_lease_close; + u32 final_key_idx; + struct ext_key final_ext_key; + bool *force_lease_close; const char *fee_negotiation_step_str; struct bitcoin_outpoint *wrong_funding; u32 *feerate_range; @@ -686,79 +686,66 @@ static struct command_result *json_close(struct command *cmd, channel->lease_expiry, get_block_height(cmd->ld->topology)); - /* Set the wallet index to the default value; it is updated - * below if the close_to_script is found to be in the - * wallet. If the close_to_script is not in the wallet - * final_index will be set to NULL instead.*/ + /* Note: we don't change the channel until we're sure we succeed! */ assert(channel->final_key_idx <= UINT32_MAX); - index_val = (u32) channel->final_key_idx; - final_index = &index_val; + + if (close_to_script) { + bool is_p2sh; + + if (!tal_arr_eq(close_to_script, channel->shutdown_scriptpubkey[LOCAL])) { + const u8 *defp2tr, *defp2wpkh; + /* We cannot change the closing script once we've + * started shutdown: onchaind relies on it for output + * detection. However, we now set it at channel + * creation time, because we (ab)use it for the + * penalty output for watchtowers. So allow override + * here if we're not already closing, unless it's not + * the expected one, which would imply it was promised + * in open_channel/accept_channel so cannot be + * changed.*/ + if (channel_state_closing(channel->state)) { + return command_fail(cmd, JSONRPC2_INVALID_PARAMS, + "Destination address %s does not match " + "already-sent shutdown script %s", + tal_hex(tmpctx, channel->shutdown_scriptpubkey[LOCAL]), + tal_hex(tmpctx, close_to_script)); + } + + defp2tr = p2tr_for_keyidx(tmpctx, channel->peer->ld, channel->final_key_idx); + defp2wpkh = p2wpkh_for_keyidx(tmpctx, channel->peer->ld, channel->final_key_idx); + + if (!tal_arr_eq(channel->shutdown_scriptpubkey[LOCAL], defp2tr) + && !tal_arr_eq(channel->shutdown_scriptpubkey[LOCAL], defp2wpkh)) { + return command_fail(cmd, JSONRPC2_INVALID_PARAMS, + "Destination address %s does not match " + "previous shutdown script %s", + tal_hex(tmpctx, channel->shutdown_scriptpubkey[LOCAL]), + tal_hex(tmpctx, close_to_script)); + } + } + + /* If they give a local address, adjust final_key_idx. */ + if (!wallet_can_spend(cmd->ld->wallet, close_to_script, + &final_key_idx, &is_p2sh)) { + final_key_idx = channel->final_key_idx; + } + } else { + close_to_script = tal_dup_talarr(tmpctx, u8, channel->shutdown_scriptpubkey[LOCAL]); + final_key_idx = channel->final_key_idx; + } /* Don't send a scriptpubkey peer won't accept */ anysegwit = !chainparams->is_elements && feature_negotiated(cmd->ld->our_features, channel->peer->their_features, OPT_SHUTDOWN_ANYSEGWIT); - /* If we've set a local shutdown script for this peer, and it's not the - * default upfront script, try to close to a different channel. - * Error is an operator error */ - if (close_to_script - && channel->shutdown_scriptpubkey[LOCAL] - && !memeq(close_to_script, - tal_count(close_to_script), - channel->shutdown_scriptpubkey[LOCAL], - tal_count(channel->shutdown_scriptpubkey[LOCAL]))) { - u8 *default_close_to = NULL; - if (anysegwit) - default_close_to = p2tr_for_keyidx(tmpctx, cmd->ld, - channel->final_key_idx); - else - default_close_to = p2wpkh_for_keyidx(tmpctx, cmd->ld, - channel->final_key_idx); - if (!memeq(default_close_to, tal_count(default_close_to), - channel->shutdown_scriptpubkey[LOCAL], - tal_count(channel->shutdown_scriptpubkey[LOCAL]))) { - return command_fail(cmd, JSONRPC2_INVALID_PARAMS, - "Destination address %s does not match " - "previous shutdown script %s", - tal_hex(tmpctx, channel->shutdown_scriptpubkey[LOCAL]), - tal_hex(tmpctx, close_to_script)); - } else { - channel->shutdown_scriptpubkey[LOCAL] = - tal_free(channel->shutdown_scriptpubkey[LOCAL]); - channel->shutdown_scriptpubkey[LOCAL] = - tal_steal(channel, close_to_script); - close_script_set = true; - } - } else if (close_to_script && !channel->shutdown_scriptpubkey[LOCAL]) { - channel->shutdown_scriptpubkey[LOCAL] - = tal_steal(channel, cast_const(u8 *, close_to_script)); - close_script_set = true; - /* Is the close script in our wallet? */ - bool is_p2sh; - if (wallet_can_spend( - cmd->ld->wallet, - channel->shutdown_scriptpubkey[LOCAL], - &index_val, - &is_p2sh)) { - /* index_val has been set to the discovered wallet index */ - } else { - final_index = NULL; - } - } else if (!channel->shutdown_scriptpubkey[LOCAL]) { - channel->shutdown_scriptpubkey[LOCAL] - = p2wpkh_for_keyidx(channel, cmd->ld, channel->final_key_idx); - /* We don't save the default to disk */ - close_script_set = false; - } else - close_script_set = false; - - if (!valid_shutdown_scriptpubkey(channel->shutdown_scriptpubkey[LOCAL], - anysegwit, false)) { + /* In theory, this could happen if the peer had anysegwit when channel was + * established, and doesn't now. Doesn't happen, and if it did we could + * provide a new address manually. */ + if (!valid_shutdown_scriptpubkey(close_to_script, anysegwit, false)) { /* Explicit check for future segwits. */ if (!anysegwit && - valid_shutdown_scriptpubkey(channel->shutdown_scriptpubkey - [LOCAL], true, false)) { + valid_shutdown_scriptpubkey(close_to_script, true, false)) { return command_fail(cmd, JSONRPC2_INVALID_PARAMS, "Peer does not allow v1+ shutdown addresses"); } @@ -767,6 +754,16 @@ static struct command_result *json_close(struct command *cmd, "Invalid close destination"); } + if (bip32_key_from_parent(channel->peer->ld->bip32_base, + final_key_idx, + BIP32_FLAG_KEY_PUBLIC, + &final_ext_key) != WALLY_OK) { + return command_fail(cmd, LIGHTNINGD, + "Could not derive final_ext_key"); + } + + /* We change closing_fee_negotiation_step et al before we're sure, but it gets + * overridden every time anyway */ if (fee_negotiation_step_str == NULL) { channel->closing_fee_negotiation_step = 50; channel->closing_fee_negotiation_step_unit = @@ -818,17 +815,6 @@ static struct command_result *json_close(struct command *cmd, OPT_SHUTDOWN_WRONG_FUNDING) ? "yes" : "no"); } - - wrong_funding_changed = true; - channel->shutdown_wrong_funding - = tal_steal(channel, wrong_funding); - } else { - if (channel->shutdown_wrong_funding) { - channel->shutdown_wrong_funding - = tal_free(channel->shutdown_wrong_funding); - wrong_funding_changed = true; - } else - wrong_funding_changed = false; } /* May already be set by previous close cmd. */ @@ -862,29 +848,14 @@ static struct command_result *json_close(struct command *cmd, u8 *msg; if (streq(channel->owner->name, "dualopend")) { msg = towire_dualopend_send_shutdown( - NULL, - channel->shutdown_scriptpubkey[LOCAL]); + NULL, close_to_script); } else { - struct ext_key ext_key_val; - struct ext_key *final_ext_key = NULL; - if (final_index) { - if (bip32_key_from_parent( - channel->peer->ld->bip32_base, - *final_index, - BIP32_FLAG_KEY_PUBLIC, - &ext_key_val) != WALLY_OK) { - return command_fail( - cmd, LIGHTNINGD, - "Could not derive final_ext_key"); - } - final_ext_key = &ext_key_val; - } msg = towire_channeld_send_shutdown( NULL, - final_index, - final_ext_key, - channel->shutdown_scriptpubkey[LOCAL], - channel->shutdown_wrong_funding); + &final_key_idx, + &final_ext_key, + close_to_script, + wrong_funding); } subd_send_msg(channel->owner, take(msg)); } @@ -905,13 +876,19 @@ static struct command_result *json_close(struct command *cmd, channel_state_name(channel)); } + /* Now we have queued everything, we can commit channel changes. */ + tal_free(channel->shutdown_scriptpubkey[LOCAL]); + channel->shutdown_scriptpubkey[LOCAL] = tal_steal(channel, close_to_script); + channel->final_key_idx = final_key_idx; + + tal_free(channel->shutdown_wrong_funding); + channel->shutdown_wrong_funding = tal_steal(channel, wrong_funding); + /* Register this command for later handling. */ register_close_command(cmd->ld, cmd, channel, *timeout); - /* If we set `channel->shutdown_scriptpubkey[LOCAL]` or - * changed shutdown_wrong_funding, save it. */ - if (close_script_set || wrong_funding_changed) - wallet_channel_save(cmd->ld->wallet, channel); + /* In case we changed anything, save it. */ + wallet_channel_save(cmd->ld->wallet, channel); /* Wait until close drops down to chain. */ return command_still_pending(cmd); diff --git a/tests/test_closing.py b/tests/test_closing.py index e07deb1ac0e7..b949f19accdc 100644 --- a/tests/test_closing.py +++ b/tests/test_closing.py @@ -4034,7 +4034,6 @@ def test_closing_cpfp(node_factory, bitcoind): assert len(l2.rpc.listfunds()['outputs']) == 1 -@pytest.mark.xfail(strict=True) @unittest.skipIf(TEST_NETWORK == 'liquid-regtest', "Uses regtest addresses") def test_closing_no_anysegwit_retry(node_factory, bitcoind): """Sure, we reject the first time, but let them try again!"""