diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml index cb869ccf..629e4e37 100644 --- a/.github/workflows/ci.yml +++ b/.github/workflows/ci.yml @@ -164,6 +164,7 @@ jobs: ensure_same_swap_id, concurrent_bobs_before_xmr_lock_proof_sent, alice_manually_redeems_after_enc_sig_learned, + happy_path_bob_offline_while_alice_redeems_btc, ] runs-on: ubuntu-latest steps: diff --git a/swap/src/protocol/bob/state.rs b/swap/src/protocol/bob/state.rs index aa0045ea..58c1d723 100644 --- a/swap/src/protocol/bob/state.rs +++ b/swap/src/protocol/bob/state.rs @@ -489,6 +489,27 @@ pub struct State4 { } impl State4 { + pub async fn check_for_tx_redeem(&self, bitcoin_wallet: &bitcoin::Wallet) -> Result { + let tx_redeem = + bitcoin::TxRedeem::new(&self.tx_lock, &self.redeem_address, self.tx_redeem_fee); + let tx_redeem_encsig = self.b.encsign(self.S_a_bitcoin, tx_redeem.digest()); + + let tx_redeem_candidate = bitcoin_wallet.get_raw_transaction(tx_redeem.txid()).await?; + + let tx_redeem_sig = + tx_redeem.extract_signature_by_key(tx_redeem_candidate, self.b.public())?; + let s_a = bitcoin::recover(self.S_a_bitcoin, tx_redeem_sig, tx_redeem_encsig)?; + let s_a = monero::private_key_from_secp256k1_scalar(s_a.into()); + + Ok(State5 { + s_a, + s_b: self.s_b, + v: self.v, + tx_lock: self.tx_lock.clone(), + monero_wallet_restore_blockheight: self.monero_wallet_restore_blockheight, + }) + } + pub fn tx_redeem_encsig(&self) -> bitcoin::EncryptedSignature { let tx_redeem = bitcoin::TxRedeem::new(&self.tx_lock, &self.redeem_address, self.tx_redeem_fee); diff --git a/swap/src/protocol/bob/swap.rs b/swap/src/protocol/bob/swap.rs index 37a6b65a..8eaa1489 100644 --- a/swap/src/protocol/bob/swap.rs +++ b/swap/src/protocol/bob/swap.rs @@ -183,6 +183,13 @@ async fn next_state( } } BobState::XmrLocked(state) => { + // In case we send the encrypted signature to Alice, but she doesn't give us a confirmation + // We need to check if she still published the Bitcoin redeem transaction + // Otherwise we risk staying stuck in "XmrLocked" + if let Ok(state5) = state.check_for_tx_redeem(bitcoin_wallet).await { + return Ok(BobState::BtcRedeemed(state5)); + } + let tx_lock_status = bitcoin_wallet.subscribe_to(state.tx_lock.clone()).await; if let ExpiredTimelocks::None { .. } = state.expired_timelock(bitcoin_wallet).await? { @@ -207,6 +214,13 @@ async fn next_state( } } BobState::EncSigSent(state) => { + // We need to make sure that Alice did not publish the redeem transaction while we were offline + // Even if the cancel timelock expired, if Alice published the redeem transaction while we were away we cannot miss it + // If we do we cannot refund and will never be able to leave the "CancelTimelockExpired" state + if let Ok(state5) = state.check_for_tx_redeem(bitcoin_wallet).await { + return Ok(BobState::BtcRedeemed(state5)); + } + let tx_lock_status = bitcoin_wallet.subscribe_to(state.tx_lock.clone()).await; if let ExpiredTimelocks::None { .. } = state.expired_timelock(bitcoin_wallet).await? { diff --git a/swap/tests/happy_path_bob_offline_while_alice_redeems_btc.rs b/swap/tests/happy_path_bob_offline_while_alice_redeems_btc.rs new file mode 100644 index 00000000..c958c4f0 --- /dev/null +++ b/swap/tests/happy_path_bob_offline_while_alice_redeems_btc.rs @@ -0,0 +1,44 @@ +pub mod harness; + +use crate::harness::bob_run_until::is_encsig_sent; +use swap::asb::FixedRate; +use swap::protocol::bob::BobState; +use swap::protocol::{alice, bob}; +use tokio::join; + +#[tokio::test] +async fn given_bob_restarts_while_alice_redeems_btc() { + harness::setup_test(harness::SlowCancelConfig, |mut ctx| async move { + let (bob_swap, bob_handle) = ctx.bob_swap().await; + let swap_id = bob_swap.id; + + let bob_swap = tokio::spawn(bob::run_until(bob_swap, is_encsig_sent)); + + let alice_swap = ctx.alice_next_swap().await; + let alice_swap = tokio::spawn(alice::run(alice_swap, FixedRate::default())); + + let (bob_state, alice_state) = join!(bob_swap, alice_swap); + ctx.assert_alice_redeemed(alice_state??).await; + assert!(matches!(bob_state??, BobState::EncSigSent { .. })); + + let (bob_swap, _) = ctx.stop_and_resume_bob_from_db(bob_handle, swap_id).await; + + if let BobState::EncSigSent(state4) = bob_swap.state.clone() { + bob_swap + .bitcoin_wallet + .subscribe_to(state4.tx_lock) + .await + .wait_until_confirmed_with(state4.cancel_timelock) + .await?; + } else { + panic!("Bob in unexpected state {}", bob_swap.state); + } + + // Restart Bob + let bob_state = bob::run(bob_swap).await?; + ctx.assert_bob_redeemed(bob_state).await; + + Ok(()) + }) + .await; +} diff --git a/swap/tests/harness/mod.rs b/swap/tests/harness/mod.rs index c099376d..025b7e42 100644 --- a/swap/tests/harness/mod.rs +++ b/swap/tests/harness/mod.rs @@ -996,6 +996,10 @@ pub mod alice_run_until { pub fn is_encsig_learned(state: &AliceState) -> bool { matches!(state, AliceState::EncSigLearned { .. }) } + + pub fn is_btc_redeemed(state: &AliceState) -> bool { + matches!(state, AliceState::BtcRedeemed { .. }) + } } pub mod bob_run_until {