From 9014cb9a13e795a7ab83331bd806ec6af07c5b87 Mon Sep 17 00:00:00 2001
From: rishflab <rishflab@hotmail.com>
Date: Mon, 21 Dec 2020 11:17:54 +1100
Subject: [PATCH] Fix tx_cancel building and signing

In an earlier commit we moved the signing and building of tx_cancel into a reusable
function. This was a mistake as the signing logic is different for Alice and Bob.
---
 xmr-btc/src/alice.rs   | 22 +++++++++++++---------
 xmr-btc/src/bitcoin.rs | 34 ----------------------------------
 xmr-btc/src/bob.rs     | 27 ++++++++++++++++++---------
 3 files changed, 31 insertions(+), 52 deletions(-)

diff --git a/xmr-btc/src/alice.rs b/xmr-btc/src/alice.rs
index 3ac3cc24..3bf77cfb 100644
--- a/xmr-btc/src/alice.rs
+++ b/xmr-btc/src/alice.rs
@@ -720,15 +720,19 @@ impl State3 {
     where
         W: BroadcastSignedTransaction,
     {
-        crate::bitcoin::publish_cancel_transaction(
-            self.tx_lock.clone(),
-            self.a.clone(),
-            self.B,
-            self.refund_timelock,
-            self.tx_punish_sig_bob.clone(),
-            bitcoin_wallet,
-        )
-        .await
+        let tx_cancel = self.tx_cancel();
+
+        let sig_a = self.a.sign(tx_cancel.digest());
+        let sig_b = self.tx_cancel_sig_bob.clone();
+
+        let signed_tx_cancel = tx_cancel
+            .clone()
+            .add_signatures(&self.tx_lock, (self.a.public(), sig_a), (self.B, sig_b))
+            .expect("sig_{a,b} to be valid signatures for tx_cancel");
+
+        bitcoin_wallet
+            .broadcast_signed_transaction(signed_tx_cancel)
+            .await
     }
 }
 
diff --git a/xmr-btc/src/bitcoin.rs b/xmr-btc/src/bitcoin.rs
index 1c959c6a..562b262f 100644
--- a/xmr-btc/src/bitcoin.rs
+++ b/xmr-btc/src/bitcoin.rs
@@ -243,37 +243,3 @@ where
         tokio::time::delay_for(std::time::Duration::from_secs(1)).await;
     }
 }
-
-pub async fn publish_cancel_transaction<W>(
-    tx_lock: TxLock,
-    secret_key: crate::bitcoin::SecretKey,
-    public_key: crate::bitcoin::PublicKey,
-    refund_timelock: u32,
-    tx_cancel_sig: crate::bitcoin::Signature,
-    bitcoin_wallet: &W,
-) -> Result<Txid>
-where
-    W: BroadcastSignedTransaction,
-{
-    let tx_cancel =
-        crate::bitcoin::TxCancel::new(&tx_lock, refund_timelock, public_key, secret_key.public());
-
-    let sig_theirs = tx_cancel_sig.clone();
-    let sig_ours = secret_key.sign(tx_cancel.digest());
-
-    let tx_cancel_txn = tx_cancel
-        .clone()
-        .add_signatures(
-            &tx_lock,
-            (public_key, sig_theirs),
-            (secret_key.public(), sig_ours),
-        )
-        .expect(
-            "sig_{a,b} to be valid signatures for
-                tx_cancel",
-        );
-
-    bitcoin_wallet
-        .broadcast_signed_transaction(tx_cancel_txn)
-        .await
-}
diff --git a/xmr-btc/src/bob.rs b/xmr-btc/src/bob.rs
index f57576fc..317e9f6c 100644
--- a/xmr-btc/src/bob.rs
+++ b/xmr-btc/src/bob.rs
@@ -660,19 +660,28 @@ impl State4 {
         self.b.encsign(self.S_a_bitcoin, tx_redeem.digest())
     }
 
+    pub fn tx_cancel(&self) -> TxCancel {
+        crate::bitcoin::TxCancel::new(&self.tx_lock, self.refund_timelock, self.A, self.b.public())
+    }
+
     pub async fn submit_tx_cancel<W>(&self, bitcoin_wallet: &W) -> Result<Txid>
     where
         W: BroadcastSignedTransaction,
     {
-        crate::bitcoin::publish_cancel_transaction(
-            self.tx_lock.clone(),
-            self.b.clone(),
-            self.A,
-            self.refund_timelock,
-            self.tx_cancel_sig_a.clone(),
-            bitcoin_wallet,
-        )
-        .await
+        let tx_cancel = self.tx_cancel();
+
+        let sig_b = self.b.sign(tx_cancel.digest());
+        let sig_a = self.tx_cancel_sig_a.clone();
+
+        let signed_tx_cancel = tx_cancel.clone().add_signatures(
+            &self.tx_lock,
+            (self.A, sig_a),
+            (self.b.public(), sig_b),
+        )?;
+
+        bitcoin_wallet
+            .broadcast_signed_transaction(signed_tx_cancel)
+            .await
     }
 
     pub async fn watch_for_redeem_btc<W>(&self, bitcoin_wallet: &W) -> Result<State5>