client/eth: Warn instead of fail on audit coinID/txHash mismatch.

Some RPC providers return unsigned transaction data, causing the
deserialized tx hash to differ from the on-chain tx hash (coinID).
The contract state is validated against the locator from the contract
data, not the tx hash, so the mismatch is not a security concern.

Author: vboxuser

client/asset/eth/eth.go

@@ -5865,20 +5865,25 @@ func (eth *baseWallet) SignCoinMessage(_ asset.Coin, msg dex.Bytes) (pubkeys, si
 
 // AuditContract retrieves information about a swap contract on the
 // blockchain. This would be used to verify the counter-party's contract
-// during a swap. coinID is expected to be the transaction id, and must
-// be the same as the hash of serializedTx. contract is expected to be
-// (contractVersion|secretHash) where the secretHash uniquely keys the swap.
+// during a swap. coinID is expected to be the transaction id. contract
+// is expected to be (contractVersion|secretHash) where the secretHash
+// uniquely keys the swap.
 func (w *assetWallet) AuditContract(coinID, contract, serializedTx dex.Bytes, rebroadcast bool) (*asset.AuditInfo, error) {
-	w.log.Debugf("AuditContract: coinID len=%d hex=%x", len(coinID), []byte(coinID))
 	tx := new(types.Transaction)
 	err := tx.UnmarshalBinary(serializedTx)
 	if err != nil {
 		return nil, fmt.Errorf("AuditContract: failed to unmarshal transaction: %w", err)
 	}
 
+	// The deserialized tx hash may not match coinID if the RPC provider
+	// returned the transaction without signature data. This is acceptable
+	// because the contract state is validated against the locator from the
+	// contract data, not the tx hash. Use the coinID as the canonical hash.
 	txHash := tx.Hash()
 	if !bytes.Equal(coinID, txHash[:]) {
-		return nil, fmt.Errorf("AuditContract: coin id != txHash - coin id: %x, txHash: %s", coinID, tx.Hash())
+		w.log.Warnf("AuditContract: coinID %x differs from deserialized txHash %s (unsigned tx from RPC?). Proceeding with contract validation.",
+			[]byte(coinID), txHash)
+		copy(txHash[:], coinID)
 	}
 
 	version, locator, err := dexeth.DecodeContractData(contract)

client/asset/eth/eth_test.go

@@ -4725,8 +4725,9 @@ func testAuditContract(t *testing.T, assetID uint32) {
 					Value:       dexeth.GweiToWei(1),
 				},
 			},
-			differentHash: true,
-			wantErr:       true,
+			differentHash:  true,
+			wantRecipient:  testAddressA.Hex(),
+			wantExpiration: now,
 		},
 		{
 			name:     "contract is invalid versioned bytes",

client/core/core.go

@@ -10288,12 +10288,10 @@ func (c *Core) schedTradeTick(tracker *trackedTrade) {
 // when a match counter-party reports their initiation transaction.
 func handleAuditRoute(c *Core, dc *dexConnection, msg *msgjson.Message) error {
 	audit := new(msgjson.Audit)
-	c.log.Debugf("handleAuditRoute: raw payload: %s", string(msg.Payload))
 	err := msg.Unmarshal(audit)
 	if err != nil {
 		return fmt.Errorf("audit request parsing error: %w", err)
 	}
-	c.log.Debugf("handleAuditRoute: CoinID len=%d hex=%x", len(audit.CoinID), audit.CoinID)
 	var oid order.OrderID
 	copy(oid[:], audit.OrderID)
 

client/core/trade.go

@@ -3932,7 +3932,6 @@ func (t *trackedTrade) searchAuditInfo(match *matchTracker, coinID []byte, contr
 		Expiration: time.Now().Add(24 * time.Hour), // effectively forever
 		TryFunc: func() wait.TryDirective {
 			var err error
-			t.dc.log.Debugf("searchAuditInfo: calling AuditContract with coinID len=%d hex=%x", len(coinID), []byte(coinID))
 			auditInfo, err = toWallet.AuditContract(coinID, contract, txData, true)
 			if err == nil {
 				// Success.