rpc: Fixed signed integer overflow for large feerates

Author: MarcoFalke

src/rpc/mempool.cpp

@@ -81,9 +81,7 @@ static RPCHelpMan sendrawtransaction()
 
             CTransactionRef tx(MakeTransactionRef(std::move(mtx)));
 
-            const CFeeRate max_raw_tx_fee_rate = request.params[1].isNull() ?
-                                                     DEFAULT_MAX_RAW_TX_FEE_RATE :
-                                                     CFeeRate(AmountFromValue(request.params[1]));
+            const CFeeRate max_raw_tx_fee_rate{ParseFeeRate(self.Arg<UniValue>(1))};
 
             int64_t virtual_size = GetVirtualTransactionSize(*tx);
             CAmount max_raw_tx_fee = max_raw_tx_fee_rate.GetFee(virtual_size);
@@ -162,9 +160,7 @@ static RPCHelpMan testmempoolaccept()
                                    "Array must contain between 1 and " + ToString(MAX_PACKAGE_COUNT) + " transactions.");
             }
 
-            const CFeeRate max_raw_tx_fee_rate = request.params[1].isNull() ?
-                                                     DEFAULT_MAX_RAW_TX_FEE_RATE :
-                                                     CFeeRate(AmountFromValue(request.params[1]));
+            const CFeeRate max_raw_tx_fee_rate{ParseFeeRate(self.Arg<UniValue>(1))};
 
             std::vector<CTransactionRef> txns;
             txns.reserve(raw_transactions.size());

test/functional/mempool_accept.py

@@ -90,9 +90,17 @@ def run_test(self):
         txid_in_block = self.wallet.sendrawtransaction(from_node=node, tx_hex=raw_tx_in_block)
         self.generate(node, 1)
         self.mempool_size = 0
+        # Also check feerate. 1BTC/kvB fails
+        assert_raises_rpc_error(-8, "Fee rates larger than or equal to 1BTC/kvB are not accepted", lambda: self.check_mempool_result(
+            result_expected=None,
+            rawtxs=[raw_tx_in_block],
+            maxfeerate=1,
+        ))
+        # ... 0.99 passes
         self.check_mempool_result(
             result_expected=[{'txid': txid_in_block, 'allowed': False, 'reject-reason': 'txn-already-known'}],
             rawtxs=[raw_tx_in_block],
+            maxfeerate=0.99,
         )
 
         self.log.info('A transaction not in the mempool')