Merge #538: Enforce coinbase maturity on bitcoin peg-ins

5acc42e feature_fedpeg.py: remove the spam output (Gregory Sanders)
870e416 Enforce coinbase maturity on bitcoin peg-ins (Gregory Sanders)

Pull request description:

  resolves #14

  Technically a softfork but not really since the elements chain would eventually become valid anyways.

Tree-SHA512: bfdf404f7056e6b16adde3a82b0e11839b921fd08063ae6415d207b553e1a19c5f5a76cb308af1ca63164c001eb59b5874fe33160f7bf87061a6a4a507aa9241

src/pegins.cpp

@@ -189,7 +189,7 @@ static bool CheckPeginTx(const std::vector<unsigned char>& tx_data, T& pegtx, co
 }
 
 template<typename T>
-static bool GetBlockAndTxFromMerkleBlock(uint256& block_hash, uint256& tx_hash, T& merkle_block, const std::vector<unsigned char>& merkle_block_raw)
+static bool GetBlockAndTxFromMerkleBlock(uint256& block_hash, uint256& tx_hash, unsigned int& tx_index, T& merkle_block, const std::vector<unsigned char>& merkle_block_raw)
 {
     try {
         std::vector<uint256> tx_hashes;
@@ -205,6 +205,7 @@ static bool GetBlockAndTxFromMerkleBlock(uint256& block_hash, uint256& tx_hash,
             return false;
         }
         tx_hash = tx_hashes[0];
+        tx_index = tx_indices[0];
     } catch (std::exception& e) {
         // Invalid encoding of merkle block
         return false;
@@ -295,10 +296,11 @@ bool IsValidPeginWitness(const CScriptWitness& pegin_witness, const COutPoint& p
     uint256 block_hash;
     uint256 tx_hash;
     int num_txs;
+    unsigned int tx_index = 0;
     // Get txout proof
     if (Params().GetConsensus().ParentChainHasPow()) {
         Sidechain::Bitcoin::CMerkleBlock merkle_block_pow;
-        if (!GetBlockAndTxFromMerkleBlock(block_hash, tx_hash, merkle_block_pow, stack[5])) {
+        if (!GetBlockAndTxFromMerkleBlock(block_hash, tx_hash, tx_index, merkle_block_pow, stack[5])) {
             err_msg = "Could not extract block and tx from merkleblock.";
             return false;
         }
@@ -316,7 +318,7 @@ bool IsValidPeginWitness(const CScriptWitness& pegin_witness, const COutPoint& p
         num_txs = merkle_block_pow.txn.GetNumTransactions();
     } else {
         CMerkleBlock merkle_block;
-        if (!GetBlockAndTxFromMerkleBlock(block_hash, tx_hash, merkle_block, stack[5])) {
+        if (!GetBlockAndTxFromMerkleBlock(block_hash, tx_hash, tx_index, merkle_block, stack[5])) {
             err_msg = "Could not extract block and tx from merkleblock.";
             return false;
         }
@@ -354,7 +356,13 @@ bool IsValidPeginWitness(const CScriptWitness& pegin_witness, const COutPoint& p
 
     // Finally, validate peg-in via rpc call
     if (check_depth && gArgs.GetBoolArg("-validatepegin", Params().GetConsensus().has_parent_chain)) {
-        if (!IsConfirmedBitcoinBlock(block_hash, Params().GetConsensus().pegin_min_depth, num_txs)) {
+        unsigned int required_depth = Params().GetConsensus().pegin_min_depth;
+        // Don't allow coinbase output claims before coinbase maturity
+        if (tx_index == 0) {
+            required_depth = std::max(required_depth, (unsigned int)COINBASE_MATURITY);
+        }
+        LogPrintf("Required depth: %d\n", required_depth);
+        if (!IsConfirmedBitcoinBlock(block_hash, required_depth, num_txs)) {
             err_msg = "Needs more confirmations.";
             return false;
         }

src/wallet/rpcwallet.cpp

@@ -5240,7 +5240,11 @@ static UniValue createrawpegin(const JSONRPCRequest& request, T_tx_ref& txBTCRef
 
     // Additional block lee-way to avoid bitcoin block races
     if (gArgs.GetBoolArg("-validatepegin", Params().GetConsensus().has_parent_chain)) {
-        ret.pushKV("mature", IsConfirmedBitcoinBlock(merkleBlock.header.GetHash(), Params().GetConsensus().pegin_min_depth+2, merkleBlock.txn.GetNumTransactions()));
+        unsigned int required_depth = Params().GetConsensus().pegin_min_depth + 2;
+        if (txIndices[0] == 0) {
+            required_depth = std::max(required_depth, (unsigned int)COINBASE_MATURITY+2);
+        }
+        ret.pushKV("mature", IsConfirmedBitcoinBlock(merkleBlock.header.GetHash(), required_depth, merkleBlock.txn.GetNumTransactions()));
     }
 
     return ret;

test/functional/feature_fedpeg.py

@@ -10,6 +10,8 @@
     get_datadir_path,
     rpc_port,
     p2p_port,
+    assert_raises_rpc_error,
+    assert_equal,
 )
 from decimal import Decimal
 
@@ -62,9 +64,10 @@ def setup_network(self, split=False):
             else:
                 extra_args.extend([
                     "-validatepegin=0",
-                    "-initialfreecoins=2100000000000000",
+                    "-initialfreecoins=0",
                     "-anyonecanspendaremine",
                     "-signblockscript=51", # OP_TRUE
+                    '-con_blocksubsidy=5000000000',
                 ])
 
             self.add_nodes(1, [extra_args], chain=[parent_chain], binary=parent_binary, chain_in_args=[not self.options.parent_bitcoin])
@@ -73,7 +76,6 @@ def setup_network(self, split=False):
 
         connect_nodes_bi(self.nodes, 0, 1)
         self.parentgenesisblockhash = self.nodes[0].getblockhash(0)
-        print('parentgenesisblockhash', self.parentgenesisblockhash)
         if not self.options.parent_bitcoin:
             parent_pegged_asset = self.nodes[0].getsidechaininfo()['pegged_asset']
 
@@ -158,24 +160,20 @@ def run_test(self):
 
         addrs = sidechain.getpeginaddress()
         addr = addrs["mainchain_address"]
-        print('addrs', addrs)
-        print(parent.getaddressinfo(addr))
         txid1 = parent.sendtoaddress(addr, 24)
         # 10+2 confirms required to get into mempool and confirm
         parent.generate(1)
         time.sleep(2)
         proof = parent.gettxoutproof([txid1])
 
         raw = parent.getrawtransaction(txid1)
-        print('raw', parent.getrawtransaction(txid1, True))
 
-        print("Attempting peg-in")
+        print("Attempting peg-ins")
         # First attempt fails the consensus check but gives useful result
         try:
             pegtxid = sidechain.claimpegin(raw, proof)
             raise Exception("Peg-in should not be mature enough yet, need another block.")
         except JSONRPCException as e:
-            print('RPC ERROR:', e.error['message'])
             assert("Peg-in Bitcoin transaction needs more confirmations to be sent." in e.error["message"])
 
         # Second attempt simply doesn't hit mempool bar
@@ -184,14 +182,12 @@ def run_test(self):
             pegtxid = sidechain.claimpegin(raw, proof)
             raise Exception("Peg-in should not be mature enough yet, need another block.")
         except JSONRPCException as e:
-            print('RPC ERROR:', e.error['message'])
             assert("Peg-in Bitcoin transaction needs more confirmations to be sent." in e.error["message"])
 
         try:
             pegtxid = sidechain.createrawpegin(raw, proof, 'AEIOU')
             raise Exception("Peg-in with non-hex claim_script should fail.")
         except JSONRPCException as e:
-            print('RPC ERROR:', e.error['message'])
             assert("Given claim_script is not hex." in e.error["message"])
 
         # Should fail due to non-matching wallet address
@@ -200,7 +196,6 @@ def run_test(self):
             pegtxid = sidechain.claimpegin(raw, proof, scriptpubkey)
             raise Exception("Peg-in with non-matching claim_script should fail.")
         except JSONRPCException as e:
-            print('RPC ERROR:', e.error['message'])
             assert("Given claim_script does not match the given Bitcoin transaction." in e.error["message"])
 
         # 12 confirms allows in mempool
@@ -219,7 +214,6 @@ def run_test(self):
 
         tx1 = sidechain.gettransaction(pegtxid1)
 
-        print('tx1', tx1)
         if "confirmations" in tx1 and tx1["confirmations"] == 6:
             print("Peg-in is confirmed: Success!")
         else:
@@ -233,7 +227,6 @@ def run_test(self):
         vsize = decoded["vsize"]
         fee_output = decoded["vout"][1]
         fallbackfee_pervbyte = Decimal("0.00001")/Decimal("1000")
-        print("fee_output", fee_output)
         assert fee_output["scriptPubKey"]["type"] == "fee"
         assert fee_output["value"] >= fallbackfee_pervbyte*vsize
 
@@ -252,7 +245,7 @@ def run_test(self):
         # Do multiple claims in mempool
         n_claims = 6
 
-        print("Flooding mempool with many small claims")
+        print("Flooding mempool with a few claims")
         pegtxs = []
         sidechain.generate(101)
 
@@ -352,7 +345,6 @@ def run_test(self):
 
         print("Restarting parent2")
         self.start_node(1)
-        #parent2 = self.nodes[1]
         connect_nodes_bi(self.nodes, 0, 1)
 
         # Don't make a block, race condition when pegin-invalid block
@@ -401,10 +393,41 @@ def run_test(self):
         # Make sure balance went down
         assert(bal_2 + 1 < bal_1)
 
+        # Send rest of coins using subtractfee from output arg
         sidechain.sendtomainchain(some_btc_addr, bal_2, True)
 
         assert(sidechain.getwalletinfo()["balance"]['bitcoin'] == 0)
 
+        print('Test coinbase peg-in maturity rules')
+
+        # Have bitcoin output go directly into a claim output
+        pegin_info = sidechain.getpeginaddress()
+        mainchain_addr = pegin_info["mainchain_address"]
+        # Watch the address so we can get tx without txindex
+        parent.importaddress(mainchain_addr)
+        claim_block = parent.generatetoaddress(50, mainchain_addr)[0]
+        block_coinbase = parent.getblock(claim_block, 2)["tx"][0]
+        claim_txid = block_coinbase["txid"]
+        claim_tx = block_coinbase["hex"]
+        claim_proof = parent.gettxoutproof([claim_txid], claim_block)
+
+        # Can't claim something even though it has 50 confirms since it's coinbase
+        assert_raises_rpc_error(-8, "Peg-in Bitcoin transaction needs more confirmations to be sent.", sidechain.claimpegin, claim_tx, claim_proof)
+        # If done via raw API, still doesn't work
+        coinbase_pegin = sidechain.createrawpegin(claim_tx, claim_proof)
+        assert_equal(coinbase_pegin["mature"], False)
+        signed_pegin = sidechain.signrawtransactionwithwallet(coinbase_pegin["hex"])["hex"]
+        assert_raises_rpc_error(-26, "bad-pegin-witness, Needs more confirmations.", sidechain.sendrawtransaction, signed_pegin)
+
+        # 50 more blocks to allow wallet to make it succeed by relay and consensus
+        parent.generatetoaddress(50, parent.getnewaddress())
+        # Wallet still doesn't want to for 2 more confirms
+        assert_equal(sidechain.createrawpegin(claim_tx, claim_proof)["mature"], False)
+        # But we can just shoot it off
+        claim_txid = sidechain.sendrawtransaction(signed_pegin)
+        sidechain.generatetoaddress(1, sidechain.getnewaddress())
+        assert_equal(sidechain.gettransaction(claim_txid)["confirmations"], 1)
+
         print('Success!')
 
         # Manually stop sidechains first, then the parent chains.