1  #!/usr/bin/env python3
  2  # Copyright (c) 2023-present The Bitcoin Core developers
  3  # Distributed under the MIT software license, see the accompanying
  4  # file COPYING or http://www.opensource.org/licenses/mit-license.php.
  5  """Test sigop limit mempool policy (`-bytespersigop` parameter)"""
  6  from copy import deepcopy
  7  from decimal import Decimal
  8  from math import ceil
  9  
 10  from test_framework.messages import (
 11      COutPoint,
 12      CTransaction,
 13      CTxIn,
 14      CTxInWitness,
 15      CTxOut,
 16      WITNESS_SCALE_FACTOR,
 17      tx_from_hex,
 18  )
 19  from test_framework.script import (
 20      CScript,
 21      OP_2DUP,
 22      OP_CHECKMULTISIG,
 23      OP_CHECKSIG,
 24      OP_DROP,
 25      OP_ENDIF,
 26      OP_FALSE,
 27      OP_IF,
 28      OP_NOT,
 29      OP_RETURN,
 30      OP_TRUE,
 31  )
 32  from test_framework.script_util import (
 33      keys_to_multisig_script,
 34      script_to_p2wsh_script,
 35      script_to_p2sh_script,
 36      MAX_STD_LEGACY_SIGOPS,
 37      MAX_STD_P2SH_SIGOPS,
 38  )
 39  from test_framework.test_framework import BitcoinTestFramework
 40  from test_framework.util import (
 41      assert_equal,
 42      assert_greater_than,
 43      assert_greater_than_or_equal,
 44      assert_raises_rpc_error,
 45  )
 46  from test_framework.wallet import MiniWallet
 47  from test_framework.wallet_util import generate_keypair
 48  
 49  DEFAULT_BYTES_PER_SIGOP = 20  # default setting
 50  MAX_PUBKEYS_PER_MULTISIG = 20
 51  
 52  class BytesPerSigOpTest(BitcoinTestFramework):
 53      def set_test_params(self):
 54          self.num_nodes = 1
 55  
 56      def create_p2wsh_spending_tx(self, witness_script, output_script):
 57          """Create a 1-input-1-output P2WSH spending transaction with only the
 58             witness script in the witness stack and the given output script."""
 59          # create P2WSH address and fund it via MiniWallet first
 60          fund = self.wallet.send_to(
 61              from_node=self.nodes[0],
 62              scriptPubKey=script_to_p2wsh_script(witness_script),
 63              amount=1000000,
 64          )
 65  
 66          # create spending transaction
 67          tx = CTransaction()
 68          tx.vin = [CTxIn(COutPoint(int(fund["txid"], 16), fund["sent_vout"]))]
 69          tx.wit.vtxinwit = [CTxInWitness()]
 70          tx.wit.vtxinwit[0].scriptWitness.stack = [bytes(witness_script)]
 71          tx.vout = [CTxOut(500000, output_script)]
 72          return tx
 73  
 74      def test_sigops_limit(self, bytes_per_sigop, num_sigops):
 75          sigop_equivalent_vsize = ceil(num_sigops * bytes_per_sigop / WITNESS_SCALE_FACTOR)
 76          self.log.info(f"- {num_sigops} sigops (equivalent size of {sigop_equivalent_vsize} vbytes)")
 77  
 78          # create a template tx with the specified sigop cost in the witness script
 79          # (note that the sigops count even though being in a branch that's not executed)
 80          num_multisigops = num_sigops // 20
 81          num_singlesigops = num_sigops % 20
 82          witness_script = CScript(
 83              [OP_FALSE, OP_IF] +
 84              [OP_CHECKMULTISIG]*num_multisigops +
 85              [OP_CHECKSIG]*num_singlesigops +
 86              [OP_ENDIF, OP_TRUE]
 87          )
 88          # use a 256-byte data-push as lower bound in the output script, in order
 89          # to avoid having to compensate for tx size changes caused by varying
 90          # length serialization sizes (both for scriptPubKey and data-push lengths)
 91          tx = self.create_p2wsh_spending_tx(witness_script, CScript([OP_RETURN, b'X'*256]))
 92  
 93          # bump the tx to reach the sigop-limit equivalent size by padding the datacarrier output
 94          assert_greater_than_or_equal(sigop_equivalent_vsize, tx.get_vsize())
 95          vsize_to_pad = sigop_equivalent_vsize - tx.get_vsize()
 96          tx.vout[0].scriptPubKey = CScript([OP_RETURN, b'X'*(256+vsize_to_pad)])
 97          assert_equal(sigop_equivalent_vsize, tx.get_vsize())
 98  
 99          res = self.nodes[0].testmempoolaccept([tx.serialize().hex()])[0]
100          assert_equal(res['allowed'], True)
101          assert_equal(res['vsize'], sigop_equivalent_vsize)
102  
103          # increase the tx's vsize to be right above the sigop-limit equivalent size
104          # => tx's vsize in mempool should also grow accordingly
105          tx.vout[0].scriptPubKey = CScript([OP_RETURN, b'X'*(256+vsize_to_pad+1)])
106          res = self.nodes[0].testmempoolaccept([tx.serialize().hex()])[0]
107          assert_equal(res['allowed'], True)
108          assert_equal(res['vsize'], sigop_equivalent_vsize+1)
109  
110          # decrease the tx's vsize to be right below the sigop-limit equivalent size
111          # => tx's vsize in mempool should stick at the sigop-limit equivalent
112          # bytes level, as it is higher than the tx's serialized vsize
113          # (the maximum of both is taken)
114          tx.vout[0].scriptPubKey = CScript([OP_RETURN, b'X'*(256+vsize_to_pad-1)])
115          res = self.nodes[0].testmempoolaccept([tx.serialize().hex()])[0]
116          assert_equal(res['allowed'], True)
117          assert_equal(res['vsize'], sigop_equivalent_vsize)
118  
119          # check that the ancestor and descendant size calculations in the mempool
120          # also use the same max(sigop_equivalent_vsize, serialized_vsize) logic
121          # (to keep it simple, we only test the case here where the sigop vsize
122          # is much larger than the serialized vsize, i.e. we create a small child
123          # tx by getting rid of the large padding output)
124          tx.vout[0].scriptPubKey = CScript([OP_RETURN, b'test123'])
125          assert_greater_than(sigop_equivalent_vsize, tx.get_vsize())
126          self.nodes[0].sendrawtransaction(hexstring=tx.serialize().hex(), maxburnamount='1.0')
127  
128          # fetch parent tx, which doesn't contain any sigops
129          parent_txid = tx.vin[0].prevout.hash.to_bytes(32, 'big').hex()
130          parent_tx = tx_from_hex(self.nodes[0].getrawtransaction(txid=parent_txid))
131  
132          entry_child = self.nodes[0].getmempoolentry(tx.txid_hex)
133          assert_equal(entry_child['descendantcount'], 1)
134          assert_equal(entry_child['descendantsize'], sigop_equivalent_vsize)
135          assert_equal(entry_child['ancestorcount'], 2)
136          assert_equal(entry_child['ancestorsize'], sigop_equivalent_vsize + parent_tx.get_vsize())
137  
138          entry_parent = self.nodes[0].getmempoolentry(parent_tx.txid_hex)
139          assert_equal(entry_parent['ancestorcount'], 1)
140          assert_equal(entry_parent['ancestorsize'], parent_tx.get_vsize())
141          assert_equal(entry_parent['descendantcount'], 2)
142          assert_equal(entry_parent['descendantsize'], parent_tx.get_vsize() + sigop_equivalent_vsize)
143  
144      def test_sigops_package(self):
145          self.log.info("Test a overly-large sigops-vbyte hits package limits")
146          # Make a 2-transaction package which fails vbyte checks even though
147          # separately they would work.
148          self.restart_node(0, extra_args=["-bytespersigop=5000","-permitbaremultisig=1"])
149  
150          def create_bare_multisig_tx(utxo_to_spend=None):
151              _, pubkey = generate_keypair()
152              amount_for_bare = 50000
153              tx_dict = self.wallet.create_self_transfer(fee=Decimal("3"), utxo_to_spend=utxo_to_spend)
154              tx_utxo = tx_dict["new_utxo"]
155              tx = tx_dict["tx"]
156              tx.vout.append(CTxOut(amount_for_bare, keys_to_multisig_script([pubkey], k=1)))
157              tx.vout[0].nValue -= amount_for_bare
158              tx_utxo["txid"] = tx.txid_hex
159              tx_utxo["value"] -= Decimal("0.00005000")
160              return (tx_utxo, tx)
161  
162          tx_parent_utxo, tx_parent = create_bare_multisig_tx()
163          _tx_child_utxo, tx_child = create_bare_multisig_tx(tx_parent_utxo)
164  
165          # Separately, the parent tx is ok
166          parent_individual_testres = self.nodes[0].testmempoolaccept([tx_parent.serialize().hex()])[0]
167          assert parent_individual_testres["allowed"]
168          max_multisig_vsize = MAX_PUBKEYS_PER_MULTISIG * 5000
169          assert_equal(parent_individual_testres["vsize"], max_multisig_vsize)
170  
171          # But together, it's exceeding limits in the *package* context. If sigops adjusted vsize wasn't being checked
172          # here, it would get further in validation and give too-large-cluster error instead.
173          packet_test = self.nodes[0].testmempoolaccept([tx_parent.serialize().hex(), tx_child.serialize().hex()])
174          expected_package_error = "too-large-cluster"
175          assert_equal([x["package-error"] for x in packet_test], [expected_package_error] * 2)
176  
177          # When we actually try to submit, the parent makes it into the mempool, but the child would exceed cluster vsize limits
178          res = self.nodes[0].submitpackage([tx_parent.serialize().hex(), tx_child.serialize().hex()])
179          assert "too-large-cluster" in res["tx-results"][tx_child.wtxid_hex]["error"]
180          assert tx_parent.txid_hex in self.nodes[0].getrawmempool()
181  
182          # Transactions are tiny in weight
183          assert_greater_than(2000, tx_parent.get_weight() + tx_child.get_weight())
184  
185      def test_legacy_sigops_stdness(self):
186          self.log.info("Test a transaction with too many legacy sigops in its inputs is non-standard.")
187  
188          # Restart with the default settings
189          self.restart_node(0)
190  
191          # Create a P2SH script with 15 sigops.
192          _, dummy_pubkey = generate_keypair()
193          packed_redeem_script = [dummy_pubkey]
194          for _ in range(MAX_STD_P2SH_SIGOPS - 1):
195              packed_redeem_script += [OP_2DUP, OP_CHECKSIG, OP_DROP]
196          packed_redeem_script = CScript(packed_redeem_script + [OP_CHECKSIG, OP_NOT])
197          packed_p2sh_script = script_to_p2sh_script(packed_redeem_script)
198  
199          # Create enough outputs to reach the sigops limit when spending them all at once.
200          outpoints = []
201          for _ in range(int(MAX_STD_LEGACY_SIGOPS / MAX_STD_P2SH_SIGOPS) + 1):
202              res = self.wallet.send_to(from_node=self.nodes[0], scriptPubKey=packed_p2sh_script, amount=1_000)
203              txid = int.from_bytes(bytes.fromhex(res["txid"]), byteorder="big")
204              outpoints.append(COutPoint(txid, res["sent_vout"]))
205          self.generate(self.nodes[0], 1)
206  
207          # Spending all these outputs at once accounts for 2505 legacy sigops and is non-standard.
208          nonstd_tx = CTransaction()
209          nonstd_tx.vin = [CTxIn(op, CScript([b"", packed_redeem_script])) for op in outpoints]
210          nonstd_tx.vout = [CTxOut(0, CScript([OP_RETURN, b""]))]
211          assert_raises_rpc_error(-26, "bad-txns-nonstandard-inputs", self.nodes[0].sendrawtransaction, nonstd_tx.serialize().hex())
212  
213          # Spending one less accounts for 2490 legacy sigops and is standard.
214          std_tx = deepcopy(nonstd_tx)
215          std_tx.vin.pop()
216          self.nodes[0].sendrawtransaction(std_tx.serialize().hex())
217  
218          # Make sure the original, non-standard, transaction can be mined.
219          self.generateblock(self.nodes[0], output="raw(42)", transactions=[nonstd_tx.serialize().hex()])
220  
221      def run_test(self):
222          self.wallet = MiniWallet(self.nodes[0])
223  
224          for bytes_per_sigop in (DEFAULT_BYTES_PER_SIGOP, 43, 81, 165, 327, 649, 1072):
225              if bytes_per_sigop == DEFAULT_BYTES_PER_SIGOP:
226                  self.log.info(f"Test default sigops limit setting ({bytes_per_sigop} bytes per sigop)...")
227              else:
228                  bytespersigop_parameter = f"-bytespersigop={bytes_per_sigop}"
229                  self.log.info(f"Test sigops limit setting {bytespersigop_parameter}...")
230                  self.restart_node(0, extra_args=[bytespersigop_parameter])
231  
232              for num_sigops in (69, 101, 142, 183, 222):
233                  self.test_sigops_limit(bytes_per_sigop, num_sigops)
234  
235              self.generate(self.wallet, 1)
236  
237          self.test_sigops_package()
238          self.test_legacy_sigops_stdness()
239  
240  
241  if __name__ == '__main__':
242      BytesPerSigOpTest(__file__).main()