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#!/usr/bin/env python3
# Copyright (c) 2015-2020 The Bitcoin Core developers
# Distributed under the MIT software license, see the accompanying
# file COPYING or http://www.opensource.org/licenses/mit-license.php.
"""
Templates for constructing various sorts of invalid transactions.
These templates (or an iterator over all of them) can be reused in different
contexts to test using a number of invalid transaction types.
Hopefully this makes it easier to get coverage of a full variety of tx
validation checks through different interfaces (AcceptBlock, AcceptToMemPool,
etc.) without repeating ourselves.
Invalid tx cases not covered here can be found by running:
$ diff \
<(grep -IREho "bad-txns[a-zA-Z-]+" src | sort -u) \
<(grep -IEho "bad-txns[a-zA-Z-]+" test/functional/data/invalid_txs.py | sort -u)
"""
import abc
from typing import Optional
from test_framework.messages import (
COutPoint,
CTransaction,
CTxIn,
CTxOut,
MAX_MONEY,
)
from test_framework.blocktools import create_tx_with_script, MAX_BLOCK_SIGOPS
from test_framework.script import (
CScript,
OP_0,
OP_2DIV,
OP_2MUL,
OP_AND,
OP_CAT,
OP_CHECKSIG,
OP_DIV,
OP_INVERT,
OP_LEFT,
OP_LSHIFT,
OP_MOD,
OP_MUL,
OP_OR,
OP_RIGHT,
OP_RSHIFT,
OP_SUBSTR,
OP_TRUE,
OP_XOR,
)
from test_framework.script_util import (
script_to_p2sh_script,
)
basic_p2sh = script_to_p2sh_script(CScript([OP_0]))
class BadTxTemplate:
"""Allows simple construction of a certain kind of invalid tx. Base class to be subclassed."""
__metaclass__ = abc.ABCMeta
# The expected error code given by bitcoind upon submission of the tx.
reject_reason: Optional[str] = ""
# Only specified if it differs from mempool acceptance error.
block_reject_reason = ""
# Do we expect to be disconnected after submitting this tx?
expect_disconnect = False
# Is this tx considered valid when included in a block, but not for acceptance into
# the mempool (i.e. does it violate policy but not consensus)?
valid_in_block = False
def __init__(self, *, spend_tx=None, spend_block=None):
self.spend_tx = spend_block.vtx[0] if spend_block else spend_tx
self.spend_avail = sum(o.nValue for o in self.spend_tx.vout)
self.valid_txin = CTxIn(COutPoint(self.spend_tx.sha256, 0), b"", 0xffffffff)
@abc.abstractmethod
def get_tx(self, *args, **kwargs):
"""Return a CTransaction that is invalid per the subclass."""
pass
class OutputMissing(BadTxTemplate):
reject_reason = "bad-txns-vout-empty"
expect_disconnect = True
def get_tx(self):
tx = CTransaction()
tx.vin.append(self.valid_txin)
tx.calc_sha256()
return tx
class InputMissing(BadTxTemplate):
reject_reason = "bad-txns-vin-empty"
expect_disconnect = True
# We use a blank transaction here to make sure
# it is interpreted as a non-witness transaction.
# Otherwise the transaction will fail the
# "surpufluous witness" check during deserialization
# rather than the input count check.
def get_tx(self):
tx = CTransaction()
tx.calc_sha256()
return tx
# The following check prevents exploit of lack of merkle
# tree depth commitment (CVE-2017-12842)
class SizeTooSmall(BadTxTemplate):
reject_reason = "tx-size-small"
expect_disconnect = False
valid_in_block = True
def get_tx(self):
tx = CTransaction()
tx.vin.append(self.valid_txin)
tx.vout.append(CTxOut(0, CScript([OP_TRUE])))
tx.calc_sha256()
return tx
class BadInputOutpointIndex(BadTxTemplate):
# Won't be rejected - nonexistent outpoint index is treated as an orphan since the coins
# database can't distinguish between spent outpoints and outpoints which never existed.
reject_reason = None
expect_disconnect = False
def get_tx(self):
num_indices = len(self.spend_tx.vin)
bad_idx = num_indices + 100
tx = CTransaction()
tx.vin.append(CTxIn(COutPoint(self.spend_tx.sha256, bad_idx), b"", 0xffffffff))
tx.vout.append(CTxOut(0, basic_p2sh))
tx.calc_sha256()
return tx
class DuplicateInput(BadTxTemplate):
reject_reason = 'bad-txns-inputs-duplicate'
expect_disconnect = True
def get_tx(self):
tx = CTransaction()
tx.vin.append(self.valid_txin)
tx.vin.append(self.valid_txin)
tx.vout.append(CTxOut(1, basic_p2sh))
tx.calc_sha256()
return tx
class PrevoutNullInput(BadTxTemplate):
reject_reason = 'bad-txns-prevout-null'
expect_disconnect = True
def get_tx(self):
tx = CTransaction()
tx.vin.append(self.valid_txin)
tx.vin.append(CTxIn(COutPoint(hash=0, n=0xffffffff)))
tx.vout.append(CTxOut(1, basic_p2sh))
tx.calc_sha256()
return tx
class NonexistentInput(BadTxTemplate):
reject_reason = None # Added as an orphan tx.
expect_disconnect = False
def get_tx(self):
tx = CTransaction()
tx.vin.append(CTxIn(COutPoint(self.spend_tx.sha256 + 1, 0), b"", 0xffffffff))
tx.vin.append(self.valid_txin)
tx.vout.append(CTxOut(1, basic_p2sh))
tx.calc_sha256()
return tx
class SpendTooMuch(BadTxTemplate):
reject_reason = 'bad-txns-in-belowout'
expect_disconnect = True
def get_tx(self):
return create_tx_with_script(
self.spend_tx, 0, script_pub_key=basic_p2sh, amount=(self.spend_avail + 1))
class CreateNegative(BadTxTemplate):
reject_reason = 'bad-txns-vout-negative'
expect_disconnect = True
def get_tx(self):
return create_tx_with_script(self.spend_tx, 0, amount=-1)
class CreateTooLarge(BadTxTemplate):
reject_reason = 'bad-txns-vout-toolarge'
expect_disconnect = True
def get_tx(self):
return create_tx_with_script(self.spend_tx, 0, amount=MAX_MONEY + 1)
class CreateSumTooLarge(BadTxTemplate):
reject_reason = 'bad-txns-txouttotal-toolarge'
expect_disconnect = True
def get_tx(self):
tx = create_tx_with_script(self.spend_tx, 0, amount=MAX_MONEY)
tx.vout = [tx.vout[0]] * 2
tx.calc_sha256()
return tx
class InvalidOPIFConstruction(BadTxTemplate):
reject_reason = "mandatory-script-verify-flag-failed (Invalid OP_IF construction)"
expect_disconnect = True
valid_in_block = True
def get_tx(self):
return create_tx_with_script(
self.spend_tx, 0, script_sig=b'\x64' * 35,
amount=(self.spend_avail // 2))
class TooManySigops(BadTxTemplate):
reject_reason = "bad-txns-too-many-sigops"
block_reject_reason = "bad-blk-sigops, out-of-bounds SigOpCount"
expect_disconnect = False
def get_tx(self):
lotsa_checksigs = CScript([OP_CHECKSIG] * (MAX_BLOCK_SIGOPS))
return create_tx_with_script(
self.spend_tx, 0,
script_pub_key=lotsa_checksigs,
amount=1)
def getDisabledOpcodeTemplate(opcode):
""" Creates disabled opcode tx template class"""
def get_tx(self):
tx = CTransaction()
vin = self.valid_txin
vin.scriptSig = CScript([opcode])
tx.vin.append(vin)
tx.vout.append(CTxOut(1, basic_p2sh))
tx.calc_sha256()
return tx
return type('DisabledOpcode_' + str(opcode), (BadTxTemplate,), {
'reject_reason': "disabled opcode",
'expect_disconnect': True,
'get_tx': get_tx,
'valid_in_block' : True
})
# Disabled opcode tx templates (CVE-2010-5137)
DisabledOpcodeTemplates = [getDisabledOpcodeTemplate(opcode) for opcode in [
OP_CAT,
OP_SUBSTR,
OP_LEFT,
OP_RIGHT,
OP_INVERT,
OP_AND,
OP_OR,
OP_XOR,
OP_2MUL,
OP_2DIV,
OP_MUL,
OP_DIV,
OP_MOD,
OP_LSHIFT,
OP_RSHIFT]]
def iter_all_templates():
"""Iterate through all bad transaction template types."""
return BadTxTemplate.__subclasses__()