Merge #8312: Fix mempool DoS vulnerability from malleated transactions

46c9620 Test that unnecessary witnesses can't be used for mempool DoS (Suhas Daftuar)
bb66a11 Fix DoS vulnerability in mempool acceptance (Suhas Daftuar)
This commit is contained in:
Wladimir J. van der Laan 2016-07-14 08:20:38 +02:00
commit ca40ef6029
No known key found for this signature in database
GPG key ID: 74810B012346C9A6
2 changed files with 56 additions and 8 deletions

View file

@ -43,6 +43,7 @@ class TestNode(NodeConnCB):
self.last_pong = msg_pong(0)
self.sleep_time = 0.05
self.getdataset = set()
self.last_reject = None
def add_connection(self, conn):
self.connection = conn
@ -68,7 +69,7 @@ class TestNode(NodeConnCB):
def on_reject(self, conn, message):
self.last_reject = message
#print message
#print (message)
# Syncing helpers
def sync(self, test_function, timeout=60):
@ -136,13 +137,17 @@ class TestNode(NodeConnCB):
self.wait_for_block(blockhash, timeout)
return self.last_block
def test_transaction_acceptance(self, tx, with_witness, accepted):
def test_transaction_acceptance(self, tx, with_witness, accepted, reason=None):
tx_message = msg_tx(tx)
if with_witness:
tx_message = msg_witness_tx(tx)
self.send_message(tx_message)
self.sync_with_ping()
assert_equal(tx.hash in self.connection.rpc.getrawmempool(), accepted)
if (reason != None and not accepted):
# Check the rejection reason as well.
with mininode_lock:
assert_equal(self.last_reject.reason, reason)
# Test whether a witness block had the correct effect on the tip
def test_witness_block(self, block, accepted, with_witness=True):
@ -277,9 +282,52 @@ class SegWitTest(BitcoinTestFramework):
self.test_node.sync_with_ping()
assert_equal(self.nodes[0].getbestblockhash(), block.hash)
sync_blocks(self.nodes)
# Create a p2sh output -- this is so we can pass the standardness
# rules (an anyone-can-spend OP_TRUE would be rejected, if not wrapped
# in P2SH).
p2sh_program = CScript([OP_TRUE])
p2sh_pubkey = hash160(p2sh_program)
scriptPubKey = CScript([OP_HASH160, p2sh_pubkey, OP_EQUAL])
# Now check that unnecessary witnesses can't be used to blind a node
# to a transaction, eg by violating standardness checks.
tx2 = CTransaction()
tx2.vin.append(CTxIn(COutPoint(tx.sha256, 0), b""))
tx2.vout.append(CTxOut(tx.vout[0].nValue-1000, scriptPubKey))
tx2.rehash()
self.test_node.test_transaction_acceptance(tx2, False, True)
self.nodes[0].generate(1)
sync_blocks(self.nodes)
# We'll add an unnecessary witness to this transaction that would cause
# it to be too large according to IsStandard.
tx3 = CTransaction()
tx3.vin.append(CTxIn(COutPoint(tx2.sha256, 0), CScript([p2sh_program])))
tx3.vout.append(CTxOut(tx2.vout[0].nValue-1000, scriptPubKey))
tx3.wit.vtxinwit.append(CTxinWitness())
tx3.wit.vtxinwit[0].scriptWitness.stack = [b'a'*400000]
tx3.rehash()
self.std_node.test_transaction_acceptance(tx3, True, False, b'no-witness-yet')
# If we send without witness, it should be accepted.
self.std_node.test_transaction_acceptance(tx3, False, True)
# Now create a new anyone-can-spend utxo for the next test.
tx4 = CTransaction()
tx4.vin.append(CTxIn(COutPoint(tx3.sha256, 0), CScript([p2sh_program])))
tx4.vout.append(CTxOut(tx3.vout[0].nValue-1000, CScript([OP_TRUE])))
tx4.rehash()
self.test_node.test_transaction_acceptance(tx3, False, True)
self.test_node.test_transaction_acceptance(tx4, False, True)
self.nodes[0].generate(1)
sync_blocks(self.nodes)
# Update our utxo list; we spent the first entry.
self.utxo.pop(0)
self.utxo.append(UTXO(tx.sha256, 0, tx.vout[0].nValue))
self.utxo.append(UTXO(tx4.sha256, 0, tx4.vout[0].nValue))
# Mine enough blocks for segwit's vb state to be 'started'.

View file

@ -1132,11 +1132,6 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const C
if (tx.IsCoinBase())
return state.DoS(100, false, REJECT_INVALID, "coinbase");
// Rather not work on nonstandard transactions (unless -testnet/-regtest)
string reason;
if (fRequireStandard && !IsStandardTx(tx, reason))
return state.DoS(0, false, REJECT_NONSTANDARD, reason);
// Don't relay version 2 transactions until CSV is active, and we can be
// sure that such transactions will be mined (unless we're on
// -testnet/-regtest).
@ -1150,6 +1145,11 @@ bool AcceptToMemoryPoolWorker(CTxMemPool& pool, CValidationState& state, const C
return state.DoS(0, false, REJECT_NONSTANDARD, "no-witness-yet", true);
}
// Rather not work on nonstandard transactions (unless -testnet/-regtest)
string reason;
if (fRequireStandard && !IsStandardTx(tx, reason))
return state.DoS(0, false, REJECT_NONSTANDARD, reason);
// Only accept nLockTime-using transactions that can be mined in the next
// block; we don't want our mempool filled up with transactions that can't
// be mined yet.