electrum

Electrum Bitcoin wallet
git clone https://git.parazyd.org/electrum
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commit 28572197fbdbc39d35f2e520b7deac670430845a
parent e9251c8e592a22fd11ef3cd1fdf7590515809925
Author: ghost43 <somber.night@protonmail.com>
Date:   Tue, 25 Feb 2020 19:56:27 +0000

Merge pull request #5992 from zebra-lucky/fix_spv_hash_merkle_root

fix SPV.hash_merkle_root, add tests/test_verifier.py
Diffstat:
Aelectrum/tests/test_verifier.py | 50++++++++++++++++++++++++++++++++++++++++++++++++++
Melectrum/verifier.py | 5+++--
2 files changed, 53 insertions(+), 2 deletions(-)

diff --git a/electrum/tests/test_verifier.py b/electrum/tests/test_verifier.py @@ -0,0 +1,50 @@ +# -*- coding: utf-8 -*- + +from electrum.bitcoin import hash_encode +from electrum.transaction import Transaction +from electrum.util import bfh +from electrum.verifier import SPV, InnerNodeOfSpvProofIsValidTx + +from . import TestCaseForTestnet + + +MERKLE_BRANCH = [ + 'f2994fd4546086b21b4916b76cf901afb5c4db1c3ecbfc91d6f4cae1186dfe12', + '6b65935528311901c7acda7db817bd6e3ce2f05d1c62c385b7caadb65fac7520'] + +MERKLE_ROOT = '11dbac015b6969ea75509dd1250f33c04ec4d562c2d895de139a65f62f808254' + +VALID_64_BYTE_TX = ('0200000001cb659c5528311901a7aada7db817bd6e3ce2f05d1c62c385b7caad' + 'b65fac75201234000000fabcdefa01abcd1234010000000405060708fabcdefa') +assert len(VALID_64_BYTE_TX) == 128 + + +class VerifierTestCase(TestCaseForTestnet): + # these tests are regarding the attack described in + # https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2018-June/016105.html + + def test_verify_ok_t_tx(self): + """Actually mined 64 byte tx should not raise.""" + t_tx = Transaction(VALID_64_BYTE_TX) + t_tx_hash = t_tx.txid() + self.assertEqual(MERKLE_ROOT, SPV.hash_merkle_root(MERKLE_BRANCH, t_tx_hash, 3)) + + def test_verify_fail_f_tx_odd(self): + """Raise if inner node of merkle branch is valid tx. ('odd' fake leaf position)""" + # first 32 bytes of T encoded as hash + fake_branch_node = hash_encode(bfh(VALID_64_BYTE_TX[:64])) + fake_mbranch = [fake_branch_node] + MERKLE_BRANCH + # last 32 bytes of T encoded as hash + f_tx_hash = hash_encode(bfh(VALID_64_BYTE_TX[64:])) + with self.assertRaises(InnerNodeOfSpvProofIsValidTx): + SPV.hash_merkle_root(fake_mbranch, f_tx_hash, 7) + + def test_verify_fail_f_tx_even(self): + """Raise if inner node of merkle branch is valid tx. ('even' fake leaf position)""" + # last 32 bytes of T encoded as hash + fake_branch_node = hash_encode(bfh(VALID_64_BYTE_TX[64:])) + fake_mbranch = [fake_branch_node] + MERKLE_BRANCH + # first 32 bytes of T encoded as hash + f_tx_hash = hash_encode(bfh(VALID_64_BYTE_TX[:64])) + with self.assertRaises(InnerNodeOfSpvProofIsValidTx): + SPV.hash_merkle_root(fake_mbranch, f_tx_hash, 6) diff --git a/electrum/verifier.py b/electrum/verifier.py @@ -149,9 +149,10 @@ class SPV(NetworkJobOnDefaultServer): for item in merkle_branch_bytes: if len(item) != 32: raise MerkleVerificationFailure('all merkle branch items have to 32 bytes long') - h = sha256d(item + h) if (index & 1) else sha256d(h + item) + inner_node = (item + h) if (index & 1) else (h + item) + cls._raise_if_valid_tx(bh2u(inner_node)) + h = sha256d(inner_node) index >>= 1 - cls._raise_if_valid_tx(bh2u(h)) if index != 0: raise MerkleVerificationFailure(f'leaf_pos_in_tree too large for branch') return hash_encode(h)