tverifier: small refactor - electrum - Electrum Bitcoin wallet
HTML git clone https://git.parazyd.org/electrum
DIR Log
DIR Files
DIR Refs
DIR Submodules
---
DIR commit d2abaf54e80621d2a4076c7dd996e08038e9eade
DIR parent 89aa9eb0a7ecdde51ae9e4989d06e14b0122e514
HTML Author: SomberNight <somber.night@protonmail.com>
Date: Mon, 23 Jul 2018 19:55:47 +0200
verifier: small refactor
Diffstat:
M electrum/verifier.py | 64 +++++++++++++++++++------------
1 file changed, 39 insertions(+), 25 deletions(-)
---
DIR diff --git a/electrum/verifier.py b/electrum/verifier.py
t@@ -20,12 +20,18 @@
# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
+
+from typing import Sequence, Optional
+
from .util import ThreadJob, bh2u
from .bitcoin import Hash, hash_decode, hash_encode
from .transaction import Transaction
-class InnerNodeOfSpvProofIsValidTx(Exception): pass
+class MerkleVerificationFailure(Exception): pass
+class MissingBlockHeader(MerkleVerificationFailure): pass
+class MerkleRootMismatch(MerkleVerificationFailure): pass
+class InnerNodeOfSpvProofIsValidTx(MerkleVerificationFailure): pass
class SPV(ThreadJob):
t@@ -85,28 +91,17 @@ class SPV(ThreadJob):
tx_hash = params[0]
tx_height = merkle.get('block_height')
pos = merkle.get('pos')
- try:
- merkle_root = self.hash_merkle_root(merkle['merkle'], tx_hash, pos)
- except InnerNodeOfSpvProofIsValidTx:
- self.print_error("merkle verification failed for {} (inner node looks like tx)"
- .format(tx_hash))
- return
+ merkle_branch = merkle.get('merkle')
header = self.network.blockchain().read_header(tx_height)
- # FIXME: if verification fails below,
- # we should make a fresh connection to a server to
- # recover from this, as this TX will now never verify
- if not header:
- self.print_error(
- "merkle verification failed for {} (missing header {})"
- .format(tx_hash, tx_height))
- return
- if header.get('merkle_root') != merkle_root:
- self.print_error(
- "merkle verification failed for {} (merkle root mismatch {} != {})"
- .format(tx_hash, header.get('merkle_root'), merkle_root))
+ try:
+ verify_tx_is_in_block(tx_hash, merkle_branch, pos, header, tx_height)
+ except MerkleVerificationFailure as e:
+ self.print_error(str(e))
+ # FIXME: we should make a fresh connection to a server
+ # to recover from this, as this TX will now never verify
return
# we passed all the tests
- self.merkle_roots[tx_hash] = merkle_root
+ self.merkle_roots[tx_hash] = header.get('merkle_root')
try:
# note: we could pop in the beginning, but then we would request
# this proof again in case of verification failure from the same server
t@@ -118,11 +113,17 @@ class SPV(ThreadJob):
self.wallet.save_verified_tx(write=True)
@classmethod
- def hash_merkle_root(cls, merkle_s, target_hash, pos):
- h = hash_decode(target_hash)
- for i in range(len(merkle_s)):
- item = merkle_s[i]
- h = Hash(hash_decode(item) + h) if ((pos >> i) & 1) else Hash(h + hash_decode(item))
+ def hash_merkle_root(cls, merkle_branch: Sequence[str], tx_hash: str, leaf_pos_in_tree: int):
+ """Return calculated merkle root."""
+ try:
+ h = hash_decode(tx_hash)
+ merkle_branch_bytes = [hash_decode(item) for item in merkle_branch]
+ int(leaf_pos_in_tree) # raise if invalid
+ except Exception as e:
+ raise MerkleVerificationFailure(e)
+
+ for i, item in enumerate(merkle_branch_bytes):
+ h = Hash(item + h) if ((leaf_pos_in_tree >> i) & 1) else Hash(h + item)
cls._raise_if_valid_tx(bh2u(h))
return hash_encode(h)
t@@ -156,3 +157,16 @@ class SPV(ThreadJob):
def is_up_to_date(self):
return not self.requested_merkle
+
+
+def verify_tx_is_in_block(tx_hash: str, merkle_branch: Sequence[str],
+ leaf_pos_in_tree: int, block_header: Optional[dict],
+ block_height: int) -> None:
+ """Raise MerkleVerificationFailure if verification fails."""
+ if not block_header:
+ raise MissingBlockHeader("merkle verification failed for {} (missing header {})"
+ .format(tx_hash, block_height))
+ calc_merkle_root = SPV.hash_merkle_root(merkle_branch, tx_hash, leaf_pos_in_tree)
+ if block_header.get('merkle_root') != calc_merkle_root:
+ raise MerkleRootMismatch("merkle verification failed for {} ({} != {})".format(
+ tx_hash, block_header.get('merkle_root'), calc_merkle_root))