From c8f996e29ffd7055bc6521ea610fc12ff50502e5 Mon Sep 17 00:00:00 2001 From: Mark Haines Date: Fri, 17 Oct 2014 11:40:35 +0100 Subject: [PATCH] Hash the same content covered by the signature when referencing previous PDUs rather than reusing the PDU content hashes --- synapse/crypto/event_signing.py | 19 +++++++++--- synapse/federation/pdu_codec.py | 6 ++-- synapse/storage/__init__.py | 9 +++++- synapse/storage/pdu.py | 4 +-- synapse/storage/schema/signatures.sql | 18 +++++++++-- synapse/storage/signatures.py | 44 ++++++++++++++++++++++++--- 6 files changed, 84 insertions(+), 16 deletions(-) diff --git a/synapse/crypto/event_signing.py b/synapse/crypto/event_signing.py index a115967c0..32d60bd30 100644 --- a/synapse/crypto/event_signing.py +++ b/synapse/crypto/event_signing.py @@ -24,15 +24,15 @@ from syutil.crypto.jsonsign import sign_json, verify_signed_json import hashlib -def hash_event_pdu(pdu, hash_algortithm=hashlib.sha256): - hashed = _compute_hash(pdu, hash_algortithm) +def add_event_pdu_content_hash(pdu, hash_algorithm=hashlib.sha256): + hashed = _compute_content_hash(pdu, hash_algorithm) pdu.hashes[hashed.name] = encode_base64(hashed.digest()) return pdu -def check_event_pdu_hash(pdu, hash_algorithm=hashlib.sha256): +def check_event_pdu_content_hash(pdu, hash_algorithm=hashlib.sha256): """Check whether the hash for this PDU matches the contents""" - computed_hash = _compute_hash(pdu, hash_algortithm) + computed_hash = _compute_content_hash(pdu, hash_algortithm) if computed_hash.name not in pdu.hashes: raise Exception("Algorithm %s not in hashes %s" % ( computed_hash.name, list(pdu.hashes) @@ -45,7 +45,7 @@ def check_event_pdu_hash(pdu, hash_algorithm=hashlib.sha256): return message_hash_bytes == computed_hash.digest() -def _compute_hash(pdu, hash_algorithm): +def _compute_content_hash(pdu, hash_algorithm): pdu_json = pdu.get_dict() pdu_json.pop("meta", None) pdu_json.pop("signatures", None) @@ -54,6 +54,15 @@ def _compute_hash(pdu, hash_algorithm): return hash_algorithm(pdu_json_bytes) +def compute_pdu_event_reference_hash(pdu, hash_algorithm=hashlib.sha256): + tmp_pdu = Pdu(**pdu.get_dict()) + tmp_pdu = prune_pdu(tmp_pdu) + pdu_json = tmp_pdu.get_dict() + pdu_json_bytes = encode_canonical_json(pdu_json) + hashed = hash_algorithm(pdu_json_bytes) + return (hashed.name, hashed.digest()) + + def sign_event_pdu(pdu, signature_name, signing_key): tmp_pdu = Pdu(**pdu.get_dict()) tmp_pdu = prune_pdu(tmp_pdu) diff --git a/synapse/federation/pdu_codec.py b/synapse/federation/pdu_codec.py index 11fd7264b..7e574f451 100644 --- a/synapse/federation/pdu_codec.py +++ b/synapse/federation/pdu_codec.py @@ -14,7 +14,9 @@ # limitations under the License. from .units import Pdu -from synapse.crypto.event_signing import hash_event_pdu, sign_event_pdu +from synapse.crypto.event_signing import ( + add_event_pdu_content_hash, sign_event_pdu +) import copy @@ -97,5 +99,5 @@ class PduCodec(object): kwargs["ts"] = int(self.clock.time_msec()) pdu = Pdu(**kwargs) - pdu = hash_event_pdu(pdu) + pdu = add_event_pdu_content_hash(pdu) return sign_event_pdu(pdu, self.server_name, self.signing_key) diff --git a/synapse/storage/__init__.py b/synapse/storage/__init__.py index af05b4793..1738260cc 100644 --- a/synapse/storage/__init__.py +++ b/synapse/storage/__init__.py @@ -44,6 +44,8 @@ from .signatures import SignatureStore from syutil.base64util import decode_base64 +from synapse.crypto.event_signing import compute_pdu_event_reference_hash + import json import logging import os @@ -165,7 +167,7 @@ class DataStore(RoomMemberStore, RoomStore, for hash_alg, hash_base64 in pdu.hashes.items(): hash_bytes = decode_base64(hash_base64) - self._store_pdu_hash_txn( + self._store_pdu_content_hash_txn( txn, pdu.pdu_id, pdu.origin, hash_alg, hash_bytes, ) @@ -185,6 +187,11 @@ class DataStore(RoomMemberStore, RoomStore, hash_bytes ) + (ref_alg, ref_hash_bytes) = compute_pdu_event_reference_hash(pdu) + self._store_pdu_reference_hash_txn( + txn, pdu.pdu_id, pdu.origin, ref_alg, ref_hash_bytes + ) + if pdu.is_state: self._persist_state_txn(txn, pdu.prev_pdus, cols) else: diff --git a/synapse/storage/pdu.py b/synapse/storage/pdu.py index a423b42db..3a90c382f 100644 --- a/synapse/storage/pdu.py +++ b/synapse/storage/pdu.py @@ -69,7 +69,7 @@ class PduStore(SQLBaseStore): edge_hashes = self._get_prev_pdu_hashes_txn(txn, pdu_id, origin) - hashes = self._get_pdu_hashes_txn(txn, pdu_id, origin) + hashes = self._get_pdu_content_hashes_txn(txn, pdu_id, origin) signatures = self._get_pdu_origin_signatures_txn( txn, pdu_id, origin ) @@ -317,7 +317,7 @@ class PduStore(SQLBaseStore): results = [] for pdu_id, origin, depth in txn.fetchall(): - hashes = self._get_pdu_hashes_txn(txn, pdu_id, origin) + hashes = self._get_pdu_reference_hashes_txn(txn, pdu_id, origin) sha256_bytes = hashes["sha256"] prev_hashes = {"sha256": encode_base64(sha256_bytes)} results.append((pdu_id, origin, prev_hashes, depth)) diff --git a/synapse/storage/schema/signatures.sql b/synapse/storage/schema/signatures.sql index a72c4dc35..1c45a51be 100644 --- a/synapse/storage/schema/signatures.sql +++ b/synapse/storage/schema/signatures.sql @@ -13,7 +13,7 @@ * limitations under the License. */ -CREATE TABLE IF NOT EXISTS pdu_hashes ( +CREATE TABLE IF NOT EXISTS pdu_content_hashes ( pdu_id TEXT, origin TEXT, algorithm TEXT, @@ -21,7 +21,21 @@ CREATE TABLE IF NOT EXISTS pdu_hashes ( CONSTRAINT uniqueness UNIQUE (pdu_id, origin, algorithm) ); -CREATE INDEX IF NOT EXISTS pdu_hashes_id ON pdu_hashes (pdu_id, origin); +CREATE INDEX IF NOT EXISTS pdu_content_hashes_id ON pdu_content_hashes ( + pdu_id, origin +); + +CREATE TABLE IF NOT EXISTS pdu_reference_hashes ( + pdu_id TEXT, + origin TEXT, + algorithm TEXT, + hash BLOB, + CONSTRAINT uniqueness UNIQUE (pdu_id, origin, algorithm) +); + +CREATE INDEX IF NOT EXISTS pdu_reference_hashes_id ON pdu_reference_hashes ( + pdu_id, origin +); CREATE TABLE IF NOT EXISTS pdu_origin_signatures ( pdu_id TEXT, diff --git a/synapse/storage/signatures.py b/synapse/storage/signatures.py index 114710248..85eec7ffb 100644 --- a/synapse/storage/signatures.py +++ b/synapse/storage/signatures.py @@ -21,7 +21,7 @@ from twisted.internet import defer class SignatureStore(SQLBaseStore): """Persistence for PDU signatures and hashes""" - def _get_pdu_hashes_txn(self, txn, pdu_id, origin): + def _get_pdu_content_hashes_txn(self, txn, pdu_id, origin): """Get all the hashes for a given PDU. Args: txn (cursor): @@ -32,13 +32,14 @@ class SignatureStore(SQLBaseStore): """ query = ( "SELECT algorithm, hash" - " FROM pdu_hashes" + " FROM pdu_content_hashes" " WHERE pdu_id = ? and origin = ?" ) txn.execute(query, (pdu_id, origin)) return dict(txn.fetchall()) - def _store_pdu_hash_txn(self, txn, pdu_id, origin, algorithm, hash_bytes): + def _store_pdu_content_hash_txn(self, txn, pdu_id, origin, algorithm, + hash_bytes): """Store a hash for a PDU Args: txn (cursor): @@ -47,13 +48,48 @@ class SignatureStore(SQLBaseStore): algorithm (str): Hashing algorithm. hash_bytes (bytes): Hash function output bytes. """ - self._simple_insert_txn(txn, "pdu_hashes", { + self._simple_insert_txn(txn, "pdu_content_hashes", { "pdu_id": pdu_id, "origin": origin, "algorithm": algorithm, "hash": buffer(hash_bytes), }) + def _get_pdu_reference_hashes_txn(self, txn, pdu_id, origin): + """Get all the hashes for a given PDU. + Args: + txn (cursor): + pdu_id (str): Id for the PDU. + origin (str): origin of the PDU. + Returns: + A dict of algorithm -> hash. + """ + query = ( + "SELECT algorithm, hash" + " FROM pdu_reference_hashes" + " WHERE pdu_id = ? and origin = ?" + ) + txn.execute(query, (pdu_id, origin)) + return dict(txn.fetchall()) + + def _store_pdu_reference_hash_txn(self, txn, pdu_id, origin, algorithm, + hash_bytes): + """Store a hash for a PDU + Args: + txn (cursor): + pdu_id (str): Id for the PDU. + origin (str): origin of the PDU. + algorithm (str): Hashing algorithm. + hash_bytes (bytes): Hash function output bytes. + """ + self._simple_insert_txn(txn, "pdu_reference_hashes", { + "pdu_id": pdu_id, + "origin": origin, + "algorithm": algorithm, + "hash": buffer(hash_bytes), + }) + + def _get_pdu_origin_signatures_txn(self, txn, pdu_id, origin): """Get all the signatures for a given PDU. Args: