diff options
Diffstat (limited to 'synapse')
| -rw-r--r-- | synapse/crypto/event_signing.py | 37 | ||||
| -rw-r--r-- | synapse/events/builder.py | 10 |
2 files changed, 28 insertions, 19 deletions
diff --git a/synapse/crypto/event_signing.py b/synapse/crypto/event_signing.py index 78032cd6eb..5aae33567d 100644 --- a/synapse/crypto/event_signing.py +++ b/synapse/crypto/event_signing.py @@ -41,9 +41,10 @@ def _check_dict_hash( hash_log: str, hashes: Any, d: JsonDict, - hash_algorithm: Hasher = hashlib.sha256, + hash_algorithm: Hasher, + lpdu_hash: bool, ) -> bool: - name, expected_hash = compute_content_hash(d, hash_algorithm) + name, expected_hash = compute_content_hash(d, hash_algorithm, lpdu_hash) logger.debug( "Verifying %s hash on %s (expecting: %s)", hash_log, @@ -90,7 +91,12 @@ def check_event_content_hash( hashes = event.get("hashes") if not _check_dict_hash( - event.event_id, "content", hashes, event.get_pdu_json(), hash_algorithm + event.event_id, + "content", + hashes, + event.get_pdu_json(), + hash_algorithm, + lpdu_hash=False, ): return False @@ -104,6 +110,7 @@ def check_event_content_hash( lpdu_hashes, event.get_linearized_pdu_json(), hash_algorithm, + lpdu_hash=True, ) # Non-linearized matrix doesn't care about other checks. @@ -111,7 +118,7 @@ def check_event_content_hash( def compute_content_hash( - event_dict: Dict[str, Any], hash_algorithm: Hasher + event_dict: Dict[str, Any], hash_algorithm: Hasher, lpdu_hash: False ) -> Tuple[str, bytes]: """Compute the content hash of an event, which is the hash of the unredacted event. @@ -120,6 +127,7 @@ def compute_content_hash( event_dict: The unredacted event as a dict hash_algorithm: A hasher from `hashlib`, e.g. hashlib.sha256, to use to hash the event + lpdu_hash: True if the LPDU hash is being calculated. Returns: A tuple of the name of hash and the hash as raw bytes. @@ -131,15 +139,13 @@ def compute_content_hash( hashes = event_dict.pop("hashes", {}) - # If we are calculating the content hash of an LPDU, `hashes` - # should be removed entirely. - if "hub_server" not in event_dict: - # Otherwise, we are calculating the content hash of a PDU. In that - # case, we keep the "lpdu" field inside "hashes", if it exists. - sha256_lpdu_hash = hashes.get("lpdu", {}).get("sha256") - if sha256_lpdu_hash is not None: - lpdu_dict = event_dict.setdefault("hashes", {}).setdefault("lpdu", {}) - lpdu_dict["sha256"] = sha256_lpdu_hash + # If we are calculating the content hash of a PDU sent on behalf of another + # server, hashes only`contains the lpdu hash. + # + # TODO(LM) This is wrong in that an incorrectly formatted event could have + # bad content hashes from this. + if not lpdu_hash and "lpdu" in hashes: + event_dict["hashes"] = {"lpdu": hashes["lpdu"]} event_dict.pop("outlier", None) event_dict.pop("destinations", None) @@ -225,7 +231,10 @@ def add_hashes_and_signatures( signing_key: The key to sign with """ - name, digest = compute_content_hash(event_dict, hash_algorithm=hashlib.sha256) + # Synapse only ever generates PDUs, not LPDUs. + name, digest = compute_content_hash( + event_dict, hash_algorithm=hashlib.sha256, lpdu_hash=False + ) event_dict.setdefault("hashes", {})[name] = encode_base64(digest) diff --git a/synapse/events/builder.py b/synapse/events/builder.py index df628c9a61..9efaff77c9 100644 --- a/synapse/events/builder.py +++ b/synapse/events/builder.py @@ -189,6 +189,11 @@ class EventBuilder: if self._origin_server_ts is not None: event_dict["origin_server_ts"] = self._origin_server_ts + if self.room_version.linearized_matrix and self._lpdu_hashes: + event_dict.setdefault("hashes", {})["lpdu"] = self._lpdu_hashes + if self.room_version.linearized_matrix and self._lpdu_signatures: + event_dict.setdefault("signatures", {}).update(self._lpdu_signatures) + event = create_local_event_from_event_dict( clock=self._clock, hostname=self._hostname, @@ -198,11 +203,6 @@ class EventBuilder: internal_metadata_dict=self.internal_metadata.get_dict(), ) - if self.room_version.linearized_matrix and self._lpdu_hashes: - event.hashes["lpdu"] = self._lpdu_hashes - if self.room_version.linearized_matrix and self._lpdu_signatures: - event.signatures.update(self._lpdu_signatures) - return event |