diff --git a/synapse/crypto/event_signing.py b/synapse/crypto/event_signing.py
index 8774b28967..1dfa727fcf 100644
--- a/synapse/crypto/event_signing.py
+++ b/synapse/crypto/event_signing.py
@@ -23,14 +23,14 @@ from signedjson.sign import sign_json
from unpaddedbase64 import decode_base64, encode_base64
from synapse.api.errors import Codes, SynapseError
-from synapse.events.utils import prune_event
+from synapse.events.utils import prune_event, prune_event_dict
logger = logging.getLogger(__name__)
def check_event_content_hash(event, hash_algorithm=hashlib.sha256):
"""Check whether the hash for this PDU matches the contents"""
- name, expected_hash = compute_content_hash(event, hash_algorithm)
+ name, expected_hash = compute_content_hash(event.get_pdu_json(), hash_algorithm)
logger.debug("Expecting hash: %s", encode_base64(expected_hash))
# some malformed events lack a 'hashes'. Protect against it being missing
@@ -59,35 +59,70 @@ def check_event_content_hash(event, hash_algorithm=hashlib.sha256):
return message_hash_bytes == expected_hash
-def compute_content_hash(event, hash_algorithm):
- event_json = event.get_pdu_json()
- event_json.pop("age_ts", None)
- event_json.pop("unsigned", None)
- event_json.pop("signatures", None)
- event_json.pop("hashes", None)
- event_json.pop("outlier", None)
- event_json.pop("destinations", None)
+def compute_content_hash(event_dict, hash_algorithm):
+ """Compute the content hash of an event, which is the hash of the
+ unredacted event.
- event_json_bytes = encode_canonical_json(event_json)
+ Args:
+ event_dict (dict): The unredacted event as a dict
+ hash_algorithm: A hasher from `hashlib`, e.g. hashlib.sha256, to use
+ to hash the event
+
+ Returns:
+ tuple[str, bytes]: A tuple of the name of hash and the hash as raw
+ bytes.
+ """
+ event_dict = dict(event_dict)
+ event_dict.pop("age_ts", None)
+ event_dict.pop("unsigned", None)
+ event_dict.pop("signatures", None)
+ event_dict.pop("hashes", None)
+ event_dict.pop("outlier", None)
+ event_dict.pop("destinations", None)
+
+ event_json_bytes = encode_canonical_json(event_dict)
hashed = hash_algorithm(event_json_bytes)
return (hashed.name, hashed.digest())
def compute_event_reference_hash(event, hash_algorithm=hashlib.sha256):
+ """Computes the event reference hash. This is the hash of the redacted
+ event.
+
+ Args:
+ event (FrozenEvent)
+ hash_algorithm: A hasher from `hashlib`, e.g. hashlib.sha256, to use
+ to hash the event
+
+ Returns:
+ tuple[str, bytes]: A tuple of the name of hash and the hash as raw
+ bytes.
+ """
tmp_event = prune_event(event)
- event_json = tmp_event.get_pdu_json()
- event_json.pop("signatures", None)
- event_json.pop("age_ts", None)
- event_json.pop("unsigned", None)
- event_json_bytes = encode_canonical_json(event_json)
+ event_dict = tmp_event.get_pdu_json()
+ event_dict.pop("signatures", None)
+ event_dict.pop("age_ts", None)
+ event_dict.pop("unsigned", None)
+ event_json_bytes = encode_canonical_json(event_dict)
hashed = hash_algorithm(event_json_bytes)
return (hashed.name, hashed.digest())
-def compute_event_signature(event, signature_name, signing_key):
- tmp_event = prune_event(event)
- redact_json = tmp_event.get_pdu_json()
+def compute_event_signature(event_dict, signature_name, signing_key):
+ """Compute the signature of the event for the given name and key.
+
+ Args:
+ event_dict (dict): The event as a dict
+ signature_name (str): The name of the entity signing the event
+ (typically the server's hostname).
+ signing_key (syutil.crypto.SigningKey): The key to sign with
+
+ Returns:
+ dict[str, dict[str, str]]: Returns a dictionary in the same format of
+ an event's signatures field.
+ """
+ redact_json = prune_event_dict(event_dict)
redact_json.pop("age_ts", None)
redact_json.pop("unsigned", None)
logger.debug("Signing event: %s", encode_canonical_json(redact_json))
@@ -96,25 +131,25 @@ def compute_event_signature(event, signature_name, signing_key):
return redact_json["signatures"]
-def add_hashes_and_signatures(event, signature_name, signing_key,
+def add_hashes_and_signatures(event_dict, signature_name, signing_key,
hash_algorithm=hashlib.sha256):
- # if hasattr(event, "old_state_events"):
- # state_json_bytes = encode_canonical_json(
- # [e.event_id for e in event.old_state_events.values()]
- # )
- # hashed = hash_algorithm(state_json_bytes)
- # event.state_hash = {
- # hashed.name: encode_base64(hashed.digest())
- # }
-
- name, digest = compute_content_hash(event, hash_algorithm=hash_algorithm)
-
- if not hasattr(event, "hashes"):
- event.hashes = {}
- event.hashes[name] = encode_base64(digest)
-
- event.signatures = compute_event_signature(
- event,
+ """Add content hash and sign the event
+
+ Args:
+ event_dict (dict): The event to add hashes to and sign
+ signature_name (str): The name of the entity signing the event
+ (typically the server's hostname).
+ signing_key (syutil.crypto.SigningKey): The key to sign with
+ hash_algorithm: A hasher from `hashlib`, e.g. hashlib.sha256, to use
+ to hash the event
+ """
+
+ name, digest = compute_content_hash(event_dict, hash_algorithm=hash_algorithm)
+
+ event_dict.setdefault("hashes", {})[name] = encode_base64(digest)
+
+ event_dict["signatures"] = compute_event_signature(
+ event_dict,
signature_name=signature_name,
signing_key=signing_key,
)
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