2014-10-15 16:09:04 +00:00
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# -*- coding: utf-8 -*-
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# Copyright 2014 OpenMarket Ltd
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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2014-10-15 23:09:48 +00:00
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from synapse.federation.units import Pdu
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2014-10-15 16:09:04 +00:00
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from synapse.api.events.utils import prune_pdu
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from syutil.jsonutil import encode_canonical_json
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from syutil.base64util import encode_base64, decode_base64
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from syutil.crypto.jsonsign import sign_json, verify_signed_json
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import hashlib
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2014-10-17 18:41:32 +00:00
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import logging
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logger = logging.getLogger(__name__)
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2014-10-15 16:09:04 +00:00
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2014-10-17 10:40:35 +00:00
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def add_event_pdu_content_hash(pdu, hash_algorithm=hashlib.sha256):
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hashed = _compute_content_hash(pdu, hash_algorithm)
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2014-10-15 23:09:48 +00:00
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pdu.hashes[hashed.name] = encode_base64(hashed.digest())
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2014-10-15 16:09:04 +00:00
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return pdu
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2014-10-17 10:40:35 +00:00
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def check_event_pdu_content_hash(pdu, hash_algorithm=hashlib.sha256):
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2014-10-15 16:09:04 +00:00
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"""Check whether the hash for this PDU matches the contents"""
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2014-10-17 10:40:35 +00:00
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computed_hash = _compute_content_hash(pdu, hash_algortithm)
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2014-10-15 16:09:04 +00:00
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if computed_hash.name not in pdu.hashes:
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raise Exception("Algorithm %s not in hashes %s" % (
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computed_hash.name, list(pdu.hashes)
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))
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message_hash_base64 = hashes[computed_hash.name]
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try:
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message_hash_bytes = decode_base64(message_hash_base64)
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except:
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raise Exception("Invalid base64: %s" % (message_hash_base64,))
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return message_hash_bytes == computed_hash.digest()
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2014-10-17 10:40:35 +00:00
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def _compute_content_hash(pdu, hash_algorithm):
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2014-10-15 16:09:04 +00:00
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pdu_json = pdu.get_dict()
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2014-10-17 15:50:04 +00:00
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#TODO: Make "age_ts" key internal
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2014-10-17 18:41:32 +00:00
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pdu_json.pop("age_ts", None)
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2014-10-17 15:50:04 +00:00
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pdu_json.pop("unsigned", None)
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2014-10-15 16:09:04 +00:00
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pdu_json.pop("signatures", None)
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hashes = pdu_json.pop("hashes", {})
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pdu_json_bytes = encode_canonical_json(pdu_json)
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return hash_algorithm(pdu_json_bytes)
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2014-10-17 10:40:35 +00:00
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def compute_pdu_event_reference_hash(pdu, hash_algorithm=hashlib.sha256):
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tmp_pdu = Pdu(**pdu.get_dict())
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tmp_pdu = prune_pdu(tmp_pdu)
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pdu_json = tmp_pdu.get_dict()
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2014-10-17 18:41:32 +00:00
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pdu_json.pop("signatures", None)
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2014-10-17 10:40:35 +00:00
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pdu_json_bytes = encode_canonical_json(pdu_json)
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hashed = hash_algorithm(pdu_json_bytes)
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return (hashed.name, hashed.digest())
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2014-10-15 16:09:04 +00:00
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def sign_event_pdu(pdu, signature_name, signing_key):
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tmp_pdu = Pdu(**pdu.get_dict())
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tmp_pdu = prune_pdu(tmp_pdu)
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pdu_json = tmp_pdu.get_dict()
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pdu_jdon = sign_json(pdu_json, signature_name, signing_key)
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pdu.signatures = pdu_json["signatures"]
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return pdu
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def verify_signed_event_pdu(pdu, signature_name, verify_key):
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tmp_pdu = Pdu(**pdu.get_dict())
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tmp_pdu = prune_pdu(tmp_pdu)
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pdu_json = tmp_pdu.get_dict()
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verify_signed_json(pdu_json, signature_name, verify_key)
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