forked-synapse/synapse/rest/client/keys.py
Richard van der Hoff 3aae60f17b
Enable cross-signing key upload without UIA (#17284)
Per MSC3967, which is now stable, we should not require UIA when
uploading cross-signing keys for the first time.

Fixes: #17227
2024-06-14 11:14:56 +01:00

482 lines
16 KiB
Python

#
# This file is licensed under the Affero General Public License (AGPL) version 3.
#
# Copyright 2020 The Matrix.org Foundation C.I.C.
# Copyright 2015, 2016 OpenMarket Ltd
# Copyright (C) 2023 New Vector, Ltd
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# See the GNU Affero General Public License for more details:
# <https://www.gnu.org/licenses/agpl-3.0.html>.
#
# Originally licensed under the Apache License, Version 2.0:
# <http://www.apache.org/licenses/LICENSE-2.0>.
#
# [This file includes modifications made by New Vector Limited]
#
#
import logging
import re
from collections import Counter
from http import HTTPStatus
from typing import TYPE_CHECKING, Any, Dict, Optional, Tuple
from synapse.api.errors import Codes, InvalidAPICallError, SynapseError
from synapse.http.server import HttpServer
from synapse.http.servlet import (
RestServlet,
parse_integer,
parse_json_object_from_request,
parse_string,
)
from synapse.http.site import SynapseRequest
from synapse.logging.opentracing import log_kv, set_tag
from synapse.rest.client._base import client_patterns, interactive_auth_handler
from synapse.types import JsonDict, StreamToken
from synapse.util.cancellation import cancellable
if TYPE_CHECKING:
from synapse.server import HomeServer
logger = logging.getLogger(__name__)
class KeyUploadServlet(RestServlet):
"""
POST /keys/upload HTTP/1.1
Content-Type: application/json
{
"device_keys": {
"user_id": "<user_id>",
"device_id": "<device_id>",
"valid_until_ts": <millisecond_timestamp>,
"algorithms": [
"m.olm.curve25519-aes-sha2",
]
"keys": {
"<algorithm>:<device_id>": "<key_base64>",
},
"signatures:" {
"<user_id>" {
"<algorithm>:<device_id>": "<signature_base64>"
}
}
},
"fallback_keys": {
"<algorithm>:<device_id>": "<key_base64>",
"signed_<algorithm>:<device_id>": {
"fallback": true,
"key": "<key_base64>",
"signatures": {
"<user_id>": {
"<algorithm>:<device_id>": "<key_base64>"
}
}
}
}
"one_time_keys": {
"<algorithm>:<key_id>": "<key_base64>"
},
}
response, e.g.:
{
"one_time_key_counts": {
"curve25519": 10,
"signed_curve25519": 20
}
}
"""
PATTERNS = client_patterns("/keys/upload(/(?P<device_id>[^/]+))?$")
CATEGORY = "Encryption requests"
def __init__(self, hs: "HomeServer"):
super().__init__()
self.auth = hs.get_auth()
self.e2e_keys_handler = hs.get_e2e_keys_handler()
self.device_handler = hs.get_device_handler()
self._clock = hs.get_clock()
self._store = hs.get_datastores().main
async def on_POST(
self, request: SynapseRequest, device_id: Optional[str]
) -> Tuple[int, JsonDict]:
requester = await self.auth.get_user_by_req(request, allow_guest=True)
user_id = requester.user.to_string()
body = parse_json_object_from_request(request)
if device_id is not None:
# Providing the device_id should only be done for setting keys
# for dehydrated devices; however, we allow it for any device for
# compatibility with older clients.
if requester.device_id is not None and device_id != requester.device_id:
dehydrated_device = await self.device_handler.get_dehydrated_device(
user_id
)
if dehydrated_device is not None and device_id != dehydrated_device[0]:
set_tag("error", True)
log_kv(
{
"message": "Client uploading keys for a different device",
"logged_in_id": requester.device_id,
"key_being_uploaded": device_id,
}
)
logger.warning(
"Client uploading keys for a different device "
"(logged in as %s, uploading for %s)",
requester.device_id,
device_id,
)
else:
device_id = requester.device_id
if device_id is None:
raise SynapseError(
400, "To upload keys, you must pass device_id when authenticating"
)
result = await self.e2e_keys_handler.upload_keys_for_user(
user_id=user_id, device_id=device_id, keys=body
)
return 200, result
class KeyQueryServlet(RestServlet):
"""
POST /keys/query HTTP/1.1
Content-Type: application/json
{
"device_keys": {
"<user_id>": ["<device_id>"]
} }
HTTP/1.1 200 OK
{
"device_keys": {
"<user_id>": {
"<device_id>": {
"user_id": "<user_id>", // Duplicated to be signed
"device_id": "<device_id>", // Duplicated to be signed
"valid_until_ts": <millisecond_timestamp>,
"algorithms": [ // List of supported algorithms
"m.olm.curve25519-aes-sha2",
],
"keys": { // Must include a ed25519 signing key
"<algorithm>:<key_id>": "<key_base64>",
},
"signatures:" {
// Must be signed with device's ed25519 key
"<user_id>/<device_id>": {
"<algorithm>:<key_id>": "<signature_base64>"
}
// Must be signed by this server.
"<server_name>": {
"<algorithm>:<key_id>": "<signature_base64>"
} } } } } }
"""
PATTERNS = client_patterns("/keys/query$")
CATEGORY = "Encryption requests"
def __init__(self, hs: "HomeServer"):
super().__init__()
self.auth = hs.get_auth()
self.e2e_keys_handler = hs.get_e2e_keys_handler()
@cancellable
async def on_POST(self, request: SynapseRequest) -> Tuple[int, JsonDict]:
requester = await self.auth.get_user_by_req(request, allow_guest=True)
user_id = requester.user.to_string()
device_id = requester.device_id
timeout = parse_integer(request, "timeout", 10 * 1000)
body = parse_json_object_from_request(request)
device_keys = body.get("device_keys")
if not isinstance(device_keys, dict):
raise InvalidAPICallError("'device_keys' must be a JSON object")
def is_list_of_strings(values: Any) -> bool:
return isinstance(values, list) and all(isinstance(v, str) for v in values)
if any(not is_list_of_strings(keys) for keys in device_keys.values()):
raise InvalidAPICallError(
"'device_keys' values must be a list of strings",
)
result = await self.e2e_keys_handler.query_devices(
body, timeout, user_id, device_id
)
return 200, result
class KeyChangesServlet(RestServlet):
"""Returns the list of changes of keys between two stream tokens (may return
spurious extra results, since we currently ignore the `to` param).
GET /keys/changes?from=...&to=...
200 OK
{ "changed": ["@foo:example.com"] }
"""
PATTERNS = client_patterns("/keys/changes$")
CATEGORY = "Encryption requests"
def __init__(self, hs: "HomeServer"):
super().__init__()
self.auth = hs.get_auth()
self.device_handler = hs.get_device_handler()
self.store = hs.get_datastores().main
@cancellable
async def on_GET(self, request: SynapseRequest) -> Tuple[int, JsonDict]:
requester = await self.auth.get_user_by_req(request, allow_guest=True)
from_token_string = parse_string(request, "from", required=True)
set_tag("from", from_token_string)
# We want to enforce they do pass us one, but we ignore it and return
# changes after the "to" as well as before.
#
# XXX This does not enforce that "to" is passed.
set_tag("to", str(parse_string(request, "to")))
from_token = await StreamToken.from_string(self.store, from_token_string)
user_id = requester.user.to_string()
results = await self.device_handler.get_user_ids_changed(user_id, from_token)
return 200, results
class OneTimeKeyServlet(RestServlet):
"""
POST /keys/claim HTTP/1.1
{
"one_time_keys": {
"<user_id>": {
"<device_id>": "<algorithm>"
} } }
HTTP/1.1 200 OK
{
"one_time_keys": {
"<user_id>": {
"<device_id>": {
"<algorithm>:<key_id>": "<key_base64>"
} } } }
"""
PATTERNS = client_patterns("/keys/claim$")
CATEGORY = "Encryption requests"
def __init__(self, hs: "HomeServer"):
super().__init__()
self.auth = hs.get_auth()
self.e2e_keys_handler = hs.get_e2e_keys_handler()
async def on_POST(self, request: SynapseRequest) -> Tuple[int, JsonDict]:
requester = await self.auth.get_user_by_req(request, allow_guest=True)
timeout = parse_integer(request, "timeout", 10 * 1000)
body = parse_json_object_from_request(request)
# Generate a count for each algorithm, which is hard-coded to 1.
query: Dict[str, Dict[str, Dict[str, int]]] = {}
for user_id, one_time_keys in body.get("one_time_keys", {}).items():
for device_id, algorithm in one_time_keys.items():
query.setdefault(user_id, {})[device_id] = {algorithm: 1}
result = await self.e2e_keys_handler.claim_one_time_keys(
query, requester.user, timeout, always_include_fallback_keys=False
)
return 200, result
class UnstableOneTimeKeyServlet(RestServlet):
"""
Identical to the stable endpoint (OneTimeKeyServlet) except it allows for
querying for multiple OTKs at once and always includes fallback keys in the
response.
POST /keys/claim HTTP/1.1
{
"one_time_keys": {
"<user_id>": {
"<device_id>": ["<algorithm>", ...]
} } }
HTTP/1.1 200 OK
{
"one_time_keys": {
"<user_id>": {
"<device_id>": {
"<algorithm>:<key_id>": "<key_base64>"
} } } }
"""
PATTERNS = [re.compile(r"^/_matrix/client/unstable/org.matrix.msc3983/keys/claim$")]
CATEGORY = "Encryption requests"
def __init__(self, hs: "HomeServer"):
super().__init__()
self.auth = hs.get_auth()
self.e2e_keys_handler = hs.get_e2e_keys_handler()
async def on_POST(self, request: SynapseRequest) -> Tuple[int, JsonDict]:
requester = await self.auth.get_user_by_req(request, allow_guest=True)
timeout = parse_integer(request, "timeout", 10 * 1000)
body = parse_json_object_from_request(request)
# Generate a count for each algorithm.
query: Dict[str, Dict[str, Dict[str, int]]] = {}
for user_id, one_time_keys in body.get("one_time_keys", {}).items():
for device_id, algorithms in one_time_keys.items():
query.setdefault(user_id, {})[device_id] = Counter(algorithms)
result = await self.e2e_keys_handler.claim_one_time_keys(
query, requester.user, timeout, always_include_fallback_keys=True
)
return 200, result
class SigningKeyUploadServlet(RestServlet):
"""
POST /keys/device_signing/upload HTTP/1.1
Content-Type: application/json
{
}
"""
PATTERNS = client_patterns("/keys/device_signing/upload$", releases=("v3",))
def __init__(self, hs: "HomeServer"):
super().__init__()
self.hs = hs
self.auth = hs.get_auth()
self.e2e_keys_handler = hs.get_e2e_keys_handler()
self.auth_handler = hs.get_auth_handler()
@interactive_auth_handler
async def on_POST(self, request: SynapseRequest) -> Tuple[int, JsonDict]:
requester = await self.auth.get_user_by_req(request)
user_id = requester.user.to_string()
body = parse_json_object_from_request(request)
(
is_cross_signing_setup,
master_key_updatable_without_uia,
) = await self.e2e_keys_handler.check_cross_signing_setup(user_id)
# Resending exactly the same keys should just 200 OK without doing a UIA prompt.
keys_are_different = await self.e2e_keys_handler.has_different_keys(
user_id, body
)
if not keys_are_different:
return 200, {}
# The keys are different; is x-signing set up? If no, then this is first-time
# setup, and that is allowed without UIA, per MSC3967.
# If yes, then we need to authenticate the change.
if is_cross_signing_setup:
# With MSC3861, UIA is not possible. Instead, the auth service has to
# explicitly mark the master key as replaceable.
if self.hs.config.experimental.msc3861.enabled:
if not master_key_updatable_without_uia:
config = self.hs.config.experimental.msc3861
if config.account_management_url is not None:
url = f"{config.account_management_url}?action=org.matrix.cross_signing_reset"
else:
url = config.issuer
raise SynapseError(
HTTPStatus.NOT_IMPLEMENTED,
"To reset your end-to-end encryption cross-signing identity, "
f"you first need to approve it at {url} and then try again.",
Codes.UNRECOGNIZED,
)
else:
# Without MSC3861, we require UIA.
await self.auth_handler.validate_user_via_ui_auth(
requester,
request,
body,
"reset the device signing key on your account",
# Do not allow skipping of UIA auth.
can_skip_ui_auth=False,
)
result = await self.e2e_keys_handler.upload_signing_keys_for_user(user_id, body)
return 200, result
class SignaturesUploadServlet(RestServlet):
"""
POST /keys/signatures/upload HTTP/1.1
Content-Type: application/json
{
"@alice:example.com": {
"<device_id>": {
"user_id": "<user_id>",
"device_id": "<device_id>",
"algorithms": [
"m.olm.curve25519-aes-sha2",
"m.megolm.v1.aes-sha2"
],
"keys": {
"<algorithm>:<device_id>": "<key_base64>",
},
"signatures": {
"<signing_user_id>": {
"<algorithm>:<signing_key_base64>": "<signature_base64>>"
}
}
}
}
}
"""
PATTERNS = client_patterns("/keys/signatures/upload$")
def __init__(self, hs: "HomeServer"):
super().__init__()
self.auth = hs.get_auth()
self.e2e_keys_handler = hs.get_e2e_keys_handler()
async def on_POST(self, request: SynapseRequest) -> Tuple[int, JsonDict]:
requester = await self.auth.get_user_by_req(request, allow_guest=True)
user_id = requester.user.to_string()
body = parse_json_object_from_request(request)
result = await self.e2e_keys_handler.upload_signatures_for_device_keys(
user_id, body
)
return 200, result
def register_servlets(hs: "HomeServer", http_server: HttpServer) -> None:
KeyUploadServlet(hs).register(http_server)
KeyQueryServlet(hs).register(http_server)
KeyChangesServlet(hs).register(http_server)
OneTimeKeyServlet(hs).register(http_server)
if hs.config.experimental.msc3983_appservice_otk_claims:
UnstableOneTimeKeyServlet(hs).register(http_server)
if hs.config.worker.worker_app is None:
SigningKeyUploadServlet(hs).register(http_server)
SignaturesUploadServlet(hs).register(http_server)