402 lines
14 KiB
Python
402 lines
14 KiB
Python
# Copyright 2017, 2018 New Vector Ltd
|
|
#
|
|
# Licensed under the Apache License, Version 2.0 (the "License");
|
|
# you may not use this file except in compliance with the License.
|
|
# You may obtain a copy of the License at
|
|
#
|
|
# http://www.apache.org/licenses/LICENSE-2.0
|
|
#
|
|
# Unless required by applicable law or agreed to in writing, software
|
|
# distributed under the License is distributed on an "AS IS" BASIS,
|
|
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
# See the License for the specific language governing permissions and
|
|
# limitations under the License.
|
|
|
|
import logging
|
|
from typing import TYPE_CHECKING, Optional, Tuple, cast
|
|
|
|
from synapse.api.errors import Codes, NotFoundError, SynapseError
|
|
from synapse.http.server import HttpServer
|
|
from synapse.http.servlet import (
|
|
RestServlet,
|
|
parse_json_object_from_request,
|
|
parse_string,
|
|
)
|
|
from synapse.http.site import SynapseRequest
|
|
from synapse.types import JsonDict
|
|
|
|
from ._base import client_patterns
|
|
|
|
if TYPE_CHECKING:
|
|
from synapse.server import HomeServer
|
|
|
|
logger = logging.getLogger(__name__)
|
|
|
|
|
|
class RoomKeysServlet(RestServlet):
|
|
PATTERNS = client_patterns(
|
|
"/room_keys/keys(/(?P<room_id>[^/]+))?(/(?P<session_id>[^/]+))?$"
|
|
)
|
|
|
|
def __init__(self, hs: "HomeServer"):
|
|
super().__init__()
|
|
self.auth = hs.get_auth()
|
|
self.e2e_room_keys_handler = hs.get_e2e_room_keys_handler()
|
|
|
|
async def on_PUT(
|
|
self, request: SynapseRequest, room_id: Optional[str], session_id: Optional[str]
|
|
) -> Tuple[int, JsonDict]:
|
|
"""
|
|
Uploads one or more encrypted E2E room keys for backup purposes.
|
|
room_id: the ID of the room the keys are for (optional)
|
|
session_id: the ID for the E2E room keys for the room (optional)
|
|
version: the version of the user's backup which this data is for.
|
|
the version must already have been created via the /room_keys/version API.
|
|
|
|
Each session has:
|
|
* first_message_index: a numeric index indicating the oldest message
|
|
encrypted by this session.
|
|
* forwarded_count: how many times the uploading client claims this key
|
|
has been shared (forwarded)
|
|
* is_verified: whether the client that uploaded the keys claims they
|
|
were sent by a device which they've verified
|
|
* session_data: base64-encrypted data describing the session.
|
|
|
|
Returns 200 OK on success with body {}
|
|
Returns 403 Forbidden if the version in question is not the most recently
|
|
created version (i.e. if this is an old client trying to write to a stale backup)
|
|
Returns 404 Not Found if the version in question doesn't exist
|
|
|
|
The API is designed to be otherwise agnostic to the room_key encryption
|
|
algorithm being used. Sessions are merged with existing ones in the
|
|
backup using the heuristics:
|
|
* is_verified sessions always win over unverified sessions
|
|
* older first_message_index always win over newer sessions
|
|
* lower forwarded_count always wins over higher forwarded_count
|
|
|
|
We trust the clients not to lie and corrupt their own backups.
|
|
It also means that if your access_token is stolen, the attacker could
|
|
delete your backup.
|
|
|
|
POST /room_keys/keys/!abc:matrix.org/c0ff33?version=1 HTTP/1.1
|
|
Content-Type: application/json
|
|
|
|
{
|
|
"first_message_index": 1,
|
|
"forwarded_count": 1,
|
|
"is_verified": false,
|
|
"session_data": "SSBBTSBBIEZJU0gK"
|
|
}
|
|
|
|
Or...
|
|
|
|
POST /room_keys/keys/!abc:matrix.org?version=1 HTTP/1.1
|
|
Content-Type: application/json
|
|
|
|
{
|
|
"sessions": {
|
|
"c0ff33": {
|
|
"first_message_index": 1,
|
|
"forwarded_count": 1,
|
|
"is_verified": false,
|
|
"session_data": "SSBBTSBBIEZJU0gK"
|
|
}
|
|
}
|
|
}
|
|
|
|
Or...
|
|
|
|
POST /room_keys/keys?version=1 HTTP/1.1
|
|
Content-Type: application/json
|
|
|
|
{
|
|
"rooms": {
|
|
"!abc:matrix.org": {
|
|
"sessions": {
|
|
"c0ff33": {
|
|
"first_message_index": 1,
|
|
"forwarded_count": 1,
|
|
"is_verified": false,
|
|
"session_data": "SSBBTSBBIEZJU0gK"
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
"""
|
|
requester = await self.auth.get_user_by_req(request, allow_guest=False)
|
|
user_id = requester.user.to_string()
|
|
body = parse_json_object_from_request(request)
|
|
version = parse_string(request, "version", required=True)
|
|
|
|
if session_id:
|
|
body = {"sessions": {session_id: body}}
|
|
|
|
if room_id:
|
|
body = {"rooms": {room_id: body}}
|
|
|
|
ret = await self.e2e_room_keys_handler.upload_room_keys(user_id, version, body)
|
|
return 200, ret
|
|
|
|
async def on_GET(
|
|
self, request: SynapseRequest, room_id: Optional[str], session_id: Optional[str]
|
|
) -> Tuple[int, JsonDict]:
|
|
"""
|
|
Retrieves one or more encrypted E2E room keys for backup purposes.
|
|
Symmetric with the PUT version of the API.
|
|
|
|
room_id: the ID of the room to retrieve the keys for (optional)
|
|
session_id: the ID for the E2E room keys to retrieve the keys for (optional)
|
|
version: the version of the user's backup which this data is for.
|
|
the version must already have been created via the /change_secret API.
|
|
|
|
Returns as follows:
|
|
|
|
GET /room_keys/keys/!abc:matrix.org/c0ff33?version=1 HTTP/1.1
|
|
{
|
|
"first_message_index": 1,
|
|
"forwarded_count": 1,
|
|
"is_verified": false,
|
|
"session_data": "SSBBTSBBIEZJU0gK"
|
|
}
|
|
|
|
Or...
|
|
|
|
GET /room_keys/keys/!abc:matrix.org?version=1 HTTP/1.1
|
|
{
|
|
"sessions": {
|
|
"c0ff33": {
|
|
"first_message_index": 1,
|
|
"forwarded_count": 1,
|
|
"is_verified": false,
|
|
"session_data": "SSBBTSBBIEZJU0gK"
|
|
}
|
|
}
|
|
}
|
|
|
|
Or...
|
|
|
|
GET /room_keys/keys?version=1 HTTP/1.1
|
|
{
|
|
"rooms": {
|
|
"!abc:matrix.org": {
|
|
"sessions": {
|
|
"c0ff33": {
|
|
"first_message_index": 1,
|
|
"forwarded_count": 1,
|
|
"is_verified": false,
|
|
"session_data": "SSBBTSBBIEZJU0gK"
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
"""
|
|
requester = await self.auth.get_user_by_req(request, allow_guest=False)
|
|
user_id = requester.user.to_string()
|
|
version = parse_string(request, "version", required=True)
|
|
|
|
room_keys = cast(
|
|
JsonDict,
|
|
await self.e2e_room_keys_handler.get_room_keys(
|
|
user_id, version, room_id, session_id
|
|
),
|
|
)
|
|
|
|
# Convert room_keys to the right format to return.
|
|
if session_id:
|
|
# If the client requests a specific session, but that session was
|
|
# not backed up, then return an M_NOT_FOUND.
|
|
if room_keys["rooms"] == {}:
|
|
raise NotFoundError("No room_keys found")
|
|
else:
|
|
room_keys = room_keys["rooms"][room_id]["sessions"][session_id]
|
|
elif room_id:
|
|
# If the client requests all sessions from a room, but no sessions
|
|
# are found, then return an empty result rather than an error, so
|
|
# that clients don't have to handle an error condition, and an
|
|
# empty result is valid. (Similarly if the client requests all
|
|
# sessions from the backup, but in that case, room_keys is already
|
|
# in the right format, so we don't need to do anything about it.)
|
|
if room_keys["rooms"] == {}:
|
|
room_keys = {"sessions": {}}
|
|
else:
|
|
room_keys = room_keys["rooms"][room_id]
|
|
|
|
return 200, room_keys
|
|
|
|
async def on_DELETE(
|
|
self, request: SynapseRequest, room_id: Optional[str], session_id: Optional[str]
|
|
) -> Tuple[int, JsonDict]:
|
|
"""
|
|
Deletes one or more encrypted E2E room keys for a user for backup purposes.
|
|
|
|
DELETE /room_keys/keys/!abc:matrix.org/c0ff33?version=1
|
|
HTTP/1.1 200 OK
|
|
{}
|
|
|
|
room_id: the ID of the room whose keys to delete (optional)
|
|
session_id: the ID for the E2E session to delete (optional)
|
|
version: the version of the user's backup which this data is for.
|
|
the version must already have been created via the /change_secret API.
|
|
"""
|
|
|
|
requester = await self.auth.get_user_by_req(request, allow_guest=False)
|
|
user_id = requester.user.to_string()
|
|
version = parse_string(request, "version", required=True)
|
|
|
|
ret = await self.e2e_room_keys_handler.delete_room_keys(
|
|
user_id, version, room_id, session_id
|
|
)
|
|
return 200, ret
|
|
|
|
|
|
class RoomKeysNewVersionServlet(RestServlet):
|
|
PATTERNS = client_patterns("/room_keys/version$")
|
|
|
|
def __init__(self, hs: "HomeServer"):
|
|
super().__init__()
|
|
self.auth = hs.get_auth()
|
|
self.e2e_room_keys_handler = hs.get_e2e_room_keys_handler()
|
|
|
|
async def on_POST(self, request: SynapseRequest) -> Tuple[int, JsonDict]:
|
|
"""
|
|
Create a new backup version for this user's room_keys with the given
|
|
info. The version is allocated by the server and returned to the user
|
|
in the response. This API is intended to be used whenever the user
|
|
changes the encryption key for their backups, ensuring that backups
|
|
encrypted with different keys don't collide.
|
|
|
|
It takes out an exclusive lock on this user's room_key backups, to ensure
|
|
clients only upload to the current backup.
|
|
|
|
The algorithm passed in the version info is a reverse-DNS namespaced
|
|
identifier to describe the format of the encrypted backupped keys.
|
|
|
|
The auth_data is { user_id: "user_id", nonce: <random string> }
|
|
encrypted using the algorithm and current encryption key described above.
|
|
|
|
POST /room_keys/version
|
|
Content-Type: application/json
|
|
{
|
|
"algorithm": "m.megolm_backup.v1",
|
|
"auth_data": "dGhpcyBzaG91bGQgYWN0dWFsbHkgYmUgZW5jcnlwdGVkIGpzb24K"
|
|
}
|
|
|
|
HTTP/1.1 200 OK
|
|
Content-Type: application/json
|
|
{
|
|
"version": 12345
|
|
}
|
|
"""
|
|
requester = await self.auth.get_user_by_req(request, allow_guest=False)
|
|
user_id = requester.user.to_string()
|
|
info = parse_json_object_from_request(request)
|
|
|
|
new_version = await self.e2e_room_keys_handler.create_version(user_id, info)
|
|
return 200, {"version": new_version}
|
|
|
|
# we deliberately don't have a PUT /version, as these things really should
|
|
# be immutable to avoid people footgunning
|
|
|
|
|
|
class RoomKeysVersionServlet(RestServlet):
|
|
PATTERNS = client_patterns("/room_keys/version(/(?P<version>[^/]+))?$")
|
|
|
|
def __init__(self, hs: "HomeServer"):
|
|
super().__init__()
|
|
self.auth = hs.get_auth()
|
|
self.e2e_room_keys_handler = hs.get_e2e_room_keys_handler()
|
|
|
|
async def on_GET(
|
|
self, request: SynapseRequest, version: Optional[str]
|
|
) -> Tuple[int, JsonDict]:
|
|
"""
|
|
Retrieve the version information about a given version of the user's
|
|
room_keys backup. If the version part is missing, returns info about the
|
|
most current backup version (if any)
|
|
|
|
It takes out an exclusive lock on this user's room_key backups, to ensure
|
|
clients only upload to the current backup.
|
|
|
|
Returns 404 if the given version does not exist.
|
|
|
|
GET /room_keys/version/12345 HTTP/1.1
|
|
{
|
|
"version": "12345",
|
|
"algorithm": "m.megolm_backup.v1",
|
|
"auth_data": "dGhpcyBzaG91bGQgYWN0dWFsbHkgYmUgZW5jcnlwdGVkIGpzb24K"
|
|
}
|
|
"""
|
|
requester = await self.auth.get_user_by_req(request, allow_guest=False)
|
|
user_id = requester.user.to_string()
|
|
|
|
try:
|
|
info = await self.e2e_room_keys_handler.get_version_info(user_id, version)
|
|
except SynapseError as e:
|
|
if e.code == 404:
|
|
raise SynapseError(404, "No backup found", Codes.NOT_FOUND)
|
|
return 200, info
|
|
|
|
async def on_DELETE(
|
|
self, request: SynapseRequest, version: Optional[str]
|
|
) -> Tuple[int, JsonDict]:
|
|
"""
|
|
Delete the information about a given version of the user's
|
|
room_keys backup. If the version part is missing, deletes the most
|
|
current backup version (if any). Doesn't delete the actual room data.
|
|
|
|
DELETE /room_keys/version/12345 HTTP/1.1
|
|
HTTP/1.1 200 OK
|
|
{}
|
|
"""
|
|
if version is None:
|
|
raise SynapseError(400, "No version specified to delete", Codes.NOT_FOUND)
|
|
|
|
requester = await self.auth.get_user_by_req(request, allow_guest=False)
|
|
user_id = requester.user.to_string()
|
|
|
|
await self.e2e_room_keys_handler.delete_version(user_id, version)
|
|
return 200, {}
|
|
|
|
async def on_PUT(
|
|
self, request: SynapseRequest, version: Optional[str]
|
|
) -> Tuple[int, JsonDict]:
|
|
"""
|
|
Update the information about a given version of the user's room_keys backup.
|
|
|
|
POST /room_keys/version/12345 HTTP/1.1
|
|
Content-Type: application/json
|
|
{
|
|
"algorithm": "m.megolm_backup.v1",
|
|
"auth_data": {
|
|
"public_key": "abcdefg",
|
|
"signatures": {
|
|
"ed25519:something": "hijklmnop"
|
|
}
|
|
},
|
|
"version": "12345"
|
|
}
|
|
|
|
HTTP/1.1 200 OK
|
|
Content-Type: application/json
|
|
{}
|
|
"""
|
|
requester = await self.auth.get_user_by_req(request, allow_guest=False)
|
|
user_id = requester.user.to_string()
|
|
info = parse_json_object_from_request(request)
|
|
|
|
if version is None:
|
|
raise SynapseError(
|
|
400, "No version specified to update", Codes.MISSING_PARAM
|
|
)
|
|
|
|
await self.e2e_room_keys_handler.update_version(user_id, version, info)
|
|
return 200, {}
|
|
|
|
|
|
def register_servlets(hs: "HomeServer", http_server: HttpServer) -> None:
|
|
RoomKeysServlet(hs).register(http_server)
|
|
RoomKeysVersionServlet(hs).register(http_server)
|
|
RoomKeysNewVersionServlet(hs).register(http_server)
|