1# Copyright 2014-2016 OpenMarket Ltd
2# Copyright 2020-2021 The Matrix.org Foundation C.I.C.
3#
4# Licensed under the Apache License, Version 2.0 (the "License");
5# you may not use this file except in compliance with the License.
6# You may obtain a copy of the License at
7#
8#     http://www.apache.org/licenses/LICENSE-2.0
9#
10# Unless required by applicable law or agreed to in writing, software
11# distributed under the License is distributed on an "AS IS" BASIS,
12# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13# See the License for the specific language governing permissions and
14# limitations under the License.
15import logging
16from typing import TYPE_CHECKING
17
18from synapse.http.server import DirectServeJsonResource, set_cors_headers
19from synapse.http.servlet import parse_boolean
20from synapse.http.site import SynapseRequest
21
22from ._base import parse_media_id, respond_404
23
24if TYPE_CHECKING:
25    from synapse.rest.media.v1.media_repository import MediaRepository
26    from synapse.server import HomeServer
27
28logger = logging.getLogger(__name__)
29
30
31class DownloadResource(DirectServeJsonResource):
32    isLeaf = True
33
34    def __init__(self, hs: "HomeServer", media_repo: "MediaRepository"):
35        super().__init__()
36        self.media_repo = media_repo
37        self.server_name = hs.hostname
38
39    async def _async_render_GET(self, request: SynapseRequest) -> None:
40        set_cors_headers(request)
41        request.setHeader(
42            b"Content-Security-Policy",
43            b"sandbox;"
44            b" default-src 'none';"
45            b" script-src 'none';"
46            b" plugin-types application/pdf;"
47            b" style-src 'unsafe-inline';"
48            b" media-src 'self';"
49            b" object-src 'self';",
50        )
51        # Limited non-standard form of CSP for IE11
52        request.setHeader(b"X-Content-Security-Policy", b"sandbox;")
53        request.setHeader(
54            b"Referrer-Policy",
55            b"no-referrer",
56        )
57        server_name, media_id, name = parse_media_id(request)
58        if server_name == self.server_name:
59            await self.media_repo.get_local_media(request, media_id, name)
60        else:
61            allow_remote = parse_boolean(request, "allow_remote", default=True)
62            if not allow_remote:
63                logger.info(
64                    "Rejecting request for remote media %s/%s due to allow_remote",
65                    server_name,
66                    media_id,
67                )
68                respond_404(request)
69                return
70
71            await self.media_repo.get_remote_media(request, server_name, media_id, name)
72