Fix unsafe hotserving behaviour for non-multimedia uploads. (#15680)

* Fix unsafe hotserving behaviour for non-multimedia uploads.

* invert disposition assert

* test_media_storage.py: run lint

* test_base.py: /inline/attachment/s

* Only return attachment for disposition type, update tests

* Update synapse/media/_base.py

Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>

* Update changelog.d/15680.bugfix

Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>

* add attribution

* Update changelog.

---------

Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>
This commit is contained in:
Josh Qou 2023-06-15 14:23:27 +01:00 committed by GitHub
parent 1404f68a03
commit d939120421
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4 changed files with 29 additions and 19 deletions

1
changelog.d/15680.bugfix Normal file
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@ -0,0 +1 @@
Fix a long-standing bug where media files were served in an unsafe manner. Contributed by @joshqou.

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@ -152,6 +152,9 @@ def add_file_headers(
content_type = media_type
request.setHeader(b"Content-Type", content_type.encode("UTF-8"))
# Use a Content-Disposition of attachment to force download of media.
disposition = "attachment"
if upload_name:
# RFC6266 section 4.1 [1] defines both `filename` and `filename*`.
#
@ -173,11 +176,17 @@ def add_file_headers(
# correctly interpret those as of 0.99.2 and (b) they are a bit of a pain and we
# may as well just do the filename* version.
if _can_encode_filename_as_token(upload_name):
disposition = "inline; filename=%s" % (upload_name,)
disposition = "%s; filename=%s" % (
disposition,
upload_name,
)
else:
disposition = "inline; filename*=utf-8''%s" % (_quote(upload_name),)
disposition = "%s; filename*=utf-8''%s" % (
disposition,
_quote(upload_name),
)
request.setHeader(b"Content-Disposition", disposition.encode("ascii"))
request.setHeader(b"Content-Disposition", disposition.encode("ascii"))
# cache for at least a day.
# XXX: we might want to turn this off for data we don't want to

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@ -20,12 +20,12 @@ from tests import unittest
class GetFileNameFromHeadersTests(unittest.TestCase):
# input -> expected result
TEST_CASES = {
b"inline; filename=abc.txt": "abc.txt",
b'inline; filename="azerty"': "azerty",
b'inline; filename="aze%20rty"': "aze%20rty",
b'inline; filename="aze"rty"': 'aze"rty',
b'inline; filename="azer;ty"': "azer;ty",
b"inline; filename*=utf-8''foo%C2%A3bar": "foo£bar",
b"attachment; filename=abc.txt": "abc.txt",
b'attachment; filename="azerty"': "azerty",
b'attachment; filename="aze%20rty"': "aze%20rty",
b'attachment; filename="aze"rty"': 'aze"rty',
b'attachment; filename="azer;ty"': "azer;ty",
b"attachment; filename*=utf-8''foo%C2%A3bar": "foo£bar",
}
def tests(self) -> None:

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@ -317,7 +317,7 @@ class MediaRepoTests(unittest.HomeserverTestCase):
def test_handle_missing_content_type(self) -> None:
channel = self._req(
b"inline; filename=out" + self.test_image.extension,
b"attachment; filename=out" + self.test_image.extension,
include_content_type=False,
)
headers = channel.headers
@ -331,7 +331,7 @@ class MediaRepoTests(unittest.HomeserverTestCase):
If the filename is filename=<ascii> then Synapse will decode it as an
ASCII string, and use filename= in the response.
"""
channel = self._req(b"inline; filename=out" + self.test_image.extension)
channel = self._req(b"attachment; filename=out" + self.test_image.extension)
headers = channel.headers
self.assertEqual(
@ -339,7 +339,7 @@ class MediaRepoTests(unittest.HomeserverTestCase):
)
self.assertEqual(
headers.getRawHeaders(b"Content-Disposition"),
[b"inline; filename=out" + self.test_image.extension],
[b"attachment; filename=out" + self.test_image.extension],
)
def test_disposition_filenamestar_utf8escaped(self) -> None:
@ -350,7 +350,7 @@ class MediaRepoTests(unittest.HomeserverTestCase):
"""
filename = parse.quote("\u2603".encode()).encode("ascii")
channel = self._req(
b"inline; filename*=utf-8''" + filename + self.test_image.extension
b"attachment; filename*=utf-8''" + filename + self.test_image.extension
)
headers = channel.headers
@ -359,13 +359,13 @@ class MediaRepoTests(unittest.HomeserverTestCase):
)
self.assertEqual(
headers.getRawHeaders(b"Content-Disposition"),
[b"inline; filename*=utf-8''" + filename + self.test_image.extension],
[b"attachment; filename*=utf-8''" + filename + self.test_image.extension],
)
def test_disposition_none(self) -> None:
"""
If there is no filename, one isn't passed on in the Content-Disposition
of the request.
If there is no filename, Content-Disposition should only
be a disposition type.
"""
channel = self._req(None)
@ -373,7 +373,7 @@ class MediaRepoTests(unittest.HomeserverTestCase):
self.assertEqual(
headers.getRawHeaders(b"Content-Type"), [self.test_image.content_type]
)
self.assertEqual(headers.getRawHeaders(b"Content-Disposition"), None)
self.assertEqual(headers.getRawHeaders(b"Content-Disposition"), [b"attachment"])
def test_thumbnail_crop(self) -> None:
"""Test that a cropped remote thumbnail is available."""
@ -612,7 +612,7 @@ class MediaRepoTests(unittest.HomeserverTestCase):
Tests that the `X-Robots-Tag` header is present, which informs web crawlers
to not index, archive, or follow links in media.
"""
channel = self._req(b"inline; filename=out" + self.test_image.extension)
channel = self._req(b"attachment; filename=out" + self.test_image.extension)
headers = channel.headers
self.assertEqual(
@ -625,7 +625,7 @@ class MediaRepoTests(unittest.HomeserverTestCase):
Test that the Cross-Origin-Resource-Policy header is set to "cross-origin"
allowing web clients to embed media from the downloads API.
"""
channel = self._req(b"inline; filename=out" + self.test_image.extension)
channel = self._req(b"attachment; filename=out" + self.test_image.extension)
headers = channel.headers