diff options
Diffstat (limited to '')
| -rw-r--r-- | synapse/rest/media/v1/_base.py | 18 | ||||
| -rw-r--r-- | synapse/rest/media/v1/filepath.py | 241 | ||||
| -rw-r--r-- | synapse/util/stringutils.py | 21 | ||||
| -rw-r--r-- | tests/http/test_endpoint.py | 3 | ||||
| -rw-r--r-- | tests/rest/media/v1/test_filepath.py | 250 |
5 files changed, 483 insertions, 50 deletions
diff --git a/synapse/rest/media/v1/_base.py b/synapse/rest/media/v1/_base.py index 014fa893d6..9b40fd8a6c 100644 --- a/synapse/rest/media/v1/_base.py +++ b/synapse/rest/media/v1/_base.py @@ -29,7 +29,7 @@ from synapse.api.errors import Codes, SynapseError, cs_error from synapse.http.server import finish_request, respond_with_json from synapse.http.site import SynapseRequest from synapse.logging.context import make_deferred_yieldable -from synapse.util.stringutils import is_ascii +from synapse.util.stringutils import is_ascii, parse_and_validate_server_name logger = logging.getLogger(__name__) @@ -51,6 +51,19 @@ TEXT_CONTENT_TYPES = [ def parse_media_id(request: Request) -> Tuple[str, str, Optional[str]]: + """Parses the server name, media ID and optional file name from the request URI + + Also performs some rough validation on the server name. + + Args: + request: The `Request`. + + Returns: + A tuple containing the parsed server name, media ID and optional file name. + + Raises: + SynapseError(404): if parsing or validation fail for any reason + """ try: # The type on postpath seems incorrect in Twisted 21.2.0. postpath: List[bytes] = request.postpath # type: ignore @@ -62,6 +75,9 @@ def parse_media_id(request: Request) -> Tuple[str, str, Optional[str]]: server_name = server_name_bytes.decode("utf-8") media_id = media_id_bytes.decode("utf8") + # Validate the server name, raising if invalid + parse_and_validate_server_name(server_name) + file_name = None if len(postpath) > 2: try: diff --git a/synapse/rest/media/v1/filepath.py b/synapse/rest/media/v1/filepath.py index bec77088ee..c0e15c6513 100644 --- a/synapse/rest/media/v1/filepath.py +++ b/synapse/rest/media/v1/filepath.py @@ -16,7 +16,8 @@ import functools import os import re -from typing import Any, Callable, List, TypeVar, cast +import string +from typing import Any, Callable, List, TypeVar, Union, cast NEW_FORMAT_ID_RE = re.compile(r"^\d\d\d\d-\d\d-\d\d") @@ -37,6 +38,85 @@ def _wrap_in_base_path(func: F) -> F: return cast(F, _wrapped) +GetPathMethod = TypeVar( + "GetPathMethod", bound=Union[Callable[..., str], Callable[..., List[str]]] +) + + +def _wrap_with_jail_check(func: GetPathMethod) -> GetPathMethod: + """Wraps a path-returning method to check that the returned path(s) do not escape + the media store directory. + + The check is not expected to ever fail, unless `func` is missing a call to + `_validate_path_component`, or `_validate_path_component` is buggy. + + Args: + func: The `MediaFilePaths` method to wrap. The method may return either a single + path, or a list of paths. Returned paths may be either absolute or relative. + + Returns: + The method, wrapped with a check to ensure that the returned path(s) lie within + the media store directory. Raises a `ValueError` if the check fails. + """ + + @functools.wraps(func) + def _wrapped( + self: "MediaFilePaths", *args: Any, **kwargs: Any + ) -> Union[str, List[str]]: + path_or_paths = func(self, *args, **kwargs) + + if isinstance(path_or_paths, list): + paths_to_check = path_or_paths + else: + paths_to_check = [path_or_paths] + + for path in paths_to_check: + # path may be an absolute or relative path, depending on the method being + # wrapped. When "appending" an absolute path, `os.path.join` discards the + # previous path, which is desired here. + normalized_path = os.path.normpath(os.path.join(self.real_base_path, path)) + if ( + os.path.commonpath([normalized_path, self.real_base_path]) + != self.real_base_path + ): + raise ValueError(f"Invalid media store path: {path!r}") + + return path_or_paths + + return cast(GetPathMethod, _wrapped) + + +ALLOWED_CHARACTERS = set( + string.ascii_letters + + string.digits + + "_-" + + ".[]:" # Domain names, IPv6 addresses and ports in server names +) +FORBIDDEN_NAMES = { + "", + os.path.curdir, # "." for the current platform + os.path.pardir, # ".." for the current platform +} + + +def _validate_path_component(name: str) -> str: + """Checks that the given string can be safely used as a path component + + Args: + name: The path component to check. + + Returns: + The path component if valid. + + Raises: + ValueError: If `name` cannot be safely used as a path component. + """ + if not ALLOWED_CHARACTERS.issuperset(name) or name in FORBIDDEN_NAMES: + raise ValueError(f"Invalid path component: {name!r}") + + return name + + class MediaFilePaths: """Describes where files are stored on disk. @@ -48,22 +128,46 @@ class MediaFilePaths: def __init__(self, primary_base_path: str): self.base_path = primary_base_path + # The media store directory, with all symlinks resolved. + self.real_base_path = os.path.realpath(primary_base_path) + + # Refuse to initialize if paths cannot be validated correctly for the current + # platform. + assert os.path.sep not in ALLOWED_CHARACTERS + assert os.path.altsep not in ALLOWED_CHARACTERS + # On Windows, paths have all sorts of weirdness which `_validate_path_component` + # does not consider. In any case, the remote media store can't work correctly + # for certain homeservers there, since ":"s aren't allowed in paths. + assert os.name == "posix" + + @_wrap_with_jail_check def local_media_filepath_rel(self, media_id: str) -> str: - return os.path.join("local_content", media_id[0:2], media_id[2:4], media_id[4:]) + return os.path.join( + "local_content", + _validate_path_component(media_id[0:2]), + _validate_path_component(media_id[2:4]), + _validate_path_component(media_id[4:]), + ) local_media_filepath = _wrap_in_base_path(local_media_filepath_rel) + @_wrap_with_jail_check def local_media_thumbnail_rel( self, media_id: str, width: int, height: int, content_type: str, method: str ) -> str: top_level_type, sub_type = content_type.split("/") file_name = "%i-%i-%s-%s-%s" % (width, height, top_level_type, sub_type, method) return os.path.join( - "local_thumbnails", media_id[0:2], media_id[2:4], media_id[4:], file_name + "local_thumbnails", + _validate_path_component(media_id[0:2]), + _validate_path_component(media_id[2:4]), + _validate_path_component(media_id[4:]), + _validate_path_component(file_name), ) local_media_thumbnail = _wrap_in_base_path(local_media_thumbnail_rel) + @_wrap_with_jail_check def local_media_thumbnail_dir(self, media_id: str) -> str: """ Retrieve the local store path of thumbnails of a given media_id @@ -76,18 +180,24 @@ class MediaFilePaths: return os.path.join( self.base_path, "local_thumbnails", - media_id[0:2], - media_id[2:4], - media_id[4:], + _validate_path_component(media_id[0:2]), + _validate_path_component(media_id[2:4]), + _validate_path_component(media_id[4:]), ) + @_wrap_with_jail_check def remote_media_filepath_rel(self, server_name: str, file_id: str) -> str: return os.path.join( - "remote_content", server_name, file_id[0:2], file_id[2:4], file_id[4:] + "remote_content", + _validate_path_component(server_name), + _validate_path_component(file_id[0:2]), + _validate_path_component(file_id[2:4]), + _validate_path_component(file_id[4:]), ) remote_media_filepath = _wrap_in_base_path(remote_media_filepath_rel) + @_wrap_with_jail_check def remote_media_thumbnail_rel( self, server_name: str, @@ -101,11 +211,11 @@ class MediaFilePaths: file_name = "%i-%i-%s-%s-%s" % (width, height, top_level_type, sub_type, method) return os.path.join( "remote_thumbnail", - server_name, - file_id[0:2], - file_id[2:4], - file_id[4:], - file_name, + _validate_path_component(server_name), + _validate_path_component(file_id[0:2]), + _validate_path_component(file_id[2:4]), + _validate_path_component(file_id[4:]), + _validate_path_component(file_name), ) remote_media_thumbnail = _wrap_in_base_path(remote_media_thumbnail_rel) @@ -113,6 +223,7 @@ class MediaFilePaths: # Legacy path that was used to store thumbnails previously. # Should be removed after some time, when most of the thumbnails are stored # using the new path. + @_wrap_with_jail_check def remote_media_thumbnail_rel_legacy( self, server_name: str, file_id: str, width: int, height: int, content_type: str ) -> str: @@ -120,43 +231,66 @@ class MediaFilePaths: file_name = "%i-%i-%s-%s" % (width, height, top_level_type, sub_type) return os.path.join( "remote_thumbnail", - server_name, - file_id[0:2], - file_id[2:4], - file_id[4:], - file_name, + _validate_path_component(server_name), + _validate_path_component(file_id[0:2]), + _validate_path_component(file_id[2:4]), + _validate_path_component(file_id[4:]), + _validate_path_component(file_name), ) def remote_media_thumbnail_dir(self, server_name: str, file_id: str) -> str: return os.path.join( self.base_path, "remote_thumbnail", - server_name, - file_id[0:2], - file_id[2:4], - file_id[4:], + _validate_path_component(server_name), + _validate_path_component(file_id[0:2]), + _validate_path_component(file_id[2:4]), + _validate_path_component(file_id[4:]), ) + @_wrap_with_jail_check def url_cache_filepath_rel(self, media_id: str) -> str: if NEW_FORMAT_ID_RE.match(media_id): # Media id is of the form <DATE><RANDOM_STRING> # E.g.: 2017-09-28-fsdRDt24DS234dsf - return os.path.join("url_cache", media_id[:10], media_id[11:]) + return os.path.join( + "url_cache", + _validate_path_component(media_id[:10]), + _validate_path_component(media_id[11:]), + ) else: - return os.path.join("url_cache", media_id[0:2], media_id[2:4], media_id[4:]) + return os.path.join( + "url_cache", + _validate_path_component(media_id[0:2]), + _validate_path_component(media_id[2:4]), + _validate_path_component(media_id[4:]), + ) url_cache_filepath = _wrap_in_base_path(url_cache_filepath_rel) + @_wrap_with_jail_check def url_cache_filepath_dirs_to_delete(self, media_id: str) -> List[str]: "The dirs to try and remove if we delete the media_id file" if NEW_FORMAT_ID_RE.match(media_id): - return [os.path.join(self.base_path, "url_cache", media_id[:10])] + return [ + os.path.join( + self.base_path, "url_cache", _validate_path_component(media_id[:10]) + ) + ] else: return [ - os.path.join(self.base_path, "url_cache", media_id[0:2], media_id[2:4]), - os.path.join(self.base_path, "url_cache", media_id[0:2]), + os.path.join( + self.base_path, + "url_cache", + _validate_path_component(media_id[0:2]), + _validate_path_component(media_id[2:4]), + ), + os.path.join( + self.base_path, "url_cache", _validate_path_component(media_id[0:2]) + ), ] + @_wrap_with_jail_check def url_cache_thumbnail_rel( self, media_id: str, width: int, height: int, content_type: str, method: str ) -> str: @@ -168,37 +302,46 @@ class MediaFilePaths: if NEW_FORMAT_ID_RE.match(media_id): return os.path.join( - "url_cache_thumbnails", media_id[:10], media_id[11:], file_name + "url_cache_thumbnails", + _validate_path_component(media_id[:10]), + _validate_path_component(media_id[11:]), + _validate_path_component(file_name), ) else: return os.path.join( "url_cache_thumbnails", - media_id[0:2], - media_id[2:4], - media_id[4:], - file_name, + _validate_path_component(media_id[0:2]), + _validate_path_component(media_id[2:4]), + _validate_path_component(media_id[4:]), + _validate_path_component(file_name), ) url_cache_thumbnail = _wrap_in_base_path(url_cache_thumbnail_rel) + @_wrap_with_jail_check def url_cache_thumbnail_directory_rel(self, media_id: str) -> str: # Media id is of the form <DATE><RANDOM_STRING> # E.g.: 2017-09-28-fsdRDt24DS234dsf if NEW_FORMAT_ID_RE.match(media_id): - return os.path.join("url_cache_thumbnails", media_id[:10], media_id[11:]) + return os.path.join( + "url_cache_thumbnails", + _validate_path_component(media_id[:10]), + _validate_path_component(media_id[11:]), + ) else: return os.path.join( "url_cache_thumbnails", - media_id[0:2], - media_id[2:4], - media_id[4:], + _validate_path_component(media_id[0:2]), + _validate_path_component(media_id[2:4]), + _validate_path_component(media_id[4:]), ) url_cache_thumbnail_directory = _wrap_in_base_path( url_cache_thumbnail_directory_rel ) + @_wrap_with_jail_check def url_cache_thumbnail_dirs_to_delete(self, media_id: str) -> List[str]: "The dirs to try and remove if we delete the media_id thumbnails" # Media id is of the form <DATE><RANDOM_STRING> @@ -206,21 +349,35 @@ class MediaFilePaths: if NEW_FORMAT_ID_RE.match(media_id): return [ os.path.join( - self.base_path, "url_cache_thumbnails", media_id[:10], media_id[11:] + self.base_path, + "url_cache_thumbnails", + _validate_path_component(media_id[:10]), + _validate_path_component(media_id[11:]), + ), + os.path.join( + self.base_path, + "url_cache_thumbnails", + _validate_path_component(media_id[:10]), ), - os.path.join(self.base_path, "url_cache_thumbnails", media_id[:10]), ] else: return [ os.path.join( self.base_path, "url_cache_thumbnails", - media_id[0:2], - media_id[2:4], - media_id[4:], + _validate_path_component(media_id[0:2]), + _validate_path_component(media_id[2:4]), + _validate_path_component(media_id[4:]), ), os.path.join( - self.base_path, "url_cache_thumbnails", media_id[0:2], media_id[2:4] + self.base_path, + "url_cache_thumbnails", + _validate_path_component(media_id[0:2]), + _validate_path_component(media_id[2:4]), + ), + os.path.join( + self.base_path, + "url_cache_thumbnails", + _validate_path_component(media_id[0:2]), ), - os.path.join(self.base_path, "url_cache_thumbnails", media_id[0:2]), ] diff --git a/synapse/util/stringutils.py b/synapse/util/stringutils.py index f029432191..ea1032b4fc 100644 --- a/synapse/util/stringutils.py +++ b/synapse/util/stringutils.py @@ -19,6 +19,8 @@ import string from collections.abc import Iterable from typing import Optional, Tuple +from netaddr import valid_ipv6 + from synapse.api.errors import Codes, SynapseError _string_with_symbols = string.digits + string.ascii_letters + ".,;:^&*-_+=#~@" @@ -97,7 +99,10 @@ def parse_server_name(server_name: str) -> Tuple[str, Optional[int]]: raise ValueError("Invalid server name '%s'" % server_name) -VALID_HOST_REGEX = re.compile("\\A[0-9a-zA-Z.-]+\\Z") +# An approximation of the domain name syntax in RFC 1035, section 2.3.1. +# NB: "\Z" is not equivalent to "$". +# The latter will match the position before a "\n" at the end of a string. +VALID_HOST_REGEX = re.compile("\\A[0-9a-zA-Z-]+(?:\\.[0-9a-zA-Z-]+)*\\Z") def parse_and_validate_server_name(server_name: str) -> Tuple[str, Optional[int]]: @@ -122,13 +127,15 @@ def parse_and_validate_server_name(server_name: str) -> Tuple[str, Optional[int] if host[0] == "[": if host[-1] != "]": raise ValueError("Mismatched [...] in server name '%s'" % (server_name,)) - return host, port - # otherwise it should only be alphanumerics. - if not VALID_HOST_REGEX.match(host): - raise ValueError( - "Server name '%s' contains invalid characters" % (server_name,) - ) + # valid_ipv6 raises when given an empty string + ipv6_address = host[1:-1] + if not ipv6_address or not valid_ipv6(ipv6_address): + raise ValueError( + "Server name '%s' is not a valid IPv6 address" % (server_name,) + ) + elif not VALID_HOST_REGEX.match(host): + raise ValueError("Server name '%s' has an invalid format" % (server_name,)) return host, port diff --git a/tests/http/test_endpoint.py b/tests/http/test_endpoint.py index 1f9a2f9b1d..c8cc21cadd 100644 --- a/tests/http/test_endpoint.py +++ b/tests/http/test_endpoint.py @@ -36,8 +36,11 @@ class ServerNameTestCase(unittest.TestCase): "localhost:http", # non-numeric port "1234]", # smells like ipv6 literal but isn't "[1234", + "[1.2.3.4]", "underscore_.com", "percent%65.com", + "newline.com\n", + ".empty-label.com", "1234:5678:80", # too many colons ] for i in test_data: diff --git a/tests/rest/media/v1/test_filepath.py b/tests/rest/media/v1/test_filepath.py index 09504a485f..8fe94f7d85 100644 --- a/tests/rest/media/v1/test_filepath.py +++ b/tests/rest/media/v1/test_filepath.py @@ -11,6 +11,9 @@ # 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 inspect +from typing import Iterable + from synapse.rest.media.v1.filepath import MediaFilePaths from tests import unittest @@ -236,3 +239,250 @@ class MediaFilePathsTestCase(unittest.TestCase): "/media_store/url_cache_thumbnails/Ge", ], ) + + def test_server_name_validation(self): + """Test validation of server names""" + self._test_path_validation( + [ + "remote_media_filepath_rel", + "remote_media_filepath", + "remote_media_thumbnail_rel", + "remote_media_thumbnail", + "remote_media_thumbnail_rel_legacy", + "remote_media_thumbnail_dir", + ], + parameter="server_name", + valid_values=[ + "matrix.org", + "matrix.org:8448", + "matrix-federation.matrix.org", + "matrix-federation.matrix.org:8448", + "10.1.12.123", + "10.1.12.123:8448", + "[fd00:abcd::ffff]", + "[fd00:abcd::ffff]:8448", + ], + invalid_values=[ + "/matrix.org", + "matrix.org/..", + "matrix.org\x00", + "", + ".", + "..", + "/", + ], + ) + + def test_file_id_validation(self): + """Test validation of local, remote and legacy URL cache file / media IDs""" + # File / media IDs get split into three parts to form paths, consisting of the + # first two characters, next two characters and rest of the ID. + valid_file_ids = [ + "GerZNDnDZVjsOtardLuwfIBg", + # Unexpected, but produces an acceptable path: + "GerZN", # "N" becomes the last directory + ] + invalid_file_ids = [ + "/erZNDnDZVjsOtardLuwfIBg", + "Ge/ZNDnDZVjsOtardLuwfIBg", + "GerZ/DnDZVjsOtardLuwfIBg", + "GerZ/..", + "G\x00rZNDnDZVjsOtardLuwfIBg", + "Ger\x00NDnDZVjsOtardLuwfIBg", + "GerZNDnDZVjsOtardLuwfIBg\x00", + "", + "Ge", + "GerZ", + "GerZ.", + "..rZNDnDZVjsOtardLuwfIBg", + "Ge..NDnDZVjsOtardLuwfIBg", + "GerZ..", + "GerZ/", + ] + + self._test_path_validation( + [ + "local_media_filepath_rel", + "local_media_filepath", + "local_media_thumbnail_rel", + "local_media_thumbnail", + "local_media_thumbnail_dir", + # Legacy URL cache media IDs + "url_cache_filepath_rel", + "url_cache_filepath", + # `url_cache_filepath_dirs_to_delete` is tested below. + "url_cache_thumbnail_rel", + "url_cache_thumbnail", + "url_cache_thumbnail_directory_rel", + "url_cache_thumbnail_directory", + "url_cache_thumbnail_dirs_to_delete", + ], + parameter="media_id", + valid_values=valid_file_ids, + invalid_values=invalid_file_ids, + ) + + # `url_cache_filepath_dirs_to_delete` ignores what would be the last path + # component, so only the first 4 characters matter. + self._test_path_validation( + [ + "url_cache_filepath_dirs_to_delete", + ], + parameter="media_id", + valid_values=valid_file_ids, + invalid_values=[ + "/erZNDnDZVjsOtardLuwfIBg", + "Ge/ZNDnDZVjsOtardLuwfIBg", + "G\x00rZNDnDZVjsOtardLuwfIBg", + "Ger\x00NDnDZVjsOtardLuwfIBg", + "", + "Ge", + "..rZNDnDZVjsOtardLuwfIBg", + "Ge..NDnDZVjsOtardLuwfIBg", + ], + ) + + self._test_path_validation( + [ + "remote_media_filepath_rel", + "remote_media_filepath", + "remote_media_thumbnail_rel", + "remote_media_thumbnail", + "remote_media_thumbnail_rel_legacy", + "remote_media_thumbnail_dir", + ], + parameter="file_id", + valid_values=valid_file_ids, + invalid_values=invalid_file_ids, + ) + + def test_url_cache_media_id_validation(self): + """Test validation of URL cache media IDs""" + self._test_path_validation( + [ + "url_cache_filepath_rel", + "url_cache_filepath", + # `url_cache_filepath_dirs_to_delete` only cares about the date prefix + "url_cache_thumbnail_rel", + "url_cache_thumbnail", + "url_cache_thumbnail_directory_rel", + "url_cache_thumbnail_directory", + "url_cache_thumbnail_dirs_to_delete", + ], + parameter="media_id", + valid_values=[ + "2020-01-02_GerZNDnDZVjsOtar", + "2020-01-02_G", # Unexpected, but produces an acceptable path + ], + invalid_values=[ + "2020-01-02", + "2020-01-02-", + "2020-01-02-.", + "2020-01-02-..", + "2020-01-02-/", + "2020-01-02-/GerZNDnDZVjsOtar", + "2020-01-02-GerZNDnDZVjsOtar/..", + "2020-01-02-GerZNDnDZVjsOtar\x00", + ], + ) + + def test_content_type_validation(self): + """Test validation of thumbnail content types""" + self._test_path_validation( + [ + "local_media_thumbnail_rel", + "local_media_thumbnail", + "remote_media_thumbnail_rel", + "remote_media_thumbnail", + "remote_media_thumbnail_rel_legacy", + "url_cache_thumbnail_rel", + "url_cache_thumbnail", + ], + parameter="content_type", + valid_values=[ + "image/jpeg", + ], + invalid_values=[ + "", # ValueError: not enough values to unpack + "image/jpeg/abc", # ValueError: too many values to unpack + "image/jpeg\x00", + ], + ) + + def test_thumbnail_method_validation(self): + """Test validation of thumbnail methods""" + self._test_path_validation( + [ + "local_media_thumbnail_rel", + "local_media_thumbnail", + "remote_media_thumbnail_rel", + "remote_media_thumbnail", + "url_cache_thumbnail_rel", + "url_cache_thumbnail", + ], + parameter="method", + valid_values=[ + "crop", + "scale", + ], + invalid_values=[ + "/scale", + "scale/..", + "scale\x00", + "/", + ], + ) + + def _test_path_validation( + self, + methods: Iterable[str], + parameter: str, + valid_values: Iterable[str], + invalid_values: Iterable[str], + ): + """Test that the specified methods validate the named parameter as expected + + Args: + methods: The names of `MediaFilePaths` methods to test + parameter: The name of the parameter to test + valid_values: A list of parameter values that are expected to be accepted + invalid_values: A list of parameter values that are expected to be rejected + + Raises: + AssertionError: If a value was accepted when it should have failed + validation. + ValueError: If a value failed validation when it should have been accepted. + """ + for method in methods: + get_path = getattr(self.filepaths, method) + + parameters = inspect.signature(get_path).parameters + kwargs = { + "server_name": "matrix.org", + "media_id": "GerZNDnDZVjsOtardLuwfIBg", + "file_id": "GerZNDnDZVjsOtardLuwfIBg", + "width": 800, + "height": 600, + "content_type": "image/jpeg", + "method": "scale", + } + + if get_path.__name__.startswith("url_"): + kwargs["media_id"] = "2020-01-02_GerZNDnDZVjsOtar" + + kwargs = {k: v for k, v in kwargs.items() if k in parameters} + kwargs.pop(parameter) + + for value in valid_values: + kwargs[parameter] = value + get_path(**kwargs) + # No exception should be raised + + for value in invalid_values: + with self.assertRaises(ValueError): + kwargs[parameter] = value + path_or_list = get_path(**kwargs) + self.fail( + f"{value!r} unexpectedly passed validation: " + f"{method} returned {path_or_list!r}" + ) |