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Uniformize spam-checker API, part 4: port other spam-checker callbacks to return Union[Allow, Codes]. (#12857)

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Co-authored-by: Brendan Abolivier <babolivier@matrix.org>
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1
changelog.d/12857.feature Normal file
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@ -0,0 +1 @@
Port spam-checker API callbacks to a new, richer API. This is part of an ongoing change to let spam-checker modules inform users of the reason their event or operation is rejected.

190
docs/modules/spam_checker_callbacks.md
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@ -38,15 +38,13 @@ this callback.
_First introduced in Synapse v1.37.0_
_Changed in Synapse v1.61.0: `synapse.module_api.NOT_SPAM` and `synapse.module_api.errors.Codes` can be returned by this callback. Returning a boolean is now deprecated._
```python
async def user_may_join_room(user: str, room: str, is_invited: bool) -> bool
async def user_may_join_room(user: str, room: str, is_invited: bool) -> Union["synapse.module_api.NOT_SPAM", "synapse.module_api.errors.Codes", bool]
```
Called when a user is trying to join a room. The module must return a `bool` to indicate
whether the user can join the room. Return `False` to prevent the user from joining the
room; otherwise return `True` to permit the joining.
The user is represented by their Matrix user ID (e.g.
Called when a user is trying to join a room. The user is represented by their Matrix user ID (e.g.
`@alice:example.com`) and the room is represented by its Matrix ID (e.g.
`!room:example.com`). The module is also given a boolean to indicate whether the user
currently has a pending invite in the room.
@ -54,46 +52,67 @@ currently has a pending invite in the room.
This callback isn't called if the join is performed by a server administrator, or in the
context of a room creation.
The callback must return one of:
- `synapse.module_api.NOT_SPAM`, to allow the operation. Other callbacks may still
decide to reject it.
- `synapse.module_api.errors.Codes` to reject the operation with an error code. In case
of doubt, `synapse.module_api.errors.Codes.FORBIDDEN` is a good error code.
- (deprecated) `False`, which is the same as returning `synapse.module_api.NOT_SPAM`.
- (deprecated) `True`, which is the same as returning `synapse.module_api.errors.Codes.FORBIDDEN`.
If multiple modules implement this callback, they will be considered in order. If a
callback returns `True`, Synapse falls through to the next one. The value of the first
callback that does not return `True` will be used. If this happens, Synapse will not call
any of the subsequent implementations of this callback.
callback returns `synapse.module_api.NOT_SPAM`, Synapse falls through to the next one.
The value of the first callback that does not return `synapse.module_api.NOT_SPAM` will
be used. If this happens, Synapse will not call any of the subsequent implementations of
this callback.
### `user_may_invite`
_First introduced in Synapse v1.37.0_
_Changed in Synapse v1.61.0: `synapse.module_api.NOT_SPAM` and `synapse.module_api.errors.Codes` can be returned by this callback. Returning a boolean is now deprecated._
```python
async def user_may_invite(inviter: str, invitee: str, room_id: str) -> bool
async def user_may_invite(inviter: str, invitee: str, room_id: str) -> Union["synapse.module_api.NOT_SPAM", "synapse.module_api.errors.Codes", bool]
```
Called when processing an invitation. The module must return a `bool` indicating whether
the inviter can invite the invitee to the given room. Both inviter and invitee are
represented by their Matrix user ID (e.g. `@alice:example.com`). Return `False` to prevent
the invitation; otherwise return `True` to permit it.
Called when processing an invitation. Both inviter and invitee are
represented by their Matrix user ID (e.g. `@alice:example.com`).
The callback must return one of:
- `synapse.module_api.NOT_SPAM`, to allow the operation. Other callbacks may still
decide to reject it.
- `synapse.module_api.errors.Codes` to reject the operation with an error code. In case
of doubt, `synapse.module_api.errors.Codes.FORBIDDEN` is a good error code.
- (deprecated) `False`, which is the same as returning `synapse.module_api.NOT_SPAM`.
- (deprecated) `True`, which is the same as returning `synapse.module_api.errors.Codes.FORBIDDEN`.
If multiple modules implement this callback, they will be considered in order. If a
callback returns `True`, Synapse falls through to the next one. The value of the first
callback that does not return `True` will be used. If this happens, Synapse will not call
any of the subsequent implementations of this callback.
callback returns `synapse.module_api.NOT_SPAM`, Synapse falls through to the next one.
The value of the first callback that does not return `synapse.module_api.NOT_SPAM` will
be used. If this happens, Synapse will not call any of the subsequent implementations of
this callback.
### `user_may_send_3pid_invite`
_First introduced in Synapse v1.45.0_
_Changed in Synapse v1.61.0: `synapse.module_api.NOT_SPAM` and `synapse.module_api.errors.Codes` can be returned by this callback. Returning a boolean is now deprecated._
```python
async def user_may_send_3pid_invite(
inviter: str,
medium: str,
address: str,
room_id: str,
) -> bool
) -> Union["synapse.module_api.NOT_SPAM", "synapse.module_api.errors.Codes", bool]
```
Called when processing an invitation using a third-party identifier (also called a 3PID,
e.g. an email address or a phone number). The module must return a `bool` indicating
whether the inviter can invite the invitee to the given room. Return `False` to prevent
the invitation; otherwise return `True` to permit it.
e.g. an email address or a phone number).
The inviter is represented by their Matrix user ID (e.g. `@alice:example.com`), and the
invitee is represented by its medium (e.g. "email") and its address
@ -115,63 +134,108 @@ await user_may_send_3pid_invite(
**Note**: If the third-party identifier is already associated with a matrix user ID,
[`user_may_invite`](#user_may_invite) will be used instead.
The callback must return one of:
- `synapse.module_api.NOT_SPAM`, to allow the operation. Other callbacks may still
decide to reject it.
- `synapse.module_api.errors.Codes` to reject the operation with an error code. In case
of doubt, `synapse.module_api.errors.Codes.FORBIDDEN` is a good error code.
- (deprecated) `False`, which is the same as returning `synapse.module_api.NOT_SPAM`.
- (deprecated) `True`, which is the same as returning `synapse.module_api.errors.Codes.FORBIDDEN`.
If multiple modules implement this callback, they will be considered in order. If a
callback returns `True`, Synapse falls through to the next one. The value of the first
callback that does not return `True` will be used. If this happens, Synapse will not call
any of the subsequent implementations of this callback.
callback returns `synapse.module_api.NOT_SPAM`, Synapse falls through to the next one.
The value of the first callback that does not return `synapse.module_api.NOT_SPAM` will
be used. If this happens, Synapse will not call any of the subsequent implementations of
this callback.
### `user_may_create_room`
_First introduced in Synapse v1.37.0_
_Changed in Synapse v1.61.0: `synapse.module_api.NOT_SPAM` and `synapse.module_api.errors.Codes` can be returned by this callback. Returning a boolean is now deprecated._
```python
async def user_may_create_room(user: str) -> bool
async def user_may_create_room(user_id: str) -> Union["synapse.module_api.NOT_SPAM", "synapse.module_api.errors.Codes", bool]
```
Called when processing a room creation request. The module must return a `bool` indicating
whether the given user (represented by their Matrix user ID) is allowed to create a room.
Return `False` to prevent room creation; otherwise return `True` to permit it.
Called when processing a room creation request.
The callback must return one of:
- `synapse.module_api.NOT_SPAM`, to allow the operation. Other callbacks may still
decide to reject it.
- `synapse.module_api.errors.Codes` to reject the operation with an error code. In case
of doubt, `synapse.module_api.errors.Codes.FORBIDDEN` is a good error code.
- (deprecated) `False`, which is the same as returning `synapse.module_api.NOT_SPAM`.
- (deprecated) `True`, which is the same as returning `synapse.module_api.errors.Codes.FORBIDDEN`.
If multiple modules implement this callback, they will be considered in order. If a
callback returns `True`, Synapse falls through to the next one. The value of the first
callback that does not return `True` will be used. If this happens, Synapse will not call
any of the subsequent implementations of this callback.
callback returns `synapse.module_api.NOT_SPAM`, Synapse falls through to the next one.
The value of the first callback that does not return `synapse.module_api.NOT_SPAM` will
be used. If this happens, Synapse will not call any of the subsequent implementations of
this callback.
### `user_may_create_room_alias`
_First introduced in Synapse v1.37.0_
_Changed in Synapse v1.61.0: `synapse.module_api.NOT_SPAM` and `synapse.module_api.errors.Codes` can be returned by this callback. Returning a boolean is now deprecated._
```python
async def user_may_create_room_alias(user: str, room_alias: "synapse.types.RoomAlias") -> bool
async def user_may_create_room_alias(user_id: str, room_alias: "synapse.module_api.RoomAlias") -> Union["synapse.module_api.NOT_SPAM", "synapse.module_api.errors.Codes", bool]
```
Called when trying to associate an alias with an existing room. The module must return a
`bool` indicating whether the given user (represented by their Matrix user ID) is allowed
to set the given alias. Return `False` to prevent the alias creation; otherwise return
`True` to permit it.
Called when trying to associate an alias with an existing room.
The callback must return one of:
- `synapse.module_api.NOT_SPAM`, to allow the operation. Other callbacks may still
decide to reject it.
- `synapse.module_api.errors.Codes` to reject the operation with an error code. In case
of doubt, `synapse.module_api.errors.Codes.FORBIDDEN` is a good error code.
- (deprecated) `False`, which is the same as returning `synapse.module_api.NOT_SPAM`.
- (deprecated) `True`, which is the same as returning `synapse.module_api.errors.Codes.FORBIDDEN`.
If multiple modules implement this callback, they will be considered in order. If a
callback returns `True`, Synapse falls through to the next one. The value of the first
callback that does not return `True` will be used. If this happens, Synapse will not call
any of the subsequent implementations of this callback.
callback returns `synapse.module_api.NOT_SPAM`, Synapse falls through to the next one.
The value of the first callback that does not return `synapse.module_api.NOT_SPAM` will
be used. If this happens, Synapse will not call any of the subsequent implementations of
this callback.
### `user_may_publish_room`
_First introduced in Synapse v1.37.0_
_Changed in Synapse v1.61.0: `synapse.module_api.NOT_SPAM` and `synapse.module_api.errors.Codes` can be returned by this callback. Returning a boolean is now deprecated._
```python
async def user_may_publish_room(user: str, room_id: str) -> bool
async def user_may_publish_room(user_id: str, room_id: str) -> Union["synapse.module_api.NOT_SPAM", "synapse.module_api.errors.Codes", bool]
```
Called when trying to publish a room to the homeserver's public rooms directory. The
module must return a `bool` indicating whether the given user (represented by their
Matrix user ID) is allowed to publish the given room. Return `False` to prevent the
room from being published; otherwise return `True` to permit its publication.
Called when trying to publish a room to the homeserver's public rooms directory.
The callback must return one of:
- `synapse.module_api.NOT_SPAM`, to allow the operation. Other callbacks may still
decide to reject it.
- `synapse.module_api.errors.Codes` to reject the operation with an error code. In case
of doubt, `synapse.module_api.errors.Codes.FORBIDDEN` is a good error code.
- (deprecated) `False`, which is the same as returning `synapse.module_api.NOT_SPAM`.
- (deprecated) `True`, which is the same as returning `synapse.module_api.errors.Codes.FORBIDDEN`.
If multiple modules implement this callback, they will be considered in order. If a
callback returns `True`, Synapse falls through to the next one. The value of the first
callback that does not return `True` will be used. If this happens, Synapse will not call
any of the subsequent implementations of this callback.
callback returns `synapse.module_api.NOT_SPAM`, Synapse falls through to the next one.
The value of the first callback that does not return `synapse.module_api.NOT_SPAM` will
be used. If this happens, Synapse will not call any of the subsequent implementations of
this callback.
### `check_username_for_spam`
@ -239,21 +303,32 @@ this callback.
_First introduced in Synapse v1.37.0_
_Changed in Synapse v1.61.0: `synapse.module_api.NOT_SPAM` and `synapse.module_api.errors.Codes` can be returned by this callback. Returning a boolean is now deprecated._
```python
async def check_media_file_for_spam(
file_wrapper: "synapse.rest.media.v1.media_storage.ReadableFileWrapper",
file_info: "synapse.rest.media.v1._base.FileInfo",
) -> bool
) -> Union["synapse.module_api.NOT_SPAM", "synapse.module_api.errors.Codes", bool]
```
Called when storing a local or remote file. The module must return a `bool` indicating
whether the given file should be excluded from the homeserver's media store. Return
`True` to prevent this file from being stored; otherwise return `False`.
Called when storing a local or remote file.
The callback must return one of:
- `synapse.module_api.NOT_SPAM`, to allow the operation. Other callbacks may still
decide to reject it.
- `synapse.module_api.errors.Codes` to reject the operation with an error code. In case
of doubt, `synapse.module_api.errors.Codes.FORBIDDEN` is a good error code.
- (deprecated) `False`, which is the same as returning `synapse.module_api.NOT_SPAM`.
- (deprecated) `True`, which is the same as returning `synapse.module_api.errors.Codes.FORBIDDEN`.
If multiple modules implement this callback, they will be considered in order. If a
callback returns `False`, Synapse falls through to the next one. The value of the first
callback that does not return `False` will be used. If this happens, Synapse will not call
any of the subsequent implementations of this callback.
callback returns `synapse.module_api.NOT_SPAM`, Synapse falls through to the next one.
The value of the first callback that does not return `synapse.module_api.NOT_SPAM` will
be used. If this happens, Synapse will not call any of the subsequent implementations of
this callback.
### `should_drop_federated_event`
@ -316,6 +391,9 @@ class ListSpamChecker:
resource=IsUserEvilResource(config),
)
async def check_event_for_spam(self, event: "synapse.events.EventBase") -> Union[bool, str]:
return event.sender not in self.evil_users
async def check_event_for_spam(self, event: "synapse.events.EventBase") -> Union[Literal["NOT_SPAM"], Codes]:
if event.sender in self.evil_users:
return Codes.FORBIDDEN
else:
return synapse.module_api.NOT_SPAM
```

41
docs/upgrade.md
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@ -89,6 +89,47 @@ process, for example:
dpkg -i matrix-synapse-py3_1.3.0+stretch1_amd64.deb
```
# Upgrading to v1.61.0
## New signatures for spam checker callbacks
As a followup to changes in v1.60.0, the following spam-checker callbacks have changed signature:
- `user_may_join_room`
- `user_may_invite`
- `user_may_send_3pid_invite`
- `user_may_create_room`
- `user_may_create_room_alias`
- `user_may_publish_room`
- `check_media_file_for_spam`
For each of these methods, the previous callback signature has been deprecated.
Whereas callbacks used to return `bool`, they should now return `Union["synapse.module_api.NOT_SPAM", "synapse.module_api.errors.Codes"]`.
For instance, if your module implements `user_may_join_room` as follows:
```python
async def user_may_join_room(self, user_id: str, room_id: str, is_invited: bool)
if ...:
# Request is spam
return False
# Request is not spam
return True
```
you should rewrite it as follows:
```python
async def user_may_join_room(self, user_id: str, room_id: str, is_invited: bool)
if ...:
# Request is spam, mark it as forbidden (you may use some more precise error
# code if it is useful).
return synapse.module_api.errors.Codes.FORBIDDEN
# Request is not spam, mark it as such.
return synapse.module_api.NOT_SPAM
```
# Upgrading to v1.60.0
## Adding a new unique index to `state_group_edges` could fail if your database is corrupted

277
synapse/events/spamcheck.py
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@ -28,7 +28,10 @@ from typing import (
Union,
)
from synapse.api.errors import Codes
# `Literal` appears with Python 3.8.
from typing_extensions import Literal
import synapse
from synapse.rest.media.v1._base import FileInfo
from synapse.rest.media.v1.media_storage import ReadableFileWrapper
from synapse.spam_checker_api import RegistrationBehaviour
@ -47,12 +50,12 @@ CHECK_EVENT_FOR_SPAM_CALLBACK = Callable[
Awaitable[
Union[
str,
Codes,
"synapse.api.errors.Codes",
# Highly experimental, not officially part of the spamchecker API, may
# disappear without warning depending on the results of ongoing
# experiments.
# Use this to return additional information as part of an error.
Tuple[Codes, Dict],
Tuple["synapse.api.errors.Codes", Dict],
# Deprecated
bool,
]
@ -62,12 +65,72 @@ SHOULD_DROP_FEDERATED_EVENT_CALLBACK = Callable[
["synapse.events.EventBase"],
Awaitable[Union[bool, str]],
]
USER_MAY_JOIN_ROOM_CALLBACK = Callable[[str, str, bool], Awaitable[bool]]
USER_MAY_INVITE_CALLBACK = Callable[[str, str, str], Awaitable[bool]]
USER_MAY_SEND_3PID_INVITE_CALLBACK = Callable[[str, str, str, str], Awaitable[bool]]
USER_MAY_CREATE_ROOM_CALLBACK = Callable[[str], Awaitable[bool]]
USER_MAY_CREATE_ROOM_ALIAS_CALLBACK = Callable[[str, RoomAlias], Awaitable[bool]]
USER_MAY_PUBLISH_ROOM_CALLBACK = Callable[[str, str], Awaitable[bool]]
USER_MAY_JOIN_ROOM_CALLBACK = Callable[
[str, str, bool],
Awaitable[
Union[
Literal["NOT_SPAM"],
"synapse.api.errors.Codes",
# Deprecated
bool,
]
],
]
USER_MAY_INVITE_CALLBACK = Callable[
[str, str, str],
Awaitable[
Union[
Literal["NOT_SPAM"],
"synapse.api.errors.Codes",
# Deprecated
bool,
]
],
]
USER_MAY_SEND_3PID_INVITE_CALLBACK = Callable[
[str, str, str, str],
Awaitable[
Union[
Literal["NOT_SPAM"],
"synapse.api.errors.Codes",
# Deprecated
bool,
]
],
]
USER_MAY_CREATE_ROOM_CALLBACK = Callable[
[str],
Awaitable[
Union[
Literal["NOT_SPAM"],
"synapse.api.errors.Codes",
# Deprecated
bool,
]
],
]
USER_MAY_CREATE_ROOM_ALIAS_CALLBACK = Callable[
[str, RoomAlias],
Awaitable[
Union[
Literal["NOT_SPAM"],
"synapse.api.errors.Codes",
# Deprecated
bool,
]
],
]
USER_MAY_PUBLISH_ROOM_CALLBACK = Callable[
[str, str],
Awaitable[
Union[
Literal["NOT_SPAM"],
"synapse.api.errors.Codes",
# Deprecated
bool,
]
],
]
CHECK_USERNAME_FOR_SPAM_CALLBACK = Callable[[UserProfile], Awaitable[bool]]
LEGACY_CHECK_REGISTRATION_FOR_SPAM_CALLBACK = Callable[
[
@ -88,7 +151,14 @@ CHECK_REGISTRATION_FOR_SPAM_CALLBACK = Callable[
]
CHECK_MEDIA_FILE_FOR_SPAM_CALLBACK = Callable[
[ReadableFileWrapper, FileInfo],
Awaitable[bool],
Awaitable[
Union[
Literal["NOT_SPAM"],
"synapse.api.errors.Codes",
# Deprecated
bool,
]
],
]
@ -181,7 +251,7 @@ def load_legacy_spam_checkers(hs: "synapse.server.HomeServer") -> None:
class SpamChecker:
NOT_SPAM = "NOT_SPAM"
NOT_SPAM: Literal["NOT_SPAM"] = "NOT_SPAM"
def __init__(self, hs: "synapse.server.HomeServer") -> None:
self.hs = hs
@ -275,7 +345,7 @@ class SpamChecker:
async def check_event_for_spam(
self, event: "synapse.events.EventBase"
) -> Union[Tuple[Codes, Dict], str]:
) -> Union[Tuple["synapse.api.errors.Codes", Dict], str]:
"""Checks if a given event is considered "spammy" by this server.
If the server considers an event spammy, then it will be rejected if
@ -306,7 +376,7 @@ class SpamChecker:
elif res is True:
# This spam-checker rejects the event with deprecated
# return value `True`
return Codes.FORBIDDEN
return (synapse.api.errors.Codes.FORBIDDEN, {})
elif not isinstance(res, str):
# mypy complains that we can't reach this code because of the
# return type in CHECK_EVENT_FOR_SPAM_CALLBACK, but we don't know
@ -352,7 +422,7 @@ class SpamChecker:
async def user_may_join_room(
self, user_id: str, room_id: str, is_invited: bool
) -> bool:
) -> Union["synapse.api.errors.Codes", Literal["NOT_SPAM"]]:
"""Checks if a given users is allowed to join a room.
Not called when a user creates a room.
@ -362,54 +432,70 @@ class SpamChecker:
is_invited: Whether the user is invited into the room
Returns:
Whether the user may join the room
NOT_SPAM if the operation is permitted, Codes otherwise.
"""
for callback in self._user_may_join_room_callbacks:
with Measure(
self.clock, "{}.{}".format(callback.__module__, callback.__qualname__)
):
may_join_room = await delay_cancellation(
callback(user_id, room_id, is_invited)
)
if may_join_room is False:
return False
res = await delay_cancellation(callback(user_id, room_id, is_invited))
# Normalize return values to `Codes` or `"NOT_SPAM"`.
if res is True or res is self.NOT_SPAM:
continue
elif res is False:
return synapse.api.errors.Codes.FORBIDDEN
elif isinstance(res, synapse.api.errors.Codes):
return res
else:
logger.warning(
"Module returned invalid value, rejecting join as spam"
)
return synapse.api.errors.Codes.FORBIDDEN
return True
# No spam-checker has rejected the request, let it pass.
return self.NOT_SPAM
async def user_may_invite(
self, inviter_userid: str, invitee_userid: str, room_id: str
) -> bool:
) -> Union["synapse.api.errors.Codes", Literal["NOT_SPAM"]]:
"""Checks if a given user may send an invite
If this method returns false, the invite will be rejected.
Args:
inviter_userid: The user ID of the sender of the invitation
invitee_userid: The user ID targeted in the invitation
room_id: The room ID
Returns:
True if the user may send an invite, otherwise False
NOT_SPAM if the operation is permitted, Codes otherwise.
"""
for callback in self._user_may_invite_callbacks:
with Measure(
self.clock, "{}.{}".format(callback.__module__, callback.__qualname__)
):
may_invite = await delay_cancellation(
res = await delay_cancellation(
callback(inviter_userid, invitee_userid, room_id)
)
if may_invite is False:
return False
# Normalize return values to `Codes` or `"NOT_SPAM"`.
if res is True or res is self.NOT_SPAM:
continue
elif res is False:
return synapse.api.errors.Codes.FORBIDDEN
elif isinstance(res, synapse.api.errors.Codes):
return res
else:
logger.warning(
"Module returned invalid value, rejecting invite as spam"
)
return synapse.api.errors.Codes.FORBIDDEN
return True
# No spam-checker has rejected the request, let it pass.
return self.NOT_SPAM
async def user_may_send_3pid_invite(
self, inviter_userid: str, medium: str, address: str, room_id: str
) -> bool:
) -> Union["synapse.api.errors.Codes", Literal["NOT_SPAM"]]:
"""Checks if a given user may invite a given threepid into the room
If this method returns false, the threepid invite will be rejected.
Note that if the threepid is already associated with a Matrix user ID, Synapse
will call user_may_invite with said user ID instead.
@ -420,88 +506,113 @@ class SpamChecker:
room_id: The room ID
Returns:
True if the user may send the invite, otherwise False
NOT_SPAM if the operation is permitted, Codes otherwise.
"""
for callback in self._user_may_send_3pid_invite_callbacks:
with Measure(
self.clock, "{}.{}".format(callback.__module__, callback.__qualname__)
):
may_send_3pid_invite = await delay_cancellation(
res = await delay_cancellation(
callback(inviter_userid, medium, address, room_id)
)
if may_send_3pid_invite is False:
return False
# Normalize return values to `Codes` or `"NOT_SPAM"`.
if res is True or res is self.NOT_SPAM:
continue
elif res is False:
return synapse.api.errors.Codes.FORBIDDEN
elif isinstance(res, synapse.api.errors.Codes):
return res
else:
logger.warning(
"Module returned invalid value, rejecting 3pid invite as spam"
)
return synapse.api.errors.Codes.FORBIDDEN
return True
return self.NOT_SPAM
async def user_may_create_room(self, userid: str) -> bool:
async def user_may_create_room(
self, userid: str
) -> Union["synapse.api.errors.Codes", Literal["NOT_SPAM"]]:
"""Checks if a given user may create a room
If this method returns false, the creation request will be rejected.
Args:
userid: The ID of the user attempting to create a room
Returns:
True if the user may create a room, otherwise False
"""
for callback in self._user_may_create_room_callbacks:
with Measure(
self.clock, "{}.{}".format(callback.__module__, callback.__qualname__)
):
may_create_room = await delay_cancellation(callback(userid))
if may_create_room is False:
return False
res = await delay_cancellation(callback(userid))
if res is True or res is self.NOT_SPAM:
continue
elif res is False:
return synapse.api.errors.Codes.FORBIDDEN
elif isinstance(res, synapse.api.errors.Codes):
return res
else:
logger.warning(
"Module returned invalid value, rejecting room creation as spam"
)
return synapse.api.errors.Codes.FORBIDDEN
return True
return self.NOT_SPAM
async def user_may_create_room_alias(
self, userid: str, room_alias: RoomAlias
) -> bool:
) -> Union["synapse.api.errors.Codes", Literal["NOT_SPAM"]]:
"""Checks if a given user may create a room alias
If this method returns false, the association request will be rejected.
Args:
userid: The ID of the user attempting to create a room alias
room_alias: The alias to be created
Returns:
True if the user may create a room alias, otherwise False
"""
for callback in self._user_may_create_room_alias_callbacks:
with Measure(
self.clock, "{}.{}".format(callback.__module__, callback.__qualname__)
):
may_create_room_alias = await delay_cancellation(
callback(userid, room_alias)
)
if may_create_room_alias is False:
return False
res = await delay_cancellation(callback(userid, room_alias))
if res is True or res is self.NOT_SPAM:
continue
elif res is False:
return synapse.api.errors.Codes.FORBIDDEN
elif isinstance(res, synapse.api.errors.Codes):
return res
else:
logger.warning(
"Module returned invalid value, rejecting room create as spam"
)
return synapse.api.errors.Codes.FORBIDDEN
return True
return self.NOT_SPAM
async def user_may_publish_room(self, userid: str, room_id: str) -> bool:
async def user_may_publish_room(
self, userid: str, room_id: str
) -> Union["synapse.api.errors.Codes", Literal["NOT_SPAM"]]:
"""Checks if a given user may publish a room to the directory
If this method returns false, the publish request will be rejected.
Args:
userid: The user ID attempting to publish the room
room_id: The ID of the room that would be published
Returns:
True if the user may publish the room, otherwise False
"""
for callback in self._user_may_publish_room_callbacks:
with Measure(
self.clock, "{}.{}".format(callback.__module__, callback.__qualname__)
):
may_publish_room = await delay_cancellation(callback(userid, room_id))
if may_publish_room is False:
return False
res = await delay_cancellation(callback(userid, room_id))
if res is True or res is self.NOT_SPAM:
continue
elif res is False:
return synapse.api.errors.Codes.FORBIDDEN
elif isinstance(res, synapse.api.errors.Codes):
return res
else:
logger.warning(
"Module returned invalid value, rejecting room publication as spam"
)
return synapse.api.errors.Codes.FORBIDDEN
return True
return self.NOT_SPAM
async def check_username_for_spam(self, user_profile: UserProfile) -> bool:
"""Checks if a user ID or display name are considered "spammy" by this server.
@ -567,7 +678,7 @@ class SpamChecker:
async def check_media_file_for_spam(
self, file_wrapper: ReadableFileWrapper, file_info: FileInfo
) -> bool:
) -> Union["synapse.api.errors.Codes", Literal["NOT_SPAM"]]:
"""Checks if a piece of newly uploaded media should be blocked.
This will be called for local uploads, downloads of remote media, each
@ -580,31 +691,37 @@ class SpamChecker:
async def check_media_file_for_spam(
self, file: ReadableFileWrapper, file_info: FileInfo
) -> bool:
) -> Union[Codes, Literal["NOT_SPAM"]]:
buffer = BytesIO()
await file.write_chunks_to(buffer.write)
if buffer.getvalue() == b"Hello World":
return True
return synapse.module_api.NOT_SPAM
return False
return Codes.FORBIDDEN
Args:
file: An object that allows reading the contents of the media.
file_info: Metadata about the file.
Returns:
True if the media should be blocked or False if it should be
allowed.
"""
for callback in self._check_media_file_for_spam_callbacks:
with Measure(
self.clock, "{}.{}".format(callback.__module__, callback.__qualname__)
):
spam = await delay_cancellation(callback(file_wrapper, file_info))
if spam:
return True
res = await delay_cancellation(callback(file_wrapper, file_info))
# Normalize return values to `Codes` or `"NOT_SPAM"`.
if res is False or res is self.NOT_SPAM:
continue
elif res is True:
return synapse.api.errors.Codes.FORBIDDEN
elif isinstance(res, synapse.api.errors.Codes):
return res
else:
logger.warning(
"Module returned invalid value, rejecting media file as spam"
)
return synapse.api.errors.Codes.FORBIDDEN
return False
return self.NOT_SPAM

19
synapse/handlers/directory.py
View File

@ -28,6 +28,7 @@ from synapse.api.errors import (
SynapseError,
)
from synapse.appservice import ApplicationService
from synapse.module_api import NOT_SPAM
from synapse.storage.databases.main.directory import RoomAliasMapping
from synapse.types import JsonDict, Requester, RoomAlias, UserID, get_domain_from_id
@ -141,10 +142,15 @@ class DirectoryHandler:
403, "You must be in the room to create an alias for it"
)
if not await self.spam_checker.user_may_create_room_alias(
spam_check = await self.spam_checker.user_may_create_room_alias(
user_id, room_alias
):
raise AuthError(403, "This user is not permitted to create this alias")
)
if spam_check != self.spam_checker.NOT_SPAM:
raise AuthError(
403,
"This user is not permitted to create this alias",
spam_check,
)
if not self.config.roomdirectory.is_alias_creation_allowed(
user_id, room_id, room_alias_str
@ -430,9 +436,12 @@ class DirectoryHandler:
"""
user_id = requester.user.to_string()
if not await self.spam_checker.user_may_publish_room(user_id, room_id):
spam_check = await self.spam_checker.user_may_publish_room(user_id, room_id)
if spam_check != NOT_SPAM:
raise AuthError(
403, "This user is not permitted to publish rooms to the room list"
403,
"This user is not permitted to publish rooms to the room list",
spam_check,
)
if requester.is_guest:

10
synapse/handlers/federation.py
View File

@ -59,6 +59,7 @@ from synapse.federation.federation_client import InvalidResponseError
from synapse.http.servlet import assert_params_in_dict
from synapse.logging.context import nested_logging_context
from synapse.metrics.background_process_metrics import run_as_background_process
from synapse.module_api import NOT_SPAM
from synapse.replication.http.federation import (
ReplicationCleanRoomRestServlet,
ReplicationStoreRoomOnOutlierMembershipRestServlet,
@ -820,11 +821,14 @@ class FederationHandler:
if self.hs.config.server.block_non_admin_invites:
raise SynapseError(403, "This server does not accept room invites")
if not await self.spam_checker.user_may_invite(
spam_check = await self.spam_checker.user_may_invite(
event.sender, event.state_key, event.room_id
):
)
if spam_check != NOT_SPAM:
raise SynapseError(
403, "This user is not permitted to send invites to this server/user"
403,
"This user is not permitted to send invites to this server/user",
spam_check,
)
membership = event.content.get("membership")

12
synapse/handlers/message.py
View File

@ -954,14 +954,12 @@ class EventCreationHandler:
"Spam-check module returned invalid error value. Expecting [code, dict], got %s",
spam_check_result,
)
spam_check_result = Codes.FORBIDDEN
if isinstance(spam_check_result, Codes):
raise SynapseError(
403,
"This message has been rejected as probable spam",
spam_check_result,
)
raise SynapseError(
403,
"This message has been rejected as probable spam",
Codes.FORBIDDEN,
)
# Backwards compatibility: if the return value is not an error code, it
# means the module returned an error message to be included in the

20
synapse/handlers/room.py
View File

@ -62,6 +62,7 @@ from synapse.events.utils import copy_and_fixup_power_levels_contents
from synapse.federation.federation_client import InvalidResponseError
from synapse.handlers.federation import get_domains_from_state
from synapse.handlers.relations import BundledAggregations
from synapse.module_api import NOT_SPAM
from synapse.rest.admin._base import assert_user_is_admin
from synapse.storage.state import StateFilter
from synapse.streams import EventSource
@ -436,10 +437,9 @@ class RoomCreationHandler:
"""
user_id = requester.user.to_string()
if not await self.spam_checker.user_may_create_room(user_id):
raise SynapseError(
403, "You are not permitted to create rooms", Codes.FORBIDDEN
)
spam_check = await self.spam_checker.user_may_create_room(user_id)
if spam_check != NOT_SPAM:
raise SynapseError(403, "You are not permitted to create rooms", spam_check)
creation_content: JsonDict = {
"room_version": new_room_version.identifier,
@ -726,12 +726,12 @@ class RoomCreationHandler:
invite_3pid_list = config.get("invite_3pid", [])
invite_list = config.get("invite", [])
if not is_requester_admin and not (
await self.spam_checker.user_may_create_room(user_id)
):
raise SynapseError(
403, "You are not permitted to create rooms", Codes.FORBIDDEN
)
if not is_requester_admin:
spam_check = await self.spam_checker.user_may_create_room(user_id)
if spam_check != NOT_SPAM:
raise SynapseError(
403, "You are not permitted to create rooms", spam_check
)
if ratelimit:
await self.request_ratelimiter.ratelimit(requester)

32
synapse/handlers/room_member.py
View File

@ -38,6 +38,7 @@ from synapse.event_auth import get_named_level, get_power_level_event
from synapse.events import EventBase
from synapse.events.snapshot import EventContext
from synapse.handlers.profile import MAX_AVATAR_URL_LEN, MAX_DISPLAYNAME_LEN
from synapse.module_api import NOT_SPAM
from synapse.storage.state import StateFilter
from synapse.types import (
JsonDict,
@ -683,7 +684,7 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
if target_id == self._server_notices_mxid:
raise SynapseError(HTTPStatus.FORBIDDEN, "Cannot invite this user")
block_invite = False
block_invite_code = None
if (
self._server_notices_mxid is not None
@ -701,16 +702,19 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
"Blocking invite: user is not admin and non-admin "
"invites disabled"
)
block_invite = True
block_invite_code = Codes.FORBIDDEN
if not await self.spam_checker.user_may_invite(
spam_check = await self.spam_checker.user_may_invite(
requester.user.to_string(), target_id, room_id
):
)
if spam_check != NOT_SPAM:
logger.info("Blocking invite due to spam checker")
block_invite = True
block_invite_code = spam_check
if block_invite:
raise SynapseError(403, "Invites have been disabled on this server")
if block_invite_code is not None:
raise SynapseError(
403, "Invites have been disabled on this server", block_invite_code
)
# An empty prev_events list is allowed as long as the auth_event_ids are present
if prev_event_ids is not None:
@ -818,11 +822,12 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
# We assume that if the spam checker allowed the user to create
# a room then they're allowed to join it.
and not new_room
and not await self.spam_checker.user_may_join_room(
):
spam_check = await self.spam_checker.user_may_join_room(
target.to_string(), room_id, is_invited=inviter is not None
)
):
raise SynapseError(403, "Not allowed to join this room")
if spam_check != NOT_SPAM:
raise SynapseError(403, "Not allowed to join this room", spam_check)
# Check if a remote join should be performed.
remote_join, remote_room_hosts = await self._should_perform_remote_join(
@ -1369,13 +1374,14 @@ class RoomMemberHandler(metaclass=abc.ABCMeta):
)
else:
# Check if the spamchecker(s) allow this invite to go through.
if not await self.spam_checker.user_may_send_3pid_invite(
spam_check = await self.spam_checker.user_may_send_3pid_invite(
inviter_userid=requester.user.to_string(),
medium=medium,
address=address,
room_id=room_id,
):
raise SynapseError(403, "Cannot send threepid invite")
)
if spam_check != NOT_SPAM:
raise SynapseError(403, "Cannot send threepid invite", spam_check)
stream_id = await self._make_and_store_3pid_invite(
requester,

2
synapse/module_api/__init__.py
View File

@ -115,6 +115,7 @@ from synapse.types import (
JsonDict,
JsonMapping,
Requester,
RoomAlias,
StateMap,
UserID,
UserInfo,
@ -163,6 +164,7 @@ __all__ = [
"EventBase",
"StateMap",
"ProfileInfo",
"RoomAlias",
"UserProfile",
]

7
synapse/rest/media/v1/media_storage.py
View File

@ -36,6 +36,7 @@ from twisted.internet.defer import Deferred
from twisted.internet.interfaces import IConsumer
from twisted.protocols.basic import FileSender
import synapse
from synapse.api.errors import NotFoundError
from synapse.logging.context import defer_to_thread, make_deferred_yieldable
from synapse.util import Clock
@ -145,15 +146,15 @@ class MediaStorage:
f.flush()
f.close()
spam = await self.spam_checker.check_media_file_for_spam(
spam_check = await self.spam_checker.check_media_file_for_spam(
ReadableFileWrapper(self.clock, fname), file_info
)
if spam:
if spam_check != synapse.module_api.NOT_SPAM:
logger.info("Blocking media due to spam checker")
# Note that we'll delete the stored media, due to the
# try/except below. The media also won't be stored in
# the DB.
raise SpamMediaException()
raise SpamMediaException(errcode=spam_check)
for provider in self.storage_providers:
await provider.store_file(path, file_info)

175
tests/rest/client/test_rooms.py
View File

@ -18,10 +18,13 @@
"""Tests REST events for /rooms paths."""
import json
from typing import Any, Dict, Iterable, List, Optional
from typing import Any, Dict, Iterable, List, Optional, Union
from unittest.mock import Mock, call
from urllib import parse as urlparse
# `Literal` appears with Python 3.8.
from typing_extensions import Literal
from twisted.test.proto_helpers import MemoryReactor
import synapse.rest.admin
@ -777,9 +780,11 @@ class RoomsCreateTestCase(RoomBase):
channel = self.make_request("POST", "/createRoom", content)
self.assertEqual(200, channel.code)
def test_spam_checker_may_join_room(self) -> None:
def test_spam_checker_may_join_room_deprecated(self) -> None:
"""Tests that the user_may_join_room spam checker callback is correctly bypassed
when creating a new room.
In this test, we use the deprecated API in which callbacks return a bool.
"""
async def user_may_join_room(
@ -801,6 +806,32 @@ class RoomsCreateTestCase(RoomBase):
self.assertEqual(join_mock.call_count, 0)
def test_spam_checker_may_join_room(self) -> None:
"""Tests that the user_may_join_room spam checker callback is correctly bypassed
when creating a new room.
In this test, we use the more recent API in which callbacks return a `Union[Codes, Literal["NOT_SPAM"]]`.
"""
async def user_may_join_room(
mxid: str,
room_id: str,
is_invite: bool,
) -> Codes:
return Codes.CONSENT_NOT_GIVEN
join_mock = Mock(side_effect=user_may_join_room)
self.hs.get_spam_checker()._user_may_join_room_callbacks.append(join_mock)
channel = self.make_request(
"POST",
"/createRoom",
{},
)
self.assertEqual(channel.code, 200, channel.json_body)
self.assertEqual(join_mock.call_count, 0)
class RoomTopicTestCase(RoomBase):
"""Tests /rooms/$room_id/topic REST events."""
@ -1011,9 +1042,11 @@ class RoomJoinTestCase(RoomBase):
self.room2 = self.helper.create_room_as(room_creator=self.user1, tok=self.tok1)
self.room3 = self.helper.create_room_as(room_creator=self.user1, tok=self.tok1)
def test_spam_checker_may_join_room(self) -> None:
def test_spam_checker_may_join_room_deprecated(self) -> None:
"""Tests that the user_may_join_room spam checker callback is correctly called
and blocks room joins when needed.
This test uses the deprecated API, in which callbacks return booleans.
"""
# Register a dummy callback. Make it allow all room joins for now.
@ -1026,6 +1059,8 @@ class RoomJoinTestCase(RoomBase):
) -> bool:
return return_value
# `spec` argument is needed for this function mock to have `__qualname__`, which
# is needed for `Measure` metrics buried in SpamChecker.
callback_mock = Mock(side_effect=user_may_join_room, spec=lambda *x: None)
self.hs.get_spam_checker()._user_may_join_room_callbacks.append(callback_mock)
@ -1068,6 +1103,67 @@ class RoomJoinTestCase(RoomBase):
return_value = False
self.helper.join(self.room3, self.user2, expect_code=403, tok=self.tok2)
def test_spam_checker_may_join_room(self) -> None:
"""Tests that the user_may_join_room spam checker callback is correctly called
and blocks room joins when needed.
This test uses the latest API to this day, in which callbacks return `NOT_SPAM` or `Codes`.
"""
# Register a dummy callback. Make it allow all room joins for now.
return_value: Union[Literal["NOT_SPAM"], Codes] = synapse.module_api.NOT_SPAM
async def user_may_join_room(
userid: str,
room_id: str,
is_invited: bool,
) -> Union[Literal["NOT_SPAM"], Codes]:
return return_value
# `spec` argument is needed for this function mock to have `__qualname__`, which
# is needed for `Measure` metrics buried in SpamChecker.
callback_mock = Mock(side_effect=user_may_join_room, spec=lambda *x: None)
self.hs.get_spam_checker()._user_may_join_room_callbacks.append(callback_mock)
# Join a first room, without being invited to it.
self.helper.join(self.room1, self.user2, tok=self.tok2)
# Check that the callback was called with the right arguments.
expected_call_args = (
(
self.user2,
self.room1,
False,
),
)
self.assertEqual(
callback_mock.call_args,
expected_call_args,
callback_mock.call_args,
)
# Join a second room, this time with an invite for it.
self.helper.invite(self.room2, self.user1, self.user2, tok=self.tok1)
self.helper.join(self.room2, self.user2, tok=self.tok2)
# Check that the callback was called with the right arguments.
expected_call_args = (
(
self.user2,
self.room2,
True,
),
)
self.assertEqual(
callback_mock.call_args,
expected_call_args,
callback_mock.call_args,
)
# Now make the callback deny all room joins, and check that a join actually fails.
return_value = Codes.CONSENT_NOT_GIVEN
self.helper.join(self.room3, self.user2, expect_code=403, tok=self.tok2)
class RoomJoinRatelimitTestCase(RoomBase):
user_id = "@sid1:red"
@ -2945,9 +3041,14 @@ class ThreepidInviteTestCase(unittest.HomeserverTestCase):
self.room_id = self.helper.create_room_as(self.user_id, tok=self.tok)
def test_threepid_invite_spamcheck(self) -> None:
def test_threepid_invite_spamcheck_deprecated(self) -> None:
"""
Test allowing/blocking threepid invites with a spam-check module.
In this test, we use the deprecated API in which callbacks return a bool.
"""
# Mock a few functions to prevent the test from failing due to failing to talk to
# a remote IS. We keep the mock for _mock_make_and_store_3pid_invite around so we
# a remote IS. We keep the mock for make_and_store_3pid_invite around so we
# can check its call_count later on during the test.
make_invite_mock = Mock(return_value=make_awaitable(0))
self.hs.get_room_member_handler()._make_and_store_3pid_invite = make_invite_mock
@ -3001,3 +3102,67 @@ class ThreepidInviteTestCase(unittest.HomeserverTestCase):
# Also check that it stopped before calling _make_and_store_3pid_invite.
make_invite_mock.assert_called_once()
def test_threepid_invite_spamcheck(self) -> None:
"""
Test allowing/blocking threepid invites with a spam-check module.
In this test, we use the more recent API in which callbacks return a `Union[Codes, Literal["NOT_SPAM"]]`."""
# Mock a few functions to prevent the test from failing due to failing to talk to
# a remote IS. We keep the mock for make_and_store_3pid_invite around so we
# can check its call_count later on during the test.
make_invite_mock = Mock(return_value=make_awaitable(0))
self.hs.get_room_member_handler()._make_and_store_3pid_invite = make_invite_mock
self.hs.get_identity_handler().lookup_3pid = Mock(
return_value=make_awaitable(None),
)
# Add a mock to the spamchecker callbacks for user_may_send_3pid_invite. Make it
# allow everything for now.
# `spec` argument is needed for this function mock to have `__qualname__`, which
# is needed for `Measure` metrics buried in SpamChecker.
mock = Mock(
return_value=make_awaitable(synapse.module_api.NOT_SPAM),
spec=lambda *x: None,
)
self.hs.get_spam_checker()._user_may_send_3pid_invite_callbacks.append(mock)
# Send a 3PID invite into the room and check that it succeeded.
email_to_invite = "teresa@example.com"
channel = self.make_request(
method="POST",
path="/rooms/" + self.room_id + "/invite",
content={
"id_server": "example.com",
"id_access_token": "sometoken",
"medium": "email",
"address": email_to_invite,
},
access_token=self.tok,
)
self.assertEqual(channel.code, 200)
# Check that the callback was called with the right params.
mock.assert_called_with(self.user_id, "email", email_to_invite, self.room_id)
# Check that the call to send the invite was made.
make_invite_mock.assert_called_once()
# Now change the return value of the callback to deny any invite and test that
# we can't send the invite.
mock.return_value = make_awaitable(Codes.CONSENT_NOT_GIVEN)
channel = self.make_request(
method="POST",
path="/rooms/" + self.room_id + "/invite",
content={
"id_server": "example.com",
"id_access_token": "sometoken",
"medium": "email",
"address": email_to_invite,
},
access_token=self.tok,
)
self.assertEqual(channel.code, 403)
# Also check that it stopped before calling _make_and_store_3pid_invite.
make_invite_mock.assert_called_once()