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Commit 95a22ae1 authored by Erik Johnston's avatar Erik Johnston Committed by GitHub
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Merge pull request #1810 from matrix-org/erikj/state_auth_splitout_split 

Split out static auth methods from Auth object
parents f0325a9c e178feca
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synapse/api/auth.py
+ 8
− 571
View file @ 95a22ae1
......@@ -16,18 +16,14 @@
import logging
import pymacaroons
from canonicaljson import encode_canonical_json
from signedjson.key import decode_verify_key_bytes
from signedjson.sign import verify_signed_json, SignatureVerifyException
from twisted.internet import defer
from unpaddedbase64 import decode_base64
import synapse.types
from synapse import event_auth
from synapse.api.constants import EventTypes, Membership, JoinRules
from synapse.api.errors import AuthError, Codes, SynapseError, EventSizeError
from synapse.types import UserID, get_domain_from_id
from synapse.api.errors import AuthError, Codes
from synapse.types import UserID
from synapse.util.logcontext import preserve_context_over_fn
from synapse.util.logutils import log_function
from synapse.util.metrics import Measure
logger = logging.getLogger(__name__)
......@@ -78,147 +74,7 @@ class Auth(object):
True if the auth checks pass.
"""
with Measure(self.clock, "auth.check"):
self.check_size_limits(event)
if not hasattr(event, "room_id"):
raise AuthError(500, "Event has no room_id: %s" % event)
if do_sig_check:
sender_domain = get_domain_from_id(event.sender)
event_id_domain = get_domain_from_id(event.event_id)
is_invite_via_3pid = (
event.type == EventTypes.Member
and event.membership == Membership.INVITE
and "third_party_invite" in event.content
)
# Check the sender's domain has signed the event
if not event.signatures.get(sender_domain):
# We allow invites via 3pid to have a sender from a different
# HS, as the sender must match the sender of the original
# 3pid invite. This is checked further down with the
# other dedicated membership checks.
if not is_invite_via_3pid:
raise AuthError(403, "Event not signed by sender's server")
# Check the event_id's domain has signed the event
if not event.signatures.get(event_id_domain):
raise AuthError(403, "Event not signed by sending server")
if auth_events is None:
# Oh, we don't know what the state of the room was, so we
# are trusting that this is allowed (at least for now)
logger.warn("Trusting event: %s", event.event_id)
return True
if event.type == EventTypes.Create:
room_id_domain = get_domain_from_id(event.room_id)
if room_id_domain != sender_domain:
raise AuthError(
403,
"Creation event's room_id domain does not match sender's"
)
# FIXME
return True
creation_event = auth_events.get((EventTypes.Create, ""), None)
if not creation_event:
raise SynapseError(
403,
"Room %r does not exist" % (event.room_id,)
)
creating_domain = get_domain_from_id(event.room_id)
originating_domain = get_domain_from_id(event.sender)
if creating_domain != originating_domain:
if not self.can_federate(event, auth_events):
raise AuthError(
403,
"This room has been marked as unfederatable."
)
# FIXME: Temp hack
if event.type == EventTypes.Aliases:
if not event.is_state():
raise AuthError(
403,
"Alias event must be a state event",
)
if not event.state_key:
raise AuthError(
403,
"Alias event must have non-empty state_key"
)
sender_domain = get_domain_from_id(event.sender)
if event.state_key != sender_domain:
raise AuthError(
403,
"Alias event's state_key does not match sender's domain"
)
return True
logger.debug(
"Auth events: %s",
[a.event_id for a in auth_events.values()]
)
if event.type == EventTypes.Member:
allowed = self.is_membership_change_allowed(
event, auth_events
)
if allowed:
logger.debug("Allowing! %s", event)
else:
logger.debug("Denying! %s", event)
return allowed
self.check_event_sender_in_room(event, auth_events)
# Special case to allow m.room.third_party_invite events wherever
# a user is allowed to issue invites. Fixes
# https://github.com/vector-im/vector-web/issues/1208 hopefully
if event.type == EventTypes.ThirdPartyInvite:
user_level = self._get_user_power_level(event.user_id, auth_events)
invite_level = self._get_named_level(auth_events, "invite", 0)
if user_level < invite_level:
raise AuthError(
403, (
"You cannot issue a third party invite for %s." %
(event.content.display_name,)
)
)
else:
return True
self._can_send_event(event, auth_events)
if event.type == EventTypes.PowerLevels:
self._check_power_levels(event, auth_events)
if event.type == EventTypes.Redaction:
self.check_redaction(event, auth_events)
logger.debug("Allowing! %s", event)
def check_size_limits(self, event):
def too_big(field):
raise EventSizeError("%s too large" % (field,))
if len(event.user_id) > 255:
too_big("user_id")
if len(event.room_id) > 255:
too_big("room_id")
if event.is_state() and len(event.state_key) > 255:
too_big("state_key")
if len(event.type) > 255:
too_big("type")
if len(event.event_id) > 255:
too_big("event_id")
if len(encode_canonical_json(event.get_pdu_json())) > 65536:
too_big("event")
event_auth.check(event, auth_events, do_sig_check=do_sig_check)
@defer.inlineCallbacks
def check_joined_room(self, room_id, user_id, current_state=None):
......@@ -300,16 +156,6 @@ class Auth(object):
)
defer.returnValue(ret)
def check_event_sender_in_room(self, event, auth_events):
key = (EventTypes.Member, event.user_id, )
member_event = auth_events.get(key)
return self._check_joined_room(
member_event,
event.user_id,
event.room_id
)
def _check_joined_room(self, member, user_id, room_id):
if not member or member.membership != Membership.JOIN:
raise AuthError(403, "User %s not in room %s (%s)" % (
......@@ -321,267 +167,8 @@ class Auth(object):
return creation_event.content.get("m.federate", True) is True
@log_function
def is_membership_change_allowed(self, event, auth_events):
membership = event.content["membership"]
# Check if this is the room creator joining:
if len(event.prev_events) == 1 and Membership.JOIN == membership:
# Get room creation event:
key = (EventTypes.Create, "", )
create = auth_events.get(key)
if create and event.prev_events[0][0] == create.event_id:
if create.content["creator"] == event.state_key:
return True
target_user_id = event.state_key
creating_domain = get_domain_from_id(event.room_id)
target_domain = get_domain_from_id(target_user_id)
if creating_domain != target_domain:
if not self.can_federate(event, auth_events):
raise AuthError(
403,
"This room has been marked as unfederatable."
)
# get info about the caller
key = (EventTypes.Member, event.user_id, )
caller = auth_events.get(key)
caller_in_room = caller and caller.membership == Membership.JOIN
caller_invited = caller and caller.membership == Membership.INVITE
# get info about the target
key = (EventTypes.Member, target_user_id, )
target = auth_events.get(key)
target_in_room = target and target.membership == Membership.JOIN
target_banned = target and target.membership == Membership.BAN
key = (EventTypes.JoinRules, "", )
join_rule_event = auth_events.get(key)
if join_rule_event:
join_rule = join_rule_event.content.get(
"join_rule", JoinRules.INVITE
)
else:
join_rule = JoinRules.INVITE
user_level = self._get_user_power_level(event.user_id, auth_events)
target_level = self._get_user_power_level(
target_user_id, auth_events
)
# FIXME (erikj): What should we do here as the default?
ban_level = self._get_named_level(auth_events, "ban", 50)
logger.debug(
"is_membership_change_allowed: %s",
{
"caller_in_room": caller_in_room,
"caller_invited": caller_invited,
"target_banned": target_banned,
"target_in_room": target_in_room,
"membership": membership,
"join_rule": join_rule,
"target_user_id": target_user_id,
"event.user_id": event.user_id,
}
)
if Membership.INVITE == membership and "third_party_invite" in event.content:
if not self._verify_third_party_invite(event, auth_events):
raise AuthError(403, "You are not invited to this room.")
if target_banned:
raise AuthError(
403, "%s is banned from the room" % (target_user_id,)
)
return True
if Membership.JOIN != membership:
if (caller_invited
and Membership.LEAVE == membership
and target_user_id == event.user_id):
return True
if not caller_in_room: # caller isn't joined
raise AuthError(
403,
"%s not in room %s." % (event.user_id, event.room_id,)
)
if Membership.INVITE == membership:
# TODO (erikj): We should probably handle this more intelligently
# PRIVATE join rules.
# Invites are valid iff caller is in the room and target isn't.
if target_banned:
raise AuthError(
403, "%s is banned from the room" % (target_user_id,)
)
elif target_in_room: # the target is already in the room.
raise AuthError(403, "%s is already in the room." %
target_user_id)
else:
invite_level = self._get_named_level(auth_events, "invite", 0)
if user_level < invite_level:
raise AuthError(
403, "You cannot invite user %s." % target_user_id
)
elif Membership.JOIN == membership:
# Joins are valid iff caller == target and they were:
# invited: They are accepting the invitation
# joined: It's a NOOP
if event.user_id != target_user_id:
raise AuthError(403, "Cannot force another user to join.")
elif target_banned:
raise AuthError(403, "You are banned from this room")
elif join_rule == JoinRules.PUBLIC:
pass
elif join_rule == JoinRules.INVITE:
if not caller_in_room and not caller_invited:
raise AuthError(403, "You are not invited to this room.")
else:
# TODO (erikj): may_join list
# TODO (erikj): private rooms
raise AuthError(403, "You are not allowed to join this room")
elif Membership.LEAVE == membership:
# TODO (erikj): Implement kicks.
if target_banned and user_level < ban_level:
raise AuthError(
403, "You cannot unban user &s." % (target_user_id,)
)
elif target_user_id != event.user_id:
kick_level = self._get_named_level(auth_events, "kick", 50)
if user_level < kick_level or user_level <= target_level:
raise AuthError(
403, "You cannot kick user %s." % target_user_id
)
elif Membership.BAN == membership:
if user_level < ban_level or user_level <= target_level:
raise AuthError(403, "You don't have permission to ban")
else:
raise AuthError(500, "Unknown membership %s" % membership)
return True
def _verify_third_party_invite(self, event, auth_events):
"""
Validates that the invite event is authorized by a previous third-party invite.
Checks that the public key, and keyserver, match those in the third party invite,
and that the invite event has a signature issued using that public key.
Args:
event: The m.room.member join event being validated.
auth_events: All relevant previous context events which may be used
for authorization decisions.
Return:
True if the event fulfills the expectations of a previous third party
invite event.
"""
if "third_party_invite" not in event.content:
return False
if "signed" not in event.content["third_party_invite"]:
return False
signed = event.content["third_party_invite"]["signed"]
for key in {"mxid", "token"}:
if key not in signed:
return False
token = signed["token"]
invite_event = auth_events.get(
(EventTypes.ThirdPartyInvite, token,)
)
if not invite_event:
return False
if invite_event.sender != event.sender:
return False
if event.user_id != invite_event.user_id:
return False
if signed["mxid"] != event.state_key:
return False
if signed["token"] != token:
return False
for public_key_object in self.get_public_keys(invite_event):
public_key = public_key_object["public_key"]
try:
for server, signature_block in signed["signatures"].items():
for key_name, encoded_signature in signature_block.items():
if not key_name.startswith("ed25519:"):
continue
verify_key = decode_verify_key_bytes(
key_name,
decode_base64(public_key)
)
verify_signed_json(signed, server, verify_key)
# We got the public key from the invite, so we know that the
# correct server signed the signed bundle.
# The caller is responsible for checking that the signing
# server has not revoked that public key.
return True
except (KeyError, SignatureVerifyException,):
continue
return False
def get_public_keys(self, invite_event):
public_keys = []
if "public_key" in invite_event.content:
o = {
"public_key": invite_event.content["public_key"],
}
if "key_validity_url" in invite_event.content:
o["key_validity_url"] = invite_event.content["key_validity_url"]
public_keys.append(o)
public_keys.extend(invite_event.content.get("public_keys", []))
return public_keys
def _get_power_level_event(self, auth_events):
key = (EventTypes.PowerLevels, "", )
return auth_events.get(key)
def _get_user_power_level(self, user_id, auth_events):
power_level_event = self._get_power_level_event(auth_events)
if power_level_event:
level = power_level_event.content.get("users", {}).get(user_id)
if not level:
level = power_level_event.content.get("users_default", 0)
if level is None:
return 0
else:
return int(level)
else:
key = (EventTypes.Create, "", )
create_event = auth_events.get(key)
if (create_event is not None and
create_event.content["creator"] == user_id):
return 100
else:
return 0
def _get_named_level(self, auth_events, name, default):
power_level_event = self._get_power_level_event(auth_events)
if not power_level_event:
return default
level = power_level_event.content.get(name, None)
if level is not None:
return int(level)
else:
return default
return event_auth.get_public_keys(invite_event)
@defer.inlineCallbacks
def get_user_by_req(self, request, allow_guest=False, rights="access"):
......@@ -974,56 +561,6 @@ class Auth(object):
defer.returnValue(auth_ids)
def _get_send_level(self, etype, state_key, auth_events):
key = (EventTypes.PowerLevels, "", )
send_level_event = auth_events.get(key)
send_level = None
if send_level_event:
send_level = send_level_event.content.get("events", {}).get(
etype
)
if send_level is None:
if state_key is not None:
send_level = send_level_event.content.get(
"state_default", 50
)
else:
send_level = send_level_event.content.get(
"events_default", 0
)
if send_level:
send_level = int(send_level)
else:
send_level = 0
return send_level
@log_function
def _can_send_event(self, event, auth_events):
send_level = self._get_send_level(
event.type, event.get("state_key", None), auth_events
)
user_level = self._get_user_power_level(event.user_id, auth_events)
if user_level < send_level:
raise AuthError(
403,
"You don't have permission to post that to the room. " +
"user_level (%d) < send_level (%d)" % (user_level, send_level)
)
# Check state_key
if hasattr(event, "state_key"):
if event.state_key.startswith("@"):
if event.state_key != event.user_id:
raise AuthError(
403,
"You are not allowed to set others state"
)
return True
def check_redaction(self, event, auth_events):
"""Check whether the event sender is allowed to redact the target event.
......@@ -1037,107 +574,7 @@ class Auth(object):
AuthError if the event sender is definitely not allowed to redact
the target event.
"""
user_level = self._get_user_power_level(event.user_id, auth_events)
redact_level = self._get_named_level(auth_events, "redact", 50)
if user_level >= redact_level:
return False
redacter_domain = get_domain_from_id(event.event_id)
redactee_domain = get_domain_from_id(event.redacts)
if redacter_domain == redactee_domain:
return True
raise AuthError(
403,
"You don't have permission to redact events"
)
def _check_power_levels(self, event, auth_events):
user_list = event.content.get("users", {})
# Validate users
for k, v in user_list.items():
try:
UserID.from_string(k)
except:
raise SynapseError(400, "Not a valid user_id: %s" % (k,))
try:
int(v)
except:
raise SynapseError(400, "Not a valid power level: %s" % (v,))
key = (event.type, event.state_key, )
current_state = auth_events.get(key)
if not current_state:
return
user_level = self._get_user_power_level(event.user_id, auth_events)
# Check other levels:
levels_to_check = [
("users_default", None),
("events_default", None),
("state_default", None),
("ban", None),
("redact", None),
("kick", None),
("invite", None),
]
old_list = current_state.content.get("users")
for user in set(old_list.keys() + user_list.keys()):
levels_to_check.append(
(user, "users")
)
old_list = current_state.content.get("events")
new_list = event.content.get("events")
for ev_id in set(old_list.keys() + new_list.keys()):
levels_to_check.append(
(ev_id, "events")
)
old_state = current_state.content
new_state = event.content
for level_to_check, dir in levels_to_check:
old_loc = old_state
new_loc = new_state
if dir:
old_loc = old_loc.get(dir, {})
new_loc = new_loc.get(dir, {})
if level_to_check in old_loc:
old_level = int(old_loc[level_to_check])
else:
old_level = None
if level_to_check in new_loc:
new_level = int(new_loc[level_to_check])
else:
new_level = None
if new_level is not None and old_level is not None:
if new_level == old_level:
continue
if dir == "users" and level_to_check != event.user_id:
if old_level == user_level:
raise AuthError(
403,
"You don't have permission to remove ops level equal "
"to your own"
)
if old_level > user_level or new_level > user_level:
raise AuthError(
403,
"You don't have permission to add ops level greater "
"than your own"
)
return event_auth.check_redaction(event, auth_events)
@defer.inlineCallbacks
def check_can_change_room_list(self, room_id, user):
......@@ -1167,10 +604,10 @@ class Auth(object):
if power_level_event:
auth_events[(EventTypes.PowerLevels, "")] = power_level_event
send_level = self._get_send_level(
send_level = event_auth.get_send_level(
EventTypes.Aliases, "", auth_events
)
user_level = self._get_user_power_level(user_id, auth_events)
user_level = event_auth.get_user_power_level(user_id, auth_events)
if user_level < send_level:
raise AuthError(
......
synapse/event_auth.py 0 → 100644
+ 641
− 0
View file @ 95a22ae1
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