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// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// 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.
package auth
import (
"context"
"github.com/matrix-org/dendrite/roomserver/api"
"github.com/matrix-org/gomatrixserverlib"
"github.com/matrix-org/gomatrixserverlib/spec"
)
// TODO: This logic should live in gomatrixserverlib
// IsServerAllowed returns true if the server is allowed to see events in the room
// at this particular state. This function implements https://matrix.org/docs/spec/client_server/r0.6.0#id87
func IsServerAllowed(
ctx context.Context, querier api.QuerySenderIDAPI,
serverName spec.ServerName,
serverCurrentlyInRoom bool,
authEvents []gomatrixserverlib.PDU,
) bool {
historyVisibility := HistoryVisibilityForRoom(authEvents)
// 1. If the history_visibility was set to world_readable, allow.
if historyVisibility == gomatrixserverlib.HistoryVisibilityWorldReadable {
return true
}
// 2. If the user's membership was join, allow.
joinedUserExists := IsAnyUserOnServerWithMembership(ctx, querier, serverName, authEvents, spec.Join)
if joinedUserExists {
return true
}
// 3. If history_visibility was set to shared, and the user joined the room at any point after the event was sent, allow.
if historyVisibility == gomatrixserverlib.HistoryVisibilityShared && serverCurrentlyInRoom {
return true
}
// 4. If the user's membership was invite, and the history_visibility was set to invited, allow.
invitedUserExists := IsAnyUserOnServerWithMembership(ctx, querier, serverName, authEvents, spec.Invite)
if invitedUserExists && historyVisibility == gomatrixserverlib.HistoryVisibilityInvited {
return true
}
// 5. Otherwise, deny.
return false
}
func HistoryVisibilityForRoom(authEvents []gomatrixserverlib.PDU) gomatrixserverlib.HistoryVisibility {
// https://matrix.org/docs/spec/client_server/r0.6.0#id87
// By default if no history_visibility is set, or if the value is not understood, the visibility is assumed to be shared.
visibility := gomatrixserverlib.HistoryVisibilityShared
for _, ev := range authEvents {
if ev.Type() != spec.MRoomHistoryVisibility {
continue
}
if vis, err := ev.HistoryVisibility(); err == nil {
visibility = vis
}
}
return visibility
}
func IsAnyUserOnServerWithMembership(ctx context.Context, querier api.QuerySenderIDAPI, serverName spec.ServerName, authEvents []gomatrixserverlib.PDU, wantMembership string) bool {
for _, ev := range authEvents {
if ev.Type() != spec.MRoomMember {
continue
}
membership, err := ev.Membership()
if err != nil || membership != wantMembership {
continue
}
stateKey := ev.StateKey()
if stateKey == nil {
continue
}
userID, err := querier.QueryUserIDForSender(ctx, ev.RoomID(), spec.SenderID(*stateKey))
if err != nil {
continue
}
if userID.Domain() == serverName {
return true
}
}
return false
}
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