mirror of
https://github.com/hoernschen/dendrite.git
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119 lines
3.7 KiB
Go
119 lines
3.7 KiB
Go
// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package auth
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import (
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"encoding/json"
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"fmt"
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"github.com/matrix-org/gomatrixserverlib"
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)
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const (
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shared = "shared"
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)
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// TODO: This logic should live in gomatrixserverlib
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// IsServerAllowed returns true if the server is allowed to see events in the room
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// at this particular state. This function implements https://matrix.org/docs/spec/client_server/r0.6.0#id87
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func IsServerAllowed(
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serverName gomatrixserverlib.ServerName,
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serverCurrentlyInRoom bool,
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authEvents []gomatrixserverlib.Event,
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) bool {
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var hisVisEvent *gomatrixserverlib.Event
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for i, ae := range authEvents {
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if ae.Type() == gomatrixserverlib.MRoomHistoryVisibility && ae.StateKeyEquals("") {
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hisVisEvent = &authEvents[i]
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break
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}
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}
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historyVisibility, err := HistoryVisibilityForRoom(hisVisEvent)
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if err != nil {
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return false
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}
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// 1. If the history_visibility was set to world_readable, allow.
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if historyVisibility == "world_readable" {
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return true
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}
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// 2. If the user's membership was join, allow.
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joinedUserExists := IsAnyUserOnServerWithMembership(serverName, authEvents, gomatrixserverlib.Join)
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if joinedUserExists {
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return true
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}
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// 3. If history_visibility was set to shared, and the user joined the room at any point after the event was sent, allow.
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if historyVisibility == shared && serverCurrentlyInRoom {
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return true
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}
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// 4. If the user's membership was invite, and the history_visibility was set to invited, allow.
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invitedUserExists := IsAnyUserOnServerWithMembership(serverName, authEvents, gomatrixserverlib.Invite)
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if invitedUserExists && historyVisibility == "invited" {
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return true
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}
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// 5. Otherwise, deny.
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return false
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}
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func HistoryVisibilityForRoom(hisVisEvent *gomatrixserverlib.Event) (string, error) {
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// https://matrix.org/docs/spec/client_server/r0.6.0#id87
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// By default if no history_visibility is set, or if the value is not understood, the visibility is assumed to be shared.
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if hisVisEvent == nil {
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return shared, nil
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}
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visibility := shared
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knownStates := []string{"invited", "joined", shared, "world_readable"}
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if hisVisEvent.Type() != gomatrixserverlib.MRoomHistoryVisibility {
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return "", fmt.Errorf("HistoryVisibilityForRoom: passed a non history visibility event: %s", hisVisEvent.Type())
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}
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// TODO: This should be HistoryVisibilityContent to match things like 'MemberContent'. Do this when moving to GMSL
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content := struct {
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HistoryVisibility string `json:"history_visibility"`
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}{}
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if err := json.Unmarshal(hisVisEvent.Content(), &content); err != nil {
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return visibility, nil // value is not understood
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}
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for _, s := range knownStates {
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if s == content.HistoryVisibility {
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visibility = s
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break
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}
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}
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return visibility, nil
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}
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func IsAnyUserOnServerWithMembership(serverName gomatrixserverlib.ServerName, authEvents []gomatrixserverlib.Event, wantMembership string) bool {
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for _, ev := range authEvents {
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membership, err := ev.Membership()
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if err != nil || membership != wantMembership {
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continue
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}
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stateKey := ev.StateKey()
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if stateKey == nil {
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continue
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}
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_, domain, err := gomatrixserverlib.SplitID('@', *stateKey)
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if err != nil {
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continue
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}
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if domain == serverName {
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return true
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}
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}
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return false
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}
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