265 lines
11 KiB
Go
265 lines
11 KiB
Go
|
// Copyright (c) 2020 Nikos Filippakis
|
||
|
|
//
|
||
|
|
// This Source Code Form is subject to the terms of the Mozilla Public
|
||
|
|
// License, v. 2.0. If a copy of the MPL was not distributed with this
|
||
|
|
// file, You can obtain one at http://mozilla.org/MPL/2.0/.
|
||
|
|
|
||
|
|
//go:build !nosas
|
||
|
|
// +build !nosas
|
||
|
|
|
||
|
|
package crypto
|
||
|
|
|
||
|
|
import (
|
||
|
|
"context"
|
||
|
|
|
||
|
|
"maunium.net/go/mautrix/crypto/olm"
|
||
|
|
"maunium.net/go/mautrix/id"
|
||
|
|
|
||
|
|
"maunium.net/go/mautrix"
|
||
|
|
"maunium.net/go/mautrix/event"
|
||
|
|
)
|
||
|
|
|
||
|
|
type KeyShareRejection struct {
|
||
|
|
Code event.RoomKeyWithheldCode
|
||
|
|
Reason string
|
||
|
|
}
|
||
|
|
|
||
|
|
var (
|
||
|
|
// Reject a key request without responding
|
||
|
|
KeyShareRejectNoResponse = KeyShareRejection{}
|
||
|
|
|
||
|
|
KeyShareRejectBlacklisted = KeyShareRejection{event.RoomKeyWithheldBlacklisted, "You have been blacklisted by this device"}
|
||
|
|
KeyShareRejectUnverified = KeyShareRejection{event.RoomKeyWithheldUnverified, "This device does not share keys to unverified devices"}
|
||
|
|
KeyShareRejectOtherUser = KeyShareRejection{event.RoomKeyWithheldUnauthorized, "This device does not share keys to other users"}
|
||
|
|
KeyShareRejectUnavailable = KeyShareRejection{event.RoomKeyWithheldUnavailable, "Requested session ID not found on this device"}
|
||
|
|
KeyShareRejectInternalError = KeyShareRejection{event.RoomKeyWithheldUnavailable, "An internal error occurred while trying to share the requested session"}
|
||
|
|
)
|
||
|
|
|
||
|
|
// RequestRoomKey sends a key request for a room to the current user's devices. If the context is cancelled, then so is the key request.
|
||
|
|
// Returns a bool channel that will get notified either when the key is received or the request is cancelled.
|
||
|
|
//
|
||
|
|
// Deprecated: this only supports a single key request target, so the whole automatic cancelling feature isn't very useful.
|
||
|
|
func (mach *OlmMachine) RequestRoomKey(ctx context.Context, toUser id.UserID, toDevice id.DeviceID,
|
||
|
|
roomID id.RoomID, senderKey id.SenderKey, sessionID id.SessionID) (chan bool, error) {
|
||
|
|
|
||
|
|
requestID := mach.Client.TxnID()
|
||
|
|
keyResponseReceived := make(chan struct{})
|
||
|
|
mach.roomKeyRequestFilled.Store(sessionID, keyResponseReceived)
|
||
|
|
|
||
|
|
err := mach.SendRoomKeyRequest(roomID, senderKey, sessionID, requestID, map[id.UserID][]id.DeviceID{toUser: {toDevice}})
|
||
|
|
if err != nil {
|
||
|
|
return nil, err
|
||
|
|
}
|
||
|
|
|
||
|
|
resChan := make(chan bool, 1)
|
||
|
|
go func() {
|
||
|
|
select {
|
||
|
|
case <-keyResponseReceived:
|
||
|
|
// key request successful
|
||
|
|
mach.Log.Debug("Key for session %v was received, cancelling other key requests", sessionID)
|
||
|
|
resChan <- true
|
||
|
|
case <-ctx.Done():
|
||
|
|
// if the context is done, key request was unsuccessful
|
||
|
|
mach.Log.Debug("Context closed (%v) before forwared key for session %v received, sending key request cancellation", ctx.Err(), sessionID)
|
||
|
|
resChan <- false
|
||
|
|
}
|
||
|
|
|
||
|
|
// send a message to all devices cancelling this key request
|
||
|
|
mach.roomKeyRequestFilled.Delete(sessionID)
|
||
|
|
|
||
|
|
cancelEvtContent := &event.Content{
|
||
|
|
Parsed: event.RoomKeyRequestEventContent{
|
||
|
|
Action: event.KeyRequestActionCancel,
|
||
|
|
RequestID: requestID,
|
||
|
|
RequestingDeviceID: mach.Client.DeviceID,
|
||
|
|
},
|
||
|
|
}
|
||
|
|
|
||
|
|
toDeviceCancel := &mautrix.ReqSendToDevice{
|
||
|
|
Messages: map[id.UserID]map[id.DeviceID]*event.Content{
|
||
|
|
toUser: {
|
||
|
|
toDevice: cancelEvtContent,
|
||
|
|
},
|
||
|
|
},
|
||
|
|
}
|
||
|
|
|
||
|
|
mach.Client.SendToDevice(event.ToDeviceRoomKeyRequest, toDeviceCancel)
|
||
|
|
}()
|
||
|
|
return resChan, nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// SendRoomKeyRequest sends a key request for the given key (identified by the room ID, sender key and session ID) to the given users.
|
||
|
|
//
|
||
|
|
// The request ID parameter is optional. If it's empty, a random ID will be generated.
|
||
|
|
//
|
||
|
|
// This function does not wait for the keys to arrive. You can use WaitForSession to wait for the session to
|
||
|
|
// arrive (in any way, not just as a reply to this request). There's also RequestRoomKey which waits for a response
|
||
|
|
// to the specific key request, but currently it only supports a single target device and is therefore deprecated.
|
||
|
|
// A future function may properly support multiple targets and automatically canceling the other requests when receiving
|
||
|
|
// the first response.
|
||
|
|
func (mach *OlmMachine) SendRoomKeyRequest(roomID id.RoomID, senderKey id.SenderKey, sessionID id.SessionID, requestID string, users map[id.UserID][]id.DeviceID) error {
|
||
|
|
if len(requestID) == 0 {
|
||
|
|
requestID = mach.Client.TxnID()
|
||
|
|
}
|
||
|
|
requestEvent := &event.Content{
|
||
|
|
Parsed: &event.RoomKeyRequestEventContent{
|
||
|
|
Action: event.KeyRequestActionRequest,
|
||
|
|
Body: event.RequestedKeyInfo{
|
||
|
|
Algorithm: id.AlgorithmMegolmV1,
|
||
|
|
RoomID: roomID,
|
||
|
|
SenderKey: senderKey,
|
||
|
|
SessionID: sessionID,
|
||
|
|
},
|
||
|
|
RequestID: requestID,
|
||
|
|
RequestingDeviceID: mach.Client.DeviceID,
|
||
|
|
},
|
||
|
|
}
|
||
|
|
|
||
|
|
toDeviceReq := &mautrix.ReqSendToDevice{
|
||
|
|
Messages: make(map[id.UserID]map[id.DeviceID]*event.Content, len(users)),
|
||
|
|
}
|
||
|
|
for user, devices := range users {
|
||
|
|
toDeviceReq.Messages[user] = make(map[id.DeviceID]*event.Content, len(devices))
|
||
|
|
for _, device := range devices {
|
||
|
|
toDeviceReq.Messages[user][device] = requestEvent
|
||
|
|
}
|
||
|
|
}
|
||
|
|
_, err := mach.Client.SendToDevice(event.ToDeviceRoomKeyRequest, toDeviceReq)
|
||
|
|
return err
|
||
|
|
}
|
||
|
|
|
||
|
|
func (mach *OlmMachine) importForwardedRoomKey(evt *DecryptedOlmEvent, content *event.ForwardedRoomKeyEventContent) bool {
|
||
|
|
if content.Algorithm != id.AlgorithmMegolmV1 || evt.Keys.Ed25519 == "" {
|
||
|
|
mach.Log.Debug("Ignoring weird forwarded room key from %s/%s: alg=%s, ed25519=%s, sessionid=%s, roomid=%s", evt.Sender, evt.SenderDevice, content.Algorithm, evt.Keys.Ed25519, content.SessionID, content.RoomID)
|
||
|
|
return false
|
||
|
|
}
|
||
|
|
|
||
|
|
igsInternal, err := olm.InboundGroupSessionImport([]byte(content.SessionKey))
|
||
|
|
if err != nil {
|
||
|
|
mach.Log.Error("Failed to import inbound group session: %v", err)
|
||
|
|
return false
|
||
|
|
} else if igsInternal.ID() != content.SessionID {
|
||
|
|
mach.Log.Warn("Mismatched session ID while creating inbound group session")
|
||
|
|
return false
|
||
|
|
}
|
||
|
|
igs := &InboundGroupSession{
|
||
|
|
Internal: *igsInternal,
|
||
|
|
SigningKey: evt.Keys.Ed25519,
|
||
|
|
SenderKey: content.SenderKey,
|
||
|
|
RoomID: content.RoomID,
|
||
|
|
ForwardingChains: append(content.ForwardingKeyChain, evt.SenderKey.String()),
|
||
|
|
id: content.SessionID,
|
||
|
|
}
|
||
|
|
err = mach.CryptoStore.PutGroupSession(content.RoomID, content.SenderKey, content.SessionID, igs)
|
||
|
|
if err != nil {
|
||
|
|
mach.Log.Error("Failed to store new inbound group session: %v", err)
|
||
|
|
return false
|
||
|
|
}
|
||
|
|
mach.markSessionReceived(content.SessionID)
|
||
|
|
mach.Log.Trace("Received forwarded inbound group session %s/%s/%s", content.RoomID, content.SenderKey, content.SessionID)
|
||
|
|
return true
|
||
|
|
}
|
||
|
|
|
||
|
|
func (mach *OlmMachine) rejectKeyRequest(rejection KeyShareRejection, device *id.Device, request event.RequestedKeyInfo) {
|
||
|
|
if rejection.Code == "" {
|
||
|
|
// If the rejection code is empty, it means don't share keys, but also don't tell the requester.
|
||
|
|
return
|
||
|
|
}
|
||
|
|
content := event.RoomKeyWithheldEventContent{
|
||
|
|
RoomID: request.RoomID,
|
||
|
|
Algorithm: request.Algorithm,
|
||
|
|
SessionID: request.SessionID,
|
||
|
|
SenderKey: request.SenderKey,
|
||
|
|
Code: rejection.Code,
|
||
|
|
Reason: rejection.Reason,
|
||
|
|
}
|
||
|
|
err := mach.sendToOneDevice(device.UserID, device.DeviceID, event.ToDeviceRoomKeyWithheld, &content)
|
||
|
|
if err != nil {
|
||
|
|
mach.Log.Warn("Failed to send key share rejection %s to %s/%s: %v", rejection.Code, device.UserID, device.DeviceID, err)
|
||
|
|
}
|
||
|
|
err = mach.sendToOneDevice(device.UserID, device.DeviceID, event.ToDeviceOrgMatrixRoomKeyWithheld, &content)
|
||
|
|
if err != nil {
|
||
|
|
mach.Log.Warn("Failed to send key share rejection %s (org.matrix.) to %s/%s: %v", rejection.Code, device.UserID, device.DeviceID, err)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
func (mach *OlmMachine) defaultAllowKeyShare(device *id.Device, _ event.RequestedKeyInfo) *KeyShareRejection {
|
||
|
|
if mach.Client.UserID != device.UserID {
|
||
|
|
mach.Log.Debug("Ignoring key request from a different user (%s)", device.UserID)
|
||
|
|
return &KeyShareRejectOtherUser
|
||
|
|
} else if mach.Client.DeviceID == device.DeviceID {
|
||
|
|
mach.Log.Debug("Ignoring key request from ourselves")
|
||
|
|
return &KeyShareRejectNoResponse
|
||
|
|
} else if device.Trust == id.TrustStateBlacklisted {
|
||
|
|
mach.Log.Debug("Ignoring key request from blacklisted device %s", device.DeviceID)
|
||
|
|
return &KeyShareRejectBlacklisted
|
||
|
|
} else if trustState := mach.ResolveTrust(device); trustState >= mach.ShareKeysMinTrust {
|
||
|
|
mach.Log.Debug("Accepting key request from device %s (trust state: %s)", device.DeviceID, trustState)
|
||
|
|
return nil
|
||
|
|
} else {
|
||
|
|
mach.Log.Debug("Ignoring key request from unverified device %s (trust state: %s)", device.DeviceID, trustState)
|
||
|
|
return &KeyShareRejectUnverified
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
func (mach *OlmMachine) handleRoomKeyRequest(sender id.UserID, content *event.RoomKeyRequestEventContent) {
|
||
|
|
if content.Action != event.KeyRequestActionRequest {
|
||
|
|
return
|
||
|
|
} else if content.RequestingDeviceID == mach.Client.DeviceID && sender == mach.Client.UserID {
|
||
|
|
mach.Log.Debug("Ignoring key request %s from ourselves", content.RequestID)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
mach.Log.Debug("Received key request %s for %s from %s/%s", content.RequestID, content.Body.SessionID, sender, content.RequestingDeviceID)
|
||
|
|
|
||
|
|
device, err := mach.GetOrFetchDevice(sender, content.RequestingDeviceID)
|
||
|
|
if err != nil {
|
||
|
|
mach.Log.Error("Failed to fetch device %s/%s that requested keys: %v", sender, content.RequestingDeviceID, err)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
rejection := mach.AllowKeyShare(device, content.Body)
|
||
|
|
if rejection != nil {
|
||
|
|
mach.rejectKeyRequest(*rejection, device, content.Body)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
igs, err := mach.CryptoStore.GetGroupSession(content.Body.RoomID, content.Body.SenderKey, content.Body.SessionID)
|
||
|
|
if err != nil {
|
||
|
|
mach.Log.Error("Failed to fetch group session to forward to %s/%s: %v", device.UserID, device.DeviceID, err)
|
||
|
|
mach.rejectKeyRequest(KeyShareRejectInternalError, device, content.Body)
|
||
|
|
return
|
||
|
|
} else if igs == nil {
|
||
|
|
mach.Log.Warn("Didn't find group session %s to forward to %s/%s", content.Body.SessionID, device.UserID, device.DeviceID)
|
||
|
|
mach.rejectKeyRequest(KeyShareRejectUnavailable, device, content.Body)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
exportedKey, err := igs.Internal.Export(igs.Internal.FirstKnownIndex())
|
||
|
|
if err != nil {
|
||
|
|
mach.Log.Error("Failed to export session %s to forward to %s/%s: %v", igs.ID(), device.UserID, device.DeviceID, err)
|
||
|
|
mach.rejectKeyRequest(KeyShareRejectInternalError, device, content.Body)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
forwardedRoomKey := event.Content{
|
||
|
|
Parsed: &event.ForwardedRoomKeyEventContent{
|
||
|
|
RoomKeyEventContent: event.RoomKeyEventContent{
|
||
|
|
Algorithm: id.AlgorithmMegolmV1,
|
||
|
|
RoomID: igs.RoomID,
|
||
|
|
SessionID: igs.ID(),
|
||
|
|
SessionKey: exportedKey,
|
||
|
|
},
|
||
|
|
SenderKey: content.Body.SenderKey,
|
||
|
|
ForwardingKeyChain: igs.ForwardingChains,
|
||
|
|
SenderClaimedKey: igs.SigningKey,
|
||
|
|
},
|
||
|
|
}
|
||
|
|
|
||
|
|
if err := mach.SendEncryptedToDevice(device, event.ToDeviceForwardedRoomKey, forwardedRoomKey); err != nil {
|
||
|
|
mach.Log.Error("Failed to send encrypted forwarded key %s to %s/%s: %v", igs.ID(), device.UserID, device.DeviceID, err)
|
||
|
|
}
|
||
|
|
|
||
|
|
mach.Log.Debug("Sent encrypted forwarded key to device %s/%s for session %s", device.UserID, device.DeviceID, igs.ID())
|
||
|
|
}
|