summary refs log tree commit diff
path: root/src/Olm.cpp
blob: af8bb512e6a5101fd69d8776f166c19880fea39d (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
#include "Olm.h"

#include <QObject>
#include <nlohmann/json.hpp>
#include <variant>

#include "Cache.h"
#include "Cache_p.h"
#include "ChatPage.h"
#include "DeviceVerificationFlow.h"
#include "Logging.h"
#include "MatrixClient.h"
#include "UserSettingsPage.h"
#include "Utils.h"

static const std::string STORAGE_SECRET_KEY("secret");
constexpr auto MEGOLM_ALGO = "m.megolm.v1.aes-sha2";

namespace {
auto client_ = std::make_unique<mtx::crypto::OlmClient>();
}

namespace olm {
void
from_json(const nlohmann::json &obj, OlmMessage &msg)
{
        if (obj.at("type") != "m.room.encrypted")
                throw std::invalid_argument("invalid type for olm message");

        if (obj.at("content").at("algorithm") != OLM_ALGO)
                throw std::invalid_argument("invalid algorithm for olm message");

        msg.sender     = obj.at("sender");
        msg.sender_key = obj.at("content").at("sender_key");
        msg.ciphertext = obj.at("content")
                           .at("ciphertext")
                           .get<std::map<std::string, mtx::events::msg::OlmCipherContent>>();
}

mtx::crypto::OlmClient *
client()
{
        return client_.get();
}

void
handle_to_device_messages(const std::vector<mtx::events::collections::DeviceEvents> &msgs)
{
        if (msgs.empty())
                return;
        nhlog::crypto()->info("received {} to_device messages", msgs.size());
        nlohmann::json j_msg;

        for (const auto &msg : msgs) {
                j_msg = std::visit([](auto &e) { return json(e); }, std::move(msg));
                if (j_msg.count("type") == 0) {
                        nhlog::crypto()->warn("received message with no type field: {}",
                                              j_msg.dump(2));
                        continue;
                }

                std::string msg_type = j_msg.at("type");

                if (msg_type == to_string(mtx::events::EventType::RoomEncrypted)) {
                        try {
                                olm::OlmMessage olm_msg = j_msg;
                                handle_olm_message(std::move(olm_msg));
                        } catch (const nlohmann::json::exception &e) {
                                nhlog::crypto()->warn(
                                  "parsing error for olm message: {} {}", e.what(), j_msg.dump(2));
                        } catch (const std::invalid_argument &e) {
                                nhlog::crypto()->warn("validation error for olm message: {} {}",
                                                      e.what(),
                                                      j_msg.dump(2));
                        }

                } else if (msg_type == to_string(mtx::events::EventType::RoomKeyRequest)) {
                        nhlog::crypto()->warn("handling key request event: {}", j_msg.dump(2));
                        try {
                                mtx::events::DeviceEvent<mtx::events::msg::KeyRequest> req = j_msg;
                                if (req.content.action == mtx::events::msg::RequestAction::Request)
                                        handle_key_request_message(req);
                                else
                                        nhlog::crypto()->warn(
                                          "ignore key request (unhandled action): {}",
                                          req.content.request_id);
                        } catch (const nlohmann::json::exception &e) {
                                nhlog::crypto()->warn(
                                  "parsing error for key_request message: {} {}",
                                  e.what(),
                                  j_msg.dump(2));
                        }
                } else if (msg_type == to_string(mtx::events::EventType::KeyVerificationAccept)) {
                        auto message = std::get<
                          mtx::events::DeviceEvent<mtx::events::msg::KeyVerificationAccept>>(msg);
                        ChatPage::instance()->receivedDeviceVerificationAccept(message.content);
                } else if (msg_type == to_string(mtx::events::EventType::KeyVerificationRequest)) {
                        auto message = std::get<
                          mtx::events::DeviceEvent<mtx::events::msg::KeyVerificationRequest>>(msg);
                        ChatPage::instance()->receivedDeviceVerificationRequest(message.content,
                                                                                message.sender);
                } else if (msg_type == to_string(mtx::events::EventType::KeyVerificationCancel)) {
                        auto message = std::get<
                          mtx::events::DeviceEvent<mtx::events::msg::KeyVerificationCancel>>(msg);
                        ChatPage::instance()->receivedDeviceVerificationCancel(message.content);
                } else if (msg_type == to_string(mtx::events::EventType::KeyVerificationKey)) {
                        auto message =
                          std::get<mtx::events::DeviceEvent<mtx::events::msg::KeyVerificationKey>>(
                            msg);
                        ChatPage::instance()->receivedDeviceVerificationKey(message.content);
                } else if (msg_type == to_string(mtx::events::EventType::KeyVerificationMac)) {
                        auto message =
                          std::get<mtx::events::DeviceEvent<mtx::events::msg::KeyVerificationMac>>(
                            msg);
                        ChatPage::instance()->receivedDeviceVerificationMac(message.content);
                } else if (msg_type == to_string(mtx::events::EventType::KeyVerificationStart)) {
                        auto message = std::get<
                          mtx::events::DeviceEvent<mtx::events::msg::KeyVerificationStart>>(msg);
                        ChatPage::instance()->receivedDeviceVerificationStart(message.content,
                                                                              message.sender);
                } else if (msg_type == to_string(mtx::events::EventType::KeyVerificationReady)) {
                        auto message = std::get<
                          mtx::events::DeviceEvent<mtx::events::msg::KeyVerificationReady>>(msg);
                        ChatPage::instance()->receivedDeviceVerificationReady(message.content);
                } else if (msg_type == to_string(mtx::events::EventType::KeyVerificationDone)) {
                        auto message =
                          std::get<mtx::events::DeviceEvent<mtx::events::msg::KeyVerificationDone>>(
                            msg);
                        ChatPage::instance()->receivedDeviceVerificationDone(message.content);
                } else {
                        nhlog::crypto()->warn("unhandled event: {}", j_msg.dump(2));
                }
        }
}

void
handle_olm_message(const OlmMessage &msg)
{
        nhlog::crypto()->info("sender    : {}", msg.sender);
        nhlog::crypto()->info("sender_key: {}", msg.sender_key);

        const auto my_key = olm::client()->identity_keys().curve25519;

        for (const auto &cipher : msg.ciphertext) {
                // We skip messages not meant for the current device.
                if (cipher.first != my_key)
                        continue;

                const auto type = cipher.second.type;
                nhlog::crypto()->info("type: {}", type == 0 ? "OLM_PRE_KEY" : "OLM_MESSAGE");

                auto payload = try_olm_decryption(msg.sender_key, cipher.second);

                if (payload.is_null()) {
                        // Check for PRE_KEY message
                        if (cipher.second.type == 0) {
                                payload = handle_pre_key_olm_message(
                                  msg.sender, msg.sender_key, cipher.second);
                        } else {
                                nhlog::crypto()->error("Undecryptable olm message!");
                                continue;
                        }
                }

                if (!payload.is_null()) {
                        std::string msg_type = payload["type"];

                        if (msg_type == to_string(mtx::events::EventType::KeyVerificationAccept)) {
                                ChatPage::instance()->receivedDeviceVerificationAccept(
                                  payload["content"]);
                                return;
                        } else if (msg_type ==
                                   to_string(mtx::events::EventType::KeyVerificationRequest)) {
                                ChatPage::instance()->receivedDeviceVerificationRequest(
                                  payload["content"], payload["sender"]);
                                return;
                        } else if (msg_type ==
                                   to_string(mtx::events::EventType::KeyVerificationCancel)) {
                                ChatPage::instance()->receivedDeviceVerificationCancel(
                                  payload["content"]);
                                return;
                        } else if (msg_type ==
                                   to_string(mtx::events::EventType::KeyVerificationKey)) {
                                ChatPage::instance()->receivedDeviceVerificationKey(
                                  payload["content"]);
                                return;
                        } else if (msg_type ==
                                   to_string(mtx::events::EventType::KeyVerificationMac)) {
                                ChatPage::instance()->receivedDeviceVerificationMac(
                                  payload["content"]);
                                return;
                        } else if (msg_type ==
                                   to_string(mtx::events::EventType::KeyVerificationStart)) {
                                ChatPage::instance()->receivedDeviceVerificationStart(
                                  payload["content"], payload["sender"]);
                                return;
                        } else if (msg_type ==
                                   to_string(mtx::events::EventType::KeyVerificationReady)) {
                                ChatPage::instance()->receivedDeviceVerificationReady(
                                  payload["content"]);
                                return;
                        } else if (msg_type ==
                                   to_string(mtx::events::EventType::KeyVerificationDone)) {
                                ChatPage::instance()->receivedDeviceVerificationDone(
                                  payload["content"]);
                                return;
                        } else if (msg_type == to_string(mtx::events::EventType::RoomKey)) {
                                mtx::events::DeviceEvent<mtx::events::msg::RoomKey> roomKey =
                                  payload;
                                create_inbound_megolm_session(roomKey, msg.sender_key);
                                return;
                        } else if (msg_type ==
                                   to_string(mtx::events::EventType::ForwardedRoomKey)) {
                                mtx::events::DeviceEvent<mtx::events::msg::ForwardedRoomKey>
                                  roomKey = payload;
                                import_inbound_megolm_session(roomKey);
                                return;
                        }
                }
        }
}

nlohmann::json
handle_pre_key_olm_message(const std::string &sender,
                           const std::string &sender_key,
                           const mtx::events::msg::OlmCipherContent &content)
{
        nhlog::crypto()->info("opening olm session with {}", sender);

        mtx::crypto::OlmSessionPtr inbound_session = nullptr;
        try {
                inbound_session =
                  olm::client()->create_inbound_session_from(sender_key, content.body);

                // We also remove the one time key used to establish that
                // session so we'll have to update our copy of the account object.
                cache::saveOlmAccount(olm::client()->save("secret"));
        } catch (const mtx::crypto::olm_exception &e) {
                nhlog::crypto()->critical(
                  "failed to create inbound session with {}: {}", sender, e.what());
                return {};
        }

        if (!mtx::crypto::matches_inbound_session_from(
              inbound_session.get(), sender_key, content.body)) {
                nhlog::crypto()->warn("inbound olm session doesn't match sender's key ({})",
                                      sender);
                return {};
        }

        mtx::crypto::BinaryBuf output;
        try {
                output =
                  olm::client()->decrypt_message(inbound_session.get(), content.type, content.body);
        } catch (const mtx::crypto::olm_exception &e) {
                nhlog::crypto()->critical(
                  "failed to decrypt olm message {}: {}", content.body, e.what());
                return {};
        }

        auto plaintext = json::parse(std::string((char *)output.data(), output.size()));
        nhlog::crypto()->debug("decrypted message: \n {}", plaintext.dump(2));

        try {
                nhlog::crypto()->debug("New olm session: {}",
                                       mtx::crypto::session_id(inbound_session.get()));
                cache::saveOlmSession(
                  sender_key, std::move(inbound_session), QDateTime::currentMSecsSinceEpoch());
        } catch (const lmdb::error &e) {
                nhlog::db()->warn(
                  "failed to save inbound olm session from {}: {}", sender, e.what());
        }

        return plaintext;
}

mtx::events::msg::Encrypted
encrypt_group_message(const std::string &room_id, const std::string &device_id, nlohmann::json body)
{
        using namespace mtx::events;

        // relations shouldn't be encrypted...
        mtx::common::ReplyRelatesTo relation;
        mtx::common::RelatesTo r_relation;

        if (body["content"].contains("m.relates_to") &&
            body["content"]["m.relates_to"].contains("m.in_reply_to")) {
                relation = body["content"]["m.relates_to"];
                body["content"].erase("m.relates_to");
        } else if (body["content"]["m.relates_to"].contains("event_id")) {
                r_relation = body["content"]["m.relates_to"];
                body["content"].erase("m.relates_to");
        }

        // Always check before for existence.
        auto res     = cache::getOutboundMegolmSession(room_id);
        auto payload = olm::client()->encrypt_group_message(res.session, body.dump());

        // Prepare the m.room.encrypted event.
        msg::Encrypted data;
        data.ciphertext   = std::string((char *)payload.data(), payload.size());
        data.sender_key   = olm::client()->identity_keys().curve25519;
        data.session_id   = res.data.session_id;
        data.device_id    = device_id;
        data.algorithm    = MEGOLM_ALGO;
        data.relates_to   = relation;
        data.r_relates_to = r_relation;

        auto message_index = olm_outbound_group_session_message_index(res.session);
        nhlog::crypto()->debug("next message_index {}", message_index);

        // We need to re-pickle the session after we send a message to save the new message_index.
        cache::updateOutboundMegolmSession(room_id, message_index);

        return data;
}

nlohmann::json
try_olm_decryption(const std::string &sender_key, const mtx::events::msg::OlmCipherContent &msg)
{
        auto session_ids = cache::getOlmSessions(sender_key);

        nhlog::crypto()->info("attempt to decrypt message with {} known session_ids",
                              session_ids.size());

        for (const auto &id : session_ids) {
                auto session = cache::getOlmSession(sender_key, id);

                if (!session)
                        continue;

                mtx::crypto::BinaryBuf text;

                try {
                        text = olm::client()->decrypt_message(session->get(), msg.type, msg.body);
                        nhlog::crypto()->debug("Updated olm session: {}",
                                               mtx::crypto::session_id(session->get()));
                        cache::saveOlmSession(
                          id, std::move(session.value()), QDateTime::currentMSecsSinceEpoch());
                } catch (const mtx::crypto::olm_exception &e) {
                        nhlog::crypto()->debug("failed to decrypt olm message ({}, {}) with {}: {}",
                                               msg.type,
                                               sender_key,
                                               id,
                                               e.what());
                        continue;
                } catch (const lmdb::error &e) {
                        nhlog::crypto()->critical("failed to save session: {}", e.what());
                        return {};
                }

                try {
                        return json::parse(std::string_view((char *)text.data(), text.size()));
                } catch (const json::exception &e) {
                        nhlog::crypto()->critical(
                          "failed to parse the decrypted session msg: {} {}",
                          e.what(),
                          std::string_view((char *)text.data(), text.size()));
                }
        }

        return {};
}

void
create_inbound_megolm_session(const mtx::events::DeviceEvent<mtx::events::msg::RoomKey> &roomKey,
                              const std::string &sender_key)
{
        MegolmSessionIndex index;
        index.room_id    = roomKey.content.room_id;
        index.session_id = roomKey.content.session_id;
        index.sender_key = sender_key;

        try {
                auto megolm_session =
                  olm::client()->init_inbound_group_session(roomKey.content.session_key);
                cache::saveInboundMegolmSession(index, std::move(megolm_session));
        } catch (const lmdb::error &e) {
                nhlog::crypto()->critical("failed to save inbound megolm session: {}", e.what());
                return;
        } catch (const mtx::crypto::olm_exception &e) {
                nhlog::crypto()->critical("failed to create inbound megolm session: {}", e.what());
                return;
        }

        nhlog::crypto()->info(
          "established inbound megolm session ({}, {})", roomKey.content.room_id, roomKey.sender);

        ChatPage::instance()->receivedSessionKey(index.room_id, index.session_id);
}

void
import_inbound_megolm_session(
  const mtx::events::DeviceEvent<mtx::events::msg::ForwardedRoomKey> &roomKey)
{
        MegolmSessionIndex index;
        index.room_id    = roomKey.content.room_id;
        index.session_id = roomKey.content.session_id;
        index.sender_key = roomKey.content.sender_key;

        try {
                auto megolm_session =
                  olm::client()->import_inbound_group_session(roomKey.content.session_key);
                cache::saveInboundMegolmSession(index, std::move(megolm_session));
        } catch (const lmdb::error &e) {
                nhlog::crypto()->critical("failed to save inbound megolm session: {}", e.what());
                return;
        } catch (const mtx::crypto::olm_exception &e) {
                nhlog::crypto()->critical("failed to import inbound megolm session: {}", e.what());
                return;
        }

        nhlog::crypto()->info(
          "established inbound megolm session ({}, {})", roomKey.content.room_id, roomKey.sender);

        ChatPage::instance()->receivedSessionKey(index.room_id, index.session_id);
}

void
mark_keys_as_published()
{
        olm::client()->mark_keys_as_published();
        cache::saveOlmAccount(olm::client()->save(STORAGE_SECRET_KEY));
}

void
send_key_request_for(mtx::events::EncryptedEvent<mtx::events::msg::Encrypted> e,
                     const std::string &request_id,
                     bool cancel)
{
        using namespace mtx::events;

        nhlog::crypto()->debug("sending key request: sender_key {}, session_id {}",
                               e.content.sender_key,
                               e.content.session_id);

        mtx::events::msg::KeyRequest request;
        request.action               = !cancel ? mtx::events::msg::RequestAction::Request
                                               : mtx::events::msg::RequestAction::Cancellation;
        request.algorithm            = MEGOLM_ALGO;
        request.room_id              = e.room_id;
        request.sender_key           = e.content.sender_key;
        request.session_id           = e.content.session_id;
        request.request_id           = request_id;
        request.requesting_device_id = http::client()->device_id();

        nhlog::crypto()->debug("m.room_key_request: {}", json(request).dump(2));

        std::map<mtx::identifiers::User, std::map<std::string, decltype(request)>> body;
        body[mtx::identifiers::parse<mtx::identifiers::User>(e.sender)][e.content.device_id] =
          request;
        body[http::client()->user_id()]["*"] = request;

        http::client()->send_to_device(
          http::client()->generate_txn_id(), body, [e](mtx::http::RequestErr err) {
                  if (err) {
                          nhlog::net()->warn("failed to send "
                                             "send_to_device "
                                             "message: {}",
                                             err->matrix_error.error);
                  }

                  nhlog::net()->info("m.room_key_request sent to {}:{} and your own devices",
                                     e.sender,
                                     e.content.device_id);
          });
}

void
handle_key_request_message(const mtx::events::DeviceEvent<mtx::events::msg::KeyRequest> &req)
{
        if (req.content.algorithm != MEGOLM_ALGO) {
                nhlog::crypto()->debug("ignoring key request {} with invalid algorithm: {}",
                                       req.content.request_id,
                                       req.content.algorithm);
                return;
        }

        // Check if we were the sender of the session being requested.
        if (req.content.sender_key != olm::client()->identity_keys().curve25519) {
                nhlog::crypto()->debug("ignoring key request {} because we were not the sender: "
                                       "\nrequested({}) ours({})",
                                       req.content.request_id,
                                       req.content.sender_key,
                                       olm::client()->identity_keys().curve25519);
                return;
        }

        // Check if we have the keys for the requested session.
        if (!cache::outboundMegolmSessionExists(req.content.room_id)) {
                nhlog::crypto()->warn("requested session not found in room: {}",
                                      req.content.room_id);

                return;
        }

        // Check that the requested session_id and the one we have saved match.
        MegolmSessionIndex index{};
        index.room_id    = req.content.room_id;
        index.session_id = req.content.session_id;
        index.sender_key = olm::client()->identity_keys().curve25519;

        const auto session = cache::getInboundMegolmSession(index);
        if (!session) {
                nhlog::crypto()->warn("No session with id {} in db", req.content.session_id);
                return;
        }

        if (!cache::isRoomMember(req.sender, req.content.room_id)) {
                nhlog::crypto()->warn(
                  "user {} that requested the session key is not member of the room {}",
                  req.sender,
                  req.content.room_id);
                return;
        }

        // check if device is verified
        auto verificationStatus = cache::verificationStatus(req.sender);
        bool verifiedDevice     = false;
        if (verificationStatus &&
            ChatPage::instance()->userSettings()->shareKeysWithTrustedUsers()) {
                for (const auto &dev : verificationStatus->verified_devices) {
                        if (dev == req.content.requesting_device_id) {
                                verifiedDevice = true;
                                nhlog::crypto()->debug("Verified device: {}", dev);
                                break;
                        }
                }
        }

        if (!utils::respondsToKeyRequests(req.content.room_id) && !verifiedDevice) {
                nhlog::crypto()->debug("ignoring all key requests for room {}",
                                       req.content.room_id);
                return;
        }

        auto session_key = mtx::crypto::export_session(session);
        //
        // Prepare the m.room_key event.
        //
        mtx::events::msg::ForwardedRoomKey forward_key{};
        forward_key.algorithm   = MEGOLM_ALGO;
        forward_key.room_id     = index.room_id;
        forward_key.session_id  = index.session_id;
        forward_key.session_key = session_key;
        forward_key.sender_key  = index.sender_key;

        // TODO(Nico): Figure out if this is correct
        forward_key.sender_claimed_ed25519_key      = olm::client()->identity_keys().ed25519;
        forward_key.forwarding_curve25519_key_chain = {};

        send_megolm_key_to_device(req.sender, req.content.requesting_device_id, forward_key);
}

void
send_megolm_key_to_device(const std::string &user_id,
                          const std::string &device_id,
                          const mtx::events::msg::ForwardedRoomKey &payload)
{
        mtx::events::DeviceEvent<mtx::events::msg::ForwardedRoomKey> room_key;
        room_key.content = payload;
        room_key.type    = mtx::events::EventType::ForwardedRoomKey;

        std::map<std::string, std::vector<std::string>> targets;
        targets[user_id] = {device_id};
        send_encrypted_to_device_messages(targets, room_key);
}

DecryptionResult
decryptEvent(const MegolmSessionIndex &index,
             const mtx::events::EncryptedEvent<mtx::events::msg::Encrypted> &event)
{
        try {
                if (!cache::client()->inboundMegolmSessionExists(index)) {
                        return {DecryptionErrorCode::MissingSession, std::nullopt, std::nullopt};
                }
        } catch (const lmdb::error &e) {
                return {DecryptionErrorCode::DbError, e.what(), std::nullopt};
        }

        // TODO: Lookup index,event_id,origin_server_ts tuple for replay attack errors
        // TODO: Verify sender_key

        std::string msg_str;
        try {
                auto session = cache::client()->getInboundMegolmSession(index);
                auto res = olm::client()->decrypt_group_message(session, event.content.ciphertext);
                msg_str  = std::string((char *)res.data.data(), res.data.size());
        } catch (const lmdb::error &e) {
                return {DecryptionErrorCode::DbError, e.what(), std::nullopt};
        } catch (const mtx::crypto::olm_exception &e) {
                return {DecryptionErrorCode::DecryptionFailed, e.what(), std::nullopt};
        }

        // Add missing fields for the event.
        json body                = json::parse(msg_str);
        body["event_id"]         = event.event_id;
        body["sender"]           = event.sender;
        body["origin_server_ts"] = event.origin_server_ts;
        body["unsigned"]         = event.unsigned_data;

        // relations are unencrypted in content...
        if (json old_ev = event; old_ev["content"].count("m.relates_to") != 0)
                body["content"]["m.relates_to"] = old_ev["content"]["m.relates_to"];

        mtx::events::collections::TimelineEvent te;
        try {
                mtx::events::collections::from_json(body, te);
        } catch (std::exception &e) {
                return {DecryptionErrorCode::ParsingFailed, e.what(), std::nullopt};
        }

        return {std::nullopt, std::nullopt, std::move(te.data)};
}

//! Send encrypted to device messages, targets is a map from userid to device ids or {} for all
//! devices
void
send_encrypted_to_device_messages(const std::map<std::string, std::vector<std::string>> targets,
                                  const mtx::events::collections::DeviceEvents &event,
                                  bool force_new_session)
{
        nlohmann::json ev_json = std::visit([](const auto &e) { return json(e); }, event);

        std::map<std::string, std::vector<std::string>> keysToQuery;
        mtx::requests::ClaimKeys claims;
        std::map<mtx::identifiers::User, std::map<std::string, mtx::events::msg::OlmEncrypted>>
          messages;
        std::map<std::string, std::map<std::string, DevicePublicKeys>> pks;

        for (const auto &[user, devices] : targets) {
                auto deviceKeys = cache::client()->userKeys(user);

                // no keys for user, query them
                if (!deviceKeys) {
                        keysToQuery[user] = devices;
                        continue;
                }

                auto deviceTargets = devices;
                if (devices.empty()) {
                        deviceTargets.clear();
                        for (const auto &[device, keys] : deviceKeys->device_keys) {
                                (void)keys;
                                deviceTargets.push_back(device);
                        }
                }

                for (const auto &device : deviceTargets) {
                        if (!deviceKeys->device_keys.count(device)) {
                                keysToQuery[user] = {};
                                break;
                        }

                        auto d = deviceKeys->device_keys.at(device);

                        auto session =
                          cache::getLatestOlmSession(d.keys.at("curve25519:" + device));
                        if (!session || force_new_session) {
                                claims.one_time_keys[user][device] = mtx::crypto::SIGNED_CURVE25519;
                                pks[user][device].ed25519          = d.keys.at("ed25519:" + device);
                                pks[user][device].curve25519 = d.keys.at("curve25519:" + device);
                                continue;
                        }

                        messages[mtx::identifiers::parse<mtx::identifiers::User>(user)][device] =
                          olm::client()
                            ->create_olm_encrypted_content(session->get(),
                                                           ev_json,
                                                           UserId(user),
                                                           d.keys.at("ed25519:" + device),
                                                           d.keys.at("curve25519:" + device))
                            .get<mtx::events::msg::OlmEncrypted>();

                        try {
                                nhlog::crypto()->debug("Updated olm session: {}",
                                                       mtx::crypto::session_id(session->get()));
                                cache::saveOlmSession(d.keys.at("curve25519:" + device),
                                                      std::move(*session),
                                                      QDateTime::currentMSecsSinceEpoch());
                        } catch (const lmdb::error &e) {
                                nhlog::db()->critical("failed to save outbound olm session: {}",
                                                      e.what());
                        } catch (const mtx::crypto::olm_exception &e) {
                                nhlog::crypto()->critical(
                                  "failed to pickle outbound olm session: {}", e.what());
                        }
                }
        }

        if (!messages.empty())
                http::client()->send_to_device<mtx::events::msg::OlmEncrypted>(
                  http::client()->generate_txn_id(), messages, [](mtx::http::RequestErr err) {
                          if (err) {
                                  nhlog::net()->warn("failed to send "
                                                     "send_to_device "
                                                     "message: {}",
                                                     err->matrix_error.error);
                          }
                  });

        auto BindPks = [ev_json](decltype(pks) pks_temp) {
                return [pks = pks_temp, ev_json](const mtx::responses::ClaimKeys &res,
                                                 mtx::http::RequestErr) {
                        std::map<mtx::identifiers::User,
                                 std::map<std::string, mtx::events::msg::OlmEncrypted>>
                          messages;
                        for (const auto &[user_id, retrieved_devices] : res.one_time_keys) {
                                nhlog::net()->debug("claimed keys for {}", user_id);
                                if (retrieved_devices.size() == 0) {
                                        nhlog::net()->debug(
                                          "no one-time keys found for user_id: {}", user_id);
                                        continue;
                                }

                                for (const auto &rd : retrieved_devices) {
                                        const auto device_id = rd.first;

                                        nhlog::net()->debug(
                                          "{} : \n {}", device_id, rd.second.dump(2));

                                        if (rd.second.empty() ||
                                            !rd.second.begin()->contains("key")) {
                                                nhlog::net()->warn(
                                                  "Skipping device {} as it has no key.",
                                                  device_id);
                                                continue;
                                        }

                                        // TODO: Verify signatures
                                        auto otk = rd.second.begin()->at("key");

                                        auto id_key = pks.at(user_id).at(device_id).curve25519;
                                        auto session =
                                          olm::client()->create_outbound_session(id_key, otk);

                                        messages[mtx::identifiers::parse<mtx::identifiers::User>(
                                          user_id)][device_id] =
                                          olm::client()
                                            ->create_olm_encrypted_content(
                                              session.get(),
                                              ev_json,
                                              UserId(user_id),
                                              pks.at(user_id).at(device_id).ed25519,
                                              id_key)
                                            .get<mtx::events::msg::OlmEncrypted>();

                                        try {
                                                nhlog::crypto()->debug(
                                                  "Updated olm session: {}",
                                                  mtx::crypto::session_id(session.get()));
                                                cache::saveOlmSession(
                                                  id_key,
                                                  std::move(session),
                                                  QDateTime::currentMSecsSinceEpoch());
                                        } catch (const lmdb::error &e) {
                                                nhlog::db()->critical(
                                                  "failed to save outbound olm session: {}",
                                                  e.what());
                                        } catch (const mtx::crypto::olm_exception &e) {
                                                nhlog::crypto()->critical(
                                                  "failed to pickle outbound olm session: {}",
                                                  e.what());
                                        }
                                }
                                nhlog::net()->info("send_to_device: {}", user_id);
                        }

                        if (!messages.empty())
                                http::client()->send_to_device<mtx::events::msg::OlmEncrypted>(
                                  http::client()->generate_txn_id(),
                                  messages,
                                  [](mtx::http::RequestErr err) {
                                          if (err) {
                                                  nhlog::net()->warn("failed to send "
                                                                     "send_to_device "
                                                                     "message: {}",
                                                                     err->matrix_error.error);
                                          }
                                  });
                };
        };

        http::client()->claim_keys(claims, BindPks(pks));

        if (!keysToQuery.empty()) {
                mtx::requests::QueryKeys req;
                req.device_keys = keysToQuery;
                http::client()->query_keys(
                  req,
                  [ev_json, BindPks](const mtx::responses::QueryKeys &res,
                                     mtx::http::RequestErr err) {
                          if (err) {
                                  nhlog::net()->warn("failed to query device keys: {} {}",
                                                     err->matrix_error.error,
                                                     static_cast<int>(err->status_code));
                                  return;
                          }

                          nhlog::net()->info("queried keys");

                          cache::client()->updateUserKeys(cache::nextBatchToken(), res);

                          mtx::requests::ClaimKeys claim_keys;

                          std::map<std::string, std::map<std::string, DevicePublicKeys>> deviceKeys;

                          for (const auto &user : res.device_keys) {
                                  for (const auto &dev : user.second) {
                                          const auto user_id   = ::UserId(dev.second.user_id);
                                          const auto device_id = DeviceId(dev.second.device_id);

                                          if (user_id.get() ==
                                                http::client()->user_id().to_string() &&
                                              device_id.get() == http::client()->device_id())
                                                  continue;

                                          const auto device_keys = dev.second.keys;
                                          const auto curveKey    = "curve25519:" + device_id.get();
                                          const auto edKey       = "ed25519:" + device_id.get();

                                          if ((device_keys.find(curveKey) == device_keys.end()) ||
                                              (device_keys.find(edKey) == device_keys.end())) {
                                                  nhlog::net()->debug(
                                                    "ignoring malformed keys for device {}",
                                                    device_id.get());
                                                  continue;
                                          }

                                          DevicePublicKeys pks;
                                          pks.ed25519    = device_keys.at(edKey);
                                          pks.curve25519 = device_keys.at(curveKey);

                                          try {
                                                  if (!mtx::crypto::verify_identity_signature(
                                                        dev.second, device_id, user_id)) {
                                                          nhlog::crypto()->warn(
                                                            "failed to verify identity keys: {}",
                                                            json(dev.second).dump(2));
                                                          continue;
                                                  }
                                          } catch (const json::exception &e) {
                                                  nhlog::crypto()->warn(
                                                    "failed to parse device key json: {}",
                                                    e.what());
                                                  continue;
                                          } catch (const mtx::crypto::olm_exception &e) {
                                                  nhlog::crypto()->warn(
                                                    "failed to verify device key json: {}",
                                                    e.what());
                                                  continue;
                                          }

                                          deviceKeys[user_id].emplace(device_id, pks);
                                          claim_keys.one_time_keys[user.first][device_id] =
                                            mtx::crypto::SIGNED_CURVE25519;

                                          nhlog::net()->info("{}", device_id.get());
                                          nhlog::net()->info("  curve25519 {}", pks.curve25519);
                                          nhlog::net()->info("  ed25519 {}", pks.ed25519);
                                  }
                          }

                          http::client()->claim_keys(claim_keys, BindPks(deviceKeys));
                  });
        }
}

} // namespace olm