549 lines
23 KiB
C++
549 lines
23 KiB
C++
#include <variant>
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#include "Olm.h"
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#include "Cache.h"
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#include "Logging.h"
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#include "MatrixClient.h"
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#include "Utils.h"
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static const std::string STORAGE_SECRET_KEY("secret");
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constexpr auto MEGOLM_ALGO = "m.megolm.v1.aes-sha2";
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namespace {
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auto client_ = std::make_unique<mtx::crypto::OlmClient>();
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}
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namespace olm {
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mtx::crypto::OlmClient *
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client()
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{
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return client_.get();
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}
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void
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handle_to_device_messages(const std::vector<nlohmann::json> &msgs)
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{
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if (msgs.empty())
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return;
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nhlog::crypto()->info("received {} to_device messages", msgs.size());
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for (const auto &msg : msgs) {
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if (msg.count("type") == 0) {
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nhlog::crypto()->warn("received message with no type field: {}",
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msg.dump(2));
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continue;
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}
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std::string msg_type = msg.at("type");
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if (msg_type == to_string(mtx::events::EventType::RoomEncrypted)) {
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try {
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OlmMessage olm_msg = msg;
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handle_olm_message(std::move(olm_msg));
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} catch (const nlohmann::json::exception &e) {
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nhlog::crypto()->warn(
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"parsing error for olm message: {} {}", e.what(), msg.dump(2));
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} catch (const std::invalid_argument &e) {
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nhlog::crypto()->warn(
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"validation error for olm message: {} {}", e.what(), msg.dump(2));
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}
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} else if (msg_type == to_string(mtx::events::EventType::RoomKeyRequest)) {
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nhlog::crypto()->warn("handling key request event: {}", msg.dump(2));
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try {
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mtx::events::msg::KeyRequest req = msg;
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if (req.action == mtx::events::msg::RequestAction::Request)
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handle_key_request_message(std::move(req));
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else
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nhlog::crypto()->warn(
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"ignore key request (unhandled action): {}",
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req.request_id);
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} catch (const nlohmann::json::exception &e) {
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nhlog::crypto()->warn(
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"parsing error for key_request message: {} {}",
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e.what(),
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msg.dump(2));
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}
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} else {
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nhlog::crypto()->warn("unhandled event: {}", msg.dump(2));
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}
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}
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}
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void
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handle_olm_message(const OlmMessage &msg)
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{
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nhlog::crypto()->info("sender : {}", msg.sender);
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nhlog::crypto()->info("sender_key: {}", msg.sender_key);
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const auto my_key = olm::client()->identity_keys().curve25519;
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for (const auto &cipher : msg.ciphertext) {
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// We skip messages not meant for the current device.
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if (cipher.first != my_key)
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continue;
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const auto type = cipher.second.type;
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nhlog::crypto()->info("type: {}", type == 0 ? "OLM_PRE_KEY" : "OLM_MESSAGE");
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auto payload = try_olm_decryption(msg.sender_key, cipher.second);
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if (!payload.is_null()) {
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nhlog::crypto()->debug("decrypted olm payload: {}", payload.dump(2));
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create_inbound_megolm_session(msg.sender, msg.sender_key, payload);
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return;
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}
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// Not a PRE_KEY message
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if (cipher.second.type != 0) {
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// TODO: log that it should have matched something
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return;
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}
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handle_pre_key_olm_message(msg.sender, msg.sender_key, cipher.second);
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}
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}
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void
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handle_pre_key_olm_message(const std::string &sender,
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const std::string &sender_key,
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const mtx::events::msg::OlmCipherContent &content)
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{
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nhlog::crypto()->info("opening olm session with {}", sender);
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mtx::crypto::OlmSessionPtr inbound_session = nullptr;
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try {
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inbound_session =
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olm::client()->create_inbound_session_from(sender_key, content.body);
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// We also remove the one time key used to establish that
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// session so we'll have to update our copy of the account object.
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cache::saveOlmAccount(olm::client()->save("secret"));
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} catch (const mtx::crypto::olm_exception &e) {
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nhlog::crypto()->critical(
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"failed to create inbound session with {}: {}", sender, e.what());
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return;
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}
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if (!mtx::crypto::matches_inbound_session_from(
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inbound_session.get(), sender_key, content.body)) {
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nhlog::crypto()->warn("inbound olm session doesn't match sender's key ({})",
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sender);
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return;
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}
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mtx::crypto::BinaryBuf output;
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try {
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output =
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olm::client()->decrypt_message(inbound_session.get(), content.type, content.body);
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} catch (const mtx::crypto::olm_exception &e) {
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nhlog::crypto()->critical(
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"failed to decrypt olm message {}: {}", content.body, e.what());
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return;
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}
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auto plaintext = json::parse(std::string((char *)output.data(), output.size()));
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nhlog::crypto()->debug("decrypted message: \n {}", plaintext.dump(2));
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try {
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cache::saveOlmSession(sender_key, std::move(inbound_session));
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} catch (const lmdb::error &e) {
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nhlog::db()->warn(
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"failed to save inbound olm session from {}: {}", sender, e.what());
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}
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create_inbound_megolm_session(sender, sender_key, plaintext);
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}
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mtx::events::msg::Encrypted
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encrypt_group_message(const std::string &room_id, const std::string &device_id, nlohmann::json body)
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{
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using namespace mtx::events;
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// relations shouldn't be encrypted...
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mtx::common::RelatesTo relation;
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if (body["content"].count("m.relates_to") != 0) {
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relation = body["content"]["m.relates_to"];
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body["content"].erase("m.relates_to");
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}
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// Always check before for existence.
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auto res = cache::getOutboundMegolmSession(room_id);
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auto payload = olm::client()->encrypt_group_message(res.session, body.dump());
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// Prepare the m.room.encrypted event.
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msg::Encrypted data;
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data.ciphertext = std::string((char *)payload.data(), payload.size());
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data.sender_key = olm::client()->identity_keys().curve25519;
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data.session_id = res.data.session_id;
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data.device_id = device_id;
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data.algorithm = MEGOLM_ALGO;
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data.relates_to = relation;
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auto message_index = olm_outbound_group_session_message_index(res.session);
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nhlog::crypto()->debug("next message_index {}", message_index);
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// We need to re-pickle the session after we send a message to save the new message_index.
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cache::updateOutboundMegolmSession(room_id, message_index);
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return data;
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}
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nlohmann::json
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try_olm_decryption(const std::string &sender_key, const mtx::events::msg::OlmCipherContent &msg)
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{
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auto session_ids = cache::getOlmSessions(sender_key);
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nhlog::crypto()->info("attempt to decrypt message with {} known session_ids",
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session_ids.size());
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for (const auto &id : session_ids) {
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auto session = cache::getOlmSession(sender_key, id);
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if (!session)
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continue;
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mtx::crypto::BinaryBuf text;
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try {
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text = olm::client()->decrypt_message(session->get(), msg.type, msg.body);
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cache::saveOlmSession(id, std::move(session.value()));
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} catch (const mtx::crypto::olm_exception &e) {
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nhlog::crypto()->debug("failed to decrypt olm message ({}, {}) with {}: {}",
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msg.type,
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sender_key,
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id,
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e.what());
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continue;
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} catch (const lmdb::error &e) {
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nhlog::crypto()->critical("failed to save session: {}", e.what());
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return {};
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}
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try {
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return json::parse(std::string((char *)text.data(), text.size()));
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} catch (const json::exception &e) {
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nhlog::crypto()->critical("failed to parse the decrypted session msg: {}",
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e.what());
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}
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}
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return {};
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}
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void
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create_inbound_megolm_session(const std::string &sender,
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const std::string &sender_key,
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const nlohmann::json &payload)
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{
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std::string room_id, session_id, session_key;
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try {
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room_id = payload.at("content").at("room_id");
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session_id = payload.at("content").at("session_id");
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session_key = payload.at("content").at("session_key");
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} catch (const nlohmann::json::exception &e) {
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nhlog::crypto()->critical(
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"failed to parse plaintext olm message: {} {}", e.what(), payload.dump(2));
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return;
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}
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MegolmSessionIndex index;
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index.room_id = room_id;
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index.session_id = session_id;
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index.sender_key = sender_key;
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try {
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auto megolm_session = olm::client()->init_inbound_group_session(session_key);
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cache::saveInboundMegolmSession(index, std::move(megolm_session));
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} catch (const lmdb::error &e) {
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nhlog::crypto()->critical("failed to save inbound megolm session: {}", e.what());
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return;
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} catch (const mtx::crypto::olm_exception &e) {
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nhlog::crypto()->critical("failed to create inbound megolm session: {}", e.what());
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return;
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}
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nhlog::crypto()->info("established inbound megolm session ({}, {})", room_id, sender);
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}
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void
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mark_keys_as_published()
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{
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olm::client()->mark_keys_as_published();
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cache::saveOlmAccount(olm::client()->save(STORAGE_SECRET_KEY));
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}
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void
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request_keys(const std::string &room_id, const std::string &event_id)
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{
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nhlog::crypto()->info("requesting keys for event {} at {}", event_id, room_id);
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http::client()->get_event(
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room_id,
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event_id,
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[event_id, room_id](const mtx::events::collections::TimelineEvents &res,
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mtx::http::RequestErr err) {
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using namespace mtx::events;
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if (err) {
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nhlog::net()->warn(
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"failed to retrieve event {} from {}", event_id, room_id);
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return;
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}
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if (!std::holds_alternative<EncryptedEvent<msg::Encrypted>>(res)) {
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nhlog::net()->info(
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"retrieved event is not encrypted: {} from {}", event_id, room_id);
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return;
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}
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olm::send_key_request_for(room_id, std::get<EncryptedEvent<msg::Encrypted>>(res));
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});
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}
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void
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send_key_request_for(const std::string &room_id,
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const mtx::events::EncryptedEvent<mtx::events::msg::Encrypted> &e)
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{
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using namespace mtx::events;
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nhlog::crypto()->debug("sending key request: {}", json(e).dump(2));
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auto payload = json{{"action", "request"},
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{"request_id", http::client()->generate_txn_id()},
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{"requesting_device_id", http::client()->device_id()},
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{"body",
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{{"algorithm", MEGOLM_ALGO},
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{"room_id", room_id},
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{"sender_key", e.content.sender_key},
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{"session_id", e.content.session_id}}}};
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json body;
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body["messages"][e.sender] = json::object();
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body["messages"][e.sender][e.content.device_id] = payload;
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nhlog::crypto()->debug("m.room_key_request: {}", body.dump(2));
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http::client()->send_to_device("m.room_key_request", body, [e](mtx::http::RequestErr err) {
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if (err) {
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nhlog::net()->warn("failed to send "
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"send_to_device "
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"message: {}",
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err->matrix_error.error);
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}
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nhlog::net()->info(
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"m.room_key_request sent to {}:{}", e.sender, e.content.device_id);
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});
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}
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void
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handle_key_request_message(const mtx::events::msg::KeyRequest &req)
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{
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if (req.algorithm != MEGOLM_ALGO) {
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nhlog::crypto()->debug("ignoring key request {} with invalid algorithm: {}",
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req.request_id,
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req.algorithm);
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return;
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}
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// Check if we were the sender of the session being requested.
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if (req.sender_key != olm::client()->identity_keys().curve25519) {
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nhlog::crypto()->debug("ignoring key request {} because we were not the sender: "
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"\nrequested({}) ours({})",
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req.request_id,
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req.sender_key,
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olm::client()->identity_keys().curve25519);
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return;
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}
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// Check if we have the keys for the requested session.
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if (!cache::outboundMegolmSessionExists(req.room_id)) {
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nhlog::crypto()->warn("requested session not found in room: {}", req.room_id);
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return;
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}
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// Check that the requested session_id and the one we have saved match.
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const auto session = cache::getOutboundMegolmSession(req.room_id);
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if (req.session_id != session.data.session_id) {
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nhlog::crypto()->warn("session id of retrieved session doesn't match the request: "
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"requested({}), ours({})",
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req.session_id,
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session.data.session_id);
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return;
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}
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if (!cache::isRoomMember(req.sender, req.room_id)) {
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nhlog::crypto()->warn(
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"user {} that requested the session key is not member of the room {}",
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req.sender,
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req.room_id);
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return;
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}
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if (!utils::respondsToKeyRequests(req.room_id)) {
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nhlog::crypto()->debug("ignoring all key requests for room {}", req.room_id);
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return;
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}
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//
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// Prepare the m.room_key event.
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//
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auto payload = json{{"algorithm", "m.megolm.v1.aes-sha2"},
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{"room_id", req.room_id},
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{"session_id", req.session_id},
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{"session_key", session.data.session_key}};
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send_megolm_key_to_device(req.sender, req.requesting_device_id, payload);
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}
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void
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send_megolm_key_to_device(const std::string &user_id,
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const std::string &device_id,
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const json &payload)
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{
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mtx::requests::QueryKeys req;
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req.device_keys[user_id] = {device_id};
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http::client()->query_keys(
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req,
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[payload, user_id, device_id](const mtx::responses::QueryKeys &res,
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mtx::http::RequestErr err) {
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if (err) {
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nhlog::net()->warn("failed to query device keys: {} {}",
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err->matrix_error.error,
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static_cast<int>(err->status_code));
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return;
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}
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nhlog::net()->warn("retrieved device keys from {}, {}", user_id, device_id);
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if (res.device_keys.empty()) {
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nhlog::net()->warn("no devices retrieved {}", user_id);
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return;
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}
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auto device = res.device_keys.begin()->second;
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if (device.empty()) {
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nhlog::net()->warn("no keys retrieved from user, device {}", user_id);
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return;
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}
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const auto device_keys = device.begin()->second.keys;
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const auto curveKey = "curve25519:" + device_id;
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const auto edKey = "ed25519:" + device_id;
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if ((device_keys.find(curveKey) == device_keys.end()) ||
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(device_keys.find(edKey) == device_keys.end())) {
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nhlog::net()->debug("ignoring malformed keys for device {}", device_id);
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return;
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}
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DevicePublicKeys pks;
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pks.ed25519 = device_keys.at(edKey);
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pks.curve25519 = device_keys.at(curveKey);
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try {
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if (!mtx::crypto::verify_identity_signature(json(device.begin()->second),
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DeviceId(device_id),
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UserId(user_id))) {
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nhlog::crypto()->warn("failed to verify identity keys: {}",
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json(device).dump(2));
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return;
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}
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} catch (const json::exception &e) {
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nhlog::crypto()->warn("failed to parse device key json: {}", e.what());
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return;
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} catch (const mtx::crypto::olm_exception &e) {
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nhlog::crypto()->warn("failed to verify device key json: {}", e.what());
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return;
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}
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auto room_key = olm::client()
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->create_room_key_event(UserId(user_id), pks.ed25519, payload)
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.dump();
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http::client()->claim_keys(
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user_id,
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{device_id},
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[room_key, user_id, device_id, pks](const mtx::responses::ClaimKeys &res,
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mtx::http::RequestErr err) {
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if (err) {
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nhlog::net()->warn("claim keys error: {} {} {}",
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err->matrix_error.error,
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err->parse_error,
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static_cast<int>(err->status_code));
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return;
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}
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nhlog::net()->info("claimed keys for {}", user_id);
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if (res.one_time_keys.size() == 0) {
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nhlog::net()->info("no one-time keys found for user_id: {}",
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user_id);
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return;
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}
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if (res.one_time_keys.find(user_id) == res.one_time_keys.end()) {
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nhlog::net()->info("no one-time keys found for user_id: {}",
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user_id);
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return;
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}
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auto retrieved_devices = res.one_time_keys.at(user_id);
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if (retrieved_devices.empty()) {
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nhlog::net()->info("claiming keys for {}: no retrieved devices",
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device_id);
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return;
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}
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json body;
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body["messages"][user_id] = json::object();
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|
|
|
auto device = retrieved_devices.begin()->second;
|
|
nhlog::net()->debug("{} : \n {}", device_id, device.dump(2));
|
|
|
|
json device_msg;
|
|
|
|
try {
|
|
auto olm_session = olm::client()->create_outbound_session(
|
|
pks.curve25519, device.begin()->at("key"));
|
|
|
|
device_msg = olm::client()->create_olm_encrypted_content(
|
|
olm_session.get(), room_key, pks.curve25519);
|
|
|
|
cache::saveOlmSession(pks.curve25519, std::move(olm_session));
|
|
} catch (const json::exception &e) {
|
|
nhlog::crypto()->warn("creating outbound session: {}",
|
|
e.what());
|
|
return;
|
|
} catch (const mtx::crypto::olm_exception &e) {
|
|
nhlog::crypto()->warn("creating outbound session: {}",
|
|
e.what());
|
|
return;
|
|
}
|
|
|
|
body["messages"][user_id][device_id] = device_msg;
|
|
|
|
nhlog::net()->info(
|
|
"sending m.room_key event to {}:{}", user_id, device_id);
|
|
http::client()->send_to_device(
|
|
"m.room.encrypted", body, [user_id](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 send to {}", user_id);
|
|
});
|
|
});
|
|
});
|
|
}
|
|
|
|
} // namespace olm
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