remote auth impl. up to QR code display

1 files changed, 321 insertions, 0 deletions

diff --git a/src/remoteauth/remoteauthclient.cpp b/src/remoteauth/remoteauthclient.cpp
new file mode 100644
index 0000000..1ebb7cb
--- /dev/null
+++ b/src/remoteauth/remoteauthclient.cpp
@@ -0,0 +1,321 @@
+#include "remoteauthclient.hpp"
+#include <nlohmann/json.hpp>
+#include <spdlog/fmt/bin_to_hex.h>
+
+struct RemoteAuthGatewayMessage {
+    std::string Opcode;
+
+    friend void from_json(const nlohmann::json &j, RemoteAuthGatewayMessage &m) {
+        j.at("op").get_to(m.Opcode);
+    }
+};
+
+struct RemoteAuthHelloMessage {
+    int TimeoutMS;
+    int HeartbeatInterval;
+
+    friend void from_json(const nlohmann::json &j, RemoteAuthHelloMessage &m) {
+        j.at("timeout_ms").get_to(m.TimeoutMS);
+        j.at("heartbeat_interval").get_to(m.HeartbeatInterval);
+    }
+};
+
+struct RemoteAuthHeartbeatMessage {
+    friend void to_json(nlohmann::json &j, const RemoteAuthHeartbeatMessage &m) {
+        j["op"] = "heartbeat";
+    }
+};
+
+struct RemoteAuthInitMessage {
+    std::string EncodedPublicKey;
+
+    friend void to_json(nlohmann::json &j, const RemoteAuthInitMessage &m) {
+        j["op"] = "init";
+        j["encoded_public_key"] = m.EncodedPublicKey;
+    }
+};
+
+struct RemoteAuthNonceProofMessage {
+    std::string EncryptedNonce;
+    std::string Nonce;
+
+    friend void from_json(const nlohmann::json &j, RemoteAuthNonceProofMessage &m) {
+        j.at("encrypted_nonce").get_to(m.EncryptedNonce);
+    }
+
+    friend void to_json(nlohmann::json &j, const RemoteAuthNonceProofMessage &m) {
+        j["op"] = "nonce_proof";
+        j["nonce"] = m.Nonce;
+    }
+};
+
+struct RemoteAuthFingerprintMessage {
+    std::string Fingerprint;
+
+    friend void from_json(const nlohmann::json &j, RemoteAuthFingerprintMessage &m) {
+        j.at("fingerprint").get_to(m.Fingerprint);
+    }
+};
+
+struct RemoteAuthPendingTicketMessage {
+    std::string EncryptedUserPayload;
+
+    friend void from_json(const nlohmann::json &j, RemoteAuthPendingTicketMessage &m) {
+        j.at("encrypted_user_payload").get_to(m.EncryptedUserPayload);
+    }
+};
+
+RemoteAuthClient::RemoteAuthClient()
+    : m_ws("remote-auth-ws")
+    , m_log(spdlog::get("remote-auth")) {
+    m_ws.signal_open().connect(sigc::mem_fun(*this, &RemoteAuthClient::OnWebsocketOpen));
+    m_ws.signal_close().connect(sigc::mem_fun(*this, &RemoteAuthClient::OnWebsocketClose));
+    m_ws.signal_message().connect(sigc::mem_fun(*this, &RemoteAuthClient::OnWebsocketMessage));
+
+    m_dispatcher.connect(sigc::mem_fun(*this, &RemoteAuthClient::OnDispatch));
+}
+
+RemoteAuthClient::~RemoteAuthClient() {
+    Stop();
+}
+
+void RemoteAuthClient::Start() {
+    if (IsConnected()) {
+        Stop();
+    }
+
+    m_connected = true;
+    m_heartbeat_waiter.revive();
+    m_ws.StartConnection("wss://remote-auth-gateway.discord.gg/?v=2");
+}
+
+void RemoteAuthClient::Stop() {
+    if (!IsConnected()) {
+        m_log->warn("Requested stop while not connected");
+        return;
+    }
+
+    m_connected = false;
+    m_ws.Stop(1000);
+    m_heartbeat_waiter.kill();
+    if (m_heartbeat_thread.joinable()) m_heartbeat_thread.join();
+}
+
+bool RemoteAuthClient::IsConnected() const noexcept {
+    return m_connected;
+}
+
+void RemoteAuthClient::OnGatewayMessage(const std::string &str) {
+    auto j = nlohmann::json::parse(str);
+    RemoteAuthGatewayMessage msg = j;
+    if (msg.Opcode == "hello") {
+        HandleGatewayHello(j);
+    } else if (msg.Opcode == "nonce_proof") {
+        HandleGatewayNonceProof(j);
+    } else if (msg.Opcode == "pending_remote_init") {
+        HandleGatewayPendingRemoteInit(j);
+    } else if (msg.Opcode == "pending_ticket") {
+        HandleGatewayPendingTicket(j);
+    }
+}
+
+void RemoteAuthClient::HandleGatewayHello(const nlohmann::json &j) {
+    RemoteAuthHelloMessage msg = j;
+    m_log->debug("Timeout: {}, Heartbeat: {}", msg.TimeoutMS, msg.HeartbeatInterval);
+
+    m_heartbeat_msec = msg.HeartbeatInterval;
+    m_heartbeat_thread = std::thread(&RemoteAuthClient::HeartbeatThread, this);
+
+    Init();
+}
+
+void RemoteAuthClient::HandleGatewayNonceProof(const nlohmann::json &j) {
+    RemoteAuthNonceProofMessage msg = j;
+    m_log->debug("Received encrypted nonce");
+
+    const auto encrypted_nonce = Glib::Base64::decode(msg.EncryptedNonce);
+    const auto proof = Decrypt(reinterpret_cast<const unsigned char *>(encrypted_nonce.data()), encrypted_nonce.size());
+    auto proof_encoded = Glib::Base64::encode(std::string(proof.begin(), proof.end()));
+
+    std::replace(proof_encoded.begin(), proof_encoded.end(), '/', '_');
+    std::replace(proof_encoded.begin(), proof_encoded.end(), '+', '-');
+    proof_encoded.erase(std::remove(proof_encoded.begin(), proof_encoded.end(), '='), proof_encoded.end());
+
+    RemoteAuthNonceProofMessage reply;
+    reply.Nonce = proof_encoded;
+    m_ws.Send(reply);
+}
+
+void RemoteAuthClient::HandleGatewayPendingRemoteInit(const nlohmann::json &j) {
+    RemoteAuthFingerprintMessage msg = j;
+    m_log->debug("Received fingerprint");
+
+    m_signal_fingerprint.emit(msg.Fingerprint);
+}
+
+void RemoteAuthClient::HandleGatewayPendingTicket(const nlohmann::json &j) {
+    RemoteAuthPendingTicketMessage msg = j;
+
+    const auto encrypted_payload = Glib::Base64::decode(msg.EncryptedUserPayload);
+    const auto payload = Decrypt(reinterpret_cast<const unsigned char *>(encrypted_payload.data()), encrypted_payload.size());
+
+    m_log->trace("User payload: {}", std::string(payload.begin(), payload.end()));
+}
+
+void RemoteAuthClient::Init() {
+    RemoteAuthInitMessage msg;
+
+    GenerateKey();
+    msg.EncodedPublicKey = GetEncodedPublicKey();
+    if (msg.EncodedPublicKey.empty()) {
+        m_log->error("Something went wrong");
+        // todo disconnect
+        return;
+    }
+
+    m_ws.Send(msg);
+}
+
+void RemoteAuthClient::GenerateKey() {
+    // you javascript people have it so easy
+    // check out this documentation https://www.openssl.org/docs/man1.1.1/man3/PEM_write_bio_PUBKEY.html
+
+    m_pkey_ctx.reset(EVP_PKEY_CTX_new_id(EVP_PKEY_RSA, nullptr));
+    if (!m_pkey_ctx) {
+        m_log->error("Failed to create RSA context");
+        return;
+    }
+
+    if (EVP_PKEY_keygen_init(m_pkey_ctx.get()) <= 0) {
+        m_log->error("Failed to initialize RSA context");
+        return;
+    }
+
+    if (EVP_PKEY_CTX_set_rsa_keygen_bits(m_pkey_ctx.get(), 2048) <= 0) {
+        m_log->error("Failed to set keygen bits");
+        return;
+    }
+
+    EVP_PKEY *pkey_tmp = nullptr;
+    if (EVP_PKEY_keygen(m_pkey_ctx.get(), &pkey_tmp) <= 0) {
+        m_log->error("Failed to generate keypair");
+        return;
+    }
+    m_pkey.reset(pkey_tmp);
+
+    m_dec_ctx.reset(EVP_PKEY_CTX_new(m_pkey.get(), nullptr));
+    if (EVP_PKEY_decrypt_init(m_dec_ctx.get()) <= 0) {
+        m_log->error("Failed to initialize RSA decrypt context");
+        return;
+    }
+
+    if (EVP_PKEY_CTX_set_rsa_padding(m_dec_ctx.get(), RSA_PKCS1_OAEP_PADDING) <= 0) {
+        m_log->error("EVP_PKEY_CTX_set_rsa_padding failed");
+        return;
+    }
+
+    if (EVP_PKEY_CTX_set_rsa_oaep_md(m_dec_ctx.get(), EVP_sha256()) <= 0) {
+        m_log->error("EVP_PKEY_CTX_set_rsa_oaep_md failed");
+        return;
+    }
+
+    if (EVP_PKEY_CTX_set_rsa_mgf1_md(m_dec_ctx.get(), EVP_sha256()) <= 0) {
+        m_log->error("EVP_PKEY_CTX_set_rsa_mgf1_md");
+        return;
+    }
+}
+
+std::string RemoteAuthClient::GetEncodedPublicKey() const {
+    auto bio = BIO_ptr(BIO_new(BIO_s_mem()), BIO_free);
+    if (!bio) {
+        m_log->error("Failed to create BIO");
+        return {};
+    }
+
+    if (PEM_write_bio_PUBKEY(bio.get(), m_pkey.get()) <= 0) {
+        m_log->error("Failed to write public key to BIO");
+        return {};
+    }
+
+    // i think this is freed when the bio is too
+    BUF_MEM *mem = nullptr;
+    if (BIO_get_mem_ptr(bio.get(), &mem) <= 0) {
+        m_log->error("Failed to get BIO mem buf");
+        return {};
+    }
+
+    if (mem->data == nullptr || mem->length == 0) {
+        m_log->error("BIO mem buf is null or of zero length");
+        return {};
+    }
+
+    std::string pem_pubkey(mem->data, mem->length);
+    // isolate key
+    pem_pubkey.erase(0, pem_pubkey.find("\n") + 1);
+    pem_pubkey.erase(pem_pubkey.rfind("\n-"));
+    size_t pos;
+    while ((pos = pem_pubkey.find("\n")) != std::string::npos) {
+        pem_pubkey.erase(pos, 1);
+    }
+    return pem_pubkey;
+}
+
+std::vector<uint8_t> RemoteAuthClient::Decrypt(const unsigned char *in, size_t inlen) const {
+    // get length
+    size_t outlen;
+    if (EVP_PKEY_decrypt(m_dec_ctx.get(), nullptr, &outlen, in, inlen) <= 0) {
+        m_log->error("Failed to get length when decrypting");
+        return {};
+    }
+
+    std::vector<uint8_t> ret(outlen);
+    if (EVP_PKEY_decrypt(m_dec_ctx.get(), ret.data(), &outlen, in, inlen) <= 0) {
+        m_log->error("Failed to decrypt");
+        return {};
+    }
+    ret.resize(outlen);
+    return ret;
+}
+
+void RemoteAuthClient::OnWebsocketOpen() {
+    m_log->info("Websocket opened");
+}
+
+void RemoteAuthClient::OnWebsocketClose(const ix::WebSocketCloseInfo &info) {
+    if (info.remote) {
+        m_log->debug("Websocket closed (remote): {} ({})", info.code, info.reason);
+    } else {
+        m_log->debug("Websocket closed (local): {} ({})", info.code, info.reason);
+    }
+}
+
+void RemoteAuthClient::OnWebsocketMessage(const std::string &data) {
+    m_dispatch_mutex.lock();
+    m_dispatch_queue.push(data);
+    m_dispatcher.emit();
+    m_dispatch_mutex.unlock();
+}
+
+void RemoteAuthClient::HeartbeatThread() {
+    while (true) {
+        if (!m_heartbeat_waiter.wait_for(std::chrono::milliseconds(m_heartbeat_msec))) break;
+
+        m_ws.Send(RemoteAuthHeartbeatMessage());
+    }
+}
+
+void RemoteAuthClient::OnDispatch() {
+    m_dispatch_mutex.lock();
+    if (m_dispatch_queue.empty()) {
+        m_dispatch_mutex.unlock();
+        return;
+    }
+    auto msg = std::move(m_dispatch_queue.front());
+    m_dispatch_queue.pop();
+    m_dispatch_mutex.unlock();
+    OnGatewayMessage(msg);
+}
+
+RemoteAuthClient::type_signal_fingerprint RemoteAuthClient::signal_fingerprint() {
+    return m_signal_fingerprint;
+}