LibTLS: Avoid busy-wait between ClientHello and ServerHello

This commit also adds a timeout timer to cancel the connection if the
server does not respond to the hello request in 10 seconds.

Libraries/LibTLS/ClientHandshake.cpp

@@ -238,6 +238,16 @@ ssize_t TLSv12::handle_finished(const ByteBuffer& buffer, WritePacketStage& writ
 #endif
     m_context.connection_status = ConnectionStatus::Established;
 
+    if (m_handshake_timeout_timer) {
+        // Disable the handshake timeout timer as handshake has been established.
+        m_handshake_timeout_timer->stop();
+        m_handshake_timeout_timer->remove_from_parent();
+        m_handshake_timeout_timer = nullptr;
+    }
+
+    if (on_tls_ready_to_write)
+        on_tls_ready_to_write(*this);
+
     return handle_message(buffer);
 }
 

Libraries/LibTLS/Handshake.cpp

@@ -167,4 +167,11 @@ ByteBuffer TLSv12::build_finished()
     return packet;
 }
 
+void TLSv12::alert(AlertLevel level, AlertDescription code)
+{
+    auto the_alert = build_alert(level == AlertLevel::Critical, (u8)code);
+    write_packet(the_alert);
+    flush();
+}
+
 }

Libraries/LibTLS/Record.cpp

@@ -311,9 +311,7 @@ ssize_t TLSv12::handle_message(const ByteBuffer& buffer)
             if (code == 0) {
                 // close notify
                 res += 2;
-                auto closure_alert = build_alert(true, (u8)AlertDescription::CloseNotify);
+                alert(AlertLevel::Critical, AlertDescription::CloseNotify);
-                write_packet(closure_alert);
-                flush();
                 m_context.connection_finished = true;
             }
             m_context.error_code = (Error)code;

Libraries/LibTLS/Socket.cpp

@@ -24,6 +24,7 @@
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
+#include <LibCore/DateTime.h>
 #include <LibCore/Timer.h>
 #include <LibCrypto/ASN1/DER.h>
 #include <LibCrypto/PK/Code/EMSA_PSS.h>
@@ -110,14 +111,32 @@ bool TLSv12::common_connect(const struct sockaddr* saddr, socklen_t length)
         }
     }
 
-    auto packet = build_hello();
-    write_packet(packet);
-
     Core::Socket::on_connected = [this] {
         Core::Socket::on_ready_to_read = [this] {
             read_from_socket();
         };
-        write_into_socket();
+
+        auto packet = build_hello();
+        write_packet(packet);
+
+        deferred_invoke([&](auto&) {
+            m_handshake_timeout_timer = Core::Timer::create_single_shot(
+                m_max_wait_time_for_handshake_in_seconds * 1000, [&] {
+                    // The server did not respond fast enough,
+                    // time the connection out.
+                    alert(AlertLevel::Critical, AlertDescription::UserCanceled);
+                    m_context.connection_finished = true;
+                    m_context.tls_buffer.clear();
+                    m_context.error_code = Error::TimedOut;
+                    m_context.critical_error = (u8)Error::TimedOut;
+                    check_connection_state(false); // Notify the client.
+                },
+                this);
+            write_into_socket();
+            m_handshake_timeout_timer->start();
+        });
+        m_has_scheduled_write_flush = true;
+
         if (on_tls_connected)
             on_tls_connected();
     };
@@ -138,7 +157,7 @@ void TLSv12::read_from_socket()
 
     if (!check_connection_state(true))
         return;
-    flush();
+
     consume(Core::Socket::read(4096));
 }
 
@@ -152,13 +171,10 @@ void TLSv12::write_into_socket()
         return;
     flush();
 
-    if (!is_established()) {
+    if (!is_established())
-        deferred_invoke([this](auto&) { write_into_socket(); });
-        m_has_scheduled_write_flush = true;
         return;
-    }
 
-    if (is_established() && !m_context.application_buffer.size()) // hey client, you still have stuff to read...
+    if (!m_context.application_buffer.size()) // hey client, you still have stuff to read...
         if (on_tls_ready_to_write)
             on_tls_ready_to_write(*this);
 }

Libraries/LibTLS/TLSv12.h

@@ -142,6 +142,7 @@ enum class Error : i8 {
     FeatureNotSupported = -17,
     DecryptionFailed = -20,
     NeedMoreData = -21,
+    TimedOut = -22,
 };
 
 enum class AlertLevel : u8 {
@@ -293,6 +294,8 @@ struct Context {
     StringView negotiated_alpn;
 
     size_t send_retries { 0 };
+
+    time_t handshake_initiation_timestamp { 0 };
 };
 
 class TLSv12 : public Core::Socket {
@@ -335,7 +338,7 @@ public:
     ByteBuffer read(size_t max_size);
 
     bool write(const ByteBuffer& buffer);
-    void alert(bool critical, u8 code);
+    void alert(AlertLevel, AlertDescription);
 
     bool can_read_line() const { return m_context.application_buffer.size() && memchr(m_context.application_buffer.data(), '\n', m_context.application_buffer.size()); }
     bool can_read() const { return m_context.application_buffer.size() > 0; }
@@ -467,7 +470,10 @@ private:
     OwnPtr<Crypto::Cipher::AESCipher::CBCMode> m_aes_local;
     OwnPtr<Crypto::Cipher::AESCipher::CBCMode> m_aes_remote;
 
-    bool m_has_scheduled_write_flush = false;
+    bool m_has_scheduled_write_flush { false };
+    i32 m_max_wait_time_for_handshake_in_seconds { 10 };
+
+    RefPtr<Core::Timer> m_handshake_timeout_timer;
 };
 
 namespace Constants {