Merge pull request #6813 from Icinga/feature/gelfwriter-tls-support

 Implement TLS support for the GelfWriter feature

doc/09-object-types.md

@@ -1344,7 +1344,10 @@ Configuration Attributes:
   source                    | String                | **Optional.** Source name for this instance. Defaults to `icinga2`.
   enable\_send\_perfdata    | Boolean               | **Optional.** Enable performance data for 'CHECK RESULT' events.
   enable\_ha                | Boolean               | **Optional.** Enable the high availability functionality. Only valid in a [cluster setup](06-distributed-monitoring.md#distributed-monitoring-high-availability-features). Defaults to `false`.
-
+  enable\_tls               | Boolean               | **Optional.** Whether to use a TLS stream. Defaults to `false`.
+  ca\_path                  | String                | **Optional.** Path to CA certificate to validate the remote host. Requires `enable_tls` set to `true`.
+  cert\_path                | String                | **Optional.** Path to host certificate to present to the remote host for mutual verification. Requires `enable_tls` set to `true`.
+  key\_path                 | String                | **Optional.** Path to host key to accompany the cert\_path. Requires `enable_tls` set to `true`.
 
 ### GraphiteWriter <a id="objecttype-graphitewriter"></a>
 

lib/perfdata/gelfwriter.cpp

@@ -22,6 +22,11 @@
 #include "base/statsfunction.hpp"
 #include <boost/algorithm/string/replace.hpp>
 #include <utility>
+#include "base/io-engine.hpp"
+#include <boost/asio/write.hpp>
+#include <boost/asio/buffer.hpp>
+#include <boost/system/error_code.hpp>
+#include <boost/asio/error.hpp>
 
 using namespace icinga;
 
@@ -126,11 +131,7 @@ void GelfWriter::ExceptionHandler(boost::exception_ptr exp)
 	Log(LogDebug, "GelfWriter")
 		<< "Exception during Graylog Gelf operation: " << DiagnosticInformation(std::move(exp));
 
-	if (GetConnected()) {
-		m_Stream->Close();
-
-		SetConnected(false);
-	}
+	DisconnectInternal();
 }
 
 void GelfWriter::Reconnect()
@@ -156,20 +157,46 @@ void GelfWriter::ReconnectInternal()
 	if (GetConnected())
 		return;
 
-	TcpSocket::Ptr socket = new TcpSocket();
-
 	Log(LogNotice, "GelfWriter")
 		<< "Reconnecting to Graylog Gelf on host '" << GetHost() << "' port '" << GetPort() << "'.";
 
+	bool ssl = GetEnableTls();
+
+	if (ssl) {
+		std::shared_ptr<boost::asio::ssl::context> sslContext;
+
+		try {
+			sslContext = MakeAsioSslContext(GetCertPath(), GetKeyPath(), GetCaPath());
+		} catch (const std::exception& ex) {
+			Log(LogWarning, "GelfWriter")
+				<< "Unable to create SSL context.";
+			throw;
+		}
+
+		m_Stream.first = std::make_shared<AsioTlsStream>(IoEngine::Get().GetIoService(), *sslContext, GetHost());
+	} else {
+		m_Stream.second = std::make_shared<AsioTcpStream>(IoEngine::Get().GetIoService());
+	}
+
 	try {
-		socket->Connect(GetHost(), GetPort());
+		icinga::Connect(ssl ? m_Stream.first->lowest_layer() : m_Stream.second->lowest_layer(), GetHost(), GetPort());
 	} catch (const std::exception& ex) {
-		Log(LogCritical, "GelfWriter")
-			<< "Can't connect to Graylog Gelf on host '" << GetHost() << "' port '" << GetPort() << "'.";
-		throw ex;
+		Log(LogWarning, "GelfWriter")
+			<< "Can't connect to Graylog Gelf on host '" << GetHost() << "' port '" << GetPort() << ".'";
+		throw;
 	}
 
-	m_Stream = new NetworkStream(socket);
+	if (ssl) {
+		auto& tlsStream (m_Stream.first->next_layer());
+
+		try {
+			tlsStream.handshake(tlsStream.client);
+		} catch (const std::exception& ex) {
+			Log(LogWarning, "GelfWriter")
+				<< "TLS handshake with host '" << GetHost() << " failed.'";
+			throw;
+		}
+	}
 
 	SetConnected(true);
 
@@ -194,9 +221,22 @@ void GelfWriter::DisconnectInternal()
 	if (!GetConnected())
 		return;
 
-	m_Stream->Close();
+	if (m_Stream.first) {
+		boost::system::error_code ec;
+		m_Stream.first->next_layer().shutdown(ec);
+
+		// https://stackoverflow.com/a/25703699
+		// As long as the error code's category is not an SSL category, then the protocol was securely shutdown
+		if (ec.category() == boost::asio::error::get_ssl_category()) {
+			Log(LogCritical, "GelfWriter")
+				<< "TLS shutdown with host '" << GetHost() << "' could not be done securely.";
+		}
+	} else if (m_Stream.second) {
+		m_Stream.second->close();
+	}
 
 	SetConnected(false);
+
 }
 
 void GelfWriter::CheckResultHandler(const Checkable::Ptr& checkable, const CheckResult::Ptr& cr)
@@ -456,7 +496,13 @@ void GelfWriter::SendLogMessage(const Checkable::Ptr& checkable, const String& g
 		Log(LogDebug, "GelfWriter")
 			<< "Checkable '" << checkable->GetName() << "' sending message '" << log << "'.";
 
-		m_Stream->Write(log.CStr(), log.GetLength());
+		if (m_Stream.first) {
+			boost::asio::write(*m_Stream.first, boost::asio::buffer(msgbuf.str()));
+			m_Stream.first->flush();
+		} else {
+			boost::asio::write(*m_Stream.second, boost::asio::buffer(msgbuf.str()));
+			m_Stream.second->flush();
+		}
 	} catch (const std::exception& ex) {
 		Log(LogCritical, "GelfWriter")
 			<< "Cannot write to TCP socket on host '" << GetHost() << "' port '" << GetPort() << "'.";

lib/perfdata/gelfwriter.hpp

@@ -33,7 +33,7 @@ class GelfWriter final : public ObjectImpl<GelfWriter>
 	void Pause() override;
 
 private:
-	Stream::Ptr m_Stream;
+	OptionalTlsStream m_Stream;
 	WorkQueue m_WorkQueue{10000000, 1};
 
 	Timer::Ptr m_ReconnectTimer;

lib/perfdata/gelfwriter.ti

@@ -31,6 +31,12 @@ class GelfWriter : ConfigObject
 	[config] bool enable_ha {
 		default {{{ return false; }}}
 	};
+    [config] bool enable_tls {
+        default {{{ return false; }}}
+    };
+    [config] String ca_path;
+    [config] String cert_path;
+    [config] String key_path;
 };
 
 }