Don't send Heartbeat messages when connection is unauthenticated

[mcktr]

Do not send Heartbeat messages when the connection is not authenticated.

Context

When a new JSON-RPC connection is established we start to sent heartbeat messages, even if the connection is not authenticated (e.g. certificate not signed). If the connection stalls for some reason and the answer to the heartbeat message is not received in time we disconnect the client.

icinga2/lib/remote/jsonrpcconnection-heartbeat.cpp

Lines 30 to 35 in 202e90b

	if (m_NextHeartbeat != 0 && m_NextHeartbeat < Utility::GetTime()) {
	Log(LogWarning, "JsonRpcConnection")
	<< "Client for endpoint '" << m_Endpoint->GetName() << "' has requested "
	<< "heartbeat message but hasn't responded in time. Closing connection.";
	Disconnect();

Problem

On unauthenticated connections we don't set the m_Endpoint variable, only when authenticated. In the log message from above we use m_Endpoint variable which will result in a crash.

icinga2/lib/remote/jsonrpcconnection.cpp

Lines 45 to 46 in 202e90b

	if (authenticated)
	m_Endpoint = Endpoint::GetByName(identity);

I think it is not necessary to send heartbeat messages on unauthenticated connections. But I may not see the full scope here. I'll leave this PR as draft and maybe @dnsmichi and @Al2Klimov can have a look? :-)

This may have an influence on #7569 and #7687.

[dnsmichi]

I'm not sure about the impact here, we'll have to investigate. I know where you're coming from, but applying this change just hides the crash and leak within the JSON messaging backend.

[Al2Klimov]

I'd prefer #7747.

[dnsmichi]

I'm going with #7747 as well, if you don't mind @mcktr

[mcktr]

I also opt for #7747, closing here.