Disconnect all users if too many connection requests are received for It2Me

remoting/host/it2me/it2me_host.cc

Index: remoting/host/it2me/it2me_host.cc
diff --git a/remoting/host/it2me/it2me_host.cc b/remoting/host/it2me/it2me_host.cc
index f95c7aae786491f42cc30b9c07d952675c41a0a5..e4b6be323ca73bb1893679df12fee22bdac4d367 100644
--- a/remoting/host/it2me/it2me_host.cc
+++ b/remoting/host/it2me/it2me_host.cc
@@ -376,7 +376,7 @@ void It2MeHost::UpdateClientDomainPolicy(const std::string& client_domain) {
 
   VLOG(2) << "UpdateClientDomainPolicy: " << client_domain;
 
-  // When setting a client  domain policy, disconnect any existing session.
+  // When setting a client domain policy, disconnect any existing session.
   if (!client_domain.empty() && IsRunning()) {
     DisconnectOnNetworkThread();
   }
@@ -490,16 +490,14 @@ void It2MeHost::ValidateConnectionDetails(
   if (!SplitJidResource(remote_jid, &client_username, /*resource=*/nullptr)) {
     LOG(ERROR) << "Rejecting incoming connection from " << remote_jid
                << ": Invalid JID.";
-    result_callback.Run(
-        protocol::ValidatingAuthenticator::Result::ERROR_INVALID_ACCOUNT);
+    result_callback.Run(ValidationResult::ERROR_INVALID_ACCOUNT);
     DisconnectOnNetworkThread();
     return;
   }
 
   if (client_username.empty()) {
     LOG(ERROR) << "Invalid user name passed in: " << remote_jid;
-    result_callback.Run(
-        protocol::ValidatingAuthenticator::Result::ERROR_INVALID_ACCOUNT);
+    result_callback.Run(ValidationResult::ERROR_INVALID_ACCOUNT);
     DisconnectOnNetworkThread();
     return;
   }
@@ -517,6 +515,15 @@ void It2MeHost::ValidateConnectionDetails(
     }
   }
 
+  // If we receive valid connection details multiple times, then we don't know
+  // which remote user (if either) is valid so disconnect everyone.
+  if (state_ != kReceivedAccessCode) {

[Sergey Ulanov, 2017/03/02 23:07:29]

I don't think we want to shutdown the host when the user mistypes access code.
Currently the host keeps running and client can correct access code and try
connecting again. I'd like to keep this behavior.

Currently ValidatingAuthenticator calls validation callback before processing
the first message. Can it be updated to perform validation after base
authentication is complete? I think it should be enough to fix this bug.

[joedow, 2017/03/13 23:26:57]

I missed that scenario so thanks for pointing that out.  I've broken validation
into two steps, one which is run on incoming connections to weed out obviously
wrong ones before doing additional validation and a second step which occurs
after the lower level authenticators have all succeeded.  This second step is
the right place for the confirmation dialog as the JID has been validated, a
connection method has been negotiated, and we know the access code is valid.

+    LOG(ERROR) << "Received too many connection requests.";
+    result_callback.Run(ValidationResult::ERROR_TOO_MANY_CONNECTIONS);
+    DisconnectOnNetworkThread();
+    return;
+  }
+
   HOST_LOG << "Client " << client_username << " connecting.";
   SetState(kConnecting, std::string());