CertificateValidationCallback not called for websocket client

[andnig]

Hi,

first of all, thanks for the great project. I have just one problem: When using your websocket managed client, the CertificateValidationCallback seems not the be called. However, if I use the TCP client, anything works as expected. Any hints what I'm doing

               mqttInternalClientOptions = mqttInternalClientOptions
                .WithTls(new MqttClientOptionsBuilderTlsParameters()
                {
                    SslProtocol = sslVersion,
                    UseTls = true,
                    AllowUntrustedCertificates = false,
                    Certificates = new List<byte[]> { certBinary },
                    CertificateValidationCallback = (certificate, chain, sslPolicyErrors, arg4) =>
                    {
// some magic here
                        return isValid;
                    },
                })
                .WithProtocolVersion(mqttVersion)
                .WithCleanSession()
                .WithClientId(this.clientId);

           this.mqttClientOptions = new ManagedMqttClientOptionsBuilder()
                .WithAutoReconnectDelay(TimeSpan.FromSeconds(timeoutdelay))
                .WithMaxPendingMessages(this.mqttConfiguration.MaxReconnectBuffer)
                .WithPendingMessagesOverflowStrategy(this.mqttConfiguration.DropOldestIfOverflow
                    ? MqttPendingMessagesOverflowStrategy.DropOldestQueuedMessage
                    : MqttPendingMessagesOverflowStrategy.DropNewMessage)
                .WithStorage(clientRetainedMessageHandler)
                .WithClientOptions(mqttInternalClientOptions.Build())
                .Build();
 

Thanks in advance for any input!

[andnig]

Ok, I can answer my own question. ClientWebsocket for netstandard2.0 does not provide CertificateValidationCallback. Had to upgrade the lib to netcoreapp2.1 to get it done.

[andnig]

I'd like to reopen this issue, as the ClientWebsocketOptions for .netstandard2.1 now provides support for setting RemoteCertificateValidationCallback. Any chance you guys can add this to the MqttWebsocketChannel.cs as soon as you upgrade to .netstandard2.1?

https://docs.microsoft.com/en-us/dotnet/api/system.net.websockets.clientwebsocketoptions.remotecertificatevalidationcallback?view=netcore-3.1

In the ConnectAsync-Method, something like the following would enable this new feature. if (_options.TlsOptions?.UseTls == true) { clientWebSocket.Options.RemoteCertificateValidationCallback = new System.Net.Security.RemoteCertificateValidationCallback((a,b,c,d) => { return _options.TlsOptions.CertificateValidationCallback(b, c, d, null); }); }

[andnig]

Hey guys, any chance you are adding netstandard2.1 and allowing to somehow access RemoteCertificateValidationCallback in the ClientWebsocketOptions?

[chkr1011]

Hi, I added support for this in master branch. It will be released with 3.0.10. Please let me know if this works for you. It requires to use the new validation handler. The validation callback will be removed in the future.

[andnig]

Hey, thanks for that. Seems to work for me 👍 Looking forward to the release and thanks for your great work!

[andnig]

Hey @chkr1011 Do you have a rough schedule for the release of current master branch? I have to think whether I fork the project now and create a private nuget or whether I can wait for your release.

Thanks for the update :-)

[chkr1011]

I can give you a beta build within the next couple of days.

[andnig]

That would be great. Thanks a lot 👍