Resolved Issues with a TLS connection, Google has nearly nothing on my error: UNITYTLS_INVALID_ARGUMENT

Greetings friends,

I'm having issues with a secure connection to a third-party service. Their SDK was written for C#, but not necessarily for Unity, and I'm trying to port it over. The issue happens after I have validated the certificate and established an SSLStream. Here is the error I get:

Code (CSharp):

1. Exception: System.Security.Authentication.AuthenticationException: A call to SSPI failed, see inner exception. ---> Mono.Security.Interface.TlsException: Failed to read data to TLS context - error code: UNITYTLS_INVALID_ARGUMENT

Searching for this yields a bunch of stuff related to old versions of Unity not supporting TLS 1.2, and those errors are different than the one above. This page seems to indicate that some argument is null or otherwise invalid, but I don't know what is actually causing this error. I get a callback from their SDK telling me the error happened and the exception, and that's about it. The connection code is running on a separate thread, and it happens after I log that I'm sending them a request and before I log that I got a valid response.

I am in contact with the developers of the SDK and attempting to resolve the issue, but the reality is that their SDK doesn't officially support Unity (yet), and I'm trying to jam a square peg in a round hole. Has anyone ever seen this error before, and if so, what might be some possible causes aside from what I already know?

For what it's worth, I can connect to their servers using an insecure connection, but this is not viable for the production version of the application.

Cheers,
- Dusty

 

Did you try hit this endpoint and see if your TLS is airtight?

https://www.sslshopper.com/ssl-checker.html

Last time I had a weird Android network error, turns out the website itself had some obtuse certificate signing trust error.

 

Good thought. I just checked it, and it looks like we are all good on that end.

 

Ok, so I figured out what code is actually causing the exception. The code is this:

Code (CSharp):

1. await Input.ReadAsync(Array.Empty<byte>(), 0, 0);

Where Input is the Stream coming in. This optimization is basically saying to wait to read from the stream until there is data on it. It seems Unity doesn't appreciate this for some reason. I can "solve" the problem by removing this optimization and just always reading from the stream at some performance cost. My intention is to file a bug report on this, as that's a pretty common optimization and it really should work.

 

What portion of the above interacts with Unity? There are very strict rules as far as "await" and the main thread as far as Unity goes, but unless

Input

above is the Unity Input Manager (I assume it's actually a stream?), that shouldn't matter.

 

The above code doesn't really interact with Unity. This code is in the third party SDK and is running on it's own thread. I believe the exception came from the Unity fork of the mono runtime. When information comes back on the Stream, I store it if I need it to then be used on the main thread later.

 

Case 1316968

 

As this bug ever been fixed?

I also have a 3rd party component (Telepathy V1.8) that cause an issue if I replace the networkstream by a sslstream