c# - Mono HttpListener client certificate

Question

I have created a server using HttpListener. It works perfect without SSL, but with SSL something strange happens.

I have installed the certificate using httpcfg and even with my own program, it installs correctly, the listener starts and serves HTTPS requests, but always asks for a client certificate.

It does not happens on Windows/.net, only with Linux/mono (I'm using ver 3.4.0) and is very annoying, I don't want the user to be asked each time he tries to log in for a client certificate.

Is this a mono bug or is there any way to disable the client certificate negotiation?

Thanks.

Answer 1

I'm having the same problem. What I've discovered is that this is hardcoded in Mono. In mcs/class/System/System.Net/HttpConnection.cs, when the constructor of SslServerStream is called, you will notice that the requestClientCertificate is hardcoded to true.

I came across this PR that attempts to change this hardcoded value to false, however it's currently semi-rejected due to "I rather not change one hardcoded value for another hardcoded value."

[Update] And I just now realized you (OP) are the author of the PR :)

[Update 9/21/2016] It looks like this question is still getting hits. If it is helpful to anyone, we went with nginx as a reverse proxy a long time ago when we could not resolve this issue. I'm glad we did, and should have done it sooner. It is much faster than Mono for handling the SSL/TLS, and allows us to more carefully control the crypto suites and keep up to date with security patches.

I'm keeping an eye on Mono 4.6, which has yet to release. With their overhaul of TLS and the ability to plug in alternate implementations at runtime this might give us a path forward without using nginx reverse proxy.