Mono https webrequest fails with “The authenticati

Question

I'm making a simple REST client to use in my C# applications. In .net on Windows It works great with http:// and https:// connections. In mono 2.6.7 (Also tested with 2.8 with the same results) on Ubuntu 10.10 only http:// works. https:// connections throw up this exception on the request.GetResponse() method:

Unhandled Exception: System.Net.WebException: Error getting response stream (Write: The authentication or decryption has failed.): SendFailure ---> System.IO.IOException: The authentication or decryption has failed. ---> Mono.Security.Protocol.Tls.TlsException: Invalid certificate received from server. Error code: 0xffffffff800b010a
  at Mono.Security.Protocol.Tls.Handshake.Client.TlsServerCertificate.validateCertificates (Mono.Security.X509.X509CertificateCollection certificates) [0x00000] in <filename unknown>:0 
  at Mono.Security.Protocol.Tls.Handshake.Client.TlsServerCertificate.ProcessAsTls1 () [0x00000] in <filename unknown>:0 
  at Mono.Security.Protocol.Tls.Handshake.HandshakeMessage.Process () [0x00000] in <filename unknown>:0 
  at (wrapper remoting-invoke-with-check) Mono.Security.Protocol.Tls.Handshake.HandshakeMessage:Process ()
  at Mono.Security.Protocol.Tls.ClientRecordProtocol.ProcessHandshakeMessage (Mono.Security.Protocol.Tls.TlsStream handMsg) [0x00000] in <filename unknown>:0 
  at Mono.Security.Protocol.Tls.RecordProtocol.InternalReceiveRecordCallback (IAsyncResult asyncResult) [0x00000] in <filename unknown>:0 
  --- End of inner exception stack trace ---
  at Mono.Security.Protocol.Tls.SslStreamBase.AsyncHandshakeCallback (IAsyncResult asyncResult) [0x00000] in <filename unknown>:0 
  --- End of inner exception stack trace ---
  at System.Net.HttpWebRequest.EndGetResponse (IAsyncResult asyncResult) [0x00000] in <filename unknown>:0 
  at System.Net.HttpWebRequest.GetResponse () [0x00000] in <filename unknown>:0 

I haven't been able to find any way to fix this. Anyone have any idea why this is happening and how to fix it?

Again, this only fails in Mono, .Net doesn't seem to have any problem establishing a connection.

here's the calling code:

public JToken DoRequest(string path, params string[] parameters) {
    if(!path.StartsWith("/")) {
        path = "/" + path;
    }
    string fullUrl = url + path + ToQueryString(parameters);

    if(DebugUrls) Console.WriteLine("Requesting: {0}", fullUrl);

    WebRequest request = HttpWebRequest.CreateDefault(new Uri(fullUrl));
    using(WebResponse response = request.GetResponse())
    using(Stream responseStream = response.GetResponseStream()) {
        return ReadResponse(responseStream);
    }
}

Answer 1

Mono does not trust any certificate by default, to import the Mozilla trusted root authorities you can run mozroots --import --quiet in the mono installation folder where mozroots.exe is located

Answer 2

I had the same problem with Unity (which also uses mono) and this post helped me to solve it.

Just add the following line before making your request:

ServicePointManager.ServerCertificateValidationCallback = MyRemoteCertificateValidationCallback;

And this method:

public bool MyRemoteCertificateValidationCallback(System.Object sender,
    X509Certificate certificate, X509Chain chain, SslPolicyErrors sslPolicyErrors)
{
    bool isOk = true;
    // If there are errors in the certificate chain,
    // look at each error to determine the cause.
    if (sslPolicyErrors != SslPolicyErrors.None) {
        for (int i=0; i<chain.ChainStatus.Length; i++) {
            if (chain.ChainStatus[i].Status == X509ChainStatusFlags.RevocationStatusUnknown) {
                continue;
            }
            chain.ChainPolicy.RevocationFlag = X509RevocationFlag.EntireChain;
            chain.ChainPolicy.RevocationMode = X509RevocationMode.Online;
            chain.ChainPolicy.UrlRetrievalTimeout = new TimeSpan (0, 1, 0);
            chain.ChainPolicy.VerificationFlags = X509VerificationFlags.AllFlags;
            bool chainIsValid = chain.Build ((X509Certificate2)certificate);
            if (!chainIsValid) {
                isOk = false;
                break;
            }
        }
    }
    return isOk;
}

Answer 3

The first answer says it already: Mono on anything other than Windows doesn’t come with anything so initially it doesn’t trust any certificate. So what to do?

Here is a nice article about different ways to deal with the problem from the developer’s perspective: http://www.mono-project.com/archived/usingtrustedrootsrespectfully/

Short summary: You can either:

• ignore the security concern
• ignore the problem
• let the user know and abort
• let the user know and give him/her a choice to continue at own risk

The above link comes with code examples for each case.

Answer 4

I was still having this problem after importing the certificates as per the accepted answer.

I found that support for TLS 1.2 was added in Mono 4.8.0 which uses Google's BoringSSL, and that I was using a version of Mono older than this. I updated to Mono 5.10 and can now connect without receiving this exception.

Answer 5

I had the same problem. When the http response throws this exception then I do:

System.Diagnostics.Process.Start("mozroots","--import --quiet");

this imports the missing certificates and the exception never happend again.

Answer 6

The .NET Framework on Windows uses the Windows Certificates store (mmc, Add/Remove Snap-Ins, Certificates) to determine whether to accept an SSL certificate from a remote site. Windows ships with a bunch of Root and Intermediate Certificate Authorities (CA) and they get updated periodically by Windows Update. As a result, your .NET code will generally trust a certificate provided it was issued by a CA or a descendant of a CA in the certificate store (most reputable commercial CA's are included).

In Mono, there is no Windows Certificate store. Mono has it's own store. By default, it is empty (there are no default CA's that are trusted). You need to manage the entries yourself.

Take a look here:

• http://www.mono-project.com/FAQ:_Security
• https://raw.github.com/mono/mono/master/mcs/class/Mono.Security/Test/tools/tlstest/tlstest.cs

The mozroots.exe point will cause your mono install to trust everything that Firefox trusts after a default install.