Register certificate to SSL port

Question

I have a windows service (running as LocalSystem) that is self-hosting an OWIN service (SignalR) and needs to be accessed over SSL.

I can set up the SSL binding on my local development machine just fine - and I can access my service over SSL on that same machine. However, when I go to another machine and try to run the following command I receive an error:

Command:

netsh http add sslcert ipport=0.0.0.0:9389 appid={...guid here...} certhash=...cert hash here...

Error:

SSL Certificate add failed, Error: 1312

A specified logon session does not exist. It may have already been terminated.

The certificate I am using is a fully signed cert (not a development cert) and works on my local dev box. Here's what I am doing:

Windows service starts up and registers my certificate using the following code:

var store = new X509Store(StoreName.Root, StoreLocation.LocalMachine);
store.Open(OpenFlags.ReadWrite);
var path = AppDomain.CurrentDomain.BaseDirectory;
var cert = new X509Certificate2(path + @"\mycert.cer");
var existingCert = store.Certificates.Find(X509FindType.FindByThumbprint, cert.Thumbprint, false);
if (existingCert.Count == 0)
    store.Add(cert);
store.Close();

I then attempt to bind the certificate to port 9389 using netsh and the following code:

var process = new Process {
    StartInfo = new ProcessStartInfo {
        WindowStyle = ProcessWindowStyle.Hidden,
        FileName = "cmd.exe",
        Arguments = "/c netsh http add sslcert ipport=0.0.0.0:9389 appid={12345678-db90-4b66-8b01-88f7af2e36bf} certhash=" + cert.thumbprint
    }
};
process.Start();

The code above successfully installs the certificate to the "Local Machine - Certificates\Trusted Root Certification Authorities\Certificates" certificate folder - but the netsh command fails to run with the error I described above. If I take the netsh command and run it in a command prompt as an administrator on that box it also throws out the same error - so I don't believe that it's a code related issue...

I have to imagine that this is possible to accomplish - plenty of other applications create self-hosted services and host them over ssl - but I cannot seem to get this to work at all...anyone have any suggestions? Perhaps programmatic alternatives to netsh?

Answer 1

Okay I found the answer:

If you are bringing in a certificate from another machine it will NOT work on the new machine. You have to create a self-signed certificate on the new machine and import it into the Local Computer's Trusted Root Certificates.

The answer is from here: How to create a self-signed certificate using C#?

For posterity's sake this is the process used to create a self signed cert (from the above referenced answer):

Import the CertEnroll 1.0 Type Library from the COM tab in your project's references

Add the following method to your code:

//This method credit belongs to this StackOverflow Answer:
//https://stackoverflow.com/a/13806300/594354
using CERTENROLLLib;

public static X509Certificate2 CreateSelfSignedCertificate(string subjectName)
{
    // create DN for subject and issuer
    var dn = new CX500DistinguishedName();
    dn.Encode("CN=" + subjectName, X500NameFlags.XCN_CERT_NAME_STR_NONE);

    // create a new private key for the certificate
    CX509PrivateKey privateKey = new CX509PrivateKey();
    privateKey.ProviderName = "Microsoft Base Cryptographic Provider v1.0";
    privateKey.MachineContext = true;
    privateKey.Length = 2048;
    privateKey.KeySpec = X509KeySpec.XCN_AT_SIGNATURE; // use is not limited
    privateKey.ExportPolicy = X509PrivateKeyExportFlags.XCN_NCRYPT_ALLOW_PLAINTEXT_EXPORT_FLAG;
    privateKey.Create();

    // Use the stronger SHA512 hashing algorithm
    var hashobj = new CObjectId();
    hashobj.InitializeFromAlgorithmName(ObjectIdGroupId.XCN_CRYPT_HASH_ALG_OID_GROUP_ID,
        ObjectIdPublicKeyFlags.XCN_CRYPT_OID_INFO_PUBKEY_ANY, 
        AlgorithmFlags.AlgorithmFlagsNone, "SHA512");

    // add extended key usage if you want - look at MSDN for a list of possible OIDs
    var oid = new CObjectId();
    oid.InitializeFromValue("1.3.6.1.5.5.7.3.1"); // SSL server
    var oidlist = new CObjectIds();
    oidlist.Add(oid);
    var eku = new CX509ExtensionEnhancedKeyUsage();
    eku.InitializeEncode(oidlist); 

    // Create the self signing request
    var cert = new CX509CertificateRequestCertificate();
    cert.InitializeFromPrivateKey(X509CertificateEnrollmentContext.ContextMachine, privateKey, "");
    cert.Subject = dn;
    cert.Issuer = dn; // the issuer and the subject are the same
    cert.NotBefore = DateTime.Now;
    // this cert expires immediately. Change to whatever makes sense for you
    cert.NotAfter = DateTime.Now; 
    cert.X509Extensions.Add((CX509Extension)eku); // add the EKU
    cert.HashAlgorithm = hashobj; // Specify the hashing algorithm
    cert.Encode(); // encode the certificate

    // Do the final enrollment process
    var enroll = new CX509Enrollment();
    enroll.InitializeFromRequest(cert); // load the certificate
    enroll.CertificateFriendlyName = subjectName; // Optional: add a friendly name
    string csr = enroll.CreateRequest(); // Output the request in base64
    // and install it back as the response
    enroll.InstallResponse(InstallResponseRestrictionFlags.AllowUntrustedCertificate,
        csr, EncodingType.XCN_CRYPT_STRING_BASE64, ""); // no password
    // output a base64 encoded PKCS#12 so we can import it back to the .Net security classes
    var base64encoded = enroll.CreatePFX("", // no password, this is for internal consumption
        PFXExportOptions.PFXExportChainWithRoot);

    // instantiate the target class with the PKCS#12 data (and the empty password)
    return new System.Security.Cryptography.X509Certificates.X509Certificate2(
        System.Convert.FromBase64String(base64encoded), "", 
        // mark the private key as exportable (this is usually what you want to do)
        System.Security.Cryptography.X509Certificates.X509KeyStorageFlags.Exportable
    );
}

For anyone else reading this answer - the code for importing the certificate from the original question should now change to the following:

var certName = "Your Cert Subject Name";
var store = new X509Store(StoreName.Root, StoreLocation.LocalMachine);
store.Open(OpenFlags.ReadWrite);
var existingCert = store.Certificates.Find(X509FindType.FindBySubjectName, certName, false);
if (existingCert.Count == 0)
{
    var cert = CreateSelfSignedCertificate(certName);
    store.Add(cert);
    RegisterCertForSSL(cert.Thumbprint);
}
store.Close();