Install certificates in to the Windows Local user certificate store in C#

Question

I'm writing a Windows service that needs several certificates in the certificate store in order to connect to a third party web service.

On my installer I call a small application (C#) that creates a user to run the service as.

It works fine.

I now need to install about 10 certificates (don't ask!) into the users certificate store, but can't find any succinct programmatic way to do so.

Any hints? Or am I going to have to use COM interop...

Answer 1

Turns out you first need to impersonate the user.

Using the very nice library described in A small C# Class for impersonating a User, you can do the following:

using (new Impersonator("username", "", "password"))
{
    try
    {
        X509Store serviceRuntimeUserCertificateStore = new X509Store(StoreName.My);
        string baseDir = AppDomain.CurrentDomain.BaseDirectory;
        string certPath = Path.Combine(baseDir, certificateFolder);

        string certificateFile = "c:\\file.cert";
        string certificatePassword = "somePassword";
        string certificateLocation = certPath + "\\" + certificateFile;

        InstallCertificate(certificateLocation, certificatePassword);
    }
    catch (Exception ex)
    {
        Console.WriteLine(ex);
    }
}

private static void InstallCertificate(string certificatePath, string certificatePassword)
{
    try
    {
        var serviceRuntimeUserCertificateStore = new X509Store(StoreName.My);
        serviceRuntimeUserCertificateStore.Open(OpenFlags.ReadWrite);

        X509Certificate2 cert;

        try
        {
            cert = new X509Certificate2(certificatePath, certificatePassword);
        }
        catch(Exception ex)
        {
            Console.WriteLine("Failed to load certificate " + certificatePath);
            throw new DataException("Certificate appeared to load successfully but also seems to be null.", ex);
        }

        serviceRuntimeUserCertificateStore.Add(cert);
        serviceRuntimeUserCertificateStore.Close();
    }
    catch(Exception)
    {
        Console.WriteLine("Failed to install {0}.  Check the certificate index entry and verify the certificate file exists.", certificatePath);
    }
}

Please add your own exception handling. If you're adding multiple certificates keep the X509Store open for the duration for efficiency.