SSH Authenticate using a Smart Card Private Key

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Demonstrates using a private key stored on an HSM (smart card or token) for SSH public-key authentication. A JSON template locates the private and public key objects by class, key type, and label, and the returned handles are bound to an SshKey object.

#include <CkPkcs11.h>
#include <CkJsonObject.h>
#include <CkSshKey.h>
#include <CkSsh.h>

void ChilkatSample(void)
    {
    bool success = false;

    //  This example requires the Chilkat API to have been previously unlocked.
    //  See Global Unlock Sample for sample code.

    //  Demonstrates using a private key stored on an HSM (smart card or token) for SSH public-key
    //  authentication.  Public-key authentication means the client uses the private key, while the
    //  corresponding public key is installed on the server under the SSH account.
    //  
    //  Note: Chilkat's PKCS#11 implementation runs on Windows, Linux, macOS, and other supported
    //  operating systems.

    CkPkcs11 pkcs11;

    //  Use the PKCS#11 driver (.dll, .so, or .dylib) for your particular HSM.
    pkcs11.put_SharedLibPath("C:/Program Files (x86)/Gemalto/IDGo 800 PKCS#11/IDPrimePKCS11.dll");

    //  The HSM PIN should come from a secure source rather than being hard-coded.
    const char *pin = "0000";

    //  Normal user = 1
    int userType = 1;

    success = pkcs11.QuickSession(userType,pin);
    if (success == false) {
        std::cout << pkcs11.lastErrorText() << "\r\n";
        return;
    }

    //  Provide a template describing the PKCS#11 object to find: an RSA private key labeled
    //  "MySshKey".  For how such a key is originally imported, see
    //  PKCS11 Import SSH Key
    CkJsonObject jsonTemplate;
    jsonTemplate.UpdateString("class","private_key");
    jsonTemplate.UpdateString("key_type","rsa");
    jsonTemplate.UpdateString("label","MySshKey");

    unsigned long privKeyHandle = pkcs11.FindObject(jsonTemplate);
    if (privKeyHandle == 0) {
        std::cout << pkcs11.lastErrorText() << "\r\n";
        return;
    }

    //  The handle is only valid for the duration of this PKCS#11 session.  To use the key in a
    //  later session, find it again.
    std::cout << "private key handle: " << privKeyHandle << "\r\n";

    //  Find the corresponding public key by changing the class in the same template.
    jsonTemplate.UpdateString("class","public_key");

    unsigned long pubKeyHandle = pkcs11.FindObject(jsonTemplate);
    if (pubKeyHandle == 0) {
        std::cout << pkcs11.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "public key handle: " << pubKeyHandle << "\r\n";

    //  Create an empty SSH key object and tell it to use the PKCS#11 handles, indicating the key type.
    CkSshKey sshKey;
    success = sshKey.UsePkcs11(pkcs11,privKeyHandle,pubKeyHandle,"rsa");
    if (success == false) {
        std::cout << sshKey.lastErrorText() << "\r\n";
        return;
    }

    CkSsh ssh;

    int port = 22;
    success = ssh.Connect("ssh.example.com",port);
    if (success == false) {
        std::cout << ssh.lastErrorText() << "\r\n";
        return;
    }

    //  Authentication uses the existing PKCS#11 session.  The signing happens on the smart card --
    //  the private key never leaves the device.
    success = ssh.AuthenticatePk("mySshLogin",sshKey);
    if (success == false) {
        std::cout << ssh.lastErrorText() << "\r\n";
        return;
    }

    std::cout << "Public-key authentication successful." << "\r\n";

    //  ... use the authenticated SSH session ...

    ssh.Disconnect();

    pkcs11.Logout();
    pkcs11.CloseSession();
    }