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 <CkPkcs11W.h>
#include <CkJsonObjectW.h>
#include <CkSshKeyW.h>
#include <CkSshW.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.

    CkPkcs11W pkcs11;

    //  Use the PKCS#11 driver (.dll, .so, or .dylib) for your particular HSM.
    pkcs11.put_SharedLibPath(L"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 wchar_t *pin = L"0000";

    //  Normal user = 1
    int userType = 1;

    success = pkcs11.QuickSession(userType,pin);
    if (success == false) {
        wprintf(L"%s\n",pkcs11.lastErrorText());
        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
    CkJsonObjectW jsonTemplate;
    jsonTemplate.UpdateString(L"class",L"private_key");
    jsonTemplate.UpdateString(L"key_type",L"rsa");
    jsonTemplate.UpdateString(L"label",L"MySshKey");

    unsigned long privKeyHandle = pkcs11.FindObject(jsonTemplate);
    if (privKeyHandle == 0) {
        wprintf(L"%s\n",pkcs11.lastErrorText());
        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.
    wprintf(L"private key handle: %u\n",privKeyHandle);

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

    unsigned long pubKeyHandle = pkcs11.FindObject(jsonTemplate);
    if (pubKeyHandle == 0) {
        wprintf(L"%s\n",pkcs11.lastErrorText());
        return;
    }

    wprintf(L"public key handle: %u\n",pubKeyHandle);

    //  Create an empty SSH key object and tell it to use the PKCS#11 handles, indicating the key type.
    CkSshKeyW sshKey;
    success = sshKey.UsePkcs11(pkcs11,privKeyHandle,pubKeyHandle,L"rsa");
    if (success == false) {
        wprintf(L"%s\n",sshKey.lastErrorText());
        return;
    }

    CkSshW ssh;

    int port = 22;
    success = ssh.Connect(L"ssh.example.com",port);
    if (success == false) {
        wprintf(L"%s\n",ssh.lastErrorText());
        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(L"mySshLogin",sshKey);
    if (success == false) {
        wprintf(L"%s\n",ssh.lastErrorText());
        return;
    }

    wprintf(L"Public-key authentication successful.\n");

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

    ssh.Disconnect();

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