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 <C_CkPkcs11.h>
#include <C_CkJsonObject.h>
#include <C_CkSshKey.h>
#include <C_CkSsh.h>

void ChilkatSample(void)
    {
    BOOL success;
    HCkPkcs11 pkcs11;
    const char *pin;
    int userType;
    HCkJsonObject jsonTemplate;
    unsigned long privKeyHandle;
    unsigned long pubKeyHandle;
    HCkSshKey sshKey;
    HCkSsh ssh;
    int port;

    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.

    pkcs11 = CkPkcs11_Create();

    //  Use the PKCS#11 driver (.dll, .so, or .dylib) for your particular HSM.
    CkPkcs11_putSharedLibPath(pkcs11,"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.
    pin = "0000";

    //  Normal user = 1
    userType = 1;

    success = CkPkcs11_QuickSession(pkcs11,userType,pin);
    if (success == FALSE) {
        printf("%s\n",CkPkcs11_lastErrorText(pkcs11));
        CkPkcs11_Dispose(pkcs11);
        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
    jsonTemplate = CkJsonObject_Create();
    CkJsonObject_UpdateString(jsonTemplate,"class","private_key");
    CkJsonObject_UpdateString(jsonTemplate,"key_type","rsa");
    CkJsonObject_UpdateString(jsonTemplate,"label","MySshKey");

    privKeyHandle = CkPkcs11_FindObject(pkcs11,jsonTemplate);
    if (privKeyHandle == 0) {
        printf("%s\n",CkPkcs11_lastErrorText(pkcs11));
        CkPkcs11_Dispose(pkcs11);
        CkJsonObject_Dispose(jsonTemplate);
        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.
    printf("private key handle: %u\n",privKeyHandle);

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

    pubKeyHandle = CkPkcs11_FindObject(pkcs11,jsonTemplate);
    if (pubKeyHandle == 0) {
        printf("%s\n",CkPkcs11_lastErrorText(pkcs11));
        CkPkcs11_Dispose(pkcs11);
        CkJsonObject_Dispose(jsonTemplate);
        return;
    }

    printf("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.
    sshKey = CkSshKey_Create();
    success = CkSshKey_UsePkcs11(sshKey,pkcs11,privKeyHandle,pubKeyHandle,"rsa");
    if (success == FALSE) {
        printf("%s\n",CkSshKey_lastErrorText(sshKey));
        CkPkcs11_Dispose(pkcs11);
        CkJsonObject_Dispose(jsonTemplate);
        CkSshKey_Dispose(sshKey);
        return;
    }

    ssh = CkSsh_Create();

    port = 22;
    success = CkSsh_Connect(ssh,"ssh.example.com",port);
    if (success == FALSE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        CkPkcs11_Dispose(pkcs11);
        CkJsonObject_Dispose(jsonTemplate);
        CkSshKey_Dispose(sshKey);
        CkSsh_Dispose(ssh);
        return;
    }

    //  Authentication uses the existing PKCS#11 session.  The signing happens on the smart card --
    //  the private key never leaves the device.
    success = CkSsh_AuthenticatePk(ssh,"mySshLogin",sshKey);
    if (success == FALSE) {
        printf("%s\n",CkSsh_lastErrorText(ssh));
        CkPkcs11_Dispose(pkcs11);
        CkJsonObject_Dispose(jsonTemplate);
        CkSshKey_Dispose(sshKey);
        CkSsh_Dispose(ssh);
        return;
    }

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

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

    CkSsh_Disconnect(ssh);

    CkPkcs11_Logout(pkcs11);
    CkPkcs11_CloseSession(pkcs11);


    CkPkcs11_Dispose(pkcs11);
    CkJsonObject_Dispose(jsonTemplate);
    CkSshKey_Dispose(sshKey);
    CkSsh_Dispose(ssh);

    }