surfer/Test_Qt_Frontend/smartcardauth.cpp

#include "smartcardauth.h"
#include "pindialog.h"
#include <QtNetwork/private/qsslsocket_openssl_symbols_p.h>

#include "engine_sct.h"

#include <string>

ENGINE* SmartCardAuth::e=NULL;
enum_certs_s* SmartCardAuth::certs_found=NULL;
QWidget* SmartCardAuth::parent=0;
bool SmartCardAuth::pin_configured=false;
bool SmartCardAuth::pin_rejected=false;

void SmartCardAuth::initialize() {
    QSslSocketPrivate::ensureInitialized();

    q_ENGINE_load_dynamic();
    e = q_ENGINE_by_id("dynamic");

    //! @todo add library-name
    int r=q_ENGINE_ctrl_cmd_string(e, "SO_PATH", "...library-name...", 0);
    r=q_ENGINE_ctrl_cmd_string(e, "ID", "act", 0);
    r=q_ENGINE_ctrl_cmd_string(e, "LIST_ADD", "1", 0);
    r=q_ENGINE_ctrl_cmd_string(e, "LOAD", NULL, 0);

    if(!r)
    {
        unsigned int err = 0;
        while((err = q_ERR_get_error()))
        {
            char *str = q_ERR_error_string(err, NULL);
            fprintf(stderr,"%s\n", str);
        }
    }

    r=q_ENGINE_init(e);

}

void SmartCardAuth::deinitialize() {
    q_ENGINE_finish(e);
    q_ENGINE_cleanup();
}

void SmartCardAuth::setPinDlgParent(QWidget* p) {
    parent=p;
}

int SmartCardAuth::client_cert_cb(SSL *ssl, X509 **x509, EVP_PKEY **pkey)
{
    // NB: Keep in mind that this function is called for EVERY SSL connection to be opened.

    for(size_t i=certs_found->num_certs;i--;)
    {
        const char *id_p = certs_found->certificate[i].id;

        if(id_p == NULL) continue;

        // Name has the format "slot-x-name-SwissSign_digSig" for the certificate/key we're looking for
        std::string name(certs_found->certificate[i].name);
        std::string compare("-name-SwissSign_digSig");

        // Compare the rightmost part of the retrieved name to locate the certificate/keypair
        size_t pos = name.length() - compare.length();
        if(name.substr(pos) != compare)
            continue;

//        // Filter out the correct certificate depending on well-known sorting criteria
//        // Given example searches for a keyword in the certificate's subject, but since we've got
//        // the decoded certificate as an X509* structure we can check all the fields.
//        X509_NAME* subj_name = q_X509_get_subject_name(certs_found->certificate[i].cert);
//        int maxlen = 2048;
//        char buf[maxlen+1];
//        buf[maxlen]=0;
//        q_X509_NAME_oneline(subj_name, buf, maxlen);
//        std::string subject(buf);

//        const char *compare="CN=Carsten Pluntke";
//        if(subject.find(compare) == std::string::npos)
//            continue;

        // Here we found a suitable certificate.

        // Now prepare the reference to the SmartCard's private key and a copy of the certificate
        // to pass back to the caller.
        *x509 = q_X509_dup(certs_found->certificate[i].cert);
        *pkey = NULL;

        // If we don't have a PIN yet, pop up a dialog, ask for a PIN and pass it along to the engine
        // for usage.
        if(!pin_configured)
        {
            PinDialog dlg(parent);
            int ok=dlg.exec();
            if(ok!=1) return 0;  // User cancelled
            QByteArray pinByteArray=dlg.pin().toAscii();
            char *pin_str = pinByteArray.data();

            // The engine control command takes a copy and overwrites the source array
            if(q_ENGINE_ctrl_cmd_string(e, "PIN", pin_str, 0))
                pin_configured = true;
            else
                return 0;  // Engine refuses to take the PIN

            *pkey = q_ENGINE_load_private_key(e, id_p, NULL, NULL);

            // We do a test authorization on loading of the private key. If the operation fails at all,
            // DON'T try again (see below) or we would instantly lock the card in a single session because
            // of the retries!
            if(!*pkey)
                pin_rejected = true;
        }

        // Second to nth iteration: We skipped the PIN dialog here, now load the key if we don't have the
        // explicit information not to do it (because the PIN is wrong)
        if(!*pkey && !pin_rejected)
            *pkey = q_ENGINE_load_private_key(e, id_p, NULL, NULL);

        break;
    }

    if(!*x509) {
        qWarning("Unable to load certificate");
        return 0;
    }

    if(!*pkey) {
        qWarning("Unable to load key");
        return 0;
    }

    return 1;
}

bool SmartCardAuth::hookInitSslContext(SSL_CTX *ctx)
{    
    bool result = false;

    if(!certs_found)
        result = (q_ENGINE_ctrl_cmd(e, "ENUM_CERTS", 0, &certs_found, NULL, 0) != 0);
    else
        result = true;

#ifdef USE_CERTIFICATE_FILE
    // Load a specific intermediate certificate from a file
    //! @todo PEM-File
    BIO* cert_file= q_BIO_new_file("swsign_interm.pem", "r");
    X509* interm=q_PEM_read_bio_X509(cert_file,NULL,NULL, NULL);
    q_BIO_free(cert_file);

    q_SSL_CTX_add_extra_chain_cert(ctx,interm);
#else
    // Add all of the card's certificates without a private key as intermediate certs
    for(size_t i=certs_found->num_certs;i--;)
    {
        if(certs_found->certificate[i].id == NULL)
            q_SSL_CTX_add_extra_chain_cert(ctx, q_X509_dup(certs_found->certificate[i].cert));
    }
#endif

    q_SSL_CTX_set_client_cert_cb(ctx,client_cert_cb);
    return true;
}