gnutls.c

video linux conference

    p_session->pf_close = gnutls_SessionClose;

    ((tls_session_sys_t *)p_session->p_sys)->b_handshaked = VLC_FALSE;
    ((tls_session_sys_t *)p_session->p_sys)->psz_hostname = NULL;

    i_val = gnutls_init( &session, GNUTLS_SERVER );
    if( i_val != 0 )
    {
        msg_Err( p_server, "Cannot initialize TLS session : %s",
                 gnutls_strerror( i_val ) );
        goto error;
    }

    ((tls_session_sys_t *)p_session->p_sys)->session = session;

    i_val = gnutls_set_default_priority( session );
    if( i_val < 0 )
    {
        msg_Err( p_server, "Cannot set ciphers priorities : %s",
                 gnutls_strerror( i_val ) );
        gnutls_deinit( session );
        goto error;
    }

    i_val = gnutls_credentials_set( session, GNUTLS_CRD_CERTIFICATE,
                                    p_server_sys->x509_cred );
    if( i_val < 0 )
    {
        msg_Err( p_server, "Cannot set TLS session credentials : %s",
                 gnutls_strerror( i_val ) );
        gnutls_deinit( session );
        goto error;
    }

    if( p_session->pf_handshake2 == gnutls_HandshakeAndValidate )
        gnutls_certificate_server_set_request( session, GNUTLS_CERT_REQUIRE );

    gnutls_dh_set_prime_bits( session, get_Int( p_server, "dh-bits" ) );

    /* Session resumption support */
    gnutls_db_set_cache_expiration( session, get_Int( p_server,
                                    "tls-cache-expiration" ) );
    gnutls_db_set_retrieve_function( session, cb_fetch );
    gnutls_db_set_remove_function( session, cb_delete );
    gnutls_db_set_store_function( session, cb_store );
    gnutls_db_set_ptr( session, p_server );

    return p_session;

error:
    free( p_session->p_sys );
    vlc_object_detach( p_session );
    vlc_object_destroy( p_session );
    return NULL;
}


/*****************************************************************************
 * tls_ServerDelete:
 *****************************************************************************
 * Releases data allocated with tls_ServerCreate.
 *****************************************************************************/
static void
gnutls_ServerDelete( tls_server_t *p_server )
{
    tls_server_sys_t *p_sys;
    p_sys = (tls_server_sys_t *)p_server->p_sys;

    vlc_mutex_destroy( &p_sys->cache_lock );
    free( p_sys->p_cache );

    vlc_object_detach( p_server );
    vlc_object_destroy( p_server );

    /* all sessions depending on the server are now deinitialized */
    gnutls_certificate_free_credentials( p_sys->x509_cred );
    gnutls_dh_params_deinit( p_sys->dh_params );
    free( p_sys );
}


/*****************************************************************************
 * tls_ServerAddCA:
 *****************************************************************************
 * Adds one or more certificate authorities.
 * Returns -1 on error, 0 on success.
 *****************************************************************************/
static int
gnutls_ServerAddCA( tls_server_t *p_server, const char *psz_ca_path )
{
    int val;
    tls_server_sys_t *p_sys;

    p_sys = (tls_server_sys_t *)(p_server->p_sys);

    val = gnutls_certificate_set_x509_trust_file( p_sys->x509_cred,
                                                  psz_ca_path,
                                                  GNUTLS_X509_FMT_PEM );
    if( val < 0 )
    {
        msg_Err( p_server, "Cannot add trusted CA (%s) : %s", psz_ca_path,
                 gnutls_strerror( val ) );
        return VLC_EGENERIC;
    }
    msg_Dbg( p_server, " %d trusted CA added (%s)", val, psz_ca_path );

    /* enables peer's certificate verification */
    p_sys->pf_handshake2 = gnutls_HandshakeAndValidate;

    return VLC_SUCCESS;
}


/*****************************************************************************
 * tls_ServerAddCRL:
 *****************************************************************************
 * Adds a certificates revocation list to be sent to TLS clients.
 * Returns -1 on error, 0 on success.
 *****************************************************************************/
static int
gnutls_ServerAddCRL( tls_server_t *p_server, const char *psz_crl_path )
{
    int val;

    val = gnutls_certificate_set_x509_crl_file( ((tls_server_sys_t *)
                                                (p_server->p_sys))->x509_cred,
                                                psz_crl_path,
                                                GNUTLS_X509_FMT_PEM );
    if( val < 0 )
    {
        msg_Err( p_server, "Cannot add CRL (%s) : %s", psz_crl_path,
                 gnutls_strerror( val ) );
        return VLC_EGENERIC;
    }
    msg_Dbg( p_server, "%d CRL added (%s)", val, psz_crl_path );
    return VLC_SUCCESS;
}
    

/*****************************************************************************
 * tls_ServerCreate:
 *****************************************************************************
 * Allocates a whole server's TLS credentials.
 * Returns NULL on error.
 *****************************************************************************/
static tls_server_t *
gnutls_ServerCreate( tls_t *p_tls, const char *psz_cert_path,
                     const char *psz_key_path )
{
    tls_server_t *p_server;
    tls_server_sys_t *p_sys;
    int val;

    msg_Dbg( p_tls, "Creating TLS server" );

    p_sys = (tls_server_sys_t *)malloc( sizeof(struct tls_server_sys_t) );
    if( p_sys == NULL )
        return NULL;

    p_sys->i_cache_size = get_Int( p_tls, "tls-cache-size" );
    p_sys->p_cache = (struct saved_session_t *)calloc( p_sys->i_cache_size,
                                           sizeof( struct saved_session_t ) );
    if( p_sys->p_cache == NULL )
    {
        free( p_sys );
        return NULL;
    }
    p_sys->p_store = p_sys->p_cache;

    p_server = vlc_object_create( p_tls, sizeof(struct tls_server_t) );
    if( p_server == NULL )
    {
        free( p_sys->p_cache );
        free( p_sys );
        return NULL;
    }

    vlc_object_attach( p_server, p_tls );

    p_server->p_sys = p_sys;
    p_server->pf_delete = gnutls_ServerDelete;
    p_server->pf_add_CA = gnutls_ServerAddCA;
    p_server->pf_add_CRL = gnutls_ServerAddCRL;
    p_server->pf_session_prepare = gnutls_ServerSessionPrepare;

    /* No certificate validation by default */
    p_sys->pf_handshake2 = gnutls_ContinueHandshake;

    /* FIXME: check for errors */
    vlc_mutex_init( p_server, &p_sys->cache_lock );

    /* Sets server's credentials */
    val = gnutls_certificate_allocate_credentials( &p_sys->x509_cred );
    if( val != 0 )
    {
        msg_Err( p_server, "Cannot allocate X509 credentials : %s",
                 gnutls_strerror( val ) );
        goto error;
    }

    val = gnutls_certificate_set_x509_key_file( p_sys->x509_cred,
                                                psz_cert_path, psz_key_path,
                                                GNUTLS_X509_FMT_PEM );
    if( val < 0 )
    {
        msg_Err( p_server, "Cannot set certificate chain or private key : %s",
                 gnutls_strerror( val ) );
        gnutls_certificate_free_credentials( p_sys->x509_cred );
        goto error;
    }

    /* FIXME:
     * - regenerate these regularly
     * - support other ciper suites
     */
    val = gnutls_dh_params_init( &p_sys->dh_params );
    if( val >= 0 )
    {
        msg_Dbg( p_server, "Computing Diffie Hellman ciphers parameters" );
        val = gnutls_dh_params_generate2( p_sys->dh_params,
                                          get_Int( p_tls, "dh-bits" ) );
    }
    if( val < 0 )
    {
        msg_Err( p_server, "Cannot initialize DH cipher suites : %s",
                 gnutls_strerror( val ) );
        gnutls_certificate_free_credentials( p_sys->x509_cred );
        goto error;
    }
    msg_Dbg( p_server, "Ciphers parameters computed" );

    gnutls_certificate_set_dh_params( p_sys->x509_cred, p_sys->dh_params);

    return p_server;

error:
    vlc_mutex_destroy( &p_sys->cache_lock );
    vlc_object_detach( p_server );
    vlc_object_destroy( p_server );
    free( p_sys );
    return NULL;
}


/*****************************************************************************
 * gcrypt thread option VLC implementation:
 *****************************************************************************/
vlc_object_t *__p_gcry_data;

static int gcry_vlc_mutex_init( void **p_sys )
{
    int i_val;
    vlc_mutex_t *p_lock = (vlc_mutex_t *)malloc( sizeof( vlc_mutex_t ) );

    if( p_lock == NULL)
        return ENOMEM;

    i_val = vlc_mutex_init( __p_gcry_data, p_lock );
    if( i_val )
        free( p_lock );
    else
        *p_sys = p_lock;
    return i_val;
}

static int gcry_vlc_mutex_destroy( void **p_sys )
{
    int i_val;
    vlc_mutex_t *p_lock = (vlc_mutex_t *)*p_sys;

    i_val = vlc_mutex_destroy( p_lock );
    free( p_lock );
    return i_val;
}

static int gcry_vlc_mutex_lock( void **p_sys )
{
    return vlc_mutex_lock( (vlc_mutex_t *)*p_sys );
}

static int gcry_vlc_mutex_unlock( void **lock )
{
    return vlc_mutex_unlock( (vlc_mutex_t *)*lock );
}

static struct gcry_thread_cbs gcry_threads_vlc =
{
    GCRY_THREAD_OPTION_USER,
    NULL,
    gcry_vlc_mutex_init,
    gcry_vlc_mutex_destroy,
    gcry_vlc_mutex_lock,
    gcry_vlc_mutex_unlock
};


/*****************************************************************************
 * Module initialization
 *****************************************************************************/
static int
Open( vlc_object_t *p_this )
{
    tls_t *p_tls = (tls_t *)p_this;

    vlc_value_t lock, count;

    var_Create( p_this->p_libvlc, "gnutls_mutex", VLC_VAR_MUTEX );
    var_Get( p_this->p_libvlc, "gnutls_mutex", &lock );
    vlc_mutex_lock( lock.p_address );

    /* Initialize GnuTLS only once */
    var_Create( p_this->p_libvlc, "gnutls_count", VLC_VAR_INTEGER );
    var_Get( p_this->p_libvlc, "gnutls_count", &count);

    if( count.i_int == 0)
    {
        const char *psz_version;

        __p_gcry_data = VLC_OBJECT( p_this->p_vlc );

        gcry_control (GCRYCTL_SET_THREAD_CBS, &gcry_threads_vlc);
        if( gnutls_global_init( ) )
        {
            msg_Warn( p_this, "cannot initialize GnuTLS" );
            vlc_mutex_unlock( lock.p_address );
            return VLC_EGENERIC;
        }
        /*
         * FIXME: in fact, we currently depends on 1.0.17, but it breaks on
         * Debian which as a patched 1.0.16 (which we can use).
         */
        psz_version = gnutls_check_version( "1.0.16" );
        if( psz_version == NULL )
        {
            gnutls_global_deinit( );
            vlc_mutex_unlock( lock.p_address );
            msg_Err( p_this, "unsupported GnuTLS version" );
            return VLC_EGENERIC;
        }
        msg_Dbg( p_this, "GnuTLS v%s initialized", psz_version );
    }

    count.i_int++;
    var_Set( p_this->p_libvlc, "gnutls_count", count);
    vlc_mutex_unlock( lock.p_address );

    p_tls->pf_server_create = gnutls_ServerCreate;
    p_tls->pf_client_create = gnutls_ClientCreate;
    return VLC_SUCCESS;
}


/*****************************************************************************
 * Module deinitialization
 *****************************************************************************/
static void
Close( vlc_object_t *p_this )
{
    /*tls_t *p_tls = (tls_t *)p_this;
    tls_sys_t *p_sys = (tls_sys_t *)(p_this->p_sys);*/

    vlc_value_t lock, count;

    var_Create( p_this->p_libvlc, "gnutls_mutex", VLC_VAR_MUTEX );
    var_Get( p_this->p_libvlc, "gnutls_mutex", &lock );
    vlc_mutex_lock( lock.p_address );

    var_Create( p_this->p_libvlc, "gnutls_count", VLC_VAR_INTEGER );
    var_Get( p_this->p_libvlc, "gnutls_count", &count);
    count.i_int--;
    var_Set( p_this->p_libvlc, "gnutls_count", count);

    if( count.i_int == 0 )
    {
        gnutls_global_deinit( );
        msg_Dbg( p_this, "GnuTLS deinitialized" );
    }

    vlc_mutex_unlock( lock.p_address );
}