gnutls.c

video linux conference

{
    tls_session_sys_t *p_sys;

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

    if( p_sys->b_handshaked == VLC_TRUE )
        gnutls_bye( p_sys->session, GNUTLS_SHUT_WR );
    gnutls_deinit( p_sys->session );

    if( p_sys->psz_hostname != NULL )
        free( p_sys->psz_hostname );

    vlc_object_detach( p_session );
    vlc_object_destroy( p_session );

    free( p_sys );
}

static void
gnutls_ClientDelete( tls_session_t *p_session )
{
    /* On the client-side, credentials are re-allocated per session */
    gnutls_certificate_credentials x509_cred =
                        ((tls_client_sys_t *)(p_session->p_sys))->x509_cred;

    gnutls_SessionClose( p_session );

    /* credentials must be free'd *after* gnutls_deinit() */
    gnutls_certificate_free_credentials( x509_cred );
}

inline int
is_regular( const char *psz_filename )
{
#ifdef HAVE_SYS_STAT_H
    struct stat st;

    return ( stat( psz_filename, &st ) == 0 )
        && S_ISREG( st.st_mode );
#else
    return 1;
#endif
}

static int
gnutls_Addx509Directory( vlc_object_t *p_this,
                         gnutls_certificate_credentials cred,
                         const char *psz_dirname,
                         vlc_bool_t private )
{
    DIR* dir;
    struct dirent *p_ent;
    int i_len;

    if( *psz_dirname == '\0' )
        psz_dirname = ".";

    dir = opendir( psz_dirname );
    if( dir == NULL )
    {
        msg_Warn( p_this, "Cannot open directory (%s) : %s", psz_dirname,
                  strerror( errno ) );
        return VLC_EGENERIC;
    }

    i_len = strlen( psz_dirname ) + 2;

    while( ( p_ent = readdir( dir ) ) != NULL )
    {
        char *psz_filename;

        psz_filename = (char *)malloc( i_len + strlen( p_ent->d_name ) );
        if( psz_filename == NULL )
        {
            closedir( dir );
            return VLC_ENOMEM;
        }

        sprintf( psz_filename, "%s/%s", psz_dirname, p_ent->d_name );
        /* we neglect the race condition here - not security sensitive */
        if( is_regular( psz_filename ) )
        {
            int i;

            i = (private)
                ? gnutls_certificate_set_x509_key_file( cred, psz_filename,
                                                        psz_filename,
                                                        GNUTLS_X509_FMT_PEM )
                : gnutls_certificate_set_x509_trust_file( cred, psz_filename,
                                                          GNUTLS_X509_FMT_PEM
                                                          );
            if( i < 0 )
            {
                msg_Warn( p_this, "Cannot add x509 certificate (%s) : %s",
                          psz_filename, gnutls_strerror( i ) );
            }
        }
        free( psz_filename );
    }

    closedir( dir );
    return VLC_SUCCESS;
}

/*****************************************************************************
 * tls_ClientCreate:
 *****************************************************************************
 * Initializes client-side TLS session data.
 *****************************************************************************/
static tls_session_t *
gnutls_ClientCreate( tls_t *p_tls )
{
    tls_session_t *p_session = NULL;
    tls_client_sys_t *p_sys = NULL;
    int i_val;
    const int cert_type_priority[3] =
    {
        GNUTLS_CRT_X509,
        0
    };

    p_sys = (tls_client_sys_t *)malloc( sizeof(struct tls_client_sys_t) );
    if( p_sys == NULL )
        return NULL;
   
    p_session = (struct tls_session_t *)vlc_object_create ( p_tls, sizeof(struct tls_session_t) );
    if( p_session == NULL )
    {
        free( p_sys );
        return NULL;
    }

    p_session->p_sys = p_sys;
    p_session->sock.p_sys = p_session;
    p_session->sock.pf_send = gnutls_Send;
    p_session->sock.pf_recv = gnutls_Recv;
    p_session->pf_handshake = gnutls_BeginHandshake;
    p_session->pf_close = gnutls_ClientDelete;

    p_sys->session.b_handshaked = VLC_FALSE;
    p_sys->session.psz_hostname = NULL;

    vlc_object_attach( p_session, p_tls );

    i_val = gnutls_certificate_allocate_credentials( &p_sys->x509_cred );
    if( i_val != 0 )
    {
        msg_Err( p_tls, "Cannot allocate X509 credentials : %s",
                 gnutls_strerror( i_val ) );
        goto error;
    }

    if( get_Bool( p_tls, "tls-check-cert" ) )
    {
        /* FIXME: support for changing path/using multiple paths */
        char *psz_path;
        const char *psz_homedir;

        psz_homedir = p_tls->p_vlc->psz_homedir;
        psz_path = (char *)malloc( strlen( psz_homedir )
                                   + sizeof( CONFIG_DIR ) + 12 );
        if( psz_path == NULL )
        {
            gnutls_certificate_free_credentials( p_sys->x509_cred );
            goto error;
        }

        sprintf( psz_path, "%s/"CONFIG_DIR"/ssl/certs", psz_homedir );
        gnutls_Addx509Directory( (vlc_object_t *)p_session, p_sys->x509_cred,
                                 psz_path, VLC_FALSE );

        free( psz_path );
        p_session->pf_handshake2 = gnutls_HandshakeAndValidate;
    }
    else
        p_session->pf_handshake2 = gnutls_ContinueHandshake;

    {
        /* FIXME: support for changing path/using multiple paths */
        char *psz_path;
        const char *psz_homedir;

        psz_homedir = p_tls->p_vlc->psz_homedir;
        psz_path = (char *)malloc( strlen( psz_homedir )
                                   + sizeof( CONFIG_DIR ) + 14 );
        if( psz_path == NULL )
        {
            gnutls_certificate_free_credentials( p_sys->x509_cred );
            goto error;
        }

        sprintf( psz_path, "%s/"CONFIG_DIR"/ssl/private", psz_homedir );
        gnutls_Addx509Directory( (vlc_object_t *)p_session, p_sys->x509_cred,
                                 psz_path, VLC_TRUE );

        free( psz_path );
    }

    i_val = gnutls_init( &p_sys->session.session, GNUTLS_CLIENT );
    if( i_val != 0 )
    {
        msg_Err( p_tls, "Cannot initialize TLS session : %s",
                 gnutls_strerror( i_val ) );
        gnutls_certificate_free_credentials( p_sys->x509_cred );
        goto error;
    }

    i_val = gnutls_set_default_priority( p_sys->session.session );
    if( i_val < 0 )
    {
        msg_Err( p_tls, "Cannot set ciphers priorities : %s",
                 gnutls_strerror( i_val ) );
        gnutls_deinit( p_sys->session.session );
        gnutls_certificate_free_credentials( p_sys->x509_cred );
        goto error;
    }

    i_val = gnutls_certificate_type_set_priority( p_sys->session.session,
                                                  cert_type_priority );
    if( i_val < 0 )
    {
        msg_Err( p_tls, "Cannot set certificate type priorities : %s",
                 gnutls_strerror( i_val ) );
        gnutls_deinit( p_sys->session.session );
        gnutls_certificate_free_credentials( p_sys->x509_cred );
        goto error;
    }

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

    return p_session;

error:
    vlc_object_detach( p_session );
    vlc_object_destroy( p_session );
    free( p_sys );

    return NULL;
}


/*****************************************************************************
 * TLS session resumption callbacks
 *****************************************************************************/
static int cb_store( void *p_server, gnutls_datum key, gnutls_datum data )
{
    tls_server_sys_t *p_sys = ((tls_server_t *)p_server)->p_sys;

    if( ( p_sys->i_cache_size == 0 )
     || ( key.size > MAX_SESSION_ID )
     || ( data.size > MAX_SESSION_DATA ) )
        return -1;

    vlc_mutex_lock( &p_sys->cache_lock );

    memcpy( p_sys->p_store->id, key.data, key.size);
    memcpy( p_sys->p_store->data, data.data, data.size );
    p_sys->p_store->i_idlen = key.size;
    p_sys->p_store->i_datalen = data.size;

    p_sys->p_store++;
    if( ( p_sys->p_store - p_sys->p_cache ) == p_sys->i_cache_size )
        p_sys->p_store = p_sys->p_cache;

    vlc_mutex_unlock( &p_sys->cache_lock );

    return 0;
}


static const gnutls_datum err_datum = { NULL, 0 };

static gnutls_datum cb_fetch( void *p_server, gnutls_datum key )
{
    tls_server_sys_t *p_sys = ((tls_server_t *)p_server)->p_sys;
    saved_session_t *p_session, *p_end;

    p_session = p_sys->p_cache;
    p_end = p_session + p_sys->i_cache_size;

    vlc_mutex_lock( &p_sys->cache_lock );

    while( p_session < p_end )
    {
        if( ( p_session->i_idlen == key.size )
         && !memcmp( p_session->id, key.data, key.size ) )
        {
            gnutls_datum data;

            data.size = p_session->i_datalen;

            data.data = gnutls_malloc( data.size );
            if( data.data == NULL )
            {
                vlc_mutex_unlock( &p_sys->cache_lock );
                return err_datum;
            }

            memcpy( data.data, p_session->data, data.size );
            vlc_mutex_unlock( &p_sys->cache_lock );
            return data;
        }
        p_session++;
    }

    vlc_mutex_unlock( &p_sys->cache_lock );

    return err_datum;
}


static int cb_delete( void *p_server, gnutls_datum key )
{
    tls_server_sys_t *p_sys = ((tls_server_t *)p_server)->p_sys;
    saved_session_t *p_session, *p_end;

    p_session = p_sys->p_cache;
    p_end = p_session + p_sys->i_cache_size;

    vlc_mutex_lock( &p_sys->cache_lock );

    while( p_session < p_end )
    {
        if( ( p_session->i_idlen == key.size )
         && !memcmp( p_session->id, key.data, key.size ) )
        {
            p_session->i_datalen = p_session->i_idlen = 0;
            vlc_mutex_unlock( &p_sys->cache_lock );
            return 0;
        }
        p_session++;
    }

    vlc_mutex_unlock( &p_sys->cache_lock );

    return -1;
}


/*****************************************************************************
 * tls_ServerSessionPrepare:
 *****************************************************************************
 * Initializes server-side TLS session data.
 *****************************************************************************/
static tls_session_t *
gnutls_ServerSessionPrepare( tls_server_t *p_server )
{
    tls_session_t *p_session;
    tls_server_sys_t *p_server_sys;
    gnutls_session session;
    int i_val;

    p_session = vlc_object_create( p_server, sizeof (struct tls_session_t) );
    if( p_session == NULL )
        return NULL;
    
    p_session->p_sys = malloc( sizeof(struct tls_session_sys_t) );
    if( p_session->p_sys == NULL )
    {
        vlc_object_destroy( p_session );
        return NULL;
    }

    vlc_object_attach( p_session, p_server );

    p_server_sys = (tls_server_sys_t *)p_server->p_sys;
    p_session->sock.p_sys = p_session;
    p_session->sock.pf_send = gnutls_Send;
    p_session->sock.pf_recv = gnutls_Recv;
    p_session->pf_handshake = gnutls_BeginHandshake;
    p_session->pf_handshake2 = p_server_sys->pf_handshake2;