gnutls TLS module

modules/misc/Modules.am

@@ -8,4 +8,5 @@ SOURCES_qte_main = qte_main.cpp
 SOURCES_freetype = freetype.c
 SOURCES_logger = logger.c
 SOURCES_vod_rtsp = rtsp.c
+SOURCES_gnutls = gnutls.c
 SOURCES_svg = svg.c

modules/misc/gnutls.c

+/*****************************************************************************
+ * tls.c
+ *****************************************************************************
+ * Copyright (C) 2004 VideoLAN
+ * $Id: httpd.c 8263 2004-07-24 09:06:58Z courmisch $
+ *
+ * Authors: Remi Denis-Courmont <courmisch@via.ecp.fr>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
+ *****************************************************************************/
+
+/*
+ * TODO:
+ * - libgcrypt thread-safety !!!
+ * - fix FIXMEs,
+ * - gnutls version check,
+ * - client side stuff,
+ * - server-side client cert validation,
+ * - client-side server cert validation (?).
+ */
+
+ 
+/*****************************************************************************
+ * Preamble
+ *****************************************************************************/
+#include <stdlib.h>
+#include <vlc/vlc.h>
+
+#include "vlc_tls.h"
+
+
+#include <gnutls/gnutls.h>
+
+#define DH_BITS 1024
+
+
+/*****************************************************************************
+ * Module descriptor
+ *****************************************************************************/
+static int  Open ( vlc_object_t * );
+static void Close( vlc_object_t * );
+
+#define DH_BITS_TEXT N_("Diffie-Hellman prime bits")
+#define DH_BITS_LONGTEXT N_( \
+    "Allows you to modify the Diffie-Hellman prime's number of bits" \
+    "(used for TLS or SSL-based server-side encryption)." )
+
+vlc_module_begin();
+    set_description( _("GnuTLS TLS encryption layer") );
+    set_capability( "tls", 1 );
+    set_callbacks( Open, Close );
+
+    /*add_integer( "dh-bits", 1024, NULL, DH_BITS_TEXT,
+                 DH_BITS_LONGTEXT, VLC_TRUE );*/
+vlc_module_end();
+
+
+
+typedef struct tls_server_sys_t
+{
+    gnutls_certificate_credentials x509_cred;
+    gnutls_dh_params dh_params;
+} tls_server_sys_t;
+
+
+/*****************************************************************************
+ * tls_Send:
+ *****************************************************************************
+ * Sends data through a TLS session.
+ *****************************************************************************/
+static int
+gnutls_Send( tls_session_t *p_session, const char *buf, int i_length )
+{
+    int val;
+
+    val = gnutls_record_send( *(gnutls_session *)(p_session->p_sys),
+                              buf, i_length );
+    return val < 0 ? -1 : val;
+}
+
+
+/*****************************************************************************
+ * tls_Recv:
+ *****************************************************************************
+ * Receives data through a TLS session
+ *****************************************************************************/
+static int
+gnutls_Recv( tls_session_t *p_session, char *buf, int i_length )
+{
+    int val;
+
+    val = gnutls_record_recv( *(gnutls_session *)(p_session->p_sys),
+                              buf, i_length );
+    return val < 0 ? -1 : val;
+}
+
+
+/*****************************************************************************
+ * tls_SessionHandshake:
+ *****************************************************************************
+ * Establishes TLS session with a peer through socket <fd>
+ * Returns NULL on error (do NOT call tls_SessionClose in case of error or
+ * re-use the session structure).
+ *****************************************************************************/
+static tls_session_t *
+gnutls_SessionHandshake( tls_session_t *p_session, int fd )
+{
+    int val;
+    gnutls_session *p_sys;
+
+    p_sys = (gnutls_session *)(p_session->p_sys);
+
+    gnutls_transport_set_ptr( *p_sys, (gnutls_transport_ptr)fd);
+    val = gnutls_handshake( *p_sys );
+    if( val < 0 )
+    {
+        gnutls_deinit( *p_sys );
+        msg_Err( p_session->p_tls, "TLS handshake failed : %s",
+                 gnutls_strerror( val ) );
+        free( p_sys );
+        free( p_session );
+        return NULL;
+    }
+    return p_session;
+}
+
+
+/*****************************************************************************
+ * tls_ServerCreate:
+ *****************************************************************************
+ * Terminates a TLS session and releases session data.
+ *****************************************************************************/
+static void
+gnutls_SessionClose( tls_session_t *p_session )
+{
+    gnutls_session *p_sys;
+
+    p_sys = (gnutls_session *)(p_session->p_sys);
+
+    gnutls_bye( *p_sys, GNUTLS_SHUT_WR );
+    gnutls_deinit ( *p_sys );
+    free( p_sys );
+    free( p_session );
+}
+
+
+/*****************************************************************************
+ * tls_ServerSessionPrepare:
+ *****************************************************************************
+ * Initializes a server-side TLS session data
+ *****************************************************************************/
+static tls_session_t *
+gnutls_ServerSessionPrepare( tls_server_t *p_server )
+{
+    tls_session_t *p_session;
+    gnutls_session *p_sys;
+    int val;
+
+    p_sys = (gnutls_session *)malloc( sizeof(gnutls_session *) );
+    if( p_sys == NULL )
+        return NULL;
+
+    val = gnutls_init( p_sys, GNUTLS_SERVER );
+    if( val != 0 )
+    {
+        msg_Err( p_server->p_tls, "Cannot initialize TLS session : %s",
+                 gnutls_strerror( val ) );
+        free( p_sys );
+        return NULL;
+    }
+   
+    val = gnutls_set_default_priority( *p_sys );
+    if( val < 0 )
+    {
+        msg_Err( p_server->p_tls, "Cannot set ciphers priorities : %s",
+                 gnutls_strerror( val ) );
+        gnutls_deinit( *p_sys );
+        free( p_sys );
+        return NULL;
+    }
+
+    val = gnutls_credentials_set( *p_sys, GNUTLS_CRD_CERTIFICATE,
+                                  ((tls_server_sys_t *)(p_server->p_sys))
+                                  ->x509_cred );
+    if( val < 0 )
+    {
+        msg_Err( p_server->p_tls, "Cannot set TLS session credentials : %s",
+                 gnutls_strerror( val ) );
+        gnutls_deinit( *p_sys );
+        free( p_sys );
+        return NULL;
+    }
+
+    /* TODO: support for client authentication */
+    /*gnutls_certificate_server_set_request( p_session->session,
+                                           GNUTLS_CERT_REQUEST ); */
+
+    gnutls_dh_set_prime_bits( *p_sys, DH_BITS );
+
+    p_session = malloc( sizeof (struct tls_session_t) );
+    if( p_session == NULL )
+    {
+        gnutls_deinit( *p_sys );
+        free( p_sys );
+        return NULL;
+    }
+
+    p_session->p_tls = p_server->p_tls;
+    p_session->p_server = p_server;
+    p_session->p_sys = p_sys;
+    p_session->pf_handshake =gnutls_SessionHandshake;
+    p_session->pf_close = gnutls_SessionClose;
+    p_session->pf_send = gnutls_Send;
+    p_session->pf_recv = gnutls_Recv;
+
+    return p_session;
+}
+
+
+/*****************************************************************************
+ * tls_ServerDelete:
+ *****************************************************************************
+ * Releases data allocated with tls_ServerCreate
+ *****************************************************************************/
+static void
+gnutls_ServerDelete( tls_server_t *p_server )
+{
+    gnutls_certificate_free_credentials(
+                                       ((tls_server_sys_t *)(p_server->p_sys))
+                                         ->x509_cred );
+    free( p_server->p_sys );
+    free( p_server );
+}
+
+
+/*****************************************************************************
+ * tls_ServerAddCA:
+ *****************************************************************************
+ * Adds one or more certificate authorities.
+ * TODO: we are not able to check the client credentials yet, so this function
+ * is pretty useless.
+ * Returns -1 on error, 0 on success.
+ *****************************************************************************/
+static int
+gnutls_ServerAddCA( tls_server_t *p_server, const char *psz_ca_path )
+{
+    int val;
+
+    val = gnutls_certificate_set_x509_trust_file( ((tls_server_sys_t *)
+                                                  (p_server->p_sys))
+                                                    ->x509_cred,
+                                                  psz_ca_path,
+                                                  GNUTLS_X509_FMT_PEM );
+    if( val < 0 )
+    {
+        msg_Err( p_server->p_tls, "Cannot add trusted CA (%s) : %s",
+                 psz_ca_path, gnutls_strerror( val ) );
+        gnutls_ServerDelete( p_server );
+        return VLC_EGENERIC;
+    }
+    msg_Dbg( p_server->p_tls, " %d trusted CA added (%s)", val,
+             psz_ca_path );
+    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->p_tls, "Cannot add CRL (%s) : %s",
+                 psz_crl_path, gnutls_strerror( val ) );
+        gnutls_ServerDelete( p_server );
+        return VLC_EGENERIC;
+    }
+    msg_Dbg( p_server->p_tls, "%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_this, const char *psz_cert_path,
+                  const char *psz_key_path )
+{
+    tls_server_t *p_server;
+    tls_server_sys_t *p_server_sys;
+    int val;
+
+    msg_Dbg( p_this, "Creating TLS server" );
+
+    p_server_sys = (tls_server_sys_t *)malloc( sizeof(struct tls_server_sys_t) );
+    if( p_server_sys == NULL )
+        return NULL;
+
+    /* Sets server's credentials */
+    val = gnutls_certificate_allocate_credentials( &p_server_sys->x509_cred );
+    if( val != 0 )
+    {
+        msg_Err( p_this, "Cannot allocate X509 credentials : %s",
+                 gnutls_strerror( val ) );
+        free( p_server_sys );
+        return NULL;
+    }
+
+    val = gnutls_certificate_set_x509_key_file( p_server_sys->x509_cred,
+                                                psz_cert_path, psz_key_path,
+                                                GNUTLS_X509_FMT_PEM );
+    if( val < 0 )
+    {
+        msg_Err( p_this, "Cannot set certificate chain or private key : %s",
+                 gnutls_strerror( val ) );
+        gnutls_certificate_free_credentials( p_server_sys->x509_cred );
+        free( p_server_sys );
+        return NULL;
+    }
+
+    /* FIXME: regenerate these regularly */
+    val = gnutls_dh_params_init( &p_server_sys->dh_params );
+    if( val >= 0 )
+    {
+        msg_Dbg( p_this, "Computing Diffie Hellman ciphers parameters" );
+        val = gnutls_dh_params_generate2( p_server_sys->dh_params, DH_BITS );
+    }
+    if( val < 0 )
+    {
+        msg_Err( p_this, "Cannot initialize DH cipher suites : %s",
+                 gnutls_strerror( val ) );
+        gnutls_certificate_free_credentials( p_server_sys->x509_cred );
+        free( p_server_sys );
+        return NULL;
+    }
+    msg_Dbg( p_this, "Ciphers parameters computed" );
+
+    gnutls_certificate_set_dh_params( p_server_sys->x509_cred,
+                                      p_server_sys->dh_params);
+
+    p_server = (tls_server_t *)malloc( sizeof(struct tls_server_t) );
+    if( p_server == NULL )
+    {
+        free( p_server_sys );
+        return NULL;
+    }
+
+    p_server->p_tls = p_this;
+    p_server->p_sys = p_server_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;
+
+    return p_server;
+}
+
+
+
+
+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, "tls_mutex", VLC_VAR_MUTEX );
+    var_Get( p_this->p_libvlc, "tls_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);
+
+    /* FIXME: should check version number */
+    if( count.i_int == 0)
+    {
+        if( gnutls_global_init( ) )
+        {
+            msg_Warn( p_this, "cannot initialize GNUTLS" );
+            vlc_mutex_unlock( lock.p_address);
+            return VLC_EGENERIC;
+        }
+        msg_Dbg( p_this, "GNUTLS initialized" );
+    }
+
+    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;
+    return VLC_SUCCESS;
+}
+
+
+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);
+}