modules/misc/gnutls.c

   1 /*****************************************************************************
   2  * gnutls.c
   3  *****************************************************************************
   4  * Copyright (C) 2004-2006 Rémi Denis-Courmont
   5  * $Id$
   6  *
   7  * Authors: Rémi Denis-Courmont <rem # videolan.org>
   8  *
   9  * This program is free software; you can redistribute it and/or modify
  10  * it under the terms of the GNU General Public License as published by
  11  * the Free Software Foundation; either version 2 of the License, or
  12  * (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  22  *****************************************************************************/
  23
  24 /*****************************************************************************
  25  * Preamble
  26  *****************************************************************************/
  27
  28 #ifdef HAVE_CONFIG_H
  29 # include "config.h"
  30 #endif
  31
  32 #include <vlc_common.h>
  33 #include <vlc_plugin.h>
  34 #include <errno.h>
  35 #include <time.h>
  36
  37 #include <sys/types.h>
  38 #include <errno.h>
  39 #ifdef HAVE_SYS_STAT_H
  40 # include <sys/stat.h>
  41 #endif
  42 #ifdef WIN32
  43 # include <io.h>
  44 #else
  45 # include <unistd.h>
  46 #endif
  47 # include <fcntl.h>
  48
  49
  50 #include <vlc_tls.h>
  51 #include <vlc_charset.h>
  52 #include <vlc_fs.h>
  53 #include <vlc_block.h>
  54
  55 #include <gcrypt.h>
  56 #include <gnutls/gnutls.h>
  57 #include <gnutls/x509.h>
  58
  59 #include <vlc_gcrypt.h>
  60
  61 #define CACHE_TIMEOUT     3600
  62 #define CACHE_SIZE          64
  63
  64 #include "dhparams.h"
  65
  66 #include <assert.h>
  67
  68 /*****************************************************************************
  69  * Module descriptor
  70  *****************************************************************************/
  71 static int  OpenClient  (vlc_object_t *);
  72 static void CloseClient (vlc_object_t *);
  73 static int  OpenServer  (vlc_object_t *);
  74 static void CloseServer (vlc_object_t *);
  75
  76 #define CACHE_TIMEOUT_TEXT N_("Expiration time for resumed TLS sessions")
  77 #define CACHE_TIMEOUT_LONGTEXT N_( \
  78     "It is possible to cache the resumed TLS sessions. This is the expiration "\
  79     "time of the sessions stored in this cache, in seconds." )
  80
  81 #define CACHE_SIZE_TEXT N_("Number of resumed TLS sessions")
  82 #define CACHE_SIZE_LONGTEXT N_( \
  83     "This is the maximum number of resumed TLS sessions that " \
  84     "the cache will hold." )
  85
  86 vlc_module_begin ()
  87     set_shortname( "GnuTLS" )
  88     set_description( N_("GnuTLS transport layer security") )
  89     set_capability( "tls client", 1 )
  90     set_callbacks( OpenClient, CloseClient )
  91     set_category( CAT_ADVANCED )
  92     set_subcategory( SUBCAT_ADVANCED_MISC )
  93
  94     add_obsolete_bool( "tls-check-cert" )
  95     add_obsolete_bool( "tls-check-hostname" )
  96
  97     add_submodule ()
  98         set_description( N_("GnuTLS server") )
  99         set_capability( "tls server", 1 )
 100         set_category( CAT_ADVANCED )
 101         set_subcategory( SUBCAT_ADVANCED_MISC )
 102         set_callbacks( OpenServer, CloseServer )
 103
 104         add_obsolete_integer( "gnutls-dh-bits" )
 105         add_integer( "gnutls-cache-timeout", CACHE_TIMEOUT,
 106                     CACHE_TIMEOUT_TEXT, CACHE_TIMEOUT_LONGTEXT, true )
 107         add_integer( "gnutls-cache-size", CACHE_SIZE, CACHE_SIZE_TEXT,
 108                     CACHE_SIZE_LONGTEXT, true )
 109 vlc_module_end ()
 110
 111 static vlc_mutex_t gnutls_mutex = VLC_STATIC_MUTEX;
 112
 113 /**
 114  * Initializes GnuTLS with proper locking.
 115  * @return VLC_SUCCESS on success, a VLC error code otherwise.
 116  */
 117 static int gnutls_Init (vlc_object_t *p_this)
 118 {
 119     int ret = VLC_EGENERIC;
 120
 121     vlc_gcrypt_init (); /* GnuTLS depends on gcrypt */
 122
 123     vlc_mutex_lock (&gnutls_mutex);
 124     if (gnutls_global_init ())
 125     {
 126         msg_Err (p_this, "cannot initialize GnuTLS");
 127         goto error;
 128     }
 129
 130     const char *psz_version = gnutls_check_version ("1.3.3");
 131     if (psz_version == NULL)
 132     {
 133         msg_Err (p_this, "unsupported GnuTLS version");
 134         gnutls_global_deinit ();
 135         goto error;
 136     }
 137
 138     msg_Dbg (p_this, "GnuTLS v%s initialized", psz_version);
 139     ret = VLC_SUCCESS;
 140
 141 error:
 142     vlc_mutex_unlock (&gnutls_mutex);
 143     return ret;
 144 }
 145
 146
 147 /**
 148  * Deinitializes GnuTLS.
 149  */
 150 static void gnutls_Deinit (vlc_object_t *p_this)
 151 {
 152     vlc_mutex_lock (&gnutls_mutex);
 153
 154     gnutls_global_deinit ();
 155     msg_Dbg (p_this, "GnuTLS deinitialized");
 156     vlc_mutex_unlock (&gnutls_mutex);
 157 }
 158
 159
 160 static int gnutls_Error (vlc_object_t *obj, int val)
 161 {
 162     switch (val)
 163     {
 164         case GNUTLS_E_AGAIN:
 165 #ifdef WIN32
 166             WSASetLastError (WSAEWOULDBLOCK);
 167 #else
 168             errno = EAGAIN;
 169 #endif
 170             break;
 171
 172         case GNUTLS_E_INTERRUPTED:
 173 #ifdef WIN32
 174             WSASetLastError (WSAEINTR);
 175 #else
 176             errno = EINTR;
 177 #endif
 178             break;
 179
 180         default:
 181             msg_Err (obj, "%s", gnutls_strerror (val));
 182 #ifndef NDEBUG
 183             if (!gnutls_error_is_fatal (val))
 184                 msg_Err (obj, "Error above should be handled");
 185 #endif
 186 #ifdef WIN32
 187             WSASetLastError (WSAECONNRESET);
 188 #else
 189             errno = ECONNRESET;
 190 #endif
 191     }
 192     return -1;
 193 }
 194
 195
 196 struct tls_session_sys_t
 197 {
 198     gnutls_session_t session;
 199     char            *psz_hostname;
 200     bool       b_handshaked;
 201 };
 202
 203
 204 /**
 205  * Sends data through a TLS session.
 206  */
 207 static int
 208 gnutls_Send( void *p_session, const void *buf, int i_length )
 209 {
 210     int val;
 211     tls_session_sys_t *p_sys;
 212
 213     p_sys = (tls_session_sys_t *)(((tls_session_t *)p_session)->p_sys);
 214
 215     val = gnutls_record_send( p_sys->session, buf, i_length );
 216     return (val < 0) ? gnutls_Error ((vlc_object_t *)p_session, val) : val;
 217 }
 218
 219
 220 /**
 221  * Receives data through a TLS session.
 222  */
 223 static int
 224 gnutls_Recv( void *p_session, void *buf, int i_length )
 225 {
 226     int val;
 227     tls_session_sys_t *p_sys;
 228
 229     p_sys = (tls_session_sys_t *)(((tls_session_t *)p_session)->p_sys);
 230
 231     val = gnutls_record_recv( p_sys->session, buf, i_length );
 232     return (val < 0) ? gnutls_Error ((vlc_object_t *)p_session, val) : val;
 233 }
 234
 235
 236 /**
 237  * Starts or continues the TLS handshake.
 238  *
 239  * @return -1 on fatal error, 0 on successful handshake completion,
 240  * 1 if more would-be blocking recv is needed,
 241  * 2 if more would-be blocking send is required.
 242  */
 243 static int
 244 gnutls_ContinueHandshake (tls_session_t *p_session)
 245 {
 246     tls_session_sys_t *p_sys = p_session->p_sys;
 247     int val;
 248
 249 #ifdef WIN32
 250     WSASetLastError( 0 );
 251 #endif
 252     val = gnutls_handshake( p_sys->session );
 253     if( ( val == GNUTLS_E_AGAIN ) || ( val == GNUTLS_E_INTERRUPTED ) )
 254         return 1 + gnutls_record_get_direction( p_sys->session );
 255
 256     if( val < 0 )
 257     {
 258 #ifdef WIN32
 259         msg_Dbg( p_session, "Winsock error %d", WSAGetLastError( ) );
 260 #endif
 261         msg_Err( p_session, "TLS handshake error: %s",
 262                  gnutls_strerror( val ) );
 263         return -1;
 264     }
 265
 266     p_sys->b_handshaked = true;
 267     return 0;
 268 }
 269
 270
 271 typedef struct
 272 {
 273     int flag;
 274     const char *msg;
 275 } error_msg_t;
 276
 277 static const error_msg_t cert_errors[] =
 278 {
 279     { GNUTLS_CERT_INVALID,
 280         "Certificate could not be verified" },
 281     { GNUTLS_CERT_REVOKED,
 282         "Certificate was revoked" },
 283     { GNUTLS_CERT_SIGNER_NOT_FOUND,
 284         "Certificate's signer was not found" },
 285     { GNUTLS_CERT_SIGNER_NOT_CA,
 286         "Certificate's signer is not a CA" },
 287     { GNUTLS_CERT_INSECURE_ALGORITHM,
 288         "Insecure certificate signature algorithm" },
 289     { 0, NULL }
 290 };
 291
 292
 293 static int
 294 gnutls_HandshakeAndValidate( tls_session_t *session )
 295 {
 296     int val = gnutls_ContinueHandshake( session );
 297     if( val )
 298         return val;
 299
 300     tls_session_sys_t *p_sys = (tls_session_sys_t *)(session->p_sys);
 301
 302     /* certificates chain verification */
 303     unsigned status;
 304     val = gnutls_certificate_verify_peers2( p_sys->session, &status );
 305
 306     if( val )
 307     {
 308         msg_Err( session, "Certificate verification failed: %s",
 309                  gnutls_strerror( val ) );
 310         return -1;
 311     }
 312
 313     if( status )
 314     {
 315         msg_Err( session, "TLS session: access denied" );
 316         for( const error_msg_t *e = cert_errors; e->flag; e++ )
 317         {
 318             if( status & e->flag )
 319             {
 320                 msg_Err( session, "%s", e->msg );
 321                 status &= ~e->flag;
 322             }
 323         }
 324
 325         if( status )
 326             msg_Err( session,
 327                      "unknown certificate error (you found a bug in VLC)" );
 328
 329         return -1;
 330     }
 331
 332     /* certificate (host)name verification */
 333     const gnutls_datum_t *data;
 334     data = gnutls_certificate_get_peers (p_sys->session, &(unsigned){0});
 335     if( data == NULL )
 336     {
 337         msg_Err( session, "Peer certificate not available" );
 338         return -1;
 339     }
 340
 341     gnutls_x509_crt_t cert;
 342     val = gnutls_x509_crt_init( &cert );
 343     if( val )
 344     {
 345         msg_Err( session, "x509 fatal error: %s", gnutls_strerror( val ) );
 346         return -1;
 347     }
 348
 349     val = gnutls_x509_crt_import( cert, data, GNUTLS_X509_FMT_DER );
 350     if( val )
 351     {
 352         msg_Err( session, "Certificate import error: %s",
 353                  gnutls_strerror( val ) );
 354         goto error;
 355     }
 356
 357     assert( p_sys->psz_hostname != NULL );
 358     if ( !gnutls_x509_crt_check_hostname( cert, p_sys->psz_hostname ) )
 359     {
 360         msg_Err( session, "Certificate does not match \"%s\"",
 361                  p_sys->psz_hostname );
 362         goto error;
 363     }
 364
 365     if( gnutls_x509_crt_get_expiration_time( cert ) < time( NULL ) )
 366     {
 367         msg_Err( session, "Certificate expired" );
 368         goto error;
 369     }
 370
 371     if( gnutls_x509_crt_get_activation_time( cert ) > time ( NULL ) )
 372     {
 373         msg_Err( session, "Certificate not yet valid" );
 374         goto error;
 375     }
 376
 377     gnutls_x509_crt_deinit( cert );
 378     msg_Dbg( session, "TLS/x509 certificate verified" );
 379     return 0;
 380
 381 error:
 382     gnutls_x509_crt_deinit( cert );
 383     return -1;
 384 }
 385
 386 /**
 387  * Sets the operating system file descriptor backend for the TLS sesison.
 388  *
 389  * @param fd stream socket already connected with the peer.
 390  */
 391 static void
 392 gnutls_SetFD (tls_session_t *p_session, int fd)
 393 {
 394     gnutls_transport_set_ptr (p_session->p_sys->session,
 395                               (gnutls_transport_ptr_t)(intptr_t)fd);
 396 }
 397
 398 typedef int (*tls_prio_func) (gnutls_session_t, const int *);
 399
 400 static int
 401 gnutls_SetPriority (vlc_object_t *restrict obj, const char *restrict name,
 402                     tls_prio_func func, gnutls_session_t session,
 403                     const int *restrict values)
 404 {
 405     int val = func (session, values);
 406     if (val < 0)
 407     {
 408         msg_Err (obj, "cannot set %s priorities: %s", name,
 409                  gnutls_strerror (val));
 410         return VLC_EGENERIC;
 411     }
 412     return VLC_SUCCESS;
 413 }
 414
 415
 416 static int
 417 gnutls_SessionPrioritize (vlc_object_t *obj, gnutls_session_t session)
 418 {
 419     /* Note that ordering matters (on the client side) */
 420     static const int protos[] =
 421     {
 422         /*GNUTLS_TLS1_2, as of GnuTLS 2.6.5, still not ratified */
 423         GNUTLS_TLS1_1,
 424         GNUTLS_TLS1_0,
 425         GNUTLS_SSL3,
 426         0
 427     };
 428     static const int comps[] =
 429     {
 430         GNUTLS_COMP_DEFLATE,
 431         GNUTLS_COMP_NULL,
 432         0
 433     };
 434     static const int macs[] =
 435     {
 436         GNUTLS_MAC_SHA512,
 437         GNUTLS_MAC_SHA384,
 438         GNUTLS_MAC_SHA256,
 439         GNUTLS_MAC_SHA1,
 440         GNUTLS_MAC_RMD160, // RIPEMD
 441         GNUTLS_MAC_MD5,
 442         //GNUTLS_MAC_MD2,
 443         //GNUTLS_MAC_NULL,
 444         0
 445     };
 446     static const int ciphers[] =
 447     {
 448         GNUTLS_CIPHER_AES_256_CBC,
 449         GNUTLS_CIPHER_AES_128_CBC,
 450         GNUTLS_CIPHER_3DES_CBC,
 451         GNUTLS_CIPHER_ARCFOUR_128,
 452         // TODO? Camellia ciphers?
 453         //GNUTLS_CIPHER_DES_CBC,
 454         //GNUTLS_CIPHER_ARCFOUR_40,
 455         //GNUTLS_CIPHER_RC2_40_CBC,
 456         //GNUTLS_CIPHER_NULL,
 457         0
 458     };
 459     static const int kx[] =
 460     {
 461         GNUTLS_KX_DHE_RSA,
 462         GNUTLS_KX_DHE_DSS,
 463         GNUTLS_KX_RSA,
 464         //GNUTLS_KX_RSA_EXPORT,
 465         //GNUTLS_KX_DHE_PSK, TODO
 466         //GNUTLS_KX_PSK,     TODO
 467         //GNUTLS_KX_SRP_RSA, TODO
 468         //GNUTLS_KX_SRP_DSS, TODO
 469         //GNUTLS_KX_SRP,     TODO
 470         //GNUTLS_KX_ANON_DH,
 471         0
 472     };
 473     static const int cert_types[] =
 474     {
 475         GNUTLS_CRT_X509,
 476         //GNUTLS_CRT_OPENPGP, TODO
 477         0
 478     };
 479
 480     int val = gnutls_set_default_priority (session);
 481     if (val < 0)
 482     {
 483         msg_Err (obj, "cannot set default TLS priorities: %s",
 484                  gnutls_strerror (val));
 485         return VLC_EGENERIC;
 486     }
 487
 488     if (gnutls_SetPriority (obj, "protocols",
 489                             gnutls_protocol_set_priority, session, protos)
 490      || gnutls_SetPriority (obj, "compression algorithms",
 491                             gnutls_compression_set_priority, session, comps)
 492      || gnutls_SetPriority (obj, "MAC algorithms",
 493                             gnutls_mac_set_priority, session, macs)
 494      || gnutls_SetPriority (obj, "ciphers",
 495                             gnutls_cipher_set_priority, session, ciphers)
 496      || gnutls_SetPriority (obj, "key exchange algorithms",
 497                             gnutls_kx_set_priority, session, kx)
 498      || gnutls_SetPriority (obj, "certificate types",
 499                             gnutls_certificate_type_set_priority, session,
 500                             cert_types))
 501         return VLC_EGENERIC;
 502
 503     return VLC_SUCCESS;
 504 }
 505
 506
 507 static int
 508 gnutls_Addx509File( vlc_object_t *p_this,
 509                     gnutls_certificate_credentials_t cred,
 510                     const char *psz_path, bool b_priv );
 511
 512 static int
 513 gnutls_Addx509Directory( vlc_object_t *p_this,
 514                          gnutls_certificate_credentials_t cred,
 515                          const char *psz_dirname,
 516                          bool b_priv )
 517 {
 518     DIR* dir;
 519
 520     if( *psz_dirname == '\0' )
 521         psz_dirname = ".";
 522
 523     dir = vlc_opendir( psz_dirname );
 524     if( dir == NULL )
 525     {
 526         if (errno != ENOENT)
 527         {
 528             msg_Err (p_this, "cannot open directory (%s): %m", psz_dirname);
 529             return VLC_EGENERIC;
 530         }
 531
 532         msg_Dbg (p_this, "creating empty certificate directory: %s",
 533                  psz_dirname);
 534         vlc_mkdir (psz_dirname, b_priv ? 0700 : 0755);
 535         return VLC_SUCCESS;
 536     }
 537 #ifdef S_ISLNK
 538     else
 539     {
 540         struct stat st1, st2;
 541         int fd = dirfd( dir );
 542
 543         /*
 544          * Gets stats for the directory path, checks that it is not a
 545          * symbolic link (to avoid possibly infinite recursion), and verifies
 546          * that the inode is still the same, to avoid TOCTOU race condition.
 547          */
 548         if( ( fd == -1)
 549          || fstat( fd, &st1 ) || vlc_lstat( psz_dirname, &st2 )
 550          || S_ISLNK( st2.st_mode ) || ( st1.st_ino != st2.st_ino ) )
 551         {
 552             closedir( dir );
 553             return VLC_EGENERIC;
 554         }
 555     }
 556 #endif
 557
 558     for (;;)
 559     {
 560         char *ent = vlc_readdir (dir);
 561         if (ent == NULL)
 562             break;
 563
 564         if ((strcmp (ent, ".") == 0) || (strcmp (ent, "..") == 0))
 565         {
 566             free( ent );
 567             continue;
 568         }
 569
 570         char path[strlen (psz_dirname) + strlen (ent) + 2];
 571         sprintf (path, "%s"DIR_SEP"%s", psz_dirname, ent);
 572         free (ent);
 573
 574         gnutls_Addx509File( p_this, cred, path, b_priv );
 575     }
 576
 577     closedir( dir );
 578     return VLC_SUCCESS;
 579 }
 580
 581
 582 static int
 583 gnutls_Addx509File( vlc_object_t *p_this,
 584                     gnutls_certificate_credentials cred,
 585                     const char *psz_path, bool b_priv )
 586 {
 587     struct stat st;
 588
 589     int fd = vlc_open (psz_path, O_RDONLY);
 590     if (fd == -1)
 591         goto error;
 592
 593     block_t *block = block_File (fd);
 594     if (block != NULL)
 595     {
 596         close (fd);
 597
 598         gnutls_datum data = {
 599             .data = block->p_buffer,
 600             .size = block->i_buffer,
 601         };
 602         int res = b_priv
 603             ? gnutls_certificate_set_x509_key_mem (cred, &data, &data,
 604                                                    GNUTLS_X509_FMT_PEM)
 605             : gnutls_certificate_set_x509_trust_mem (cred, &data,
 606                                                      GNUTLS_X509_FMT_PEM);
 607         block_Release (block);
 608
 609         if (res < 0)
 610         {
 611             msg_Warn (p_this, "cannot add x509 credentials (%s): %s",
 612                       psz_path, gnutls_strerror (res));
 613             return VLC_EGENERIC;
 614         }
 615         msg_Dbg (p_this, "added x509 credentials (%s)", psz_path);
 616         return VLC_SUCCESS;
 617     }
 618
 619     if (!fstat (fd, &st) && S_ISDIR (st.st_mode))
 620     {
 621         close (fd);
 622         msg_Dbg (p_this, "looking recursively for x509 credentials in %s",
 623                  psz_path);
 624         return gnutls_Addx509Directory (p_this, cred, psz_path, b_priv);
 625     }
 626
 627 error:
 628     msg_Warn (p_this, "cannot add x509 credentials (%s): %m", psz_path);
 629     if (fd != -1)
 630         close (fd);
 631     return VLC_EGENERIC;
 632 }
 633
 634
 635 /** TLS client session data */
 636 typedef struct tls_client_sys_t
 637 {
 638     struct tls_session_sys_t         session;
 639     gnutls_certificate_credentials_t x509_cred;
 640 } tls_client_sys_t;
 641
 642
 643 /**
 644  * Initializes a client-side TLS session.
 645  */
 646 static int OpenClient (vlc_object_t *obj)
 647 {
 648     tls_session_t *p_session = (tls_session_t *)obj;
 649     int i_val;
 650
 651     if (gnutls_Init (obj))
 652         return VLC_EGENERIC;
 653
 654     tls_client_sys_t *p_sys = malloc (sizeof (*p_sys));
 655     if (p_sys == NULL)
 656     {
 657         gnutls_Deinit (obj);
 658         return VLC_ENOMEM;
 659     }
 660
 661     p_session->p_sys = &p_sys->session;
 662     p_session->sock.p_sys = p_session;
 663     p_session->sock.pf_send = gnutls_Send;
 664     p_session->sock.pf_recv = gnutls_Recv;
 665     p_session->pf_set_fd = gnutls_SetFD;
 666
 667     p_sys->session.b_handshaked = false;
 668
 669     i_val = gnutls_certificate_allocate_credentials (&p_sys->x509_cred);
 670     if (i_val != 0)
 671     {
 672         msg_Err (obj, "cannot allocate X509 credentials: %s",
 673                  gnutls_strerror (i_val));
 674         goto error;
 675     }
 676
 677     char *userdir = config_GetUserDir ( VLC_DATA_DIR );
 678     if (userdir != NULL)
 679     {
 680         char path[strlen (userdir) + sizeof ("/ssl/private")];
 681         sprintf (path, "%s/ssl", userdir);
 682         vlc_mkdir (path, 0755);
 683
 684         sprintf (path, "%s/ssl/certs", userdir);
 685         gnutls_Addx509Directory (VLC_OBJECT (p_session),
 686                                  p_sys->x509_cred, path, false);
 687         sprintf (path, "%s/ssl/private", userdir);
 688         gnutls_Addx509Directory (VLC_OBJECT (p_session), p_sys->x509_cred,
 689                                  path, true);
 690         free (userdir);
 691     }
 692
 693     const char *confdir = config_GetConfDir ();
 694     {
 695         char path[strlen (confdir)
 696                    + sizeof ("/ssl/certs/ca-certificates.crt")];
 697         sprintf (path, "%s/ssl/certs/ca-certificates.crt", confdir);
 698         gnutls_Addx509File (VLC_OBJECT (p_session),
 699                             p_sys->x509_cred, path, false);
 700     }
 701     p_session->pf_handshake = gnutls_HandshakeAndValidate;
 702     /*p_session->pf_handshake = gnutls_ContinueHandshake;*/
 703
 704     i_val = gnutls_init (&p_sys->session.session, GNUTLS_CLIENT);
 705     if (i_val != 0)
 706     {
 707         msg_Err (obj, "cannot initialize TLS session: %s",
 708                  gnutls_strerror (i_val));
 709         gnutls_certificate_free_credentials (p_sys->x509_cred);
 710         goto error;
 711     }
 712
 713     if (gnutls_SessionPrioritize (VLC_OBJECT (p_session),
 714                                   p_sys->session.session))
 715         goto s_error;
 716
 717     /* minimum DH prime bits */
 718     gnutls_dh_set_prime_bits (p_sys->session.session, 1024);
 719
 720     i_val = gnutls_credentials_set (p_sys->session.session,
 721                                     GNUTLS_CRD_CERTIFICATE,
 722                                     p_sys->x509_cred);
 723     if (i_val < 0)
 724     {
 725         msg_Err (obj, "cannot set TLS session credentials: %s",
 726                  gnutls_strerror (i_val));
 727         goto s_error;
 728     }
 729
 730     char *servername = var_GetNonEmptyString (p_session, "tls-server-name");
 731     if (servername == NULL )
 732         msg_Err (p_session, "server name missing for TLS session");
 733     else
 734         gnutls_server_name_set (p_sys->session.session, GNUTLS_NAME_DNS,
 735                                 servername, strlen (servername));
 736
 737     p_sys->session.psz_hostname = servername;
 738
 739     return VLC_SUCCESS;
 740
 741 s_error:
 742     gnutls_deinit (p_sys->session.session);
 743     gnutls_certificate_free_credentials (p_sys->x509_cred);
 744 error:
 745     gnutls_Deinit (obj);
 746     free (p_sys);
 747     return VLC_EGENERIC;
 748 }
 749
 750
 751 static void CloseClient (vlc_object_t *obj)
 752 {
 753     tls_session_t *client = (tls_session_t *)obj;
 754     tls_client_sys_t *p_sys = (tls_client_sys_t *)(client->p_sys);
 755
 756     if (p_sys->session.b_handshaked == true)
 757         gnutls_bye (p_sys->session.session, GNUTLS_SHUT_WR);
 758     gnutls_deinit (p_sys->session.session);
 759     /* credentials must be free'd *after* gnutls_deinit() */
 760     gnutls_certificate_free_credentials (p_sys->x509_cred);
 761
 762     gnutls_Deinit (obj);
 763     free (p_sys->session.psz_hostname);
 764     free (p_sys);
 765 }
 766
 767
 768 /**
 769  * Server-side TLS
 770  */
 771 struct tls_server_sys_t
 772 {
 773     gnutls_certificate_credentials_t x509_cred;
 774     gnutls_dh_params_t               dh_params;
 775
 776     struct saved_session_t          *p_cache;
 777     struct saved_session_t          *p_store;
 778     int                              i_cache_size;
 779     vlc_mutex_t                      cache_lock;
 780
 781     int                            (*pf_handshake) (tls_session_t *);
 782 };
 783
 784
 785 /**
 786  * TLS session resumption callbacks (server-side)
 787  */
 788 #define MAX_SESSION_ID    32
 789 #define MAX_SESSION_DATA  1024
 790
 791 typedef struct saved_session_t
 792 {
 793     char id[MAX_SESSION_ID];
 794     char data[MAX_SESSION_DATA];
 795
 796     unsigned i_idlen;
 797     unsigned i_datalen;
 798 } saved_session_t;
 799
 800
 801 static int cb_store( void *p_server, gnutls_datum key, gnutls_datum data )
 802 {
 803     tls_server_sys_t *p_sys = ((tls_server_t *)p_server)->p_sys;
 804
 805     if( ( p_sys->i_cache_size == 0 )
 806      || ( key.size > MAX_SESSION_ID )
 807      || ( data.size > MAX_SESSION_DATA ) )
 808         return -1;
 809
 810     vlc_mutex_lock( &p_sys->cache_lock );
 811
 812     memcpy( p_sys->p_store->id, key.data, key.size);
 813     memcpy( p_sys->p_store->data, data.data, data.size );
 814     p_sys->p_store->i_idlen = key.size;
 815     p_sys->p_store->i_datalen = data.size;
 816
 817     p_sys->p_store++;
 818     if( ( p_sys->p_store - p_sys->p_cache ) == p_sys->i_cache_size )
 819         p_sys->p_store = p_sys->p_cache;
 820
 821     vlc_mutex_unlock( &p_sys->cache_lock );
 822
 823     return 0;
 824 }
 825
 826
 827 static gnutls_datum cb_fetch( void *p_server, gnutls_datum key )
 828 {
 829     static const gnutls_datum_t err_datum = { NULL, 0 };
 830     tls_server_sys_t *p_sys = ((tls_server_t *)p_server)->p_sys;
 831     saved_session_t *p_session, *p_end;
 832
 833     p_session = p_sys->p_cache;
 834     p_end = p_session + p_sys->i_cache_size;
 835
 836     vlc_mutex_lock( &p_sys->cache_lock );
 837
 838     while( p_session < p_end )
 839     {
 840         if( ( p_session->i_idlen == key.size )
 841          && !memcmp( p_session->id, key.data, key.size ) )
 842         {
 843             gnutls_datum_t data;
 844
 845             data.size = p_session->i_datalen;
 846
 847             data.data = gnutls_malloc( data.size );
 848             if( data.data == NULL )
 849             {
 850                 vlc_mutex_unlock( &p_sys->cache_lock );
 851                 return err_datum;
 852             }
 853
 854             memcpy( data.data, p_session->data, data.size );
 855             vlc_mutex_unlock( &p_sys->cache_lock );
 856             return data;
 857         }
 858         p_session++;
 859     }
 860
 861     vlc_mutex_unlock( &p_sys->cache_lock );
 862
 863     return err_datum;
 864 }
 865
 866
 867 static int cb_delete( void *p_server, gnutls_datum key )
 868 {
 869     tls_server_sys_t *p_sys = ((tls_server_t *)p_server)->p_sys;
 870     saved_session_t *p_session, *p_end;
 871
 872     p_session = p_sys->p_cache;
 873     p_end = p_session + p_sys->i_cache_size;
 874
 875     vlc_mutex_lock( &p_sys->cache_lock );
 876
 877     while( p_session < p_end )
 878     {
 879         if( ( p_session->i_idlen == key.size )
 880          && !memcmp( p_session->id, key.data, key.size ) )
 881         {
 882             p_session->i_datalen = p_session->i_idlen = 0;
 883             vlc_mutex_unlock( &p_sys->cache_lock );
 884             return 0;
 885         }
 886         p_session++;
 887     }
 888
 889     vlc_mutex_unlock( &p_sys->cache_lock );
 890
 891     return -1;
 892 }
 893
 894
 895 /**
 896  * Terminates TLS session and releases session data.
 897  * You still have to close the socket yourself.
 898  */
 899 static void
 900 gnutls_SessionClose (tls_server_t *p_server, tls_session_t *p_session)
 901 {
 902     tls_session_sys_t *p_sys = p_session->p_sys;
 903     (void)p_server;
 904
 905     if( p_sys->b_handshaked == true )
 906         gnutls_bye( p_sys->session, GNUTLS_SHUT_WR );
 907     gnutls_deinit( p_sys->session );
 908
 909     vlc_object_release( p_session );
 910
 911     free( p_sys );
 912 }
 913
 914
 915 /**
 916  * Initializes a server-side TLS session.
 917  */
 918 static tls_session_t *
 919 gnutls_ServerSessionPrepare( tls_server_t *p_server )
 920 {
 921     tls_session_t *p_session;
 922     tls_server_sys_t *p_server_sys;
 923     gnutls_session_t session;
 924     int i_val;
 925
 926     p_session = vlc_object_create( p_server, sizeof (struct tls_session_t) );
 927     if( p_session == NULL )
 928         return NULL;
 929
 930     p_session->p_sys = malloc( sizeof(struct tls_session_sys_t) );
 931     if( p_session->p_sys == NULL )
 932     {
 933         vlc_object_release( p_session );
 934         return NULL;
 935     }
 936
 937     p_server_sys = p_server->p_sys;
 938     p_session->sock.p_sys = p_session;
 939     p_session->sock.pf_send = gnutls_Send;
 940     p_session->sock.pf_recv = gnutls_Recv;
 941     p_session->pf_set_fd = gnutls_SetFD;
 942     p_session->pf_handshake = p_server_sys->pf_handshake;
 943
 944     p_session->p_sys->b_handshaked = false;
 945     p_session->p_sys->psz_hostname = NULL;
 946
 947     i_val = gnutls_init( &session, GNUTLS_SERVER );
 948     if( i_val != 0 )
 949     {
 950         msg_Err( p_server, "cannot initialize TLS session: %s",
 951                  gnutls_strerror( i_val ) );
 952         goto error;
 953     }
 954
 955     p_session->p_sys->session = session;
 956
 957     if (gnutls_SessionPrioritize (VLC_OBJECT (p_session), session))
 958     {
 959         gnutls_deinit( session );
 960         goto error;
 961     }
 962
 963     i_val = gnutls_credentials_set( session, GNUTLS_CRD_CERTIFICATE,
 964                                     p_server_sys->x509_cred );
 965     if( i_val < 0 )
 966     {
 967         msg_Err( p_server, "cannot set TLS session credentials: %s",
 968                  gnutls_strerror( i_val ) );
 969         gnutls_deinit( session );
 970         goto error;
 971     }
 972
 973     if (p_session->pf_handshake == gnutls_HandshakeAndValidate)
 974         gnutls_certificate_server_set_request (session, GNUTLS_CERT_REQUIRE);
 975
 976     /* Session resumption support */
 977     i_val = var_InheritInteger (p_server, "gnutls-cache-timeout");
 978     if (i_val >= 0)
 979         gnutls_db_set_cache_expiration (session, i_val);
 980     gnutls_db_set_retrieve_function( session, cb_fetch );
 981     gnutls_db_set_remove_function( session, cb_delete );
 982     gnutls_db_set_store_function( session, cb_store );
 983     gnutls_db_set_ptr( session, p_server );
 984
 985     return p_session;
 986
 987 error:
 988     free( p_session->p_sys );
 989     vlc_object_release( p_session );
 990     return NULL;
 991 }
 992
 993
 994 /**
 995  * Adds one or more certificate authorities.
 996  *
 997  * @param psz_ca_path (Unicode) path to an x509 certificates list.
 998  *
 999  * @return -1 on error, 0 on success.
1000  */
1001 static int
1002 gnutls_ServerAddCA( tls_server_t *p_server, const char *psz_ca_path )
1003 {
1004     tls_server_sys_t *p_sys;
1005     char *psz_local_path;
1006     int val;
1007
1008     p_sys = (tls_server_sys_t *)(p_server->p_sys);
1009
1010     psz_local_path = ToLocale( psz_ca_path );
1011     val = gnutls_certificate_set_x509_trust_file( p_sys->x509_cred,
1012                                                   psz_local_path,
1013                                                   GNUTLS_X509_FMT_PEM );
1014     LocaleFree( psz_local_path );
1015     if( val < 0 )
1016     {
1017         msg_Err( p_server, "cannot add trusted CA (%s): %s", psz_ca_path,
1018                  gnutls_strerror( val ) );
1019         return VLC_EGENERIC;
1020     }
1021     msg_Dbg( p_server, " %d trusted CA added (%s)", val, psz_ca_path );
1022
1023     /* enables peer's certificate verification */
1024     p_sys->pf_handshake = gnutls_HandshakeAndValidate;
1025
1026     return VLC_SUCCESS;
1027 }
1028
1029
1030 /**
1031  * Adds a certificates revocation list to be sent to TLS clients.
1032  *
1033  * @param psz_crl_path (Unicode) path of the CRL file.
1034  *
1035  * @return -1 on error, 0 on success.
1036  */
1037 static int
1038 gnutls_ServerAddCRL( tls_server_t *p_server, const char *psz_crl_path )
1039 {
1040     int val;
1041     char *psz_local_path = ToLocale( psz_crl_path );
1042
1043     val = gnutls_certificate_set_x509_crl_file( ((tls_server_sys_t *)
1044                                                 (p_server->p_sys))->x509_cred,
1045                                                 psz_local_path,
1046                                                 GNUTLS_X509_FMT_PEM );
1047     LocaleFree( psz_crl_path );
1048     if( val < 0 )
1049     {
1050         msg_Err( p_server, "cannot add CRL (%s): %s", psz_crl_path,
1051                  gnutls_strerror( val ) );
1052         return VLC_EGENERIC;
1053     }
1054     msg_Dbg( p_server, "%d CRL added (%s)", val, psz_crl_path );
1055     return VLC_SUCCESS;
1056 }
1057
1058
1059 /**
1060  * Allocates a whole server's TLS credentials.
1061  */
1062 static int OpenServer (vlc_object_t *obj)
1063 {
1064     tls_server_t *p_server = (tls_server_t *)obj;
1065     tls_server_sys_t *p_sys;
1066     int val;
1067
1068     if (gnutls_Init (obj))
1069         return VLC_EGENERIC;
1070
1071     msg_Dbg (obj, "creating TLS server");
1072
1073     p_sys = (tls_server_sys_t *)malloc( sizeof(struct tls_server_sys_t) );
1074     if( p_sys == NULL )
1075         return VLC_ENOMEM;
1076
1077     p_sys->i_cache_size = var_InheritInteger (obj, "gnutls-cache-size");
1078     if (p_sys->i_cache_size == -1) /* Duh, config subsystem exploded?! */
1079         p_sys->i_cache_size = 0;
1080     p_sys->p_cache = calloc (p_sys->i_cache_size,
1081                              sizeof (struct saved_session_t));
1082     if (p_sys->p_cache == NULL)
1083     {
1084         free (p_sys);
1085         return VLC_ENOMEM;
1086     }
1087
1088     p_sys->p_store = p_sys->p_cache;
1089     p_server->p_sys = p_sys;
1090     p_server->pf_add_CA  = gnutls_ServerAddCA;
1091     p_server->pf_add_CRL = gnutls_ServerAddCRL;
1092     p_server->pf_open    = gnutls_ServerSessionPrepare;
1093     p_server->pf_close   = gnutls_SessionClose;
1094
1095     /* No certificate validation by default */
1096     p_sys->pf_handshake  = gnutls_ContinueHandshake;
1097
1098     vlc_mutex_init( &p_sys->cache_lock );
1099
1100     /* Sets server's credentials */
1101     val = gnutls_certificate_allocate_credentials( &p_sys->x509_cred );
1102     if( val != 0 )
1103     {
1104         msg_Err( p_server, "cannot allocate X509 credentials: %s",
1105                  gnutls_strerror( val ) );
1106         goto error;
1107     }
1108
1109     char *psz_cert_path = var_GetNonEmptyString (obj, "tls-x509-cert");
1110     char *psz_key_path = var_GetNonEmptyString (obj, "tls-x509-key");
1111     const char *psz_local_cert = ToLocale (psz_cert_path);
1112     const char *psz_local_key = ToLocale (psz_key_path);
1113     val = gnutls_certificate_set_x509_key_file (p_sys->x509_cred,
1114                                                 psz_local_cert, psz_local_key,
1115                                                 GNUTLS_X509_FMT_PEM );
1116     LocaleFree (psz_local_key);
1117     free (psz_key_path);
1118     LocaleFree (psz_local_cert);
1119     free (psz_cert_path);
1120
1121     if( val < 0 )
1122     {
1123         msg_Err( p_server, "cannot set certificate chain or private key: %s",
1124                  gnutls_strerror( val ) );
1125         gnutls_certificate_free_credentials( p_sys->x509_cred );
1126         goto error;
1127     }
1128
1129     /* FIXME:
1130      * - support other ciper suites
1131      */
1132     val = gnutls_dh_params_init (&p_sys->dh_params);
1133     if (val >= 0)
1134     {
1135         const gnutls_datum_t data = {
1136             .data = (unsigned char *)dh_params,
1137             .size = sizeof (dh_params) - 1,
1138         };
1139
1140         val = gnutls_dh_params_import_pkcs3 (p_sys->dh_params, &data,
1141                                              GNUTLS_X509_FMT_PEM);
1142         if (val == 0)
1143             gnutls_certificate_set_dh_params (p_sys->x509_cred,
1144                                               p_sys->dh_params);
1145     }
1146     if (val < 0)
1147     {
1148         msg_Err (p_server, "cannot initialize DHE cipher suites: %s",
1149                  gnutls_strerror (val));
1150     }
1151
1152     return VLC_SUCCESS;
1153
1154 error:
1155     vlc_mutex_destroy (&p_sys->cache_lock);
1156     free (p_sys->p_cache);
1157     free (p_sys);
1158     return VLC_EGENERIC;
1159 }
1160
1161 /**
1162  * Destroys a TLS server object.
1163  */
1164 static void CloseServer (vlc_object_t *p_server)
1165 {
1166     tls_server_sys_t *p_sys = ((tls_server_t *)p_server)->p_sys;
1167
1168     vlc_mutex_destroy (&p_sys->cache_lock);
1169     free (p_sys->p_cache);
1170
1171     /* all sessions depending on the server are now deinitialized */
1172     gnutls_certificate_free_credentials (p_sys->x509_cred);
1173     gnutls_dh_params_deinit (p_sys->dh_params);
1174     free (p_sys);
1175
1176     gnutls_Deinit (p_server);
1177 }