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_DIRENT_H
  40 # include <dirent.h>
  41 #endif
  42 #ifdef HAVE_SYS_STAT_H
  43 # include <sys/stat.h>
  44 #endif
  45 #ifdef WIN32
  46 # include <io.h>
  47 #else
  48 # include <unistd.h>
  49 #endif
  50 # include <fcntl.h>
  51
  52
  53 #include <vlc_tls.h>
  54 #include <vlc_charset.h>
  55 #include <vlc_fs.h>
  56 #include <vlc_block.h>
  57
  58 #include <gcrypt.h>
  59 #include <gnutls/gnutls.h>
  60 #include <gnutls/x509.h>
  61
  62 #include <vlc_gcrypt.h>
  63
  64 #define CACHE_TIMEOUT     3600
  65 #define CACHE_SIZE          64
  66
  67 #include "dhparams.h"
  68
  69 #include <assert.h>
  70
  71 /*****************************************************************************
  72  * Module descriptor
  73  *****************************************************************************/
  74 static int  OpenClient  (vlc_object_t *);
  75 static void CloseClient (vlc_object_t *);
  76 static int  OpenServer  (vlc_object_t *);
  77 static void CloseServer (vlc_object_t *);
  78
  79 #define CACHE_TIMEOUT_TEXT N_("Expiration time for resumed TLS sessions")
  80 #define CACHE_TIMEOUT_LONGTEXT N_( \
  81     "It is possible to cache the resumed TLS sessions. This is the expiration "\
  82     "time of the sessions stored in this cache, in seconds." )
  83
  84 #define CACHE_SIZE_TEXT N_("Number of resumed TLS sessions")
  85 #define CACHE_SIZE_LONGTEXT N_( \
  86     "This is the maximum number of resumed TLS sessions that " \
  87     "the cache will hold." )
  88
  89 vlc_module_begin ()
  90     set_shortname( "GnuTLS" )
  91     set_description( N_("GnuTLS transport layer security") )
  92     set_capability( "tls client", 1 )
  93     set_callbacks( OpenClient, CloseClient )
  94     set_category( CAT_ADVANCED )
  95     set_subcategory( SUBCAT_ADVANCED_MISC )
  96
  97     add_obsolete_bool( "tls-check-cert" )
  98     add_obsolete_bool( "tls-check-hostname" )
  99
 100     add_submodule ()
 101         set_description( N_("GnuTLS server") )
 102         set_capability( "tls server", 1 )
 103         set_category( CAT_ADVANCED )
 104         set_subcategory( SUBCAT_ADVANCED_MISC )
 105         set_callbacks( OpenServer, CloseServer )
 106
 107         add_obsolete_integer( "gnutls-dh-bits" )
 108         add_integer( "gnutls-cache-timeout", CACHE_TIMEOUT, NULL,
 109                     CACHE_TIMEOUT_TEXT, CACHE_TIMEOUT_LONGTEXT, true )
 110         add_integer( "gnutls-cache-size", CACHE_SIZE, NULL, CACHE_SIZE_TEXT,
 111                     CACHE_SIZE_LONGTEXT, true )
 112 vlc_module_end ()
 113
 114 static vlc_mutex_t gnutls_mutex = VLC_STATIC_MUTEX;
 115
 116 /**
 117  * Initializes GnuTLS with proper locking.
 118  * @return VLC_SUCCESS on success, a VLC error code otherwise.
 119  */
 120 static int gnutls_Init (vlc_object_t *p_this)
 121 {
 122     int ret = VLC_EGENERIC;
 123
 124     vlc_gcrypt_init (); /* GnuTLS depends on gcrypt */
 125
 126     vlc_mutex_lock (&gnutls_mutex);
 127     if (gnutls_global_init ())
 128     {
 129         msg_Err (p_this, "cannot initialize GnuTLS");
 130         goto error;
 131     }
 132
 133     const char *psz_version = gnutls_check_version ("1.3.3");
 134     if (psz_version == NULL)
 135     {
 136         msg_Err (p_this, "unsupported GnuTLS version");
 137         gnutls_global_deinit ();
 138         goto error;
 139     }
 140
 141     msg_Dbg (p_this, "GnuTLS v%s initialized", psz_version);
 142     ret = VLC_SUCCESS;
 143
 144 error:
 145     vlc_mutex_unlock (&gnutls_mutex);
 146     return ret;
 147 }
 148
 149
 150 /**
 151  * Deinitializes GnuTLS.
 152  */
 153 static void gnutls_Deinit (vlc_object_t *p_this)
 154 {
 155     vlc_mutex_lock (&gnutls_mutex);
 156
 157     gnutls_global_deinit ();
 158     msg_Dbg (p_this, "GnuTLS deinitialized");
 159     vlc_mutex_unlock (&gnutls_mutex);
 160 }
 161
 162
 163 static int gnutls_Error (vlc_object_t *obj, int val)
 164 {
 165     switch (val)
 166     {
 167         case GNUTLS_E_AGAIN:
 168 #ifdef WIN32
 169             WSASetLastError (WSAEWOULDBLOCK);
 170 #else
 171             errno = EAGAIN;
 172 #endif
 173             break;
 174
 175         case GNUTLS_E_INTERRUPTED:
 176 #ifdef WIN32
 177             WSASetLastError (WSAEINTR);
 178 #else
 179             errno = EINTR;
 180 #endif
 181             break;
 182
 183         default:
 184             msg_Err (obj, "%s", gnutls_strerror (val));
 185 #ifndef NDEBUG
 186             if (!gnutls_error_is_fatal (val))
 187                 msg_Err (obj, "Error above should be handled");
 188 #endif
 189 #ifdef WIN32
 190             WSASetLastError (WSAECONNRESET);
 191 #else
 192             errno = ECONNRESET;
 193 #endif
 194     }
 195     return -1;
 196 }
 197
 198
 199 struct tls_session_sys_t
 200 {
 201     gnutls_session_t session;
 202     char            *psz_hostname;
 203     bool       b_handshaked;
 204 };
 205
 206
 207 /**
 208  * Sends data through a TLS session.
 209  */
 210 static int
 211 gnutls_Send( void *p_session, const void *buf, int i_length )
 212 {
 213     int val;
 214     tls_session_sys_t *p_sys;
 215
 216     p_sys = (tls_session_sys_t *)(((tls_session_t *)p_session)->p_sys);
 217
 218     val = gnutls_record_send( p_sys->session, buf, i_length );
 219     return (val < 0) ? gnutls_Error ((vlc_object_t *)p_session, val) : val;
 220 }
 221
 222
 223 /**
 224  * Receives data through a TLS session.
 225  */
 226 static int
 227 gnutls_Recv( void *p_session, void *buf, int i_length )
 228 {
 229     int val;
 230     tls_session_sys_t *p_sys;
 231
 232     p_sys = (tls_session_sys_t *)(((tls_session_t *)p_session)->p_sys);
 233
 234     val = gnutls_record_recv( p_sys->session, buf, i_length );
 235     return (val < 0) ? gnutls_Error ((vlc_object_t *)p_session, val) : val;
 236 }
 237
 238
 239 /**
 240  * Starts or continues the TLS handshake.
 241  *
 242  * @return -1 on fatal error, 0 on successful handshake completion,
 243  * 1 if more would-be blocking recv is needed,
 244  * 2 if more would-be blocking send is required.
 245  */
 246 static int
 247 gnutls_ContinueHandshake (tls_session_t *p_session)
 248 {
 249     tls_session_sys_t *p_sys = p_session->p_sys;
 250     int val;
 251
 252 #ifdef WIN32
 253     WSASetLastError( 0 );
 254 #endif
 255     val = gnutls_handshake( p_sys->session );
 256     if( ( val == GNUTLS_E_AGAIN ) || ( val == GNUTLS_E_INTERRUPTED ) )
 257         return 1 + gnutls_record_get_direction( p_sys->session );
 258
 259     if( val < 0 )
 260     {
 261 #ifdef WIN32
 262         msg_Dbg( p_session, "Winsock error %d", WSAGetLastError( ) );
 263 #endif
 264         msg_Err( p_session, "TLS handshake error: %s",
 265                  gnutls_strerror( val ) );
 266         return -1;
 267     }
 268
 269     p_sys->b_handshaked = true;
 270     return 0;
 271 }
 272
 273
 274 typedef struct
 275 {
 276     int flag;
 277     const char *msg;
 278 } error_msg_t;
 279
 280 static const error_msg_t cert_errors[] =
 281 {
 282     { GNUTLS_CERT_INVALID,
 283         "Certificate could not be verified" },
 284     { GNUTLS_CERT_REVOKED,
 285         "Certificate was revoked" },
 286     { GNUTLS_CERT_SIGNER_NOT_FOUND,
 287         "Certificate's signer was not found" },
 288     { GNUTLS_CERT_SIGNER_NOT_CA,
 289         "Certificate's signer is not a CA" },
 290     { GNUTLS_CERT_INSECURE_ALGORITHM,
 291         "Insecure certificate signature algorithm" },
 292     { 0, NULL }
 293 };
 294
 295
 296 static int
 297 gnutls_HandshakeAndValidate( tls_session_t *session )
 298 {
 299     int val = gnutls_ContinueHandshake( session );
 300     if( val )
 301         return val;
 302
 303     tls_session_sys_t *p_sys = (tls_session_sys_t *)(session->p_sys);
 304
 305     /* certificates chain verification */
 306     unsigned status;
 307     val = gnutls_certificate_verify_peers2( p_sys->session, &status );
 308
 309     if( val )
 310     {
 311         msg_Err( session, "Certificate verification failed: %s",
 312                  gnutls_strerror( val ) );
 313         return -1;
 314     }
 315
 316     if( status )
 317     {
 318         msg_Err( session, "TLS session: access denied" );
 319         for( const error_msg_t *e = cert_errors; e->flag; e++ )
 320         {
 321             if( status & e->flag )
 322             {
 323                 msg_Err( session, "%s", e->msg );
 324                 status &= ~e->flag;
 325             }
 326         }
 327
 328         if( status )
 329             msg_Err( session,
 330                      "unknown certificate error (you found a bug in VLC)" );
 331
 332         return -1;
 333     }
 334
 335     /* certificate (host)name verification */
 336     const gnutls_datum_t *data;
 337     data = gnutls_certificate_get_peers (p_sys->session, &(unsigned){0});
 338     if( data == NULL )
 339     {
 340         msg_Err( session, "Peer certificate not available" );
 341         return -1;
 342     }
 343
 344     gnutls_x509_crt_t cert;
 345     val = gnutls_x509_crt_init( &cert );
 346     if( val )
 347     {
 348         msg_Err( session, "x509 fatal error: %s", gnutls_strerror( val ) );
 349         return -1;
 350     }
 351
 352     val = gnutls_x509_crt_import( cert, data, GNUTLS_X509_FMT_DER );
 353     if( val )
 354     {
 355         msg_Err( session, "Certificate import error: %s",
 356                  gnutls_strerror( val ) );
 357         goto error;
 358     }
 359
 360     assert( p_sys->psz_hostname != NULL );
 361     if ( !gnutls_x509_crt_check_hostname( cert, p_sys->psz_hostname ) )
 362     {
 363         msg_Err( session, "Certificate does not match \"%s\"",
 364                  p_sys->psz_hostname );
 365         goto error;
 366     }
 367
 368     if( gnutls_x509_crt_get_expiration_time( cert ) < time( NULL ) )
 369     {
 370         msg_Err( session, "Certificate expired" );
 371         goto error;
 372     }
 373
 374     if( gnutls_x509_crt_get_activation_time( cert ) > time ( NULL ) )
 375     {
 376         msg_Err( session, "Certificate not yet valid" );
 377         goto error;
 378     }
 379
 380     gnutls_x509_crt_deinit( cert );
 381     msg_Dbg( session, "TLS/x509 certificate verified" );
 382     return 0;
 383
 384 error:
 385     gnutls_x509_crt_deinit( cert );
 386     return -1;
 387 }
 388
 389 /**
 390  * Sets the operating system file descriptor backend for the TLS sesison.
 391  *
 392  * @param fd stream socket already connected with the peer.
 393  */
 394 static void
 395 gnutls_SetFD (tls_session_t *p_session, int fd)
 396 {
 397     gnutls_transport_set_ptr (p_session->p_sys->session,
 398                               (gnutls_transport_ptr_t)(intptr_t)fd);
 399 }
 400
 401 typedef int (*tls_prio_func) (gnutls_session_t, const int *);
 402
 403 static int
 404 gnutls_SetPriority (vlc_object_t *restrict obj, const char *restrict name,
 405                     tls_prio_func func, gnutls_session_t session,
 406                     const int *restrict values)
 407 {
 408     int val = func (session, values);
 409     if (val < 0)
 410     {
 411         msg_Err (obj, "cannot set %s priorities: %s", name,
 412                  gnutls_strerror (val));
 413         return VLC_EGENERIC;
 414     }
 415     return VLC_SUCCESS;
 416 }
 417
 418
 419 static int
 420 gnutls_SessionPrioritize (vlc_object_t *obj, gnutls_session_t session)
 421 {
 422     /* Note that ordering matters (on the client side) */
 423     static const int protos[] =
 424     {
 425         /*GNUTLS_TLS1_2, as of GnuTLS 2.6.5, still not ratified */
 426         GNUTLS_TLS1_1,
 427         GNUTLS_TLS1_0,
 428         GNUTLS_SSL3,
 429         0
 430     };
 431     static const int comps[] =
 432     {
 433         GNUTLS_COMP_DEFLATE,
 434         GNUTLS_COMP_NULL,
 435         0
 436     };
 437     static const int macs[] =
 438     {
 439         GNUTLS_MAC_SHA512,
 440         GNUTLS_MAC_SHA384,
 441         GNUTLS_MAC_SHA256,
 442         GNUTLS_MAC_SHA1,
 443         GNUTLS_MAC_RMD160, // RIPEMD
 444         GNUTLS_MAC_MD5,
 445         //GNUTLS_MAC_MD2,
 446         //GNUTLS_MAC_NULL,
 447         0
 448     };
 449     static const int ciphers[] =
 450     {
 451         GNUTLS_CIPHER_AES_256_CBC,
 452         GNUTLS_CIPHER_AES_128_CBC,
 453         GNUTLS_CIPHER_3DES_CBC,
 454         GNUTLS_CIPHER_ARCFOUR_128,
 455         // TODO? Camellia ciphers?
 456         //GNUTLS_CIPHER_DES_CBC,
 457         //GNUTLS_CIPHER_ARCFOUR_40,
 458         //GNUTLS_CIPHER_RC2_40_CBC,
 459         //GNUTLS_CIPHER_NULL,
 460         0
 461     };
 462     static const int kx[] =
 463     {
 464         GNUTLS_KX_DHE_RSA,
 465         GNUTLS_KX_DHE_DSS,
 466         GNUTLS_KX_RSA,
 467         //GNUTLS_KX_RSA_EXPORT,
 468         //GNUTLS_KX_DHE_PSK, TODO
 469         //GNUTLS_KX_PSK,     TODO
 470         //GNUTLS_KX_SRP_RSA, TODO
 471         //GNUTLS_KX_SRP_DSS, TODO
 472         //GNUTLS_KX_SRP,     TODO
 473         //GNUTLS_KX_ANON_DH,
 474         0
 475     };
 476     static const int cert_types[] =
 477     {
 478         GNUTLS_CRT_X509,
 479         //GNUTLS_CRT_OPENPGP, TODO
 480         0
 481     };
 482
 483     int val = gnutls_set_default_priority (session);
 484     if (val < 0)
 485     {
 486         msg_Err (obj, "cannot set default TLS priorities: %s",
 487                  gnutls_strerror (val));
 488         return VLC_EGENERIC;
 489     }
 490
 491     if (gnutls_SetPriority (obj, "protocols",
 492                             gnutls_protocol_set_priority, session, protos)
 493      || gnutls_SetPriority (obj, "compression algorithms",
 494                             gnutls_compression_set_priority, session, comps)
 495      || gnutls_SetPriority (obj, "MAC algorithms",
 496                             gnutls_mac_set_priority, session, macs)
 497      || gnutls_SetPriority (obj, "ciphers",
 498                             gnutls_cipher_set_priority, session, ciphers)
 499      || gnutls_SetPriority (obj, "key exchange algorithms",
 500                             gnutls_kx_set_priority, session, kx)
 501      || gnutls_SetPriority (obj, "certificate types",
 502                             gnutls_certificate_type_set_priority, session,
 503                             cert_types))
 504         return VLC_EGENERIC;
 505
 506     return VLC_SUCCESS;
 507 }
 508
 509
 510 static int
 511 gnutls_Addx509File( vlc_object_t *p_this,
 512                     gnutls_certificate_credentials_t cred,
 513                     const char *psz_path, bool b_priv );
 514
 515 static int
 516 gnutls_Addx509Directory( vlc_object_t *p_this,
 517                          gnutls_certificate_credentials_t cred,
 518                          const char *psz_dirname,
 519                          bool b_priv )
 520 {
 521     DIR* dir;
 522
 523     if( *psz_dirname == '\0' )
 524         psz_dirname = ".";
 525
 526     dir = vlc_opendir( psz_dirname );
 527     if( dir == NULL )
 528     {
 529         if (errno != ENOENT)
 530         {
 531             msg_Err (p_this, "cannot open directory (%s): %m", psz_dirname);
 532             return VLC_EGENERIC;
 533         }
 534
 535         msg_Dbg (p_this, "creating empty certificate directory: %s",
 536                  psz_dirname);
 537         vlc_mkdir (psz_dirname, b_priv ? 0700 : 0755);
 538         return VLC_SUCCESS;
 539     }
 540 #ifdef S_ISLNK
 541     else
 542     {
 543         struct stat st1, st2;
 544         int fd = dirfd( dir );
 545
 546         /*
 547          * Gets stats for the directory path, checks that it is not a
 548          * symbolic link (to avoid possibly infinite recursion), and verifies
 549          * that the inode is still the same, to avoid TOCTOU race condition.
 550          */
 551         if( ( fd == -1)
 552          || fstat( fd, &st1 ) || vlc_lstat( psz_dirname, &st2 )
 553          || S_ISLNK( st2.st_mode ) || ( st1.st_ino != st2.st_ino ) )
 554         {
 555             closedir( dir );
 556             return VLC_EGENERIC;
 557         }
 558     }
 559 #endif
 560
 561     for (;;)
 562     {
 563         char *ent = vlc_readdir (dir);
 564         if (ent == NULL)
 565             break;
 566
 567         if ((strcmp (ent, ".") == 0) || (strcmp (ent, "..") == 0))
 568         {
 569             free( ent );
 570             continue;
 571         }
 572
 573         char path[strlen (psz_dirname) + strlen (ent) + 2];
 574         sprintf (path, "%s"DIR_SEP"%s", psz_dirname, ent);
 575         free (ent);
 576
 577         gnutls_Addx509File( p_this, cred, path, b_priv );
 578     }
 579
 580     closedir( dir );
 581     return VLC_SUCCESS;
 582 }
 583
 584
 585 static int
 586 gnutls_Addx509File( vlc_object_t *p_this,
 587                     gnutls_certificate_credentials cred,
 588                     const char *psz_path, bool b_priv )
 589 {
 590     struct stat st;
 591
 592     int fd = vlc_open (psz_path, O_RDONLY);
 593     if (fd == -1)
 594         goto error;
 595
 596     block_t *block = block_File (fd);
 597     if (block != NULL)
 598     {
 599         close (fd);
 600
 601         gnutls_datum data = {
 602             .data = block->p_buffer,
 603             .size = block->i_buffer,
 604         };
 605         int res = b_priv
 606             ? gnutls_certificate_set_x509_key_mem (cred, &data, &data,
 607                                                    GNUTLS_X509_FMT_PEM)
 608             : gnutls_certificate_set_x509_trust_mem (cred, &data,
 609                                                      GNUTLS_X509_FMT_PEM);
 610         block_Release (block);
 611
 612         if (res < 0)
 613         {
 614             msg_Warn (p_this, "cannot add x509 credentials (%s): %s",
 615                       psz_path, gnutls_strerror (res));
 616             return VLC_EGENERIC;
 617         }
 618         msg_Dbg (p_this, "added x509 credentials (%s)", psz_path);
 619         return VLC_SUCCESS;
 620     }
 621
 622     if (!fstat (fd, &st) && S_ISDIR (st.st_mode))
 623     {
 624         close (fd);
 625         msg_Dbg (p_this, "looking recursively for x509 credentials in %s",
 626                  psz_path);
 627         return gnutls_Addx509Directory (p_this, cred, psz_path, b_priv);
 628     }
 629
 630 error:
 631     msg_Warn (p_this, "cannot add x509 credentials (%s): %m", psz_path);
 632     if (fd != -1)
 633         close (fd);
 634     return VLC_EGENERIC;
 635 }
 636
 637
 638 /** TLS client session data */
 639 typedef struct tls_client_sys_t
 640 {
 641     struct tls_session_sys_t         session;
 642     gnutls_certificate_credentials_t x509_cred;
 643 } tls_client_sys_t;
 644
 645
 646 /**
 647  * Initializes a client-side TLS session.
 648  */
 649 static int OpenClient (vlc_object_t *obj)
 650 {
 651     tls_session_t *p_session = (tls_session_t *)obj;
 652     int i_val;
 653
 654     if (gnutls_Init (obj))
 655         return VLC_EGENERIC;
 656
 657     tls_client_sys_t *p_sys = malloc (sizeof (*p_sys));
 658     if (p_sys == NULL)
 659     {
 660         gnutls_Deinit (obj);
 661         return VLC_ENOMEM;
 662     }
 663
 664     p_session->p_sys = &p_sys->session;
 665     p_session->sock.p_sys = p_session;
 666     p_session->sock.pf_send = gnutls_Send;
 667     p_session->sock.pf_recv = gnutls_Recv;
 668     p_session->pf_set_fd = gnutls_SetFD;
 669
 670     p_sys->session.b_handshaked = false;
 671
 672     i_val = gnutls_certificate_allocate_credentials (&p_sys->x509_cred);
 673     if (i_val != 0)
 674     {
 675         msg_Err (obj, "cannot allocate X509 credentials: %s",
 676                  gnutls_strerror (i_val));
 677         goto error;
 678     }
 679
 680     char *userdir = config_GetUserDir ( VLC_DATA_DIR );
 681     if (userdir != NULL)
 682     {
 683         char path[strlen (userdir) + sizeof ("/ssl/private")];
 684         sprintf (path, "%s/ssl", userdir);
 685         vlc_mkdir (path, 0755);
 686
 687         sprintf (path, "%s/ssl/certs", userdir);
 688         gnutls_Addx509Directory (VLC_OBJECT (p_session),
 689                                  p_sys->x509_cred, path, false);
 690         sprintf (path, "%s/ssl/private", userdir);
 691         gnutls_Addx509Directory (VLC_OBJECT (p_session), p_sys->x509_cred,
 692                                  path, true);
 693         free (userdir);
 694     }
 695
 696     const char *confdir = config_GetConfDir ();
 697     {
 698         char path[strlen (confdir)
 699                    + sizeof ("/ssl/certs/ca-certificates.crt")];
 700         sprintf (path, "%s/ssl/certs/ca-certificates.crt", confdir);
 701         gnutls_Addx509File (VLC_OBJECT (p_session),
 702                             p_sys->x509_cred, path, false);
 703     }
 704     p_session->pf_handshake = gnutls_HandshakeAndValidate;
 705     /*p_session->pf_handshake = gnutls_ContinueHandshake;*/
 706
 707     i_val = gnutls_init (&p_sys->session.session, GNUTLS_CLIENT);
 708     if (i_val != 0)
 709     {
 710         msg_Err (obj, "cannot initialize TLS session: %s",
 711                  gnutls_strerror (i_val));
 712         gnutls_certificate_free_credentials (p_sys->x509_cred);
 713         goto error;
 714     }
 715
 716     if (gnutls_SessionPrioritize (VLC_OBJECT (p_session),
 717                                   p_sys->session.session))
 718         goto s_error;
 719
 720     /* minimum DH prime bits */
 721     gnutls_dh_set_prime_bits (p_sys->session.session, 1024);
 722
 723     i_val = gnutls_credentials_set (p_sys->session.session,
 724                                     GNUTLS_CRD_CERTIFICATE,
 725                                     p_sys->x509_cred);
 726     if (i_val < 0)
 727     {
 728         msg_Err (obj, "cannot set TLS session credentials: %s",
 729                  gnutls_strerror (i_val));
 730         goto s_error;
 731     }
 732
 733     char *servername = var_GetNonEmptyString (p_session, "tls-server-name");
 734     if (servername == NULL )
 735         msg_Err (p_session, "server name missing for TLS session");
 736     else
 737         gnutls_server_name_set (p_sys->session.session, GNUTLS_NAME_DNS,
 738                                 servername, strlen (servername));
 739
 740     p_sys->session.psz_hostname = servername;
 741
 742     return VLC_SUCCESS;
 743
 744 s_error:
 745     gnutls_deinit (p_sys->session.session);
 746     gnutls_certificate_free_credentials (p_sys->x509_cred);
 747 error:
 748     gnutls_Deinit (obj);
 749     free (p_sys);
 750     return VLC_EGENERIC;
 751 }
 752
 753
 754 static void CloseClient (vlc_object_t *obj)
 755 {
 756     tls_session_t *client = (tls_session_t *)obj;
 757     tls_client_sys_t *p_sys = (tls_client_sys_t *)(client->p_sys);
 758
 759     if (p_sys->session.b_handshaked == true)
 760         gnutls_bye (p_sys->session.session, GNUTLS_SHUT_WR);
 761     gnutls_deinit (p_sys->session.session);
 762     /* credentials must be free'd *after* gnutls_deinit() */
 763     gnutls_certificate_free_credentials (p_sys->x509_cred);
 764
 765     gnutls_Deinit (obj);
 766     free (p_sys->session.psz_hostname);
 767     free (p_sys);
 768 }
 769
 770
 771 /**
 772  * Server-side TLS
 773  */
 774 struct tls_server_sys_t
 775 {
 776     gnutls_certificate_credentials_t x509_cred;
 777     gnutls_dh_params_t               dh_params;
 778
 779     struct saved_session_t          *p_cache;
 780     struct saved_session_t          *p_store;
 781     int                              i_cache_size;
 782     vlc_mutex_t                      cache_lock;
 783
 784     int                            (*pf_handshake) (tls_session_t *);
 785 };
 786
 787
 788 /**
 789  * TLS session resumption callbacks (server-side)
 790  */
 791 #define MAX_SESSION_ID    32
 792 #define MAX_SESSION_DATA  1024
 793
 794 typedef struct saved_session_t
 795 {
 796     char id[MAX_SESSION_ID];
 797     char data[MAX_SESSION_DATA];
 798
 799     unsigned i_idlen;
 800     unsigned i_datalen;
 801 } saved_session_t;
 802
 803
 804 static int cb_store( void *p_server, gnutls_datum key, gnutls_datum data )
 805 {
 806     tls_server_sys_t *p_sys = ((tls_server_t *)p_server)->p_sys;
 807
 808     if( ( p_sys->i_cache_size == 0 )
 809      || ( key.size > MAX_SESSION_ID )
 810      || ( data.size > MAX_SESSION_DATA ) )
 811         return -1;
 812
 813     vlc_mutex_lock( &p_sys->cache_lock );
 814
 815     memcpy( p_sys->p_store->id, key.data, key.size);
 816     memcpy( p_sys->p_store->data, data.data, data.size );
 817     p_sys->p_store->i_idlen = key.size;
 818     p_sys->p_store->i_datalen = data.size;
 819
 820     p_sys->p_store++;
 821     if( ( p_sys->p_store - p_sys->p_cache ) == p_sys->i_cache_size )
 822         p_sys->p_store = p_sys->p_cache;
 823
 824     vlc_mutex_unlock( &p_sys->cache_lock );
 825
 826     return 0;
 827 }
 828
 829
 830 static gnutls_datum cb_fetch( void *p_server, gnutls_datum key )
 831 {
 832     static const gnutls_datum_t err_datum = { NULL, 0 };
 833     tls_server_sys_t *p_sys = ((tls_server_t *)p_server)->p_sys;
 834     saved_session_t *p_session, *p_end;
 835
 836     p_session = p_sys->p_cache;
 837     p_end = p_session + p_sys->i_cache_size;
 838
 839     vlc_mutex_lock( &p_sys->cache_lock );
 840
 841     while( p_session < p_end )
 842     {
 843         if( ( p_session->i_idlen == key.size )
 844          && !memcmp( p_session->id, key.data, key.size ) )
 845         {
 846             gnutls_datum_t data;
 847
 848             data.size = p_session->i_datalen;
 849
 850             data.data = gnutls_malloc( data.size );
 851             if( data.data == NULL )
 852             {
 853                 vlc_mutex_unlock( &p_sys->cache_lock );
 854                 return err_datum;
 855             }
 856
 857             memcpy( data.data, p_session->data, data.size );
 858             vlc_mutex_unlock( &p_sys->cache_lock );
 859             return data;
 860         }
 861         p_session++;
 862     }
 863
 864     vlc_mutex_unlock( &p_sys->cache_lock );
 865
 866     return err_datum;
 867 }
 868
 869
 870 static int cb_delete( void *p_server, gnutls_datum key )
 871 {
 872     tls_server_sys_t *p_sys = ((tls_server_t *)p_server)->p_sys;
 873     saved_session_t *p_session, *p_end;
 874
 875     p_session = p_sys->p_cache;
 876     p_end = p_session + p_sys->i_cache_size;
 877
 878     vlc_mutex_lock( &p_sys->cache_lock );
 879
 880     while( p_session < p_end )
 881     {
 882         if( ( p_session->i_idlen == key.size )
 883          && !memcmp( p_session->id, key.data, key.size ) )
 884         {
 885             p_session->i_datalen = p_session->i_idlen = 0;
 886             vlc_mutex_unlock( &p_sys->cache_lock );
 887             return 0;
 888         }
 889         p_session++;
 890     }
 891
 892     vlc_mutex_unlock( &p_sys->cache_lock );
 893
 894     return -1;
 895 }
 896
 897
 898 /**
 899  * Terminates TLS session and releases session data.
 900  * You still have to close the socket yourself.
 901  */
 902 static void
 903 gnutls_SessionClose (tls_server_t *p_server, tls_session_t *p_session)
 904 {
 905     tls_session_sys_t *p_sys = p_session->p_sys;
 906     (void)p_server;
 907
 908     if( p_sys->b_handshaked == true )
 909         gnutls_bye( p_sys->session, GNUTLS_SHUT_WR );
 910     gnutls_deinit( p_sys->session );
 911
 912     vlc_object_release( p_session );
 913
 914     free( p_sys );
 915 }
 916
 917
 918 /**
 919  * Initializes a server-side TLS session.
 920  */
 921 static tls_session_t *
 922 gnutls_ServerSessionPrepare( tls_server_t *p_server )
 923 {
 924     tls_session_t *p_session;
 925     tls_server_sys_t *p_server_sys;
 926     gnutls_session_t session;
 927     int i_val;
 928
 929     p_session = vlc_object_create( p_server, sizeof (struct tls_session_t) );
 930     if( p_session == NULL )
 931         return NULL;
 932
 933     p_session->p_sys = malloc( sizeof(struct tls_session_sys_t) );
 934     if( p_session->p_sys == NULL )
 935     {
 936         vlc_object_release( p_session );
 937         return NULL;
 938     }
 939
 940     p_server_sys = p_server->p_sys;
 941     p_session->sock.p_sys = p_session;
 942     p_session->sock.pf_send = gnutls_Send;
 943     p_session->sock.pf_recv = gnutls_Recv;
 944     p_session->pf_set_fd = gnutls_SetFD;
 945     p_session->pf_handshake = p_server_sys->pf_handshake;
 946
 947     p_session->p_sys->b_handshaked = false;
 948     p_session->p_sys->psz_hostname = NULL;
 949
 950     i_val = gnutls_init( &session, GNUTLS_SERVER );
 951     if( i_val != 0 )
 952     {
 953         msg_Err( p_server, "cannot initialize TLS session: %s",
 954                  gnutls_strerror( i_val ) );
 955         goto error;
 956     }
 957
 958     p_session->p_sys->session = session;
 959
 960     if (gnutls_SessionPrioritize (VLC_OBJECT (p_session), session))
 961     {
 962         gnutls_deinit( session );
 963         goto error;
 964     }
 965
 966     i_val = gnutls_credentials_set( session, GNUTLS_CRD_CERTIFICATE,
 967                                     p_server_sys->x509_cred );
 968     if( i_val < 0 )
 969     {
 970         msg_Err( p_server, "cannot set TLS session credentials: %s",
 971                  gnutls_strerror( i_val ) );
 972         gnutls_deinit( session );
 973         goto error;
 974     }
 975
 976     if (p_session->pf_handshake == gnutls_HandshakeAndValidate)
 977         gnutls_certificate_server_set_request (session, GNUTLS_CERT_REQUIRE);
 978
 979     /* Session resumption support */
 980     i_val = var_InheritInteger (p_server, "gnutls-cache-timeout");
 981     if (i_val >= 0)
 982         gnutls_db_set_cache_expiration (session, i_val);
 983     gnutls_db_set_retrieve_function( session, cb_fetch );
 984     gnutls_db_set_remove_function( session, cb_delete );
 985     gnutls_db_set_store_function( session, cb_store );
 986     gnutls_db_set_ptr( session, p_server );
 987
 988     return p_session;
 989
 990 error:
 991     free( p_session->p_sys );
 992     vlc_object_release( p_session );
 993     return NULL;
 994 }
 995
 996
 997 /**
 998  * Adds one or more certificate authorities.
 999  *
1000  * @param psz_ca_path (Unicode) path to an x509 certificates list.
1001  *
1002  * @return -1 on error, 0 on success.
1003  */
1004 static int
1005 gnutls_ServerAddCA( tls_server_t *p_server, const char *psz_ca_path )
1006 {
1007     tls_server_sys_t *p_sys;
1008     char *psz_local_path;
1009     int val;
1010
1011     p_sys = (tls_server_sys_t *)(p_server->p_sys);
1012
1013     psz_local_path = ToLocale( psz_ca_path );
1014     val = gnutls_certificate_set_x509_trust_file( p_sys->x509_cred,
1015                                                   psz_local_path,
1016                                                   GNUTLS_X509_FMT_PEM );
1017     LocaleFree( psz_local_path );
1018     if( val < 0 )
1019     {
1020         msg_Err( p_server, "cannot add trusted CA (%s): %s", psz_ca_path,
1021                  gnutls_strerror( val ) );
1022         return VLC_EGENERIC;
1023     }
1024     msg_Dbg( p_server, " %d trusted CA added (%s)", val, psz_ca_path );
1025
1026     /* enables peer's certificate verification */
1027     p_sys->pf_handshake = gnutls_HandshakeAndValidate;
1028
1029     return VLC_SUCCESS;
1030 }
1031
1032
1033 /**
1034  * Adds a certificates revocation list to be sent to TLS clients.
1035  *
1036  * @param psz_crl_path (Unicode) path of the CRL file.
1037  *
1038  * @return -1 on error, 0 on success.
1039  */
1040 static int
1041 gnutls_ServerAddCRL( tls_server_t *p_server, const char *psz_crl_path )
1042 {
1043     int val;
1044     char *psz_local_path = ToLocale( psz_crl_path );
1045
1046     val = gnutls_certificate_set_x509_crl_file( ((tls_server_sys_t *)
1047                                                 (p_server->p_sys))->x509_cred,
1048                                                 psz_local_path,
1049                                                 GNUTLS_X509_FMT_PEM );
1050     LocaleFree( psz_crl_path );
1051     if( val < 0 )
1052     {
1053         msg_Err( p_server, "cannot add CRL (%s): %s", psz_crl_path,
1054                  gnutls_strerror( val ) );
1055         return VLC_EGENERIC;
1056     }
1057     msg_Dbg( p_server, "%d CRL added (%s)", val, psz_crl_path );
1058     return VLC_SUCCESS;
1059 }
1060
1061
1062 /**
1063  * Allocates a whole server's TLS credentials.
1064  */
1065 static int OpenServer (vlc_object_t *obj)
1066 {
1067     tls_server_t *p_server = (tls_server_t *)obj;
1068     tls_server_sys_t *p_sys;
1069     int val;
1070
1071     if (gnutls_Init (obj))
1072         return VLC_EGENERIC;
1073
1074     msg_Dbg (obj, "creating TLS server");
1075
1076     p_sys = (tls_server_sys_t *)malloc( sizeof(struct tls_server_sys_t) );
1077     if( p_sys == NULL )
1078         return VLC_ENOMEM;
1079
1080     p_sys->i_cache_size = var_InheritInteger (obj, "gnutls-cache-size");
1081     if (p_sys->i_cache_size == -1) /* Duh, config subsystem exploded?! */
1082         p_sys->i_cache_size = 0;
1083     p_sys->p_cache = calloc (p_sys->i_cache_size,
1084                              sizeof (struct saved_session_t));
1085     if (p_sys->p_cache == NULL)
1086     {
1087         free (p_sys);
1088         return VLC_ENOMEM;
1089     }
1090
1091     p_sys->p_store = p_sys->p_cache;
1092     p_server->p_sys = p_sys;
1093     p_server->pf_add_CA  = gnutls_ServerAddCA;
1094     p_server->pf_add_CRL = gnutls_ServerAddCRL;
1095     p_server->pf_open    = gnutls_ServerSessionPrepare;
1096     p_server->pf_close   = gnutls_SessionClose;
1097
1098     /* No certificate validation by default */
1099     p_sys->pf_handshake  = gnutls_ContinueHandshake;
1100
1101     vlc_mutex_init( &p_sys->cache_lock );
1102
1103     /* Sets server's credentials */
1104     val = gnutls_certificate_allocate_credentials( &p_sys->x509_cred );
1105     if( val != 0 )
1106     {
1107         msg_Err( p_server, "cannot allocate X509 credentials: %s",
1108                  gnutls_strerror( val ) );
1109         goto error;
1110     }
1111
1112     char *psz_cert_path = var_GetNonEmptyString (obj, "tls-x509-cert");
1113     char *psz_key_path = var_GetNonEmptyString (obj, "tls-x509-key");
1114     const char *psz_local_cert = ToLocale (psz_cert_path);
1115     const char *psz_local_key = ToLocale (psz_key_path);
1116     val = gnutls_certificate_set_x509_key_file (p_sys->x509_cred,
1117                                                 psz_local_cert, psz_local_key,
1118                                                 GNUTLS_X509_FMT_PEM );
1119     LocaleFree (psz_local_key);
1120     free (psz_key_path);
1121     LocaleFree (psz_local_cert);
1122     free (psz_cert_path);
1123
1124     if( val < 0 )
1125     {
1126         msg_Err( p_server, "cannot set certificate chain or private key: %s",
1127                  gnutls_strerror( val ) );
1128         gnutls_certificate_free_credentials( p_sys->x509_cred );
1129         goto error;
1130     }
1131
1132     /* FIXME:
1133      * - support other ciper suites
1134      */
1135     val = gnutls_dh_params_init (&p_sys->dh_params);
1136     if (val >= 0)
1137     {
1138         const gnutls_datum_t data = {
1139             .data = (unsigned char *)dh_params,
1140             .size = sizeof (dh_params) - 1,
1141         };
1142
1143         val = gnutls_dh_params_import_pkcs3 (p_sys->dh_params, &data,
1144                                              GNUTLS_X509_FMT_PEM);
1145         if (val == 0)
1146             gnutls_certificate_set_dh_params (p_sys->x509_cred,
1147                                               p_sys->dh_params);
1148     }
1149     if (val < 0)
1150     {
1151         msg_Err (p_server, "cannot initialize DHE cipher suites: %s",
1152                  gnutls_strerror (val));
1153     }
1154
1155     return VLC_SUCCESS;
1156
1157 error:
1158     vlc_mutex_destroy (&p_sys->cache_lock);
1159     free (p_sys->p_cache);
1160     free (p_sys);
1161     return VLC_EGENERIC;
1162 }
1163
1164 /**
1165  * Destroys a TLS server object.
1166  */
1167 static void CloseServer (vlc_object_t *p_server)
1168 {
1169     tls_server_sys_t *p_sys = ((tls_server_t *)p_server)->p_sys;
1170
1171     vlc_mutex_destroy (&p_sys->cache_lock);
1172     free (p_sys->p_cache);
1173
1174     /* all sessions depending on the server are now deinitialized */
1175     gnutls_certificate_free_credentials (p_sys->x509_cred);
1176     gnutls_dh_params_deinit (p_sys->dh_params);
1177     free (p_sys);
1178
1179     gnutls_Deinit (p_server);
1180 }