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 PRIORITIES_TEXT N_("TLS cipher priorities")
  77 #define PRIORITIES_LONGTEXT N_("Ciphers, key exchange methods, " \
  78     "hash functions and compression methods can be selected. " \
  79     "Refer to GNU TLS documentation for detailed syntax.")
  80 static const char *const priorities_values[] = {
  81     "PERFORMANCE",
  82     "NORMAL",
  83     "SECURE128",
  84     "SECURE256",
  85     "EXPORT",
  86 };
  87 static const char *const priorities_text[] = {
  88     N_("Performance (prioritize faster ciphers)"),
  89     N_("Normal"),
  90     N_("Secure 128-bits (exclude 256-bits ciphers)"),
  91     N_("Secure 256-bits (prioritize 256-bits ciphers)"),
  92     N_("Export (include insecure ciphers)"),
  93 };
  94
  95 #define CACHE_TIMEOUT_TEXT N_("Expiration time for resumed TLS sessions")
  96 #define CACHE_TIMEOUT_LONGTEXT N_( \
  97     "It is possible to cache the resumed TLS sessions. This is the expiration "\
  98     "time of the sessions stored in this cache, in seconds." )
  99
 100 #define CACHE_SIZE_TEXT N_("Number of resumed TLS sessions")
 101 #define CACHE_SIZE_LONGTEXT N_( \
 102     "This is the maximum number of resumed TLS sessions that " \
 103     "the cache will hold." )
 104
 105 vlc_module_begin ()
 106     set_shortname( "GNU TLS" )
 107     set_description( N_("GNU TLS transport layer security") )
 108     set_capability( "tls client", 1 )
 109     set_callbacks( OpenClient, CloseClient )
 110     set_category( CAT_ADVANCED )
 111     set_subcategory( SUBCAT_ADVANCED_MISC )
 112
 113     add_submodule ()
 114         set_description( N_("GNU TLS server") )
 115         set_capability( "tls server", 1 )
 116         set_category( CAT_ADVANCED )
 117         set_subcategory( SUBCAT_ADVANCED_MISC )
 118         set_callbacks( OpenServer, CloseServer )
 119
 120         add_string ("gnutls-priorities", "NORMAL", PRIORITIES_TEXT,
 121                     PRIORITIES_LONGTEXT, false)
 122             change_string_list (priorities_values, priorities_text, NULL)
 123         add_integer( "gnutls-cache-timeout", CACHE_TIMEOUT,
 124                     CACHE_TIMEOUT_TEXT, CACHE_TIMEOUT_LONGTEXT, true )
 125         add_integer( "gnutls-cache-size", CACHE_SIZE, CACHE_SIZE_TEXT,
 126                     CACHE_SIZE_LONGTEXT, true )
 127 vlc_module_end ()
 128
 129 static vlc_mutex_t gnutls_mutex = VLC_STATIC_MUTEX;
 130
 131 /**
 132  * Initializes GnuTLS with proper locking.
 133  * @return VLC_SUCCESS on success, a VLC error code otherwise.
 134  */
 135 static int gnutls_Init (vlc_object_t *p_this)
 136 {
 137     int ret = VLC_EGENERIC;
 138
 139     vlc_gcrypt_init (); /* GnuTLS depends on gcrypt */
 140
 141     vlc_mutex_lock (&gnutls_mutex);
 142     if (gnutls_global_init ())
 143     {
 144         msg_Err (p_this, "cannot initialize GnuTLS");
 145         goto error;
 146     }
 147
 148     const char *psz_version = gnutls_check_version ("1.3.3");
 149     if (psz_version == NULL)
 150     {
 151         msg_Err (p_this, "unsupported GnuTLS version");
 152         gnutls_global_deinit ();
 153         goto error;
 154     }
 155
 156     msg_Dbg (p_this, "GnuTLS v%s initialized", psz_version);
 157     ret = VLC_SUCCESS;
 158
 159 error:
 160     vlc_mutex_unlock (&gnutls_mutex);
 161     return ret;
 162 }
 163
 164
 165 /**
 166  * Deinitializes GnuTLS.
 167  */
 168 static void gnutls_Deinit (vlc_object_t *p_this)
 169 {
 170     vlc_mutex_lock (&gnutls_mutex);
 171
 172     gnutls_global_deinit ();
 173     msg_Dbg (p_this, "GnuTLS deinitialized");
 174     vlc_mutex_unlock (&gnutls_mutex);
 175 }
 176
 177
 178 static int gnutls_Error (vlc_object_t *obj, int val)
 179 {
 180     switch (val)
 181     {
 182         case GNUTLS_E_AGAIN:
 183 #ifdef WIN32
 184             WSASetLastError (WSAEWOULDBLOCK);
 185 #else
 186             errno = EAGAIN;
 187 #endif
 188             break;
 189
 190         case GNUTLS_E_INTERRUPTED:
 191 #ifdef WIN32
 192             WSASetLastError (WSAEINTR);
 193 #else
 194             errno = EINTR;
 195 #endif
 196             break;
 197
 198         default:
 199             msg_Err (obj, "%s", gnutls_strerror (val));
 200 #ifndef NDEBUG
 201             if (!gnutls_error_is_fatal (val))
 202                 msg_Err (obj, "Error above should be handled");
 203 #endif
 204 #ifdef WIN32
 205             WSASetLastError (WSAECONNRESET);
 206 #else
 207             errno = ECONNRESET;
 208 #endif
 209     }
 210     return -1;
 211 }
 212
 213
 214 struct tls_session_sys_t
 215 {
 216     gnutls_session_t session;
 217     char            *psz_hostname;
 218     bool       b_handshaked;
 219 };
 220
 221
 222 /**
 223  * Sends data through a TLS session.
 224  */
 225 static int
 226 gnutls_Send( void *p_session, const void *buf, int i_length )
 227 {
 228     int val;
 229     tls_session_sys_t *p_sys;
 230
 231     p_sys = (tls_session_sys_t *)(((tls_session_t *)p_session)->p_sys);
 232
 233     val = gnutls_record_send( p_sys->session, buf, i_length );
 234     return (val < 0) ? gnutls_Error ((vlc_object_t *)p_session, val) : val;
 235 }
 236
 237
 238 /**
 239  * Receives data through a TLS session.
 240  */
 241 static int
 242 gnutls_Recv( void *p_session, void *buf, int i_length )
 243 {
 244     int val;
 245     tls_session_sys_t *p_sys;
 246
 247     p_sys = (tls_session_sys_t *)(((tls_session_t *)p_session)->p_sys);
 248
 249     val = gnutls_record_recv( p_sys->session, buf, i_length );
 250     return (val < 0) ? gnutls_Error ((vlc_object_t *)p_session, val) : val;
 251 }
 252
 253
 254 /**
 255  * Starts or continues the TLS handshake.
 256  *
 257  * @return -1 on fatal error, 0 on successful handshake completion,
 258  * 1 if more would-be blocking recv is needed,
 259  * 2 if more would-be blocking send is required.
 260  */
 261 static int
 262 gnutls_ContinueHandshake (tls_session_t *p_session)
 263 {
 264     tls_session_sys_t *p_sys = p_session->p_sys;
 265     int val;
 266
 267 #ifdef WIN32
 268     WSASetLastError( 0 );
 269 #endif
 270     val = gnutls_handshake( p_sys->session );
 271     if( ( val == GNUTLS_E_AGAIN ) || ( val == GNUTLS_E_INTERRUPTED ) )
 272         return 1 + gnutls_record_get_direction( p_sys->session );
 273
 274     if( val < 0 )
 275     {
 276 #ifdef WIN32
 277         msg_Dbg( p_session, "Winsock error %d", WSAGetLastError( ) );
 278 #endif
 279         msg_Err( p_session, "TLS handshake error: %s",
 280                  gnutls_strerror( val ) );
 281         return -1;
 282     }
 283
 284     p_sys->b_handshaked = true;
 285     return 0;
 286 }
 287
 288
 289 typedef struct
 290 {
 291     int flag;
 292     const char *msg;
 293 } error_msg_t;
 294
 295 static const error_msg_t cert_errors[] =
 296 {
 297     { GNUTLS_CERT_INVALID,
 298         "Certificate could not be verified" },
 299     { GNUTLS_CERT_REVOKED,
 300         "Certificate was revoked" },
 301     { GNUTLS_CERT_SIGNER_NOT_FOUND,
 302         "Certificate's signer was not found" },
 303     { GNUTLS_CERT_SIGNER_NOT_CA,
 304         "Certificate's signer is not a CA" },
 305     { GNUTLS_CERT_INSECURE_ALGORITHM,
 306         "Insecure certificate signature algorithm" },
 307     { 0, NULL }
 308 };
 309
 310
 311 static int
 312 gnutls_HandshakeAndValidate( tls_session_t *session )
 313 {
 314     int val = gnutls_ContinueHandshake( session );
 315     if( val )
 316         return val;
 317
 318     tls_session_sys_t *p_sys = (tls_session_sys_t *)(session->p_sys);
 319
 320     /* certificates chain verification */
 321     unsigned status;
 322     val = gnutls_certificate_verify_peers2( p_sys->session, &status );
 323
 324     if( val )
 325     {
 326         msg_Err( session, "Certificate verification failed: %s",
 327                  gnutls_strerror( val ) );
 328         return -1;
 329     }
 330
 331     if( status )
 332     {
 333         msg_Err( session, "TLS session: access denied" );
 334         for( const error_msg_t *e = cert_errors; e->flag; e++ )
 335         {
 336             if( status & e->flag )
 337             {
 338                 msg_Err( session, "%s", e->msg );
 339                 status &= ~e->flag;
 340             }
 341         }
 342
 343         if( status )
 344             msg_Err( session,
 345                      "unknown certificate error (you found a bug in VLC)" );
 346
 347         return -1;
 348     }
 349
 350     /* certificate (host)name verification */
 351     const gnutls_datum_t *data;
 352     data = gnutls_certificate_get_peers (p_sys->session, &(unsigned){0});
 353     if( data == NULL )
 354     {
 355         msg_Err( session, "Peer certificate not available" );
 356         return -1;
 357     }
 358
 359     gnutls_x509_crt_t cert;
 360     val = gnutls_x509_crt_init( &cert );
 361     if( val )
 362     {
 363         msg_Err( session, "x509 fatal error: %s", gnutls_strerror( val ) );
 364         return -1;
 365     }
 366
 367     val = gnutls_x509_crt_import( cert, data, GNUTLS_X509_FMT_DER );
 368     if( val )
 369     {
 370         msg_Err( session, "Certificate import error: %s",
 371                  gnutls_strerror( val ) );
 372         goto error;
 373     }
 374
 375     assert( p_sys->psz_hostname != NULL );
 376     if ( !gnutls_x509_crt_check_hostname( cert, p_sys->psz_hostname ) )
 377     {
 378         msg_Err( session, "Certificate does not match \"%s\"",
 379                  p_sys->psz_hostname );
 380         goto error;
 381     }
 382
 383     if( gnutls_x509_crt_get_expiration_time( cert ) < time( NULL ) )
 384     {
 385         msg_Err( session, "Certificate expired" );
 386         goto error;
 387     }
 388
 389     if( gnutls_x509_crt_get_activation_time( cert ) > time ( NULL ) )
 390     {
 391         msg_Err( session, "Certificate not yet valid" );
 392         goto error;
 393     }
 394
 395     gnutls_x509_crt_deinit( cert );
 396     msg_Dbg( session, "TLS/x509 certificate verified" );
 397     return 0;
 398
 399 error:
 400     gnutls_x509_crt_deinit( cert );
 401     return -1;
 402 }
 403
 404 /**
 405  * Sets the operating system file descriptor backend for the TLS sesison.
 406  *
 407  * @param fd stream socket already connected with the peer.
 408  */
 409 static void
 410 gnutls_SetFD (tls_session_t *p_session, int fd)
 411 {
 412     gnutls_transport_set_ptr (p_session->p_sys->session,
 413                               (gnutls_transport_ptr_t)(intptr_t)fd);
 414 }
 415
 416 static int
 417 gnutls_SessionPrioritize (vlc_object_t *obj, gnutls_session_t session)
 418 {
 419     char *priorities = var_InheritString (obj, "gnutls-priorities");
 420     if (unlikely(priorities == NULL))
 421         return VLC_ENOMEM;
 422
 423     const char *errp;
 424     int val = gnutls_priority_set_direct (session, priorities, &errp);
 425     if (val < 0)
 426     {
 427         msg_Err (obj, "cannot set TLS priorities \"%s\": %s", errp,
 428                  gnutls_strerror (val));
 429         val = VLC_EGENERIC;
 430     }
 431     else
 432         val = VLC_SUCCESS;
 433     free (priorities);
 434     return val;
 435 }
 436
 437
 438 static int
 439 gnutls_Addx509File( vlc_object_t *p_this,
 440                     gnutls_certificate_credentials_t cred,
 441                     const char *psz_path, bool b_priv );
 442
 443 static int
 444 gnutls_Addx509Directory( vlc_object_t *p_this,
 445                          gnutls_certificate_credentials_t cred,
 446                          const char *psz_dirname,
 447                          bool b_priv )
 448 {
 449     DIR* dir;
 450
 451     if( *psz_dirname == '\0' )
 452         psz_dirname = ".";
 453
 454     dir = vlc_opendir( psz_dirname );
 455     if( dir == NULL )
 456     {
 457         if (errno != ENOENT)
 458         {
 459             msg_Err (p_this, "cannot open directory (%s): %m", psz_dirname);
 460             return VLC_EGENERIC;
 461         }
 462
 463         msg_Dbg (p_this, "creating empty certificate directory: %s",
 464                  psz_dirname);
 465         vlc_mkdir (psz_dirname, b_priv ? 0700 : 0755);
 466         return VLC_SUCCESS;
 467     }
 468 #ifdef S_ISLNK
 469     else
 470     {
 471         struct stat st1, st2;
 472         int fd = dirfd( dir );
 473
 474         /*
 475          * Gets stats for the directory path, checks that it is not a
 476          * symbolic link (to avoid possibly infinite recursion), and verifies
 477          * that the inode is still the same, to avoid TOCTOU race condition.
 478          */
 479         if( ( fd == -1)
 480          || fstat( fd, &st1 ) || vlc_lstat( psz_dirname, &st2 )
 481          || S_ISLNK( st2.st_mode ) || ( st1.st_ino != st2.st_ino ) )
 482         {
 483             closedir( dir );
 484             return VLC_EGENERIC;
 485         }
 486     }
 487 #endif
 488
 489     for (;;)
 490     {
 491         char *ent = vlc_readdir (dir);
 492         if (ent == NULL)
 493             break;
 494
 495         if ((strcmp (ent, ".") == 0) || (strcmp (ent, "..") == 0))
 496         {
 497             free( ent );
 498             continue;
 499         }
 500
 501         char path[strlen (psz_dirname) + strlen (ent) + 2];
 502         sprintf (path, "%s"DIR_SEP"%s", psz_dirname, ent);
 503         free (ent);
 504
 505         gnutls_Addx509File( p_this, cred, path, b_priv );
 506     }
 507
 508     closedir( dir );
 509     return VLC_SUCCESS;
 510 }
 511
 512
 513 static int
 514 gnutls_Addx509File( vlc_object_t *p_this,
 515                     gnutls_certificate_credentials cred,
 516                     const char *psz_path, bool b_priv )
 517 {
 518     struct stat st;
 519
 520     int fd = vlc_open (psz_path, O_RDONLY);
 521     if (fd == -1)
 522         goto error;
 523
 524     block_t *block = block_File (fd);
 525     if (block != NULL)
 526     {
 527         close (fd);
 528
 529         gnutls_datum data = {
 530             .data = block->p_buffer,
 531             .size = block->i_buffer,
 532         };
 533         int res = b_priv
 534             ? gnutls_certificate_set_x509_key_mem (cred, &data, &data,
 535                                                    GNUTLS_X509_FMT_PEM)
 536             : gnutls_certificate_set_x509_trust_mem (cred, &data,
 537                                                      GNUTLS_X509_FMT_PEM);
 538         block_Release (block);
 539
 540         if (res < 0)
 541         {
 542             msg_Warn (p_this, "cannot add x509 credentials (%s): %s",
 543                       psz_path, gnutls_strerror (res));
 544             return VLC_EGENERIC;
 545         }
 546         msg_Dbg (p_this, "added x509 credentials (%s)", psz_path);
 547         return VLC_SUCCESS;
 548     }
 549
 550     if (!fstat (fd, &st) && S_ISDIR (st.st_mode))
 551     {
 552         close (fd);
 553         msg_Dbg (p_this, "looking recursively for x509 credentials in %s",
 554                  psz_path);
 555         return gnutls_Addx509Directory (p_this, cred, psz_path, b_priv);
 556     }
 557
 558 error:
 559     msg_Warn (p_this, "cannot add x509 credentials (%s): %m", psz_path);
 560     if (fd != -1)
 561         close (fd);
 562     return VLC_EGENERIC;
 563 }
 564
 565
 566 /** TLS client session data */
 567 typedef struct tls_client_sys_t
 568 {
 569     struct tls_session_sys_t         session;
 570     gnutls_certificate_credentials_t x509_cred;
 571 } tls_client_sys_t;
 572
 573
 574 /**
 575  * Initializes a client-side TLS session.
 576  */
 577 static int OpenClient (vlc_object_t *obj)
 578 {
 579     tls_session_t *p_session = (tls_session_t *)obj;
 580     int i_val;
 581
 582     if (gnutls_Init (obj))
 583         return VLC_EGENERIC;
 584
 585     tls_client_sys_t *p_sys = malloc (sizeof (*p_sys));
 586     if (p_sys == NULL)
 587     {
 588         gnutls_Deinit (obj);
 589         return VLC_ENOMEM;
 590     }
 591
 592     p_session->p_sys = &p_sys->session;
 593     p_session->sock.p_sys = p_session;
 594     p_session->sock.pf_send = gnutls_Send;
 595     p_session->sock.pf_recv = gnutls_Recv;
 596     p_session->pf_set_fd = gnutls_SetFD;
 597
 598     p_sys->session.b_handshaked = false;
 599
 600     i_val = gnutls_certificate_allocate_credentials (&p_sys->x509_cred);
 601     if (i_val != 0)
 602     {
 603         msg_Err (obj, "cannot allocate X509 credentials: %s",
 604                  gnutls_strerror (i_val));
 605         goto error;
 606     }
 607
 608     char *userdir = config_GetUserDir ( VLC_DATA_DIR );
 609     if (userdir != NULL)
 610     {
 611         char path[strlen (userdir) + sizeof ("/ssl/private")];
 612         sprintf (path, "%s/ssl", userdir);
 613         vlc_mkdir (path, 0755);
 614
 615         sprintf (path, "%s/ssl/certs", userdir);
 616         gnutls_Addx509Directory (VLC_OBJECT (p_session),
 617                                  p_sys->x509_cred, path, false);
 618         sprintf (path, "%s/ssl/private", userdir);
 619         gnutls_Addx509Directory (VLC_OBJECT (p_session), p_sys->x509_cred,
 620                                  path, true);
 621         free (userdir);
 622     }
 623
 624     const char *confdir = config_GetConfDir ();
 625     {
 626         char path[strlen (confdir)
 627                    + sizeof ("/ssl/certs/ca-certificates.crt")];
 628         sprintf (path, "%s/ssl/certs/ca-certificates.crt", confdir);
 629         gnutls_Addx509File (VLC_OBJECT (p_session),
 630                             p_sys->x509_cred, path, false);
 631     }
 632     p_session->pf_handshake = gnutls_HandshakeAndValidate;
 633     /*p_session->pf_handshake = gnutls_ContinueHandshake;*/
 634
 635     i_val = gnutls_init (&p_sys->session.session, GNUTLS_CLIENT);
 636     if (i_val != 0)
 637     {
 638         msg_Err (obj, "cannot initialize TLS session: %s",
 639                  gnutls_strerror (i_val));
 640         gnutls_certificate_free_credentials (p_sys->x509_cred);
 641         goto error;
 642     }
 643
 644     if (gnutls_SessionPrioritize (VLC_OBJECT (p_session),
 645                                   p_sys->session.session))
 646         goto s_error;
 647
 648     /* minimum DH prime bits */
 649     gnutls_dh_set_prime_bits (p_sys->session.session, 1024);
 650
 651     i_val = gnutls_credentials_set (p_sys->session.session,
 652                                     GNUTLS_CRD_CERTIFICATE,
 653                                     p_sys->x509_cred);
 654     if (i_val < 0)
 655     {
 656         msg_Err (obj, "cannot set TLS session credentials: %s",
 657                  gnutls_strerror (i_val));
 658         goto s_error;
 659     }
 660
 661     char *servername = var_GetNonEmptyString (p_session, "tls-server-name");
 662     if (servername == NULL )
 663         msg_Err (p_session, "server name missing for TLS session");
 664     else
 665         gnutls_server_name_set (p_sys->session.session, GNUTLS_NAME_DNS,
 666                                 servername, strlen (servername));
 667
 668     p_sys->session.psz_hostname = servername;
 669
 670     return VLC_SUCCESS;
 671
 672 s_error:
 673     gnutls_deinit (p_sys->session.session);
 674     gnutls_certificate_free_credentials (p_sys->x509_cred);
 675 error:
 676     gnutls_Deinit (obj);
 677     free (p_sys);
 678     return VLC_EGENERIC;
 679 }
 680
 681
 682 static void CloseClient (vlc_object_t *obj)
 683 {
 684     tls_session_t *client = (tls_session_t *)obj;
 685     tls_client_sys_t *p_sys = (tls_client_sys_t *)(client->p_sys);
 686
 687     if (p_sys->session.b_handshaked)
 688         gnutls_bye (p_sys->session.session, GNUTLS_SHUT_WR);
 689     gnutls_deinit (p_sys->session.session);
 690     /* credentials must be free'd *after* gnutls_deinit() */
 691     gnutls_certificate_free_credentials (p_sys->x509_cred);
 692
 693     gnutls_Deinit (obj);
 694     free (p_sys->session.psz_hostname);
 695     free (p_sys);
 696 }
 697
 698
 699 /**
 700  * Server-side TLS
 701  */
 702 struct tls_server_sys_t
 703 {
 704     gnutls_certificate_credentials_t x509_cred;
 705     gnutls_dh_params_t               dh_params;
 706
 707     struct saved_session_t          *p_cache;
 708     struct saved_session_t          *p_store;
 709     int                              i_cache_size;
 710     vlc_mutex_t                      cache_lock;
 711
 712     int                            (*pf_handshake) (tls_session_t *);
 713 };
 714
 715
 716 /**
 717  * TLS session resumption callbacks (server-side)
 718  */
 719 #define MAX_SESSION_ID    32
 720 #define MAX_SESSION_DATA  1024
 721
 722 typedef struct saved_session_t
 723 {
 724     char id[MAX_SESSION_ID];
 725     char data[MAX_SESSION_DATA];
 726
 727     unsigned i_idlen;
 728     unsigned i_datalen;
 729 } saved_session_t;
 730
 731
 732 static int cb_store( void *p_server, gnutls_datum key, gnutls_datum data )
 733 {
 734     tls_server_sys_t *p_sys = ((tls_server_t *)p_server)->p_sys;
 735
 736     if( ( p_sys->i_cache_size == 0 )
 737      || ( key.size > MAX_SESSION_ID )
 738      || ( data.size > MAX_SESSION_DATA ) )
 739         return -1;
 740
 741     vlc_mutex_lock( &p_sys->cache_lock );
 742
 743     memcpy( p_sys->p_store->id, key.data, key.size);
 744     memcpy( p_sys->p_store->data, data.data, data.size );
 745     p_sys->p_store->i_idlen = key.size;
 746     p_sys->p_store->i_datalen = data.size;
 747
 748     p_sys->p_store++;
 749     if( ( p_sys->p_store - p_sys->p_cache ) == p_sys->i_cache_size )
 750         p_sys->p_store = p_sys->p_cache;
 751
 752     vlc_mutex_unlock( &p_sys->cache_lock );
 753
 754     return 0;
 755 }
 756
 757
 758 static gnutls_datum cb_fetch( void *p_server, gnutls_datum key )
 759 {
 760     static const gnutls_datum_t err_datum = { NULL, 0 };
 761     tls_server_sys_t *p_sys = ((tls_server_t *)p_server)->p_sys;
 762     saved_session_t *p_session, *p_end;
 763
 764     p_session = p_sys->p_cache;
 765     p_end = p_session + p_sys->i_cache_size;
 766
 767     vlc_mutex_lock( &p_sys->cache_lock );
 768
 769     while( p_session < p_end )
 770     {
 771         if( ( p_session->i_idlen == key.size )
 772          && !memcmp( p_session->id, key.data, key.size ) )
 773         {
 774             gnutls_datum_t data;
 775
 776             data.size = p_session->i_datalen;
 777
 778             data.data = gnutls_malloc( data.size );
 779             if( data.data == NULL )
 780             {
 781                 vlc_mutex_unlock( &p_sys->cache_lock );
 782                 return err_datum;
 783             }
 784
 785             memcpy( data.data, p_session->data, data.size );
 786             vlc_mutex_unlock( &p_sys->cache_lock );
 787             return data;
 788         }
 789         p_session++;
 790     }
 791
 792     vlc_mutex_unlock( &p_sys->cache_lock );
 793
 794     return err_datum;
 795 }
 796
 797
 798 static int cb_delete( void *p_server, gnutls_datum key )
 799 {
 800     tls_server_sys_t *p_sys = ((tls_server_t *)p_server)->p_sys;
 801     saved_session_t *p_session, *p_end;
 802
 803     p_session = p_sys->p_cache;
 804     p_end = p_session + p_sys->i_cache_size;
 805
 806     vlc_mutex_lock( &p_sys->cache_lock );
 807
 808     while( p_session < p_end )
 809     {
 810         if( ( p_session->i_idlen == key.size )
 811          && !memcmp( p_session->id, key.data, key.size ) )
 812         {
 813             p_session->i_datalen = p_session->i_idlen = 0;
 814             vlc_mutex_unlock( &p_sys->cache_lock );
 815             return 0;
 816         }
 817         p_session++;
 818     }
 819
 820     vlc_mutex_unlock( &p_sys->cache_lock );
 821
 822     return -1;
 823 }
 824
 825
 826 /**
 827  * Terminates TLS session and releases session data.
 828  * You still have to close the socket yourself.
 829  */
 830 static void
 831 gnutls_SessionClose (tls_server_t *p_server, tls_session_t *p_session)
 832 {
 833     tls_session_sys_t *p_sys = p_session->p_sys;
 834     (void)p_server;
 835
 836     if( p_sys->b_handshaked )
 837         gnutls_bye( p_sys->session, GNUTLS_SHUT_WR );
 838     gnutls_deinit( p_sys->session );
 839
 840     vlc_object_release( p_session );
 841
 842     free( p_sys );
 843 }
 844
 845
 846 /**
 847  * Initializes a server-side TLS session.
 848  */
 849 static tls_session_t *
 850 gnutls_ServerSessionPrepare( tls_server_t *p_server )
 851 {
 852     tls_session_t *p_session;
 853     tls_server_sys_t *p_server_sys;
 854     gnutls_session_t session;
 855     int i_val;
 856
 857     p_session = vlc_object_create( p_server, sizeof (struct tls_session_t) );
 858     if( p_session == NULL )
 859         return NULL;
 860
 861     p_session->p_sys = malloc( sizeof(struct tls_session_sys_t) );
 862     if( p_session->p_sys == NULL )
 863     {
 864         vlc_object_release( p_session );
 865         return NULL;
 866     }
 867
 868     p_server_sys = p_server->p_sys;
 869     p_session->sock.p_sys = p_session;
 870     p_session->sock.pf_send = gnutls_Send;
 871     p_session->sock.pf_recv = gnutls_Recv;
 872     p_session->pf_set_fd = gnutls_SetFD;
 873     p_session->pf_handshake = p_server_sys->pf_handshake;
 874
 875     p_session->p_sys->b_handshaked = false;
 876     p_session->p_sys->psz_hostname = NULL;
 877
 878     i_val = gnutls_init( &session, GNUTLS_SERVER );
 879     if( i_val != 0 )
 880     {
 881         msg_Err( p_server, "cannot initialize TLS session: %s",
 882                  gnutls_strerror( i_val ) );
 883         goto error;
 884     }
 885
 886     p_session->p_sys->session = session;
 887
 888     if (gnutls_SessionPrioritize (VLC_OBJECT (p_session), session))
 889     {
 890         gnutls_deinit( session );
 891         goto error;
 892     }
 893
 894     i_val = gnutls_credentials_set( session, GNUTLS_CRD_CERTIFICATE,
 895                                     p_server_sys->x509_cred );
 896     if( i_val < 0 )
 897     {
 898         msg_Err( p_server, "cannot set TLS session credentials: %s",
 899                  gnutls_strerror( i_val ) );
 900         gnutls_deinit( session );
 901         goto error;
 902     }
 903
 904     if (p_session->pf_handshake == gnutls_HandshakeAndValidate)
 905         gnutls_certificate_server_set_request (session, GNUTLS_CERT_REQUIRE);
 906
 907     /* Session resumption support */
 908     i_val = var_InheritInteger (p_server, "gnutls-cache-timeout");
 909     if (i_val >= 0)
 910         gnutls_db_set_cache_expiration (session, i_val);
 911     gnutls_db_set_retrieve_function( session, cb_fetch );
 912     gnutls_db_set_remove_function( session, cb_delete );
 913     gnutls_db_set_store_function( session, cb_store );
 914     gnutls_db_set_ptr( session, p_server );
 915
 916     return p_session;
 917
 918 error:
 919     free( p_session->p_sys );
 920     vlc_object_release( p_session );
 921     return NULL;
 922 }
 923
 924
 925 /**
 926  * Adds one or more certificate authorities.
 927  *
 928  * @param psz_ca_path (Unicode) path to an x509 certificates list.
 929  *
 930  * @return -1 on error, 0 on success.
 931  */
 932 static int
 933 gnutls_ServerAddCA( tls_server_t *p_server, const char *psz_ca_path )
 934 {
 935     tls_server_sys_t *p_sys;
 936     char *psz_local_path;
 937     int val;
 938
 939     p_sys = (tls_server_sys_t *)(p_server->p_sys);
 940
 941     psz_local_path = ToLocale( psz_ca_path );
 942     val = gnutls_certificate_set_x509_trust_file( p_sys->x509_cred,
 943                                                   psz_local_path,
 944                                                   GNUTLS_X509_FMT_PEM );
 945     LocaleFree( psz_local_path );
 946     if( val < 0 )
 947     {
 948         msg_Err( p_server, "cannot add trusted CA (%s): %s", psz_ca_path,
 949                  gnutls_strerror( val ) );
 950         return VLC_EGENERIC;
 951     }
 952     msg_Dbg( p_server, " %d trusted CA added (%s)", val, psz_ca_path );
 953
 954     /* enables peer's certificate verification */
 955     p_sys->pf_handshake = gnutls_HandshakeAndValidate;
 956
 957     return VLC_SUCCESS;
 958 }
 959
 960
 961 /**
 962  * Adds a certificates revocation list to be sent to TLS clients.
 963  *
 964  * @param psz_crl_path (Unicode) path of the CRL file.
 965  *
 966  * @return -1 on error, 0 on success.
 967  */
 968 static int
 969 gnutls_ServerAddCRL( tls_server_t *p_server, const char *psz_crl_path )
 970 {
 971     int val;
 972     char *psz_local_path = ToLocale( psz_crl_path );
 973
 974     val = gnutls_certificate_set_x509_crl_file( ((tls_server_sys_t *)
 975                                                 (p_server->p_sys))->x509_cred,
 976                                                 psz_local_path,
 977                                                 GNUTLS_X509_FMT_PEM );
 978     LocaleFree( psz_crl_path );
 979     if( val < 0 )
 980     {
 981         msg_Err( p_server, "cannot add CRL (%s): %s", psz_crl_path,
 982                  gnutls_strerror( val ) );
 983         return VLC_EGENERIC;
 984     }
 985     msg_Dbg( p_server, "%d CRL added (%s)", val, psz_crl_path );
 986     return VLC_SUCCESS;
 987 }
 988
 989
 990 /**
 991  * Allocates a whole server's TLS credentials.
 992  */
 993 static int OpenServer (vlc_object_t *obj)
 994 {
 995     tls_server_t *p_server = (tls_server_t *)obj;
 996     tls_server_sys_t *p_sys;
 997     int val;
 998
 999     if (gnutls_Init (obj))
1000         return VLC_EGENERIC;
1001
1002     msg_Dbg (obj, "creating TLS server");
1003
1004     p_sys = (tls_server_sys_t *)malloc( sizeof(struct tls_server_sys_t) );
1005     if( p_sys == NULL )
1006         return VLC_ENOMEM;
1007
1008     p_sys->i_cache_size = var_InheritInteger (obj, "gnutls-cache-size");
1009     if (p_sys->i_cache_size == -1) /* Duh, config subsystem exploded?! */
1010         p_sys->i_cache_size = 0;
1011     p_sys->p_cache = calloc (p_sys->i_cache_size,
1012                              sizeof (struct saved_session_t));
1013     if (p_sys->p_cache == NULL)
1014     {
1015         free (p_sys);
1016         return VLC_ENOMEM;
1017     }
1018
1019     p_sys->p_store = p_sys->p_cache;
1020     p_server->p_sys = p_sys;
1021     p_server->pf_add_CA  = gnutls_ServerAddCA;
1022     p_server->pf_add_CRL = gnutls_ServerAddCRL;
1023     p_server->pf_open    = gnutls_ServerSessionPrepare;
1024     p_server->pf_close   = gnutls_SessionClose;
1025
1026     /* No certificate validation by default */
1027     p_sys->pf_handshake  = gnutls_ContinueHandshake;
1028
1029     vlc_mutex_init( &p_sys->cache_lock );
1030
1031     /* Sets server's credentials */
1032     val = gnutls_certificate_allocate_credentials( &p_sys->x509_cred );
1033     if( val != 0 )
1034     {
1035         msg_Err( p_server, "cannot allocate X509 credentials: %s",
1036                  gnutls_strerror( val ) );
1037         goto error;
1038     }
1039
1040     char *psz_cert_path = var_GetNonEmptyString (obj, "tls-x509-cert");
1041     char *psz_key_path = var_GetNonEmptyString (obj, "tls-x509-key");
1042     const char *psz_local_cert = ToLocale (psz_cert_path);
1043     const char *psz_local_key = ToLocale (psz_key_path);
1044     val = gnutls_certificate_set_x509_key_file (p_sys->x509_cred,
1045                                                 psz_local_cert, psz_local_key,
1046                                                 GNUTLS_X509_FMT_PEM );
1047     LocaleFree (psz_local_key);
1048     free (psz_key_path);
1049     LocaleFree (psz_local_cert);
1050     free (psz_cert_path);
1051
1052     if( val < 0 )
1053     {
1054         msg_Err( p_server, "cannot set certificate chain or private key: %s",
1055                  gnutls_strerror( val ) );
1056         gnutls_certificate_free_credentials( p_sys->x509_cred );
1057         goto error;
1058     }
1059
1060     /* FIXME:
1061      * - support other ciper suites
1062      */
1063     val = gnutls_dh_params_init (&p_sys->dh_params);
1064     if (val >= 0)
1065     {
1066         const gnutls_datum_t data = {
1067             .data = (unsigned char *)dh_params,
1068             .size = sizeof (dh_params) - 1,
1069         };
1070
1071         val = gnutls_dh_params_import_pkcs3 (p_sys->dh_params, &data,
1072                                              GNUTLS_X509_FMT_PEM);
1073         if (val == 0)
1074             gnutls_certificate_set_dh_params (p_sys->x509_cred,
1075                                               p_sys->dh_params);
1076     }
1077     if (val < 0)
1078     {
1079         msg_Err (p_server, "cannot initialize DHE cipher suites: %s",
1080                  gnutls_strerror (val));
1081     }
1082
1083     return VLC_SUCCESS;
1084
1085 error:
1086     vlc_mutex_destroy (&p_sys->cache_lock);
1087     free (p_sys->p_cache);
1088     free (p_sys);
1089     return VLC_EGENERIC;
1090 }
1091
1092 /**
1093  * Destroys a TLS server object.
1094  */
1095 static void CloseServer (vlc_object_t *p_server)
1096 {
1097     tls_server_sys_t *p_sys = ((tls_server_t *)p_server)->p_sys;
1098
1099     vlc_mutex_destroy (&p_sys->cache_lock);
1100     free (p_sys->p_cache);
1101
1102     /* all sessions depending on the server are now deinitialized */
1103     gnutls_certificate_free_credentials (p_sys->x509_cred);
1104     gnutls_dh_params_deinit (p_sys->dh_params);
1105     free (p_sys);
1106
1107     gnutls_Deinit (p_server);
1108 }