git.sesse.net Git - vlc/blob - 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 #include <vlc/vlc.h>
  29 #include <stdlib.h>
  30 #include <errno.h>
  31 #include <time.h>
  32
  33 #include <sys/types.h>
  34 #include <errno.h>
  35 #ifdef HAVE_DIRENT_H
  36 # include <dirent.h>
  37 #endif
  38 #ifdef HAVE_SYS_STAT_H
  39 # include <sys/stat.h>
  40 # ifdef HAVE_UNISTD_H
  41 #  include <unistd.h>
  42 # endif
  43 #endif
  44
  45
  46 #include "vlc_tls.h"
  47 #include <vlc_charset.h>
  48
  49 #include <gcrypt.h>
  50 #include <gnutls/gnutls.h>
  51 #include <gnutls/x509.h>
  52
  53 #define DH_BITS             1024
  54 #define CACHE_EXPIRATION    3600
  55 #define CACHE_SIZE          64
  56
  57 /*****************************************************************************
  58  * Module descriptor
  59  *****************************************************************************/
  60 static int  Open ( vlc_object_t * );
  61 static void Close( vlc_object_t * );
  62
  63 #define DH_BITS_TEXT N_("Diffie-Hellman prime bits")
  64 #define DH_BITS_LONGTEXT N_( \
  65     "This allows you to modify the Diffie-Hellman prime's number of bits, " \
  66     "used for TLS or SSL-based server-side encryption. This is generally " \
  67     "not needed." )
  68
  69 #define CACHE_EXPIRATION_TEXT N_("Expiration time for resumed TLS sessions")
  70 #define CACHE_EXPIRATION_LONGTEXT N_( \
  71     "It is possible to cache the resumed TLS sessions. This is the expiration "\
  72     "time of the sessions stored in this cache, in seconds." )
  73
  74 #define CACHE_SIZE_TEXT N_("Number of resumed TLS sessions")
  75 #define CACHE_SIZE_LONGTEXT N_( \
  76     "This is the maximum number of resumed TLS sessions that " \
  77     "the cache will hold." )
  78
  79 #define CHECK_CERT_TEXT N_("Check TLS/SSL server certificate validity")
  80 #define CHECK_CERT_LONGTEXT N_( \
  81     "This ensures that the server certificate is valid " \
  82     "(i.e. signed by an approved Certification Authority)." )
  83
  84 #define CHECK_HOSTNAME_TEXT N_("Check TLS/SSL server hostname in certificate")
  85 #define CHECK_HOSTNAME_LONGTEXT N_( \
  86     "This ensures that the server hostname in certificate matches the " \
  87     "requested host name." )
  88
  89 vlc_module_begin();
  90     set_shortname( "GnuTLS" );
  91     set_description( _("GnuTLS TLS encryption layer") );
  92     set_capability( "tls", 1 );
  93     set_callbacks( Open, Close );
  94     set_category( CAT_ADVANCED );
  95     set_subcategory( SUBCAT_ADVANCED_MISC );
  96
  97     add_bool( "tls-check-cert", VLC_TRUE, NULL, CHECK_CERT_TEXT,
  98               CHECK_CERT_LONGTEXT, VLC_FALSE );
  99     add_bool( "tls-check-hostname", VLC_TRUE, NULL, CHECK_HOSTNAME_TEXT,
 100               CHECK_HOSTNAME_LONGTEXT, VLC_FALSE );
 101
 102     add_integer( "gnutls-dh-bits", DH_BITS, NULL, DH_BITS_TEXT,
 103                  DH_BITS_LONGTEXT, VLC_TRUE );
 104     add_integer( "gnutls-cache-expiration", CACHE_EXPIRATION, NULL,
 105                  CACHE_EXPIRATION_TEXT, CACHE_EXPIRATION_LONGTEXT, VLC_TRUE );
 106     add_integer( "gnutls-cache-size", CACHE_SIZE, NULL, CACHE_SIZE_TEXT,
 107                  CACHE_SIZE_LONGTEXT, VLC_TRUE );
 108 vlc_module_end();
 109
 110
 111 #define MAX_SESSION_ID    32
 112 #define MAX_SESSION_DATA  1024
 113
 114 typedef struct saved_session_t
 115 {
 116     char id[MAX_SESSION_ID];
 117     char data[MAX_SESSION_DATA];
 118
 119     unsigned i_idlen;
 120     unsigned i_datalen;
 121 } saved_session_t;
 122
 123
 124 typedef struct tls_server_sys_t
 125 {
 126     gnutls_certificate_credentials  x509_cred;
 127     gnutls_dh_params                dh_params;
 128
 129     struct saved_session_t          *p_cache;
 130     struct saved_session_t          *p_store;
 131     int                             i_cache_size;
 132     vlc_mutex_t                     cache_lock;
 133
 134     int                             (*pf_handshake2)( tls_session_t * );
 135 } tls_server_sys_t;
 136
 137
 138 typedef struct tls_session_sys_t
 139 {
 140     gnutls_session  session;
 141     char            *psz_hostname;
 142     vlc_bool_t      b_handshaked;
 143 } tls_session_sys_t;
 144
 145
 146 typedef struct tls_client_sys_t
 147 {
 148     struct tls_session_sys_t       session;
 149     gnutls_certificate_credentials x509_cred;
 150 } tls_client_sys_t;
 151
 152
 153 static int gnutls_Error (vlc_object_t *obj, int val)
 154 {
 155     switch (val)
 156     {
 157         case GNUTLS_E_AGAIN:
 158 #if ! defined(WIN32)
 159             errno = EAGAIN;
 160             break;
 161 #endif
 162             /* WinSock does not return EAGAIN, return EINTR instead */
 163
 164         case GNUTLS_E_INTERRUPTED:
 165 #if defined(WIN32)
 166             WSASetLastError(WSAEINTR);
 167 #else
 168             errno = EINTR;
 169 #endif
 170             break;
 171
 172         default:
 173             msg_Err (obj, "%s", gnutls_strerror (val));
 174 #ifdef DEBUG
 175             if (!gnutls_error_is_fatal (val))
 176                 msg_Err (obj, "Error above should be handled");
 177 #endif
 178 #if defined(WIN32)
 179             WSASetLastError(WSAECONNRESET);
 180 #else
 181             errno = ECONNRESET;
 182 #endif
 183     }
 184     return -1;
 185 }
 186
 187
 188 /**
 189  * Sends data through a TLS session.
 190  */
 191 static int
 192 gnutls_Send( void *p_session, const void *buf, int i_length )
 193 {
 194     int val;
 195     tls_session_sys_t *p_sys;
 196
 197     p_sys = (tls_session_sys_t *)(((tls_session_t *)p_session)->p_sys);
 198
 199     val = gnutls_record_send( p_sys->session, buf, i_length );
 200     return (val < 0) ? gnutls_Error ((vlc_object_t *)p_session, val) : val;
 201 }
 202
 203
 204 /**
 205  * Receives data through a TLS session.
 206  */
 207 static int
 208 gnutls_Recv( void *p_session, 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_recv( p_sys->session, buf, i_length );
 216     return (val < 0) ? gnutls_Error ((vlc_object_t *)p_session, val) : val;
 217 }
 218
 219
 220 /*****************************************************************************
 221  * tls_Session(Continue)?Handshake:
 222  *****************************************************************************
 223  * Establishes TLS session with a peer through socket <fd>.
 224  * Returns -1 on error (you need not and must not call tls_SessionClose)
 225  * 0 on succesful handshake completion, 1 if more would-be blocking recv is
 226  * needed, 2 if more would-be blocking send is required.
 227  *****************************************************************************/
 228 static int
 229 gnutls_ContinueHandshake( tls_session_t *p_session)
 230 {
 231     tls_session_sys_t *p_sys;
 232     int val;
 233
 234     p_sys = (tls_session_sys_t *)(p_session->p_sys);
 235
 236 #ifdef WIN32
 237     WSASetLastError( 0 );
 238 #endif
 239     val = gnutls_handshake( p_sys->session );
 240     if( ( val == GNUTLS_E_AGAIN ) || ( val == GNUTLS_E_INTERRUPTED ) )
 241         return 1 + gnutls_record_get_direction( p_sys->session );
 242
 243     if( val < 0 )
 244     {
 245 #ifdef WIN32
 246         msg_Dbg( p_session, "Winsock error %d", WSAGetLastError( ) );
 247 #endif
 248         msg_Err( p_session, "TLS handshake error: %s",
 249                  gnutls_strerror( val ) );
 250         p_session->pf_close( p_session );
 251         return -1;
 252     }
 253
 254     p_sys->b_handshaked = VLC_TRUE;
 255     return 0;
 256 }
 257
 258
 259 typedef struct
 260 {
 261     int flag;
 262     const char *msg;
 263 } error_msg_t;
 264
 265 static const error_msg_t cert_errors[] =
 266 {
 267     { GNUTLS_CERT_INVALID,
 268         "Certificate could not be verified" },
 269     { GNUTLS_CERT_REVOKED,
 270         "Certificate was revoked" },
 271     { GNUTLS_CERT_SIGNER_NOT_FOUND,
 272         "Certificate's signer was not found" },
 273     { GNUTLS_CERT_SIGNER_NOT_CA,
 274         "Certificate's signer is not a CA" },
 275     { GNUTLS_CERT_INSECURE_ALGORITHM,
 276         "Insecure certificate signature algorithm" },
 277     { 0, NULL }
 278 };
 279
 280
 281 static int
 282 gnutls_HandshakeAndValidate( tls_session_t *session )
 283 {
 284     int val = gnutls_ContinueHandshake( session );
 285     if( val )
 286         return val;
 287
 288     tls_session_sys_t *p_sys = (tls_session_sys_t *)(session->p_sys);
 289
 290     /* certificates chain verification */
 291     unsigned status;
 292     val = gnutls_certificate_verify_peers2( p_sys->session, &status );
 293
 294     if( val )
 295     {
 296         msg_Err( session, "Certificate verification failed: %s",
 297                  gnutls_strerror( val ) );
 298         goto error;
 299     }
 300
 301     if( status )
 302     {
 303         msg_Err( session, "TLS session: access denied" );
 304         for( const error_msg_t *e = cert_errors; e->flag; e++ )
 305         {
 306             if( status & e->flag )
 307             {
 308                 msg_Err( session, "%s", e->msg );
 309                 status &= ~e->flag;
 310             }
 311         }
 312
 313         if( status )
 314             msg_Err( session,
 315                      "unknown certificate error (you found a bug in VLC)" );
 316
 317         goto error;
 318     }
 319
 320     /* certificate (host)name verification */
 321     const gnutls_datum *data = gnutls_certificate_get_peers( p_sys->session,
 322                                                              &(size_t){ 0 } );
 323     if( data == NULL )
 324     {
 325         msg_Err( session, "Peer certificate not available" );
 326         goto error;
 327     }
 328
 329     gnutls_x509_crt cert;
 330     val = gnutls_x509_crt_init( &cert );
 331     if( val )
 332     {
 333         msg_Err( session, "x509 fatal error: %s", gnutls_strerror( val ) );
 334         goto error;
 335     }
 336
 337     val = gnutls_x509_crt_import( cert, data, GNUTLS_X509_FMT_DER );
 338     if( val )
 339     {
 340         msg_Err( session, "Certificate import error: %s",
 341                  gnutls_strerror( val ) );
 342         goto crt_error;
 343     }
 344
 345     if( p_sys->psz_hostname != NULL )
 346     {
 347         if ( !gnutls_x509_crt_check_hostname( cert, p_sys->psz_hostname ) )
 348         {
 349             msg_Err( session, "Certificate does not match \"%s\"",
 350                      p_sys->psz_hostname );
 351             goto crt_error;
 352         }
 353     }
 354     else
 355         msg_Warn( session, "Certificate and hostname were not verified" );
 356
 357     if( gnutls_x509_crt_get_expiration_time( cert ) < time( NULL ) )
 358     {
 359         msg_Err( session, "Certificate expired" );
 360         goto crt_error;
 361     }
 362
 363     if( gnutls_x509_crt_get_activation_time( cert ) > time ( NULL ) )
 364     {
 365         msg_Err( session, "Certificate not yet valid" );
 366         goto crt_error;
 367     }
 368
 369     gnutls_x509_crt_deinit( cert );
 370     msg_Dbg( session, "TLS/x509 certificate verified" );
 371     return 0;
 372
 373 crt_error:
 374     gnutls_x509_crt_deinit( cert );
 375 error:
 376     session->pf_close( session );
 377     return -1;
 378 }
 379
 380 /**
 381  * Starts negociation of a TLS session.
 382  *
 383  * @param fd stream socket already connected with the peer.
 384  * @param psz_hostname if not NULL, hostname to mention as a Server Name.
 385  *
 386  * @return -1 on error (you need not and must not call tls_SessionClose),
 387  * 0 on succesful handshake completion, 1 if more would-be blocking recv is
 388  * needed, 2 if more would-be blocking send is required.
 389  */
 390 static int
 391 gnutls_BeginHandshake( tls_session_t *p_session, int fd,
 392                        const char *psz_hostname )
 393 {
 394     tls_session_sys_t *p_sys;
 395
 396     p_sys = (tls_session_sys_t *)(p_session->p_sys);
 397
 398     gnutls_transport_set_ptr (p_sys->session, (gnutls_transport_ptr)(intptr_t)fd);
 399
 400     if( psz_hostname != NULL )
 401     {
 402         gnutls_server_name_set( p_sys->session, GNUTLS_NAME_DNS, psz_hostname,
 403                                 strlen( psz_hostname ) );
 404         if (var_CreateGetBool (p_session, "tls-check-hostname"))
 405         {
 406             p_sys->psz_hostname = strdup( psz_hostname );
 407             if( p_sys->psz_hostname == NULL )
 408             {
 409                 p_session->pf_close( p_session );
 410                 return -1;
 411             }
 412         }
 413     }
 414
 415     return p_session->pf_handshake2( p_session );
 416 }
 417
 418 /**
 419  * Terminates TLS session and releases session data.
 420  * You still have to close the socket yourself.
 421  */
 422 static void
 423 gnutls_SessionClose( tls_session_t *p_session )
 424 {
 425     tls_session_sys_t *p_sys;
 426
 427     p_sys = (tls_session_sys_t *)(p_session->p_sys);
 428
 429     if( p_sys->b_handshaked == VLC_TRUE )
 430         gnutls_bye( p_sys->session, GNUTLS_SHUT_WR );
 431     gnutls_deinit( p_sys->session );
 432
 433     if( p_sys->psz_hostname != NULL )
 434         free( p_sys->psz_hostname );
 435
 436     vlc_object_detach( p_session );
 437     vlc_object_destroy( p_session );
 438
 439     free( p_sys );
 440 }
 441
 442
 443 typedef int (*tls_prio_func) (gnutls_session_t, const int *);
 444
 445 static int
 446 gnutls_SetPriority (vlc_object_t *restrict obj, const char *restrict name,
 447                     tls_prio_func func, gnutls_session_t session,
 448                     const int *restrict values)
 449 {
 450     int val = func (session, values);
 451     if (val < 0)
 452     {
 453         msg_Err (obj, "cannot set %s priorities: %s", name,
 454                  gnutls_strerror (val));
 455         return VLC_EGENERIC;
 456     }
 457     return VLC_SUCCESS;
 458 }
 459
 460
 461 static int
 462 gnutls_SessionPrioritize (vlc_object_t *obj, gnutls_session_t session)
 463 {
 464     /* Note that ordering matters (on the client side) */
 465     static const int protos[] =
 466     {
 467         GNUTLS_TLS1_1,
 468         GNUTLS_TLS1_0,
 469         GNUTLS_SSL3,
 470         0
 471     };
 472     static const int comps[] =
 473     {
 474         GNUTLS_COMP_DEFLATE,
 475         GNUTLS_COMP_NULL,
 476         0
 477     };
 478     static const int macs[] =
 479     {
 480         GNUTLS_MAC_SHA1,
 481         GNUTLS_MAC_RMD160, // RIPEMD
 482         GNUTLS_MAC_MD5,
 483         //GNUTLS_MAC_MD2,
 484         //GNUTLS_MAC_NULL,
 485         0
 486     };
 487     static const int ciphers[] =
 488     {
 489         GNUTLS_CIPHER_AES_256_CBC,
 490         GNUTLS_CIPHER_AES_128_CBC,
 491         GNUTLS_CIPHER_3DES_CBC,
 492         GNUTLS_CIPHER_ARCFOUR_128,
 493         //GNUTLS_CIPHER_DES_CBC,
 494         //GNUTLS_CIPHER_ARCFOUR_40,
 495         //GNUTLS_CIPHER_RC2_40_CBC,
 496         //GNUTLS_CIPHER_NULL,
 497         0
 498     };
 499     static const int kx[] =
 500     {
 501         GNUTLS_KX_DHE_RSA,
 502         GNUTLS_KX_DHE_DSS,
 503         GNUTLS_KX_RSA,
 504         //GNUTLS_KX_RSA_EXPORT,
 505         //GNUTLS_KX_DHE_PSK, TODO
 506         //GNUTLS_KX_PSK,     TODO
 507         //GNUTLS_KX_SRP_RSA, TODO
 508         //GNUTLS_KX_SRP_DSS, TODO
 509         //GNUTLS_KX_SRP,     TODO
 510         //GNUTLS_KX_ANON_DH,
 511         0
 512     };
 513     static const int cert_types[] =
 514     {
 515         GNUTLS_CRT_X509,
 516         //GNUTLS_CRT_OPENPGP, TODO
 517         0
 518     };
 519
 520     int val = gnutls_set_default_priority (session);
 521     if (val < 0)
 522     {
 523         msg_Err (obj, "cannot set default TLS priorities: %s",
 524                  gnutls_strerror (val));
 525         return VLC_EGENERIC;
 526     }
 527
 528     if (gnutls_SetPriority (obj, "protocols",
 529                             gnutls_protocol_set_priority, session, protos)
 530      || gnutls_SetPriority (obj, "compression algorithms",
 531                             gnutls_compression_set_priority, session, comps)
 532      || gnutls_SetPriority (obj, "MAC algorithms",
 533                             gnutls_mac_set_priority, session, macs)
 534      || gnutls_SetPriority (obj, "ciphers",
 535                             gnutls_cipher_set_priority, session, ciphers)
 536      || gnutls_SetPriority (obj, "key exchange algorithms",
 537                             gnutls_kx_set_priority, session, kx)
 538      || gnutls_SetPriority (obj, "certificate types",
 539                             gnutls_certificate_type_set_priority, session,
 540                             cert_types))
 541         return VLC_EGENERIC;
 542
 543     return VLC_SUCCESS;
 544 }
 545
 546
 547 static void
 548 gnutls_ClientDelete( tls_session_t *p_session )
 549 {
 550     /* On the client-side, credentials are re-allocated per session */
 551     gnutls_certificate_credentials x509_cred =
 552                         ((tls_client_sys_t *)(p_session->p_sys))->x509_cred;
 553
 554     gnutls_SessionClose( p_session );
 555
 556     /* credentials must be free'd *after* gnutls_deinit() */
 557     gnutls_certificate_free_credentials( x509_cred );
 558 }
 559
 560
 561 static int
 562 gnutls_Addx509File( vlc_object_t *p_this,
 563                     gnutls_certificate_credentials cred,
 564                     const char *psz_path, vlc_bool_t b_priv );
 565
 566 static int
 567 gnutls_Addx509Directory( vlc_object_t *p_this,
 568                          gnutls_certificate_credentials cred,
 569                          const char *psz_dirname,
 570                          vlc_bool_t b_priv )
 571 {
 572     DIR* dir;
 573
 574     if( *psz_dirname == '\0' )
 575         psz_dirname = ".";
 576
 577     dir = utf8_opendir( psz_dirname );
 578     if( dir == NULL )
 579     {
 580         msg_Warn( p_this, "cannot open directory (%s): %s", psz_dirname,
 581                   strerror( errno ) );
 582         return VLC_EGENERIC;
 583     }
 584 #ifdef S_ISLNK
 585     else
 586     {
 587         struct stat st1, st2;
 588         int fd = dirfd( dir );
 589
 590         /*
 591          * Gets stats for the directory path, checks that it is not a
 592          * symbolic link (to avoid possibly infinite recursion), and verifies
 593          * that the inode is still the same, to avoid TOCTOU race condition.
 594          */
 595         if( ( fd == -1)
 596          || fstat( fd, &st1 ) || utf8_lstat( psz_dirname, &st2 )
 597          || S_ISLNK( st2.st_mode ) || ( st1.st_ino != st2.st_ino ) )
 598         {
 599             closedir( dir );
 600             return VLC_EGENERIC;
 601         }
 602     }
 603 #endif
 604
 605     for (;;)
 606     {
 607         char *ent = utf8_readdir (dir);
 608         if (ent == NULL)
 609             break;
 610
 611         if ((strcmp (ent, ".") == 0) || (strcmp (ent, "..") == 0))
 612             continue;
 613
 614         char path[strlen (psz_dirname) + strlen (ent) + 2];
 615         sprintf (path, "%s"DIR_SEP"%s", psz_dirname, ent);
 616         free (ent);
 617
 618         gnutls_Addx509File( p_this, cred, path, b_priv );
 619     }
 620
 621     closedir( dir );
 622     return VLC_SUCCESS;
 623 }
 624
 625
 626 static int
 627 gnutls_Addx509File( vlc_object_t *p_this,
 628                     gnutls_certificate_credentials cred,
 629                     const char *psz_path, vlc_bool_t b_priv )
 630 {
 631     struct stat st;
 632
 633     if( utf8_stat( psz_path, &st ) == 0 )
 634     {
 635         if( S_ISREG( st.st_mode ) )
 636         {
 637             char *psz_localname = ToLocale( psz_path );
 638             int i = b_priv
 639                     ? gnutls_certificate_set_x509_key_file( cred,
 640                     psz_localname,  psz_localname, GNUTLS_X509_FMT_PEM )
 641                 : gnutls_certificate_set_x509_trust_file( cred,
 642                         psz_localname, GNUTLS_X509_FMT_PEM );
 643             LocaleFree( psz_localname );
 644
 645             if( i < 0 )
 646             {
 647                 msg_Warn( p_this, "cannot add x509 credentials (%s): %s",
 648                           psz_path, gnutls_strerror( i ) );
 649                 return VLC_EGENERIC;
 650             }
 651             else
 652             {
 653                 msg_Dbg( p_this, "added x509 credentials (%s)",
 654                          psz_path );
 655                 return VLC_SUCCESS;
 656             }
 657         }
 658         else if( S_ISDIR( st.st_mode ) )
 659         {
 660             msg_Dbg( p_this,
 661                      "looking recursively for x509 credentials in %s",
 662                      psz_path );
 663             return gnutls_Addx509Directory( p_this, cred, psz_path, b_priv);
 664         }
 665     }
 666     else
 667         msg_Warn( p_this, "cannot add x509 credentials (%s): %s",
 668                   psz_path, strerror( errno ) );
 669     return VLC_EGENERIC;
 670 }
 671
 672
 673 /**
 674  * Initializes a client-side TLS session.
 675  */
 676 static tls_session_t *
 677 gnutls_ClientCreate( tls_t *p_tls )
 678 {
 679     tls_session_t *p_session = NULL;
 680     tls_client_sys_t *p_sys = NULL;
 681     int i_val;
 682
 683     p_sys = (tls_client_sys_t *)malloc( sizeof(struct tls_client_sys_t) );
 684     if( p_sys == NULL )
 685         return NULL;
 686
 687     p_session = (struct tls_session_t *)vlc_object_create ( p_tls, sizeof(struct tls_session_t) );
 688     if( p_session == NULL )
 689     {
 690         free( p_sys );
 691         return NULL;
 692     }
 693
 694     p_session->p_sys = p_sys;
 695     p_session->sock.p_sys = p_session;
 696     p_session->sock.pf_send = gnutls_Send;
 697     p_session->sock.pf_recv = gnutls_Recv;
 698     p_session->pf_handshake = gnutls_BeginHandshake;
 699     p_session->pf_close = gnutls_ClientDelete;
 700
 701     p_sys->session.b_handshaked = VLC_FALSE;
 702     p_sys->session.psz_hostname = NULL;
 703
 704     vlc_object_attach( p_session, p_tls );
 705
 706     const char *homedir = p_tls->p_libvlc->psz_homedir,
 707                *datadir = config_GetDataDir ();
 708     size_t l1 = strlen (homedir), l2 = strlen (datadir);
 709     char path[((l1 > l2) ? l1 : l2) + sizeof ("/"CONFIG_DIR"/ssl/private")];
 710     //                              > sizeof ("/"CONFIG_DIR"/ssl/certs")
 711     //                              > sizeof ("/ca-certificates.crt")
 712
 713     i_val = gnutls_certificate_allocate_credentials( &p_sys->x509_cred );
 714     if( i_val != 0 )
 715     {
 716         msg_Err( p_tls, "cannot allocate X509 credentials: %s",
 717                  gnutls_strerror( i_val ) );
 718         goto error;
 719     }
 720
 721     if (var_CreateGetBool (p_tls, "tls-check-cert"))
 722     {
 723         sprintf (path, "%s/"CONFIG_DIR"/ssl/certs", homedir);
 724         gnutls_Addx509Directory ((vlc_object_t *)p_session,
 725                                   p_sys->x509_cred, path, VLC_FALSE);
 726
 727         sprintf (path, "%s/ca-certificates.crt", datadir);
 728         gnutls_Addx509File ((vlc_object_t *)p_session,
 729                             p_sys->x509_cred, path, VLC_FALSE);
 730         p_session->pf_handshake2 = gnutls_HandshakeAndValidate;
 731     }
 732     else
 733         p_session->pf_handshake2 = gnutls_ContinueHandshake;
 734
 735     sprintf (path, "%s/"CONFIG_DIR"/ssl/private", homedir);
 736     gnutls_Addx509Directory ((vlc_object_t *)p_session, p_sys->x509_cred,
 737                              path, VLC_TRUE);
 738
 739     i_val = gnutls_init( &p_sys->session.session, GNUTLS_CLIENT );
 740     if( i_val != 0 )
 741     {
 742         msg_Err( p_tls, "cannot initialize TLS session: %s",
 743                  gnutls_strerror( i_val ) );
 744         gnutls_certificate_free_credentials( p_sys->x509_cred );
 745         goto error;
 746     }
 747
 748     if (gnutls_SessionPrioritize (VLC_OBJECT (p_session),
 749                                   p_sys->session.session))
 750         goto s_error;
 751
 752     i_val = gnutls_credentials_set( p_sys->session.session,
 753                                     GNUTLS_CRD_CERTIFICATE,
 754                                     p_sys->x509_cred );
 755     if( i_val < 0 )
 756     {
 757         msg_Err( p_tls, "cannot set TLS session credentials: %s",
 758                  gnutls_strerror( i_val ) );
 759         goto s_error;
 760     }
 761
 762     return p_session;
 763
 764 s_error:
 765     gnutls_deinit( p_sys->session.session );
 766     gnutls_certificate_free_credentials( p_sys->x509_cred );
 767
 768 error:
 769     vlc_object_detach( p_session );
 770     vlc_object_destroy( p_session );
 771     free( p_sys );
 772
 773     return NULL;
 774 }
 775
 776
 777 /**
 778  * TLS session resumption callbacks (server-side)
 779  */
 780 static int cb_store( void *p_server, gnutls_datum key, gnutls_datum data )
 781 {
 782     tls_server_sys_t *p_sys = ((tls_server_t *)p_server)->p_sys;
 783
 784     if( ( p_sys->i_cache_size == 0 )
 785      || ( key.size > MAX_SESSION_ID )
 786      || ( data.size > MAX_SESSION_DATA ) )
 787         return -1;
 788
 789     vlc_mutex_lock( &p_sys->cache_lock );
 790
 791     memcpy( p_sys->p_store->id, key.data, key.size);
 792     memcpy( p_sys->p_store->data, data.data, data.size );
 793     p_sys->p_store->i_idlen = key.size;
 794     p_sys->p_store->i_datalen = data.size;
 795
 796     p_sys->p_store++;
 797     if( ( p_sys->p_store - p_sys->p_cache ) == p_sys->i_cache_size )
 798         p_sys->p_store = p_sys->p_cache;
 799
 800     vlc_mutex_unlock( &p_sys->cache_lock );
 801
 802     return 0;
 803 }
 804
 805
 806 static const gnutls_datum err_datum = { NULL, 0 };
 807
 808 static gnutls_datum cb_fetch( void *p_server, gnutls_datum key )
 809 {
 810     tls_server_sys_t *p_sys = ((tls_server_t *)p_server)->p_sys;
 811     saved_session_t *p_session, *p_end;
 812
 813     p_session = p_sys->p_cache;
 814     p_end = p_session + p_sys->i_cache_size;
 815
 816     vlc_mutex_lock( &p_sys->cache_lock );
 817
 818     while( p_session < p_end )
 819     {
 820         if( ( p_session->i_idlen == key.size )
 821          && !memcmp( p_session->id, key.data, key.size ) )
 822         {
 823             gnutls_datum data;
 824
 825             data.size = p_session->i_datalen;
 826
 827             data.data = gnutls_malloc( data.size );
 828             if( data.data == NULL )
 829             {
 830                 vlc_mutex_unlock( &p_sys->cache_lock );
 831                 return err_datum;
 832             }
 833
 834             memcpy( data.data, p_session->data, data.size );
 835             vlc_mutex_unlock( &p_sys->cache_lock );
 836             return data;
 837         }
 838         p_session++;
 839     }
 840
 841     vlc_mutex_unlock( &p_sys->cache_lock );
 842
 843     return err_datum;
 844 }
 845
 846
 847 static int cb_delete( void *p_server, gnutls_datum key )
 848 {
 849     tls_server_sys_t *p_sys = ((tls_server_t *)p_server)->p_sys;
 850     saved_session_t *p_session, *p_end;
 851
 852     p_session = p_sys->p_cache;
 853     p_end = p_session + p_sys->i_cache_size;
 854
 855     vlc_mutex_lock( &p_sys->cache_lock );
 856
 857     while( p_session < p_end )
 858     {
 859         if( ( p_session->i_idlen == key.size )
 860          && !memcmp( p_session->id, key.data, key.size ) )
 861         {
 862             p_session->i_datalen = p_session->i_idlen = 0;
 863             vlc_mutex_unlock( &p_sys->cache_lock );
 864             return 0;
 865         }
 866         p_session++;
 867     }
 868
 869     vlc_mutex_unlock( &p_sys->cache_lock );
 870
 871     return -1;
 872 }
 873
 874
 875 /**
 876  * Initializes a server-side TLS session.
 877  */
 878 static tls_session_t *
 879 gnutls_ServerSessionPrepare( tls_server_t *p_server )
 880 {
 881     tls_session_t *p_session;
 882     tls_server_sys_t *p_server_sys;
 883     gnutls_session session;
 884     int i_val;
 885
 886     p_session = vlc_object_create( p_server, sizeof (struct tls_session_t) );
 887     if( p_session == NULL )
 888         return NULL;
 889
 890     p_session->p_sys = malloc( sizeof(struct tls_session_sys_t) );
 891     if( p_session->p_sys == NULL )
 892     {
 893         vlc_object_destroy( p_session );
 894         return NULL;
 895     }
 896
 897     vlc_object_attach( p_session, p_server );
 898
 899     p_server_sys = (tls_server_sys_t *)p_server->p_sys;
 900     p_session->sock.p_sys = p_session;
 901     p_session->sock.pf_send = gnutls_Send;
 902     p_session->sock.pf_recv = gnutls_Recv;
 903     p_session->pf_handshake = gnutls_BeginHandshake;
 904     p_session->pf_handshake2 = p_server_sys->pf_handshake2;
 905     p_session->pf_close = gnutls_SessionClose;
 906
 907     ((tls_session_sys_t *)p_session->p_sys)->b_handshaked = VLC_FALSE;
 908     ((tls_session_sys_t *)p_session->p_sys)->psz_hostname = NULL;
 909
 910     i_val = gnutls_init( &session, GNUTLS_SERVER );
 911     if( i_val != 0 )
 912     {
 913         msg_Err( p_server, "cannot initialize TLS session: %s",
 914                  gnutls_strerror( i_val ) );
 915         goto error;
 916     }
 917
 918     ((tls_session_sys_t *)p_session->p_sys)->session = session;
 919
 920     if (gnutls_SessionPrioritize (VLC_OBJECT (p_session), session))
 921     {
 922         gnutls_deinit( session );
 923         goto error;
 924     }
 925
 926     i_val = gnutls_credentials_set( session, GNUTLS_CRD_CERTIFICATE,
 927                                     p_server_sys->x509_cred );
 928     if( i_val < 0 )
 929     {
 930         msg_Err( p_server, "cannot set TLS session credentials: %s",
 931                  gnutls_strerror( i_val ) );
 932         gnutls_deinit( session );
 933         goto error;
 934     }
 935
 936     if( p_session->pf_handshake2 == gnutls_HandshakeAndValidate )
 937         gnutls_certificate_server_set_request( session, GNUTLS_CERT_REQUIRE );
 938
 939     i_val = config_GetInt (p_server, "gnutls-dh-bits");
 940     gnutls_dh_set_prime_bits (session, i_val);
 941
 942     /* Session resumption support */
 943     i_val = config_GetInt (p_server, "gnutls-cache-expiration");
 944     gnutls_db_set_cache_expiration (session, i_val);
 945     gnutls_db_set_retrieve_function( session, cb_fetch );
 946     gnutls_db_set_remove_function( session, cb_delete );
 947     gnutls_db_set_store_function( session, cb_store );
 948     gnutls_db_set_ptr( session, p_server );
 949
 950     return p_session;
 951
 952 error:
 953     free( p_session->p_sys );
 954     vlc_object_detach( p_session );
 955     vlc_object_destroy( p_session );
 956     return NULL;
 957 }
 958
 959
 960 /**
 961  * Releases data allocated with tls_ServerCreate().
 962  */
 963 static void
 964 gnutls_ServerDelete( tls_server_t *p_server )
 965 {
 966     tls_server_sys_t *p_sys;
 967     p_sys = (tls_server_sys_t *)p_server->p_sys;
 968
 969     vlc_mutex_destroy( &p_sys->cache_lock );
 970     free( p_sys->p_cache );
 971
 972     vlc_object_detach( p_server );
 973     vlc_object_destroy( p_server );
 974
 975     /* all sessions depending on the server are now deinitialized */
 976     gnutls_certificate_free_credentials( p_sys->x509_cred );
 977     gnutls_dh_params_deinit( p_sys->dh_params );
 978     free( p_sys );
 979 }
 980
 981
 982 /**
 983  * Adds one or more certificate authorities.
 984  *
 985  * @param psz_ca_path (Unicode) path to an x509 certificates list.
 986  *
 987  * @return -1 on error, 0 on success.
 988  *****************************************************************************/
 989 static int
 990 gnutls_ServerAddCA( tls_server_t *p_server, const char *psz_ca_path )
 991 {
 992     tls_server_sys_t *p_sys;
 993     char *psz_local_path;
 994     int val;
 995
 996     p_sys = (tls_server_sys_t *)(p_server->p_sys);
 997
 998     psz_local_path = ToLocale( psz_ca_path );
 999     val = gnutls_certificate_set_x509_trust_file( p_sys->x509_cred,
1000                                                   psz_local_path,
1001                                                   GNUTLS_X509_FMT_PEM );
1002     LocaleFree( psz_local_path );
1003     if( val < 0 )
1004     {
1005         msg_Err( p_server, "cannot add trusted CA (%s): %s", psz_ca_path,
1006                  gnutls_strerror( val ) );
1007         return VLC_EGENERIC;
1008     }
1009     msg_Dbg( p_server, " %d trusted CA added (%s)", val, psz_ca_path );
1010
1011     /* enables peer's certificate verification */
1012     p_sys->pf_handshake2 = gnutls_HandshakeAndValidate;
1013
1014     return VLC_SUCCESS;
1015 }
1016
1017
1018 /**
1019  * Adds a certificates revocation list to be sent to TLS clients.
1020  *
1021  * @param psz_crl_path (Unicode) path of the CRL file.
1022  *
1023  * @return -1 on error, 0 on success.
1024  */
1025 static int
1026 gnutls_ServerAddCRL( tls_server_t *p_server, const char *psz_crl_path )
1027 {
1028     int val;
1029     char *psz_local_path = ToLocale( psz_crl_path );
1030
1031     val = gnutls_certificate_set_x509_crl_file( ((tls_server_sys_t *)
1032                                                 (p_server->p_sys))->x509_cred,
1033                                                 psz_local_path,
1034                                                 GNUTLS_X509_FMT_PEM );
1035     LocaleFree( psz_crl_path );
1036     if( val < 0 )
1037     {
1038         msg_Err( p_server, "cannot add CRL (%s): %s", psz_crl_path,
1039                  gnutls_strerror( val ) );
1040         return VLC_EGENERIC;
1041     }
1042     msg_Dbg( p_server, "%d CRL added (%s)", val, psz_crl_path );
1043     return VLC_SUCCESS;
1044 }
1045
1046
1047 /**
1048  * Allocates a whole server's TLS credentials.
1049  *
1050  * @return NULL on error.
1051  */
1052 static tls_server_t *
1053 gnutls_ServerCreate( tls_t *p_tls, const char *psz_cert_path,
1054                      const char *psz_key_path )
1055 {
1056     tls_server_t *p_server;
1057     tls_server_sys_t *p_sys;
1058     char *psz_local_key, *psz_local_cert;
1059     int val;
1060
1061     msg_Dbg( p_tls, "creating TLS server" );
1062
1063     p_sys = (tls_server_sys_t *)malloc( sizeof(struct tls_server_sys_t) );
1064     if( p_sys == NULL )
1065         return NULL;
1066
1067     p_sys->i_cache_size = config_GetInt (p_tls, "gnutls-cache-size");
1068     p_sys->p_cache = (struct saved_session_t *)calloc( p_sys->i_cache_size,
1069                                            sizeof( struct saved_session_t ) );
1070     if( p_sys->p_cache == NULL )
1071     {
1072         free( p_sys );
1073         return NULL;
1074     }
1075     p_sys->p_store = p_sys->p_cache;
1076
1077     p_server = vlc_object_create( p_tls, sizeof(struct tls_server_t) );
1078     if( p_server == NULL )
1079     {
1080         free( p_sys->p_cache );
1081         free( p_sys );
1082         return NULL;
1083     }
1084
1085     vlc_object_attach( p_server, p_tls );
1086
1087     p_server->p_sys = p_sys;
1088     p_server->pf_delete = gnutls_ServerDelete;
1089     p_server->pf_add_CA = gnutls_ServerAddCA;
1090     p_server->pf_add_CRL = gnutls_ServerAddCRL;
1091     p_server->pf_session_prepare = gnutls_ServerSessionPrepare;
1092
1093     /* No certificate validation by default */
1094     p_sys->pf_handshake2 = gnutls_ContinueHandshake;
1095
1096     vlc_mutex_init( p_server, &p_sys->cache_lock );
1097
1098     /* Sets server's credentials */
1099     val = gnutls_certificate_allocate_credentials( &p_sys->x509_cred );
1100     if( val != 0 )
1101     {
1102         msg_Err( p_server, "cannot allocate X509 credentials: %s",
1103                  gnutls_strerror( val ) );
1104         goto error;
1105     }
1106
1107     psz_local_cert = ToLocale( psz_cert_path );
1108     psz_local_key = ToLocale( psz_key_path );
1109     val = gnutls_certificate_set_x509_key_file( p_sys->x509_cred,
1110                                                 psz_local_cert, psz_local_key,
1111                                                 GNUTLS_X509_FMT_PEM );
1112     LocaleFree( psz_cert_path );
1113     LocaleFree( psz_key_path );
1114     if( val < 0 )
1115     {
1116         msg_Err( p_server, "cannot set certificate chain or private key: %s",
1117                  gnutls_strerror( val ) );
1118         gnutls_certificate_free_credentials( p_sys->x509_cred );
1119         goto error;
1120     }
1121
1122     /* FIXME:
1123      * - regenerate these regularly
1124      * - support other ciper suites
1125      */
1126     val = gnutls_dh_params_init( &p_sys->dh_params );
1127     if( val >= 0 )
1128     {
1129         msg_Dbg( p_server, "computing Diffie Hellman ciphers parameters" );
1130         val = gnutls_dh_params_generate2( p_sys->dh_params,
1131                                           config_GetInt( p_tls, "gnutls-dh-bits" ) );
1132     }
1133     if( val < 0 )
1134     {
1135         msg_Err( p_server, "cannot initialize DH cipher suites: %s",
1136                  gnutls_strerror( val ) );
1137         gnutls_certificate_free_credentials( p_sys->x509_cred );
1138         goto error;
1139     }
1140     msg_Dbg( p_server, "ciphers parameters computed" );
1141
1142     gnutls_certificate_set_dh_params( p_sys->x509_cred, p_sys->dh_params);
1143
1144     return p_server;
1145
1146 error:
1147     vlc_mutex_destroy( &p_sys->cache_lock );
1148     vlc_object_detach( p_server );
1149     vlc_object_destroy( p_server );
1150     free( p_sys );
1151     return NULL;
1152 }
1153
1154
1155 #ifdef LIBVLC_USE_PTHREAD
1156 GCRY_THREAD_OPTION_PTHREAD_IMPL;
1157 # define gcry_threads_vlc gcry_threads_pthread
1158 #else
1159 /**
1160  * gcrypt thread option VLC implementation
1161  */
1162
1163 # define NEED_THREAD_CONTEXT 1
1164 static vlc_object_t *__p_gcry_data;
1165
1166 static int gcry_vlc_mutex_init( void **p_sys )
1167 {
1168     int i_val;
1169     vlc_mutex_t *p_lock = (vlc_mutex_t *)malloc( sizeof( vlc_mutex_t ) );
1170
1171     if( p_lock == NULL)
1172         return ENOMEM;
1173
1174     i_val = vlc_mutex_init( __p_gcry_data, p_lock );
1175     if( i_val )
1176         free( p_lock );
1177     else
1178         *p_sys = p_lock;
1179     return i_val;
1180 }
1181
1182 static int gcry_vlc_mutex_destroy( void **p_sys )
1183 {
1184     int i_val;
1185     vlc_mutex_t *p_lock = (vlc_mutex_t *)*p_sys;
1186
1187     i_val = vlc_mutex_destroy( p_lock );
1188     free( p_lock );
1189     return i_val;
1190 }
1191
1192 static int gcry_vlc_mutex_lock( void **p_sys )
1193 {
1194     return vlc_mutex_lock( (vlc_mutex_t *)*p_sys );
1195 }
1196
1197 static int gcry_vlc_mutex_unlock( void **lock )
1198 {
1199     return vlc_mutex_unlock( (vlc_mutex_t *)*lock );
1200 }
1201
1202 static struct gcry_thread_cbs gcry_threads_vlc =
1203 {
1204     GCRY_THREAD_OPTION_USER,
1205     NULL,
1206     gcry_vlc_mutex_init,
1207     gcry_vlc_mutex_destroy,
1208     gcry_vlc_mutex_lock,
1209     gcry_vlc_mutex_unlock
1210 };
1211 #endif
1212
1213
1214 /*****************************************************************************
1215  * Module initialization
1216  *****************************************************************************/
1217 static unsigned refs = 0;
1218
1219 static int
1220 Open( vlc_object_t *p_this )
1221 {
1222     tls_t *p_tls = (tls_t *)p_this;
1223     vlc_mutex_t *lock;
1224
1225     lock = var_GetGlobalMutex( "gnutls_mutex" );
1226     vlc_mutex_lock( lock );
1227
1228     /* Initialize GnuTLS only once */
1229     if( refs == 0 )
1230     {
1231 #ifdef NEED_THREAD_CONTEXT
1232         __p_gcry_data = VLC_OBJECT( p_this->p_libvlc );
1233 #endif
1234
1235         gcry_control (GCRYCTL_SET_THREAD_CBS, &gcry_threads_vlc);
1236         if( gnutls_global_init( ) )
1237         {
1238             msg_Warn( p_this, "cannot initialize GnuTLS" );
1239             vlc_mutex_unlock( lock );
1240             return VLC_EGENERIC;
1241         }
1242
1243         const char *psz_version = gnutls_check_version( "1.2.9" );
1244         if( psz_version == NULL )
1245         {
1246             gnutls_global_deinit( );
1247             vlc_mutex_unlock( lock );
1248             msg_Err( p_this, "unsupported GnuTLS version" );
1249             return VLC_EGENERIC;
1250         }
1251         msg_Dbg( p_this, "GnuTLS v%s initialized", psz_version );
1252     }
1253
1254     refs++;
1255     vlc_mutex_unlock( lock );
1256
1257     p_tls->pf_server_create = gnutls_ServerCreate;
1258     p_tls->pf_client_create = gnutls_ClientCreate;
1259     return VLC_SUCCESS;
1260 }
1261
1262
1263 /*****************************************************************************
1264  * Module deinitialization
1265  *****************************************************************************/
1266 static void
1267 Close( vlc_object_t *p_this )
1268 {
1269     /*tls_t *p_tls = (tls_t *)p_this;
1270     tls_sys_t *p_sys = (tls_sys_t *)(p_this->p_sys);*/
1271
1272     vlc_mutex_t *lock;
1273
1274     lock = var_GetGlobalMutex( "gnutls_mutex" );
1275     vlc_mutex_lock( lock );
1276
1277     if( --refs == 0 )
1278     {
1279         gnutls_global_deinit( );
1280         msg_Dbg( p_this, "GnuTLS deinitialized" );
1281     }
1282
1283     vlc_mutex_unlock( lock );
1284 }