src/modules/rlm_eap/libeap/tls.c

   1 /*
   2  * tls.c
   3  *
   4  * Version:     $Id$
   5  *
   6  *   This program is free software; you can redistribute it and/or modify
   7  *   it under the terms of the GNU General Public License as published by
   8  *   the Free Software Foundation; either version 2 of the License, or
   9  *   (at your option) any later version.
  10  *
  11  *   This program is distributed in the hope that it will be useful,
  12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *   GNU General Public License for more details.
  15  *
  16  *   You should have received a copy of the GNU General Public License
  17  *   along with this program; if not, write to the Free Software
  18  *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  19  *
  20  * Copyright 2001  hereUare Communications, Inc. <raghud@hereuare.com>
  21  * Copyright 2003  Alan DeKok <aland@freeradius.org>
  22  * Copyright 2006  The FreeRADIUS server project
  23  */
  24
  25 #include <freeradius-devel/ident.h>
  26 RCSID("$Id$")
  27
  28 #include "eap_tls.h"
  29
  30 /* record */
  31 static void             record_init(record_t *buf);
  32 static void             record_close(record_t *buf);
  33 static unsigned int     record_plus(record_t *buf, const void *ptr,
  34                                     unsigned int size);
  35 static unsigned int     record_minus(record_t *buf, void *ptr,
  36                                      unsigned int size);
  37
  38 tls_session_t *eaptls_new_session(SSL_CTX *ssl_ctx, int client_cert)
  39 {
  40         tls_session_t *state = NULL;
  41         SSL *new_tls = NULL;
  42
  43         client_cert = client_cert; /* -Wunused.  See bug #350 */
  44
  45         if ((new_tls = SSL_new(ssl_ctx)) == NULL) {
  46                 radlog(L_ERR, "rlm_eap_tls: Error creating new SSL");
  47                 radlog(L_ERR, "rlm_eap: SSL error %s", ERR_error_string(ERR_get_error(), NULL));
  48                 return NULL;
  49         }
  50
  51         /* We use the SSL's "app_data" to indicate a call-back */
  52         SSL_set_app_data(new_tls, NULL);
  53
  54         state = (tls_session_t *)malloc(sizeof(*state));
  55         memset(state, 0, sizeof(*state));
  56         session_init(state);
  57         state->ssl = new_tls;
  58
  59         /*
  60          *      Initialize callbacks
  61          */
  62         state->record_init = record_init;
  63         state->record_close = record_close;
  64         state->record_plus = record_plus;
  65         state->record_minus = record_minus;
  66
  67         /*
  68          *      Create & hook the BIOs to handle the dirty side of the
  69          *      SSL.  This is *very important* as we want to handle
  70          *      the transmission part.  Now the only IO interface
  71          *      that SSL is aware of, is our defined BIO buffers.
  72          *
  73          *      This means that all SSL IO is done to/from memory,
  74          *      and we can update those BIOs from the EAP packets we've
  75          *      received.
  76          */
  77         state->into_ssl = BIO_new(BIO_s_mem());
  78         state->from_ssl = BIO_new(BIO_s_mem());
  79         SSL_set_bio(state->ssl, state->into_ssl, state->from_ssl);
  80
  81         /*
  82          *      Add the message callback to identify what type of
  83          *      message/handshake is passed
  84          */
  85         SSL_set_msg_callback(new_tls, cbtls_msg);
  86         SSL_set_msg_callback_arg(new_tls, state);
  87         SSL_set_info_callback(new_tls, cbtls_info);
  88
  89         /*
  90          *      In Server mode we only accept.
  91          */
  92         SSL_set_accept_state(state->ssl);
  93
  94         return state;
  95 }
  96
  97 /*
  98  *      Print out some text describing the error.
  99  */
 100 static int int_ssl_check(SSL *s, int ret, const char *text)
 101 {
 102         int e;
 103         unsigned long l;
 104
 105         if ((l = ERR_get_error()) != 0) {
 106                 radlog(L_ERR, "rlm_eap: SSL error %s",
 107                        ERR_error_string(l, NULL));
 108         }
 109         e = SSL_get_error(s, ret);
 110
 111         switch(e) {
 112                 /*
 113                  *      These seem to be harmless and already "dealt
 114                  *      with" by our non-blocking environment. NB:
 115                  *      "ZERO_RETURN" is the clean "error"
 116                  *      indicating a successfully closed SSL
 117                  *      tunnel. We let this happen because our IO
 118                  *      loop should not appear to have broken on
 119                  *      this condition - and outside the IO loop, the
 120                  *      "shutdown" state is checked.
 121                  *
 122                  *      Don't print anything if we ignore the error.
 123                  */
 124         case SSL_ERROR_NONE:
 125         case SSL_ERROR_WANT_READ:
 126         case SSL_ERROR_WANT_WRITE:
 127         case SSL_ERROR_WANT_X509_LOOKUP:
 128         case SSL_ERROR_ZERO_RETURN:
 129                 break;
 130
 131                 /*
 132                  *      These seem to be indications of a genuine
 133                  *      error that should result in the SSL tunnel
 134                  *      being regarded as "dead".
 135                  */
 136         case SSL_ERROR_SYSCALL:
 137                 radlog(L_ERR, "rlm_eap_tls: %s failed in a system call (%d), TLS session fails.",
 138                        text, ret);
 139                 return 0;
 140
 141         case SSL_ERROR_SSL:
 142                 radlog(L_ERR, "rlm_eap_tls: %s failed inside of TLS (%d), TLS session fails.",
 143                        text, ret);
 144                 return 0;
 145
 146         default:
 147                 /*
 148                  *      For any other errors that (a) exist, and (b)
 149                  *      crop up - we need to interpret what to do with
 150                  *      them - so "politely inform" the caller that
 151                  *      the code needs updating here.
 152                  */
 153                 radlog(L_ERR, "rlm_eap_tls: FATAL SSL error ..... %d\n", e);
 154                 return 0;
 155         }
 156
 157         return 1;
 158 }
 159
 160 /*
 161  * We are the server, we always get the dirty data
 162  * (Handshake data is also considered as dirty data)
 163  * During handshake, since SSL API handles itself,
 164  * After clean-up, dirty_out will be filled with
 165  * the data required for handshaking. So we check
 166  * if dirty_out is empty then we simply send it back.
 167  * As of now, if handshake is successful, then it is EAP-Success
 168  * or else EAP-failure should be sent
 169  *
 170  * Fill the Bio with the dirty data to clean it
 171  * Get the cleaned data from SSL, if it is not Handshake data
 172  */
 173 int tls_handshake_recv(tls_session_t *ssn)
 174 {
 175         int err;
 176
 177         BIO_write(ssn->into_ssl, ssn->dirty_in.data, ssn->dirty_in.used);
 178
 179         err = SSL_read(ssn->ssl, ssn->clean_out.data + ssn->clean_out.used,
 180                        sizeof(ssn->clean_out.data) - ssn->clean_out.used);
 181         if (err > 0) {
 182                 ssn->clean_out.used += err;
 183                 record_init(&ssn->dirty_in);
 184                 return 1;
 185         }
 186
 187         if (!int_ssl_check(ssn->ssl, err, "SSL_read")) {
 188                 return 0;
 189         }
 190
 191         /* Some Extra STATE information for easy debugging */
 192         if (SSL_is_init_finished(ssn->ssl)) {
 193                 DEBUG2("SSL Connection Established\n");
 194         }
 195         if (SSL_in_init(ssn->ssl)) {
 196                 DEBUG2("In SSL Handshake Phase\n");
 197         }
 198         if (SSL_in_before(ssn->ssl)) {
 199                 DEBUG2("Before SSL Handshake Phase\n");
 200         }
 201         if (SSL_in_accept_init(ssn->ssl)) {
 202                 DEBUG2("In SSL Accept mode \n");
 203         }
 204         if (SSL_in_connect_init(ssn->ssl)) {
 205                 DEBUG2("In SSL Connect mode \n");
 206         }
 207
 208         /*
 209          *      If we're finished the setup, and doing session
 210          *      resumption, (CCS and Finish received, parsed,
 211          *      and validated), wind up handshake.
 212          */
 213 #if 0
 214         if (SSL_is_init_finished(ssn->ssl) && (ssn->ssl->hit == 1)) {
 215                 record_init(&ssn->dirty_in);
 216
 217                 /*
 218                  *      Magic value. See eaptls_operation().
 219                  */
 220                 return 0xea;
 221
 222         }
 223 #endif
 224
 225         err = BIO_ctrl_pending(ssn->from_ssl);
 226         if (err > 0) {
 227                 err = BIO_read(ssn->from_ssl, ssn->dirty_out.data,
 228                                sizeof(ssn->dirty_out.data));
 229                 if (err > 0) {
 230                         ssn->dirty_out.used = err;
 231
 232                 } else if (BIO_should_retry(ssn->from_ssl)) {
 233                         record_init(&ssn->dirty_in);
 234                         DEBUG2("  tls: Asking for more data in tunnel");
 235                         return 1;
 236
 237                 } else {
 238                         int_ssl_check(ssn->ssl, err, "BIO_read");
 239                         record_init(&ssn->dirty_in);
 240                         return 0;
 241                 }
 242         } else {
 243                 DEBUG2("rlm_eap_tls: Application Data");
 244                 /* Its clean application data, do whatever we want */
 245                 record_init(&ssn->clean_out);
 246         }
 247
 248         /* We are done with dirty_in, reinitialize it */
 249         record_init(&ssn->dirty_in);
 250         return 1;
 251 }
 252
 253 /*
 254  *      Take clear-text user data, and encrypt it into the output buffer,
 255  *      to send to the client at the other end of the SSL connection.
 256  */
 257 int tls_handshake_send(tls_session_t *ssn)
 258 {
 259         int err;
 260
 261         /*
 262          *      If there's un-encrypted data in 'clean_in', then write
 263          *      that data to the SSL session, and then call the BIO function
 264          *      to get that encrypted data from the SSL session, into
 265          *      a buffer which we can then package into an EAP packet.
 266          *
 267          *      Based on Server's logic this clean_in is expected to
 268          *      contain the data to send to the client.
 269          */
 270         if (ssn->clean_in.used > 0) {
 271                 int written;
 272
 273                 written = SSL_write(ssn->ssl, ssn->clean_in.data, ssn->clean_in.used);
 274                 record_minus(&ssn->clean_in, NULL, written);
 275
 276
 277                 /* Get the dirty data from Bio to send it */
 278                 err = BIO_read(ssn->from_ssl, ssn->dirty_out.data,
 279                                sizeof(ssn->dirty_out.data));
 280                 if (err > 0) {
 281                         ssn->dirty_out.used = err;
 282                 } else {
 283                         int_ssl_check(ssn->ssl, err, "handshake_send");
 284                 }
 285         }
 286
 287         return 1;
 288 }
 289
 290 void session_init(tls_session_t *ssn)
 291 {
 292         ssn->ssl = NULL;
 293         ssn->into_ssl = ssn->from_ssl = NULL;
 294         record_init(&ssn->clean_in);
 295         record_init(&ssn->clean_out);
 296         record_init(&ssn->dirty_in);
 297         record_init(&ssn->dirty_out);
 298
 299         memset(&ssn->info, 0, sizeof(ssn->info));
 300
 301         ssn->offset = 0;
 302         ssn->fragment = 0;
 303         ssn->tls_msg_len = 0;
 304         ssn->length_flag = 0;
 305         ssn->opaque = NULL;
 306         ssn->free_opaque = NULL;
 307 }
 308
 309 void session_close(tls_session_t *ssn)
 310 {
 311         if(ssn->ssl)
 312                 SSL_free(ssn->ssl);
 313 #if 0
 314 /*
 315  * WARNING: SSL_free seems to decrement the reference counts already,
 316  *      so doing this might crash the application.
 317  */
 318         if(ssn->into_ssl)
 319                 BIO_free(ssn->into_ssl);
 320         if(ssn->from_ssl)
 321                 BIO_free(ssn->from_ssl);
 322 #endif
 323         record_close(&ssn->clean_in);
 324         record_close(&ssn->clean_out);
 325         record_close(&ssn->dirty_in);
 326         record_close(&ssn->dirty_out);
 327         session_init(ssn);
 328 }
 329
 330 void session_free(void *ssn)
 331 {
 332         tls_session_t *sess = (tls_session_t *)ssn;
 333
 334         if (!ssn) return;
 335
 336         /*
 337          *      Free any opaque TTLS or PEAP data.
 338          */
 339         if ((sess->opaque) && (sess->free_opaque)) {
 340                 sess->free_opaque(sess->opaque);
 341                 sess->opaque = NULL;
 342         }
 343
 344         session_close(sess);
 345
 346         free(sess);
 347 }
 348
 349 static void record_init(record_t *rec)
 350 {
 351         rec->used = 0;
 352 }
 353
 354 static void record_close(record_t *rec)
 355 {
 356         rec->used = 0;
 357 }
 358
 359
 360 /*
 361  *      Copy data to the intermediate buffer, before we send
 362  *      it somewhere.
 363  */
 364 static unsigned int record_plus(record_t *rec, const void *ptr,
 365                                 unsigned int size)
 366 {
 367         unsigned int added = MAX_RECORD_SIZE - rec->used;
 368
 369         if(added > size)
 370                 added = size;
 371         if(added == 0)
 372                 return 0;
 373         memcpy(rec->data + rec->used, ptr, added);
 374         rec->used += added;
 375         return added;
 376 }
 377
 378 /*
 379  *      Take data from the buffer, and give it to the caller.
 380  */
 381 static unsigned int record_minus(record_t *rec, void *ptr,
 382                                  unsigned int size)
 383 {
 384         unsigned int taken = rec->used;
 385
 386         if(taken > size)
 387                 taken = size;
 388         if(taken == 0)
 389                 return 0;
 390         if(ptr)
 391                 memcpy(ptr, rec->data, taken);
 392         rec->used -= taken;
 393
 394         /*
 395          *      This is pretty bad...
 396          */
 397         if(rec->used > 0)
 398                 memmove(rec->data, rec->data + taken, rec->used);
 399         return taken;
 400 }
 401
 402 void tls_session_information(tls_session_t *tls_session)
 403 {
 404         const char *str_write_p, *str_version, *str_content_type = "";
 405         const char *str_details1 = "", *str_details2= "";
 406         EAP_HANDLER *handler;
 407         REQUEST *request;
 408
 409         /*
 410          *      Don't print this out in the normal course of
 411          *      operations.
 412          */
 413         if (debug_flag == 0) {
 414                 return;
 415         }
 416
 417         str_write_p = tls_session->info.origin ? ">>>" : "<<<";
 418
 419         switch (tls_session->info.version)
 420         {
 421         case SSL2_VERSION:
 422                 str_version = "SSL 2.0";
 423                 break;
 424         case SSL3_VERSION:
 425                 str_version = "SSL 3.0 ";
 426                 break;
 427         case TLS1_VERSION:
 428                 str_version = "TLS 1.0 ";
 429                 break;
 430         default:
 431                 str_version = "Unknown TLS version";
 432                 break;
 433         }
 434
 435         if (tls_session->info.version == SSL3_VERSION ||
 436             tls_session->info.version == TLS1_VERSION) {
 437                 switch (tls_session->info.content_type) {
 438                 case SSL3_RT_CHANGE_CIPHER_SPEC:
 439                         str_content_type = "ChangeCipherSpec";
 440                         break;
 441                 case SSL3_RT_ALERT:
 442                         str_content_type = "Alert";
 443                         break;
 444                 case SSL3_RT_HANDSHAKE:
 445                         str_content_type = "Handshake";
 446                         break;
 447                 case SSL3_RT_APPLICATION_DATA:
 448                         str_content_type = "ApplicationData";
 449                         break;
 450                 default:
 451                         str_content_type = "UnknownContentType";
 452                         break;
 453                 }
 454
 455                 if (tls_session->info.content_type == SSL3_RT_ALERT) {
 456                         str_details1 = ", ???";
 457
 458                         if (tls_session->info.record_len == 2) {
 459
 460                                 switch (tls_session->info.alert_level) {
 461                                 case SSL3_AL_WARNING:
 462                                         str_details1 = ", warning";
 463                                         break;
 464                                 case SSL3_AL_FATAL:
 465                                         str_details1 = ", fatal";
 466                                         break;
 467                                 }
 468
 469                                 str_details2 = " ???";
 470                                 switch (tls_session->info.alert_description) {
 471                                 case SSL3_AD_CLOSE_NOTIFY:
 472                                         str_details2 = " close_notify";
 473                                         break;
 474                                 case SSL3_AD_UNEXPECTED_MESSAGE:
 475                                         str_details2 = " unexpected_message";
 476                                         break;
 477                                 case SSL3_AD_BAD_RECORD_MAC:
 478                                         str_details2 = " bad_record_mac";
 479                                         break;
 480                                 case TLS1_AD_DECRYPTION_FAILED:
 481                                         str_details2 = " decryption_failed";
 482                                         break;
 483                                 case TLS1_AD_RECORD_OVERFLOW:
 484                                         str_details2 = " record_overflow";
 485                                         break;
 486                                 case SSL3_AD_DECOMPRESSION_FAILURE:
 487                                         str_details2 = " decompression_failure";
 488                                         break;
 489                                 case SSL3_AD_HANDSHAKE_FAILURE:
 490                                         str_details2 = " handshake_failure";
 491                                         break;
 492                                 case SSL3_AD_BAD_CERTIFICATE:
 493                                         str_details2 = " bad_certificate";
 494                                         break;
 495                                 case SSL3_AD_UNSUPPORTED_CERTIFICATE:
 496                                         str_details2 = " unsupported_certificate";
 497                                         break;
 498                                 case SSL3_AD_CERTIFICATE_REVOKED:
 499                                         str_details2 = " certificate_revoked";
 500                                         break;
 501                                 case SSL3_AD_CERTIFICATE_EXPIRED:
 502                                         str_details2 = " certificate_expired";
 503                                         break;
 504                                 case SSL3_AD_CERTIFICATE_UNKNOWN:
 505                                         str_details2 = " certificate_unknown";
 506                                         break;
 507                                 case SSL3_AD_ILLEGAL_PARAMETER:
 508                                         str_details2 = " illegal_parameter";
 509                                         break;
 510                                 case TLS1_AD_UNKNOWN_CA:
 511                                         str_details2 = " unknown_ca";
 512                                         break;
 513                                 case TLS1_AD_ACCESS_DENIED:
 514                                         str_details2 = " access_denied";
 515                                         break;
 516                                 case TLS1_AD_DECODE_ERROR:
 517                                         str_details2 = " decode_error";
 518                                         break;
 519                                 case TLS1_AD_DECRYPT_ERROR:
 520                                         str_details2 = " decrypt_error";
 521                                         break;
 522                                 case TLS1_AD_EXPORT_RESTRICTION:
 523                                         str_details2 = " export_restriction";
 524                                         break;
 525                                 case TLS1_AD_PROTOCOL_VERSION:
 526                                         str_details2 = " protocol_version";
 527                                         break;
 528                                 case TLS1_AD_INSUFFICIENT_SECURITY:
 529                                         str_details2 = " insufficient_security";
 530                                         break;
 531                                 case TLS1_AD_INTERNAL_ERROR:
 532                                         str_details2 = " internal_error";
 533                                         break;
 534                                 case TLS1_AD_USER_CANCELLED:
 535                                         str_details2 = " user_canceled";
 536                                         break;
 537                                 case TLS1_AD_NO_RENEGOTIATION:
 538                                         str_details2 = " no_renegotiation";
 539                                         break;
 540                                 }
 541                         }
 542                 }
 543
 544                 if (tls_session->info.content_type == SSL3_RT_HANDSHAKE) {
 545                         str_details1 = "???";
 546
 547                         if (tls_session->info.record_len > 0)
 548                         switch (tls_session->info.handshake_type)
 549                         {
 550                         case SSL3_MT_HELLO_REQUEST:
 551                                 str_details1 = ", HelloRequest";
 552                                 break;
 553                         case SSL3_MT_CLIENT_HELLO:
 554                                 str_details1 = ", ClientHello";
 555                                 break;
 556                         case SSL3_MT_SERVER_HELLO:
 557                                 str_details1 = ", ServerHello";
 558                                 break;
 559                         case SSL3_MT_CERTIFICATE:
 560                                 str_details1 = ", Certificate";
 561                                 break;
 562                         case SSL3_MT_SERVER_KEY_EXCHANGE:
 563                                 str_details1 = ", ServerKeyExchange";
 564                                 break;
 565                         case SSL3_MT_CERTIFICATE_REQUEST:
 566                                 str_details1 = ", CertificateRequest";
 567                                 break;
 568                         case SSL3_MT_SERVER_DONE:
 569                                 str_details1 = ", ServerHelloDone";
 570                                 break;
 571                         case SSL3_MT_CERTIFICATE_VERIFY:
 572                                 str_details1 = ", CertificateVerify";
 573                                 break;
 574                         case SSL3_MT_CLIENT_KEY_EXCHANGE:
 575                                 str_details1 = ", ClientKeyExchange";
 576                                 break;
 577                         case SSL3_MT_FINISHED:
 578                                 str_details1 = ", Finished";
 579                                 break;
 580                         }
 581                 }
 582         }
 583
 584         snprintf(tls_session->info.info_description,
 585                  sizeof(tls_session->info.info_description),
 586                  "%s %s%s [length %04lx]%s%s\n",
 587                  str_write_p, str_version, str_content_type,
 588                  (unsigned long)tls_session->info.record_len,
 589                  str_details1, str_details2);
 590
 591         handler = (EAP_HANDLER *)SSL_get_ex_data(tls_session->ssl, 0);
 592         if (handler) {
 593                 request = handler->request;
 594         } else {
 595                 request = NULL;
 596         }
 597
 598         RDEBUG2("%s\n", tls_session->info.info_description);
 599 }