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