src/modules/rlm_eap/types/rlm_eap_ttls/ttls.c

   1 /*
   2  * rlm_eap_ttls.c  contains the interfaces that are called from eap
   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 2003 Alan DeKok <aland@freeradius.org>
  21  */
  22 #include "eap_ttls.h"
  23
  24 /*
  25  *    0                   1                   2                   3
  26  *    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  27  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  28  *   |                           AVP Code                            |
  29  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  30  *   |V M r r r r r r|                  AVP Length                   |
  31  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  32  *   |                        Vendor-ID (opt)                        |
  33  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  34  *   |    Data ...
  35  *   +-+-+-+-+-+-+-+-+
  36  */
  37
  38 /*
  39  *      Verify that the diameter packet is valid.
  40  */
  41 static int diameter_verify(const uint8_t *data, unsigned int data_len)
  42 {
  43         uint32_t attr;
  44         uint32_t length;
  45         unsigned int offset;
  46         unsigned int data_left = data_len;
  47
  48         while (data_left > 0) {
  49                 rad_assert(data_left <= data_len);
  50                 memcpy(&attr, data, sizeof(attr));
  51                 data += 4;
  52                 attr = ntohl(attr);
  53                 if (attr > 255) {
  54                         DEBUG2("  rlm_eap_ttls:  Non-RADIUS attribute in tunneled authentication is not supported");
  55                         return 0;
  56                 }
  57
  58                 memcpy(&length, data , sizeof(length));
  59                 data += 4;
  60                 length = ntohl(length);
  61
  62                 /*
  63                  *      A "vendor" flag, with a vendor ID of zero,
  64                  *      is equivalent to no vendor.  This is stupid.
  65                  */
  66                 offset = 8;
  67                 if ((length & (1 << 31)) != 0) {
  68                         int attribute;
  69                         uint32_t vendor;
  70                         DICT_ATTR *da;
  71
  72                         memcpy(&vendor, data, sizeof(vendor));
  73                         vendor = ntohl(vendor);
  74
  75                         if (vendor > 65535) {
  76                                 DEBUG2("  rlm_eap_ttls: Vendor codes larger than 65535 are not supported");
  77                                 return 0;
  78                         }
  79
  80                         attribute = (vendor << 16) | attr;
  81
  82                         da = dict_attrbyvalue(attribute);
  83
  84                         /*
  85                          *      SHOULD check ((length & (1 << 30)) != 0)
  86                          *      for the mandatory bit.
  87                          */
  88                         if (!da) {
  89                                 DEBUG2("  rlm_eap_ttls: Fatal! Vendor %u, Attribute %u was not found in our dictionary. ",
  90                                        vendor, attr);
  91                                 return 0;
  92                         }
  93
  94                         data += 4; /* skip the vendor field */
  95                         offset += 4; /* offset to value field */
  96                 }
  97
  98                 /*
  99                  *      Ignore the M bit.  We support all RADIUS attributes...
 100                  */
 101
 102                 /*
 103                  *      Get the length.  If it's too big, die.
 104                  */
 105                 length &= 0x00ffffff;
 106
 107                 /*
 108                  *      Too short or too long is bad.
 109                  *
 110                  *      FIXME: EAP-Message
 111                  */
 112                 if (length < offset) {
 113                         DEBUG2("  rlm_eap_ttls: Tunneled attribute %d is too short (%d)to contain anything useful.", attr, length);
 114                         return 0;
 115                 }
 116
 117                 if (length > (MAX_STRING_LEN + 8)) {
 118                         DEBUG2("  rlm_eap_ttls: Tunneled attribute %d is too long (%d) to pack into a RADIUS attribute.", attr, length);
 119                         return 0;
 120                 }
 121
 122                 if (length > data_left) {
 123                         DEBUG2("  rlm_eap_ttls: Tunneled attribute %d is longer than room left in the packet (%d > %d).", attr, length, data_left);
 124                         return 0;
 125                 }
 126
 127                 /*
 128                  *      Check for broken implementations, which don't
 129                  *      pad the AVP to a 4-octet boundary.
 130                  */
 131                 if (data_left == length) break;
 132
 133                 /*
 134                  *      The length does NOT include the padding, so
 135                  *      we've got to account for it here by rounding up
 136                  *      to the nearest 4-byte boundary.
 137                  */
 138                 length += 0x03;
 139                 length &= ~0x03;
 140
 141                 /*
 142                  *      If the rest of the diameter packet is larger than
 143                  *      this attribute, continue.
 144                  *
 145                  *      Otherwise, if the attribute over-flows the end
 146                  *      of the packet, die.
 147                  */
 148                 if (data_left < length) {
 149                         DEBUG2("  rlm_eap_ttls: ERROR! Diameter attribute overflows packet!");
 150                         return 0;
 151                 }
 152
 153                 /*
 154                  *      Check again for equality, now that we're padded
 155                  *      length to a multiple of 4 octets.
 156                  */
 157                 if (data_left == length) break;
 158
 159                 /*
 160                  *      data_left > length, continue.
 161                  */
 162                 data_left -= length;
 163                 data += length - offset;
 164         }
 165
 166         /*
 167          *      We got this far.  It looks OK.
 168          */
 169         return 1;
 170 }
 171
 172
 173 /*
 174  *      Convert diameter attributes to our VALUE_PAIR's
 175  */
 176 static VALUE_PAIR *diameter2vp(SSL *ssl,
 177                                const uint8_t *data, unsigned int data_len)
 178 {
 179         uint32_t        attr;
 180         uint32_t        length;
 181         unsigned int    offset;
 182         int             size;
 183         unsigned int    data_left = data_len;
 184         VALUE_PAIR      *first = NULL;
 185         VALUE_PAIR      **last = &first;
 186         VALUE_PAIR      *vp;
 187
 188         while (data_left > 0) {
 189                 rad_assert(data_left <= data_len);
 190                 memcpy(&attr, data, sizeof(attr));
 191                 data += 4;
 192                 attr = ntohl(attr);
 193
 194                 memcpy(&length, data, sizeof(length));
 195                 data += 4;
 196                 length = ntohl(length);
 197
 198                 /*
 199                  *      Ignore the M bit.  We support all RADIUS attributes...
 200                  */
 201
 202                 /*
 203                  *      A "vendor" flag, with a vendor ID of zero,
 204                  *      is equivalent to no vendor.  This is stupid.
 205                  */
 206                 offset = 8;
 207                 if ((length & (1 << 31)) != 0) {
 208                         uint32_t vendor;
 209
 210                         memcpy(&vendor, data, sizeof(vendor));
 211                         vendor = ntohl(vendor);
 212
 213                         attr |= (vendor << 16);
 214
 215                         data += 4; /* skip the vendor field, it's zero */
 216                         offset += 4; /* offset to value field */
 217                 }
 218
 219                 /*
 220                  *      Get the length.
 221                  */
 222                 length &= 0x00ffffff;
 223
 224                 /*
 225                  *      diameter code + length, and it must fit in
 226                  *      a VALUE_PAIR.
 227                  */
 228                 rad_assert(length <= (offset + MAX_STRING_LEN));
 229
 230                 /*
 231                  *      Get the size of the value portion of the
 232                  *      attribute.
 233                  */
 234                 size = length - offset;
 235
 236                 /*
 237                  *      Create it.
 238                  */
 239                 vp = paircreate(attr, PW_TYPE_OCTETS);
 240                 if (!vp) {
 241                         DEBUG2("  rlm_eap_ttls: Failure in creating VP");
 242                         pairfree(&first);
 243                         return NULL;
 244                 }
 245
 246                 /*
 247                  *      If it's a type from our dictionary, then
 248                  *      we need to put the data in a relevant place.
 249                  */
 250                 switch (vp->type) {
 251                 case PW_TYPE_INTEGER:
 252                 case PW_TYPE_DATE:
 253                         if (size != vp->length) {
 254                                 DEBUG2("  rlm_eap_ttls: Invalid length attribute %d",
 255                                        attr);
 256                                 pairfree(&first);
 257                                 return NULL;
 258                         }
 259                         memcpy(&vp->lvalue, data, vp->length);
 260
 261                         /*
 262                          *      Stored in host byte order: change it.
 263                          */
 264                         vp->lvalue = ntohl(vp->lvalue);
 265                         break;
 266
 267                 case PW_TYPE_IPADDR:
 268                         if (size != vp->length) {
 269                                 DEBUG2("  rlm_eap_ttls: Invalid length attribute %d",
 270                                        attr);
 271                                 pairfree(&first);
 272                                 return NULL;
 273                         }
 274                   memcpy(&vp->lvalue, data, vp->length);
 275
 276                   /*
 277                    *    Stored in network byte order: don't change it.
 278                    */
 279                   break;
 280
 281                   /*
 282                    *    String, octet, etc.  Copy the data from the
 283                    *    value field over verbatim.
 284                    *
 285                    *    FIXME: Ipv6 attributes ?
 286                    *
 287                    */
 288                 default:
 289                         vp->length = size;
 290                         memcpy(vp->vp_strvalue, data, vp->length);
 291                         break;
 292                 }
 293
 294                 /*
 295                  *      User-Password is NUL padded to a multiple
 296                  *      of 16 bytes.  Let's chop it to something
 297                  *      more reasonable.
 298                  *
 299                  *      NOTE: This means that the User-Password
 300                  *      attribute CANNOT EVER have embedded zeros in it!
 301                  */
 302                 switch (vp->attribute) {
 303                 case PW_USER_PASSWORD:
 304                         rad_assert(vp->length <= 128); /* RFC requirements */
 305
 306                         /*
 307                          *      If the password is exactly 16 octets,
 308                          *      it won't be zero-terminated.
 309                          */
 310                         vp->vp_strvalue[vp->length] = '\0';
 311                         vp->length = strlen(vp->vp_strvalue);
 312                         break;
 313
 314                         /*
 315                          *      Ensure that the client is using the
 316                          *      correct challenge.  This weirdness is
 317                          *      to protect against against replay
 318                          *      attacks, where anyone observing the
 319                          *      CHAP exchange could pose as that user,
 320                          *      by simply choosing to use the same
 321                          *      challenge.
 322                          *
 323                          *      By using a challenge based on
 324                          *      information from the current session,
 325                          *      we can guarantee that the client is
 326                          *      not *choosing* a challenge.
 327                          *
 328                          *      We're a little forgiving in that we
 329                          *      have loose checks on the length, and
 330                          *      we do NOT check the Id (first octet of
 331                          *      the response to the challenge)
 332                          *
 333                          *      But if the client gets the challenge correct,
 334                          *      we're not too worried about the Id.
 335                          */
 336                 case PW_CHAP_CHALLENGE:
 337                 case PW_MSCHAP_CHALLENGE:
 338                         if ((vp->length < 8) ||
 339                             (vp->length > 16)) {
 340                                 DEBUG2("  TTLS: Tunneled challenge has invalid length");
 341                                 pairfree(&first);
 342                                 return NULL;
 343
 344                         } else {
 345                                 int i;
 346                                 uint8_t challenge[16];
 347
 348                                 eapttls_gen_challenge(ssl, challenge,
 349                                                       sizeof(challenge));
 350
 351                                 for (i = 0; i < vp->length; i++) {
 352                                         if (challenge[i] != vp->vp_strvalue[i]) {
 353                                                 DEBUG2("  TTLS: Tunneled challenge is incorrect");
 354                                                 pairfree(&first);
 355                                                 return NULL;
 356                                         }
 357                                 }
 358                         }
 359                         break;
 360
 361                 default:
 362                         break;
 363                 } /* switch over checking/re-writing of attributes. */
 364
 365                 /*
 366                  *      Update the list.
 367                  */
 368                 *last = vp;
 369                 last = &(vp->next);
 370
 371                 /*
 372                  *      Catch non-aligned attributes.
 373                  */
 374                 if (data_left == length) break;
 375
 376                 /*
 377                  *      The length does NOT include the padding, so
 378                  *      we've got to account for it here by rounding up
 379                  *      to the nearest 4-byte boundary.
 380                  */
 381                 length += 0x03;
 382                 length &= ~0x03;
 383
 384                 rad_assert(data_left >= length);
 385                 data_left -= length;
 386                 data += length - offset; /* already updated */
 387         }
 388
 389         /*
 390          *      We got this far.  It looks OK.
 391          */
 392         return first;
 393 }
 394
 395 /*
 396  *      Convert VALUE_PAIR's to diameter attributes, and write them
 397  *      to an SSL session.
 398  *
 399  *      The ONLY VALUE_PAIR's which may be passed to this function
 400  *      are ones which can go inside of a RADIUS (i.e. diameter)
 401  *      packet.  So no server-configuration attributes, or the like.
 402  */
 403 static int vp2diameter(tls_session_t *tls_session, VALUE_PAIR *first)
 404 {
 405         /*
 406          *      RADIUS packets are no more than 4k in size, so if
 407          *      we've got more than 4k of data to write, it's very
 408          *      bad.
 409          */
 410         uint8_t         buffer[4096];
 411         uint8_t         *p;
 412         uint32_t        attr;
 413         uint32_t        length;
 414         uint32_t        vendor;
 415         size_t          total;
 416         VALUE_PAIR      *vp;
 417
 418         p = buffer;
 419         total = 0;
 420
 421         for (vp = first; vp != NULL; vp = vp->next) {
 422                 /*
 423                  *      Too much data: die.
 424                  */
 425                 if ((total + vp->length + 12) >= sizeof(buffer)) {
 426                         DEBUG2("  TTLS output buffer is full!");
 427                         return 0;
 428                 }
 429
 430                 /*
 431                  *      Hmm... we don't group multiple EAP-Messages
 432                  *      together.  Maybe we should...
 433                  */
 434
 435                 /*
 436                  *      Length is no more than 253, due to RADIUS
 437                  *      issues.
 438                  */
 439                 length = vp->length;
 440                 vendor = (vp->attribute >> 16) & 0xffff;
 441                 if (vendor != 0) {
 442                         attr = vp->attribute & 0xffff;
 443                         length |= (1 << 31);
 444                 } else {
 445                         attr = vp->attribute;
 446                 }
 447
 448                 /*
 449                  *      Hmm... set the M bit for all attributes?
 450                  */
 451                 length |= (1 << 30);
 452
 453                 attr = ntohl(attr);
 454
 455                 memcpy(p, &attr, sizeof(attr));
 456                 p += 4;
 457                 total += 4;
 458
 459                 length += 8;    /* includes 8 bytes of attr & length */
 460
 461                 if (vendor != 0) {
 462                         length += 4; /* include 4 bytes of vendor */
 463
 464                         length = ntohl(length);
 465                         memcpy(p, &length, sizeof(length));
 466                         p += 4;
 467                         total += 4;
 468
 469                         vendor = ntohl(vendor);
 470                         memcpy(p, &vendor, sizeof(vendor));
 471                         p += 4;
 472                         total += 4;
 473                 } else {
 474                         length = ntohl(length);
 475                         memcpy(p, &length, sizeof(length));
 476                         p += 4;
 477                         total += 4;
 478                 }
 479
 480                 switch (vp->type) {
 481                 case PW_TYPE_INTEGER:
 482                 case PW_TYPE_DATE:
 483                         attr = ntohl(vp->lvalue); /* stored in host order */
 484                         memcpy(p, &attr, sizeof(attr));
 485                         length = 4;
 486                         break;
 487
 488                 case PW_TYPE_IPADDR:
 489                         attr = vp->lvalue; /* stored in network order */
 490                         memcpy(p, &attr, sizeof(attr));
 491                         length = 4;
 492                         break;
 493
 494                 case PW_TYPE_STRING:
 495                 case PW_TYPE_OCTETS:
 496                 default:
 497                         memcpy(p, vp->vp_strvalue, vp->length);
 498                         length = vp->length;
 499                         break;
 500                 }
 501
 502                 /*
 503                  *      Skip to the end of the data.
 504                  */
 505                 p += length;
 506                 total += length;
 507
 508                 /*
 509                  *      Align the data to a multiple of 4 bytes.
 510                  */
 511                 if ((total & 0x03) != 0) {
 512                         unsigned int i;
 513
 514                         length = 4 - (total & 0x03);
 515                         for (i = 0; i < length; i++) {
 516                                 *p = '\0';
 517                                 p++;
 518                                 total++;
 519                         }
 520                 }
 521         } /* loop over the VP's to write. */
 522
 523         /*
 524          *      Write the data in the buffer to the SSL session.
 525          */
 526         if (total > 0) {
 527 #ifndef NDEBUG
 528                 unsigned int i;
 529
 530                 if (debug_flag > 2) {
 531                         for (i = 0; i < total; i++) {
 532                                 if ((i & 0x0f) == 0) printf("  TTLS tunnel data out %04x: ", i);
 533
 534                                 printf("%02x ", buffer[i]);
 535
 536                                 if ((i & 0x0f) == 0x0f) printf("\n");
 537                         }
 538                         if ((total & 0x0f) != 0) printf("\n");
 539                 }
 540 #endif
 541
 542                 (tls_session->record_plus)(&tls_session->clean_in, buffer, total);
 543
 544                 /*
 545                  *      FIXME: Check the return code.
 546                  */
 547                 tls_handshake_send(tls_session);
 548         }
 549
 550         /*
 551          *      Everything's OK.
 552          */
 553         return 1;
 554 }
 555
 556 /*
 557  *      Use a reply packet to determine what to do.
 558  */
 559 static int process_reply(EAP_HANDLER *handler, tls_session_t *tls_session,
 560                          REQUEST *request, RADIUS_PACKET *reply)
 561 {
 562         int rcode = RLM_MODULE_REJECT;
 563         VALUE_PAIR *vp;
 564         ttls_tunnel_t *t = tls_session->opaque;
 565
 566         handler = handler;      /* -Wunused */
 567
 568         /*
 569          *      If the response packet was Access-Accept, then
 570          *      we're OK.  If not, die horribly.
 571          *
 572          *      FIXME: Take MS-CHAP2-Success attribute, and
 573          *      tunnel it back to the client, to authenticate
 574          *      ourselves to the client.
 575          *
 576          *      FIXME: If we have an Access-Challenge, then
 577          *      the Reply-Message is tunneled back to the client.
 578          *
 579          *      FIXME: If we have an EAP-Message, then that message
 580          *      must be tunneled back to the client.
 581          *
 582          *      FIXME: If we have an Access-Challenge with a State
 583          *      attribute, then do we tunnel that to the client, or
 584          *      keep track of it ourselves?
 585          *
 586          *      FIXME: EAP-Messages can only start with 'identity',
 587          *      NOT 'eap start', so we should check for that....
 588          */
 589         switch (reply->code) {
 590         case PW_AUTHENTICATION_ACK:
 591                 DEBUG2("  TTLS: Got tunneled Access-Accept");
 592
 593                 rcode = RLM_MODULE_OK;
 594
 595                 /*
 596                  *      MS-CHAP2-Success means that we do NOT return
 597                  *      an Access-Accept, but instead tunnel that
 598                  *      attribute to the client, and keep going with
 599                  *      the TTLS session.  Once the client accepts
 600                  *      our identity, it will respond with an empty
 601                  *      packet, and we will send EAP-Success.
 602                  */
 603                 vp = NULL;
 604                 pairmove2(&vp, &reply->vps, PW_MSCHAP2_SUCCESS);
 605                 if (vp) {
 606 #if 1
 607                         /*
 608                          *      FIXME: Tunneling MS-CHAP2-Success causes
 609                          *      the only client we have access to, to die.
 610                          *
 611                          *      We don't want that...
 612                          */
 613                         pairfree(&vp);
 614 #else
 615                         DEBUG2("  TTLS: Got MS-CHAP2-Success, tunneling it to the client in a challenge.");
 616                         rcode = RLM_MODULE_HANDLED;
 617                         t->authenticated = TRUE;
 618 #endif
 619                 } else { /* no MS-CHAP2-Success */
 620                         /*
 621                          *      Can only have EAP-Message if there's
 622                          *      no MS-CHAP2-Success.  (FIXME: EAP-MSCHAP?)
 623                          *
 624                          *      We also do NOT tunnel the EAP-Success
 625                          *      attribute back to the client, as the client
 626                          *      can figure it out, from the non-tunneled
 627                          *      EAP-Success packet.
 628                          */
 629                         pairmove2(&vp, &reply->vps, PW_EAP_MESSAGE);
 630                         pairfree(&vp);
 631                 }
 632
 633                 /*
 634                  *      Handle the ACK, by tunneling any necessary reply
 635                  *      VP's back to the client.
 636                  */
 637                 if (vp) {
 638                         vp2diameter(tls_session, vp);
 639                         pairfree(&vp);
 640                 }
 641
 642                 /*
 643                  *      If we've been told to use the attributes from
 644                  *      the reply, then do so.
 645                  *
 646                  *      WARNING: This may leak information about the
 647                  *      tunneled user!
 648                  */
 649                 if (t->use_tunneled_reply) {
 650                         pairdelete(&reply->vps, PW_PROXY_STATE);
 651                         pairadd(&request->reply->vps, reply->vps);
 652                         reply->vps = NULL;
 653                 }
 654                 break;
 655
 656
 657         case PW_AUTHENTICATION_REJECT:
 658                 DEBUG2("  TTLS: Got tunneled Access-Reject");
 659                 rcode = RLM_MODULE_REJECT;
 660                 break;
 661
 662                 /*
 663                  *      Handle Access-Challenge, but only if we
 664                  *      send tunneled reply data.  This is because
 665                  *      an Access-Challenge means that we MUST tunnel
 666                  *      a Reply-Message to the client.
 667                  */
 668         case PW_ACCESS_CHALLENGE:
 669                 DEBUG2("  TTLS: Got tunneled Access-Challenge");
 670
 671                 /*
 672                  *      Keep the State attribute, if necessary.
 673                  *
 674                  *      Get rid of the old State, too.
 675                  */
 676                 pairfree(&t->state);
 677                 pairmove2(&t->state, &reply->vps, PW_STATE);
 678
 679                 /*
 680                  *      We should really be a bit smarter about this,
 681                  *      and move over only those attributes which
 682                  *      are relevant to the authentication request,
 683                  *      but that's a lot more work, and this "dumb"
 684                  *      method works in 99.9% of the situations.
 685                  */
 686                 vp = NULL;
 687                 pairmove2(&vp, &reply->vps, PW_EAP_MESSAGE);
 688
 689                 /*
 690                  *      There MUST be a Reply-Message in the challenge,
 691                  *      which we tunnel back to the client.
 692                  *
 693                  *      If there isn't one in the reply VP's, then
 694                  *      we MUST create one, with an empty string as
 695                  *      it's value.
 696                  */
 697                 pairmove2(&vp, &reply->vps, PW_REPLY_MESSAGE);
 698
 699                 /*
 700                  *      Handle the ACK, by tunneling any necessary reply
 701                  *      VP's back to the client.
 702                  */
 703                 if (vp) {
 704                         vp2diameter(tls_session, vp);
 705                         pairfree(&vp);
 706                 }
 707                 rcode = RLM_MODULE_HANDLED;
 708                 break;
 709
 710         default:
 711                 DEBUG2("  TTLS: Unknown RADIUS packet type %d: rejecting tunneled user", reply->code);
 712                 rcode = RLM_MODULE_INVALID;
 713                 break;
 714         }
 715
 716         return rcode;
 717 }
 718
 719
 720 /*
 721  *      Do post-proxy processing,
 722  */
 723 static int eapttls_postproxy(EAP_HANDLER *handler, void *data)
 724 {
 725         int rcode;
 726         tls_session_t *tls_session = (tls_session_t *) data;
 727         REQUEST *fake;
 728
 729         DEBUG2("  TTLS: Passing reply from proxy back into the tunnel.");
 730
 731         /*
 732          *      If there was a fake request associated with the proxied
 733          *      request, do more processing of it.
 734          */
 735         fake = (REQUEST *) request_data_get(handler->request,
 736                                             handler->request->proxy,
 737                                             REQUEST_DATA_EAP_MSCHAP_TUNNEL_CALLBACK);
 738
 739         /*
 740          *      Do the callback, if it exists, and if it was a success.
 741          */
 742         if (fake && (handler->request->proxy_reply->code == PW_AUTHENTICATION_ACK)) {
 743                 VALUE_PAIR *vp;
 744                 REQUEST *request = handler->request;
 745
 746                 /*
 747                  *      Terrible hacks.
 748                  */
 749                 rad_assert(fake->packet == NULL);
 750                 fake->packet = request->proxy;
 751                 request->proxy = NULL;
 752
 753                 rad_assert(fake->reply == NULL);
 754                 fake->reply = request->proxy_reply;
 755                 request->proxy_reply = NULL;
 756
 757                 /*
 758                  *      Perform a post-auth stage for the tunneled
 759                  *      session.
 760                  */
 761                 fake->options &= ~RAD_REQUEST_OPTION_PROXY_EAP;
 762                 rcode = rad_postauth(fake);
 763                 DEBUG2("  POST-AUTH %d", rcode);
 764
 765 #ifndef NDEBUG
 766                 if (debug_flag > 0) {
 767                         printf("  TTLS: Final reply from tunneled session code %d\n",
 768                                fake->reply->code);
 769
 770                         for (vp = fake->reply->vps; vp != NULL; vp = vp->next) {
 771                                 putchar('\t');vp_print(stdout, vp);putchar('\n');
 772                         }
 773                 }
 774 #endif
 775
 776                 /*
 777                  *      Terrible hacks.
 778                  */
 779                 request->proxy = fake->packet;
 780                 fake->packet = NULL;
 781                 request->proxy_reply = fake->reply;
 782                 fake->reply = NULL;
 783
 784                 /*
 785                  *      And we're done with this request.
 786                  */
 787
 788                 switch (rcode) {
 789                 case RLM_MODULE_FAIL:
 790                         request_free(&fake);
 791                         eaptls_fail(handler->eap_ds, 0);
 792                         return 0;
 793                         break;
 794
 795                 default:  /* Don't Do Anything */
 796                         DEBUG2(" TTLS: Got reply %d",
 797                                request->proxy_reply->code);
 798                         break;
 799                 }
 800         }
 801         request_free(&fake);    /* robust if fake == NULL */
 802
 803         /*
 804          *      Process the reply from the home server.
 805          */
 806         rcode = process_reply(handler, tls_session, handler->request,
 807                               handler->request->proxy_reply);
 808
 809         /*
 810          *      The proxy code uses the reply from the home server as
 811          *      the basis for the reply to the NAS.  We don't want that,
 812          *      so we toss it, after we've had our way with it.
 813          */
 814         pairfree(&handler->request->proxy_reply->vps);
 815
 816         switch (rcode) {
 817         case RLM_MODULE_REJECT:
 818                 DEBUG2("  TTLS: Reply was rejected");
 819                 break;
 820
 821         case RLM_MODULE_HANDLED:
 822                 DEBUG2("  TTLS: Reply was handled");
 823                 eaptls_request(handler->eap_ds, tls_session);
 824                 return 1;
 825
 826         case RLM_MODULE_OK:
 827                 DEBUG2("  TTLS: Reply was OK");
 828                 eaptls_success(handler->eap_ds, 0);
 829                 eaptls_gen_mppe_keys(&handler->request->reply->vps,
 830                                      tls_session->ssl,
 831                                      "ttls keying material");
 832                 return 1;
 833
 834         default:
 835                 DEBUG2("  TTLS: Reply was unknown.");
 836                 break;
 837         }
 838
 839         eaptls_fail(handler->eap_ds, 0);
 840         return 0;
 841 }
 842
 843
 844 /*
 845  *      Free a request.
 846  */
 847 static void my_request_free(void *data)
 848 {
 849         REQUEST *request = (REQUEST *)data;
 850
 851         request_free(&request);
 852 }
 853
 854
 855 /*
 856  *      Process the "diameter" contents of the tunneled data.
 857  */
 858 int eapttls_process(EAP_HANDLER *handler, tls_session_t *tls_session)
 859 {
 860         int err;
 861         int rcode = PW_AUTHENTICATION_REJECT;
 862         REQUEST *fake;
 863         VALUE_PAIR *vp;
 864         ttls_tunnel_t *t;
 865         const uint8_t *data;
 866         unsigned int data_len;
 867         char buffer[1024];
 868         REQUEST *request = handler->request;
 869
 870         /*
 871          *      Grab the dirty data, and copy it to our buffer.
 872          *
 873          *      I *really* don't like these 'record_t' things...
 874          */
 875         data_len = (tls_session->record_minus)(&tls_session->dirty_in, buffer, sizeof(buffer));
 876         data = buffer;
 877
 878         /*
 879          *      Write the data from the dirty buffer (i.e. packet
 880          *      data) into the buffer which we will give to SSL for
 881          *      decoding.
 882          *
 883          *      Some of this code COULD technically go into the TLS
 884          *      module, in eaptls_process(), where it returns EAPTLS_OK.
 885          *
 886          *      Similarly, the writing of data to the SSL context could
 887          *      go there, too...
 888          */
 889         BIO_write(tls_session->into_ssl, buffer, data_len);
 890         (tls_session->record_init)(&tls_session->clean_out);
 891
 892         /*
 893          *      Read (and decrypt) the tunneled data from the SSL session,
 894          *      and put it into the decrypted data buffer.
 895          */
 896         err = SSL_read(tls_session->ssl, tls_session->clean_out.data,
 897                        sizeof(tls_session->clean_out.data));
 898         if (err < 0) {
 899                 /*
 900                  *      FIXME: Call SSL_get_error() to see what went
 901                  *      wrong.
 902                  */
 903                 radlog(L_INFO, "rlm_eap_ttls: SSL_read Error");
 904                 return PW_AUTHENTICATION_REJECT;
 905         }
 906
 907         t = (ttls_tunnel_t *) tls_session->opaque;
 908
 909         /*
 910          *      If there's no data, maybe this is an ACK to an
 911          *      MS-CHAP2-Success.
 912          */
 913         if (err == 0) {
 914                 if (t->authenticated) {
 915                         DEBUG2("  TTLS: Got ACK, and the user was already authenticated.");
 916                         return PW_AUTHENTICATION_ACK;
 917                 } /* else no session, no data, die. */
 918
 919                 /*
 920                  *      FIXME: Call SSL_get_error() to see what went
 921                  *      wrong.
 922                  */
 923                 radlog(L_INFO, "rlm_eap_ttls: SSL_read Error");
 924                 return PW_AUTHENTICATION_REJECT;
 925         }
 926
 927         data_len = tls_session->clean_out.used = err;
 928         data = tls_session->clean_out.data;
 929
 930 #ifndef NDEBUG
 931         if (debug_flag > 2) {
 932                 unsigned int i;
 933
 934                 for (i = 0; i < data_len; i++) {
 935                         if ((i & 0x0f) == 0) printf("  TTLS tunnel data in %04x: ", i);
 936
 937                         printf("%02x ", data[i]);
 938
 939                         if ((i & 0x0f) == 0x0f) printf("\n");
 940                 }
 941                 if ((data_len & 0x0f) != 0) printf("\n");
 942         }
 943 #endif
 944
 945         if (!diameter_verify(data, data_len)) {
 946                 return PW_AUTHENTICATION_REJECT;
 947         }
 948
 949         /*
 950          *      Allocate a fake REQUEST structe.
 951          */
 952         fake = request_alloc_fake(request);
 953
 954         rad_assert(fake->packet->vps == NULL);
 955
 956         /*
 957          *      Add the tunneled attributes to the fake request.
 958          */
 959         fake->packet->vps = diameter2vp(tls_session->ssl, data, data_len);
 960         if (!fake->packet->vps) {
 961                 return PW_AUTHENTICATION_REJECT;
 962         }
 963
 964         /*
 965          *      Tell the request that it's a fake one.
 966          */
 967         vp = pairmake("Freeradius-Proxied-To", "127.0.0.1", T_OP_EQ);
 968         if (vp) {
 969                 pairadd(&fake->packet->vps, vp);
 970         }
 971
 972 #ifndef NDEBUG
 973         if (debug_flag > 0) {
 974                 printf("  TTLS: Got tunneled request\n");
 975
 976                 for (vp = fake->packet->vps; vp != NULL; vp = vp->next) {
 977                         putchar('\t');vp_print(stdout, vp);putchar('\n');
 978                 }
 979         }
 980 #endif
 981
 982         /*
 983          *      Update other items in the REQUEST data structure.
 984          */
 985         fake->username = pairfind(fake->packet->vps, PW_USER_NAME);
 986         fake->password = pairfind(fake->packet->vps, PW_PASSWORD);
 987
 988         /*
 989          *      No User-Name, try to create one from stored data.
 990          */
 991         if (!fake->username) {
 992                 /*
 993                  *      No User-Name in the stored data, look for
 994                  *      an EAP-Identity, and pull it out of there.
 995                  */
 996                 if (!t->username) {
 997                         vp = pairfind(fake->packet->vps, PW_EAP_MESSAGE);
 998                         if (vp &&
 999                             (vp->length >= EAP_HEADER_LEN + 2) &&
1000                             (vp->vp_strvalue[0] == PW_EAP_RESPONSE) &&
1001                             (vp->vp_strvalue[EAP_HEADER_LEN] == PW_EAP_IDENTITY) &&
1002                             (vp->vp_strvalue[EAP_HEADER_LEN + 1] != 0)) {
1003                                 /*
1004                                  *      Create & remember a User-Name
1005                                  */
1006                                 t->username = pairmake("User-Name", "", T_OP_EQ);
1007                                 rad_assert(t->username != NULL);
1008
1009                                 memcpy(t->username->vp_strvalue, vp->vp_strvalue + 5,
1010                                        vp->length - 5);
1011                                 t->username->length = vp->length - 5;
1012                                 t->username->vp_strvalue[t->username->length] = 0;
1013
1014                                 DEBUG2("  TTLS: Got tunneled identity of %s",
1015                                        t->username->vp_strvalue);
1016
1017                                 /*
1018                                  *      If there's a default EAP type,
1019                                  *      set it here.
1020                                  */
1021                                 if (t->default_eap_type != 0) {
1022                                         DEBUG2("  TTLS: Setting default EAP type for tunneled EAP session.");
1023                                         vp = paircreate(PW_EAP_TYPE,
1024                                                         PW_TYPE_INTEGER);
1025                                         rad_assert(vp != NULL);
1026                                         vp->lvalue = t->default_eap_type;
1027                                         pairadd(&fake->config_items, vp);
1028                                 }
1029
1030                         } else {
1031                                 /*
1032                                  *      Don't reject the request outright,
1033                                  *      as it's permitted to do EAP without
1034                                  *      user-name.
1035                                  */
1036                                 DEBUG2("  rlm_eap_ttls: WARNING! No EAP-Identity found to start EAP conversation.");
1037                         }
1038                 } /* else there WAS a t->username */
1039
1040                 if (t->username) {
1041                         vp = paircopy(t->username);
1042                         pairadd(&fake->packet->vps, vp);
1043                         fake->username = pairfind(fake->packet->vps, PW_USER_NAME);
1044                 }
1045         } /* else the request ALREADY had a User-Name */
1046
1047         /*
1048          *      Add the State attribute, too, if it exists.
1049          */
1050         if (t->state) {
1051                 DEBUG2("  TTLS: Adding old state with %02x %02x",
1052                        t->state->vp_strvalue[0], t->state->vp_strvalue[1]);
1053                 vp = paircopy(t->state);
1054                 if (vp) pairadd(&fake->packet->vps, vp);
1055         }
1056
1057         /*
1058          *      If this is set, we copy SOME of the request attributes
1059          *      from outside of the tunnel to inside of the tunnel.
1060          *
1061          *      We copy ONLY those attributes which do NOT already
1062          *      exist in the tunneled request.
1063          */
1064         if (t->copy_request_to_tunnel) {
1065                 VALUE_PAIR *copy;
1066
1067                 for (vp = request->packet->vps; vp != NULL; vp = vp->next) {
1068                         /*
1069                          *      The attribute is a server-side thingy,
1070                          *      don't copy it.
1071                          */
1072                         if ((vp->attribute > 255) &&
1073                             (((vp->attribute >> 16) & 0xffff) == 0)) {
1074                                 continue;
1075                         }
1076
1077                         /*
1078                          *      The outside attribute is already in the
1079                          *      tunnel, don't copy it.
1080                          *
1081                          *      This works for BOTH attributes which
1082                          *      are originally in the tunneled request,
1083                          *      AND attributes which are copied there
1084                          *      from below.
1085                          */
1086                         if (pairfind(fake->packet->vps, vp->attribute)) {
1087                                 continue;
1088                         }
1089
1090                         /*
1091                          *      Some attributes are handled specially.
1092                          */
1093                         switch (vp->attribute) {
1094                                 /*
1095                                  *      NEVER copy Message-Authenticator,
1096                                  *      EAP-Message, or State.  They're
1097                                  *      only for outside of the tunnel.
1098                                  */
1099                         case PW_USER_NAME:
1100                         case PW_USER_PASSWORD:
1101                         case PW_CHAP_PASSWORD:
1102                         case PW_CHAP_CHALLENGE:
1103                         case PW_PROXY_STATE:
1104                         case PW_MESSAGE_AUTHENTICATOR:
1105                         case PW_EAP_MESSAGE:
1106                         case PW_STATE:
1107                                 continue;
1108                                 break;
1109
1110                                 /*
1111                                  *      By default, copy it over.
1112                                  */
1113                         default:
1114                                 break;
1115                         }
1116
1117                         /*
1118                          *      Don't copy from the head, we've already
1119                          *      checked it.
1120                          */
1121                         copy = paircopy2(vp, vp->attribute);
1122                         pairadd(&fake->packet->vps, copy);
1123                 }
1124         }
1125
1126 #ifndef NDEBUG
1127         if (debug_flag > 0) {
1128           printf("  TTLS: Sending tunneled request\n");
1129
1130           for (vp = fake->packet->vps; vp != NULL; vp = vp->next) {
1131             putchar('\t');vp_print(stdout, vp);putchar('\n');
1132           }
1133         }
1134 #endif
1135
1136         /*
1137          *      Call authentication recursively, which will
1138          *      do PAP, CHAP, MS-CHAP, etc.
1139          */
1140         rad_authenticate(fake);
1141
1142         /*
1143          *      Note that we don't do *anything* with the reply
1144          *      attributes.
1145          */
1146 #ifndef NDEBUG
1147         if (debug_flag > 0) {
1148           printf("  TTLS: Got tunneled reply RADIUS code %d\n",
1149                  fake->reply->code);
1150
1151           for (vp = fake->reply->vps; vp != NULL; vp = vp->next) {
1152             putchar('\t');vp_print(stdout, vp);putchar('\n');
1153           }
1154         }
1155 #endif
1156
1157         /*
1158          *      Decide what to do with the reply.
1159          */
1160         switch (fake->reply->code) {
1161         case 0:                 /* No reply code, must be proxied... */
1162                 vp = pairfind(fake->config_items, PW_PROXY_TO_REALM);
1163                 if (vp) {
1164                         eap_tunnel_data_t *tunnel;
1165                         DEBUG2("  TTLS: Tunneled authentication will be proxied to %s", vp->vp_strvalue);
1166
1167                         /*
1168                          *      Tell the original request that it's going
1169                          *      to be proxied.
1170                          */
1171                         pairmove2(&(request->config_items),
1172                                   &(fake->config_items),
1173                                   PW_PROXY_TO_REALM);
1174
1175                         /*
1176                          *      Seed the proxy packet with the
1177                          *      tunneled request.
1178                          */
1179                         rad_assert(request->proxy == NULL);
1180                         request->proxy = fake->packet;
1181                         fake->packet = NULL;
1182                         rad_free(&fake->reply);
1183                         fake->reply = NULL;
1184
1185                         /*
1186                          *      Set up the callbacks for the tunnel
1187                          */
1188                         tunnel = rad_malloc(sizeof(*tunnel));
1189                         memset(tunnel, 0, sizeof(*tunnel));
1190
1191                         tunnel->tls_session = tls_session;
1192                         tunnel->callback = eapttls_postproxy;
1193
1194                         /*
1195                          *      Associate the callback with the request.
1196                          */
1197                         rcode = request_data_add(request,
1198                                                  request->proxy,
1199                                                  REQUEST_DATA_EAP_TUNNEL_CALLBACK,
1200                                                  tunnel, free);
1201                         rad_assert(rcode == 0);
1202
1203                         /*
1204                          *      rlm_eap.c has taken care of associating
1205                          *      the handler with the fake request.
1206                          *
1207                          *      So we associate the fake request with
1208                          *      this request.
1209                          */
1210                         rcode = request_data_add(request,
1211                                                  request->proxy,
1212                                                  REQUEST_DATA_EAP_MSCHAP_TUNNEL_CALLBACK,
1213                                                  fake, my_request_free);
1214                         rad_assert(rcode == 0);
1215                         fake = NULL;
1216
1217                         /*
1218                          *      Didn't authenticate the packet, but
1219                          *      we're proxying it.
1220                          */
1221                         rcode = PW_STATUS_CLIENT;
1222
1223                 } else {
1224                         DEBUG2("  TTLS: No tunneled reply was found for request %d , and the request was not proxied: rejecting the user.",
1225                                request->number);
1226                         rcode = PW_AUTHENTICATION_REJECT;
1227                 }
1228                 break;
1229
1230         default:
1231                 /*
1232                  *      Returns RLM_MODULE_FOO, and we want to return
1233                  *      PW_FOO
1234                  */
1235                 rcode = process_reply(handler, tls_session, request,
1236                                       fake->reply);
1237                 switch (rcode) {
1238                 case RLM_MODULE_REJECT:
1239                         rcode = PW_AUTHENTICATION_REJECT;
1240                         break;
1241
1242                 case RLM_MODULE_HANDLED:
1243                         rcode = PW_ACCESS_CHALLENGE;
1244                         break;
1245
1246                 case RLM_MODULE_OK:
1247                         rcode = PW_AUTHENTICATION_ACK;
1248                         break;
1249
1250                 default:
1251                         rcode = PW_AUTHENTICATION_REJECT;
1252                         break;
1253                 }
1254                 break;
1255         }
1256
1257         request_free(&fake);
1258
1259         return rcode;
1260 }