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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  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                 if (data_len < 12) {
  50                         DEBUG2("  rlm_eap_ttls:  Diameter attribute is too small to contain a Diameter header");
  51                         return 0;
  52                 }
  53
  54                 rad_assert(data_left <= data_len);
  55                 memcpy(&attr, data, sizeof(attr));
  56                 data += 4;
  57                 attr = ntohl(attr);
  58                 if (attr > 255) {
  59                         DEBUG2("  rlm_eap_ttls:  Non-RADIUS attribute in tunneled authentication is not supported");
  60                         return 0;
  61                 }
  62
  63                 memcpy(&length, data , sizeof(length));
  64                 data += 4;
  65                 length = ntohl(length);
  66
  67                 /*
  68                  *      A "vendor" flag, with a vendor ID of zero,
  69                  *      is equivalent to no vendor.  This is stupid.
  70                  */
  71                 offset = 8;
  72                 if ((length & (1 << 31)) != 0) {
  73                         int attribute;
  74                         uint32_t vendor;
  75                         DICT_ATTR *da;
  76
  77                         memcpy(&vendor, data, sizeof(vendor));
  78                         vendor = ntohl(vendor);
  79
  80                         if (vendor > 65535) {
  81                                 DEBUG2("  rlm_eap_ttls: Vendor codes larger than 65535 are not supported");
  82                                 return 0;
  83                         }
  84
  85                         attribute = (vendor << 16) | attr;
  86
  87                         da = dict_attrbyvalue(attribute);
  88
  89                         /*
  90                          *      SHOULD check ((length & (1 << 30)) != 0)
  91                          *      for the mandatory bit.
  92                          */
  93                         if (!da) {
  94                                 DEBUG2("  rlm_eap_ttls: Fatal! Vendor %u, Attribute %u was not found in our dictionary. ",
  95                                        vendor, attr);
  96                                 return 0;
  97                         }
  98
  99                         data += 4; /* skip the vendor field */
 100                         offset += 4; /* offset to value field */
 101                 }
 102
 103                 /*
 104                  *      Ignore the M bit.  We support all RADIUS attributes...
 105                  */
 106
 107                 /*
 108                  *      Get the length.  If it's too big, die.
 109                  */
 110                 length &= 0x00ffffff;
 111
 112                 /*
 113                  *      Too short or too long is bad.
 114                  *
 115                  *      FIXME: EAP-Message
 116                  */
 117                 if (length < offset) {
 118                         DEBUG2("  rlm_eap_ttls: Tunneled attribute %d is too short (%d)to contain anything useful.", attr, length);
 119                         return 0;
 120                 }
 121
 122                 if (length > (MAX_STRING_LEN + 8)) {
 123                         DEBUG2("  rlm_eap_ttls: Tunneled attribute %d is too long (%d) to pack into a RADIUS attribute.", attr, length);
 124                         return 0;
 125                 }
 126
 127                 if (length > data_left) {
 128                         DEBUG2("  rlm_eap_ttls: Tunneled attribute %d is longer than room left in the packet (%d > %d).", attr, length, data_left);
 129                         return 0;
 130                 }
 131
 132                 /*
 133                  *      Check for broken implementations, which don't
 134                  *      pad the AVP to a 4-octet boundary.
 135                  */
 136                 if (data_left == length) break;
 137
 138                 /*
 139                  *      The length does NOT include the padding, so
 140                  *      we've got to account for it here by rounding up
 141                  *      to the nearest 4-byte boundary.
 142                  */
 143                 length += 0x03;
 144                 length &= ~0x03;
 145
 146                 /*
 147                  *      If the rest of the diameter packet is larger than
 148                  *      this attribute, continue.
 149                  *
 150                  *      Otherwise, if the attribute over-flows the end
 151                  *      of the packet, die.
 152                  */
 153                 if (data_left < length) {
 154                         DEBUG2("  rlm_eap_ttls: ERROR! Diameter attribute overflows packet!");
 155                         return 0;
 156                 }
 157
 158                 /*
 159                  *      Check again for equality, now that we're padded
 160                  *      length to a multiple of 4 octets.
 161                  */
 162                 if (data_left == length) break;
 163
 164                 /*
 165                  *      data_left > length, continue.
 166                  */
 167                 data_left -= length;
 168                 data += length - offset;
 169         }
 170
 171         /*
 172          *      We got this far.  It looks OK.
 173          */
 174         return 1;
 175 }
 176
 177
 178 /*
 179  *      Convert diameter attributes to our VALUE_PAIR's
 180  */
 181 static VALUE_PAIR *diameter2vp(SSL *ssl,
 182                                const uint8_t *data, unsigned int data_len)
 183 {
 184         uint32_t        attr;
 185         uint32_t        length;
 186         unsigned int    offset;
 187         int             size;
 188         unsigned int    data_left = data_len;
 189         VALUE_PAIR      *first = NULL;
 190         VALUE_PAIR      **last = &first;
 191         VALUE_PAIR      *vp;
 192
 193         while (data_left > 0) {
 194                 rad_assert(data_left <= data_len);
 195                 memcpy(&attr, data, sizeof(attr));
 196                 data += 4;
 197                 attr = ntohl(attr);
 198
 199                 memcpy(&length, data, sizeof(length));
 200                 data += 4;
 201                 length = ntohl(length);
 202
 203                 /*
 204                  *      Ignore the M bit.  We support all RADIUS attributes...
 205                  */
 206
 207                 /*
 208                  *      A "vendor" flag, with a vendor ID of zero,
 209                  *      is equivalent to no vendor.  This is stupid.
 210                  */
 211                 offset = 8;
 212                 if ((length & (1 << 31)) != 0) {
 213                         uint32_t vendor;
 214
 215                         memcpy(&vendor, data, sizeof(vendor));
 216                         vendor = ntohl(vendor);
 217
 218                         attr |= (vendor << 16);
 219
 220                         data += 4; /* skip the vendor field, it's zero */
 221                         offset += 4; /* offset to value field */
 222                 }
 223
 224                 /*
 225                  *      Get the length.
 226                  */
 227                 length &= 0x00ffffff;
 228
 229                 /*
 230                  *      diameter code + length, and it must fit in
 231                  *      a VALUE_PAIR.
 232                  */
 233                 rad_assert(length <= (offset + MAX_STRING_LEN));
 234
 235                 /*
 236                  *      Get the size of the value portion of the
 237                  *      attribute.
 238                  */
 239                 size = length - offset;
 240
 241                 /*
 242                  *      Create it.
 243                  */
 244                 vp = paircreate(attr, PW_TYPE_OCTETS);
 245                 if (!vp) {
 246                         DEBUG2("  rlm_eap_ttls: Failure in creating VP");
 247                         pairfree(&first);
 248                         return NULL;
 249                 }
 250
 251                 /*
 252                  *      If it's a type from our dictionary, then
 253                  *      we need to put the data in a relevant place.
 254                  */
 255                 switch (vp->type) {
 256                 case PW_TYPE_INTEGER:
 257                 case PW_TYPE_DATE:
 258                         if (size != vp->length) {
 259                                 DEBUG2("  rlm_eap_ttls: Invalid length attribute %d",
 260                                        attr);
 261                                 pairfree(&first);
 262                                 pairfree(&vp);
 263                                 return NULL;
 264                         }
 265                         memcpy(&vp->lvalue, data, vp->length);
 266
 267                         /*
 268                          *      Stored in host byte order: change it.
 269                          */
 270                         vp->lvalue = ntohl(vp->lvalue);
 271                         break;
 272
 273                 case PW_TYPE_IPADDR:
 274                         if (size != vp->length) {
 275                                 DEBUG2("  rlm_eap_ttls: Invalid length attribute %d",
 276                                        attr);
 277                                 pairfree(&first);
 278                                 pairfree(&vp);
 279                                 return NULL;
 280                         }
 281                   memcpy(&vp->lvalue, data, vp->length);
 282
 283                   /*
 284                    *    Stored in network byte order: don't change it.
 285                    */
 286                   break;
 287
 288                   /*
 289                    *    String, octet, etc.  Copy the data from the
 290                    *    value field over verbatim.
 291                    *
 292                    *    FIXME: Ipv6 attributes ?
 293                    *
 294                    */
 295                 default:
 296                         vp->length = size;
 297                         memcpy(vp->strvalue, data, vp->length);
 298                         break;
 299                 }
 300
 301                 /*
 302                  *      User-Password is NUL padded to a multiple
 303                  *      of 16 bytes.  Let's chop it to something
 304                  *      more reasonable.
 305                  *
 306                  *      NOTE: This means that the User-Password
 307                  *      attribute CANNOT EVER have embedded zeros in it!
 308                  */
 309                 switch (vp->attribute) {
 310                 case PW_USER_PASSWORD:
 311                         rad_assert(vp->length <= 128); /* RFC requirements */
 312
 313                         /*
 314                          *      If the password is exactly 16 octets,
 315                          *      it won't be zero-terminated.
 316                          */
 317                         vp->strvalue[vp->length] = '\0';
 318                         vp->length = strlen(vp->strvalue);
 319                         break;
 320
 321                         /*
 322                          *      Ensure that the client is using the
 323                          *      correct challenge.  This weirdness is
 324                          *      to protect against against replay
 325                          *      attacks, where anyone observing the
 326                          *      CHAP exchange could pose as that user,
 327                          *      by simply choosing to use the same
 328                          *      challenge.
 329                          *
 330                          *      By using a challenge based on
 331                          *      information from the current session,
 332                          *      we can guarantee that the client is
 333                          *      not *choosing* a challenge.
 334                          *
 335                          *      We're a little forgiving in that we
 336                          *      have loose checks on the length, and
 337                          *      we do NOT check the Id (first octet of
 338                          *      the response to the challenge)
 339                          *
 340                          *      But if the client gets the challenge correct,
 341                          *      we're not too worried about the Id.
 342                          */
 343                 case PW_CHAP_CHALLENGE:
 344                 case PW_MSCHAP_CHALLENGE:
 345                         if ((vp->length < 8) ||
 346                             (vp->length > 16)) {
 347                                 DEBUG2("  TTLS: Tunneled challenge has invalid length");
 348                                 pairfree(&first);
 349                                 pairfree(&vp);
 350                                 return NULL;
 351
 352                         } else {
 353                                 int i;
 354                                 uint8_t challenge[16];
 355
 356                                 eapttls_gen_challenge(ssl, challenge,
 357                                                       sizeof(challenge));
 358
 359                                 for (i = 0; i < vp->length; i++) {
 360                                         if (challenge[i] != vp->strvalue[i]) {
 361                                                 DEBUG2("  TTLS: Tunneled challenge is incorrect");
 362                                                 pairfree(&first);
 363                                                 pairfree(&vp);
 364                                                 return NULL;
 365                                         }
 366                                 }
 367                         }
 368                         break;
 369
 370                 default:
 371                         break;
 372                 } /* switch over checking/re-writing of attributes. */
 373
 374                 /*
 375                  *      Update the list.
 376                  */
 377                 *last = vp;
 378                 last = &(vp->next);
 379
 380                 /*
 381                  *      Catch non-aligned attributes.
 382                  */
 383                 if (data_left == length) break;
 384
 385                 /*
 386                  *      The length does NOT include the padding, so
 387                  *      we've got to account for it here by rounding up
 388                  *      to the nearest 4-byte boundary.
 389                  */
 390                 length += 0x03;
 391                 length &= ~0x03;
 392
 393                 rad_assert(data_left >= length);
 394                 data_left -= length;
 395                 data += length - offset; /* already updated */
 396         }
 397
 398         /*
 399          *      We got this far.  It looks OK.
 400          */
 401         return first;
 402 }
 403
 404 /*
 405  *      Convert VALUE_PAIR's to diameter attributes, and write them
 406  *      to an SSL session.
 407  *
 408  *      The ONLY VALUE_PAIR's which may be passed to this function
 409  *      are ones which can go inside of a RADIUS (i.e. diameter)
 410  *      packet.  So no server-configuration attributes, or the like.
 411  */
 412 static int vp2diameter(tls_session_t *tls_session, VALUE_PAIR *first)
 413 {
 414         /*
 415          *      RADIUS packets are no more than 4k in size, so if
 416          *      we've got more than 4k of data to write, it's very
 417          *      bad.
 418          */
 419         uint8_t         buffer[4096];
 420         uint8_t         *p;
 421         uint32_t        attr;
 422         uint32_t        length;
 423         uint32_t        vendor;
 424         size_t          total;
 425         VALUE_PAIR      *vp;
 426
 427         p = buffer;
 428         total = 0;
 429
 430         for (vp = first; vp != NULL; vp = vp->next) {
 431                 /*
 432                  *      Too much data: die.
 433                  */
 434                 if ((total + vp->length + 12) >= sizeof(buffer)) {
 435                         DEBUG2("  TTLS output buffer is full!");
 436                         return 0;
 437                 }
 438
 439                 /*
 440                  *      Hmm... we don't group multiple EAP-Messages
 441                  *      together.  Maybe we should...
 442                  */
 443
 444                 /*
 445                  *      Length is no more than 253, due to RADIUS
 446                  *      issues.
 447                  */
 448                 length = vp->length;
 449                 vendor = (vp->attribute >> 16) & 0xffff;
 450                 if (vendor != 0) {
 451                         attr = vp->attribute & 0xffff;
 452                         length |= (1 << 31);
 453                 } else {
 454                         attr = vp->attribute;
 455                 }
 456
 457                 /*
 458                  *      Hmm... set the M bit for all attributes?
 459                  */
 460                 length |= (1 << 30);
 461
 462                 attr = ntohl(attr);
 463
 464                 memcpy(p, &attr, sizeof(attr));
 465                 p += 4;
 466                 total += 4;
 467
 468                 length += 8;    /* includes 8 bytes of attr & length */
 469
 470                 if (vendor != 0) {
 471                         length += 4; /* include 4 bytes of vendor */
 472
 473                         length = ntohl(length);
 474                         memcpy(p, &length, sizeof(length));
 475                         p += 4;
 476                         total += 4;
 477
 478                         vendor = ntohl(vendor);
 479                         memcpy(p, &vendor, sizeof(vendor));
 480                         p += 4;
 481                         total += 4;
 482                 } else {
 483                         length = ntohl(length);
 484                         memcpy(p, &length, sizeof(length));
 485                         p += 4;
 486                         total += 4;
 487                 }
 488
 489                 switch (vp->type) {
 490                 case PW_TYPE_INTEGER:
 491                 case PW_TYPE_DATE:
 492                         attr = ntohl(vp->lvalue); /* stored in host order */
 493                         memcpy(p, &attr, sizeof(attr));
 494                         length = 4;
 495                         break;
 496
 497                 case PW_TYPE_IPADDR:
 498                         attr = vp->lvalue; /* stored in network order */
 499                         memcpy(p, &attr, sizeof(attr));
 500                         length = 4;
 501                         break;
 502
 503                 case PW_TYPE_STRING:
 504                 case PW_TYPE_OCTETS:
 505                 default:
 506                         memcpy(p, vp->strvalue, vp->length);
 507                         length = vp->length;
 508                         break;
 509                 }
 510
 511                 /*
 512                  *      Skip to the end of the data.
 513                  */
 514                 p += length;
 515                 total += length;
 516
 517                 /*
 518                  *      Align the data to a multiple of 4 bytes.
 519                  */
 520                 if ((total & 0x03) != 0) {
 521                         unsigned int i;
 522
 523                         length = 4 - (total & 0x03);
 524                         for (i = 0; i < length; i++) {
 525                                 *p = '\0';
 526                                 p++;
 527                                 total++;
 528                         }
 529                 }
 530         } /* loop over the VP's to write. */
 531
 532         /*
 533          *      Write the data in the buffer to the SSL session.
 534          */
 535         if (total > 0) {
 536 #ifndef NDEBUG
 537                 unsigned int i;
 538
 539                 if (debug_flag > 2) {
 540                         for (i = 0; i < total; i++) {
 541                                 if ((i & 0x0f) == 0) printf("  TTLS tunnel data out %04x: ", i);
 542
 543                                 printf("%02x ", buffer[i]);
 544
 545                                 if ((i & 0x0f) == 0x0f) printf("\n");
 546                         }
 547                         if ((total & 0x0f) != 0) printf("\n");
 548                 }
 549 #endif
 550
 551                 (tls_session->record_plus)(&tls_session->clean_in, buffer, total);
 552
 553                 /*
 554                  *      FIXME: Check the return code.
 555                  */
 556                 tls_handshake_send(tls_session);
 557         }
 558
 559         /*
 560          *      Everything's OK.
 561          */
 562         return 1;
 563 }
 564
 565 /*
 566  *      Use a reply packet to determine what to do.
 567  */
 568 static int process_reply(EAP_HANDLER *handler, tls_session_t *tls_session,
 569                          REQUEST *request, RADIUS_PACKET *reply)
 570 {
 571         int rcode = RLM_MODULE_REJECT;
 572         VALUE_PAIR *vp;
 573         ttls_tunnel_t *t = tls_session->opaque;
 574
 575         handler = handler;      /* -Wunused */
 576
 577         /*
 578          *      If the response packet was Access-Accept, then
 579          *      we're OK.  If not, die horribly.
 580          *
 581          *      FIXME: Take MS-CHAP2-Success attribute, and
 582          *      tunnel it back to the client, to authenticate
 583          *      ourselves to the client.
 584          *
 585          *      FIXME: If we have an Access-Challenge, then
 586          *      the Reply-Message is tunneled back to the client.
 587          *
 588          *      FIXME: If we have an EAP-Message, then that message
 589          *      must be tunneled back to the client.
 590          *
 591          *      FIXME: If we have an Access-Challenge with a State
 592          *      attribute, then do we tunnel that to the client, or
 593          *      keep track of it ourselves?
 594          *
 595          *      FIXME: EAP-Messages can only start with 'identity',
 596          *      NOT 'eap start', so we should check for that....
 597          */
 598         switch (reply->code) {
 599         case PW_AUTHENTICATION_ACK:
 600                 DEBUG2("  TTLS: Got tunneled Access-Accept");
 601
 602                 rcode = RLM_MODULE_OK;
 603
 604                 /*
 605                  *      MS-CHAP2-Success means that we do NOT return
 606                  *      an Access-Accept, but instead tunnel that
 607                  *      attribute to the client, and keep going with
 608                  *      the TTLS session.  Once the client accepts
 609                  *      our identity, it will respond with an empty
 610                  *      packet, and we will send EAP-Success.
 611                  */
 612                 vp = NULL;
 613                 pairmove2(&vp, &reply->vps, PW_MSCHAP2_SUCCESS);
 614                 if (vp) {
 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
 619                         /*
 620                          *      Delete MPPE keys & encryption policy.  We don't
 621                          *      want these here.
 622                          */
 623                         pairdelete(&reply->vps, ((311 << 16) | 7));
 624                         pairdelete(&reply->vps, ((311 << 16) | 8));
 625                         pairdelete(&reply->vps, ((311 << 16) | 16));
 626                         pairdelete(&reply->vps, ((311 << 16) | 17));
 627
 628                         /*
 629                          *      Use the tunneled reply, but not now.
 630                          */
 631                         if (t->use_tunneled_reply) {
 632                                 t->reply = reply->vps;
 633                                 reply->vps = NULL;
 634                         }
 635
 636                 } else { /* no MS-CHAP2-Success */
 637                         /*
 638                          *      Can only have EAP-Message if there's
 639                          *      no MS-CHAP2-Success.  (FIXME: EAP-MSCHAP?)
 640                          *
 641                          *      We also do NOT tunnel the EAP-Success
 642                          *      attribute back to the client, as the client
 643                          *      can figure it out, from the non-tunneled
 644                          *      EAP-Success packet.
 645                          */
 646                         pairmove2(&vp, &reply->vps, PW_EAP_MESSAGE);
 647                         pairfree(&vp);
 648                 }
 649
 650                 /*
 651                  *      Handle the ACK, by tunneling any necessary reply
 652                  *      VP's back to the client.
 653                  */
 654                 if (vp) {
 655                         vp2diameter(tls_session, vp);
 656                         pairfree(&vp);
 657                 }
 658
 659                 /*
 660                  *      If we've been told to use the attributes from
 661                  *      the reply, then do so.
 662                  *
 663                  *      WARNING: This may leak information about the
 664                  *      tunneled user!
 665                  */
 666                 if (t->use_tunneled_reply) {
 667                         pairdelete(&reply->vps, PW_PROXY_STATE);
 668                         pairadd(&request->reply->vps, reply->vps);
 669                         reply->vps = NULL;
 670                 }
 671                 break;
 672
 673
 674         case PW_AUTHENTICATION_REJECT:
 675                 DEBUG2("  TTLS: Got tunneled Access-Reject");
 676                 rcode = RLM_MODULE_REJECT;
 677                 break;
 678
 679                 /*
 680                  *      Handle Access-Challenge, but only if we
 681                  *      send tunneled reply data.  This is because
 682                  *      an Access-Challenge means that we MUST tunnel
 683                  *      a Reply-Message to the client.
 684                  */
 685         case PW_ACCESS_CHALLENGE:
 686                 DEBUG2("  TTLS: Got tunneled Access-Challenge");
 687
 688                 /*
 689                  *      Keep the State attribute, if necessary.
 690                  *
 691                  *      Get rid of the old State, too.
 692                  */
 693                 pairfree(&t->state);
 694                 pairmove2(&t->state, &reply->vps, PW_STATE);
 695
 696                 /*
 697                  *      We should really be a bit smarter about this,
 698                  *      and move over only those attributes which
 699                  *      are relevant to the authentication request,
 700                  *      but that's a lot more work, and this "dumb"
 701                  *      method works in 99.9% of the situations.
 702                  */
 703                 vp = NULL;
 704                 pairmove2(&vp, &reply->vps, PW_EAP_MESSAGE);
 705
 706                 /*
 707                  *      There MUST be a Reply-Message in the challenge,
 708                  *      which we tunnel back to the client.
 709                  *
 710                  *      If there isn't one in the reply VP's, then
 711                  *      we MUST create one, with an empty string as
 712                  *      it's value.
 713                  */
 714                 pairmove2(&vp, &reply->vps, PW_REPLY_MESSAGE);
 715
 716                 /*
 717                  *      Handle the ACK, by tunneling any necessary reply
 718                  *      VP's back to the client.
 719                  */
 720                 if (vp) {
 721                         vp2diameter(tls_session, vp);
 722                         pairfree(&vp);
 723                 }
 724                 rcode = RLM_MODULE_HANDLED;
 725                 break;
 726
 727         default:
 728                 DEBUG2("  TTLS: Unknown RADIUS packet type %d: rejecting tunneled user", reply->code);
 729                 rcode = RLM_MODULE_INVALID;
 730                 break;
 731         }
 732
 733         return rcode;
 734 }
 735
 736
 737 /*
 738  *      Do post-proxy processing,
 739  */
 740 static int eapttls_postproxy(EAP_HANDLER *handler, void *data)
 741 {
 742         int rcode;
 743         tls_session_t *tls_session = (tls_session_t *) data;
 744         REQUEST *fake;
 745
 746         DEBUG2("  TTLS: Passing reply from proxy back into the tunnel.");
 747
 748         /*
 749          *      If there was a fake request associated with the proxied
 750          *      request, do more processing of it.
 751          */
 752         fake = (REQUEST *) request_data_get(handler->request,
 753                                             handler->request->proxy,
 754                                             REQUEST_DATA_EAP_MSCHAP_TUNNEL_CALLBACK);
 755
 756         /*
 757          *      Do the callback, if it exists, and if it was a success.
 758          */
 759         if (fake && (handler->request->proxy_reply->code == PW_AUTHENTICATION_ACK)) {
 760                 VALUE_PAIR *vp;
 761                 REQUEST *request = handler->request;
 762
 763                 /*
 764                  *      Terrible hacks.
 765                  */
 766                 rad_assert(fake->packet == NULL);
 767                 fake->packet = request->proxy;
 768                 request->proxy = NULL;
 769
 770                 rad_assert(fake->reply == NULL);
 771                 fake->reply = request->proxy_reply;
 772                 request->proxy_reply = NULL;
 773
 774                 /*
 775                  *      Perform a post-auth stage for the tunneled
 776                  *      session.
 777                  */
 778                 fake->options &= ~RAD_REQUEST_OPTION_PROXY_EAP;
 779                 rcode = rad_postauth(fake);
 780                 DEBUG2("  POST-AUTH %d", rcode);
 781
 782 #ifndef NDEBUG
 783                 if (debug_flag > 0) {
 784                         printf("  TTLS: Final reply from tunneled session code %d\n",
 785                                fake->reply->code);
 786
 787                         for (vp = fake->reply->vps; vp != NULL; vp = vp->next) {
 788                                 putchar('\t');vp_print(stdout, vp);putchar('\n');
 789                         }
 790                 }
 791 #endif
 792
 793                 /*
 794                  *      Terrible hacks.
 795                  */
 796                 request->proxy = fake->packet;
 797                 fake->packet = NULL;
 798                 request->proxy_reply = fake->reply;
 799                 fake->reply = NULL;
 800
 801                 /*
 802                  *      And we're done with this request.
 803                  */
 804
 805                 switch (rcode) {
 806                 case RLM_MODULE_FAIL:
 807                         request_free(&fake);
 808                         eaptls_fail(handler->eap_ds, 0);
 809                         return 0;
 810                         break;
 811
 812                 default:  /* Don't Do Anything */
 813                         DEBUG2(" TTLS: Got reply %d",
 814                                request->proxy_reply->code);
 815                         break;
 816                 }
 817         }
 818         request_free(&fake);    /* robust if fake == NULL */
 819
 820         /*
 821          *      Process the reply from the home server.
 822          */
 823         rcode = process_reply(handler, tls_session, handler->request,
 824                               handler->request->proxy_reply);
 825
 826         /*
 827          *      The proxy code uses the reply from the home server as
 828          *      the basis for the reply to the NAS.  We don't want that,
 829          *      so we toss it, after we've had our way with it.
 830          */
 831         pairfree(&handler->request->proxy_reply->vps);
 832
 833         switch (rcode) {
 834         case RLM_MODULE_REJECT:
 835                 DEBUG2("  TTLS: Reply was rejected");
 836                 break;
 837
 838         case RLM_MODULE_HANDLED:
 839                 DEBUG2("  TTLS: Reply was handled");
 840                 eaptls_request(handler->eap_ds, tls_session);
 841                 return 1;
 842
 843         case RLM_MODULE_OK:
 844                 DEBUG2("  TTLS: Reply was OK");
 845                 eaptls_success(handler->eap_ds, 0);
 846                 eaptls_gen_mppe_keys(&handler->request->reply->vps,
 847                                      tls_session->ssl,
 848                                      "ttls keying material");
 849                 return 1;
 850
 851         default:
 852                 DEBUG2("  TTLS: Reply was unknown.");
 853                 break;
 854         }
 855
 856         eaptls_fail(handler->eap_ds, 0);
 857         return 0;
 858 }
 859
 860
 861 /*
 862  *      Free a request.
 863  */
 864 static void my_request_free(void *data)
 865 {
 866         REQUEST *request = (REQUEST *)data;
 867
 868         request_free(&request);
 869 }
 870
 871
 872 /*
 873  *      Process the "diameter" contents of the tunneled data.
 874  */
 875 int eapttls_process(EAP_HANDLER *handler, tls_session_t *tls_session)
 876 {
 877         int err;
 878         int rcode = PW_AUTHENTICATION_REJECT;
 879         REQUEST *fake;
 880         VALUE_PAIR *vp;
 881         ttls_tunnel_t *t;
 882         const uint8_t *data;
 883         unsigned int data_len;
 884         char buffer[1024];
 885         REQUEST *request = handler->request;
 886
 887         /*
 888          *      Grab the dirty data, and copy it to our buffer.
 889          *
 890          *      I *really* don't like these 'record_t' things...
 891          */
 892         data_len = (tls_session->record_minus)(&tls_session->dirty_in, buffer, sizeof(buffer));
 893         data = buffer;
 894
 895         /*
 896          *      Write the data from the dirty buffer (i.e. packet
 897          *      data) into the buffer which we will give to SSL for
 898          *      decoding.
 899          *
 900          *      Some of this code COULD technically go into the TLS
 901          *      module, in eaptls_process(), where it returns EAPTLS_OK.
 902          *
 903          *      Similarly, the writing of data to the SSL context could
 904          *      go there, too...
 905          */
 906         BIO_write(tls_session->into_ssl, buffer, data_len);
 907         (tls_session->record_init)(&tls_session->clean_out);
 908
 909         /*
 910          *      Read (and decrypt) the tunneled data from the SSL session,
 911          *      and put it into the decrypted data buffer.
 912          */
 913         err = SSL_read(tls_session->ssl, tls_session->clean_out.data,
 914                        sizeof(tls_session->clean_out.data));
 915         if (err < 0) {
 916                 /*
 917                  *      FIXME: Call SSL_get_error() to see what went
 918                  *      wrong.
 919                  */
 920                 radlog(L_INFO, "rlm_eap_ttls: SSL_read Error");
 921                 return PW_AUTHENTICATION_REJECT;
 922         }
 923
 924         t = (ttls_tunnel_t *) tls_session->opaque;
 925
 926         /*
 927          *      If there's no data, maybe this is an ACK to an
 928          *      MS-CHAP2-Success.
 929          */
 930         if (err == 0) {
 931                 if (t->authenticated) {
 932                         DEBUG2("  TTLS: Got ACK, and the user was already authenticated.");
 933                         return PW_AUTHENTICATION_ACK;
 934                 } /* else no session, no data, die. */
 935
 936                 /*
 937                  *      FIXME: Call SSL_get_error() to see what went
 938                  *      wrong.
 939                  */
 940                 radlog(L_INFO, "rlm_eap_ttls: SSL_read Error");
 941                 return PW_AUTHENTICATION_REJECT;
 942         }
 943
 944         data_len = tls_session->clean_out.used = err;
 945         data = tls_session->clean_out.data;
 946
 947 #ifndef NDEBUG
 948         if (debug_flag > 2) {
 949                 unsigned int i;
 950
 951                 for (i = 0; i < data_len; i++) {
 952                         if ((i & 0x0f) == 0) printf("  TTLS tunnel data in %04x: ", i);
 953
 954                         printf("%02x ", data[i]);
 955
 956                         if ((i & 0x0f) == 0x0f) printf("\n");
 957                 }
 958                 if ((data_len & 0x0f) != 0) printf("\n");
 959         }
 960 #endif
 961
 962         if (!diameter_verify(data, data_len)) {
 963                 return PW_AUTHENTICATION_REJECT;
 964         }
 965
 966         /*
 967          *      Allocate a fake REQUEST structe.
 968          */
 969         fake = request_alloc_fake(request);
 970
 971         rad_assert(fake->packet->vps == NULL);
 972
 973         /*
 974          *      Add the tunneled attributes to the fake request.
 975          */
 976         fake->packet->vps = diameter2vp(tls_session->ssl, data, data_len);
 977         if (!fake->packet->vps) {
 978                 return PW_AUTHENTICATION_REJECT;
 979         }
 980
 981         /*
 982          *      Tell the request that it's a fake one.
 983          */
 984         vp = pairmake("Freeradius-Proxied-To", "127.0.0.1", T_OP_EQ);
 985         if (vp) {
 986                 pairadd(&fake->packet->vps, vp);
 987         }
 988
 989 #ifndef NDEBUG
 990         if (debug_flag > 0) {
 991                 printf("  TTLS: Got tunneled request\n");
 992
 993                 for (vp = fake->packet->vps; vp != NULL; vp = vp->next) {
 994                         putchar('\t');vp_print(stdout, vp);putchar('\n');
 995                 }
 996         }
 997 #endif
 998
 999         /*
1000          *      Update other items in the REQUEST data structure.
1001          */
1002         fake->username = pairfind(fake->packet->vps, PW_USER_NAME);
1003         fake->password = pairfind(fake->packet->vps, PW_PASSWORD);
1004
1005         /*
1006          *      No User-Name, try to create one from stored data.
1007          */
1008         if (!fake->username) {
1009                 /*
1010                  *      No User-Name in the stored data, look for
1011                  *      an EAP-Identity, and pull it out of there.
1012                  */
1013                 if (!t->username) {
1014                         vp = pairfind(fake->packet->vps, PW_EAP_MESSAGE);
1015                         if (vp &&
1016                             (vp->length >= EAP_HEADER_LEN + 2) &&
1017                             (vp->strvalue[0] == PW_EAP_RESPONSE) &&
1018                             (vp->strvalue[EAP_HEADER_LEN] == PW_EAP_IDENTITY) &&
1019                             (vp->strvalue[EAP_HEADER_LEN + 1] != 0)) {
1020                                 /*
1021                                  *      Create & remember a User-Name
1022                                  */
1023                                 t->username = pairmake("User-Name", "", T_OP_EQ);
1024                                 rad_assert(t->username != NULL);
1025
1026                                 memcpy(t->username->strvalue, vp->strvalue + 5,
1027                                        vp->length - 5);
1028                                 t->username->length = vp->length - 5;
1029                                 t->username->strvalue[t->username->length] = 0;
1030
1031                                 DEBUG2("  TTLS: Got tunneled identity of %s",
1032                                        t->username->strvalue);
1033
1034                                 /*
1035                                  *      If there's a default EAP type,
1036                                  *      set it here.
1037                                  */
1038                                 if (t->default_eap_type != 0) {
1039                                         DEBUG2("  TTLS: Setting default EAP type for tunneled EAP session.");
1040                                         vp = paircreate(PW_EAP_TYPE,
1041                                                         PW_TYPE_INTEGER);
1042                                         rad_assert(vp != NULL);
1043                                         vp->lvalue = t->default_eap_type;
1044                                         pairadd(&fake->config_items, vp);
1045                                 }
1046
1047                         } else {
1048                                 /*
1049                                  *      Don't reject the request outright,
1050                                  *      as it's permitted to do EAP without
1051                                  *      user-name.
1052                                  */
1053                                 DEBUG2("  rlm_eap_ttls: WARNING! No EAP-Identity found to start EAP conversation.");
1054                         }
1055                 } /* else there WAS a t->username */
1056
1057                 if (t->username) {
1058                         vp = paircopy(t->username);
1059                         pairadd(&fake->packet->vps, vp);
1060                         fake->username = pairfind(fake->packet->vps, PW_USER_NAME);
1061                 }
1062         } /* else the request ALREADY had a User-Name */
1063
1064         /*
1065          *      Add the State attribute, too, if it exists.
1066          */
1067         if (t->state) {
1068                 DEBUG2("  TTLS: Adding old state with %02x %02x",
1069                        t->state->strvalue[0], t->state->strvalue[1]);
1070                 vp = paircopy(t->state);
1071                 if (vp) pairadd(&fake->packet->vps, vp);
1072         }
1073
1074         /*
1075          *      If this is set, we copy SOME of the request attributes
1076          *      from outside of the tunnel to inside of the tunnel.
1077          *
1078          *      We copy ONLY those attributes which do NOT already
1079          *      exist in the tunneled request.
1080          */
1081         if (t->copy_request_to_tunnel) {
1082                 VALUE_PAIR *copy;
1083
1084                 for (vp = request->packet->vps; vp != NULL; vp = vp->next) {
1085                         /*
1086                          *      The attribute is a server-side thingy,
1087                          *      don't copy it.
1088                          */
1089                         if ((vp->attribute > 255) &&
1090                             (((vp->attribute >> 16) & 0xffff) == 0)) {
1091                                 continue;
1092                         }
1093
1094                         /*
1095                          *      The outside attribute is already in the
1096                          *      tunnel, don't copy it.
1097                          *
1098                          *      This works for BOTH attributes which
1099                          *      are originally in the tunneled request,
1100                          *      AND attributes which are copied there
1101                          *      from below.
1102                          */
1103                         if (pairfind(fake->packet->vps, vp->attribute)) {
1104                                 continue;
1105                         }
1106
1107                         /*
1108                          *      Some attributes are handled specially.
1109                          */
1110                         switch (vp->attribute) {
1111                                 /*
1112                                  *      NEVER copy Message-Authenticator,
1113                                  *      EAP-Message, or State.  They're
1114                                  *      only for outside of the tunnel.
1115                                  */
1116                         case PW_USER_NAME:
1117                         case PW_USER_PASSWORD:
1118                         case PW_CHAP_PASSWORD:
1119                         case PW_CHAP_CHALLENGE:
1120                         case PW_PROXY_STATE:
1121                         case PW_MESSAGE_AUTHENTICATOR:
1122                         case PW_EAP_MESSAGE:
1123                         case PW_STATE:
1124                                 continue;
1125                                 break;
1126
1127                                 /*
1128                                  *      By default, copy it over.
1129                                  */
1130                         default:
1131                                 break;
1132                         }
1133
1134                         /*
1135                          *      Don't copy from the head, we've already
1136                          *      checked it.
1137                          */
1138                         copy = paircopy2(vp, vp->attribute);
1139                         pairadd(&fake->packet->vps, copy);
1140                 }
1141         }
1142
1143 #ifndef NDEBUG
1144         if (debug_flag > 0) {
1145           printf("  TTLS: Sending tunneled request\n");
1146
1147           for (vp = fake->packet->vps; vp != NULL; vp = vp->next) {
1148             putchar('\t');vp_print(stdout, vp);putchar('\n');
1149           }
1150         }
1151 #endif
1152
1153         /*
1154          *      Call authentication recursively, which will
1155          *      do PAP, CHAP, MS-CHAP, etc.
1156          */
1157         rad_authenticate(fake);
1158
1159         /*
1160          *      Note that we don't do *anything* with the reply
1161          *      attributes.
1162          */
1163 #ifndef NDEBUG
1164         if (debug_flag > 0) {
1165           printf("  TTLS: Got tunneled reply RADIUS code %d\n",
1166                  fake->reply->code);
1167
1168           for (vp = fake->reply->vps; vp != NULL; vp = vp->next) {
1169             putchar('\t');vp_print(stdout, vp);putchar('\n');
1170           }
1171         }
1172 #endif
1173
1174         /*
1175          *      Decide what to do with the reply.
1176          */
1177         switch (fake->reply->code) {
1178         case 0:                 /* No reply code, must be proxied... */
1179                 vp = pairfind(fake->config_items, PW_PROXY_TO_REALM);
1180                 if (vp) {
1181                         eap_tunnel_data_t *tunnel;
1182                         DEBUG2("  TTLS: Tunneled authentication will be proxied to %s", vp->strvalue);
1183
1184                         /*
1185                          *      Tell the original request that it's going
1186                          *      to be proxied.
1187                          */
1188                         pairmove2(&(request->config_items),
1189                                   &(fake->config_items),
1190                                   PW_PROXY_TO_REALM);
1191
1192                         /*
1193                          *      Seed the proxy packet with the
1194                          *      tunneled request.
1195                          */
1196                         rad_assert(request->proxy == NULL);
1197                         request->proxy = fake->packet;
1198                         fake->packet = NULL;
1199                         rad_free(&fake->reply);
1200                         fake->reply = NULL;
1201
1202                         /*
1203                          *      Set up the callbacks for the tunnel
1204                          */
1205                         tunnel = rad_malloc(sizeof(*tunnel));
1206                         memset(tunnel, 0, sizeof(*tunnel));
1207
1208                         tunnel->tls_session = tls_session;
1209                         tunnel->callback = eapttls_postproxy;
1210
1211                         /*
1212                          *      Associate the callback with the request.
1213                          */
1214                         rcode = request_data_add(request,
1215                                                  request->proxy,
1216                                                  REQUEST_DATA_EAP_TUNNEL_CALLBACK,
1217                                                  tunnel, free);
1218                         rad_assert(rcode == 0);
1219
1220                         /*
1221                          *      rlm_eap.c has taken care of associating
1222                          *      the handler with the fake request.
1223                          *
1224                          *      So we associate the fake request with
1225                          *      this request.
1226                          */
1227                         rcode = request_data_add(request,
1228                                                  request->proxy,
1229                                                  REQUEST_DATA_EAP_MSCHAP_TUNNEL_CALLBACK,
1230                                                  fake, my_request_free);
1231                         rad_assert(rcode == 0);
1232                         fake = NULL;
1233
1234                         /*
1235                          *      Didn't authenticate the packet, but
1236                          *      we're proxying it.
1237                          */
1238                         rcode = PW_STATUS_CLIENT;
1239
1240                 } else {
1241                         DEBUG2("  TTLS: No tunneled reply was found for request %d , and the request was not proxied: rejecting the user.",
1242                                request->number);
1243                         rcode = PW_AUTHENTICATION_REJECT;
1244                 }
1245                 break;
1246
1247         default:
1248                 /*
1249                  *      Returns RLM_MODULE_FOO, and we want to return
1250                  *      PW_FOO
1251                  */
1252                 rcode = process_reply(handler, tls_session, request,
1253                                       fake->reply);
1254                 switch (rcode) {
1255                 case RLM_MODULE_REJECT:
1256                         rcode = PW_AUTHENTICATION_REJECT;
1257                         break;
1258
1259                 case RLM_MODULE_HANDLED:
1260                         rcode = PW_ACCESS_CHALLENGE;
1261                         break;
1262
1263                 case RLM_MODULE_OK:
1264                         rcode = PW_AUTHENTICATION_ACK;
1265                         break;
1266
1267                 default:
1268                         rcode = PW_AUTHENTICATION_REJECT;
1269                         break;
1270                 }
1271                 break;
1272         }
1273
1274         request_free(&fake);
1275
1276         return rcode;
1277 }