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                                 uint8_t challenge[16];
 354
 355                                 eapttls_gen_challenge(ssl, challenge,
 356                                                       sizeof(challenge));
 357
 358                                 if (memcmp(challenge, vp->strvalue,
 359                                            vp->length) != 0) {
 360                                         DEBUG2("  TTLS: Tunneled challenge is incorrect");
 361                                         pairfree(&first);
 362                                         pairfree(&vp);
 363                                         return NULL;
 364                                 }
 365                         }
 366                         break;
 367
 368                 default:
 369                         break;
 370                 } /* switch over checking/re-writing of attributes. */
 371
 372                 /*
 373                  *      Update the list.
 374                  */
 375                 *last = vp;
 376                 last = &(vp->next);
 377
 378                 /*
 379                  *      Catch non-aligned attributes.
 380                  */
 381                 if (data_left == length) break;
 382
 383                 /*
 384                  *      The length does NOT include the padding, so
 385                  *      we've got to account for it here by rounding up
 386                  *      to the nearest 4-byte boundary.
 387                  */
 388                 length += 0x03;
 389                 length &= ~0x03;
 390
 391                 rad_assert(data_left >= length);
 392                 data_left -= length;
 393                 data += length - offset; /* already updated */
 394         }
 395
 396         /*
 397          *      We got this far.  It looks OK.
 398          */
 399         return first;
 400 }
 401
 402 /*
 403  *      Convert VALUE_PAIR's to diameter attributes, and write them
 404  *      to an SSL session.
 405  *
 406  *      The ONLY VALUE_PAIR's which may be passed to this function
 407  *      are ones which can go inside of a RADIUS (i.e. diameter)
 408  *      packet.  So no server-configuration attributes, or the like.
 409  */
 410 static int vp2diameter(tls_session_t *tls_session, VALUE_PAIR *first)
 411 {
 412         /*
 413          *      RADIUS packets are no more than 4k in size, so if
 414          *      we've got more than 4k of data to write, it's very
 415          *      bad.
 416          */
 417         uint8_t         buffer[4096];
 418         uint8_t         *p;
 419         uint32_t        attr;
 420         uint32_t        length;
 421         uint32_t        vendor;
 422         size_t          total;
 423         VALUE_PAIR      *vp;
 424
 425         p = buffer;
 426         total = 0;
 427
 428         for (vp = first; vp != NULL; vp = vp->next) {
 429                 /*
 430                  *      Too much data: die.
 431                  */
 432                 if ((total + vp->length + 12) >= sizeof(buffer)) {
 433                         DEBUG2("  TTLS output buffer is full!");
 434                         return 0;
 435                 }
 436
 437                 /*
 438                  *      Hmm... we don't group multiple EAP-Messages
 439                  *      together.  Maybe we should...
 440                  */
 441
 442                 /*
 443                  *      Length is no more than 253, due to RADIUS
 444                  *      issues.
 445                  */
 446                 length = vp->length;
 447                 vendor = (vp->attribute >> 16) & 0xffff;
 448                 if (vendor != 0) {
 449                         attr = vp->attribute & 0xffff;
 450                         length |= (1 << 31);
 451                 } else {
 452                         attr = vp->attribute;
 453                 }
 454
 455                 /*
 456                  *      Hmm... set the M bit for all attributes?
 457                  */
 458                 length |= (1 << 30);
 459
 460                 attr = ntohl(attr);
 461
 462                 memcpy(p, &attr, sizeof(attr));
 463                 p += 4;
 464                 total += 4;
 465
 466                 length += 8;    /* includes 8 bytes of attr & length */
 467
 468                 if (vendor != 0) {
 469                         length += 4; /* include 4 bytes of vendor */
 470
 471                         length = ntohl(length);
 472                         memcpy(p, &length, sizeof(length));
 473                         p += 4;
 474                         total += 4;
 475
 476                         vendor = ntohl(vendor);
 477                         memcpy(p, &vendor, sizeof(vendor));
 478                         p += 4;
 479                         total += 4;
 480                 } else {
 481                         length = ntohl(length);
 482                         memcpy(p, &length, sizeof(length));
 483                         p += 4;
 484                         total += 4;
 485                 }
 486
 487                 switch (vp->type) {
 488                 case PW_TYPE_INTEGER:
 489                 case PW_TYPE_DATE:
 490                         attr = ntohl(vp->lvalue); /* stored in host order */
 491                         memcpy(p, &attr, sizeof(attr));
 492                         length = 4;
 493                         break;
 494
 495                 case PW_TYPE_IPADDR:
 496                         attr = vp->lvalue; /* stored in network order */
 497                         memcpy(p, &attr, sizeof(attr));
 498                         length = 4;
 499                         break;
 500
 501                 case PW_TYPE_STRING:
 502                 case PW_TYPE_OCTETS:
 503                 default:
 504                         memcpy(p, vp->strvalue, vp->length);
 505                         length = vp->length;
 506                         break;
 507                 }
 508
 509                 /*
 510                  *      Skip to the end of the data.
 511                  */
 512                 p += length;
 513                 total += length;
 514
 515                 /*
 516                  *      Align the data to a multiple of 4 bytes.
 517                  */
 518                 if ((total & 0x03) != 0) {
 519                         unsigned int i;
 520
 521                         length = 4 - (total & 0x03);
 522                         for (i = 0; i < length; i++) {
 523                                 *p = '\0';
 524                                 p++;
 525                                 total++;
 526                         }
 527                 }
 528         } /* loop over the VP's to write. */
 529
 530         /*
 531          *      Write the data in the buffer to the SSL session.
 532          */
 533         if (total > 0) {
 534 #ifndef NDEBUG
 535                 unsigned int i;
 536
 537                 if (debug_flag > 2) {
 538                         for (i = 0; i < total; i++) {
 539                                 if ((i & 0x0f) == 0) printf("  TTLS tunnel data out %04x: ", i);
 540
 541                                 printf("%02x ", buffer[i]);
 542
 543                                 if ((i & 0x0f) == 0x0f) printf("\n");
 544                         }
 545                         if ((total & 0x0f) != 0) printf("\n");
 546                 }
 547 #endif
 548
 549                 (tls_session->record_plus)(&tls_session->clean_in, buffer, total);
 550
 551                 /*
 552                  *      FIXME: Check the return code.
 553                  */
 554                 tls_handshake_send(tls_session);
 555         }
 556
 557         /*
 558          *      Everything's OK.
 559          */
 560         return 1;
 561 }
 562
 563 /*
 564  *      Use a reply packet to determine what to do.
 565  */
 566 static int process_reply(EAP_HANDLER *handler, tls_session_t *tls_session,
 567                          REQUEST *request, RADIUS_PACKET *reply)
 568 {
 569         int rcode = RLM_MODULE_REJECT;
 570         VALUE_PAIR *vp;
 571         ttls_tunnel_t *t = tls_session->opaque;
 572
 573         handler = handler;      /* -Wunused */
 574
 575         /*
 576          *      If the response packet was Access-Accept, then
 577          *      we're OK.  If not, die horribly.
 578          *
 579          *      FIXME: Take MS-CHAP2-Success attribute, and
 580          *      tunnel it back to the client, to authenticate
 581          *      ourselves to the client.
 582          *
 583          *      FIXME: If we have an Access-Challenge, then
 584          *      the Reply-Message is tunneled back to the client.
 585          *
 586          *      FIXME: If we have an EAP-Message, then that message
 587          *      must be tunneled back to the client.
 588          *
 589          *      FIXME: If we have an Access-Challenge with a State
 590          *      attribute, then do we tunnel that to the client, or
 591          *      keep track of it ourselves?
 592          *
 593          *      FIXME: EAP-Messages can only start with 'identity',
 594          *      NOT 'eap start', so we should check for that....
 595          */
 596         switch (reply->code) {
 597         case PW_AUTHENTICATION_ACK:
 598                 DEBUG2("  TTLS: Got tunneled Access-Accept");
 599
 600                 rcode = RLM_MODULE_OK;
 601
 602                 /*
 603                  *      MS-CHAP2-Success means that we do NOT return
 604                  *      an Access-Accept, but instead tunnel that
 605                  *      attribute to the client, and keep going with
 606                  *      the TTLS session.  Once the client accepts
 607                  *      our identity, it will respond with an empty
 608                  *      packet, and we will send EAP-Success.
 609                  */
 610                 vp = NULL;
 611                 pairmove2(&vp, &reply->vps, PW_MSCHAP2_SUCCESS);
 612                 if (vp) {
 613                         DEBUG2("  TTLS: Got MS-CHAP2-Success, tunneling it to the client in a challenge.");
 614                         rcode = RLM_MODULE_HANDLED;
 615                         t->authenticated = TRUE;
 616
 617                         /*
 618                          *      Delete MPPE keys & encryption policy.  We don't
 619                          *      want these here.
 620                          */
 621                         pairdelete(&reply->vps, ((311 << 16) | 7));
 622                         pairdelete(&reply->vps, ((311 << 16) | 8));
 623                         pairdelete(&reply->vps, ((311 << 16) | 16));
 624                         pairdelete(&reply->vps, ((311 << 16) | 17));
 625
 626                         /*
 627                          *      Use the tunneled reply, but not now.
 628                          */
 629                         if (t->use_tunneled_reply) {
 630                                 t->reply = reply->vps;
 631                                 reply->vps = NULL;
 632                         }
 633
 634                 } else { /* no MS-CHAP2-Success */
 635                         /*
 636                          *      Can only have EAP-Message if there's
 637                          *      no MS-CHAP2-Success.  (FIXME: EAP-MSCHAP?)
 638                          *
 639                          *      We also do NOT tunnel the EAP-Success
 640                          *      attribute back to the client, as the client
 641                          *      can figure it out, from the non-tunneled
 642                          *      EAP-Success packet.
 643                          */
 644                         pairmove2(&vp, &reply->vps, PW_EAP_MESSAGE);
 645                         pairfree(&vp);
 646                 }
 647
 648                 /*
 649                  *      Handle the ACK, by tunneling any necessary reply
 650                  *      VP's back to the client.
 651                  */
 652                 if (vp) {
 653                         vp2diameter(tls_session, vp);
 654                         pairfree(&vp);
 655                 }
 656
 657                 /*
 658                  *      If we've been told to use the attributes from
 659                  *      the reply, then do so.
 660                  *
 661                  *      WARNING: This may leak information about the
 662                  *      tunneled user!
 663                  */
 664                 if (t->use_tunneled_reply) {
 665                         pairdelete(&reply->vps, PW_PROXY_STATE);
 666                         pairadd(&request->reply->vps, reply->vps);
 667                         reply->vps = NULL;
 668                 }
 669                 break;
 670
 671
 672         case PW_AUTHENTICATION_REJECT:
 673                 DEBUG2("  TTLS: Got tunneled Access-Reject");
 674                 rcode = RLM_MODULE_REJECT;
 675                 break;
 676
 677                 /*
 678                  *      Handle Access-Challenge, but only if we
 679                  *      send tunneled reply data.  This is because
 680                  *      an Access-Challenge means that we MUST tunnel
 681                  *      a Reply-Message to the client.
 682                  */
 683         case PW_ACCESS_CHALLENGE:
 684                 DEBUG2("  TTLS: Got tunneled Access-Challenge");
 685
 686                 /*
 687                  *      Keep the State attribute, if necessary.
 688                  *
 689                  *      Get rid of the old State, too.
 690                  */
 691                 pairfree(&t->state);
 692                 pairmove2(&t->state, &reply->vps, PW_STATE);
 693
 694                 /*
 695                  *      We should really be a bit smarter about this,
 696                  *      and move over only those attributes which
 697                  *      are relevant to the authentication request,
 698                  *      but that's a lot more work, and this "dumb"
 699                  *      method works in 99.9% of the situations.
 700                  */
 701                 vp = NULL;
 702                 pairmove2(&vp, &reply->vps, PW_EAP_MESSAGE);
 703
 704                 /*
 705                  *      There MUST be a Reply-Message in the challenge,
 706                  *      which we tunnel back to the client.
 707                  *
 708                  *      If there isn't one in the reply VP's, then
 709                  *      we MUST create one, with an empty string as
 710                  *      it's value.
 711                  */
 712                 pairmove2(&vp, &reply->vps, PW_REPLY_MESSAGE);
 713
 714                 /*
 715                  *      Handle the ACK, by tunneling any necessary reply
 716                  *      VP's back to the client.
 717                  */
 718                 if (vp) {
 719                         vp2diameter(tls_session, vp);
 720                         pairfree(&vp);
 721                 }
 722                 rcode = RLM_MODULE_HANDLED;
 723                 break;
 724
 725         default:
 726                 DEBUG2("  TTLS: Unknown RADIUS packet type %d: rejecting tunneled user", reply->code);
 727                 rcode = RLM_MODULE_INVALID;
 728                 break;
 729         }
 730
 731         return rcode;
 732 }
 733
 734
 735 /*
 736  *      Do post-proxy processing,
 737  */
 738 static int eapttls_postproxy(EAP_HANDLER *handler, void *data)
 739 {
 740         int rcode;
 741         tls_session_t *tls_session = (tls_session_t *) data;
 742         REQUEST *fake;
 743
 744         DEBUG2("  TTLS: Passing reply from proxy back into the tunnel.");
 745
 746         /*
 747          *      If there was a fake request associated with the proxied
 748          *      request, do more processing of it.
 749          */
 750         fake = (REQUEST *) request_data_get(handler->request,
 751                                             handler->request->proxy,
 752                                             REQUEST_DATA_EAP_MSCHAP_TUNNEL_CALLBACK);
 753
 754         /*
 755          *      Do the callback, if it exists, and if it was a success.
 756          */
 757         if (fake && (handler->request->proxy_reply->code == PW_AUTHENTICATION_ACK)) {
 758                 VALUE_PAIR *vp;
 759                 REQUEST *request = handler->request;
 760
 761                 /*
 762                  *      Terrible hacks.
 763                  */
 764                 rad_assert(fake->packet == NULL);
 765                 fake->packet = request->proxy;
 766                 request->proxy = NULL;
 767
 768                 rad_assert(fake->reply == NULL);
 769                 fake->reply = request->proxy_reply;
 770                 request->proxy_reply = NULL;
 771
 772                 /*
 773                  *      Perform a post-auth stage for the tunneled
 774                  *      session.
 775                  */
 776                 fake->options &= ~RAD_REQUEST_OPTION_PROXY_EAP;
 777                 rcode = rad_postauth(fake);
 778                 DEBUG2("  POST-AUTH %d", rcode);
 779
 780 #ifndef NDEBUG
 781                 if (debug_flag > 0) {
 782                         printf("  TTLS: Final reply from tunneled session code %d\n",
 783                                fake->reply->code);
 784
 785                         for (vp = fake->reply->vps; vp != NULL; vp = vp->next) {
 786                                 putchar('\t');vp_print(stdout, vp);putchar('\n');
 787                         }
 788                 }
 789 #endif
 790
 791                 /*
 792                  *      Terrible hacks.
 793                  */
 794                 request->proxy = fake->packet;
 795                 fake->packet = NULL;
 796                 request->proxy_reply = fake->reply;
 797                 fake->reply = NULL;
 798
 799                 /*
 800                  *      And we're done with this request.
 801                  */
 802
 803                 switch (rcode) {
 804                 case RLM_MODULE_FAIL:
 805                         request_free(&fake);
 806                         eaptls_fail(handler->eap_ds, 0);
 807                         return 0;
 808                         break;
 809
 810                 default:  /* Don't Do Anything */
 811                         DEBUG2(" TTLS: Got reply %d",
 812                                request->proxy_reply->code);
 813                         break;
 814                 }
 815         }
 816         request_free(&fake);    /* robust if fake == NULL */
 817
 818         /*
 819          *      Process the reply from the home server.
 820          */
 821         rcode = process_reply(handler, tls_session, handler->request,
 822                               handler->request->proxy_reply);
 823
 824         /*
 825          *      The proxy code uses the reply from the home server as
 826          *      the basis for the reply to the NAS.  We don't want that,
 827          *      so we toss it, after we've had our way with it.
 828          */
 829         pairfree(&handler->request->proxy_reply->vps);
 830
 831         switch (rcode) {
 832         case RLM_MODULE_REJECT:
 833                 DEBUG2("  TTLS: Reply was rejected");
 834                 break;
 835
 836         case RLM_MODULE_HANDLED:
 837                 DEBUG2("  TTLS: Reply was handled");
 838                 eaptls_request(handler->eap_ds, tls_session);
 839                 return 1;
 840
 841         case RLM_MODULE_OK:
 842                 DEBUG2("  TTLS: Reply was OK");
 843                 eaptls_success(handler->eap_ds, 0);
 844                 eaptls_gen_mppe_keys(&handler->request->reply->vps,
 845                                      tls_session->ssl,
 846                                      "ttls keying material");
 847                 return 1;
 848
 849         default:
 850                 DEBUG2("  TTLS: Reply was unknown.");
 851                 break;
 852         }
 853
 854         eaptls_fail(handler->eap_ds, 0);
 855         return 0;
 856 }
 857
 858
 859 /*
 860  *      Free a request.
 861  */
 862 static void my_request_free(void *data)
 863 {
 864         REQUEST *request = (REQUEST *)data;
 865
 866         request_free(&request);
 867 }
 868
 869
 870 /*
 871  *      Process the "diameter" contents of the tunneled data.
 872  */
 873 int eapttls_process(EAP_HANDLER *handler, tls_session_t *tls_session)
 874 {
 875         int err;
 876         int rcode = PW_AUTHENTICATION_REJECT;
 877         REQUEST *fake;
 878         VALUE_PAIR *vp;
 879         ttls_tunnel_t *t;
 880         const uint8_t *data;
 881         unsigned int data_len;
 882         char buffer[1024];
 883         REQUEST *request = handler->request;
 884
 885         /*
 886          *      Grab the dirty data, and copy it to our buffer.
 887          *
 888          *      I *really* don't like these 'record_t' things...
 889          */
 890         data_len = (tls_session->record_minus)(&tls_session->dirty_in, buffer, sizeof(buffer));
 891         data = buffer;
 892
 893         /*
 894          *      Write the data from the dirty buffer (i.e. packet
 895          *      data) into the buffer which we will give to SSL for
 896          *      decoding.
 897          *
 898          *      Some of this code COULD technically go into the TLS
 899          *      module, in eaptls_process(), where it returns EAPTLS_OK.
 900          *
 901          *      Similarly, the writing of data to the SSL context could
 902          *      go there, too...
 903          */
 904         BIO_write(tls_session->into_ssl, buffer, data_len);
 905         (tls_session->record_init)(&tls_session->clean_out);
 906
 907         /*
 908          *      Read (and decrypt) the tunneled data from the SSL session,
 909          *      and put it into the decrypted data buffer.
 910          */
 911         err = SSL_read(tls_session->ssl, tls_session->clean_out.data,
 912                        sizeof(tls_session->clean_out.data));
 913         if (err < 0) {
 914                 /*
 915                  *      FIXME: Call SSL_get_error() to see what went
 916                  *      wrong.
 917                  */
 918                 radlog(L_INFO, "rlm_eap_ttls: SSL_read Error");
 919                 return PW_AUTHENTICATION_REJECT;
 920         }
 921
 922         t = (ttls_tunnel_t *) tls_session->opaque;
 923
 924         /*
 925          *      If there's no data, maybe this is an ACK to an
 926          *      MS-CHAP2-Success.
 927          */
 928         if (err == 0) {
 929                 if (t->authenticated) {
 930                         DEBUG2("  TTLS: Got ACK, and the user was already authenticated.");
 931                         return PW_AUTHENTICATION_ACK;
 932                 } /* else no session, no data, die. */
 933
 934                 /*
 935                  *      FIXME: Call SSL_get_error() to see what went
 936                  *      wrong.
 937                  */
 938                 radlog(L_INFO, "rlm_eap_ttls: SSL_read Error");
 939                 return PW_AUTHENTICATION_REJECT;
 940         }
 941
 942         data_len = tls_session->clean_out.used = err;
 943         data = tls_session->clean_out.data;
 944
 945 #ifndef NDEBUG
 946         if (debug_flag > 2) {
 947                 unsigned int i;
 948
 949                 for (i = 0; i < data_len; i++) {
 950                         if ((i & 0x0f) == 0) printf("  TTLS tunnel data in %04x: ", i);
 951
 952                         printf("%02x ", data[i]);
 953
 954                         if ((i & 0x0f) == 0x0f) printf("\n");
 955                 }
 956                 if ((data_len & 0x0f) != 0) printf("\n");
 957         }
 958 #endif
 959
 960         if (!diameter_verify(data, data_len)) {
 961                 return PW_AUTHENTICATION_REJECT;
 962         }
 963
 964         /*
 965          *      Allocate a fake REQUEST structe.
 966          */
 967         fake = request_alloc_fake(request);
 968
 969         rad_assert(fake->packet->vps == NULL);
 970
 971         /*
 972          *      Add the tunneled attributes to the fake request.
 973          */
 974         fake->packet->vps = diameter2vp(tls_session->ssl, data, data_len);
 975         if (!fake->packet->vps) {
 976                 request_free(&fake);
 977                 return PW_AUTHENTICATION_REJECT;
 978         }
 979
 980         /*
 981          *      Tell the request that it's a fake one.
 982          */
 983         vp = pairmake("Freeradius-Proxied-To", "127.0.0.1", T_OP_EQ);
 984         if (vp) {
 985                 pairadd(&fake->packet->vps, vp);
 986         }
 987
 988 #ifndef NDEBUG
 989         if (debug_flag > 0) {
 990                 printf("  TTLS: Got tunneled request\n");
 991
 992                 for (vp = fake->packet->vps; vp != NULL; vp = vp->next) {
 993                         putchar('\t');vp_print(stdout, vp);putchar('\n');
 994                 }
 995         }
 996 #endif
 997
 998         /*
 999          *      Update other items in the REQUEST data structure.
1000          */
1001         fake->username = pairfind(fake->packet->vps, PW_USER_NAME);
1002         fake->password = pairfind(fake->packet->vps, PW_PASSWORD);
1003
1004         /*
1005          *      No User-Name, try to create one from stored data.
1006          */
1007         if (!fake->username) {
1008                 /*
1009                  *      No User-Name in the stored data, look for
1010                  *      an EAP-Identity, and pull it out of there.
1011                  */
1012                 if (!t->username) {
1013                         vp = pairfind(fake->packet->vps, PW_EAP_MESSAGE);
1014                         if (vp &&
1015                             (vp->length >= EAP_HEADER_LEN + 2) &&
1016                             (vp->strvalue[0] == PW_EAP_RESPONSE) &&
1017                             (vp->strvalue[EAP_HEADER_LEN] == PW_EAP_IDENTITY) &&
1018                             (vp->strvalue[EAP_HEADER_LEN + 1] != 0)) {
1019                                 /*
1020                                  *      Create & remember a User-Name
1021                                  */
1022                                 t->username = pairmake("User-Name", "", T_OP_EQ);
1023                                 rad_assert(t->username != NULL);
1024
1025                                 memcpy(t->username->strvalue, vp->strvalue + 5,
1026                                        vp->length - 5);
1027                                 t->username->length = vp->length - 5;
1028                                 t->username->strvalue[t->username->length] = 0;
1029
1030                                 DEBUG2("  TTLS: Got tunneled identity of %s",
1031                                        t->username->strvalue);
1032
1033                                 /*
1034                                  *      If there's a default EAP type,
1035                                  *      set it here.
1036                                  */
1037                                 if (t->default_eap_type != 0) {
1038                                         DEBUG2("  TTLS: Setting default EAP type for tunneled EAP session.");
1039                                         vp = paircreate(PW_EAP_TYPE,
1040                                                         PW_TYPE_INTEGER);
1041                                         rad_assert(vp != NULL);
1042                                         vp->lvalue = t->default_eap_type;
1043                                         pairadd(&fake->config_items, vp);
1044                                 }
1045
1046                         } else {
1047                                 /*
1048                                  *      Don't reject the request outright,
1049                                  *      as it's permitted to do EAP without
1050                                  *      user-name.
1051                                  */
1052                                 DEBUG2("  rlm_eap_ttls: WARNING! No EAP-Identity found to start EAP conversation.");
1053                         }
1054                 } /* else there WAS a t->username */
1055
1056                 if (t->username) {
1057                         vp = paircopy(t->username);
1058                         pairadd(&fake->packet->vps, vp);
1059                         fake->username = pairfind(fake->packet->vps, PW_USER_NAME);
1060                 }
1061         } /* else the request ALREADY had a User-Name */
1062
1063         /*
1064          *      Add the State attribute, too, if it exists.
1065          */
1066         if (t->state) {
1067                 DEBUG2("  TTLS: Adding old state with %02x %02x",
1068                        t->state->strvalue[0], t->state->strvalue[1]);
1069                 vp = paircopy(t->state);
1070                 if (vp) pairadd(&fake->packet->vps, vp);
1071         }
1072
1073         /*
1074          *      If this is set, we copy SOME of the request attributes
1075          *      from outside of the tunnel to inside of the tunnel.
1076          *
1077          *      We copy ONLY those attributes which do NOT already
1078          *      exist in the tunneled request.
1079          */
1080         if (t->copy_request_to_tunnel) {
1081                 VALUE_PAIR *copy;
1082
1083                 for (vp = request->packet->vps; vp != NULL; vp = vp->next) {
1084                         /*
1085                          *      The attribute is a server-side thingy,
1086                          *      don't copy it.
1087                          */
1088                         if ((vp->attribute > 255) &&
1089                             (((vp->attribute >> 16) & 0xffff) == 0)) {
1090                                 continue;
1091                         }
1092
1093                         /*
1094                          *      The outside attribute is already in the
1095                          *      tunnel, don't copy it.
1096                          *
1097                          *      This works for BOTH attributes which
1098                          *      are originally in the tunneled request,
1099                          *      AND attributes which are copied there
1100                          *      from below.
1101                          */
1102                         if (pairfind(fake->packet->vps, vp->attribute)) {
1103                                 continue;
1104                         }
1105
1106                         /*
1107                          *      Some attributes are handled specially.
1108                          */
1109                         switch (vp->attribute) {
1110                                 /*
1111                                  *      NEVER copy Message-Authenticator,
1112                                  *      EAP-Message, or State.  They're
1113                                  *      only for outside of the tunnel.
1114                                  */
1115                         case PW_USER_NAME:
1116                         case PW_USER_PASSWORD:
1117                         case PW_CHAP_PASSWORD:
1118                         case PW_CHAP_CHALLENGE:
1119                         case PW_PROXY_STATE:
1120                         case PW_MESSAGE_AUTHENTICATOR:
1121                         case PW_EAP_MESSAGE:
1122                         case PW_STATE:
1123                                 continue;
1124                                 break;
1125
1126                                 /*
1127                                  *      By default, copy it over.
1128                                  */
1129                         default:
1130                                 break;
1131                         }
1132
1133                         /*
1134                          *      Don't copy from the head, we've already
1135                          *      checked it.
1136                          */
1137                         copy = paircopy2(vp, vp->attribute);
1138                         pairadd(&fake->packet->vps, copy);
1139                 }
1140         }
1141
1142 #ifndef NDEBUG
1143         if (debug_flag > 0) {
1144           printf("  TTLS: Sending tunneled request\n");
1145
1146           for (vp = fake->packet->vps; vp != NULL; vp = vp->next) {
1147             putchar('\t');vp_print(stdout, vp);putchar('\n');
1148           }
1149         }
1150 #endif
1151
1152         /*
1153          *      Call authentication recursively, which will
1154          *      do PAP, CHAP, MS-CHAP, etc.
1155          */
1156         rad_authenticate(fake);
1157
1158         /*
1159          *      Note that we don't do *anything* with the reply
1160          *      attributes.
1161          */
1162 #ifndef NDEBUG
1163         if (debug_flag > 0) {
1164           printf("  TTLS: Got tunneled reply RADIUS code %d\n",
1165                  fake->reply->code);
1166
1167           for (vp = fake->reply->vps; vp != NULL; vp = vp->next) {
1168             putchar('\t');vp_print(stdout, vp);putchar('\n');
1169           }
1170         }
1171 #endif
1172
1173         /*
1174          *      Decide what to do with the reply.
1175          */
1176         switch (fake->reply->code) {
1177         case 0:                 /* No reply code, must be proxied... */
1178                 vp = pairfind(fake->config_items, PW_PROXY_TO_REALM);
1179                 if (vp) {
1180                         eap_tunnel_data_t *tunnel;
1181                         DEBUG2("  TTLS: Tunneled authentication will be proxied to %s", vp->strvalue);
1182
1183                         /*
1184                          *      Tell the original request that it's going
1185                          *      to be proxied.
1186                          */
1187                         pairmove2(&(request->config_items),
1188                                   &(fake->config_items),
1189                                   PW_PROXY_TO_REALM);
1190
1191                         /*
1192                          *      Seed the proxy packet with the
1193                          *      tunneled request.
1194                          */
1195                         rad_assert(request->proxy == NULL);
1196                         request->proxy = fake->packet;
1197                         fake->packet = NULL;
1198                         rad_free(&fake->reply);
1199                         fake->reply = NULL;
1200
1201                         /*
1202                          *      Set up the callbacks for the tunnel
1203                          */
1204                         tunnel = rad_malloc(sizeof(*tunnel));
1205                         memset(tunnel, 0, sizeof(*tunnel));
1206
1207                         tunnel->tls_session = tls_session;
1208                         tunnel->callback = eapttls_postproxy;
1209
1210                         /*
1211                          *      Associate the callback with the request.
1212                          */
1213                         rcode = request_data_add(request,
1214                                                  request->proxy,
1215                                                  REQUEST_DATA_EAP_TUNNEL_CALLBACK,
1216                                                  tunnel, free);
1217                         rad_assert(rcode == 0);
1218
1219                         /*
1220                          *      rlm_eap.c has taken care of associating
1221                          *      the handler with the fake request.
1222                          *
1223                          *      So we associate the fake request with
1224                          *      this request.
1225                          */
1226                         rcode = request_data_add(request,
1227                                                  request->proxy,
1228                                                  REQUEST_DATA_EAP_MSCHAP_TUNNEL_CALLBACK,
1229                                                  fake, my_request_free);
1230                         rad_assert(rcode == 0);
1231                         fake = NULL;
1232
1233                         /*
1234                          *      Didn't authenticate the packet, but
1235                          *      we're proxying it.
1236                          */
1237                         rcode = PW_STATUS_CLIENT;
1238
1239                 } else {
1240                         DEBUG2("  TTLS: No tunneled reply was found for request %d , and the request was not proxied: rejecting the user.",
1241                                request->number);
1242                         rcode = PW_AUTHENTICATION_REJECT;
1243                 }
1244                 break;
1245
1246         default:
1247                 /*
1248                  *      Returns RLM_MODULE_FOO, and we want to return
1249                  *      PW_FOO
1250                  */
1251                 rcode = process_reply(handler, tls_session, request,
1252                                       fake->reply);
1253                 switch (rcode) {
1254                 case RLM_MODULE_REJECT:
1255                         rcode = PW_AUTHENTICATION_REJECT;
1256                         break;
1257
1258                 case RLM_MODULE_HANDLED:
1259                         rcode = PW_ACCESS_CHALLENGE;
1260                         break;
1261
1262                 case RLM_MODULE_OK:
1263                         rcode = PW_AUTHENTICATION_ACK;
1264                         break;
1265
1266                 default:
1267                         rcode = PW_AUTHENTICATION_REJECT;
1268                         break;
1269                 }
1270                 break;
1271         }
1272
1273         request_free(&fake);
1274
1275         return rcode;
1276 }