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

   1 /*
   2  * rlm_eap_ttls.c  contains the interfaces that are called from eap
   3  *
   4  * Version:     $Id$
   5  *
   6  *   This program is free software; you can redistribute it and/or modify
   7  *   it under the terms of the GNU General Public License as published by
   8  *   the Free Software Foundation; either version 2 of the License, or
   9  *   (at your option) any later version.
  10  *
  11  *   This program is distributed in the hope that it will be useful,
  12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *   GNU General Public License for more details.
  15  *
  16  *   You should have received a copy of the GNU General Public License
  17  *   along with this program; if not, write to the Free Software
  18  *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
  19  *
  20  *   Copyright 2003 Alan DeKok <aland@freeradius.org>
  21  *   Copyright 2006 The FreeRADIUS server project
  22  */
  23
  24 #include <freeradius-devel/ident.h>
  25 RCSID("$Id$")
  26
  27 #include "eap_ttls.h"
  28
  29 /*
  30  *    0                   1                   2                   3
  31  *    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
  32  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  33  *   |                           AVP Code                            |
  34  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  35  *   |V M r r r r r r|                  AVP Length                   |
  36  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  37  *   |                        Vendor-ID (opt)                        |
  38  *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  39  *   |    Data ...
  40  *   +-+-+-+-+-+-+-+-+
  41  */
  42
  43 /*
  44  *      Verify that the diameter packet is valid.
  45  */
  46 static int diameter_verify(const uint8_t *data, unsigned int data_len)
  47 {
  48         uint32_t attr;
  49         uint32_t length;
  50         unsigned int offset;
  51         unsigned int data_left = data_len;
  52
  53         while (data_left > 0) {
  54                 if (data_len < 12) {
  55                         DEBUG2("  rlm_eap_ttls:  Diameter attribute is too small to contain a Diameter header");
  56                         return 0;
  57                 }
  58
  59                 rad_assert(data_left <= data_len);
  60                 memcpy(&attr, data, sizeof(attr));
  61                 data += 4;
  62                 attr = ntohl(attr);
  63                 if (attr > 255) {
  64                         DEBUG2("  rlm_eap_ttls:  Non-RADIUS attribute in tunneled authentication is not supported");
  65                         return 0;
  66                 }
  67
  68                 memcpy(&length, data , sizeof(length));
  69                 data += 4;
  70                 length = ntohl(length);
  71
  72                 /*
  73                  *      A "vendor" flag, with a vendor ID of zero,
  74                  *      is equivalent to no vendor.  This is stupid.
  75                  */
  76                 offset = 8;
  77                 if ((length & (1 << 31)) != 0) {
  78                         int attribute;
  79                         uint32_t vendor;
  80                         DICT_ATTR *da;
  81
  82                         memcpy(&vendor, data, sizeof(vendor));
  83                         vendor = ntohl(vendor);
  84
  85                         if (vendor > 65535) {
  86                                 DEBUG2("  rlm_eap_ttls: Vendor codes larger than 65535 are not supported");
  87                                 return 0;
  88                         }
  89
  90                         attribute = (vendor << 16) | attr;
  91
  92                         da = dict_attrbyvalue(attribute);
  93
  94                         /*
  95                          *      SHOULD check ((length & (1 << 30)) != 0)
  96                          *      for the mandatory bit.
  97                          */
  98                         if (!da) {
  99                                 DEBUG2("  rlm_eap_ttls: Fatal! Vendor %u, Attribute %u was not found in our dictionary. ",
 100                                        vendor, attr);
 101                                 return 0;
 102                         }
 103
 104                         data += 4; /* skip the vendor field */
 105                         offset += 4; /* offset to value field */
 106                 }
 107
 108                 /*
 109                  *      Ignore the M bit.  We support all RADIUS attributes...
 110                  */
 111
 112                 /*
 113                  *      Get the length.  If it's too big, die.
 114                  */
 115                 length &= 0x00ffffff;
 116
 117                 /*
 118                  *      Too short or too long is bad.
 119                  *
 120                  *      FIXME: EAP-Message
 121                  */
 122                 if (length < offset) {
 123                         DEBUG2("  rlm_eap_ttls: Tunneled attribute %d is too short (%d)to contain anything useful.", attr, length);
 124                         return 0;
 125                 }
 126
 127                 if (length > (MAX_STRING_LEN + 8)) {
 128                         DEBUG2("  rlm_eap_ttls: Tunneled attribute %d is too long (%d) to pack into a RADIUS attribute.", attr, length);
 129                         return 0;
 130                 }
 131
 132                 if (length > data_left) {
 133                         DEBUG2("  rlm_eap_ttls: Tunneled attribute %d is longer than room left in the packet (%d > %d).", attr, length, data_left);
 134                         return 0;
 135                 }
 136
 137                 /*
 138                  *      Check for broken implementations, which don't
 139                  *      pad the AVP to a 4-octet boundary.
 140                  */
 141                 if (data_left == length) break;
 142
 143                 /*
 144                  *      The length does NOT include the padding, so
 145                  *      we've got to account for it here by rounding up
 146                  *      to the nearest 4-byte boundary.
 147                  */
 148                 length += 0x03;
 149                 length &= ~0x03;
 150
 151                 /*
 152                  *      If the rest of the diameter packet is larger than
 153                  *      this attribute, continue.
 154                  *
 155                  *      Otherwise, if the attribute over-flows the end
 156                  *      of the packet, die.
 157                  */
 158                 if (data_left < length) {
 159                         DEBUG2("  rlm_eap_ttls: ERROR! Diameter attribute overflows packet!");
 160                         return 0;
 161                 }
 162
 163                 /*
 164                  *      Check again for equality, now that we're padded
 165                  *      length to a multiple of 4 octets.
 166                  */
 167                 if (data_left == length) break;
 168
 169                 /*
 170                  *      data_left > length, continue.
 171                  */
 172                 data_left -= length;
 173                 data += length - offset;
 174         }
 175
 176         /*
 177          *      We got this far.  It looks OK.
 178          */
 179         return 1;
 180 }
 181
 182
 183 /*
 184  *      Convert diameter attributes to our VALUE_PAIR's
 185  */
 186 static VALUE_PAIR *diameter2vp(SSL *ssl,
 187                                const uint8_t *data, unsigned int data_len)
 188 {
 189         uint32_t        attr;
 190         uint32_t        length;
 191         unsigned int    offset;
 192         int             size;
 193         unsigned int    data_left = data_len;
 194         VALUE_PAIR      *first = NULL;
 195         VALUE_PAIR      **last = &first;
 196         VALUE_PAIR      *vp;
 197
 198         while (data_left > 0) {
 199                 rad_assert(data_left <= data_len);
 200                 memcpy(&attr, data, sizeof(attr));
 201                 data += 4;
 202                 attr = ntohl(attr);
 203
 204                 memcpy(&length, data, sizeof(length));
 205                 data += 4;
 206                 length = ntohl(length);
 207
 208                 /*
 209                  *      Ignore the M bit.  We support all RADIUS attributes...
 210                  */
 211
 212                 /*
 213                  *      A "vendor" flag, with a vendor ID of zero,
 214                  *      is equivalent to no vendor.  This is stupid.
 215                  */
 216                 offset = 8;
 217                 if ((length & (1 << 31)) != 0) {
 218                         uint32_t vendor;
 219
 220                         memcpy(&vendor, data, sizeof(vendor));
 221                         vendor = ntohl(vendor);
 222
 223                         attr |= (vendor << 16);
 224
 225                         data += 4; /* skip the vendor field, it's zero */
 226                         offset += 4; /* offset to value field */
 227                 }
 228
 229                 /*
 230                  *      Get the length.
 231                  */
 232                 length &= 0x00ffffff;
 233
 234                 /*
 235                  *      diameter code + length, and it must fit in
 236                  *      a VALUE_PAIR.
 237                  */
 238                 rad_assert(length <= (offset + MAX_STRING_LEN));
 239
 240                 /*
 241                  *      Get the size of the value portion of the
 242                  *      attribute.
 243                  */
 244                 size = length - offset;
 245
 246                 /*
 247                  *      Create it.
 248                  */
 249                 vp = paircreate(attr, PW_TYPE_OCTETS);
 250                 if (!vp) {
 251                         DEBUG2("  rlm_eap_ttls: Failure in creating VP");
 252                         pairfree(&first);
 253                         return NULL;
 254                 }
 255
 256                 /*
 257                  *      If it's a type from our dictionary, then
 258                  *      we need to put the data in a relevant place.
 259                  */
 260                 switch (vp->type) {
 261                 case PW_TYPE_INTEGER:
 262                 case PW_TYPE_DATE:
 263                         if (size != vp->length) {
 264                                 DEBUG2("  rlm_eap_ttls: Invalid length attribute %d",
 265                                        attr);
 266                                 pairfree(&first);
 267                                 pairfree(&vp);
 268                                 return NULL;
 269                         }
 270                         memcpy(&vp->vp_integer, data, vp->length);
 271
 272                         /*
 273                          *      Stored in host byte order: change it.
 274                          */
 275                         vp->vp_integer = ntohl(vp->vp_integer);
 276                         break;
 277
 278                 case PW_TYPE_IPADDR:
 279                         if (size != vp->length) {
 280                                 DEBUG2("  rlm_eap_ttls: Invalid length attribute %d",
 281                                        attr);
 282                                 pairfree(&first);
 283                                 pairfree(&vp);
 284                                 return NULL;
 285                         }
 286                   memcpy(&vp->vp_ipaddr, data, vp->length);
 287
 288                   /*
 289                    *    Stored in network byte order: don't change it.
 290                    */
 291                   break;
 292
 293                   /*
 294                    *    String, octet, etc.  Copy the data from the
 295                    *    value field over verbatim.
 296                    *
 297                    *    FIXME: Ipv6 attributes ?
 298                    *
 299                    */
 300                 default:
 301                         vp->length = size;
 302                         memcpy(vp->vp_strvalue, data, vp->length);
 303                         break;
 304                 }
 305
 306                 /*
 307                  *      User-Password is NUL padded to a multiple
 308                  *      of 16 bytes.  Let's chop it to something
 309                  *      more reasonable.
 310                  *
 311                  *      NOTE: This means that the User-Password
 312                  *      attribute CANNOT EVER have embedded zeros in it!
 313                  */
 314                 switch (vp->attribute) {
 315                 case PW_USER_PASSWORD:
 316                         rad_assert(vp->length <= 128); /* RFC requirements */
 317
 318                         /*
 319                          *      If the password is exactly 16 octets,
 320                          *      it won't be zero-terminated.
 321                          */
 322                         vp->vp_strvalue[vp->length] = '\0';
 323                         vp->length = strlen(vp->vp_strvalue);
 324                         break;
 325
 326                         /*
 327                          *      Ensure that the client is using the
 328                          *      correct challenge.  This weirdness is
 329                          *      to protect against against replay
 330                          *      attacks, where anyone observing the
 331                          *      CHAP exchange could pose as that user,
 332                          *      by simply choosing to use the same
 333                          *      challenge.
 334                          *
 335                          *      By using a challenge based on
 336                          *      information from the current session,
 337                          *      we can guarantee that the client is
 338                          *      not *choosing* a challenge.
 339                          *
 340                          *      We're a little forgiving in that we
 341                          *      have loose checks on the length, and
 342                          *      we do NOT check the Id (first octet of
 343                          *      the response to the challenge)
 344                          *
 345                          *      But if the client gets the challenge correct,
 346                          *      we're not too worried about the Id.
 347                          */
 348                 case PW_CHAP_CHALLENGE:
 349                 case PW_MSCHAP_CHALLENGE:
 350                         if ((vp->length < 8) ||
 351                             (vp->length > 16)) {
 352                                 DEBUG2("  TTLS: Tunneled challenge has invalid length");
 353                                 pairfree(&first);
 354                                 pairfree(&vp);
 355                                 return NULL;
 356
 357                         } else {
 358                                 uint8_t challenge[16];
 359
 360                                 eapttls_gen_challenge(ssl, challenge,
 361                                                       sizeof(challenge));
 362
 363                                 if (memcmp(challenge, vp->vp_octets,
 364                                            vp->length) != 0) {
 365                                         DEBUG2("  TTLS: Tunneled challenge is incorrect");
 366                                         pairfree(&first);
 367                                         pairfree(&vp);
 368                                         return NULL;
 369                                 }
 370                         }
 371                         break;
 372
 373                 default:
 374                         break;
 375                 } /* switch over checking/re-writing of attributes. */
 376
 377                 /*
 378                  *      Update the list.
 379                  */
 380                 *last = vp;
 381                 last = &(vp->next);
 382
 383                 /*
 384                  *      Catch non-aligned attributes.
 385                  */
 386                 if (data_left == length) break;
 387
 388                 /*
 389                  *      The length does NOT include the padding, so
 390                  *      we've got to account for it here by rounding up
 391                  *      to the nearest 4-byte boundary.
 392                  */
 393                 length += 0x03;
 394                 length &= ~0x03;
 395
 396                 rad_assert(data_left >= length);
 397                 data_left -= length;
 398                 data += length - offset; /* already updated */
 399         }
 400
 401         /*
 402          *      We got this far.  It looks OK.
 403          */
 404         return first;
 405 }
 406
 407 /*
 408  *      Convert VALUE_PAIR's to diameter attributes, and write them
 409  *      to an SSL session.
 410  *
 411  *      The ONLY VALUE_PAIR's which may be passed to this function
 412  *      are ones which can go inside of a RADIUS (i.e. diameter)
 413  *      packet.  So no server-configuration attributes, or the like.
 414  */
 415 static int vp2diameter(tls_session_t *tls_session, VALUE_PAIR *first)
 416 {
 417         /*
 418          *      RADIUS packets are no more than 4k in size, so if
 419          *      we've got more than 4k of data to write, it's very
 420          *      bad.
 421          */
 422         uint8_t         buffer[4096];
 423         uint8_t         *p;
 424         uint32_t        attr;
 425         uint32_t        length;
 426         uint32_t        vendor;
 427         size_t          total;
 428         VALUE_PAIR      *vp;
 429
 430         p = buffer;
 431         total = 0;
 432
 433         for (vp = first; vp != NULL; vp = vp->next) {
 434                 /*
 435                  *      Too much data: die.
 436                  */
 437                 if ((total + vp->length + 12) >= sizeof(buffer)) {
 438                         DEBUG2("  TTLS output buffer is full!");
 439                         return 0;
 440                 }
 441
 442                 /*
 443                  *      Hmm... we don't group multiple EAP-Messages
 444                  *      together.  Maybe we should...
 445                  */
 446
 447                 /*
 448                  *      Length is no more than 253, due to RADIUS
 449                  *      issues.
 450                  */
 451                 length = vp->length;
 452                 vendor = (vp->attribute >> 16) & 0xffff;
 453                 if (vendor != 0) {
 454                         attr = vp->attribute & 0xffff;
 455                         length |= (1 << 31);
 456                 } else {
 457                         attr = vp->attribute;
 458                 }
 459
 460                 /*
 461                  *      Hmm... set the M bit for all attributes?
 462                  */
 463                 length |= (1 << 30);
 464
 465                 attr = ntohl(attr);
 466
 467                 memcpy(p, &attr, sizeof(attr));
 468                 p += 4;
 469                 total += 4;
 470
 471                 length += 8;    /* includes 8 bytes of attr & length */
 472
 473                 if (vendor != 0) {
 474                         length += 4; /* include 4 bytes of vendor */
 475
 476                         length = ntohl(length);
 477                         memcpy(p, &length, sizeof(length));
 478                         p += 4;
 479                         total += 4;
 480
 481                         vendor = ntohl(vendor);
 482                         memcpy(p, &vendor, sizeof(vendor));
 483                         p += 4;
 484                         total += 4;
 485                 } else {
 486                         length = ntohl(length);
 487                         memcpy(p, &length, sizeof(length));
 488                         p += 4;
 489                         total += 4;
 490                 }
 491
 492                 switch (vp->type) {
 493                 case PW_TYPE_INTEGER:
 494                 case PW_TYPE_DATE:
 495                         attr = ntohl(vp->vp_integer); /* stored in host order */
 496                         memcpy(p, &attr, sizeof(attr));
 497                         length = 4;
 498                         break;
 499
 500                 case PW_TYPE_IPADDR:
 501                         memcpy(p, &vp->vp_ipaddr, 4); /* network order */
 502                         length = 4;
 503                         break;
 504
 505                 case PW_TYPE_STRING:
 506                 case PW_TYPE_OCTETS:
 507                 default:
 508                         memcpy(p, vp->vp_strvalue, vp->length);
 509                         length = vp->length;
 510                         break;
 511                 }
 512
 513                 /*
 514                  *      Skip to the end of the data.
 515                  */
 516                 p += length;
 517                 total += length;
 518
 519                 /*
 520                  *      Align the data to a multiple of 4 bytes.
 521                  */
 522                 if ((total & 0x03) != 0) {
 523                         unsigned int i;
 524
 525                         length = 4 - (total & 0x03);
 526                         for (i = 0; i < length; i++) {
 527                                 *p = '\0';
 528                                 p++;
 529                                 total++;
 530                         }
 531                 }
 532         } /* loop over the VP's to write. */
 533
 534         /*
 535          *      Write the data in the buffer to the SSL session.
 536          */
 537         if (total > 0) {
 538 #ifndef NDEBUG
 539                 unsigned int i;
 540
 541                 if (debug_flag > 2) {
 542                         for (i = 0; i < total; i++) {
 543                                 if ((i & 0x0f) == 0) printf("  TTLS tunnel data out %04x: ", i);
 544
 545                                 printf("%02x ", buffer[i]);
 546
 547                                 if ((i & 0x0f) == 0x0f) printf("\n");
 548                         }
 549                         if ((total & 0x0f) != 0) printf("\n");
 550                 }
 551 #endif
 552
 553                 (tls_session->record_plus)(&tls_session->clean_in, buffer, total);
 554
 555                 /*
 556                  *      FIXME: Check the return code.
 557                  */
 558                 tls_handshake_send(tls_session);
 559         }
 560
 561         /*
 562          *      Everything's OK.
 563          */
 564         return 1;
 565 }
 566
 567 /*
 568  *      Use a reply packet to determine what to do.
 569  */
 570 static int process_reply(EAP_HANDLER *handler, tls_session_t *tls_session,
 571                          REQUEST *request, RADIUS_PACKET *reply)
 572 {
 573         int rcode = RLM_MODULE_REJECT;
 574         VALUE_PAIR *vp;
 575         ttls_tunnel_t *t = tls_session->opaque;
 576
 577         handler = handler;      /* -Wunused */
 578
 579         /*
 580          *      If the response packet was Access-Accept, then
 581          *      we're OK.  If not, die horribly.
 582          *
 583          *      FIXME: Take MS-CHAP2-Success attribute, and
 584          *      tunnel it back to the client, to authenticate
 585          *      ourselves to the client.
 586          *
 587          *      FIXME: If we have an Access-Challenge, then
 588          *      the Reply-Message is tunneled back to the client.
 589          *
 590          *      FIXME: If we have an EAP-Message, then that message
 591          *      must be tunneled back to the client.
 592          *
 593          *      FIXME: If we have an Access-Challenge with a State
 594          *      attribute, then do we tunnel that to the client, or
 595          *      keep track of it ourselves?
 596          *
 597          *      FIXME: EAP-Messages can only start with 'identity',
 598          *      NOT 'eap start', so we should check for that....
 599          */
 600         switch (reply->code) {
 601         case PW_AUTHENTICATION_ACK:
 602                 DEBUG2("  TTLS: Got tunneled Access-Accept");
 603
 604                 rcode = RLM_MODULE_OK;
 605
 606                 /*
 607                  *      MS-CHAP2-Success means that we do NOT return
 608                  *      an Access-Accept, but instead tunnel that
 609                  *      attribute to the client, and keep going with
 610                  *      the TTLS session.  Once the client accepts
 611                  *      our identity, it will respond with an empty
 612                  *      packet, and we will send EAP-Success.
 613                  */
 614                 vp = NULL;
 615                 pairmove2(&vp, &reply->vps, PW_MSCHAP2_SUCCESS);
 616                 if (vp) {
 617                         DEBUG2("  TTLS: Got MS-CHAP2-Success, tunneling it to the client in a challenge.");
 618                         rcode = RLM_MODULE_HANDLED;
 619                         t->authenticated = TRUE;
 620
 621                         /*
 622                          *      Delete MPPE keys & encryption policy.  We don't
 623                          *      want these here.
 624                          */
 625                         pairdelete(&reply->vps, ((311 << 16) | 7));
 626                         pairdelete(&reply->vps, ((311 << 16) | 8));
 627                         pairdelete(&reply->vps, ((311 << 16) | 16));
 628                         pairdelete(&reply->vps, ((311 << 16) | 17));
 629
 630                         /*
 631                          *      Use the tunneled reply, but not now.
 632                          */
 633                         if (t->use_tunneled_reply) {
 634                                 t->reply = reply->vps;
 635                                 reply->vps = NULL;
 636                         }
 637
 638                 } else { /* no MS-CHAP2-Success */
 639                         /*
 640                          *      Can only have EAP-Message if there's
 641                          *      no MS-CHAP2-Success.  (FIXME: EAP-MSCHAP?)
 642                          *
 643                          *      We also do NOT tunnel the EAP-Success
 644                          *      attribute back to the client, as the client
 645                          *      can figure it out, from the non-tunneled
 646                          *      EAP-Success packet.
 647                          */
 648                         pairmove2(&vp, &reply->vps, PW_EAP_MESSAGE);
 649                         pairfree(&vp);
 650                 }
 651
 652                 /*
 653                  *      Handle the ACK, by tunneling any necessary reply
 654                  *      VP's back to the client.
 655                  */
 656                 if (vp) {
 657                         vp2diameter(tls_session, vp);
 658                         pairfree(&vp);
 659                 }
 660
 661                 /*
 662                  *      If we've been told to use the attributes from
 663                  *      the reply, then do so.
 664                  *
 665                  *      WARNING: This may leak information about the
 666                  *      tunneled user!
 667                  */
 668                 if (t->use_tunneled_reply) {
 669                         pairdelete(&reply->vps, PW_PROXY_STATE);
 670                         pairadd(&request->reply->vps, reply->vps);
 671                         reply->vps = NULL;
 672                 }
 673                 break;
 674
 675
 676         case PW_AUTHENTICATION_REJECT:
 677                 DEBUG2("  TTLS: Got tunneled Access-Reject");
 678                 rcode = RLM_MODULE_REJECT;
 679                 break;
 680
 681                 /*
 682                  *      Handle Access-Challenge, but only if we
 683                  *      send tunneled reply data.  This is because
 684                  *      an Access-Challenge means that we MUST tunnel
 685                  *      a Reply-Message to the client.
 686                  */
 687         case PW_ACCESS_CHALLENGE:
 688                 DEBUG2("  TTLS: Got tunneled Access-Challenge");
 689
 690                 /*
 691                  *      Keep the State attribute, if necessary.
 692                  *
 693                  *      Get rid of the old State, too.
 694                  */
 695                 pairfree(&t->state);
 696                 pairmove2(&t->state, &reply->vps, PW_STATE);
 697
 698                 /*
 699                  *      We should really be a bit smarter about this,
 700                  *      and move over only those attributes which
 701                  *      are relevant to the authentication request,
 702                  *      but that's a lot more work, and this "dumb"
 703                  *      method works in 99.9% of the situations.
 704                  */
 705                 vp = NULL;
 706                 pairmove2(&vp, &reply->vps, PW_EAP_MESSAGE);
 707
 708                 /*
 709                  *      There MUST be a Reply-Message in the challenge,
 710                  *      which we tunnel back to the client.
 711                  *
 712                  *      If there isn't one in the reply VP's, then
 713                  *      we MUST create one, with an empty string as
 714                  *      it's value.
 715                  */
 716                 pairmove2(&vp, &reply->vps, PW_REPLY_MESSAGE);
 717
 718                 /*
 719                  *      Handle the ACK, by tunneling any necessary reply
 720                  *      VP's back to the client.
 721                  */
 722                 if (vp) {
 723                         vp2diameter(tls_session, vp);
 724                         pairfree(&vp);
 725                 }
 726                 rcode = RLM_MODULE_HANDLED;
 727                 break;
 728
 729         default:
 730                 DEBUG2("  TTLS: Unknown RADIUS packet type %d: rejecting tunneled user", reply->code);
 731                 rcode = RLM_MODULE_INVALID;
 732                 break;
 733         }
 734
 735         return rcode;
 736 }
 737
 738
 739 /*
 740  *      Do post-proxy processing,
 741  */
 742 static int eapttls_postproxy(EAP_HANDLER *handler, void *data)
 743 {
 744         int rcode;
 745         tls_session_t *tls_session = (tls_session_t *) data;
 746         REQUEST *fake;
 747
 748         DEBUG2("  TTLS: Passing reply from proxy back into the tunnel.");
 749
 750         /*
 751          *      If there was a fake request associated with the proxied
 752          *      request, do more processing of it.
 753          */
 754         fake = (REQUEST *) request_data_get(handler->request,
 755                                             handler->request->proxy,
 756                                             REQUEST_DATA_EAP_MSCHAP_TUNNEL_CALLBACK);
 757
 758         /*
 759          *      Do the callback, if it exists, and if it was a success.
 760          */
 761         if (fake && (handler->request->proxy_reply->code == PW_AUTHENTICATION_ACK)) {
 762                 VALUE_PAIR *vp;
 763                 REQUEST *request = handler->request;
 764
 765                 /*
 766                  *      Terrible hacks.
 767                  */
 768                 rad_assert(fake->packet == NULL);
 769                 fake->packet = request->proxy;
 770                 request->proxy = NULL;
 771
 772                 rad_assert(fake->reply == NULL);
 773                 fake->reply = request->proxy_reply;
 774                 request->proxy_reply = NULL;
 775
 776                 /*
 777                  *      Perform a post-auth stage for the tunneled
 778                  *      session.
 779                  */
 780                 fake->options &= ~RAD_REQUEST_OPTION_PROXY_EAP;
 781                 rcode = rad_postauth(fake);
 782                 DEBUG2("  POST-AUTH %d", rcode);
 783
 784 #ifndef NDEBUG
 785                 if (debug_flag > 0) {
 786                         printf("  TTLS: Final reply from tunneled session code %d\n",
 787                                fake->reply->code);
 788
 789                         for (vp = fake->reply->vps; vp != NULL; vp = vp->next) {
 790                                 putchar('\t');vp_print(stdout, vp);putchar('\n');
 791                         }
 792                 }
 793 #endif
 794
 795                 /*
 796                  *      Terrible hacks.
 797                  */
 798                 request->proxy = fake->packet;
 799                 fake->packet = NULL;
 800                 request->proxy_reply = fake->reply;
 801                 fake->reply = NULL;
 802
 803                 /*
 804                  *      And we're done with this request.
 805                  */
 806
 807                 switch (rcode) {
 808                 case RLM_MODULE_FAIL:
 809                         request_free(&fake);
 810                         eaptls_fail(handler->eap_ds, 0);
 811                         return 0;
 812                         break;
 813
 814                 default:  /* Don't Do Anything */
 815                         DEBUG2(" TTLS: Got reply %d",
 816                                request->proxy_reply->code);
 817                         break;
 818                 }
 819         }
 820         request_free(&fake);    /* robust if fake == NULL */
 821
 822         /*
 823          *      Process the reply from the home server.
 824          */
 825         rcode = process_reply(handler, tls_session, handler->request,
 826                               handler->request->proxy_reply);
 827
 828         /*
 829          *      The proxy code uses the reply from the home server as
 830          *      the basis for the reply to the NAS.  We don't want that,
 831          *      so we toss it, after we've had our way with it.
 832          */
 833         pairfree(&handler->request->proxy_reply->vps);
 834
 835         switch (rcode) {
 836         case RLM_MODULE_REJECT:
 837                 DEBUG2("  TTLS: Reply was rejected");
 838                 break;
 839
 840         case RLM_MODULE_HANDLED:
 841                 DEBUG2("  TTLS: Reply was handled");
 842                 eaptls_request(handler->eap_ds, tls_session);
 843                 return 1;
 844
 845         case RLM_MODULE_OK:
 846                 DEBUG2("  TTLS: Reply was OK");
 847                 eaptls_success(handler->eap_ds, 0);
 848                 eaptls_gen_mppe_keys(&handler->request->reply->vps,
 849                                      tls_session->ssl,
 850                                      "ttls keying material");
 851                 return 1;
 852
 853         default:
 854                 DEBUG2("  TTLS: Reply was unknown.");
 855                 break;
 856         }
 857
 858         eaptls_fail(handler->eap_ds, 0);
 859         return 0;
 860 }
 861
 862
 863 /*
 864  *      Free a request.
 865  */
 866 static void my_request_free(void *data)
 867 {
 868         REQUEST *request = (REQUEST *)data;
 869
 870         request_free(&request);
 871 }
 872
 873
 874 /*
 875  *      Process the "diameter" contents of the tunneled data.
 876  */
 877 int eapttls_process(EAP_HANDLER *handler, tls_session_t *tls_session)
 878 {
 879         int err;
 880         int rcode = PW_AUTHENTICATION_REJECT;
 881         REQUEST *fake;
 882         VALUE_PAIR *vp;
 883         ttls_tunnel_t *t;
 884         const uint8_t *data;
 885         unsigned int data_len;
 886         char buffer[1024];
 887         REQUEST *request = handler->request;
 888
 889         /*
 890          *      Grab the dirty data, and copy it to our buffer.
 891          *
 892          *      I *really* don't like these 'record_t' things...
 893          */
 894         data_len = (tls_session->record_minus)(&tls_session->dirty_in, buffer, sizeof(buffer));
 895         data = buffer;
 896
 897         /*
 898          *      Write the data from the dirty buffer (i.e. packet
 899          *      data) into the buffer which we will give to SSL for
 900          *      decoding.
 901          *
 902          *      Some of this code COULD technically go into the TLS
 903          *      module, in eaptls_process(), where it returns EAPTLS_OK.
 904          *
 905          *      Similarly, the writing of data to the SSL context could
 906          *      go there, too...
 907          */
 908         BIO_write(tls_session->into_ssl, buffer, data_len);
 909         (tls_session->record_init)(&tls_session->clean_out);
 910
 911         /*
 912          *      Read (and decrypt) the tunneled data from the SSL session,
 913          *      and put it into the decrypted data buffer.
 914          */
 915         err = SSL_read(tls_session->ssl, tls_session->clean_out.data,
 916                        sizeof(tls_session->clean_out.data));
 917         if (err < 0) {
 918                 /*
 919                  *      FIXME: Call SSL_get_error() to see what went
 920                  *      wrong.
 921                  */
 922                 radlog(L_INFO, "rlm_eap_ttls: SSL_read Error");
 923                 return PW_AUTHENTICATION_REJECT;
 924         }
 925
 926         t = (ttls_tunnel_t *) tls_session->opaque;
 927
 928         /*
 929          *      If there's no data, maybe this is an ACK to an
 930          *      MS-CHAP2-Success.
 931          */
 932         if (err == 0) {
 933                 if (t->authenticated) {
 934                         DEBUG2("  TTLS: Got ACK, and the user was already authenticated.");
 935                         return PW_AUTHENTICATION_ACK;
 936                 } /* else no session, no data, die. */
 937
 938                 /*
 939                  *      FIXME: Call SSL_get_error() to see what went
 940                  *      wrong.
 941                  */
 942                 radlog(L_INFO, "rlm_eap_ttls: SSL_read Error");
 943                 return PW_AUTHENTICATION_REJECT;
 944         }
 945
 946         data_len = tls_session->clean_out.used = err;
 947         data = tls_session->clean_out.data;
 948
 949 #ifndef NDEBUG
 950         if (debug_flag > 2) {
 951                 unsigned int i;
 952
 953                 for (i = 0; i < data_len; i++) {
 954                         if ((i & 0x0f) == 0) printf("  TTLS tunnel data in %04x: ", i);
 955
 956                         printf("%02x ", data[i]);
 957
 958                         if ((i & 0x0f) == 0x0f) printf("\n");
 959                 }
 960                 if ((data_len & 0x0f) != 0) printf("\n");
 961         }
 962 #endif
 963
 964         if (!diameter_verify(data, data_len)) {
 965                 return PW_AUTHENTICATION_REJECT;
 966         }
 967
 968         /*
 969          *      Allocate a fake REQUEST structe.
 970          */
 971         fake = request_alloc_fake(request);
 972
 973         rad_assert(fake->packet->vps == NULL);
 974
 975         /*
 976          *      Add the tunneled attributes to the fake request.
 977          */
 978         fake->packet->vps = diameter2vp(tls_session->ssl, data, data_len);
 979         if (!fake->packet->vps) {
 980                 return PW_AUTHENTICATION_REJECT;
 981         }
 982
 983         /*
 984          *      Tell the request that it's a fake one.
 985          */
 986         vp = pairmake("Freeradius-Proxied-To", "127.0.0.1", T_OP_EQ);
 987         if (vp) {
 988                 pairadd(&fake->packet->vps, vp);
 989         }
 990
 991 #ifndef NDEBUG
 992         if (debug_flag > 0) {
 993                 printf("  TTLS: Got tunneled request\n");
 994
 995                 for (vp = fake->packet->vps; vp != NULL; vp = vp->next) {
 996                         putchar('\t');vp_print(stdout, vp);putchar('\n');
 997                 }
 998         }
 999 #endif
1000
1001         /*
1002          *      Update other items in the REQUEST data structure.
1003          */
1004         fake->username = pairfind(fake->packet->vps, PW_USER_NAME);
1005         fake->password = pairfind(fake->packet->vps, PW_USER_PASSWORD);
1006
1007         /*
1008          *      No User-Name, try to create one from stored data.
1009          */
1010         if (!fake->username) {
1011                 /*
1012                  *      No User-Name in the stored data, look for
1013                  *      an EAP-Identity, and pull it out of there.
1014                  */
1015                 if (!t->username) {
1016                         vp = pairfind(fake->packet->vps, PW_EAP_MESSAGE);
1017                         if (vp &&
1018                             (vp->length >= EAP_HEADER_LEN + 2) &&
1019                             (vp->vp_strvalue[0] == PW_EAP_RESPONSE) &&
1020                             (vp->vp_strvalue[EAP_HEADER_LEN] == PW_EAP_IDENTITY) &&
1021                             (vp->vp_strvalue[EAP_HEADER_LEN + 1] != 0)) {
1022                                 /*
1023                                  *      Create & remember a User-Name
1024                                  */
1025                                 t->username = pairmake("User-Name", "", T_OP_EQ);
1026                                 rad_assert(t->username != NULL);
1027
1028                                 memcpy(t->username->vp_strvalue, vp->vp_strvalue + 5,
1029                                        vp->length - 5);
1030                                 t->username->length = vp->length - 5;
1031                                 t->username->vp_strvalue[t->username->length] = 0;
1032
1033                                 DEBUG2("  TTLS: Got tunneled identity of %s",
1034                                        t->username->vp_strvalue);
1035
1036                                 /*
1037                                  *      If there's a default EAP type,
1038                                  *      set it here.
1039                                  */
1040                                 if (t->default_eap_type != 0) {
1041                                         DEBUG2("  TTLS: Setting default EAP type for tunneled EAP session.");
1042                                         vp = paircreate(PW_EAP_TYPE,
1043                                                         PW_TYPE_INTEGER);
1044                                         rad_assert(vp != NULL);
1045                                         vp->vp_integer = t->default_eap_type;
1046                                         pairadd(&fake->config_items, vp);
1047                                 }
1048
1049                         } else {
1050                                 /*
1051                                  *      Don't reject the request outright,
1052                                  *      as it's permitted to do EAP without
1053                                  *      user-name.
1054                                  */
1055                                 DEBUG2("  rlm_eap_ttls: WARNING! No EAP-Identity found to start EAP conversation.");
1056                         }
1057                 } /* else there WAS a t->username */
1058
1059                 if (t->username) {
1060                         vp = paircopy(t->username);
1061                         pairadd(&fake->packet->vps, vp);
1062                         fake->username = pairfind(fake->packet->vps, PW_USER_NAME);
1063                 }
1064         } /* else the request ALREADY had a User-Name */
1065
1066         /*
1067          *      Add the State attribute, too, if it exists.
1068          */
1069         if (t->state) {
1070                 DEBUG2("  TTLS: Adding old state with %02x %02x",
1071                        t->state->vp_strvalue[0], t->state->vp_strvalue[1]);
1072                 vp = paircopy(t->state);
1073                 if (vp) pairadd(&fake->packet->vps, vp);
1074         }
1075
1076         /*
1077          *      If this is set, we copy SOME of the request attributes
1078          *      from outside of the tunnel to inside of the tunnel.
1079          *
1080          *      We copy ONLY those attributes which do NOT already
1081          *      exist in the tunneled request.
1082          */
1083         if (t->copy_request_to_tunnel) {
1084                 VALUE_PAIR *copy;
1085
1086                 for (vp = request->packet->vps; vp != NULL; vp = vp->next) {
1087                         /*
1088                          *      The attribute is a server-side thingy,
1089                          *      don't copy it.
1090                          */
1091                         if ((vp->attribute > 255) &&
1092                             (((vp->attribute >> 16) & 0xffff) == 0)) {
1093                                 continue;
1094                         }
1095
1096                         /*
1097                          *      The outside attribute is already in the
1098                          *      tunnel, don't copy it.
1099                          *
1100                          *      This works for BOTH attributes which
1101                          *      are originally in the tunneled request,
1102                          *      AND attributes which are copied there
1103                          *      from below.
1104                          */
1105                         if (pairfind(fake->packet->vps, vp->attribute)) {
1106                                 continue;
1107                         }
1108
1109                         /*
1110                          *      Some attributes are handled specially.
1111                          */
1112                         switch (vp->attribute) {
1113                                 /*
1114                                  *      NEVER copy Message-Authenticator,
1115                                  *      EAP-Message, or State.  They're
1116                                  *      only for outside of the tunnel.
1117                                  */
1118                         case PW_USER_NAME:
1119                         case PW_USER_PASSWORD:
1120                         case PW_CHAP_PASSWORD:
1121                         case PW_CHAP_CHALLENGE:
1122                         case PW_PROXY_STATE:
1123                         case PW_MESSAGE_AUTHENTICATOR:
1124                         case PW_EAP_MESSAGE:
1125                         case PW_STATE:
1126                                 continue;
1127                                 break;
1128
1129                                 /*
1130                                  *      By default, copy it over.
1131                                  */
1132                         default:
1133                                 break;
1134                         }
1135
1136                         /*
1137                          *      Don't copy from the head, we've already
1138                          *      checked it.
1139                          */
1140                         copy = paircopy2(vp, vp->attribute);
1141                         pairadd(&fake->packet->vps, copy);
1142                 }
1143         }
1144
1145 #ifndef NDEBUG
1146         if (debug_flag > 0) {
1147           printf("  TTLS: Sending tunneled request\n");
1148
1149           for (vp = fake->packet->vps; vp != NULL; vp = vp->next) {
1150             putchar('\t');vp_print(stdout, vp);putchar('\n');
1151           }
1152         }
1153 #endif
1154
1155         /*
1156          *      Call authentication recursively, which will
1157          *      do PAP, CHAP, MS-CHAP, etc.
1158          */
1159         rad_authenticate(fake);
1160
1161         /*
1162          *      Note that we don't do *anything* with the reply
1163          *      attributes.
1164          */
1165 #ifndef NDEBUG
1166         if (debug_flag > 0) {
1167           printf("  TTLS: Got tunneled reply RADIUS code %d\n",
1168                  fake->reply->code);
1169
1170           for (vp = fake->reply->vps; vp != NULL; vp = vp->next) {
1171             putchar('\t');vp_print(stdout, vp);putchar('\n');
1172           }
1173         }
1174 #endif
1175
1176         /*
1177          *      Decide what to do with the reply.
1178          */
1179         switch (fake->reply->code) {
1180         case 0:                 /* No reply code, must be proxied... */
1181                 vp = pairfind(fake->config_items, PW_PROXY_TO_REALM);
1182                 if (vp) {
1183                         eap_tunnel_data_t *tunnel;
1184                         DEBUG2("  TTLS: Tunneled authentication will be proxied to %s", vp->vp_strvalue);
1185
1186                         /*
1187                          *      Tell the original request that it's going
1188                          *      to be proxied.
1189                          */
1190                         pairmove2(&(request->config_items),
1191                                   &(fake->config_items),
1192                                   PW_PROXY_TO_REALM);
1193
1194                         /*
1195                          *      Seed the proxy packet with the
1196                          *      tunneled request.
1197                          */
1198                         rad_assert(request->proxy == NULL);
1199                         request->proxy = fake->packet;
1200                         fake->packet = NULL;
1201                         rad_free(&fake->reply);
1202                         fake->reply = NULL;
1203
1204                         /*
1205                          *      Set up the callbacks for the tunnel
1206                          */
1207                         tunnel = rad_malloc(sizeof(*tunnel));
1208                         memset(tunnel, 0, sizeof(*tunnel));
1209
1210                         tunnel->tls_session = tls_session;
1211                         tunnel->callback = eapttls_postproxy;
1212
1213                         /*
1214                          *      Associate the callback with the request.
1215                          */
1216                         rcode = request_data_add(request,
1217                                                  request->proxy,
1218                                                  REQUEST_DATA_EAP_TUNNEL_CALLBACK,
1219                                                  tunnel, free);
1220                         rad_assert(rcode == 0);
1221
1222                         /*
1223                          *      rlm_eap.c has taken care of associating
1224                          *      the handler with the fake request.
1225                          *
1226                          *      So we associate the fake request with
1227                          *      this request.
1228                          */
1229                         rcode = request_data_add(request,
1230                                                  request->proxy,
1231                                                  REQUEST_DATA_EAP_MSCHAP_TUNNEL_CALLBACK,
1232                                                  fake, my_request_free);
1233                         rad_assert(rcode == 0);
1234                         fake = NULL;
1235
1236                         /*
1237                          *      Didn't authenticate the packet, but
1238                          *      we're proxying it.
1239                          */
1240                         rcode = PW_STATUS_CLIENT;
1241
1242                 } else {
1243                         DEBUG2("  TTLS: No tunneled reply was found for request %d , and the request was not proxied: rejecting the user.",
1244                                request->number);
1245                         rcode = PW_AUTHENTICATION_REJECT;
1246                 }
1247                 break;
1248
1249         default:
1250                 /*
1251                  *      Returns RLM_MODULE_FOO, and we want to return
1252                  *      PW_FOO
1253                  */
1254                 rcode = process_reply(handler, tls_session, request,
1255                                       fake->reply);
1256                 switch (rcode) {
1257                 case RLM_MODULE_REJECT:
1258                         rcode = PW_AUTHENTICATION_REJECT;
1259                         break;
1260
1261                 case RLM_MODULE_HANDLED:
1262                         rcode = PW_ACCESS_CHALLENGE;
1263                         break;
1264
1265                 case RLM_MODULE_OK:
1266                         rcode = PW_AUTHENTICATION_ACK;
1267                         break;
1268
1269                 default:
1270                         rcode = PW_AUTHENTICATION_REJECT;
1271                         break;
1272                 }
1273                 break;
1274         }
1275
1276         request_free(&fake);
1277
1278         return rcode;
1279 }