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                 if (length < offset) {
 121                         DEBUG2("  rlm_eap_ttls: Tunneled attribute %d is too short (%d)to contain anything useful.", attr, length);
 122                         return 0;
 123                 }
 124
 125                 /*
 126                  *      EAP Messages cane be longer than MAX_STRING_LEN.
 127                  *      Other attributes cannot be.
 128                  */
 129                 if ((attr != PW_EAP_MESSAGE) &&
 130                     (length > (MAX_STRING_LEN + 8))) {
 131                         DEBUG2("  rlm_eap_ttls: Tunneled attribute %d is too long (%d) to pack into a RADIUS attribute.", attr, length);
 132                         return 0;
 133                 }
 134
 135                 if (length > data_left) {
 136                         DEBUG2("  rlm_eap_ttls: Tunneled attribute %d is longer than room left in the packet (%d > %d).", attr, length, data_left);
 137                         return 0;
 138                 }
 139
 140                 /*
 141                  *      Check for broken implementations, which don't
 142                  *      pad the AVP to a 4-octet boundary.
 143                  */
 144                 if (data_left == length) break;
 145
 146                 /*
 147                  *      The length does NOT include the padding, so
 148                  *      we've got to account for it here by rounding up
 149                  *      to the nearest 4-byte boundary.
 150                  */
 151                 length += 0x03;
 152                 length &= ~0x03;
 153
 154                 /*
 155                  *      If the rest of the diameter packet is larger than
 156                  *      this attribute, continue.
 157                  *
 158                  *      Otherwise, if the attribute over-flows the end
 159                  *      of the packet, die.
 160                  */
 161                 if (data_left < length) {
 162                         DEBUG2("  rlm_eap_ttls: ERROR! Diameter attribute overflows packet!");
 163                         return 0;
 164                 }
 165
 166                 /*
 167                  *      Check again for equality, now that we're padded
 168                  *      length to a multiple of 4 octets.
 169                  */
 170                 if (data_left == length) break;
 171
 172                 /*
 173                  *      data_left > length, continue.
 174                  */
 175                 data_left -= length;
 176                 data += length - offset;
 177         }
 178
 179         /*
 180          *      We got this far.  It looks OK.
 181          */
 182         return 1;
 183 }
 184
 185
 186 /*
 187  *      Convert diameter attributes to our VALUE_PAIR's
 188  */
 189 static VALUE_PAIR *diameter2vp(SSL *ssl,
 190                                const uint8_t *data, unsigned int data_len)
 191 {
 192         uint32_t        attr;
 193         uint32_t        length;
 194         unsigned int    offset;
 195         int             size;
 196         unsigned int    data_left = data_len;
 197         VALUE_PAIR      *first = NULL;
 198         VALUE_PAIR      **last = &first;
 199         VALUE_PAIR      *vp;
 200
 201         while (data_left > 0) {
 202                 rad_assert(data_left <= data_len);
 203                 memcpy(&attr, data, sizeof(attr));
 204                 data += 4;
 205                 attr = ntohl(attr);
 206
 207                 memcpy(&length, data, sizeof(length));
 208                 data += 4;
 209                 length = ntohl(length);
 210
 211                 /*
 212                  *      FIXME: Handle the M bit!
 213                  *
 214                  *      Ignore the M bit.  We support all RADIUS attributes...
 215                  */
 216
 217                 /*
 218                  *      A "vendor" flag, with a vendor ID of zero,
 219                  *      is equivalent to no vendor.  This is stupid.
 220                  */
 221                 offset = 8;
 222                 if ((length & (1 << 31)) != 0) {
 223                         uint32_t vendor;
 224
 225                         memcpy(&vendor, data, sizeof(vendor));
 226                         vendor = ntohl(vendor);
 227
 228                         attr |= (vendor << 16);
 229
 230                         data += 4; /* skip the vendor field, it's zero */
 231                         offset += 4; /* offset to value field */
 232                 }
 233
 234                 /*
 235                  *      Get the length.
 236                  */
 237                 length &= 0x00ffffff;
 238
 239                 /*
 240                  *      Get the size of the value portion of the
 241                  *      attribute.
 242                  */
 243                 size = length - offset;
 244
 245                 /*
 246                  *      Create it.
 247                  */
 248                 vp = paircreate(attr, PW_TYPE_OCTETS);
 249                 if (!vp) {
 250                         DEBUG2("  rlm_eap_ttls: Failure in creating VP");
 251                         pairfree(&first);
 252                         return NULL;
 253                 }
 254
 255                 /*
 256                  *      If it's a type from our dictionary, then
 257                  *      we need to put the data in a relevant place.
 258                  */
 259                 switch (vp->type) {
 260                 case PW_TYPE_INTEGER:
 261                 case PW_TYPE_DATE:
 262                         if (size != vp->length) {
 263                                 DEBUG2("  rlm_eap_ttls: Invalid length attribute %d",
 264                                        attr);
 265                                 pairfree(&first);
 266                                 pairfree(&vp);
 267                                 return NULL;
 268                         }
 269                         memcpy(&vp->vp_integer, data, vp->length);
 270
 271                         /*
 272                          *      Stored in host byte order: change it.
 273                          */
 274                         vp->vp_integer = ntohl(vp->vp_integer);
 275                         break;
 276
 277                 case PW_TYPE_IPADDR:
 278                         if (size != vp->length) {
 279                                 DEBUG2("  rlm_eap_ttls: Invalid length attribute %d",
 280                                        attr);
 281                                 pairfree(&first);
 282                                 pairfree(&vp);
 283                                 return NULL;
 284                         }
 285                   memcpy(&vp->vp_ipaddr, data, vp->length);
 286
 287                   /*
 288                    *    Stored in network byte order: don't change it.
 289                    */
 290                   break;
 291
 292                   /*
 293                    *    String, octet, etc.  Copy the data from the
 294                    *    value field over verbatim.
 295                    *
 296                    *    FIXME: Ipv6 attributes ?
 297                    *
 298                    */
 299                 case PW_TYPE_OCTETS:
 300                         if (attr == PW_EAP_MESSAGE) {
 301                                 const uint8_t *eap_message = data;
 302
 303                                 /*
 304                                  *      vp exists the first time around.
 305                                  */
 306                                 while (1) {
 307                                         vp->length = size;
 308                                         if (vp->length > 253) vp->length = 253;
 309                                         memcpy(vp->vp_octets, eap_message,
 310                                                vp->length);
 311
 312                                         size -= vp->length;
 313                                         eap_message += vp->length;
 314
 315                                         *last = vp;
 316                                         last = &(vp->next);
 317
 318                                         if (size == 0) break;
 319
 320                                         vp = paircreate(attr, PW_TYPE_OCTETS);
 321                                         if (!vp) {
 322                                                 DEBUG2("  rlm_eap_ttls: Failure in creating VP");
 323                                                 pairfree(&first);
 324                                                 return NULL;
 325                                         }
 326                                 }
 327
 328                                 goto next_attr;
 329                         } /* else it's another kind of attribute */
 330                         /* FALL-THROUGH */
 331
 332                 default:
 333                         vp->length = size;
 334                         memcpy(vp->vp_strvalue, data, vp->length);
 335                         break;
 336                 }
 337
 338                 /*
 339                  *      User-Password is NUL padded to a multiple
 340                  *      of 16 bytes.  Let's chop it to something
 341                  *      more reasonable.
 342                  *
 343                  *      NOTE: This means that the User-Password
 344                  *      attribute CANNOT EVER have embedded zeros in it!
 345                  */
 346                 switch (vp->attribute) {
 347                 case PW_USER_PASSWORD:
 348                         /*
 349                          *      If the password is exactly 16 octets,
 350                          *      it won't be zero-terminated.
 351                          */
 352                         vp->vp_strvalue[vp->length] = '\0';
 353                         vp->length = strlen(vp->vp_strvalue);
 354                         break;
 355
 356                         /*
 357                          *      Ensure that the client is using the
 358                          *      correct challenge.  This weirdness is
 359                          *      to protect against against replay
 360                          *      attacks, where anyone observing the
 361                          *      CHAP exchange could pose as that user,
 362                          *      by simply choosing to use the same
 363                          *      challenge.
 364                          *
 365                          *      By using a challenge based on
 366                          *      information from the current session,
 367                          *      we can guarantee that the client is
 368                          *      not *choosing* a challenge.
 369                          *
 370                          *      We're a little forgiving in that we
 371                          *      have loose checks on the length, and
 372                          *      we do NOT check the Id (first octet of
 373                          *      the response to the challenge)
 374                          *
 375                          *      But if the client gets the challenge correct,
 376                          *      we're not too worried about the Id.
 377                          */
 378                 case PW_CHAP_CHALLENGE:
 379                 case PW_MSCHAP_CHALLENGE:
 380                         if ((vp->length < 8) ||
 381                             (vp->length > 16)) {
 382                                 DEBUG2("  TTLS: Tunneled challenge has invalid length");
 383                                 pairfree(&first);
 384                                 pairfree(&vp);
 385                                 return NULL;
 386
 387                         } else {
 388                                 uint8_t challenge[16];
 389
 390                                 eapttls_gen_challenge(ssl, challenge,
 391                                                       sizeof(challenge));
 392
 393                                 if (memcmp(challenge, vp->vp_octets,
 394                                            vp->length) != 0) {
 395                                         DEBUG2("  TTLS: Tunneled challenge is incorrect");
 396                                         pairfree(&first);
 397                                         pairfree(&vp);
 398                                         return NULL;
 399                                 }
 400                         }
 401                         break;
 402
 403                 default:
 404                         break;
 405                 } /* switch over checking/re-writing of attributes. */
 406
 407                 /*
 408                  *      Update the list.
 409                  */
 410                 *last = vp;
 411                 last = &(vp->next);
 412
 413         next_attr:
 414                 /*
 415                  *      Catch non-aligned attributes.
 416                  */
 417                 if (data_left == length) break;
 418
 419                 /*
 420                  *      The length does NOT include the padding, so
 421                  *      we've got to account for it here by rounding up
 422                  *      to the nearest 4-byte boundary.
 423                  */
 424                 length += 0x03;
 425                 length &= ~0x03;
 426
 427                 rad_assert(data_left >= length);
 428                 data_left -= length;
 429                 data += length - offset; /* already updated */
 430         }
 431
 432         /*
 433          *      We got this far.  It looks OK.
 434          */
 435         return first;
 436 }
 437
 438 /*
 439  *      Convert VALUE_PAIR's to diameter attributes, and write them
 440  *      to an SSL session.
 441  *
 442  *      The ONLY VALUE_PAIR's which may be passed to this function
 443  *      are ones which can go inside of a RADIUS (i.e. diameter)
 444  *      packet.  So no server-configuration attributes, or the like.
 445  */
 446 static int vp2diameter(tls_session_t *tls_session, VALUE_PAIR *first)
 447 {
 448         /*
 449          *      RADIUS packets are no more than 4k in size, so if
 450          *      we've got more than 4k of data to write, it's very
 451          *      bad.
 452          */
 453         uint8_t         buffer[4096];
 454         uint8_t         *p;
 455         uint32_t        attr;
 456         uint32_t        length;
 457         uint32_t        vendor;
 458         size_t          total;
 459         VALUE_PAIR      *vp;
 460
 461         p = buffer;
 462         total = 0;
 463
 464         for (vp = first; vp != NULL; vp = vp->next) {
 465                 /*
 466                  *      Too much data: die.
 467                  */
 468                 if ((total + vp->length + 12) >= sizeof(buffer)) {
 469                         DEBUG2("  TTLS output buffer is full!");
 470                         return 0;
 471                 }
 472
 473                 /*
 474                  *      Hmm... we don't group multiple EAP-Messages
 475                  *      together.  Maybe we should...
 476                  */
 477
 478                 /*
 479                  *      Length is no more than 253, due to RADIUS
 480                  *      issues.
 481                  */
 482                 length = vp->length;
 483                 vendor = (vp->attribute >> 16) & 0xffff;
 484                 if (vendor != 0) {
 485                         attr = vp->attribute & 0xffff;
 486                         length |= (1 << 31);
 487                 } else {
 488                         attr = vp->attribute;
 489                 }
 490
 491                 /*
 492                  *      Hmm... set the M bit for all attributes?
 493                  */
 494                 length |= (1 << 30);
 495
 496                 attr = ntohl(attr);
 497
 498                 memcpy(p, &attr, sizeof(attr));
 499                 p += 4;
 500                 total += 4;
 501
 502                 length += 8;    /* includes 8 bytes of attr & length */
 503
 504                 if (vendor != 0) {
 505                         length += 4; /* include 4 bytes of vendor */
 506
 507                         length = ntohl(length);
 508                         memcpy(p, &length, sizeof(length));
 509                         p += 4;
 510                         total += 4;
 511
 512                         vendor = ntohl(vendor);
 513                         memcpy(p, &vendor, sizeof(vendor));
 514                         p += 4;
 515                         total += 4;
 516                 } else {
 517                         length = ntohl(length);
 518                         memcpy(p, &length, sizeof(length));
 519                         p += 4;
 520                         total += 4;
 521                 }
 522
 523                 switch (vp->type) {
 524                 case PW_TYPE_INTEGER:
 525                 case PW_TYPE_DATE:
 526                         attr = ntohl(vp->vp_integer); /* stored in host order */
 527                         memcpy(p, &attr, sizeof(attr));
 528                         length = 4;
 529                         break;
 530
 531                 case PW_TYPE_IPADDR:
 532                         memcpy(p, &vp->vp_ipaddr, 4); /* network order */
 533                         length = 4;
 534                         break;
 535
 536                 case PW_TYPE_STRING:
 537                 case PW_TYPE_OCTETS:
 538                 default:
 539                         memcpy(p, vp->vp_strvalue, vp->length);
 540                         length = vp->length;
 541                         break;
 542                 }
 543
 544                 /*
 545                  *      Skip to the end of the data.
 546                  */
 547                 p += length;
 548                 total += length;
 549
 550                 /*
 551                  *      Align the data to a multiple of 4 bytes.
 552                  */
 553                 if ((total & 0x03) != 0) {
 554                         unsigned int i;
 555
 556                         length = 4 - (total & 0x03);
 557                         for (i = 0; i < length; i++) {
 558                                 *p = '\0';
 559                                 p++;
 560                                 total++;
 561                         }
 562                 }
 563         } /* loop over the VP's to write. */
 564
 565         /*
 566          *      Write the data in the buffer to the SSL session.
 567          */
 568         if (total > 0) {
 569 #ifndef NDEBUG
 570                 unsigned int i;
 571
 572                 if (debug_flag > 2) {
 573                         for (i = 0; i < total; i++) {
 574                                 if ((i & 0x0f) == 0) printf("  TTLS tunnel data out %04x: ", i);
 575
 576                                 printf("%02x ", buffer[i]);
 577
 578                                 if ((i & 0x0f) == 0x0f) printf("\n");
 579                         }
 580                         if ((total & 0x0f) != 0) printf("\n");
 581                 }
 582 #endif
 583
 584                 (tls_session->record_plus)(&tls_session->clean_in, buffer, total);
 585
 586                 /*
 587                  *      FIXME: Check the return code.
 588                  */
 589                 tls_handshake_send(tls_session);
 590         }
 591
 592         /*
 593          *      Everything's OK.
 594          */
 595         return 1;
 596 }
 597
 598 /*
 599  *      Use a reply packet to determine what to do.
 600  */
 601 static int process_reply(EAP_HANDLER *handler, tls_session_t *tls_session,
 602                          REQUEST *request, RADIUS_PACKET *reply)
 603 {
 604         int rcode = RLM_MODULE_REJECT;
 605         VALUE_PAIR *vp;
 606         ttls_tunnel_t *t = tls_session->opaque;
 607
 608         handler = handler;      /* -Wunused */
 609
 610         /*
 611          *      If the response packet was Access-Accept, then
 612          *      we're OK.  If not, die horribly.
 613          *
 614          *      FIXME: Take MS-CHAP2-Success attribute, and
 615          *      tunnel it back to the client, to authenticate
 616          *      ourselves to the client.
 617          *
 618          *      FIXME: If we have an Access-Challenge, then
 619          *      the Reply-Message is tunneled back to the client.
 620          *
 621          *      FIXME: If we have an EAP-Message, then that message
 622          *      must be tunneled back to the client.
 623          *
 624          *      FIXME: If we have an Access-Challenge with a State
 625          *      attribute, then do we tunnel that to the client, or
 626          *      keep track of it ourselves?
 627          *
 628          *      FIXME: EAP-Messages can only start with 'identity',
 629          *      NOT 'eap start', so we should check for that....
 630          */
 631         switch (reply->code) {
 632         case PW_AUTHENTICATION_ACK:
 633                 DEBUG2("  TTLS: Got tunneled Access-Accept");
 634
 635                 rcode = RLM_MODULE_OK;
 636
 637                 /*
 638                  *      MS-CHAP2-Success means that we do NOT return
 639                  *      an Access-Accept, but instead tunnel that
 640                  *      attribute to the client, and keep going with
 641                  *      the TTLS session.  Once the client accepts
 642                  *      our identity, it will respond with an empty
 643                  *      packet, and we will send EAP-Success.
 644                  */
 645                 vp = NULL;
 646                 pairmove2(&vp, &reply->vps, PW_MSCHAP2_SUCCESS);
 647                 if (vp) {
 648                         DEBUG2("  TTLS: Got MS-CHAP2-Success, tunneling it to the client in a challenge.");
 649                         rcode = RLM_MODULE_HANDLED;
 650                         t->authenticated = TRUE;
 651
 652                         /*
 653                          *      Delete MPPE keys & encryption policy.  We don't
 654                          *      want these here.
 655                          */
 656                         pairdelete(&reply->vps, ((311 << 16) | 7));
 657                         pairdelete(&reply->vps, ((311 << 16) | 8));
 658                         pairdelete(&reply->vps, ((311 << 16) | 16));
 659                         pairdelete(&reply->vps, ((311 << 16) | 17));
 660
 661                         /*
 662                          *      Use the tunneled reply, but not now.
 663                          */
 664                         if (t->use_tunneled_reply) {
 665                                 t->reply = reply->vps;
 666                                 reply->vps = NULL;
 667                         }
 668
 669                 } else { /* no MS-CHAP2-Success */
 670                         /*
 671                          *      Can only have EAP-Message if there's
 672                          *      no MS-CHAP2-Success.  (FIXME: EAP-MSCHAP?)
 673                          *
 674                          *      We also do NOT tunnel the EAP-Success
 675                          *      attribute back to the client, as the client
 676                          *      can figure it out, from the non-tunneled
 677                          *      EAP-Success packet.
 678                          */
 679                         pairmove2(&vp, &reply->vps, PW_EAP_MESSAGE);
 680                         pairfree(&vp);
 681                 }
 682
 683                 /*
 684                  *      Handle the ACK, by tunneling any necessary reply
 685                  *      VP's back to the client.
 686                  */
 687                 if (vp) {
 688                         vp2diameter(tls_session, vp);
 689                         pairfree(&vp);
 690                 }
 691
 692                 /*
 693                  *      If we've been told to use the attributes from
 694                  *      the reply, then do so.
 695                  *
 696                  *      WARNING: This may leak information about the
 697                  *      tunneled user!
 698                  */
 699                 if (t->use_tunneled_reply) {
 700                         pairdelete(&reply->vps, PW_PROXY_STATE);
 701                         pairadd(&request->reply->vps, reply->vps);
 702                         reply->vps = NULL;
 703                 }
 704                 break;
 705
 706
 707         case PW_AUTHENTICATION_REJECT:
 708                 DEBUG2("  TTLS: Got tunneled Access-Reject");
 709                 rcode = RLM_MODULE_REJECT;
 710                 break;
 711
 712                 /*
 713                  *      Handle Access-Challenge, but only if we
 714                  *      send tunneled reply data.  This is because
 715                  *      an Access-Challenge means that we MUST tunnel
 716                  *      a Reply-Message to the client.
 717                  */
 718         case PW_ACCESS_CHALLENGE:
 719                 DEBUG2("  TTLS: Got tunneled Access-Challenge");
 720
 721                 /*
 722                  *      Keep the State attribute, if necessary.
 723                  *
 724                  *      Get rid of the old State, too.
 725                  */
 726                 pairfree(&t->state);
 727                 pairmove2(&t->state, &reply->vps, PW_STATE);
 728
 729                 /*
 730                  *      We should really be a bit smarter about this,
 731                  *      and move over only those attributes which
 732                  *      are relevant to the authentication request,
 733                  *      but that's a lot more work, and this "dumb"
 734                  *      method works in 99.9% of the situations.
 735                  */
 736                 vp = NULL;
 737                 pairmove2(&vp, &reply->vps, PW_EAP_MESSAGE);
 738
 739                 /*
 740                  *      There MUST be a Reply-Message in the challenge,
 741                  *      which we tunnel back to the client.
 742                  *
 743                  *      If there isn't one in the reply VP's, then
 744                  *      we MUST create one, with an empty string as
 745                  *      it's value.
 746                  */
 747                 pairmove2(&vp, &reply->vps, PW_REPLY_MESSAGE);
 748
 749                 /*
 750                  *      Handle the ACK, by tunneling any necessary reply
 751                  *      VP's back to the client.
 752                  */
 753                 if (vp) {
 754                         vp2diameter(tls_session, vp);
 755                         pairfree(&vp);
 756                 }
 757                 rcode = RLM_MODULE_HANDLED;
 758                 break;
 759
 760         default:
 761                 DEBUG2("  TTLS: Unknown RADIUS packet type %d: rejecting tunneled user", reply->code);
 762                 rcode = RLM_MODULE_INVALID;
 763                 break;
 764         }
 765
 766         return rcode;
 767 }
 768
 769
 770 /*
 771  *      Do post-proxy processing,
 772  */
 773 static int eapttls_postproxy(EAP_HANDLER *handler, void *data)
 774 {
 775         int rcode;
 776         tls_session_t *tls_session = (tls_session_t *) data;
 777         REQUEST *fake;
 778
 779         DEBUG2("  TTLS: Passing reply from proxy back into the tunnel.");
 780
 781         /*
 782          *      If there was a fake request associated with the proxied
 783          *      request, do more processing of it.
 784          */
 785         fake = (REQUEST *) request_data_get(handler->request,
 786                                             handler->request->proxy,
 787                                             REQUEST_DATA_EAP_MSCHAP_TUNNEL_CALLBACK);
 788
 789         /*
 790          *      Do the callback, if it exists, and if it was a success.
 791          */
 792         if (fake && (handler->request->proxy_reply->code == PW_AUTHENTICATION_ACK)) {
 793                 VALUE_PAIR *vp;
 794                 REQUEST *request = handler->request;
 795
 796                 /*
 797                  *      Terrible hacks.
 798                  */
 799                 rad_assert(fake->packet == NULL);
 800                 fake->packet = request->proxy;
 801                 request->proxy = NULL;
 802
 803                 rad_assert(fake->reply == NULL);
 804                 fake->reply = request->proxy_reply;
 805                 request->proxy_reply = NULL;
 806
 807                 /*
 808                  *      Perform a post-auth stage for the tunneled
 809                  *      session.
 810                  */
 811                 fake->options &= ~RAD_REQUEST_OPTION_PROXY_EAP;
 812                 rcode = rad_postauth(fake);
 813                 DEBUG2("  POST-AUTH %d", rcode);
 814
 815 #ifndef NDEBUG
 816                 if (debug_flag > 0) {
 817                         printf("  TTLS: Final reply from tunneled session code %d\n",
 818                                fake->reply->code);
 819
 820                         for (vp = fake->reply->vps; vp != NULL; vp = vp->next) {
 821                                 putchar('\t');vp_print(stdout, vp);putchar('\n');
 822                         }
 823                 }
 824 #endif
 825
 826                 /*
 827                  *      Terrible hacks.
 828                  */
 829                 request->proxy = fake->packet;
 830                 fake->packet = NULL;
 831                 request->proxy_reply = fake->reply;
 832                 fake->reply = NULL;
 833
 834                 /*
 835                  *      And we're done with this request.
 836                  */
 837
 838                 switch (rcode) {
 839                 case RLM_MODULE_FAIL:
 840                         request_free(&fake);
 841                         eaptls_fail(handler->eap_ds, 0);
 842                         return 0;
 843                         break;
 844
 845                 default:  /* Don't Do Anything */
 846                         DEBUG2(" TTLS: Got reply %d",
 847                                request->proxy_reply->code);
 848                         break;
 849                 }
 850         }
 851         request_free(&fake);    /* robust if fake == NULL */
 852
 853         /*
 854          *      Process the reply from the home server.
 855          */
 856         rcode = process_reply(handler, tls_session, handler->request,
 857                               handler->request->proxy_reply);
 858
 859         /*
 860          *      The proxy code uses the reply from the home server as
 861          *      the basis for the reply to the NAS.  We don't want that,
 862          *      so we toss it, after we've had our way with it.
 863          */
 864         pairfree(&handler->request->proxy_reply->vps);
 865
 866         switch (rcode) {
 867         case RLM_MODULE_REJECT:
 868                 DEBUG2("  TTLS: Reply was rejected");
 869                 break;
 870
 871         case RLM_MODULE_HANDLED:
 872                 DEBUG2("  TTLS: Reply was handled");
 873                 eaptls_request(handler->eap_ds, tls_session);
 874                 return 1;
 875
 876         case RLM_MODULE_OK:
 877                 DEBUG2("  TTLS: Reply was OK");
 878                 eaptls_success(handler->eap_ds, 0);
 879                 eaptls_gen_mppe_keys(&handler->request->reply->vps,
 880                                      tls_session->ssl,
 881                                      "ttls keying material");
 882                 return 1;
 883
 884         default:
 885                 DEBUG2("  TTLS: Reply was unknown.");
 886                 break;
 887         }
 888
 889         eaptls_fail(handler->eap_ds, 0);
 890         return 0;
 891 }
 892
 893
 894 /*
 895  *      Free a request.
 896  */
 897 static void my_request_free(void *data)
 898 {
 899         REQUEST *request = (REQUEST *)data;
 900
 901         request_free(&request);
 902 }
 903
 904
 905 /*
 906  *      Process the "diameter" contents of the tunneled data.
 907  */
 908 int eapttls_process(EAP_HANDLER *handler, tls_session_t *tls_session)
 909 {
 910         int err;
 911         int rcode = PW_AUTHENTICATION_REJECT;
 912         REQUEST *fake;
 913         VALUE_PAIR *vp;
 914         ttls_tunnel_t *t;
 915         const uint8_t *data;
 916         unsigned int data_len;
 917         char buffer[1024];
 918         REQUEST *request = handler->request;
 919
 920         /*
 921          *      Grab the dirty data, and copy it to our buffer.
 922          *
 923          *      I *really* don't like these 'record_t' things...
 924          */
 925         data_len = (tls_session->record_minus)(&tls_session->dirty_in, buffer, sizeof(buffer));
 926         data = buffer;
 927
 928         /*
 929          *      Write the data from the dirty buffer (i.e. packet
 930          *      data) into the buffer which we will give to SSL for
 931          *      decoding.
 932          *
 933          *      Some of this code COULD technically go into the TLS
 934          *      module, in eaptls_process(), where it returns EAPTLS_OK.
 935          *
 936          *      Similarly, the writing of data to the SSL context could
 937          *      go there, too...
 938          */
 939         BIO_write(tls_session->into_ssl, buffer, data_len);
 940         (tls_session->record_init)(&tls_session->clean_out);
 941
 942         /*
 943          *      Read (and decrypt) the tunneled data from the SSL session,
 944          *      and put it into the decrypted data buffer.
 945          */
 946         err = SSL_read(tls_session->ssl, tls_session->clean_out.data,
 947                        sizeof(tls_session->clean_out.data));
 948         if (err < 0) {
 949                 /*
 950                  *      FIXME: Call SSL_get_error() to see what went
 951                  *      wrong.
 952                  */
 953                 radlog(L_INFO, "rlm_eap_ttls: SSL_read Error");
 954                 return PW_AUTHENTICATION_REJECT;
 955         }
 956
 957         t = (ttls_tunnel_t *) tls_session->opaque;
 958
 959         /*
 960          *      If there's no data, maybe this is an ACK to an
 961          *      MS-CHAP2-Success.
 962          */
 963         if (err == 0) {
 964                 if (t->authenticated) {
 965                         DEBUG2("  TTLS: Got ACK, and the user was already authenticated.");
 966                         return PW_AUTHENTICATION_ACK;
 967                 } /* else no session, no data, die. */
 968
 969                 /*
 970                  *      FIXME: Call SSL_get_error() to see what went
 971                  *      wrong.
 972                  */
 973                 radlog(L_INFO, "rlm_eap_ttls: SSL_read Error");
 974                 return PW_AUTHENTICATION_REJECT;
 975         }
 976
 977         data_len = tls_session->clean_out.used = err;
 978         data = tls_session->clean_out.data;
 979
 980 #ifndef NDEBUG
 981         if (debug_flag > 2) {
 982                 unsigned int i;
 983
 984                 for (i = 0; i < data_len; i++) {
 985                         if ((i & 0x0f) == 0) printf("  TTLS tunnel data in %04x: ", i);
 986
 987                         printf("%02x ", data[i]);
 988
 989                         if ((i & 0x0f) == 0x0f) printf("\n");
 990                 }
 991                 if ((data_len & 0x0f) != 0) printf("\n");
 992         }
 993 #endif
 994
 995         if (!diameter_verify(data, data_len)) {
 996                 return PW_AUTHENTICATION_REJECT;
 997         }
 998
 999         /*
1000          *      Allocate a fake REQUEST structe.
1001          */
1002         fake = request_alloc_fake(request);
1003
1004         rad_assert(fake->packet->vps == NULL);
1005
1006         /*
1007          *      Add the tunneled attributes to the fake request.
1008          */
1009         fake->packet->vps = diameter2vp(tls_session->ssl, data, data_len);
1010         if (!fake->packet->vps) {
1011                 request_free(&fake);
1012                 return PW_AUTHENTICATION_REJECT;
1013         }
1014
1015         /*
1016          *      Tell the request that it's a fake one.
1017          */
1018         vp = pairmake("Freeradius-Proxied-To", "127.0.0.1", T_OP_EQ);
1019         if (vp) {
1020                 pairadd(&fake->packet->vps, vp);
1021         }
1022
1023 #ifndef NDEBUG
1024         if (debug_flag > 0) {
1025                 printf("  TTLS: Got tunneled request\n");
1026
1027                 for (vp = fake->packet->vps; vp != NULL; vp = vp->next) {
1028                         putchar('\t');vp_print(stdout, vp);putchar('\n');
1029                 }
1030         }
1031 #endif
1032
1033         /*
1034          *      Update other items in the REQUEST data structure.
1035          */
1036         fake->username = pairfind(fake->packet->vps, PW_USER_NAME);
1037         fake->password = pairfind(fake->packet->vps, PW_USER_PASSWORD);
1038
1039         /*
1040          *      No User-Name, try to create one from stored data.
1041          */
1042         if (!fake->username) {
1043                 /*
1044                  *      No User-Name in the stored data, look for
1045                  *      an EAP-Identity, and pull it out of there.
1046                  */
1047                 if (!t->username) {
1048                         vp = pairfind(fake->packet->vps, PW_EAP_MESSAGE);
1049                         if (vp &&
1050                             (vp->length >= EAP_HEADER_LEN + 2) &&
1051                             (vp->vp_strvalue[0] == PW_EAP_RESPONSE) &&
1052                             (vp->vp_strvalue[EAP_HEADER_LEN] == PW_EAP_IDENTITY) &&
1053                             (vp->vp_strvalue[EAP_HEADER_LEN + 1] != 0)) {
1054                                 /*
1055                                  *      Create & remember a User-Name
1056                                  */
1057                                 t->username = pairmake("User-Name", "", T_OP_EQ);
1058                                 rad_assert(t->username != NULL);
1059
1060                                 memcpy(t->username->vp_strvalue, vp->vp_strvalue + 5,
1061                                        vp->length - 5);
1062                                 t->username->length = vp->length - 5;
1063                                 t->username->vp_strvalue[t->username->length] = 0;
1064
1065                                 DEBUG2("  TTLS: Got tunneled identity of %s",
1066                                        t->username->vp_strvalue);
1067
1068                                 /*
1069                                  *      If there's a default EAP type,
1070                                  *      set it here.
1071                                  */
1072                                 if (t->default_eap_type != 0) {
1073                                         DEBUG2("  TTLS: Setting default EAP type for tunneled EAP session.");
1074                                         vp = paircreate(PW_EAP_TYPE,
1075                                                         PW_TYPE_INTEGER);
1076                                         rad_assert(vp != NULL);
1077                                         vp->vp_integer = t->default_eap_type;
1078                                         pairadd(&fake->config_items, vp);
1079                                 }
1080
1081                         } else {
1082                                 /*
1083                                  *      Don't reject the request outright,
1084                                  *      as it's permitted to do EAP without
1085                                  *      user-name.
1086                                  */
1087                                 DEBUG2("  rlm_eap_ttls: WARNING! No EAP-Identity found to start EAP conversation.");
1088                         }
1089                 } /* else there WAS a t->username */
1090
1091                 if (t->username) {
1092                         vp = paircopy(t->username);
1093                         pairadd(&fake->packet->vps, vp);
1094                         fake->username = pairfind(fake->packet->vps, PW_USER_NAME);
1095                 }
1096         } /* else the request ALREADY had a User-Name */
1097
1098         /*
1099          *      Add the State attribute, too, if it exists.
1100          */
1101         if (t->state) {
1102                 DEBUG2("  TTLS: Adding old state with %02x %02x",
1103                        t->state->vp_strvalue[0], t->state->vp_strvalue[1]);
1104                 vp = paircopy(t->state);
1105                 if (vp) pairadd(&fake->packet->vps, vp);
1106         }
1107
1108         /*
1109          *      If this is set, we copy SOME of the request attributes
1110          *      from outside of the tunnel to inside of the tunnel.
1111          *
1112          *      We copy ONLY those attributes which do NOT already
1113          *      exist in the tunneled request.
1114          */
1115         if (t->copy_request_to_tunnel) {
1116                 VALUE_PAIR *copy;
1117
1118                 for (vp = request->packet->vps; vp != NULL; vp = vp->next) {
1119                         /*
1120                          *      The attribute is a server-side thingy,
1121                          *      don't copy it.
1122                          */
1123                         if ((vp->attribute > 255) &&
1124                             (((vp->attribute >> 16) & 0xffff) == 0)) {
1125                                 continue;
1126                         }
1127
1128                         /*
1129                          *      The outside attribute is already in the
1130                          *      tunnel, don't copy it.
1131                          *
1132                          *      This works for BOTH attributes which
1133                          *      are originally in the tunneled request,
1134                          *      AND attributes which are copied there
1135                          *      from below.
1136                          */
1137                         if (pairfind(fake->packet->vps, vp->attribute)) {
1138                                 continue;
1139                         }
1140
1141                         /*
1142                          *      Some attributes are handled specially.
1143                          */
1144                         switch (vp->attribute) {
1145                                 /*
1146                                  *      NEVER copy Message-Authenticator,
1147                                  *      EAP-Message, or State.  They're
1148                                  *      only for outside of the tunnel.
1149                                  */
1150                         case PW_USER_NAME:
1151                         case PW_USER_PASSWORD:
1152                         case PW_CHAP_PASSWORD:
1153                         case PW_CHAP_CHALLENGE:
1154                         case PW_PROXY_STATE:
1155                         case PW_MESSAGE_AUTHENTICATOR:
1156                         case PW_EAP_MESSAGE:
1157                         case PW_STATE:
1158                                 continue;
1159                                 break;
1160
1161                                 /*
1162                                  *      By default, copy it over.
1163                                  */
1164                         default:
1165                                 break;
1166                         }
1167
1168                         /*
1169                          *      Don't copy from the head, we've already
1170                          *      checked it.
1171                          */
1172                         copy = paircopy2(vp, vp->attribute);
1173                         pairadd(&fake->packet->vps, copy);
1174                 }
1175         }
1176
1177         if ((vp = pairfind(request->config_items, PW_VIRTUAL_SERVER)) != NULL) {
1178                 fake->server = vp->vp_strvalue;
1179
1180         } else if (t->virtual_server) {
1181                 fake->server = t->virtual_server;
1182
1183         } /* else fake->server == request->server */
1184
1185
1186 #ifndef NDEBUG
1187         if (debug_flag > 0) {
1188                 printf("  TTLS: Sending tunneled request\n");
1189
1190                 for (vp = fake->packet->vps; vp != NULL; vp = vp->next) {
1191                         putchar('\t');vp_print(stdout, vp);putchar('\n');
1192                 }
1193
1194                 printf("server %s {\n", fake->server);
1195         }
1196 #endif
1197
1198         /*
1199          *      Call authentication recursively, which will
1200          *      do PAP, CHAP, MS-CHAP, etc.
1201          */
1202         rad_authenticate(fake);
1203
1204         /*
1205          *      Note that we don't do *anything* with the reply
1206          *      attributes.
1207          */
1208 #ifndef NDEBUG
1209         if (debug_flag > 0) {
1210                 printf("} # server %s\n", fake->server);
1211
1212                 printf("  TTLS: Got tunneled reply RADIUS code %d\n",
1213                        fake->reply->code);
1214
1215                 for (vp = fake->reply->vps; vp != NULL; vp = vp->next) {
1216                         putchar('\t');vp_print(stdout, vp);putchar('\n');
1217                 }
1218         }
1219 #endif
1220
1221         /*
1222          *      Decide what to do with the reply.
1223          */
1224         switch (fake->reply->code) {
1225         case 0:                 /* No reply code, must be proxied... */
1226                 vp = pairfind(fake->config_items, PW_PROXY_TO_REALM);
1227                 if (vp) {
1228                         eap_tunnel_data_t *tunnel;
1229                         DEBUG2("  TTLS: Tunneled authentication will be proxied to %s", vp->vp_strvalue);
1230
1231                         /*
1232                          *      Tell the original request that it's going
1233                          *      to be proxied.
1234                          */
1235                         pairmove2(&(request->config_items),
1236                                   &(fake->config_items),
1237                                   PW_PROXY_TO_REALM);
1238
1239                         /*
1240                          *      Seed the proxy packet with the
1241                          *      tunneled request.
1242                          */
1243                         rad_assert(request->proxy == NULL);
1244                         request->proxy = fake->packet;
1245                         fake->packet = NULL;
1246                         rad_free(&fake->reply);
1247                         fake->reply = NULL;
1248
1249                         /*
1250                          *      Set up the callbacks for the tunnel
1251                          */
1252                         tunnel = rad_malloc(sizeof(*tunnel));
1253                         memset(tunnel, 0, sizeof(*tunnel));
1254
1255                         tunnel->tls_session = tls_session;
1256                         tunnel->callback = eapttls_postproxy;
1257
1258                         /*
1259                          *      Associate the callback with the request.
1260                          */
1261                         rcode = request_data_add(request,
1262                                                  request->proxy,
1263                                                  REQUEST_DATA_EAP_TUNNEL_CALLBACK,
1264                                                  tunnel, free);
1265                         rad_assert(rcode == 0);
1266
1267                         /*
1268                          *      rlm_eap.c has taken care of associating
1269                          *      the handler with the fake request.
1270                          *
1271                          *      So we associate the fake request with
1272                          *      this request.
1273                          */
1274                         rcode = request_data_add(request,
1275                                                  request->proxy,
1276                                                  REQUEST_DATA_EAP_MSCHAP_TUNNEL_CALLBACK,
1277                                                  fake, my_request_free);
1278                         rad_assert(rcode == 0);
1279                         fake = NULL;
1280
1281                         /*
1282                          *      Didn't authenticate the packet, but
1283                          *      we're proxying it.
1284                          */
1285                         rcode = PW_STATUS_CLIENT;
1286
1287                 } else {
1288                         DEBUG2("  TTLS: No tunneled reply was found for request %d , and the request was not proxied: rejecting the user.",
1289                                request->number);
1290                         rcode = PW_AUTHENTICATION_REJECT;
1291                 }
1292                 break;
1293
1294         default:
1295                 /*
1296                  *      Returns RLM_MODULE_FOO, and we want to return
1297                  *      PW_FOO
1298                  */
1299                 rcode = process_reply(handler, tls_session, request,
1300                                       fake->reply);
1301                 switch (rcode) {
1302                 case RLM_MODULE_REJECT:
1303                         rcode = PW_AUTHENTICATION_REJECT;
1304                         break;
1305
1306                 case RLM_MODULE_HANDLED:
1307                         rcode = PW_ACCESS_CHALLENGE;
1308                         break;
1309
1310                 case RLM_MODULE_OK:
1311                         rcode = PW_AUTHENTICATION_ACK;
1312                         break;
1313
1314                 default:
1315                         rcode = PW_AUTHENTICATION_REJECT;
1316                         break;
1317                 }
1318                 break;
1319         }
1320
1321         request_free(&fake);
1322
1323         return rcode;
1324 }