lib/liblwip/netif/ppp/chap.c

   1 /*** WARNING - THIS HAS NEVER BEEN FINISHED ***/
   2 /*****************************************************************************
   3 * chap.c - Network Challenge Handshake Authentication Protocol program file.
   4 *
   5 * Copyright (c) 2003 by Marc Boucher, Services Informatiques (MBSI) inc.
   6 * portions Copyright (c) 1997 by Global Election Systems Inc.
   7 *
   8 * The authors hereby grant permission to use, copy, modify, distribute,
   9 * and license this software and its documentation for any purpose, provided
  10 * that existing copyright notices are retained in all copies and that this
  11 * notice and the following disclaimer are included verbatim in any
  12 * distributions. No written agreement, license, or royalty fee is required
  13 * for any of the authorized uses.
  14 *
  15 * THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS *AS IS* AND ANY EXPRESS OR
  16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18 * IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25 *
  26 ******************************************************************************
  27 * REVISION HISTORY
  28 *
  29 * 03-01-01 Marc Boucher <marc@mbsi.ca>
  30 *   Ported to lwIP.
  31 * 97-12-04 Guy Lancaster <lancasterg@acm.org>, Global Election Systems Inc.
  32 *   Original based on BSD chap.c.
  33 *****************************************************************************/
  34 /*
  35  * chap.c - Challenge Handshake Authentication Protocol.
  36  *
  37  * Copyright (c) 1993 The Australian National University.
  38  * All rights reserved.
  39  *
  40  * Redistribution and use in source and binary forms are permitted
  41  * provided that the above copyright notice and this paragraph are
  42  * duplicated in all such forms and that any documentation,
  43  * advertising materials, and other materials related to such
  44  * distribution and use acknowledge that the software was developed
  45  * by the Australian National University.  The name of the University
  46  * may not be used to endorse or promote products derived from this
  47  * software without specific prior written permission.
  48  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  49  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  50  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  51  *
  52  * Copyright (c) 1991 Gregory M. Christy.
  53  * All rights reserved.
  54  *
  55  * Redistribution and use in source and binary forms are permitted
  56  * provided that the above copyright notice and this paragraph are
  57  * duplicated in all such forms and that any documentation,
  58  * advertising materials, and other materials related to such
  59  * distribution and use acknowledge that the software was developed
  60  * by Gregory M. Christy.  The name of the author may not be used to
  61  * endorse or promote products derived from this software without
  62  * specific prior written permission.
  63  *
  64  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  65  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  66  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  67  */
  68
  69 #include "lwip/opt.h"
  70
  71 #if PPP_SUPPORT  /* don't build if not configured for use in lwipopts.h */
  72
  73 #if CHAP_SUPPORT /* don't build if not configured for use in lwipopts.h */
  74
  75 #include "ppp.h"
  76 #include "pppdebug.h"
  77
  78 #include "magic.h"
  79 #include "randm.h"
  80 #include "auth.h"
  81 #include "md5.h"
  82 #include "chap.h"
  83 #include "chpms.h"
  84
  85 #include <string.h>
  86
  87 #if 0 /* UNUSED */
  88 /*
  89  * Command-line options.
  90  */
  91 static option_t chap_option_list[] = {
  92     { "chap-restart", o_int, &chap[0].timeouttime,
  93       "Set timeout for CHAP" },
  94     { "chap-max-challenge", o_int, &chap[0].max_transmits,
  95       "Set max #xmits for challenge" },
  96     { "chap-interval", o_int, &chap[0].chal_interval,
  97       "Set interval for rechallenge" },
  98 #ifdef MSLANMAN
  99     { "ms-lanman", o_bool, &ms_lanman,
 100       "Use LanMan passwd when using MS-CHAP", 1 },
 101 #endif
 102     { NULL }
 103 };
 104 #endif /* UNUSED */
 105
 106 /*
 107  * Protocol entry points.
 108  */
 109 static void ChapInit (int);
 110 static void ChapLowerUp (int);
 111 static void ChapLowerDown (int);
 112 static void ChapInput (int, u_char *, int);
 113 static void ChapProtocolReject (int);
 114 #if PPP_ADDITIONAL_CALLBACKS
 115 static int  ChapPrintPkt (u_char *, int, void (*) (void *, char *, ...), void *);
 116 #endif
 117
 118 struct protent chap_protent = {
 119   PPP_CHAP,
 120   ChapInit,
 121   ChapInput,
 122   ChapProtocolReject,
 123   ChapLowerUp,
 124   ChapLowerDown,
 125   NULL,
 126   NULL,
 127 #if PPP_ADDITIONAL_CALLBACKS
 128   ChapPrintPkt,
 129   NULL,
 130 #endif /* PPP_ADDITIONAL_CALLBACKS */
 131   1,
 132   "CHAP",
 133 #if PPP_ADDITIONAL_CALLBACKS
 134   NULL,
 135   NULL,
 136   NULL
 137 #endif /* PPP_ADDITIONAL_CALLBACKS */
 138 };
 139
 140 chap_state chap[NUM_PPP]; /* CHAP state; one for each unit */
 141
 142 static void ChapChallengeTimeout (void *);
 143 static void ChapResponseTimeout (void *);
 144 static void ChapReceiveChallenge (chap_state *, u_char *, u_char, int);
 145 static void ChapRechallenge (void *);
 146 static void ChapReceiveResponse (chap_state *, u_char *, int, int);
 147 static void ChapReceiveSuccess(chap_state *cstate, u_char *inp, u_char id, int len);
 148 static void ChapReceiveFailure(chap_state *cstate, u_char *inp, u_char id, int len);
 149 static void ChapSendStatus (chap_state *, int);
 150 static void ChapSendChallenge (chap_state *);
 151 static void ChapSendResponse (chap_state *);
 152 static void ChapGenChallenge (chap_state *);
 153
 154 /*
 155  * ChapInit - Initialize a CHAP unit.
 156  */
 157 static void
 158 ChapInit(int unit)
 159 {
 160   chap_state *cstate = &chap[unit];
 161
 162   BZERO(cstate, sizeof(*cstate));
 163   cstate->unit = unit;
 164   cstate->clientstate = CHAPCS_INITIAL;
 165   cstate->serverstate = CHAPSS_INITIAL;
 166   cstate->timeouttime = CHAP_DEFTIMEOUT;
 167   cstate->max_transmits = CHAP_DEFTRANSMITS;
 168   /* random number generator is initialized in magic_init */
 169 }
 170
 171
 172 /*
 173  * ChapAuthWithPeer - Authenticate us with our peer (start client).
 174  *
 175  */
 176 void
 177 ChapAuthWithPeer(int unit, char *our_name, u_char digest)
 178 {
 179   chap_state *cstate = &chap[unit];
 180
 181   cstate->resp_name = our_name;
 182   cstate->resp_type = digest;
 183
 184   if (cstate->clientstate == CHAPCS_INITIAL ||
 185       cstate->clientstate == CHAPCS_PENDING) {
 186     /* lower layer isn't up - wait until later */
 187     cstate->clientstate = CHAPCS_PENDING;
 188     return;
 189   }
 190
 191   /*
 192    * We get here as a result of LCP coming up.
 193    * So even if CHAP was open before, we will
 194    * have to re-authenticate ourselves.
 195    */
 196   cstate->clientstate = CHAPCS_LISTEN;
 197 }
 198
 199
 200 /*
 201  * ChapAuthPeer - Authenticate our peer (start server).
 202  */
 203 void
 204 ChapAuthPeer(int unit, char *our_name, u_char digest)
 205 {
 206   chap_state *cstate = &chap[unit];
 207
 208   cstate->chal_name = our_name;
 209   cstate->chal_type = digest;
 210
 211   if (cstate->serverstate == CHAPSS_INITIAL ||
 212       cstate->serverstate == CHAPSS_PENDING) {
 213     /* lower layer isn't up - wait until later */
 214     cstate->serverstate = CHAPSS_PENDING;
 215     return;
 216   }
 217
 218   ChapGenChallenge(cstate);
 219   ChapSendChallenge(cstate);    /* crank it up dude! */
 220   cstate->serverstate = CHAPSS_INITIAL_CHAL;
 221 }
 222
 223
 224 /*
 225  * ChapChallengeTimeout - Timeout expired on sending challenge.
 226  */
 227 static void
 228 ChapChallengeTimeout(void *arg)
 229 {
 230   chap_state *cstate = (chap_state *) arg;
 231
 232   /* if we aren't sending challenges, don't worry.  then again we */
 233   /* probably shouldn't be here either */
 234   if (cstate->serverstate != CHAPSS_INITIAL_CHAL &&
 235       cstate->serverstate != CHAPSS_RECHALLENGE) {
 236     return;
 237   }
 238
 239   if (cstate->chal_transmits >= cstate->max_transmits) {
 240     /* give up on peer */
 241     CHAPDEBUG(LOG_ERR, ("Peer failed to respond to CHAP challenge\n"));
 242     cstate->serverstate = CHAPSS_BADAUTH;
 243     auth_peer_fail(cstate->unit, PPP_CHAP);
 244     return;
 245   }
 246
 247   ChapSendChallenge(cstate); /* Re-send challenge */
 248 }
 249
 250
 251 /*
 252  * ChapResponseTimeout - Timeout expired on sending response.
 253  */
 254 static void
 255 ChapResponseTimeout(void *arg)
 256 {
 257   chap_state *cstate = (chap_state *) arg;
 258
 259   /* if we aren't sending a response, don't worry. */
 260   if (cstate->clientstate != CHAPCS_RESPONSE) {
 261     return;
 262   }
 263
 264   ChapSendResponse(cstate);    /* re-send response */
 265 }
 266
 267
 268 /*
 269  * ChapRechallenge - Time to challenge the peer again.
 270  */
 271 static void
 272 ChapRechallenge(void *arg)
 273 {
 274   chap_state *cstate = (chap_state *) arg;
 275
 276   /* if we aren't sending a response, don't worry. */
 277   if (cstate->serverstate != CHAPSS_OPEN) {
 278     return;
 279   }
 280
 281   ChapGenChallenge(cstate);
 282   ChapSendChallenge(cstate);
 283   cstate->serverstate = CHAPSS_RECHALLENGE;
 284 }
 285
 286
 287 /*
 288  * ChapLowerUp - The lower layer is up.
 289  *
 290  * Start up if we have pending requests.
 291  */
 292 static void
 293 ChapLowerUp(int unit)
 294 {
 295   chap_state *cstate = &chap[unit];
 296
 297   if (cstate->clientstate == CHAPCS_INITIAL) {
 298     cstate->clientstate = CHAPCS_CLOSED;
 299   } else if (cstate->clientstate == CHAPCS_PENDING) {
 300     cstate->clientstate = CHAPCS_LISTEN;
 301   }
 302
 303   if (cstate->serverstate == CHAPSS_INITIAL) {
 304     cstate->serverstate = CHAPSS_CLOSED;
 305   } else if (cstate->serverstate == CHAPSS_PENDING) {
 306     ChapGenChallenge(cstate);
 307     ChapSendChallenge(cstate);
 308     cstate->serverstate = CHAPSS_INITIAL_CHAL;
 309   }
 310 }
 311
 312
 313 /*
 314  * ChapLowerDown - The lower layer is down.
 315  *
 316  * Cancel all timeouts.
 317  */
 318 static void
 319 ChapLowerDown(int unit)
 320 {
 321   chap_state *cstate = &chap[unit];
 322
 323   /* Timeout(s) pending?  Cancel if so. */
 324   if (cstate->serverstate == CHAPSS_INITIAL_CHAL ||
 325       cstate->serverstate == CHAPSS_RECHALLENGE) {
 326     UNTIMEOUT(ChapChallengeTimeout, cstate);
 327   } else if (cstate->serverstate == CHAPSS_OPEN
 328       && cstate->chal_interval != 0) {
 329     UNTIMEOUT(ChapRechallenge, cstate);
 330   }
 331   if (cstate->clientstate == CHAPCS_RESPONSE) {
 332     UNTIMEOUT(ChapResponseTimeout, cstate);
 333   }
 334   cstate->clientstate = CHAPCS_INITIAL;
 335   cstate->serverstate = CHAPSS_INITIAL;
 336 }
 337
 338
 339 /*
 340  * ChapProtocolReject - Peer doesn't grok CHAP.
 341  */
 342 static void
 343 ChapProtocolReject(int unit)
 344 {
 345   chap_state *cstate = &chap[unit];
 346
 347   if (cstate->serverstate != CHAPSS_INITIAL &&
 348       cstate->serverstate != CHAPSS_CLOSED) {
 349     auth_peer_fail(unit, PPP_CHAP);
 350   }
 351   if (cstate->clientstate != CHAPCS_INITIAL &&
 352       cstate->clientstate != CHAPCS_CLOSED) {
 353     auth_withpeer_fail(unit, PPP_CHAP); /* lwip: just sets the PPP error code on this unit to PPPERR_AUTHFAIL */
 354   }
 355   ChapLowerDown(unit); /* shutdown chap */
 356 }
 357
 358
 359 /*
 360  * ChapInput - Input CHAP packet.
 361  */
 362 static void
 363 ChapInput(int unit, u_char *inpacket, int packet_len)
 364 {
 365   chap_state *cstate = &chap[unit];
 366   u_char *inp;
 367   u_char code, id;
 368   int len;
 369
 370   /*
 371    * Parse header (code, id and length).
 372    * If packet too short, drop it.
 373    */
 374   inp = inpacket;
 375   if (packet_len < CHAP_HEADERLEN) {
 376     CHAPDEBUG(LOG_INFO, ("ChapInput: rcvd short header.\n"));
 377     return;
 378   }
 379   GETCHAR(code, inp);
 380   GETCHAR(id, inp);
 381   GETSHORT(len, inp);
 382   if (len < CHAP_HEADERLEN) {
 383     CHAPDEBUG(LOG_INFO, ("ChapInput: rcvd illegal length.\n"));
 384     return;
 385   }
 386   if (len > packet_len) {
 387     CHAPDEBUG(LOG_INFO, ("ChapInput: rcvd short packet.\n"));
 388     return;
 389   }
 390   len -= CHAP_HEADERLEN;
 391
 392   /*
 393    * Action depends on code (as in fact it usually does :-).
 394    */
 395   switch (code) {
 396     case CHAP_CHALLENGE:
 397       ChapReceiveChallenge(cstate, inp, id, len);
 398       break;
 399
 400     case CHAP_RESPONSE:
 401       ChapReceiveResponse(cstate, inp, id, len);
 402       break;
 403
 404     case CHAP_FAILURE:
 405       ChapReceiveFailure(cstate, inp, id, len);
 406       break;
 407
 408     case CHAP_SUCCESS:
 409       ChapReceiveSuccess(cstate, inp, id, len);
 410       break;
 411
 412     default:        /* Need code reject? */
 413       CHAPDEBUG(LOG_WARNING, ("Unknown CHAP code (%d) received.\n", code));
 414       break;
 415   }
 416 }
 417
 418
 419 /*
 420  * ChapReceiveChallenge - Receive Challenge and send Response.
 421  */
 422 static void
 423 ChapReceiveChallenge(chap_state *cstate, u_char *inp, u_char id, int len)
 424 {
 425   int rchallenge_len;
 426   u_char *rchallenge;
 427   int secret_len;
 428   char secret[MAXSECRETLEN];
 429   char rhostname[256];
 430   MD5_CTX mdContext;
 431   u_char hash[MD5_SIGNATURE_SIZE];
 432
 433   CHAPDEBUG(LOG_INFO, ("ChapReceiveChallenge: Rcvd id %d.\n", id));
 434   if (cstate->clientstate == CHAPCS_CLOSED ||
 435     cstate->clientstate == CHAPCS_PENDING) {
 436     CHAPDEBUG(LOG_INFO, ("ChapReceiveChallenge: in state %d\n",
 437          cstate->clientstate));
 438     return;
 439   }
 440
 441   if (len < 2) {
 442     CHAPDEBUG(LOG_INFO, ("ChapReceiveChallenge: rcvd short packet.\n"));
 443     return;
 444   }
 445
 446   GETCHAR(rchallenge_len, inp);
 447   len -= sizeof (u_char) + rchallenge_len;  /* now name field length */
 448   if (len < 0) {
 449     CHAPDEBUG(LOG_INFO, ("ChapReceiveChallenge: rcvd short packet.\n"));
 450     return;
 451   }
 452   rchallenge = inp;
 453   INCPTR(rchallenge_len, inp);
 454
 455   if (len >= (int)sizeof(rhostname)) {
 456     len = sizeof(rhostname) - 1;
 457   }
 458   BCOPY(inp, rhostname, len);
 459   rhostname[len] = '\000';
 460
 461   CHAPDEBUG(LOG_INFO, ("ChapReceiveChallenge: received name field '%s'\n",
 462              rhostname));
 463
 464   /* Microsoft doesn't send their name back in the PPP packet */
 465   if (ppp_settings.remote_name[0] != 0 && (ppp_settings.explicit_remote || rhostname[0] == 0)) {
 466     strncpy(rhostname, ppp_settings.remote_name, sizeof(rhostname));
 467     rhostname[sizeof(rhostname) - 1] = 0;
 468     CHAPDEBUG(LOG_INFO, ("ChapReceiveChallenge: using '%s' as remote name\n",
 469                rhostname));
 470   }
 471
 472   /* get secret for authenticating ourselves with the specified host */
 473   if (!get_secret(cstate->unit, cstate->resp_name, rhostname,
 474                   secret, &secret_len, 0)) {
 475     secret_len = 0;    /* assume null secret if can't find one */
 476     CHAPDEBUG(LOG_WARNING, ("No CHAP secret found for authenticating us to %s\n",
 477                rhostname));
 478   }
 479
 480   /* cancel response send timeout if necessary */
 481   if (cstate->clientstate == CHAPCS_RESPONSE) {
 482     UNTIMEOUT(ChapResponseTimeout, cstate);
 483   }
 484
 485   cstate->resp_id = id;
 486   cstate->resp_transmits = 0;
 487
 488   /*  generate MD based on negotiated type */
 489   switch (cstate->resp_type) {
 490
 491   case CHAP_DIGEST_MD5:
 492     MD5Init(&mdContext);
 493     MD5Update(&mdContext, &cstate->resp_id, 1);
 494     MD5Update(&mdContext, (u_char*)secret, secret_len);
 495     MD5Update(&mdContext, rchallenge, rchallenge_len);
 496     MD5Final(hash, &mdContext);
 497     BCOPY(hash, cstate->response, MD5_SIGNATURE_SIZE);
 498     cstate->resp_length = MD5_SIGNATURE_SIZE;
 499     break;
 500
 501 #if MSCHAP_SUPPORT
 502   case CHAP_MICROSOFT:
 503     ChapMS(cstate, rchallenge, rchallenge_len, secret, secret_len);
 504     break;
 505 #endif
 506
 507   default:
 508     CHAPDEBUG(LOG_INFO, ("unknown digest type %d\n", cstate->resp_type));
 509     return;
 510   }
 511
 512   BZERO(secret, sizeof(secret));
 513   ChapSendResponse(cstate);
 514 }
 515
 516
 517 /*
 518  * ChapReceiveResponse - Receive and process response.
 519  */
 520 static void
 521 ChapReceiveResponse(chap_state *cstate, u_char *inp, int id, int len)
 522 {
 523   u_char *remmd, remmd_len;
 524   int secret_len, old_state;
 525   int code;
 526   char rhostname[256];
 527   MD5_CTX mdContext;
 528   char secret[MAXSECRETLEN];
 529   u_char hash[MD5_SIGNATURE_SIZE];
 530
 531   CHAPDEBUG(LOG_INFO, ("ChapReceiveResponse: Rcvd id %d.\n", id));
 532
 533   if (cstate->serverstate == CHAPSS_CLOSED ||
 534       cstate->serverstate == CHAPSS_PENDING) {
 535     CHAPDEBUG(LOG_INFO, ("ChapReceiveResponse: in state %d\n",
 536     cstate->serverstate));
 537     return;
 538   }
 539
 540   if (id != cstate->chal_id) {
 541     return;      /* doesn't match ID of last challenge */
 542   }
 543
 544   /*
 545   * If we have received a duplicate or bogus Response,
 546   * we have to send the same answer (Success/Failure)
 547   * as we did for the first Response we saw.
 548   */
 549   if (cstate->serverstate == CHAPSS_OPEN) {
 550     ChapSendStatus(cstate, CHAP_SUCCESS);
 551     return;
 552   }
 553   if (cstate->serverstate == CHAPSS_BADAUTH) {
 554     ChapSendStatus(cstate, CHAP_FAILURE);
 555     return;
 556   }
 557
 558   if (len < 2) {
 559     CHAPDEBUG(LOG_INFO, ("ChapReceiveResponse: rcvd short packet.\n"));
 560     return;
 561   }
 562   GETCHAR(remmd_len, inp); /* get length of MD */
 563   remmd = inp;             /* get pointer to MD */
 564   INCPTR(remmd_len, inp);
 565
 566   len -= sizeof (u_char) + remmd_len;
 567   if (len < 0) {
 568     CHAPDEBUG(LOG_INFO, ("ChapReceiveResponse: rcvd short packet.\n"));
 569     return;
 570   }
 571
 572   UNTIMEOUT(ChapChallengeTimeout, cstate);
 573
 574   if (len >= (int)sizeof(rhostname)) {
 575     len = sizeof(rhostname) - 1;
 576   }
 577   BCOPY(inp, rhostname, len);
 578   rhostname[len] = '\000';
 579
 580   CHAPDEBUG(LOG_INFO, ("ChapReceiveResponse: received name field: %s\n",
 581              rhostname));
 582
 583   /*
 584   * Get secret for authenticating them with us,
 585   * do the hash ourselves, and compare the result.
 586   */
 587   code = CHAP_FAILURE;
 588   if (!get_secret(cstate->unit, rhostname, cstate->chal_name,
 589                   secret, &secret_len, 1)) {
 590     CHAPDEBUG(LOG_WARNING, ("No CHAP secret found for authenticating %s\n",
 591                rhostname));
 592   } else {
 593     /*  generate MD based on negotiated type */
 594     switch (cstate->chal_type) {
 595
 596       case CHAP_DIGEST_MD5:    /* only MD5 is defined for now */
 597         if (remmd_len != MD5_SIGNATURE_SIZE) {
 598           break;      /* it's not even the right length */
 599         }
 600         MD5Init(&mdContext);
 601         MD5Update(&mdContext, &cstate->chal_id, 1);
 602         MD5Update(&mdContext, (u_char*)secret, secret_len);
 603         MD5Update(&mdContext, cstate->challenge, cstate->chal_len);
 604         MD5Final(hash, &mdContext);
 605
 606         /* compare local and remote MDs and send the appropriate status */
 607         if (memcmp (hash, remmd, MD5_SIGNATURE_SIZE) == 0) {
 608           code = CHAP_SUCCESS;  /* they are the same! */
 609         }
 610         break;
 611
 612       default:
 613         CHAPDEBUG(LOG_INFO, ("unknown digest type %d\n", cstate->chal_type));
 614     }
 615   }
 616
 617   BZERO(secret, sizeof(secret));
 618   ChapSendStatus(cstate, code);
 619
 620   if (code == CHAP_SUCCESS) {
 621     old_state = cstate->serverstate;
 622     cstate->serverstate = CHAPSS_OPEN;
 623     if (old_state == CHAPSS_INITIAL_CHAL) {
 624       auth_peer_success(cstate->unit, PPP_CHAP, rhostname, len);
 625     }
 626     if (cstate->chal_interval != 0) {
 627       TIMEOUT(ChapRechallenge, cstate, cstate->chal_interval);
 628     }
 629   } else {
 630     CHAPDEBUG(LOG_ERR, ("CHAP peer authentication failed\n"));
 631     cstate->serverstate = CHAPSS_BADAUTH;
 632     auth_peer_fail(cstate->unit, PPP_CHAP);
 633   }
 634 }
 635
 636 /*
 637  * ChapReceiveSuccess - Receive Success
 638  */
 639 static void
 640 ChapReceiveSuccess(chap_state *cstate, u_char *inp, u_char id, int len)
 641 {
 642   LWIP_UNUSED_ARG(id);
 643   LWIP_UNUSED_ARG(inp);
 644
 645   CHAPDEBUG(LOG_INFO, ("ChapReceiveSuccess: Rcvd id %d.\n", id));
 646
 647   if (cstate->clientstate == CHAPCS_OPEN) {
 648     /* presumably an answer to a duplicate response */
 649     return;
 650   }
 651
 652   if (cstate->clientstate != CHAPCS_RESPONSE) {
 653     /* don't know what this is */
 654     CHAPDEBUG(LOG_INFO, ("ChapReceiveSuccess: in state %d\n",
 655                cstate->clientstate));
 656     return;
 657   }
 658
 659   UNTIMEOUT(ChapResponseTimeout, cstate);
 660
 661   /*
 662    * Print message.
 663    */
 664   if (len > 0) {
 665     PRINTMSG(inp, len);
 666   }
 667
 668   cstate->clientstate = CHAPCS_OPEN;
 669
 670   auth_withpeer_success(cstate->unit, PPP_CHAP);
 671 }
 672
 673
 674 /*
 675  * ChapReceiveFailure - Receive failure.
 676  */
 677 static void
 678 ChapReceiveFailure(chap_state *cstate, u_char *inp, u_char id, int len)
 679 {
 680   LWIP_UNUSED_ARG(id);
 681   LWIP_UNUSED_ARG(inp);
 682
 683   CHAPDEBUG(LOG_INFO, ("ChapReceiveFailure: Rcvd id %d.\n", id));
 684
 685   if (cstate->clientstate != CHAPCS_RESPONSE) {
 686     /* don't know what this is */
 687     CHAPDEBUG(LOG_INFO, ("ChapReceiveFailure: in state %d\n",
 688                cstate->clientstate));
 689     return;
 690   }
 691
 692   UNTIMEOUT(ChapResponseTimeout, cstate);
 693
 694   /*
 695    * Print message.
 696    */
 697   if (len > 0) {
 698     PRINTMSG(inp, len);
 699   }
 700
 701   CHAPDEBUG(LOG_ERR, ("CHAP authentication failed\n"));
 702   auth_withpeer_fail(cstate->unit, PPP_CHAP); /* lwip: just sets the PPP error code on this unit to PPPERR_AUTHFAIL */
 703 }
 704
 705
 706 /*
 707  * ChapSendChallenge - Send an Authenticate challenge.
 708  */
 709 static void
 710 ChapSendChallenge(chap_state *cstate)
 711 {
 712   u_char *outp;
 713   int chal_len, name_len;
 714   int outlen;
 715
 716   chal_len = cstate->chal_len;
 717   name_len = (int)strlen(cstate->chal_name);
 718   outlen = CHAP_HEADERLEN + sizeof (u_char) + chal_len + name_len;
 719   outp = outpacket_buf[cstate->unit];
 720
 721   MAKEHEADER(outp, PPP_CHAP);    /* paste in a CHAP header */
 722
 723   PUTCHAR(CHAP_CHALLENGE, outp);
 724   PUTCHAR(cstate->chal_id, outp);
 725   PUTSHORT(outlen, outp);
 726
 727   PUTCHAR(chal_len, outp);    /* put length of challenge */
 728   BCOPY(cstate->challenge, outp, chal_len);
 729   INCPTR(chal_len, outp);
 730
 731   BCOPY(cstate->chal_name, outp, name_len);  /* append hostname */
 732
 733   pppWrite(cstate->unit, outpacket_buf[cstate->unit], outlen + PPP_HDRLEN);
 734
 735   CHAPDEBUG(LOG_INFO, ("ChapSendChallenge: Sent id %d.\n", cstate->chal_id));
 736
 737   TIMEOUT(ChapChallengeTimeout, cstate, cstate->timeouttime);
 738   ++cstate->chal_transmits;
 739 }
 740
 741
 742 /*
 743  * ChapSendStatus - Send a status response (ack or nak).
 744  */
 745 static void
 746 ChapSendStatus(chap_state *cstate, int code)
 747 {
 748   u_char *outp;
 749   int outlen, msglen;
 750   char msg[256]; /* @todo: this can be a char*, no strcpy needed */
 751
 752   if (code == CHAP_SUCCESS) {
 753     strcpy(msg, "Welcome!");
 754   } else {
 755     strcpy(msg, "I don't like you.  Go 'way.");
 756   }
 757   msglen = (int)strlen(msg);
 758
 759   outlen = CHAP_HEADERLEN + msglen;
 760   outp = outpacket_buf[cstate->unit];
 761
 762   MAKEHEADER(outp, PPP_CHAP);    /* paste in a header */
 763
 764   PUTCHAR(code, outp);
 765   PUTCHAR(cstate->chal_id, outp);
 766   PUTSHORT(outlen, outp);
 767   BCOPY(msg, outp, msglen);
 768   pppWrite(cstate->unit, outpacket_buf[cstate->unit], outlen + PPP_HDRLEN);
 769
 770   CHAPDEBUG(LOG_INFO, ("ChapSendStatus: Sent code %d, id %d.\n", code,
 771              cstate->chal_id));
 772 }
 773
 774 /*
 775  * ChapGenChallenge is used to generate a pseudo-random challenge string of
 776  * a pseudo-random length between min_len and max_len.  The challenge
 777  * string and its length are stored in *cstate, and various other fields of
 778  * *cstate are initialized.
 779  */
 780
 781 static void
 782 ChapGenChallenge(chap_state *cstate)
 783 {
 784   int chal_len;
 785   u_char *ptr = cstate->challenge;
 786   int i;
 787
 788   /* pick a random challenge length between MIN_CHALLENGE_LENGTH and
 789      MAX_CHALLENGE_LENGTH */
 790   chal_len = (unsigned)
 791         ((((magic() >> 16) *
 792               (MAX_CHALLENGE_LENGTH - MIN_CHALLENGE_LENGTH)) >> 16)
 793            + MIN_CHALLENGE_LENGTH);
 794   LWIP_ASSERT("chal_len <= 0xff", chal_len <= 0xffff);
 795   cstate->chal_len = (u_char)chal_len;
 796   cstate->chal_id = ++cstate->id;
 797   cstate->chal_transmits = 0;
 798
 799   /* generate a random string */
 800   for (i = 0; i < chal_len; i++ ) {
 801     *ptr++ = (char) (magic() & 0xff);
 802   }
 803 }
 804
 805 /*
 806  * ChapSendResponse - send a response packet with values as specified
 807  * in *cstate.
 808  */
 809 /* ARGSUSED */
 810 static void
 811 ChapSendResponse(chap_state *cstate)
 812 {
 813   u_char *outp;
 814   int outlen, md_len, name_len;
 815
 816   md_len = cstate->resp_length;
 817   name_len = (int)strlen(cstate->resp_name);
 818   outlen = CHAP_HEADERLEN + sizeof (u_char) + md_len + name_len;
 819   outp = outpacket_buf[cstate->unit];
 820
 821   MAKEHEADER(outp, PPP_CHAP);
 822
 823   PUTCHAR(CHAP_RESPONSE, outp);  /* we are a response */
 824   PUTCHAR(cstate->resp_id, outp);  /* copy id from challenge packet */
 825   PUTSHORT(outlen, outp);      /* packet length */
 826
 827   PUTCHAR(md_len, outp);      /* length of MD */
 828   BCOPY(cstate->response, outp, md_len);    /* copy MD to buffer */
 829   INCPTR(md_len, outp);
 830
 831   BCOPY(cstate->resp_name, outp, name_len);  /* append our name */
 832
 833   /* send the packet */
 834   pppWrite(cstate->unit, outpacket_buf[cstate->unit], outlen + PPP_HDRLEN);
 835
 836   cstate->clientstate = CHAPCS_RESPONSE;
 837   TIMEOUT(ChapResponseTimeout, cstate, cstate->timeouttime);
 838   ++cstate->resp_transmits;
 839 }
 840
 841 #if PPP_ADDITIONAL_CALLBACKS
 842 static char *ChapCodenames[] = {
 843   "Challenge", "Response", "Success", "Failure"
 844 };
 845 /*
 846  * ChapPrintPkt - print the contents of a CHAP packet.
 847  */
 848 static int
 849 ChapPrintPkt( u_char *p, int plen, void (*printer) (void *, char *, ...), void *arg)
 850 {
 851   int code, id, len;
 852   int clen, nlen;
 853   u_char x;
 854
 855   if (plen < CHAP_HEADERLEN) {
 856     return 0;
 857   }
 858   GETCHAR(code, p);
 859   GETCHAR(id, p);
 860   GETSHORT(len, p);
 861   if (len < CHAP_HEADERLEN || len > plen) {
 862     return 0;
 863   }
 864
 865   if (code >= 1 && code <= sizeof(ChapCodenames) / sizeof(char *)) {
 866     printer(arg, " %s", ChapCodenames[code-1]);
 867   } else {
 868     printer(arg, " code=0x%x", code);
 869   }
 870   printer(arg, " id=0x%x", id);
 871   len -= CHAP_HEADERLEN;
 872   switch (code) {
 873     case CHAP_CHALLENGE:
 874     case CHAP_RESPONSE:
 875       if (len < 1) {
 876         break;
 877       }
 878       clen = p[0];
 879       if (len < clen + 1) {
 880         break;
 881       }
 882       ++p;
 883       nlen = len - clen - 1;
 884       printer(arg, " <");
 885       for (; clen > 0; --clen) {
 886         GETCHAR(x, p);
 887         printer(arg, "%.2x", x);
 888       }
 889       printer(arg, ">, name = %.*Z", nlen, p);
 890       break;
 891     case CHAP_FAILURE:
 892     case CHAP_SUCCESS:
 893       printer(arg, " %.*Z", len, p);
 894       break;
 895     default:
 896       for (clen = len; clen > 0; --clen) {
 897         GETCHAR(x, p);
 898         printer(arg, " %.2x", x);
 899       }
 900   }
 901
 902   return len + CHAP_HEADERLEN;
 903 }
 904 #endif /* PPP_ADDITIONAL_CALLBACKS */
 905
 906 #endif /* CHAP_SUPPORT */
 907
 908 #endif /* PPP_SUPPORT */