release/src/router/ppp/pppd/chap.c

   1 /*
   2  * chap.c - Challenge Handshake Authentication Protocol.
   3  *
   4  * Copyright (c) 1993 The Australian National University.
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms are permitted
   8  * provided that the above copyright notice and this paragraph are
   9  * duplicated in all such forms and that any documentation,
  10  * advertising materials, and other materials related to such
  11  * distribution and use acknowledge that the software was developed
  12  * by the Australian National University.  The name of the University
  13  * may not be used to endorse or promote products derived from this
  14  * software without specific prior written permission.
  15  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  17  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  18  *
  19  * Copyright (c) 1991 Gregory M. Christy.
  20  * All rights reserved.
  21  *
  22  * Redistribution and use in source and binary forms are permitted
  23  * provided that the above copyright notice and this paragraph are
  24  * duplicated in all such forms and that any documentation,
  25  * advertising materials, and other materials related to such
  26  * distribution and use acknowledge that the software was developed
  27  * by Gregory M. Christy.  The name of the author may not be used to
  28  * endorse or promote products derived from this software without
  29  * specific prior written permission.
  30  *
  31  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  32  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  33  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  34  */
  35
  36 #define RCSID   "$Id: chap.c,v 1.5 2004/10/06 10:21:52 honor Exp $"
  37
  38 /*
  39  * TODO:
  40  */
  41
  42 #include <stdio.h>
  43 #include <string.h>
  44 #include <stdlib.h>
  45 #include <sys/types.h>
  46 #include <sys/time.h>
  47
  48 #include <pppd.h>
  49 #include "chap.h"
  50 #include "md5.h"
  51 #ifdef CHAPMS
  52 #include "chap_ms.h"
  53 #endif
  54
  55 static const char rcsid[] = RCSID;
  56
  57 /*
  58  * Command-line options.
  59  */
  60 static option_t chap_option_list[] = {
  61     { "chap-restart", o_int, &chap[0].timeouttime,
  62       "Set timeout for CHAP", OPT_PRIO },
  63     { "chap-max-challenge", o_int, &chap[0].max_transmits,
  64       "Set max #xmits for challenge", OPT_PRIO },
  65     { "chap-interval", o_int, &chap[0].chal_interval,
  66       "Set interval for rechallenge", OPT_PRIO },
  67 #ifdef MSLANMAN
  68     { "ms-lanman", o_bool, &ms_lanman,
  69       "Use LanMan passwd when using MS-CHAP", 1 },
  70 #endif
  71     { NULL }
  72 };
  73
  74 /*
  75  * Protocol entry points.
  76  */
  77 static void ChapInit __P((int));
  78 static void ChapLowerUp __P((int));
  79 static void ChapLowerDown __P((int));
  80 static void ChapInput __P((int, u_char *, int));
  81 static void ChapProtocolReject __P((int));
  82 static int  ChapPrintPkt __P((u_char *, int,
  83                               void (*) __P((void *, char *, ...)), void *));
  84
  85 struct protent chap_protent = {
  86     PPP_CHAP,
  87     ChapInit,
  88     ChapInput,
  89     ChapProtocolReject,
  90     ChapLowerUp,
  91     ChapLowerDown,
  92     NULL,
  93     NULL,
  94     ChapPrintPkt,
  95     NULL,
  96     1,
  97     "CHAP",
  98     NULL,
  99     chap_option_list,
 100     NULL,
 101     NULL,
 102     NULL
 103 };
 104
 105 chap_state chap[NUM_PPP];               /* CHAP state; one for each unit */
 106
 107 static void ChapChallengeTimeout __P((void *));
 108 static void ChapResponseTimeout __P((void *));
 109 static void ChapReceiveChallenge __P((chap_state *, u_char *, int, int));
 110 static void ChapRechallenge __P((void *));
 111 static void ChapReceiveResponse __P((chap_state *, u_char *, int, int));
 112 static void ChapReceiveSuccess __P((chap_state *, u_char *, int, int));
 113 static void ChapReceiveFailure __P((chap_state *, u_char *, int, int));
 114 static void ChapSendStatus __P((chap_state *, int));
 115 static void ChapSendChallenge __P((chap_state *));
 116 static void ChapSendResponse __P((chap_state *));
 117 static void ChapGenChallenge __P((chap_state *));
 118
 119 extern double drand48 __P((void));
 120 extern void srand48 __P((long));
 121
 122 /*
 123  * ChapInit - Initialize a CHAP unit.
 124  */
 125 static void
 126 ChapInit(unit)
 127     int unit;
 128 {
 129     chap_state *cstate = &chap[unit];
 130
 131     BZERO(cstate, sizeof(*cstate));
 132     cstate->unit = unit;
 133     cstate->clientstate = CHAPCS_INITIAL;
 134     cstate->serverstate = CHAPSS_INITIAL;
 135     cstate->timeouttime = CHAP_DEFTIMEOUT;
 136     cstate->max_transmits = CHAP_DEFTRANSMITS;
 137     /* random number generator is initialized in magic_init */
 138 }
 139
 140
 141 /*
 142  * ChapAuthWithPeer - Authenticate us with our peer (start client).
 143  *
 144  */
 145 void
 146 ChapAuthWithPeer(unit, our_name, digest)
 147     int unit;
 148     char *our_name;
 149     int digest;
 150 {
 151     chap_state *cstate = &chap[unit];
 152
 153     cstate->resp_name = our_name;
 154     cstate->resp_type = digest;
 155
 156     if (cstate->clientstate == CHAPCS_INITIAL ||
 157         cstate->clientstate == CHAPCS_PENDING) {
 158         /* lower layer isn't up - wait until later */
 159         cstate->clientstate = CHAPCS_PENDING;
 160         return;
 161     }
 162
 163     /*
 164      * We get here as a result of LCP coming up.
 165      * So even if CHAP was open before, we will
 166      * have to re-authenticate ourselves.
 167      */
 168     cstate->clientstate = CHAPCS_LISTEN;
 169 }
 170
 171
 172 /*
 173  * ChapAuthPeer - Authenticate our peer (start server).
 174  */
 175 void
 176 ChapAuthPeer(unit, our_name, digest)
 177     int unit;
 178     char *our_name;
 179     int digest;
 180 {
 181     chap_state *cstate = &chap[unit];
 182
 183     cstate->chal_name = our_name;
 184     cstate->chal_type = digest;
 185
 186     if (cstate->serverstate == CHAPSS_INITIAL ||
 187         cstate->serverstate == CHAPSS_PENDING) {
 188         /* lower layer isn't up - wait until later */
 189         cstate->serverstate = CHAPSS_PENDING;
 190         return;
 191     }
 192
 193     ChapGenChallenge(cstate);
 194     ChapSendChallenge(cstate);          /* crank it up dude! */
 195     cstate->serverstate = CHAPSS_INITIAL_CHAL;
 196 }
 197
 198
 199 /*
 200  * ChapChallengeTimeout - Timeout expired on sending challenge.
 201  */
 202 static void
 203 ChapChallengeTimeout(arg)
 204     void *arg;
 205 {
 206     chap_state *cstate = (chap_state *) arg;
 207
 208     /* if we aren't sending challenges, don't worry.  then again we */
 209     /* probably shouldn't be here either */
 210     if (cstate->serverstate != CHAPSS_INITIAL_CHAL &&
 211         cstate->serverstate != CHAPSS_RECHALLENGE)
 212         return;
 213
 214     if (cstate->chal_transmits >= cstate->max_transmits) {
 215         /* give up on peer */
 216
 217         LOGX_ERROR("Peer failed to respond to CHAP challenge.");
 218         error("Peer failed to respond to CHAP challenge");
 219
 220         cstate->serverstate = CHAPSS_BADAUTH;
 221         auth_peer_fail(cstate->unit, PPP_CHAP);
 222         return;
 223     }
 224
 225     ChapSendChallenge(cstate);          /* Re-send challenge */
 226 }
 227
 228
 229 /*
 230  * ChapResponseTimeout - Timeout expired on sending response.
 231  */
 232 static void
 233 ChapResponseTimeout(arg)
 234     void *arg;
 235 {
 236     chap_state *cstate = (chap_state *) arg;
 237
 238     /* if we aren't sending a response, don't worry. */
 239     if (cstate->clientstate != CHAPCS_RESPONSE)
 240         return;
 241
 242     ChapSendResponse(cstate);           /* re-send response */
 243 }
 244
 245
 246 /*
 247  * ChapRechallenge - Time to challenge the peer again.
 248  */
 249 static void
 250 ChapRechallenge(arg)
 251     void *arg;
 252 {
 253     chap_state *cstate = (chap_state *) arg;
 254
 255     /* if we aren't sending a response, don't worry. */
 256     if (cstate->serverstate != CHAPSS_OPEN)
 257         return;
 258
 259     ChapGenChallenge(cstate);
 260     ChapSendChallenge(cstate);
 261     cstate->serverstate = CHAPSS_RECHALLENGE;
 262 }
 263
 264
 265 /*
 266  * ChapLowerUp - The lower layer is up.
 267  *
 268  * Start up if we have pending requests.
 269  */
 270 static void
 271 ChapLowerUp(unit)
 272     int unit;
 273 {
 274     chap_state *cstate = &chap[unit];
 275
 276     if (cstate->clientstate == CHAPCS_INITIAL)
 277         cstate->clientstate = CHAPCS_CLOSED;
 278     else if (cstate->clientstate == CHAPCS_PENDING)
 279         cstate->clientstate = CHAPCS_LISTEN;
 280
 281     if (cstate->serverstate == CHAPSS_INITIAL)
 282         cstate->serverstate = CHAPSS_CLOSED;
 283     else if (cstate->serverstate == CHAPSS_PENDING) {
 284         ChapGenChallenge(cstate);
 285         ChapSendChallenge(cstate);
 286         cstate->serverstate = CHAPSS_INITIAL_CHAL;
 287     }
 288 }
 289
 290
 291 /*
 292  * ChapLowerDown - The lower layer is down.
 293  *
 294  * Cancel all timeouts.
 295  */
 296 static void
 297 ChapLowerDown(unit)
 298     int unit;
 299 {
 300     chap_state *cstate = &chap[unit];
 301
 302     /* Timeout(s) pending?  Cancel if so. */
 303     if (cstate->serverstate == CHAPSS_INITIAL_CHAL ||
 304         cstate->serverstate == CHAPSS_RECHALLENGE)
 305         UNTIMEOUT(ChapChallengeTimeout, cstate);
 306     else if (cstate->serverstate == CHAPSS_OPEN
 307              && cstate->chal_interval != 0)
 308         UNTIMEOUT(ChapRechallenge, cstate);
 309     if (cstate->clientstate == CHAPCS_RESPONSE)
 310         UNTIMEOUT(ChapResponseTimeout, cstate);
 311
 312     cstate->clientstate = CHAPCS_INITIAL;
 313     cstate->serverstate = CHAPSS_INITIAL;
 314 }
 315
 316
 317 /*
 318  * ChapProtocolReject - Peer doesn't grok CHAP.
 319  */
 320 static void
 321 ChapProtocolReject(unit)
 322     int unit;
 323 {
 324     chap_state *cstate = &chap[unit];
 325
 326     if (cstate->serverstate != CHAPSS_INITIAL &&
 327         cstate->serverstate != CHAPSS_CLOSED)
 328         auth_peer_fail(unit, PPP_CHAP);
 329     if (cstate->clientstate != CHAPCS_INITIAL &&
 330         cstate->clientstate != CHAPCS_CLOSED)
 331         auth_withpeer_fail(unit, PPP_CHAP);
 332     ChapLowerDown(unit);                /* shutdown chap */
 333 }
 334
 335
 336 /*
 337  * ChapInput - Input CHAP packet.
 338  */
 339 static void
 340 ChapInput(unit, inpacket, packet_len)
 341     int unit;
 342     u_char *inpacket;
 343     int packet_len;
 344 {
 345     chap_state *cstate = &chap[unit];
 346     u_char *inp;
 347     u_char code, id;
 348     int len;
 349
 350     /*
 351      * Parse header (code, id and length).
 352      * If packet too short, drop it.
 353      */
 354     inp = inpacket;
 355     if (packet_len < CHAP_HEADERLEN) {
 356         CHAPDEBUG(("ChapInput: rcvd short header."));
 357         return;
 358     }
 359     GETCHAR(code, inp);
 360     GETCHAR(id, inp);
 361     GETSHORT(len, inp);
 362     if (len < CHAP_HEADERLEN) {
 363         CHAPDEBUG(("ChapInput: rcvd illegal length."));
 364         return;
 365     }
 366     if (len > packet_len) {
 367         CHAPDEBUG(("ChapInput: rcvd short packet."));
 368         return;
 369     }
 370     len -= CHAP_HEADERLEN;
 371
 372     /*
 373      * Action depends on code (as in fact it usually does :-).
 374      */
 375     switch (code) {
 376     case CHAP_CHALLENGE:
 377         ChapReceiveChallenge(cstate, inp, id, len);
 378         break;
 379
 380     case CHAP_RESPONSE:
 381         ChapReceiveResponse(cstate, inp, id, len);
 382         break;
 383
 384     case CHAP_FAILURE:
 385         ChapReceiveFailure(cstate, inp, id, len);
 386         break;
 387
 388     case CHAP_SUCCESS:
 389         ChapReceiveSuccess(cstate, inp, id, len);
 390         break;
 391
 392     default:                            /* Need code reject? */
 393         warn("Unknown CHAP code (%d) received.", code);
 394         break;
 395     }
 396 }
 397
 398
 399 /*
 400  * ChapReceiveChallenge - Receive Challenge and send Response.
 401  */
 402 static void
 403 ChapReceiveChallenge(cstate, inp, id, len)
 404     chap_state *cstate;
 405     u_char *inp;
 406     int id;
 407     int len;
 408 {
 409     int rchallenge_len;
 410     u_char *rchallenge;
 411     int secret_len;
 412     char secret[MAXSECRETLEN];
 413     char rhostname[256];
 414     MD5_CTX mdContext;
 415     u_char hash[MD5_SIGNATURE_SIZE];
 416
 417     if (cstate->clientstate == CHAPCS_CLOSED ||
 418         cstate->clientstate == CHAPCS_PENDING) {
 419         CHAPDEBUG(("ChapReceiveChallenge: in state %d", cstate->clientstate));
 420         return;
 421     }
 422
 423     if (len < 2) {
 424         CHAPDEBUG(("ChapReceiveChallenge: rcvd short packet."));
 425         return;
 426     }
 427
 428     GETCHAR(rchallenge_len, inp);
 429     len -= sizeof (u_char) + rchallenge_len;    /* now name field length */
 430     if (len < 0) {
 431         CHAPDEBUG(("ChapReceiveChallenge: rcvd short packet."));
 432         return;
 433     }
 434     rchallenge = inp;
 435     INCPTR(rchallenge_len, inp);
 436
 437     if (len >= sizeof(rhostname))
 438         len = sizeof(rhostname) - 1;
 439     BCOPY(inp, rhostname, len);
 440     rhostname[len] = '\000';
 441
 442     /* Microsoft doesn't send their name back in the PPP packet */
 443     if (explicit_remote || (remote_name[0] != 0 && rhostname[0] == 0)) {
 444         strlcpy(rhostname, remote_name, sizeof(rhostname));
 445         CHAPDEBUG(("ChapReceiveChallenge: using '%q' as remote name",
 446                    rhostname));
 447     }
 448
 449     /* get secret for authenticating ourselves with the specified host */
 450     if (!get_secret(cstate->unit, cstate->resp_name, rhostname,
 451                     secret, &secret_len, 0)) {
 452         secret_len = 0;         /* assume null secret if can't find one */
 453         warn("No CHAP secret found for authenticating us to %q", rhostname);
 454     }
 455
 456     /* cancel response send timeout if necessary */
 457     if (cstate->clientstate == CHAPCS_RESPONSE)
 458         UNTIMEOUT(ChapResponseTimeout, cstate);
 459
 460     cstate->resp_id = id;
 461     cstate->resp_transmits = 0;
 462
 463     /*  generate MD based on negotiated type */
 464     switch (cstate->resp_type) {
 465
 466     case CHAP_DIGEST_MD5:
 467         MD5Init(&mdContext);
 468         MD5Update(&mdContext, &cstate->resp_id, 1);
 469         MD5Update(&mdContext, secret, secret_len);
 470         MD5Update(&mdContext, rchallenge, rchallenge_len);
 471         MD5Final(hash, &mdContext);
 472         BCOPY(hash, cstate->response, MD5_SIGNATURE_SIZE);
 473         cstate->resp_length = MD5_SIGNATURE_SIZE;
 474         break;
 475
 476 #ifdef CHAPMS
 477     case CHAP_MICROSOFT:
 478         ChapMS(cstate, rchallenge, rchallenge_len, secret, secret_len);
 479         break;
 480 #endif
 481
 482     default:
 483         CHAPDEBUG(("unknown digest type %d", cstate->resp_type));
 484         return;
 485     }
 486
 487     BZERO(secret, sizeof(secret));
 488     ChapSendResponse(cstate);
 489 }
 490
 491
 492 /*
 493  * ChapReceiveResponse - Receive and process response.
 494  */
 495 static void
 496 ChapReceiveResponse(cstate, inp, id, len)
 497     chap_state *cstate;
 498     u_char *inp;
 499     int id;
 500     int len;
 501 {
 502     u_char *remmd, remmd_len;
 503     int secret_len, old_state;
 504     int code;
 505     char rhostname[256];
 506     MD5_CTX mdContext;
 507     char secret[MAXSECRETLEN];
 508     u_char hash[MD5_SIGNATURE_SIZE];
 509
 510     if (cstate->serverstate == CHAPSS_CLOSED ||
 511         cstate->serverstate == CHAPSS_PENDING) {
 512         CHAPDEBUG(("ChapReceiveResponse: in state %d", cstate->serverstate));
 513         return;
 514     }
 515
 516     if (id != cstate->chal_id)
 517         return;                 /* doesn't match ID of last challenge */
 518
 519         LOGX_INFO("Received CHAP Response.");
 520
 521     /*
 522      * If we have received a duplicate or bogus Response,
 523      * we have to send the same answer (Success/Failure)
 524      * as we did for the first Response we saw.
 525      */
 526     if (cstate->serverstate == CHAPSS_OPEN) {
 527         ChapSendStatus(cstate, CHAP_SUCCESS);
 528         return;
 529     }
 530     if (cstate->serverstate == CHAPSS_BADAUTH) {
 531         ChapSendStatus(cstate, CHAP_FAILURE);
 532         return;
 533     }
 534
 535     if (len < 2) {
 536         CHAPDEBUG(("ChapReceiveResponse: rcvd short packet."));
 537         return;
 538     }
 539     GETCHAR(remmd_len, inp);            /* get length of MD */
 540     remmd = inp;                        /* get pointer to MD */
 541     INCPTR(remmd_len, inp);
 542
 543     len -= sizeof (u_char) + remmd_len;
 544     if (len < 0) {
 545         CHAPDEBUG(("ChapReceiveResponse: rcvd short packet."));
 546         return;
 547     }
 548
 549     UNTIMEOUT(ChapChallengeTimeout, cstate);
 550
 551     if (len >= sizeof(rhostname))
 552         len = sizeof(rhostname) - 1;
 553     BCOPY(inp, rhostname, len);
 554     rhostname[len] = '\000';
 555
 556     /*
 557      * Get secret for authenticating them with us,
 558      * do the hash ourselves, and compare the result.
 559      */
 560     code = CHAP_FAILURE;
 561     if (!get_secret(cstate->unit, (explicit_remote? remote_name: rhostname),
 562                     cstate->chal_name, secret, &secret_len, 1)) {
 563         warn("No CHAP secret found for authenticating %q", rhostname);
 564     } else {
 565
 566         /*  generate MD based on negotiated type */
 567         switch (cstate->chal_type) {
 568
 569         case CHAP_DIGEST_MD5:           /* only MD5 is defined for now */
 570             if (remmd_len != MD5_SIGNATURE_SIZE)
 571                 break;                  /* it's not even the right length */
 572             MD5Init(&mdContext);
 573             MD5Update(&mdContext, &cstate->chal_id, 1);
 574             MD5Update(&mdContext, secret, secret_len);
 575             MD5Update(&mdContext, cstate->challenge, cstate->chal_len);
 576             MD5Final(hash, &mdContext);
 577
 578             /* compare local and remote MDs and send the appropriate status */
 579             if (memcmp (hash, remmd, MD5_SIGNATURE_SIZE) == 0)
 580                 code = CHAP_SUCCESS;    /* they are the same! */
 581             break;
 582
 583         default:
 584             CHAPDEBUG(("unknown digest type %d", cstate->chal_type));
 585         }
 586     }
 587
 588     BZERO(secret, sizeof(secret));
 589     ChapSendStatus(cstate, code);
 590
 591     if (code == CHAP_SUCCESS) {
 592         old_state = cstate->serverstate;
 593         cstate->serverstate = CHAPSS_OPEN;
 594         if (old_state == CHAPSS_INITIAL_CHAL) {
 595             auth_peer_success(cstate->unit, PPP_CHAP, rhostname, len);
 596         }
 597         if (cstate->chal_interval != 0)
 598             TIMEOUT(ChapRechallenge, cstate, cstate->chal_interval);
 599
 600         LOGX_INFO("CHAP peer authentication succeeded for %s.", rhostname);
 601         notice("CHAP peer authentication succeeded for %q", rhostname);
 602
 603     } else {
 604         LOGX_WARN("CHAP peer authentication failed for remote host %s.", rhostname);
 605         error("CHAP peer authentication failed for remote host %q", rhostname);
 606         cstate->serverstate = CHAPSS_BADAUTH;
 607         auth_peer_fail(cstate->unit, PPP_CHAP);
 608     }
 609 }
 610
 611 /*
 612  * ChapReceiveSuccess - Receive Success
 613  */
 614 static void
 615 ChapReceiveSuccess(cstate, inp, id, len)
 616     chap_state *cstate;
 617     u_char *inp;
 618     u_char id;
 619     int len;
 620 {
 621
 622     if (cstate->clientstate == CHAPCS_OPEN)
 623         /* presumably an answer to a duplicate response */
 624         return;
 625
 626     if (cstate->clientstate != CHAPCS_RESPONSE) {
 627         /* don't know what this is */
 628         CHAPDEBUG(("ChapReceiveSuccess: in state %d\n", cstate->clientstate));
 629         return;
 630     }
 631
 632         LOGX_INFO("CHAP authentication succeeded.");
 633     UNTIMEOUT(ChapResponseTimeout, cstate);
 634
 635     /*
 636      * Print message.
 637      */
 638     if (len > 0)
 639         PRINTMSG(inp, len);
 640
 641     cstate->clientstate = CHAPCS_OPEN;
 642
 643     auth_withpeer_success(cstate->unit, PPP_CHAP);
 644 }
 645
 646
 647 /*
 648  * ChapReceiveFailure - Receive failure.
 649  */
 650 static void
 651 ChapReceiveFailure(cstate, inp, id, len)
 652     chap_state *cstate;
 653     u_char *inp;
 654     u_char id;
 655     int len;
 656 {
 657     if (cstate->clientstate != CHAPCS_RESPONSE) {
 658         /* don't know what this is */
 659         CHAPDEBUG(("ChapReceiveFailure: in state %d\n", cstate->clientstate));
 660         return;
 661     }
 662
 663     UNTIMEOUT(ChapResponseTimeout, cstate);
 664
 665     /*
 666      * Print message.
 667      */
 668     if (len > 0)
 669         PRINTMSG(inp, len);
 670
 671         LOGX_ERROR("CHAP authentication failed.");
 672     error("CHAP authentication failed");
 673
 674     //log_to_file("CHAP_AUTH_FAIL");
 675     system("ppp_event -t CHAP_AUTH_FAIL &");
 676
 677     auth_withpeer_fail(cstate->unit, PPP_CHAP);
 678 }
 679
 680
 681 /*
 682  * ChapSendChallenge - Send an Authenticate challenge.
 683  */
 684 static void
 685 ChapSendChallenge(cstate)
 686     chap_state *cstate;
 687 {
 688     u_char *outp;
 689     int chal_len, name_len;
 690     int outlen;
 691
 692         LOGX_INFO("Sending CHAP challenge.");
 693
 694     chal_len = cstate->chal_len;
 695     name_len = strlen(cstate->chal_name);
 696     outlen = CHAP_HEADERLEN + sizeof (u_char) + chal_len + name_len;
 697     outp = outpacket_buf;
 698
 699     MAKEHEADER(outp, PPP_CHAP);         /* paste in a CHAP header */
 700
 701     PUTCHAR(CHAP_CHALLENGE, outp);
 702     PUTCHAR(cstate->chal_id, outp);
 703     PUTSHORT(outlen, outp);
 704
 705     PUTCHAR(chal_len, outp);            /* put length of challenge */
 706     BCOPY(cstate->challenge, outp, chal_len);
 707     INCPTR(chal_len, outp);
 708
 709     BCOPY(cstate->chal_name, outp, name_len);   /* append hostname */
 710
 711     output(cstate->unit, outpacket_buf, outlen + PPP_HDRLEN);
 712
 713     TIMEOUT(ChapChallengeTimeout, cstate, cstate->timeouttime);
 714     ++cstate->chal_transmits;
 715 }
 716
 717
 718 /*
 719  * ChapSendStatus - Send a status response (ack or nak).
 720  */
 721 static void
 722 ChapSendStatus(cstate, code)
 723     chap_state *cstate;
 724     int code;
 725 {
 726     u_char *outp;
 727     int outlen, msglen;
 728     char msg[256];
 729
 730         LOGX_INFO("Sending CHAP %s.", (code == CHAP_SUCCESS ? "Success" : "Failure"));
 731
 732     if (code == CHAP_SUCCESS)
 733         slprintf(msg, sizeof(msg), "Welcome to %s.", hostname);
 734     else
 735         slprintf(msg, sizeof(msg), "I don't like you.  Go 'way.");
 736     msglen = strlen(msg);
 737
 738     outlen = CHAP_HEADERLEN + msglen;
 739     outp = outpacket_buf;
 740
 741     MAKEHEADER(outp, PPP_CHAP); /* paste in a header */
 742
 743     PUTCHAR(code, outp);
 744     PUTCHAR(cstate->chal_id, outp);
 745     PUTSHORT(outlen, outp);
 746     BCOPY(msg, outp, msglen);
 747     output(cstate->unit, outpacket_buf, outlen + PPP_HDRLEN);
 748 }
 749
 750 /*
 751  * ChapGenChallenge is used to generate a pseudo-random challenge string of
 752  * a pseudo-random length between min_len and max_len.  The challenge
 753  * string and its length are stored in *cstate, and various other fields of
 754  * *cstate are initialized.
 755  */
 756
 757 static void
 758 ChapGenChallenge(cstate)
 759     chap_state *cstate;
 760 {
 761     int chal_len;
 762     u_char *ptr = cstate->challenge;
 763     int i;
 764
 765     /* pick a random challenge length between MIN_CHALLENGE_LENGTH and
 766        MAX_CHALLENGE_LENGTH */
 767     chal_len =  (unsigned) ((drand48() *
 768                              (MAX_CHALLENGE_LENGTH - MIN_CHALLENGE_LENGTH)) +
 769                             MIN_CHALLENGE_LENGTH);
 770     cstate->chal_len = chal_len;
 771     cstate->chal_id = ++cstate->id;
 772     cstate->chal_transmits = 0;
 773
 774     /* generate a random string */
 775     for (i = 0; i < chal_len; i++)
 776         *ptr++ = (char) (drand48() * 0xff);
 777 }
 778
 779 /*
 780  * ChapSendResponse - send a response packet with values as specified
 781  * in *cstate.
 782  */
 783 /* ARGSUSED */
 784 static void
 785 ChapSendResponse(cstate)
 786     chap_state *cstate;
 787 {
 788     u_char *outp;
 789     int outlen, md_len, name_len;
 790
 791     md_len = cstate->resp_length;
 792     name_len = strlen(cstate->resp_name);
 793     outlen = CHAP_HEADERLEN + sizeof (u_char) + md_len + name_len;
 794     outp = outpacket_buf;
 795
 796     MAKEHEADER(outp, PPP_CHAP);
 797
 798     PUTCHAR(CHAP_RESPONSE, outp);       /* we are a response */
 799     PUTCHAR(cstate->resp_id, outp);     /* copy id from challenge packet */
 800     PUTSHORT(outlen, outp);             /* packet length */
 801
 802     PUTCHAR(md_len, outp);              /* length of MD */
 803     BCOPY(cstate->response, outp, md_len);      /* copy MD to buffer */
 804     INCPTR(md_len, outp);
 805
 806     BCOPY(cstate->resp_name, outp, name_len); /* append our name */
 807
 808     /* send the packet */
 809     output(cstate->unit, outpacket_buf, outlen + PPP_HDRLEN);
 810
 811     cstate->clientstate = CHAPCS_RESPONSE;
 812     TIMEOUT(ChapResponseTimeout, cstate, cstate->timeouttime);
 813     ++cstate->resp_transmits;
 814 }
 815
 816 /*
 817  * ChapPrintPkt - print the contents of a CHAP packet.
 818  */
 819 static char *ChapCodenames[] = {
 820     "Challenge", "Response", "Success", "Failure"
 821 };
 822
 823 static int
 824 ChapPrintPkt(p, plen, printer, arg)
 825     u_char *p;
 826     int plen;
 827     void (*printer) __P((void *, char *, ...));
 828     void *arg;
 829 {
 830     int code, id, len;
 831     int clen, nlen;
 832     u_char x;
 833
 834     if (plen < CHAP_HEADERLEN)
 835         return 0;
 836     GETCHAR(code, p);
 837     GETCHAR(id, p);
 838     GETSHORT(len, p);
 839     if (len < CHAP_HEADERLEN || len > plen)
 840         return 0;
 841
 842     if (code >= 1 && code <= sizeof(ChapCodenames) / sizeof(char *))
 843         printer(arg, " %s", ChapCodenames[code-1]);
 844     else
 845         printer(arg, " code=0x%x", code);
 846     printer(arg, " id=0x%x", id);
 847     len -= CHAP_HEADERLEN;
 848     switch (code) {
 849     case CHAP_CHALLENGE:
 850     case CHAP_RESPONSE:
 851         if (len < 1)
 852             break;
 853         clen = p[0];
 854         if (len < clen + 1)
 855             break;
 856         ++p;
 857         nlen = len - clen - 1;
 858         printer(arg, " <");
 859         for (; clen > 0; --clen) {
 860             GETCHAR(x, p);
 861             printer(arg, "%.2x", x);
 862         }
 863         printer(arg, ">, name = ");
 864         print_string((char *)p, nlen, printer, arg);
 865         break;
 866     case CHAP_FAILURE:
 867     case CHAP_SUCCESS:
 868         printer(arg, " ");
 869         print_string((char *)p, len, printer, arg);
 870         break;
 871     default:
 872         for (clen = len; clen > 0; --clen) {
 873             GETCHAR(x, p);
 874             printer(arg, " %.2x", x);
 875         }
 876     }
 877
 878     return len + CHAP_HEADERLEN;
 879 }