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 #ifndef lint
  37 static char rcsid[] = "$Id: chap.c,v 1.12 1996/05/28 00:42:27 paulus Exp $";
  38 #endif
  39
  40 /*
  41  * TODO:
  42  */
  43
  44 #include <stdio.h>
  45 #include <string.h>
  46 #include <sys/types.h>
  47 #include <sys/time.h>
  48 #include <syslog.h>
  49
  50 #include "pppd.h"
  51 #include "chap.h"
  52 #include "md5.h"
  53 #ifdef CHAPMS
  54 #include "chap_ms.h"
  55 #endif
  56
  57 struct protent chap_protent = {
  58     PPP_CHAP, ChapInit, ChapInput, ChapProtocolReject,
  59     ChapLowerUp, ChapLowerDown, NULL, NULL,
  60     ChapPrintPkt, NULL, 1, "CHAP", NULL, NULL
  61 };
  62
  63 chap_state chap[NUM_PPP];               /* CHAP state; one for each unit */
  64
  65 static void ChapChallengeTimeout __P((caddr_t));
  66 static void ChapResponseTimeout __P((caddr_t));
  67 static void ChapReceiveChallenge __P((chap_state *, u_char *, int, int));
  68 static void ChapReceiveResponse __P((chap_state *, u_char *, int, int));
  69 static void ChapReceiveSuccess __P((chap_state *, u_char *, int, int));
  70 static void ChapReceiveFailure __P((chap_state *, u_char *, int, int));
  71 static void ChapSendStatus __P((chap_state *, int));
  72 static void ChapSendChallenge __P((chap_state *));
  73 static void ChapSendResponse __P((chap_state *));
  74 static void ChapGenChallenge __P((chap_state *));
  75
  76 extern double drand48 __P((void));
  77 extern void srand48 __P((long));
  78
  79 /*
  80  * ChapInit - Initialize a CHAP unit.
  81  */
  82 void
  83 ChapInit(unit)
  84     int unit;
  85 {
  86     chap_state *cstate = &chap[unit];
  87
  88     BZERO(cstate, sizeof(*cstate));
  89     cstate->unit = unit;
  90     cstate->clientstate = CHAPCS_INITIAL;
  91     cstate->serverstate = CHAPSS_INITIAL;
  92     cstate->timeouttime = CHAP_DEFTIMEOUT;
  93     cstate->max_transmits = CHAP_DEFTRANSMITS;
  94     /* random number generator is initialized in magic_init */
  95 }
  96
  97
  98 /*
  99  * ChapAuthWithPeer - Authenticate us with our peer (start client).
 100  *
 101  */
 102 void
 103 ChapAuthWithPeer(unit, our_name, digest)
 104     int unit;
 105     char *our_name;
 106     int digest;
 107 {
 108     chap_state *cstate = &chap[unit];
 109
 110     cstate->resp_name = our_name;
 111     cstate->resp_type = digest;
 112
 113     if (cstate->clientstate == CHAPCS_INITIAL ||
 114         cstate->clientstate == CHAPCS_PENDING) {
 115         /* lower layer isn't up - wait until later */
 116         cstate->clientstate = CHAPCS_PENDING;
 117         return;
 118     }
 119
 120     /*
 121      * We get here as a result of LCP coming up.
 122      * So even if CHAP was open before, we will
 123      * have to re-authenticate ourselves.
 124      */
 125     cstate->clientstate = CHAPCS_LISTEN;
 126 }
 127
 128
 129 /*
 130  * ChapAuthPeer - Authenticate our peer (start server).
 131  */
 132 void
 133 ChapAuthPeer(unit, our_name, digest)
 134     int unit;
 135     char *our_name;
 136     int digest;
 137 {
 138     chap_state *cstate = &chap[unit];
 139
 140     cstate->chal_name = our_name;
 141     cstate->chal_type = digest;
 142
 143     if (cstate->serverstate == CHAPSS_INITIAL ||
 144         cstate->serverstate == CHAPSS_PENDING) {
 145         /* lower layer isn't up - wait until later */
 146         cstate->serverstate = CHAPSS_PENDING;
 147         return;
 148     }
 149
 150     ChapGenChallenge(cstate);
 151     ChapSendChallenge(cstate);          /* crank it up dude! */
 152     cstate->serverstate = CHAPSS_INITIAL_CHAL;
 153 }
 154
 155
 156 /*
 157  * ChapChallengeTimeout - Timeout expired on sending challenge.
 158  */
 159 static void
 160 ChapChallengeTimeout(arg)
 161     caddr_t arg;
 162 {
 163     chap_state *cstate = (chap_state *) arg;
 164
 165     /* if we aren't sending challenges, don't worry.  then again we */
 166     /* probably shouldn't be here either */
 167     if (cstate->serverstate != CHAPSS_INITIAL_CHAL &&
 168         cstate->serverstate != CHAPSS_RECHALLENGE)
 169         return;
 170
 171     if (cstate->chal_transmits >= cstate->max_transmits) {
 172         /* give up on peer */
 173         syslog(LOG_ERR, "Peer failed to respond to CHAP challenge");
 174         cstate->serverstate = CHAPSS_BADAUTH;
 175         auth_peer_fail(cstate->unit, PPP_CHAP);
 176         return;
 177     }
 178
 179     ChapSendChallenge(cstate);          /* Re-send challenge */
 180 }
 181
 182
 183 /*
 184  * ChapResponseTimeout - Timeout expired on sending response.
 185  */
 186 static void
 187 ChapResponseTimeout(arg)
 188     caddr_t arg;
 189 {
 190     chap_state *cstate = (chap_state *) arg;
 191
 192     /* if we aren't sending a response, don't worry. */
 193     if (cstate->clientstate != CHAPCS_RESPONSE)
 194         return;
 195
 196     ChapSendResponse(cstate);           /* re-send response */
 197 }
 198
 199
 200 /*
 201  * ChapRechallenge - Time to challenge the peer again.
 202  */
 203 static void
 204 ChapRechallenge(arg)
 205     caddr_t arg;
 206 {
 207     chap_state *cstate = (chap_state *) arg;
 208
 209     /* if we aren't sending a response, don't worry. */
 210     if (cstate->serverstate != CHAPSS_OPEN)
 211         return;
 212
 213     ChapGenChallenge(cstate);
 214     ChapSendChallenge(cstate);
 215     cstate->serverstate = CHAPSS_RECHALLENGE;
 216 }
 217
 218
 219 /*
 220  * ChapLowerUp - The lower layer is up.
 221  *
 222  * Start up if we have pending requests.
 223  */
 224 void
 225 ChapLowerUp(unit)
 226     int unit;
 227 {
 228     chap_state *cstate = &chap[unit];
 229
 230     if (cstate->clientstate == CHAPCS_INITIAL)
 231         cstate->clientstate = CHAPCS_CLOSED;
 232     else if (cstate->clientstate == CHAPCS_PENDING)
 233         cstate->clientstate = CHAPCS_LISTEN;
 234
 235     if (cstate->serverstate == CHAPSS_INITIAL)
 236         cstate->serverstate = CHAPSS_CLOSED;
 237     else if (cstate->serverstate == CHAPSS_PENDING) {
 238         ChapGenChallenge(cstate);
 239         ChapSendChallenge(cstate);
 240         cstate->serverstate = CHAPSS_INITIAL_CHAL;
 241     }
 242 }
 243
 244
 245 /*
 246  * ChapLowerDown - The lower layer is down.
 247  *
 248  * Cancel all timeouts.
 249  */
 250 void
 251 ChapLowerDown(unit)
 252     int unit;
 253 {
 254     chap_state *cstate = &chap[unit];
 255
 256     /* Timeout(s) pending?  Cancel if so. */
 257     if (cstate->serverstate == CHAPSS_INITIAL_CHAL ||
 258         cstate->serverstate == CHAPSS_RECHALLENGE)
 259         UNTIMEOUT(ChapChallengeTimeout, (caddr_t) cstate);
 260     else if (cstate->serverstate == CHAPSS_OPEN
 261              && cstate->chal_interval != 0)
 262         UNTIMEOUT(ChapRechallenge, (caddr_t) cstate);
 263     if (cstate->clientstate == CHAPCS_RESPONSE)
 264         UNTIMEOUT(ChapResponseTimeout, (caddr_t) cstate);
 265
 266     cstate->clientstate = CHAPCS_INITIAL;
 267     cstate->serverstate = CHAPSS_INITIAL;
 268 }
 269
 270
 271 /*
 272  * ChapProtocolReject - Peer doesn't grok CHAP.
 273  */
 274 void
 275 ChapProtocolReject(unit)
 276     int unit;
 277 {
 278     chap_state *cstate = &chap[unit];
 279
 280     if (cstate->serverstate != CHAPSS_INITIAL &&
 281         cstate->serverstate != CHAPSS_CLOSED)
 282         auth_peer_fail(unit, PPP_CHAP);
 283     if (cstate->clientstate != CHAPCS_INITIAL &&
 284         cstate->clientstate != CHAPCS_CLOSED)
 285         auth_withpeer_fail(unit, PPP_CHAP);
 286     ChapLowerDown(unit);                /* shutdown chap */
 287 }
 288
 289
 290 /*
 291  * ChapInput - Input CHAP packet.
 292  */
 293 void
 294 ChapInput(unit, inpacket, packet_len)
 295     int unit;
 296     u_char *inpacket;
 297     int packet_len;
 298 {
 299     chap_state *cstate = &chap[unit];
 300     u_char *inp;
 301     u_char code, id;
 302     int len;
 303
 304     /*
 305      * Parse header (code, id and length).
 306      * If packet too short, drop it.
 307      */
 308     inp = inpacket;
 309     if (packet_len < CHAP_HEADERLEN) {
 310         CHAPDEBUG((LOG_INFO, "ChapInput: rcvd short header."));
 311         return;
 312     }
 313     GETCHAR(code, inp);
 314     GETCHAR(id, inp);
 315     GETSHORT(len, inp);
 316     if (len < CHAP_HEADERLEN) {
 317         CHAPDEBUG((LOG_INFO, "ChapInput: rcvd illegal length."));
 318         return;
 319     }
 320     if (len > packet_len) {
 321         CHAPDEBUG((LOG_INFO, "ChapInput: rcvd short packet."));
 322         return;
 323     }
 324     len -= CHAP_HEADERLEN;
 325
 326     /*
 327      * Action depends on code (as in fact it usually does :-).
 328      */
 329     switch (code) {
 330     case CHAP_CHALLENGE:
 331         ChapReceiveChallenge(cstate, inp, id, len);
 332         break;
 333
 334     case CHAP_RESPONSE:
 335         ChapReceiveResponse(cstate, inp, id, len);
 336         break;
 337
 338     case CHAP_FAILURE:
 339         ChapReceiveFailure(cstate, inp, id, len);
 340         break;
 341
 342     case CHAP_SUCCESS:
 343         ChapReceiveSuccess(cstate, inp, id, len);
 344         break;
 345
 346     default:                            /* Need code reject? */
 347         syslog(LOG_WARNING, "Unknown CHAP code (%d) received.", code);
 348         break;
 349     }
 350 }
 351
 352
 353 /*
 354  * ChapReceiveChallenge - Receive Challenge and send Response.
 355  */
 356 static void
 357 ChapReceiveChallenge(cstate, inp, id, len)
 358     chap_state *cstate;
 359     u_char *inp;
 360     int id;
 361     int len;
 362 {
 363     int rchallenge_len;
 364     u_char *rchallenge;
 365     int secret_len;
 366     char secret[MAXSECRETLEN];
 367     char rhostname[256];
 368     MD5_CTX mdContext;
 369
 370     CHAPDEBUG((LOG_INFO, "ChapReceiveChallenge: Rcvd id %d.", id));
 371     if (cstate->clientstate == CHAPCS_CLOSED ||
 372         cstate->clientstate == CHAPCS_PENDING) {
 373         CHAPDEBUG((LOG_INFO, "ChapReceiveChallenge: in state %d",
 374                    cstate->clientstate));
 375         return;
 376     }
 377
 378     if (len < 2) {
 379         CHAPDEBUG((LOG_INFO, "ChapReceiveChallenge: rcvd short packet."));
 380         return;
 381     }
 382
 383     GETCHAR(rchallenge_len, inp);
 384     len -= sizeof (u_char) + rchallenge_len;    /* now name field length */
 385     if (len < 0) {
 386         CHAPDEBUG((LOG_INFO, "ChapReceiveChallenge: rcvd short packet."));
 387         return;
 388     }
 389     rchallenge = inp;
 390     INCPTR(rchallenge_len, inp);
 391
 392     if (len >= sizeof(rhostname))
 393         len = sizeof(rhostname) - 1;
 394     BCOPY(inp, rhostname, len);
 395     rhostname[len] = '\000';
 396
 397     CHAPDEBUG((LOG_INFO, "ChapReceiveChallenge: received name field '%s'",
 398                rhostname));
 399
 400     /* Microsoft doesn't send their name back in the PPP packet */
 401     if (rhostname[0] == 0 && cstate->resp_type == CHAP_MICROSOFT) {
 402         strcpy(rhostname, remote_name);
 403         CHAPDEBUG((LOG_INFO, "ChapReceiveChallenge: using '%s' as remote name",
 404                    rhostname));
 405     }
 406
 407     /* get secret for authenticating ourselves with the specified host */
 408     if (!get_secret(cstate->unit, cstate->resp_name, rhostname,
 409                     secret, &secret_len, 0)) {
 410         secret_len = 0;         /* assume null secret if can't find one */
 411         syslog(LOG_WARNING, "No CHAP secret found for authenticating us to %s",
 412                rhostname);
 413     }
 414
 415     /* cancel response send timeout if necessary */
 416     if (cstate->clientstate == CHAPCS_RESPONSE)
 417         UNTIMEOUT(ChapResponseTimeout, (caddr_t) cstate);
 418
 419     cstate->resp_id = id;
 420     cstate->resp_transmits = 0;
 421
 422     /*  generate MD based on negotiated type */
 423     switch (cstate->resp_type) {
 424
 425     case CHAP_DIGEST_MD5:
 426         MD5Init(&mdContext);
 427         MD5Update(&mdContext, &cstate->resp_id, 1);
 428         MD5Update(&mdContext, secret, secret_len);
 429         MD5Update(&mdContext, rchallenge, rchallenge_len);
 430         MD5Final(&mdContext);
 431         BCOPY(mdContext.digest, cstate->response, MD5_SIGNATURE_SIZE);
 432         cstate->resp_length = MD5_SIGNATURE_SIZE;
 433         break;
 434
 435 #ifdef CHAPMS
 436     case CHAP_MICROSOFT:
 437         ChapMS(cstate, rchallenge, rchallenge_len, secret, secret_len);
 438         break;
 439 #endif
 440
 441     default:
 442         CHAPDEBUG((LOG_INFO, "unknown digest type %d", cstate->resp_type));
 443         return;
 444     }
 445
 446     ChapSendResponse(cstate);
 447 }
 448
 449
 450 /*
 451  * ChapReceiveResponse - Receive and process response.
 452  */
 453 static void
 454 ChapReceiveResponse(cstate, inp, id, len)
 455     chap_state *cstate;
 456     u_char *inp;
 457     int id;
 458     int len;
 459 {
 460     u_char *remmd, remmd_len;
 461     int secret_len, old_state;
 462     int code;
 463     char rhostname[256];
 464     MD5_CTX mdContext;
 465     char secret[MAXSECRETLEN];
 466
 467     CHAPDEBUG((LOG_INFO, "ChapReceiveResponse: Rcvd id %d.", id));
 468
 469     if (cstate->serverstate == CHAPSS_CLOSED ||
 470         cstate->serverstate == CHAPSS_PENDING) {
 471         CHAPDEBUG((LOG_INFO, "ChapReceiveResponse: in state %d",
 472                    cstate->serverstate));
 473         return;
 474     }
 475
 476     if (id != cstate->chal_id)
 477         return;                 /* doesn't match ID of last challenge */
 478
 479     /*
 480      * If we have received a duplicate or bogus Response,
 481      * we have to send the same answer (Success/Failure)
 482      * as we did for the first Response we saw.
 483      */
 484     if (cstate->serverstate == CHAPSS_OPEN) {
 485         ChapSendStatus(cstate, CHAP_SUCCESS);
 486         return;
 487     }
 488     if (cstate->serverstate == CHAPSS_BADAUTH) {
 489         ChapSendStatus(cstate, CHAP_FAILURE);
 490         return;
 491     }
 492
 493     if (len < 2) {
 494         CHAPDEBUG((LOG_INFO, "ChapReceiveResponse: rcvd short packet."));
 495         return;
 496     }
 497     GETCHAR(remmd_len, inp);            /* get length of MD */
 498     remmd = inp;                        /* get pointer to MD */
 499     INCPTR(remmd_len, inp);
 500
 501     len -= sizeof (u_char) + remmd_len;
 502     if (len < 0) {
 503         CHAPDEBUG((LOG_INFO, "ChapReceiveResponse: rcvd short packet."));
 504         return;
 505     }
 506
 507     UNTIMEOUT(ChapChallengeTimeout, (caddr_t) cstate);
 508
 509     if (len >= sizeof(rhostname))
 510         len = sizeof(rhostname) - 1;
 511     BCOPY(inp, rhostname, len);
 512     rhostname[len] = '\000';
 513
 514     CHAPDEBUG((LOG_INFO, "ChapReceiveResponse: received name field: %s",
 515                rhostname));
 516
 517     /*
 518      * Get secret for authenticating them with us,
 519      * do the hash ourselves, and compare the result.
 520      */
 521     code = CHAP_FAILURE;
 522     if (!get_secret(cstate->unit, rhostname, cstate->chal_name,
 523                    secret, &secret_len, 1)) {
 524         syslog(LOG_WARNING, "No CHAP secret found for authenticating %s",
 525                rhostname);
 526     } else {
 527
 528         /*  generate MD based on negotiated type */
 529         switch (cstate->chal_type) {
 530
 531         case CHAP_DIGEST_MD5:           /* only MD5 is defined for now */
 532             if (remmd_len != MD5_SIGNATURE_SIZE)
 533                 break;                  /* it's not even the right length */
 534             MD5Init(&mdContext);
 535             MD5Update(&mdContext, &cstate->chal_id, 1);
 536             MD5Update(&mdContext, secret, secret_len);
 537             MD5Update(&mdContext, cstate->challenge, cstate->chal_len);
 538             MD5Final(&mdContext);
 539
 540             /* compare local and remote MDs and send the appropriate status */
 541             if (memcmp (mdContext.digest, remmd, MD5_SIGNATURE_SIZE) == 0)
 542                 code = CHAP_SUCCESS;    /* they are the same! */
 543             break;
 544
 545         default:
 546             CHAPDEBUG((LOG_INFO, "unknown digest type %d", cstate->chal_type));
 547         }
 548     }
 549
 550     ChapSendStatus(cstate, code);
 551
 552     if (code == CHAP_SUCCESS) {
 553         old_state = cstate->serverstate;
 554         cstate->serverstate = CHAPSS_OPEN;
 555         if (old_state == CHAPSS_INITIAL_CHAL) {
 556             auth_peer_success(cstate->unit, PPP_CHAP);
 557         }
 558         if (cstate->chal_interval != 0)
 559             TIMEOUT(ChapRechallenge, (caddr_t) cstate, cstate->chal_interval);
 560
 561     } else {
 562         syslog(LOG_ERR, "CHAP peer authentication failed");
 563         cstate->serverstate = CHAPSS_BADAUTH;
 564         auth_peer_fail(cstate->unit, PPP_CHAP);
 565     }
 566 }
 567
 568 /*
 569  * ChapReceiveSuccess - Receive Success
 570  */
 571 static void
 572 ChapReceiveSuccess(cstate, inp, id, len)
 573     chap_state *cstate;
 574     u_char *inp;
 575     u_char id;
 576     int len;
 577 {
 578
 579     CHAPDEBUG((LOG_INFO, "ChapReceiveSuccess: Rcvd id %d.", id));
 580
 581     if (cstate->clientstate == CHAPCS_OPEN)
 582         /* presumably an answer to a duplicate response */
 583         return;
 584
 585     if (cstate->clientstate != CHAPCS_RESPONSE) {
 586         /* don't know what this is */
 587         CHAPDEBUG((LOG_INFO, "ChapReceiveSuccess: in state %d\n",
 588                    cstate->clientstate));
 589         return;
 590     }
 591
 592     UNTIMEOUT(ChapResponseTimeout, (caddr_t) cstate);
 593
 594     /*
 595      * Print message.
 596      */
 597     if (len > 0)
 598         PRINTMSG(inp, len);
 599
 600     cstate->clientstate = CHAPCS_OPEN;
 601
 602     auth_withpeer_success(cstate->unit, PPP_CHAP);
 603 }
 604
 605
 606 /*
 607  * ChapReceiveFailure - Receive failure.
 608  */
 609 static void
 610 ChapReceiveFailure(cstate, inp, id, len)
 611     chap_state *cstate;
 612     u_char *inp;
 613     u_char id;
 614     int len;
 615 {
 616     CHAPDEBUG((LOG_INFO, "ChapReceiveFailure: Rcvd id %d.", id));
 617
 618     if (cstate->clientstate != CHAPCS_RESPONSE) {
 619         /* don't know what this is */
 620         CHAPDEBUG((LOG_INFO, "ChapReceiveFailure: in state %d\n",
 621                    cstate->clientstate));
 622         return;
 623     }
 624
 625     UNTIMEOUT(ChapResponseTimeout, (caddr_t) cstate);
 626
 627     /*
 628      * Print message.
 629      */
 630     if (len > 0)
 631         PRINTMSG(inp, len);
 632
 633     syslog(LOG_ERR, "CHAP authentication failed");
 634     auth_withpeer_fail(cstate->unit, PPP_CHAP);
 635 }
 636
 637
 638 /*
 639  * ChapSendChallenge - Send an Authenticate challenge.
 640  */
 641 static void
 642 ChapSendChallenge(cstate)
 643     chap_state *cstate;
 644 {
 645     u_char *outp;
 646     int chal_len, name_len;
 647     int outlen;
 648
 649     chal_len = cstate->chal_len;
 650     name_len = strlen(cstate->chal_name);
 651     outlen = CHAP_HEADERLEN + sizeof (u_char) + chal_len + name_len;
 652     outp = outpacket_buf;
 653
 654     MAKEHEADER(outp, PPP_CHAP);         /* paste in a CHAP header */
 655
 656     PUTCHAR(CHAP_CHALLENGE, outp);
 657     PUTCHAR(cstate->chal_id, outp);
 658     PUTSHORT(outlen, outp);
 659
 660     PUTCHAR(chal_len, outp);            /* put length of challenge */
 661     BCOPY(cstate->challenge, outp, chal_len);
 662     INCPTR(chal_len, outp);
 663
 664     BCOPY(cstate->chal_name, outp, name_len);   /* append hostname */
 665
 666     output(cstate->unit, outpacket_buf, outlen + PPP_HDRLEN);
 667
 668     CHAPDEBUG((LOG_INFO, "ChapSendChallenge: Sent id %d.", cstate->chal_id));
 669
 670     TIMEOUT(ChapChallengeTimeout, (caddr_t) cstate, cstate->timeouttime);
 671     ++cstate->chal_transmits;
 672 }
 673
 674
 675 /*
 676  * ChapSendStatus - Send a status response (ack or nak).
 677  */
 678 static void
 679 ChapSendStatus(cstate, code)
 680     chap_state *cstate;
 681     int code;
 682 {
 683     u_char *outp;
 684     int outlen, msglen;
 685     char msg[256];
 686
 687     if (code == CHAP_SUCCESS)
 688         sprintf(msg, "Welcome to %s.", hostname);
 689     else
 690         sprintf(msg, "I don't like you.  Go 'way.");
 691     msglen = strlen(msg);
 692
 693     outlen = CHAP_HEADERLEN + msglen;
 694     outp = outpacket_buf;
 695
 696     MAKEHEADER(outp, PPP_CHAP); /* paste in a header */
 697
 698     PUTCHAR(code, outp);
 699     PUTCHAR(cstate->chal_id, outp);
 700     PUTSHORT(outlen, outp);
 701     BCOPY(msg, outp, msglen);
 702     output(cstate->unit, outpacket_buf, outlen + PPP_HDRLEN);
 703
 704     CHAPDEBUG((LOG_INFO, "ChapSendStatus: Sent code %d, id %d.", code,
 705                cstate->chal_id));
 706 }
 707
 708 /*
 709  * ChapGenChallenge is used to generate a pseudo-random challenge string of
 710  * a pseudo-random length between min_len and max_len.  The challenge
 711  * string and its length are stored in *cstate, and various other fields of
 712  * *cstate are initialized.
 713  */
 714
 715 static void
 716 ChapGenChallenge(cstate)
 717     chap_state *cstate;
 718 {
 719     int chal_len;
 720     u_char *ptr = cstate->challenge;
 721     unsigned int i;
 722
 723     /* pick a random challenge length between MIN_CHALLENGE_LENGTH and
 724        MAX_CHALLENGE_LENGTH */
 725     chal_len =  (unsigned) ((drand48() *
 726                              (MAX_CHALLENGE_LENGTH - MIN_CHALLENGE_LENGTH)) +
 727                             MIN_CHALLENGE_LENGTH);
 728     cstate->chal_len = chal_len;
 729     cstate->chal_id = ++cstate->id;
 730     cstate->chal_transmits = 0;
 731
 732     /* generate a random string */
 733     for (i = 0; i < chal_len; i++ )
 734         *ptr++ = (char) (drand48() * 0xff);
 735 }
 736
 737 /*
 738  * ChapSendResponse - send a response packet with values as specified
 739  * in *cstate.
 740  */
 741 /* ARGSUSED */
 742 static void
 743 ChapSendResponse(cstate)
 744     chap_state *cstate;
 745 {
 746     u_char *outp;
 747     int outlen, md_len, name_len;
 748
 749     md_len = cstate->resp_length;
 750     name_len = strlen(cstate->resp_name);
 751     outlen = CHAP_HEADERLEN + sizeof (u_char) + md_len + name_len;
 752     outp = outpacket_buf;
 753
 754     MAKEHEADER(outp, PPP_CHAP);
 755
 756     PUTCHAR(CHAP_RESPONSE, outp);       /* we are a response */
 757     PUTCHAR(cstate->resp_id, outp);     /* copy id from challenge packet */
 758     PUTSHORT(outlen, outp);             /* packet length */
 759
 760     PUTCHAR(md_len, outp);              /* length of MD */
 761     BCOPY(cstate->response, outp, md_len);      /* copy MD to buffer */
 762     INCPTR(md_len, outp);
 763
 764     BCOPY(cstate->resp_name, outp, name_len); /* append our name */
 765
 766     /* send the packet */
 767     output(cstate->unit, outpacket_buf, outlen + PPP_HDRLEN);
 768
 769     cstate->clientstate = CHAPCS_RESPONSE;
 770     TIMEOUT(ChapResponseTimeout, (caddr_t) cstate, cstate->timeouttime);
 771     ++cstate->resp_transmits;
 772 }
 773
 774 /*
 775  * ChapPrintPkt - print the contents of a CHAP packet.
 776  */
 777 char *ChapCodenames[] = {
 778     "Challenge", "Response", "Success", "Failure"
 779 };
 780
 781 int
 782 ChapPrintPkt(p, plen, printer, arg)
 783     u_char *p;
 784     int plen;
 785     void (*printer) __P((void *, char *, ...));
 786     void *arg;
 787 {
 788     int code, id, len;
 789     int clen, nlen;
 790     u_char x;
 791
 792     if (plen < CHAP_HEADERLEN)
 793         return 0;
 794     GETCHAR(code, p);
 795     GETCHAR(id, p);
 796     GETSHORT(len, p);
 797     if (len < CHAP_HEADERLEN || len > plen)
 798         return 0;
 799
 800     if (code >= 1 && code <= sizeof(ChapCodenames) / sizeof(char *))
 801         printer(arg, " %s", ChapCodenames[code-1]);
 802     else
 803         printer(arg, " code=0x%x", code);
 804     printer(arg, " id=0x%x", id);
 805     len -= CHAP_HEADERLEN;
 806     switch (code) {
 807     case CHAP_CHALLENGE:
 808     case CHAP_RESPONSE:
 809         if (len < 1)
 810             break;
 811         clen = p[0];
 812         if (len < clen + 1)
 813             break;
 814         ++p;
 815         nlen = len - clen - 1;
 816         printer(arg, " <");
 817         for (; clen > 0; --clen) {
 818             GETCHAR(x, p);
 819             printer(arg, "%.2x", x);
 820         }
 821         printer(arg, ">, name = ");
 822         print_string((char *)p, nlen, printer, arg);
 823         break;
 824     case CHAP_FAILURE:
 825     case CHAP_SUCCESS:
 826         printer(arg, " ");
 827         print_string((char *)p, len, printer, arg);
 828         break;
 829     default:
 830         for (clen = len; clen > 0; --clen) {
 831             GETCHAR(x, p);
 832             printer(arg, " %.2x", x);
 833         }
 834     }
 835
 836     return len + CHAP_HEADERLEN;
 837 }