source: rtems/c/src/libnetworking/pppd/chap.c @ 2f1b930

4.104.114.84.95
Last change on this file since 2f1b930 was 2f1b930, checked in by Joel Sherrill <joel.sherrill@…>, on 08/16/01 at 20:42:09

2001-08-16 Mike Siers <mikes@…>

  • Update of PPPD to 2.3.11 from 2.3.5 and addition of an example application. Mike's notes on the modifications:
    • renamed error() function because of namespace problems
    • removed calls to the exit() funciton
    • removed extra files from the pppd source directory
    • defined pppd task constant values in rtemspppd.h
    • modifyied example code to get actual tick per second value
    • placed the pppd 2.3.11 man page file (pppd.8) into the pppd directory
  • pppd/cbcp.c, pppd/cbcp.h, pppd/main.c, pppd/ppp_tty.c, pppd/pppmain.c, pppd/rtems-ppp.c, pppd/rtems-ppp.c: Deleted.
  • pppd/pppd.8, pppd/rtemsmain.c, pppd/rtemspppd.c, pppd/rtemspppd.h, pppd/sys-rtems.c, pppd/utils.c, pppd/example/Makefile, pppd/example/README, pppd/example/init.c, pppd/example/netconfig.h, pppd/example/ppp.conf, pppd/example/pppdapp.c, pppd/example/system.h: New files.
  • modem/ppp_tty.c, net/if_ppp.h, pppd/Makefile.am, pppd/README, pppd/STATUS, pppd/auth.c, pppd/ccp.c, pppd/ccp.h, pppd/chap.c, pppd/chap.h, pppd/chap_ms.c, pppd/chap_ms.h, pppd/chat.c, pppd/demand.c, pppd/fsm.c, pppd/fsm.h, pppd/ipcp.c, pppd/ipcp.h, pppd/ipxcp.c, pppd/ipxcp.h, pppd/lcp.c, pppd/lcp.h, pppd/magic.c, pppd/magic.h, pppd/options.c, pppd/patchlevel.h, pppd/pathnames.h, pppd/pppd.h, pppd/upap.c, pppd/upap.h: Modified.
  • Property mode set to 100644
File size: 21.1 KB
Line 
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   "$Id$"
37
38/*
39 * TODO:
40 */
41
42#include <stdio.h>
43#include <string.h>
44#include <sys/types.h>
45#include <sys/time.h>
46
47#include "pppd.h"
48#include "chap.h"
49#include "md5.h"
50#ifdef CHAPMS
51#include "chap_ms.h"
52#endif
53
54static const char rcsid[] = RCSID;
55
56/*
57 * Command-line options.
58 */
59static option_t chap_option_list[] = {
60    { "chap-restart", o_int, &chap[0].timeouttime,
61      "Set timeout for CHAP" },
62    { "chap-max-challenge", o_int, &chap[0].max_transmits,
63      "Set max #xmits for challenge" },
64    { "chap-interval", o_int, &chap[0].chal_interval,
65      "Set interval for rechallenge" },
66#ifdef MSLANMAN
67    { "ms-lanman", o_bool, &ms_lanman,
68      "Use LanMan passwd when using MS-CHAP", 1 },
69#endif
70    { NULL }
71};
72
73/*
74 * Protocol entry points.
75 */
76static void ChapInit __P((int));
77static void ChapLowerUp __P((int));
78static void ChapLowerDown __P((int));
79static void ChapInput __P((int, u_char *, int));
80static void ChapProtocolReject __P((int));
81static int  ChapPrintPkt __P((u_char *, int,
82                              void (*) __P((void *, char *, ...)), void *));
83
84struct protent chap_protent = {
85    PPP_CHAP,
86    ChapInit,
87    ChapInput,
88    ChapProtocolReject,
89    ChapLowerUp,
90    ChapLowerDown,
91    NULL,
92    NULL,
93    ChapPrintPkt,
94    NULL,
95    1,
96    "CHAP",
97    NULL,
98    chap_option_list,
99    NULL,
100    NULL,
101    NULL
102};
103
104chap_state chap[NUM_PPP];               /* CHAP state; one for each unit */
105
106static void ChapChallengeTimeout __P((void *));
107static void ChapResponseTimeout __P((void *));
108static void ChapReceiveChallenge __P((chap_state *, u_char *, int, int));
109static void ChapRechallenge __P((void *));
110static void ChapReceiveResponse __P((chap_state *, u_char *, int, int));
111static void ChapReceiveSuccess __P((chap_state *, u_char *, int, int));
112static void ChapReceiveFailure __P((chap_state *, u_char *, int, int));
113static void ChapSendStatus __P((chap_state *, int));
114static void ChapSendChallenge __P((chap_state *));
115static void ChapSendResponse __P((chap_state *));
116static void ChapGenChallenge __P((chap_state *));
117
118extern double drand48 __P((void));
119extern void srand48 __P((long));
120
121/*
122 * ChapInit - Initialize a CHAP unit.
123 */
124static void
125ChapInit(unit)
126    int unit;
127{
128    chap_state *cstate = &chap[unit];
129
130    BZERO(cstate, sizeof(*cstate));
131    cstate->unit = unit;
132    cstate->clientstate = CHAPCS_INITIAL;
133    cstate->serverstate = CHAPSS_INITIAL;
134    cstate->timeouttime = CHAP_DEFTIMEOUT;
135    cstate->max_transmits = CHAP_DEFTRANSMITS;
136    /* random number generator is initialized in magic_init */
137}
138
139
140/*
141 * ChapAuthWithPeer - Authenticate us with our peer (start client).
142 *
143 */
144void
145ChapAuthWithPeer(unit, our_name, digest)
146    int unit;
147    char *our_name;
148    int digest;
149{
150    chap_state *cstate = &chap[unit];
151
152    cstate->resp_name = our_name;
153    cstate->resp_type = digest;
154
155    if (cstate->clientstate == CHAPCS_INITIAL ||
156        cstate->clientstate == CHAPCS_PENDING) {
157        /* lower layer isn't up - wait until later */
158        cstate->clientstate = CHAPCS_PENDING;
159        return;
160    }
161
162    /*
163     * We get here as a result of LCP coming up.
164     * So even if CHAP was open before, we will
165     * have to re-authenticate ourselves.
166     */
167    cstate->clientstate = CHAPCS_LISTEN;
168}
169
170
171/*
172 * ChapAuthPeer - Authenticate our peer (start server).
173 */
174void
175ChapAuthPeer(unit, our_name, digest)
176    int unit;
177    char *our_name;
178    int digest;
179{
180    chap_state *cstate = &chap[unit];
181 
182    cstate->chal_name = our_name;
183    cstate->chal_type = digest;
184
185    if (cstate->serverstate == CHAPSS_INITIAL ||
186        cstate->serverstate == CHAPSS_PENDING) {
187        /* lower layer isn't up - wait until later */
188        cstate->serverstate = CHAPSS_PENDING;
189        return;
190    }
191
192    ChapGenChallenge(cstate);
193    ChapSendChallenge(cstate);          /* crank it up dude! */
194    cstate->serverstate = CHAPSS_INITIAL_CHAL;
195}
196
197
198/*
199 * ChapChallengeTimeout - Timeout expired on sending challenge.
200 */
201static void
202ChapChallengeTimeout(arg)
203    void *arg;
204{
205    chap_state *cstate = (chap_state *) arg;
206 
207    /* if we aren't sending challenges, don't worry.  then again we */
208    /* probably shouldn't be here either */
209    if (cstate->serverstate != CHAPSS_INITIAL_CHAL &&
210        cstate->serverstate != CHAPSS_RECHALLENGE)
211        return;
212
213    if (cstate->chal_transmits >= cstate->max_transmits) {
214        /* give up on peer */
215        error("Peer failed to respond to CHAP challenge");
216        cstate->serverstate = CHAPSS_BADAUTH;
217        auth_peer_fail(cstate->unit, PPP_CHAP);
218        return;
219    }
220
221    ChapSendChallenge(cstate);          /* Re-send challenge */
222}
223
224
225/*
226 * ChapResponseTimeout - Timeout expired on sending response.
227 */
228static void
229ChapResponseTimeout(arg)
230    void *arg;
231{
232    chap_state *cstate = (chap_state *) arg;
233
234    /* if we aren't sending a response, don't worry. */
235    if (cstate->clientstate != CHAPCS_RESPONSE)
236        return;
237
238    ChapSendResponse(cstate);           /* re-send response */
239}
240
241
242/*
243 * ChapRechallenge - Time to challenge the peer again.
244 */
245static void
246ChapRechallenge(arg)
247    void *arg;
248{
249    chap_state *cstate = (chap_state *) arg;
250
251    /* if we aren't sending a response, don't worry. */
252    if (cstate->serverstate != CHAPSS_OPEN)
253        return;
254
255    ChapGenChallenge(cstate);
256    ChapSendChallenge(cstate);
257    cstate->serverstate = CHAPSS_RECHALLENGE;
258}
259
260
261/*
262 * ChapLowerUp - The lower layer is up.
263 *
264 * Start up if we have pending requests.
265 */
266static void
267ChapLowerUp(unit)
268    int unit;
269{
270    chap_state *cstate = &chap[unit];
271 
272    if (cstate->clientstate == CHAPCS_INITIAL)
273        cstate->clientstate = CHAPCS_CLOSED;
274    else if (cstate->clientstate == CHAPCS_PENDING)
275        cstate->clientstate = CHAPCS_LISTEN;
276
277    if (cstate->serverstate == CHAPSS_INITIAL)
278        cstate->serverstate = CHAPSS_CLOSED;
279    else if (cstate->serverstate == CHAPSS_PENDING) {
280        ChapGenChallenge(cstate);
281        ChapSendChallenge(cstate);
282        cstate->serverstate = CHAPSS_INITIAL_CHAL;
283    }
284}
285
286
287/*
288 * ChapLowerDown - The lower layer is down.
289 *
290 * Cancel all timeouts.
291 */
292static void
293ChapLowerDown(unit)
294    int unit;
295{
296    chap_state *cstate = &chap[unit];
297 
298    /* Timeout(s) pending?  Cancel if so. */
299    if (cstate->serverstate == CHAPSS_INITIAL_CHAL ||
300        cstate->serverstate == CHAPSS_RECHALLENGE)
301        UNTIMEOUT(ChapChallengeTimeout, cstate);
302    else if (cstate->serverstate == CHAPSS_OPEN
303             && cstate->chal_interval != 0)
304        UNTIMEOUT(ChapRechallenge, cstate);
305    if (cstate->clientstate == CHAPCS_RESPONSE)
306        UNTIMEOUT(ChapResponseTimeout, cstate);
307
308    cstate->clientstate = CHAPCS_INITIAL;
309    cstate->serverstate = CHAPSS_INITIAL;
310}
311
312
313/*
314 * ChapProtocolReject - Peer doesn't grok CHAP.
315 */
316static void
317ChapProtocolReject(unit)
318    int unit;
319{
320    chap_state *cstate = &chap[unit];
321
322    if (cstate->serverstate != CHAPSS_INITIAL &&
323        cstate->serverstate != CHAPSS_CLOSED)
324        auth_peer_fail(unit, PPP_CHAP);
325    if (cstate->clientstate != CHAPCS_INITIAL &&
326        cstate->clientstate != CHAPCS_CLOSED)
327        auth_withpeer_fail(unit, PPP_CHAP);
328    ChapLowerDown(unit);                /* shutdown chap */
329}
330
331
332/*
333 * ChapInput - Input CHAP packet.
334 */
335static void
336ChapInput(unit, inpacket, packet_len)
337    int unit;
338    u_char *inpacket;
339    int packet_len;
340{
341    chap_state *cstate = &chap[unit];
342    u_char *inp;
343    u_char code, id;
344    int len;
345 
346    /*
347     * Parse header (code, id and length).
348     * If packet too short, drop it.
349     */
350    inp = inpacket;
351    if (packet_len < CHAP_HEADERLEN) {
352        CHAPDEBUG(("ChapInput: rcvd short header."));
353        return;
354    }
355    GETCHAR(code, inp);
356    GETCHAR(id, inp);
357    GETSHORT(len, inp);
358    if (len < CHAP_HEADERLEN) {
359        CHAPDEBUG(("ChapInput: rcvd illegal length."));
360        return;
361    }
362    if (len > packet_len) {
363        CHAPDEBUG(("ChapInput: rcvd short packet."));
364        return;
365    }
366    len -= CHAP_HEADERLEN;
367 
368    /*
369     * Action depends on code (as in fact it usually does :-).
370     */
371    switch (code) {
372    case CHAP_CHALLENGE:
373        ChapReceiveChallenge(cstate, inp, id, len);
374        break;
375   
376    case CHAP_RESPONSE:
377        ChapReceiveResponse(cstate, inp, id, len);
378        break;
379   
380    case CHAP_FAILURE:
381        ChapReceiveFailure(cstate, inp, id, len);
382        break;
383
384    case CHAP_SUCCESS:
385        ChapReceiveSuccess(cstate, inp, id, len);
386        break;
387
388    default:                            /* Need code reject? */
389        warn("Unknown CHAP code (%d) received.", code);
390        break;
391    }
392}
393
394
395/*
396 * ChapReceiveChallenge - Receive Challenge and send Response.
397 */
398static void
399ChapReceiveChallenge(cstate, inp, id, len)
400    chap_state *cstate;
401    u_char *inp;
402    int id;
403    int len;
404{
405    int rchallenge_len;
406    u_char *rchallenge;
407    int secret_len;
408    char secret[MAXSECRETLEN];
409    char rhostname[256];
410    MD5_CTX mdContext;
411    u_char hash[MD5_SIGNATURE_SIZE];
412 
413    if (cstate->clientstate == CHAPCS_CLOSED ||
414        cstate->clientstate == CHAPCS_PENDING) {
415        CHAPDEBUG(("ChapReceiveChallenge: in state %d", cstate->clientstate));
416        return;
417    }
418
419    if (len < 2) {
420        CHAPDEBUG(("ChapReceiveChallenge: rcvd short packet."));
421        return;
422    }
423
424    GETCHAR(rchallenge_len, inp);
425    len -= sizeof (u_char) + rchallenge_len;    /* now name field length */
426    if (len < 0) {
427        CHAPDEBUG(("ChapReceiveChallenge: rcvd short packet."));
428        return;
429    }
430    rchallenge = inp;
431    INCPTR(rchallenge_len, inp);
432
433    if (len >= sizeof(rhostname))
434        len = sizeof(rhostname) - 1;
435    BCOPY(inp, rhostname, len);
436    rhostname[len] = '\000';
437
438    /* Microsoft doesn't send their name back in the PPP packet */
439    if (explicit_remote || (remote_name[0] != 0 && rhostname[0] == 0)) {
440        strlcpy(rhostname, remote_name, sizeof(rhostname));
441        CHAPDEBUG(("ChapReceiveChallenge: using '%q' as remote name",
442                   rhostname));
443    }
444
445    /* get secret for authenticating ourselves with the specified host */
446    if (!get_secret(cstate->unit, cstate->resp_name, rhostname,
447                    secret, &secret_len, 0)) {
448        secret_len = 0;         /* assume null secret if can't find one */
449        warn("No CHAP secret found for authenticating us to %q", rhostname);
450    }
451
452    /* cancel response send timeout if necessary */
453    if (cstate->clientstate == CHAPCS_RESPONSE)
454        UNTIMEOUT(ChapResponseTimeout, cstate);
455
456    cstate->resp_id = id;
457    cstate->resp_transmits = 0;
458
459    /*  generate MD based on negotiated type */
460    switch (cstate->resp_type) {
461
462    case CHAP_DIGEST_MD5:
463        MD5Init(&mdContext);
464        MD5Update(&mdContext, &cstate->resp_id, 1);
465        MD5Update(&mdContext, secret, secret_len);
466        MD5Update(&mdContext, rchallenge, rchallenge_len);
467        MD5Final(hash, &mdContext);
468        BCOPY(hash, cstate->response, MD5_SIGNATURE_SIZE);
469        cstate->resp_length = MD5_SIGNATURE_SIZE;
470        break;
471
472#ifdef CHAPMS
473    case CHAP_MICROSOFT:
474        ChapMS(cstate, rchallenge, rchallenge_len, secret, secret_len);
475        break;
476#endif
477
478    default:
479        CHAPDEBUG(("unknown digest type %d", cstate->resp_type));
480        return;
481    }
482
483    BZERO(secret, sizeof(secret));
484    ChapSendResponse(cstate);
485}
486
487
488/*
489 * ChapReceiveResponse - Receive and process response.
490 */
491static void
492ChapReceiveResponse(cstate, inp, id, len)
493    chap_state *cstate;
494    u_char *inp;
495    int id;
496    int len;
497{
498    u_char *remmd, remmd_len;
499    int secret_len, old_state;
500    int code;
501    char rhostname[256];
502    MD5_CTX mdContext;
503    char secret[MAXSECRETLEN];
504    u_char hash[MD5_SIGNATURE_SIZE];
505
506    if (cstate->serverstate == CHAPSS_CLOSED ||
507        cstate->serverstate == CHAPSS_PENDING) {
508        CHAPDEBUG(("ChapReceiveResponse: in state %d", cstate->serverstate));
509        return;
510    }
511
512    if (id != cstate->chal_id)
513        return;                 /* doesn't match ID of last challenge */
514
515    /*
516     * If we have received a duplicate or bogus Response,
517     * we have to send the same answer (Success/Failure)
518     * as we did for the first Response we saw.
519     */
520    if (cstate->serverstate == CHAPSS_OPEN) {
521        ChapSendStatus(cstate, CHAP_SUCCESS);
522        return;
523    }
524    if (cstate->serverstate == CHAPSS_BADAUTH) {
525        ChapSendStatus(cstate, CHAP_FAILURE);
526        return;
527    }
528
529    if (len < 2) {
530        CHAPDEBUG(("ChapReceiveResponse: rcvd short packet."));
531        return;
532    }
533    GETCHAR(remmd_len, inp);            /* get length of MD */
534    remmd = inp;                        /* get pointer to MD */
535    INCPTR(remmd_len, inp);
536
537    len -= sizeof (u_char) + remmd_len;
538    if (len < 0) {
539        CHAPDEBUG(("ChapReceiveResponse: rcvd short packet."));
540        return;
541    }
542
543    UNTIMEOUT(ChapChallengeTimeout, cstate);
544
545    if (len >= sizeof(rhostname))
546        len = sizeof(rhostname) - 1;
547    BCOPY(inp, rhostname, len);
548    rhostname[len] = '\000';
549
550    /*
551     * Get secret for authenticating them with us,
552     * do the hash ourselves, and compare the result.
553     */
554    code = CHAP_FAILURE;
555    if (!get_secret(cstate->unit, (explicit_remote? remote_name: rhostname),
556                    cstate->chal_name, secret, &secret_len, 1)) {
557        warn("No CHAP secret found for authenticating %q", rhostname);
558    } else {
559
560        /*  generate MD based on negotiated type */
561        switch (cstate->chal_type) {
562
563        case CHAP_DIGEST_MD5:           /* only MD5 is defined for now */
564            if (remmd_len != MD5_SIGNATURE_SIZE)
565                break;                  /* it's not even the right length */
566            MD5Init(&mdContext);
567            MD5Update(&mdContext, &cstate->chal_id, 1);
568            MD5Update(&mdContext, secret, secret_len);
569            MD5Update(&mdContext, cstate->challenge, cstate->chal_len);
570            MD5Final(hash, &mdContext);
571
572            /* compare local and remote MDs and send the appropriate status */
573            if (memcmp (hash, remmd, MD5_SIGNATURE_SIZE) == 0)
574                code = CHAP_SUCCESS;    /* they are the same! */
575            break;
576
577        default:
578            CHAPDEBUG(("unknown digest type %d", cstate->chal_type));
579        }
580    }
581
582    BZERO(secret, sizeof(secret));
583    ChapSendStatus(cstate, code);
584
585    if (code == CHAP_SUCCESS) {
586        old_state = cstate->serverstate;
587        cstate->serverstate = CHAPSS_OPEN;
588        if (old_state == CHAPSS_INITIAL_CHAL) {
589            auth_peer_success(cstate->unit, PPP_CHAP, rhostname, len);
590        }
591        if (cstate->chal_interval != 0)
592            TIMEOUT(ChapRechallenge, cstate, cstate->chal_interval);
593        notice("CHAP peer authentication succeeded for %q", rhostname);
594
595    } else {
596        error("CHAP peer authentication failed for remote host %q", rhostname);
597        cstate->serverstate = CHAPSS_BADAUTH;
598        auth_peer_fail(cstate->unit, PPP_CHAP);
599    }
600}
601
602/*
603 * ChapReceiveSuccess - Receive Success
604 */
605static void
606ChapReceiveSuccess(cstate, inp, id, len)
607    chap_state *cstate;
608    u_char *inp;
609    u_char id;
610    int len;
611{
612
613    if (cstate->clientstate == CHAPCS_OPEN)
614        /* presumably an answer to a duplicate response */
615        return;
616
617    if (cstate->clientstate != CHAPCS_RESPONSE) {
618        /* don't know what this is */
619        CHAPDEBUG(("ChapReceiveSuccess: in state %d\n", cstate->clientstate));
620        return;
621    }
622
623    UNTIMEOUT(ChapResponseTimeout, cstate);
624
625    /*
626     * Print message.
627     */
628    if (len > 0)
629        PRINTMSG(inp, len);
630
631    cstate->clientstate = CHAPCS_OPEN;
632
633    auth_withpeer_success(cstate->unit, PPP_CHAP);
634}
635
636
637/*
638 * ChapReceiveFailure - Receive failure.
639 */
640static void
641ChapReceiveFailure(cstate, inp, id, len)
642    chap_state *cstate;
643    u_char *inp;
644    u_char id;
645    int len;
646{
647    if (cstate->clientstate != CHAPCS_RESPONSE) {
648        /* don't know what this is */
649        CHAPDEBUG(("ChapReceiveFailure: in state %d\n", cstate->clientstate));
650        return;
651    }
652
653    UNTIMEOUT(ChapResponseTimeout, cstate);
654
655    /*
656     * Print message.
657     */
658    if (len > 0)
659        PRINTMSG(inp, len);
660
661    error("CHAP authentication failed");
662    auth_withpeer_fail(cstate->unit, PPP_CHAP);
663}
664
665
666/*
667 * ChapSendChallenge - Send an Authenticate challenge.
668 */
669static void
670ChapSendChallenge(cstate)
671    chap_state *cstate;
672{
673    u_char *outp;
674    int chal_len, name_len;
675    int outlen;
676
677    chal_len = cstate->chal_len;
678    name_len = strlen(cstate->chal_name);
679    outlen = CHAP_HEADERLEN + sizeof (u_char) + chal_len + name_len;
680    outp = outpacket_buf;
681
682    MAKEHEADER(outp, PPP_CHAP);         /* paste in a CHAP header */
683
684    PUTCHAR(CHAP_CHALLENGE, outp);
685    PUTCHAR(cstate->chal_id, outp);
686    PUTSHORT(outlen, outp);
687
688    PUTCHAR(chal_len, outp);            /* put length of challenge */
689    BCOPY(cstate->challenge, outp, chal_len);
690    INCPTR(chal_len, outp);
691
692    BCOPY(cstate->chal_name, outp, name_len);   /* append hostname */
693
694    output(cstate->unit, outpacket_buf, outlen + PPP_HDRLEN);
695 
696    TIMEOUT(ChapChallengeTimeout, cstate, cstate->timeouttime);
697    ++cstate->chal_transmits;
698}
699
700
701/*
702 * ChapSendStatus - Send a status response (ack or nak).
703 */
704static void
705ChapSendStatus(cstate, code)
706    chap_state *cstate;
707    int code;
708{
709    u_char *outp;
710    int outlen, msglen;
711    char msg[256];
712
713    if (code == CHAP_SUCCESS)
714        slprintf(msg, sizeof(msg), "Welcome to %s.", hostname);
715    else
716        slprintf(msg, sizeof(msg), "I don't like you.  Go 'way.");
717    msglen = strlen(msg);
718
719    outlen = CHAP_HEADERLEN + msglen;
720    outp = outpacket_buf;
721
722    MAKEHEADER(outp, PPP_CHAP); /* paste in a header */
723 
724    PUTCHAR(code, outp);
725    PUTCHAR(cstate->chal_id, outp);
726    PUTSHORT(outlen, outp);
727    BCOPY(msg, outp, msglen);
728    output(cstate->unit, outpacket_buf, outlen + PPP_HDRLEN);
729}
730
731/*
732 * ChapGenChallenge is used to generate a pseudo-random challenge string of
733 * a pseudo-random length between min_len and max_len.  The challenge
734 * string and its length are stored in *cstate, and various other fields of
735 * *cstate are initialized.
736 */
737
738static void
739ChapGenChallenge(cstate)
740    chap_state *cstate;
741{
742    int chal_len;
743    u_char *ptr = cstate->challenge;
744    int i;
745
746    /* pick a random challenge length between MIN_CHALLENGE_LENGTH and
747       MAX_CHALLENGE_LENGTH */ 
748    chal_len =  (unsigned) ((drand48() *
749                             (MAX_CHALLENGE_LENGTH - MIN_CHALLENGE_LENGTH)) +
750                            MIN_CHALLENGE_LENGTH);
751    cstate->chal_len = chal_len;
752    cstate->chal_id = ++cstate->id;
753    cstate->chal_transmits = 0;
754
755    /* generate a random string */
756    for (i = 0; i < chal_len; i++)
757        *ptr++ = (char) (drand48() * 0xff);
758}
759
760/*
761 * ChapSendResponse - send a response packet with values as specified
762 * in *cstate.
763 */
764/* ARGSUSED */
765static void
766ChapSendResponse(cstate)
767    chap_state *cstate;
768{
769    u_char *outp;
770    int outlen, md_len, name_len;
771
772    md_len = cstate->resp_length;
773    name_len = strlen(cstate->resp_name);
774    outlen = CHAP_HEADERLEN + sizeof (u_char) + md_len + name_len;
775    outp = outpacket_buf;
776
777    MAKEHEADER(outp, PPP_CHAP);
778
779    PUTCHAR(CHAP_RESPONSE, outp);       /* we are a response */
780    PUTCHAR(cstate->resp_id, outp);     /* copy id from challenge packet */
781    PUTSHORT(outlen, outp);             /* packet length */
782
783    PUTCHAR(md_len, outp);              /* length of MD */
784    BCOPY(cstate->response, outp, md_len);      /* copy MD to buffer */
785    INCPTR(md_len, outp);
786
787    BCOPY(cstate->resp_name, outp, name_len); /* append our name */
788
789    /* send the packet */
790    output(cstate->unit, outpacket_buf, outlen + PPP_HDRLEN);
791
792    cstate->clientstate = CHAPCS_RESPONSE;
793    TIMEOUT(ChapResponseTimeout, cstate, cstate->timeouttime);
794    ++cstate->resp_transmits;
795}
796
797/*
798 * ChapPrintPkt - print the contents of a CHAP packet.
799 */
800static char *ChapCodenames[] = {
801    "Challenge", "Response", "Success", "Failure"
802};
803
804static int
805ChapPrintPkt(p, plen, printer, arg)
806    u_char *p;
807    int plen;
808    void (*printer) __P((void *, char *, ...));
809    void *arg;
810{
811    int code, id, len;
812    int clen, nlen;
813    u_char x;
814
815    if (plen < CHAP_HEADERLEN)
816        return 0;
817    GETCHAR(code, p);
818    GETCHAR(id, p);
819    GETSHORT(len, p);
820    if (len < CHAP_HEADERLEN || len > plen)
821        return 0;
822
823    if (code >= 1 && code <= sizeof(ChapCodenames) / sizeof(char *))
824        printer(arg, " %s", ChapCodenames[code-1]);
825    else
826        printer(arg, " code=0x%x", code);
827    printer(arg, " id=0x%x", id);
828    len -= CHAP_HEADERLEN;
829    switch (code) {
830    case CHAP_CHALLENGE:
831    case CHAP_RESPONSE:
832        if (len < 1)
833            break;
834        clen = p[0];
835        if (len < clen + 1)
836            break;
837        ++p;
838        nlen = len - clen - 1;
839        printer(arg, " <");
840        for (; clen > 0; --clen) {
841            GETCHAR(x, p);
842            printer(arg, "%.2x", x);
843        }
844        printer(arg, ">, name = ");
845        print_string((char *)p, nlen, printer, arg);
846        break;
847    case CHAP_FAILURE:
848    case CHAP_SUCCESS:
849        printer(arg, " ");
850        print_string((char *)p, len, printer, arg);
851        break;
852    default:
853        for (clen = len; clen > 0; --clen) {
854            GETCHAR(x, p);
855            printer(arg, " %.2x", x);
856        }
857    }
858
859    return len + CHAP_HEADERLEN;
860}
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