xref: /freebsd/usr.sbin/ppp/chap.c (revision 5521ff5a4d1929056e7ffc982fac3341ca54df7c)
1 /*-
2  * Copyright (c) 1996 - 2001 Brian Somers <brian@Awfulhak.org>
3  *          based on work by Toshiharu OHNO <tony-o@iij.ad.jp>
4  *                           Internet Initiative Japan, Inc (IIJ)
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26  * SUCH DAMAGE.
27  *
28  * $FreeBSD$
29  */
30 
31 #include <sys/param.h>
32 #include <netinet/in.h>
33 #include <netinet/in_systm.h>
34 #include <netinet/ip.h>
35 #include <sys/un.h>
36 
37 #include <errno.h>
38 #include <fcntl.h>
39 #ifdef HAVE_DES
40 #include <md4.h>
41 #endif
42 #include <md5.h>
43 #include <paths.h>
44 #include <signal.h>
45 #include <stdio.h>
46 #include <stdlib.h>
47 #include <string.h>
48 #include <sys/wait.h>
49 #include <termios.h>
50 #include <unistd.h>
51 
52 #include "layer.h"
53 #include "mbuf.h"
54 #include "log.h"
55 #include "defs.h"
56 #include "timer.h"
57 #include "fsm.h"
58 #include "proto.h"
59 #include "lqr.h"
60 #include "hdlc.h"
61 #include "lcp.h"
62 #include "auth.h"
63 #include "async.h"
64 #include "throughput.h"
65 #include "descriptor.h"
66 #include "chap.h"
67 #include "iplist.h"
68 #include "slcompress.h"
69 #include "ipcp.h"
70 #include "filter.h"
71 #include "ccp.h"
72 #include "link.h"
73 #include "physical.h"
74 #include "mp.h"
75 #ifndef NORADIUS
76 #include "radius.h"
77 #endif
78 #include "bundle.h"
79 #include "chat.h"
80 #include "cbcp.h"
81 #include "command.h"
82 #include "datalink.h"
83 #ifdef HAVE_DES
84 #include "chap_ms.h"
85 #include "mppe.h"
86 #endif
87 #include "id.h"
88 
89 static const char * const chapcodes[] = {
90   "???", "CHALLENGE", "RESPONSE", "SUCCESS", "FAILURE"
91 };
92 #define MAXCHAPCODE (sizeof chapcodes / sizeof chapcodes[0] - 1)
93 
94 static void
95 ChapOutput(struct physical *physical, u_int code, u_int id,
96 	   const u_char *ptr, int count, const char *text)
97 {
98   int plen;
99   struct fsmheader lh;
100   struct mbuf *bp;
101 
102   plen = sizeof(struct fsmheader) + count;
103   lh.code = code;
104   lh.id = id;
105   lh.length = htons(plen);
106   bp = m_get(plen, MB_CHAPOUT);
107   memcpy(MBUF_CTOP(bp), &lh, sizeof(struct fsmheader));
108   if (count)
109     memcpy(MBUF_CTOP(bp) + sizeof(struct fsmheader), ptr, count);
110   log_DumpBp(LogDEBUG, "ChapOutput", bp);
111   if (text == NULL)
112     log_Printf(LogPHASE, "Chap Output: %s\n", chapcodes[code]);
113   else
114     log_Printf(LogPHASE, "Chap Output: %s (%s)\n", chapcodes[code], text);
115   link_PushPacket(&physical->link, bp, physical->dl->bundle,
116                   LINK_QUEUES(&physical->link) - 1, PROTO_CHAP);
117 }
118 
119 static char *
120 chap_BuildAnswer(char *name, char *key, u_char id, char *challenge, u_char type
121 #ifdef HAVE_DES
122                  , char *peerchallenge, char *authresponse, int lanman
123 #endif
124                 )
125 {
126   char *result, *digest;
127   size_t nlen, klen;
128 
129   nlen = strlen(name);
130   klen = strlen(key);
131 
132 #ifdef HAVE_DES
133   if (type == 0x80) {
134     char expkey[AUTHLEN << 2];
135     MD4_CTX MD4context;
136     int f;
137 
138     if ((result = malloc(1 + nlen + MS_CHAP_RESPONSE_LEN)) == NULL)
139       return result;
140 
141     digest = result;					/* the response */
142     *digest++ = MS_CHAP_RESPONSE_LEN;			/* 49 */
143     memcpy(digest + MS_CHAP_RESPONSE_LEN, name, nlen);
144     if (lanman) {
145       memset(digest + 24, '\0', 25);
146       mschap_LANMan(digest, challenge + 1, key);	/* LANMan response */
147     } else {
148       memset(digest, '\0', 25);
149       digest += 24;
150 
151       for (f = 0; f < klen; f++) {
152         expkey[2*f] = key[f];
153         expkey[2*f+1] = '\0';
154       }
155       /*
156        *           -----------
157        * expkey = | k\0e\0y\0 |
158        *           -----------
159        */
160       MD4Init(&MD4context);
161       MD4Update(&MD4context, expkey, klen << 1);
162       MD4Final(digest, &MD4context);
163 
164       /*
165        *           ---- -------- ---------------- ------- ------
166        * result = | 49 | LANMan | 16 byte digest | 9 * ? | name |
167        *           ---- -------- ---------------- ------- ------
168        */
169       mschap_NT(digest, challenge + 1);
170     }
171     /*
172      *           ---- -------- ------------- ----- ------
173      *          |    |  struct MS_ChapResponse24  |      |
174      * result = | 49 | LANMan  |  NT digest | 0/1 | name |
175      *           ---- -------- ------------- ----- ------
176      * where only one of LANMan & NT digest are set.
177      */
178   } else if (type == 0x81) {
179     char expkey[AUTHLEN << 2];
180     char pwdhash[CHAP81_HASH_LEN];
181     char pwdhashhash[CHAP81_HASH_LEN];
182     char *ntresponse;
183     int f;
184 
185     if ((result = malloc(1 + nlen + CHAP81_RESPONSE_LEN)) == NULL)
186       return result;
187 
188     memset(result, 0, 1 + nlen + CHAP81_RESPONSE_LEN);
189 
190     digest = result;
191     *digest++ = CHAP81_RESPONSE_LEN;		/* value size */
192 
193     /* Copy our challenge */
194     memcpy(digest, peerchallenge + 1, CHAP81_CHALLENGE_LEN);
195 
196     /* Expand password to Unicode XXX */
197     for (f = 0; f < klen; f++) {
198       expkey[2*f] = key[f];
199       expkey[2*f+1] = '\0';
200     }
201 
202     ntresponse = digest + CHAP81_NTRESPONSE_OFF;
203 
204     /* Get some needed hashes */
205     NtPasswordHash(expkey, klen * 2, pwdhash);
206     HashNtPasswordHash(pwdhash, pwdhashhash);
207 
208     /* Generate NTRESPONSE to respond on challenge call */
209     GenerateNTResponse(challenge + 1, peerchallenge + 1, name, nlen,
210                        expkey, klen * 2, ntresponse);
211 
212     /* Generate MPPE MASTERKEY */
213     GetMasterKey(pwdhashhash, ntresponse, MPPE_MasterKey);    /* XXX Global ! */
214 
215     /* Generate AUTHRESPONSE to verify on auth success */
216     GenerateAuthenticatorResponse(expkey, klen * 2, ntresponse,
217                                   peerchallenge + 1, challenge + 1, name, nlen,
218                                   authresponse);
219 
220     authresponse[CHAP81_AUTHRESPONSE_LEN] = 0;
221 
222     memcpy(digest + CHAP81_RESPONSE_LEN, name, nlen);
223   } else
224 #endif
225   if ((result = malloc(nlen + 17)) != NULL) {
226     /* Normal MD5 stuff */
227     MD5_CTX MD5context;
228 
229     digest = result;
230     *digest++ = 16;				/* value size */
231 
232     MD5Init(&MD5context);
233     MD5Update(&MD5context, &id, 1);
234     MD5Update(&MD5context, key, klen);
235     MD5Update(&MD5context, challenge + 1, *challenge);
236     MD5Final(digest, &MD5context);
237 
238     memcpy(digest + 16, name, nlen);
239     /*
240      *           ---- -------- ------
241      * result = | 16 | digest | name |
242      *           ---- -------- ------
243      */
244   }
245 
246   return result;
247 }
248 
249 static void
250 chap_StartChild(struct chap *chap, char *prog, const char *name)
251 {
252   char *argv[MAXARGS], *nargv[MAXARGS];
253   int argc, fd;
254   int in[2], out[2];
255   pid_t pid;
256 
257   if (chap->child.fd != -1) {
258     log_Printf(LogWARN, "Chap: %s: Program already running\n", prog);
259     return;
260   }
261 
262   if (pipe(in) == -1) {
263     log_Printf(LogERROR, "Chap: pipe: %s\n", strerror(errno));
264     return;
265   }
266 
267   if (pipe(out) == -1) {
268     log_Printf(LogERROR, "Chap: pipe: %s\n", strerror(errno));
269     close(in[0]);
270     close(in[1]);
271     return;
272   }
273 
274   pid = getpid();
275   switch ((chap->child.pid = fork())) {
276     case -1:
277       log_Printf(LogERROR, "Chap: fork: %s\n", strerror(errno));
278       close(in[0]);
279       close(in[1]);
280       close(out[0]);
281       close(out[1]);
282       chap->child.pid = 0;
283       return;
284 
285     case 0:
286       timer_TermService();
287 
288       if ((argc = command_Interpret(prog, strlen(prog), argv)) <= 0) {
289         if (argc < 0) {
290           log_Printf(LogWARN, "CHAP: Invalid command syntax\n");
291           _exit(255);
292         }
293         _exit(0);
294       }
295 
296       close(in[1]);
297       close(out[0]);
298       if (out[1] == STDIN_FILENO)
299         out[1] = dup(out[1]);
300       dup2(in[0], STDIN_FILENO);
301       dup2(out[1], STDOUT_FILENO);
302       close(STDERR_FILENO);
303       if (open(_PATH_DEVNULL, O_RDWR) != STDERR_FILENO) {
304         log_Printf(LogALERT, "Chap: Failed to open %s: %s\n",
305                   _PATH_DEVNULL, strerror(errno));
306         exit(1);
307       }
308       for (fd = getdtablesize(); fd > STDERR_FILENO; fd--)
309         fcntl(fd, F_SETFD, 1);
310 #ifndef NOSUID
311       setuid(ID0realuid());
312 #endif
313       command_Expand(nargv, argc, (char const *const *)argv,
314                      chap->auth.physical->dl->bundle, 0, pid);
315       execvp(nargv[0], nargv);
316       printf("exec() of %s failed: %s\n", nargv[0], strerror(errno));
317       _exit(255);
318 
319     default:
320       close(in[0]);
321       close(out[1]);
322       chap->child.fd = out[0];
323       chap->child.buf.len = 0;
324       write(in[1], chap->auth.in.name, strlen(chap->auth.in.name));
325       write(in[1], "\n", 1);
326       write(in[1], chap->challenge.peer + 1, *chap->challenge.peer);
327       write(in[1], "\n", 1);
328       write(in[1], name, strlen(name));
329       write(in[1], "\n", 1);
330       close(in[1]);
331       break;
332   }
333 }
334 
335 static void
336 chap_Cleanup(struct chap *chap, int sig)
337 {
338   if (chap->child.pid) {
339     int status;
340 
341     close(chap->child.fd);
342     chap->child.fd = -1;
343     if (sig)
344       kill(chap->child.pid, SIGTERM);
345     chap->child.pid = 0;
346     chap->child.buf.len = 0;
347 
348     if (wait(&status) == -1)
349       log_Printf(LogERROR, "Chap: wait: %s\n", strerror(errno));
350     else if (WIFSIGNALED(status))
351       log_Printf(LogWARN, "Chap: Child received signal %d\n", WTERMSIG(status));
352     else if (WIFEXITED(status) && WEXITSTATUS(status))
353       log_Printf(LogERROR, "Chap: Child exited %d\n", WEXITSTATUS(status));
354   }
355   *chap->challenge.local = *chap->challenge.peer = '\0';
356 #ifdef HAVE_DES
357   chap->peertries = 0;
358 #endif
359 }
360 
361 static void
362 chap_Respond(struct chap *chap, char *name, char *key, u_char type
363 #ifdef HAVE_DES
364              , int lm
365 #endif
366             )
367 {
368   u_char *ans;
369 
370   ans = chap_BuildAnswer(name, key, chap->auth.id, chap->challenge.peer, type
371 #ifdef HAVE_DES
372                          , chap->challenge.local, chap->authresponse, lm
373 #endif
374                         );
375 
376   if (ans) {
377     ChapOutput(chap->auth.physical, CHAP_RESPONSE, chap->auth.id,
378                ans, *ans + 1 + strlen(name), name);
379 #ifdef HAVE_DES
380     chap->NTRespSent = !lm;
381     MPPE_IsServer = 0;		/* XXX Global ! */
382 #endif
383     free(ans);
384   } else
385     ChapOutput(chap->auth.physical, CHAP_FAILURE, chap->auth.id,
386                "Out of memory!", 14, NULL);
387 }
388 
389 static int
390 chap_UpdateSet(struct fdescriptor *d, fd_set *r, fd_set *w, fd_set *e, int *n)
391 {
392   struct chap *chap = descriptor2chap(d);
393 
394   if (r && chap && chap->child.fd != -1) {
395     FD_SET(chap->child.fd, r);
396     if (*n < chap->child.fd + 1)
397       *n = chap->child.fd + 1;
398     log_Printf(LogTIMER, "Chap: fdset(r) %d\n", chap->child.fd);
399     return 1;
400   }
401 
402   return 0;
403 }
404 
405 static int
406 chap_IsSet(struct fdescriptor *d, const fd_set *fdset)
407 {
408   struct chap *chap = descriptor2chap(d);
409 
410   return chap && chap->child.fd != -1 && FD_ISSET(chap->child.fd, fdset);
411 }
412 
413 static void
414 chap_Read(struct fdescriptor *d, struct bundle *bundle, const fd_set *fdset)
415 {
416   struct chap *chap = descriptor2chap(d);
417   int got;
418 
419   got = read(chap->child.fd, chap->child.buf.ptr + chap->child.buf.len,
420              sizeof chap->child.buf.ptr - chap->child.buf.len - 1);
421   if (got == -1) {
422     log_Printf(LogERROR, "Chap: Read: %s\n", strerror(errno));
423     chap_Cleanup(chap, SIGTERM);
424   } else if (got == 0) {
425     log_Printf(LogWARN, "Chap: Read: Child terminated connection\n");
426     chap_Cleanup(chap, SIGTERM);
427   } else {
428     char *name, *key, *end;
429 
430     chap->child.buf.len += got;
431     chap->child.buf.ptr[chap->child.buf.len] = '\0';
432     name = chap->child.buf.ptr;
433     name += strspn(name, " \t");
434     if ((key = strchr(name, '\n')) == NULL)
435       end = NULL;
436     else
437       end = strchr(++key, '\n');
438 
439     if (end == NULL) {
440       if (chap->child.buf.len == sizeof chap->child.buf.ptr - 1) {
441         log_Printf(LogWARN, "Chap: Read: Input buffer overflow\n");
442         chap_Cleanup(chap, SIGTERM);
443       }
444     } else {
445 #ifdef HAVE_DES
446       int lanman = chap->auth.physical->link.lcp.his_authtype == 0x80 &&
447                    ((chap->NTRespSent &&
448                      IsAccepted(chap->auth.physical->link.lcp.cfg.chap80lm)) ||
449                     !IsAccepted(chap->auth.physical->link.lcp.cfg.chap80nt));
450 #endif
451 
452       while (end >= name && strchr(" \t\r\n", *end))
453         *end-- = '\0';
454       end = key - 1;
455       while (end >= name && strchr(" \t\r\n", *end))
456         *end-- = '\0';
457       key += strspn(key, " \t");
458 
459       chap_Respond(chap, name, key, chap->auth.physical->link.lcp.his_authtype
460 #ifdef HAVE_DES
461                    , lanman
462 #endif
463                   );
464       chap_Cleanup(chap, 0);
465     }
466   }
467 }
468 
469 static int
470 chap_Write(struct fdescriptor *d, struct bundle *bundle, const fd_set *fdset)
471 {
472   /* We never want to write here ! */
473   log_Printf(LogALERT, "chap_Write: Internal error: Bad call !\n");
474   return 0;
475 }
476 
477 static void
478 chap_ChallengeInit(struct authinfo *authp)
479 {
480   struct chap *chap = auth2chap(authp);
481   int len, i;
482   char *cp;
483 
484   len = strlen(authp->physical->dl->bundle->cfg.auth.name);
485 
486   if (!*chap->challenge.local) {
487     randinit();
488     cp = chap->challenge.local;
489 
490 #ifndef NORADIUS
491     if (*authp->physical->dl->bundle->radius.cfg.file) {
492       /* For radius, our challenge is 16 readable NUL terminated bytes :*/
493       *cp++ = 16;
494       for (i = 0; i < 16; i++)
495         *cp++ = (random() % 10) + '0';
496     } else
497 #endif
498     {
499 #ifdef HAVE_DES
500       if (authp->physical->link.lcp.want_authtype == 0x80)
501         *cp++ = 8;	/* MS does 8 byte callenges :-/ */
502       else if (authp->physical->link.lcp.want_authtype == 0x81)
503         *cp++ = 16;	/* MS-CHAP-V2 does 16 bytes challenges */
504       else
505 #endif
506         *cp++ = random() % (CHAPCHALLENGELEN-16) + 16;
507       for (i = 0; i < *chap->challenge.local; i++)
508         *cp++ = random() & 0xff;
509     }
510     memcpy(cp, authp->physical->dl->bundle->cfg.auth.name, len);
511   }
512 }
513 
514 static void
515 chap_Challenge(struct authinfo *authp)
516 {
517   struct chap *chap = auth2chap(authp);
518   int len;
519 
520   log_Printf(LogDEBUG, "CHAP%02X: Challenge\n",
521              authp->physical->link.lcp.want_authtype);
522 
523   len = strlen(authp->physical->dl->bundle->cfg.auth.name);
524 
525   /* Generate new local challenge value */
526   if (!*chap->challenge.local)
527     chap_ChallengeInit(authp);
528 
529 #ifdef HAVE_DES
530   if (authp->physical->link.lcp.want_authtype == 0x81)
531     ChapOutput(authp->physical, CHAP_CHALLENGE, authp->id,
532              chap->challenge.local, 1 + *chap->challenge.local, NULL);
533   else
534 #endif
535     ChapOutput(authp->physical, CHAP_CHALLENGE, authp->id,
536              chap->challenge.local, 1 + *chap->challenge.local + len, NULL);
537 }
538 
539 static void
540 chap_Success(struct authinfo *authp)
541 {
542   const char *msg;
543   datalink_GotAuthname(authp->physical->dl, authp->in.name);
544 #ifdef HAVE_DES
545   if (authp->physical->link.lcp.want_authtype == 0x81) {
546     msg = auth2chap(authp)->authresponse;
547     MPPE_MasterKeyValid = 1;		/* XXX Global ! */
548   } else
549 #endif
550     msg = "Welcome!!";
551 
552   ChapOutput(authp->physical, CHAP_SUCCESS, authp->id, msg, strlen(msg) + 1,
553              NULL);
554 
555   authp->physical->link.lcp.auth_ineed = 0;
556   if (Enabled(authp->physical->dl->bundle, OPT_UTMP))
557     physical_Login(authp->physical, authp->in.name);
558 
559   if (authp->physical->link.lcp.auth_iwait == 0)
560     /*
561      * Either I didn't need to authenticate, or I've already been
562      * told that I got the answer right.
563      */
564     datalink_AuthOk(authp->physical->dl);
565 }
566 
567 static void
568 chap_Failure(struct authinfo *authp)
569 {
570 #ifdef HAVE_DES
571   char buf[1024];
572 #endif
573   const char *msg;
574 
575 #ifdef HAVE_DES
576   if (authp->physical->link.lcp.want_authtype == 0x81) {
577     char *ptr;
578     int i;
579 
580     ptr = buf;
581     ptr += sprintf(buf, "E=691 R=0 C=");
582     for (i=0; i<16; i++)
583       ptr += sprintf(ptr, "%02X", *(auth2chap(authp)->challenge.local+1+i));
584 
585     sprintf(ptr, " V=3 M=Invalid!");
586     msg = buf;
587   } else
588 #endif
589     msg = "Invalid!!";
590 
591   ChapOutput(authp->physical, CHAP_FAILURE, authp->id, msg, strlen(msg) + 1,
592              NULL);
593   datalink_AuthNotOk(authp->physical->dl);
594 }
595 
596 static int
597 chap_Cmp(u_char type, char *myans, int mylen, char *hisans, int hislen
598 #ifdef HAVE_DES
599          , int lm
600 #endif
601         )
602 {
603   if (mylen != hislen)
604     return 0;
605 #ifdef HAVE_DES
606   else if (type == 0x80) {
607     int off = lm ? 0 : 24;
608 
609     if (memcmp(myans + off, hisans + off, 24))
610       return 0;
611   }
612 #endif
613   else if (memcmp(myans, hisans, mylen))
614     return 0;
615 
616   return 1;
617 }
618 
619 #ifdef HAVE_DES
620 static int
621 chap_HaveAnotherGo(struct chap *chap)
622 {
623   if (++chap->peertries < 3) {
624     /* Give the peer another shot */
625     *chap->challenge.local = '\0';
626     chap_Challenge(&chap->auth);
627     return 1;
628   }
629 
630   return 0;
631 }
632 #endif
633 
634 void
635 chap_Init(struct chap *chap, struct physical *p)
636 {
637   chap->desc.type = CHAP_DESCRIPTOR;
638   chap->desc.UpdateSet = chap_UpdateSet;
639   chap->desc.IsSet = chap_IsSet;
640   chap->desc.Read = chap_Read;
641   chap->desc.Write = chap_Write;
642   chap->child.pid = 0;
643   chap->child.fd = -1;
644   auth_Init(&chap->auth, p, chap_Challenge, chap_Success, chap_Failure);
645   *chap->challenge.local = *chap->challenge.peer = '\0';
646 #ifdef HAVE_DES
647   chap->NTRespSent = 0;
648   chap->peertries = 0;
649 #endif
650 }
651 
652 void
653 chap_ReInit(struct chap *chap)
654 {
655   chap_Cleanup(chap, SIGTERM);
656 }
657 
658 struct mbuf *
659 chap_Input(struct bundle *bundle, struct link *l, struct mbuf *bp)
660 {
661   struct physical *p = link2physical(l);
662   struct chap *chap = &p->dl->chap;
663   char *name, *key, *ans;
664   int len, nlen;
665   u_char alen;
666 #ifdef HAVE_DES
667   int lanman;
668 #endif
669 
670   if (p == NULL) {
671     log_Printf(LogERROR, "chap_Input: Not a physical link - dropped\n");
672     m_freem(bp);
673     return NULL;
674   }
675 
676   if (bundle_Phase(bundle) != PHASE_NETWORK &&
677       bundle_Phase(bundle) != PHASE_AUTHENTICATE) {
678     log_Printf(LogPHASE, "Unexpected chap input - dropped !\n");
679     m_freem(bp);
680     return NULL;
681   }
682 
683   m_settype(bp, MB_CHAPIN);
684   if ((bp = auth_ReadHeader(&chap->auth, bp)) == NULL &&
685       ntohs(chap->auth.in.hdr.length) == 0)
686     log_Printf(LogWARN, "Chap Input: Truncated header !\n");
687   else if (chap->auth.in.hdr.code == 0 || chap->auth.in.hdr.code > MAXCHAPCODE)
688     log_Printf(LogPHASE, "Chap Input: %d: Bad CHAP code !\n",
689                chap->auth.in.hdr.code);
690   else {
691     len = m_length(bp);
692     ans = NULL;
693 
694     if (chap->auth.in.hdr.code != CHAP_CHALLENGE &&
695         chap->auth.id != chap->auth.in.hdr.id &&
696         Enabled(bundle, OPT_IDCHECK)) {
697       /* Wrong conversation dude ! */
698       log_Printf(LogPHASE, "Chap Input: %s dropped (got id %d, not %d)\n",
699                  chapcodes[chap->auth.in.hdr.code], chap->auth.in.hdr.id,
700                  chap->auth.id);
701       m_freem(bp);
702       return NULL;
703     }
704     chap->auth.id = chap->auth.in.hdr.id;	/* We respond with this id */
705 
706 #ifdef HAVE_DES
707     lanman = 0;
708 #endif
709     switch (chap->auth.in.hdr.code) {
710       case CHAP_CHALLENGE:
711         bp = mbuf_Read(bp, &alen, 1);
712         len -= alen + 1;
713         if (len < 0) {
714           log_Printf(LogERROR, "Chap Input: Truncated challenge !\n");
715           m_freem(bp);
716           return NULL;
717         }
718         *chap->challenge.peer = alen;
719         bp = mbuf_Read(bp, chap->challenge.peer + 1, alen);
720         bp = auth_ReadName(&chap->auth, bp, len);
721 #ifdef HAVE_DES
722         lanman = p->link.lcp.his_authtype == 0x80 &&
723                  ((chap->NTRespSent && IsAccepted(p->link.lcp.cfg.chap80lm)) ||
724                   !IsAccepted(p->link.lcp.cfg.chap80nt));
725 
726         /* Generate local challenge value */
727         chap_ChallengeInit(&chap->auth);
728 #endif
729         break;
730 
731       case CHAP_RESPONSE:
732         auth_StopTimer(&chap->auth);
733         bp = mbuf_Read(bp, &alen, 1);
734         len -= alen + 1;
735         if (len < 0) {
736           log_Printf(LogERROR, "Chap Input: Truncated response !\n");
737           m_freem(bp);
738           return NULL;
739         }
740         if ((ans = malloc(alen + 2)) == NULL) {
741           log_Printf(LogERROR, "Chap Input: Out of memory !\n");
742           m_freem(bp);
743           return NULL;
744         }
745         *ans = chap->auth.id;
746         bp = mbuf_Read(bp, ans + 1, alen);
747         ans[alen+1] = '\0';
748         bp = auth_ReadName(&chap->auth, bp, len);
749 #ifdef HAVE_DES
750         lanman = p->link.lcp.want_authtype == 0x80 &&
751                  alen == 49 && ans[alen] == 0;
752 #endif
753         break;
754 
755       case CHAP_SUCCESS:
756       case CHAP_FAILURE:
757         /* chap->auth.in.name is already set up at CHALLENGE time */
758         if ((ans = malloc(len + 1)) == NULL) {
759           log_Printf(LogERROR, "Chap Input: Out of memory !\n");
760           m_freem(bp);
761           return NULL;
762         }
763         bp = mbuf_Read(bp, ans, len);
764         ans[len] = '\0';
765         break;
766     }
767 
768     switch (chap->auth.in.hdr.code) {
769       case CHAP_CHALLENGE:
770       case CHAP_RESPONSE:
771         if (*chap->auth.in.name)
772           log_Printf(LogPHASE, "Chap Input: %s (%d bytes from %s%s)\n",
773                      chapcodes[chap->auth.in.hdr.code], alen,
774                      chap->auth.in.name,
775 #ifdef HAVE_DES
776                      lanman && chap->auth.in.hdr.code == CHAP_RESPONSE ?
777                      " - lanman" :
778 #endif
779                      "");
780         else
781           log_Printf(LogPHASE, "Chap Input: %s (%d bytes%s)\n",
782                      chapcodes[chap->auth.in.hdr.code], alen,
783 #ifdef HAVE_DES
784                      lanman && chap->auth.in.hdr.code == CHAP_RESPONSE ?
785                      " - lanman" :
786 #endif
787                      "");
788         break;
789 
790       case CHAP_SUCCESS:
791       case CHAP_FAILURE:
792         if (*ans)
793           log_Printf(LogPHASE, "Chap Input: %s (%s)\n",
794                      chapcodes[chap->auth.in.hdr.code], ans);
795         else
796           log_Printf(LogPHASE, "Chap Input: %s\n",
797                      chapcodes[chap->auth.in.hdr.code]);
798         break;
799     }
800 
801     switch (chap->auth.in.hdr.code) {
802       case CHAP_CHALLENGE:
803         if (*bundle->cfg.auth.key == '!' && bundle->cfg.auth.key[1] != '!')
804           chap_StartChild(chap, bundle->cfg.auth.key + 1,
805                           bundle->cfg.auth.name);
806         else
807           chap_Respond(chap, bundle->cfg.auth.name, bundle->cfg.auth.key +
808                        (*bundle->cfg.auth.key == '!' ? 1 : 0),
809                        p->link.lcp.his_authtype
810 #ifdef HAVE_DES
811                        , lanman
812 #endif
813                       );
814         break;
815 
816       case CHAP_RESPONSE:
817         name = chap->auth.in.name;
818         nlen = strlen(name);
819 #ifndef NORADIUS
820         if (*bundle->radius.cfg.file)
821           radius_Authenticate(&bundle->radius, &chap->auth,
822                               chap->auth.in.name, ans, alen + 1,
823                               chap->challenge.local + 1,
824                               *chap->challenge.local);
825         else
826 #endif
827         {
828           key = auth_GetSecret(bundle, name, nlen, p);
829           if (key) {
830             char *myans;
831 #ifdef HAVE_DES
832             if (p->link.lcp.want_authtype == 0x80 &&
833                 lanman && !IsEnabled(p->link.lcp.cfg.chap80lm)) {
834               log_Printf(LogPHASE, "Auth failure: LANMan not enabled\n");
835               if (chap_HaveAnotherGo(chap))
836                 break;
837               key = NULL;
838             } else if (p->link.lcp.want_authtype == 0x80 &&
839                 !lanman && !IsEnabled(p->link.lcp.cfg.chap80nt)) {
840               log_Printf(LogPHASE, "Auth failure: mschap not enabled\n");
841               if (chap_HaveAnotherGo(chap))
842                 break;
843               key = NULL;
844             } else if (p->link.lcp.want_authtype == 0x81 &&
845                 !IsEnabled(p->link.lcp.cfg.chap81)) {
846               log_Printf(LogPHASE, "Auth failure: CHAP81 not enabled\n");
847               key = NULL;
848             } else
849 #endif
850             {
851 #ifdef HAVE_DES
852               /* Get peer's challenge */
853               if (p->link.lcp.want_authtype == 0x81) {
854                 chap->challenge.peer[0] = CHAP81_CHALLENGE_LEN;
855                 memcpy(chap->challenge.peer + 1, ans + 1, CHAP81_CHALLENGE_LEN);
856               }
857 #endif
858 
859               myans = chap_BuildAnswer(name, key, chap->auth.id,
860                                        chap->challenge.local,
861                                        p->link.lcp.want_authtype
862 #ifdef HAVE_DES
863                                        , chap->challenge.peer,
864                                        chap->authresponse, lanman);
865               MPPE_IsServer = 1;		/* XXX Global ! */
866 #else
867                                       );
868 #endif
869               if (myans == NULL)
870                 key = NULL;
871               else {
872                 if (!chap_Cmp(p->link.lcp.want_authtype, myans + 1, *myans,
873                               ans + 1, alen
874 #ifdef HAVE_DES
875                               , lanman
876 #endif
877                              ))
878                   key = NULL;
879                 free(myans);
880               }
881             }
882           }
883 
884           if (key)
885             chap_Success(&chap->auth);
886           else
887             chap_Failure(&chap->auth);
888         }
889 
890         break;
891 
892       case CHAP_SUCCESS:
893         if (p->link.lcp.auth_iwait == PROTO_CHAP) {
894           p->link.lcp.auth_iwait = 0;
895           if (p->link.lcp.auth_ineed == 0) {
896 #ifdef HAVE_DES
897             if (p->link.lcp.his_authtype == 0x81) {
898               if (strncmp(ans, chap->authresponse, 42)) {
899                 datalink_AuthNotOk(p->dl);
900 	        log_Printf(LogDEBUG, "CHAP81: AuthenticatorResponse: (%s)"
901                            " != ans: (%s)\n", chap->authresponse, ans);
902 
903               } else {
904                 /* Successful login */
905                 MPPE_MasterKeyValid = 1;		/* XXX Global ! */
906                 datalink_AuthOk(p->dl);
907               }
908             } else
909 #endif
910             /*
911              * We've succeeded in our ``login''
912              * If we're not expecting  the peer to authenticate (or he already
913              * has), proceed to network phase.
914              */
915             datalink_AuthOk(p->dl);
916           }
917         }
918         break;
919 
920       case CHAP_FAILURE:
921         datalink_AuthNotOk(p->dl);
922         break;
923     }
924     free(ans);
925   }
926 
927   m_freem(bp);
928   return NULL;
929 }
930