chap.c revision 36285 
1/*
2 *			PPP CHAP Module
3 *
4 *	    Written by Toshiharu OHNO (tony-o@iij.ad.jp)
5 *
6 *   Copyright (C) 1993, Internet Initiative Japan, Inc. All rights reserverd.
7 *
8 * Redistribution and use in source and binary forms are permitted
9 * provided that the above copyright notice and this paragraph are
10 * duplicated in all such forms and that any documentation,
11 * advertising materials, and other materials related to such
12 * distribution and use acknowledge that the software was developed
13 * by the Internet Initiative Japan, Inc.  The name of the
14 * IIJ may not be used to endorse or promote products derived
15 * from this software without specific prior written permission.
16 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
18 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
19 *
20 * $Id: chap.c,v 1.28.2.27 1998/05/01 19:24:03 brian Exp $
21 *
22 *	TODO:
23 */
24#include <sys/types.h>
25#include <netinet/in.h>
26#include <netinet/in_systm.h>
27#include <netinet/ip.h>
28#include <sys/un.h>
29
30#include <md5.h>
31#include <stdlib.h>
32#include <termios.h>
33
34#include "mbuf.h"
35#include "log.h"
36#include "defs.h"
37#include "timer.h"
38#include "fsm.h"
39#include "lcpproto.h"
40#include "lcp.h"
41#include "lqr.h"
42#include "hdlc.h"
43#include "auth.h"
44#include "chap.h"
45#include "async.h"
46#include "throughput.h"
47#include "descriptor.h"
48#include "iplist.h"
49#include "slcompress.h"
50#include "ipcp.h"
51#include "filter.h"
52#include "ccp.h"
53#include "link.h"
54#include "physical.h"
55#include "mp.h"
56#include "bundle.h"
57#include "chat.h"
58#include "datalink.h"
59
60static const char *chapcodes[] = {
61  "???", "CHALLENGE", "RESPONSE", "SUCCESS", "FAILURE"
62};
63
64static void
65ChapOutput(struct physical *physical, u_int code, u_int id,
66	   const u_char * ptr, int count)
67{
68  int plen;
69  struct fsmheader lh;
70  struct mbuf *bp;
71
72  plen = sizeof(struct fsmheader) + count;
73  lh.code = code;
74  lh.id = id;
75  lh.length = htons(plen);
76  bp = mbuf_Alloc(plen, MB_FSM);
77  memcpy(MBUF_CTOP(bp), &lh, sizeof(struct fsmheader));
78  if (count)
79    memcpy(MBUF_CTOP(bp) + sizeof(struct fsmheader), ptr, count);
80  log_DumpBp(LogDEBUG, "ChapOutput", bp);
81  log_Printf(LogLCP, "ChapOutput: %s\n", chapcodes[code]);
82  hdlc_Output(&physical->link, PRI_LINK, PROTO_CHAP, bp);
83}
84
85void
86chap_SendChallenge(struct authinfo *auth, int chapid, struct physical *physical)
87{
88  struct chap *chap = auth2chap(auth);
89  int len, i;
90  char *cp;
91
92  randinit();
93  cp = chap->challenge_data;
94  *cp++ = chap->challenge_len = random() % 32 + 16;
95  for (i = 0; i < chap->challenge_len; i++)
96    *cp++ = random() & 0xff;
97  len = strlen(physical->dl->bundle->cfg.auth.name);
98  memcpy(cp, physical->dl->bundle->cfg.auth.name, len);
99  cp += len;
100  ChapOutput(physical, CHAP_CHALLENGE, chapid, chap->challenge_data,
101	     cp - chap->challenge_data);
102}
103
104static void
105RecvChapTalk(struct bundle *bundle, struct fsmheader *chp, struct mbuf *bp,
106             struct physical *physical)
107{
108  int valsize, len;
109  int arglen, keylen, namelen;
110  char *cp, *argp, *ap, *name, *digest;
111  char *keyp;
112  MD5_CTX MD5context;		/* context for MD5 */
113  char answer[100];
114  char cdigest[16];
115#ifdef HAVE_DES
116  int ix;
117  MD4_CTX MD4context;		/* context for MD4 */
118#endif
119
120  len = ntohs(chp->length);
121  log_Printf(LogDEBUG, "RecvChapTalk: length: %d\n", len);
122  arglen = len - sizeof(struct fsmheader);
123  cp = (char *) MBUF_CTOP(bp);
124  valsize = *cp++ & 255;
125  name = cp + valsize;
126  namelen = arglen - valsize - 1;
127  name[namelen] = 0;
128  log_Printf(LogLCP, " Valsize = %d, Name = \"%s\"\n", valsize, name);
129
130  switch (chp->code) {
131  case CHAP_CHALLENGE:
132    keyp = bundle->cfg.auth.key;
133    keylen = strlen(bundle->cfg.auth.key);
134    name = bundle->cfg.auth.name;
135    namelen = strlen(bundle->cfg.auth.name);
136
137#ifdef HAVE_DES
138    if (physical->dl->chap.using_MSChap)
139      argp = malloc(1 + namelen + MS_CHAP_RESPONSE_LEN);
140    else
141#endif
142      argp = malloc(1 + valsize + namelen + 16);
143
144    if (argp == NULL) {
145      ChapOutput(physical, CHAP_FAILURE, chp->id, "Out of memory!", 14);
146      return;
147    }
148#ifdef HAVE_DES
149    if (physical->dl->chap.using_MSChap) {
150      digest = argp;     /* this is the response */
151      *digest++ = MS_CHAP_RESPONSE_LEN;   /* 49 */
152      memset(digest, '\0', 24);
153      digest += 24;
154
155      ap = answer;       /* this is the challenge */
156      memcpy(ap, keyp, keylen);
157      ap += 2 * keylen;
158      memcpy(ap, cp, valsize);
159      log_DumpBuff(LogDEBUG, "recv", ap, valsize);
160      ap += valsize;
161      for (ix = keylen; ix > 0 ; ix--) {
162          answer[2*ix-2] = answer[ix-1];
163          answer[2*ix-1] = 0;
164      }
165      MD4Init(&MD4context);
166      MD4Update(&MD4context, answer, 2 * keylen);
167      MD4Final(digest, &MD4context);
168      memcpy(digest + 25, name, namelen);
169      ap += 2 * keylen;
170      chap_MS(digest, answer + 2 * keylen, valsize);
171      log_DumpBuff(LogDEBUG, "answer", digest, 24);
172      ChapOutput(physical, CHAP_RESPONSE, chp->id, argp,
173		 namelen + MS_CHAP_RESPONSE_LEN + 1);
174    } else {
175#endif
176      digest = argp;
177      *digest++ = 16;		/* value size */
178      ap = answer;
179      *ap++ = chp->id;
180      memcpy(ap, keyp, keylen);
181      ap += keylen;
182      memcpy(ap, cp, valsize);
183      log_DumpBuff(LogDEBUG, "recv", ap, valsize);
184      ap += valsize;
185      MD5Init(&MD5context);
186      MD5Update(&MD5context, answer, ap - answer);
187      MD5Final(digest, &MD5context);
188      log_DumpBuff(LogDEBUG, "answer", digest, 16);
189      memcpy(digest + 16, name, namelen);
190      ap += namelen;
191      /* Send answer to the peer */
192      ChapOutput(physical, CHAP_RESPONSE, chp->id, argp, namelen + 17);
193#ifdef HAVE_DES
194    }
195#endif
196    free(argp);
197    break;
198  case CHAP_RESPONSE:
199    /*
200     * Get a secret key corresponds to the peer
201     */
202    keyp = auth_GetSecret(bundle, name, namelen, physical);
203    if (keyp) {
204      /*
205       * Compute correct digest value
206       */
207      keylen = strlen(keyp);
208      ap = answer;
209      *ap++ = chp->id;
210      memcpy(ap, keyp, keylen);
211      ap += keylen;
212      MD5Init(&MD5context);
213      MD5Update(&MD5context, answer, ap - answer);
214      MD5Update(&MD5context, physical->dl->chap.challenge_data + 1,
215                physical->dl->chap.challenge_len);
216      MD5Final(cdigest, &MD5context);
217      log_DumpBuff(LogDEBUG, "got", cp, 16);
218      log_DumpBuff(LogDEBUG, "expect", cdigest, 16);
219
220      /*
221       * Compare with the response
222       */
223      if (memcmp(cp, cdigest, 16) == 0) {
224        datalink_GotAuthname(physical->dl, name, namelen);
225	ChapOutput(physical, CHAP_SUCCESS, chp->id, "Welcome!!", 10);
226        if (Enabled(bundle, OPT_UTMP))
227          physical_Login(physical, name);
228
229        if (physical->link.lcp.auth_iwait == 0)
230          /*
231           * Either I didn't need to authenticate, or I've already been
232           * told that I got the answer right.
233           */
234          datalink_AuthOk(physical->dl);
235
236	break;
237      }
238    }
239
240    /*
241     * Peer is not registerd, or response digest is wrong.
242     */
243    ChapOutput(physical, CHAP_FAILURE, chp->id, "Invalid!!", 9);
244    datalink_AuthNotOk(physical->dl);
245    break;
246  }
247}
248
249static void
250RecvChapResult(struct bundle *bundle, struct fsmheader *chp, struct mbuf *bp,
251	       struct physical *physical)
252{
253  int len;
254
255  len = ntohs(chp->length);
256  log_Printf(LogDEBUG, "RecvChapResult: length: %d\n", len);
257  if (chp->code == CHAP_SUCCESS) {
258    if (physical->link.lcp.auth_iwait == PROTO_CHAP) {
259      physical->link.lcp.auth_iwait = 0;
260      if (physical->link.lcp.auth_ineed == 0)
261        /*
262         * We've succeeded in our ``login''
263         * If we're not expecting  the peer to authenticate (or he already
264         * has), proceed to network phase.
265         */
266        datalink_AuthOk(physical->dl);
267    }
268  } else {
269    /* CHAP failed - it's not going to get any better */
270    log_Printf(LogPHASE, "Received CHAP_FAILURE\n");
271    datalink_AuthNotOk(physical->dl);
272  }
273}
274
275void
276chap_Input(struct bundle *bundle, struct mbuf *bp, struct physical *physical)
277{
278  int len = mbuf_Length(bp);
279  struct fsmheader *chp;
280
281  if (len >= sizeof(struct fsmheader)) {
282    chp = (struct fsmheader *) MBUF_CTOP(bp);
283    if (len >= ntohs(chp->length)) {
284      if (chp->code < 1 || chp->code > 4)
285	chp->code = 0;
286      log_Printf(LogLCP, "chap_Input: %s\n", chapcodes[chp->code]);
287
288      bp->offset += sizeof(struct fsmheader);
289      bp->cnt -= sizeof(struct fsmheader);
290
291      switch (chp->code) {
292      case CHAP_RESPONSE:
293	auth_StopTimer(&physical->dl->chap.auth);
294	/* Fall into.. */
295      case CHAP_CHALLENGE:
296	RecvChapTalk(bundle, chp, bp, physical);
297	break;
298      case CHAP_SUCCESS:
299      case CHAP_FAILURE:
300	RecvChapResult(bundle, chp, bp, physical);
301	break;
302      }
303    }
304  }
305  mbuf_Free(bp);
306}
307