chap.c revision 36287 
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 1.31 1998/05/21 21:44:25 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 <md4.h>
31#include <md5.h>
32#include <stdlib.h>
33#include <string.h>
34#include <termios.h>
35
36#include "mbuf.h"
37#include "log.h"
38#include "defs.h"
39#include "timer.h"
40#include "fsm.h"
41#include "lcpproto.h"
42#include "lcp.h"
43#include "lqr.h"
44#include "hdlc.h"
45#include "auth.h"
46#include "chap.h"
47#include "async.h"
48#include "throughput.h"
49#include "descriptor.h"
50#include "iplist.h"
51#include "slcompress.h"
52#include "ipcp.h"
53#include "filter.h"
54#include "ccp.h"
55#include "link.h"
56#include "physical.h"
57#include "mp.h"
58#include "bundle.h"
59#include "chat.h"
60#include "datalink.h"
61#include "chap_ms.h"
62
63static const char *chapcodes[] = {
64  "???", "CHALLENGE", "RESPONSE", "SUCCESS", "FAILURE"
65};
66
67static void
68ChapOutput(struct physical *physical, u_int code, u_int id,
69	   const u_char * ptr, int count)
70{
71  int plen;
72  struct fsmheader lh;
73  struct mbuf *bp;
74
75  plen = sizeof(struct fsmheader) + count;
76  lh.code = code;
77  lh.id = id;
78  lh.length = htons(plen);
79  bp = mbuf_Alloc(plen, MB_FSM);
80  memcpy(MBUF_CTOP(bp), &lh, sizeof(struct fsmheader));
81  if (count)
82    memcpy(MBUF_CTOP(bp) + sizeof(struct fsmheader), ptr, count);
83  log_DumpBp(LogDEBUG, "ChapOutput", bp);
84  log_Printf(LogLCP, "ChapOutput: %s\n", chapcodes[code]);
85  hdlc_Output(&physical->link, PRI_LINK, PROTO_CHAP, bp);
86}
87
88void
89chap_SendChallenge(struct authinfo *auth, int chapid, struct physical *physical)
90{
91  struct chap *chap = auth2chap(auth);
92  int len, i;
93  char *cp;
94
95  randinit();
96  cp = chap->challenge_data;
97  *cp++ = chap->challenge_len = random() % 32 + 16;
98  for (i = 0; i < chap->challenge_len; i++)
99    *cp++ = random() & 0xff;
100  len = strlen(physical->dl->bundle->cfg.auth.name);
101  memcpy(cp, physical->dl->bundle->cfg.auth.name, len);
102  cp += len;
103  ChapOutput(physical, CHAP_CHALLENGE, chapid, chap->challenge_data,
104	     cp - chap->challenge_data);
105}
106
107static void
108RecvChapTalk(struct bundle *bundle, struct fsmheader *chp, struct mbuf *bp,
109             struct physical *physical)
110{
111  int valsize, len;
112  int arglen, keylen, namelen;
113  char *cp, *argp, *ap, *name, *digest;
114  char *keyp;
115  MD5_CTX MD5context;		/* context for MD5 */
116  char answer[100];
117  char cdigest[16];
118#ifdef HAVE_DES
119  int ix;
120  MD4_CTX MD4context;		/* context for MD4 */
121#endif
122
123  len = ntohs(chp->length);
124  log_Printf(LogDEBUG, "RecvChapTalk: length: %d\n", len);
125  arglen = len - sizeof(struct fsmheader);
126  cp = (char *) MBUF_CTOP(bp);
127  valsize = *cp++ & 255;
128  name = cp + valsize;
129  namelen = arglen - valsize - 1;
130  name[namelen] = 0;
131  log_Printf(LogLCP, " Valsize = %d, Name = \"%s\"\n", valsize, name);
132
133  switch (chp->code) {
134  case CHAP_CHALLENGE:
135    keyp = bundle->cfg.auth.key;
136    keylen = strlen(bundle->cfg.auth.key);
137    name = bundle->cfg.auth.name;
138    namelen = strlen(bundle->cfg.auth.name);
139
140#ifdef HAVE_DES
141    if (physical->dl->chap.using_MSChap)
142      argp = malloc(1 + namelen + MS_CHAP_RESPONSE_LEN);
143    else
144#endif
145      argp = malloc(1 + valsize + namelen + 16);
146
147    if (argp == NULL) {
148      ChapOutput(physical, CHAP_FAILURE, chp->id, "Out of memory!", 14);
149      return;
150    }
151#ifdef HAVE_DES
152    if (physical->dl->chap.using_MSChap) {
153      digest = argp;     /* this is the response */
154      *digest++ = MS_CHAP_RESPONSE_LEN;   /* 49 */
155      memset(digest, '\0', 24);
156      digest += 24;
157
158      ap = answer;       /* this is the challenge */
159      memcpy(ap, keyp, keylen);
160      ap += 2 * keylen;
161      memcpy(ap, cp, valsize);
162      log_DumpBuff(LogDEBUG, "recv", ap, valsize);
163      ap += valsize;
164      for (ix = keylen; ix > 0 ; ix--) {
165          answer[2*ix-2] = answer[ix-1];
166          answer[2*ix-1] = 0;
167      }
168      MD4Init(&MD4context);
169      MD4Update(&MD4context, answer, 2 * keylen);
170      MD4Final(digest, &MD4context);
171      memcpy(digest + 25, name, namelen);
172      ap += 2 * keylen;
173      chap_MS(digest, answer + 2 * keylen, valsize);
174      log_DumpBuff(LogDEBUG, "answer", digest, 24);
175      ChapOutput(physical, CHAP_RESPONSE, chp->id, argp,
176		 namelen + MS_CHAP_RESPONSE_LEN + 1);
177    } else {
178#endif
179      digest = argp;
180      *digest++ = 16;		/* value size */
181      ap = answer;
182      *ap++ = chp->id;
183      memcpy(ap, keyp, keylen);
184      ap += keylen;
185      memcpy(ap, cp, valsize);
186      log_DumpBuff(LogDEBUG, "recv", ap, valsize);
187      ap += valsize;
188      MD5Init(&MD5context);
189      MD5Update(&MD5context, answer, ap - answer);
190      MD5Final(digest, &MD5context);
191      log_DumpBuff(LogDEBUG, "answer", digest, 16);
192      memcpy(digest + 16, name, namelen);
193      ap += namelen;
194      /* Send answer to the peer */
195      ChapOutput(physical, CHAP_RESPONSE, chp->id, argp, namelen + 17);
196#ifdef HAVE_DES
197    }
198#endif
199    free(argp);
200    break;
201  case CHAP_RESPONSE:
202    /*
203     * Get a secret key corresponds to the peer
204     */
205    keyp = auth_GetSecret(bundle, name, namelen, physical);
206    if (keyp) {
207      /*
208       * Compute correct digest value
209       */
210      keylen = strlen(keyp);
211      ap = answer;
212      *ap++ = chp->id;
213      memcpy(ap, keyp, keylen);
214      ap += keylen;
215      MD5Init(&MD5context);
216      MD5Update(&MD5context, answer, ap - answer);
217      MD5Update(&MD5context, physical->dl->chap.challenge_data + 1,
218                physical->dl->chap.challenge_len);
219      MD5Final(cdigest, &MD5context);
220      log_DumpBuff(LogDEBUG, "got", cp, 16);
221      log_DumpBuff(LogDEBUG, "expect", cdigest, 16);
222
223      /*
224       * Compare with the response
225       */
226      if (memcmp(cp, cdigest, 16) == 0) {
227        datalink_GotAuthname(physical->dl, name, namelen);
228	ChapOutput(physical, CHAP_SUCCESS, chp->id, "Welcome!!", 10);
229        if (Enabled(bundle, OPT_UTMP))
230          physical_Login(physical, name);
231
232        if (physical->link.lcp.auth_iwait == 0)
233          /*
234           * Either I didn't need to authenticate, or I've already been
235           * told that I got the answer right.
236           */
237          datalink_AuthOk(physical->dl);
238
239	break;
240      }
241    }
242
243    /*
244     * Peer is not registerd, or response digest is wrong.
245     */
246    ChapOutput(physical, CHAP_FAILURE, chp->id, "Invalid!!", 9);
247    datalink_AuthNotOk(physical->dl);
248    break;
249  }
250}
251
252static void
253RecvChapResult(struct bundle *bundle, struct fsmheader *chp, struct mbuf *bp,
254	       struct physical *physical)
255{
256  int len;
257
258  len = ntohs(chp->length);
259  log_Printf(LogDEBUG, "RecvChapResult: length: %d\n", len);
260  if (chp->code == CHAP_SUCCESS) {
261    if (physical->link.lcp.auth_iwait == PROTO_CHAP) {
262      physical->link.lcp.auth_iwait = 0;
263      if (physical->link.lcp.auth_ineed == 0)
264        /*
265         * We've succeeded in our ``login''
266         * If we're not expecting  the peer to authenticate (or he already
267         * has), proceed to network phase.
268         */
269        datalink_AuthOk(physical->dl);
270    }
271  } else {
272    /* CHAP failed - it's not going to get any better */
273    log_Printf(LogPHASE, "Received CHAP_FAILURE\n");
274    datalink_AuthNotOk(physical->dl);
275  }
276}
277
278void
279chap_Input(struct bundle *bundle, struct mbuf *bp, struct physical *physical)
280{
281  int len = mbuf_Length(bp);
282  struct fsmheader *chp;
283
284  if (len >= sizeof(struct fsmheader)) {
285    chp = (struct fsmheader *) MBUF_CTOP(bp);
286    if (len >= ntohs(chp->length)) {
287      if (chp->code < 1 || chp->code > 4)
288	chp->code = 0;
289      log_Printf(LogLCP, "chap_Input: %s\n", chapcodes[chp->code]);
290
291      bp->offset += sizeof(struct fsmheader);
292      bp->cnt -= sizeof(struct fsmheader);
293
294      switch (chp->code) {
295      case CHAP_RESPONSE:
296	auth_StopTimer(&physical->dl->chap.auth);
297	/* Fall into.. */
298      case CHAP_CHALLENGE:
299	RecvChapTalk(bundle, chp, bp, physical);
300	break;
301      case CHAP_SUCCESS:
302      case CHAP_FAILURE:
303	RecvChapResult(bundle, chp, bp, physical);
304	break;
305      }
306    }
307  }
308  mbuf_Free(bp);
309}
310