chap.c revision 37210 
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 1.33 1998/06/27 14:18:01 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#ifdef HAVE_DES
31#include <md4.h>
32#endif
33#include <md5.h>
34#include <stdlib.h>
35#include <string.h>
36#include <termios.h>
37
38#include "mbuf.h"
39#include "log.h"
40#include "defs.h"
41#include "timer.h"
42#include "fsm.h"
43#include "lcpproto.h"
44#include "lcp.h"
45#include "lqr.h"
46#include "hdlc.h"
47#include "auth.h"
48#include "chap.h"
49#include "async.h"
50#include "throughput.h"
51#include "descriptor.h"
52#include "iplist.h"
53#include "slcompress.h"
54#include "ipcp.h"
55#include "filter.h"
56#include "ccp.h"
57#include "link.h"
58#include "physical.h"
59#include "mp.h"
60#include "bundle.h"
61#include "chat.h"
62#include "datalink.h"
63#ifdef HAVE_DES
64#include "chap_ms.h"
65#endif
66
67static const char *chapcodes[] = {
68  "???", "CHALLENGE", "RESPONSE", "SUCCESS", "FAILURE"
69};
70
71static void
72ChapOutput(struct physical *physical, u_int code, u_int id,
73	   const u_char * ptr, int count)
74{
75  int plen;
76  struct fsmheader lh;
77  struct mbuf *bp;
78
79  plen = sizeof(struct fsmheader) + count;
80  lh.code = code;
81  lh.id = id;
82  lh.length = htons(plen);
83  bp = mbuf_Alloc(plen, MB_FSM);
84  memcpy(MBUF_CTOP(bp), &lh, sizeof(struct fsmheader));
85  if (count)
86    memcpy(MBUF_CTOP(bp) + sizeof(struct fsmheader), ptr, count);
87  log_DumpBp(LogDEBUG, "ChapOutput", bp);
88  log_Printf(LogLCP, "ChapOutput: %s\n", chapcodes[code]);
89  hdlc_Output(&physical->link, PRI_LINK, PROTO_CHAP, bp);
90}
91
92void
93chap_SendChallenge(struct authinfo *auth, int chapid, struct physical *physical)
94{
95  struct chap *chap = auth2chap(auth);
96  int len, i;
97  char *cp;
98
99  randinit();
100  cp = chap->challenge_data;
101  *cp++ = chap->challenge_len = random() % 32 + 16;
102  for (i = 0; i < chap->challenge_len; i++)
103    *cp++ = random() & 0xff;
104  len = strlen(physical->dl->bundle->cfg.auth.name);
105  memcpy(cp, physical->dl->bundle->cfg.auth.name, len);
106  cp += len;
107  ChapOutput(physical, CHAP_CHALLENGE, chapid, chap->challenge_data,
108	     cp - chap->challenge_data);
109}
110
111static void
112RecvChapTalk(struct bundle *bundle, struct fsmheader *chp, struct mbuf *bp,
113             struct physical *physical)
114{
115  int valsize, len;
116  int arglen, keylen, namelen;
117  char *cp, *argp, *ap, *name, *digest;
118  char *keyp;
119  MD5_CTX MD5context;		/* context for MD5 */
120  char answer[100];
121  char cdigest[16];
122#ifdef HAVE_DES
123  int ix;
124  MD4_CTX MD4context;		/* context for MD4 */
125#endif
126
127  len = ntohs(chp->length);
128  log_Printf(LogDEBUG, "RecvChapTalk: length: %d\n", len);
129  arglen = len - sizeof(struct fsmheader);
130  cp = (char *) MBUF_CTOP(bp);
131  valsize = *cp++ & 255;
132  name = cp + valsize;
133  namelen = arglen - valsize - 1;
134  name[namelen] = 0;
135  log_Printf(LogLCP, " Valsize = %d, Name = \"%s\"\n", valsize, name);
136
137  switch (chp->code) {
138  case CHAP_CHALLENGE:
139    keyp = bundle->cfg.auth.key;
140    keylen = strlen(bundle->cfg.auth.key);
141    name = bundle->cfg.auth.name;
142    namelen = strlen(bundle->cfg.auth.name);
143
144#ifdef HAVE_DES
145    if (physical->dl->chap.using_MSChap)
146      argp = malloc(1 + namelen + MS_CHAP_RESPONSE_LEN);
147    else
148#endif
149      argp = malloc(1 + valsize + namelen + 16);
150
151    if (argp == NULL) {
152      ChapOutput(physical, CHAP_FAILURE, chp->id, "Out of memory!", 14);
153      return;
154    }
155#ifdef HAVE_DES
156    if (physical->dl->chap.using_MSChap) {
157      digest = argp;     /* this is the response */
158      *digest++ = MS_CHAP_RESPONSE_LEN;   /* 49 */
159      memset(digest, '\0', 24);
160      digest += 24;
161
162      ap = answer;       /* this is the challenge */
163      memcpy(ap, keyp, keylen);
164      ap += 2 * keylen;
165      memcpy(ap, cp, valsize);
166      log_DumpBuff(LogDEBUG, "recv", ap, valsize);
167      ap += valsize;
168      for (ix = keylen; ix > 0 ; ix--) {
169          answer[2*ix-2] = answer[ix-1];
170          answer[2*ix-1] = 0;
171      }
172      MD4Init(&MD4context);
173      MD4Update(&MD4context, answer, 2 * keylen);
174      MD4Final(digest, &MD4context);
175      memcpy(digest + 25, name, namelen);
176      ap += 2 * keylen;
177      chap_MS(digest, answer + 2 * keylen, valsize);
178      log_DumpBuff(LogDEBUG, "answer", digest, 24);
179      ChapOutput(physical, CHAP_RESPONSE, chp->id, argp,
180		 namelen + MS_CHAP_RESPONSE_LEN + 1);
181    } else {
182#endif
183      digest = argp;
184      *digest++ = 16;		/* value size */
185      ap = answer;
186      *ap++ = chp->id;
187      memcpy(ap, keyp, keylen);
188      ap += keylen;
189      memcpy(ap, cp, valsize);
190      log_DumpBuff(LogDEBUG, "recv", ap, valsize);
191      ap += valsize;
192      MD5Init(&MD5context);
193      MD5Update(&MD5context, answer, ap - answer);
194      MD5Final(digest, &MD5context);
195      log_DumpBuff(LogDEBUG, "answer", digest, 16);
196      memcpy(digest + 16, name, namelen);
197      ap += namelen;
198      /* Send answer to the peer */
199      ChapOutput(physical, CHAP_RESPONSE, chp->id, argp, namelen + 17);
200#ifdef HAVE_DES
201    }
202#endif
203    free(argp);
204    break;
205  case CHAP_RESPONSE:
206    /*
207     * Get a secret key corresponds to the peer
208     */
209    keyp = auth_GetSecret(bundle, name, namelen, physical);
210    if (keyp) {
211      /*
212       * Compute correct digest value
213       */
214      keylen = strlen(keyp);
215      ap = answer;
216      *ap++ = chp->id;
217      memcpy(ap, keyp, keylen);
218      ap += keylen;
219      MD5Init(&MD5context);
220      MD5Update(&MD5context, answer, ap - answer);
221      MD5Update(&MD5context, physical->dl->chap.challenge_data + 1,
222                physical->dl->chap.challenge_len);
223      MD5Final(cdigest, &MD5context);
224      log_DumpBuff(LogDEBUG, "got", cp, 16);
225      log_DumpBuff(LogDEBUG, "expect", cdigest, 16);
226
227      /*
228       * Compare with the response
229       */
230      if (memcmp(cp, cdigest, 16) == 0) {
231        datalink_GotAuthname(physical->dl, name, namelen);
232	ChapOutput(physical, CHAP_SUCCESS, chp->id, "Welcome!!", 10);
233        if (Enabled(bundle, OPT_UTMP))
234          physical_Login(physical, name);
235
236        if (physical->link.lcp.auth_iwait == 0)
237          /*
238           * Either I didn't need to authenticate, or I've already been
239           * told that I got the answer right.
240           */
241          datalink_AuthOk(physical->dl);
242
243	break;
244      }
245    }
246
247    /*
248     * Peer is not registerd, or response digest is wrong.
249     */
250    ChapOutput(physical, CHAP_FAILURE, chp->id, "Invalid!!", 9);
251    datalink_AuthNotOk(physical->dl);
252    break;
253  }
254}
255
256static void
257RecvChapResult(struct bundle *bundle, struct fsmheader *chp, struct mbuf *bp,
258	       struct physical *physical)
259{
260  int len;
261
262  len = ntohs(chp->length);
263  log_Printf(LogDEBUG, "RecvChapResult: length: %d\n", len);
264  if (chp->code == CHAP_SUCCESS) {
265    if (physical->link.lcp.auth_iwait == PROTO_CHAP) {
266      physical->link.lcp.auth_iwait = 0;
267      if (physical->link.lcp.auth_ineed == 0)
268        /*
269         * We've succeeded in our ``login''
270         * If we're not expecting  the peer to authenticate (or he already
271         * has), proceed to network phase.
272         */
273        datalink_AuthOk(physical->dl);
274    }
275  } else {
276    /* CHAP failed - it's not going to get any better */
277    log_Printf(LogPHASE, "Received CHAP_FAILURE\n");
278    datalink_AuthNotOk(physical->dl);
279  }
280}
281
282void
283chap_Input(struct bundle *bundle, struct mbuf *bp, struct physical *physical)
284{
285  int len = mbuf_Length(bp);
286  struct fsmheader *chp;
287
288  if (len >= sizeof(struct fsmheader)) {
289    chp = (struct fsmheader *) MBUF_CTOP(bp);
290    if (len >= ntohs(chp->length)) {
291      if (chp->code < 1 || chp->code > 4)
292	chp->code = 0;
293      log_Printf(LogLCP, "chap_Input: %s\n", chapcodes[chp->code]);
294
295      bp->offset += sizeof(struct fsmheader);
296      bp->cnt -= sizeof(struct fsmheader);
297
298      switch (chp->code) {
299      case CHAP_RESPONSE:
300	auth_StopTimer(&physical->dl->chap.auth);
301	/* Fall into.. */
302      case CHAP_CHALLENGE:
303	RecvChapTalk(bundle, chp, bp, physical);
304	break;
305      case CHAP_SUCCESS:
306      case CHAP_FAILURE:
307	RecvChapResult(bundle, chp, bp, physical);
308	break;
309      }
310    }
311  }
312  mbuf_Free(bp);
313}
314