/*
* PPP CHAP Module
*
* Written by Toshiharu OHNO (tony-o@iij.ad.jp)
*
* Copyright (C) 1993, Internet Initiative Japan, Inc. All rights reserverd.
*
* Redistribution and use in source and binary forms are permitted
* provided that the above copyright notice and this paragraph are
* duplicated in all such forms and that any documentation,
* advertising materials, and other materials related to such
* distribution and use acknowledge that the software was developed
* by the Internet Initiative Japan, Inc. The name of the
* IIJ may not be used to endorse or promote products derived
* from this software without specific prior written permission.
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
*
* $Id: chap.c,v 1.31 1998/05/21 21:44:25 brian Exp $
*
* TODO:
*/
#include <sys/types.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <sys/un.h>
#include <md4.h>
#include <md5.h>
#include <stdlib.h>
#include <string.h>
#include <termios.h>
#include "mbuf.h"
#include "log.h"
#include "defs.h"
#include "timer.h"
#include "fsm.h"
#include "lcpproto.h"
#include "lcp.h"
#include "lqr.h"
#include "hdlc.h"
#include "auth.h"
#include "chap.h"
#include "async.h"
#include "throughput.h"
#include "descriptor.h"
#include "iplist.h"
#include "slcompress.h"
#include "ipcp.h"
#include "filter.h"
#include "ccp.h"
#include "link.h"
#include "physical.h"
#include "mp.h"
#include "bundle.h"
#include "chat.h"
#include "datalink.h"
#include "chap_ms.h"
static const char *chapcodes[] = {
"???", "CHALLENGE", "RESPONSE", "SUCCESS", "FAILURE"
};
static void
ChapOutput(struct physical *physical, u_int code, u_int id,
const u_char * ptr, int count)
{
int plen;
struct fsmheader lh;
struct mbuf *bp;
plen = sizeof(struct fsmheader) + count;
lh.code = code;
lh.id = id;
lh.length = htons(plen);
bp = mbuf_Alloc(plen, MB_FSM);
memcpy(MBUF_CTOP(bp), &lh, sizeof(struct fsmheader));
if (count)
memcpy(MBUF_CTOP(bp) + sizeof(struct fsmheader), ptr, count);
log_DumpBp(LogDEBUG, "ChapOutput", bp);
log_Printf(LogLCP, "ChapOutput: %s\n", chapcodes[code]);
hdlc_Output(&physical->link, PRI_LINK, PROTO_CHAP, bp);
}
void
chap_SendChallenge(struct authinfo *auth, int chapid, struct physical *physical)
{
struct chap *chap = auth2chap(auth);
int len, i;
char *cp;
randinit();
cp = chap->challenge_data;
*cp++ = chap->challenge_len = random() % 32 + 16;
for (i = 0; i < chap->challenge_len; i++)
*cp++ = random() & 0xff;
len = strlen(physical->dl->bundle->cfg.auth.name);
memcpy(cp, physical->dl->bundle->cfg.auth.name, len);
cp += len;
ChapOutput(physical, CHAP_CHALLENGE, chapid, chap->challenge_data,
cp - chap->challenge_data);
}
static void
RecvChapTalk(struct bundle *bundle, struct fsmheader *chp, struct mbuf *bp,
struct physical *physical)
{
int valsize, len;
int arglen, keylen, namelen;
char *cp, *argp, *ap, *name, *digest;
char *keyp;
MD5_CTX MD5context; /* context for MD5 */
char answer[100];
char cdigest[16];
#ifdef HAVE_DES
int ix;
MD4_CTX MD4context; /* context for MD4 */
#endif
len = ntohs(chp->length);
log_Printf(LogDEBUG, "RecvChapTalk: length: %d\n", len);
arglen = len - sizeof(struct fsmheader);
cp = (char *) MBUF_CTOP(bp);
valsize = *cp++ & 255;
name = cp + valsize;
namelen = arglen - valsize - 1;
name[namelen] = 0;
log_Printf(LogLCP, " Valsize = %d, Name = \"%s\"\n", valsize, name);
switch (chp->code) {
case CHAP_CHALLENGE:
keyp = bundle->cfg.auth.key;
keylen = strlen(bundle->cfg.auth.key);
name = bundle->cfg.auth.name;
namelen = strlen(bundle->cfg.auth.name);
#ifdef HAVE_DES
if (physical->dl->chap.using_MSChap)
argp = malloc(1 + namelen + MS_CHAP_RESPONSE_LEN);
else
#endif
argp = malloc(1 + valsize + namelen + 16);
if (argp == NULL) {
ChapOutput(physical, CHAP_FAILURE, chp->id, "Out of memory!", 14);
return;
}
#ifdef HAVE_DES
if (physical->dl->chap.using_MSChap) {
digest = argp; /* this is the response */
*digest++ = MS_CHAP_RESPONSE_LEN; /* 49 */
memset(digest, '\0', 24);
digest += 24;
ap = answer; /* this is the challenge */
memcpy(ap, keyp, keylen);
ap += 2 * keylen;
memcpy(ap, cp, valsize);
log_DumpBuff(LogDEBUG, "recv", ap, valsize);
ap += valsize;
for (ix = keylen; ix > 0 ; ix--) {
answer[2*ix-2] = answer[ix-1];
answer[2*ix-1] = 0;
}
MD4Init(&MD4context);
MD4Update(&MD4context, answer, 2 * keylen);
MD4Final(digest, &MD4context);
memcpy(digest + 25, name, namelen);
ap += 2 * keylen;
chap_MS(digest, answer + 2 * keylen, valsize);
log_DumpBuff(LogDEBUG, "answer", digest, 24);
ChapOutput(physical, CHAP_RESPONSE, chp->id, argp,
namelen + MS_CHAP_RESPONSE_LEN + 1);
} else {
#endif
digest = argp;
*digest++ = 16; /* value size */
ap = answer;
*ap++ = chp->id;
memcpy(ap, keyp, keylen);
ap += keylen;
memcpy(ap, cp, valsize);
log_DumpBuff(LogDEBUG, "recv", ap, valsize);
ap += valsize;
MD5Init(&MD5context);
MD5Update(&MD5context, answer, ap - answer);
MD5Final(digest, &MD5context);
log_DumpBuff(LogDEBUG, "answer", digest, 16);
memcpy(digest + 16, name, namelen);
ap += namelen;
/* Send answer to the peer */
ChapOutput(physical, CHAP_RESPONSE, chp->id, argp, namelen + 17);
#ifdef HAVE_DES
}
#endif
free(argp);
break;
case CHAP_RESPONSE:
/*
* Get a secret key corresponds to the peer
*/
keyp = auth_GetSecret(bundle, name, namelen, physical);
if (keyp) {
/*
* Compute correct digest value
*/
keylen = strlen(keyp);
ap = answer;
*ap++ = chp->id;
memcpy(ap, keyp, keylen);
ap += keylen;
MD5Init(&MD5context);
MD5Update(&MD5context, answer, ap - answer);
MD5Update(&MD5context, physical->dl->chap.challenge_data + 1,
physical->dl->chap.challenge_len);
MD5Final(cdigest, &MD5context);
log_DumpBuff(LogDEBUG, "got", cp, 16);
log_DumpBuff(LogDEBUG, "expect", cdigest, 16);
/*
* Compare with the response
*/
if (memcmp(cp, cdigest, 16) == 0) {
datalink_GotAuthname(physical->dl, name, namelen);
ChapOutput(physical, CHAP_SUCCESS, chp->id, "Welcome!!", 10);
if (Enabled(bundle, OPT_UTMP))
physical_Login(physical, name);
if (physical->link.lcp.auth_iwait == 0)
/*
* Either I didn't need to authenticate, or I've already been
* told that I got the answer right.
*/
datalink_AuthOk(physical->dl);
break;
}
}
/*
* Peer is not registerd, or response digest is wrong.
*/
ChapOutput(physical, CHAP_FAILURE, chp->id, "Invalid!!", 9);
datalink_AuthNotOk(physical->dl);
break;
}
}
static void
RecvChapResult(struct bundle *bundle, struct fsmheader *chp, struct mbuf *bp,
struct physical *physical)
{
int len;
len = ntohs(chp->length);
log_Printf(LogDEBUG, "RecvChapResult: length: %d\n", len);
if (chp->code == CHAP_SUCCESS) {
if (physical->link.lcp.auth_iwait == PROTO_CHAP) {
physical->link.lcp.auth_iwait = 0;
if (physical->link.lcp.auth_ineed == 0)
/*
* We've succeeded in our ``login''
* If we're not expecting the peer to authenticate (or he already
* has), proceed to network phase.
*/
datalink_AuthOk(physical->dl);
}
} else {
/* CHAP failed - it's not going to get any better */
log_Printf(LogPHASE, "Received CHAP_FAILURE\n");
datalink_AuthNotOk(physical->dl);
}
}
void
chap_Input(struct bundle *bundle, struct mbuf *bp, struct physical *physical)
{
int len = mbuf_Length(bp);
struct fsmheader *chp;
if (len >= sizeof(struct fsmheader)) {
chp = (struct fsmheader *) MBUF_CTOP(bp);
if (len >= ntohs(chp->length)) {
if (chp->code < 1 || chp->code > 4)
chp->code = 0;
log_Printf(LogLCP, "chap_Input: %s\n", chapcodes[chp->code]);
bp->offset += sizeof(struct fsmheader);
bp->cnt -= sizeof(struct fsmheader);
switch (chp->code) {
case CHAP_RESPONSE:
auth_StopTimer(&physical->dl->chap.auth);
/* Fall into.. */
case CHAP_CHALLENGE:
RecvChapTalk(bundle, chp, bp, physical);
break;
case CHAP_SUCCESS:
case CHAP_FAILURE:
RecvChapResult(bundle, chp, bp, physical);
break;
}
}
}
mbuf_Free(bp);
}
