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/*
* 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 1.6 1996/05/11 20:48:16 phk Exp $
*
* TODO:
*/
#include <sys/types.h>
#include <time.h>
#include "fsm.h"
#include "chap.h"
#include "lcpproto.h"
#include "lcp.h"
#include "hdlc.h"
#include "phase.h"
#include "vars.h"
#include "auth.h"
static char *chapcodes[] = {
"???", "CHALLENGE", "RESPONCE", "SUCCESS", "FAILURE"
};
struct authinfo AuthChapInfo = {
SendChapChallenge,
};
extern char *AuthGetSecret();
void
ChapOutput(code, id, ptr, count)
u_int code, id;
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 = mballoc(plen, MB_FSM);
bcopy(&lh, MBUF_CTOP(bp), sizeof(struct fsmheader));
if (count)
bcopy(ptr, MBUF_CTOP(bp) + sizeof(struct fsmheader), count);
#ifdef DEBUG
DumpBp(bp);
#endif
LogPrintf(LOG_LCP_BIT, "ChapOutput: %s\n", chapcodes[code]);
HdlcOutput(PRI_LINK, PROTO_CHAP, bp);
}
static char challenge_data[80];
static int challenge_len;
void
SendChapChallenge(chapid)
int chapid;
{
int len, i;
char *cp;
srandom(time(NULL));
cp = challenge_data;
*cp++ = challenge_len = random() % 32 + 16;
for (i = 0; i < challenge_len; i++)
*cp++ = random() & 0xff;
len = strlen(VarAuthName);
bcopy(VarAuthName, cp, len);
cp += len;
ChapOutput(CHAP_CHALLENGE, chapid, challenge_data, cp - challenge_data);
}
#ifdef DEBUG
void
DumpDigest(mes, cp, len)
char *mes;
char *cp;
int len;
{
int i;
logprintf("%s: ", mes);
for (i = 0; i < len; i++) {
logprintf(" %02x", *cp++ & 0xff);
}
logprintf("\n");
}
#endif
void
RecvChapTalk(chp, bp)
struct fsmheader *chp;
struct mbuf *bp;
{
int valsize, len;
int arglen, keylen, namelen;
char *cp, *argp, *ap, *name, *digest;
char *keyp;
MD5_CTX context; /* context */
char answer[100];
char cdigest[16];
len = ntohs(chp->length);
#ifdef DEBUG
logprintf("length: %d\n", len);
#endif
arglen = len - sizeof(struct fsmheader);
cp = (char *)MBUF_CTOP(bp);
valsize = *cp++ & 255;
name = cp + valsize;
namelen = arglen - valsize - 1;
name[namelen] = 0;
LogPrintf(LOG_PHASE_BIT, " Valsize = %d, Name = %s\n", valsize, name);
/*
* Get a secret key corresponds to the peer
*/
keyp = AuthGetSecret(SECRETFILE, name, namelen, chp->code == CHAP_RESPONSE);
switch (chp->code) {
case CHAP_CHALLENGE:
if (keyp) {
keylen = strlen(keyp);
} else {
keylen = strlen(VarAuthKey);
keyp = VarAuthKey;
}
name = VarAuthName;
namelen = strlen(VarAuthName);
argp = malloc(1 + valsize + namelen + 16);
digest = argp;
*digest++ = 16; /* value size */
ap = answer;
*ap++ = chp->id;
bcopy(keyp, ap, keylen);
ap += keylen;
bcopy(cp, ap, valsize);
#ifdef DEBUG
DumpDigest("recv", ap, valsize);
#endif
ap += valsize;
MD5Init(&context);
MD5Update(&context, answer, ap - answer);
MD5Final(digest, &context);
#ifdef DEBUG
DumpDigest("answer", digest, 16);
#endif
bcopy(name, digest + 16, namelen);
ap += namelen;
/* Send answer to the peer */
ChapOutput(CHAP_RESPONSE, chp->id, argp, namelen + 17);
free(argp);
break;
case CHAP_RESPONSE:
if (keyp) {
/*
* Compute correct digest value
*/
keylen = strlen(keyp);
ap = answer;
*ap++ = chp->id;
bcopy(keyp, ap, keylen);
ap += keylen;
MD5Init(&context);
MD5Update(&context, answer, ap - answer);
MD5Update(&context, challenge_data+1, challenge_len);
MD5Final(cdigest, &context);
#ifdef DEBUG
DumpDigest("got", cp, 16);
DumpDigest("expect", cdigest, 16);
#endif
/*
* Compare with the response
*/
if (bcmp(cp, cdigest, 16) == 0) {
ChapOutput(CHAP_SUCCESS, chp->id, "Wellcome!!", 10);
NewPhase(PHASE_NETWORK);
break;
}
}
/*
* Peer is not registerd, or response digest is wrong.
*/
ChapOutput(CHAP_FAILURE, chp->id, "Invalid!!", 9);
LcpClose();
break;
}
}
void
RecvChapResult(chp, bp)
struct fsmheader *chp;
struct mbuf *bp;
{
int len;
struct lcpstate *lcp = &LcpInfo;
len = ntohs(chp->length);
#ifdef DEBUG
logprintf("length: %d\n", len);
#endif
if (chp->code == CHAP_SUCCESS) {
if (lcp->auth_iwait == PROTO_CHAP) {
lcp->auth_iwait = 0;
if (lcp->auth_ineed == 0)
NewPhase(PHASE_NETWORK);
}
} else {
/*
* Maybe, we shoud close LCP. Of cause, peer may take close action, too.
*/
;
}
}
void
ChapInput(struct mbuf *bp)
{
int len = plength(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;
LogPrintf(LOG_LCP_BIT, "ChapInput: %s\n", chapcodes[chp->code]);
bp->offset += sizeof(struct fsmheader);
bp->cnt -= sizeof(struct fsmheader);
switch (chp->code) {
case CHAP_RESPONSE:
StopAuthTimer(&AuthChapInfo);
/* Fall into.. */
case CHAP_CHALLENGE:
RecvChapTalk(chp, bp);
break;
case CHAP_SUCCESS:
case CHAP_FAILURE:
RecvChapResult(chp, bp);
break;
}
}
}
pfree(bp);
}
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