312 lines
7.8 KiB
C
312 lines
7.8 KiB
C
/*
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* PPP CHAP Module
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*
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* Written by Toshiharu OHNO (tony-o@iij.ad.jp)
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*
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* Copyright (C) 1993, Internet Initiative Japan, Inc. All rights reserverd.
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*
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* Redistribution and use in source and binary forms are permitted
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* provided that the above copyright notice and this paragraph are
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* duplicated in all such forms and that any documentation,
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* advertising materials, and other materials related to such
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* distribution and use acknowledge that the software was developed
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* by the Internet Initiative Japan, Inc. The name of the
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* IIJ may not be used to endorse or promote products derived
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* from this software without specific prior written permission.
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
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* WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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*
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* $Id: chap.c,v 1.29 1998/02/19 02:10:06 brian Exp $
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*
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* TODO:
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*/
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#include <sys/param.h>
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#include <netinet/in.h>
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#include <ctype.h>
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#ifdef HAVE_DES
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#include <md4.h>
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#endif
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#include <md5.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <time.h>
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#include <unistd.h>
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#ifdef __OpenBSD__
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#include <util.h>
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#else
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#include <libutil.h>
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#endif
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#include <utmp.h>
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#include "command.h"
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#include "mbuf.h"
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#include "log.h"
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#include "defs.h"
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#include "timer.h"
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#include "fsm.h"
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#include "chap.h"
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#include "chap_ms.h"
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#include "lcpproto.h"
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#include "lcp.h"
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#include "hdlc.h"
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#include "phase.h"
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#include "loadalias.h"
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#include "vars.h"
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#include "auth.h"
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#include "id.h"
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static const char *chapcodes[] = {
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"???", "CHALLENGE", "RESPONSE", "SUCCESS", "FAILURE"
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};
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static void
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ChapOutput(u_int code, u_int id, const u_char * ptr, int count)
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{
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int plen;
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struct fsmheader lh;
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struct mbuf *bp;
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plen = sizeof(struct fsmheader) + count;
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lh.code = code;
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lh.id = id;
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lh.length = htons(plen);
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bp = mballoc(plen, MB_FSM);
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memcpy(MBUF_CTOP(bp), &lh, sizeof(struct fsmheader));
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if (count)
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memcpy(MBUF_CTOP(bp) + sizeof(struct fsmheader), ptr, count);
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LogDumpBp(LogDEBUG, "ChapOutput", bp);
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LogPrintf(LogLCP, "ChapOutput: %s\n", chapcodes[code]);
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HdlcOutput(PRI_LINK, PROTO_CHAP, bp);
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}
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static char challenge_data[80];
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static int challenge_len;
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static void
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SendChapChallenge(int chapid)
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{
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int len, i;
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char *cp;
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randinit();
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cp = challenge_data;
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*cp++ = challenge_len = random() % 32 + 16;
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for (i = 0; i < challenge_len; i++)
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*cp++ = random() & 0xff;
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len = strlen(VarAuthName);
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memcpy(cp, VarAuthName, len);
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cp += len;
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ChapOutput(CHAP_CHALLENGE, chapid, challenge_data, cp - challenge_data);
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}
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struct authinfo AuthChapInfo = {
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SendChapChallenge,
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};
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static void
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RecvChapTalk(struct fsmheader *chp, struct mbuf *bp)
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{
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int valsize, len;
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int arglen, keylen, namelen;
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char *cp, *argp, *ap, *name, *digest;
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char *keyp;
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MD5_CTX MD5context; /* context for MD5 */
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char answer[100];
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char cdigest[16];
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#ifdef HAVE_DES
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int ix;
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MD4_CTX MD4context; /* context for MD4 */
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#endif
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len = ntohs(chp->length);
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LogPrintf(LogDEBUG, "RecvChapTalk: length: %d\n", len);
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arglen = len - sizeof(struct fsmheader);
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cp = (char *) MBUF_CTOP(bp);
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valsize = *cp++ & 255;
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name = cp + valsize;
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namelen = arglen - valsize - 1;
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name[namelen] = 0;
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LogPrintf(LogLCP, " Valsize = %d, Name = \"%s\"\n", valsize, name);
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switch (chp->code) {
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case CHAP_CHALLENGE:
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keyp = VarAuthKey;
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keylen = strlen(VarAuthKey);
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name = VarAuthName;
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namelen = strlen(VarAuthName);
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#ifdef HAVE_DES
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if (VarMSChap)
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argp = malloc(1 + namelen + MS_CHAP_RESPONSE_LEN);
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else
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#endif
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argp = malloc(1 + valsize + namelen + 16);
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if (argp == NULL) {
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ChapOutput(CHAP_FAILURE, chp->id, "Out of memory!", 14);
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return;
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}
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#ifdef HAVE_DES
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if (VarMSChap) {
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digest = argp; /* this is the response */
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*digest++ = MS_CHAP_RESPONSE_LEN; /* 49 */
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memset(digest, '\0', 24);
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digest += 24;
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ap = answer; /* this is the challenge */
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memcpy(ap, keyp, keylen);
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ap += 2 * keylen;
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memcpy(ap, cp, valsize);
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LogDumpBuff(LogDEBUG, "recv", ap, valsize);
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ap += valsize;
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for (ix = keylen; ix > 0 ; ix--) {
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answer[2*ix-2] = answer[ix-1];
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answer[2*ix-1] = 0;
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}
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MD4Init(&MD4context);
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MD4Update(&MD4context, answer, 2 * keylen);
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MD4Final(digest, &MD4context);
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memcpy(digest + 25, name, namelen);
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ap += 2 * keylen;
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ChapMS(digest, answer + 2 * keylen, valsize);
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LogDumpBuff(LogDEBUG, "answer", digest, 24);
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ChapOutput(CHAP_RESPONSE, chp->id, argp, namelen + MS_CHAP_RESPONSE_LEN + 1);
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} else {
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#endif
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digest = argp;
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*digest++ = 16; /* value size */
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ap = answer;
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*ap++ = chp->id;
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memcpy(ap, keyp, keylen);
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ap += keylen;
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memcpy(ap, cp, valsize);
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LogDumpBuff(LogDEBUG, "recv", ap, valsize);
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ap += valsize;
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MD5Init(&MD5context);
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MD5Update(&MD5context, answer, ap - answer);
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MD5Final(digest, &MD5context);
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LogDumpBuff(LogDEBUG, "answer", digest, 16);
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memcpy(digest + 16, name, namelen);
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ap += namelen;
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/* Send answer to the peer */
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ChapOutput(CHAP_RESPONSE, chp->id, argp, namelen + 17);
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#ifdef HAVE_DES
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}
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#endif
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free(argp);
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break;
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case CHAP_RESPONSE:
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/*
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* Get a secret key corresponds to the peer
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*/
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keyp = AuthGetSecret(SECRETFILE, name, namelen, chp->code == CHAP_RESPONSE);
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if (keyp) {
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/*
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* Compute correct digest value
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*/
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keylen = strlen(keyp);
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ap = answer;
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*ap++ = chp->id;
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memcpy(ap, keyp, keylen);
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ap += keylen;
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MD5Init(&MD5context);
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MD5Update(&MD5context, answer, ap - answer);
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MD5Update(&MD5context, challenge_data + 1, challenge_len);
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MD5Final(cdigest, &MD5context);
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LogDumpBuff(LogDEBUG, "got", cp, 16);
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LogDumpBuff(LogDEBUG, "expect", cdigest, 16);
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/*
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* Compare with the response
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*/
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if (memcmp(cp, cdigest, 16) == 0) {
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ChapOutput(CHAP_SUCCESS, chp->id, "Welcome!!", 10);
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if ((mode & MODE_DIRECT) && isatty(modem) && Enabled(ConfUtmp)) {
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if (Utmp)
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LogPrintf(LogERROR, "Oops, already logged in on %s\n",
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VarBaseDevice);
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else {
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struct utmp ut;
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memset(&ut, 0, sizeof ut);
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time(&ut.ut_time);
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strncpy(ut.ut_name, name, sizeof ut.ut_name);
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strncpy(ut.ut_line, VarBaseDevice, sizeof ut.ut_line - 1);
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ID0login(&ut);
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Utmp = 1;
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}
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}
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NewPhase(PHASE_NETWORK);
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break;
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}
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}
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/*
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* Peer is not registerd, or response digest is wrong.
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*/
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ChapOutput(CHAP_FAILURE, chp->id, "Invalid!!", 9);
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reconnect(RECON_FALSE);
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LcpClose();
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break;
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}
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}
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static void
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RecvChapResult(struct fsmheader *chp, struct mbuf *bp)
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{
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int len;
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struct lcpstate *lcp = &LcpInfo;
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len = ntohs(chp->length);
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LogPrintf(LogDEBUG, "RecvChapResult: length: %d\n", len);
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if (chp->code == CHAP_SUCCESS) {
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if (lcp->auth_iwait == PROTO_CHAP) {
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lcp->auth_iwait = 0;
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if (lcp->auth_ineed == 0)
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NewPhase(PHASE_NETWORK);
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}
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} else {
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/*
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* Maybe, we shoud close LCP. Of cause, peer may take close action, too.
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*/
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;
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}
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}
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void
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ChapInput(struct mbuf *bp)
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{
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int len = plength(bp);
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struct fsmheader *chp;
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if (len >= sizeof(struct fsmheader)) {
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chp = (struct fsmheader *) MBUF_CTOP(bp);
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if (len >= ntohs(chp->length)) {
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if (chp->code < 1 || chp->code > 4)
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chp->code = 0;
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LogPrintf(LogLCP, "ChapInput: %s\n", chapcodes[chp->code]);
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bp->offset += sizeof(struct fsmheader);
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bp->cnt -= sizeof(struct fsmheader);
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switch (chp->code) {
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case CHAP_RESPONSE:
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StopAuthTimer(&AuthChapInfo);
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/* Fall into.. */
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case CHAP_CHALLENGE:
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RecvChapTalk(chp, bp);
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break;
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case CHAP_SUCCESS:
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case CHAP_FAILURE:
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RecvChapResult(chp, bp);
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break;
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}
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}
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}
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pfree(bp);
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}
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