406 lines
11 KiB
C
406 lines
11 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 1.41 1999/02/07 13:48:38 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 <netinet/in_systm.h>
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#include <netinet/ip.h>
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#include <sys/un.h>
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#ifdef HAVE_DES
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#include <md4.h>
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#include <string.h>
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#endif
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#include <md5.h>
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#include <stdlib.h>
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#include <termios.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 "lcpproto.h"
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#include "lcp.h"
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#include "lqr.h"
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#include "hdlc.h"
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#include "auth.h"
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#include "chap.h"
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#include "async.h"
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#include "throughput.h"
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#include "descriptor.h"
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#include "iplist.h"
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#include "slcompress.h"
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#include "ipcp.h"
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#include "filter.h"
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#include "ccp.h"
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#include "link.h"
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#include "physical.h"
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#include "mp.h"
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#ifndef NORADIUS
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#include "radius.h"
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#endif
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#include "bundle.h"
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#include "chat.h"
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#include "cbcp.h"
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#include "datalink.h"
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#ifdef HAVE_DES
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#include "chap_ms.h"
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#endif
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static const char *chapcodes[] = {
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"???", "CHALLENGE", "RESPONSE", "SUCCESS", "FAILURE"
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};
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#define MAXCHAPCODE (sizeof chapcodes / sizeof chapcodes[0] - 1)
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static void
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ChapOutput(struct physical *physical, u_int code, u_int id,
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const u_char *ptr, int count, const char *text)
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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 = mbuf_Alloc(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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log_DumpBp(LogDEBUG, "ChapOutput", bp);
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if (text == NULL)
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log_Printf(LogPHASE, "Chap Output: %s\n", chapcodes[code]);
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else
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log_Printf(LogPHASE, "Chap Output: %s (%s)\n", chapcodes[code], text);
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hdlc_Output(&physical->link, PRI_LINK, PROTO_CHAP, bp);
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}
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static char *
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chap_BuildAnswer(char *name, char *key, u_char id, char *challenge, int MSChap)
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{
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char *result, *digest;
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size_t nlen, klen;
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nlen = strlen(name);
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klen = strlen(key);
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#ifdef HAVE_DES
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if (MSChap) {
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char expkey[AUTHLEN << 2];
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MD4_CTX MD4context;
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int f;
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if ((result = malloc(1 + nlen + MS_CHAP_RESPONSE_LEN)) == NULL)
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return result;
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digest = result; /* 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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for (f = klen; f; f--) {
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expkey[2*f-2] = key[f-1];
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expkey[2*f-1] = 0;
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}
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/*
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* -----------
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* answer = | k\0e\0y\0 |
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* -----------
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*/
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MD4Init(&MD4context);
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MD4Update(&MD4context, expkey, klen << 1);
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MD4Final(digest, &MD4context);
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memcpy(digest + 25, name, nlen);
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/*
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* ``result'' is:
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* ---- --------- -------------------- ------
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* result = | 49 | 24 * \0 | digest (pad to 25) | name |
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* ---- --------- -------------------- ------
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*/
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chap_MS(digest, challenge + 1, *challenge);
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/*
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* ---- --------- ---------------- --- ----------
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* result = | 49 | 24 * \0 | 24 byte digest | 1 | authname |
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* ---- --------- ---------------- --- ----------
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*/
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} else
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#endif
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if ((result = malloc(nlen + 17)) != NULL) {
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/* Normal MD5 stuff */
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MD5_CTX MD5context;
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digest = result;
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*digest++ = 16; /* value size */
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MD5Init(&MD5context);
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MD5Update(&MD5context, &id, 1);
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MD5Update(&MD5context, key, klen);
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MD5Update(&MD5context, challenge + 1, *challenge);
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MD5Final(digest, &MD5context);
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memcpy(digest + 16, name, nlen);
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/*
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* ---- -------- ------
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* result = | 16 | digest | name |
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* ---- -------- ------
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*/
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}
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return result;
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}
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static void
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chap_Challenge(struct authinfo *authp)
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{
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struct chap *chap = auth2chap(authp);
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int len, i;
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char *cp;
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randinit();
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cp = chap->challenge;
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#ifndef NORADIUS
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if (*authp->physical->dl->bundle->radius.cfg.file) {
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/* For radius, our challenge is 16 readable NUL terminated bytes :*/
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*cp++ = 16;
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for (i = 0; i < 16; i++)
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*cp++ = (random() % 10) + '0';
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} else
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#endif
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{
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*cp++ = random() % (CHAPCHALLENGELEN-16) + 16;
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for (i = 0; i < *chap->challenge; i++)
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*cp++ = random() & 0xff;
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}
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len = strlen(authp->physical->dl->bundle->cfg.auth.name);
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memcpy(cp, authp->physical->dl->bundle->cfg.auth.name, len);
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cp += len;
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ChapOutput(authp->physical, CHAP_CHALLENGE, authp->id, chap->challenge,
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cp - chap->challenge, NULL);
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}
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static void
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chap_Success(struct authinfo *authp)
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{
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datalink_GotAuthname(authp->physical->dl, authp->in.name);
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ChapOutput(authp->physical, CHAP_SUCCESS, authp->id, "Welcome!!", 10, NULL);
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authp->physical->link.lcp.auth_ineed = 0;
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if (Enabled(authp->physical->dl->bundle, OPT_UTMP))
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physical_Login(authp->physical, authp->in.name);
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if (authp->physical->link.lcp.auth_iwait == 0)
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/*
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* Either I didn't need to authenticate, or I've already been
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* told that I got the answer right.
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*/
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datalink_AuthOk(authp->physical->dl);
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}
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static void
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chap_Failure(struct authinfo *authp)
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{
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ChapOutput(authp->physical, CHAP_FAILURE, authp->id, "Invalid!!", 9, NULL);
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datalink_AuthNotOk(authp->physical->dl);
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}
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void
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chap_Init(struct chap *chap, struct physical *p)
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{
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auth_Init(&chap->auth, p, chap_Challenge, chap_Success, chap_Failure);
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*chap->challenge = 0;
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chap->using_MSChap = 0;
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}
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void
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chap_Input(struct physical *p, struct mbuf *bp)
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{
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struct chap *chap = &p->dl->chap;
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char *name, *key, *ans, *myans;
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int len, nlen;
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u_char alen;
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if ((bp = auth_ReadHeader(&chap->auth, bp)) == NULL)
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log_Printf(LogERROR, "Chap Input: Truncated header !\n");
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else if (chap->auth.in.hdr.code == 0 || chap->auth.in.hdr.code > MAXCHAPCODE)
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log_Printf(LogPHASE, "Chap Input: %d: Bad CHAP code !\n",
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chap->auth.in.hdr.code);
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else {
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len = mbuf_Length(bp);
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ans = NULL;
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if (chap->auth.in.hdr.code != CHAP_CHALLENGE &&
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chap->auth.id != chap->auth.in.hdr.id &&
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Enabled(p->dl->bundle, OPT_IDCHECK)) {
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/* Wrong conversation dude ! */
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log_Printf(LogPHASE, "Chap Input: %s dropped (got id %d, not %d)\n",
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chapcodes[chap->auth.in.hdr.code], chap->auth.in.hdr.id,
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chap->auth.id);
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mbuf_Free(bp);
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return;
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}
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chap->auth.id = chap->auth.in.hdr.id; /* We respond with this id */
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switch (chap->auth.in.hdr.code) {
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case CHAP_CHALLENGE:
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bp = mbuf_Read(bp, chap->challenge, 1);
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len -= *chap->challenge + 1;
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if (len < 0) {
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log_Printf(LogERROR, "Chap Input: Truncated challenge !\n");
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mbuf_Free(bp);
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return;
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}
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bp = mbuf_Read(bp, chap->challenge + 1, *chap->challenge);
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bp = auth_ReadName(&chap->auth, bp, len);
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break;
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case CHAP_RESPONSE:
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auth_StopTimer(&chap->auth);
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bp = mbuf_Read(bp, &alen, 1);
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len -= alen + 1;
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if (len < 0) {
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log_Printf(LogERROR, "Chap Input: Truncated response !\n");
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mbuf_Free(bp);
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return;
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}
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if ((ans = malloc(alen + 2)) == NULL) {
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log_Printf(LogERROR, "Chap Input: Out of memory !\n");
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mbuf_Free(bp);
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return;
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}
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*ans = chap->auth.id;
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bp = mbuf_Read(bp, ans + 1, alen);
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ans[alen+1] = '\0';
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bp = auth_ReadName(&chap->auth, bp, len);
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break;
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case CHAP_SUCCESS:
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case CHAP_FAILURE:
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/* chap->auth.in.name is already set up at CHALLENGE time */
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if ((ans = malloc(len + 1)) == NULL) {
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log_Printf(LogERROR, "Chap Input: Out of memory !\n");
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mbuf_Free(bp);
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return;
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}
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bp = mbuf_Read(bp, ans, len);
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ans[len] = '\0';
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break;
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}
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switch (chap->auth.in.hdr.code) {
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case CHAP_CHALLENGE:
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case CHAP_RESPONSE:
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if (*chap->auth.in.name)
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log_Printf(LogPHASE, "Chap Input: %s (from %s)\n",
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chapcodes[chap->auth.in.hdr.code], chap->auth.in.name);
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else
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log_Printf(LogPHASE, "Chap Input: %s\n",
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chapcodes[chap->auth.in.hdr.code]);
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break;
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case CHAP_SUCCESS:
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case CHAP_FAILURE:
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if (*ans)
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log_Printf(LogPHASE, "Chap Input: %s (%s)\n",
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chapcodes[chap->auth.in.hdr.code], ans);
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else
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log_Printf(LogPHASE, "Chap Input: %s\n",
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chapcodes[chap->auth.in.hdr.code]);
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break;
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}
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switch (chap->auth.in.hdr.code) {
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case CHAP_CHALLENGE:
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name = p->dl->bundle->cfg.auth.name;
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nlen = strlen(name);
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key = p->dl->bundle->cfg.auth.key;
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myans = chap_BuildAnswer(name, key, chap->auth.id, chap->challenge, 0);
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if (myans) {
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ChapOutput(p, CHAP_RESPONSE, chap->auth.id, myans,
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*myans + 1 + nlen, name);
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free(myans);
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} else
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ChapOutput(p, CHAP_FAILURE, chap->auth.id, "Out of memory!",
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14, NULL);
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break;
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case CHAP_RESPONSE:
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name = chap->auth.in.name;
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nlen = strlen(name);
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#ifndef NORADIUS
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if (*p->dl->bundle->radius.cfg.file) {
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chap->challenge[*chap->challenge+1] = '\0';
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radius_Authenticate(&p->dl->bundle->radius, &chap->auth,
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chap->auth.in.name, ans, chap->challenge + 1);
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} else
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#endif
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{
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key = auth_GetSecret(p->dl->bundle, name, nlen, p);
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if (key) {
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myans = chap_BuildAnswer(name, key, chap->auth.id, chap->challenge,
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chap->using_MSChap);
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if (myans == NULL)
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key = NULL;
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else {
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if (*myans != alen || memcmp(myans + 1, ans + 1, *myans))
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key = NULL;
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free(myans);
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}
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}
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if (key)
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chap_Success(&chap->auth);
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else
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chap_Failure(&chap->auth);
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}
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break;
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case CHAP_SUCCESS:
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if (p->link.lcp.auth_iwait == PROTO_CHAP) {
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p->link.lcp.auth_iwait = 0;
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if (p->link.lcp.auth_ineed == 0)
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/*
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* We've succeeded in our ``login''
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* If we're not expecting the peer to authenticate (or he already
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* has), proceed to network phase.
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*/
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datalink_AuthOk(p->dl);
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}
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break;
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case CHAP_FAILURE:
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datalink_AuthNotOk(p->dl);
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break;
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}
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free(ans);
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}
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mbuf_Free(bp);
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}
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