[unix-history] / usr / src / lib / libtelnet / kerberos.c

/*-
 * Copyright (c) 1991 The Regents of the University of California.
 * All rights reserved.
 *
 * %sccs.include.redist.c%
 */

#ifndef lint
static char sccsid[] = "@(#)kerberos.c	5.2 (Berkeley) %G%";
#endif /* not lint */

/*
 * Copyright (C) 1990 by the Massachusetts Institute of Technology
 *
 * Export of this software from the United States of America is assumed
 * to require a specific license from the United States Government.
 * It is the responsibility of any person or organization contemplating
 * export to obtain such a license before exporting.
 *
 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
 * distribute this software and its documentation for any purpose and
 * without fee is hereby granted, provided that the above copyright
 * notice appear in all copies and that both that copyright notice and
 * this permission notice appear in supporting documentation, and that
 * the name of M.I.T. not be used in advertising or publicity pertaining
 * to distribution of the software without specific, written prior
 * permission.  M.I.T. makes no representations about the suitability of
 * this software for any purpose.  It is provided "as is" without express
 * or implied warranty.
 */

#ifdef	KRB4
#include <sys/types.h>
#include <arpa/telnet.h>
#include <stdio.h>
#if	defined(ENCRYPT)
#define	__NEED_ENCRYPT__
#undef	ENCRYPT
#endif
#include <des.h>        /* BSD wont include this in krb.h, so we do it here */
#include <krb.h>
#if	defined(__NEED_ENCRYPT__) && !defined(ENCRYPT)
#define	ENCRYPT
#undef	__NEED_ENCRYPT__
#endif
#ifdef	__STDC__
#include <stdlib.h>
#endif
#ifdef	NO_STRING_H
#include <strings.h>
#else
#include <string.h>
#endif

#include "encrypt.h"
#include "auth.h"
#include "misc.h"

int cksum P((unsigned char *, int));
int krb_mk_req P((KTEXT, char *, char *, char *, u_long));
int krb_rd_req P((KTEXT, char *, char *, u_long, AUTH_DAT *, char *));
int krb_kntoln P((AUTH_DAT *, char *));
int krb_get_cred P((char *, char *, char *, CREDENTIALS *));
int krb_get_lrealm P((char *, int));
int kuserok P((AUTH_DAT *, char *));

extern auth_debug_mode;

static unsigned char str_data[1024] = { IAC, SB, TELOPT_AUTHENTICATION, 0,
			  		AUTHTYPE_KERBEROS_V4, };
static unsigned char str_name[1024] = { IAC, SB, TELOPT_AUTHENTICATION,
					TELQUAL_NAME, };

#define	KRB_AUTH	0		/* Authentication data follows */
#define	KRB_REJECT	1		/* Rejected (reason might follow) */
#define	KRB_ACCEPT	2		/* Accepted */
#define	KRB_CHALLANGE	3		/* Challange for mutual auth. */
#define	KRB_RESPONSE	4		/* Response for mutual auth. */

static	KTEXT_ST auth;
static	char name[ANAME_SZ];
static	AUTH_DAT adat = { 0 };
#if	defined(ENCRYPT)
static Block	session_key	= { 0 };
#endif
static Schedule sched;
static Block	challange	= { 0 };

	static int
Data(ap, type, d, c)
	Authenticator *ap;
	int type;
	void *d;
	int c;
{
        unsigned char *p = str_data + 4;
	unsigned char *cd = (unsigned char *)d;

	if (c == -1)
		c = strlen((char *)cd);

        if (auth_debug_mode) {
                printf("%s:%d: [%d] (%d)",
                        str_data[3] == TELQUAL_IS ? ">>>IS" : ">>>REPLY",
                        str_data[3],
                        type, c);
                printd(d, c);
                printf("\r\n");
        }
	*p++ = ap->type;
	*p++ = ap->way;
	*p++ = type;
        while (c-- > 0) {
                if ((*p++ = *cd++) == IAC)
                        *p++ = IAC;
        }
        *p++ = IAC;
        *p++ = SE;
	if (str_data[3] == TELQUAL_IS)
		printsub('>', &str_data[2], p - (&str_data[2]));
        return(net_write(str_data, p - str_data));
}

	int
kerberos4_init(ap, server)
	Authenticator *ap;
	int server;
{
	if (server)
		str_data[3] = TELQUAL_REPLY;
	else
		str_data[3] = TELQUAL_IS;
	return(1);
}

char dst_realm_buf[REALM_SZ], *dest_realm = NULL;
int dst_realm_sz = REALM_SZ;

	int
kerberos4_send(ap)
	Authenticator *ap;
{
	KTEXT_ST auth;
	Block enckey;
	char instance[INST_SZ];
	char *realm;
	char *krb_realmofhost();
	char *krb_get_phost();
	CREDENTIALS cred;
	int r;
	
	if (!UserNameRequested) {
		if (auth_debug_mode) {
			printf("Kerberos V4: no user name supplied\r\n");
		}
		return(0);
	}

	bzero(instance, sizeof(instance));
	if (realm = krb_get_phost(RemoteHostName))
		strncpy(instance, realm, sizeof(instance));
	instance[sizeof(instance)-1] = '\0';

	realm = dest_realm ? dest_realm : krb_realmofhost(RemoteHostName);
	if (!realm) {
		if (auth_debug_mode) {
			printf("Kerberos V4: no realm for %s\r\n", RemoteHostName);
		}
		return(0);
	}
	if (r = krb_mk_req(&auth, "rcmd", instance, realm, 0L)) {
		if (auth_debug_mode) {
			printf("mk_req failed: %s\r\n", krb_err_txt[r]);
		}
		return(0);
	}
	if (r = krb_get_cred("rcmd", instance, realm, &cred)) {
		if (auth_debug_mode) {
			printf("get_cred failed: %s\r\n", krb_err_txt[r]);
		}
		return(0);
	}
	if (!auth_sendname(UserNameRequested, strlen(UserNameRequested))) {
		if (auth_debug_mode)
			printf("Not enough room for user name\r\n");
		return(0);
	}
	if (auth_debug_mode)
		printf("Sent %d bytes of authentication data\r\n", auth.length);
	if (!Data(ap, KRB_AUTH, (void *)auth.dat, auth.length)) {
		if (auth_debug_mode)
			printf("Not enough room for authentication data\r\n");
		return(0);
	}
	/*
	 * If we are doing mutual authentication, get set up to send
	 * the challange, and verify it when the response comes back.
	 */
	if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL) {
		register int i;

		des_key_sched(cred.session, sched);
		des_set_random_generator_seed(cred.session);
		des_new_random_key(challange);
		des_ecb_encrypt(challange, session_key, sched, 1);
		/*
		 * Increment the challange by 1, and encrypt it for
		 * later comparison.
		 */
		for (i = 7; i >= 0; --i) {
			register int x;
			x = (unsigned int)challange[i] + 1;
			challange[i] = x;	/* ignore overflow */
			if (x < 256)		/* if no overflow, all done */
				break;
		}
		des_ecb_encrypt(challange, challange, sched, 1);
	}
	
	if (auth_debug_mode) {
		printf("CK: %d:", cksum(auth.dat, auth.length));
		printd(auth.dat, auth.length);
		printf("\r\n");
		printf("Sent Kerberos V4 credentials to server\r\n");
	}
	return(1);
}

	void
kerberos4_is(ap, data, cnt)
	Authenticator *ap;
	unsigned char *data;
	int cnt;
{
	Session_Key skey;
	Block datablock;
	char realm[REALM_SZ];
	char instance[INST_SZ];
	int r;

	if (cnt-- < 1)
		return;
	switch (*data++) {
	case KRB_AUTH:
		if (krb_get_lrealm(realm, 1) != KSUCCESS) {
			Data(ap, KRB_REJECT, (void *)"No local V4 Realm.", -1);
			auth_finished(ap, AUTH_REJECT);
			if (auth_debug_mode)
				printf("No local realm\r\n");
			return;
		}
		bcopy((void *)data, (void *)auth.dat, auth.length = cnt);
		if (auth_debug_mode) {
			printf("Got %d bytes of authentication data\r\n", cnt);
			printf("CK: %d:", cksum(auth.dat, auth.length));
			printd(auth.dat, auth.length);
			printf("\r\n");
		}
		instance[0] = '*'; instance[1] = 0;
		if (r = krb_rd_req(&auth, "rcmd", instance, 0, &adat, "")) {
			if (auth_debug_mode)
				printf("Kerberos failed him as %s\r\n", name);
			Data(ap, KRB_REJECT, (void *)krb_err_txt[r], -1);
			auth_finished(ap, AUTH_REJECT);
			return;
		}
		bcopy((void *)adat.session, (void *)session_key, sizeof(Block));
		krb_kntoln(&adat, name);
		Data(ap, KRB_ACCEPT, (void *)0, 0);
		auth_finished(ap, AUTH_USER);
		if (auth_debug_mode) {
			printf("Kerberos accepting him as %s\r\n", name);
		}
		break;

	case KRB_CHALLANGE:
		if (!VALIDKEY(session_key)) {
			/*
			 * We don't have a valid session key, so just
			 * send back a response with an empty session
			 * key.
			 */
			Data(ap, KRB_RESPONSE, (void *)0, 0);
			break;
		}

		des_key_sched(session_key, sched);
		bcopy((void *)data, (void *)datablock, sizeof(Block));
		/*
		 * Take the received encrypted challange, and encrypt
		 * it again to get a unique session_key for the
		 * ENCRYPT option.
		 */
		des_ecb_encrypt(datablock, session_key, sched, 1);
		skey.type = SK_DES;
		skey.length = 8;
		skey.data = session_key;
		encrypt_session_key(&skey, 1);
		/*
		 * Now decrypt the received encrypted challange,
		 * increment by one, re-encrypt it and send it back.
		 */
		des_ecb_encrypt(datablock, challange, sched, 0);
		for (r = 7; r >= 0; r++) {
			register int t;
			t = (unsigned int)challange[r] + 1;
			challange[r] = t;	/* ignore overflow */
			if (t < 256)		/* if no overflow, all done */
				break;
		}
		des_ecb_encrypt(challange, challange, sched, 1);
		Data(ap, KRB_RESPONSE, (void *)challange, sizeof(challange));
		break;

	default:
		if (auth_debug_mode)
			printf("Unknown Kerberos option %d\r\n", data[-1]);
		Data(ap, KRB_REJECT, 0, 0);
		break;
	}
}

	void
kerberos4_reply(ap, data, cnt)
	Authenticator *ap;
	unsigned char *data;
	int cnt;
{
	Session_Key skey;

	if (cnt-- < 1)
		return;
	switch (*data++) {
	case KRB_REJECT:
		if (cnt > 0) {
			printf("[ Kerberos V4 refuses authentication because %.*s ]\r\n",
				cnt, data);
		} else
			printf("[ Kerberos V4 refuses authentication ]\r\n");
		auth_send_retry();
		return;
	case KRB_ACCEPT:
		printf("[ Kerberos V4 accepts you ]\n");
		if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL) {
			/*
			 * Send over the encrypted challange.
		 	 */
			Data(ap, KRB_CHALLANGE, (void *)session_key,
						sizeof(session_key));
#if	defined(ENCRYPT)
			des_ecb_encrypt(session_key, session_key, sched, 1);
			skey.type = SK_DES;
			skey.length = 8;
			skey.data = session_key;
			encrypt_session_key(&skey, 0);
#endif
			return;
		}
		auth_finished(ap, AUTH_USER);
		return;
	case KRB_RESPONSE:
		/*
		 * Verify that the response to the challange is correct.
		 */
		if ((cnt != sizeof(Block)) ||
		    (0 != memcmp((void *)data, (void *)challange,
						sizeof(challange))))
		{
			printf("[ Kerberos V4 challange failed!!! ]\r\n");
			auth_send_retry();
			return;
		}
		printf("[ Kerberos V4 challange successful ]\r\n");
		auth_finished(ap, AUTH_USER);
		break;
	default:
		if (auth_debug_mode)
			printf("Unknown Kerberos option %d\r\n", data[-1]);
		return;
	}
}

	int
kerberos4_status(ap, name, level)
	Authenticator *ap;
	char *name;
	int level;
{
	if (level < AUTH_USER)
		return(level);

	if (UserNameRequested && !kuserok(&adat, UserNameRequested)) {
		strcpy(name, UserNameRequested);
		return(AUTH_VALID);
	} else
		return(AUTH_USER);
}

#define	BUMP(buf, len)		while (*(buf)) {++(buf), --(len);}
#define	ADDC(buf, len, c)	if ((len) > 0) {*(buf)++ = (c); --(len);}

	void
kerberos4_printsub(data, cnt, buf, buflen)
	unsigned char *data, *buf;
	int cnt, buflen;
{
	char lbuf[32];
	register int i;

	buf[buflen-1] = '\0';		/* make sure its NULL terminated */
	buflen -= 1;

	switch(data[3]) {
	case KRB_REJECT:		/* Rejected (reason might follow) */
		strncpy((char *)buf, " REJECT ", buflen);
		goto common;

	case KRB_ACCEPT:		/* Accepted (name might follow) */
		strncpy((char *)buf, " ACCEPT ", buflen);
	common:
		BUMP(buf, buflen);
		if (cnt <= 4)
			break;
		ADDC(buf, buflen, '"');
		for (i = 4; i < cnt; i++)
			ADDC(buf, buflen, data[i]);
		ADDC(buf, buflen, '"');
		ADDC(buf, buflen, '\0');
		break;

	case KRB_AUTH:			/* Authentication data follows */
		strncpy((char *)buf, " AUTH", buflen);
		goto common2;

	case KRB_CHALLANGE:
		strncpy((char *)buf, " CHALLANGE", buflen);
		goto common2;

	case KRB_RESPONSE:
		strncpy((char *)buf, " RESPONSE", buflen);
		goto common2;

	default:
		sprintf(lbuf, " %d (unknown)", data[3]);
		strncpy((char *)buf, lbuf, buflen);
	common2:
		BUMP(buf, buflen);
		for (i = 4; i < cnt; i++) {
			sprintf(lbuf, " %d", data[i]);
			strncpy((char *)buf, lbuf, buflen);
			BUMP(buf, buflen);
		}
		break;
	}
}

	int
cksum(d, n)
	unsigned char *d;
	int n;
{
	int ck = 0;

	switch (n&03)
	while (n > 0) {
	case 0:
		ck ^= *d++ << 24;
		--n;
	case 3:
		ck ^= *d++ << 16;
		--n;
	case 2:
		ck ^= *d++ << 8;
		--n;
	case 1:
		ck ^= *d++;
		--n;
	}
	return(ck);
}
#endif

#ifdef notdef

prkey(msg, key)
	char *msg;
	unsigned char *key;
{
	register int i;
	printf("%s:", msg);
	for (i = 0; i < 8; i++)
		printf(" %3d", key[i]);
	printf("\r\n");
}
#endif
Commit	Line	Data
54b7f482 DB	1	/*-
	2	* Copyright (c) 1991 The Regents of the University of California.
	3	* All rights reserved.
	4	*
	5	* %sccs.include.redist.c%
	6	*/
	7
	8	#ifndef lint
b7c8f459	9	static char sccsid[] = "@(#)kerberos.c 5.2 (Berkeley) %G%";
54b7f482 DB	10	#endif /* not lint */
	11
	12	/*
	13	* Copyright (C) 1990 by the Massachusetts Institute of Technology
	14	*
	15	* Export of this software from the United States of America is assumed
	16	* to require a specific license from the United States Government.
	17	* It is the responsibility of any person or organization contemplating
	18	* export to obtain such a license before exporting.
	19	*
	20	* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
	21	* distribute this software and its documentation for any purpose and
	22	* without fee is hereby granted, provided that the above copyright
	23	* notice appear in all copies and that both that copyright notice and
	24	* this permission notice appear in supporting documentation, and that
	25	* the name of M.I.T. not be used in advertising or publicity pertaining
	26	* to distribution of the software without specific, written prior
	27	* permission. M.I.T. makes no representations about the suitability of
	28	* this software for any purpose. It is provided "as is" without express
	29	* or implied warranty.
	30	*/
	31
	32	#ifdef KRB4
	33	#include <sys/types.h>
	34	#include <arpa/telnet.h>
	35	#include <stdio.h>
	36	#if defined(ENCRYPT)
	37	#define __NEED_ENCRYPT__
	38	#undef ENCRYPT
	39	#endif
	40	#include <des.h> /* BSD wont include this in krb.h, so we do it here */
	41	#include <krb.h>
	42	#if defined(__NEED_ENCRYPT__) && !defined(ENCRYPT)
	43	#define ENCRYPT
	44	#undef __NEED_ENCRYPT__
	45	#endif
	46	#ifdef __STDC__
	47	#include <stdlib.h>
	48	#endif
	49	#ifdef NO_STRING_H
	50	#include <strings.h>
	51	#else
	52	#include <string.h>
	53	#endif
	54
	55	#include "encrypt.h"
	56	#include "auth.h"
	57	#include "misc.h"
	58
	59	int cksum P((unsigned char *, int));
	60	int krb_mk_req P((KTEXT, char , char , char *, u_long));
	61	int krb_rd_req P((KTEXT, char , char , u_long, AUTH_DAT , char ));
	62	int krb_kntoln P((AUTH_DAT , char ));
	63	int krb_get_cred P((char , char , char , CREDENTIALS ));
	64	int krb_get_lrealm P((char *, int));
	65	int kuserok P((AUTH_DAT , char ));
	66
	67	extern auth_debug_mode;
	68
	69	static unsigned char str_data[1024] = { IAC, SB, TELOPT_AUTHENTICATION, 0,
	70	AUTHTYPE_KERBEROS_V4, };
b7c8f459 DB	71	static unsigned char str_name[1024] = { IAC, SB, TELOPT_AUTHENTICATION,
b7c8f459 DB	72	TELQUAL_NAME, };
54b7f482 DB	73
	74	#define KRB_AUTH 0 /* Authentication data follows */
	75	#define KRB_REJECT 1 /* Rejected (reason might follow) */
b7c8f459 DB	76	#define KRB_ACCEPT 2 /* Accepted */
	77	#define KRB_CHALLANGE 3 /* Challange for mutual auth. */
	78	#define KRB_RESPONSE 4 /* Response for mutual auth. */
54b7f482 DB	79
	80	static KTEXT_ST auth;
	81	static char name[ANAME_SZ];
	82	static AUTH_DAT adat = { 0 };
	83	#if defined(ENCRYPT)
	84	static Block session_key = { 0 };
	85	#endif
b7c8f459 DB	86	static Schedule sched;
b7c8f459 DB	87	static Block challange = { 0 };
54b7f482 DB	88
54b7f482 DB	89	static int
b7c8f459 DB	90	Data(ap, type, d, c)
b7c8f459 DB	91	Authenticator *ap;
54b7f482 DB	92	int type;
	93	void *d;
	94	int c;
	95	{
b7c8f459	96	unsigned char *p = str_data + 4;
54b7f482 DB	97	unsigned char cd = (unsigned char )d;
	98
	99	if (c == -1)
	100	c = strlen((char *)cd);
	101
	102	if (auth_debug_mode) {
	103	printf("%s:%d: [%d] (%d)",
	104	str_data[3] == TELQUAL_IS ? ">>>IS" : ">>>REPLY",
	105	str_data[3],
	106	type, c);
	107	printd(d, c);
	108	printf("\r\n");
	109	}
b7c8f459 DB	110	*p++ = ap->type;
b7c8f459 DB	111	*p++ = ap->way;
54b7f482 DB	112	*p++ = type;
	113	while (c-- > 0) {
	114	if ((p++ = cd++) == IAC)
	115	*p++ = IAC;
	116	}
	117	*p++ = IAC;
	118	*p++ = SE;
	119	if (str_data[3] == TELQUAL_IS)
	120	printsub('>', &str_data[2], p - (&str_data[2]));
	121	return(net_write(str_data, p - str_data));
	122	}
	123
	124	int
	125	kerberos4_init(ap, server)
	126	Authenticator *ap;
	127	int server;
	128	{
	129	if (server)
	130	str_data[3] = TELQUAL_REPLY;
	131	else
	132	str_data[3] = TELQUAL_IS;
54b7f482 DB	133	return(1);
	134	}
	135
	136	char dst_realm_buf[REALM_SZ], *dest_realm = NULL;
	137	int dst_realm_sz = REALM_SZ;
	138
	139	int
	140	kerberos4_send(ap)
	141	Authenticator *ap;
	142	{
	143	KTEXT_ST auth;
	144	Block enckey;
	145	char instance[INST_SZ];
	146	char *realm;
	147	char *krb_realmofhost();
	148	char *krb_get_phost();
	149	CREDENTIALS cred;
54b7f482 DB	150	int r;
	151
	152	if (!UserNameRequested) {
	153	if (auth_debug_mode) {
	154	printf("Kerberos V4: no user name supplied\r\n");
	155	}
	156	return(0);
	157	}
	158
	159	bzero(instance, sizeof(instance));
	160	if (realm = krb_get_phost(RemoteHostName))
	161	strncpy(instance, realm, sizeof(instance));
	162	instance[sizeof(instance)-1] = '\0';
	163
	164	realm = dest_realm ? dest_realm : krb_realmofhost(RemoteHostName);
	165	if (!realm) {
	166	if (auth_debug_mode) {
	167	printf("Kerberos V4: no realm for %s\r\n", RemoteHostName);
	168	}
	169	return(0);
	170	}
	171	if (r = krb_mk_req(&auth, "rcmd", instance, realm, 0L)) {
	172	if (auth_debug_mode) {
	173	printf("mk_req failed: %s\r\n", krb_err_txt[r]);
	174	}
	175	return(0);
	176	}
	177	if (r = krb_get_cred("rcmd", instance, realm, &cred)) {
	178	if (auth_debug_mode) {
	179	printf("get_cred failed: %s\r\n", krb_err_txt[r]);
	180	}
	181	return(0);
	182	}
b7c8f459	183	if (!auth_sendname(UserNameRequested, strlen(UserNameRequested))) {
54b7f482 DB	184	if (auth_debug_mode)
	185	printf("Not enough room for user name\r\n");
	186	return(0);
	187	}
	188	if (auth_debug_mode)
	189	printf("Sent %d bytes of authentication data\r\n", auth.length);
b7c8f459	190	if (!Data(ap, KRB_AUTH, (void *)auth.dat, auth.length)) {
54b7f482 DB	191	if (auth_debug_mode)
	192	printf("Not enough room for authentication data\r\n");
	193	return(0);
	194	}
b7c8f459 DB	195	/*
	196	* If we are doing mutual authentication, get set up to send
	197	* the challange, and verify it when the response comes back.
	198	*/
	199	if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL) {
	200	register int i;
	201
	202	des_key_sched(cred.session, sched);
	203	des_set_random_generator_seed(cred.session);
	204	des_new_random_key(challange);
	205	des_ecb_encrypt(challange, session_key, sched, 1);
	206	/*
	207	* Increment the challange by 1, and encrypt it for
	208	* later comparison.
	209	*/
	210	for (i = 7; i >= 0; --i) {
	211	register int x;
	212	x = (unsigned int)challange[i] + 1;
	213	challange[i] = x; /* ignore overflow */
	214	if (x < 256) /* if no overflow, all done */
	215	break;
	216	}
	217	des_ecb_encrypt(challange, challange, sched, 1);
	218	}
54b7f482 DB	219
	220	if (auth_debug_mode) {
	221	printf("CK: %d:", cksum(auth.dat, auth.length));
	222	printd(auth.dat, auth.length);
	223	printf("\r\n");
	224	printf("Sent Kerberos V4 credentials to server\r\n");
	225	}
	226	return(1);
	227	}
	228
	229	void
	230	kerberos4_is(ap, data, cnt)
	231	Authenticator *ap;
	232	unsigned char *data;
	233	int cnt;
	234	{
	235	Session_Key skey;
	236	Block datablock;
	237	char realm[REALM_SZ];
	238	char instance[INST_SZ];
54b7f482 DB	239	int r;
	240
	241	if (cnt-- < 1)
	242	return;
	243	switch (*data++) {
54b7f482 DB	244	case KRB_AUTH:
54b7f482 DB	245	if (krb_get_lrealm(realm, 1) != KSUCCESS) {
b7c8f459	246	Data(ap, KRB_REJECT, (void *)"No local V4 Realm.", -1);
54b7f482 DB	247	auth_finished(ap, AUTH_REJECT);
	248	if (auth_debug_mode)
	249	printf("No local realm\r\n");
	250	return;
	251	}
	252	bcopy((void )data, (void )auth.dat, auth.length = cnt);
	253	if (auth_debug_mode) {
	254	printf("Got %d bytes of authentication data\r\n", cnt);
	255	printf("CK: %d:", cksum(auth.dat, auth.length));
	256	printd(auth.dat, auth.length);
	257	printf("\r\n");
	258	}
	259	instance[0] = '*'; instance[1] = 0;
	260	if (r = krb_rd_req(&auth, "rcmd", instance, 0, &adat, "")) {
	261	if (auth_debug_mode)
	262	printf("Kerberos failed him as %s\r\n", name);
b7c8f459	263	Data(ap, KRB_REJECT, (void *)krb_err_txt[r], -1);
54b7f482 DB	264	auth_finished(ap, AUTH_REJECT);
	265	return;
	266	}
	267	bcopy((void )adat.session, (void )session_key, sizeof(Block));
	268	krb_kntoln(&adat, name);
b7c8f459	269	Data(ap, KRB_ACCEPT, (void *)0, 0);
54b7f482 DB	270	auth_finished(ap, AUTH_USER);
	271	if (auth_debug_mode) {
	272	printf("Kerberos accepting him as %s\r\n", name);
	273	}
b7c8f459 DB	274	break;
	275
	276	case KRB_CHALLANGE:
	277	if (!VALIDKEY(session_key)) {
	278	/*
	279	* We don't have a valid session key, so just
	280	* send back a response with an empty session
	281	* key.
	282	*/
	283	Data(ap, KRB_RESPONSE, (void *)0, 0);
	284	break;
54b7f482	285	}
b7c8f459 DB	286
	287	des_key_sched(session_key, sched);
	288	bcopy((void )data, (void )datablock, sizeof(Block));
	289	/*
	290	* Take the received encrypted challange, and encrypt
	291	* it again to get a unique session_key for the
	292	* ENCRYPT option.
	293	*/
	294	des_ecb_encrypt(datablock, session_key, sched, 1);
	295	skey.type = SK_DES;
	296	skey.length = 8;
	297	skey.data = session_key;
	298	encrypt_session_key(&skey, 1);
	299	/*
	300	* Now decrypt the received encrypted challange,
	301	* increment by one, re-encrypt it and send it back.
	302	*/
	303	des_ecb_encrypt(datablock, challange, sched, 0);
	304	for (r = 7; r >= 0; r++) {
	305	register int t;
	306	t = (unsigned int)challange[r] + 1;
	307	challange[r] = t; /* ignore overflow */
	308	if (t < 256) /* if no overflow, all done */
	309	break;
	310	}
	311	des_ecb_encrypt(challange, challange, sched, 1);
	312	Data(ap, KRB_RESPONSE, (void *)challange, sizeof(challange));
	313	break;
	314
54b7f482 DB	315	default:
	316	if (auth_debug_mode)
	317	printf("Unknown Kerberos option %d\r\n", data[-1]);
b7c8f459 DB	318	Data(ap, KRB_REJECT, 0, 0);
b7c8f459 DB	319	break;
54b7f482 DB	320	}
	321	}
	322
	323	void
	324	kerberos4_reply(ap, data, cnt)
	325	Authenticator *ap;
	326	unsigned char *data;
	327	int cnt;
	328	{
	329	Session_Key skey;
	330
	331	if (cnt-- < 1)
	332	return;
	333	switch (*data++) {
	334	case KRB_REJECT:
	335	if (cnt > 0) {
	336	printf("[ Kerberos V4 refuses authentication because %.*s ]\r\n",
	337	cnt, data);
	338	} else
	339	printf("[ Kerberos V4 refuses authentication ]\r\n");
	340	auth_send_retry();
	341	return;
	342	case KRB_ACCEPT:
b7c8f459 DB	343	printf("[ Kerberos V4 accepts you ]\n");
	344	if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL) {
	345	/*
	346	* Send over the encrypted challange.
	347	*/
	348	Data(ap, KRB_CHALLANGE, (void *)session_key,
	349	sizeof(session_key));
54b7f482	350	#if defined(ENCRYPT)
b7c8f459 DB	351	des_ecb_encrypt(session_key, session_key, sched, 1);
	352	skey.type = SK_DES;
	353	skey.length = 8;
	354	skey.data = session_key;
	355	encrypt_session_key(&skey, 0);
54b7f482	356	#endif
b7c8f459 DB	357	return;
b7c8f459 DB	358	}
54b7f482 DB	359	auth_finished(ap, AUTH_USER);
54b7f482 DB	360	return;
b7c8f459 DB	361	case KRB_RESPONSE:
	362	/*
	363	* Verify that the response to the challange is correct.
	364	*/
	365	if ((cnt != sizeof(Block)) \|\|
	366	(0 != memcmp((void )data, (void )challange,
	367	sizeof(challange))))
	368	{
	369	printf("[ Kerberos V4 challange failed!!! ]\r\n");
	370	auth_send_retry();
	371	return;
	372	}
	373	printf("[ Kerberos V4 challange successful ]\r\n");
	374	auth_finished(ap, AUTH_USER);
	375	break;
54b7f482 DB	376	default:
	377	if (auth_debug_mode)
	378	printf("Unknown Kerberos option %d\r\n", data[-1]);
	379	return;
	380	}
	381	}
	382
	383	int
	384	kerberos4_status(ap, name, level)
	385	Authenticator *ap;
	386	char *name;
	387	int level;
	388	{
	389	if (level < AUTH_USER)
	390	return(level);
	391
	392	if (UserNameRequested && !kuserok(&adat, UserNameRequested)) {
	393	strcpy(name, UserNameRequested);
	394	return(AUTH_VALID);
	395	} else
	396	return(AUTH_USER);
	397	}
	398
	399	#define BUMP(buf, len) while (*(buf)) {++(buf), --(len);}
	400	#define ADDC(buf, len, c) if ((len) > 0) {*(buf)++ = (c); --(len);}
	401
	402	void
	403	kerberos4_printsub(data, cnt, buf, buflen)
	404	unsigned char data, buf;
	405	int cnt, buflen;
	406	{
	407	char lbuf[32];
	408	register int i;
	409
	410	buf[buflen-1] = '\0'; /* make sure its NULL terminated */
	411	buflen -= 1;
	412
	413	switch(data[3]) {
54b7f482 DB	414	case KRB_REJECT: /* Rejected (reason might follow) */
	415	strncpy((char *)buf, " REJECT ", buflen);
	416	goto common;
	417
	418	case KRB_ACCEPT: /* Accepted (name might follow) */
	419	strncpy((char *)buf, " ACCEPT ", buflen);
	420	common:
	421	BUMP(buf, buflen);
	422	if (cnt <= 4)
	423	break;
	424	ADDC(buf, buflen, '"');
	425	for (i = 4; i < cnt; i++)
	426	ADDC(buf, buflen, data[i]);
	427	ADDC(buf, buflen, '"');
	428	ADDC(buf, buflen, '\0');
	429	break;
	430
	431	case KRB_AUTH: /* Authentication data follows */
	432	strncpy((char *)buf, " AUTH", buflen);
	433	goto common2;
	434
b7c8f459 DB	435	case KRB_CHALLANGE:
	436	strncpy((char *)buf, " CHALLANGE", buflen);
	437	goto common2;
	438
	439	case KRB_RESPONSE:
	440	strncpy((char *)buf, " RESPONSE", buflen);
54b7f482 DB	441	goto common2;
	442
	443	default:
	444	sprintf(lbuf, " %d (unknown)", data[3]);
	445	strncpy((char *)buf, lbuf, buflen);
	446	common2:
	447	BUMP(buf, buflen);
	448	for (i = 4; i < cnt; i++) {
	449	sprintf(lbuf, " %d", data[i]);
	450	strncpy((char *)buf, lbuf, buflen);
	451	BUMP(buf, buflen);
	452	}
	453	break;
	454	}
	455	}
	456
	457	int
	458	cksum(d, n)
	459	unsigned char *d;
	460	int n;
	461	{
	462	int ck = 0;
	463
	464	switch (n&03)
	465	while (n > 0) {
	466	case 0:
	467	ck ^= *d++ << 24;
	468	--n;
	469	case 3:
	470	ck ^= *d++ << 16;
	471	--n;
	472	case 2:
	473	ck ^= *d++ << 8;
	474	--n;
	475	case 1:
	476	ck ^= *d++;
	477	--n;
	478	}
	479	return(ck);
	480	}
	481	#endif
	482
	483	#ifdef notdef
	484
	485	prkey(msg, key)
	486	char *msg;
	487	unsigned char *key;
	488	{
	489	register int i;
	490	printf("%s:", msg);
	491	for (i = 0; i < 8; i++)
	492	printf(" %3d", key[i]);
	493	printf("\r\n");
	494	}
	495	#endif