usr/src/lib/libtelnet/kerberos.c

/*-
 * Copyright (c) 1991, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
static char sccsid[] = "@(#)kerberos.c  8.1 (Berkeley) 6/4/93";
#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>
#include <des.h>        /* BSD wont include this in krb.h, so we do it here */
#include <krb.h>
#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 kerberos4_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_CHALLENGE   3               /* Challenge for mutual auth. */
#define KRB_RESPONSE    4               /* Response for mutual auth. */

#define KRB_SERVICE_NAME   "rcmd"

static  KTEXT_ST auth;
static  char name[ANAME_SZ];
static  AUTH_DAT adat = { 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;
{
        FILE *fp;

        if (server) {
                str_data[3] = TELQUAL_REPLY;
                if ((fp = fopen(KEYFILE, "r")) == NULL)
                        return(0);
                fclose(fp);
        } 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;
        char instance[INST_SZ];
        char *realm;
        char *krb_realmofhost();
        char *krb_get_phost();
        CREDENTIALS cred;
        int r;

        printf("[ Trying KERBEROS4 ... ]\n");
        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) {
                printf("Kerberos V4: no realm for %s\r\n", RemoteHostName);
                return(0);
        }
        if (r = krb_mk_req(&auth, KRB_SERVICE_NAME, instance, realm, 0L)) {
                printf("mk_req failed: %s\r\n", krb_err_txt[r]);
                return(0);
        }
        if (r = krb_get_cred(KRB_SERVICE_NAME, instance, realm, &cred)) {
                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 (auth_debug_mode) {
                printf("CK: %d:", kerberos4_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;
{
        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:", kerberos4_cksum(auth.dat, auth.length));
                        printd(auth.dat, auth.length);
                        printf("\r\n");
                }
                instance[0] = '*'; instance[1] = 0;
                if (r = krb_rd_req(&auth, KRB_SERVICE_NAME,
                                   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;
                }
                krb_kntoln(&adat, name);

                if (UserNameRequested && !kuserok(&adat, UserNameRequested))
                        Data(ap, KRB_ACCEPT, (void *)0, 0);
                else
                        Data(ap, KRB_REJECT,
                                (void *)"user is not authorized", -1);
                auth_finished(ap, AUTH_USER);
                break;

        case KRB_CHALLENGE:
                Data(ap, KRB_RESPONSE, (void *)0, 0);
                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;
{

        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 challenge.
                         */
                        Data(ap, KRB_CHALLENGE, (void *)0, 0);
                        return;
                }
                auth_finished(ap, AUTH_USER);
                return;
        case KRB_RESPONSE:
                        printf("[ Kerberos V4 challenge failed!!! ]\r\n");
                        auth_send_retry();
                        return;
                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_CHALLENGE:
                strncpy((char *)buf, " CHALLENGE", 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
kerberos4_cksum(d, n)
        unsigned char *d;
        int n;
{
        int ck = 0;

        /*
         * A comment is probably needed here for those not
         * well versed in the "C" language.  Yes, this is
         * supposed to be a "switch" with the body of the
         * "switch" being a "while" statement.  The whole
         * purpose of the switch is to allow us to jump into
         * the middle of the while() loop, and then not have
         * to do any more switch()s.
         *
         * Some compilers will spit out a warning message
         * about the loop not being entered at the top.
         */
        switch (n&03)
        while (n > 0) {
        case 0:
                ck ^= (int)*d++ << 24;
                --n;
        case 3:
                ck ^= (int)*d++ << 16;
                --n;
        case 2:
                ck ^= (int)*d++ << 8;
                --n;
        case 1:
                ck ^= (int)*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