555 lines
14 KiB
C
555 lines
14 KiB
C
/*-
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the University of
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* California, Berkeley and its contributors.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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static char sccsid[] = "@(#)kerberos.c 8.1 (Berkeley) 6/4/93";
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#endif /* not lint */
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/*
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* Copyright (C) 1990 by the Massachusetts Institute of Technology
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*
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* Export of this software from the United States of America is assumed
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* to require a specific license from the United States Government.
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* It is the responsibility of any person or organization contemplating
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* export to obtain such a license before exporting.
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*
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* WITHIN THAT CONSTRAINT, permission to use, copy, modify, and
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* distribute this software and its documentation for any purpose and
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* without fee is hereby granted, provided that the above copyright
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* notice appear in all copies and that both that copyright notice and
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* this permission notice appear in supporting documentation, and that
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* the name of M.I.T. not be used in advertising or publicity pertaining
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* to distribution of the software without specific, written prior
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* permission. M.I.T. makes no representations about the suitability of
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* this software for any purpose. It is provided "as is" without express
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* or implied warranty.
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*/
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#ifdef KRB4
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#include <sys/types.h>
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#include <arpa/telnet.h>
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#include <stdio.h>
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#include <des.h> /* BSD wont include this in krb.h, so we do it here */
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#include <krb.h>
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#ifdef __STDC__
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#include <stdlib.h>
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#endif
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#ifdef NO_STRING_H
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#include <strings.h>
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#else
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#include <string.h>
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#endif
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#include "encrypt.h"
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#include "auth.h"
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#include "misc.h"
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int kerberos4_cksum P((unsigned char *, int));
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int krb_mk_req P((KTEXT, char *, char *, char *, u_long));
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int krb_rd_req P((KTEXT, char *, char *, u_long, AUTH_DAT *, char *));
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int krb_kntoln P((AUTH_DAT *, char *));
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int krb_get_cred P((char *, char *, char *, CREDENTIALS *));
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int krb_get_lrealm P((char *, int));
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int kuserok P((AUTH_DAT *, char *));
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extern auth_debug_mode;
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static unsigned char str_data[1024] = { IAC, SB, TELOPT_AUTHENTICATION, 0,
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AUTHTYPE_KERBEROS_V4, };
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static unsigned char str_name[1024] = { IAC, SB, TELOPT_AUTHENTICATION,
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TELQUAL_NAME, };
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#define KRB_AUTH 0 /* Authentication data follows */
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#define KRB_REJECT 1 /* Rejected (reason might follow) */
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#define KRB_ACCEPT 2 /* Accepted */
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#define KRB_CHALLENGE 3 /* Challenge for mutual auth. */
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#define KRB_RESPONSE 4 /* Response for mutual auth. */
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#define KRB_SERVICE_NAME "rcmd"
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static KTEXT_ST auth;
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static char name[ANAME_SZ];
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static AUTH_DAT adat = { 0 };
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#ifdef ENCRYPTION
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static Block session_key = { 0 };
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static Schedule sched;
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static Block challenge = { 0 };
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#endif /* ENCRYPTION */
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static int
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Data(ap, type, d, c)
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Authenticator *ap;
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int type;
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void *d;
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int c;
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{
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unsigned char *p = str_data + 4;
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unsigned char *cd = (unsigned char *)d;
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if (c == -1)
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c = strlen((char *)cd);
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if (auth_debug_mode) {
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printf("%s:%d: [%d] (%d)",
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str_data[3] == TELQUAL_IS ? ">>>IS" : ">>>REPLY",
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str_data[3],
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type, c);
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printd(d, c);
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printf("\r\n");
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}
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*p++ = ap->type;
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*p++ = ap->way;
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*p++ = type;
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while (c-- > 0) {
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if ((*p++ = *cd++) == IAC)
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*p++ = IAC;
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}
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*p++ = IAC;
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*p++ = SE;
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if (str_data[3] == TELQUAL_IS)
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printsub('>', &str_data[2], p - (&str_data[2]));
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return(net_write(str_data, p - str_data));
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}
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int
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kerberos4_init(ap, server)
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Authenticator *ap;
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int server;
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{
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FILE *fp;
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if (server) {
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str_data[3] = TELQUAL_REPLY;
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if ((fp = fopen(KEYFILE, "r")) == NULL)
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return(0);
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fclose(fp);
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} else {
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str_data[3] = TELQUAL_IS;
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}
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return(1);
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}
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char dst_realm_buf[REALM_SZ], *dest_realm = NULL;
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int dst_realm_sz = REALM_SZ;
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int
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kerberos4_send(ap)
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Authenticator *ap;
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{
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KTEXT_ST auth;
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#ifdef ENCRYPTION
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Block enckey;
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#endif /* ENCRYPTION */
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char instance[INST_SZ];
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char *realm;
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char *krb_realmofhost();
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char *krb_get_phost();
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CREDENTIALS cred;
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int r;
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printf("[ Trying KERBEROS4 ... ]\n");
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if (!UserNameRequested) {
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if (auth_debug_mode) {
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printf("Kerberos V4: no user name supplied\r\n");
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}
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return(0);
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}
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bzero(instance, sizeof(instance));
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if (realm = krb_get_phost(RemoteHostName))
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strncpy(instance, realm, sizeof(instance));
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instance[sizeof(instance)-1] = '\0';
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realm = dest_realm ? dest_realm : krb_realmofhost(RemoteHostName);
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if (!realm) {
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printf("Kerberos V4: no realm for %s\r\n", RemoteHostName);
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return(0);
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}
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if (r = krb_mk_req(&auth, KRB_SERVICE_NAME, instance, realm, 0L)) {
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printf("mk_req failed: %s\r\n", krb_err_txt[r]);
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return(0);
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}
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if (r = krb_get_cred(KRB_SERVICE_NAME, instance, realm, &cred)) {
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printf("get_cred failed: %s\r\n", krb_err_txt[r]);
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return(0);
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}
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if (!auth_sendname(UserNameRequested, strlen(UserNameRequested))) {
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if (auth_debug_mode)
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printf("Not enough room for user name\r\n");
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return(0);
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}
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if (auth_debug_mode)
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printf("Sent %d bytes of authentication data\r\n", auth.length);
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if (!Data(ap, KRB_AUTH, (void *)auth.dat, auth.length)) {
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if (auth_debug_mode)
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printf("Not enough room for authentication data\r\n");
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return(0);
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}
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#ifdef ENCRYPTION
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/*
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* If we are doing mutual authentication, get set up to send
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* the challenge, and verify it when the response comes back.
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*/
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if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL) {
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register int i;
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des_key_sched(cred.session, sched);
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des_set_random_generator_seed(cred.session);
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des_new_random_key(challenge);
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des_ecb_encrypt(challenge, session_key, sched, 1);
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/*
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* Increment the challenge by 1, and encrypt it for
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* later comparison.
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*/
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for (i = 7; i >= 0; --i) {
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register int x;
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x = (unsigned int)challenge[i] + 1;
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challenge[i] = x; /* ignore overflow */
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if (x < 256) /* if no overflow, all done */
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break;
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}
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des_ecb_encrypt(challenge, challenge, sched, 1);
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}
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#endif /* ENCRYPTION */
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if (auth_debug_mode) {
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printf("CK: %d:", kerberos4_cksum(auth.dat, auth.length));
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printd(auth.dat, auth.length);
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printf("\r\n");
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printf("Sent Kerberos V4 credentials to server\r\n");
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}
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return(1);
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}
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void
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kerberos4_is(ap, data, cnt)
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Authenticator *ap;
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unsigned char *data;
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int cnt;
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{
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#ifdef ENCRYPTION
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Session_Key skey;
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Block datablock;
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#endif /* ENCRYPTION */
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char realm[REALM_SZ];
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char instance[INST_SZ];
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int r;
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if (cnt-- < 1)
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return;
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switch (*data++) {
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case KRB_AUTH:
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if (krb_get_lrealm(realm, 1) != KSUCCESS) {
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Data(ap, KRB_REJECT, (void *)"No local V4 Realm.", -1);
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auth_finished(ap, AUTH_REJECT);
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if (auth_debug_mode)
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printf("No local realm\r\n");
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return;
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}
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bcopy((void *)data, (void *)auth.dat, auth.length = cnt);
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if (auth_debug_mode) {
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printf("Got %d bytes of authentication data\r\n", cnt);
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printf("CK: %d:", kerberos4_cksum(auth.dat, auth.length));
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printd(auth.dat, auth.length);
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printf("\r\n");
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}
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instance[0] = '*'; instance[1] = 0;
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if (r = krb_rd_req(&auth, KRB_SERVICE_NAME,
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instance, 0, &adat, "")) {
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if (auth_debug_mode)
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printf("Kerberos failed him as %s\r\n", name);
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Data(ap, KRB_REJECT, (void *)krb_err_txt[r], -1);
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auth_finished(ap, AUTH_REJECT);
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return;
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}
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#ifdef ENCRYPTION
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bcopy((void *)adat.session, (void *)session_key, sizeof(Block));
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#endif /* ENCRYPTION */
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krb_kntoln(&adat, name);
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if (UserNameRequested && !kuserok(&adat, UserNameRequested))
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Data(ap, KRB_ACCEPT, (void *)0, 0);
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else
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Data(ap, KRB_REJECT,
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(void *)"user is not authorized", -1);
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auth_finished(ap, AUTH_USER);
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break;
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case KRB_CHALLENGE:
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#ifndef ENCRYPTION
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Data(ap, KRB_RESPONSE, (void *)0, 0);
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#else /* ENCRYPTION */
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if (!VALIDKEY(session_key)) {
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/*
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* We don't have a valid session key, so just
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* send back a response with an empty session
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* key.
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*/
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Data(ap, KRB_RESPONSE, (void *)0, 0);
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break;
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}
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des_key_sched(session_key, sched);
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bcopy((void *)data, (void *)datablock, sizeof(Block));
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/*
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* Take the received encrypted challenge, and encrypt
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* it again to get a unique session_key for the
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* ENCRYPT option.
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*/
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des_ecb_encrypt(datablock, session_key, sched, 1);
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skey.type = SK_DES;
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skey.length = 8;
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skey.data = session_key;
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encrypt_session_key(&skey, 1);
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/*
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* Now decrypt the received encrypted challenge,
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* increment by one, re-encrypt it and send it back.
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*/
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des_ecb_encrypt(datablock, challenge, sched, 0);
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for (r = 7; r >= 0; r++) {
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register int t;
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t = (unsigned int)challenge[r] + 1;
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challenge[r] = t; /* ignore overflow */
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if (t < 256) /* if no overflow, all done */
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break;
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}
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des_ecb_encrypt(challenge, challenge, sched, 1);
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Data(ap, KRB_RESPONSE, (void *)challenge, sizeof(challenge));
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#endif /* ENCRYPTION */
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break;
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default:
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if (auth_debug_mode)
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printf("Unknown Kerberos option %d\r\n", data[-1]);
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Data(ap, KRB_REJECT, 0, 0);
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break;
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}
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}
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void
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kerberos4_reply(ap, data, cnt)
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Authenticator *ap;
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unsigned char *data;
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int cnt;
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{
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#ifdef ENCRYPTION
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Session_Key skey;
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#endif /* ENCRYPTION */
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if (cnt-- < 1)
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return;
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switch (*data++) {
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case KRB_REJECT:
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if (cnt > 0) {
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printf("[ Kerberos V4 refuses authentication because %.*s ]\r\n",
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cnt, data);
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} else
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printf("[ Kerberos V4 refuses authentication ]\r\n");
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auth_send_retry();
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return;
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case KRB_ACCEPT:
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printf("[ Kerberos V4 accepts you ]\n");
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if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL) {
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/*
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* Send over the encrypted challenge.
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*/
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#ifndef ENCRYPTION
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Data(ap, KRB_CHALLENGE, (void *)0, 0);
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#else /* ENCRYPTION */
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Data(ap, KRB_CHALLENGE, (void *)session_key,
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sizeof(session_key));
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des_ecb_encrypt(session_key, session_key, sched, 1);
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skey.type = SK_DES;
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skey.length = 8;
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skey.data = session_key;
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encrypt_session_key(&skey, 0);
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#endif /* ENCRYPTION */
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return;
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}
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auth_finished(ap, AUTH_USER);
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return;
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case KRB_RESPONSE:
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#ifdef ENCRYPTION
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/*
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* Verify that the response to the challenge is correct.
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*/
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if ((cnt != sizeof(Block)) ||
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(0 != memcmp((void *)data, (void *)challenge,
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sizeof(challenge))))
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{
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#endif /* ENCRYPTION */
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printf("[ Kerberos V4 challenge failed!!! ]\r\n");
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auth_send_retry();
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return;
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#ifdef ENCRYPTION
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}
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printf("[ Kerberos V4 challenge successful ]\r\n");
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auth_finished(ap, AUTH_USER);
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#endif /* ENCRYPTION */
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break;
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default:
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if (auth_debug_mode)
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printf("Unknown Kerberos option %d\r\n", data[-1]);
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return;
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}
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}
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int
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kerberos4_status(ap, name, level)
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Authenticator *ap;
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char *name;
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int level;
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{
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if (level < AUTH_USER)
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return(level);
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if (UserNameRequested && !kuserok(&adat, UserNameRequested)) {
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strcpy(name, UserNameRequested);
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return(AUTH_VALID);
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} else
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return(AUTH_USER);
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}
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#define BUMP(buf, len) while (*(buf)) {++(buf), --(len);}
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#define ADDC(buf, len, c) if ((len) > 0) {*(buf)++ = (c); --(len);}
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void
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kerberos4_printsub(data, cnt, buf, buflen)
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unsigned char *data, *buf;
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int cnt, buflen;
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{
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char lbuf[32];
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register int i;
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buf[buflen-1] = '\0'; /* make sure its NULL terminated */
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buflen -= 1;
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switch(data[3]) {
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case KRB_REJECT: /* Rejected (reason might follow) */
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strncpy((char *)buf, " REJECT ", buflen);
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goto common;
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case KRB_ACCEPT: /* Accepted (name might follow) */
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strncpy((char *)buf, " ACCEPT ", buflen);
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common:
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BUMP(buf, buflen);
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if (cnt <= 4)
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break;
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ADDC(buf, buflen, '"');
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for (i = 4; i < cnt; i++)
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ADDC(buf, buflen, data[i]);
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ADDC(buf, buflen, '"');
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ADDC(buf, buflen, '\0');
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break;
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case KRB_AUTH: /* Authentication data follows */
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strncpy((char *)buf, " AUTH", buflen);
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goto common2;
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case KRB_CHALLENGE:
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strncpy((char *)buf, " CHALLENGE", buflen);
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goto common2;
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case KRB_RESPONSE:
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strncpy((char *)buf, " RESPONSE", buflen);
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goto common2;
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default:
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sprintf(lbuf, " %d (unknown)", data[3]);
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strncpy((char *)buf, lbuf, buflen);
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common2:
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BUMP(buf, buflen);
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for (i = 4; i < cnt; i++) {
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sprintf(lbuf, " %d", data[i]);
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strncpy((char *)buf, lbuf, buflen);
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BUMP(buf, buflen);
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}
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break;
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}
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}
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int
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kerberos4_cksum(d, n)
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unsigned char *d;
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int n;
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{
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int ck = 0;
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/*
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* A comment is probably needed here for those not
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* well versed in the "C" language. Yes, this is
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* supposed to be a "switch" with the body of the
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* "switch" being a "while" statement. The whole
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* purpose of the switch is to allow us to jump into
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* the middle of the while() loop, and then not have
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* to do any more switch()s.
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*
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* Some compilers will spit out a warning message
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* about the loop not being entered at the top.
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*/
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switch (n&03)
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while (n > 0) {
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case 0:
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ck ^= (int)*d++ << 24;
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|
--n;
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case 3:
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|
ck ^= (int)*d++ << 16;
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|
--n;
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|
case 2:
|
|
ck ^= (int)*d++ << 8;
|
|
--n;
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|
case 1:
|
|
ck ^= (int)*d++;
|
|
--n;
|
|
}
|
|
return(ck);
|
|
}
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|
#endif
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|
|
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#ifdef notdef
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|
|
|
prkey(msg, key)
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|
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
|