581 lines
15 KiB
C
581 lines
15 KiB
C
/*-
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* Copyright (c) 1991 The Regents of the University of California.
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* 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[] = "from: @(#)kerberos5.c 5.2 (Berkeley) 3/22/91";*/
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static char rcsid[] = "$Id: kerberos5.c,v 1.2 1993/08/01 18:32:34 mycroft Exp $";
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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 KRB5
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#include <arpa/telnet.h>
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#include <stdio.h>
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#include <krb5/krb5.h>
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#include <krb5/crc-32.h>
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#include <krb5/libos-proto.h>
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#include <netdb.h>
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#include <ctype.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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extern auth_debug_mode;
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char *malloc();
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static unsigned char str_data[1024] = { IAC, SB, TELOPT_AUTHENTICATION, 0,
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AUTHTYPE_KERBEROS_V5, };
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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_CHALLANGE 3 /* Challange for mutual auth. */
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#define KRB_RESPONSE 4 /* Response for mutual auth. */
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static krb5_data auth;
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/* telnetd gets session key from here */
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static krb5_tkt_authent *authdat = NULL;
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#if defined(ENCRYPT)
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Block session_key;
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#endif
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static Schedule sched;
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static Block challange;
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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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kerberos5_init(ap, server)
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Authenticator *ap;
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int server;
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{
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if (server)
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str_data[3] = TELQUAL_REPLY;
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else
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str_data[3] = TELQUAL_IS;
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krb5_init_ets();
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return(1);
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}
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int
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kerberos5_send(ap)
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Authenticator *ap;
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{
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char **realms;
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char *name;
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char *p1, *p2;
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krb5_checksum ksum;
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krb5_octet sum[CRC32_CKSUM_LENGTH];
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krb5_data *server[4];
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krb5_data srvdata[3];
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krb5_error_code r;
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krb5_ccache ccache;
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krb5_creds creds; /* telnet gets session key from here */
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extern krb5_flags krb5_kdc_default_options;
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ksum.checksum_type = CKSUMTYPE_CRC32;
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ksum.contents = sum;
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ksum.length = sizeof(sum);
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bzero((void *)sum, sizeof(sum));
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if (!UserNameRequested) {
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if (auth_debug_mode) {
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printf("Kerberos V5: no user name supplied\r\n");
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}
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return(0);
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}
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if (r = krb5_cc_default(&ccache)) {
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if (auth_debug_mode) {
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printf("Kerberos V5: could not get default ccache\r\n");
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}
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return(0);
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}
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if ((name = malloc(strlen(RemoteHostName)+1)) == NULL) {
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if (auth_debug_mode)
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printf("Out of memory for hostname in Kerberos V5\r\n");
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return(0);
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}
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if (r = krb5_get_host_realm(RemoteHostName, &realms)) {
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if (auth_debug_mode)
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printf("Kerberos V5: no realm for %s\r\n", RemoteHostName);
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free(name);
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return(0);
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}
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p1 = RemoteHostName;
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p2 = name;
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while (*p2 = *p1++) {
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if (isupper(*p2))
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*p2 |= 040;
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++p2;
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}
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srvdata[0].data = realms[0];
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srvdata[0].length = strlen(realms[0]);
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srvdata[1].data = "rcmd";
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srvdata[1].length = 4;
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srvdata[2].data = name;
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srvdata[2].length = p2 - name;
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server[0] = &srvdata[0];
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server[1] = &srvdata[1];
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server[2] = &srvdata[2];
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server[3] = 0;
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bzero((char *)&creds, sizeof(creds));
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creds.server = (krb5_principal)server;
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if (r = krb5_cc_get_principal(ccache, &creds.client)) {
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if (auth_debug_mode) {
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printf("Keberos V5: failure on principal (%d)\r\n",
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error_message(r));
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}
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free(name);
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krb5_free_host_realm(realms);
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return(0);
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}
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if (r = krb5_get_credentials(krb5_kdc_default_options, ccache, &creds)) {
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if (auth_debug_mode) {
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printf("Keberos V5: failure on credentials(%d)\r\n",r);
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}
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free(name);
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krb5_free_host_realm(realms);
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return(0);
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}
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r = krb5_mk_req_extended(0, &ksum, &creds.times,
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krb5_kdc_default_options,
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ccache, &creds, 0, &auth);
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free(name);
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krb5_free_host_realm(realms);
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if (r) {
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if (auth_debug_mode) {
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printf("Keberos V5: mk_req failed\r\n");
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}
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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 (!Data(ap, KRB_AUTH, auth.data, 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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/*
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* If we are doing mutual authentication, get set up to send
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* the challange, 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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&& (creds.keyblock.keytype == KEYTYPE_DES)) {
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register int i;
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des_key_sched(creds.keyblock.contents, sched);
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des_set_random_generator_seed(creds.keyblock.contents);
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des_new_random_key(challange);
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des_ecb_encrypt(challange, session_key, sched, 1);
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/*
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* Increment the challange 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)challange[i] + 1;
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challange[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(challange, challange, sched, 1);
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}
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if (auth_debug_mode) {
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printf("Sent Kerberos V5 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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kerberos5_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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int r;
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struct hostent *hp;
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char *p1, *p2;
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static char *realm = NULL;
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krb5_data *server[4];
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krb5_data srvdata[3];
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Session_Key skey;
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char *name;
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char *getenv();
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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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auth.data = (char *)data;
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auth.length = cnt;
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if (!(hp = gethostbyname(LocalHostName))) {
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if (auth_debug_mode)
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printf("Cannot resolve local host name\r\n");
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Data(ap, KRB_REJECT, "Unknown local hostname.", -1);
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auth_finished(ap, AUTH_REJECT);
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return;
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}
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if (!realm && (krb5_get_default_realm(&realm))) {
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if (auth_debug_mode)
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printf("Could not get defualt realm\r\n");
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Data(ap, KRB_REJECT, "Could not get default realm.", -1);
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auth_finished(ap, AUTH_REJECT);
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return;
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}
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if ((name = malloc(strlen(hp->h_name)+1)) == NULL) {
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if (auth_debug_mode)
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printf("Out of memory for hostname in Kerberos V5\r\n");
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Data(ap, KRB_REJECT, "Out of memory.", -1);
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auth_finished(ap, AUTH_REJECT);
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return;
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}
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p1 = hp->h_name;
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p2 = name;
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while (*p2 = *p1++) {
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if (isupper(*p2))
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*p2 |= 040;
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++p2;
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}
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srvdata[0].data = realm;
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srvdata[0].length = strlen(realm);
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srvdata[1].data = "rcmd";
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srvdata[1].length = 4;
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srvdata[2].data = name;
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srvdata[2].length = p2 - name;
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server[0] = &srvdata[0];
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server[1] = &srvdata[1];
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server[2] = &srvdata[2];
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server[3] = 0;
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if (authdat)
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krb5_free_tkt_authent(authdat);
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if (r = krb5_rd_req_simple(&auth, server, 0, &authdat)) {
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char errbuf[128];
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authdat = 0;
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(void) strcpy(errbuf, "Read req failed: ");
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(void) strcat(errbuf, error_message(r));
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Data(ap, KRB_REJECT, errbuf, -1);
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if (auth_debug_mode)
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printf("%s\r\n", errbuf);
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return;
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}
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free(name);
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if (krb5_unparse_name(authdat->ticket->enc_part2 ->client,
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&name))
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name = 0;
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Data(ap, KRB_ACCEPT, name, name ? -1 : 0);
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if (auth_debug_mode) {
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printf("Kerberos5 accepting him as ``%s''\r\n",
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name ? name : "");
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}
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auth_finished(ap, AUTH_USER);
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if (authdat->ticket->enc_part2->session->keytype != KEYTYPE_DES)
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break;
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bcopy((void *)authdat->ticket->enc_part2->session->contents,
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(void *)session_key, sizeof(Block));
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break;
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case KRB_CHALLANGE:
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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 challange, 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 challange,
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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, challange, 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)challange[r] + 1;
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challange[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(challange, challange, sched, 1);
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Data(ap, KRB_RESPONSE, (void *)challange, sizeof(challange));
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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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kerberos5_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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Session_Key skey;
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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 V5 refuses authentication because %.*s ]\r\n",
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cnt, data);
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} else
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printf("[ Kerberos V5 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 V5 accepts you ]\n", cnt, data);
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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 challange.
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*/
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Data(ap, KRB_CHALLANGE, (void *)session_key,
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sizeof(session_key));
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#if defined(ENCRYPT)
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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
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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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/*
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* Verify that the response to the challange is correct.
|
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*/
|
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if ((cnt != sizeof(Block)) ||
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(0 != memcmp((void *)data, (void *)challange,
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sizeof(challange))))
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{
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printf("[ Kerberos V5 challange failed!!! ]\r\n");
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auth_send_retry();
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return;
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}
|
|
printf("[ Kerberos V5 challange successful ]\r\n");
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auth_finished(ap, AUTH_USER);
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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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kerberos5_status(ap, name, level)
|
|
Authenticator *ap;
|
|
char *name;
|
|
int level;
|
|
{
|
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if (level < AUTH_USER)
|
|
return(level);
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|
|
|
if (UserNameRequested &&
|
|
krb5_kuserok(authdat->ticket->enc_part2->client, 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
|
|
kerberos5_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;
|
|
}
|
|
}
|
|
#endif
|