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-rw-r--r--lib/libtelnet/kerberos.c519
1 files changed, 519 insertions, 0 deletions
diff --git a/lib/libtelnet/kerberos.c b/lib/libtelnet/kerberos.c
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+++ b/lib/libtelnet/kerberos.c
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+/*-
+ * 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.
+ */
+
+#include <sys/cdefs.h>
+
+#ifdef __FBSDID
+__FBSDID("$FreeBSD: src/crypto/telnet/libtelnet/kerberos.c,v 1.3.2.1 2002/04/13 10:59:07 markm Exp $");
+#endif
+
+#ifndef __unused
+#define __unused __attribute__((__unused__))
+#endif
+
+#ifndef lint
+static const char sccsid[] = "@(#)kerberos.c 8.3 (Berkeley) 5/30/95";
+#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 <des.h> /* BSD wont include this in krb.h, so we do it here */
+#include <krb.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "encrypt.h"
+#include "auth.h"
+#include "misc.h"
+
+int kerberos4_cksum(unsigned char *, int);
+int kuserok(AUTH_DAT *, char *);
+
+extern int auth_debug_mode;
+
+static unsigned char str_data[1024] = { IAC, SB, TELOPT_AUTHENTICATION, 0,
+ AUTHTYPE_KERBEROS_V4, };
+
+#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. */
+
+static KTEXT_ST auth;
+static char name[ANAME_SZ];
+static AUTH_DAT adat = { 0, "", "", "", 0, {}, 0, 0, 0, { 0, "", 0 } };
+#ifdef ENCRYPTION
+static Block session_key = { 0 };
+static des_key_schedule sched;
+static Block challenge = { 0 };
+#endif /* ENCRYPTION */
+
+static char krb_service_name[] = "rcmd";
+static char empty[] = "";
+
+static int
+Data(Authenticator *ap, int type, const unsigned char *d, int c)
+{
+ unsigned char *p = str_data + 4;
+ const unsigned char *cd = d;
+
+ if (c == -1)
+ c = strlen(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(Authenticator *ap __unused, 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(Authenticator *ap)
+{
+ KTEXT_ST lauth;
+ char instance[INST_SZ];
+ char *realm;
+ 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);
+ }
+
+ memset(instance, 0, 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(&lauth, 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", lauth.length);
+ if (!Data(ap, KRB_AUTH, (void *)lauth.dat, lauth.length)) {
+ if (auth_debug_mode)
+ printf("Not enough room for authentication data\r\n");
+ return(0);
+ }
+#ifdef ENCRYPTION
+ /*
+ * If we are doing mutual authentication, get set up to send
+ * the challenge, and verify it when the response comes back.
+ */
+ if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL) {
+ register int i;
+
+ des_key_sched(cred.session, sched);
+ des_init_random_number_generator(cred.session);
+ des_new_random_key(session_key);
+ des_ecb_encrypt(&session_key, &session_key, sched, 0);
+ des_ecb_encrypt(&session_key, &challenge, sched, 0);
+ /*
+ * Increment the challenge by 1, and encrypt it for
+ * later comparison.
+ */
+ for (i = 7; i >= 0; --i) {
+ register int x;
+ x = (unsigned int)challenge[i] + 1;
+ challenge[i] = x; /* ignore overflow */
+ if (x < 256) /* if no overflow, all done */
+ break;
+ }
+ des_ecb_encrypt(&challenge, &challenge, sched, 1);
+ }
+#endif /* ENCRYPTION */
+
+ if (auth_debug_mode) {
+ printf("CK: %d:", kerberos4_cksum(lauth.dat, lauth.length));
+ printd(lauth.dat, lauth.length);
+ printf("\r\n");
+ printf("Sent Kerberos V4 credentials to server\r\n");
+ }
+ return(1);
+}
+
+void
+kerberos4_is(Authenticator *ap, unsigned char *data, int cnt)
+{
+#ifdef ENCRYPTION
+ Session_Key skey;
+ Block datablock;
+#endif /* ENCRYPTION */
+ 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, "No local V4 Realm.", -1);
+ auth_finished(ap, AUTH_REJECT);
+ if (auth_debug_mode)
+ printf("No local realm\r\n");
+ return;
+ }
+ memmove((void *)auth.dat, (void *)data, 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, empty))) {
+ if (auth_debug_mode)
+ printf("Kerberos failed him as %s\r\n", name);
+ Data(ap, KRB_REJECT, krb_err_txt[r], -1);
+ auth_finished(ap, AUTH_REJECT);
+ return;
+ }
+#ifdef ENCRYPTION
+ memmove((void *)session_key, (void *)adat.session, sizeof(Block));
+#endif /* ENCRYPTION */
+ strncpy (name, adat.pname, ANAME_SZ-1);
+ name[ANAME_SZ-1] = '\0';
+
+ if (UserNameRequested && !kuserok(&adat, UserNameRequested))
+ Data(ap, KRB_ACCEPT, NULL, 0);
+ else
+ Data(ap, KRB_REJECT, "user is not authorized", -1);
+ auth_finished(ap, AUTH_USER);
+ break;
+
+ case KRB_CHALLENGE:
+#ifndef ENCRYPTION
+ Data(ap, KRB_RESPONSE, NULL, 0);
+#else /* ENCRYPTION */
+ if (!VALIDKEY(session_key)) {
+ /*
+ * We don't have a valid session key, so just
+ * send back a response with an empty session
+ * key.
+ */
+ Data(ap, KRB_RESPONSE, NULL, 0);
+ break;
+ }
+
+ /*
+ * Initialize the random number generator since it's
+ * used later on by the encryption routine.
+ */
+ des_init_random_number_generator(session_key);
+ des_key_sched(session_key, sched);
+ memmove((void *)datablock, (void *)data, sizeof(Block));
+ /*
+ * Take the received encrypted challenge, and encrypt
+ * it again to get a unique session_key for the
+ * ENCRYPT option.
+ */
+ des_ecb_encrypt(&datablock, &session_key, sched, 1);
+ skey.type = SK_DES;
+ skey.length = 8;
+ skey.data = session_key;
+ encrypt_session_key(&skey, 1);
+ /*
+ * Now decrypt the received encrypted challenge,
+ * increment by one, re-encrypt it and send it back.
+ */
+ des_ecb_encrypt(&datablock, &challenge, sched, 0);
+ for (r = 7; r >= 0; r--) {
+ register int t;
+ t = (unsigned int)challenge[r] + 1;
+ challenge[r] = t; /* ignore overflow */
+ if (t < 256) /* if no overflow, all done */
+ break;
+ }
+ des_ecb_encrypt(&challenge, &challenge, sched, 1);
+ Data(ap, KRB_RESPONSE, challenge, sizeof(challenge));
+#endif /* ENCRYPTION */
+ break;
+
+ default:
+ if (auth_debug_mode)
+ printf("Unknown Kerberos option %d\r\n", data[-1]);
+ Data(ap, KRB_REJECT, NULL, 0);
+ break;
+ }
+}
+
+void
+kerberos4_reply(Authenticator *ap, unsigned char *data, int cnt)
+{
+#ifdef ENCRYPTION
+ Session_Key skey;
+#endif /* ENCRYPTION */
+
+ 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.
+ */
+#ifndef ENCRYPTION
+ Data(ap, KRB_CHALLENGE, NULL, 0);
+#else /* ENCRYPTION */
+ Data(ap, KRB_CHALLENGE, session_key,
+ sizeof(session_key));
+ des_ecb_encrypt(&session_key, &session_key, sched, 1);
+ skey.type = SK_DES;
+ skey.length = 8;
+ skey.data = session_key;
+ encrypt_session_key(&skey, 0);
+#endif /* ENCRYPTION */
+ return;
+ }
+ auth_finished(ap, AUTH_USER);
+ return;
+ case KRB_RESPONSE:
+#ifdef ENCRYPTION
+ /*
+ * Verify that the response to the challenge is correct.
+ */
+ if ((cnt != sizeof(Block)) ||
+ (0 != memcmp((void *)data, (void *)challenge,
+ sizeof(challenge))))
+ {
+#endif /* ENCRYPTION */
+ printf("[ Kerberos V4 challenge failed!!! ]\r\n");
+ auth_send_retry();
+ return;
+#ifdef ENCRYPTION
+ }
+ printf("[ Kerberos V4 challenge successful ]\r\n");
+ auth_finished(ap, AUTH_USER);
+#endif /* ENCRYPTION */
+ break;
+ default:
+ if (auth_debug_mode)
+ printf("Unknown Kerberos option %d\r\n", data[-1]);
+ return;
+ }
+}
+
+int
+kerberos4_status(Authenticator *ap __unused, char *nam, int level)
+{
+ if (level < AUTH_USER)
+ return(level);
+
+ if (UserNameRequested && !kuserok(&adat, UserNameRequested)) {
+ strcpy(nam, 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(unsigned char *data, int cnt, unsigned char *buf, int 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(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)
+ do {
+ 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;
+ } while (n > 0);
+ return(ck);
+}
+#endif
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