Net2/usr/src/lib/libtelnet/kerberos5.c
/*-
* Copyright (c) 1991 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef lint
static char sccsid[] = "@(#)kerberos5.c 5.2 (Berkeley) 3/22/91";
#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 KRB5
#include <arpa/telnet.h>
#include <stdio.h>
#include <krb5/krb5.h>
#include <krb5/crc-32.h>
#include <krb5/libos-proto.h>
#include <netdb.h>
#include <ctype.h>
#ifdef __STDC__
#include <stdlib.h>
#endif
#ifdef NO_STRING_H
#include <strings.h>
#else
#include <string.h>
#endif
#include "encrypt.h"
#include "auth.h"
#include "misc.h"
extern auth_debug_mode;
char *malloc();
static unsigned char str_data[1024] = { IAC, SB, TELOPT_AUTHENTICATION, 0,
AUTHTYPE_KERBEROS_V5, };
static unsigned char str_name[1024] = { IAC, SB, TELOPT_AUTHENTICATION,
TELQUAL_NAME, };
#define KRB_AUTH 0 /* Authentication data follows */
#define KRB_REJECT 1 /* Rejected (reason might follow) */
#define KRB_ACCEPT 2 /* Accepted */
#define KRB_CHALLANGE 3 /* Challange for mutual auth. */
#define KRB_RESPONSE 4 /* Response for mutual auth. */
static krb5_data auth;
/* telnetd gets session key from here */
static krb5_tkt_authent *authdat = NULL;
#if defined(ENCRYPT)
Block session_key;
#endif
static Schedule sched;
static Block challange;
static int
Data(ap, type, d, c)
Authenticator *ap;
int type;
void *d;
int c;
{
unsigned char *p = str_data + 4;
unsigned char *cd = (unsigned char *)d;
if (c == -1)
c = strlen((char *)cd);
if (auth_debug_mode) {
printf("%s:%d: [%d] (%d)",
str_data[3] == TELQUAL_IS ? ">>>IS" : ">>>REPLY",
str_data[3],
type, c);
printd(d, c);
printf("\r\n");
}
*p++ = ap->type;
*p++ = ap->way;
*p++ = type;
while (c-- > 0) {
if ((*p++ = *cd++) == IAC)
*p++ = IAC;
}
*p++ = IAC;
*p++ = SE;
if (str_data[3] == TELQUAL_IS)
printsub('>', &str_data[2], p - &str_data[2]);
return(net_write(str_data, p - str_data));
}
int
kerberos5_init(ap, server)
Authenticator *ap;
int server;
{
if (server)
str_data[3] = TELQUAL_REPLY;
else
str_data[3] = TELQUAL_IS;
krb5_init_ets();
return(1);
}
int
kerberos5_send(ap)
Authenticator *ap;
{
char **realms;
char *name;
char *p1, *p2;
krb5_checksum ksum;
krb5_octet sum[CRC32_CKSUM_LENGTH];
krb5_data *server[4];
krb5_data srvdata[3];
krb5_error_code r;
krb5_ccache ccache;
krb5_creds creds; /* telnet gets session key from here */
extern krb5_flags krb5_kdc_default_options;
ksum.checksum_type = CKSUMTYPE_CRC32;
ksum.contents = sum;
ksum.length = sizeof(sum);
bzero((void *)sum, sizeof(sum));
if (!UserNameRequested) {
if (auth_debug_mode) {
printf("Kerberos V5: no user name supplied\r\n");
}
return(0);
}
if (r = krb5_cc_default(&ccache)) {
if (auth_debug_mode) {
printf("Kerberos V5: could not get default ccache\r\n");
}
return(0);
}
if ((name = malloc(strlen(RemoteHostName)+1)) == NULL) {
if (auth_debug_mode)
printf("Out of memory for hostname in Kerberos V5\r\n");
return(0);
}
if (r = krb5_get_host_realm(RemoteHostName, &realms)) {
if (auth_debug_mode)
printf("Kerberos V5: no realm for %s\r\n", RemoteHostName);
free(name);
return(0);
}
p1 = RemoteHostName;
p2 = name;
while (*p2 = *p1++) {
if (isupper(*p2))
*p2 |= 040;
++p2;
}
srvdata[0].data = realms[0];
srvdata[0].length = strlen(realms[0]);
srvdata[1].data = "rcmd";
srvdata[1].length = 4;
srvdata[2].data = name;
srvdata[2].length = p2 - name;
server[0] = &srvdata[0];
server[1] = &srvdata[1];
server[2] = &srvdata[2];
server[3] = 0;
bzero((char *)&creds, sizeof(creds));
creds.server = (krb5_principal)server;
if (r = krb5_cc_get_principal(ccache, &creds.client)) {
if (auth_debug_mode) {
printf("Keberos V5: failure on principal (%d)\r\n",
error_message(r));
}
free(name);
krb5_free_host_realm(realms);
return(0);
}
if (r = krb5_get_credentials(krb5_kdc_default_options, ccache, &creds)) {
if (auth_debug_mode) {
printf("Keberos V5: failure on credentials(%d)\r\n",r);
}
free(name);
krb5_free_host_realm(realms);
return(0);
}
r = krb5_mk_req_extended(0, &ksum, &creds.times,
krb5_kdc_default_options,
ccache, &creds, 0, &auth);
free(name);
krb5_free_host_realm(realms);
if (r) {
if (auth_debug_mode) {
printf("Keberos V5: mk_req failed\r\n");
}
return(0);
}
if (!auth_sendname(UserNameRequested, strlen(UserNameRequested))) {
if (auth_debug_mode)
printf("Not enough room for user name\r\n");
return(0);
}
if (!Data(ap, KRB_AUTH, auth.data, auth.length)) {
if (auth_debug_mode)
printf("Not enough room for authentication data\r\n");
return(0);
}
/*
* If we are doing mutual authentication, get set up to send
* the challange, and verify it when the response comes back.
*/
if (((ap->way & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL)
&& (creds.keyblock.keytype == KEYTYPE_DES)) {
register int i;
des_key_sched(creds.keyblock.contents, sched);
des_set_random_generator_seed(creds.keyblock.contents);
des_new_random_key(challange);
des_ecb_encrypt(challange, session_key, sched, 1);
/*
* Increment the challange by 1, and encrypt it for
* later comparison.
*/
for (i = 7; i >= 0; --i) {
register int x;
x = (unsigned int)challange[i] + 1;
challange[i] = x; /* ignore overflow */
if (x < 256) /* if no overflow, all done */
break;
}
des_ecb_encrypt(challange, challange, sched, 1);
}
if (auth_debug_mode) {
printf("Sent Kerberos V5 credentials to server\r\n");
}
return(1);
}
void
kerberos5_is(ap, data, cnt)
Authenticator *ap;
unsigned char *data;
int cnt;
{
int r;
struct hostent *hp;
char *p1, *p2;
static char *realm = NULL;
krb5_data *server[4];
krb5_data srvdata[3];
Session_Key skey;
char *name;
char *getenv();
if (cnt-- < 1)
return;
switch (*data++) {
case KRB_AUTH:
auth.data = (char *)data;
auth.length = cnt;
if (!(hp = gethostbyname(LocalHostName))) {
if (auth_debug_mode)
printf("Cannot resolve local host name\r\n");
Data(ap, KRB_REJECT, "Unknown local hostname.", -1);
auth_finished(ap, AUTH_REJECT);
return;
}
if (!realm && (krb5_get_default_realm(&realm))) {
if (auth_debug_mode)
printf("Could not get defualt realm\r\n");
Data(ap, KRB_REJECT, "Could not get default realm.", -1);
auth_finished(ap, AUTH_REJECT);
return;
}
if ((name = malloc(strlen(hp->h_name)+1)) == NULL) {
if (auth_debug_mode)
printf("Out of memory for hostname in Kerberos V5\r\n");
Data(ap, KRB_REJECT, "Out of memory.", -1);
auth_finished(ap, AUTH_REJECT);
return;
}
p1 = hp->h_name;
p2 = name;
while (*p2 = *p1++) {
if (isupper(*p2))
*p2 |= 040;
++p2;
}
srvdata[0].data = realm;
srvdata[0].length = strlen(realm);
srvdata[1].data = "rcmd";
srvdata[1].length = 4;
srvdata[2].data = name;
srvdata[2].length = p2 - name;
server[0] = &srvdata[0];
server[1] = &srvdata[1];
server[2] = &srvdata[2];
server[3] = 0;
if (authdat)
krb5_free_tkt_authent(authdat);
if (r = krb5_rd_req_simple(&auth, server, 0, &authdat)) {
char errbuf[128];
authdat = 0;
(void) strcpy(errbuf, "Read req failed: ");
(void) strcat(errbuf, error_message(r));
Data(ap, KRB_REJECT, errbuf, -1);
if (auth_debug_mode)
printf("%s\r\n", errbuf);
return;
}
free(name);
if (krb5_unparse_name(authdat->ticket->enc_part2 ->client,
&name))
name = 0;
Data(ap, KRB_ACCEPT, name, name ? -1 : 0);
if (auth_debug_mode) {
printf("Kerberos5 accepting him as ``%s''\r\n",
name ? name : "");
}
auth_finished(ap, AUTH_USER);
if (authdat->ticket->enc_part2->session->keytype != KEYTYPE_DES)
break;
bcopy((void *)authdat->ticket->enc_part2->session->contents,
(void *)session_key, sizeof(Block));
break;
case KRB_CHALLANGE:
if (!VALIDKEY(session_key)) {
/*
* We don't have a valid session key, so just
* send back a response with an empty session
* key.
*/
Data(ap, KRB_RESPONSE, (void *)0, 0);
break;
}
des_key_sched(session_key, sched);
bcopy((void *)data, (void *)datablock, sizeof(Block));
/*
* Take the received encrypted challange, and encrypt
* it again to get a unique session_key for the
* ENCRYPT option.
*/
des_ecb_encrypt(datablock, session_key, sched, 1);
skey.type = SK_DES;
skey.length = 8;
skey.data = session_key;
encrypt_session_key(&skey, 1);
/*
* Now decrypt the received encrypted challange,
* increment by one, re-encrypt it and send it back.
*/
des_ecb_encrypt(datablock, challange, sched, 0);
for (r = 7; r >= 0; r++) {
register int t;
t = (unsigned int)challange[r] + 1;
challange[r] = t; /* ignore overflow */
if (t < 256) /* if no overflow, all done */
break;
}
des_ecb_encrypt(challange, challange, sched, 1);
Data(ap, KRB_RESPONSE, (void *)challange, sizeof(challange));
break;
default:
if (auth_debug_mode)
printf("Unknown Kerberos option %d\r\n", data[-1]);
Data(ap, KRB_REJECT, 0, 0);
break;
}
}
void
kerberos5_reply(ap, data, cnt)
Authenticator *ap;
unsigned char *data;
int cnt;
{
Session_Key skey;
if (cnt-- < 1)
return;
switch (*data++) {
case KRB_REJECT:
if (cnt > 0) {
printf("[ Kerberos V5 refuses authentication because %.*s ]\r\n",
cnt, data);
} else
printf("[ Kerberos V5 refuses authentication ]\r\n");
auth_send_retry();
return;
case KRB_ACCEPT:
printf("[ Kerberos V5 accepts you ]\n", cnt, data);
if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL) {
/*
* Send over the encrypted challange.
*/
Data(ap, KRB_CHALLANGE, (void *)session_key,
sizeof(session_key));
#if defined(ENCRYPT)
des_ecb_encrypt(session_key, session_key, sched, 1);
skey.type = SK_DES;
skey.length = 8;
skey.data = session_key;
encrypt_session_key(&skey, 0);
#endif
return;
}
auth_finished(ap, AUTH_USER);
return;
case KRB_RESPONSE:
/*
* Verify that the response to the challange is correct.
*/
if ((cnt != sizeof(Block)) ||
(0 != memcmp((void *)data, (void *)challange,
sizeof(challange))))
{
printf("[ Kerberos V5 challange failed!!! ]\r\n");
auth_send_retry();
return;
}
printf("[ Kerberos V5 challange successful ]\r\n");
auth_finished(ap, AUTH_USER);
break;
default:
if (auth_debug_mode)
printf("Unknown Kerberos option %d\r\n", data[-1]);
return;
}
}
int
kerberos5_status(ap, name, level)
Authenticator *ap;
char *name;
int level;
{
if (level < AUTH_USER)
return(level);
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