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| Current File : //usr/src/crypto/heimdal/appl/telnet/libtelnet/kerberos.c |
/*-
* Copyright (c) 1991, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* 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 HAVE_CONFIG_H
#include <config.h>
#endif
RCSID("$Id: kerberos.c 22071 2007-11-14 20:04:50Z lha $");
#ifdef KRB4
#ifdef HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif
#ifdef HAVE_ARPA_TELNET_H
#include <arpa/telnet.h>
#endif
#include <stdio.h>
#include <krb.h>
#include <pwd.h>
#include <stdlib.h>
#include <string.h>
#include <roken.h>
#ifdef SOCKS
#include <socks.h>
#endif
#include "encrypt.h"
#include "auth.h"
#include "misc.h"
int kerberos4_cksum (unsigned char *, int);
extern int auth_debug_mode;
static unsigned char str_data[2048] = { 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. */
#define KRB_FORWARD 5 /* */
#define KRB_FORWARD_ACCEPT 6 /* */
#define KRB_FORWARD_REJECT 7 /* */
#define KRB_SERVICE_NAME "rcmd"
static KTEXT_ST auth;
static char name[ANAME_SZ];
static AUTH_DAT adat;
static des_cblock session_key;
static des_cblock cred_session;
static des_key_schedule sched;
static des_cblock challenge;
static int auth_done; /* XXX */
static int pack_cred(CREDENTIALS *cred, unsigned char *buf);
static int unpack_cred(unsigned char *buf, int len, CREDENTIALS *cred);
static int
Data(Authenticator *ap, int type, const void *d, int c)
{
unsigned char *p = str_data + 4;
const unsigned char *cd = (const unsigned char *)d;
if (c == -1)
c = strlen((const 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(telnet_net_write(str_data, p - str_data));
}
int
kerberos4_init(Authenticator *ap, int server)
{
FILE *fp;
if (server) {
str_data[3] = TELQUAL_REPLY;
if ((fp = fopen(KEYFILE, "r")) == NULL)
return(0);
fclose(fp);
} else {
str_data[3] = TELQUAL_IS;
}
return(1);
}
char dst_realm_buf[REALM_SZ], *dest_realm = NULL;
int dst_realm_sz = REALM_SZ;
static int
kerberos4_send(char *name, Authenticator *ap)
{
KTEXT_ST auth;
char instance[INST_SZ];
char *realm;
CREDENTIALS cred;
int r;
if (!UserNameRequested) {
if (auth_debug_mode) {
printf("Kerberos V4: no user name supplied\r\n");
}
return(0);
}
memset(instance, 0, sizeof(instance));
strlcpy (instance,
krb_get_phost(RemoteHostName),
INST_SZ);
realm = dest_realm ? dest_realm : krb_realmofhost(RemoteHostName);
if (!realm) {
printf("Kerberos V4: no realm for %s\r\n", RemoteHostName);
return(0);
}
printf("[ Trying %s (%s.%s@%s) ... ]\r\n", name,
KRB_SERVICE_NAME, instance, realm);
r = krb_mk_req(&auth, KRB_SERVICE_NAME, instance, realm, 0L);
if (r) {
printf("mk_req failed: %s\r\n", krb_get_err_text(r));
return(0);
}
r = krb_get_cred(KRB_SERVICE_NAME, instance, realm, &cred);
if (r) {
printf("get_cred failed: %s\r\n", krb_get_err_text(r));
return(0);
}
if (!auth_sendname((unsigned char*)UserNameRequested,
strlen(UserNameRequested))) {
if (auth_debug_mode)
printf("Not enough room for user name\r\n");
return(0);
}
if (auth_debug_mode)
printf("Sent %d bytes of authentication data\r\n", auth.length);
if (!Data(ap, KRB_AUTH, (void *)auth.dat, auth.length)) {
if (auth_debug_mode)
printf("Not enough room for authentication data\r\n");
return(0);
}
#ifdef ENCRYPTION
/* create challenge */
if ((ap->way & AUTH_HOW_MASK)==AUTH_HOW_MUTUAL) {
int i;
des_key_sched(&cred.session, sched);
memcpy (&cred_session, &cred.session, sizeof(cred_session));
#ifndef HAVE_OPENSSL
des_init_random_number_generator(&cred.session);
#endif
des_new_random_key(&session_key);
des_ecb_encrypt(&session_key, &session_key, sched, 0);
des_ecb_encrypt(&session_key, &challenge, sched, 0);
/*
old code
Some CERT Advisory thinks this is a bad thing...
des_init_random_number_generator(&cred.session);
des_new_random_key(&challenge);
des_ecb_encrypt(&challenge, &session_key, sched, 1);
*/
/*
* Increment the challenge by 1, and encrypt it for
* later comparison.
*/
for (i = 7; i >= 0; --i)
if(++challenge[i] != 0) /* No carry! */
break;
des_ecb_encrypt(&challenge, &challenge, sched, 1);
}
#endif
if (auth_debug_mode) {
printf("CK: %d:", kerberos4_cksum(auth.dat, auth.length));
printd(auth.dat, auth.length);
printf("\r\n");
printf("Sent Kerberos V4 credentials to server\r\n");
}
return(1);
}
int
kerberos4_send_mutual(Authenticator *ap)
{
return kerberos4_send("mutual KERBEROS4", ap);
}
int
kerberos4_send_oneway(Authenticator *ap)
{
return kerberos4_send("KERBEROS4", ap);
}
void
kerberos4_is(Authenticator *ap, unsigned char *data, int cnt)
{
struct sockaddr_in addr;
char realm[REALM_SZ];
char instance[INST_SZ];
int r;
socklen_t addr_len;
if (cnt-- < 1)
return;
switch (*data++) {
case KRB_AUTH:
if (krb_get_lrealm(realm, 1) != KSUCCESS) {
Data(ap, KRB_REJECT, (void *)"No local V4 Realm.", -1);
auth_finished(ap, AUTH_REJECT);
if (auth_debug_mode)
printf("No local realm\r\n");
return;
}
memmove(auth.dat, 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");
}
k_getsockinst(0, instance, sizeof(instance));
addr_len = sizeof(addr);
if(getpeername(0, (struct sockaddr *)&addr, &addr_len) < 0) {
if(auth_debug_mode)
printf("getpeername failed\r\n");
Data(ap, KRB_REJECT, "getpeername failed", -1);
auth_finished(ap, AUTH_REJECT);
return;
}
if (addr.sin_family != AF_INET) {
if (auth_debug_mode)
printf("unknown address family: %d\r\n", addr.sin_family);
Data(ap, KRB_REJECT, "bad address family", -1);
auth_finished(ap, AUTH_REJECT);
return;
}
r = krb_rd_req(&auth, KRB_SERVICE_NAME,
instance, addr.sin_addr.s_addr, &adat, "");
if (r) {
if (auth_debug_mode)
printf("Kerberos failed him as %s\r\n", name);
Data(ap, KRB_REJECT, (void *)krb_get_err_text(r), -1);
auth_finished(ap, AUTH_REJECT);
return;
}
/* save the session key */
memmove(session_key, adat.session, sizeof(adat.session));
krb_kntoln(&adat, name);
if (UserNameRequested && !kuserok(&adat, UserNameRequested)){
char ts[MaxPathLen];
struct passwd *pw = getpwnam(UserNameRequested);
if(pw){
snprintf(ts, sizeof(ts),
"%s%u",
TKT_ROOT,
(unsigned)pw->pw_uid);
esetenv("KRBTKFILE", ts, 1);
if (pw->pw_uid == 0)
syslog(LOG_INFO|LOG_AUTH,
"ROOT Kerberos login from %s on %s\n",
krb_unparse_name_long(adat.pname,
adat.pinst,
adat.prealm),
RemoteHostName);
}
Data(ap, KRB_ACCEPT, NULL, 0);
} else {
char *msg;
int ret;
ret = asprintf (&msg, "user `%s' is not authorized to "
"login as `%s'",
krb_unparse_name_long(adat.pname,
adat.pinst,
adat.prealm),
UserNameRequested ? UserNameRequested : "<nobody>");
if (ret == -1)
Data(ap, KRB_REJECT, NULL, 0);
else {
Data(ap, KRB_REJECT, (void *)msg, -1);
free(msg);
}
auth_finished(ap, AUTH_REJECT);
break;
}
auth_finished(ap, AUTH_USER);
break;
case KRB_CHALLENGE:
#ifndef ENCRYPTION
Data(ap, KRB_RESPONSE, NULL, 0);
#else
if(!VALIDKEY(session_key)){
Data(ap, KRB_RESPONSE, NULL, 0);
break;
}
des_key_sched(&session_key, sched);
{
des_cblock d_block;
int i;
Session_Key skey;
memmove(d_block, data, sizeof(d_block));
/* make a session key for encryption */
des_ecb_encrypt(&d_block, &session_key, sched, 1);
skey.type=SK_DES;
skey.length=8;
skey.data=session_key;
encrypt_session_key(&skey, 1);
/* decrypt challenge, add one and encrypt it */
des_ecb_encrypt(&d_block, &challenge, sched, 0);
for (i = 7; i >= 0; i--)
if(++challenge[i] != 0)
break;
des_ecb_encrypt(&challenge, &challenge, sched, 1);
Data(ap, KRB_RESPONSE, (void *)challenge, sizeof(challenge));
}
#endif
break;
case KRB_FORWARD:
{
des_key_schedule ks;
unsigned char netcred[sizeof(CREDENTIALS)];
CREDENTIALS cred;
int ret;
if(cnt > sizeof(cred))
abort();
memcpy (session_key, adat.session, sizeof(session_key));
des_set_key(&session_key, ks);
des_pcbc_encrypt((void*)data, (void*)netcred, cnt,
ks, &session_key, DES_DECRYPT);
unpack_cred(netcred, cnt, &cred);
{
if(strcmp(cred.service, KRB_TICKET_GRANTING_TICKET) ||
strncmp(cred.instance, cred.realm, sizeof(cred.instance)) ||
cred.lifetime < 0 || cred.lifetime > 255 ||
cred.kvno < 0 || cred.kvno > 255 ||
cred.issue_date < 0 ||
cred.issue_date > time(0) + CLOCK_SKEW ||
strncmp(cred.pname, adat.pname, sizeof(cred.pname)) ||
strncmp(cred.pinst, adat.pinst, sizeof(cred.pinst))){
Data(ap, KRB_FORWARD_REJECT, "Bad credentials", -1);
}else{
if((ret = tf_setup(&cred,
cred.pname,
cred.pinst)) == KSUCCESS){
struct passwd *pw = getpwnam(UserNameRequested);
if (pw)
chown(tkt_string(), pw->pw_uid, pw->pw_gid);
Data(ap, KRB_FORWARD_ACCEPT, 0, 0);
} else{
Data(ap, KRB_FORWARD_REJECT,
krb_get_err_text(ret), -1);
}
}
}
memset(data, 0, cnt);
memset(&ks, 0, sizeof(ks));
memset(&cred, 0, sizeof(cred));
}
break;
default:
if (auth_debug_mode)
printf("Unknown Kerberos option %d\r\n", data[-1]);
Data(ap, KRB_REJECT, 0, 0);
break;
}
}
void
kerberos4_reply(Authenticator *ap, unsigned char *data, int cnt)
{
Session_Key skey;
if (cnt-- < 1)
return;
switch (*data++) {
case KRB_REJECT:
if(auth_done){ /* XXX Ick! */
printf("[ Kerberos V4 received unknown opcode ]\r\n");
}else{
printf("[ Kerberos V4 refuses authentication ");
if (cnt > 0)
printf("because %.*s ", cnt, data);
printf("]\r\n");
auth_send_retry();
}
return;
case KRB_ACCEPT:
printf("[ Kerberos V4 accepts you ]\r\n");
auth_done = 1;
if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL) {
/*
* Send over the encrypted challenge.
*/
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);
#if 0
kerberos4_forward(ap, &cred_session);
#endif
return;
}
auth_finished(ap, AUTH_USER);
return;
case KRB_RESPONSE:
/* make sure the response is correct */
if ((cnt != sizeof(des_cblock)) ||
(memcmp(data, challenge, sizeof(challenge)))){
printf("[ Kerberos V4 challenge failed!!! ]\r\n");
auth_send_retry();
return;
}
printf("[ Kerberos V4 challenge successful ]\r\n");
auth_finished(ap, AUTH_USER);
break;
case KRB_FORWARD_ACCEPT:
printf("[ Kerberos V4 accepted forwarded credentials ]\r\n");
break;
case KRB_FORWARD_REJECT:
printf("[ Kerberos V4 rejected forwarded credentials: `%.*s']\r\n",
cnt, data);
break;
default:
if (auth_debug_mode)
printf("Unknown Kerberos option %d\r\n", data[-1]);
return;
}
}
int
kerberos4_status(Authenticator *ap, char *name, size_t name_sz, int level)
{
if (level < AUTH_USER)
return(level);
if (UserNameRequested && !kuserok(&adat, UserNameRequested)) {
strlcpy(name, UserNameRequested, name_sz);
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)
{
int i;
buf[buflen-1] = '\0'; /* make sure it's NULL terminated */
buflen -= 1;
switch(data[3]) {
case KRB_REJECT: /* Rejected (reason might follow) */
strlcpy((char *)buf, " REJECT ", buflen);
goto common;
case KRB_ACCEPT: /* Accepted (name might follow) */
strlcpy((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 */
strlcpy((char *)buf, " AUTH", buflen);
goto common2;
case KRB_CHALLENGE:
strlcpy((char *)buf, " CHALLENGE", buflen);
goto common2;
case KRB_RESPONSE:
strlcpy((char *)buf, " RESPONSE", buflen);
goto common2;
default:
snprintf((char*)buf, buflen, " %d (unknown)", data[3]);
common2:
BUMP(buf, buflen);
for (i = 4; i < cnt; i++) {
snprintf((char*)buf, buflen, " %d", data[i]);
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)
while (n > 0) {
case 0:
ck ^= (int)*d++ << 24;
--n;
case 3:
ck ^= (int)*d++ << 16;
--n;
case 2:
ck ^= (int)*d++ << 8;
--n;
case 1:
ck ^= (int)*d++;
--n;
}
return(ck);
}
static int
pack_cred(CREDENTIALS *cred, unsigned char *buf)
{
unsigned char *p = buf;
memcpy (p, cred->service, ANAME_SZ);
p += ANAME_SZ;
memcpy (p, cred->instance, INST_SZ);
p += INST_SZ;
memcpy (p, cred->realm, REALM_SZ);
p += REALM_SZ;
memcpy(p, cred->session, 8);
p += 8;
p += KRB_PUT_INT(cred->lifetime, p, 4, 4);
p += KRB_PUT_INT(cred->kvno, p, 4, 4);
p += KRB_PUT_INT(cred->ticket_st.length, p, 4, 4);
memcpy(p, cred->ticket_st.dat, cred->ticket_st.length);
p += cred->ticket_st.length;
p += KRB_PUT_INT(0, p, 4, 4);
p += KRB_PUT_INT(cred->issue_date, p, 4, 4);
memcpy (p, cred->pname, ANAME_SZ);
p += ANAME_SZ;
memcpy (p, cred->pinst, INST_SZ);
p += INST_SZ;
return p - buf;
}
static int
unpack_cred(unsigned char *buf, int len, CREDENTIALS *cred)
{
char *p = (char*)buf;
uint32_t tmp;
strncpy (cred->service, p, ANAME_SZ);
cred->service[ANAME_SZ - 1] = '\0';
p += ANAME_SZ;
strncpy (cred->instance, p, INST_SZ);
cred->instance[INST_SZ - 1] = '\0';
p += INST_SZ;
strncpy (cred->realm, p, REALM_SZ);
cred->realm[REALM_SZ - 1] = '\0';
p += REALM_SZ;
memcpy(cred->session, p, 8);
p += 8;
p += krb_get_int(p, &tmp, 4, 0);
cred->lifetime = tmp;
p += krb_get_int(p, &tmp, 4, 0);
cred->kvno = tmp;
p += krb_get_int(p, &cred->ticket_st.length, 4, 0);
memcpy(cred->ticket_st.dat, p, cred->ticket_st.length);
p += cred->ticket_st.length;
p += krb_get_int(p, &tmp, 4, 0);
cred->ticket_st.mbz = 0;
p += krb_get_int(p, (uint32_t *)&cred->issue_date, 4, 0);
strncpy (cred->pname, p, ANAME_SZ);
cred->pname[ANAME_SZ - 1] = '\0';
p += ANAME_SZ;
strncpy (cred->pinst, p, INST_SZ);
cred->pinst[INST_SZ - 1] = '\0';
p += INST_SZ;
return 0;
}
int
kerberos4_forward(Authenticator *ap, void *v)
{
des_cblock *key = (des_cblock *)v;
CREDENTIALS cred;
char *realm;
des_key_schedule ks;
int len;
unsigned char netcred[sizeof(CREDENTIALS)];
int ret;
realm = krb_realmofhost(RemoteHostName);
if(realm == NULL)
return -1;
memset(&cred, 0, sizeof(cred));
ret = krb_get_cred(KRB_TICKET_GRANTING_TICKET,
realm,
realm,
&cred);
if(ret)
return ret;
des_set_key(key, ks);
len = pack_cred(&cred, netcred);
des_pcbc_encrypt((void*)netcred, (void*)netcred, len,
ks, key, DES_ENCRYPT);
memset(&ks, 0, sizeof(ks));
Data(ap, KRB_FORWARD, netcred, len);
memset(netcred, 0, sizeof(netcred));
return 0;
}
#endif /* KRB4 */