#ifdef KRB4
#include <krb5.h>
#include <sys/types.h>
#include <errno.h>
#include <arpa/telnet.h>
#include <stdio.h>
#include <des.h>
#include <krb.h>
#ifdef __STDC__
#include <stdlib.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#else
#include <strings.h>
#endif
#include "encrypt.h"
#include "auth.h"
#include "misc.h"
extern int auth_debug_mode;
extern krb5_context telnet_context;
int kerberos4_cksum (unsigned char *, int);
static unsigned char str_data[1024] = { IAC, SB, TELOPT_AUTHENTICATION, 0,
AUTHTYPE_KERBEROS_V4, };
#if 0
static unsigned char str_name[1024] = { IAC, SB, TELOPT_AUTHENTICATION,
TELQUAL_NAME, };
#endif
#define KRB_AUTH 0
#define KRB_REJECT 1
#define KRB_ACCEPT 2
#define KRB_CHALLENGE 3
#define KRB_RESPONSE 4
#define KRB_SERVICE_NAME "rcmd"
static KTEXT_ST auth;
static char name[ANAME_SZ];
static AUTH_DAT adat = { 0 };
#ifdef ENCRYPTION
static Block session_key = { 0 };
static krb5_keyblock krbkey;
static Block challenge = { 0 };
#endif
static int
Data(ap, type, d, c)
Authenticator *ap;
int type;
const void *d;
int c;
{
unsigned char *p = str_data + 4;
const unsigned char *cd = (const unsigned char *)d;
size_t spaceleft = sizeof(str_data) - 4;
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;
spaceleft -= 3;
while (c-- > 0) {
if ((*p++ = *cd++) == IAC) {
*p++ = IAC;
spaceleft--;
}
if ((--spaceleft < 4) && c) {
errno = ENOMEM;
return -1;
}
}
*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(ap, server)
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;
}
kerberos5_init(NULL, server);
return(1);
}
char dst_realm_buf[REALM_SZ], *dest_realm = NULL;
unsigned int dst_realm_sz = REALM_SZ;
int
kerberos4_send(ap)
Authenticator *ap;
{
KTEXT_ST kauth;
char instance[INST_SZ];
char *realm;
char *krb_realmofhost();
char *krb_get_phost();
CREDENTIALS cred;
int r;
#ifdef ENCRYPTION
krb5_data data;
krb5_enc_data encdata;
krb5_error_code code;
krb5_keyblock rand_key;
#endif
printf("[ Trying KERBEROS4 ... ]\r\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(&kauth, KRB_SERVICE_NAME, instance, realm, 0))) {
printf("mk_req failed: %s\r\n", krb_get_err_text(r));
return(0);
}
if ((r = krb_get_cred(KRB_SERVICE_NAME, instance, realm, &cred))) {
printf("get_cred failed: %s\r\n", krb_get_err_text(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", kauth.length);
if (!Data(ap, KRB_AUTH, (void *)kauth.dat, kauth.length)) {
if (auth_debug_mode)
printf("Not enough room for authentication data\r\n");
return(0);
}
#ifdef ENCRYPTION
if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL) {
register int i;
data.data = cred.session;
data.length = 8; ;
if ((code = krb5_c_random_seed(telnet_context, &data))) {
com_err("libtelnet", code,
"while seeding random number generator");
return(0);
}
if ((code = krb5_c_make_random_key(telnet_context,
ENCTYPE_DES_CBC_RAW,
&rand_key))) {
com_err("libtelnet", code,
"while creating random session key");
return(0);
}
krbkey.enctype = ENCTYPE_DES_CBC_RAW;
krbkey.length = 8;
krbkey.contents = cred.session;
encdata.ciphertext.data = rand_key.contents;
encdata.ciphertext.length = rand_key.length;
encdata.enctype = ENCTYPE_UNKNOWN;
data.data = session_key;
data.length = 8;
code = krb5_c_decrypt(telnet_context, &krbkey, 0, 0,
&encdata, &data);
krb5_free_keyblock_contents(telnet_context, &rand_key);
if (code) {
com_err("libtelnet", code, "while encrypting random key");
return(0);
}
encdata.ciphertext.data = session_key;
encdata.ciphertext.length = 8;
encdata.enctype = ENCTYPE_UNKNOWN;
data.data = challenge;
data.length = 8;
code = krb5_c_decrypt(telnet_context, &krbkey, 0, 0,
&encdata, &data);
for (i = 7; i >= 0; --i) {
register int x;
x = (unsigned int)challenge[i] + 1;
challenge[i] = x;
if (x < 256)
break;
}
data.data = challenge;
data.length = 8;
encdata.ciphertext.data = challenge;
encdata.ciphertext.length = 8;
encdata.enctype = ENCTYPE_UNKNOWN;
if ((code = krb5_c_encrypt(telnet_context, &krbkey, 0, 0,
&data, &encdata))) {
com_err("libtelnet", code, "while encrypting random key");
return(0);
}
}
#endif
if (auth_debug_mode) {
printf("CK: %d:", kerberos4_cksum(kauth.dat, kauth.length));
printd(kauth.dat, kauth.length);
printf("\r\n");
printf("Sent Kerberos V4 credentials to server\r\n");
}
return(1);
}
void
kerberos4_is(ap, data, cnt)
Authenticator *ap;
unsigned char *data;
int cnt;
{
#ifdef ENCRYPTION
Session_Key skey;
Block datablock, tmpkey;
krb5_data kdata;
krb5_enc_data encdata;
krb5_error_code code;
#endif
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, (void *)"No local V4 Realm.", -1);
auth_finished(ap, AUTH_REJECT);
if (auth_debug_mode)
printf("No local realm\r\n");
return;
}
memcpy((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, ""))) {
if (auth_debug_mode)
printf("Kerberos failed him as %s\r\n", name);
Data(ap, KRB_REJECT, (const void *)krb_get_err_text(r), -1);
auth_finished(ap, AUTH_REJECT);
return;
}
#ifdef ENCRYPTION
memcpy((void *)session_key, (void *)adat.session, sizeof(Block));
#endif
krb_kntoln(&adat, name);
if (UserNameRequested && !kuserok(&adat, UserNameRequested))
Data(ap, KRB_ACCEPT, (void *)0, 0);
else
Data(ap, KRB_REJECT,
(void *)"user is not authorized", -1);
auth_finished(ap, AUTH_USER);
break;
case KRB_CHALLENGE:
#ifndef ENCRYPTION
Data(ap, KRB_RESPONSE, (void *)0, 0);
#else
if (!VALIDKEY(session_key)) {
Data(ap, KRB_RESPONSE, (void *)0, 0);
break;
}
kdata.data = session_key;
kdata.length = 8;
if ((code = krb5_c_random_seed(telnet_context, &kdata))) {
com_err("libtelnet", code,
"while seeding random number generator");
return;
}
memcpy((void *)datablock, (void *)data, sizeof(Block));
krbkey.enctype = ENCTYPE_DES_CBC_RAW;
krbkey.length = 8;
krbkey.contents = session_key;
kdata.data = datablock;
kdata.length = 8;
encdata.ciphertext.data = tmpkey;
encdata.ciphertext.length = 8;
encdata.enctype = ENCTYPE_UNKNOWN;
if ((code = krb5_c_encrypt(telnet_context, &krbkey, 0, 0,
&kdata, &encdata))) {
com_err("libtelnet", code, "while encrypting random key");
return;
}
skey.type = SK_DES;
skey.length = 8;
skey.data = tmpkey;
encrypt_session_key(&skey, 1);
encdata.ciphertext.data = datablock;
encdata.ciphertext.length = 8;
encdata.enctype = ENCTYPE_UNKNOWN;
kdata.data = challenge;
kdata.length = 8;
if ((code = krb5_c_decrypt(telnet_context, &krbkey, 0, 0,
&encdata, &kdata))) {
com_err("libtelnet", code, "while decrypting challenge");
return;
}
for (r = 7; r >= 0; r--) {
register int t;
t = (unsigned int)challenge[r] + 1;
challenge[r] = t;
if (t < 256)
break;
}
kdata.data = challenge;
kdata.length = 8;
encdata.ciphertext.data = challenge;
encdata.ciphertext.length = 8;
encdata.enctype = ENCTYPE_UNKNOWN;
if ((code = krb5_c_encrypt(telnet_context, &krbkey, 0, 0,
&kdata, &encdata))) {
com_err("libtelnet", code, "while decrypting challenge");
return;
}
Data(ap, KRB_RESPONSE, (void *)challenge, sizeof(challenge));
#endif
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(ap, data, cnt)
Authenticator *ap;
unsigned char *data;
int cnt;
{
#ifdef ENCRYPTION
Session_Key skey;
krb5_data kdata;
krb5_enc_data encdata;
krb5_error_code code;
#endif
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 ]\r\n");
if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL) {
#ifndef ENCRYPTION
Data(ap, KRB_CHALLENGE, (void *)0, 0);
#else
Data(ap, KRB_CHALLENGE, (void *)session_key,
sizeof(session_key));
kdata.data = session_key;
kdata.length = 8;
encdata.ciphertext.data = session_key;
encdata.ciphertext.length = 8;
encdata.enctype = ENCTYPE_UNKNOWN;
if ((code = krb5_c_encrypt(telnet_context, &krbkey,
0, 0, &kdata, &encdata))) {
com_err("libtelnet", code,
"while encrypting session_key");
return;
}
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:
#ifdef ENCRYPTION
if ((cnt != sizeof(Block)) ||
(0 != memcmp((void *)data, (void *)challenge,
sizeof(challenge))))
{
#endif
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
break;
default:
if (auth_debug_mode)
printf("Unknown Kerberos option %d\r\n", data[-1]);
return;
}
}
int
kerberos4_status(ap, kname, level)
Authenticator *ap;
char *kname;
int level;
{
if (level < AUTH_USER)
return(level);
if (UserNameRequested) {
strncpy(kname, UserNameRequested, 255);
kname[255] = '\0';
}
if (UserNameRequested && !kuserok(&adat, 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(data, cnt, buf, buflen)
unsigned char *data, *buf;
int cnt;
unsigned int buflen;
{
char lbuf[32];
register int i;
buf[buflen-1] = '\0';
buflen -= 1;
switch(data[3]) {
case KRB_REJECT:
strncpy((char *)buf, " REJECT ", buflen);
goto common;
case KRB_ACCEPT:
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:
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(d, n)
unsigned char *d;
int n;
{
int ck = 0;
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);
}
#else
#include <krb5.h>
#include <errno.h>
#endif
#ifdef notdef
prkey(msg, key)
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