freebsd-skq/crypto/telnet/libtelnet/kerberos5.c
markm 2ea49f693f Initial import of BSD telnet. This will be used to build the kerberised
telnet, and after userland diffs have been merged in, will be used to
build the non-kerberised sources as well. (See unifdef(1) for details)
1997-09-04 06:11:16 +00:00

765 lines
20 KiB
C

/*
* $Source: /mit/krb5/.cvsroot/src/appl/telnet/libtelnet/kerberos5.c,v $
* $Author: tytso $
* $Id: kerberos5.c,v 1.1 1997/09/04 06:11:15 markm Exp $
*/
#if !defined(lint) && !defined(SABER)
static
#ifdef __STDC__
const
#endif
char rcsid_kerberos5_c[] = "$Id: kerberos5.c,v 1.1 1997/09/04 06:11:15 markm Exp $";
#endif /* lint */
/*-
* 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.
*/
#ifndef lint
static char sccsid[] = "@(#)kerberos5.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 may
* 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/asn1.h>
#include <krb5/crc-32.h>
#include <krb5/los-proto.h>
#include <krb5/ext-proto.h>
#include <com_err.h>
#include <netdb.h>
#include <ctype.h>
/* kerberos 5 include files (ext-proto.h) will get an appropriate stdlib.h
and string.h/strings.h */
#include "encrypt.h"
#include "auth.h"
#include "misc.h"
extern auth_debug_mode;
#ifdef FORWARD
int forward_flags = 0; /* Flags get set in telnet/main.c on -f and -F */
/* These values need to be the same as those defined in telnet/main.c. */
/* Either define them in both places, or put in some common header file. */
#define OPTS_FORWARD_CREDS 0x00000002
#define OPTS_FORWARDABLE_CREDS 0x00000001
void kerberos5_forward();
#endif /* FORWARD */
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_RESPONSE 3 /* Response for mutual auth. */
#ifdef FORWARD
#define KRB_FORWARD 4 /* Forwarded credentials follow */
#define KRB_FORWARD_ACCEPT 5 /* Forwarded credentials accepted */
#define KRB_FORWARD_REJECT 6 /* Forwarded credentials rejected */
#endif /* FORWARD */
static krb5_data auth;
/* telnetd gets session key from here */
static krb5_tkt_authent *authdat = NULL;
/* telnet matches the AP_REQ and AP_REP with this */
static krb5_authenticator authenticator;
/* some compilers can't hack void *, so we use the Kerberos krb5_pointer,
which is either void * or char *, depending on the compiler. */
#define Voidptr krb5_pointer
Block session_key;
static int
Data(ap, type, d, c)
Authenticator *ap;
int type;
Voidptr 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_principal server;
krb5_error_code r;
krb5_ccache ccache;
krb5_creds creds; /* telnet gets session key from here */
extern krb5_flags krb5_kdc_default_options;
int ap_opts;
#ifdef ENCRYPTION
krb5_keyblock *newkey = 0;
#endif /* ENCRYPTION */
ksum.checksum_type = CKSUMTYPE_CRC32;
ksum.contents = sum;
ksum.length = sizeof(sum);
memset((Voidptr )sum, 0, 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;
}
if (r = krb5_build_principal_ext(&server,
strlen(realms[0]), realms[0],
4, "host",
p2 - name, name,
0)) {
if (auth_debug_mode) {
printf("Kerberos V5: failure setting up principal (%s)\r\n",
error_message(r));
}
free(name);
krb5_free_host_realm(realms);
return(0);
}
memset((char *)&creds, 0, sizeof(creds));
creds.server = server;
if (r = krb5_cc_get_principal(ccache, &creds.client)) {
if (auth_debug_mode) {
printf("Kerberos V5: failure on principal (%s)\r\n",
error_message(r));
}
free(name);
krb5_free_principal(server);
krb5_free_host_realm(realms);
return(0);
}
if (r = krb5_get_credentials(krb5_kdc_default_options, ccache, &creds)) {
if (auth_debug_mode) {
printf("Kerberos V5: failure on credentials(%d)\r\n",r);
}
free(name);
krb5_free_host_realm(realms);
krb5_free_principal(server);
return(0);
}
if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL)
ap_opts = AP_OPTS_MUTUAL_REQUIRED;
else
ap_opts = 0;
r = krb5_mk_req_extended(ap_opts, &ksum, krb5_kdc_default_options, 0,
#ifdef ENCRYPTION
&newkey,
#else /* ENCRYPTION */
0,
#endif /* ENCRYPTION */
ccache, &creds, &authenticator, &auth);
/* don't let the key get freed if we clean up the authenticator */
authenticator.subkey = 0;
free(name);
krb5_free_host_realm(realms);
krb5_free_principal(server);
#ifdef ENCRYPTION
if (newkey) {
/* keep the key in our private storage, but don't use it
yet---see kerberos5_reply() below */
if (newkey->keytype != KEYTYPE_DES) {
if (creds.keyblock.keytype == KEYTYPE_DES)
/* use the session key in credentials instead */
memmove((char *)session_key,
(char *)creds.keyblock.contents, sizeof(Block));
else
/* XXX ? */;
} else {
memmove((char *)session_key, (char *)newkey->contents,
sizeof(Block));
}
krb5_free_keyblock(newkey);
}
#endif /* ENCRYPTION */
if (r) {
if (auth_debug_mode) {
printf("Kerberos V5: mk_req failed (%s)\r\n",
error_message(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 (!Data(ap, KRB_AUTH, auth.data, auth.length)) {
if (auth_debug_mode)
printf("Not enough room for authentication data\r\n");
return(0);
}
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_principal server;
krb5_ap_rep_enc_part reply;
krb5_data outbuf;
#ifdef ENCRYPTION
Session_Key skey;
#endif /* ENCRYPTION */
char *name;
char *getenv();
krb5_data inbuf;
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 default 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;
}
if (authdat)
krb5_free_tkt_authent(authdat);
r = krb5_build_principal_ext(&server,
strlen(realm), realm,
4, "host",
p2 - name, name,
0);
if (!r) {
r = krb5_rd_req_simple(&auth, server, 0, &authdat);
krb5_free_principal(server);
}
if (r) {
char errbuf[128];
errout:
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 ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL) {
/* do ap_rep stuff here */
reply.ctime = authdat->authenticator->ctime;
reply.cusec = authdat->authenticator->cusec;
reply.subkey = 0; /* use the one he gave us, so don't
need to return one here */
reply.seq_number = 0; /* we don't do seq #'s. */
if (r = krb5_mk_rep(&reply,
authdat->authenticator->subkey ?
authdat->authenticator->subkey :
authdat->ticket->enc_part2->session,
&outbuf)) {
goto errout;
}
Data(ap, KRB_RESPONSE, outbuf.data, outbuf.length);
}
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 identifies him as ``%s''\r\n",
name ? name : "");
}
auth_finished(ap, AUTH_USER);
free(name);
if (authdat->authenticator->subkey &&
authdat->authenticator->subkey->keytype == KEYTYPE_DES) {
memmove((Voidptr )session_key,
(Voidptr )authdat->authenticator->subkey->contents,
sizeof(Block));
} else if (authdat->ticket->enc_part2->session->keytype ==
KEYTYPE_DES) {
memmove((Voidptr )session_key,
(Voidptr )authdat->ticket->enc_part2->session->contents,
sizeof(Block));
} else
break;
#ifdef ENCRYPTION
skey.type = SK_DES;
skey.length = 8;
skey.data = session_key;
encrypt_session_key(&skey, 1);
#endif /* ENCRYPTION */
break;
#ifdef FORWARD
case KRB_FORWARD:
inbuf.data = (char *)data;
inbuf.length = cnt;
if (r = rd_and_store_for_creds(&inbuf, authdat->ticket,
UserNameRequested)) {
char errbuf[128];
(void) strcpy(errbuf, "Read forwarded creds failed: ");
(void) strcat(errbuf, error_message(r));
Data(ap, KRB_FORWARD_REJECT, errbuf, -1);
if (auth_debug_mode)
printf("Could not read forwarded credentials\r\n");
}
else
Data(ap, KRB_FORWARD_ACCEPT, 0, 0);
if (auth_debug_mode)
printf("Forwarded credentials obtained\r\n");
break;
#endif /* FORWARD */
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;
static int mutual_complete = 0;
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:
if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL &&
!mutual_complete) {
printf("[ Kerberos V5 accepted you, but didn't provide mutual authentication! ]\n");
auth_send_retry();
return;
}
if (cnt)
printf("[ Kerberos V5 accepts you as ``%.*s'' ]\n", cnt, data);
else
printf("[ Kerberos V5 accepts you ]\n");
auth_finished(ap, AUTH_USER);
#ifdef FORWARD
if (forward_flags & OPTS_FORWARD_CREDS)
kerberos5_forward(ap);
#endif /* FORWARD */
break;
case KRB_RESPONSE:
if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL) {
/* the rest of the reply should contain a krb_ap_rep */
krb5_ap_rep_enc_part *reply;
krb5_data inbuf;
krb5_error_code r;
krb5_keyblock tmpkey;
inbuf.length = cnt;
inbuf.data = (char *)data;
tmpkey.keytype = KEYTYPE_DES;
tmpkey.contents = session_key;
tmpkey.length = sizeof(Block);
if (r = krb5_rd_rep(&inbuf, &tmpkey, &reply)) {
printf("[ Mutual authentication failed: %s ]\n",
error_message(r));
auth_send_retry();
return;
}
if (reply->ctime != authenticator.ctime ||
reply->cusec != authenticator.cusec) {
printf("[ Mutual authentication failed (mismatched KRB_AP_REP) ]\n");
auth_send_retry();
return;
}
krb5_free_ap_rep_enc_part(reply);
#ifdef ENCRYPTION
skey.type = SK_DES;
skey.length = 8;
skey.data = session_key;
encrypt_session_key(&skey, 0);
#endif /* ENCRYPTION */
mutual_complete = 1;
}
return;
#ifdef FORWARD
case KRB_FORWARD_ACCEPT:
printf("[ Kerberos V5 accepted forwarded credentials ]\n");
return;
case KRB_FORWARD_REJECT:
printf("[ Kerberos V5 refuses forwarded credentials because %.*s ]\r\n",
cnt, data);
return;
#endif /* FORWARD */
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_RESPONSE:
strncpy((char *)buf, " RESPONSE", buflen);
goto common2;
#ifdef FORWARD
case KRB_FORWARD: /* Forwarded credentials follow */
strncpy((char *)buf, " FORWARD", buflen);
goto common2;
case KRB_FORWARD_ACCEPT: /* Forwarded credentials accepted */
strncpy((char *)buf, " FORWARD_ACCEPT", buflen);
goto common2;
case KRB_FORWARD_REJECT: /* Forwarded credentials rejected */
/* (reason might follow) */
strncpy((char *)buf, " FORWARD_REJECT", buflen);
goto common2;
#endif /* FORWARD */
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;
}
}
#ifdef FORWARD
void
kerberos5_forward(ap)
Authenticator *ap;
{
struct hostent *hp;
krb5_creds *local_creds;
krb5_error_code r;
krb5_data forw_creds;
extern krb5_cksumtype krb5_kdc_req_sumtype;
krb5_ccache ccache;
int i;
if (!(local_creds = (krb5_creds *)
calloc(1, sizeof(*local_creds)))) {
if (auth_debug_mode)
printf("Kerberos V5: could not allocate memory for credentials\r\n");
return;
}
if (r = krb5_sname_to_principal(RemoteHostName, "host", 1,
&local_creds->server)) {
if (auth_debug_mode)
printf("Kerberos V5: could not build server name - %s\r\n",
error_message(r));
krb5_free_creds(local_creds);
return;
}
if (r = krb5_cc_default(&ccache)) {
if (auth_debug_mode)
printf("Kerberos V5: could not get default ccache - %s\r\n",
error_message(r));
krb5_free_creds(local_creds);
return;
}
if (r = krb5_cc_get_principal(ccache, &local_creds->client)) {
if (auth_debug_mode)
printf("Kerberos V5: could not get default principal - %s\r\n",
error_message(r));
krb5_free_creds(local_creds);
return;
}
/* Get ticket from credentials cache */
if (r = krb5_get_credentials(KRB5_GC_CACHED, ccache, local_creds)) {
if (auth_debug_mode)
printf("Kerberos V5: could not obtain credentials - %s\r\n",
error_message(r));
krb5_free_creds(local_creds);
return;
}
if (r = get_for_creds(ETYPE_DES_CBC_CRC,
krb5_kdc_req_sumtype,
RemoteHostName,
local_creds->client,
&local_creds->keyblock,
forward_flags & OPTS_FORWARDABLE_CREDS,
&forw_creds)) {
if (auth_debug_mode)
printf("Kerberos V5: error getting forwarded creds - %s\r\n",
error_message(r));
krb5_free_creds(local_creds);
return;
}
/* Send forwarded credentials */
if (!Data(ap, KRB_FORWARD, forw_creds.data, forw_creds.length)) {
if (auth_debug_mode)
printf("Not enough room for authentication data\r\n");
}
else {
if (auth_debug_mode)
printf("Forwarded local Kerberos V5 credentials to server\r\n");
}
krb5_free_creds(local_creds);
}
#endif /* FORWARD */
#endif /* KRB5 */