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/*
* Copyright (c) 1995, 1996, 1997 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* 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. Neither the name of the Institute 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 INSTITUTE 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 INSTITUTE 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 "krb_locl.h"
RCSID("$Id: get_ad_tkt.c,v 1.22 1999/12/02 16:58:41 joda Exp $");
/*
* get_ad_tkt obtains a new service ticket from Kerberos, using
* the ticket-granting ticket which must be in the ticket file.
* It is typically called by krb_mk_req() when the client side
* of an application is creating authentication information to be
* sent to the server side.
*
* get_ad_tkt takes four arguments: three pointers to strings which
* contain the name, instance, and realm of the service for which the
* ticket is to be obtained; and an integer indicating the desired
* lifetime of the ticket.
*
* It returns an error status if the ticket couldn't be obtained,
* or AD_OK if all went well. The ticket is stored in the ticket
* cache.
*
* The request sent to the Kerberos ticket-granting service looks
* like this:
*
* pkt->dat
*
* TEXT original contents of authenticator+ticket
* pkt->dat built in krb_mk_req call
*
* 4 bytes time_ws always 0 (?)
* char lifetime lifetime argument passed
* string service service name argument
* string sinstance service instance arg.
*
* See "prot.h" for the reply packet layout and definitions of the
* extraction macros like pkt_version(), pkt_msg_type(), etc.
*/
int
get_ad_tkt(char *service, char *sinstance, char *realm, int lifetime)
{
static KTEXT_ST pkt_st;
KTEXT pkt = & pkt_st; /* Packet to KDC */
static KTEXT_ST rpkt_st;
KTEXT rpkt = &rpkt_st; /* Returned packet */
CREDENTIALS cr;
char lrealm[REALM_SZ];
u_int32_t time_ws = 0;
int kerror;
unsigned char *p;
size_t rem;
int tmp;
/*
* First check if we have a "real" TGT for the corresponding
* realm, if we don't, use ordinary inter-realm authentication.
*/
kerror = krb_get_cred(KRB_TICKET_GRANTING_TICKET, realm, realm, &cr);
if (kerror == KSUCCESS) {
strlcpy(lrealm, realm, REALM_SZ);
} else
kerror = krb_get_tf_realm(TKT_FILE, lrealm);
if (kerror != KSUCCESS)
return(kerror);
/*
* Look for the session key (and other stuff we don't need)
* in the ticket file for krbtgt.realm@lrealm where "realm"
* is the service's realm (passed in "realm" argument) and
* lrealm is the realm of our initial ticket. If we don't
* have this, we will try to get it.
*/
if ((kerror = krb_get_cred(KRB_TICKET_GRANTING_TICKET,
realm, lrealm, &cr)) != KSUCCESS) {
/*
* If realm == lrealm, we have no hope, so let's not even try.
*/
if ((strncmp(realm, lrealm, REALM_SZ)) == 0)
return(AD_NOTGT);
else{
if ((kerror =
get_ad_tkt(KRB_TICKET_GRANTING_TICKET,
realm, lrealm, lifetime)) != KSUCCESS) {
if (kerror == KDC_PR_UNKNOWN)
return(AD_INTR_RLM_NOTGT);
else
return(kerror);
}
if ((kerror = krb_get_cred(KRB_TICKET_GRANTING_TICKET,
realm, lrealm, &cr)) != KSUCCESS)
return(kerror);
}
}
/*
* Make up a request packet to the "krbtgt.realm@lrealm".
* Start by calling krb_mk_req() which puts ticket+authenticator
* into "pkt". Then tack other stuff on the end.
*/
kerror = krb_mk_req(pkt,
KRB_TICKET_GRANTING_TICKET,
realm,lrealm,0L);
if (kerror)
return(AD_NOTGT);
p = pkt->dat + pkt->length;
rem = sizeof(pkt->dat) - pkt->length;
tmp = krb_put_int(time_ws, p, rem, 4);
if (tmp < 0)
return KFAILURE;
p += tmp;
rem -= tmp;
tmp = krb_put_int(lifetime, p, rem, 1);
if (tmp < 0)
return KFAILURE;
p += tmp;
rem -= tmp;
tmp = krb_put_nir(service, sinstance, NULL, p, rem);
if (tmp < 0)
return KFAILURE;
p += tmp;
rem -= tmp;
pkt->length = p - pkt->dat;
rpkt->length = 0;
/* Send the request to the local ticket-granting server */
if ((kerror = send_to_kdc(pkt, rpkt, realm))) return(kerror);
/* check packet version of the returned packet */
{
KTEXT_ST cip;
CREDENTIALS cred;
struct timeval tv;
kerror = kdc_reply_cipher(rpkt, &cip);
if(kerror != KSUCCESS)
return kerror;
encrypt_ktext(&cip, &cr.session, DES_DECRYPT);
kerror = kdc_reply_cred(&cip, &cred);
if(kerror != KSUCCESS)
return kerror;
if (strcmp(cred.service, service) || strcmp(cred.instance, sinstance) ||
strcmp(cred.realm, realm)) /* not what we asked for */
return INTK_ERR; /* we need a better code here XXX */
krb_kdctimeofday(&tv);
if (abs((int)(tv.tv_sec - cred.issue_date)) > CLOCK_SKEW) {
return RD_AP_TIME; /* XXX should probably be better code */
}
kerror = save_credentials(cred.service, cred.instance, cred.realm,
cred.session, cred.lifetime, cred.kvno,
&cred.ticket_st, tv.tv_sec);
return kerror;
}
}
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