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/*
* lib/krb4/cr_auth_repl.c
*
* Copyright 1985, 1986, 1987, 1988, 2000 by the Massachusetts
* Institute of Technology. All Rights Reserved.
*
* 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. Furthermore if you modify this software you must label
* your software as modified software and not distribute it in such a
* fashion that it might be confused with the original M.I.T. software.
* 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.
*/
#include "krb.h"
#include "prot.h"
#include <string.h>
/*
* This routine is called by the Kerberos authentication server
* to create a reply to an authentication request. The routine
* takes the user's name, instance, and realm, the client's
* timestamp, the number of tickets, the user's key version
* number and the ciphertext containing the tickets themselves.
* It constructs a packet and returns a pointer to it.
*
* Notes: The packet returned by this routine is static. Thus, if you
* intend to keep the result beyond the next call to this routine, you
* must copy it elsewhere.
*
* The packet is built in the following format:
*
* variable
* type or constant data
* ---- ----------- ----
*
* unsigned char KRB_PROT_VERSION protocol version number
*
* unsigned char AUTH_MSG_KDC_REPLY protocol message type
*
* [least significant HOST_BYTE_ORDER sender's (server's) byte
* bit of above field] order
*
* string pname principal's name
*
* string pinst principal's instance
*
* string prealm principal's realm
*
* unsigned long time_ws client's timestamp
*
* unsigned char n number of tickets
*
* unsigned long x_date expiration date
*
* unsigned char kvno master key version
*
* short w_1 cipher length
*
* --- cipher->dat cipher data
*/
KTEXT
create_auth_reply(pname, pinst, prealm, time_ws, n, x_date, kvno, cipher)
char *pname; /* Principal's name */
char *pinst; /* Principal's instance */
char *prealm; /* Principal's authentication domain */
long time_ws; /* Workstation time */
int n; /* Number of tickets */
unsigned long x_date; /* Principal's expiration date */
int kvno; /* Principal's key version number */
KTEXT cipher; /* Cipher text with tickets and
* session keys */
{
static KTEXT_ST pkt_st;
KTEXT pkt = &pkt_st;
unsigned char *p;
size_t pnamelen, pinstlen, prealmlen;
/* Create fixed part of packet */
p = pkt->dat;
/* This is really crusty. */
if (n != 0)
*p++ = 3;
else
*p++ = KRB_PROT_VERSION;
*p++ = AUTH_MSG_KDC_REPLY; /* always big-endian */
/* Make sure the response will actually fit into its buffer. */
pnamelen = strlen(pname) + 1;
pinstlen = strlen(pinst) + 1;
prealmlen = strlen(prealm) + 1;
if (sizeof(pkt->dat) < (1 + 1 + pnamelen + pinstlen + prealmlen
+ 4 + 1 + 4 + 1 + 2 + cipher->length)
|| cipher->length > 65535 || cipher->length < 0) {
pkt->length = 0;
return NULL;
}
/* Add the basic info */
memcpy(p, pname, pnamelen);
p += pnamelen;
memcpy(p, pinst, pinstlen);
p += pinstlen;
memcpy(p, prealm, prealmlen);
p += prealmlen;
/* Workstation timestamp */
KRB4_PUT32(p, time_ws);
*p++ = n;
/* Expiration date */
KRB4_PUT32(p, x_date);
/* Now send the ciphertext and info to help decode it */
*p++ = kvno;
KRB4_PUT16(p, cipher->length);
memcpy(p, cipher->dat, (size_t)cipher->length);
p += cipher->length;
/* And return the packet */
pkt->length = p - pkt->dat;
return pkt;
}
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