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/*
* lib/krb4/decomp_tkt.c
*
* Copyright 1985, 1986, 1987, 1988, 2000, 2001 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 "des.h"
#include "krb.h"
#include "prot.h"
#include <string.h>
#include <krb5.h>
#include "krb54proto.h"
#ifdef KRB_CRYPT_DEBUG
extern int krb_debug;
#endif
static int dcmp_tkt_int (KTEXT tkt, unsigned char *flags,
char *pname, char *pinstance, char *prealm,
unsigned KRB4_32 *paddress, C_Block session,
int *life, unsigned KRB4_32 *time_sec,
char *sname, char *sinstance, C_Block key,
Key_schedule key_s, krb5_keyblock *k5key);
/*
* This routine takes a ticket and pointers to the variables that
* should be filled in based on the information in the ticket. It
#ifndef NOENCRYPTION
* decrypts the ticket using the given key, and
#endif
* fills in values for its arguments.
*
* Note: if the client realm field in the ticket is the null string,
* then the "prealm" variable is filled in with the local realm (as
* defined by KRB_REALM).
*
* If the ticket byte order is different than the host's byte order
* (as indicated by the byte order bit of the "flags" field), then
* the KDC timestamp "time_sec" is byte-swapped. The other fields
* potentially affected by byte order, "paddress" and "session" are
* not byte-swapped.
*
* The routine returns KFAILURE if any of the "pname", "pinstance",
* or "prealm" fields is too big, otherwise it returns KSUCCESS.
*
* The corresponding routine to generate tickets is create_ticket.
* When changes are made to this routine, the corresponding changes
* should also be made to that file.
*
* See create_ticket.c for the format of the ticket packet.
*/
int
decomp_ticket(tkt, flags, pname, pinstance, prealm, paddress, session,
life, time_sec, sname, sinstance, key, key_s)
KTEXT tkt; /* The ticket to be decoded */
unsigned char *flags; /* Kerberos ticket flags */
char *pname; /* Authentication name */
char *pinstance; /* Principal's instance */
char *prealm; /* Principal's authentication domain */
unsigned KRB4_32 *paddress; /* Net address of entity
* requesting ticket */
C_Block session; /* Session key inserted in ticket */
int *life; /* Lifetime of the ticket */
unsigned KRB4_32 *time_sec; /* Issue time and date */
char *sname; /* Service name */
char *sinstance; /* Service instance */
C_Block key; /* Service's secret key
* (to decrypt the ticket) */
Key_schedule key_s; /* The precomputed key schedule */
{
return
dcmp_tkt_int(tkt, flags, pname, pinstance, prealm,
paddress, session, life, time_sec, sname, sinstance,
key, key_s, NULL);
}
int
decomp_tkt_krb5(tkt, flags, pname, pinstance, prealm, paddress, session,
life, time_sec, sname, sinstance, k5key)
KTEXT tkt; /* The ticket to be decoded */
unsigned char *flags; /* Kerberos ticket flags */
char *pname; /* Authentication name */
char *pinstance; /* Principal's instance */
char *prealm; /* Principal's authentication domain */
unsigned KRB4_32 *paddress; /* Net address of entity
* requesting ticket */
C_Block session; /* Session key inserted in ticket */
int *life; /* Lifetime of the ticket */
unsigned KRB4_32 *time_sec; /* Issue time and date */
char *sname; /* Service name */
char *sinstance; /* Service instance */
krb5_keyblock *k5key; /* krb5 keyblock of service */
{
C_Block key; /* placeholder; doesn't get used */
Key_schedule key_s; /* placeholder; doesn't get used */
return
dcmp_tkt_int(tkt, flags, pname, pinstance, prealm, paddress, session,
life, time_sec, sname, sinstance, key, key_s, k5key);
}
static int
dcmp_tkt_int(tkt, flags, pname, pinstance, prealm, paddress, session,
life, time_sec, sname, sinstance, key, key_s, k5key)
KTEXT tkt; /* The ticket to be decoded */
unsigned char *flags; /* Kerberos ticket flags */
char *pname; /* Authentication name */
char *pinstance; /* Principal's instance */
char *prealm; /* Principal's authentication domain */
unsigned KRB4_32 *paddress; /* Net address of entity
* requesting ticket */
C_Block session; /* Session key inserted in ticket */
int *life; /* Lifetime of the ticket */
unsigned KRB4_32 *time_sec; /* Issue time and date */
char *sname; /* Service name */
char *sinstance; /* Service instance */
C_Block key; /* Service's secret key
* (to decrypt the ticket) */
Key_schedule key_s; /* The precomputed key schedule */
krb5_keyblock *k5key; /* krb5 keyblock of service */
{
int tkt_le; /* little-endian ticket? */
unsigned char *ptr = tkt->dat;
int kret, len;
struct in_addr paddr;
/* Be really paranoid. */
if (sizeof(paddr.s_addr) != 4)
return KFAILURE;
#ifndef NOENCRYPTION
/* Do the decryption */
#ifdef KRB_CRYPT_DEBUG
if (krb_debug) {
FILE *fp;
char *keybuf[BUFSIZ]; /* Avoid secret stuff in stdio buffers */
fp = fopen("/kerberos/tkt.des", "wb");
setbuf(fp, keybuf);
fwrite(tkt->dat, 1, tkt->length, fp);
fclose(fp);
memset(keybuf, 0, sizeof(keybuf)); /* Clear the buffer */
}
#endif
if (k5key != NULL) {
/* block locals */
krb5_enc_data in;
krb5_data out;
krb5_error_code ret;
in.enctype = k5key->enctype;
in.kvno = 0;
in.ciphertext.length = tkt->length;
in.ciphertext.data = (char *)tkt->dat;
out.length = tkt->length;
out.data = malloc((size_t)tkt->length);
if (out.data == NULL)
return KFAILURE; /* XXX maybe ENOMEM? */
/* XXX note the following assumes that context arg isn't used */
ret =
krb5_c_decrypt(NULL, k5key,
KRB5_KEYUSAGE_KDC_REP_TICKET, NULL, &in, &out);
if (ret) {
free(out.data);
return KFAILURE;
} else {
memcpy(tkt->dat, out.data, out.length);
memset(out.data, 0, out.length);
free(out.data);
}
} else {
pcbc_encrypt((C_Block *)tkt->dat, (C_Block *)tkt->dat,
(long)tkt->length, key_s, (C_Block *)key, 0);
}
#endif /* ! NOENCRYPTION */
#ifdef KRB_CRYPT_DEBUG
if (krb_debug) {
FILE *fp;
char *keybuf[BUFSIZ]; /* Avoid secret stuff in stdio buffers */
fp = fopen("/kerberos/tkt.clear", "wb");
setbuf(fp, keybuf);
fwrite(tkt->dat, 1, tkt->length, fp);
fclose(fp);
memset(keybuf, 0, sizeof(keybuf)); /* Clear the buffer */
}
#endif
#define TKT_REMAIN (tkt->length - (ptr - tkt->dat))
kret = KFAILURE;
if (TKT_REMAIN < 1)
goto cleanup;
*flags = *ptr++;
tkt_le = (*flags >> K_FLAG_ORDER) & 1;
len = krb4int_strnlen((char *)ptr, TKT_REMAIN) + 1;
if (len <= 0 || len > ANAME_SZ)
goto cleanup;
memcpy(pname, ptr, (size_t)len);
ptr += len;
len = krb4int_strnlen((char *)ptr, TKT_REMAIN) + 1;
if (len <= 0 || len > INST_SZ)
goto cleanup;
memcpy(pinstance, ptr, (size_t)len);
ptr += len;
len = krb4int_strnlen((char *)ptr, TKT_REMAIN) + 1;
if (len <= 0 || len > REALM_SZ)
goto cleanup;
memcpy(prealm, ptr, (size_t)len);
ptr += len;
/* temporary hack until realms are dealt with properly */
if (*prealm == '\0')
strcpy(prealm, KRB_REALM);
/*
* Ensure there's enough remaining in the ticket to get the
* fixed-size stuff.
*/
if (TKT_REMAIN < 4 + 8 + 1 + 4)
goto cleanup;
memcpy(&paddr.s_addr, ptr, sizeof(paddr.s_addr));
ptr += sizeof(paddr.s_addr);
*paddress = paddr.s_addr;
memcpy(session, ptr, 8); /* session key */
memset(ptr, 0, 8);
ptr += 8;
#ifdef notdef /* DONT SWAP SESSION KEY spm 10/22/86 */
if (tkt_swap_bytes)
swap_C_Block(session);
#endif
*life = *ptr++;
KRB4_GET32(*time_sec, ptr, tkt_le);
len = krb4int_strnlen((char *)ptr, TKT_REMAIN) + 1;
if (len <= 0 || len > SNAME_SZ)
goto cleanup;
memcpy(sname, ptr, (size_t)len);
ptr += len;
len = krb4int_strnlen((char *)ptr, TKT_REMAIN) + 1;
if (len <= 0 || len > INST_SZ)
goto cleanup;
memcpy(sinstance, ptr, (size_t)len);
ptr += len;
kret = KSUCCESS;
#ifdef KRB_CRYPT_DEBUG
if (krb_debug) {
krb_log("service=%s.%s len(sname)=%d, len(sinstance)=%d",
sname, sinstance, strlen(sname), strlen(sinstance));
krb_log("ptr - tkt->dat=%d",(char *)ptr - (char *)tkt->dat);
}
#endif
cleanup:
if (kret != KSUCCESS) {
memset(session, 0, sizeof(session));
memset(tkt->dat, 0, (size_t)tkt->length);
return kret;
}
return KSUCCESS;
}
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