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/*
* lib/krb4/prot_common.c
*
* Copyright 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.
*
* Contains some common code used by multiple encoders/decoders.
*/
#include "krb.h"
#include "prot.h"
#include <string.h>
/*
* encode_naminstrlm
*
* Takes input string triplet of a principal, encodes into PKT.
* Assumes that input strings are properly terminated. If CHKLEN is
* non-zero, validate input string lengths against their respective
* limits. The pointer P is the address of the moving pointer used by
* the caller, and is updated here.
*
* Returns zero on success, non-zero on failure.
*
* PKT->LENGTH is NOT updated. The caller must update it.
*/
int KRB5_CALLCONV
krb4prot_encode_naminstrlm(char *name, char *inst, char *realm,
int chklen, /* check input str len? */
KTEXT pkt, /* buffer to encode into */
unsigned char **p /* moving pointer */)
{
size_t namelen, instlen, realmlen;
namelen = strlen(name) + 1;
instlen = strlen(inst) + 1;
realmlen = strlen(realm) + 1;
if (chklen && (namelen > ANAME_SZ || instlen > INST_SZ
|| realmlen > REALM_SZ))
return KRB4PROT_ERR_OVERRUN;
if (*p - pkt->dat < namelen + instlen + realmlen)
return KRB4PROT_ERR_OVERRUN;
memcpy(*p, name, namelen);
*p += namelen;
memcpy(*p, inst, instlen);
*p += namelen;
memcpy(*p, realm, realmlen);
*p += namelen;
return KRB4PROT_OK;
}
/*
* decode_naminstrlm
*
* Grabs a string triplet corresponding to a principal. The input
* buffer PKT should have its length properly set. The pointer P is
* the address of the moving pointer used by the caller, and will be
* updated. If any input pointer is NULL, merely skip the string.
*
* The output strings NAME, INST, and REALM are assumed to be of the
* correct sizes (ANAME_SZ, INST_SZ, REALM_SZ).
*
* Returns 0 on success, non-zero on failure.
*/
int KRB5_CALLCONV
krb4prot_decode_naminstrlm(KTEXT pkt, /* buffer to decode from */
unsigned char **p, /* moving pointer */
char *name, char *inst, char *realm)
{
int len;
#define PKT_REMAIN (pkt->length - (*p - pkt->dat))
if (PKT_REMAIN <= 0)
return KRB4PROT_ERR_UNDERRUN;
len = krb4int_strnlen((char *)*p, PKT_REMAIN) + 1;
if (len == 0 || len > ANAME_SZ)
return KRB4PROT_ERR_OVERRUN;
if (name != NULL)
memcpy(name, *p, (size_t)len);
*p += len;
if (PKT_REMAIN <= 0)
return KRB4PROT_ERR_UNDERRUN;
len = krb4int_strnlen((char *)*p, PKT_REMAIN) + 1;
if (len <= 0 || len > INST_SZ)
return KRB4PROT_ERR_OVERRUN;
if (name != NULL)
memcpy(inst, *p, (size_t)len);
*p += len;
if (PKT_REMAIN <= 0)
return KRB4PROT_ERR_UNDERRUN;
len = krb4int_strnlen((char *)*p, PKT_REMAIN) + 1;
if (len <= 0 || len > REALM_SZ)
return KRB4PROT_ERR_OVERRUN;
if (realm != NULL)
memcpy(realm, *p, (size_t)len);
*p += len;
return KRB4PROT_OK;
#undef PKT_REMAIN
}
int KRB5_CALLCONV
krb4prot_decode_header(KTEXT pkt,
int *pver, int *msgtype, int *le)
{
unsigned char *p;
p = pkt->dat;
if (pkt->length < 2)
return KRB4PROT_ERR_UNDERRUN;
*pver = *p++;
*msgtype = *p++;
*le = *msgtype & 1;
*msgtype &= ~1;
return KRB4PROT_OK;
}
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