util_seqnum.c   [plain text]

/*
  * Copyright2001 by the Massachusetts Institute of Technology.
 * Copyright 1993 by OpenVision Technologies, Inc.
 * 
 * Permission to use, copy, modify, distribute, and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appears in all copies and
 * that both that copyright notice and this permission notice appear in
 * supporting documentation, and that the name of OpenVision not be used
 * in advertising or publicity pertaining to distribution of the software
 * without specific, written prior permission. OpenVision makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 * 
 * OPENVISION DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
 * EVENT SHALL OPENVISION BE LIABLE FOR ANY SPECIAL, INDIRECT OR
 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF
 * USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
 * OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
 * PERFORMANCE OF THIS SOFTWARE.
 */

#include "gssapiP_krb5.h"
#include "k5-int.h"

/*
 * $Id: util_seqnum.c,v 1.13 2002/11/15 16:12:20 epeisach Exp $
 */

krb5_error_code
kg_make_seq_num(context, key, direction, seqnum, cksum, buf)
     krb5_context context;
     krb5_keyblock *key;
     int direction;
     krb5_ui_4 seqnum;
     unsigned char *cksum;
     unsigned char *buf;
{
   unsigned char plain[8];

   plain[4] = direction;
   plain[5] = direction;
   plain[6] = direction;
   plain[7] = direction;
   if (key->enctype == ENCTYPE_ARCFOUR_HMAC ) {
     /* Yes, Microsoft used big-endian sequence number.*/
     plain[0] = (seqnum>>24) & 0xff;
     plain[1] = (seqnum>>16) & 0xff;
     plain[2] = (seqnum>>8) & 0xff;
     plain[3] = seqnum & 0xff;
     return kg_arcfour_docrypt (key, 0, 
				cksum, 8,
				&plain[0], 8,
				buf);
     
   }
     
   plain[0] = (unsigned char) (seqnum&0xff);
   plain[1] = (unsigned char) ((seqnum>>8)&0xff);
   plain[2] = (unsigned char) ((seqnum>>16)&0xff);
   plain[3] = (unsigned char) ((seqnum>>24)&0xff);

   return(kg_encrypt(context, key, KG_USAGE_SEQ, cksum, plain, buf, 8));
}

krb5_error_code kg_get_seq_num(context, key, cksum, buf, direction, seqnum)
     krb5_context context;
     krb5_keyblock *key;
     unsigned char *cksum;
     unsigned char *buf;
     int *direction;
     krb5_ui_4 *seqnum;
{
   krb5_error_code code;
   unsigned char plain[8];

   if (key->enctype == ENCTYPE_ARCFOUR_HMAC) {
     code = kg_arcfour_docrypt (key, 0,
				cksum, 8,
				buf, 8,
				plain);
   } else {
     code = kg_decrypt(context, key, KG_USAGE_SEQ, cksum, buf, plain, 8);
   }
   if (code)
      return(code);

   if ((plain[4] != plain[5]) ||
       (plain[4] != plain[6]) ||
       (plain[4] != plain[7]))
      return((krb5_error_code) KG_BAD_SEQ);

   *direction = plain[4];
   if (key->enctype == ENCTYPE_ARCFOUR_HMAC) {
     *seqnum = (plain[3]|(plain[2]<<8) | (plain[1]<<16)| (plain[0]<<24));
   } else {
     *seqnum = ((plain[0]) |
	      (plain[1]<<8) |
	      (plain[2]<<16) |
	      (plain[3]<<24));
   }

   return(0);
}