/*
 * Copyright (c) 1997 - 2001 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 <krb5_locl.h>

RCSID("$Id: rd_priv.c,v 1.29 2001/06/18 02:46:15 assar Exp $");

krb5_error_code
krb5_rd_priv(krb5_context context,
	     krb5_auth_context auth_context,
	     const krb5_data *inbuf,
	     krb5_data *outbuf,
	     /*krb5_replay_data*/ void *outdata)
{
  krb5_error_code ret;
  KRB_PRIV priv;
  EncKrbPrivPart part;
  size_t len;
  krb5_data plain;
  krb5_keyblock *key;
  krb5_crypto crypto;

  memset(&priv, 0, sizeof(priv));
  ret = decode_KRB_PRIV (inbuf->data, inbuf->length, &priv, &len);
  if (ret) 
      goto failure;
  if (priv.pvno != 5) {
      krb5_clear_error_string (context);
      ret = KRB5KRB_AP_ERR_BADVERSION;
      goto failure;
  }
  if (priv.msg_type != krb_priv) {
      krb5_clear_error_string (context);
      ret = KRB5KRB_AP_ERR_MSG_TYPE;
      goto failure;
  }

  if (auth_context->remote_subkey)
      key = auth_context->remote_subkey;
  else if (auth_context->local_subkey)
      key = auth_context->local_subkey;
  else
      key = auth_context->keyblock;

  ret = krb5_crypto_init(context, key, 0, &crypto);
  if (ret)
      goto failure;
  ret = krb5_decrypt_EncryptedData(context,
				   crypto,
				   KRB5_KU_KRB_PRIV,
				   &priv.enc_part,
				   &plain);
  krb5_crypto_destroy(context, crypto);
  if (ret) 
      goto failure;

  ret = decode_EncKrbPrivPart (plain.data, plain.length, &part, &len);
  krb5_data_free (&plain);
  if (ret) 
      goto failure;
  
  /* check sender address */

  if (part.s_address
      && auth_context->remote_address
      && !krb5_address_compare (context,
				auth_context->remote_address,
				part.s_address)) {
      krb5_clear_error_string (context);
      ret = KRB5KRB_AP_ERR_BADADDR;
      goto failure_part;
  }

  /* check receiver address */

  if (part.r_address
      && auth_context->local_address
      && !krb5_address_compare (context,
				auth_context->local_address,
				part.r_address)) {
      krb5_clear_error_string (context);
      ret = KRB5KRB_AP_ERR_BADADDR;
      goto failure_part;
  }

  /* check timestamp */
  if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_TIME) {
      krb5_timestamp sec;

      krb5_timeofday (context, &sec);
      if (part.timestamp == NULL ||
	  part.usec      == NULL ||
	  abs(*part.timestamp - sec) > context->max_skew) {
	  krb5_clear_error_string (context);
	  ret = KRB5KRB_AP_ERR_SKEW;
	  goto failure_part;
      }
  }

  /* XXX - check replay cache */

  /* check sequence number. since MIT krb5 cannot generate a sequence
     number of zero but instead generates no sequence number, we accept that
  */

  if (auth_context->flags & KRB5_AUTH_CONTEXT_DO_SEQUENCE) {
      if ((part.seq_number == NULL
	   && auth_context->remote_seqnumber != 0)
	  || (part.seq_number != NULL
	      && *part.seq_number != auth_context->remote_seqnumber)) {
	  krb5_clear_error_string (context);
	  ret = KRB5KRB_AP_ERR_BADORDER;
	  goto failure_part;
      }
      auth_context->remote_seqnumber++;
  }

  ret = krb5_data_copy (outbuf, part.user_data.data, part.user_data.length);
  if (ret)
      goto failure_part;

  free_EncKrbPrivPart (&part);
  free_KRB_PRIV (&priv);
  return 0;

failure_part:
  free_EncKrbPrivPart (&part);

failure:
  free_KRB_PRIV (&priv);
  return ret;
}