/*
 * Copyright (c) 1997 - 2002 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>

krb5_error_code
_krb5_mk_req_internal(krb5_context context,
		      krb5_auth_context *auth_context,
		      const krb5_flags ap_req_options,
		      krb5_data *in_data,
		      krb5_creds *in_creds,
		      krb5_data *outbuf,
		      krb5_key_usage checksum_usage,
		      krb5_key_usage encrypt_usage)
{
    krb5_error_code ret;
    krb5_data authenticator;
    Checksum c;
    Checksum *c_opt;
    krb5_auth_context ac;

    if(auth_context) {
	if(*auth_context == NULL)
	    ret = krb5_auth_con_init(context, auth_context);
	else
	    ret = 0;
	ac = *auth_context;
    } else
	ret = krb5_auth_con_init(context, &ac);
    if(ret)
	return ret;

    if(ac->local_subkey == NULL && (ap_req_options & AP_OPTS_USE_SUBKEY)) {
	ret = krb5_auth_con_generatelocalsubkey(context,
						ac,
						&in_creds->session);
	if(ret)
	    goto out;
    }

    krb5_free_keyblock(context, ac->keyblock);
    ret = krb5_copy_keyblock(context, &in_creds->session, &ac->keyblock);
    if (ret)
	goto out;

    /* it's unclear what type of checksum we can use.  try the best one, except:
     * a) if it's configured differently for the current realm, or
     * b) if the session key is des-cbc-crc
     */

    if (in_data) {
	if(ac->keyblock->keytype == ETYPE_DES_CBC_CRC) {
	    /* this is to make DCE secd (and older MIT kdcs?) happy */
	    ret = krb5_create_checksum(context,
				       NULL,
				       0,
				       CKSUMTYPE_RSA_MD4,
				       in_data->data,
				       in_data->length,
				       &c);
	} else if(ac->keyblock->keytype == ETYPE_ARCFOUR_HMAC_MD5 ||
		  ac->keyblock->keytype == ETYPE_ARCFOUR_HMAC_MD5_56 ||
		  ac->keyblock->keytype == ETYPE_DES_CBC_MD4 ||
		  ac->keyblock->keytype == ETYPE_DES_CBC_MD5) {
	    /* this is to make MS kdc happy */
	    ret = krb5_create_checksum(context,
				       NULL,
				       0,
				       CKSUMTYPE_RSA_MD5,
				       in_data->data,
				       in_data->length,
				       &c);
	} else {
	    krb5_crypto crypto;

	    ret = krb5_crypto_init(context, ac->keyblock, 0, &crypto);
	    if (ret)
		goto out;
	    ret = krb5_create_checksum(context,
				       crypto,
				       checksum_usage,
				       0,
				       in_data->data,
				       in_data->length,
				       &c);
	    krb5_crypto_destroy(context, crypto);
	}
	c_opt = &c;
    } else {
	c_opt = NULL;
    }

    if (ret)
	goto out;

    ret = krb5_build_authenticator (context,
				    ac,
				    ac->keyblock->keytype,
				    in_creds,
				    c_opt,
				    NULL,
				    &authenticator,
				    encrypt_usage);
    if (c_opt)
	free_Checksum (c_opt);
    if (ret)
	goto out;

    ret = krb5_build_ap_req (context, ac->keyblock->keytype,
			     in_creds, ap_req_options, authenticator, outbuf);
out:
    if(auth_context == NULL)
	krb5_auth_con_free(context, ac);
    return ret;
}

krb5_error_code KRB5_LIB_FUNCTION
krb5_mk_req_extended(krb5_context context,
		     krb5_auth_context *auth_context,
		     const krb5_flags ap_req_options,
		     krb5_data *in_data,
		     krb5_creds *in_creds,
		     krb5_data *outbuf)
{
    return _krb5_mk_req_internal (context,
				 auth_context,
				 ap_req_options,
				 in_data,
				 in_creds,
				 outbuf,
				 KRB5_KU_AP_REQ_AUTH_CKSUM,
				 KRB5_KU_AP_REQ_AUTH);
}
