/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */


#include <string.h>

#include "k5-int.h"
#include <kadm5/admin.h>
#include <client_internal.h>
#include "auth_con.h"
#include <locale.h>


krb5_error_code
krb5int_mk_chpw_req(
	krb5_context context,
	krb5_auth_context auth_context,
	krb5_data *ap_req,
	char *passwd,
	krb5_data *packet)
{
    krb5_error_code ret = 0;
    krb5_data clearpw;
    krb5_data cipherpw;
    krb5_replay_data replay;
    char *ptr;

    cipherpw.data = NULL;

    if ((ret = krb5_auth_con_setflags(context, auth_context,
				      KRB5_AUTH_CONTEXT_DO_SEQUENCE)))
	  goto cleanup;

    clearpw.length = strlen(passwd);
    clearpw.data = passwd;

    if ((ret = krb5_mk_priv(context, auth_context,
			    &clearpw, &cipherpw, &replay)))
      goto cleanup;

    packet->length = 6 + ap_req->length + cipherpw.length;
    packet->data = (char *) malloc(packet->length);
    if (packet->data == NULL)
	{
	    ret = ENOMEM;
	    goto cleanup;
	}
    ptr = packet->data;

    /* length */

    *ptr++ = (packet->length>> 8) & 0xff;
    *ptr++ = packet->length & 0xff;

    /* version == 0x0001 big-endian
     * NOTE: when MS and MIT start supporting the latest
     *	version of the passwd change protocol (v2),
     *	this value will change to 2.
     */
    *ptr++ = 0;
    *ptr++ = 1;

    /* ap_req length, big-endian */

    *ptr++ = (ap_req->length>>8) & 0xff;
    *ptr++ = ap_req->length & 0xff;

    /* ap-req data */

    memcpy(ptr, ap_req->data, ap_req->length);
    ptr += ap_req->length;

    /* krb-priv of password */

    memcpy(ptr, cipherpw.data, cipherpw.length);

cleanup:
    if(cipherpw.data != NULL)  /* allocated by krb5_mk_priv */
      free(cipherpw.data);

    return(ret);
}

krb5_error_code
krb5int_rd_chpw_rep(krb5_context context, krb5_auth_context auth_context, krb5_data *packet, int *result_code, krb5_data *result_data)
{
    char *ptr;
    int plen, vno;
    krb5_data ap_rep;
    krb5_ap_rep_enc_part *ap_rep_enc;
    krb5_error_code ret;
    krb5_data cipherresult;
    krb5_data clearresult;
    krb5_error *krberror;
    krb5_replay_data replay;
    krb5_keyblock *tmp;
    int local_result_code;

    if (packet->length < 4)
	/* either this, or the server is printing bad messages,
	   or the caller passed in garbage */
	return(KRB5KRB_AP_ERR_MODIFIED);

    ptr = packet->data;

    /* verify length */

    plen = (*ptr++ & 0xff);
    plen = (plen<<8) | (*ptr++ & 0xff);

    if (plen != packet->length)
	{
		/*
		 * MS KDCs *may* send back a KRB_ERROR.  Although
		 * not 100% correct via RFC3244, it's something
		 * we can workaround here.
		 */
		if (krb5_is_krb_error(packet)) {

			if ((ret = krb5_rd_error(context, packet, &krberror)))
			return(ret);

			if (krberror->e_data.data  == NULL) {
				ret = ERROR_TABLE_BASE_krb5 + (krb5_error_code) krberror->error;
				krb5_free_error(context, krberror);
				return (ret);
			}
		}
		else
		{
			return(KRB5KRB_AP_ERR_MODIFIED);
		}
	}


    /* verify version number */

    vno = (*ptr++ & 0xff);
    vno = (vno<<8) | (*ptr++ & 0xff);

	/*
	 * when the servers update to v2 of the protocol,
	 * "2" will be a valid version number here
	 */
	if (vno != 1 && vno != 2)
		return (KRB5KDC_ERR_BAD_PVNO);

    /* read, check ap-rep length */

    ap_rep.length = (*ptr++ & 0xff);
    ap_rep.length = (ap_rep.length<<8) | (*ptr++ & 0xff);

    if (ptr + ap_rep.length >= packet->data + packet->length)
	return(KRB5KRB_AP_ERR_MODIFIED);

    if (ap_rep.length) {
	/* verify ap_rep */
	ap_rep.data = ptr;
	ptr += ap_rep.length;

	/*
	 * Save send_subkey to later smash recv_subkey.
	 */
	ret = krb5_auth_con_getsendsubkey(context, auth_context, &tmp);
	if (ret)
	    return ret;

	ret = krb5_rd_rep(context, auth_context, &ap_rep, &ap_rep_enc);
	if (ret) {
	    krb5_free_keyblock(context, tmp);
	    return(ret);
	}

	krb5_free_ap_rep_enc_part(context, ap_rep_enc);

	/* extract and decrypt the result */

	cipherresult.data = ptr;
	cipherresult.length = (packet->data + packet->length) - ptr;

	/*
	 * Smash recv_subkey to be send_subkey, per spec.
	 */
	ret = krb5_auth_con_setrecvsubkey(context, auth_context, tmp);
	krb5_free_keyblock(context, tmp);
	if (ret)
	    return ret;

	ret = krb5_rd_priv(context, auth_context, &cipherresult, &clearresult,
			   &replay);

	if (ret)
	    return(ret);
    } else {
	cipherresult.data = ptr;
	cipherresult.length = (packet->data + packet->length) - ptr;

	if ((ret = krb5_rd_error(context, &cipherresult, &krberror)))
	    return(ret);

	clearresult = krberror->e_data;
    }

    if (clearresult.length < 2) {
	ret = KRB5KRB_AP_ERR_MODIFIED;
	goto cleanup;
    }

    ptr = clearresult.data;

    local_result_code = (*ptr++ & 0xff);
    local_result_code = (local_result_code<<8) | (*ptr++ & 0xff);

	if (result_code)
		*result_code = local_result_code;

	/*
	 * Make sure the result code is in range for this
	 * protocol.
	 */
    if ((local_result_code < KRB5_KPASSWD_SUCCESS) ||
	 (local_result_code > KRB5_KPASSWD_ETYPE_NOSUPP)) {
	ret = KRB5KRB_AP_ERR_MODIFIED;
	goto cleanup;
    }

    /* all success replies should be authenticated/encrypted */

    if ((ap_rep.length == 0) && (local_result_code == KRB5_KPASSWD_SUCCESS)) {
	ret = KRB5KRB_AP_ERR_MODIFIED;
	goto cleanup;
    }

    result_data->length = (clearresult.data + clearresult.length) - ptr;

    if (result_data->length) {
	result_data->data = (char *) malloc(result_data->length);
	if (result_data->data == NULL) {
	    ret = ENOMEM;
	    goto cleanup;
	}
	memcpy(result_data->data, ptr, result_data->length);
    } else {
	result_data->data = NULL;
    }

    ret = 0;

cleanup:
    if (ap_rep.length) {
	krb5_xfree(clearresult.data);
    } else {
	krb5_free_error(context, krberror);
    }

    return(ret);
}