/*
 * Copyright 1997,1998 Niels Provos <provos@physnet.uni-hamburg.de>
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by Niels Provos.
 * 4. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */
/*
 * handle_identity_response:
 * receive a IDENTITY_RESPONSE packet; return -1 on failure, 0 on success
 *
 */

#ifndef lint
static char rcsid[] = "$Id: handle_identity_response.c,v 1.6 1998/05/18 21:25:25 provos Exp $";
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <sys/time.h>
#include "config.h"
#include "photuris.h"
#include "packets.h"
#include "state.h"
#include "cookie.h"
#include "buffer.h"
#include "packet.h"
#include "schedule.h"
#include "encrypt.h"
#include "identity.h"
#include "attributes.h"
#include "secrets.h"
#include "scheme.h"
#include "errlog.h"
#include "spi.h"
#ifdef IPSEC
#include "kernel.h"
#endif
#ifdef DEBUG
#include "packet.h"
#endif

int
handle_identity_response(u_char *packet, int size, char *address,
			 char *local_address)
{
        struct packet_sub parts[] = {
	     { "IDChoice", FLD_ATTRIB, FMD_ATT_ONE, 0, },
	     { "Identity", FLD_VARPRE, 0, 0, },
	     { "Verification", FLD_VARPRE, 0, 0, },
	     { "Attributes", FLD_ATTRIB, FMD_ATT_FILL, 0, },
	     { NULL }
	};

        struct packet id_msg = {
	     "Identity Response",
	     IDENTITY_MESSAGE_MIN, 0, parts
	};

	struct identity_message *header;
	struct stateob *st;
	struct spiob *spi;
	u_int8_t *attributes;
	u_int16_t i, attribsize, tmp;
	u_int8_t signature[22];  /* XXX - constant */

	if (size < IDENTITY_MESSAGE_MIN)
	     return -1;	/* packet too small  */

	header = (struct identity_message *) packet;

	st = state_find_cookies(address, header->icookie, header->rcookie);
	if (st == NULL)
	     return -1;     /* Silently discard */

	if (st->phase != IDENTITY_REQUEST)
	     return 0;      /* We don't want this packet */

	/* Decrypt message */
	tmp = size - IDENTITY_MESSAGE_MIN;
	if (packet_decrypt(st, IDENTITY_MESSAGE_CHOICE(header), &tmp) == -1) {
	     log_error(0, "packet_decrypt() in handle_identity_response()");
	     goto verification_failed;
	}

#ifdef DEBUG
	printf("Identity Response (after decryption):\n");
	packet_dump((u_int8_t *)header, size, 0);
#endif
	/* Verify message structure */
	if (packet_check(packet, size - packet[size-1], &id_msg) == -1) {
	     log_error(0, "bad packet structure in handle_identity_response()");
	     return -1;
	}

	i = get_identity_verification_size(st, IDENTITY_MESSAGE_CHOICE(header));
	if (!i || i != parts[2].size || i >sizeof(signature)) {
	     log_error(0, "verification size mismatch in handle_identity_response()");
	     goto verification_failed;
	}
	bcopy(parts[2].where, signature, parts[2].size);
	
	attributes = parts[3].where;
	attribsize = parts[3].size;

	if (!isattribsubset(st->oSPIoattrib,st->oSPIoattribsize,
			    attributes, attribsize)) {
	     log_error(0, "attributes are not a subset in handle_identity_response()");
	     return 0;
	}


	/* Fill the state object */
	if((st->uSPIidentver = calloc(i, sizeof(u_int8_t))) == NULL) { 
	     log_error(1, "calloc() in handle_identity_response()"); 
	     goto verification_failed;
	}
	bcopy(signature, st->uSPIidentver, i);
	st->uSPIidentversize = i;

	if((st->uSPIidentchoice = calloc(parts[0].size, sizeof(u_int8_t))) == NULL) {
	     log_error(1, "calloc() in handle_identity_response()");
	     goto verification_failed;
	}
	bcopy(parts[0].where, st->uSPIidentchoice, parts[0].size);
	st->uSPIidentchoicesize = parts[0].size;

	if((st->uSPIident = calloc(parts[1].size, sizeof(u_int8_t))) == NULL) {
	     log_error(1, "calloc() in handle_identity_response()"); 
	     goto verification_failed;
	}
	bcopy(parts[1].where, st->uSPIident, parts[1].size);
	
	if((st->uSPIattrib = calloc(attribsize, sizeof(u_int8_t))) == NULL) {
	     log_error(1, "calloc() in handle_identity_response()");
	     goto verification_failed;
	}
	bcopy(attributes, st->uSPIattrib, attribsize);
	st->uSPIattribsize = attribsize;

	if (get_secrets(st, ID_REMOTE) == -1) {
	     log_error(0, "get_secrets() in in handle_identity_response()");
	     goto verification_failed;
	}

	if (!verify_identity_verification(st, signature, packet, size)) {
	     /* 
	      * Clean up everything used from this packet 
	      */
	     free(st->uSPIidentchoice);
	     st->uSPIidentchoice = NULL; st->uSPIidentchoicesize = 0;
	     free(st->uSPIidentver);
	     st->uSPIidentver = NULL; st->uSPIidentversize = 0;
	     free(st->uSPIattrib);
	     st->uSPIattrib = NULL; st->uSPIattribsize = 0;
	     free(st->uSPIident);
	     st->uSPIident = NULL;

	     /* Clean up secrets */
	     free(st->uSPIsecret);
	     st->uSPIsecret = NULL; st->uSPIsecretsize = 0;
	verification_failed:
	     log_error(0, "verification failed in handle_identity_response()");
	     packet_size = PACKET_BUFFER_SIZE;
	     photuris_error_message(st, packet_buffer, &packet_size,
				    header->icookie, header->rcookie,
				    0, VERIFICATION_FAILURE);
	     send_packet();
	     return 0;
	}

	bcopy(header->SPI, st->uSPI, SPI_SIZE);
	st->ulifetime = (header->lifetime[0] << 16) + 
	     (header->lifetime[1] << 8) + header->lifetime[2];

	st->lifetime = st->exchange_lifetime + time(NULL) + random() % 20;
	st->retries = 0;
	st->phase = SPI_UPDATE;

	schedule_remove(TIMEOUT, st->icookie);

	/* We don't need the packet buffer anylonger */
	if (st->packet != NULL) {
	     free(st->packet);
	     st->packet = NULL;
	     st->packetlen = 0;
	}
		  
	/* At this point we do not need the exchange values any longer */
	free(st->texchange); st->texchange = NULL;
	free(st->exchangevalue); st->exchangevalue = NULL;

	if (st->oSPI[0] || st->oSPI[1] || st->oSPI[2] || st->oSPI[3]) {
	     /* Insert Owner SPI */
	     if ((spi = spi_new(st->address, st->oSPI)) == NULL) {
		  log_error(0, "spi_new() in handle_identity_response()");
		  return -1;
	     }
	     if ((spi->local_address = strdup(local_address)) == NULL) {
		  log_error(1, "strdup() in handle_identity_response()");
		  return -1;
	     }
	     bcopy(st->icookie, spi->icookie, COOKIE_SIZE);
	     spi->flags |= SPI_OWNER;
	     spi->attribsize = st->oSPIattribsize;
	     spi->attributes = calloc(spi->attribsize, sizeof(u_int8_t));
	     if (spi->attributes == NULL) {
		  log_error(0, "calloc() in handle_identity_response()");
		  spi_value_reset(spi);
		  return -1;
	     }
	     bcopy(st->oSPIattrib, spi->attributes, spi->attribsize);
	     spi->lifetime = time(NULL) + st->olifetime;

	     /* Cludge for getting the right verification field */
	     state_save_verification(st, st->oSPIidentver, st->oSPIidentversize);
	     /* Make session keys for Owner */
	     make_session_keys(st, spi);

	     spi_insert(spi);
#ifdef IPSEC
	     kernel_insert_spi(st, spi);
#endif
	     schedule_insert(UPDATE, st->olifetime/2, spi->SPI, SPI_SIZE);
	}
	if (st->uSPI[0] || st->uSPI[1] || st->uSPI[2] || st->uSPI[3]) {
	     /* Insert User SPI */
	     if ((spi = spi_new(st->address, st->uSPI)) == NULL) {
		  log_error(0, "spi_new() in handle_identity_response()");
		  return -1;
	     }
	     if ((spi->local_address = strdup(local_address)) == NULL) {
		  log_error(1, "strdup() in handle_identity_response()");
		  return -1;
	     }
	     spi->flags |= st->flags & IPSEC_NOTIFY ? SPI_NOTIFY : 0;
	     bcopy(st->icookie, spi->icookie, COOKIE_SIZE);
	     spi->attribsize = st->uSPIattribsize;
	     spi->attributes = calloc(spi->attribsize, sizeof(u_int8_t));
	     if (spi->attributes == NULL) {
		  log_error(1, "calloc() in handle_identity_response()");
		  spi_value_reset(spi);
		  return -1;
	     }
	     bcopy(st->uSPIattrib, spi->attributes, spi->attribsize);
	     spi->lifetime = time(NULL) + st->ulifetime;

	     /* Cludge for getting the right verification field */
	     state_save_verification(st, st->uSPIidentver, st->uSPIidentversize);
	     /* Session keys for User */
	     make_session_keys(st, spi);

	     spi_set_tunnel(st, spi);

	     spi_insert(spi);
#ifdef IPSEC
	     kernel_insert_spi(st, spi);
#endif
	}
	return 0;
}