path: root/sbin/isakmpd/ike_auth.c

/*	$OpenBSD: ike_auth.c,v 1.78 2003/06/10 16:41:29 deraadt Exp $	*/
/*	$EOM: ike_auth.c,v 1.59 2000/11/21 00:21:31 angelos Exp $	*/

/*
 * Copyright (c) 1998, 1999, 2000, 2001 Niklas Hallqvist.  All rights reserved.
 * Copyright (c) 1999 Niels Provos.  All rights reserved.
 * Copyright (c) 1999 Angelos D. Keromytis.  All rights reserved.
 * Copyright (c) 2000, 2001, 2003 Håkan Olsson.  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.
 *
 * 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.
 */

/*
 * This code was written under funding by Ericsson Radio Systems.
 */

#include <sys/types.h>
#include <sys/stat.h>
#include <unistd.h>
#include <fcntl.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdlib.h>
#include <string.h>
#include <regex.h>
#if defined (USE_KEYNOTE)
#include <keynote.h>
#endif
#include <policy.h>

#include "sysdep.h"

#include "cert.h"
#include "conf.h"
#include "constants.h"
#if defined (USE_DNSSEC)
#include "dnssec.h"
#endif
#include "exchange.h"
#include "gmp_util.h"
#include "hash.h"
#include "ike_auth.h"
#include "ipsec.h"
#include "ipsec_doi.h"
#include "libcrypto.h"
#include "log.h"
#include "message.h"
#include "monitor.h"
#include "prf.h"
#include "transport.h"
#include "util.h"
#include "key.h"
#if defined (USE_X509)
#include "x509.h"
#endif

#ifdef notyet
static u_int8_t *enc_gen_skeyid (struct exchange *, size_t *);
#endif
static u_int8_t *pre_shared_gen_skeyid (struct exchange *, size_t *);

static int pre_shared_decode_hash (struct message *);
static int pre_shared_encode_hash (struct message *);

#if defined (USE_X509) || defined (USE_KEYNOTE)
static u_int8_t *sig_gen_skeyid (struct exchange *, size_t *);
static int rsa_sig_decode_hash (struct message *);
static int rsa_sig_encode_hash (struct message *);
#endif

#if defined (USE_RAWKEY)
static int get_raw_key_from_file (int, u_int8_t *, size_t, RSA **);
#endif

static int ike_auth_hash (struct exchange *, u_int8_t *);

static struct ike_auth ike_auth[] = {
  {
    IKE_AUTH_PRE_SHARED, pre_shared_gen_skeyid, pre_shared_decode_hash,
    pre_shared_encode_hash
  },
#ifdef notdef
  {
    IKE_AUTH_DSS, sig_gen_skeyid, pre_shared_decode_hash,
    pre_shared_encode_hash
  },
#endif
#if defined (USE_X509) || defined (USE_KEYNOTE)
  {
    IKE_AUTH_RSA_SIG, sig_gen_skeyid, rsa_sig_decode_hash,
    rsa_sig_encode_hash
  },
#endif
#ifdef notdef
  {
    IKE_AUTH_RSA_ENC, enc_gen_skeyid, pre_shared_decode_hash,
    pre_shared_encode_hash
  },
  {
    IKE_AUTH_RSA_ENC_REV, enc_gen_skeyid, pre_shared_decode_hash,
    pre_shared_encode_hash
  },
#endif
};

struct ike_auth *
ike_auth_get (u_int16_t id)
{
  int i;

  for (i = 0; i < sizeof ike_auth / sizeof ike_auth[0]; i++)
    if (id == ike_auth[i].id)
      return &ike_auth[i];
  return 0;
}

/*
 * Find and decode the configured key (pre-shared or public) for the
 * peer denoted by ID.  Stash the len in KEYLEN.
 */
static void *
ike_auth_get_key (int type, char *id, char *local_id, size_t *keylen)
{
  char *key, *buf;
#if defined (USE_X509) || defined (USE_KEYNOTE)
  char *keyfile;
#if defined (USE_X509)
  BIO *keyh;
  RSA *rsakey;
  size_t fsize;
#endif
#endif

  switch (type)
    {
    case IKE_AUTH_PRE_SHARED:
      /* Get the pre-shared key for our peer.  */
      key = conf_get_str (id, "Authentication");
      if (!key && local_id)
	key = conf_get_str (local_id, "Authentication");

      if (!key)
        {
	  log_print ("ike_auth_get_key: "
		     "no key found for peer \"%s\" or local ID \"%s\"",
		     id, local_id);
	  return 0;
	}

      /* If the key starts with 0x it is in hex format.  */
      if (strncasecmp (key, "0x", 2) == 0)
	{
	  *keylen = (strlen (key) - 1) / 2;
	  buf = malloc (*keylen);
	  if (!buf)
	    {
	      log_print ("ike_auth_get_key: malloc (%lu) failed",
		(unsigned long)*keylen);
	      return 0;
	    }
	  if (hex2raw (key + 2, (unsigned char *)buf, *keylen))
	    {
	      free (buf);
	      log_print ("ike_auth_get_key: invalid hex key %s", key);
	      return 0;
	    }
	  key = buf;
	}
      else
	*keylen = strlen (key);
      break;

    case IKE_AUTH_RSA_SIG:
#if defined (USE_X509) || defined (USE_KEYNOTE)
#if defined (USE_KEYNOTE)
      if (local_id &&
	  (keyfile = conf_get_str ("KeyNote", "Credential-directory")) != 0)
        {
	  struct stat sb;
	  struct keynote_deckey dc;
	  char *privkeyfile, *buf2;
	  int fd, pkflen;
	  size_t size;

	  pkflen = strlen (keyfile) + strlen (local_id) +
	    sizeof PRIVATE_KEY_FILE + sizeof "//" - 1;
	  privkeyfile = calloc (pkflen, sizeof (char));
	  if (!privkeyfile)
	    {
	      log_print ("ike_auth_get_key: failed to allocate %d bytes",
			 pkflen);
	      return 0;
	    }

	  snprintf (privkeyfile, pkflen, "%s/%s/%s", keyfile, local_id,
		   PRIVATE_KEY_FILE);
	  keyfile = privkeyfile;

	  if (stat (keyfile, &sb) < 0)
	    {
	      free (keyfile);
	      goto ignorekeynote;
	    }
	  size = (size_t)sb.st_size;

	  fd = open (keyfile, O_RDONLY, 0);
	  if (fd < 0)
	    {
	      log_print ("ike_auth_get_key: failed opening \"%s\"", keyfile);
	      free (keyfile);
	      return 0;
	    }

	  buf = calloc (size + 1, sizeof (char));
	  if (!buf)
	    {
	      log_print ("ike_auth_get_key: failed allocating %lu bytes",
			 (unsigned long)size + 1);
	      free (keyfile);
	      return 0;
	    }

	  if (read (fd, buf, size) != size)
	    {
	      free (buf);
	      log_print ("ike_auth_get_key: "
			 "failed reading %lu bytes from \"%s\"",
			(unsigned long)size, keyfile);
	      free (keyfile);
	      return 0;
	    }

	  close (fd);

	  /* Parse private key string */
	  buf2 = kn_get_string (buf);
	  free (buf);

	  if (kn_decode_key (&dc, buf2, KEYNOTE_PRIVATE_KEY) == -1)
	    {
	      free (buf2);
	      log_print ("ike_auth_get_key: failed decoding key in \"%s\"",
			 keyfile);
	      free (keyfile);
	      return 0;
	    }

	  free (buf2);

	  if (dc.dec_algorithm != KEYNOTE_ALGORITHM_RSA)
	    {
	      log_print ("ike_auth_get_key: wrong algorithm type %d in \"%s\"",
			 dc.dec_algorithm, keyfile);
	      free (keyfile);
	      kn_free_key (&dc);
	      return 0;
	    }

	  free (keyfile);
	  return dc.dec_key;
	}

    ignorekeynote:
#endif /* USE_KEYNOTE */
#ifdef USE_X509
      /* Otherwise, try X.509 */
      keyfile = conf_get_str ("X509-certificates", "Private-key");

      if (check_file_secrecy (keyfile, &fsize))
	return 0;

      keyh = BIO_new (BIO_s_file ());
      if (keyh == NULL)
	{
	  log_print ("ike_auth_get_key: "
		     "BIO_new (BIO_s_file ()) failed");
	  return 0;
	}
      if (BIO_read_filename (keyh, keyfile) == -1)
	{
	  log_print ("ike_auth_get_key: "
		     "BIO_read_filename (keyh, \"%s\") failed",
		     keyfile);
	  BIO_free (keyh);
	  return 0;
	}

#if SSLEAY_VERSION_NUMBER >= 0x00904100L
      rsakey = PEM_read_bio_RSAPrivateKey (keyh, NULL, NULL, NULL);
#else
      rsakey = PEM_read_bio_RSAPrivateKey (keyh, NULL, NULL);
#endif
      BIO_free (keyh);
      if (!rsakey)
	{
	  log_print ("ike_auth_get_key: PEM_read_bio_RSAPrivateKey failed");
	  return 0;
	}

      return rsakey;
#endif /* USE_X509 */
#endif /* USE_X509 || USE_KEYNOTE */

    default:
      log_print ("ike_auth_get_key: unknown key type %d", type);
      return 0;
    }

  return key;
}

static u_int8_t *
pre_shared_gen_skeyid (struct exchange *exchange, size_t *sz)
{
  struct prf *prf;
  struct ipsec_exch *ie = exchange->data;
  u_int8_t *skeyid;
  u_int8_t *buf = 0;
  unsigned char *key;
  size_t keylen;

  /*
   * If we're the responder and have the initiator's ID (which is the
   * case in Aggressive mode), try to find the preshared key in the
   * section of the initiator's Phase 1 ID.  This allows us to do
   * mobile user support with preshared keys.
   */
  if (!exchange->initiator && exchange->id_i)
    {
      switch (exchange->id_i[0])
        {
	case IPSEC_ID_IPV4_ADDR:
	case IPSEC_ID_IPV6_ADDR:
	  util_ntoa ((char **)&buf,
		     exchange->id_i[0] == IPSEC_ID_IPV4_ADDR
		     ? AF_INET : AF_INET6,
		     exchange->id_i + ISAKMP_ID_DATA_OFF - ISAKMP_GEN_SZ);
	  if (!buf)
	    return 0;
	  break;

	case IPSEC_ID_FQDN:
	case IPSEC_ID_USER_FQDN:
	  buf = calloc (exchange->id_i_len - ISAKMP_ID_DATA_OFF
			+ ISAKMP_GEN_SZ + 1, sizeof (char));
	  if (!buf)
	    {
              log_print ("pre_shared_gen_skeyid: malloc (%lu) failed",
			 (unsigned long)exchange->id_i_len - ISAKMP_ID_DATA_OFF
			 + ISAKMP_GEN_SZ + 1);
	      return 0;
	    }
	  memcpy (buf, exchange->id_i + ISAKMP_ID_DATA_OFF - ISAKMP_GEN_SZ,
		  exchange->id_i_len - ISAKMP_ID_DATA_OFF + ISAKMP_GEN_SZ);
	  break;

	  /* XXX Support more ID types ? */
	default:
	  break;
	}
    }

  /*
   * Get the pre-shared key for our peer. This will work even if the key
   * has been passed to us through a mechanism like PFKEYv2.
   */
  key = ike_auth_get_key (IKE_AUTH_PRE_SHARED, exchange->name, (char *)buf,
			  &keylen);
  if (buf)
    free (buf);

  /* Fail if no key could be found.  */
  if (!key)
    return 0;

  /* Store the secret key for later policy processing.  */
  exchange->recv_key = calloc (keylen + 1, sizeof (char));
  exchange->recv_keytype = ISAKMP_KEY_PASSPHRASE;
  if (!exchange->recv_key)
    {
      log_error ("pre_shared_gen_skeyid: malloc (%lu) failed",
	(unsigned long)keylen);
      return 0;
    }
  memcpy (exchange->recv_key, key, keylen);
  exchange->recv_certtype = ISAKMP_CERTENC_NONE;

  prf = prf_alloc (ie->prf_type, ie->hash->type, key, keylen);
  if (!prf)
    return 0;

  *sz = prf->blocksize;
  skeyid = malloc (*sz);
  if (!skeyid)
    {
      log_error ("pre_shared_gen_skeyid: malloc (%lu) failed",
	(unsigned long)*sz);
      prf_free (prf);
      return 0;
    }

  prf->Init (prf->prfctx);
  prf->Update (prf->prfctx, exchange->nonce_i, exchange->nonce_i_len);
  prf->Update (prf->prfctx, exchange->nonce_r, exchange->nonce_r_len);
  prf->Final (skeyid, prf->prfctx);
  prf_free (prf);

  return skeyid;
}

#if defined (USE_X509) || defined (USE_KEYNOTE)
/* Both DSS & RSA signature authentication use this algorithm.  */
static u_int8_t *
sig_gen_skeyid (struct exchange *exchange, size_t *sz)
{
  struct prf *prf;
  struct ipsec_exch *ie = exchange->data;
  u_int8_t *skeyid;
  unsigned char *key;

  key = malloc (exchange->nonce_i_len + exchange->nonce_r_len);
  if (!key)
    return 0;
  memcpy (key, exchange->nonce_i, exchange->nonce_i_len);
  memcpy (key + exchange->nonce_i_len, exchange->nonce_r,
	  exchange->nonce_r_len);

  LOG_DBG((LOG_NEGOTIATION, 80, "sig_gen_skeyid: PRF type %d, hash %d",
      ie->prf_type, ie->hash->type));
  LOG_DBG_BUF((LOG_NEGOTIATION, 80, "sig_gen_skeyid: SKEYID initialized with",
      (u_int8_t *)key, exchange->nonce_i_len + exchange->nonce_r_len));

  prf = prf_alloc (ie->prf_type, ie->hash->type, key,
		   exchange->nonce_i_len + exchange->nonce_r_len);
  free (key);
  if (!prf)
    return 0;

  *sz = prf->blocksize;
  skeyid = malloc (*sz);
  if (!skeyid)
    {
      log_error ("sig_gen_skeyid: malloc (%lu) failed",
	(unsigned long)*sz);
      prf_free (prf);
      return 0;
    }

  LOG_DBG((LOG_NEGOTIATION, 80, "sig_gen_skeyid: g^xy length %lu",
      (unsigned long)ie->g_x_len));
  LOG_DBG_BUF((LOG_NEGOTIATION, 80,
      "sig_gen_skeyid: SKEYID fed with g^xy", ie->g_xy, ie->g_x_len));

  prf->Init (prf->prfctx);
  prf->Update (prf->prfctx, ie->g_xy, ie->g_x_len);
  prf->Final (skeyid, prf->prfctx);
  prf_free (prf);

  return skeyid;
}
#endif /* USE_X509 || USE_KEYNOTE */

#ifdef notdef
/*
 * Both standard and revised RSA encryption authentication use this SKEYID
 * computation.
 */
static u_int8_t *
enc_gen_skeyid (struct exchange *exchange, size_t *sz)
{
  struct prf *prf;
  struct ipsec_exch *ie = exchange->data;
  struct hash *hash = ie->hash;
  u_int8_t *skeyid;

  hash->Init (hash->ctx);
  hash->Update (hash->ctx, exchange->nonce_i, exchange->nonce_i_len);
  hash->Update (hash->ctx, exchange->nonce_r, exchange->nonce_r_len);
  hash->Final (hash->digest, hash->ctx);
  prf = prf_alloc (ie->prf_type, hash->type, hash->digest, *sz);
  if (!prf)
    return 0;

  *sz = prf->blocksize;
  skeyid = malloc (*sz);
  if (!skeyid)
    {
      log_error ("enc_gen_skeyid: malloc (%d) failed", *sz);
      prf_free (prf);
      return 0;
    }

  prf->Init (prf->prfctx);
  prf->Update (prf->prfctx, exchange->cookies, ISAKMP_HDR_COOKIES_LEN);
  prf->Final (skeyid, prf->prfctx);
  prf_free (prf);

  return skeyid;
}
#endif /* notdef */

static int
pre_shared_decode_hash (struct message *msg)
{
  struct exchange *exchange = msg->exchange;
  struct ipsec_exch *ie = exchange->data;
  struct payload *payload;
  size_t hashsize = ie->hash->hashsize;
  char header[80];
  int initiator = exchange->initiator;
  u_int8_t **hash_p;

  /* Choose the right fields to fill-in.  */
  hash_p = initiator ? &ie->hash_r : &ie->hash_i;

  payload = TAILQ_FIRST (&msg->payload[ISAKMP_PAYLOAD_HASH]);
  if (!payload)
    {
      log_print ("pre_shared_decode_hash: no HASH payload found");
      return -1;
    }

  /* Check that the hash is of the correct size.  */
  if (GET_ISAKMP_GEN_LENGTH (payload->p) - ISAKMP_GEN_SZ != hashsize)
    return -1;

  /* XXX Need this hash be in the SA?  */
  *hash_p = malloc (hashsize);
  if (!*hash_p)
    {
      log_error ("pre_shared_decode_hash: malloc (%lu) failed",
	(unsigned long)hashsize);
      return -1;
    }

  memcpy (*hash_p, payload->p + ISAKMP_HASH_DATA_OFF, hashsize);
  snprintf (header, sizeof header, "pre_shared_decode_hash: HASH_%c",
	    initiator ? 'R' : 'I');
  LOG_DBG_BUF ((LOG_MISC, 80, header, *hash_p, hashsize));

  payload->flags |= PL_MARK;

  return 0;
}

#if defined (USE_X509) || defined (USE_KEYNOTE)
/* Decrypt the HASH in SIG, we already need a parsed ID payload.  */
static int
rsa_sig_decode_hash (struct message *msg)
{
  struct cert_handler *handler;
  struct exchange *exchange = msg->exchange;
  struct ipsec_exch *ie = exchange->data;
  struct payload *p;
  void *cert = 0;
  u_int8_t *rawcert = 0;
  u_int32_t rawcertlen;
  RSA *key = 0;
  size_t hashsize = ie->hash->hashsize;
  char header[80];
  int len;
  int initiator = exchange->initiator;
  u_int8_t **hash_p, **id_cert, *id;
  u_int32_t *id_cert_len;
  size_t id_len;
  int found = 0, n, i, id_found;
#if defined (USE_DNSSEC)
  u_int8_t *rawkey = 0;
  u_int32_t rawkeylen;
#endif

  /* Choose the right fields to fill-in.  */
  hash_p = initiator ? &ie->hash_r : &ie->hash_i;
  id = initiator ? exchange->id_r : exchange->id_i;
  id_len = initiator ? exchange->id_r_len : exchange->id_i_len;

  if (!id || id_len == 0)
    {
      log_print ("rsa_sig_decode_hash: ID is missing");
      return -1;
    }

  /*
   * XXX Assume we should use the same kind of certification as the remote...
   * moreover, just use the first CERT payload to decide what to use.
   */
  p = TAILQ_FIRST (&msg->payload[ISAKMP_PAYLOAD_CERT]);
  if (!p)
    handler = cert_get (ISAKMP_CERTENC_KEYNOTE);
  else
    handler = cert_get (GET_ISAKMP_CERT_ENCODING (p->p));
  if (!handler)
    {
      log_print ("rsa_sig_decode_hash: cert_get (%d) failed",
		 p ? GET_ISAKMP_CERT_ENCODING (p->p) : -1);
      return -1;
    }

#if defined (USE_POLICY) || defined (USE_KEYNOTE)
  /*
   * We need the policy session initialized now, so we can add
   * credentials etc.
   */
  exchange->policy_id = kn_init ();
  if (exchange->policy_id == -1)
    {
      log_print ("rsa_sig_decode_hash: failed to initialize policy session");
      return -1;
    }
#endif /* USE_POLICY || USE_KEYNOTE */

  /* Obtain a certificate from our certificate storage.  */
  if (handler->cert_obtain (id, id_len, 0, &rawcert, &rawcertlen))
    {
      if (handler->id == ISAKMP_CERTENC_X509_SIG)
        {
	  cert = handler->cert_get (rawcert, rawcertlen);
	  if (!cert)
	    LOG_DBG ((LOG_CRYPTO, 50,
		      "rsa_sig_decode_hash: certificate malformed"));
	  else
	    {
	      if (!handler->cert_get_key (cert, &key))
	        {
		  log_print ("rsa_sig_decode_hash: "
			     "decoding certificate failed");
		  handler->cert_free (cert);
		}
	      else
	        {
		  found++;
		  LOG_DBG ((LOG_CRYPTO, 40,
			    "rsa_sig_decode_hash: using cert of type %d",
			    handler->id));
		  exchange->recv_cert = cert;
		  exchange->recv_certtype = handler->id;
#if defined (USE_POLICY)
		  x509_generate_kn (exchange->policy_id, cert);
#endif /* USE_POLICY */
		}
	    }
	}
      else if (handler->id == ISAKMP_CERTENC_KEYNOTE)
	handler->cert_insert (exchange->policy_id, rawcert);
      free (rawcert);
    }

  /*
   * Walk over potential CERT payloads in this message.
   * XXX I believe this is the wrong spot for this.  CERTs can appear
   * anytime.
   */
  for (p = TAILQ_FIRST (&msg->payload[ISAKMP_PAYLOAD_CERT]); p;
       p = TAILQ_NEXT (p, link))
    {
      p->flags |= PL_MARK;

      /* When we have found a key, just walk over the rest, marking them.  */
      if (found)
	continue;

      handler = cert_get (GET_ISAKMP_CERT_ENCODING (p->p));
      if (!handler)
	{
	  LOG_DBG ((LOG_MISC, 30,
		    "rsa_sig_decode_hash: no handler for %s CERT encoding",
		    constant_lookup (isakmp_certenc_cst,
				     GET_ISAKMP_CERT_ENCODING (p->p))));
	  continue;
	}

      cert = handler->cert_get (p->p + ISAKMP_CERT_DATA_OFF,
				GET_ISAKMP_GEN_LENGTH (p->p)
				- ISAKMP_CERT_DATA_OFF);
      if (!cert)
	{
	  log_print ("rsa_sig_decode_hash: can not get data from CERT");
	  continue;
	}

      if (!handler->cert_validate (cert))
	{
	  handler->cert_free (cert);
	  log_print ("rsa_sig_decode_hash: received CERT can't be validated");
	  continue;
	}

      if (GET_ISAKMP_CERT_ENCODING (p->p) == ISAKMP_CERTENC_X509_SIG)
        {
	  if (!handler->cert_get_subjects (cert, &n, &id_cert, &id_cert_len))
	    {
	      handler->cert_free (cert);
	      log_print ("rsa_sig_decode_hash: can not get subject from CERT");
	      continue;
	    }

	  id_found = 0;
	  for (i = 0; i < n; i++)
	    if (id_cert_len[i] == id_len
		&& id[0] == id_cert[i][0]
		&& memcmp (id + 4, id_cert[i] + 4, id_len - 4) == 0)
	      {
		id_found++;
		break;
	      }
	  if (!id_found)
	    {
	      handler->cert_free (cert);
	      log_print ("rsa_sig_decode_hash: no CERT subject match the ID");
	      free (id_cert);
	      continue;
	    }

	  cert_free_subjects (n, id_cert, id_cert_len);
	}

      if (!handler->cert_get_key (cert, &key))
	{
	  handler->cert_free (cert);
	  log_print ("rsa_sig_decode_hash: decoding payload CERT failed");
	  continue;
	}

      /* We validated the cert, cache it for later use.  */
      handler->cert_insert (exchange->policy_id, cert);

      exchange->recv_cert = cert;
      exchange->recv_certtype = GET_ISAKMP_CERT_ENCODING (p->p);

#if defined (USE_POLICY) || defined (USE_KEYNOTE)
      if (exchange->recv_certtype == ISAKMP_CERTENC_KEYNOTE)
        {
	  struct keynote_deckey dc;
	  char *pp;
	  int dclen;

	  dc.dec_algorithm = KEYNOTE_ALGORITHM_RSA;
	  dc.dec_key = key;

	  pp = kn_encode_key (&dc, INTERNAL_ENC_PKCS1, ENCODING_HEX,
			      KEYNOTE_PUBLIC_KEY);
	  if (pp == NULL)
	    {
	      kn_free_key (&dc);
	      log_print ("rsa_sig_decode_hash: failed to ASCII-encode key");
	      return -1;
	    }

	  dclen = strlen (pp) + sizeof "rsa-hex:";
	  exchange->keynote_key = calloc (dclen, sizeof (char));
	  if (!exchange->keynote_key)
	    {
	      free (pp);
	      kn_free_key (&dc);
	      log_print ("rsa_sig_decode_hash: failed to allocate %d bytes",
			 dclen);
	      return -1;
	    }

	  snprintf (exchange->keynote_key, dclen, "rsa-hex:%s", pp);
	  free (pp);
	}
#endif

      found++;
    }

#if defined (USE_DNSSEC)
  /* If no certificate provided a key, try to find a validated DNSSEC KEY.  */
  if (!found)
    {
      rawkey = dns_get_key (IKE_AUTH_RSA_SIG, msg, &rawkeylen);

      /* We need to convert 'void *rawkey' into 'RSA *key'.  */
      if (dns_RSA_dns_to_x509 (rawkey, rawkeylen, &key) == 0)
	found++;
      else
	log_print ("rsa_sig_decode_hash: KEY to RSA key conversion failed");

      if (rawkey)
	free (rawkey);
    }
#endif /* USE_DNSSEC */

#if defined (USE_RAWKEY)
  /* If we still have not found a key, try to read it from a file. */
  if (!found)
    if (get_raw_key_from_file (IKE_AUTH_RSA_SIG, id, id_len, &key) != -1)
      found++;
#endif

  if (!found)
    {
      log_print ("rsa_sig_decode_hash: no public key found");
      return -1;
    }

  p = TAILQ_FIRST (&msg->payload[ISAKMP_PAYLOAD_SIG]);
  if (!p)
    {
      log_print ("rsa_sig_decode_hash: missing signature payload");
      RSA_free (key);
      return -1;
    }

  /* Check that the sig is of the correct size.  */
  len = GET_ISAKMP_GEN_LENGTH (p->p) - ISAKMP_SIG_SZ;
  if (len != RSA_size (key))
    {
      RSA_free (key);
      log_print ("rsa_sig_decode_hash: "
		 "SIG payload length does not match public key");
      return -1;
    }

  *hash_p = malloc (len);
  if (!*hash_p)
    {
      RSA_free (key);
      log_error ("rsa_sig_decode_hash: malloc (%d) failed", len);
      return -1;
    }

  len = RSA_public_decrypt (len, p->p + ISAKMP_SIG_DATA_OFF, *hash_p, key,
			    RSA_PKCS1_PADDING);
  if (len == -1)
    {
      RSA_free (key);
      log_print ("rsa_sig_decode_hash: RSA_public_decrypt () failed");
      return -1;
    }

  /* Store key for later use */
  exchange->recv_key = key;
  exchange->recv_keytype = ISAKMP_KEY_RSA;

  if (len != hashsize)
    {
      free (*hash_p);
      *hash_p = 0;
      log_print ("rsa_sig_decode_hash: len %lu != hashsize %lu",
	(unsigned long)len, (unsigned long)hashsize);
      return -1;
    }

  snprintf (header, sizeof header, "rsa_sig_decode_hash: HASH_%c",
	    initiator ? 'R' : 'I');
  LOG_DBG_BUF ((LOG_MISC, 80, header, *hash_p, hashsize));

  p->flags |= PL_MARK;

  return 0;
}
#endif /* USE_X509 || USE_KEYNOTE */

static int
pre_shared_encode_hash (struct message *msg)
{
  struct exchange *exchange = msg->exchange;
  struct ipsec_exch *ie = exchange->data;
  size_t hashsize = ie->hash->hashsize;
  char header[80];
  int initiator = exchange->initiator;
  u_int8_t *buf;

  buf = ipsec_add_hash_payload (msg, hashsize);
  if (!buf)
    return -1;

  if (ike_auth_hash (exchange, buf + ISAKMP_HASH_DATA_OFF) == -1)
    return -1;

  snprintf (header, sizeof header, "pre_shared_encode_hash: HASH_%c",
	    initiator ? 'I' : 'R');
  LOG_DBG_BUF ((LOG_MISC, 80, header, buf + ISAKMP_HASH_DATA_OFF, hashsize));
  return 0;
}

#if defined (USE_X509) || defined (USE_KEYNOTE)
/* Encrypt the HASH into a SIG type.  */
static int
rsa_sig_encode_hash (struct message *msg)
{
  struct exchange *exchange = msg->exchange;
  struct ipsec_exch *ie = exchange->data;
  size_t hashsize = ie->hash->hashsize;
  struct cert_handler *handler;
  char header[80];
  int initiator = exchange->initiator;
  u_int8_t *buf, *data, *buf2;
  u_int32_t datalen;
  u_int8_t *id;
  size_t id_len;
  int idtype;
  void *sent_key;

  id = initiator ? exchange->id_i : exchange->id_r;
  id_len = initiator ? exchange->id_i_len : exchange->id_r_len;

  /* We may have been provided these by the kernel */
  buf = (u_int8_t *)conf_get_str (exchange->name, "Credentials");
  if (buf
      && (idtype = conf_get_num (exchange->name, "Credential_Type", -1) != -1))
    {
      exchange->sent_certtype = idtype;
      handler = cert_get (idtype);
      if (!handler)
	{
	  log_print ("rsa_sig_encode_hash: cert_get (%d) failed", idtype);
	  return -1;
	}

      exchange->sent_cert = handler->cert_from_printable ((char *)buf);
      if (!exchange->sent_cert)
	{
	  log_print ("rsa_sig_encode_hash: failed to retrieve certificate");
	  return -1;
	}

      handler->cert_serialize (exchange->sent_cert, &data, &datalen);
      if (!data)
	{
	  log_print ("rsa_sig_encode_hash: cert serialization failed");
	  return -1;
	}

      goto aftercert; /* Skip all the certificate discovery */
    }

  /* XXX This needs to be configurable.  */
  idtype = ISAKMP_CERTENC_KEYNOTE;

  /* Find a certificate with subjectAltName = id.  */
  handler = cert_get (idtype);
  if (!handler)
    {
      idtype = ISAKMP_CERTENC_X509_SIG;
      handler = cert_get (idtype);
      if (!handler)
	{
	  log_print ("rsa_sig_encode_hash: cert_get(%d) failed", idtype);
	  return -1;
	}
    }

  if (handler->cert_obtain (id, id_len, 0, &data, &datalen) == 0)
    {
      if (idtype == ISAKMP_CERTENC_KEYNOTE)
	{
	  idtype = ISAKMP_CERTENC_X509_SIG;
	  handler = cert_get (idtype);
	  if (!handler)
	    {
	      log_print ("rsa_sig_encode_hash: cert_get(%d) failed", idtype);
	      return -1;
	    }

	  if (handler->cert_obtain (id, id_len, 0, &data, &datalen) == 0)
	    {
	      LOG_DBG ((LOG_MISC, 10,
			"rsa_sig_encode_hash: no certificate to send"));
	      goto skipcert;
	    }
	}
      else
	{
	  LOG_DBG ((LOG_MISC, 10,
		    "rsa_sig_encode_hash: no certificate to send"));
	  goto skipcert;
	}
    }

  /* Let's store the certificate we are going to use */
  exchange->sent_certtype = idtype;
  exchange->sent_cert = handler->cert_get (data, datalen);
  if (!exchange->sent_cert)
    {
      free (data);
      log_print ("rsa_sig_encode_hash: failed to get certificate from wire "
		 "encoding");
      return -1;
    }

 aftercert:

  buf = realloc (data, ISAKMP_CERT_SZ + datalen);
  if (!buf)
    {
      log_error ("rsa_sig_encode_hash: realloc (%p, %d) failed", data,
		 ISAKMP_CERT_SZ + datalen);
      free (data);
      return -1;
    }
  memmove (buf + ISAKMP_CERT_SZ, buf, datalen);
  SET_ISAKMP_CERT_ENCODING (buf, idtype);
  if (message_add_payload (msg, ISAKMP_PAYLOAD_CERT, buf,
			   ISAKMP_CERT_SZ + datalen, 1))
    {
      free (buf);
      return -1;
    }

 skipcert:

  /* Again, we may have these from the kernel */
  buf = (u_int8_t *)conf_get_str (exchange->name, "PKAuthentication");
  if (buf)
    {
      key_from_printable (ISAKMP_KEY_RSA, ISAKMP_KEYTYPE_PRIVATE, (char *)buf,
			  &data, &datalen);
      if (!data || datalen == -1)
	{
	  log_print ("rsa_sig_encode_hash: badly formatted RSA private key");
	  return 0;
	}

      sent_key = key_internalize (ISAKMP_KEY_RSA, ISAKMP_KEYTYPE_PRIVATE, data,
				  datalen);
      if (!sent_key)
	{
	  log_print ("rsa_sig_encode_hash: bad RSA private key from dynamic "
		     "SA acquisition subsystem");
	  return 0;
	}
#if defined (USE_PRIVSEP)
      {
	/* With USE_PRIVSEP, the sent_key should be a key number. */
	void *key = sent_key;
	sent_key = monitor_RSA_upload_key (key);
      }
#endif
    }
  else /* Try through the regular means.  */
    {
      switch (id[ISAKMP_ID_TYPE_OFF - ISAKMP_GEN_SZ])
	{
	case IPSEC_ID_IPV4_ADDR:
	case IPSEC_ID_IPV6_ADDR:
	  util_ntoa ((char **)&buf2,
		     id[ISAKMP_ID_TYPE_OFF - ISAKMP_GEN_SZ] == IPSEC_ID_IPV4_ADDR
		     ? AF_INET : AF_INET6,
		     id + ISAKMP_ID_DATA_OFF - ISAKMP_GEN_SZ);
	  if (!buf2)
	    return 0;
	  break;

	case IPSEC_ID_FQDN:
	case IPSEC_ID_USER_FQDN:
	  buf2 = calloc (id_len - ISAKMP_ID_DATA_OFF + ISAKMP_GEN_SZ + 1,
			 sizeof (char));
	  if (!buf2)
	    {
	      log_print ("rsa_sig_encode_hash: malloc (%lu) failed",
			 (unsigned long)id_len - ISAKMP_ID_DATA_OFF + ISAKMP_GEN_SZ + 1);
	      return 0;
	    }
	  memcpy (buf2, id + ISAKMP_ID_DATA_OFF - ISAKMP_GEN_SZ,
		  id_len - ISAKMP_ID_DATA_OFF + ISAKMP_GEN_SZ);
	  break;

	  /* XXX Support more ID types?  */
	default:
	  buf2 = 0;
	  return 0;
	}

#if defined (USE_PRIVSEP)
      sent_key = monitor_RSA_get_private_key (exchange->name, (char *)buf2);
#else
      sent_key = ike_auth_get_key (IKE_AUTH_RSA_SIG, exchange->name,
				   (char *)buf2, 0);
#endif
      free (buf2);

      /* Did we find a key?  */
      if (!sent_key)
	{
	  log_print ("rsa_sig_encode_hash: could not get private key");
	  return -1;
	}
    }

#if !defined (USE_PRIVSEP)
  /* Enable RSA blinding.  */
  if (RSA_blinding_on (sent_key, NULL) != 1)
    {
      log_error ("rsa_sig_encode_hash: RSA_blinding_on () failed.");
      return -1;
    }
#endif

  /* XXX hashsize is not necessarily prf->blocksize.  */
  buf = malloc (hashsize);
  if (!buf)
    {
      log_error ("rsa_sig_encode_hash: malloc (%lu) failed",
	(unsigned long)hashsize);
      return -1;
    }

  if (ike_auth_hash (exchange, buf) == -1)
    {
      free (buf);
      return -1;
    }

  snprintf (header, sizeof header, "rsa_sig_encode_hash: HASH_%c",
	    initiator ? 'I' : 'R');
  LOG_DBG_BUF ((LOG_MISC, 80, header, buf, hashsize));

#if !defined (USE_PRIVSEP)
  data = malloc (RSA_size (sent_key));
  if (!data)
    {
      log_error ("rsa_sig_encode_hash: malloc (%d) failed",
		 RSA_size (sent_key));
      return -1;
    }

  datalen = RSA_private_encrypt (hashsize, buf, data, sent_key,
				 RSA_PKCS1_PADDING);
#else
  datalen = monitor_RSA_private_encrypt (hashsize, buf, &data, sent_key,
					 RSA_PKCS1_PADDING);
#endif /* USE_PRIVSEP */
  if (datalen == -1)
    {
      log_print ("rsa_sig_encode_hash: RSA_private_encrypt () failed");
      if (data)
	free (data);
      free (buf);
      monitor_RSA_free (sent_key);
      return -1;
    }

  free (buf);

  buf = realloc (data, ISAKMP_SIG_SZ + datalen);
  if (!buf)
    {
      log_error ("rsa_sig_encode_hash: realloc (%p, %d) failed", data,
		 ISAKMP_SIG_SZ + datalen);
      free (data);
      return -1;
    }
  memmove (buf + ISAKMP_SIG_SZ, buf, datalen);

  snprintf (header, sizeof header, "rsa_sig_encode_hash: SIG_%c",
	    initiator ? 'I' : 'R');
  LOG_DBG_BUF ((LOG_MISC, 80, header, buf + ISAKMP_SIG_DATA_OFF, datalen));
  if (message_add_payload (msg, ISAKMP_PAYLOAD_SIG, buf,
			   ISAKMP_SIG_SZ + datalen, 1))
    {
      free (buf);
      return -1;
    }
  return 0;
}
#endif /* USE_X509 || USE_KEYNOTE */

int
ike_auth_hash (struct exchange *exchange, u_int8_t *buf)
{
  struct ipsec_exch *ie = exchange->data;
  struct prf *prf;
  struct hash *hash = ie->hash;
  int initiator = exchange->initiator;
  u_int8_t *id;
  size_t id_len;

  /* Choose the right fields to fill-in.  */
  id = initiator ? exchange->id_i : exchange->id_r;
  id_len = initiator ? exchange->id_i_len : exchange->id_r_len;

  /* Allocate the prf and start calculating our HASH.  */
  prf = prf_alloc (ie->prf_type, hash->type, ie->skeyid, ie->skeyid_len);
  if (!prf)
    return -1;

  prf->Init (prf->prfctx);
  prf->Update (prf->prfctx, initiator ? ie->g_xi : ie->g_xr, ie->g_x_len);
  prf->Update (prf->prfctx, initiator ? ie->g_xr : ie->g_xi, ie->g_x_len);
  prf->Update (prf->prfctx,
	       exchange->cookies
	       + (initiator ? ISAKMP_HDR_ICOOKIE_OFF : ISAKMP_HDR_RCOOKIE_OFF),
	       ISAKMP_HDR_ICOOKIE_LEN);
  prf->Update (prf->prfctx,
	       exchange->cookies
	       + (initiator ? ISAKMP_HDR_RCOOKIE_OFF : ISAKMP_HDR_ICOOKIE_OFF),
	       ISAKMP_HDR_ICOOKIE_LEN);
  prf->Update (prf->prfctx, ie->sa_i_b, ie->sa_i_b_len);
  prf->Update (prf->prfctx, id, id_len);
  prf->Final (buf, prf->prfctx);
  prf_free (prf);

  return 0;
}

#if defined (USE_RAWKEY)
static int
get_raw_key_from_file (int type, u_int8_t *id, size_t id_len, RSA **rsa)
{
  char filename[FILENAME_MAX];
  char *fstr;
  struct stat st;
  BIO *bio;

  if (type != IKE_AUTH_RSA_SIG) /* XXX More types? */
    {
      LOG_DBG ((LOG_NEGOTIATION, 20, "get_raw_key_from_file: "
		"invalid auth type %d\n", type));
      return -1;
    }

  *rsa = 0;

  fstr = conf_get_str ("General", "Pubkey-directory");
  if (!fstr)
    fstr = CONF_DFLT_PUBKEY_DIR;

  if (snprintf (filename, sizeof filename, "%s/", fstr) > sizeof filename - 1)
    return -1;

  fstr = ipsec_id_string (id, id_len);
  if (!fstr)
    {
      LOG_DBG ((LOG_NEGOTIATION, 50, "get_raw_key_from_file: "
		"ipsec_id_string failed"));
      return -1;
    }
  strlcat (filename, fstr, sizeof filename - strlen (filename));
  free (fstr);

  /* If the file does not exist, fail silently.  */
  if (stat (filename, &st) == 0)
    {
      bio = BIO_new (BIO_s_file ());
      if (!bio)
	{
	  log_error ("get_raw_key_from_file: could not initialize BIO");
	  return -1;
	}
      if (BIO_read_filename (bio, filename) <= 0)
	{
	  LOG_DBG((LOG_NEGOTIATION, 50, "get_raw_key_from_file: "
		   "BIO_read_filename(bio, \"%s\") failed", filename));
	  BIO_free (bio);
	  return -1;
	}
      LOG_DBG((LOG_NEGOTIATION, 80, "get_raw_key_from_file: reading file %s",
	       filename));
      *rsa = PEM_read_bio_RSA_PUBKEY (bio, NULL, NULL, NULL);
      BIO_free (bio);
    }
  else
    LOG_DBG((LOG_NEGOTIATION, 50, "get_raw_key_from_file: file %s not found",
	     filename));

  return (*rsa ? 0 : -1);
}
#endif /* USE_RAWKEY */