Пример #1
0
/*
 * Write a pubkey-enc packet for the public key PK to OUT.
 */
int
write_pubkey_enc (ctrl_t ctrl,
                  PKT_public_key *pk, int throw_keyid, DEK *dek, iobuf_t out)
{
  PACKET pkt;
  PKT_pubkey_enc *enc;
  int rc;
  gcry_mpi_t frame;

  print_pubkey_algo_note ( pk->pubkey_algo );
  enc = xmalloc_clear ( sizeof *enc );
  enc->pubkey_algo = pk->pubkey_algo;
  keyid_from_pk( pk, enc->keyid );
  enc->throw_keyid = throw_keyid;

  /* Okay, what's going on: We have the session key somewhere in
   * the structure DEK and want to encode this session key in an
   * integer value of n bits. pubkey_nbits gives us the number of
   * bits we have to use.  We then encode the session key in some
   * way and we get it back in the big intger value FRAME.  Then
   * we use FRAME, the public key PK->PKEY and the algorithm
   * number PK->PUBKEY_ALGO and pass it to pubkey_encrypt which
   * returns the encrypted value in the array ENC->DATA.  This
   * array has a size which depends on the used algorithm (e.g. 2
   * for Elgamal).  We don't need frame anymore because we have
   * everything now in enc->data which is the passed to
   * build_packet().  */
  frame = encode_session_key (pk->pubkey_algo, dek,
                              pubkey_nbits (pk->pubkey_algo, pk->pkey));
  rc = pk_encrypt (pk->pubkey_algo, enc->data, frame, pk, pk->pkey);
  gcry_mpi_release (frame);
  if (rc)
    log_error ("pubkey_encrypt failed: %s\n", gpg_strerror (rc) );
  else
    {
      if ( opt.verbose )
        {
          char *ustr = get_user_id_string_native (ctrl, enc->keyid);
          log_info (_("%s/%s.%s encrypted for: \"%s\"\n"),
                    openpgp_pk_algo_name (enc->pubkey_algo),
                    openpgp_cipher_algo_name (dek->algo),
                    dek->use_aead? openpgp_aead_algo_name (dek->use_aead)
                    /**/         : "CFB",
                    ustr );
          xfree (ustr);
        }
      /* And write it. */
      init_packet (&pkt);
      pkt.pkttype = PKT_PUBKEY_ENC;
      pkt.pkt.pubkey_enc = enc;
      rc = build_packet (out, &pkt);
      if (rc)
        log_error ("build_packet(pubkey_enc) failed: %s\n",
                   gpg_strerror (rc));
    }
  free_pubkey_enc(enc);
  return rc;
}
/****************
 * Write pubkey-enc packets from the list of PKs to OUT.
 */
static int
write_pubkey_enc_from_list( PK_LIST pk_list, DEK *dek, IOBUF out )
{
    PACKET pkt;
    PKT_public_key *pk;
    PKT_pubkey_enc  *enc;
    int rc;

    for( ; pk_list; pk_list = pk_list->next ) {
	MPI frame;

	pk = pk_list->pk;

	print_pubkey_algo_note( pk->pubkey_algo );
	enc = xmalloc_clear( sizeof *enc );
	enc->pubkey_algo = pk->pubkey_algo;
	keyid_from_pk( pk, enc->keyid );
	enc->throw_keyid = (opt.throw_keyid || (pk_list->flags&1));

	if(opt.throw_keyid && (PGP2 || PGP6 || PGP7 || PGP8))
	  {
	    log_info(_("you may not use %s while in %s mode\n"),
		     "--throw-keyid",compliance_option_string());
	    compliance_failure();
	  }

	/* Okay, what's going on: We have the session key somewhere in
	 * the structure DEK and want to encode this session key in
	 * an integer value of n bits.	pubkey_nbits gives us the
	 * number of bits we have to use.  We then encode the session
	 * key in some way and we get it back in the big intger value
	 * FRAME.  Then we use FRAME, the public key PK->PKEY and the
	 * algorithm number PK->PUBKEY_ALGO and pass it to pubkey_encrypt
	 * which returns the encrypted value in the array ENC->DATA.
	 * This array has a size which depends on the used algorithm
	 * (e.g. 2 for Elgamal).  We don't need frame anymore because we
	 * have everything now in enc->data which is the passed to
	 * build_packet()
	 */
	frame = encode_session_key( dek, pubkey_nbits( pk->pubkey_algo,
							  pk->pkey ) );
	rc = pubkey_encrypt( pk->pubkey_algo, enc->data, frame, pk->pkey );
	mpi_free( frame );
	if( rc )
	    log_error("pubkey_encrypt failed: %s\n", g10_errstr(rc) );
	else {
	    if( opt.verbose ) {
		char *ustr = get_user_id_string_native (enc->keyid);
		log_info(_("%s/%s encrypted for: \"%s\"\n"),
		    pubkey_algo_to_string(enc->pubkey_algo),
		    cipher_algo_to_string(dek->algo), ustr );
		xfree(ustr);
	    }
	    /* and write it */
	    init_packet(&pkt);
	    pkt.pkttype = PKT_PUBKEY_ENC;
	    pkt.pkt.pubkey_enc = enc;
	    rc = build_packet( out, &pkt );
	    if( rc )
	       log_error("build_packet(pubkey_enc) failed: %s\n", g10_errstr(rc));
	}
	free_pubkey_enc(enc);
	if( rc )
	    return rc;
    }
    return 0;
}