path: root/lib/opencdk/write-packet.c

/* write-packet.c - Write OpenPGP packets
 * Copyright (C) 2001-2003, 2007-2010, 2012 Free Software Foundation,
 * Inc.
 *
 * Author: Timo Schulz
 *
 * This file is part of OpenCDK.
 *
 * The OpenCDK library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 3 of
 * the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>
 *
 */
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <string.h>
#include <stdio.h>
#include <assert.h>

#include "opencdk.h"
#include "main.h"


static int
stream_write (cdk_stream_t s, const void *buf, size_t buflen)
{
  int nwritten;

  nwritten = cdk_stream_write (s, buf, buflen);
  if (nwritten == EOF)
    return _cdk_stream_get_errno (s);
  return 0;
}


static int
stream_read (cdk_stream_t s, void *buf, size_t buflen, size_t * r_nread)
{
  int nread;

  assert (r_nread);

  nread = cdk_stream_read (s, buf, buflen);
  if (nread == EOF)
    return _cdk_stream_get_errno (s);
  *r_nread = nread;
  return 0;
}


static int
stream_putc (cdk_stream_t s, int c)
{
  int nwritten = cdk_stream_putc (s, c);
  if (nwritten == EOF)
    return _cdk_stream_get_errno (s);
  return 0;
}


static int
write_32 (cdk_stream_t out, u32 u)
{
  byte buf[4];

  buf[0] = u >> 24;
  buf[1] = u >> 16;
  buf[2] = u >> 8;
  buf[3] = u;
  return stream_write (out, buf, 4);
}


static int
write_16 (cdk_stream_t out, u16 u)
{
  byte buf[2];

  buf[0] = u >> 8;
  buf[1] = u;
  return stream_write (out, buf, 2);
}


static size_t
calc_mpisize (bigint_t mpi[MAX_CDK_PK_PARTS], size_t ncount)
{
  size_t size, i;

  size = 0;
  for (i = 0; i < ncount; i++)
    size += (_gnutls_mpi_get_nbits (mpi[i]) + 7) / 8 + 2;
  return size;
}


static int
write_mpi (cdk_stream_t out, bigint_t m)
{
  byte buf[MAX_MPI_BYTES + 2];
  size_t nbits, nread;
  int err;

  if (!out || !m)
    return CDK_Inv_Value;
  nbits = _gnutls_mpi_get_nbits (m);
  if (nbits > MAX_MPI_BITS || nbits < 1)
    return CDK_MPI_Error;

  nread = MAX_MPI_BYTES + 2;
  err = _gnutls_mpi_print_pgp (m, buf, &nread);
  if (err < 0)
    return map_gnutls_error (err);
  return stream_write (out, buf, nread);
}


static cdk_error_t
write_mpibuf (cdk_stream_t out, bigint_t mpi[MAX_CDK_PK_PARTS], size_t count)
{
  size_t i;
  cdk_error_t rc;

  for (i = 0; i < count; i++)
    {
      rc = write_mpi (out, mpi[i]);
      if (rc)
        return rc;
    }
  return 0;
}


static cdk_error_t
pkt_encode_len (cdk_stream_t out, size_t pktlen)
{
  cdk_error_t rc;

  assert (out);

  rc = 0;
  if (!pktlen)
    {
      /* Block mode, partial bodies, with 'DEF_BLOCKSIZE' from main.h */
      rc = stream_putc (out, (0xE0 | DEF_BLOCKBITS));
    }
  else if (pktlen < 192)
    rc = stream_putc (out, pktlen);
  else if (pktlen < 8384)
    {
      pktlen -= 192;
      rc = stream_putc (out, (pktlen / 256) + 192);
      if (!rc)
        rc = stream_putc (out, (pktlen % 256));
    }
  else
    {
      rc = stream_putc (out, 255);
      if (!rc)
        rc = write_32 (out, pktlen);
    }

  return rc;
}


static cdk_error_t
write_head_new (cdk_stream_t out, size_t size, int type)
{
  cdk_error_t rc;

  assert (out);

  if (type < 0 || type > 63)
    return CDK_Inv_Packet;
  rc = stream_putc (out, (0xC0 | type));
  if (!rc)
    rc = pkt_encode_len (out, size);
  return rc;
}


static cdk_error_t
write_head_old (cdk_stream_t out, size_t size, int type)
{
  cdk_error_t rc;
  int ctb;

  assert (out);

  if (type < 0 || type > 16)
    return CDK_Inv_Packet;
  ctb = 0x80 | (type << 2);
  if (!size)
    ctb |= 3;
  else if (size < 256)
    ;
  else if (size < 65536)
    ctb |= 1;
  else
    ctb |= 2;
  rc = stream_putc (out, ctb);
  if (!size)
    return rc;
  if (!rc)
    {
      if (size < 256)
        rc = stream_putc (out, size);
      else if (size < 65536)
        rc = write_16 (out, size);
      else
        rc = write_32 (out, size);
    }

  return rc;
}


/* Write special PGP2 packet header. PGP2 (wrongly) uses two byte header
   length for signatures and keys even if the size is < 256. */
static cdk_error_t
pkt_write_head2 (cdk_stream_t out, size_t size, int type)
{
  cdk_error_t rc;

  rc = cdk_stream_putc (out, 0x80 | (type << 2) | 1);
  if (!rc)
    rc = cdk_stream_putc (out, size >> 8);
  if (!rc)
    rc = cdk_stream_putc (out, size & 0xff);
  return rc;
}


static int
pkt_write_head (cdk_stream_t out, int old_ctb, size_t size, int type)
{
  if (old_ctb)
    return write_head_old (out, size, type);
  return write_head_new (out, size, type);
}


static int
write_pubkey_enc (cdk_stream_t out, cdk_pkt_pubkey_enc_t pke, int old_ctb)
{
  size_t size;
  int rc, nenc;

  assert (out);
  assert (pke);

  if (pke->version < 2 || pke->version > 3)
    return CDK_Inv_Packet;
  if (!KEY_CAN_ENCRYPT (pke->pubkey_algo))
    return CDK_Inv_Algo;

  if (DEBUG_PKT)
    _gnutls_write_log ("write_pubkey_enc:\n");

  nenc = cdk_pk_get_nenc (pke->pubkey_algo);
  size = 10 + calc_mpisize (pke->mpi, nenc);
  rc = pkt_write_head (out, old_ctb, size, CDK_PKT_PUBKEY_ENC);
  if (rc)
    return rc;

  rc = stream_putc (out, pke->version);
  if (!rc)
    rc = write_32 (out, pke->keyid[0]);
  if (!rc)
    rc = write_32 (out, pke->keyid[1]);
  if (!rc)
    rc = stream_putc (out, _cdk_pub_algo_to_pgp (pke->pubkey_algo));
  if (!rc)
    rc = write_mpibuf (out, pke->mpi, nenc);
  return rc;
}


static cdk_error_t
write_mdc (cdk_stream_t out, cdk_pkt_mdc_t mdc)
{
  cdk_error_t rc;

  assert (mdc);
  assert (out);

  if (DEBUG_PKT)
    _gnutls_write_log ("write_mdc:\n");

  /* This packet requires a fixed header encoding */
  rc = stream_putc (out, 0xD3); /* packet ID and 1 byte length */
  if (!rc)
    rc = stream_putc (out, 0x14);
  if (!rc)
    rc = stream_write (out, mdc->hash, DIM (mdc->hash));
  return rc;
}


static size_t
calc_subpktsize (cdk_subpkt_t s)
{
  size_t nbytes;

  /* In the count mode, no buffer is returned. */
  _cdk_subpkt_get_array (s, 1, &nbytes);
  return nbytes;
}


static cdk_error_t
write_v3_sig (cdk_stream_t out, cdk_pkt_signature_t sig, int nsig)
{
  size_t size;
  cdk_error_t rc;

  size = 19 + calc_mpisize (sig->mpi, nsig);
  if (is_RSA (sig->pubkey_algo))
    rc = pkt_write_head2 (out, size, CDK_PKT_SIGNATURE);
  else
    rc = pkt_write_head (out, 1, size, CDK_PKT_SIGNATURE);
  if (!rc)
    rc = stream_putc (out, sig->version);
  if (!rc)
    rc = stream_putc (out, 5);
  if (!rc)
    rc = stream_putc (out, sig->sig_class);
  if (!rc)
    rc = write_32 (out, sig->timestamp);
  if (!rc)
    rc = write_32 (out, sig->keyid[0]);
  if (!rc)
    rc = write_32 (out, sig->keyid[1]);
  if (!rc)
    rc = stream_putc (out, _cdk_pub_algo_to_pgp (sig->pubkey_algo));
  if (!rc)
    rc = stream_putc (out, _gnutls_hash_algo_to_pgp (sig->digest_algo));
  if (!rc)
    rc = stream_putc (out, sig->digest_start[0]);
  if (!rc)
    rc = stream_putc (out, sig->digest_start[1]);
  if (!rc)
    rc = write_mpibuf (out, sig->mpi, nsig);
  return rc;
}


static cdk_error_t
write_signature (cdk_stream_t out, cdk_pkt_signature_t sig, int old_ctb)
{
  byte *buf;
  size_t nbytes, size, nsig;
  cdk_error_t rc;

  assert (out);
  assert (sig);

  if (!KEY_CAN_SIGN (sig->pubkey_algo))
    return CDK_Inv_Algo;
  if (sig->version < 2 || sig->version > 4)
    return CDK_Inv_Packet;

  if (DEBUG_PKT)
    _gnutls_write_log ("write_signature:\n");

  nsig = cdk_pk_get_nsig (sig->pubkey_algo);
  if (!nsig)
    return CDK_Inv_Algo;
  if (sig->version < 4)
    return write_v3_sig (out, sig, nsig);

  size = 10 + calc_subpktsize (sig->hashed)
    + calc_subpktsize (sig->unhashed) + calc_mpisize (sig->mpi, nsig);
  rc = pkt_write_head (out, 0, size, CDK_PKT_SIGNATURE);
  if (!rc)
    rc = stream_putc (out, 4);
  if (!rc)
    rc = stream_putc (out, sig->sig_class);
  if (!rc)
    rc = stream_putc (out, _cdk_pub_algo_to_pgp (sig->pubkey_algo));
  if (!rc)
    rc = stream_putc (out, _gnutls_hash_algo_to_pgp (sig->digest_algo));
  if (!rc)
    rc = write_16 (out, sig->hashed_size);
  if (!rc)
    {
      buf = _cdk_subpkt_get_array (sig->hashed, 0, &nbytes);
      if (!buf)
        return CDK_Out_Of_Core;
      rc = stream_write (out, buf, nbytes);
      cdk_free (buf);
    }
  if (!rc)
    rc = write_16 (out, sig->unhashed_size);
  if (!rc)
    {
      buf = _cdk_subpkt_get_array (sig->unhashed, 0, &nbytes);
      if (!buf)
        return CDK_Out_Of_Core;
      rc = stream_write (out, buf, nbytes);
      cdk_free (buf);
    }
  if (!rc)
    rc = stream_putc (out, sig->digest_start[0]);
  if (!rc)
    rc = stream_putc (out, sig->digest_start[1]);
  if (!rc)
    rc = write_mpibuf (out, sig->mpi, nsig);
  return rc;
}


static cdk_error_t
write_public_key (cdk_stream_t out, cdk_pkt_pubkey_t pk,
                  int is_subkey, int old_ctb)
{
  int pkttype, ndays = 0;
  size_t npkey = 0, size = 6;
  cdk_error_t rc;

  assert (out);
  assert (pk);

  if (pk->version < 2 || pk->version > 4)
    return CDK_Inv_Packet;

  if (DEBUG_PKT)
    _gnutls_write_log ("write_public_key: subkey=%d\n", is_subkey);

  pkttype = is_subkey ? CDK_PKT_PUBLIC_SUBKEY : CDK_PKT_PUBLIC_KEY;
  npkey = cdk_pk_get_npkey (pk->pubkey_algo);
  if (!npkey)
    return CDK_Inv_Algo;
  if (pk->version < 4)
    size += 2;                  /* expire date */
  if (is_subkey)
    old_ctb = 0;
  size += calc_mpisize (pk->mpi, npkey);
  if (old_ctb)
    rc = pkt_write_head2 (out, size, pkttype);
  else
    rc = pkt_write_head (out, old_ctb, size, pkttype);
  if (!rc)
    rc = stream_putc (out, pk->version);
  if (!rc)
    rc = write_32 (out, pk->timestamp);
  if (!rc && pk->version < 4)
    {
      if (pk->expiredate)
        ndays = (u16) ((pk->expiredate - pk->timestamp) / 86400L);
      rc = write_16 (out, ndays);
    }
  if (!rc)
    rc = stream_putc (out, _cdk_pub_algo_to_pgp (pk->pubkey_algo));
  if (!rc)
    rc = write_mpibuf (out, pk->mpi, npkey);
  return rc;
}


static int
calc_s2ksize (cdk_pkt_seckey_t sk)
{
  size_t nbytes = 0;

  if (!sk->is_protected)
    return 0;
  switch (sk->protect.s2k->mode)
    {
    case CDK_S2K_SIMPLE:
      nbytes = 2;
      break;
    case CDK_S2K_SALTED:
      nbytes = 10;
      break;
    case CDK_S2K_ITERSALTED:
      nbytes = 11;
      break;
    }
  nbytes += sk->protect.ivlen;
  nbytes++;                     /* single cipher byte */
  return nbytes;
}


static cdk_error_t
write_secret_key (cdk_stream_t out, cdk_pkt_seckey_t sk,
                  int is_subkey, int old_ctb)
{
  cdk_pkt_pubkey_t pk = NULL;
  size_t size = 6, npkey, nskey;
  int pkttype, s2k_mode;
  cdk_error_t rc;

  assert (out);
  assert (sk);

  if (!sk->pk)
    return CDK_Inv_Value;
  pk = sk->pk;
  if (pk->version < 2 || pk->version > 4)
    return CDK_Inv_Packet;

  if (DEBUG_PKT)
    _gnutls_write_log ("write_secret_key:\n");

  npkey = cdk_pk_get_npkey (pk->pubkey_algo);
  nskey = cdk_pk_get_nskey (pk->pubkey_algo);
  if (!npkey || !nskey)
    {
      gnutls_assert ();
      return CDK_Inv_Algo;
    }
  if (pk->version < 4)
    size += 2;
  /* If the key is unprotected, the 1 extra byte:
     1 octet  - cipher algorithm byte (0x00)
     the other bytes depend on the mode:
     a) simple checksum -  2 octets
     b) sha-1 checksum  - 20 octets */
  size = !sk->is_protected ? size + 1 : size + 1 + calc_s2ksize (sk);
  size += calc_mpisize (pk->mpi, npkey);
  if (sk->version == 3 || !sk->is_protected)
    {
      if (sk->version == 3)
        {
          size += 2;            /* force simple checksum */
          sk->protect.sha1chk = 0;
        }
      else
        size += sk->protect.sha1chk ? 20 : 2;
      size += calc_mpisize (sk->mpi, nskey);
    }
  else                          /* We do not know anything about the encrypted mpi's so we
                                   treat the data as opaque. */
    size += sk->enclen;

  pkttype = is_subkey ? CDK_PKT_SECRET_SUBKEY : CDK_PKT_SECRET_KEY;
  rc = pkt_write_head (out, old_ctb, size, pkttype);
  if (!rc)
    rc = stream_putc (out, pk->version);
  if (!rc)
    rc = write_32 (out, pk->timestamp);
  if (!rc && pk->version < 4)
    {
      u16 ndays = 0;
      if (pk->expiredate)
        ndays = (u16) ((pk->expiredate - pk->timestamp) / 86400L);
      rc = write_16 (out, ndays);
    }
  if (!rc)
    rc = stream_putc (out, _cdk_pub_algo_to_pgp (pk->pubkey_algo));

  if (!rc)
    rc = write_mpibuf (out, pk->mpi, npkey);

  if (!rc)
    {
      if (sk->is_protected == 0)
        rc = stream_putc (out, 0x00);
      else
        {
          if (is_RSA (pk->pubkey_algo) && pk->version < 4)
            rc = stream_putc (out, _gnutls_cipher_to_pgp (sk->protect.algo));
          else if (sk->protect.s2k)
            {
              s2k_mode = sk->protect.s2k->mode;
              rc = stream_putc (out, sk->protect.sha1chk ? 0xFE : 0xFF);
              if (!rc)
                rc =
                  stream_putc (out, _gnutls_cipher_to_pgp (sk->protect.algo));
              if (!rc)
                rc = stream_putc (out, sk->protect.s2k->mode);
              if (!rc)
                rc = stream_putc (out, sk->protect.s2k->hash_algo);
              if (!rc && (s2k_mode == 1 || s2k_mode == 3))
                {
                  rc = stream_write (out, sk->protect.s2k->salt, 8);
                  if (!rc && s2k_mode == 3)
                    rc = stream_putc (out, sk->protect.s2k->count);
                }
            }
          else
            return CDK_Inv_Value;
          if (!rc)
            rc = stream_write (out, sk->protect.iv, sk->protect.ivlen);
        }
    }
  if (!rc && sk->is_protected && pk->version == 4)
    {
      if (sk->encdata && sk->enclen)
        rc = stream_write (out, sk->encdata, sk->enclen);
    }
  else
    {
      if (!rc)
        rc = write_mpibuf (out, sk->mpi, nskey);
      if (!rc)
        {
          if (!sk->csum)
            sk->csum = _cdk_sk_get_csum (sk);
          rc = write_16 (out, sk->csum);
        }
    }

  return rc;
}


static cdk_error_t
write_compressed (cdk_stream_t out, cdk_pkt_compressed_t cd)
{
  cdk_error_t rc;

  assert (out);
  assert (cd);

  if (DEBUG_PKT)
    _gnutls_write_log ("packet: write_compressed\n");

  /* Use an old (RFC1991) header for this packet. */
  rc = pkt_write_head (out, 1, 0, CDK_PKT_COMPRESSED);
  if (!rc)
    rc = stream_putc (out, cd->algorithm);
  return rc;
}


static cdk_error_t
write_literal (cdk_stream_t out, cdk_pkt_literal_t pt, int old_ctb)
{
  byte buf[BUFSIZE];
  size_t size;
  cdk_error_t rc;

  assert (out);
  assert (pt);

  /* We consider a packet without a body as an invalid packet.
     At least one octet must be present. */
  if (!pt->len)
    return CDK_Inv_Packet;

  if (DEBUG_PKT)
    _gnutls_write_log ("write_literal:\n");

  size = 6 + pt->namelen + pt->len;
  rc = pkt_write_head (out, old_ctb, size, CDK_PKT_LITERAL);
  if (rc)
    return rc;

  rc = stream_putc (out, pt->mode);
  if (rc)
    return rc;
  rc = stream_putc (out, pt->namelen);
  if (rc)
    return rc;

  if (pt->namelen > 0)
    rc = stream_write (out, pt->name, pt->namelen);
  if (!rc)
    rc = write_32 (out, pt->timestamp);
  if (rc)
    return rc;

  while (!cdk_stream_eof (pt->buf) && !rc)
    {
      rc = stream_read (pt->buf, buf, DIM (buf), &size);
      if (!rc)
        rc = stream_write (out, buf, size);
    }

  memset (buf, 0, sizeof (buf));
  return rc;
}


static cdk_error_t
write_onepass_sig (cdk_stream_t out, cdk_pkt_onepass_sig_t sig)
{
  cdk_error_t rc;

  assert (out);
  assert (sig);

  if (sig->version != 3)
    return CDK_Inv_Packet;

  if (DEBUG_PKT)
    _gnutls_write_log ("write_onepass_sig:\n");

  rc = pkt_write_head (out, 0, 13, CDK_PKT_ONEPASS_SIG);
  if (!rc)
    rc = stream_putc (out, sig->version);
  if (!rc)
    rc = stream_putc (out, sig->sig_class);
  if (!rc)
    rc = stream_putc (out, _gnutls_hash_algo_to_pgp (sig->digest_algo));
  if (!rc)
    rc = stream_putc (out, _cdk_pub_algo_to_pgp (sig->pubkey_algo));
  if (!rc)
    rc = write_32 (out, sig->keyid[0]);
  if (!rc)
    rc = write_32 (out, sig->keyid[1]);
  if (!rc)
    rc = stream_putc (out, sig->last);
  return rc;
}


static cdk_error_t
write_user_id (cdk_stream_t out, cdk_pkt_userid_t id, int old_ctb,
               int pkttype)
{
  cdk_error_t rc;

  if (!out || !id)
    return CDK_Inv_Value;

  if (pkttype == CDK_PKT_ATTRIBUTE)
    {
      if (!id->attrib_img)
        return CDK_Inv_Value;
      rc =
        pkt_write_head (out, old_ctb, id->attrib_len + 6, CDK_PKT_ATTRIBUTE);
      if (rc)
        return rc;
      /* Write subpacket part. */
      stream_putc (out, 255);
      write_32 (out, id->attrib_len + 1);
      stream_putc (out, 1);
      rc = stream_write (out, id->attrib_img, id->attrib_len);
    }
  else
    {
      if (!id->name)
        return CDK_Inv_Value;
      rc = pkt_write_head (out, old_ctb, id->len, CDK_PKT_USER_ID);
      if (!rc)
        rc = stream_write (out, id->name, id->len);
    }

  return rc;
}


/**
 * cdk_pkt_write:
 * @out: the output stream handle
 * @pkt: the packet itself
 *
 * Write the contents of @pkt into the @out stream.
 * Return 0 on success.
 **/
cdk_error_t
cdk_pkt_write (cdk_stream_t out, cdk_packet_t pkt)
{
  cdk_error_t rc;

  if (!out || !pkt)
    return CDK_Inv_Value;

  _gnutls_write_log ("write packet pkttype=%d\n", pkt->pkttype);
  switch (pkt->pkttype)
    {
    case CDK_PKT_LITERAL:
      rc = write_literal (out, pkt->pkt.literal, pkt->old_ctb);
      break;
    case CDK_PKT_ONEPASS_SIG:
      rc = write_onepass_sig (out, pkt->pkt.onepass_sig);
      break;
    case CDK_PKT_MDC:
      rc = write_mdc (out, pkt->pkt.mdc);
      break;
    case CDK_PKT_PUBKEY_ENC:
      rc = write_pubkey_enc (out, pkt->pkt.pubkey_enc, pkt->old_ctb);
      break;
    case CDK_PKT_SIGNATURE:
      rc = write_signature (out, pkt->pkt.signature, pkt->old_ctb);
      break;
    case CDK_PKT_PUBLIC_KEY:
      rc = write_public_key (out, pkt->pkt.public_key, 0, pkt->old_ctb);
      break;
    case CDK_PKT_PUBLIC_SUBKEY:
      rc = write_public_key (out, pkt->pkt.public_key, 1, pkt->old_ctb);
      break;
    case CDK_PKT_COMPRESSED:
      rc = write_compressed (out, pkt->pkt.compressed);
      break;
    case CDK_PKT_SECRET_KEY:
      rc = write_secret_key (out, pkt->pkt.secret_key, 0, pkt->old_ctb);
      break;
    case CDK_PKT_SECRET_SUBKEY:
      rc = write_secret_key (out, pkt->pkt.secret_key, 1, pkt->old_ctb);
      break;
    case CDK_PKT_USER_ID:
    case CDK_PKT_ATTRIBUTE:
      rc = write_user_id (out, pkt->pkt.user_id, pkt->old_ctb, pkt->pkttype);
      break;
    default:
      rc = CDK_Inv_Packet;
      break;
    }

  if (DEBUG_PKT)
    _gnutls_write_log ("write_packet rc=%d pkttype=%d\n", rc, pkt->pkttype);
  return rc;
}


cdk_error_t
_cdk_pkt_write2 (cdk_stream_t out, int pkttype, void *pktctx)
{
  cdk_packet_t pkt;
  cdk_error_t rc;

  rc = cdk_pkt_new (&pkt);
  if (rc)
    return rc;

  switch (pkttype)
    {
    case CDK_PKT_PUBLIC_KEY:
    case CDK_PKT_PUBLIC_SUBKEY:
      pkt->pkt.public_key = pktctx;
      break;
    case CDK_PKT_SIGNATURE:
      pkt->pkt.signature = pktctx;
      break;
    case CDK_PKT_SECRET_KEY:
    case CDK_PKT_SECRET_SUBKEY:
      pkt->pkt.secret_key = pktctx;
      break;

    case CDK_PKT_USER_ID:
      pkt->pkt.user_id = pktctx;
      break;
    }
  pkt->pkttype = pkttype;
  rc = cdk_pkt_write (out, pkt);
  cdk_free (pkt);
  return rc;
}


cdk_error_t
_cdk_pkt_write_fp (FILE * out, cdk_packet_t pkt)
{
  cdk_stream_t so;
  cdk_error_t rc;

  rc = _cdk_stream_fpopen (out, 1, &so);
  if (rc)
    return rc;
  rc = cdk_pkt_write (so, pkt);
  cdk_stream_close (so);
  return rc;
}