path: root/lib/opencdk/kbnode.c

/* kbnode.c -  keyblock node utility functions
 * Copyright (C) 1998-2012 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 <stdio.h>
#include <stdlib.h>
#include <string.h>

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


/**
 * cdk_kbnode_new:
 * @pkt: the packet to add
 *
 * Allocates a new key node and adds a packet.
 **/
cdk_kbnode_t
cdk_kbnode_new (cdk_packet_t pkt)
{
  cdk_kbnode_t n;

  n = cdk_calloc (1, sizeof *n);
  if (!n)
    return NULL;
  n->pkt = pkt;
  return n;
}


void
_cdk_kbnode_clone (cdk_kbnode_t node)
{
  /* Mark the node as clone which means that the packet
     will not be freed, just the node itself. */
  if (node)
    node->is_cloned = 1;
}


/**
 * cdk_kbnode_release:
 * @n: the key node
 *
 * Releases the memory of the node.
 **/
void
cdk_kbnode_release (cdk_kbnode_t node)
{
  cdk_kbnode_t n2;

  while (node)
    {
      n2 = node->next;
      if (!node->is_cloned)
        cdk_pkt_release (node->pkt);
      cdk_free (node);
      node = n2;
    }
}


/**
 * cdk_kbnode_delete:
 * @node: the key node
 *
 * Marks the given node as deleted.
 **/
void
cdk_kbnode_delete (cdk_kbnode_t node)
{
  if (node)
    node->is_deleted = 1;
}


/* Append NODE to ROOT.  ROOT must exist! */
void
_cdk_kbnode_add (cdk_kbnode_t root, cdk_kbnode_t node)
{
  cdk_kbnode_t n1;

  for (n1 = root; n1->next; n1 = n1->next)
    ;
  n1->next = node;
}


/**
 * cdk_kbnode_insert:
 * @root: the root key node
 * @node: the node to add
 * @pkttype: packet type
 *
 * Inserts @node into the list after @root but before a packet which is not of
 * type @pkttype (only if @pkttype != 0).
 **/
void
cdk_kbnode_insert (cdk_kbnode_t root, cdk_kbnode_t node,
                   cdk_packet_type_t pkttype)
{
  if (!pkttype)
    {
      node->next = root->next;
      root->next = node;
    }
  else
    {
      cdk_kbnode_t n1;

      for (n1 = root; n1->next; n1 = n1->next)
        if (pkttype != n1->next->pkt->pkttype)
          {
            node->next = n1->next;
            n1->next = node;
            return;
          }
      /* No such packet, append */
      node->next = NULL;
      n1->next = node;
    }
}


/**
 * cdk_kbnode_find_prev:
 * @root: the root key node
 * @node: the key node
 * @pkttype: packet type
 *
 * Finds the previous node (if @pkttype = 0) or the previous node
 * with pkttype @pkttype in the list starting with @root of @node.
 **/
cdk_kbnode_t
cdk_kbnode_find_prev (cdk_kbnode_t root, cdk_kbnode_t node,
                      cdk_packet_type_t pkttype)
{
  cdk_kbnode_t n1;

  for (n1 = NULL; root && root != node; root = root->next)
    {
      if (!pkttype || root->pkt->pkttype == pkttype)
        n1 = root;
    }
  return n1;
}


/**
 * cdk_kbnode_find_next:
 * @node: the key node
 * @pkttype: packet type
 *
 * Ditto, but find the next packet.  The behaviour is trivial if
 * @pkttype is 0 but if it is specified, the next node with a packet
 * of this type is returned.  The function has some knowledge about
 * the valid ordering of packets: e.g. if the next signature packet
 * is requested, the function will not return one if it encounters
 * a user-id.
 **/
cdk_kbnode_t
cdk_kbnode_find_next (cdk_kbnode_t node, cdk_packet_type_t pkttype)
{
  for (node = node->next; node; node = node->next)
    {
      if (!pkttype)
        return node;
      else if (pkttype == CDK_PKT_USER_ID &&
               (node->pkt->pkttype == CDK_PKT_PUBLIC_KEY ||
                node->pkt->pkttype == CDK_PKT_SECRET_KEY))
        return NULL;
      else if (pkttype == CDK_PKT_SIGNATURE &&
               (node->pkt->pkttype == CDK_PKT_USER_ID ||
                node->pkt->pkttype == CDK_PKT_PUBLIC_KEY ||
                node->pkt->pkttype == CDK_PKT_SECRET_KEY))
        return NULL;
      else if (node->pkt->pkttype == pkttype)
        return node;
    }
  return NULL;
}


/**
 * cdk_kbnode_find:
 * @node: the key node
 * @pkttype: packet type
 *
 * Tries to find the next node with the packettype @pkttype.
 **/
cdk_kbnode_t
cdk_kbnode_find (cdk_kbnode_t node, cdk_packet_type_t pkttype)
{
  for (; node; node = node->next)
    {
      if (node->pkt->pkttype == pkttype)
        return node;
    }
  return NULL;
}


/**
 * cdk_kbnode_find_packet:
 * @node: the key node
 * @pkttype: packet type
 *
 * Same as cdk_kbnode_find but it returns the packet instead of the node.
 **/
cdk_packet_t
cdk_kbnode_find_packet (cdk_kbnode_t node, cdk_packet_type_t pkttype)
{
  cdk_kbnode_t res;

  res = cdk_kbnode_find (node, pkttype);
  return res ? res->pkt : NULL;
}


/**
 * cdk_kbnode_walk:
 * 
 * Walks through a list of kbnodes. This function returns
 * the next kbnode for each call; before using the function the first
 * time, the caller must set CONTEXT to NULL (This has simply the effect
 * to start with ROOT).
 */
cdk_kbnode_t
cdk_kbnode_walk (cdk_kbnode_t root, cdk_kbnode_t * ctx, int all)
{
  cdk_kbnode_t n;

  do
    {
      if (!*ctx)
        {
          *ctx = root;
          n = root;
        }
      else
        {
          n = (*ctx)->next;
          *ctx = n;
        }
    }
  while (!all && n && n->is_deleted);
  return n;
}


/**
 * cdk_kbnode_commit:
 * @root: the nodes
 * 
 * Commits changes made to the kblist at ROOT. Note that ROOT my change,
 * and it is therefore passed by reference.
 * The function has the effect of removing all nodes marked as deleted.
 *
 * Returns: true if any node has been changed
 */
int
cdk_kbnode_commit (cdk_kbnode_t * root)
{
  cdk_kbnode_t n, nl;
  int changed = 0;

  for (n = *root, nl = NULL; n; n = nl->next)
    {
      if (n->is_deleted)
        {
          if (n == *root)
            *root = nl = n->next;
          else
            nl->next = n->next;
          if (!n->is_cloned)
            cdk_pkt_release (n->pkt);
          cdk_free (n);
          changed = 1;
        }
      else
        nl = n;
    }
  return changed;
}


/**
 * cdk_kbnode_remove:
 * @root: the root node
 * @node: the node to delete
 * 
 * Removes a node from the root node.
 */
void
cdk_kbnode_remove (cdk_kbnode_t * root, cdk_kbnode_t node)
{
  cdk_kbnode_t n, nl;

  for (n = *root, nl = NULL; n; n = nl->next)
    {
      if (n == node)
        {
          if (n == *root)
            *root = nl = n->next;
          else
            nl->next = n->next;
          if (!n->is_cloned)
            cdk_pkt_release (n->pkt);
          cdk_free (n);
        }
      else
        nl = n;
    }
}



/**
 * cdk_cdknode_move:
 * @root: root node
 * @node: the node to move
 * @where: destination place where to move the node.
 * 
 * Moves NODE behind right after WHERE or to the beginning if WHERE is NULL.
 */
void
cdk_kbnode_move (cdk_kbnode_t * root, cdk_kbnode_t node, cdk_kbnode_t where)
{
  cdk_kbnode_t tmp, prev;

  if (!root || !*root || !node)
    return;
  for (prev = *root; prev && prev->next != node; prev = prev->next)
    ;
  if (!prev)
    return;                     /* Node is not in the list */

  if (!where)
    {                           /* Move node before root */
      if (node == *root)
        return;
      prev->next = node->next;
      node->next = *root;
      *root = node;
      return;
    }
  if (node == where)            /* Move it after where. */
    return;
  tmp = node->next;
  node->next = where->next;
  where->next = node;
  prev->next = tmp;
}


/**
 * cdk_kbnode_get_packet:
 * @node: the key node
 *
 * Get packet in node.
 *
 * Returns: the packet which is stored inside the node in @node.
 **/
cdk_packet_t
cdk_kbnode_get_packet (cdk_kbnode_t node)
{
  if (node)
    return node->pkt;
  return NULL;
}


/**
 * cdk_kbnode_read_from_mem:
 * @ret_node: the new key node
 * @armor: whether base64 or not
 * @buf: the buffer which stores the key sequence
 * @buflen: the length of the buffer
 *
 * Tries to read a key node from the memory buffer @buf.
 **/
cdk_error_t
cdk_kbnode_read_from_mem (cdk_kbnode_t * ret_node,
                          int armor,
                          const byte * buf, size_t buflen)
{
  cdk_stream_t inp;
  cdk_error_t rc;

  if (!ret_node || !buf)
    return CDK_Inv_Value;

  *ret_node = NULL;
  if (!buflen)
    return gnutls_assert_val(CDK_Too_Short);

  rc = cdk_stream_tmp_from_mem (buf, buflen, &inp);
  if (rc)
    return gnutls_assert_val(rc);
  
  if (armor)
    cdk_stream_set_armor_flag (inp, 0);

  rc = cdk_keydb_get_keyblock (inp, ret_node);
  if (rc)
    gnutls_assert ();
  cdk_stream_close (inp);
  return rc;
}


/**
 * cdk_kbnode_write_to_mem_alloc:
 * @node: the key node
 * @r_buf: buffer to hold the raw data
 * @r_buflen: buffer length of the allocated raw data.
 * 
 * The function acts similar to cdk_kbnode_write_to_mem but
 * it allocates the buffer to avoid the lengthy second run.
 */
cdk_error_t
cdk_kbnode_write_to_mem_alloc (cdk_kbnode_t node,
                               byte ** r_buf, size_t * r_buflen)
{
  cdk_kbnode_t n;
  cdk_stream_t s;
  cdk_error_t rc;
  size_t len;

  if (!node || !r_buf || !r_buflen)
    {
      gnutls_assert ();
      return CDK_Inv_Value;
    }

  *r_buf = NULL;
  *r_buflen = 0;

  rc = cdk_stream_tmp_new (&s);
  if (rc)
    {
      gnutls_assert ();
      return rc;
    }

  for (n = node; n; n = n->next)
    {
      /* Skip all packets which cannot occur in a key composition. */
      if (n->pkt->pkttype != CDK_PKT_PUBLIC_KEY &&
          n->pkt->pkttype != CDK_PKT_PUBLIC_SUBKEY &&
          n->pkt->pkttype != CDK_PKT_SECRET_KEY &&
          n->pkt->pkttype != CDK_PKT_SECRET_SUBKEY &&
          n->pkt->pkttype != CDK_PKT_SIGNATURE &&
          n->pkt->pkttype != CDK_PKT_USER_ID &&
          n->pkt->pkttype != CDK_PKT_ATTRIBUTE)
        continue;
      rc = cdk_pkt_write (s, n->pkt);
      if (rc)
        {
          cdk_stream_close (s);
          gnutls_assert ();
          return rc;
        }
    }

  cdk_stream_seek (s, 0);
  len = cdk_stream_get_length (s);
  *r_buf = cdk_calloc (1, len);
  *r_buflen = cdk_stream_read (s, *r_buf, len);
  cdk_stream_close (s);
  return 0;
}


/**
 * cdk_kbnode_write_to_mem:
 * @node: the key node
 * @buf: the buffer to store the node data
 * @r_nbytes: the new length of the buffer.
 *
 * Tries to write the contents of the key node to the buffer @buf and
 * return the length of it in @r_nbytes. If buf is (0), only the
 * length of the node is calculated and returned in @r_nbytes.
 * Whenever it is possible, the cdk_kbnode_write_to_mem_alloc should be used.
 **/
cdk_error_t
cdk_kbnode_write_to_mem (cdk_kbnode_t node, byte * buf, size_t * r_nbytes)
{
  cdk_kbnode_t n;
  cdk_stream_t s;
  cdk_error_t rc;
  size_t len;

  if (!node || !r_nbytes)
    {
      gnutls_assert ();
      return CDK_Inv_Value;
    }

  rc = cdk_stream_tmp_new (&s);
  if (rc)
    {
      gnutls_assert ();
      return rc;
    }

  for (n = node; n; n = n->next)
    {
      /* Skip all packets which cannot occur in a key composition. */
      if (n->pkt->pkttype != CDK_PKT_PUBLIC_KEY &&
          n->pkt->pkttype != CDK_PKT_PUBLIC_SUBKEY &&
          n->pkt->pkttype != CDK_PKT_SECRET_KEY &&
          n->pkt->pkttype != CDK_PKT_SECRET_SUBKEY &&
          n->pkt->pkttype != CDK_PKT_SIGNATURE &&
          n->pkt->pkttype != CDK_PKT_USER_ID &&
          n->pkt->pkttype != CDK_PKT_ATTRIBUTE)
        continue;
      rc = cdk_pkt_write (s, n->pkt);
      if (rc)
        {
          cdk_stream_close (s);
          gnutls_assert ();
          return rc;
        }
    }

  cdk_stream_seek (s, 0);
  len = cdk_stream_get_length (s);
  if (!buf)
    {
      *r_nbytes = len;          /* Only return the length of the buffer */
      cdk_stream_close (s);
      return 0;
    }
  if (*r_nbytes < len)
    {
      *r_nbytes = len;
      rc = CDK_Too_Short;
    }
  if (!rc)
    *r_nbytes = cdk_stream_read (s, buf, len);
  else
    gnutls_assert ();
  cdk_stream_close (s);
  return rc;
}


/**
 * cdk_kbnode_hash:
 * @node: the key node
 * @hashctx: uint8_t pointer to the hash context
 * @is_v4: OpenPGP signature (yes=1, no=0)
 * @pkttype: packet type to hash (if (0) use the packet type from the node)
 * @flags: flags which depend on the operation
 *
 * Hashes the key node contents. Two modes are supported. If the packet
 * type is used (!= 0) then the function searches the first node with
 * this type. Otherwise the node is seen as a single node and the type
 * is extracted from it.
 **/
cdk_error_t
cdk_kbnode_hash (cdk_kbnode_t node, digest_hd_st * md, int is_v4,
                 cdk_packet_type_t pkttype, int flags)
{
  cdk_packet_t pkt;

  if (!node || !md)
    {
      gnutls_assert ();
      return CDK_Inv_Value;
    }
  if (!pkttype)
    {
      pkt = cdk_kbnode_get_packet (node);
      pkttype = pkt->pkttype;
    }
  else
    {
      pkt = cdk_kbnode_find_packet (node, pkttype);
      if (!pkt)
        {
          gnutls_assert ();
          return CDK_Inv_Packet;
        }
    }

  switch (pkttype)
    {
    case CDK_PKT_PUBLIC_KEY:
    case CDK_PKT_PUBLIC_SUBKEY:
      _cdk_hash_pubkey (pkt->pkt.public_key, md, flags & 1);
      break;

    case CDK_PKT_USER_ID:
      _cdk_hash_userid (pkt->pkt.user_id, is_v4, md);
      break;

    case CDK_PKT_SIGNATURE:
      _cdk_hash_sig_data (pkt->pkt.signature, md);
      break;

    default:
      gnutls_assert ();
      return CDK_Inv_Mode;
    }
  return 0;
}