xrdp-proprietary/libxrdp/xrdp_sec.c

/*
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

   xrdp: A Remote Desktop Protocol server.
   Copyright (C) Jay Sorg 2004-2008

   secure layer

*/

#include "libxrdp.h"

/* some compilers need unsigned char to avoid warnings */
static tui8 g_pad_54[40] =
{ 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54,
  54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54, 54,
  54, 54, 54, 54, 54, 54, 54, 54 };

/* some compilers need unsigned char to avoid warnings */
static tui8 g_pad_92[48] =
{ 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92,
  92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92,
  92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92, 92 };

/* some compilers need unsigned char to avoid warnings */
static tui8 g_lic1[322] =
{ 0x80, 0x00, 0x3e, 0x01, 0x01, 0x02, 0x3e, 0x01,
  0x7b, 0x3c, 0x31, 0xa6, 0xae, 0xe8, 0x74, 0xf6,
  0xb4, 0xa5, 0x03, 0x90, 0xe7, 0xc2, 0xc7, 0x39,
  0xba, 0x53, 0x1c, 0x30, 0x54, 0x6e, 0x90, 0x05,
  0xd0, 0x05, 0xce, 0x44, 0x18, 0x91, 0x83, 0x81,
  0x00, 0x00, 0x04, 0x00, 0x2c, 0x00, 0x00, 0x00,
  0x4d, 0x00, 0x69, 0x00, 0x63, 0x00, 0x72, 0x00,
  0x6f, 0x00, 0x73, 0x00, 0x6f, 0x00, 0x66, 0x00,
  0x74, 0x00, 0x20, 0x00, 0x43, 0x00, 0x6f, 0x00,
  0x72, 0x00, 0x70, 0x00, 0x6f, 0x00, 0x72, 0x00,
  0x61, 0x00, 0x74, 0x00, 0x69, 0x00, 0x6f, 0x00,
  0x6e, 0x00, 0x00, 0x00, 0x08, 0x00, 0x00, 0x00,
  0x32, 0x00, 0x33, 0x00, 0x36, 0x00, 0x00, 0x00,
  0x0d, 0x00, 0x04, 0x00, 0x01, 0x00, 0x00, 0x00,
  0x03, 0x00, 0xb8, 0x00, 0x01, 0x00, 0x00, 0x00,
  0x01, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00,
  0x06, 0x00, 0x5c, 0x00, 0x52, 0x53, 0x41, 0x31,
  0x48, 0x00, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00,
  0x3f, 0x00, 0x00, 0x00, 0x01, 0x00, 0x01, 0x00,
  0x01, 0xc7, 0xc9, 0xf7, 0x8e, 0x5a, 0x38, 0xe4,
  0x29, 0xc3, 0x00, 0x95, 0x2d, 0xdd, 0x4c, 0x3e,
  0x50, 0x45, 0x0b, 0x0d, 0x9e, 0x2a, 0x5d, 0x18,
  0x63, 0x64, 0xc4, 0x2c, 0xf7, 0x8f, 0x29, 0xd5,
  0x3f, 0xc5, 0x35, 0x22, 0x34, 0xff, 0xad, 0x3a,
  0xe6, 0xe3, 0x95, 0x06, 0xae, 0x55, 0x82, 0xe3,
  0xc8, 0xc7, 0xb4, 0xa8, 0x47, 0xc8, 0x50, 0x71,
  0x74, 0x29, 0x53, 0x89, 0x6d, 0x9c, 0xed, 0x70,
  0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
  0x08, 0x00, 0x48, 0x00, 0xa8, 0xf4, 0x31, 0xb9,
  0xab, 0x4b, 0xe6, 0xb4, 0xf4, 0x39, 0x89, 0xd6,
  0xb1, 0xda, 0xf6, 0x1e, 0xec, 0xb1, 0xf0, 0x54,
  0x3b, 0x5e, 0x3e, 0x6a, 0x71, 0xb4, 0xf7, 0x75,
  0xc8, 0x16, 0x2f, 0x24, 0x00, 0xde, 0xe9, 0x82,
  0x99, 0x5f, 0x33, 0x0b, 0xa9, 0xa6, 0x94, 0xaf,
  0xcb, 0x11, 0xc3, 0xf2, 0xdb, 0x09, 0x42, 0x68,
  0x29, 0x56, 0x58, 0x01, 0x56, 0xdb, 0x59, 0x03,
  0x69, 0xdb, 0x7d, 0x37, 0x00, 0x00, 0x00, 0x00,
  0x00, 0x00, 0x00, 0x00, 0x01, 0x00, 0x00, 0x00,
  0x0e, 0x00, 0x0e, 0x00, 0x6d, 0x69, 0x63, 0x72,
  0x6f, 0x73, 0x6f, 0x66, 0x74, 0x2e, 0x63, 0x6f,
  0x6d, 0x00 };

/* some compilers need unsigned char to avoid warnings */
static tui8 g_lic2[20] =
{ 0x80, 0x00, 0x10, 0x00, 0xff, 0x02, 0x10, 0x00,
  0x07, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x00,
  0x28, 0x14, 0x00, 0x00 };

/* mce */
/* some compilers need unsigned char to avoid warnings */
static tui8 g_lic3[20] =
{ 0x80, 0x02, 0x10, 0x00, 0xff, 0x03, 0x10, 0x00,
  0x07, 0x00, 0x00, 0x00, 0x02, 0x00, 0x00, 0x00,
  0xf3, 0x99, 0x00, 0x00 };

/*****************************************************************************/
static void APP_CC
hex_str_to_bin(char* in, char* out, int out_len)
{
  int in_index;
  int in_len;
  int out_index;
  int val;
  char hex[16];

  in_len = g_strlen(in);
  out_index = 0;
  in_index = 0;
  while (in_index <= (in_len - 4))
  {
    if ((in[in_index] == '0') && (in[in_index + 1] == 'x'))
    {
      hex[0] = in[in_index + 2];
      hex[1] = in[in_index + 3];
      hex[2] = 0;
      if (out_index < out_len)
      {
        val = g_htoi(hex);
        out[out_index] = val;
      }
      out_index++;
    }
    in_index++;
  }
}

/*****************************************************************************/
struct xrdp_sec* APP_CC
xrdp_sec_create(struct xrdp_rdp* owner, int sck, int crypt_level,
                int channel_code)
{
  struct xrdp_sec* self;
  struct list* items;
  struct list* values;
  int index;
  char* item;
  char* value;

  DEBUG((" in xrdp_sec_create"));
  self = (struct xrdp_sec*)g_malloc(sizeof(struct xrdp_sec), 1);
  self->rdp_layer = owner;
  self->rc4_key_size = 1; /* 1 = 40 bit, 2 = 128 bit */
  self->crypt_level = 1; /* 1, 2, 3 = low, medium, high */
  switch (crypt_level)
  {
    case 1:
      self->rc4_key_size = 1;
      self->crypt_level = 1;
      break;
    case 2:
      self->rc4_key_size = 1;
      self->crypt_level = 2;
      break;
    case 3:
      self->rc4_key_size = 2;
      self->crypt_level = 3;
      break;
  }
  self->channel_code = channel_code;
  self->decrypt_rc4_info = ssl_rc4_info_create();
  self->encrypt_rc4_info = ssl_rc4_info_create();
  g_random(self->server_random, 32);
  self->mcs_layer = xrdp_mcs_create(self, sck, &self->client_mcs_data,
                                    &self->server_mcs_data);
  items = list_create();
  items->auto_free = 1;
  values = list_create();
  values->auto_free = 1;
  file_by_name_read_section(XRDP_KEY_FILE, "keys", items, values);
  for (index = 0; index < items->count; index++)
  {
    item = (char*)list_get_item(items, index);
    value = (char*)list_get_item(values, index);
    if (g_strcasecmp(item, "pub_exp") == 0)
    {
      hex_str_to_bin(value, self->pub_exp, 4);
    }
    else if (g_strcasecmp(item, "pub_mod") == 0)
    {
      hex_str_to_bin(value, self->pub_mod, 64);
    }
    else if (g_strcasecmp(item, "pub_sig") == 0)
    {
      hex_str_to_bin(value, self->pub_sig, 64);
    }
    else if (g_strcasecmp(item, "pri_exp") == 0)
    {
      hex_str_to_bin(value, self->pri_exp, 64);
    }
  }
  list_delete(items);
  list_delete(values);
  self->chan_layer = xrdp_channel_create(self, self->mcs_layer);
  DEBUG((" out xrdp_sec_create"));
  return self;
}

/*****************************************************************************/
void APP_CC
xrdp_sec_delete(struct xrdp_sec* self)
{
  if (self == 0)
  {
    return;
  }
  xrdp_channel_delete(self->chan_layer);
  xrdp_mcs_delete(self->mcs_layer);
  ssl_rc4_info_delete(self->decrypt_rc4_info);
  ssl_rc4_info_delete(self->encrypt_rc4_info);
  g_free(self->client_mcs_data.data);
  g_free(self->server_mcs_data.data);
  g_free(self);
}

/*****************************************************************************/
/* returns error */
int APP_CC
xrdp_sec_init(struct xrdp_sec* self, struct stream* s)
{
  if (xrdp_mcs_init(self->mcs_layer, s) != 0)
  {
    return 1;
  }
  if (self->crypt_level > 1)
  {
    s_push_layer(s, sec_hdr, 4 + 8);
  }
  else
  {
    s_push_layer(s, sec_hdr, 4);
  }
  return 0;
}

/*****************************************************************************/
/* Reduce key entropy from 64 to 40 bits */
static void APP_CC
xrdp_sec_make_40bit(char* key)
{
  key[0] = 0xd1;
  key[1] = 0x26;
  key[2] = 0x9e;
}

/*****************************************************************************/
/* returns error */
/* update an encryption key */
static int APP_CC
xrdp_sec_update(char* key, char* update_key, int key_len)
{
  char shasig[20];
  void* sha1_info;
  void* md5_info;
  void* rc4_info;

  sha1_info = ssl_sha1_info_create();
  md5_info = ssl_md5_info_create();
  rc4_info = ssl_rc4_info_create();
  ssl_sha1_clear(sha1_info);
  ssl_sha1_transform(sha1_info, update_key, key_len);
  ssl_sha1_transform(sha1_info, (char*)g_pad_54, 40);
  ssl_sha1_transform(sha1_info, key, key_len);
  ssl_sha1_complete(sha1_info, shasig);
  ssl_md5_clear(md5_info);
  ssl_md5_transform(md5_info, update_key, key_len);
  ssl_md5_transform(md5_info, (char*)g_pad_92, 48);
  ssl_md5_transform(md5_info, shasig, 20);
  ssl_md5_complete(md5_info, key);
  ssl_rc4_set_key(rc4_info, key, key_len);
  ssl_rc4_crypt(rc4_info, key, key_len);
  if (key_len == 8)
  {
    xrdp_sec_make_40bit(key);
  }
  ssl_sha1_info_delete(sha1_info);
  ssl_md5_info_delete(md5_info);
  ssl_rc4_info_delete(rc4_info);
  return 0;
}

/*****************************************************************************/
static void APP_CC
xrdp_sec_decrypt(struct xrdp_sec* self, char* data, int len)
{
  if (self->decrypt_use_count == 4096)
  {
    xrdp_sec_update(self->decrypt_key, self->decrypt_update_key,
                    self->rc4_key_len);
    ssl_rc4_set_key(self->decrypt_rc4_info, self->decrypt_key,
                    self->rc4_key_len);
    self->decrypt_use_count = 0;
  }
  ssl_rc4_crypt(self->decrypt_rc4_info, data, len);
  self->decrypt_use_count++;
}

/*****************************************************************************/
static void APP_CC
xrdp_sec_encrypt(struct xrdp_sec* self, char* data, int len)
{
  if (self->encrypt_use_count == 4096)
  {
    xrdp_sec_update(self->encrypt_key, self->encrypt_update_key,
                    self->rc4_key_len);
    ssl_rc4_set_key(self->encrypt_rc4_info, self->encrypt_key,
                    self->rc4_key_len);
    self->encrypt_use_count = 0;
  }
  ssl_rc4_crypt(self->encrypt_rc4_info, data, len);
  self->encrypt_use_count++;
}

/*****************************************************************************/
static int APP_CC
unicode_in(struct stream* s, int uni_len, char* dst, int dst_len)
{
  int dst_index;
  int src_index;

  dst_index = 0;
  src_index = 0;
  while (src_index < uni_len)
  {
    if (dst_index >= dst_len || src_index > 512)
    {
      break;
    }
    in_uint8(s, dst[dst_index]);
    in_uint8s(s, 1);
    dst_index++;
    src_index += 2;
  }
  in_uint8s(s, 2);
  return 0;
}

/*****************************************************************************/
/* returns error */
static int APP_CC
xrdp_sec_process_logon_info(struct xrdp_sec* self, struct stream* s)
{
  int flags;
  int len_domain;
  int len_user;
  int len_password;
  int len_program;
  int len_directory;
  int len_ip;
  int len_dll;
  int tzone;
  char tmpdata[256];

  in_uint8s(s, 4);
  in_uint32_le(s, flags);
  DEBUG(("in xrdp_sec_process_logon_info flags $%x", flags));
  /* this is the first test that the decrypt is working */
  if ((flags & RDP_LOGON_NORMAL) != RDP_LOGON_NORMAL) /* 0x33 */
  {                                                   /* must be or error */
    return 1;
  }
  if (flags & RDP_LOGON_LEAVE_AUDIO)
  {
    self->rdp_layer->client_info.sound_code = 1;
    DEBUG(("flag RDP_LOGON_LEAVE_AUDIO found"));
  }
  if ((flags & RDP_LOGON_AUTO) && (!self->rdp_layer->client_info.is_mce))
  /* todo, for now not allowing autologon and mce both */
  {
    self->rdp_layer->client_info.rdp_autologin = 1;
    DEBUG(("flag RDP_LOGON_AUTO found"));
  }
  if (flags & RDP_COMPRESSION)
  {
    self->rdp_layer->client_info.rdp_compression = 1;
    DEBUG(("flag RDP_COMPRESSION found"));
  }
  in_uint16_le(s, len_domain);
  in_uint16_le(s, len_user);
  in_uint16_le(s, len_password);
  in_uint16_le(s, len_program);
  in_uint16_le(s, len_directory);
  /* todo, we should error out in any of the above lengths are > 512 */
  /* to avoid buffer overruns */
  unicode_in(s, len_domain, self->rdp_layer->client_info.domain, 255);
  DEBUG(("domain %s", self->rdp_layer->client_info.domain));
  unicode_in(s, len_user, self->rdp_layer->client_info.username, 255);
  DEBUG(("username %s", self->rdp_layer->client_info.username));
  if (flags & RDP_LOGON_AUTO)
  {
    unicode_in(s, len_password, self->rdp_layer->client_info.password, 255);
    DEBUG(("flag RDP_LOGON_AUTO found"));
  }
  else
  {
    in_uint8s(s, len_password + 2);
  }
  unicode_in(s, len_program, self->rdp_layer->client_info.program, 255);
  DEBUG(("program %s", self->rdp_layer->client_info.program));
  unicode_in(s, len_directory, self->rdp_layer->client_info.directory, 255);
  DEBUG(("directory %s", self->rdp_layer->client_info.directory));
  if (flags & RDP_LOGON_BLOB)
  {
    in_uint8s(s, 2);                                    /* unknown */
    in_uint16_le(s, len_ip);
    unicode_in(s, len_ip - 2, tmpdata, 255);
    in_uint16_le(s, len_dll);
    unicode_in(s, len_dll - 2, tmpdata, 255);
    in_uint32_le(s, tzone);                             /* len of timetone */
    in_uint8s(s, 62);                                   /* skip */
    in_uint8s(s, 22);                                   /* skip misc. */
    in_uint8s(s, 62);                                   /* skip */
    in_uint8s(s, 26);                                   /* skip stuff */
    in_uint32_le(s, self->rdp_layer->client_info.rdp5_performanceflags);
  }
  DEBUG(("out xrdp_sec_process_logon_info"));
  return 0;
}

/*****************************************************************************/
/* returns error */
static int APP_CC
xrdp_sec_send_lic_initial(struct xrdp_sec* self)
{
  struct stream* s;

  make_stream(s);
  init_stream(s, 8192);
  if (xrdp_mcs_init(self->mcs_layer, s) != 0)
  {
    free_stream(s);
    return 1;
  }
  out_uint8a(s, g_lic1, 322);
  s_mark_end(s);
  if (xrdp_mcs_send(self->mcs_layer, s, MCS_GLOBAL_CHANNEL) != 0)
  {
    free_stream(s);
    return 1;
  }
  free_stream(s);
  return 0;
}

/*****************************************************************************/
/* returns error */
static int APP_CC
xrdp_sec_send_lic_response(struct xrdp_sec* self)
{
  struct stream* s;

  make_stream(s);
  init_stream(s, 8192);
  if (xrdp_mcs_init(self->mcs_layer, s) != 0)
  {
    free_stream(s);
    return 1;
  }
  out_uint8a(s, g_lic2, 20);
  s_mark_end(s);
  if (xrdp_mcs_send(self->mcs_layer, s, MCS_GLOBAL_CHANNEL) != 0)
  {
    free_stream(s);
    return 1;
  }
  free_stream(s);
  return 0;
}

/*****************************************************************************/
/* returns error */
static int APP_CC
xrdp_sec_send_media_lic_response(struct xrdp_sec* self)
{
  struct stream* s;

  make_stream(s);
  init_stream(s, 8192);
  if (xrdp_mcs_init(self->mcs_layer, s) != 0)
  {
    free_stream(s);
    return 1;
  }
  out_uint8a(s, g_lic3, sizeof(g_lic3));
  s_mark_end(s);
  if (xrdp_mcs_send(self->mcs_layer, s, MCS_GLOBAL_CHANNEL) != 0)
  {
    free_stream(s);
    return 1;
  }
  free_stream(s);
  return 0;
}

/*****************************************************************************/
static void APP_CC
xrdp_sec_rsa_op(char* out, char* in, char* mod, char* exp)
{
  ssl_mod_exp(out, 64, in, 64, mod, 64, exp, 64);
}

/*****************************************************************************/
static void APP_CC
xrdp_sec_hash_48(char* out, char* in, char* salt1, char* salt2, int salt)
{
  int i;
  void* sha1_info;
  void* md5_info;
  char pad[4];
  char sha1_sig[20];
  char md5_sig[16];

  sha1_info = ssl_sha1_info_create();
  md5_info = ssl_md5_info_create();
  for (i = 0; i < 3; i++)
  {
    g_memset(pad, salt + i, 4);
    ssl_sha1_clear(sha1_info);
    ssl_sha1_transform(sha1_info, pad, i + 1);
    ssl_sha1_transform(sha1_info, in, 48);
    ssl_sha1_transform(sha1_info, salt1, 32);
    ssl_sha1_transform(sha1_info, salt2, 32);
    ssl_sha1_complete(sha1_info, sha1_sig);
    ssl_md5_clear(md5_info);
    ssl_md5_transform(md5_info, in, 48);
    ssl_md5_transform(md5_info, sha1_sig, 20);
    ssl_md5_complete(md5_info, md5_sig);
    g_memcpy(out + i * 16, md5_sig, 16);
  }
  ssl_sha1_info_delete(sha1_info);
  ssl_md5_info_delete(md5_info);
}

/*****************************************************************************/
static void APP_CC
xrdp_sec_hash_16(char* out, char* in, char* salt1, char* salt2)
{
  void* md5_info;

  md5_info = ssl_md5_info_create();
  ssl_md5_clear(md5_info);
  ssl_md5_transform(md5_info, in, 16);
  ssl_md5_transform(md5_info, salt1, 32);
  ssl_md5_transform(md5_info, salt2, 32);
  ssl_md5_complete(md5_info, out);
  ssl_md5_info_delete(md5_info);
}

/*****************************************************************************/
static void APP_CC
xrdp_sec_establish_keys(struct xrdp_sec* self)
{
  char session_key[48];
  char temp_hash[48];
  char input[48];

  g_memcpy(input, self->client_random, 24);
  g_memcpy(input + 24, self->server_random, 24);
  xrdp_sec_hash_48(temp_hash, input, self->client_random,
                   self->server_random, 65);
  xrdp_sec_hash_48(session_key, temp_hash, self->client_random,
                   self->server_random, 88);
  g_memcpy(self->sign_key, session_key, 16);
  xrdp_sec_hash_16(self->encrypt_key, session_key + 16, self->client_random,
                   self->server_random);
  xrdp_sec_hash_16(self->decrypt_key, session_key + 32, self->client_random,
                   self->server_random);
  if (self->rc4_key_size == 1)
  {
    xrdp_sec_make_40bit(self->sign_key);
    xrdp_sec_make_40bit(self->encrypt_key);
    xrdp_sec_make_40bit(self->decrypt_key);
    self->rc4_key_len = 8;
  }
  else
  {
    self->rc4_key_len = 16;
  }
  g_memcpy(self->decrypt_update_key, self->decrypt_key, 16);
  g_memcpy(self->encrypt_update_key, self->encrypt_key, 16);
  ssl_rc4_set_key(self->decrypt_rc4_info, self->decrypt_key, self->rc4_key_len);
  ssl_rc4_set_key(self->encrypt_rc4_info, self->encrypt_key, self->rc4_key_len);
}

/*****************************************************************************/
/* returns error */
int APP_CC
xrdp_sec_recv(struct xrdp_sec* self, struct stream* s, int* chan)
{
  int flags;
  int len;

  DEBUG((" in xrdp_sec_recv"));
  if (xrdp_mcs_recv(self->mcs_layer, s, chan) != 0)
  {
    DEBUG((" out xrdp_sec_recv error"));
    return 1;
  }
  in_uint32_le(s, flags);
  DEBUG((" in xrdp_sec_recv flags $%x", flags));
  if (flags & SEC_ENCRYPT) /* 0x08 */
  {
    in_uint8s(s, 8); /* signature */
    xrdp_sec_decrypt(self, s->p, (int)(s->end - s->p));
  }
  if (flags & SEC_CLIENT_RANDOM) /* 0x01 */
  {
    in_uint32_le(s, len);
    in_uint8a(s, self->client_crypt_random, 64);
    xrdp_sec_rsa_op(self->client_random, self->client_crypt_random,
                    self->pub_mod, self->pri_exp);
    xrdp_sec_establish_keys(self);
    *chan = 1; /* just set a non existing channel and exit */
    DEBUG((" out xrdp_sec_recv"));
    return 0;
  }
  if (flags & SEC_LOGON_INFO) /* 0x40 */
  {
    if (xrdp_sec_process_logon_info(self, s) != 0)
    {
      DEBUG((" out xrdp_sec_recv error"));
      return 1;
    }
    if (self->rdp_layer->client_info.is_mce)
    {
      if (xrdp_sec_send_media_lic_response(self) != 0)
      {
        DEBUG((" out xrdp_sec_recv error"));
        return 1;
      }
      DEBUG((" out xrdp_sec_recv"));
      return -1; /* special error that means send demand active */
    }
    if (xrdp_sec_send_lic_initial(self) != 0)
    {
      DEBUG((" out xrdp_sec_recv error"));
      return 1;
    }
    *chan = 1; /* just set a non existing channel and exit */
    DEBUG((" out xrdp_sec_recv"));
    return 0;
  }
  if (flags & SEC_LICENCE_NEG) /* 0x80 */
  {
    if (xrdp_sec_send_lic_response(self) != 0)
    {
      DEBUG((" out xrdp_sec_recv error"));
      return 1;
    }
    DEBUG((" out xrdp_sec_recv"));
    return -1; /* special error that means send demand active */
  }
  DEBUG((" out xrdp_sec_recv"));
  return 0;
}

/*****************************************************************************/
/* Output a uint32 into a buffer (little-endian) */
static void
buf_out_uint32(char* buffer, int value)
{
  buffer[0] = (value) & 0xff;
  buffer[1] = (value >> 8) & 0xff;
  buffer[2] = (value >> 16) & 0xff;
  buffer[3] = (value >> 24) & 0xff;
}

/*****************************************************************************/
/* Generate a MAC hash (5.2.3.1), using a combination of SHA1 and MD5 */
static void APP_CC
xrdp_sec_sign(struct xrdp_sec* self, char* out, int out_len,
              char* data, int data_len)
{
  char shasig[20];
  char md5sig[16];
  char lenhdr[4];
  void* sha1_info;
  void* md5_info;

  buf_out_uint32(lenhdr, data_len);
  sha1_info = ssl_sha1_info_create();
  md5_info = ssl_md5_info_create();
  ssl_sha1_clear(sha1_info);
  ssl_sha1_transform(sha1_info, self->sign_key, self->rc4_key_len);
  ssl_sha1_transform(sha1_info, (char*)g_pad_54, 40);
  ssl_sha1_transform(sha1_info, lenhdr, 4);
  ssl_sha1_transform(sha1_info, data, data_len);
  ssl_sha1_complete(sha1_info, shasig);
  ssl_md5_clear(md5_info);
  ssl_md5_transform(md5_info, self->sign_key, self->rc4_key_len);
  ssl_md5_transform(md5_info, (char*)g_pad_92, 48);
  ssl_md5_transform(md5_info, shasig, 20);
  ssl_md5_complete(md5_info, md5sig);
  g_memcpy(out, md5sig, out_len);
  ssl_sha1_info_delete(sha1_info);
  ssl_md5_info_delete(md5_info);
}

/*****************************************************************************/
/* returns error */
int APP_CC
xrdp_sec_send(struct xrdp_sec* self, struct stream* s, int chan)
{
  int datalen;

  DEBUG((" in xrdp_sec_send"));
  s_pop_layer(s, sec_hdr);
  if (self->crypt_level > 1)
  {
    out_uint32_le(s, SEC_ENCRYPT);
    datalen = (int)((s->end - s->p) - 8);
    xrdp_sec_sign(self, s->p, 8, s->p + 8, datalen);
    xrdp_sec_encrypt(self, s->p + 8, datalen);
  }
  else
  {
    out_uint32_le(s, 0);
  }
  if (xrdp_mcs_send(self->mcs_layer, s, chan) != 0)
  {
    return 1;
  }
  DEBUG((" out xrdp_sec_send"));
  return 0;
}

/*****************************************************************************/
/* this adds the mcs channels in the list of channels to be used when
   creating the server mcs data */
static int APP_CC
xrdp_sec_process_mcs_data_channels(struct xrdp_sec* self, struct stream* s)
{
  int num_channels;
  int index;
  struct mcs_channel_item* channel_item;

  DEBUG(("processing channels, channel_code is %d", self->channel_code));
  /* this is an option set in xrdp.ini */
  if (self->channel_code != 1) /* are channels on? */
  {
    return 0;
  }
  in_uint32_le(s, num_channels);
  for (index = 0; index < num_channels; index++)
  {
    channel_item = (struct mcs_channel_item*)
             g_malloc(sizeof(struct mcs_channel_item), 1);
    in_uint8a(s, channel_item->name, 8);
    in_uint32_be(s, channel_item->flags);
    channel_item->chanid = MCS_GLOBAL_CHANNEL + (index + 1);
    list_add_item(self->mcs_layer->channel_list, (long)channel_item);
    DEBUG(("got channel flags %8.8x name %s", channel_item->flags,
           channel_item->name));
  }
  return 0;
}

/*****************************************************************************/
/* process client mcs data, we need some things in here to create the server
   mcs data */
int APP_CC
xrdp_sec_process_mcs_data(struct xrdp_sec* self)
{
  struct stream* s;
  char* hold_p;
  int tag;
  int size;

  s = &self->client_mcs_data;
  /* set p to beginning */
  s->p = s->data;
  /* skip header */
  in_uint8s(s, 23);
  while (s_check_rem(s, 4))
  {
    hold_p = s->p;
    in_uint16_le(s, tag);
    in_uint16_le(s, size);
    if (size < 4 || !s_check_rem(s, size - 4))
    {
      g_writeln("error in xrdp_sec_process_mcs_data tag %d size %d",
                tag, size);
      break;
    }
    switch (tag)
    {
      case SEC_TAG_CLI_INFO:
        break;
      case SEC_TAG_CLI_CRYPT:
        break;
      case SEC_TAG_CLI_CHANNELS:
        xrdp_sec_process_mcs_data_channels(self, s);
        break;
      case SEC_TAG_CLI_4:
        break;
      default:
        g_writeln("error unknown xrdp_sec_process_mcs_data tag %d size %d",
                  tag, size);
        break;
    }
    s->p = hold_p + size;
  }
  /* set p to beginning */
  s->p = s->data;
  return 0;
}

/*****************************************************************************/
/* prepare server mcs data to send in mcs layer */
int APP_CC
xrdp_sec_out_mcs_data(struct xrdp_sec* self)
{
  struct stream* s;
  int num_channels_even;
  int num_channels;
  int index;
  int channel;

  num_channels = self->mcs_layer->channel_list->count;
  num_channels_even = num_channels + (num_channels & 1);
  s = &self->server_mcs_data;
  init_stream(s, 512);
  out_uint16_be(s, 5);
  out_uint16_be(s, 0x14);
  out_uint8(s, 0x7c);
  out_uint16_be(s, 1);
  out_uint8(s, 0x2a);
  out_uint8(s, 0x14);
  out_uint8(s, 0x76);
  out_uint8(s, 0x0a);
  out_uint8(s, 1);
  out_uint8(s, 1);
  out_uint8(s, 0);
  out_uint16_le(s, 0xc001);
  out_uint8(s, 0);
  out_uint8(s, 0x4d); /* M */
  out_uint8(s, 0x63); /* c */
  out_uint8(s, 0x44); /* D */
  out_uint8(s, 0x6e); /* n */
  out_uint16_be(s, 0x80fc + (num_channels_even * 2));
  out_uint16_le(s, SEC_TAG_SRV_INFO);
  out_uint16_le(s, 8); /* len */
  out_uint8(s, 4); /* 4 = rdp5 1 = rdp4 */
  out_uint8(s, 0);
  out_uint8(s, 8);
  out_uint8(s, 0);
  out_uint16_le(s, SEC_TAG_SRV_CHANNELS);
  out_uint16_le(s, 8 + (num_channels_even * 2)); /* len */
  out_uint16_le(s, MCS_GLOBAL_CHANNEL); /* 1003, 0x03eb main channel */
  out_uint16_le(s, num_channels); /* number of other channels */
  for (index = 0; index < num_channels_even; index++)
  {
    if (index < num_channels)
    {
      channel = MCS_GLOBAL_CHANNEL + (index + 1);
      out_uint16_le(s, channel);
    }
    else
    {
      out_uint16_le(s, 0);
    }
  }
  out_uint16_le(s, SEC_TAG_SRV_CRYPT);
  out_uint16_le(s, 0x00ec); /* len is 236 */
  out_uint32_le(s, self->rc4_key_size); /* key len 1 = 40 bit 2 = 128 bit */
  out_uint32_le(s, self->crypt_level); /* crypt level 1 = low 2 = medium */
                                       /* 3 = high */
  out_uint32_le(s, 32);     /* 32 bytes random len */
  out_uint32_le(s, 0xb8);   /* 184 bytes rsa info(certificate) len */
  out_uint8a(s, self->server_random, 32);
  /* here to end is certificate */
  /* HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\ */
  /* TermService\Parameters\Certificate */
  out_uint32_le(s, 1);
  out_uint32_le(s, 1);
  out_uint32_le(s, 1);
  out_uint16_le(s, SEC_TAG_PUBKEY);
  out_uint16_le(s, 0x005c); /* 92 bytes length of SEC_TAG_PUBKEY */
  out_uint32_le(s, SEC_RSA_MAGIC);
  out_uint32_le(s, 0x48); /* 72 bytes modulus len */
  out_uint32_be(s, 0x00020000);
  out_uint32_be(s, 0x3f000000);
  out_uint8a(s, self->pub_exp, 4); /* pub exp */
  out_uint8a(s, self->pub_mod, 64); /* pub mod */
  out_uint8s(s, 8); /* pad */
  out_uint16_le(s, SEC_TAG_KEYSIG);
  out_uint16_le(s, 72); /* len */
  out_uint8a(s, self->pub_sig, 64); /* pub sig */
  out_uint8s(s, 8); /* pad */
  /* end certificate */
  s_mark_end(s);
  return 0;
}

/*****************************************************************************/
/* process the mcs client data we received from the mcs layer */
static void APP_CC
xrdp_sec_in_mcs_data(struct xrdp_sec* self)
{
  struct stream* s;
  struct xrdp_client_info* client_info;
  int index;
  char c;

  client_info = &self->rdp_layer->client_info;
  s = &self->client_mcs_data;
  /* get hostname, its unicode */
  s->p = s->data;
  in_uint8s(s, 47);
  g_memset(client_info->hostname, 0, 32);
  c = 1;
  index = 0;
  while (index < 16 && c != 0)
  {
    in_uint8(s, c);
    in_uint8s(s, 1);
    client_info->hostname[index] = c;
    index++;
  }
  /* get build */
  s->p = s->data;
  in_uint8s(s, 43);
  in_uint32_le(s, client_info->build);
  /* get keylayout */
  s->p = s->data;
  in_uint8s(s, 39);
  in_uint32_le(s, client_info->keylayout);
  s->p = s->data;
}

/*****************************************************************************/
int APP_CC
xrdp_sec_incoming(struct xrdp_sec* self)
{
  DEBUG((" in xrdp_sec_incoming"));
  if (xrdp_mcs_incoming(self->mcs_layer) != 0)
  {
    return 1;
  }
#ifdef XRDP_DEBUG
  g_writeln("client mcs data received");
  g_hexdump(self->client_mcs_data.data,
            (int)(self->client_mcs_data.end - self->client_mcs_data.data));
  g_writeln("server mcs data sent");
  g_hexdump(self->server_mcs_data.data,
            (int)(self->server_mcs_data.end - self->server_mcs_data.data));
#endif
  DEBUG((" out xrdp_sec_incoming"));
  xrdp_sec_in_mcs_data(self);
  return 0;
}

/*****************************************************************************/
int APP_CC
xrdp_sec_disconnect(struct xrdp_sec* self)
{
  int rv;

  DEBUG((" in xrdp_sec_disconnect"));
  rv = xrdp_mcs_disconnect(self->mcs_layer);
  DEBUG((" out xrdp_sec_disconnect"));
  return rv;
}