/*
   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 2005-2008
*/

/**
 *
 * @file verify_user.c
 * @brief Authenticate user using standard unix passwd/shadow system
 * @author Jay Sorg, Simone Fedele
 *
 */

#include "sesman.h"

#define _XOPEN_SOURCE
#include <stdio.h>
#include <sys/types.h>
#include <crypt.h>
#include <shadow.h>
#include <pwd.h>

#ifndef SECS_PER_DAY
#define SECS_PER_DAY (24L*3600L)
#endif

extern struct config_sesman* g_cfg; /* in sesman.c */

static int DEFAULT_CC
auth_crypt_pwd(char* pwd, char* pln, char* crp);

static int DEFAULT_CC
auth_account_disabled(struct spwd* stp);

/******************************************************************************/
/* returns boolean */
long DEFAULT_CC
auth_userpass(char* user, char* pass)
{
  char salt[13] = "$1$";
  char hash[35] = "";
  char* encr = 0;
  struct passwd* spw;
  struct spwd* stp;
  int saltcnt = 0;

  spw = getpwnam(user);
  if (spw == 0)
  {
    return 0;
  }
  if (g_strncmp(spw->pw_passwd, "x", 3) == 0)
  {
    /* the system is using shadow */
    stp = getspnam(user);
    if (stp == 0)
    {
      return 0;
    }
    if (1==auth_account_disabled(stp))
    {
      log_message(&(g_cfg->log), LOG_LEVEL_INFO, "account %s is disabled", user);
      return 0;
    }
    g_strncpy(hash, stp->sp_pwdp, 34);
  }
  else
  {
    /* old system with only passwd */
    g_strncpy(hash, spw->pw_passwd, 34);
  }
  hash[34] = '\0';
  if (g_strncmp(hash, "$1$", 3) == 0)
  {
    /* gnu style crypt(); */
    saltcnt = 3;
    while ((hash[saltcnt] != '$') && (saltcnt < 11))
    {
      salt[saltcnt] = hash[saltcnt];
      saltcnt++;
    }
    salt[saltcnt] = '$';
    salt[saltcnt + 1] = '\0';
  }
  else
  {
    /* classic two char salt */
    salt[0] = hash[0];
    salt[1] = hash[1];
    salt[2] = '\0';
  }
  encr = crypt(pass,salt);
  if (g_strncmp(encr, hash, 34) != 0)
  {
    return 0;
  }
  return 1;
}

/******************************************************************************/
/* returns error */
int DEFAULT_CC
auth_start_session(long in_val, int in_display)
{
  return 0;
}

/******************************************************************************/
int DEFAULT_CC
auth_end(long in_val)
{
  return 0;
}

/******************************************************************************/
int DEFAULT_CC
auth_set_env(long in_val)
{
  return 0;
}

/******************************************************************************/
int DEFAULT_CC
auth_check_pwd_chg(char* user)
{
  struct passwd* spw;
  struct spwd* stp;
  int now;
  long today;

  spw = getpwnam(user);
  if (spw == 0)
  {
    return AUTH_PWD_CHG_ERROR;
  }
  if (g_strncmp(spw->pw_passwd, "x", 3) != 0)
  {
    /* old system with only passwd */
    return AUTH_PWD_CHG_OK;
  }

  /* the system is using shadow */
  stp = getspnam(user);
  if (stp == 0)
  {
    return AUTH_PWD_CHG_ERROR;
  }

  /* check if we need a pwd change */
  now=g_time1();
  today=now/SECS_PER_DAY;

  if (stp->sp_expire == -1)
  {
    return AUTH_PWD_CHG_OK;
  }
  if (today >= (stp->sp_lstchg + stp->sp_max - stp->sp_warn))
  {
    return AUTH_PWD_CHG_CHANGE;
  }

  if (today >= (stp->sp_lstchg + stp->sp_max))
  {
    return AUTH_PWD_CHG_CHANGE_MANDATORY;
  }

  if (today < ((stp->sp_lstchg)+(stp->sp_min)))
  {
    /* cannot change pwd for now */
    return AUTH_PWD_CHG_NOT_NOW;
  }

  return AUTH_PWD_CHG_OK;
}

int DEFAULT_CC
auth_change_pwd(char* user, char* newpwd)
{
  struct passwd* spw;
  struct spwd* stp;
  char hash[35] = "";
  long today;

  FILE* fd;

  if (0 != lckpwdf())
  {
    return 1;
  }

  /* open passwd */
  spw = getpwnam(user);
  if (spw == 0)
  {
    return 1;
  }

  if (g_strncmp(spw->pw_passwd, "x", 3) != 0)
  {
    /* old system with only passwd */
    if (auth_crypt_pwd(spw->pw_passwd, newpwd, hash) != 0)
    {
      ulckpwdf();
      return 1;
    }

    spw->pw_passwd=g_strdup(hash);
    fd = fopen("/etc/passwd", "rw");
    putpwent(spw, fd);
  }
  else
  {
    /* the system is using shadow */
    stp = getspnam(user);
    if (stp == 0)
    {
      return 1;
    }

    /* old system with only passwd */
    if (auth_crypt_pwd(stp->sp_pwdp, newpwd, hash) != 0)
    {
      ulckpwdf();
      return 1;
    }

    stp->sp_pwdp = g_strdup(hash);
    today = g_time1() / SECS_PER_DAY;
    stp->sp_lstchg = today;
    stp->sp_expire = today + stp->sp_max + stp->sp_inact;
    fd = fopen("/etc/shadow", "rw");
    putspent(stp, fd);
  }

  ulckpwdf();
  return 0;
}

/**
 *
 * @brief Password encryption
 * @param pwd Old password
 * @param pln Plaintext new password
 * @param crp Crypted new password
 *
 */

static int DEFAULT_CC
auth_crypt_pwd(char* pwd, char* pln, char* crp)
{
  char salt[13] = "$1$";
  int saltcnt = 0;
  char* encr;

  if (g_strncmp(pwd, "$1$", 3) == 0)
  {
    /* gnu style crypt(); */
    saltcnt = 3;
    while ((pwd[saltcnt] != '$') && (saltcnt < 11))
    {
      salt[saltcnt] = pwd[saltcnt];
      saltcnt++;
    }
    salt[saltcnt] = '$';
    salt[saltcnt + 1] = '\0';
  }
  else
  {
    /* classic two char salt */
    salt[0] = pwd[0];
    salt[1] = pwd[1];
    salt[2] = '\0';
  }

  encr = crypt(pln, salt);
  g_strncpy(crp, encr, 34);

  return 0;
}

/**
 *
 * @return 1 if the account is disabled, 0 otherwise
 *
 */
static int DEFAULT_CC
auth_account_disabled(struct spwd* stp)
{
  int today;

  if (0==stp)
  {
    /* if an invalid struct was passed we assume a disabled account */
    return 1;
  }

  today=g_time1()/SECS_PER_DAY;

  LOG_DBG(&(g_cfg->log), "last   %d",stp->sp_lstchg);
  LOG_DBG(&(g_cfg->log), "min    %d",stp->sp_min);
  LOG_DBG(&(g_cfg->log), "max    %d",stp->sp_max);
  LOG_DBG(&(g_cfg->log), "inact  %d",stp->sp_inact);
  LOG_DBG(&(g_cfg->log), "warn   %d",stp->sp_warn);
  LOG_DBG(&(g_cfg->log), "expire %d",stp->sp_expire);
  LOG_DBG(&(g_cfg->log), "today  %d",today);

  if ((stp->sp_expire != -1) && (today >= stp->sp_expire))
  {
    return 1;
  }

  if (today >= (stp->sp_lstchg+stp->sp_max+stp->sp_inact))
  {
    return 1;
  }

  return 0;
}