<?php

# Copyright (c) 2010-2016 Yubico AB
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are
# met:
#
#   * Redistributions of source code must retain the above copyright
#     notice, this list of conditions and the following disclaimer.
#
#   * Redistributions in binary form must reproduce the above
#     copyright notice, this list of conditions and the following
#     disclaimer in the documentation and/or other materials provided
#     with the distribution.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

require_once 'ykval-common.php';

class LogVerify
{
    public $format = NULL;

    private $fields = array(
        'time_start' => NULL,
        'time_end' => NULL,
        'time_taken' => NULL,
        'ip' => NULL,
        'client' => NULL,
        'public_id' => NULL,
        'otp' => NULL,
        'status' => NULL,
        'nonce' => NULL,
        'signed' => NULL,
        'counter' => NULL,
        'low' => NULL,
        'high' => NULL,
        'use' => NULL,
        'tls' => NULL,
        'protocol' => NULL,
        'sl' => NULL,
        'timeout' => NULL,
    );

    /**
     * Set field value.
     *
     * @param $name string
     * @param $value mixed
     * @return bool
     */
    public function set($name, $value)
    {
        // not settable from outside
        if ($name === 'time_end' || $name === 'time_taken')
            return false;

        if (array_key_exists($name, $this->fields) === FALSE)
            return false;

        $this->fields[$name] = $value;
        return true;
    }

    /**
     * Write verify request log line to syslog.
     *
     * @return bool
     */
    public function write()
    {
        if ($this->format === NULL)
            return false;

        $values = array();
        foreach ($this->sanitized() as $key => $val)
        {
            $values['%'.$key.'%'] = $val;
        }

        $message = strtr($this->format, $values);

        if (!is_string($message))
            return false;

        return syslog(LOG_INFO, $message);
    }

    /**
     * Sanitize untrusted values from clients before writing them to syslog.
     *
     * P.S. signed, status, time_start, tls are assumed safe,
     *	since they are set internally.
     *
     * @return array sanitized $this->fields
     */
    private function sanitized()
    {
        $a = $this->fields;

        if (preg_match('/^[cbdefghijklnrtuv]+$/', $a['public_id']) !== 1
            || strlen($a['public_id']) < 1
            || strlen($a['public_id']) > (OTP_MAX_LEN - TOKEN_LEN))
        {
            $a['public_id'] = '-';
        }

        if (preg_match('/^[cbdefghijklnrtuv]+$/', $a['otp']) !== 1
            || strlen($a['otp']) < TOKEN_LEN
            || strlen($a['otp']) > OTP_MAX_LEN)
        {
            $a['otp'] = '-';
        }

        if (preg_match('/^[0-9]+$/', $a['client']) !== 1)
            $a['client'] = '-';

        if (filter_var($a['ip'], FILTER_VALIDATE_IP) === FALSE)
            $a['ip'] = '-';

        if (is_int($a['counter']) === FALSE)
            $a['counter'] = '-';

        if (is_int($a['low']) === FALSE)
            $a['low'] = '-';

        if (is_int($a['high']) === FALSE)
            $a['high'] = '-';

        if (is_int($a['use']) === FALSE)
            $a['use'] = '-';

        if (preg_match('/^[a-zA-Z0-9]{16,40}$/', $a['nonce']) !== 1)
            $a['nonce'] = '-';

        if (is_float($a['protocol']) === TRUE)
            $a['protocol'] = sprintf('%.1f', $a['protocol']);
        else
            $a['protocol'] = '-';

        if (   $a['sl'] !== 'fast'
               && $a['sl'] !== 'secure'
               && (preg_match('/^[0-9]{1,3}$/', $a['sl']) !== 1 || (((int) $a['sl']) > 100)))
        {
            $a['sl'] = '-';
        }

        if (preg_match('/^[0-9]+$/', $a['timeout']) !== 1)
            $a['timeout'] = '-';

        $start = explode(' ', $a['time_start']);
        $start_msec = $start[0];
        $start_sec = $start[1];
        $start = bcadd($start_sec, $start_msec, 8);
        unset($start_sec, $start_msec);

        $end = explode(' ', microtime());
        $end_msec = $end[0];
        $end_sec = $end[1];
        $end = bcadd($end_sec, $end_msec, 8);
        unset($end_sec, $end_msec);

        $taken = bcsub($end, $start, 8);

        $a['time_start'] = $start;
        $a['time_end'] = $end;
        $a['time_taken'] = $taken;

        return $a;
    }
}