#!/usr/bin/perl
#
# Warden.pm
#
# Copyright (C) 2011-2013 Cesnet z.s.p.o
#
# Use of this source is governed by a BSD-style license, see LICENSE file.

package Warden;

use strict;
use warnings;

use DBI;
use DBD::mysql;
use Sys::Syslog qw(:DEFAULT setlogsock);
Sys::Syslog::setlogsock('unix');
use Net::CIDR::Lite;
use DateTime;
use MIME::Base64;
use Crypt::X509;
use SOAP::Lite;
use Carp;
use File::Basename;

my $basedir = "/opt/warden-server/";
use lib $basedir . "lib";
use WardenCommon;



################################################################################
#				VARIABLES
################################################################################
our $VERSION = "2.2";
my $etc = $basedir . "etc";
our $FILENAME = File::Basename::basename($0);



################################################################################
#			READING OF CONFIGURATION VARIABLES
################################################################################
my $conf_file = "$etc/warden-server.conf";
WardenCommon::loadConf($conf_file);



################################################################################
#				DB CONNECT
################################################################################
our $DBH = DBI->connect("DBI:mysql:database=$WardenCommon::DB_NAME;host=$WardenCommon::DB_HOST", $WardenCommon::DB_USER, $WardenCommon::DB_PASS, {RaiseError => 1, mysql_auto_reconnect => 1})
           || die "Could not connect to database: $DBI::errstr";



################################################################################
#				FUNCTIONS
################################################################################

#-------------------------------------------------------------------------------
# sendMsg - wrapper for more complex WardenCommon::sendMsg function
#-------------------------------------------------------------------------------
sub sendMsg
{
  my $severity          = shift;
  my $syslog_msg        = shift;
  my $soap_msg          = shift;

  WardenCommon::sendMsg($WardenCommon::SYSLOG, $WardenCommon::SYSLOG_VERBOSE, $WardenCommon::SYSLOG_FACILITY, $severity,
			$syslog_msg, $soap_msg, $FILENAME);
}


#-------------------------------------------------------------------------------
# getAltNames - parse Alternate names from SSL certifiate
#-------------------------------------------------------------------------------
sub getAltNames
{
  my @an_array;
  my $cn = $ENV{'SSL_CLIENT_S_DN_CN'};

  push(@an_array, $DBH->quote($cn));
  my @a = split("\n", $ENV{'SSL_CLIENT_CERT'});
  pop @a;
  shift @a;
  my $der = decode_base64(join("", @a));
  my $decoded= Crypt::X509->new(cert => $der);

  foreach my $tmp (@{$decoded->SubjectAltName}) {
    if($tmp =~ s/dNSName=//){
      push(@an_array, $DBH->quote($tmp));
    }
  }
  my $alt_names = join(',', @an_array);
  return $alt_names;
}


#-------------------------------------------------------------------------------
# authorizeClient - authorize client by CN,AN and source IP range
#-------------------------------------------------------------------------------

sub authorizeClient
{
  my ($alt_names, $ip, $service_type, $client_type, $function_name) = @_;
  my $sth;

  # obtain cidr based on rigth common name and alternate names, service and client_type
  if($function_name eq 'saveNewEvent') {
    $sth = $DBH->prepare("SELECT client_id, ip_net_client, receive_own_events FROM clients WHERE hostname IN ($alt_names) AND service = ? AND client_type = ? ORDER BY SUBSTRING_INDEX(ip_net_client,'/', -1) DESC;");
  } elsif($function_name eq 'getNewEvents') {
    $sth = $DBH->prepare("SELECT client_id, ip_net_client, receive_own_events FROM clients WHERE hostname IN ($alt_names) AND (type = ? OR type = '_any_') AND client_type = ? ORDER BY SUBSTRING_INDEX(ip_net_client,'/', -1) DESC;");
  } elsif($function_name eq 'getClientInfo') {
    $sth = $DBH->prepare("SELECT client_id, ip_net_client, receive_own_events FROM clients WHERE hostname IN ($alt_names) ORDER BY SUBSTRING_INDEX(ip_net_client,'/', -1) DESC;");
  } elsif($function_name eq 'getLastId') {
    $sth = $DBH->prepare("SELECT client_id, ip_net_client, receive_own_events FROM clients WHERE hostname IN ($alt_names) AND client_type = 'r' ORDER BY SUBSTRING_INDEX(ip_net_client,'/', -1) DESC;");
 }

  # check db handler
  if (!defined $sth) {
    sendMsg("err",
            "Cannot prepare authorization statement in $function_name: $DBH->errstr",
	    "Internal 'prepare' server error");
  }

  # execute query for two or none params functions
  if ($function_name eq 'saveNewEvent' || $function_name eq 'getNewEvents') {
    $sth->execute($service_type, $client_type);
  } else {
    $sth->execute;
  }

  # obtain registration info about clients
  my ($client_id, $ip_net_client, $receive_own, $ip_net_client_list);
  my $correct_ip_source = 0;
  my %ret;
  while(($client_id, $ip_net_client, $receive_own)  = $sth->fetchrow()) {
    my $ip_net_client_list = Net::CIDR::Lite->new->add($ip_net_client);

    $ret{'client_id'}	= $client_id;
    $ret{'receive_own'} = $receive_own;

    if ($ip_net_client_list->bin_find($ip)) {
      $correct_ip_source = 1;
      last;
    }
  }

  # check if client is registered
  if ($sth->rows == 0) {
    sendMsg("err",
            "Unauthorized access to function '$function_name' from [IP: '$ip'; CN(AN): $alt_names; Client_type: '$client_type'; Service/Type: '$service_type'] - client is not registered at Warden server '$ENV{'SERVER_NAME'}'",
            "Access denied - client is not registered at Warden server '$ENV{'SERVER_NAME'}'");
    return undef;
  }

  # check if client has IP from registered CIDR
  if (!$correct_ip_source) {
    sendMsg ("err",
             "Unauthorized access to function '$function_name' from [IP: '$ip'; CN(AN): $alt_names; Client_type: '$client_type'; Service/Type: '$service_type'] - access to Warden server '$ENV{'SERVER_NAME'}' from another subnet than '$ip_net_client'",
             "Access denied - access to Warden server '$ENV{'SERVER_NAME'}' from unauthorized subnet '$ip_net_client'");
    return undef;
  }

  return %ret;
} # END of authorizeClient



################################################################################
# 				SOAP Functions
################################################################################

#-----------------------------------------------------------------------------
# saveNewEvent - save new received event into database
#-----------------------------------------------------------------------------
sub saveNewEvent
{
  my ($class, $data) = @_;
  my $sth;

  # client network information
  my $cn	= $ENV{'SSL_CLIENT_S_DN_CN'};
  my $alt_names = getAltNames(undef);
  my $ip	= $ENV{'REMOTE_ADDR'};

  # variables defined by server
  my $function_name	= 'saveNewEvent';
  my $client_type	= 's';			# incoming client MUST be sender
  my $valid		= 't';			# registered sender has valid events
  my $received		= DateTime->now;	# time of event delivery (UTC)

  # parse object (event) parameters
  my $service		= $data->{'SERVICE'};
  my $detected		= $data->{'DETECTED'};
  my $type		= $data->{'TYPE'};
  my $source_type	= $data->{'SOURCE_TYPE'};
  my $source		= $data->{'SOURCE'};
  my $target_proto	= $data->{'TARGET_PROTO'};
  my $target_port	= $data->{'TARGET_PORT'};
  my $attack_scale 	= $data->{'ATTACK_SCALE'};
  my $note		= $data->{'NOTE'};
  my $priority		= $data->{'PRIORITY'};
  my $timeout		= $data->{'TIMEOUT'};

  my %client = authorizeClient($alt_names, $ip, $service, $client_type, $function_name);
  if (defined %client) {
    sendMsg("debug",
            "Incoming event: [service: '$service', detected: '$detected', type: '$type', source_type: '$source_type', source: '$source', target_proto: '$target_proto', target_port: '$target_port', attack_scale: '$attack_scale', note: '$note', priority: '$priority', timeout: '$timeout']",
             undef);
    if (%WardenCommon::VALID_STRINGS) {	# check if hash is not empty - use VALIDATION HASH
      if (!(exists $WardenCommon::VALID_STRINGS{'type'} && grep $type eq $_, @{$WardenCommon::VALID_STRINGS{'type'}})) {
        sendMsg("err",
                "Unknown event type from [IP: '$ip'; CN(AN): $alt_names; Service: '$service'; Type: '$type']",
	        "Unknown event type: '$type'");
      } elsif (!(exists $WardenCommon::VALID_STRINGS{'source_type'} && grep $source_type eq $_, @{$WardenCommon::VALID_STRINGS{'source_type'}})) {
        sendMsg("err",
                "Unknown source type from [IP '$ip'; CN(AN): $alt_names; Service: '$service'; Source_type: '$source_type']",
                "Unknown source type: '$source_type'");
      }
    }

    # http://my.safaribooksonline.com/book/programming/regular-expressions/9780596802837/4dot-validation-and-formatting/id2983571
    if ($detected !~ /^((?:[1-9][0-9]*)?[0-9]{4})-(1[0-2]|0[1-9])-(3[0-1]|0[1-9]|[1-2][0-9])T(2[0-3]|[0-1][0-9]):([0-5][0-9]):([0-5][0-9])(\.[0-9]+)?(Z|[+-](?:2[0-3]|[0-1][0-9]):[0-5][0-9])?/) {
      sendMsg("err",
              "Unknown detected time format from [IP: '$ip'; CN(AN): $alt_names; Service: '$service'; Detected: '$detected']",
              "Unknown detected time format: '$detected'");
    }

    my @change_list;
    if (defined $target_port && $target_port !~ /^\d+\z/) {
      push(@change_list, "target_port: '$target_port'");
      $target_port = undef;
    }
    if (defined $attack_scale && $attack_scale !~ /^\d+\z/) {
      push(@change_list, "attack_scale: '$attack_scale'");
      $attack_scale = undef;
    }
    if (defined $priority && $priority !~ /^\d+\z/) {
      push(@change_list, "priority: '$priority'");
      $priority = undef;
    }
    if (defined $timeout && $timeout !~ /^\d+\z/) {
      push(@change_list, "timeout: '$timeout'");
      $timeout = undef;
    }
    my $change_string = join(", ", @change_list);
    if ($change_string ne "") {
      sendMsg("info",
              "Unknown event items detected {originaly - $change_string} received in $received from [IP '$ip'; CN(AN): $alt_names; Service: '$service'; Type: '$type'; Detected: $detected]",
              undef);
    }

    $sth=$DBH->prepare("INSERT INTO events VALUES (?,?,?,?,?,?,?,?,?,?,?,?,?,?);");
    if (!defined $sth) {
      sendMsg("err",
              "Cannot prepare statement in function '$function_name': $DBH->errstr",
	      "Internal 'prepare' server error");
    }
    $sth->execute(undef, $detected, $received, $type, $source_type, $source, $target_proto, $target_port, $attack_scale, $note, $priority, $timeout, $valid, $client{'client_id'});
    return 1;
  }
} # END of saveNewEvent


#-----------------------------------------------------------------------------
# getNewEvents - get new events from the DB greater than received ID
#-----------------------------------------------------------------------------
sub getNewEvents
{
  my ($class, $data) = @_;
  my ($sth, @events, $event, @ids);
  my ($id, $hostname, $service, $detected, $type, $source_type, $source, $target_proto, $target_port, $attack_scale, $note, $priority, $timeout, $client_id);

  # client network information
  my $cn	= $ENV{'SSL_CLIENT_S_DN_CN'};
  my $alt_names	= getAltNames(undef);
  my $ip	= $ENV{'REMOTE_ADDR'};

  my $client_type	= 'r';	# incoming client MUST be sender
  my $function_name	= 'getNewEvents';

  # parse SOAP data object
  my $requested_type		= $data->{'REQUESTED_TYPE'} || '_any_';
  my $last_id			= $data->{'LAST_ID'};
  my $max_rcv_events_limit 	= $data->{'MAX_RCV_EVENTS_LIMIT'}; # client events limit

  # comparison of client and server limit - which can be used
  my $used_limit;
  if (defined $max_rcv_events_limit && $max_rcv_events_limit < $WardenCommon::MAX_EVENTS_LIMIT) {
    $used_limit = $max_rcv_events_limit;
  } else {
    $used_limit = $WardenCommon::MAX_EVENTS_LIMIT;
  }

  my %client = authorizeClient($alt_names, $ip, $requested_type, $client_type, $function_name);
  if(defined %client) {
    if ($client{'receive_own'} eq 't') {
      if ($requested_type eq '_any_') {
        $sth = $DBH->prepare("SELECT * FROM events WHERE type != 'test' AND id > ? AND valid = 't' ORDER BY id ASC LIMIT ?;");
        if (!defined $sth) {
	  sendMsg("err",
	         "Cannot prepare ROE-ANY statement in function '$function_name': $DBH->errstr",
		 "Internal 'prepare' server error");
        }
        $sth->execute($last_id, $used_limit);
      } else {
        $sth = $DBH->prepare("SELECT * FROM events WHERE type != 'test' AND id > ? AND type = ? AND valid = 't' ORDER BY id ASC LIMIT ?;");
        if (!defined $sth) {
	  sendMsg("err",
	         "Cannot prepare ROE statement in function '$function_name': $DBH->errstr",
		 "Internal 'prepare' server error");
	}
	$sth->execute($last_id, $requested_type, $used_limit);
      }
    } else {
      if ($requested_type eq '_any_') {
        $sth = $DBH->prepare("SELECT * FROM events WHERE type != 'test' AND id > ? AND valid = 't' AND hostname NOT LIKE ? ORDER BY id ASC LIMIT ?;");
        if (!defined $sth) {
	  sendMsg("err",
	         "Cannot prepare ANY statement in function '$function_name': $DBH->errstr",
		 "Internal 'prepare' server error");
	}
        my ($domain) = $cn =~ /([^\.]+\.[^\.]+)$/;
        $domain = '\%' . $domain;
        $sth->execute($last_id, $domain, $used_limit);
      } else {
        $sth = $DBH->prepare("SELECT * FROM events WHERE type != 'test' AND id > ? AND type = ? AND valid = 't' AND hostname NOT LIKE ? ORDER BY id ASC LIMIT ?;");
        if (!defined $sth) {
	  sendMsg("err",
	         "Cannot prepare statement in function '$function_name': $DBH->errstr\n",
		 "Internal 'prepare' server error");
	}
        my ($domain) = $cn =~ /([^\.]+\.[^\.]+)$/;
        $domain = '\%' . $domain;
        $sth->execute($last_id, $requested_type, $domain, $used_limit);
      }
    }

    # obtain items of events stored in events table
    while (my @result = $sth->fetchrow()) {
      $id 		= $result[0];
      $detected 	= $result[1];
      $type 		= $result[3];
      $source_type 	= $result[4];
      $source	 	= $result[5];
      $target_proto	= $result[6];
      $target_port 	= $result[7];
      $attack_scale	= $result[8];
      $note 		= $result[9];
      $priority 	= $result[10];
      $timeout	 	= $result[11];
      $client_id        = $result[13];

      # obtain hostname and service of events based on client_id from clients table
      $sth = $DBH->prepare("SELECT hostname, service FROM clients WHERE client_id = ?;");
      $sth->execute($client_id);
      ($hostname, $service) = $sth->fetchrow();

      # create SOAP data object
      $event = SOAP::Data->name(event => \SOAP::Data->value(
        SOAP::Data->name(ID		=> $id),
        SOAP::Data->name(HOSTNAME	=> $hostname),
        SOAP::Data->name(SERVICE	=> $service),
        SOAP::Data->name(DETECTED	=> $detected),
        SOAP::Data->name(TYPE		=> $type),
        SOAP::Data->name(SOURCE_TYPE	=> $source_type),
        SOAP::Data->name(SOURCE		=> $source),
        SOAP::Data->name(TARGET_PROTO	=> $target_proto),
        SOAP::Data->name(TARGET_PORT	=> $target_port),
        SOAP::Data->name(ATTACK_SCALE	=> $attack_scale),
        SOAP::Data->name(NOTE		=> $note),
        SOAP::Data->name(PRIORITY	=> $priority),
        SOAP::Data->name(TIMEOUT	=> $timeout)
      ));
      push(@events, $event);
      push(@ids, $id);
    }

    # log sent ID of events
    if (scalar @events != 0) {
      if (scalar @ids == 1) {
        sendMsg("info",
	        "Sent 1 event [#$ids[0]] to [IP: '$ip'; CN(AN): $alt_names; Client_limit: '$max_rcv_events_limit', Requested_type: '$requested_type']",
	        undef);
      } else {
        sendMsg("info",
                "Sent " . scalar @ids . " events [#$ids[0] - #$ids[-1]] to [IP: '$ip'; CN(AN): $alt_names, Client_limit: '$max_rcv_events_limit', Requested_type: '$requested_type']",
	        undef);
      }
    }
    return @events;
  }
} # END of getNewEvents


#-----------------------------------------------------------------------------
# getLastId - get lastest saved event ID
#-----------------------------------------------------------------------------
sub getLastId
{
  my ($class, $arg) = @_;

  # client network information
  my $cn	= $ENV{'SSL_CLIENT_S_DN_CN'};
  my $alt_names	= getAltNames(undef);
  my $ip	= $ENV{'REMOTE_ADDR'};

  my $service		= undef;
  my $client_type	= undef;

  my $function_name = 'getLastId';

  my %client = authorizeClient($alt_names, $ip, $service, $client_type, $function_name);
  if (defined %client) {
    my $sth = $DBH->prepare("SELECT max(id) FROM events;");
    if (!defined $sth) {
      sendMsg("err",
              "Cannot prepare statement in function '$function_name': $DBH->errstr",
              "Internal 'prepare' server error");
    }
    $sth->execute;
    my $result = $sth->fetchrow();
    return $result;
  }
} # END of getLastID


#-------------------------------------------------------------------------------
# getClientInfo - get list of registered clients on Warden server
#		  by Warden client
#-------------------------------------------------------------------------------
sub getClientInfo
{
  my ($class, $data) = @_;
  my (@clients, $client);
  my ($client_id, $hostname, $registered, $requestor, $service, $client_type, $type, $receive_own_events, $description_tags, $ip_net_client);

  # client network information
  my $cn	= $ENV{'SSL_CLIENT_S_DN_CN'};
  my $alt_names	= getAltNames(undef);
  my $ip	= $ENV{'REMOTE_ADDR'};

  my $service		= undef;
  my $client_type	= undef;

  my $function_name = 'getClientInfo';

  my %client = authorizeClient($alt_names, $ip, $service, $client_type, $function_name);
  if (defined %client) {
    my $sth = $DBH->prepare("SELECT * FROM clients WHERE valid = 't' ORDER BY client_id ASC;");
    if (!defined $sth) {
      sendMsg("err",
            "Cannot prepare statement in function '$function_name': $DBH->errstr",
            "Internal 'prepare' server error");
    }
    $sth->execute;

    while ( my @result = $sth->fetchrow() ) {
      $client_id		= $result[0];
      $hostname			= $result[1];
      $registered		= $result[2];
      $requestor		= $result[3];
      $service			= $result[4];
      $client_type		= $result[5];
      $type 			= $result[6];
      $receive_own_events	= $result[7];
      $description_tags		= $result[8];
      $ip_net_client		= $result[9];

      $client = SOAP::Data->name(client => \SOAP::Data->value(
      SOAP::Data->name(CLIENT_ID		=> $client_id),
      SOAP::Data->name(HOSTNAME			=> $hostname),
      SOAP::Data->name(REGISTERED		=> $registered),
      SOAP::Data->name(REQUESTOR		=> $requestor),
      SOAP::Data->name(SERVICE			=> $service),
      SOAP::Data->name(CLIENT_TYPE		=> $client_type),
      SOAP::Data->name(TYPE			=> $type),
      SOAP::Data->name(RECEIVE_OWN_EVENTS	=> $receive_own_events),
      SOAP::Data->name(DESCRIPTION_TAGS		=> $description_tags),
      SOAP::Data->name(IP_NET_CLIENT		=> $ip_net_client),
      ));
      push(@clients, $client);
    }
    my $sum = scalar @clients;
    sendMsg("info",
            "Sent information about $sum registered clients from Warden server '$ENV{'SERVER_NAME'}'",
            undef);
    return @clients;
  }
} # END of getClientInfo

1;