#
#   MailScanner - SMTP E-Mail Virus Scanner
#   Copyright (C) 2002  Julian Field
#
#   $Id: Quarantine.pm 4714 2009-04-01 16:12:10Z sysjkf $
#
#   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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
#   The author, Julian Field, can be contacted by email at
#      Jules@JulianField.net
#   or by paper mail at
#      Julian Field
#      Dept of Electronics & Computer Science
#      University of Southampton
#      Southampton
#      SO17 1BJ
#      United Kingdom
#

package MailScanner::Quarantine;

use strict 'vars';
use strict 'refs';
no  strict 'subs'; # Allow bare words for parameter %'s

use File::Copy;
use File::Temp qw ( tempfile tempdir );

use vars qw($VERSION);

### The package version, both in 1.23 style *and* usable by MakeMaker:
$VERSION = substr q$Revision: 4714 $, 10;

# Attributes are
#
# $dir			set by new The root of the quarantine tree
# $uid			set by new The UID to change files to
# $gid			set by new The GID to change files to
# $changeowner		set by new Should I try to chown the files at all?
# $fileumask		set by new Umask to use before creating files
# $dirumask		set by new Umask to use before mkdir 0777;
#

# Constructor.
# Takes dir => directory queue resides in
sub new {
  my $type = shift;
  my $this = {};

  # Work out the uid and gid they want to use for the quarantine dir
  my($currentuid, $currentgid) = ($<, $();
  my($destuid, $destuname, $destgid, $destgname);
  $destuname = MailScanner::Config::Value('quarantineuser') ||
               MailScanner::Config::Value('runasuser');
  $destgname = MailScanner::Config::Value('quarantinegroup') ||
               MailScanner::Config::Value('runasgroup');
  $this->{changeowner} = 0;
  if ($destuname ne "" || $destgname ne "") {
    $destuid = $destuname?getpwnam($destuname):0;
    $destgid = $destgname?getgrnam($destgname):0;
    $this->{gid} = $destgid if $destgid != $currentgid;
    $this->{uid} = $destuid if $destuid != $currentuid;
  } else {
    $destuid = 0;
    $destgid = 0;
    $this->{gid} = 0;
    $this->{uid} = 0;
  }

  # Create a test file to try with chown
  my($testfn, $testfh, $worked);
  #MailScanner::Config::Value('lockfiledir') || '/var/spool/MailScanner/incoming/Locks';
  ($testfh, $testfn) = tempfile('MS.ownertest.XXXXXX', DIR => '/tmp')
    or MailScanner::Log::WarnLog('Could not test file ownership abilities on %s, please delete the file', $testfn);
  print $testfh "Testing file owner and group permissions for MailScanner\n";
  $testfh->close;

  # Now test the changes to see if we can do them
  my($changeuid, $changegid);
  if ($destgid != $currentgid) {
    $worked = chown $currentuid, $destgid, $testfn;
    if ($worked) {
      #print STDERR "Can change the GID of the quarantine\n";
      $changegid = 1;
    }
  } else {
    $changegid = 0;
  }
  if ($destuid != $currentuid) {
    $worked = chown $destuid, $destgid, $testfn;
    if ($worked) {
      #print STDERR "Can change the UID of the quarantine\n";
      $changeuid = 1;
    }
  } else {
    $changeuid = 0;
  }
  unlink $testfn;

  # Finally store the results
  $this->{uid} = $currentuid unless $changeuid;
  $this->{gid} = $currentgid unless $changegid;
  $this->{changeowner} = 1 if $changeuid || $changegid;

  # Now to work out the new umask
  # Default is 0600 for files, which gives 0700 for directories
  my($perms, $dirumask, $fileumask);
  $perms = MailScanner::Config::Value('quarantineperms') || '0600';
  $perms = sprintf "0%lo", $perms unless $perms =~ /^0/; # Make it octal
  $dirumask = $perms;
  $dirumask =~ s/[1-7]/$&|1/ge; # If they want r or w give them x too
  $this->{dirumask}  = oct($dirumask) ^ 0777;
  $fileumask = $perms;
  $this->{fileumask} = oct($fileumask) ^ 0777;
  #print STDERR sprintf("File Umask = 0%lo\n", $this->{fileumask});
  #print STDERR sprintf("Dir  Umask = 0%lo\n", $this->{dirumask});

  my($dir);
  $dir = MailScanner::Config::Value('quarantinedir');
  #print STDERR "Creating quarantine at dir $dir\n";

  umask $this->{dirumask};
  mkdir($dir, 0777) unless -d $dir;
  chown $this->{uid}, $this->{gid}, $dir if $this->{changeowner};
  umask 0077; # As this is in startup code, assume something daft will happen

  # Cannot make today's directory here as the date will change while the
  # program is running.

  $this->{dir} = $dir;
  bless $this, $type;
  return $this;
}


# Work out the name of today's directory segment
sub TodayDir {
  my($day, $month, $year);

  # Create today's directory if necessary
  ($day, $month, $year) = (localtime)[3,4,5];
  $month++;
  $year += 1900;
  return sprintf("%04d%02d%02d", $year, $month, $day);
}


# Store infected files in the quarantine
sub StoreInfections {
  my $this = shift;
  my($message) = @_;

  my($qdir, $todaydir, $msgdir, $uid, $gid, $changeowner, @chownlist);

  #print STDERR "In StoreInfections\n";

  # Create today's directory if necessary
  #$todaydir = $this->{dir} . '/' . TodayDir();
  $qdir = MailScanner::Config::Value('quarantinedir', $message);
  $todaydir = $qdir . '/' .  $message->{datenumber}; # TodayDir();
  $uid = $this->{uid};
  $gid = $this->{gid};
  $changeowner = $this->{changeowner};
  umask $this->{dirumask};
  unless (-d $qdir) {
    mkdir($qdir, 0777);
    chown $uid, $gid, $qdir if $changeowner;
  }
  unless (-d $todaydir) {
    mkdir($todaydir, 0777);
    chown $uid, $gid, $todaydir if $changeowner;
  }
    
  # Create directory for this message
  $msgdir = "$todaydir/" . $message->{id};
  unless (-d $msgdir) {
    mkdir($msgdir, 0777);
    chown $uid, $gid, $msgdir if $changeowner;
  }

  # Is there a report for the whole message? If so, save the whole thing.
  # Also save the whole thing if they have asked us to quarantine entire
  # messages, not just infections.
  umask $this->{fileumask};
  if ($message->{allreports}{""} ||
      MailScanner::Config::Value('quarantinewholemessage',$message) =~ /1/) {
    #print STDERR "Saving entire message to $msgdir\n";
    MailScanner::Log::NoticeLog("Saved entire message to $msgdir");
    $message->{store}->CopyEntireMessage($message, $msgdir, 'message',
                                         $uid, $gid, $changeowner);
    push @chownlist, "$msgdir/message" if -f "$msgdir/message";
    # Remember where we archived it, so we can put it in postmaster notice
    push @{$message->{quarantineplaces}}, $msgdir;
    #print STDERR "1 Added $msgdir to quarantine\n";
  }

  # Now just quarantine the infected attachment files.
  my($indir, $attachment, $notype, $report);
  $indir = $global::MS->{work}->{dir} . '/' . $message->{id};
  while(($attachment, $report) = each %{$message->{allreports}}) {
    # Skip reports pertaining to entire message, we've done those.
    # These $attachments contain type indicators
    next unless $attachment;

    # Get the attachment name without the type indicator, won't store it!
    $notype = substr($attachment,1);

    if ($message->{deleteattach}{$attachment}) {
      MailScanner::Log::NoticeLog("Deleted infected \"%s\"", $notype);
    } else {
      #print STDERR "Quarantining $attachment to $msgdir\n";
      MailScanner::Log::NoticeLog("Saved infected \"%s\" to %s", $notype,
                                $msgdir);

      # May be faster to do this with a Perl module File::Copy
      #system($global::cp . " -p \"$indir/$attachment\" \"$msgdir/$attachment\"");
      copy("$indir/$attachment", "$msgdir/$notype");
      push @chownlist, "$msgdir/$notype";
      # Remember where we archived it, so we can put it in postmaster notice
      push @{$message->{quarantineplaces}}, $msgdir;
      #print STDERR "2 Added $msgdir to quarantine\n";
    }
  }
  chown $uid, $gid, @chownlist if @chownlist && $changeowner;

  # Reset the umask to safe value
  umask 0077;
}