setuid 处的不安全 ENV 变量

Question

我正在使用此代码，当我从 root 运行它时它工作正常，但是当我将 root 权限设置为它时，它会抛出一个错误，提示“insecure $ENV{PATH} at line system”perl $qtool -d $mqueue_directory* $queue_id";"

我的脚本在路径 /scripts/deferred.pl

#!/usr/bin/perl

use strict;

my $qtool = "/usr/local/bin/qtool.pl";
my $mqueue_directory = "/var/spool/mqueue";
my $messages_removed = 0;
my @rf_id;
my @date;
my $temp
my @write_array;
my $to;
my $from;
use Untaint;
use File::Find;
# Recursively find all files and directories in $mqueue_directory
use Untaint;
find(\&wanted, $mqueue_directory);

sub wanted {
   # Is this a qf* file?
   if ( /^qf(\w{14})/ ) {
      my $qf_file = $_;
      my $queue_id = $1;
      my $deferred = 0;
      my $from_postmaster = 0;
      my $delivery_failure = 0;
      my $junk_mail = 0;
      open (QF_FILE, $_);
      while(<QF_FILE>) {
         $deferred = 1 if ( /^MTemporarily/ | /^Mhost map: lookup/ | /^MUser unknown/ );
         $delivery_failure = 1 if \
            ( /^H\?\?Subject: DELIVERY FAILURE: (User|Recipient)/ );
         if ( $deferred && $from_postmaster && $delivery_failure ) {
            $junk_mail = 1;
                     }
      $temp=$qf_file.':';
      if($junk_mail){
      while(<QF_FILE>){
      chomp;
      if(/rRFC822;/){
      $temp.=subdtr($_,9)
      }
      if(/H?D?Date:/){
      $temp.=':'.substr($_,10);
      push @write_array, $temp."\n";
      }
      }
      }
      }
      close (QF_FILE);
      my $subqueue_id = substr($queue_id,9);
      if ($junk_mail) {
         print "Removing $queue_id...\n";
         system "perl $qtool -d $mqueue_directory*$queue_id";
         $messages_removed++;
      }
   }
}
open (MYFILE,">/scripts/mail.txt");
print MYFILE "@write_array";
close (MYFILE);
$to='yagya@mydomain.in';
$from='system@mydomain.in';
$subject='deleted mails';

open(MAIL,"|/usr/sbin/sendmail -t");
print MAIL "To: $to\n";
print MAIL "From: $from\n";
print MAIL "Subject: $subject\n\n";
print MAIL "@write_array\n";
close(MAIL);

print "\n$messages_removed total \"double bounce\" message(s) removed from ";
print "mail queue.\n";

Answer 1

Setuid 程序自动在污点模式下运行。这一切都在perlsec 中进行了解释，包括您的错误消息中的文本。通常，如果您将错误消息粘贴到搜索引擎中，您会很快找到如何处理它。您可能还会看到Insecure $ENV{ENV} while running with -T switch。