name : shrink_modsec_ip_database #!/usr/local/cpanel/3rdparty/bin/perl # cpanel - scripts/shrink_modsec_ip_database Copyright 2022 cPanel, L.L.C. # All rights reserved. # copyright@cpanel.net http://cpanel.net # This code is subject to the cPanel license. Unauthorized copying is prohibited package scripts::shrink_modsec_ip_database; use strict; use warnings; use File::Temp (); use Cpanel::PwCache (); use Cpanel::FileUtils::Move (); use Cpanel::SafetyBits (); use Cpanel::SafetyBits::Chown (); use Cpanel::AccessIds (); use Cpanel::SafeRun::Object (); use Cpanel::Imports; our $MODSEC_SDBM_UTIL = '/usr/sbin/modsec-sdbm-util'; our $DEFAULT_SECDATADIR = '/var/cpanel/secdatadir'; our @DB_FILE_SUFFIXES = qw( .pag .dir ); # Database file suffixes used by modsec-sdbm-util our $NEW_DB_NAME = 'new_db'; # This name is hard-coded in modsec-sdbm-util our $DB_PERMS = 0640; # S_IRUSR | S_IWUSR | S_IRGRP our $OTHER_EXECUTE_PERMS = 01; # S_IXOTH sub new { my ( $pkg, $opts ) = @_; my $self = ref($opts) eq 'HASH' ? { %{$opts} } : {}; bless $self, $pkg; return $self; } sub as_script { my $self = shift; logger->die('as_script() is a method call.') unless ref $self eq __PACKAGE__; if ( not $ARGV[0] or $ARGV[0] ne '-x' ) { my $msg = 'To execute, use the -x flag.'; logger()->die($msg); } $self->run(); return 1; } sub run { my $self = shift; logger->die('run() is a method call.') unless ref $self eq __PACKAGE__; return 0 unless $self->_bin_check; # Bail out early and silently if the util is not installed my $databases = $self->_gather_databases(); while ( my ( $db_path, $uid ) = each %{$databases} ) { if ( ( stat($MODSEC_SDBM_UTIL) )[2] & $OTHER_EXECUTE_PERMS ) { # Can run util as "other" user? $self->_shrink_db_as_user( $uid, $db_path ); } else { # Will have to settle for doing this as root. $self->_shrink_db( $uid, $db_path ); } } return; } sub _bin_check { return -x $MODSEC_SDBM_UTIL ? 1 : 0; } sub _gather_databases { # All files that belong to the same database and that match @DB_FILE_SUFFIXES will need to have the same file owner or that database will not be in the final output my $self = shift; logger->die('_gather_databases() is a method call.') unless ref $self eq __PACKAGE__; return $self->{'databases'} if defined $self->{'databases'}; my $secdatadir = $self->_secdatadir(); my %databases; if ( opendir( my $dir_fh, $secdatadir ) ) { FILE: while ( my $filename = readdir($dir_fh) ) { SUFFIX: for my $suffix (@DB_FILE_SUFFIXES) { if ( $filename =~ m{ \A (.*) \Q$suffix\E \Z }xms ) { my $short_name = $1; # Filename without suffix my $db_path = $secdatadir . '/' . $short_name; # Database path name suitable for passing to modsec-sdbm-util next FILE if exists $databases{$db_path}; # Move along if this belongs to a database already in the collection my $owner = $self->_validate_database_files_owner($db_path); # Check if there is a full set of files for this database path if ( $self->_allowed_owner($owner) ) { $databases{$db_path} = $owner; # Verified, add it to the collection next FILE; } } } } closedir($dir_fh); } return $self->{'databases'} = \%databases; } sub _shrink_db_as_user { my ( $self, $uid, $db_path ) = @_; logger->die('_shrink_db_as_user() is a method call.') unless ref $self eq __PACKAGE__; logger->die('_shrink_db_as_user() called without expected arguments.') unless length $uid && length $db_path; return Cpanel::AccessIds::do_as_user( $uid, sub { $self->_shrink_db( $uid, $db_path ) } ); } sub _shrink_db { my ( $self, $uid, $db_path ) = @_; logger->die('_shrink_db() is a method call.') unless ref $self eq __PACKAGE__; logger->die('_shrink_db() called without expected arguments.') unless length $uid && length $db_path; my $secdatadir = $self->_secdatadir(); my $workdir = File::Temp->newdir( CLEANUP => 1, TEMPLATE => 'shrink_modsec_db_XXXXXXXX', DIR => $secdatadir ); Cpanel::SafetyBits::Chown::safe_chown_guess_gid( $uid, $workdir ) or logger->warn("Failed to chown $workdir to uid $uid"); my @original_files = $self->_get_db_files($db_path); # modsec-sdbm-util will drop $NEW_DB_NAME * @DB_FILE_SUFFIXES files into $tempdir return 0 unless $self->_call_modsec_sdbm_util( $workdir, $db_path ); # Verify new files exist and adjust perms my $new_db_path = $workdir . '/' . $NEW_DB_NAME; my @new_files = map { $new_db_path . $_ } @DB_FILE_SUFFIXES; if ( !defined $self->_validate_database_files_owner($new_db_path) ) { # root owned files = 0 logger->warn("Failed to verify the database files generated by modsec-sdbm-util in the working directory"); return 0; } $self->_set_default_perms( $uid, \@new_files ); # Move the existing files to the workdir so we can revert if the new-file move fails my @revert_files = map { $workdir . '/original' . $_ } @DB_FILE_SUFFIXES; my $can_revert = $self->_move_files( \@original_files, \@revert_files ) or logger->warn("Failed to move original files for $db_path into working dir"); # Move new files into place if ( !$self->_move_files( \@new_files, \@original_files ) ) { logger->warn("Failed to move new files into place for $db_path"); if ($can_revert) { $self->_move_files( \@revert_files, \@original_files ) or logger->warn("Failed to move backup files for $db_path from working dir to original location"); $self->_set_default_perms( $uid, \@original_files ); } else { logger->warn("Not able to restore original files for db_path"); } return 0; } # Fix up final database permissions return 0 unless $self->_set_default_perms( $uid, \@original_files ); return 1; } sub _call_modsec_sdbm_util { my ( $self, $tempdir, $db_path ) = @_; logger->die('_call_modsec_sdbm_util() is a method call.') unless ref $self eq __PACKAGE__; logger->die('_call_modsec_sdbm_util() called without expected arguments.') unless length $tempdir && length $db_path; my $run = Cpanel::SafeRun::Object->new( program => $MODSEC_SDBM_UTIL, args => [ '-D', $tempdir, '-v', '-n', $db_path ], ); # For whatever reason, if the util fails to open the specified db it doesn't exit with an error code, so parse out the error message. # It will fail to open if the file is immutable -- which is a crazy thing to do on purpose -- but it doesn't make that obvious. if ( $run->stdout() =~ m{ ^ Failed \s to \s open \s sdbm: \s (.*) $ }xms ) { logger()->warn("$MODSEC_SDBM_UTIL failed to open database (try checking all file/dir attributes): $1"); return 0; } if ( $run->CHILD_ERROR() ) { logger()->warn( "$MODSEC_SDBM_UTIL exited with non-zero status: " . join( q{ }, map { $run->$_() // () } qw( autopsy stdout stderr ) ) ); return 0; } return 1; } sub _validate_database_files_owner { # Expects a database path such as "$secdatadir/$db_name" without a suffix # Returns owner (uid) of a full set of database files if they exist, undef otherwise # Remember that root has uid 0! my ( $self, $db_path ) = @_; logger->die('_validate_database_files_owner() is a method call.') unless ref $self eq __PACKAGE__; logger->die('_validate_database_files_owner() called without expected arguments.') unless length $db_path; my $owner; for my $file ( $self->_get_db_files($db_path) ) { return unless -f $file; # All generated filenames must exist my $seen = ( stat(_) )[4]; $owner //= $seen; # Record owner of the first file we see return unless $owner == $seen; # Validation fails if any file doesn't match recorded owner } return $owner; } sub _move_files { # Move a new set of files in place. The indexes of the source and dest lists of files are expected to correlate directly for the rename. # For example, $source_files->[0] will be renamed to $dest_files->[0]. my ( $self, $source_files, $dest_files ) = @_; logger->die('_move_files() is a method call.') unless ref $self eq __PACKAGE__; logger->die('_move_files() called without expected arguments.') unless ref($source_files) eq 'ARRAY' && ref($dest_files) eq 'ARRAY'; logger->die('_move_files() called without file lists of equal count.') unless scalar @$source_files == scalar @$dest_files; unlink @$dest_files; # Though they would be overwritten by safemv, there's less chance for a mixture of old and new files if we remove all now and then something goes wrong later my $result = 1; while ( my ( $index, $source_file ) = each @$source_files ) { my $dest_file = $dest_files->[$index]; if ( !Cpanel::FileUtils::Move::safemv( '-f', $source_file, $dest_file ) ) { logger->warn("Failed to move $source_file to $dest_file"); $result = 0; # Overall fail if any file doesn't move } } return $result; } sub _set_default_perms { my ( $self, $uid, $files ) = @_; logger->die('_set_default_perms() is a method call.') unless ref $self eq __PACKAGE__; logger->die('_set_default_perms() called without expected arguments.') unless length $uid && ref($files) eq 'ARRAY' && scalar @$files; for my $file (@$files) { if ( !-f $file ) { logger->warn("Missing expected file $file while trying to update permissions"); return 0; # Must bail out if all of the expected files don't exist. } Cpanel::SafetyBits::safe_chmod( $DB_PERMS, $uid, $file ) or logger->warn("Failed to chmod $file"); Cpanel::SafetyBits::Chown::safe_chown_guess_gid( $uid, $file ) or logger->warn("Failed to chown $file to uid $uid"); } return 1; } sub _get_db_files { # Expects a database path (i.e. "$secdatadir/$shortname") without a suffix # Generates list of files with known suffixes appended to database path (does not verify existence) my ( $self, $path ) = @_; logger->die('_get_db_files() is a method call.') unless ref $self eq __PACKAGE__; logger->die('_get_db_files() called without expected arguments.') unless length $path; return map { $path . $_ } @DB_FILE_SUFFIXES; } sub _allowed_owner { # If this is expanded to allow any user, ensure that $owner and its gid exists in Cpanel::PwCache to avoid death by Cpanel::SafetyBits::Chown::safe_chown_guess_gid my ( $self, $owner ) = @_; logger->die('_allowed_owner() is a method call.') unless ref $self eq __PACKAGE__; # undef $owner is not an implementation error here, it simply means the owner couldn't be determined or is intentionally being skipped. return unless defined $owner; my $nobody_uid = $self->{'nobody_uid'} //= ( Cpanel::PwCache::getpwnam('nobody') )[2]; return unless defined $nobody_uid; return 1 if $owner == $nobody_uid; return 0; } sub _secdatadir { my $self = shift; logger->die('_secdatadir() is a method call.') unless ref $self eq __PACKAGE__; $self->{'secdatadir'} //= $DEFAULT_SECDATADIR; logger->die('Unable to determine secdatadir.') unless length $self->{'secdatadir'}; return $self->{'secdatadir'}; } if ( not caller() ) { my $shrink = scripts::shrink_modsec_ip_database->new(); $shrink->as_script; exit 0; } 1; __END__ =head1 NAME /scripts/shrink_modsec_ip_database =head1 USAGE AS A SCRIPT /scripts/shrink_modsec_ip_database -x =head2 AS A LIBRARY This script is internally written as a modulino, which means it can be C<require>'d: use strict; require q{/scripts/shrink_modsec_ip_database}; my $shrink = scripts::shrink_modsec_ip_database->new(); $shrink->run(); =head1 REQUIRED ARGUMENTS None =head1 OPTIONS =over 4 =item -x Use this option to actually run the script, otherwise it will warn and return without doing anything. =back =head1 DESCRIPTION This script is called by C<scripts/maintenance>, and its purpose is to shrink ModSecurity database files by removing expired entries. =head1 DIAGNOSTICS None =head1 EXIT STATUS Exit status is 0 (success) unless an unexpected error occurs. =head1 DEPENDENCIES This script relies on C</usr/sbin/modsec-sdbm-util> to be installed, and in order to be useful, C<ModSecurity> must be installed and be enabled. =head1 INCOMPATIBILITIES None =head1 BUGS AND LIMITATIONS None =head1 LICENSE AND COPYRIGHT Copyright 2022 cPanel, L.L.C.