#!/usr/local/cpanel/3rdparty/bin/perl

# cpanel - scripts/mailperm                        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::mailperm;

use strict;
use Digest::MD5  ();
use Getopt::Long ();
use IO::Handle   ();
use Try::Tiny;

use Cpanel::PwCache::Helpers             ();
use Cpanel::PwCache::Build               ();
use Cpanel::Exim                         ();
use Cpanel::Signal                       ();
use Cpanel::SafeFind                     ();
use Cpanel::Logger                       ();
use Cpanel::FileUtils::TouchFile         ();
use Cpanel::Rlimit                       ();
use Cpanel::AccessIds::ReducedPrivileges ();
use Cpanel::PwCache                      ();
use Cpanel::Config::LoadUserDomains      ();
use Cpanel::ConfigFiles                  ();
use Cpanel::Email::MX                    ();
use Cpanel::Email::Perms                 ();
use Cpanel::Email::Perms::System         ();
use Cpanel::Email::Perms::User           ();
use Cpanel::MailTools::DBS               ();
use Cpanel::LoginDefs                    ();
use Cpanel::Config::LoadConfig           ();

my $logger = Cpanel::Logger->new();

my @MAILDIR_FILES_TO_SKIP = qw(
  courierimapkeywords
  courierimapuiddb
  courierpop3dsizelist
  dovecot-keywords
  dovecot-uidlist
  dovecot-uidvalidity.*
  dovecot\\.index
  dovecot\\.index.cache
  dovecot\\.index.log
  dovecot\\.index.log.2
  maildirsize
  subscriptions
);
my $maildir_files_to_skip_re = join '|', @MAILDIR_FILES_TO_SKIP;

exit main(@ARGV) unless caller;

sub main {
    my (@args) = @_;
    local $@;

    my $verbose           = 0;
    my $skiplocal         = 0;
    my $skipmxcheck       = 0;
    my $skipperm          = 0;
    my $dirsonly          = 0;
    my $no_restart_cpsrvd = 0;
    my $help              = 0;

    # Argument processing
    my %arg_ops = (
        'help'              => \$help,
        'verbose'           => \$verbose,
        'skiplocaldomains'  => \$skiplocal,
        'skipmxcheck'       => \$skipmxcheck,
        'skipserverperm'    => \$skipperm,
        'dirsonly'          => \$dirsonly,
        'no-restart-cpsrvd' => \$no_restart_cpsrvd,
    );

    Getopt::Long::GetOptionsFromArray(
        \@args,
        %arg_ops,
    ) or return _usage(1);
    return _usage(0) if $help;

    my %opts = map { $_ => ${ $arg_ops{$_} } } keys %arg_ops;

    if (@args) {
        $opts{'checkuser'} = $args[-1];
    }

    my ( $status, $message ) = eval { __PACKAGE__->script(%opts) };

    if ($@) {
        print "$@\n";
        return 1;
    }

    return 0 if $status;

    if ($message) {
        print STDERR $message . "\n";
    }

    return 1;
}

sub script {
    my ( $class, %OPTS ) = @_;

    my ( $checkuser, $skiplocal, $skipmxcheck, $skipperm, $dirsonly, $verbose ) = @OPTS{qw( checkuser skiplocaldomains skipmxcheck skipserverperm dirsonly verbose)};

    return 1 if ( $ENV{'DONT_RUN_MAILPERM'} );

    Cpanel::Rlimit::set_rlimit();

    my $pidfile = '/var/run/mailperms.pid';

    my $is_global             = 0;
    my $previous_command_name = $0;
    if ($checkuser) {
        if ( !( Cpanel::PwCache::getpwnam($checkuser) )[0] ) {
            warn "!! Specified user is not a valid system account !!\n\n";
            _usage();
            return ( 0, "The specified user '$checkuser' is not a valid system account" );
        }
        $0 = 'mailperm - single user';
    }
    else {
        $is_global = 1;
        $0         = 'mailperm - global';

        require Cpanel::Unix::PID::Tiny;
        my $upid = Cpanel::Unix::PID::Tiny->new();

        if ( !$upid->pid_file($pidfile) ) {
            my $pid = $upid->get_pid_from_pidfile($pidfile);
            $logger->warn("mailperm - previous instance: [$pid]");
            $0 = $previous_command_name;
            return ( 0, 'Another mailperm instance is running' );
        }
    }

    my ( $exim_bin, $exim_version, $exim_caps ) = Cpanel::Exim::fetch_caps();
    my $needs_mail_gid_shadow = ( $exim_caps->{'dovecot'} ) ? 0 : 1;
    $Cpanel::Email::Perms::VERBOSE = $verbose;
    my $changed_external_auth = 0;

    # Signal cpsrvd to reload its config.
    # do not restart cpsrvd on a fresh install ( cpsrvd is running but is restarted later )
    #   this avoids to solve continuously "perl dependencies issues" in the exim rpm
    Cpanel::Signal::send_hup_cpsrvd() if $changed_external_auth && !$OPTS{'no-restart-cpsrvd'};

    Cpanel::Email::Perms::System::ensure_system_perms();

    if ( !$skipperm ) {
        require '/usr/local/cpanel/scripts/checkexim.pl';    ## no critic qw(RequireBarewordIncludes)
        scripts::checkexim::checkeximperms();
    }

    chmod( 0666, '/dev/null' );

    _update_local_domains( 'checkuser' => $checkuser, 'skipmxcheck' => $skipmxcheck, 'verbose' => $verbose ) if !$skiplocal;

    _set_perms( 'checkuser' => $checkuser, 'dirsonly' => $dirsonly, 'verbose' => $verbose, 'is_global' => $is_global ) if !$skipperm;

    chmod( 0666, '/dev/null' );

    $0 = $previous_command_name;

    return 1;
}

sub _update_local_domains {
    my (%OPTS) = @_;

    my ( $checkuser, $skipmxcheck, $verbose ) = @OPTS{qw( checkuser skipmxcheck verbose )};

    Cpanel::FileUtils::TouchFile::touchfile($Cpanel::ConfigFiles::REMOTEDOMAINS_FILE);
    Cpanel::FileUtils::TouchFile::touchfile($Cpanel::ConfigFiles::LOCALDOMAINS_FILE);

    my $localdomains_ref  = Cpanel::Config::LoadConfig::loadConfig( $Cpanel::ConfigFiles::LOCALDOMAINS_FILE,  undef, '' );
    my $remotedomains_ref = Cpanel::Config::LoadConfig::loadConfig( $Cpanel::ConfigFiles::REMOTEDOMAINS_FILE, undef, '' );
    my $secondarymx_ref   = Cpanel::Config::LoadConfig::loadConfig( $Cpanel::ConfigFiles::SECONDARYMX_FILE,   undef, '' );

    my $userdomains_ref = Cpanel::Config::LoadUserDomains::loaduserdomains( undef, 1 );
    my %missing_domains;

    require Cpanel::Hostname;
    my $hostname = Cpanel::Hostname::gethostname();
    $userdomains_ref->{$hostname} = 1;

    foreach my $domain ( keys %{$userdomains_ref} ) {
        if ( !exists $localdomains_ref->{$domain} && !exists $remotedomains_ref->{$domain} ) {
            $missing_domains{$domain} = 1;
        }
    }

    if ( !$skipmxcheck ) {
        require Whostmgr::DNS::MX;
        foreach my $domain ( sort keys %{$userdomains_ref} ) {
            next if ( $domain =~ m/^\*/ );

            my $user = $userdomains_ref->{$domain};
            next if ( !$user || $user eq 'root' || ( $checkuser && $checkuser ne $user ) );

            print "Checking mx configuration for $domain ($user)..." if $verbose;
            my $alwaysaccept = Cpanel::Email::MX::get_mxcheck_configuration( $domain, $user );
            print "[$alwaysaccept]..." if $verbose;

            #
            # We need to update proxysubdomains here because nothing else
            # will be doing it for us
            #
            if ( $alwaysaccept eq 'local'
                && ( !exists $localdomains_ref->{$domain} || exists $remotedomains_ref->{$domain} || exists $secondarymx_ref->{$domain} ) ) {
                Cpanel::MailTools::DBS::setup( $domain, 'localdomains' => 1, 'remotedomains' => 0, 'secondarymx' => 0, 'update_proxy_subdomains' => 1 );
            }
            elsif (( $alwaysaccept eq 'secondary' || $alwaysaccept eq 'backup' )
                && ( exists $localdomains_ref->{$domain} || !exists $remotedomains_ref->{$domain} || !exists $secondarymx_ref->{$domain} ) ) {
                Cpanel::MailTools::DBS::setup( $domain, 'localdomains' => 0, 'remotedomains' => 1, 'secondarymx' => 1, 'update_proxy_subdomains' => 1 );
            }
            elsif ( $alwaysaccept eq 'remote'
                && ( exists $localdomains_ref->{$domain} || !exists $remotedomains_ref->{$domain} || exists $secondarymx_ref->{$domain} ) ) {
                Cpanel::MailTools::DBS::setup( $domain, 'localdomains' => 0, 'remotedomains' => 1, 'secondarymx' => 0, 'update_proxy_subdomains' => 1 );
            }
            elsif ( $missing_domains{$domain} ) {
                {
                    no warnings 'once';
                    my $checkmx = Whostmgr::DNS::MX::checkmx( $domain, undef, $alwaysaccept, $Whostmgr::DNS::MX::NO_UPDATEUSERDOMAINS, $Whostmgr::DNS::MX::DO_UPDATE_PROXY_SUBDOMAINS );
                }
            }
            print "Done\n" if $verbose;
        }
    }
    else {
        foreach my $domain ( keys %missing_domains ) {
            Cpanel::MailTools::DBS::setup( $domain, 'localdomains' => 1, 'remotedomains' => 0, 'secondarymx' => 0, 'update_proxy_subdomains' => 1 );
        }
    }

    return;
}

sub _set_perms {    ## no critic (Subroutines::ProhibitExcessComplexity)
    my (%OPTS) = @_;

    my $checkuser = $OPTS{'checkuser'};
    my $dirsonly  = $OPTS{'dirsonly'} ? 1 : 0;
    my $verbose   = $OPTS{'verbose'}  ? 1 : 0;
    my $is_global = $OPTS{'is_global'} || 0;

    my $mailgid = ( Cpanel::PwCache::getpwnam('mail') )[3];

    my $pwcache_ref;
    if ($checkuser) {
        my @pw_data = Cpanel::PwCache::getpwnam($checkuser);
        $pwcache_ref = [ \@pw_data ];
    }
    else {
        Cpanel::PwCache::Build::init_passwdless_pwcache();
        Cpanel::PwCache::Helpers::no_uid_cache();    #uid cache only needed if we are going to make lots of getpwuid calls
        $pwcache_ref = Cpanel::PwCache::Build::fetch_pwcache();
    }

    Cpanel::SafeFind::find( sub { }, '/dev/null' );    #init File::Find

    my $userdomains_ref = Cpanel::Config::LoadUserDomains::loaduserdomains( undef, 0, 1 );

    my $uid_min = Cpanel::LoginDefs::get_uid_min();
    my ( $cpuser, $useruid, $usergid, $homedir );
    foreach my $pwref ( sort { $a->[0] cmp $b->[0] } grep { exists $userdomains_ref->{ $_->[0] } && $_->[2] >= $uid_min } @$pwcache_ref ) {
        ( $cpuser, $useruid, $usergid, $homedir ) = ( (@$pwref)[ 0, 2, 3, 7 ] );
        next if ( $checkuser && $cpuser ne $checkuser );

        if ( !$useruid || !$usergid || !$homedir ) {
            warn "Skipping invalid user $cpuser";
            next;
        }

        if ( exists $userdomains_ref->{$cpuser} ) {
            foreach my $domain ( @{ $userdomains_ref->{$cpuser} } ) {
                Cpanel::Email::Perms::System::ensure_domain_system_perms( $useruid, $domain );
            }
        }
        if ( -e "$homedir/mail" || -e "$homedir/etc" ) {

            Cpanel::AccessIds::ReducedPrivileges::call_as_user(
                sub {
                    local $0 = 'mailperm - ' . ( $is_global ? 'global ' : '' ) . 'processing ' . $cpuser;

                    my ( $mode, $fuid, $fgid, $safefile );
                    Cpanel::SafeFind::find(
                        {
                            'wanted' => sub {
                                return if ( !$File::Find::name || -l $File::Find::name );

                                ( $mode, $fuid, $fgid ) = ( stat(_) )[ 2, 4, 5 ];
                                ($safefile) = $File::Find::name =~ /(.*)/;
                                if ( $fuid != $useruid || ( $fgid != $usergid && $fgid != $mailgid ) ) {
                                    my $changed = chown( $useruid, $usergid, $safefile );
                                    if ($verbose) {
                                        if ($changed) {
                                            print "Fixed ownership on $File::Find::name: was ($fuid:$fgid), now ($useruid:$usergid)\n";
                                        }
                                        else {
                                            print "Unable to fix ownership on $File::Find::name: currently ($fuid:$fgid), should be ($useruid:$usergid)\n";
                                        }
                                    }
                                }
                                return
                                  if ( $File::Find::name =~ m/\/(?:$maildir_files_to_skip_re)$/
                                    || $File::Find::name =~ m/\.cppop\.cache(?:\.msgs)?$/ );

                                ( $mode, my $want ) = map { sprintf '%04o', $_ & 07777 } $mode, $Cpanel::Email::Perms::MAILDIR_PERMS;
                                if ( -d _ ) {

                                    # All dirs must now be 0751 with dovecot 2.2.
                                    # in order to avoid:
                                    #   "Renaming not supported across conflicting directory permissions."
                                    if ( $mode ne $want ) {    #all of these are ok
                                        my $changed = chmod( $Cpanel::Email::Perms::MAILDIR_PERMS, $safefile );
                                        if ($verbose) {
                                            if ($changed) {
                                                print "Fixed permissions on $File::Find::name : was ($mode), now ($want)\n";
                                            }
                                            else {
                                                print "Unable to fix permissions on $File::Find::name : currently ($mode), should be ($want)\n";
                                            }
                                        }
                                    }

                                    if ( $dirsonly && $safefile =~ m{\/\.[^\/]+\/[^\/]+$} ) {
                                        no warnings 'once';
                                        return ( $File::Find::prune = 1 );
                                    }
                                    return;
                                }

                                #NOTE: Until 11.54 this was 0660. Cobra
                                #couldn’t think of any reason why anyone
                                #but the user should be modifying the home
                                #directory, though, so we changed it to 0640.
                                #
                                elsif ( !$dirsonly && $mode ne '0640' ) {
                                    my $changed = chmod( 0640, $safefile );
                                    if ($verbose) {
                                        if ($changed) {
                                            print "Fixed permissions on $File::Find::name: was ($mode), now (0640)\n";
                                        }
                                        else {
                                            print "Unable to fix permissions on $File::Find::name: currently ($mode), should be (0640)\n";
                                        }
                                    }
                                }
                            },
                            'follow'   => 0,
                            'no_chdir' => 1
                        },
                        $homedir . '/mail'
                    );

                    return 1;
                },

                $useruid,
                $usergid,
                $mailgid
              )
              || do {
                warn "Could not setuid to $cpuser ($useruid,$usergid + $mailgid)";
              };

            try {
                Cpanel::Email::Perms::User::ensure_all_perms($homedir);
            }
            catch {
                warn $_;
            };
        }
        else {
            print "Skipping $homedir (etc and mail missing)\n";
        }
    }
    return;
}

sub _usage {
    my ($retval) = @_;
    my $fh = $retval ? \*STDERR : \*STDOUT;
    $fh->print(<<'EOM');
Usage: mailperm <modifier> <user>

Arguments:
    <user> - Optional argument to specify the scope of
        the permissions checks. The specified user must
        be a valid system account.

Modifier Flags:
    --skiplocaldomains - This optional argument bypasses
        addition of missing domains to the /etc/localdomains
        file when specified. The localdomains file specifies
        to Exim that it should always accept delivery for
        the listed domains. Remote domains are removed from
        /etc/localdomains regardless of this flag.

    --skipmxcheck - This optional argument bypasses synchronizing
        the mail exchanger setting from the cpanel users file to the
        system.

    --dirsonly - This optional flag limits setting permissions
        to only modifying directories.
        NOTE: The “maildirsize” files are always fixed if needed.

    --skipserverperm - This optional flag prevents modification
        of the mail system files used by Exim and limits the
        scope of permission modifications to the mail account
        files.

    --verbose - This optional flag signals the utility to
        report detected permissions problems per user prior
        to modifying any permissions.

    --help - display this message and exit.

EOM
    return $retval;
}

1;