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#!/usr/local/cpanel/3rdparty/bin/perl
# cpanel - scripts/sshcontrol 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
#----------------------------------------------------------------------
# This script controls a Net::OpenSSH session.
#
#It can authenticate a connection via password or SSH private key.
#
#It can connect via:
# 1) root login
# 2) user login, then su to root
# 3) user login, then sudo to root
#
#Additionally, existing connections may persist and be reused.
#
#Once connected, it can:
# 1) copy a file from/to local/remote
# 2) AS ROOT: execute an arbitrary command on the remote server
#
#Inputs:
# key/value are read from STDIN as a hash,
# serialized with Cpanel::AdminBin::Serializer::Dump()
#
#
# Required arguments:
# authuser The user as which to identify during the SSH login.
#
# host The remote host.
#
# ctl "ssh" or (usually "scp", but anything defined will do)
#
#
# Additional, optional arguments:
# external_master ctl_pass parameter for Net::OpenSSH
# Required if die_on_pid is not given.
#
# die_on_pid ID of a specific process for the SSH control process
# to watch and self-destruct upon the end of that
# process. Defaults to the script's process ID.
#
# port passed to Net::OpenSSH
#
# root_pass If authuser is "root", used to login;
# otherwise, used to escalate privileges via su.
# (Don’t submit if you mean to do sudo.)
#
# ssh_private_key_password passphrase for sshkey
#
# sshkey filename under $HOME/.ssh/
#
# stay_alive boolean; whether to keep the SSH control
# process around and pass back its PID and
# path in the response
#
# wheel_pass Used to login as a non-root user.
# If there is no root_pass, also used to escalate
# privileges via sudo.
#
#
# Additional arguments when ctl is "ssh":
# cmd if ctl is "ssh", executed AS ROOT on the remote server
#
#
# Additional arguments when ctl is "scp":
# destfile if ctl ne "ssh", passed to Cpanel::SSHControl::scp
# NOTE: If ".", value is read from the last node in the
# path from srcfile
#
# direction if ctl ne "ssh", passed to Cpanel::SSHControl::scp
#
# srcfile if ctl ne "ssh", passed to Cpanel::SSHControl::scp
#
#
#Output:
# This speaks the "protocol" that Whostmgr/Remote/Parser.pm understands.
# Note that this prints even error statuses to STDOUT.
#
#----------------------------------------------------------------------
package Script::SSHControl;
use strict;
use warnings;
use IO::Pipe ();
use Cpanel::AdminBin::Serializer ();
use Cpanel::ForkAsync ();
use Cpanel::SSHControl ();
use Cpanel::Locale::Lazy 'lh';
use Cpanel::TimeHiRes ();
use Cpanel::Exception ();
use Cpanel::Sys::Setsid::Fast ();
use Cpanel::BinCheck::Lite ();
my $ONEDAY = (86400);
my @REQUIRED_ARGS = qw( authuser host ctl );
Cpanel::BinCheck::Lite::check_argv();
my $debug = 0;
__PACKAGE__->script() unless caller();
sub script { ## no critic qw(Subroutines::ProhibitExcessComplexity)
my ($class) = @_;
local $| = 1;
local $ENV{'TERM'} = 'dumb';
my $self = {};
bless $self, $class;
my $parsed_args = Cpanel::AdminBin::Serializer::SafeLoadFile( \*STDIN );
my @missing = grep { !length $parsed_args->{$_} } @REQUIRED_ARGS;
if (@missing) {
_leave( lh()->maketext( 'Specify the [list_and_quoted,_1] [numerate,_2,parameter,parameters].', \@missing, ( scalar @missing ) ) );
}
my $escalation_method;
if ( $parsed_args->{'root_escalation_method'} && $parsed_args->{'root_escalation_method'} eq 'none' ) {
$escalation_method = 'none';
}
else {
# NB: Avoid length() here because we want to interpret
# root_pass==0 as no root password.
my $gave_root_pass = !!$parsed_args->{'root_pass'};
if ( length $parsed_args->{'wheel_pass'} ) {
if ( $parsed_args->{'authuser'} eq 'root' ) {
_leave( lh()->maketext( 'If “[_1]” is “[_2]”, you cannot specify “[_3]”.', qw(authuser root wheel_pass) ) );
}
# Just a wheel/sudo password? Gotta be sudo.
if ( !$gave_root_pass ) {
$escalation_method = 'sudo';
}
}
# Root password + non-root = su
if ($gave_root_pass) {
if ( $parsed_args->{'authuser'} ne 'root' ) {
$escalation_method = 'su';
}
}
}
my $cmd = $parsed_args->{'cmd'};
my $ssh_key = $parsed_args->{'sshkey'} ? ( ( getpwuid($>) )[7] . "/.ssh/" . $parsed_args->{sshkey} ) : undef;
my $ssh_username = $parsed_args->{'authuser'};
$parsed_args->{'die_on_pid'} ||= $$;
my $auth_info = {
'ssh_username' => $ssh_username,
'ssh_ip' => $parsed_args->{'host'},
'ssh_port' => $parsed_args->{'port'},
'root_pass' => $parsed_args->{'root_pass'} || ( $ssh_username eq 'root' ? $parsed_args->{'wheel_pass'} : undef ),
'wheel_pass' => $parsed_args->{'wheel_pass'},
'ssh_private_key_password' => $parsed_args->{'ssh_private_key_password'},
'root_escalation_method' => $escalation_method,
'ssh_private_key' => $ssh_key,
'key_or_pass' => ( $ssh_key ? 1 : 0 ),
};
my ( $status, $master_pid, $data );
my $ssh_obj;
if ( $parsed_args->{'external_master'} ) {
$0 = "sshcontrol parent: $auth_info->{'ssh_ip'} - external master";
$ssh_obj = Net::OpenSSH->new( 'child', external_master => 1, ctl_path => $parsed_args->{'external_master'} );
}
else {
$0 = "sshcontrol parent: $auth_info->{'ssh_ip'} - create connection";
}
my $keep_ssh_master = $parsed_args->{'stay_alive'} ? 1 : 0;
if ( $ssh_obj && $ssh_obj->check_master() ) {
print "Reused existing connection.\n";
$0 = "sshcontrol parent: $auth_info->{'ssh_ip'} - reused external master";
}
else {
$0 = "sshcontrol parent: $auth_info->{'ssh_ip'} - creating connection";
if ( $parsed_args->{'external_master'} ) {
$keep_ssh_master = 1;
}
( $status, $master_pid, $data ) = $self->_create_ssh_master_connection( $auth_info, $parsed_args->{'die_on_pid'} );
if ( !$status ) {
_ssh_error_to_whm_remote_error_and_leave($data);
}
$ssh_obj = Net::OpenSSH->new( 'child', external_master => 1, ctl_path => $data );
}
if ( $ssh_obj->error() ) {
my $ssh_error = $ssh_obj->error();
_ssh_error_to_whm_remote_error_and_leave($ssh_error);
}
$0 = "sshcontrol parent: $auth_info->{'ssh_ip'} - attaching to external";
my $ssh_control = Cpanel::SSHControl->new_from_external( 'debug' => 0, 'quiet' => 0, 'verbose' => 0, 'auth_info' => $auth_info, 'ssh' => $ssh_obj );
$0 = "sshcontrol parent: $auth_info->{'ssh_ip'} - attached to external";
$SIG{'TERM'} = sub {
$ssh_control->disconnect();
};
if ( $parsed_args->{ctl} eq 'ssh' ) {
$0 = "sshcontrol parent: $auth_info->{'ssh_ip'} - ssh";
my ( $status, $msg ) = $ssh_control->exec_as_root($cmd);
if ( !$status ) {
_ssh_error_to_whm_remote_error_and_leave($msg);
}
}
elsif ( $parsed_args->{'ctl'} eq 'scp' ) {
$0 = "sshcontrol parent: $auth_info->{'ssh_ip'} - scp";
my $destfile = $parsed_args->{'destfile'} eq '.' ? ( split( m{/+}, $parsed_args->{'srcfile'} ) )[-1] : $parsed_args->{'destfile'};
my ( $status, $msg ) = $ssh_control->scp(
'direction' => $parsed_args->{'direction'},
'srcfile' => $parsed_args->{'srcfile'},
'destfile' => $destfile,
);
if ( !$status ) {
_ssh_error_to_whm_remote_error_and_leave($msg);
}
elsif ( $parsed_args->{'direction'} eq 'download' && !-e $destfile ) {
_ssh_error_to_whm_remote_error_and_leave("The destination file: “$destfile” failed to download.");
}
}
else {
die "Invalid “ctl”: [$parsed_args->{'ctl'}]";
}
$self->_write_sshcontrol_info( $master_pid, $ssh_obj );
if ( !$keep_ssh_master || !$master_pid ) {
$ssh_control->disconnect_master();
}
undef $ssh_obj;
return $self;
}
sub _write_sshcontrol_info {
my ( $self, $master_pid, $ssh_obj ) = @_;
if ($master_pid) {
print "\n==sshcontrolpid=$master_pid==\n";
}
print "\n==sshcontrolpath=" . $ssh_obj->get_ctl_path() . "==\n";
return;
}
sub _leave {
my @args = @_;
print @args;
die "\n";
}
sub _create_ssh_master_connection {
my ( $self, $auth_info, $die_on_pid ) = @_;
my $ssh_pipe = IO::Pipe->new();
my $child_result;
my $sshcontrol_pid = Cpanel::ForkAsync::do_in_child(
sub {
$ssh_pipe->writer();
open( STDOUT, '>&=' . fileno($ssh_pipe) ); ## no critic qw(RequireCheckedOpen)
if ($die_on_pid) {
$0 = "sshcontrol child: $auth_info->{'ssh_ip'} - waiting on pid $die_on_pid";
}
else {
$0 = "sshcontrol child: $auth_info->{'ssh_ip'}";
}
my $ssh_control = Cpanel::SSHControl->new( 'debug' => 0, 'quiet' => 0, 'verbose' => 0, 'auth_info' => $auth_info );
{
local $@;
eval { $ssh_control->connect() };
if ($@) {
my $error_as_string = Cpanel::Exception::get_string_no_id($@);
$error_as_string =~ s/\n/ /g;
# This is going to the parent
print "\nsshcontrol:0:" . $error_as_string . "\n";
exit(1);
}
}
my $master_pid = $ssh_control->{'ssh'}->get_master_pid();
if ( !$master_pid ) {
print "\nsshcontrol:0:failed to create sshcontrol master\n";
exit(1);
}
$SIG{'HUP'} = 'IGNORE';
$SIG{'ALRM'} = $SIG{'TERM'} = sub {
$ssh_control->disconnect_master();
exit(0);
};
# This is going to the parent
print "\nsshcontrol:1:" . $ssh_control->{'ssh'}->get_ctl_path() . "\n";
Cpanel::Sys::Setsid::Fast::fast_setsid();
open( STDIN, '<', '/dev/null' ); ## no critic qw(RequireCheckedOpen)
open( STDOUT, '>', '/dev/null' ); ## no critic qw(RequireCheckedOpen)
open( STDERR, '>', '/dev/null' ); ## no critic qw(RequireCheckedOpen)
alarm($ONEDAY); # If something gets killed off expire in one day
while ( waitpid( $master_pid, 1 ) != -1 && kill( 0, $die_on_pid ) ) {
Cpanel::TimeHiRes::sleep(0.1);
}
$ssh_control->disconnect_master();
waitpid( $master_pid, 0 );
exit(0);
}
);
$ssh_pipe->reader();
while ( readline($ssh_pipe) ) {
if (m{^sshcontrol:}) { $child_result = $_; last; }
print;
}
chomp($child_result);
my ( $sshcontrol_tag, $status, $data ) = split( m{:}, $child_result, 3 );
return ( $status, $sshcontrol_pid, $data );
}
my @SSH_ERRORS;
sub _ssh_error_to_whm_remote_error_and_leave {
my ($ssh_error) = @_;
if ( !@SSH_ERRORS ) {
@SSH_ERRORS = (
[ qr{master process exited unexpectedly:\s+([^:]+).*?No such file or directory} => 'RemoteSSHMissing' ],
[ qr{No such file or directory} => 'RemoteSSHMissing' ],
[ qr{normalize shell} => 'RemoteSSHMissing' ],
[ qr{Name or service not known} => 'RemoteSSHHostNotFound' ],
[ qr{Connection timed out} => 'RemoteSSHTimeout' ],
[ qr{(scp failed)} => 'RemoteSCPError' ],
[ qr{(^scp:.*)} => 'RemoteSCPError' ],
[ qr{(Connection (?:to [^ ]+? )?closed)} => 'RemoteSSHConnectionFailed' ],
[ qr{(No route to host)} => 'RemoteSSHConnectionFailed' ],
[ qr{(Connection refused)} => 'RemoteSSHConnectionFailed' ],
[ qr{(lost connection)} => 'RemoteSSHConnectionFailed' ],
[ qr{(Failed to escalate to root)}i => 'RemoteSSHRootEscalationFailed' ],
[ qr{(timeout)}i => 'RemoteSSHTimeout' ],
[ qr{master process exited unexpectedly:\s+(.*)} => 'RemoteSSHAccessDenied' ],
#A catch-all, must be last.
[ qr<> => 'RemoteSSHAccessDenied' ],
);
}
for my $re_code (@SSH_ERRORS) {
if ( $ssh_error =~ $re_code->[0] ) {
my $raw_error = $1 || $ssh_error;
$raw_error =~ s/=//g;
$raw_error =~ s/\r*\n/ /g;
_leave("\n==sshcontrol_error=$re_code->[1]=$raw_error==\n");
}
}
# If we did not parse the error, we need to show it
# but only if we haven't already to avoid showing it twice
print $ssh_error . "\n";
#This error is meant to look a bit more "professional" than
#"Oops! We should never get here!". :)
die "Misdirected execution flow!";
}
1;