Viewing file:  shellserver.pl (4.78 KB) -rwxr-xr-x
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#!/usr/bin/perl
# Start a websocket server connected to a shell
use lib ("$ENV{'PERLLIB'}/vendor_perl");
use Net::WebSocket::Server;
use utf8;
require './xterm-lib.pl';
my ($port, $user, $dir) = @ARGV;
# Switch to the user we're running as
my @uinfo = getpwnam($user);
my ($uid, $gid);
if ($user ne "root" && !$<) {
if (!@uinfo) {
&remove_miniserv_websocket($port, $module_name);
die "User $user does not exist!";
}
$uid = $uinfo[2];
$gid = $uinfo[3];
}
else {
$uid = $gid = 0;
}
# Run the user's shell in a sub-process
&foreign_require("proc");
&clean_environment();
# Set locale
my $lang = $config{'locale'};
if ($lang) {
my @opts = ('LC_ALL', 'LANG', 'LANGUAGE');
$lang = 'en_US.UTF-8' if ($lang == 1);
foreach my $opt (@opts) {
$ENV{$opt} = &trim($lang);
}
}
# Set terminal
$ENV{'USER'} = $user;
my $config_xterm = $config{'xterm'};
$config_xterm = 'xterm-256color'
if (!$config_xterm);
$config_xterm =~ s/\+/-/;
$ENV{'TERM'} = $config_xterm;
$ENV{'HOME'} = $uinfo[7];
chdir($dir || $uinfo[7] || "/");
my $shellcmd = $uinfo[8];
my $shellname = $shellcmd;
$shellname =~ s/^.*\///;
my $shellexec = $shellcmd;
my $shelllogin = "-".$shellname;
# Check for initialization file
if ($config{'rcfile'} ne '0') {
# Load shell init default file from module root directory or custom file
my $rcdir = "$module_root_directory/rc";
my $rcfile = $config{'rcfile'} eq '1' ?
"$rcdir/.".$shellname."rc" :
$config{'rcfile'};
if ($rcfile =~ /^\~\//) {
$rcfile =~ s/^\~\///;
$rcfile = "$uinfo[7]/$rcfile";
}
if (-r $rcfile) {
if ($shellname eq 'bash') {
# Bash
$shellexec = "$shellcmd --rcfile $rcfile";
}
elsif ($shellname eq 'zsh') {
# Zsh
$ENV{'ZDOTDIR'} = $rcdir;
}
# Cannot use login shell while passing other parameters,
# and it is not necessary as we already add init files
$shelllogin = undef;
}
}
my ($shellfh, $pid) = &proc::pty_process_exec($shellexec, $uid, $gid, $shelllogin);
&reset_environment();
my $shcmd = "'$shellexec".($shelllogin ? " $shelllogin" : "")."'";
if (!$pid) {
&remove_miniserv_websocket($port, $module_name);
die "Failed to run shell with $shcmd\n";
}
else {
&error_stderr("Running shell $shcmd for user $user with pid $pid");
}
# Detach from controlling terminal
if (fork()) {
exit(0);
}
untie(*STDIN);
close(STDIN);
# Clean up when socket is terminated
$SIG{'ALRM'} = sub {
&remove_miniserv_websocket($port, $module_name);
die "timeout waiting for connection";
};
alarm(60);
&error_stderr("Listening on port $port");
my ($wsconn, $shellbuf);
Net::WebSocket::Server->new(
listen => $port,
on_connect => sub {
my ($serv, $conn) = @_;
&error_stderr("WebSocket connection established");
if ($wsconn) {
&error_stderr("Unexpected second connection to the same port");
$conn->disconnect();
return;
}
$wsconn = $conn;
alarm(0);
$conn->on(
handshake => sub {
# Is the key valid for this Webmin session?
my ($conn, $handshake) = @_;
my $key = $handshake->req->fields->{'sec-websocket-key'};
my $dsess = &encode_base64($main::session_id);
$key =~ s/\s//g;
$dsess =~ s/\s//g;
if (!$key || !$dsess || $key ne $dsess) {
&error_stderr("Key $key does not match session ID $dsess");
$conn->disconnect();
}
},
ready => sub {
my ($conn) = @_;
$conn->send_binary($shellbuf) if ($shellbuf);
},
utf8 => sub {
my ($conn, $msg) = @_;
utf8::encode($msg) if (utf8::is_utf8($msg));
# Check for resize escape sequence explicitly
if ($msg =~ /^\\033\[8;\((\d+)\);\((\d+)\)t$/) {
my ($rows, $cols) = ($1, $2);
&error_stderr("Got resize to $rows $cols");
eval {
$shellfh->set_winsize($rows, $cols);
};
# If failed make ioctl directly (TIOCSWINSZ)
# https://manpages.ubuntu.com/manpages/man2/ioctl_list.2.html
if ($@) {
ioctl($shellfh, 0x00005414, pack("s2", $rows, $cols));
}
kill('WINCH', $pid);
return;
}
if (!syswrite($shellfh, $msg, length($msg))) {
&error_stderr("Write to shell failed : $!");
&remove_miniserv_websocket($port, $module_name);
exit(1);
}
},
disconnect => sub {
&error_stderr("WebSocket connection closed");
&remove_miniserv_websocket($port, $module_name);
kill('KILL', $pid) if ($pid);
exit(0);
}
);
},
watch_readable => [
$shellfh => sub {
# Got something from the shell
my $buf;
my $ok = sysread($shellfh, $buf, 1024);
if ($ok <= 0) {
&error_stderr("End of output from shell");
&remove_miniserv_websocket($port, $module_name);
exit(0);
}
if ($wsconn) {
$wsconn->send_binary($buf);
}
else {
$shellbuf .= $buf;
}
},
],
)->start;
&error_stderr("Exited WebSocket server");
&remove_miniserv_websocket($port, $module_name);
&cleanup_miniserv_websockets([$port], $module_name);
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