use crate::{
audit::{
AuditLog, AuditLogAction, LoginAttemptEvent, OpenDirectTcpIpEvent, OpenX11Event,
PtyRequestEvent, X11RequestEvent,
},
audit::{
SignalEvent, SubsystemRequestEvent, TcpIpForwardEvent, WindowAdjustedEvent,
WindowChangeRequestEvent,
},
config::Config,
file_system::FileSystem,
state::State,
subsystem::{self, shell::Shell, Subsystem as SubsystemTrait},
};
use futures::{
future::{BoxFuture, InspectErr},
FutureExt, TryFutureExt,
};
use std::{
borrow::Cow,
collections::HashMap,
future::Future,
net::SocketAddr,
pin::Pin,
sync::Arc,
task::{Context, Poll},
};
use thrussh::{
server::{Auth, Response, Session},
ChannelId, Pty, Sig,
};
use thrussh_keys::key::PublicKey;
use tokio::sync::mpsc::UnboundedSender;
use tokio::sync::Mutex;
use tracing::{debug, error, info, info_span, instrument::Instrumented, Instrument, Span};
pub static KEYBOARD_INTERACTIVE_PROMPT: &[(Cow<'static, str>, bool)] =
&[(Cow::Borrowed("Password: "), false)];
#[derive(Clone)]
pub struct Server {
config: Arc<Config>,
state: Arc<State>,
hostname: &'static str,
audit_send: UnboundedSender<AuditLog>,
}
impl Server {
pub fn new(
hostname: &'static str,
config: Arc<Config>,
audit_send: UnboundedSender<AuditLog>,
) -> Self {
Self {
config,
hostname,
state: Arc::new(State::default()),
audit_send,
}
}
}
impl thrussh::server::Server for Server {
type Handler = Connection;
fn new(&mut self, peer_addr: Option<SocketAddr>) -> Self::Handler {
let connection_id = uuid::Uuid::new_v4();
Connection {
span: info_span!("connection", ?peer_addr, %connection_id),
server: self.clone(),
audit_log: AuditLog {
connection_id,
host: Cow::Borrowed(self.hostname),
peer_address: peer_addr,
..AuditLog::default()
},
username: None,
file_system: None,
subsystem: HashMap::new(),
}
}
}
pub struct Connection {
span: Span,
server: Server,
audit_log: AuditLog,
username: Option<String>,
file_system: Option<FileSystem>,
subsystem: HashMap<ChannelId, Arc<Mutex<Subsystem>>>,
}
impl Connection {
pub fn username(&self) -> &str {
self.username.as_deref().unwrap_or("root")
}
pub fn file_system(&mut self) -> &mut FileSystem {
if self.file_system.is_none() {
self.file_system = Some(FileSystem::new(self.username()));
}
self.file_system.as_mut().unwrap()
}
pub fn audit_log(&mut self) -> &mut AuditLog {
&mut self.audit_log
}
fn try_login(&mut self, user: &str, password: &str) -> bool {
self.username = Some(user.to_string());
let res = if self
.server
.state
.previously_accepted_passwords
.seen(user, password)
{
info!(user, password, "Accepted login due to it being used before");
true
} else if fastrand::f64() <= self.server.config.access_probability {
info!(user, password, "Accepted login randomly");
self.server
.state
.previously_accepted_passwords
.store(user, password);
true
} else {
info!(?user, ?password, "Rejected login");
false
};
self.audit_log.push_action(AuditLogAction::LoginAttempt(
LoginAttemptEvent::UsernamePassword {
username: Box::from(user),
password: Box::from(password),
},
));
res
}
}
impl thrussh::server::Handler for Connection {
type Error = anyhow::Error;
type FutureAuth = HandlerFuture<Auth>;
type FutureUnit = HandlerFuture<Session>;
type FutureBool =
ServerFuture<Self::Error, BoxFuture<'static, Result<(Self, Session, bool), Self::Error>>>;
fn finished_auth(self, auth: Auth) -> Self::FutureAuth {
let span = info_span!(parent: &self.span, "finished_auth");
futures::future::ok((self, auth)).boxed().wrap(span)
}
fn finished_bool(self, b: bool, session: Session) -> Self::FutureBool {
let span = info_span!(parent: &self.span, "finished_bool");
let _entered = span.enter();
futures::future::ok((self, session, b))
.boxed()
.wrap(Span::current())
}
fn finished(self, session: Session) -> Self::FutureUnit {
let span = info_span!(parent: &self.span, "finished");
let _entered = span.enter();
futures::future::ok((self, session))
.boxed()
.wrap(Span::current())
}
fn auth_none(self, _user: &str) -> Self::FutureAuth {
let span = info_span!(parent: &self.span, "auth_none");
self.finished_auth(Auth::UnsupportedMethod)
.boxed()
.wrap(span)
}
fn auth_password(mut self, user: &str, password: &str) -> Self::FutureAuth {
let span = info_span!(parent: &self.span, "auth_password");
let _entered = span.enter();
let res = if self.try_login(user, password) {
Auth::Accept
} else {
Auth::Reject
};
self.finished_auth(res)
}
fn auth_publickey(mut self, _user: &str, public_key: &PublicKey) -> Self::FutureAuth {
let span = info_span!(parent: &self.span, "auth_publickey");
let _entered = span.enter();
let kind = public_key.name();
let fingerprint = public_key.fingerprint();
self.audit_log
.push_action(AuditLogAction::LoginAttempt(LoginAttemptEvent::PublicKey {
kind: Cow::Borrowed(kind),
fingerprint: Box::from(fingerprint),
}));
self.finished_auth(Auth::Reject)
.boxed()
.wrap(Span::current())
}
fn auth_keyboard_interactive(
mut self,
user: &str,
_submethods: &str,
mut response: Option<Response>,
) -> Self::FutureAuth {
let span = info_span!(parent: &self.span, "auth_keyboard_interactive");
let _entered = span.enter();
let result = if let Some(password) = response
.as_mut()
.and_then(Response::next)
.map(String::from_utf8_lossy)
{
if self.try_login(user, password.as_ref()) {
Auth::Accept
} else {
Auth::Reject
}
} else {
debug!("Client is attempting keyboard-interactive, obliging");
Auth::Partial {
name: "".into(),
instructions: "".into(),
prompts: KEYBOARD_INTERACTIVE_PROMPT.into(),
}
};
self.finished_auth(result)
}
fn channel_close(self, channel: ChannelId, mut session: Session) -> Self::FutureUnit {
let span = info_span!(parent: &self.span, "channel_close");
let _entered = span.enter();
session.channel_success(channel);
self.finished(session).boxed().wrap(Span::current())
}
fn channel_eof(mut self, channel: ChannelId, mut session: Session) -> Self::FutureUnit {
let span = info_span!(parent: &self.span, "channel_eof");
let _entered = span.enter();
if self.subsystem.remove(&channel).is_some() {
session.exit_status_request(channel, 0);
session.channel_success(channel);
} else {
session.channel_failure(channel);
}
session.close(channel);
self.finished(session).boxed().wrap(Span::current())
}
fn channel_open_session(self, channel: ChannelId, mut session: Session) -> Self::FutureUnit {
let span = info_span!(parent: &self.span, "channel_open_session");
let _entered = span.enter();
session.channel_success(channel);
self.finished(session).boxed().wrap(Span::current())
}
fn channel_open_x11(
mut self,
channel: ChannelId,
originator_address: &str,
originator_port: u32,
mut session: Session,
) -> Self::FutureUnit {
let span = info_span!(parent: &self.span, "channel_open_x11");
let _entered = span.enter();
self.audit_log
.push_action(AuditLogAction::OpenX11(OpenX11Event {
originator_address: Box::from(originator_address),
originator_port,
}));
session.channel_failure(channel);
self.finished(session).boxed().wrap(Span::current())
}
fn channel_open_direct_tcpip(
mut self,
channel: ChannelId,
host_to_connect: &str,
port_to_connect: u32,
originator_address: &str,
originator_port: u32,
mut session: Session,
) -> Self::FutureUnit {
let span = info_span!(parent: &self.span, "channel_open_direct_tcpip");
let _entered = span.enter();
self.audit_log
.push_action(AuditLogAction::OpenDirectTcpIp(OpenDirectTcpIpEvent {
host_to_connect: Box::from(host_to_connect),
port_to_connect,
originator_address: Box::from(originator_address),
originator_port,
}));
session.channel_failure(channel);
self.finished(session).boxed().wrap(Span::current())
}
fn data(mut self, channel: ChannelId, data: &[u8], mut session: Session) -> Self::FutureUnit {
let span = info_span!(parent: &self.span, "data");
let _entered = span.enter();
let subsystem = self.subsystem.get(&channel).unwrap().clone();
let data = data.to_vec();
async move {
let mut subsystem = subsystem.lock().await;
match &mut *subsystem {
Subsystem::Shell(ref mut inner) => {
inner.data(&mut self, channel, &data, &mut session).await;
}
Subsystem::Sftp(ref mut inner) => {
inner.data(&mut self, channel, &data, &mut session).await;
}
}
self.finished(session).await
}
.boxed()
.wrap(Span::current())
}
fn extended_data(
self,
_channel: ChannelId,
_code: u32,
_data: &[u8],
session: Session,
) -> Self::FutureUnit {
let span = info_span!(parent: &self.span, "extended_data");
let _entered = span.enter();
self.finished(session).boxed().wrap(Span::current())
}
fn window_adjusted(
mut self,
_channel: ChannelId,
new_window_size: usize,
session: Session,
) -> Self::FutureUnit {
let span = info_span!(parent: &self.span, "window_adjusted");
let _entered = span.enter();
self.audit_log
.push_action(AuditLogAction::WindowAdjusted(WindowAdjustedEvent {
new_size: new_window_size,
}));
self.finished(session).boxed().wrap(Span::current())
}
fn adjust_window(&mut self, _channel: ChannelId, current: u32) -> u32 {
let span = info_span!(parent: &self.span, "adjust_window");
let _entered = span.enter();
current
}
fn pty_request(
mut self,
channel: ChannelId,
term: &str,
col_width: u32,
row_height: u32,
pix_width: u32,
pix_height: u32,
modes: &[(Pty, u32)],
mut session: Session,
) -> Self::FutureUnit {
let span = info_span!(parent: &self.span, "pty_request");
let _entered = span.enter();
self.audit_log
.push_action(AuditLogAction::PtyRequest(PtyRequestEvent {
term: Box::from(term),
col_width,
row_height,
pix_width,
pix_height,
modes: Box::from(
modes
.iter()
.copied()
.map(|(pty, val)| (pty as u8, val))
.collect::<Vec<_>>(),
),
}));
session.channel_failure(channel);
self.finished(session).boxed().wrap(Span::current())
}
fn x11_request(
mut self,
channel: ChannelId,
single_connection: bool,
x11_auth_protocol: &str,
x11_auth_cookie: &str,
x11_screen_number: u32,
mut session: Session,
) -> Self::FutureUnit {
let span = info_span!(parent: &self.span, "x11_request");
let _entered = span.enter();
self.audit_log
.push_action(AuditLogAction::X11Request(X11RequestEvent {
single_connection,
x11_auth_protocol: Box::from(x11_auth_protocol),
x11_auth_cookie: Box::from(x11_auth_cookie),
x11_screen_number,
}));
session.channel_failure(channel);
self.finished(session).boxed().wrap(Span::current())
}
fn env_request(
mut self,
channel: ChannelId,
variable_name: &str,
variable_value: &str,
mut session: Session,
) -> Self::FutureUnit {
let span = info_span!(parent: &self.span, "env_request");
let _entered = span.enter();
self.audit_log
.environment_variables
.push((Box::from(variable_name), Box::from(variable_value)));
session.channel_success(channel);
self.finished(session).boxed().wrap(Span::current())
}
fn shell_request(mut self, channel: ChannelId, mut session: Session) -> Self::FutureUnit {
let span = info_span!(parent: &self.span, "shell_request");
let _entered = span.enter();
self.audit_log.push_action(AuditLogAction::ShellRequested);
let shell = Shell::new(true, channel, &mut session);
self.subsystem
.insert(channel, Arc::new(Mutex::new(Subsystem::Shell(shell))));
session.channel_success(channel);
self.finished(session).boxed().wrap(Span::current())
}
fn exec_request(
mut self,
channel: ChannelId,
data: &[u8],
mut session: Session,
) -> Self::FutureUnit {
let span = info_span!(parent: &self.span, "exec_request");
let _entered = span.enter();
let data = data.to_vec();
async move {
let mut shell = Shell::new(false, channel, &mut session);
shell.data(&mut self, channel, &data, &mut session).await;
self.subsystem
.insert(channel, Arc::new(Mutex::new(Subsystem::Shell(shell))));
session.channel_success(channel);
self.finished(session).await
}
.boxed()
.wrap(Span::current())
}
fn subsystem_request(
mut self,
channel: ChannelId,
name: &str,
mut session: Session,
) -> Self::FutureUnit {
let span = info_span!(parent: &self.span, "subsystem_request");
let _entered = span.enter();
self.audit_log
.push_action(AuditLogAction::SubsystemRequest(SubsystemRequestEvent {
name: Box::from(name),
}));
let subsystem = match name {
subsystem::sftp::Sftp::NAME => Some(Subsystem::Sftp(subsystem::sftp::Sftp::default())),
_ => None,
};
if let Some(subsystem) = subsystem {
self.subsystem
.insert(channel, Arc::new(Mutex::new(subsystem)));
session.channel_success(channel);
} else {
session.channel_failure(channel);
}
self.finished(session).boxed().wrap(Span::current())
}
fn window_change_request(
mut self,
channel: ChannelId,
col_width: u32,
row_height: u32,
pix_width: u32,
pix_height: u32,
mut session: Session,
) -> Self::FutureUnit {
let span = info_span!(parent: &self.span, "window_change_request");
let _entered = span.enter();
self.audit_log
.push_action(AuditLogAction::WindowChangeRequest(
WindowChangeRequestEvent {
col_width,
row_height,
pix_width,
pix_height,
},
));
session.channel_success(channel);
self.finished(session).boxed().wrap(Span::current())
}
fn signal(
mut self,
_channel: ChannelId,
signal_name: Sig,
session: Session,
) -> Self::FutureUnit {
let span = info_span!(parent: &self.span, "signal");
let _entered = span.enter();
self.audit_log
.push_action(AuditLogAction::Signal(SignalEvent {
name: format!("{signal_name:?}").into(),
}));
self.finished(session).boxed().wrap(Span::current())
}
fn tcpip_forward(mut self, address: &str, port: u32, session: Session) -> Self::FutureBool {
let span = info_span!(parent: &self.span, "tcpip_forward");
let _entered = span.enter();
self.audit_log
.push_action(AuditLogAction::TcpIpForward(TcpIpForwardEvent {
address: Box::from(address),
port,
}));
self.finished_bool(false, session)
.boxed()
.wrap(Span::current())
}
fn cancel_tcpip_forward(
mut self,
address: &str,
port: u32,
session: Session,
) -> Self::FutureBool {
let span = info_span!(parent: &self.span, "cancel_tcpip_forward");
let _entered = span.enter();
self.audit_log
.push_action(AuditLogAction::CancelTcpIpForward(TcpIpForwardEvent {
address: Box::from(address),
port,
}));
self.finished_bool(false, session)
.boxed()
.wrap(Span::current())
}
}
impl Drop for Connection {
fn drop(&mut self) {
let span = info_span!(parent: &self.span, "drop");
let _entered = span.enter();
info!("Connection closed");
let _res = self
.server
.audit_send
.send(std::mem::take(&mut self.audit_log));
}
}
#[derive(Debug, Clone)]
pub enum Subsystem {
Shell(subsystem::shell::Shell),
Sftp(subsystem::sftp::Sftp),
}
type HandlerResult<T> = Result<T, <Connection as thrussh::server::Handler>::Error>;
type HandlerFuture<T> = ServerFuture<
<Connection as thrussh::server::Handler>::Error,
BoxFuture<'static, HandlerResult<(Connection, T)>>,
>;
pub trait WrapFuture: Sized {
type Ok;
type Err;
fn wrap(self, span: Span) -> ServerFuture<Self::Err, Self>;
}
impl<T, F: Future<Output = Result<T, anyhow::Error>>> WrapFuture for F {
type Ok = T;
type Err = anyhow::Error;
fn wrap(self, span: Span) -> ServerFuture<Self::Err, Self> {
ServerFuture(
self.inspect_err(log_err as fn(&anyhow::Error))
.instrument(span),
)
}
}
fn log_err(e: &anyhow::Error) {
error!("Connection closed due to: {}", e);
}
#[allow(clippy::type_complexity)]
pub struct ServerFuture<E, F>(Instrumented<InspectErr<F, fn(&E)>>);
impl<T, E, F: Future<Output = Result<T, E>> + Unpin> Future for ServerFuture<E, F> {
type Output = F::Output;
fn poll(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
Pin::new(&mut self.0).poll(cx)
}
}