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use crate::session::SessionEvent;
use anyhow::Context;
use smol::channel::{bounded, Sender};
#[derive(Debug)]
pub struct AuthenticationPrompt {
pub prompt: String,
pub echo: bool,
}
#[derive(Debug)]
pub struct AuthenticationEvent {
pub username: String,
pub instructions: String,
pub prompts: Vec<AuthenticationPrompt>,
pub(crate) reply: Sender<Vec<String>>,
}
impl AuthenticationEvent {
pub async fn answer(self, answers: Vec<String>) -> anyhow::Result<()> {
Ok(self.reply.send(answers).await?)
}
pub fn try_answer(self, answers: Vec<String>) -> anyhow::Result<()> {
Ok(self.reply.try_send(answers)?)
}
}
impl crate::sessioninner::SessionInner {
#[cfg(feature = "ssh2")]
fn agent_auth(&mut self, sess: &ssh2::Session, user: &str) -> anyhow::Result<bool> {
if let Some(only) = self.config.get("identitiesonly") {
if only == "yes" {
log::trace!("Skipping agent auth because identitiesonly=yes");
return Ok(false);
}
}
let mut agent = sess.agent()?;
if agent.connect().is_err() {
// If the agent is around, we can proceed with other methods
return Ok(false);
}
agent.list_identities()?;
let identities = agent.identities()?;
for identity in identities {
if agent.userauth(user, &identity).is_ok() {
return Ok(true);
}
}
Ok(false)
}
#[cfg(feature = "ssh2")]
fn pubkey_auth(
&mut self,
sess: &ssh2::Session,
user: &str,
host: &str,
) -> anyhow::Result<bool> {
use std::path::{Path, PathBuf};
if let Some(files) = self.config.get("identityfile") {
for file in files.split_whitespace() {
let pubkey: PathBuf = format!("{}.pub", file).into();
let file = Path::new(file);
if !file.exists() {
continue;
}
let pubkey = if pubkey.exists() {
Some(pubkey.as_ref())
} else {
None
};
// We try with no passphrase first, in case the key is unencrypted
match sess.userauth_pubkey_file(user, pubkey, &file, None) {
Ok(_) => {
log::info!("pubkey_file immediately ok for {}", file.display());
return Ok(true);
}
Err(_) => {
// Most likely cause of error is that we need a passphrase
// to decrypt the key, so let's prompt the user for one.
let (reply, answers) = bounded(1);
self.tx_event
.try_send(SessionEvent::Authenticate(AuthenticationEvent {
username: "".to_string(),
instructions: "".to_string(),
prompts: vec![AuthenticationPrompt {
prompt: format!(
"Passphrase to decrypt {} for {}@{}:\n> ",
file.display(),
user,
host
),
echo: false,
}],
reply,
}))
.context("sending Authenticate request to user")?;
let answers = smol::block_on(answers.recv())
.context("waiting for authentication answers from user")?;
if answers.is_empty() {
anyhow::bail!("user cancelled authentication");
}
let passphrase = &answers[0];
match sess.userauth_pubkey_file(user, pubkey, &file, Some(passphrase)) {
Ok(_) => {
return Ok(true);
}
Err(err) => {
log::warn!("pubkey auth: {:#}", err);
}
}
}
}
}
}
Ok(false)
}
#[cfg(feature = "libssh-rs")]
pub fn authenticate_libssh(&mut self, sess: &libssh_rs::Session) -> anyhow::Result<()> {
use std::collections::HashMap;
let tx = self.tx_event.clone();
// Set the callback for pubkey auth
sess.set_auth_callback(move |prompt, echo, _verify, identity| {
let (reply, answers) = bounded(1);
tx.try_send(SessionEvent::Authenticate(AuthenticationEvent {
username: "".to_string(),
instructions: "".to_string(),
prompts: vec![AuthenticationPrompt {
prompt: match identity {
Some(ident) => format!("{} ({}): ", prompt, ident),
None => prompt.to_string(),
},
echo,
}],
reply,
}))
.unwrap();
let mut answers = smol::block_on(answers.recv())
.context("waiting for authentication answers from user")
.unwrap();
Ok(answers.remove(0))
});
use libssh_rs::{AuthMethods, AuthStatus};
match sess.userauth_none(None)? {
AuthStatus::Success => return Ok(()),
_ => {}
}
loop {
let auth_methods = sess.userauth_list(None)?;
let mut status_by_method = HashMap::new();
if auth_methods.contains(AuthMethods::PUBLIC_KEY) {
match sess.userauth_public_key_auto(None, None)? {
AuthStatus::Success => return Ok(()),
AuthStatus::Partial => continue,
status => {
status_by_method.insert(AuthMethods::PUBLIC_KEY, status);
}
}
}
if auth_methods.contains(AuthMethods::INTERACTIVE) {
loop {
match sess.userauth_keyboard_interactive(None, None)? {
AuthStatus::Success => return Ok(()),
AuthStatus::Info => {
let info = sess.userauth_keyboard_interactive_info()?;
let (reply, answers) = bounded(1);
self.tx_event
.try_send(SessionEvent::Authenticate(AuthenticationEvent {
username: sess.get_user_name()?,
instructions: info.instruction,
prompts: info
.prompts
.into_iter()
.map(|p| AuthenticationPrompt {
prompt: p.prompt,
echo: p.echo,
})
.collect(),
reply,
}))
.context("sending Authenticate request to user")?;
let answers = smol::block_on(answers.recv())
.context("waiting for authentication answers from user")?;
sess.userauth_keyboard_interactive_set_answers(&answers)?;
continue;
}
AuthStatus::Denied => {
break;
}
AuthStatus::Partial => continue,
status => {
anyhow::bail!("interactive auth status: {:?}", status);
}
}
}
}
if auth_methods.contains(AuthMethods::PASSWORD) {
let (reply, answers) = bounded(1);
self.tx_event
.try_send(SessionEvent::Authenticate(AuthenticationEvent {
username: "".to_string(),
instructions: "".to_string(),
prompts: vec![AuthenticationPrompt {
prompt: "Password: ".to_string(),
echo: false,
}],
reply,
}))
.unwrap();
let mut answers = smol::block_on(answers.recv())
.context("waiting for authentication answers from user")
.unwrap();
let pw = answers.remove(0);
match sess.userauth_password(None, Some(&pw))? {
AuthStatus::Success => return Ok(()),
AuthStatus::Partial => continue,
status => anyhow::bail!("password auth status: {:?}", status),
}
}
anyhow::bail!(
"unhandled auth case; methods={:?}, status={:?}",
auth_methods,
status_by_method
);
}
}
#[cfg(feature = "ssh2")]
pub fn authenticate(
&mut self,
sess: &ssh2::Session,
user: &str,
host: &str,
) -> anyhow::Result<()> {
use std::collections::HashSet;
loop {
if sess.authenticated() {
return Ok(());
}
// Re-query the auth methods on each loop as a successful method
// may unlock a new method on a subsequent iteration (eg: password
// auth may then unlock 2fac)
let methods: HashSet<&str> = sess.auth_methods(&user)?.split(',').collect();
log::trace!("ssh auth methods: {:?}", methods);
if !sess.authenticated() && methods.contains("publickey") {
if self.agent_auth(sess, user)? {
continue;
}
if self.pubkey_auth(sess, user, host)? {
continue;
}
}
if !sess.authenticated() && methods.contains("password") {
let (reply, answers) = bounded(1);
self.tx_event
.try_send(SessionEvent::Authenticate(AuthenticationEvent {
username: user.to_string(),
instructions: "".to_string(),
prompts: vec![AuthenticationPrompt {
prompt: format!("Password for {}@{}: ", user, host),
echo: false,
}],
reply,
}))
.context("sending Authenticate request to user")?;
let answers = smol::block_on(answers.recv())
.context("waiting for authentication answers from user")?;
if answers.is_empty() {
anyhow::bail!("user cancelled authentication");
}
if let Err(err) = sess.userauth_password(user, &answers[0]) {
log::error!("while attempting password auth: {}", err);
}
}
if !sess.authenticated() && methods.contains("keyboard-interactive") {
struct Helper<'a> {
tx_event: &'a Sender<SessionEvent>,
}
impl<'a> ssh2::KeyboardInteractivePrompt for Helper<'a> {
fn prompt<'b>(
&mut self,
username: &str,
instructions: &str,
prompts: &[ssh2::Prompt<'b>],
) -> Vec<String> {
let (reply, answers) = bounded(1);
if let Err(err) = self.tx_event.try_send(SessionEvent::Authenticate(
AuthenticationEvent {
username: username.to_string(),
instructions: instructions.to_string(),
prompts: prompts
.iter()
.map(|p| AuthenticationPrompt {
prompt: p.text.to_string(),
echo: p.echo,
})
.collect(),
reply,
},
)) {
log::error!("sending Authenticate request to user: {:#}", err);
return vec![];
}
match smol::block_on(answers.recv()) {
Err(err) => {
log::error!(
"waiting for authentication answers from user: {:#}",
err
);
return vec![];
}
Ok(answers) => answers,
}
}
}
let mut helper = Helper {
tx_event: &self.tx_event,
};
if let Err(err) = sess.userauth_keyboard_interactive(user, &mut helper) {
log::error!("while attempting keyboard-interactive auth: {}", err);
}
}
}
}
}