Debug the Dovecot Auth Protocol #95

Merged
quentin merged 3 commits from bug/dovecot-auth-resp into main 2024-02-13 16:13:53 +00:00
2 changed files with 57 additions and 52 deletions
Showing only changes of commit 25e716a17f - Show all commits

View file

@ -203,6 +203,39 @@ enum State {
const SERVER_MAJOR: u64 = 1;
const SERVER_MINOR: u64 = 2;
impl State {
async fn try_auth_plain<'a>(&self, data: &'a [u8], login: &ArcLoginProvider) -> AuthRes {
// Check that we can extract user's login+pass
let (ubin, pbin) = match auth_plain(&data) {
Ok(([], ([], user, pass))) => (user, pass),
Ok(_) => {
tracing::error!("Impersonating user is not supported");
return AuthRes::Failed(None, None);
}
Err(e) => {
tracing::error!(err=?e, "Could not parse the SASL PLAIN data chunk");
return AuthRes::Failed(None, None);
}
};
// Try to convert it to UTF-8
let (user, password) = match (std::str::from_utf8(ubin), std::str::from_utf8(pbin)) {
(Ok(u), Ok(p)) => (u, p),
_ => {
tracing::error!("Username or password contain invalid UTF-8 characters");
return AuthRes::Failed(None, None);
}
};
// Try to connect user
match login.login(user, password).await {
Ok(_) => AuthRes::Success(user.to_string()),
Err(e) => {
tracing::warn!(err=?e, "login failed");
AuthRes::Failed(Some(user.to_string()), None)
}
}
}
async fn progress(&mut self, cmd: ClientCommand, login: &ArcLoginProvider) {
let new_state = 'state: {
match (std::mem::replace(self, State::Error), cmd) {
@ -219,8 +252,18 @@ impl State {
Self::HandshakeDone
}
(Self::HandshakeDone { .. }, ClientCommand::Auth { id, mech, .. })
| (Self::AuthDone { .. }, ClientCommand::Auth { id, mech, .. }) => {
(
Self::HandshakeDone { .. },
ClientCommand::Auth {
id, mech, options, ..
},
)
| (
Self::AuthDone { .. },
ClientCommand::Auth {
id, mech, options, ..
},
) => {
if mech != Mechanism::Plain {
tracing::error!(mechanism=?mech, "Unsupported Authentication Mechanism");
break 'state Self::AuthDone {
@ -229,7 +272,13 @@ impl State {
};
}
Self::AuthPlainProgress { id }
match options.last() {
Some(AuthOption::Resp(data)) => Self::AuthDone {
id,
res: self.try_auth_plain(&data, login).await,
},
_ => Self::AuthPlainProgress { id },
}
}
(Self::AuthPlainProgress { id }, ClientCommand::Cont { id: cid, data }) => {
// Check that ID matches
@ -245,53 +294,9 @@ impl State {
};
}
// Check that we can extract user's login+pass
let (ubin, pbin) = match auth_plain(&data) {
Ok(([], ([], user, pass))) => (user, pass),
Ok(_) => {
tracing::error!("Impersonating user is not supported");
break 'state Self::AuthDone {
id,
res: AuthRes::Failed(None, None),
};
}
Err(e) => {
tracing::error!(err=?e, "Could not parse the SASL PLAIN data chunk");
break 'state Self::AuthDone {
id,
res: AuthRes::Failed(None, None),
};
}
};
// Try to convert it to UTF-8
let (user, password) =
match (std::str::from_utf8(ubin), std::str::from_utf8(pbin)) {
(Ok(u), Ok(p)) => (u, p),
_ => {
tracing::error!(
"Username or password contain invalid UTF-8 characters"
);
break 'state Self::AuthDone {
id,
res: AuthRes::Failed(None, None),
};
}
};
// Try to connect user
match login.login(user, password).await {
Ok(_) => Self::AuthDone {
id,
res: AuthRes::Success(user.to_string()),
},
Err(e) => {
tracing::warn!(err=?e, "login failed");
Self::AuthDone {
id,
res: AuthRes::Failed(Some(user.to_string()), None),
}
}
Self::AuthDone {
id,
res: self.try_auth_plain(&data, login).await,
}
}
_ => {

View file

@ -16,7 +16,7 @@ use tokio::select;
use tokio::sync::watch;
use tokio_util::compat::*;
use smtp_message::{Email, EscapedDataReader, DataUnescaper, Reply, ReplyCode};
use smtp_message::{DataUnescaper, Email, EscapedDataReader, Reply, ReplyCode};
use smtp_server::{reply, Config, ConnectionMetadata, Decision, MailMetadata};
use crate::config::*;
@ -186,7 +186,7 @@ impl Config for LmtpServer {
// Unescape email, shrink it also to remove last dot
let unesc_res = DataUnescaper::new(true).unescape(&mut text);
text.truncate(unesc_res.written);
tracing::debug!(prev_sz=raw_size, new_sz=text.len(), "unescaped");
tracing::debug!(prev_sz = raw_size, new_sz = text.len(), "unescaped");
let encrypted_message = match EncryptedMessage::new(text) {
Ok(x) => Arc::new(x),