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/*
* SPDX-FileCopyrightText: 2020 Stalwart Labs Ltd <hello@stalw.art>
*
* SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-SEL
*/
use common::{
config::server::ServerProtocol, listener::SessionStream, AuthFailureReason, AuthResult,
};
use imap_proto::{
protocol::{authenticate::Mechanism, capability::Capability},
receiver::{self, Request},
Command, ResponseCode, StatusResponse,
};
use mail_parser::decoders::base64::base64_decode;
use mail_send::Credentials;
use std::sync::Arc;
use crate::core::{Session, SessionData, State};
impl<T: SessionStream> Session<T> {
pub async fn handle_authenticate(&mut self, request: Request<Command>) -> crate::OpResult {
match request.parse_authenticate() {
Ok(mut args) => match args.mechanism {
Mechanism::Plain | Mechanism::OAuthBearer => {
if !args.params.is_empty() {
match base64_decode(args.params.pop().unwrap().as_bytes()) {
Some(challenge) => {
let result = if args.mechanism == Mechanism::Plain {
decode_challenge_plain(&challenge)
} else {
decode_challenge_oauth(&challenge)
};
match result {
Ok(credentials) => {
self.authenticate(credentials, args.tag).await
}
Err(err) => {
self.write_bytes(
StatusResponse::no(err).with_tag(args.tag).into_bytes(),
)
.await
}
}
}
None => {
self.write_bytes(
StatusResponse::no("Failed to decode challenge.")
.with_tag(args.tag)
.with_code(ResponseCode::Parse)
.into_bytes(),
)
.await
}
}
} else {
self.receiver.request = receiver::Request {
tag: args.tag,
command: Command::Authenticate,
tokens: vec![receiver::Token::Argument(args.mechanism.into_bytes())],
};
self.receiver.state = receiver::State::Argument { last_ch: b' ' };
self.write_bytes(b"+ \"\"\r\n".to_vec()).await
}
}
_ => {
self.write_bytes(
StatusResponse::no("Authentication mechanism not supported.")
.with_tag(args.tag)
.with_code(ResponseCode::Cannot)
.into_bytes(),
)
.await
}
},
Err(response) => self.write_bytes(response.into_bytes()).await,
}
}
pub async fn authenticate(
&mut self,
credentials: Credentials<String>,
tag: String,
) -> crate::Result<()> {
// Throttle authentication requests
if self
.jmap
.is_auth_allowed_soft(&self.remote_addr)
.await
.is_err()
{
self.write_bytes(
StatusResponse::bye("Too many authentication requests from this IP address.")
.into_bytes(),
)
.await?;
tracing::debug!(parent: &self.span,
event = "disconnect",
"Too many authentication attempts, disconnecting.",
);
return Err(());
}
// Authenticate
let mut is_totp_error = false;
let access_token = match credentials {
Credentials::Plain { username, secret } | Credentials::XOauth2 { username, secret } => {
match self
.jmap
.authenticate_plain(&username, &secret, self.remote_addr, ServerProtocol::Imap)
.await
{
AuthResult::Success(token) => Some(token),
AuthResult::Failure(
AuthFailureReason::InvalidCredentials | AuthFailureReason::InternalError(_),
) => None,
AuthResult::Failure(AuthFailureReason::MissingTotp) => {
is_totp_error = true;
None
}
AuthResult::Failure(AuthFailureReason::Banned) => return Err(()),
}
}
Credentials::OAuthBearer { token } => {
match self
.jmap
.validate_access_token("access_token", &token)
.await
{
Ok((account_id, _, _)) => self.jmap.get_access_token(account_id).await,
Err(err) => {
tracing::debug!(
parent: &self.span,
context = "authenticate",
err = err,
"Failed to validate access token."
);
None
}
}
}
};
if let Some(access_token) = access_token {
// Enforce concurrency limits
let in_flight = match self
.get_concurrency_limiter(access_token.primary_id())
.map(|limiter| limiter.concurrent_requests.is_allowed())
{
Some(Some(limiter)) => Some(limiter),
None => None,
Some(None) => {
self.write_bytes(
StatusResponse::bye("Too many concurrent IMAP connections.").into_bytes(),
)
.await?;
tracing::debug!(parent: &self.span,
event = "disconnect",
"Too many concurrent connections, disconnecting.",
);
return Err(());
}
};
// Cache access token
let access_token = Arc::new(access_token);
self.jmap.cache_access_token(access_token.clone());
// Create session
self.state = State::Authenticated {
data: Arc::new(SessionData::new(self, &access_token, in_flight).await?),
};
self.write_bytes(
StatusResponse::ok("Authentication successful")
.with_code(ResponseCode::Capability {
capabilities: Capability::all_capabilities(true, self.is_tls),
})
.with_tag(tag)
.into_bytes(),
)
.await?;
Ok(())
} else {
self.write_bytes(
StatusResponse::no(if is_totp_error {
"Missing TOTP code, try with 'secret$totp_code'."
} else {
"Authentication failed."
})
.with_tag(tag)
.with_code(ResponseCode::AuthenticationFailed)
.into_bytes(),
)
.await?;
let auth_failures = self.state.auth_failures();
if auth_failures < self.jmap.core.imap.max_auth_failures {
self.state = State::NotAuthenticated {
auth_failures: auth_failures + 1,
};
Ok(())
} else {
self.write_bytes(
StatusResponse::bye("Too many authentication failures").into_bytes(),
)
.await?;
tracing::debug!(
parent: &self.span,
event = "disconnect",
"Too many authentication failures, disconnecting.",
);
Err(())
}
}
}
pub async fn handle_unauthenticate(&mut self, request: Request<Command>) -> crate::OpResult {
self.state = State::NotAuthenticated { auth_failures: 0 };
self.write_bytes(
StatusResponse::completed(Command::Unauthenticate)
.with_tag(request.tag)
.into_bytes(),
)
.await
}
}
pub fn decode_challenge_plain(challenge: &[u8]) -> Result<Credentials<String>, &'static str> {
let mut username = Vec::new();
let mut secret = Vec::new();
let mut arg_num = 0;
for &ch in challenge {
if ch != 0 {
match arg_num.cmp(&2) {
std::cmp::Ordering::Less => {
username.push(ch);
}
std::cmp::Ordering::Equal => {
secret.push(ch);
}
std::cmp::Ordering::Greater => (),
}
} else {
arg_num += 1;
}
}
match (String::from_utf8(username), String::from_utf8(secret)) {
(Ok(username), Ok(secret)) if !username.is_empty() && !secret.is_empty() => {
Ok((username, secret).into())
}
_ => Err("Invalid AUTH=PLAIN challenge."),
}
}
pub fn decode_challenge_oauth(challenge: &[u8]) -> Result<Credentials<String>, &'static str> {
let mut saw_marker = true;
for (pos, &ch) in challenge.iter().enumerate() {
if saw_marker {
if challenge
.get(pos..)
.map_or(false, |b| b.starts_with(b"auth=Bearer "))
{
let pos = pos + 12;
return Ok(Credentials::OAuthBearer {
token: String::from_utf8(
challenge
.get(
pos..pos
+ challenge
.get(pos..)
.and_then(|c| c.iter().position(|&ch| ch == 0x01))
.unwrap_or(challenge.len()),
)
.ok_or("Failed to find end of bearer token")?
.to_vec(),
)
.map_err(|_| "Bearer token is not a valid UTF-8 string.")?,
});
} else {
saw_marker = false;
}
} else if ch == 0x01 {
saw_marker = true;
}
}
Err("Failed to find 'auth=Bearer' in challenge.")
}
|
