use crate::enums::ProtocolVersion;
use crate::error::{Error, PeerMisbehaved};
use crate::key;
#[cfg(feature = "logging")]
use crate::log::{debug, error, trace, warn};
use crate::msgs::alert::AlertMessagePayload;
use crate::msgs::base::Payload;
use crate::msgs::deframer::{Deframed, MessageDeframer};
use crate::msgs::enums::HandshakeType;
use crate::msgs::enums::{AlertDescription, AlertLevel, ContentType};
use crate::msgs::fragmenter::MessageFragmenter;
use crate::msgs::handshake::Random;
use crate::msgs::message::{
BorrowedPlainMessage, Message, MessagePayload, OpaqueMessage, PlainMessage,
};
#[cfg(feature = "quic")]
use crate::quic;
use crate::record_layer;
use crate::suites::SupportedCipherSuite;
#[cfg(feature = "secret_extraction")]
use crate::suites::{ExtractedSecrets, PartiallyExtractedSecrets};
#[cfg(feature = "tls12")]
use crate::tls12::ConnectionSecrets;
use crate::vecbuf::ChunkVecBuffer;
#[cfg(feature = "quic")]
use std::collections::VecDeque;
use std::fmt::Debug;
use std::io;
use std::mem;
use std::ops::{Deref, DerefMut};
/// A client or server connection.
#[derive(Debug)]
pub enum Connection {
/// A client connection
Client(crate::client::ClientConnection),
/// A server connection
Server(crate::server::ServerConnection),
}
impl Connection {
/// Read TLS content from `rd`.
///
/// See [`ConnectionCommon::read_tls()`] for more information.
pub fn read_tls(&mut self, rd: &mut dyn io::Read) -> Result<usize, io::Error> {
match self {
Self::Client(conn) => conn.read_tls(rd),
Self::Server(conn) => conn.read_tls(rd),
}
}
/// Returns an object that allows reading plaintext.
pub fn reader(&mut self) -> Reader {
match self {
Self::Client(conn) => conn.reader(),
Self::Server(conn) => conn.reader(),
}
}
/// Returns an object that allows writing plaintext.
pub fn writer(&mut self) -> Writer {
match self {
Self::Client(conn) => Writer::new(&mut **conn),
Self::Server(conn) => Writer::new(&mut **conn),
}
}
/// Processes any new packets read by a previous call to [`Connection::read_tls`].
///
/// See [`ConnectionCommon::process_new_packets()`] for more information.
pub fn process_new_packets(&mut self) -> Result<IoState, Error> {
match self {
Self::Client(conn) => conn.process_new_packets(),
Self::Server(conn) => conn.process_new_packets(),
}
}
/// Derives key material from the agreed connection secrets.
///
/// See [`ConnectionCommon::export_keying_material()`] for more information.
pub fn export_keying_material(
&self,
output: &mut [u8],
label: &[u8],
context: Option<&[u8]>,
) -> Result<(), Error> {
match self {
Self::Client(conn) => conn.export_keying_material(output, label, context),
Self::Server(conn) => conn.export_keying_material(output, label, context),
}
}
/// Extract secrets, to set up kTLS for example
#[cfg(feature = "secret_extraction")]
pub fn extract_secrets(self) -> Result<ExtractedSecrets, Error> {
match self {
Self::Client(conn) => conn.extract_secrets(),
Self::Server(conn) => conn.extract_secrets(),
}
}
/// This function uses `io` to complete any outstanding IO for this connection.
///
/// See [`ConnectionCommon::complete_io()`] for more information.
pub fn complete_io<T>(&mut self, io: &mut T) -> Result<(usize, usize), io::Error>
where
Self: Sized,
T: io::Read + io::Write,
{
match self {
Self::Client(conn) => conn.complete_io(io),
Self::Server(conn) => conn.complete_io(io),
}
}
}
#[cfg(feature = "quic")]
impl crate::quic::QuicExt for Connection {
fn quic_transport_parameters(&self) -> Option<&[u8]> {
match self {
Self::Client(conn) => conn.quic_transport_parameters(),
Self::Server(conn) => conn.quic_transport_parameters(),
}
}
fn zero_rtt_keys(&self) -> Option<quic::DirectionalKeys> {
match self {
Self::Client(conn) => conn.zero_rtt_keys(),
Self::Server(conn) => conn.zero_rtt_keys(),
}
}
fn read_hs(&mut self, plaintext: &[u8]) -> Result<(), Error> {
match self {
Self::Client(conn) => conn.read_quic_hs(plaintext),
Self::Server(conn) => conn.read_quic_hs(plaintext),
}
}
fn write_hs(&mut self, buf: &mut Vec<u8>) -> Option<quic::KeyChange> {
match self {
Self::Client(conn) => quic::write_hs(conn, buf),
Self::Server(conn) => quic::write_hs(conn, buf),
}
}
fn alert(&self) -> Option<AlertDescription> {
match self {
Self::Client(conn) => conn.alert(),
Self::Server(conn) => conn.alert(),
}
}
}
impl Deref for Connection {
type Target = CommonState;
fn deref(&self) -> &Self::Target {
match self {
Self::Client(conn) => &conn.common_state,
Self::Server(conn) => &conn.common_state,
}
}
}
impl DerefMut for Connection {
fn deref_mut(&mut self) -> &mut Self::Target {
match self {
Self::Client(conn) => &mut conn.common_state,
Self::Server(conn) => &mut conn.common_state,
}
}
}
/// Values of this structure are returned from [`Connection::process_new_packets`]
/// and tell the caller the current I/O state of the TLS connection.
#[derive(Debug, Eq, PartialEq)]
pub struct IoState {
tls_bytes_to_write: usize,
plaintext_bytes_to_read: usize,
peer_has_closed: bool,
}
impl IoState {
/// How many bytes could be written by [`CommonState::write_tls`] if called
/// right now. A non-zero value implies [`CommonState::wants_write`].
pub fn tls_bytes_to_write(&self) -> usize {
self.tls_bytes_to_write
}
/// How many plaintext bytes could be obtained via [`std::io::Read`]
/// without further I/O.
pub fn plaintext_bytes_to_read(&self) -> usize {
self.plaintext_bytes_to_read
}
/// True if the peer has sent us a close_notify alert. This is
/// the TLS mechanism to securely half-close a TLS connection,
/// and signifies that the peer will not send any further data
/// on this connection.
///
/// This is also signalled via returning `Ok(0)` from
/// [`std::io::Read`], after all the received bytes have been
/// retrieved.
pub fn peer_has_closed(&self) -> bool {
self.peer_has_closed
}
}
/// A structure that implements [`std::io::Read`] for reading plaintext.
pub struct Reader<'a> {
received_plaintext: &'a mut ChunkVecBuffer,
peer_cleanly_closed: bool,
has_seen_eof: bool,
}
impl<'a> io::Read for Reader<'a> {
/// Obtain plaintext data received from the peer over this TLS connection.
///
/// If the peer closes the TLS session cleanly, this returns `Ok(0)` once all
/// the pending data has been read. No further data can be received on that
/// connection, so the underlying TCP connection should be half-closed too.
///
/// If the peer closes the TLS session uncleanly (a TCP EOF without sending a
/// `close_notify` alert) this function returns `Err(ErrorKind::UnexpectedEof.into())`
/// once any pending data has been read.
///
/// Note that support for `close_notify` varies in peer TLS libraries: many do not
/// support it and uncleanly close the TCP connection (this might be
/// vulnerable to truncation attacks depending on the application protocol).
/// This means applications using rustls must both handle EOF
/// from this function, *and* unexpected EOF of the underlying TCP connection.
///
/// If there are no bytes to read, this returns `Err(ErrorKind::WouldBlock.into())`.
///
/// You may learn the number of bytes available at any time by inspecting
/// the return of [`Connection::process_new_packets`].
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
let len = self.received_plaintext.read(buf)?;
if len == 0 && !buf.is_empty() {
// No bytes available:
match (self.peer_cleanly_closed, self.has_seen_eof) {
// cleanly closed; don't care about TCP EOF: express this as Ok(0)
(true, _) => {}
// unclean closure
(false, true) => return Err(io::ErrorKind::UnexpectedEof.into()),
// connection still going, but need more data: signal `WouldBlock` so that
// the caller knows this
(false, false) => return Err(io::ErrorKind::WouldBlock.into()),
}
}
Ok(len)
}
/// Obtain plaintext data received from the peer over this TLS connection.
///
/// If the peer closes the TLS session, this returns `Ok(())` without filling
/// any more of the buffer once all the pending data has been read. No further
/// data can be received on that connection, so the underlying TCP connection
/// should be half-closed too.
///
/// If the peer closes the TLS session uncleanly (a TCP EOF without sending a
/// `close_notify` alert) this function returns `Err(ErrorKind::UnexpectedEof.into())`
/// once any pending data has been read.
///
/// Note that support for `close_notify` varies in peer TLS libraries: many do not
/// support it and uncleanly close the TCP connection (this might be
/// vulnerable to truncation attacks depending on the application protocol).
/// This means applications using rustls must both handle EOF
/// from this function, *and* unexpected EOF of the underlying TCP connection.
///
/// If there are no bytes to read, this returns `Err(ErrorKind::WouldBlock.into())`.
///
/// You may learn the number of bytes available at any time by inspecting
/// the return of [`Connection::process_new_packets`].
#[cfg(read_buf)]
fn read_buf(&mut self, mut cursor: io::BorrowedCursor<'_>) -> io::Result<()> {
let before = cursor.written();
self.received_plaintext
.read_buf(cursor.reborrow())?;
let len = cursor.written() - before;
if len == 0 && cursor.capacity() > 0 {
// No bytes available:
match (self.peer_cleanly_closed, self.has_seen_eof) {
// cleanly closed; don't care about TCP EOF: express this as Ok(0)
(true, _) => {}
// unclean closure
(false, true) => return Err(io::ErrorKind::UnexpectedEof.into()),
// connection still going, but need more data: signal `WouldBlock` so that
// the caller knows this
(false, false) => return Err(io::ErrorKind::WouldBlock.into()),
}
}
Ok(())
}
}
/// Internal trait implemented by the [`ServerConnection`]/[`ClientConnection`]
/// allowing them to be the subject of a [`Writer`].
pub(crate) trait PlaintextSink {
fn write(&mut self, buf: &[u8]) -> io::Result<usize>;
fn write_vectored(&mut self, bufs: &[io::IoSlice<'_>]) -> io::Result<usize>;
fn flush(&mut self) -> io::Result<()>;
}
impl<T> PlaintextSink for ConnectionCommon<T> {
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
Ok(self.send_some_plaintext(buf))
}
fn write_vectored(&mut self, bufs: &[io::IoSlice<'_>]) -> io::Result<usize> {
let mut sz = 0;
for buf in bufs {
sz += self.send_some_plaintext(buf);
}
Ok(sz)
}
fn flush(&mut self) -> io::Result<()> {
Ok(())
}
}
/// A structure that implements [`std::io::Write`] for writing plaintext.
pub struct Writer<'a> {
sink: &'a mut dyn PlaintextSink,
}
impl<'a> Writer<'a> {
/// Create a new Writer.
///
/// This is not an external interface. Get one of these objects
/// from [`Connection::writer`].
pub(crate) fn new(sink: &'a mut dyn PlaintextSink) -> Writer<'a> {
Writer { sink }
}
}
impl<'a> io::Write for Writer<'a> {
/// Send the plaintext `buf` to the peer, encrypting
/// and authenticating it. Once this function succeeds
/// you should call [`CommonState::write_tls`] which will output the
/// corresponding TLS records.
///
/// This function buffers plaintext sent before the
/// TLS handshake completes, and sends it as soon
/// as it can. See [`CommonState::set_buffer_limit`] to control
/// the size of this buffer.
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
self.sink.write(buf)
}
fn write_vectored(&mut self, bufs: &[io::IoSlice<'_>]) -> io::Result<usize> {
self.sink.write_vectored(bufs)
}
fn flush(&mut self) -> io::Result<()> {
self.sink.flush()
}
}
#[derive(Copy, Clone, Eq, PartialEq, Debug)]
pub(crate) enum Protocol {
Tcp,
#[cfg(feature = "quic")]
Quic,
}
#[derive(Debug)]
pub(crate) struct ConnectionRandoms {
pub(crate) client: [u8; 32],
pub(crate) server: [u8; 32],
}
/// How many ChangeCipherSpec messages we accept and drop in TLS1.3 handshakes.
/// The spec says 1, but implementations (namely the boringssl test suite) get
/// this wrong. BoringSSL itself accepts up to 32.
static TLS13_MAX_DROPPED_CCS: u8 = 2u8;
impl ConnectionRandoms {
pub(crate) fn new(client: Random, server: Random) -> Self {
Self {
client: client.0,
server: server.0,
}
}
}
// --- Common (to client and server) connection functions ---
fn is_valid_ccs(msg: &PlainMessage) -> bool {
// We passthrough ChangeCipherSpec messages in the deframer without decrypting them.
// nb. this is prior to the record layer, so is unencrypted. see
// third paragraph of section 5 in RFC8446.
msg.typ == ContentType::ChangeCipherSpec && msg.payload.0 == [0x01]
}
enum Limit {
Yes,
No,
}
/// Interface shared by client and server connections.
pub struct ConnectionCommon<Data> {
state: Result<Box<dyn State<Data>>, Error>,
pub(crate) data: Data,
pub(crate) common_state: CommonState,
message_deframer: MessageDeframer,
}
impl<Data> ConnectionCommon<Data> {
pub(crate) fn new(state: Box<dyn State<Data>>, data: Data, common_state: CommonState) -> Self {
Self {
state: Ok(state),
data,
common_state,
message_deframer: MessageDeframer::default(),
}
}
/// Returns an object that allows reading plaintext.
pub fn reader(&mut self) -> Reader {
Reader {
received_plaintext: &mut self.common_state.received_plaintext,
/// Are we done? i.e., have we processed all received messages, and received a
/// close_notify to indicate that no new messages will arrive?
peer_cleanly_closed: self
.common_state
.has_received_close_notify
&& !self.message_deframer.has_pending(),
has_seen_eof: self.common_state.has_seen_eof,
}
}
/// Returns an object that allows writing plaintext.
pub fn writer(&mut self) -> Writer {
Writer::new(self)
}
/// This function uses `io` to complete any outstanding IO for
/// this connection.
///
/// This is a convenience function which solely uses other parts
/// of the public API.
///
/// What this means depends on the connection state:
///
/// - If the connection [`is_handshaking`], then IO is performed until
/// the handshake is complete.
/// - Otherwise, if [`wants_write`] is true, [`write_tls`] is invoked
/// until it is all written.
/// - Otherwise, if [`wants_read`] is true, [`read_tls`] is invoked
/// once.
///
/// The return value is the number of bytes read from and written
/// to `io`, respectively.
///
/// This function will block if `io` blocks.
///
/// Errors from TLS record handling (i.e., from [`process_new_packets`])
/// are wrapped in an `io::ErrorKind::InvalidData`-kind error.
///
/// [`is_handshaking`]: CommonState::is_handshaking
/// [`wants_read`]: CommonState::wants_read
/// [`wants_write`]: CommonState::wants_write
/// [`write_tls`]: CommonState::write_tls
/// [`read_tls`]: ConnectionCommon::read_tls
/// [`process_new_packets`]: ConnectionCommon::process_new_packets
pub fn complete_io<T>(&mut self, io: &mut T) -> Result<(usize, usize), io::Error>
where
Self: Sized,
T: io::Read + io::Write,
{
let until_handshaked = self.is_handshaking();
let mut eof = false;
let mut wrlen = 0;
let mut rdlen = 0;
loop {
while self.wants_write() {
wrlen += self.write_tls(io)?;
}
if !until_handshaked && wrlen > 0 {
return Ok((rdlen, wrlen));
}
while !eof && self.wants_read() {
let read_size = match self.read_tls(io) {
Ok(0) => {
eof = true;
Some(0)
}
Ok(n) => {
rdlen += n;
Some(n)
}
Err(ref err) if err.kind() == io::ErrorKind::Interrupted => None, // nothing to do
Err(err) => return Err(err),
};
if read_size.is_some() {
break;
}
}
match self.process_new_packets() {
Ok(_) => {}
Err(e) => {
// In case we have an alert to send describing this error,
// try a last-gasp write -- but don't predate the primary
// error.
let _ignored = self.write_tls(io);
return Err(io::Error::new(io::ErrorKind::InvalidData, e));
}
};
match (eof, until_handshaked, self.is_handshaking()) {
(_, true, false) => return Ok((rdlen, wrlen)),
(_, false, _) => return Ok((rdlen, wrlen)),
(true, true, true) => return Err(io::Error::from(io::ErrorKind::UnexpectedEof)),
(..) => {}
}
}
}
/// Extract the first handshake message.
///
/// This is a shortcut to the `process_new_packets()` -> `process_msg()` ->
/// `process_handshake_messages()` path, specialized for the first handshake message.
pub(crate) fn first_handshake_message(&mut self) -> Result<Option<Message>, Error> {
match self.deframe()?.map(Message::try_from) {
Some(Ok(msg)) => Ok(Some(msg)),
Some(Err(err)) => {
self.common_state
.send_fatal_alert(AlertDescription::DecodeError);
Err(err)
}
None => Ok(None),
}
}
pub(crate) fn replace_state(&mut self, new: Box<dyn State<Data>>) {
self.state = Ok(new);
}
fn process_msg(
&mut self,
msg: PlainMessage,
state: Box<dyn State<Data>>,
) -> Result<Box<dyn State<Data>>, Error> {
// Drop CCS messages during handshake in TLS1.3
if msg.typ == ContentType::ChangeCipherSpec
&& !self
.common_state
.may_receive_application_data
&& self.common_state.is_tls13()
{
if !is_valid_ccs(&msg)
|| self.common_state.received_middlebox_ccs > TLS13_MAX_DROPPED_CCS
{
// "An implementation which receives any other change_cipher_spec value or
// which receives a protected change_cipher_spec record MUST abort the
// handshake with an "unexpected_message" alert."
self.common_state
.send_fatal_alert(AlertDescription::UnexpectedMessage);
return Err(Error::PeerMisbehaved(
PeerMisbehaved::IllegalMiddleboxChangeCipherSpec,
));
} else {
self.common_state.received_middlebox_ccs += 1;
trace!("Dropping CCS");
return Ok(state);
}
}
// Now we can fully parse the message payload.
let msg = match Message::try_from(msg) {
Ok(msg) => msg,
Err(err) => {
self.common_state
.send_fatal_alert(AlertDescription::DecodeError);
return Err(err);
}
};
// For alerts, we have separate logic.
if let MessagePayload::Alert(alert) = &msg.payload {
self.common_state.process_alert(alert)?;
return Ok(state);
}
self.common_state
.process_main_protocol(msg, state, &mut self.data)
}
/// Processes any new packets read by a previous call to
/// [`Connection::read_tls`].
///
/// Errors from this function relate to TLS protocol errors, and
/// are fatal to the connection. Future calls after an error will do
/// no new work and will return the same error. After an error is
/// received from [`process_new_packets`], you should not call [`read_tls`]
/// any more (it will fill up buffers to no purpose). However, you
/// may call the other methods on the connection, including `write`,
/// `send_close_notify`, and `write_tls`. Most likely you will want to
/// call `write_tls` to send any alerts queued by the error and then
/// close the underlying connection.
///
/// Success from this function comes with some sundry state data
/// about the connection.
///
/// [`read_tls`]: Connection::read_tls
/// [`process_new_packets`]: Connection::process_new_packets
pub fn process_new_packets(&mut self) -> Result<IoState, Error> {
let mut state = match mem::replace(&mut self.state, Err(Error::HandshakeNotComplete)) {
Ok(state) => state,
Err(e) => {
self.state = Err(e.clone());
return Err(e);
}
};
while let Some(msg) = self.deframe()? {
match self.process_msg(msg, state) {
Ok(new) => state = new,
Err(e) => {
self.state = Err(e.clone());
return Err(e);
}
}
}
self.state = Ok(state);
Ok(self.common_state.current_io_state())
}
/// Pull a message out of the deframer and send any messages that need to be sent as a result.
fn deframe(&mut self) -> Result<Option<PlainMessage>, Error> {
match self
.message_deframer
.pop(&mut self.common_state.record_layer)
{
Ok(Some(Deframed {
want_close_before_decrypt,
aligned,
trial_decryption_finished,
message,
})) => {
if want_close_before_decrypt {
self.common_state.send_close_notify();
}
if trial_decryption_finished {
self.common_state
.record_layer
.finish_trial_decryption();
}
self.common_state.aligned_handshake = aligned;
Ok(Some(message))
}
Ok(None) => Ok(None),
Err(err @ Error::CorruptMessage | err @ Error::CorruptMessagePayload(_)) => {
#[cfg(feature = "quic")]
if self.common_state.is_quic() {
self.common_state.quic.alert = Some(AlertDescription::DecodeError);
}
if !self.common_state.is_quic() {
self.common_state
.send_fatal_alert(AlertDescription::DecodeError);
}
Err(err)
}
Err(Error::PeerSentOversizedRecord) => {
self.common_state
.send_fatal_alert(AlertDescription::RecordOverflow);
Err(Error::PeerSentOversizedRecord)
}
Err(Error::DecryptError) => {
self.common_state
.send_fatal_alert(AlertDescription::BadRecordMac);
Err(Error::DecryptError)
}
Err(e) => Err(e),
}
}
pub(crate) fn send_some_plaintext(&mut self, buf: &[u8]) -> usize {
if let Ok(st) = &mut self.state {
st.perhaps_write_key_update(&mut self.common_state);
}
self.common_state
.send_some_plaintext(buf)
}
/// Read TLS content from `rd` into the internal buffer.
///
/// Due to the internal buffering, `rd` can supply TLS messages in arbitrary-sized chunks (like
/// a socket or pipe might).
///
/// You should call [`process_new_packets()`] each time a call to this function succeeds in order
/// to empty the incoming TLS data buffer.
///
/// This function returns `Ok(0)` when the underlying `rd` does so. This typically happens when
/// a socket is cleanly closed, or a file is at EOF. Errors may result from the IO done through
/// `rd`; additionally, errors of `ErrorKind::Other` are emitted to signal backpressure:
///
/// * In order to empty the incoming TLS data buffer, you should call [`process_new_packets()`]
/// each time a call to this function succeeds.
/// * In order to empty the incoming plaintext data buffer, you should empty it through
/// the [`reader()`] after the call to [`process_new_packets()`].
///
/// [`process_new_packets()`]: ConnectionCommon::process_new_packets
/// [`reader()`]: ConnectionCommon::reader
pub fn read_tls(&mut self, rd: &mut dyn io::Read) -> Result<usize, io::Error> {
if self.received_plaintext.is_full() {
return Err(io::Error::new(
io::ErrorKind::Other,
"received plaintext buffer full",
));
}
let res = self.message_deframer.read(rd);
if let Ok(0) = res {
self.common_state.has_seen_eof = true;
}
res
}
/// Derives key material from the agreed connection secrets.
///
/// This function fills in `output` with `output.len()` bytes of key
/// material derived from the master session secret using `label`
/// and `context` for diversification.
///
/// See RFC5705 for more details on what this does and is for.
///
/// For TLS1.3 connections, this function does not use the
/// "early" exporter at any point.
///
/// This function fails if called prior to the handshake completing;
/// check with [`CommonState::is_handshaking`] first.
pub fn export_keying_material(
&self,
output: &mut [u8],
label: &[u8],
context: Option<&[u8]>,
) -> Result<(), Error> {
match self.state.as_ref() {
Ok(st) => st.export_keying_material(output, label, context),
Err(e) => Err(e.clone()),
}
}
/// Extract secrets, so they can be used when configuring kTLS, for example.
#[cfg(feature = "secret_extraction")]
pub fn extract_secrets(self) -> Result<ExtractedSecrets, Error> {
if !self.enable_secret_extraction {
return Err(Error::General("Secret extraction is disabled".into()));
}
let st = self.state?;
let record_layer = self.common_state.record_layer;
let PartiallyExtractedSecrets { tx, rx } = st.extract_secrets()?;
Ok(ExtractedSecrets {
tx: (record_layer.write_seq(), tx),
rx: (record_layer.read_seq(), rx),
})
}
}
#[cfg(feature = "quic")]
impl<Data> ConnectionCommon<Data> {
pub(crate) fn read_quic_hs(&mut self, plaintext: &[u8]) -> Result<(), Error> {
self.message_deframer
.push(ProtocolVersion::TLSv1_3, plaintext)?;
self.process_new_packets()?;
Ok(())
}
}
impl<T> Deref for ConnectionCommon<T> {
type Target = CommonState;
fn deref(&self) -> &Self::Target {
&self.common_state
}
}
impl<T> DerefMut for ConnectionCommon<T> {
fn deref_mut(&mut self) -> &mut Self::Target {
&mut self.common_state
}
}
/// Connection state common to both client and server connections.
pub struct CommonState {
pub(crate) negotiated_version: Option<ProtocolVersion>,
pub(crate) side: Side,
pub(crate) record_layer: record_layer::RecordLayer,
pub(crate) suite: Option<SupportedCipherSuite>,
pub(crate) alpn_protocol: Option<Vec<u8>>,
aligned_handshake: bool,
pub(crate) may_send_application_data: bool,
pub(crate) may_receive_application_data: bool,
pub(crate) early_traffic: bool,
sent_fatal_alert: bool,
/// If the peer has signaled end of stream.
has_received_close_notify: bool,
has_seen_eof: bool,
received_middlebox_ccs: u8,
pub(crate) peer_certificates: Option<Vec<key::Certificate>>,
message_fragmenter: MessageFragmenter,
received_plaintext: ChunkVecBuffer,
sendable_plaintext: ChunkVecBuffer,
pub(crate) sendable_tls: ChunkVecBuffer,
#[allow(dead_code)] // only read for QUIC
/// Protocol whose key schedule should be used. Unused for TLS < 1.3.
pub(crate) protocol: Protocol,
#[cfg(feature = "quic")]
pub(crate) quic: Quic,
#[cfg(feature = "secret_extraction")]
pub(crate) enable_secret_extraction: bool,
}
impl CommonState {
pub(crate) fn new(side: Side) -> Self {
Self {
negotiated_version: None,
side,
record_layer: record_layer::RecordLayer::new(),
suite: None,
alpn_protocol: None,
aligned_handshake: true,
may_send_application_data: false,
may_receive_application_data: false,
early_traffic: false,
sent_fatal_alert: false,
has_received_close_notify: false,
has_seen_eof: false,
received_middlebox_ccs: 0,
peer_certificates: None,
message_fragmenter: MessageFragmenter::default(),
received_plaintext: ChunkVecBuffer::new(Some(DEFAULT_RECEIVED_PLAINTEXT_LIMIT)),
sendable_plaintext: ChunkVecBuffer::new(Some(DEFAULT_BUFFER_LIMIT)),
sendable_tls: ChunkVecBuffer::new(Some(DEFAULT_BUFFER_LIMIT)),
protocol: Protocol::Tcp,
#[cfg(feature = "quic")]
quic: Quic::new(),
#[cfg(feature = "secret_extraction")]
enable_secret_extraction: false,
}
}
/// Returns true if the caller should call [`CommonState::write_tls`] as soon
/// as possible.
pub fn wants_write(&self) -> bool {
!self.sendable_tls.is_empty()
}
/// Returns true if the connection is currently performing the TLS handshake.
///
/// During this time plaintext written to the connection is buffered in memory. After
/// [`Connection::process_new_packets`] has been called, this might start to return `false`
/// while the final handshake packets still need to be extracted from the connection's buffers.
pub fn is_handshaking(&self) -> bool {
!(self.may_send_application_data && self.may_receive_application_data)
}
/// Retrieves the certificate chain used by the peer to authenticate.
///
/// The order of the certificate chain is as it appears in the TLS
/// protocol: the first certificate relates to the peer, the
/// second certifies the first, the third certifies the second, and
/// so on.
///
/// This is made available for both full and resumed handshakes.
///
/// For clients, this is the certificate chain of the server.
///
/// For servers, this is the certificate chain of the client,
/// if client authentication was completed.
///
/// The return value is None until this value is available.
pub fn peer_certificates(&self) -> Option<&[key::Certificate]> {
self.peer_certificates.as_deref()
}
/// Retrieves the protocol agreed with the peer via ALPN.
///
/// A return value of `None` after handshake completion
/// means no protocol was agreed (because no protocols
/// were offered or accepted by the peer).
pub fn alpn_protocol(&self) -> Option<&[u8]> {
self.get_alpn_protocol()
}
/// Retrieves the ciphersuite agreed with the peer.
///
/// This returns None until the ciphersuite is agreed.
pub fn negotiated_cipher_suite(&self) -> Option<SupportedCipherSuite> {
self.suite
}
/// Retrieves the protocol version agreed with the peer.
///
/// This returns `None` until the version is agreed.
pub fn protocol_version(&self) -> Option<ProtocolVersion> {
self.negotiated_version
}
pub(crate) fn is_tls13(&self) -> bool {
matches!(self.negotiated_version, Some(ProtocolVersion::TLSv1_3))
}
fn process_main_protocol<Data>(
&mut self,
msg: Message,
mut state: Box<dyn State<Data>>,
data: &mut Data,
) -> Result<Box<dyn State<Data>>, Error> {
// For TLS1.2, outside of the handshake, send rejection alerts for
// renegotiation requests. These can occur any time.
if self.may_receive_application_data && !self.is_tls13() {
let reject_ty = match self.side {
Side::Client => HandshakeType::HelloRequest,
Side::Server => HandshakeType::ClientHello,
};
if msg.is_handshake_type(reject_ty) {
self.send_warning_alert(AlertDescription::NoRenegotiation);
return Ok(state);
}
}
let mut cx = Context { common: self, data };
match state.handle(&mut cx, msg) {
Ok(next) => {
state = next;
Ok(state)
}
Err(e @ Error::InappropriateMessage { .. })
| Err(e @ Error::InappropriateHandshakeMessage { .. }) => {
self.send_fatal_alert(AlertDescription::UnexpectedMessage);
Err(e)
}
Err(e) => Err(e),
}
}
/// Send plaintext application data, fragmenting and
/// encrypting it as it goes out.
///
/// If internal buffers are too small, this function will not accept
/// all the data.
pub(crate) fn send_some_plaintext(&mut self, data: &[u8]) -> usize {
self.send_plain(data, Limit::Yes)
}
pub(crate) fn send_early_plaintext(&mut self, data: &[u8]) -> usize {
debug_assert!(self.early_traffic);
debug_assert!(self.record_layer.is_encrypting());
if data.is_empty() {
// Don't send empty fragments.
return 0;
}
self.send_appdata_encrypt(data, Limit::Yes)
}
// Changing the keys must not span any fragmented handshake
// messages. Otherwise the defragmented messages will have
// been protected with two different record layer protections,
// which is illegal. Not mentioned in RFC.
pub(crate) fn check_aligned_handshake(&mut self) -> Result<(), Error> {
if !self.aligned_handshake {
self.send_fatal_alert(AlertDescription::UnexpectedMessage);
Err(PeerMisbehaved::KeyEpochWithPendingFragment.into())
} else {
Ok(())
}
}
pub(crate) fn illegal_param(&mut self, why: PeerMisbehaved) -> Error {
self.send_fatal_alert(AlertDescription::IllegalParameter);
Error::PeerMisbehaved(why)
}
/// Fragment `m`, encrypt the fragments, and then queue
/// the encrypted fragments for sending.
pub(crate) fn send_msg_encrypt(&mut self, m: PlainMessage) {
let iter = self
.message_fragmenter
.fragment_message(&m);
for m in iter {
self.send_single_fragment(m);
}
}
/// Like send_msg_encrypt, but operate on an appdata directly.
fn send_appdata_encrypt(&mut self, payload: &[u8], limit: Limit) -> usize {
// Here, the limit on sendable_tls applies to encrypted data,
// but we're respecting it for plaintext data -- so we'll
// be out by whatever the cipher+record overhead is. That's a
// constant and predictable amount, so it's not a terrible issue.
let len = match limit {
Limit::Yes => self
.sendable_tls
.apply_limit(payload.len()),
Limit::No => payload.len(),
};
let iter = self.message_fragmenter.fragment_slice(
ContentType::ApplicationData,
ProtocolVersion::TLSv1_2,
&payload[..len],
);
for m in iter {
self.send_single_fragment(m);
}
len
}
fn send_single_fragment(&mut self, m: BorrowedPlainMessage) {
// Close connection once we start to run out of
// sequence space.
if self
.record_layer
.wants_close_before_encrypt()
{
self.send_close_notify();
}
// Refuse to wrap counter at all costs. This
// is basically untestable unfortunately.
if self.record_layer.encrypt_exhausted() {
return;
}
let em = self.record_layer.encrypt_outgoing(m);
self.queue_tls_message(em);
}
/// Writes TLS messages to `wr`.
///
/// On success, this function returns `Ok(n)` where `n` is a number of bytes written to `wr`
/// (after encoding and encryption).
///
/// After this function returns, the connection buffer may not yet be fully flushed. The
/// [`CommonState::wants_write`] function can be used to check if the output buffer is empty.
pub fn write_tls(&mut self, wr: &mut dyn io::Write) -> Result<usize, io::Error> {
self.sendable_tls.write_to(wr)
}
/// Encrypt and send some plaintext `data`. `limit` controls
/// whether the per-connection buffer limits apply.
///
/// Returns the number of bytes written from `data`: this might
/// be less than `data.len()` if buffer limits were exceeded.
fn send_plain(&mut self, data: &[u8], limit: Limit) -> usize {
if !self.may_send_application_data {
// If we haven't completed handshaking, buffer
// plaintext to send once we do.
let len = match limit {
Limit::Yes => self
.sendable_plaintext
.append_limited_copy(data),
Limit::No => self
.sendable_plaintext
.append(data.to_vec()),
};
return len;
}
debug_assert!(self.record_layer.is_encrypting());
if data.is_empty() {
// Don't send empty fragments.
return 0;
}
self.send_appdata_encrypt(data, limit)
}
pub(crate) fn start_outgoing_traffic(&mut self) {
self.may_send_application_data = true;
self.flush_plaintext();
}
pub(crate) fn start_traffic(&mut self) {
self.may_receive_application_data = true;
self.start_outgoing_traffic();
}
/// Sets a limit on the internal buffers used to buffer
/// unsent plaintext (prior to completing the TLS handshake)
/// and unsent TLS records. This limit acts only on application
/// data written through [`Connection::writer`].
///
/// By default the limit is 64KB. The limit can be set
/// at any time, even if the current buffer use is higher.
///
/// [`None`] means no limit applies, and will mean that written
/// data is buffered without bound -- it is up to the application
/// to appropriately schedule its plaintext and TLS writes to bound
/// memory usage.
///
/// For illustration: `Some(1)` means a limit of one byte applies:
/// [`Connection::writer`] will accept only one byte, encrypt it and
/// add a TLS header. Once this is sent via [`CommonState::write_tls`],
/// another byte may be sent.
///
/// # Internal write-direction buffering
/// rustls has two buffers whose size are bounded by this setting:
///
/// ## Buffering of unsent plaintext data prior to handshake completion
///
/// Calls to [`Connection::writer`] before or during the handshake
/// are buffered (up to the limit specified here). Once the
/// handshake completes this data is encrypted and the resulting
/// TLS records are added to the outgoing buffer.
///
/// ## Buffering of outgoing TLS records
///
/// This buffer is used to store TLS records that rustls needs to
/// send to the peer. It is used in these two circumstances:
///
/// - by [`Connection::process_new_packets`] when a handshake or alert
/// TLS record needs to be sent.
/// - by [`Connection::writer`] post-handshake: the plaintext is
/// encrypted and the resulting TLS record is buffered.
///
/// This buffer is emptied by [`CommonState::write_tls`].
pub fn set_buffer_limit(&mut self, limit: Option<usize>) {
self.sendable_plaintext.set_limit(limit);
self.sendable_tls.set_limit(limit);
}
/// Send any buffered plaintext. Plaintext is buffered if
/// written during handshake.
fn flush_plaintext(&mut self) {
if !self.may_send_application_data {
return;
}
while let Some(buf) = self.sendable_plaintext.pop() {
self.send_plain(&buf, Limit::No);
}
}
// Put m into sendable_tls for writing.
fn queue_tls_message(&mut self, m: OpaqueMessage) {
self.sendable_tls.append(m.encode());
}
/// Send a raw TLS message, fragmenting it if needed.
pub(crate) fn send_msg(&mut self, m: Message, must_encrypt: bool) {
#[cfg(feature = "quic")]
{
if let Protocol::Quic = self.protocol {
if let MessagePayload::Alert(alert) = m.payload {
self.quic.alert = Some(alert.description);
} else {
debug_assert!(
matches!(m.payload, MessagePayload::Handshake { .. }),
"QUIC uses TLS for the cryptographic handshake only"
);
let mut bytes = Vec::new();
m.payload.encode(&mut bytes);
self.quic
.hs_queue
.push_back((must_encrypt, bytes));
}
return;
}
}
if !must_encrypt {
let msg = &m.into();
let iter = self
.message_fragmenter
.fragment_message(msg);
for m in iter {
self.queue_tls_message(m.to_unencrypted_opaque());
}
} else {
self.send_msg_encrypt(m.into());
}
}
pub(crate) fn take_received_plaintext(&mut self, bytes: Payload) {
self.received_plaintext.append(bytes.0);
}
#[cfg(feature = "tls12")]
pub(crate) fn start_encryption_tls12(&mut self, secrets: &ConnectionSecrets, side: Side) {
let (dec, enc) = secrets.make_cipher_pair(side);
self.record_layer
.prepare_message_encrypter(enc);
self.record_layer
.prepare_message_decrypter(dec);
}
#[cfg(feature = "quic")]
pub(crate) fn missing_extension(&mut self, why: PeerMisbehaved) -> Error {
self.send_fatal_alert(AlertDescription::MissingExtension);
Error::PeerMisbehaved(why)
}
fn send_warning_alert(&mut self, desc: AlertDescription) {
warn!("Sending warning alert {:?}", desc);
self.send_warning_alert_no_log(desc);
}
fn process_alert(&mut self, alert: &AlertMessagePayload) -> Result<(), Error> {
// Reject unknown AlertLevels.
if let AlertLevel::Unknown(_) = alert.level {
self.send_fatal_alert(AlertDescription::IllegalParameter);
return Err(Error::AlertReceived(alert.description));
}
// If we get a CloseNotify, make a note to declare EOF to our
// caller.
if alert.description == AlertDescription::CloseNotify {
self.has_received_close_notify = true;
return Ok(());
}
// Warnings are nonfatal for TLS1.2, but outlawed in TLS1.3
// (except, for no good reason, user_cancelled).
if alert.level == AlertLevel::Warning {
if self.is_tls13() && alert.description != AlertDescription::UserCanceled {
self.send_fatal_alert(AlertDescription::DecodeError);
} else {
warn!("TLS alert warning received: {:#?}", alert);
return Ok(());
}
}
error!("TLS alert received: {:#?}", alert);
Err(Error::AlertReceived(alert.description))
}
pub(crate) fn send_fatal_alert(&mut self, desc: AlertDescription) {
warn!("Sending fatal alert {:?}", desc);
debug_assert!(!self.sent_fatal_alert);
let m = Message::build_alert(AlertLevel::Fatal, desc);
self.send_msg(m, self.record_layer.is_encrypting());
self.sent_fatal_alert = true;
}
/// Queues a close_notify warning alert to be sent in the next
/// [`CommonState::write_tls`] call. This informs the peer that the
/// connection is being closed.
pub fn send_close_notify(&mut self) {
debug!("Sending warning alert {:?}", AlertDescription::CloseNotify);
self.send_warning_alert_no_log(AlertDescription::CloseNotify);
}
fn send_warning_alert_no_log(&mut self, desc: AlertDescription) {
let m = Message::build_alert(AlertLevel::Warning, desc);
self.send_msg(m, self.record_layer.is_encrypting());
}
pub(crate) fn set_max_fragment_size(&mut self, new: Option<usize>) -> Result<(), Error> {
self.message_fragmenter
.set_max_fragment_size(new)
}
pub(crate) fn get_alpn_protocol(&self) -> Option<&[u8]> {
self.alpn_protocol
.as_ref()
.map(AsRef::as_ref)
}
/// Returns true if the caller should call [`Connection::read_tls`] as soon
/// as possible.
///
/// If there is pending plaintext data to read with [`Connection::reader`],
/// this returns false. If your application respects this mechanism,
/// only one full TLS message will be buffered by rustls.
pub fn wants_read(&self) -> bool {
// We want to read more data all the time, except when we have unprocessed plaintext.
// This provides back-pressure to the TCP buffers. We also don't want to read more after
// the peer has sent us a close notification.
//
// In the handshake case we don't have readable plaintext before the handshake has
// completed, but also don't want to read if we still have sendable tls.
self.received_plaintext.is_empty()
&& !self.has_received_close_notify
&& (self.may_send_application_data || self.sendable_tls.is_empty())
}
fn current_io_state(&self) -> IoState {
IoState {
tls_bytes_to_write: self.sendable_tls.len(),
plaintext_bytes_to_read: self.received_plaintext.len(),
peer_has_closed: self.has_received_close_notify,
}
}
pub(crate) fn is_quic(&self) -> bool {
#[cfg(feature = "quic")]
{
self.protocol == Protocol::Quic
}
#[cfg(not(feature = "quic"))]
false
}
}
pub(crate) trait State<Data>: Send + Sync {
fn handle(
self: Box<Self>,
cx: &mut Context<'_, Data>,
message: Message,
) -> Result<Box<dyn State<Data>>, Error>;
fn export_keying_material(
&self,
_output: &mut [u8],
_label: &[u8],
_context: Option<&[u8]>,
) -> Result<(), Error> {
Err(Error::HandshakeNotComplete)
}
#[cfg(feature = "secret_extraction")]
fn extract_secrets(&self) -> Result<PartiallyExtractedSecrets, Error> {
Err(Error::HandshakeNotComplete)
}
fn perhaps_write_key_update(&mut self, _cx: &mut CommonState) {}
}
pub(crate) struct Context<'a, Data> {
pub(crate) common: &'a mut CommonState,
pub(crate) data: &'a mut Data,
}
#[cfg(feature = "quic")]
pub(crate) struct Quic {
/// QUIC transport parameters received from the peer during the handshake
pub(crate) params: Option<Vec<u8>>,
pub(crate) alert: Option<AlertDescription>,
pub(crate) hs_queue: VecDeque<(bool, Vec<u8>)>,
pub(crate) early_secret: Option<ring::hkdf::Prk>,
pub(crate) hs_secrets: Option<quic::Secrets>,
pub(crate) traffic_secrets: Option<quic::Secrets>,
/// Whether keys derived from traffic_secrets have been passed to the QUIC implementation
pub(crate) returned_traffic_keys: bool,
}
#[cfg(feature = "quic")]
impl Quic {
fn new() -> Self {
Self {
params: None,
alert: None,
hs_queue: VecDeque::new(),
early_secret: None,
hs_secrets: None,
traffic_secrets: None,
returned_traffic_keys: false,
}
}
}
/// Side of the connection.
#[derive(Clone, Copy, Debug, PartialEq)]
pub enum Side {
/// A client initiates the connection.
Client,
/// A server waits for a client to connect.
Server,
}
impl Side {
pub(crate) fn peer(&self) -> Self {
match self {
Self::Client => Self::Server,
Self::Server => Self::Client,
}
}
}
/// Data specific to the peer's side (client or server).
pub trait SideData {}
const DEFAULT_RECEIVED_PLAINTEXT_LIMIT: usize = 16 * 1024;
const DEFAULT_BUFFER_LIMIT: usize = 64 * 1024;