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use crate::enums::{AlertDescription, ContentType, HandshakeType, ProtocolVersion};
use crate::error::{Error, InvalidMessage, PeerMisbehaved};
use crate::key;
#[cfg(feature = "logging")]
use crate::log::{debug, warn};
use crate::msgs::alert::AlertMessagePayload;
use crate::msgs::base::Payload;
use crate::msgs::enums::{AlertLevel, KeyUpdateRequest};
use crate::msgs::fragmenter::MessageFragmenter;
#[cfg(feature = "quic")]
use crate::msgs::message::MessagePayload;
use crate::msgs::message::{BorrowedPlainMessage, Message, OpaqueMessage, PlainMessage};
#[cfg(feature = "quic")]
use crate::quic;
use crate::record_layer;
#[cfg(feature = "secret_extraction")]
use crate::suites::PartiallyExtractedSecrets;
use crate::suites::SupportedCipherSuite;
#[cfg(feature = "tls12")]
use crate::tls12::ConnectionSecrets;
use crate::vecbuf::ChunkVecBuffer;
/// 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>>,
pub(crate) 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.
pub(crate) has_received_close_notify: bool,
pub(crate) has_seen_eof: bool,
pub(crate) received_middlebox_ccs: u8,
pub(crate) peer_certificates: Option<Vec<key::Certificate>>,
message_fragmenter: MessageFragmenter,
pub(crate) received_plaintext: ChunkVecBuffer,
sendable_plaintext: ChunkVecBuffer,
pub(crate) sendable_tls: ChunkVecBuffer,
queued_key_update_message: Option<Vec<u8>>,
#[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::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)),
queued_key_update_message: None,
protocol: Protocol::Tcp,
#[cfg(feature = "quic")]
quic: quic::Quic::default(),
#[cfg(feature = "secret_extraction")]
enable_secret_extraction: false,
}
}
/// Returns true if the caller should call [`Connection::write_tls`] as soon as possible.
///
/// [`Connection::write_tls`]: crate::Connection::write_tls
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.
///
/// [`Connection::process_new_packets()`]: crate::Connection::process_new_packets
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))
}
pub(crate) 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 { .. }) => {
Err(self.send_fatal_alert(AlertDescription::UnexpectedMessage, 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.perhaps_write_key_update();
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 {
Err(self.send_fatal_alert(
AlertDescription::UnexpectedMessage,
PeerMisbehaved::KeyEpochWithPendingFragment,
))
} else {
Ok(())
}
}
/// 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);
}
/// 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 [`Connection::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 [`Connection::write_tls`].
///
/// [`Connection::writer`]: crate::Connection::writer
/// [`Connection::write_tls`]: crate::Connection::write_tls
/// [`Connection::process_new_packets`]: crate::Connection::process_new_packets
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, why)
}
fn send_warning_alert(&mut self, desc: AlertDescription) {
warn!("Sending warning alert {:?}", desc);
self.send_warning_alert_no_log(desc);
}
pub(crate) fn process_alert(&mut self, alert: &AlertMessagePayload) -> Result<(), Error> {
// Reject unknown AlertLevels.
if let AlertLevel::Unknown(_) = alert.level {
return Err(self.send_fatal_alert(
AlertDescription::IllegalParameter,
Error::AlertReceived(alert.description),
));
}
// If we get a CloseNotify, make a note to declare EOF to our
// caller. But do not treat unauthenticated alerts like this.
if self.may_receive_application_data && 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).
let err = Error::AlertReceived(alert.description);
if alert.level == AlertLevel::Warning {
if self.is_tls13() && alert.description != AlertDescription::UserCanceled {
return Err(self.send_fatal_alert(AlertDescription::DecodeError, err));
} else {
warn!("TLS alert warning received: {:#?}", alert);
return Ok(());
}
}
Err(err)
}
pub(crate) fn send_cert_verify_error_alert(&mut self, err: Error) -> Error {
self.send_fatal_alert(
match &err {
Error::InvalidCertificate(e) => e.clone().into(),
Error::PeerMisbehaved(_) => AlertDescription::IllegalParameter,
_ => AlertDescription::HandshakeFailure,
},
err,
)
}
pub(crate) fn send_fatal_alert(
&mut self,
desc: AlertDescription,
err: impl Into<Error>,
) -> Error {
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;
err.into()
}
/// Queues a close_notify warning alert to be sent in the next
/// [`Connection::write_tls`] call. This informs the peer that the
/// connection is being closed.
///
/// [`Connection::write_tls`]: crate::Connection::write_tls
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.
///
/// [`Connection::reader`]: crate::Connection::reader
/// [`Connection::read_tls`]: crate::Connection::read_tls
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())
}
pub(crate) 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) fn should_update_key(
&mut self,
key_update_request: &KeyUpdateRequest,
) -> Result<bool, Error> {
match key_update_request {
KeyUpdateRequest::UpdateNotRequested => Ok(false),
KeyUpdateRequest::UpdateRequested => Ok(self.queued_key_update_message.is_none()),
_ => Err(self.send_fatal_alert(
AlertDescription::IllegalParameter,
InvalidMessage::InvalidKeyUpdate,
)),
}
}
pub(crate) fn enqueue_key_update_notification(&mut self) {
let message = PlainMessage::from(Message::build_key_update_notify());
self.queued_key_update_message = Some(
self.record_layer
.encrypt_outgoing(message.borrow())
.encode(),
);
}
pub(crate) fn perhaps_write_key_update(&mut self) {
if let Some(message) = self.queued_key_update_message.take() {
self.sendable_tls.append(message);
}
}
}
/// Values of this structure are returned from [`Connection::process_new_packets`]
/// and tell the caller the current I/O state of the TLS connection.
///
/// [`Connection::process_new_packets`]: crate::Connection::process_new_packets
#[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 [`Connection::write_tls`] if called
/// right now. A non-zero value implies [`CommonState::wants_write`].
///
/// [`Connection::write_tls`]: crate::Connection::write_tls
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
}
}
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 handle_decrypt_error(&self) {}
}
pub(crate) struct Context<'a, Data> {
pub(crate) common: &'a mut CommonState,
pub(crate) data: &'a mut Data,
}
/// 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,
}
}
}
#[derive(Copy, Clone, Eq, PartialEq, Debug)]
pub(crate) enum Protocol {
Tcp,
#[cfg(feature = "quic")]
Quic,
}
enum Limit {
Yes,
No,
}
const DEFAULT_RECEIVED_PLAINTEXT_LIMIT: usize = 16 * 1024;
const DEFAULT_BUFFER_LIMIT: usize = 64 * 1024;