1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978
use alloc::boxed::Box;
use alloc::vec::Vec;
use pki_types::CertificateDer;
use crate::crypto::SupportedKxGroup;
use crate::enums::{AlertDescription, ContentType, HandshakeType, ProtocolVersion};
use crate::error::{Error, InvalidMessage, PeerMisbehaved};
use crate::log::{debug, error, warn};
use crate::msgs::alert::AlertMessagePayload;
use crate::msgs::base::Payload;
use crate::msgs::enums::{AlertLevel, KeyUpdateRequest};
use crate::msgs::fragmenter::MessageFragmenter;
use crate::msgs::handshake::CertificateChain;
use crate::msgs::message::{
Message, MessagePayload, OutboundChunks, OutboundOpaqueMessage, OutboundPlainMessage,
PlainMessage,
};
use crate::record_layer::PreEncryptAction;
use crate::suites::{PartiallyExtractedSecrets, SupportedCipherSuite};
#[cfg(feature = "tls12")]
use crate::tls12::ConnectionSecrets;
use crate::unbuffered::{EncryptError, InsufficientSizeError};
use crate::vecbuf::ChunkVecBuffer;
use crate::{quic, record_layer};
/// Connection state common to both client and server connections.
pub struct CommonState {
pub(crate) negotiated_version: Option<ProtocolVersion>,
pub(crate) handshake_kind: Option<HandshakeKind>,
pub(crate) side: Side,
pub(crate) record_layer: record_layer::RecordLayer,
pub(crate) suite: Option<SupportedCipherSuite>,
pub(crate) kx_state: KxState,
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,
#[cfg(feature = "std")]
pub(crate) has_seen_eof: bool,
pub(crate) peer_certificates: Option<CertificateChain<'static>>,
message_fragmenter: MessageFragmenter,
pub(crate) received_plaintext: ChunkVecBuffer,
pub(crate) sendable_tls: ChunkVecBuffer,
queued_key_update_message: Option<Vec<u8>>,
/// Protocol whose key schedule should be used. Unused for TLS < 1.3.
pub(crate) protocol: Protocol,
pub(crate) quic: quic::Quic,
pub(crate) enable_secret_extraction: bool,
temper_counters: TemperCounters,
pub(crate) refresh_traffic_keys_pending: bool,
}
impl CommonState {
pub(crate) fn new(side: Side) -> Self {
Self {
negotiated_version: None,
handshake_kind: None,
side,
record_layer: record_layer::RecordLayer::new(),
suite: None,
kx_state: KxState::default(),
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,
#[cfg(feature = "std")]
has_seen_eof: false,
peer_certificates: None,
message_fragmenter: MessageFragmenter::default(),
received_plaintext: ChunkVecBuffer::new(Some(DEFAULT_RECEIVED_PLAINTEXT_LIMIT)),
sendable_tls: ChunkVecBuffer::new(Some(DEFAULT_BUFFER_LIMIT)),
queued_key_update_message: None,
protocol: Protocol::Tcp,
quic: quic::Quic::default(),
enable_secret_extraction: false,
temper_counters: TemperCounters::default(),
refresh_traffic_keys_pending: 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<&[CertificateDer<'static>]> {
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 key exchange group agreed with the peer.
///
/// This function may return `None` depending on the state of the connection,
/// the type of handshake, and the protocol version.
///
/// If [`CommonState::is_handshaking()`] is true this function will return `None`.
/// Similarly, if the [`CommonState::handshake_kind()`] is [`HandshakeKind::Resumed`]
/// and the [`CommonState::protocol_version()`] is TLS 1.2, then no key exchange will have
/// occurred and this function will return `None`.
pub fn negotiated_key_exchange_group(&self) -> Option<&'static dyn SupportedKxGroup> {
match self.kx_state {
KxState::Complete(group) => Some(group),
_ => None,
}
}
/// 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
}
/// Which kind of handshake was performed.
///
/// This tells you whether the handshake was a resumption or not.
///
/// This will return `None` before it is known which sort of
/// handshake occurred.
pub fn handshake_kind(&self) -> Option<HandshakeKind> {
self.handshake_kind
}
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,
sendable_plaintext: Option<&mut ChunkVecBuffer>,
) -> 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.temper_counters
.received_renegotiation_request()?;
self.send_warning_alert(AlertDescription::NoRenegotiation);
return Ok(state);
}
}
let mut cx = Context {
common: self,
data,
sendable_plaintext,
};
match state.handle(&mut cx, msg) {
Ok(next) => {
state = next.into_owned();
Ok(state)
}
Err(e @ Error::InappropriateMessage { .. })
| Err(e @ Error::InappropriateHandshakeMessage { .. }) => {
Err(self.send_fatal_alert(AlertDescription::UnexpectedMessage, e))
}
Err(e) => Err(e),
}
}
pub(crate) fn write_plaintext(
&mut self,
payload: OutboundChunks<'_>,
outgoing_tls: &mut [u8],
) -> Result<usize, EncryptError> {
if payload.is_empty() {
return Ok(0);
}
let fragments = self
.message_fragmenter
.fragment_payload(
ContentType::ApplicationData,
ProtocolVersion::TLSv1_2,
payload.clone(),
);
for f in 0..fragments.len() {
match self
.record_layer
.pre_encrypt_action(f as u64)
{
PreEncryptAction::Nothing => {}
PreEncryptAction::RefreshOrClose => match self.negotiated_version {
Some(ProtocolVersion::TLSv1_3) => {
// driven by caller, as we don't have the `State` here
self.refresh_traffic_keys_pending = true;
}
_ => {
error!("traffic keys exhausted, closing connection to prevent security failure");
self.send_close_notify();
return Err(EncryptError::EncryptExhausted);
}
},
PreEncryptAction::Refuse => {
return Err(EncryptError::EncryptExhausted);
}
}
}
self.perhaps_write_key_update();
self.check_required_size(outgoing_tls, fragments)?;
let fragments = self
.message_fragmenter
.fragment_payload(
ContentType::ApplicationData,
ProtocolVersion::TLSv1_2,
payload,
);
Ok(self.write_fragments(outgoing_tls, fragments))
}
// 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: OutboundChunks<'_>, 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 {
#[cfg(feature = "std")]
Limit::Yes => self
.sendable_tls
.apply_limit(payload.len()),
Limit::No => payload.len(),
};
let iter = self
.message_fragmenter
.fragment_payload(
ContentType::ApplicationData,
ProtocolVersion::TLSv1_2,
payload.split_at(len).0,
);
for m in iter {
self.send_single_fragment(m);
}
len
}
fn send_single_fragment(&mut self, m: OutboundPlainMessage<'_>) {
if m.typ == ContentType::Alert {
// Alerts are always sendable -- never quashed by a PreEncryptAction.
let em = self.record_layer.encrypt_outgoing(m);
self.queue_tls_message(em);
return;
}
match self
.record_layer
.next_pre_encrypt_action()
{
PreEncryptAction::Nothing => {}
// Close connection once we start to run out of
// sequence space.
PreEncryptAction::RefreshOrClose => {
match self.negotiated_version {
Some(ProtocolVersion::TLSv1_3) => {
// driven by caller, as we don't have the `State` here
self.refresh_traffic_keys_pending = true;
}
_ => {
error!("traffic keys exhausted, closing connection to prevent security failure");
self.send_close_notify();
return;
}
}
}
// Refuse to wrap counter at all costs. This
// is basically untestable unfortunately.
PreEncryptAction::Refuse => {
return;
}
};
let em = self.record_layer.encrypt_outgoing(m);
self.queue_tls_message(em);
}
fn send_plain_non_buffering(&mut self, payload: OutboundChunks<'_>, limit: Limit) -> usize {
debug_assert!(self.may_send_application_data);
debug_assert!(self.record_layer.is_encrypting());
if payload.is_empty() {
// Don't send empty fragments.
return 0;
}
self.send_appdata_encrypt(payload, limit)
}
/// Mark the connection as ready to send application data.
///
/// Also flush `sendable_plaintext` if it is `Some`.
pub(crate) fn start_outgoing_traffic(
&mut self,
sendable_plaintext: &mut Option<&mut ChunkVecBuffer>,
) {
self.may_send_application_data = true;
if let Some(sendable_plaintext) = sendable_plaintext {
self.flush_plaintext(sendable_plaintext);
}
}
/// Mark the connection as ready to send and receive application data.
///
/// Also flush `sendable_plaintext` if it is `Some`.
pub(crate) fn start_traffic(&mut self, sendable_plaintext: &mut Option<&mut ChunkVecBuffer>) {
self.may_receive_application_data = true;
self.start_outgoing_traffic(sendable_plaintext);
}
/// Send any buffered plaintext. Plaintext is buffered if
/// written during handshake.
fn flush_plaintext(&mut self, sendable_plaintext: &mut ChunkVecBuffer) {
if !self.may_send_application_data {
return;
}
while let Some(buf) = sendable_plaintext.pop() {
self.send_plain_non_buffering(buf.as_slice().into(), Limit::No);
}
}
// Put m into sendable_tls for writing.
fn queue_tls_message(&mut self, m: OutboundOpaqueMessage) {
self.perhaps_write_key_update();
self.sendable_tls.append(m.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);
}
}
/// Send a raw TLS message, fragmenting it if needed.
pub(crate) fn send_msg(&mut self, m: Message<'_>, must_encrypt: bool) {
{
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.into_vec());
}
#[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,
secrets
.suite()
.common
.confidentiality_limit,
);
self.record_layer
.prepare_message_decrypter(dec);
}
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 {
self.temper_counters
.received_warning_alert()?;
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.
///
/// Does nothing if any `close_notify` or fatal alert was already sent.
///
/// [`Connection::write_tls`]: crate::Connection::write_tls
pub fn send_close_notify(&mut self) {
if self.sent_fatal_alert {
return;
}
debug!("Sending warning alert {:?}", AlertDescription::CloseNotify);
self.sent_fatal_alert = true;
self.send_warning_alert_no_log(AlertDescription::CloseNotify);
}
pub(crate) fn eager_send_close_notify(
&mut self,
outgoing_tls: &mut [u8],
) -> Result<usize, EncryptError> {
self.send_close_notify();
self.check_required_size(outgoing_tls, [].into_iter())?;
Ok(self.write_fragments(outgoing_tls, [].into_iter()))
}
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());
}
fn check_required_size<'a>(
&self,
outgoing_tls: &mut [u8],
fragments: impl Iterator<Item = OutboundPlainMessage<'a>>,
) -> Result<(), EncryptError> {
let mut required_size = self.sendable_tls.len();
for m in fragments {
required_size += m.encoded_len(&self.record_layer);
}
if required_size > outgoing_tls.len() {
return Err(EncryptError::InsufficientSize(InsufficientSizeError {
required_size,
}));
}
Ok(())
}
fn write_fragments<'a>(
&mut self,
outgoing_tls: &mut [u8],
fragments: impl Iterator<Item = OutboundPlainMessage<'a>>,
) -> usize {
let mut written = 0;
// Any pre-existing encrypted messages in `sendable_tls` must
// be output before encrypting any of the `fragments`.
while let Some(message) = self.sendable_tls.pop() {
let len = message.len();
outgoing_tls[written..written + len].copy_from_slice(&message);
written += len;
}
for m in fragments {
let em = self
.record_layer
.encrypt_outgoing(m)
.encode();
let len = em.len();
outgoing_tls[written..written + len].copy_from_slice(&em);
written += len;
}
written
}
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 {
self.protocol == Protocol::Quic
}
pub(crate) fn should_update_key(
&mut self,
key_update_request: &KeyUpdateRequest,
) -> Result<bool, Error> {
self.temper_counters
.received_key_update_request()?;
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_outbound())
.encode(),
);
}
pub(crate) fn received_tls13_change_cipher_spec(&mut self) -> Result<(), Error> {
self.temper_counters
.received_tls13_change_cipher_spec()
}
}
#[cfg(feature = "std")]
impl CommonState {
/// 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 buffer_plaintext(
&mut self,
payload: OutboundChunks<'_>,
sendable_plaintext: &mut ChunkVecBuffer,
) -> usize {
self.perhaps_write_key_update();
self.send_plain(payload, Limit::Yes, sendable_plaintext)
}
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.into(), Limit::Yes)
}
/// 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,
payload: OutboundChunks<'_>,
limit: Limit,
sendable_plaintext: &mut ChunkVecBuffer,
) -> 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 => sendable_plaintext.append_limited_copy(payload),
Limit::No => sendable_plaintext.append(payload.to_vec()),
};
return len;
}
self.send_plain_non_buffering(payload, limit)
}
}
/// Describes which sort of handshake happened.
#[derive(Debug, PartialEq, Clone, Copy)]
pub enum HandshakeKind {
/// A full handshake.
///
/// This is the typical TLS connection initiation process when resumption is
/// not yet unavailable, and the initial `ClientHello` was accepted by the server.
Full,
/// A full TLS1.3 handshake, with an extra round-trip for a `HelloRetryRequest`.
///
/// The server can respond with a `HelloRetryRequest` if the initial `ClientHello`
/// is unacceptable for several reasons, the most likely if no supported key
/// shares were offered by the client.
FullWithHelloRetryRequest,
/// A resumed handshake.
///
/// Resumed handshakes involve fewer round trips and less cryptography than
/// full ones, but can only happen when the peers have previously done a full
/// handshake together, and then remember data about it.
Resumed,
}
/// 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<'m>(
self: Box<Self>,
cx: &mut Context<'_, Data>,
message: Message<'m>,
) -> Result<Box<dyn State<Data> + 'm>, Error>
where
Self: 'm;
fn export_keying_material(
&self,
_output: &mut [u8],
_label: &[u8],
_context: Option<&[u8]>,
) -> Result<(), Error> {
Err(Error::HandshakeNotComplete)
}
fn extract_secrets(&self) -> Result<PartiallyExtractedSecrets, Error> {
Err(Error::HandshakeNotComplete)
}
fn send_key_update_request(&mut self, _common: &mut CommonState) -> Result<(), Error> {
Err(Error::HandshakeNotComplete)
}
fn handle_decrypt_error(&self) {}
fn into_owned(self: Box<Self>) -> Box<dyn State<Data> + 'static>;
}
pub(crate) struct Context<'a, Data> {
pub(crate) common: &'a mut CommonState,
pub(crate) data: &'a mut Data,
/// Buffered plaintext. This is `Some` if any plaintext was written during handshake and `None`
/// otherwise.
pub(crate) sendable_plaintext: Option<&'a mut ChunkVecBuffer>,
}
/// 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,
Quic,
}
enum Limit {
#[cfg(feature = "std")]
Yes,
No,
}
/// Tracking technically-allowed protocol actions
/// that we limit to avoid denial-of-service vectors.
struct TemperCounters {
allowed_warning_alerts: u8,
allowed_renegotiation_requests: u8,
allowed_key_update_requests: u8,
allowed_middlebox_ccs: u8,
}
impl TemperCounters {
fn received_warning_alert(&mut self) -> Result<(), Error> {
match self.allowed_warning_alerts {
0 => Err(PeerMisbehaved::TooManyWarningAlertsReceived.into()),
_ => {
self.allowed_warning_alerts -= 1;
Ok(())
}
}
}
fn received_renegotiation_request(&mut self) -> Result<(), Error> {
match self.allowed_renegotiation_requests {
0 => Err(PeerMisbehaved::TooManyRenegotiationRequests.into()),
_ => {
self.allowed_renegotiation_requests -= 1;
Ok(())
}
}
}
fn received_key_update_request(&mut self) -> Result<(), Error> {
match self.allowed_key_update_requests {
0 => Err(PeerMisbehaved::TooManyKeyUpdateRequests.into()),
_ => {
self.allowed_key_update_requests -= 1;
Ok(())
}
}
}
fn received_tls13_change_cipher_spec(&mut self) -> Result<(), Error> {
match self.allowed_middlebox_ccs {
0 => Err(PeerMisbehaved::IllegalMiddleboxChangeCipherSpec.into()),
_ => {
self.allowed_middlebox_ccs -= 1;
Ok(())
}
}
}
}
impl Default for TemperCounters {
fn default() -> Self {
Self {
// cf. BoringSSL `kMaxWarningAlerts`
// <https://github.com/google/boringssl/blob/dec5989b793c56ad4dd32173bd2d8595ca78b398/ssl/tls_record.cc#L137-L139>
allowed_warning_alerts: 4,
// we rebuff renegotiation requests with a `NoRenegotiation` warning alerts.
// a second request after this is fatal.
allowed_renegotiation_requests: 1,
// cf. BoringSSL `kMaxKeyUpdates`
// <https://github.com/google/boringssl/blob/dec5989b793c56ad4dd32173bd2d8595ca78b398/ssl/tls13_both.cc#L35-L38>
allowed_key_update_requests: 32,
// At most two CCS are allowed: one after each ClientHello (recall a second
// ClientHello happens after a HelloRetryRequest).
//
// note BoringSSL allows up to 32.
allowed_middlebox_ccs: 2,
}
}
}
#[derive(Debug, Default)]
pub(crate) enum KxState {
#[default]
None,
Start(&'static dyn SupportedKxGroup),
Complete(&'static dyn SupportedKxGroup),
}
impl KxState {
pub(crate) fn complete(&mut self) {
debug_assert!(matches!(self, Self::Start(_)));
if let Self::Start(group) = self {
*self = Self::Complete(*group);
}
}
}
const DEFAULT_RECEIVED_PLAINTEXT_LIMIT: usize = 16 * 1024;
pub(crate) const DEFAULT_BUFFER_LIMIT: usize = 64 * 1024;