rustls/rustls/src/client/tls13.rs

use crate::check::inappropriate_handshake_message;
use crate::common_state::Protocol;
use crate::common_state::{CommonState, Side, State};
use crate::conn::ConnectionRandoms;
use crate::crypto;
use crate::crypto::ActiveKeyExchange;
use crate::enums::{
    AlertDescription, ContentType, HandshakeType, ProtocolVersion, SignatureScheme,
};
use crate::error::{Error, InvalidMessage, PeerIncompatible, PeerMisbehaved};
use crate::hash_hs::{HandshakeHash, HandshakeHashBuffer};
#[cfg(feature = "logging")]
use crate::log::{debug, trace, warn};
use crate::msgs::base::{Payload, PayloadU8};
use crate::msgs::ccs::ChangeCipherSpecPayload;
use crate::msgs::enums::ExtensionType;
use crate::msgs::enums::KeyUpdateRequest;
use crate::msgs::handshake::NewSessionTicketPayloadTls13;
use crate::msgs::handshake::{CertificateEntry, CertificatePayloadTls13};
use crate::msgs::handshake::{ClientExtension, ServerExtension};
use crate::msgs::handshake::{HandshakeMessagePayload, HandshakePayload};
use crate::msgs::handshake::{HasServerExtensions, ServerHelloPayload};
use crate::msgs::handshake::{PresharedKeyIdentity, PresharedKeyOffer};
use crate::msgs::message::{Message, MessagePayload};
use crate::msgs::persist;
use crate::sign::{CertifiedKey, Signer};
use crate::suites::PartiallyExtractedSecrets;
use crate::tls13::construct_client_verify_message;
use crate::tls13::construct_server_verify_message;
use crate::tls13::key_schedule::{
    KeyScheduleEarly, KeyScheduleHandshake, KeySchedulePreHandshake, KeyScheduleTraffic,
};
use crate::tls13::Tls13CipherSuite;
use crate::verify::{self, DigitallySignedStruct};
use crate::KeyLog;

use super::client_conn::ClientConnectionData;
use super::hs::ClientContext;
use crate::client::common::ServerCertDetails;
use crate::client::common::{ClientAuthDetails, ClientHelloDetails};
use crate::client::{hs, ClientConfig, ClientSessionStore};

use pki_types::{ServerName, UnixTime};
use subtle::ConstantTimeEq;

use alloc::boxed::Box;
use alloc::sync::Arc;
use alloc::vec;
use alloc::vec::Vec;

// Extensions we expect in plaintext in the ServerHello.
static ALLOWED_PLAINTEXT_EXTS: &[ExtensionType] = &[
    ExtensionType::KeyShare,
    ExtensionType::PreSharedKey,
    ExtensionType::SupportedVersions,
];

// Only the intersection of things we offer, and those disallowed
// in TLS1.3
static DISALLOWED_TLS13_EXTS: &[ExtensionType] = &[
    ExtensionType::ECPointFormats,
    ExtensionType::SessionTicket,
    ExtensionType::RenegotiationInfo,
    ExtensionType::ExtendedMasterSecret,
];

pub(super) fn handle_server_hello(
    config: Arc<ClientConfig>,
    cx: &mut ClientContext,
    server_hello: &ServerHelloPayload,
    mut resuming_session: Option<persist::Tls13ClientSessionValue>,
    server_name: ServerName<'static>,
    randoms: ConnectionRandoms,
    suite: &'static Tls13CipherSuite,
    transcript: HandshakeHash,
    early_key_schedule: Option<KeyScheduleEarly>,
    hello: ClientHelloDetails,
    our_key_share: Box<dyn ActiveKeyExchange>,
    mut sent_tls13_fake_ccs: bool,
) -> hs::NextStateOrError<'static> {
    validate_server_hello(cx.common, server_hello)?;

    let their_key_share = server_hello
        .key_share()
        .ok_or_else(|| {
            cx.common.send_fatal_alert(
                AlertDescription::MissingExtension,
                PeerMisbehaved::MissingKeyShare,
            )
        })?;

    if our_key_share.group() != their_key_share.group {
        return Err({
            cx.common.send_fatal_alert(
                AlertDescription::IllegalParameter,
                PeerMisbehaved::WrongGroupForKeyShare,
            )
        });
    }

    let key_schedule_pre_handshake = if let (Some(selected_psk), Some(early_key_schedule)) =
        (server_hello.psk_index(), early_key_schedule)
    {
        if let Some(ref resuming) = resuming_session {
            let resuming_suite = match suite.can_resume_from(resuming.suite()) {
                Some(resuming) => resuming,
                None => {
                    return Err({
                        cx.common.send_fatal_alert(
                            AlertDescription::IllegalParameter,
                            PeerMisbehaved::ResumptionOfferedWithIncompatibleCipherSuite,
                        )
                    });
                }
            };

            // If the server varies the suite here, we will have encrypted early data with
            // the wrong suite.
            if cx.data.early_data.is_enabled() && resuming_suite != suite {
                return Err({
                    cx.common.send_fatal_alert(
                        AlertDescription::IllegalParameter,
                        PeerMisbehaved::EarlyDataOfferedWithVariedCipherSuite,
                    )
                });
            }

            if selected_psk != 0 {
                return Err({
                    cx.common.send_fatal_alert(
                        AlertDescription::IllegalParameter,
                        PeerMisbehaved::SelectedInvalidPsk,
                    )
                });
            }

            debug!("Resuming using PSK");
            // The key schedule has been initialized and set in fill_in_psk_binder()
        } else {
            return Err(PeerMisbehaved::SelectedUnofferedPsk.into());
        }
        KeySchedulePreHandshake::from(early_key_schedule)
    } else {
        debug!("Not resuming");
        // Discard the early data key schedule.
        cx.data.early_data.rejected();
        cx.common.early_traffic = false;
        resuming_session.take();
        KeySchedulePreHandshake::new(suite)
    };

    let key_schedule =
        key_schedule_pre_handshake.into_handshake(our_key_share, &their_key_share.payload.0)?;

    // Remember what KX group the server liked for next time.
    config
        .resumption
        .store
        .set_kx_hint(server_name.clone(), their_key_share.group);

    // If we change keying when a subsequent handshake message is being joined,
    // the two halves will have different record layer protections.  Disallow this.
    cx.common.check_aligned_handshake()?;

    let hash_at_client_recvd_server_hello = transcript.current_hash();
    let key_schedule = key_schedule.derive_client_handshake_secrets(
        cx.data.early_data.is_enabled(),
        hash_at_client_recvd_server_hello,
        suite,
        &*config.key_log,
        &randoms.client,
        cx.common,
    );

    emit_fake_ccs(&mut sent_tls13_fake_ccs, cx.common);

    Ok(Box::new(ExpectEncryptedExtensions {
        config,
        resuming_session,
        server_name,
        randoms,
        suite,
        transcript,
        key_schedule,
        hello,
    }))
}

fn validate_server_hello(
    common: &mut CommonState,
    server_hello: &ServerHelloPayload,
) -> Result<(), Error> {
    for ext in &server_hello.extensions {
        if !ALLOWED_PLAINTEXT_EXTS.contains(&ext.ext_type()) {
            return Err(common.send_fatal_alert(
                AlertDescription::UnsupportedExtension,
                PeerMisbehaved::UnexpectedCleartextExtension,
            ));
        }
    }

    Ok(())
}

pub(super) fn initial_key_share(
    config: &ClientConfig,
    server_name: &ServerName<'_>,
) -> Result<Box<dyn ActiveKeyExchange>, Error> {
    let group = config
        .resumption
        .store
        .kx_hint(server_name)
        .and_then(|group_name| {
            config
                .provider
                .find_kx_group(group_name)
        })
        .unwrap_or_else(|| {
            config
                .provider
                .kx_groups
                .iter()
                .copied()
                .next()
                .expect("No kx groups configured")
        });

    group.start()
}

/// This implements the horrifying TLS1.3 hack where PSK binders have a
/// data dependency on the message they are contained within.
pub(super) fn fill_in_psk_binder(
    resuming: &persist::Tls13ClientSessionValue,
    transcript: &HandshakeHashBuffer,
    hmp: &mut HandshakeMessagePayload,
) -> KeyScheduleEarly {
    // We need to know the hash function of the suite we're trying to resume into.
    let suite = resuming.suite();
    let suite_hash = suite.common.hash_provider;

    // The binder is calculated over the clienthello, but doesn't include itself or its
    // length, or the length of its container.
    let binder_plaintext = hmp.encoding_for_binder_signing();
    let handshake_hash = transcript.hash_given(suite_hash, &binder_plaintext);

    // Run a fake key_schedule to simulate what the server will do if it chooses
    // to resume.
    let key_schedule = KeyScheduleEarly::new(suite, resuming.secret());
    let real_binder = key_schedule.resumption_psk_binder_key_and_sign_verify_data(&handshake_hash);

    if let HandshakePayload::ClientHello(ref mut ch) = hmp.payload {
        ch.set_psk_binder(real_binder.as_ref());
    };

    key_schedule
}

pub(super) fn prepare_resumption(
    config: &ClientConfig,
    cx: &mut ClientContext<'_>,
    resuming_session: &persist::Retrieved<&persist::Tls13ClientSessionValue>,
    exts: &mut Vec<ClientExtension>,
    doing_retry: bool,
) {
    let resuming_suite = resuming_session.suite();
    cx.common.suite = Some(resuming_suite.into());
    cx.data.resumption_ciphersuite = Some(resuming_suite.into());
    // The EarlyData extension MUST be supplied together with the
    // PreSharedKey extension.
    let max_early_data_size = resuming_session.max_early_data_size();
    if config.enable_early_data && max_early_data_size > 0 && !doing_retry {
        cx.data
            .early_data
            .enable(max_early_data_size as usize);
        exts.push(ClientExtension::EarlyData);
    }

    // Finally, and only for TLS1.3 with a ticket resumption, include a binder
    // for our ticket.  This must go last.
    //
    // Include an empty binder. It gets filled in below because it depends on
    // the message it's contained in (!!!).
    let obfuscated_ticket_age = resuming_session.obfuscated_ticket_age();

    let binder_len = resuming_suite
        .common
        .hash_provider
        .output_len();
    let binder = vec![0u8; binder_len];

    let psk_identity =
        PresharedKeyIdentity::new(resuming_session.ticket().to_vec(), obfuscated_ticket_age);
    let psk_ext = PresharedKeyOffer::new(psk_identity, binder);
    exts.push(ClientExtension::PresharedKey(psk_ext));
}

pub(super) fn derive_early_traffic_secret(
    key_log: &dyn KeyLog,
    cx: &mut ClientContext<'_>,
    resuming_suite: &'static Tls13CipherSuite,
    early_key_schedule: &KeyScheduleEarly,
    sent_tls13_fake_ccs: &mut bool,
    transcript_buffer: &HandshakeHashBuffer,
    client_random: &[u8; 32],
) {
    // For middlebox compatibility
    emit_fake_ccs(sent_tls13_fake_ccs, cx.common);

    let client_hello_hash = transcript_buffer.hash_given(resuming_suite.common.hash_provider, &[]);
    early_key_schedule.client_early_traffic_secret(
        &client_hello_hash,
        key_log,
        client_random,
        cx.common,
    );

    // Now the client can send encrypted early data
    cx.common.early_traffic = true;
    trace!("Starting early data traffic");
}

pub(super) fn emit_fake_ccs(sent_tls13_fake_ccs: &mut bool, common: &mut CommonState) {
    if common.is_quic() {
        return;
    }

    if core::mem::replace(sent_tls13_fake_ccs, true) {
        return;
    }

    let m = Message {
        version: ProtocolVersion::TLSv1_2,
        payload: MessagePayload::ChangeCipherSpec(ChangeCipherSpecPayload {}),
    };
    common.send_msg(m, false);
}

fn validate_encrypted_extensions(
    common: &mut CommonState,
    hello: &ClientHelloDetails,
    exts: &Vec<ServerExtension>,
) -> Result<(), Error> {
    if exts.has_duplicate_extension() {
        return Err(common.send_fatal_alert(
            AlertDescription::DecodeError,
            PeerMisbehaved::DuplicateEncryptedExtensions,
        ));
    }

    if hello.server_sent_unsolicited_extensions(exts, &[]) {
        return Err(common.send_fatal_alert(
            AlertDescription::UnsupportedExtension,
            PeerMisbehaved::UnsolicitedEncryptedExtension,
        ));
    }

    for ext in exts {
        if ALLOWED_PLAINTEXT_EXTS.contains(&ext.ext_type())
            || DISALLOWED_TLS13_EXTS.contains(&ext.ext_type())
        {
            return Err(common.send_fatal_alert(
                AlertDescription::UnsupportedExtension,
                PeerMisbehaved::DisallowedEncryptedExtension,
            ));
        }
    }

    Ok(())
}

struct ExpectEncryptedExtensions {
    config: Arc<ClientConfig>,
    resuming_session: Option<persist::Tls13ClientSessionValue>,
    server_name: ServerName<'static>,
    randoms: ConnectionRandoms,
    suite: &'static Tls13CipherSuite,
    transcript: HandshakeHash,
    key_schedule: KeyScheduleHandshake,
    hello: ClientHelloDetails,
}

impl State<ClientConnectionData> for ExpectEncryptedExtensions {
    fn handle<'m>(
        mut self: Box<Self>,
        cx: &mut ClientContext<'_>,
        m: Message<'m>,
    ) -> hs::NextStateOrError<'m>
    where
        Self: 'm,
    {
        let exts = require_handshake_msg!(
            m,
            HandshakeType::EncryptedExtensions,
            HandshakePayload::EncryptedExtensions
        )?;
        debug!("TLS1.3 encrypted extensions: {:?}", exts);
        self.transcript.add_message(&m);

        validate_encrypted_extensions(cx.common, &self.hello, exts)?;
        hs::process_alpn_protocol(cx.common, &self.config, exts.alpn_protocol())?;

        // QUIC transport parameters
        if cx.common.is_quic() {
            match exts.quic_params_extension() {
                Some(params) => cx.common.quic.params = Some(params),
                None => {
                    return Err(cx
                        .common
                        .missing_extension(PeerMisbehaved::MissingQuicTransportParameters));
                }
            }
        }

        if let Some(resuming_session) = self.resuming_session {
            let was_early_traffic = cx.common.early_traffic;
            if was_early_traffic {
                if exts.early_data_extension_offered() {
                    cx.data.early_data.accepted();
                } else {
                    cx.data.early_data.rejected();
                    cx.common.early_traffic = false;
                }
            }

            if was_early_traffic && !cx.common.early_traffic {
                // If no early traffic, set the encryption key for handshakes
                self.key_schedule
                    .set_handshake_encrypter(cx.common);
            }

            cx.common.peer_certificates = Some(
                resuming_session
                    .server_cert_chain()
                    .clone(),
            );

            // We *don't* reverify the certificate chain here: resumption is a
            // continuation of the previous session in terms of security policy.
            let cert_verified = verify::ServerCertVerified::assertion();
            let sig_verified = verify::HandshakeSignatureValid::assertion();
            Ok(Box::new(ExpectFinished {
                config: self.config,
                server_name: self.server_name,
                randoms: self.randoms,
                suite: self.suite,
                transcript: self.transcript,
                key_schedule: self.key_schedule,
                client_auth: None,
                cert_verified,
                sig_verified,
            }))
        } else {
            if exts.early_data_extension_offered() {
                return Err(PeerMisbehaved::EarlyDataExtensionWithoutResumption.into());
            }
            Ok(Box::new(ExpectCertificateOrCertReq {
                config: self.config,
                server_name: self.server_name,
                randoms: self.randoms,
                suite: self.suite,
                transcript: self.transcript,
                key_schedule: self.key_schedule,
            }))
        }
    }

    fn into_owned(self: Box<Self>) -> hs::NextState<'static> {
        self
    }
}

struct ExpectCertificateOrCertReq {
    config: Arc<ClientConfig>,
    server_name: ServerName<'static>,
    randoms: ConnectionRandoms,
    suite: &'static Tls13CipherSuite,
    transcript: HandshakeHash,
    key_schedule: KeyScheduleHandshake,
}

impl State<ClientConnectionData> for ExpectCertificateOrCertReq {
    fn handle<'m>(
        self: Box<Self>,
        cx: &mut ClientContext<'_>,
        m: Message<'m>,
    ) -> hs::NextStateOrError<'m>
    where
        Self: 'm,
    {
        match m.payload {
            MessagePayload::Handshake {
                parsed:
                    HandshakeMessagePayload {
                        payload: HandshakePayload::CertificateTls13(..),
                        ..
                    },
                ..
            } => Box::new(ExpectCertificate {
                config: self.config,
                server_name: self.server_name,
                randoms: self.randoms,
                suite: self.suite,
                transcript: self.transcript,
                key_schedule: self.key_schedule,
                client_auth: None,
            })
            .handle(cx, m),
            MessagePayload::Handshake {
                parsed:
                    HandshakeMessagePayload {
                        payload: HandshakePayload::CertificateRequestTls13(..),
                        ..
                    },
                ..
            } => Box::new(ExpectCertificateRequest {
                config: self.config,
                server_name: self.server_name,
                randoms: self.randoms,
                suite: self.suite,
                transcript: self.transcript,
                key_schedule: self.key_schedule,
            })
            .handle(cx, m),
            payload => Err(inappropriate_handshake_message(
                &payload,
                &[ContentType::Handshake],
                &[
                    HandshakeType::Certificate,
                    HandshakeType::CertificateRequest,
                ],
            )),
        }
    }

    fn into_owned(self: Box<Self>) -> hs::NextState<'static> {
        self
    }
}

// TLS1.3 version of CertificateRequest handling.  We then move to expecting the server
// Certificate. Unfortunately the CertificateRequest type changed in an annoying way
// in TLS1.3.
struct ExpectCertificateRequest {
    config: Arc<ClientConfig>,
    server_name: ServerName<'static>,
    randoms: ConnectionRandoms,
    suite: &'static Tls13CipherSuite,
    transcript: HandshakeHash,
    key_schedule: KeyScheduleHandshake,
}

impl State<ClientConnectionData> for ExpectCertificateRequest {
    fn handle<'m>(
        mut self: Box<Self>,
        cx: &mut ClientContext<'_>,
        m: Message<'m>,
    ) -> hs::NextStateOrError<'m>
    where
        Self: 'm,
    {
        let certreq = &require_handshake_msg!(
            m,
            HandshakeType::CertificateRequest,
            HandshakePayload::CertificateRequestTls13
        )?;
        self.transcript.add_message(&m);
        debug!("Got CertificateRequest {:?}", certreq);

        // Fortunately the problems here in TLS1.2 and prior are corrected in
        // TLS1.3.

        // Must be empty during handshake.
        if !certreq.context.0.is_empty() {
            warn!("Server sent non-empty certreq context");
            return Err(cx.common.send_fatal_alert(
                AlertDescription::DecodeError,
                InvalidMessage::InvalidCertRequest,
            ));
        }

        let no_sigschemes = Vec::new();
        let compat_sigschemes = certreq
            .sigalgs_extension()
            .unwrap_or(&no_sigschemes)
            .iter()
            .cloned()
            .filter(SignatureScheme::supported_in_tls13)
            .collect::<Vec<SignatureScheme>>();

        if compat_sigschemes.is_empty() {
            return Err(cx.common.send_fatal_alert(
                AlertDescription::HandshakeFailure,
                PeerIncompatible::NoCertificateRequestSignatureSchemesInCommon,
            ));
        }

        let client_auth = ClientAuthDetails::resolve(
            self.config
                .client_auth_cert_resolver
                .as_ref(),
            certreq.authorities_extension(),
            &compat_sigschemes,
            Some(certreq.context.0.clone()),
        );

        Ok(Box::new(ExpectCertificate {
            config: self.config,
            server_name: self.server_name,
            randoms: self.randoms,
            suite: self.suite,
            transcript: self.transcript,
            key_schedule: self.key_schedule,
            client_auth: Some(client_auth),
        }))
    }

    fn into_owned(self: Box<Self>) -> hs::NextState<'static> {
        self
    }
}

struct ExpectCertificate {
    config: Arc<ClientConfig>,
    server_name: ServerName<'static>,
    randoms: ConnectionRandoms,
    suite: &'static Tls13CipherSuite,
    transcript: HandshakeHash,
    key_schedule: KeyScheduleHandshake,
    client_auth: Option<ClientAuthDetails>,
}

impl State<ClientConnectionData> for ExpectCertificate {
    fn handle<'m>(
        mut self: Box<Self>,
        cx: &mut ClientContext<'_>,
        m: Message<'m>,
    ) -> hs::NextStateOrError<'m>
    where
        Self: 'm,
    {
        self.transcript.add_message(&m);
        let cert_chain = require_handshake_msg_move!(
            m,
            HandshakeType::Certificate,
            HandshakePayload::CertificateTls13
        )?;

        // This is only non-empty for client auth.
        if !cert_chain.context.0.is_empty() {
            return Err(cx.common.send_fatal_alert(
                AlertDescription::DecodeError,
                InvalidMessage::InvalidCertRequest,
            ));
        }

        if cert_chain.any_entry_has_duplicate_extension()
            || cert_chain.any_entry_has_unknown_extension()
        {
            return Err(cx.common.send_fatal_alert(
                AlertDescription::UnsupportedExtension,
                PeerMisbehaved::BadCertChainExtensions,
            ));
        }
        let end_entity_ocsp = cert_chain.end_entity_ocsp();
        let server_cert = ServerCertDetails::new(cert_chain.convert(), end_entity_ocsp);

        Ok(Box::new(ExpectCertificateVerify {
            config: self.config,
            server_name: self.server_name,
            randoms: self.randoms,
            suite: self.suite,
            transcript: self.transcript,
            key_schedule: self.key_schedule,
            server_cert,
            client_auth: self.client_auth,
        }))
    }

    fn into_owned(self: Box<Self>) -> hs::NextState<'static> {
        self
    }
}

// --- TLS1.3 CertificateVerify ---
struct ExpectCertificateVerify<'a> {
    config: Arc<ClientConfig>,
    server_name: ServerName<'static>,
    randoms: ConnectionRandoms,
    suite: &'static Tls13CipherSuite,
    transcript: HandshakeHash,
    key_schedule: KeyScheduleHandshake,
    server_cert: ServerCertDetails<'a>,
    client_auth: Option<ClientAuthDetails>,
}

impl State<ClientConnectionData> for ExpectCertificateVerify<'_> {
    fn handle<'m>(
        mut self: Box<Self>,
        cx: &mut ClientContext<'_>,
        m: Message<'m>,
    ) -> hs::NextStateOrError<'m>
    where
        Self: 'm,
    {
        let cert_verify = require_handshake_msg!(
            m,
            HandshakeType::CertificateVerify,
            HandshakePayload::CertificateVerify
        )?;

        trace!("Server cert is {:?}", self.server_cert.cert_chain);

        // 1. Verify the certificate chain.
        let (end_entity, intermediates) = self
            .server_cert
            .cert_chain
            .split_first()
            .ok_or(Error::NoCertificatesPresented)?;
        let cert_verified = self
            .config
            .verifier
            .verify_server_cert(
                end_entity,
                intermediates,
                &self.server_name,
                &self.server_cert.ocsp_response,
                UnixTime::now(),
            )
            .map_err(|err| {
                cx.common
                    .send_cert_verify_error_alert(err)
            })?;

        // 2. Verify their signature on the handshake.
        let handshake_hash = self.transcript.current_hash();
        let sig_verified = self
            .config
            .verifier
            .verify_tls13_signature(
                &construct_server_verify_message(&handshake_hash),
                &self.server_cert.cert_chain[0],
                cert_verify,
            )
            .map_err(|err| {
                cx.common
                    .send_cert_verify_error_alert(err)
            })?;

        cx.common.peer_certificates = Some(self.server_cert.cert_chain.into_owned());
        self.transcript.add_message(&m);

        Ok(Box::new(ExpectFinished {
            config: self.config,
            server_name: self.server_name,
            randoms: self.randoms,
            suite: self.suite,
            transcript: self.transcript,
            key_schedule: self.key_schedule,
            client_auth: self.client_auth,
            cert_verified,
            sig_verified,
        }))
    }

    fn into_owned(self: Box<Self>) -> hs::NextState<'static> {
        Box::new(ExpectCertificateVerify {
            config: self.config,
            server_name: self.server_name,
            randoms: self.randoms,
            suite: self.suite,
            transcript: self.transcript,
            key_schedule: self.key_schedule,
            server_cert: self.server_cert.into_owned(),
            client_auth: self.client_auth,
        })
    }
}

fn emit_certificate_tls13(
    transcript: &mut HandshakeHash,
    certkey: Option<&CertifiedKey>,
    auth_context: Option<Vec<u8>>,
    common: &mut CommonState,
) {
    let context = auth_context.unwrap_or_default();

    let mut cert_payload = CertificatePayloadTls13 {
        context: PayloadU8::new(context),
        entries: Vec::new(),
    };

    if let Some(certkey) = certkey {
        for cert in &certkey.cert {
            cert_payload
                .entries
                .push(CertificateEntry::new(cert.clone()));
        }
    }

    let m = Message {
        version: ProtocolVersion::TLSv1_3,
        payload: MessagePayload::handshake(HandshakeMessagePayload {
            typ: HandshakeType::Certificate,
            payload: HandshakePayload::CertificateTls13(cert_payload),
        }),
    };
    transcript.add_message(&m);
    common.send_msg(m, true);
}

fn emit_certverify_tls13(
    transcript: &mut HandshakeHash,
    signer: &dyn Signer,
    common: &mut CommonState,
) -> Result<(), Error> {
    let message = construct_client_verify_message(&transcript.current_hash());

    let scheme = signer.scheme();
    let sig = signer.sign(&message)?;
    let dss = DigitallySignedStruct::new(scheme, sig);

    let m = Message {
        version: ProtocolVersion::TLSv1_3,
        payload: MessagePayload::handshake(HandshakeMessagePayload {
            typ: HandshakeType::CertificateVerify,
            payload: HandshakePayload::CertificateVerify(dss),
        }),
    };

    transcript.add_message(&m);
    common.send_msg(m, true);
    Ok(())
}

fn emit_finished_tls13(
    transcript: &mut HandshakeHash,
    verify_data: &crypto::hmac::Tag,
    common: &mut CommonState,
) {
    let verify_data_payload = Payload::new(verify_data.as_ref());

    let m = Message {
        version: ProtocolVersion::TLSv1_3,
        payload: MessagePayload::handshake(HandshakeMessagePayload {
            typ: HandshakeType::Finished,
            payload: HandshakePayload::Finished(verify_data_payload),
        }),
    };

    transcript.add_message(&m);
    common.send_msg(m, true);
}

fn emit_end_of_early_data_tls13(transcript: &mut HandshakeHash, common: &mut CommonState) {
    if common.is_quic() {
        return;
    }

    let m = Message {
        version: ProtocolVersion::TLSv1_3,
        payload: MessagePayload::handshake(HandshakeMessagePayload {
            typ: HandshakeType::EndOfEarlyData,
            payload: HandshakePayload::EndOfEarlyData,
        }),
    };

    transcript.add_message(&m);
    common.send_msg(m, true);
}

struct ExpectFinished {
    config: Arc<ClientConfig>,
    server_name: ServerName<'static>,
    randoms: ConnectionRandoms,
    suite: &'static Tls13CipherSuite,
    transcript: HandshakeHash,
    key_schedule: KeyScheduleHandshake,
    client_auth: Option<ClientAuthDetails>,
    cert_verified: verify::ServerCertVerified,
    sig_verified: verify::HandshakeSignatureValid,
}

impl State<ClientConnectionData> for ExpectFinished {
    fn handle<'m>(
        self: Box<Self>,
        cx: &mut ClientContext<'_>,
        m: Message<'m>,
    ) -> hs::NextStateOrError<'m>
    where
        Self: 'm,
    {
        let mut st = *self;
        let finished =
            require_handshake_msg!(m, HandshakeType::Finished, HandshakePayload::Finished)?;

        let handshake_hash = st.transcript.current_hash();
        let expect_verify_data = st
            .key_schedule
            .sign_server_finish(&handshake_hash);

        let fin = match ConstantTimeEq::ct_eq(expect_verify_data.as_ref(), finished.bytes()).into()
        {
            true => verify::FinishedMessageVerified::assertion(),
            false => {
                return Err(cx
                    .common
                    .send_fatal_alert(AlertDescription::DecryptError, Error::DecryptError));
            }
        };

        st.transcript.add_message(&m);

        let hash_after_handshake = st.transcript.current_hash();
        /* The EndOfEarlyData message to server is still encrypted with early data keys,
         * but appears in the transcript after the server Finished. */
        if cx.common.early_traffic {
            emit_end_of_early_data_tls13(&mut st.transcript, cx.common);
            cx.common.early_traffic = false;
            cx.data.early_data.finished();
            st.key_schedule
                .set_handshake_encrypter(cx.common);
        }

        /* Send our authentication/finished messages.  These are still encrypted
         * with our handshake keys. */
        if let Some(client_auth) = st.client_auth {
            match client_auth {
                ClientAuthDetails::Empty {
                    auth_context_tls13: auth_context,
                } => {
                    emit_certificate_tls13(&mut st.transcript, None, auth_context, cx.common);
                }
                ClientAuthDetails::Verify {
                    certkey,
                    signer,
                    auth_context_tls13: auth_context,
                } => {
                    emit_certificate_tls13(
                        &mut st.transcript,
                        Some(&certkey),
                        auth_context,
                        cx.common,
                    );
                    emit_certverify_tls13(&mut st.transcript, signer.as_ref(), cx.common)?;
                }
            }
        }

        let (key_schedule_pre_finished, verify_data) = st
            .key_schedule
            .into_pre_finished_client_traffic(
                hash_after_handshake,
                st.transcript.current_hash(),
                &*st.config.key_log,
                &st.randoms.client,
            );

        emit_finished_tls13(&mut st.transcript, &verify_data, cx.common);

        /* We're now sure this server supports TLS1.3.  But if we run out of TLS1.3 tickets
         * when connecting to it again, we definitely don't want to attempt a TLS1.2 resumption. */
        st.config
            .resumption
            .store
            .remove_tls12_session(&st.server_name);

        /* Now move to our application traffic keys. */
        cx.common.check_aligned_handshake()?;
        let key_schedule_traffic = key_schedule_pre_finished.into_traffic(cx.common);
        cx.common
            .start_traffic(&mut cx.sendable_plaintext);

        let st = ExpectTraffic {
            session_storage: Arc::clone(&st.config.resumption.store),
            server_name: st.server_name,
            suite: st.suite,
            transcript: st.transcript,
            key_schedule: key_schedule_traffic,
            _cert_verified: st.cert_verified,
            _sig_verified: st.sig_verified,
            _fin_verified: fin,
        };

        Ok(match cx.common.is_quic() {
            true => Box::new(ExpectQuicTraffic(st)),
            false => Box::new(st),
        })
    }

    fn into_owned(self: Box<Self>) -> hs::NextState<'static> {
        self
    }
}

// -- Traffic transit state (TLS1.3) --
// In this state we can be sent tickets, key updates,
// and application data.
struct ExpectTraffic {
    session_storage: Arc<dyn ClientSessionStore>,
    server_name: ServerName<'static>,
    suite: &'static Tls13CipherSuite,
    transcript: HandshakeHash,
    key_schedule: KeyScheduleTraffic,
    _cert_verified: verify::ServerCertVerified,
    _sig_verified: verify::HandshakeSignatureValid,
    _fin_verified: verify::FinishedMessageVerified,
}

impl ExpectTraffic {
    fn handle_new_ticket_tls13(
        &mut self,
        cx: &mut ClientContext<'_>,
        nst: &NewSessionTicketPayloadTls13,
    ) -> Result<(), Error> {
        if nst.has_duplicate_extension() {
            return Err(cx.common.send_fatal_alert(
                AlertDescription::IllegalParameter,
                PeerMisbehaved::DuplicateNewSessionTicketExtensions,
            ));
        }

        let handshake_hash = self.transcript.current_hash();
        let secret = self
            .key_schedule
            .resumption_master_secret_and_derive_ticket_psk(&handshake_hash, &nst.nonce.0);

        #[allow(unused_mut)]
        let mut value = persist::Tls13ClientSessionValue::new(
            self.suite,
            nst.ticket.0.clone(),
            secret.as_ref(),
            cx.common
                .peer_certificates
                .clone()
                .unwrap_or_default(),
            UnixTime::now(),
            nst.lifetime,
            nst.age_add,
            nst.max_early_data_size()
                .unwrap_or_default(),
        );

        if cx.common.is_quic() {
            if let Some(sz) = nst.max_early_data_size() {
                if sz != 0 && sz != 0xffff_ffff {
                    return Err(PeerMisbehaved::InvalidMaxEarlyDataSize.into());
                }
            }

            if let Some(ref quic_params) = &cx.common.quic.params {
                value.set_quic_params(quic_params);
            }
        }

        self.session_storage
            .insert_tls13_ticket(self.server_name.clone(), value);
        Ok(())
    }

    fn handle_key_update(
        &mut self,
        common: &mut CommonState,
        key_update_request: &KeyUpdateRequest,
    ) -> Result<(), Error> {
        if let Protocol::Quic = common.protocol {
            return Err(common.send_fatal_alert(
                AlertDescription::UnexpectedMessage,
                PeerMisbehaved::KeyUpdateReceivedInQuicConnection,
            ));
        }

        // Mustn't be interleaved with other handshake messages.
        common.check_aligned_handshake()?;

        if common.should_update_key(key_update_request)? {
            self.key_schedule
                .update_encrypter_and_notify(common);
        }

        // Update our read-side keys.
        self.key_schedule
            .update_decrypter(common);
        Ok(())
    }
}

impl State<ClientConnectionData> for ExpectTraffic {
    fn handle<'m>(
        mut self: Box<Self>,
        cx: &mut ClientContext<'_>,
        m: Message<'m>,
    ) -> hs::NextStateOrError<'m>
    where
        Self: 'm,
    {
        match m.payload {
            MessagePayload::ApplicationData(payload) => cx
                .common
                .take_received_plaintext(payload),
            MessagePayload::Handshake {
                parsed:
                    HandshakeMessagePayload {
                        payload: HandshakePayload::NewSessionTicketTls13(ref new_ticket),
                        ..
                    },
                ..
            } => self.handle_new_ticket_tls13(cx, new_ticket)?,
            MessagePayload::Handshake {
                parsed:
                    HandshakeMessagePayload {
                        payload: HandshakePayload::KeyUpdate(ref key_update),
                        ..
                    },
                ..
            } => self.handle_key_update(cx.common, key_update)?,
            payload => {
                return Err(inappropriate_handshake_message(
                    &payload,
                    &[ContentType::ApplicationData, ContentType::Handshake],
                    &[HandshakeType::NewSessionTicket, HandshakeType::KeyUpdate],
                ));
            }
        }

        Ok(self)
    }

    fn export_keying_material(
        &self,
        output: &mut [u8],
        label: &[u8],
        context: Option<&[u8]>,
    ) -> Result<(), Error> {
        self.key_schedule
            .export_keying_material(output, label, context)
    }

    fn extract_secrets(&self) -> Result<PartiallyExtractedSecrets, Error> {
        self.key_schedule
            .extract_secrets(Side::Client)
    }

    fn into_owned(self: Box<Self>) -> hs::NextState<'static> {
        self
    }
}

struct ExpectQuicTraffic(ExpectTraffic);

impl State<ClientConnectionData> for ExpectQuicTraffic {
    fn handle<'m>(
        mut self: Box<Self>,
        cx: &mut ClientContext<'_>,
        m: Message<'m>,
    ) -> hs::NextStateOrError<'m>
    where
        Self: 'm,
    {
        let nst = require_handshake_msg!(
            m,
            HandshakeType::NewSessionTicket,
            HandshakePayload::NewSessionTicketTls13
        )?;
        self.0
            .handle_new_ticket_tls13(cx, nst)?;
        Ok(self)
    }

    fn export_keying_material(
        &self,
        output: &mut [u8],
        label: &[u8],
        context: Option<&[u8]>,
    ) -> Result<(), Error> {
        self.0
            .export_keying_material(output, label, context)
    }

    fn into_owned(self: Box<Self>) -> hs::NextState<'static> {
        self
    }
}