blob: 812d76999e9e1f94ffcb6eca949c8615b2e8b452 [file] [log] [blame]
use crate::session::{Session, SessionCommon};
use crate::keylog::{KeyLog, NoKeyLog};
use crate::suites::{SupportedCipherSuite, ALL_CIPHERSUITES};
use crate::msgs::enums::{ContentType, SignatureScheme};
use crate::msgs::enums::{AlertDescription, HandshakeType, ProtocolVersion};
use crate::msgs::handshake::ServerExtension;
use crate::msgs::message::Message;
use crate::error::TLSError;
use crate::sign;
use crate::verify;
use crate::key;
use crate::vecbuf::WriteV;
#[cfg(feature = "logging")]
use crate::log::trace;
use webpki;
use std::sync::Arc;
use std::io;
use std::fmt;
mod hs;
mod common;
pub mod handy;
/// A trait for the ability to store server session data.
/// The keys and values are opaque.
/// Both the keys and values should be treated as
/// **highly sensitive data**, containing enough key material
/// to break all security of the corresponding sessions.
/// Implementations can be lossy (in other words, forgetting
/// key/value pairs) without any negative security consequences.
/// However, note that `take` **must** reliably delete a returned
/// value. If it does not, there may be security consequences.
/// `put` and `take` are mutating operations; this isn't expressed
/// in the type system to allow implementations freedom in
/// how to achieve interior mutability. `Mutex` is a common
/// choice.
pub trait StoresServerSessions : Send + Sync {
/// Store session secrets encoded in `value` against `key`,
/// overwrites any existing value against `key`. Returns `true`
/// if the value was stored.
fn put(&self, key: Vec<u8>, value: Vec<u8>) -> bool;
/// Find a value with the given `key`. Return it, or None
/// if it doesn't exist.
fn get(&self, key: &[u8]) -> Option<Vec<u8>>;
/// Find a value with the given `key`. Return it and delete it;
/// or None if it doesn't exist.
fn take(&self, key: &[u8]) -> Option<Vec<u8>>;
/// A trait for the ability to encrypt and decrypt tickets.
pub trait ProducesTickets : Send + Sync {
/// Returns true if this implementation will encrypt/decrypt
/// tickets. Should return false if this is a dummy
/// implementation: the server will not send the SessionTicket
/// extension and will not call the other functions.
fn enabled(&self) -> bool;
/// Returns the lifetime in seconds of tickets produced now.
/// The lifetime is provided as a hint to clients that the
/// ticket will not be useful after the given time.
/// This lifetime must be implemented by key rolling and
/// erasure, *not* by storing a lifetime in the ticket.
/// The objective is to limit damage to forward secrecy caused
/// by tickets, not just limiting their lifetime.
fn get_lifetime(&self) -> u32;
/// Encrypt and authenticate `plain`, returning the resulting
/// ticket. Return None if `plain` cannot be encrypted for
/// some reason: an empty ticket will be sent and the connection
/// will continue.
fn encrypt(&self, plain: &[u8]) -> Option<Vec<u8>>;
/// Decrypt `cipher`, validating its authenticity protection
/// and recovering the plaintext. `cipher` is fully attacker
/// controlled, so this decryption must be side-channel free,
/// panic-proof, and otherwise bullet-proof. If the decryption
/// fails, return None.
fn decrypt(&self, cipher: &[u8]) -> Option<Vec<u8>>;
/// How to choose a certificate chain and signing key for use
/// in server authentication.
pub trait ResolvesServerCert : Send + Sync {
/// Choose a certificate chain and matching key given any server DNS
/// name provided via SNI, and signature schemes.
/// The certificate chain is returned as a vec of `Certificate`s,
/// the key is inside a `SigningKey`.
fn resolve(&self,
server_name: Option<webpki::DNSNameRef>,
sigschemes: &[SignatureScheme])
-> Option<sign::CertifiedKey>;
/// Common configuration for a set of server sessions.
/// Making one of these can be expensive, and should be
/// once per process rather than once per connection.
pub struct ServerConfig {
/// List of ciphersuites, in preference order.
pub ciphersuites: Vec<&'static SupportedCipherSuite>,
/// Ignore the client's ciphersuite order. Instead,
/// choose the top ciphersuite in the server list
/// which is supported by the client.
pub ignore_client_order: bool,
/// Our MTU. If None, we don't limit TLS message sizes.
pub mtu: Option<usize>,
/// How to store client sessions.
pub session_storage: Arc<StoresServerSessions + Send + Sync>,
/// How to produce tickets.
pub ticketer: Arc<ProducesTickets>,
/// How to choose a server cert and key.
pub cert_resolver: Arc<ResolvesServerCert>,
/// Protocol names we support, most preferred first.
/// If empty we don't do ALPN at all.
pub alpn_protocols: Vec<Vec<u8>>,
/// Supported protocol versions, in no particular order.
/// The default is all supported versions.
pub versions: Vec<ProtocolVersion>,
/// How to verify client certificates.
verifier: Arc<verify::ClientCertVerifier>,
/// How to output key material for debugging. The default
/// does nothing.
pub key_log: Arc<KeyLog>,
/// Amount of early data to accept; 0 to disable.
#[cfg(feature = "quic")] // TLS support unimplemented
pub max_early_data_size: u32,
impl ServerConfig {
/// Make a `ServerConfig` with a default set of ciphersuites,
/// no keys/certificates, and no ALPN protocols. Session resumption
/// is enabled by storing up to 256 recent sessions in memory. Tickets are
/// disabled.
/// Publicly-available web servers on the internet generally don't do client
/// authentication; for this use case, `client_cert_verifier` should be a
/// `NoClientAuth`. Otherwise, use `AllowAnyAuthenticatedClient` or another
/// implementation to enforce client authentication.
/// We don't provide a default for `client_cert_verifier` because the safest
/// default, requiring client authentication, requires additional
/// configuration that we cannot provide reasonable defaults for.
pub fn new(client_cert_verifier: Arc<verify::ClientCertVerifier>) -> ServerConfig {
ServerConfig {
ciphersuites: ALL_CIPHERSUITES.to_vec(),
ignore_client_order: false,
mtu: None,
session_storage: handy::ServerSessionMemoryCache::new(256),
ticketer: Arc::new(handy::NeverProducesTickets {}),
alpn_protocols: Vec::new(),
cert_resolver: Arc::new(handy::FailResolveChain {}),
versions: vec![ ProtocolVersion::TLSv1_3, ProtocolVersion::TLSv1_2 ],
verifier: client_cert_verifier,
key_log: Arc::new(NoKeyLog {}),
#[cfg(feature = "quic")]
max_early_data_size: 0,
/// We support a given TLS version if it's quoted in the configured
/// versions *and* at least one ciphersuite for this version is
/// also configured.
pub fn supports_version(&self, v: ProtocolVersion) -> bool {
self.versions.contains(&v) && self.ciphersuites.iter().any(|cs| cs.usable_for_version(v))
pub fn get_verifier(&self) -> &verify::ClientCertVerifier {
/// Sets the session persistence layer to `persist`.
pub fn set_persistence(&mut self, persist: Arc<StoresServerSessions + Send + Sync>) {
self.session_storage = persist;
/// Sets a single certificate chain and matching private key. This
/// certificate and key is used for all subsequent connections,
/// irrespective of things like SNI hostname.
/// Note that the end-entity certificate must have the
/// [Subject Alternative Name](
/// extension to describe, e.g., the valid DNS name. The `commonName` field is
/// disregarded.
/// `cert_chain` is a vector of DER-encoded certificates.
/// `key_der` is a DER-encoded RSA or ECDSA private key.
/// This function fails if `key_der` is invalid.
pub fn set_single_cert(&mut self,
cert_chain: Vec<key::Certificate>,
key_der: key::PrivateKey) -> Result<(), TLSError> {
let resolver = handy::AlwaysResolvesChain::new(cert_chain, &key_der)?;
self.cert_resolver = Arc::new(resolver);
/// Sets a single certificate chain, matching private key and OCSP
/// response. This certificate and key is used for all subsequent
/// connections, irrespective of things like SNI hostname.
/// `cert_chain` is a vector of DER-encoded certificates.
/// `key_der` is a DER-encoded RSA or ECDSA private key.
/// `ocsp` is a DER-encoded OCSP response. Ignored if zero length.
/// `scts` is an `SignedCertificateTimestampList` encoding (see RFC6962)
/// and is ignored if empty.
/// This function fails if `key_der` is invalid.
pub fn set_single_cert_with_ocsp_and_sct(&mut self,
cert_chain: Vec<key::Certificate>,
key_der: key::PrivateKey,
ocsp: Vec<u8>,
scts: Vec<u8>) -> Result<(), TLSError> {
let resolver = handy::AlwaysResolvesChain::new_with_extras(cert_chain,
self.cert_resolver = Arc::new(resolver);
/// Set the ALPN protocol list to the given protocol names.
/// Overwrites any existing configured protocols.
/// The first element in the `protocols` list is the most
/// preferred, the last is the least preferred.
pub fn set_protocols(&mut self, protocols: &[Vec<u8>]) {
pub struct ServerSessionImpl {
pub config: Arc<ServerConfig>,
pub common: SessionCommon,
sni: Option<webpki::DNSName>,
pub alpn_protocol: Option<Vec<u8>>,
pub quic_params: Option<Vec<u8>>,
pub error: Option<TLSError>,
pub state: Option<Box<hs::State + Send + Sync>>,
pub client_cert_chain: Option<Vec<key::Certificate>>,
impl fmt::Debug for ServerSessionImpl {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
impl ServerSessionImpl {
pub fn new(server_config: &Arc<ServerConfig>, extra_exts: Vec<ServerExtension>)
-> ServerSessionImpl {
let mut common = SessionCommon::new(server_config.mtu, false);
if server_config.verifier.offer_client_auth() {
ServerSessionImpl {
config: server_config.clone(),
sni: None,
alpn_protocol: None,
quic_params: None,
error: None,
state: Some(Box::new(hs::ExpectClientHello::new(extra_exts))),
client_cert_chain: None,
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.
// This also covers the handshake case, because we don't have
// readable plaintext before handshake has completed.
pub fn wants_write(&self) -> bool {
pub fn is_handshaking(&self) -> bool {
pub fn set_buffer_limit(&mut self, len: usize) {
pub fn process_msg(&mut self, mut msg: Message) -> Result<(), TLSError> {
// TLS1.3: drop CCS at any time during handshaking
if self.common.is_tls13()
&& msg.is_content_type(ContentType::ChangeCipherSpec)
&& self.is_handshaking() {
trace!("Dropping CCS");
return Ok(());
// Decrypt if demanded by current state.
if self.common.peer_encrypting {
let dm = self.common.decrypt_incoming(msg)?;
msg = dm;
// For handshake messages, we need to join them before parsing
// and processing.
if self.common.handshake_joiner.want_message(&msg) {
.ok_or_else(|| {
return self.process_new_handshake_messages();
// Now we can fully parse the message payload.
if msg.is_content_type(ContentType::Alert) {
return self.common.process_alert(msg);
pub fn process_new_handshake_messages(&mut self) -> Result<(), TLSError> {
while let Some(msg) = self.common.handshake_joiner.frames.pop_front() {
fn queue_unexpected_alert(&mut self) {
pub fn process_main_protocol(&mut self, msg: Message) -> Result<(), TLSError> {
if self.common.traffic && !self.common.is_tls13() &&
msg.is_handshake_type(HandshakeType::ClientHello) {
return Ok(());
let st = self.state.take().unwrap();
.map_err(|err| { self.queue_unexpected_alert(); err })?;
self.state = Some(st.handle(self, msg)?);
pub fn process_new_packets(&mut self) -> Result<(), TLSError> {
if let Some(ref err) = self.error {
return Err(err.clone());
if self.common.message_deframer.desynced {
return Err(TLSError::CorruptMessage);
while let Some(msg) = self.common.message_deframer.frames.pop_front() {
match self.process_msg(msg) {
Ok(_) => {}
Err(err) => {
self.error = Some(err.clone());
return Err(err);
pub fn get_peer_certificates(&self) -> Option<Vec<key::Certificate>> {
if self.client_cert_chain.is_none() {
return None;
let mut r = Vec::new();
for cert in self.client_cert_chain.as_ref().unwrap() {
pub fn get_alpn_protocol(&self) -> Option<&[u8]> {
self.alpn_protocol.as_ref().map(|s| s.as_ref())
pub fn get_protocol_version(&self) -> Option<ProtocolVersion> {
pub fn get_negotiated_ciphersuite(&self) -> Option<&'static SupportedCipherSuite> {
pub fn get_sni(&self)-> Option<&webpki::DNSName> {
pub fn set_sni(&mut self, value: webpki::DNSName) {
// The SNI hostname is immutable once set.
self.sni = Some(value)
/// This represents a single TLS server session.
/// Send TLS-protected data to the peer using the `io::Write` trait implementation.
/// Read data from the peer using the `io::Read` trait implementation.
pub struct ServerSession {
// We use the pimpl idiom to hide unimportant details.
pub(crate) imp: ServerSessionImpl,
impl ServerSession {
/// Make a new ServerSession. `config` controls how
/// we behave in the TLS protocol.
pub fn new(config: &Arc<ServerConfig>) -> ServerSession {
ServerSession { imp: ServerSessionImpl::new(config, vec![]) }
/// Retrieves the SNI hostname, if any, used to select the certificate and
/// private key.
/// This returns `None` until some time after the client's SNI extension
/// value is processed during the handshake. It will never be `None` when
/// the connection is ready to send or process application data, unless the
/// client does not support SNI.
/// This is useful for application protocols that need to enforce that the
/// SNI hostname matches an application layer protocol hostname. For
/// example, HTTP/1.1 servers commonly expect the `Host:` header field of
/// every request on a connection to match the hostname in the SNI extension
/// when the client provides the SNI extension.
/// The SNI hostname is also used to match sessions during session
/// resumption.
pub fn get_sni_hostname(&self)-> Option<&str> {
self.imp.get_sni().map(|s| s.as_ref().into())
impl Session for ServerSession {
fn read_tls(&mut self, rd: &mut io::Read) -> io::Result<usize> {
/// Writes TLS messages to `wr`.
fn write_tls(&mut self, wr: &mut io::Write) -> io::Result<usize> {
fn writev_tls(&mut self, wr: &mut WriteV) -> io::Result<usize> {
fn process_new_packets(&mut self) -> Result<(), TLSError> {
fn wants_read(&self) -> bool {
fn wants_write(&self) -> bool {
fn is_handshaking(&self) -> bool {
fn set_buffer_limit(&mut self, len: usize) {
fn send_close_notify(&mut self) {
fn get_peer_certificates(&self) -> Option<Vec<key::Certificate>> {
fn get_alpn_protocol(&self) -> Option<&[u8]> {
fn get_protocol_version(&self) -> Option<ProtocolVersion> {
fn export_keying_material(&self,
output: &mut [u8],
label: &[u8],
context: Option<&[u8]>) -> Result<(), TLSError> {
self.imp.common.export_keying_material(output, label, context)
fn get_negotiated_ciphersuite(&self) -> Option<&'static SupportedCipherSuite> {
impl io::Read for ServerSession {
/// Obtain plaintext data received from the peer over
/// this TLS connection.
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
impl io::Write for ServerSession {
/// Send the plaintext `buf` to the peer, encrypting
/// and authenticating it. Once this function succeeds
/// you should call `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. This buffer is of *unlimited size* so
/// writing much data before it can be sent will
/// cause excess memory usage.
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
fn flush(&mut self) -> io::Result<()> {