DNS/TLS deps are now optional, component now also uses ServerConnector

tokio-xmpp/src/starttls/mod.rs

@@ -0,0 +1,168 @@
+//! `starttls::ServerConfig` provides a `ServerConnector` for starttls connections
+
+use futures::{sink::SinkExt, stream::StreamExt};
+
+#[cfg(all(feature = "tls-rust", not(feature = "tls-native")))]
+use {
+    std::sync::Arc,
+    tokio_rustls::{
+        client::TlsStream,
+        rustls::{ClientConfig, OwnedTrustAnchor, RootCertStore, ServerName},
+        TlsConnector,
+    },
+    webpki_roots,
+};
+
+#[cfg(feature = "tls-native")]
+use {
+    native_tls::TlsConnector as NativeTlsConnector,
+    tokio_native_tls::{TlsConnector, TlsStream},
+};
+
+use sasl::common::ChannelBinding;
+use tokio::{
+    io::{AsyncRead, AsyncWrite},
+    net::TcpStream,
+};
+use xmpp_parsers::{ns, Element, Jid};
+
+use crate::{connect::ServerConnector, xmpp_codec::Packet};
+use crate::{connect::ServerConnectorError, xmpp_stream::XMPPStream};
+
+use self::error::Error;
+use self::happy_eyeballs::{connect_to_host, connect_with_srv};
+
+mod client;
+mod error;
+mod happy_eyeballs;
+
+/// StartTLS XMPP server connection configuration
+#[derive(Clone, Debug)]
+pub enum ServerConfig {
+    /// Use SRV record to find server host
+    UseSrv,
+    #[allow(unused)]
+    /// Manually define server host and port
+    Manual {
+        /// Server host name
+        host: String,
+        /// Server port
+        port: u16,
+    },
+}
+
+impl ServerConnectorError for Error {}
+
+impl ServerConnector for ServerConfig {
+    type Stream = TlsStream<TcpStream>;
+    type Error = Error;
+    async fn connect(&self, jid: &Jid, ns: &str) -> Result<XMPPStream<Self::Stream>, Error> {
+        // TCP connection
+        let tcp_stream = match self {
+            ServerConfig::UseSrv => {
+                connect_with_srv(jid.domain_str(), "_xmpp-client._tcp", 5222).await?
+            }
+            ServerConfig::Manual { host, port } => connect_to_host(host.as_str(), *port).await?,
+        };
+
+        // Unencryped XMPPStream
+        let xmpp_stream = XMPPStream::start(tcp_stream, jid.clone(), ns.to_owned()).await?;
+
+        if xmpp_stream.stream_features.can_starttls() {
+            // TlsStream
+            let tls_stream = starttls(xmpp_stream).await?;
+            // Encrypted XMPPStream
+            Ok(XMPPStream::start(tls_stream, jid.clone(), ns.to_owned()).await?)
+        } else {
+            return Err(crate::Error::Protocol(crate::ProtocolError::NoTls).into());
+        }
+    }
+
+    fn channel_binding(
+        #[allow(unused_variables)] stream: &Self::Stream,
+    ) -> Result<sasl::common::ChannelBinding, Error> {
+        #[cfg(feature = "tls-native")]
+        {
+            log::warn!("tls-native doesn’t support channel binding, please use tls-rust if you want this feature!");
+            Ok(ChannelBinding::None)
+        }
+        #[cfg(all(feature = "tls-rust", not(feature = "tls-native")))]
+        {
+            let (_, connection) = stream.get_ref();
+            Ok(match connection.protocol_version() {
+                // TODO: Add support for TLS 1.2 and earlier.
+                Some(tokio_rustls::rustls::ProtocolVersion::TLSv1_3) => {
+                    let data = vec![0u8; 32];
+                    let data = connection.export_keying_material(
+                        data,
+                        b"EXPORTER-Channel-Binding",
+                        None,
+                    )?;
+                    ChannelBinding::TlsExporter(data)
+                }
+                _ => ChannelBinding::None,
+            })
+        }
+    }
+}
+
+#[cfg(feature = "tls-native")]
+async fn get_tls_stream<S: AsyncRead + AsyncWrite + Unpin>(
+    xmpp_stream: XMPPStream<S>,
+) -> Result<TlsStream<S>, Error> {
+    let domain = xmpp_stream.jid.domain_str().to_owned();
+    let stream = xmpp_stream.into_inner();
+    let tls_stream = TlsConnector::from(NativeTlsConnector::builder().build().unwrap())
+        .connect(&domain, stream)
+        .await?;
+    Ok(tls_stream)
+}
+
+#[cfg(all(feature = "tls-rust", not(feature = "tls-native")))]
+async fn get_tls_stream<S: AsyncRead + AsyncWrite + Unpin>(
+    xmpp_stream: XMPPStream<S>,
+) -> Result<TlsStream<S>, Error> {
+    let domain = xmpp_stream.jid.domain_str().to_owned();
+    let domain = ServerName::try_from(domain.as_str())?;
+    let stream = xmpp_stream.into_inner();
+    let mut root_store = RootCertStore::empty();
+    root_store.add_trust_anchors(webpki_roots::TLS_SERVER_ROOTS.iter().map(|ta| {
+        OwnedTrustAnchor::from_subject_spki_name_constraints(
+            ta.subject,
+            ta.spki,
+            ta.name_constraints,
+        )
+    }));
+    let config = ClientConfig::builder()
+        .with_safe_defaults()
+        .with_root_certificates(root_store)
+        .with_no_client_auth();
+    let tls_stream = TlsConnector::from(Arc::new(config))
+        .connect(domain, stream)
+        .await
+        .map_err(|e| Error::from(crate::Error::Io(e)))?;
+    Ok(tls_stream)
+}
+
+/// Performs `<starttls/>` on an XMPPStream and returns a binary
+/// TlsStream.
+pub async fn starttls<S: AsyncRead + AsyncWrite + Unpin>(
+    mut xmpp_stream: XMPPStream<S>,
+) -> Result<TlsStream<S>, Error> {
+    let nonza = Element::builder("starttls", ns::TLS).build();
+    let packet = Packet::Stanza(nonza);
+    xmpp_stream.send(packet).await?;
+
+    loop {
+        match xmpp_stream.next().await {
+            Some(Ok(Packet::Stanza(ref stanza))) if stanza.name() == "proceed" => break,
+            Some(Ok(Packet::Text(_))) => {}
+            Some(Err(e)) => return Err(e.into()),
+            _ => {
+                return Err(crate::Error::Protocol(crate::ProtocolError::NoTls).into());
+            }
+        }
+    }
+
+    get_tls_stream(xmpp_stream).await
+}