Initial commit

src/handshake/mod.rs

@@ -0,0 +1,242 @@
+use crate::ProtocolError;
+use crate::config::TlsCipherSuite;
+use crate::handshake::certificate::CertificateRef;
+use crate::handshake::certificate_request::CertificateRequestRef;
+use crate::handshake::certificate_verify::{HandshakeVerify, HandshakeVerifyRef};
+use crate::handshake::client_hello::ClientHello;
+use crate::handshake::encrypted_extensions::EncryptedExtensions;
+use crate::handshake::finished::Finished;
+use crate::handshake::new_session_ticket::NewSessionTicket;
+use crate::handshake::server_hello::ServerHello;
+use crate::key_schedule::HashOutputSize;
+use crate::parse_buffer::{ParseBuffer, ParseError};
+use crate::{buffer::CryptoBuffer, key_schedule::WriteKeySchedule};
+use core::fmt::{Debug, Formatter};
+use sha2::Digest;
+
+pub mod binder;
+pub mod certificate;
+pub mod certificate_request;
+pub mod certificate_verify;
+pub mod client_hello;
+pub mod encrypted_extensions;
+pub mod finished;
+pub mod new_session_ticket;
+pub mod server_hello;
+
+// TLS legacy_record_version field — always 0x0303 for TLS 1.3 compatibility (RFC 8446 §5.1)
+const LEGACY_VERSION: u16 = 0x0303;
+
+type Random = [u8; 32];
+
+#[derive(Debug, Copy, Clone)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub enum HandshakeType {
+    ClientHello = 1,
+    ServerHello = 2,
+    NewSessionTicket = 4,
+    EndOfEarlyData = 5,
+    EncryptedExtensions = 8,
+    Certificate = 11,
+    CertificateRequest = 13,
+    HandshakeVerify = 15,
+    Finished = 20,
+    KeyUpdate = 24,
+    MessageHash = 254,
+}
+
+impl HandshakeType {
+    pub fn parse(buf: &mut ParseBuffer) -> Result<Self, ParseError> {
+        match buf.read_u8()? {
+            1 => Ok(HandshakeType::ClientHello),
+            2 => Ok(HandshakeType::ServerHello),
+            4 => Ok(HandshakeType::NewSessionTicket),
+            5 => Ok(HandshakeType::EndOfEarlyData),
+            8 => Ok(HandshakeType::EncryptedExtensions),
+            11 => Ok(HandshakeType::Certificate),
+            13 => Ok(HandshakeType::CertificateRequest),
+            15 => Ok(HandshakeType::HandshakeVerify),
+            20 => Ok(HandshakeType::Finished),
+            24 => Ok(HandshakeType::KeyUpdate),
+            254 => Ok(HandshakeType::MessageHash),
+            _ => Err(ParseError::InvalidData),
+        }
+    }
+}
+
+#[allow(clippy::large_enum_variant)]
+pub enum ClientHandshake<'config, 'a, CipherSuite>
+where
+    CipherSuite: TlsCipherSuite,
+{
+    ClientCert(CertificateRef<'a>),
+    ClientCertVerify(HandshakeVerify),
+    ClientHello(ClientHello<'config, CipherSuite>),
+    Finished(Finished<HashOutputSize<CipherSuite>>),
+}
+
+impl<CipherSuite> ClientHandshake<'_, '_, CipherSuite>
+where
+    CipherSuite: TlsCipherSuite,
+{
+    fn handshake_type(&self) -> HandshakeType {
+        match self {
+            ClientHandshake::ClientHello(_) => HandshakeType::ClientHello,
+            ClientHandshake::Finished(_) => HandshakeType::Finished,
+            ClientHandshake::ClientCert(_) => HandshakeType::Certificate,
+            ClientHandshake::ClientCertVerify(_) => HandshakeType::HandshakeVerify,
+        }
+    }
+
+    fn encode_inner(&self, buf: &mut CryptoBuffer<'_>) -> Result<(), ProtocolError> {
+        match self {
+            ClientHandshake::ClientHello(inner) => inner.encode(buf),
+            ClientHandshake::Finished(inner) => inner.encode(buf),
+            ClientHandshake::ClientCert(inner) => inner.encode(buf),
+            ClientHandshake::ClientCertVerify(inner) => inner.encode(buf),
+        }
+    }
+
+    pub(crate) fn encode(&self, buf: &mut CryptoBuffer<'_>) -> Result<(), ProtocolError> {
+        buf.push(self.handshake_type() as u8)
+            .map_err(|_| ProtocolError::EncodeError)?;
+
+        // Handshake message body is preceded by a 3-byte (u24) length (RFC 8446 §4)
+        buf.with_u24_length(|buf| self.encode_inner(buf))
+    }
+
+    pub fn finalize(
+        &self,
+        buf: &mut CryptoBuffer,
+        transcript: &mut CipherSuite::Hash,
+        write_key_schedule: &mut WriteKeySchedule<CipherSuite>,
+    ) -> Result<(), ProtocolError> {
+        let enc_buf = buf.as_mut_slice();
+        if let ClientHandshake::ClientHello(hello) = self {
+            hello.finalize(enc_buf, transcript, write_key_schedule)
+        } else {
+            transcript.update(enc_buf);
+            Ok(())
+        }
+    }
+
+    pub fn finalize_encrypted(buf: &mut CryptoBuffer, transcript: &mut CipherSuite::Hash) {
+        let enc_buf = buf.as_slice();
+        let end = enc_buf.len();
+        transcript.update(&enc_buf[0..end]);
+    }
+}
+
+#[allow(clippy::large_enum_variant)]
+pub enum ServerHandshake<'a, CipherSuite: TlsCipherSuite> {
+    ServerHello(ServerHello<'a>),
+    EncryptedExtensions(EncryptedExtensions<'a>),
+    NewSessionTicket(NewSessionTicket<'a>),
+    Certificate(CertificateRef<'a>),
+    CertificateRequest(CertificateRequestRef<'a>),
+    HandshakeVerify(HandshakeVerifyRef<'a>),
+    Finished(Finished<HashOutputSize<CipherSuite>>),
+}
+
+impl<CipherSuite: TlsCipherSuite> ServerHandshake<'_, CipherSuite> {
+    #[allow(dead_code)]
+    pub fn handshake_type(&self) -> HandshakeType {
+        match self {
+            ServerHandshake::ServerHello(_) => HandshakeType::ServerHello,
+            ServerHandshake::EncryptedExtensions(_) => HandshakeType::EncryptedExtensions,
+            ServerHandshake::NewSessionTicket(_) => HandshakeType::NewSessionTicket,
+            ServerHandshake::Certificate(_) => HandshakeType::Certificate,
+            ServerHandshake::CertificateRequest(_) => HandshakeType::CertificateRequest,
+            ServerHandshake::HandshakeVerify(_) => HandshakeType::HandshakeVerify,
+            ServerHandshake::Finished(_) => HandshakeType::Finished,
+        }
+    }
+}
+
+impl<CipherSuite: TlsCipherSuite> Debug for ServerHandshake<'_, CipherSuite> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
+        match self {
+            ServerHandshake::ServerHello(inner) => Debug::fmt(inner, f),
+            ServerHandshake::EncryptedExtensions(inner) => Debug::fmt(inner, f),
+            ServerHandshake::Certificate(inner) => Debug::fmt(inner, f),
+            ServerHandshake::CertificateRequest(inner) => Debug::fmt(inner, f),
+            ServerHandshake::HandshakeVerify(inner) => Debug::fmt(inner, f),
+            ServerHandshake::Finished(inner) => Debug::fmt(inner, f),
+            ServerHandshake::NewSessionTicket(inner) => Debug::fmt(inner, f),
+        }
+    }
+}
+
+#[cfg(feature = "defmt")]
+impl<'a, CipherSuite: TlsCipherSuite> defmt::Format for ServerHandshake<'a, CipherSuite> {
+    fn format(&self, f: defmt::Formatter<'_>) {
+        match self {
+            ServerHandshake::ServerHello(inner) => defmt::write!(f, "{}", inner),
+            ServerHandshake::EncryptedExtensions(inner) => defmt::write!(f, "{}", inner),
+            ServerHandshake::Certificate(inner) => defmt::write!(f, "{}", inner),
+            ServerHandshake::CertificateRequest(inner) => defmt::write!(f, "{}", inner),
+            ServerHandshake::HandshakeVerify(inner) => defmt::write!(f, "{}", inner),
+            ServerHandshake::Finished(inner) => defmt::write!(f, "{}", inner),
+            ServerHandshake::NewSessionTicket(inner) => defmt::write!(f, "{}", inner),
+        }
+    }
+}
+
+impl<'a, CipherSuite: TlsCipherSuite> ServerHandshake<'a, CipherSuite> {
+    pub fn read(
+        buf: &mut ParseBuffer<'a>,
+        digest: &mut CipherSuite::Hash,
+    ) -> Result<Self, ProtocolError> {
+        let handshake_start = buf.offset();
+        let mut handshake = Self::parse(buf)?;
+        let handshake_end = buf.offset();
+
+        // Capture the current transcript hash into Finished before we update it with this message
+        if let ServerHandshake::Finished(finished) = &mut handshake {
+            finished.hash.replace(digest.clone().finalize());
+        }
+
+        digest.update(&buf.as_slice()[handshake_start..handshake_end]);
+
+        Ok(handshake)
+    }
+
+    fn parse(buf: &mut ParseBuffer<'a>) -> Result<Self, ProtocolError> {
+        let handshake_type =
+            HandshakeType::parse(buf).map_err(|_| ProtocolError::InvalidHandshake)?;
+
+        trace!("handshake = {:?}", handshake_type);
+
+        let content_len = buf
+            .read_u24()
+            .map_err(|_| ProtocolError::InvalidHandshake)?;
+
+        let handshake = match handshake_type {
+            HandshakeType::ServerHello => ServerHandshake::ServerHello(ServerHello::parse(buf)?),
+            HandshakeType::NewSessionTicket => {
+                ServerHandshake::NewSessionTicket(NewSessionTicket::parse(buf)?)
+            }
+            HandshakeType::EncryptedExtensions => {
+                ServerHandshake::EncryptedExtensions(EncryptedExtensions::parse(buf)?)
+            }
+            HandshakeType::Certificate => ServerHandshake::Certificate(CertificateRef::parse(buf)?),
+
+            HandshakeType::CertificateRequest => {
+                ServerHandshake::CertificateRequest(CertificateRequestRef::parse(buf)?)
+            }
+
+            HandshakeType::HandshakeVerify => {
+                ServerHandshake::HandshakeVerify(HandshakeVerifyRef::parse(buf)?)
+            }
+            HandshakeType::Finished => {
+                ServerHandshake::Finished(Finished::parse(buf, content_len)?)
+            }
+            t => {
+                warn!("Unimplemented handshake type: {:?}", t);
+                return Err(ProtocolError::Unimplemented);
+            }
+        };
+
+        Ok(handshake)
+    }
+}