[noise][stack] fixup initiator to increase security and allow it to initialize HandshakeStates even when we dont know the other parties public key prior to initialization

quicktap/src/device/mod.rs

@@ -1,2 +1,37 @@
 //! A high-level implementation of the `WireGuard` protocol; does everything the kernel module does except for interfacing with the networking interfaces.
 //! Use the appropriate glue layer in `quicktap::drivers` to provide the tun/tap interface, and the mechanism in `quicktap::drivers::udp_listener` for working with the `UdpSocket`.
+
+use std::collections::HashMap;
+use x25519_dalek::PublicKey;
+use crate::noise::handshake::HandshakeState;
+
+#[derive(Default)]
+/// A high-level struct for the configuration of a `WireGuard` device. This is the equivalent of `[Interface]` in wg-quick.
+pub struct QTInterface<'a> {
+    peers: HashMap<PublicKey, QTPeer<'a>>
+}
+impl<'a> QTInterface<'a> {
+    /// Create a new, blank `QTInterface` with no configuration
+    pub fn new() -> Self {
+        QTInterface {
+            peers: HashMap::default(),
+        }
+    }
+}
+
+/// A high-level struct for the current state with another peer. This is the equivalent of `[Peer]` in wg-quick, with additional tunneling information added.
+pub struct QTPeer<'a> {
+    handshake: Option<HandshakeState<'a>>,
+    handshake_in_flight: Option<HandshakeState<'a>>,
+    public_key: PublicKey
+}
+impl<'a> QTPeer<'a> {
+    /// Create a new, blank `QTPeer` with no configuration
+    pub fn new(key: PublicKey) -> Self {
+        QTPeer {
+            handshake: None,
+            handshake_in_flight: None,
+            public_key: key,
+        }
+    }
+}

quicktap/src/drivers/udp_listener.rs

@@ -3,8 +3,9 @@
 use std::error::Error;
 use std::io;
 use std::net::UdpSocket;
+use crate::device::QTInterface;
 use crate::drivers::error::DriverError;
-use crate::stack::entry::PacketEntryStage;
+use crate::stack::entry_udp::UDPPacketEntryStage;
 use crate::stack::PacketProcessingStage;
 
 /// The maximum amount of bytes that can be taken up by a Handshake Initiation packet.
@@ -29,7 +30,7 @@ pub enum SocketRoundResult {
 /// If you're writing a frontend, this is probably not what you want. Use `qtap_socket_rounds_until_empty` instead.
 /// # Errors
 /// This function will error if a socket read fails or the processing of the packet fails. See `PacketEntryStage::process_packet()` for more details on packet processing.
-pub fn qtap_socket_round(socket: &mut UdpSocket) -> Result<(), SocketRoundResult> {
+pub fn qtap_socket_round(socket: &mut UdpSocket, interface: &QTInterface) -> Result<(), SocketRoundResult> {
     let mut packet_id = [0u8; 1];
     match socket.peek(&mut packet_id) {
         Ok(_) => (),
@@ -54,7 +55,7 @@ pub fn qtap_socket_round(socket: &mut UdpSocket) -> Result<(), SocketRoundResult
 
     let packet = packet_buf[..read_bytes].to_vec();
 
-    match PacketEntryStage::process_packet(packet, &from) {
+    match UDPPacketEntryStage::process_packet(packet, &from, interface) {
         Ok(_) => Ok(()),
         Err(e) => Err(SocketRoundResult::GenericAnyError(e))
     }
@@ -65,9 +66,9 @@ pub fn qtap_socket_round(socket: &mut UdpSocket) -> Result<(), SocketRoundResult
 /// If you only want to run one update, use `qtap_socket_round` instead.
 /// # Errors
 /// See `qtap_socket_round`
-pub fn qtap_socket_rounds_until_empty(socket: &mut UdpSocket) -> Result<(), Box<dyn Error>> {
+pub fn qtap_socket_rounds_until_empty(socket: &mut UdpSocket, interface: &QTInterface) -> Result<(), Box<dyn Error>> {
     loop {
-        match qtap_socket_round(socket) {
+        match qtap_socket_round(socket, interface) {
             Ok(_) => (),
             Err(e) => {
                 match e {

quicktap/src/noise/handshake/initiator.rs

@@ -117,7 +117,7 @@ pub fn generate_handshake_init(session: &mut HandshakeState) -> Result<[u8; 148]
     Ok(msg.to_bytes(session))
 }
 
-/// Parse a handshake initiator packet and encrypt it using the given session state, updating the session state with decrypted and authenticated values
+/// Parse a handshake initiator packet and decrypt it using the given session state, updating the session state with decrypted and authenticated values
 /// # Errors
 /// This function will error if decryption was unsuccessful
 /// # Panics
@@ -125,7 +125,6 @@ pub fn generate_handshake_init(session: &mut HandshakeState) -> Result<[u8; 148]
 #[allow(clippy::module_name_repetitions)]
 #[allow(clippy::unwrap_used)] // Only used for type conversions in known safe ways
 pub fn parse_handshake_init(session: &mut HandshakeState, packet: [u8; 148]) -> Result<(), NoiseError> {
-    let s_pub_i = session.s_pub_them;
     let s_pub_r = PublicKey::from(session.s_priv_me);
 
     let msg = HandshakeInitiatorRaw::from_bytes(packet);
@@ -151,14 +150,14 @@ pub fn parse_handshake_init(session: &mut HandshakeState, packet: [u8; 148]) ->
     // This unwrap is safe because the output length is a known constant with these inputs
 
 
-    session.s_pub_i = PublicKey::from(<Vec<u8> as TryInto<[u8; 32]>>::try_into(match qcrypto_aead_decrypt(&k, 0, &msg.static_pub, &h) {
+    let s_pub_i = PublicKey::from(<Vec<u8> as TryInto<[u8; 32]>>::try_into(match qcrypto_aead_decrypt(&k, 0, &msg.static_pub, &h) {
         Ok(s) => s,
         Err(e) => return Err(NoiseError::ChaCha20Error(e))
     }).unwrap());
 
     let h = qcrypto_hash_twice(&h, &msg.static_pub);
 
-    let ci_k_pair = qcrypto_hkdf::<2>(&ck, qcrypto_dh_longterm(session.s_priv_me, &session.s_pub_i).as_bytes());
+    let ci_k_pair = qcrypto_hkdf::<2>(&ck, qcrypto_dh_longterm(session.s_priv_me, &s_pub_i).as_bytes());
     let ck = ci_k_pair[0];
     let k = ci_k_pair[1];
 
@@ -172,7 +171,7 @@ pub fn parse_handshake_init(session: &mut HandshakeState, packet: [u8; 148]) ->
 
     // we need to check mac1 and mac2
 
-    let mac1: [u8; 16] = qcrypto_mac(&qcrypto_hash_twice(LABEL_MAC1.as_bytes(), session.s_pub_i.as_bytes()), &packet[..116]);
+    let mac1: [u8; 16] = qcrypto_mac(&qcrypto_hash_twice(LABEL_MAC1.as_bytes(), s_pub_i.as_bytes()), &packet[..116]);
     let mac2 = if needs_cookie(session) { qcrypto_mac(&session.cookies[session.cookies.len() - 1].cookie, &packet[..132]) } else { [0u8; 16] };
 
     if mac1 != msg.mac1 || mac2 != msg.mac2 {

quicktap/src/stack/entry.rs

@@ -1,14 +0,0 @@
-//! The ENTRY stage of the packet processing stack. Provides a `PacketEntryStage` which implements `PacketProcessingStage`.
-
-use std::error::Error;
-use std::net::SocketAddr;
-use crate::stack::{PacketProcessingStage};
-
-/// The ENTRY stage of the packet processing stack
-pub struct PacketEntryStage {}
-
-impl PacketProcessingStage for PacketEntryStage {
-    fn process_packet(pkt: Vec<u8>, from: &SocketAddr) -> Result<(), Box<dyn Error>> {
-        Ok(())
-    }
-}

quicktap/src/stack/entry_udp.rs

@@ -0,0 +1,15 @@
+//! The ENTRY stage of the packet processing stack. Provides a `PacketEntryStage` which implements `PacketProcessingStage`.
+
+use std::error::Error;
+use std::net::SocketAddr;
+use crate::device::QTInterface;
+use crate::stack::{PacketProcessingStage};
+
+/// The ENTRY stage of the packet processing stack for UDP packets
+pub struct UDPPacketEntryStage {}
+
+impl PacketProcessingStage for UDPPacketEntryStage {
+    fn process_packet(pkt: Vec<u8>, from: &SocketAddr, interface: &QTInterface) -> Result<(), Box<dyn Error>> {
+        unimplemented!();
+    }
+}

quicktap/src/stack/mod.rs

@@ -26,8 +26,9 @@
 
 use std::error::Error;
 use std::net::SocketAddr;
+use crate::device::QTInterface;
 
-pub mod entry;
+pub mod entry_udp;
 
 /// The methods and functions that need to be implemented by a stage in the packet processor
 pub trait PacketProcessingStage {
@@ -35,5 +36,5 @@ pub trait PacketProcessingStage {
     /// For example, if you are the CRYPT layer, and are processing a tun packet, assume that the ENTRY and ROUTING stack stages have already been completed and you are being given the result of that processing.
     /// # Errors
     /// This function will error if an error occurs
-    fn process_packet(pkt: Vec<u8>, from: &SocketAddr) -> Result<(), Box<dyn Error>> where Self: Sized;
+    fn process_packet(pkt: Vec<u8>, from: &SocketAddr, interface: &QTInterface) -> Result<(), Box<dyn Error>> where Self: Sized;
 }