From 623ea191c11dbfb34887635a03c3dc5ff08ef9f1 Mon Sep 17 00:00:00 2001
From: Thomas Eizinger <thomas@eizinger.io>
Date: Mon, 16 Oct 2023 11:48:43 +1100
Subject: [PATCH] Make `Tunn::new` infallible

---
 boringtun/src/device/mod.rs      |  3 +--
 boringtun/src/ffi/mod.rs         |  7 ++-----
 boringtun/src/noise/handshake.rs | 14 +++++++-------
 boringtun/src/noise/mod.rs       | 15 ++++++---------
 4 files changed, 16 insertions(+), 23 deletions(-)

diff --git a/boringtun/src/device/mod.rs b/boringtun/src/device/mod.rs
index bc14c896..8cd1c7c8 100644
--- a/boringtun/src/device/mod.rs
+++ b/boringtun/src/device/mod.rs
@@ -334,8 +334,7 @@ impl Device {
             keepalive,
             next_index,
             None,
-        )
-        .unwrap();
+        );
 
         let peer = Peer::new(tunn, next_index, endpoint, allowed_ips, preshared_key);
 
diff --git a/boringtun/src/ffi/mod.rs b/boringtun/src/ffi/mod.rs
index 3b4e3bb3..1e5a2a9f 100644
--- a/boringtun/src/ffi/mod.rs
+++ b/boringtun/src/ffi/mod.rs
@@ -292,17 +292,14 @@ pub unsafe extern "C" fn new_tunnel(
         Some(keep_alive)
     };
 
-    let tunnel = match Tunn::new(
+    let tunnel = Box::new(Mutex::new(Tunn::new(
         private_key,
         public_key,
         preshared_key,
         keep_alive,
         index,
         None,
-    ) {
-        Ok(t) => Box::new(Mutex::new(t)),
-        Err(_) => return ptr::null_mut(),
-    };
+    )));
 
     PANIC_HOOK.call_once(|| {
         // FFI won't properly unwind on panic, but it will if we cause a segmentation fault
diff --git a/boringtun/src/noise/handshake.rs b/boringtun/src/noise/handshake.rs
index b7c93731..2ee6711f 100644
--- a/boringtun/src/noise/handshake.rs
+++ b/boringtun/src/noise/handshake.rs
@@ -375,19 +375,19 @@ impl NoiseParams {
         static_public: x25519::PublicKey,
         peer_static_public: x25519::PublicKey,
         preshared_key: Option<[u8; 32]>,
-    ) -> Result<NoiseParams, WireGuardError> {
+    ) -> NoiseParams {
         let static_shared = static_private.diffie_hellman(&peer_static_public);
 
         let initial_sending_mac_key = b2s_hash(LABEL_MAC1, peer_static_public.as_bytes());
 
-        Ok(NoiseParams {
+        NoiseParams {
             static_public,
             static_private,
             peer_static_public,
             static_shared,
             sending_mac1_key: initial_sending_mac_key,
             preshared_key,
-        })
+        }
     }
 
     /// Set a new private key
@@ -415,15 +415,15 @@ impl Handshake {
         peer_static_public: x25519::PublicKey,
         global_idx: u32,
         preshared_key: Option<[u8; 32]>,
-    ) -> Result<Handshake, WireGuardError> {
+    ) -> Handshake {
         let params = NoiseParams::new(
             static_private,
             static_public,
             peer_static_public,
             preshared_key,
-        )?;
+        );
 
-        Ok(Handshake {
+        Handshake {
             params,
             next_index: global_idx,
             previous: HandshakeState::None,
@@ -432,7 +432,7 @@ impl Handshake {
             stamper: TimeStamper::new(),
             cookies: Default::default(),
             last_rtt: None,
-        })
+        }
     }
 
     pub(crate) fn is_in_progress(&self) -> bool {
diff --git a/boringtun/src/noise/mod.rs b/boringtun/src/noise/mod.rs
index 79a6b923..62cec983 100644
--- a/boringtun/src/noise/mod.rs
+++ b/boringtun/src/noise/mod.rs
@@ -198,18 +198,17 @@ impl Tunn {
         persistent_keepalive: Option<u16>,
         index: u32,
         rate_limiter: Option<Arc<RateLimiter>>,
-    ) -> Result<Self, &'static str> {
+    ) -> Self {
         let static_public = x25519::PublicKey::from(&static_private);
 
-        let tunn = Tunn {
+        Tunn {
             handshake: Handshake::new(
                 static_private,
                 static_public,
                 peer_static_public,
                 index << 8,
                 preshared_key,
-            )
-            .map_err(|_| "Invalid parameters")?,
+            ),
             sessions: Default::default(),
             current: Default::default(),
             tx_bytes: Default::default(),
@@ -221,9 +220,7 @@ impl Tunn {
             rate_limiter: rate_limiter.unwrap_or_else(|| {
                 Arc::new(RateLimiter::new(&static_public, PEER_HANDSHAKE_RATE_LIMIT))
             }),
-        };
-
-        Ok(tunn)
+        }
     }
 
     /// Update the private key and clear existing sessions
@@ -606,10 +603,10 @@ mod tests {
         let their_public_key = x25519_dalek::PublicKey::from(&their_secret_key);
         let their_idx = OsRng.next_u32();
 
-        let my_tun = Tunn::new(my_secret_key, their_public_key, None, None, my_idx, None).unwrap();
+        let my_tun = Tunn::new(my_secret_key, their_public_key, None, None, my_idx, None);
 
         let their_tun =
-            Tunn::new(their_secret_key, my_public_key, None, None, their_idx, None).unwrap();
+            Tunn::new(their_secret_key, my_public_key, None, None, their_idx, None);
 
         (my_tun, their_tun)
     }