wgctrl-rs(userspace): remove subtle as dependency

Cargo.lock

@@ -1367,7 +1367,6 @@ dependencies = [
  "hex",
  "libc",
  "rand_core",
- "subtle",
  "wgctrl-sys",
 ]
 

server/src/main.rs

@@ -615,7 +615,7 @@ fn get_session(
         .ok_or(ServerError::Unauthorized)?;
     let pubkey = pubkey.to_str().map_err(|_| ServerError::Unauthorized)?;
     let pubkey = Key::from_base64(pubkey).map_err(|_| ServerError::Unauthorized)?;
-    if pubkey.ct_eq(&context.public_key).into() {
+    if pubkey.as_bytes().ct_eq(&context.public_key.as_bytes()).into() {
         let peer = DatabasePeer::get_from_ip(&context.db.lock(), addr).map_err(|e| match e {
             rusqlite::Error::QueryReturnedNoRows => ServerError::Unauthorized,
             e => ServerError::Database(e),

wgctrl-rs/Cargo.toml

@@ -19,5 +19,4 @@ wgctrl-sys = { path = "../wgctrl-sys" }
 
 [target.'cfg(not(target_os = "linux"))'.dependencies]
 rand_core = "0.6"
-subtle = "2"
 curve25519-dalek = "4.0.0-pre.1"

wgctrl-rs/src/backends/kernel.rs

@@ -468,9 +468,8 @@ impl Key {
         Self(wgctrl_sys::wg_key::default())
     }
 
-    /// Checks if this key is all-zero.
-    pub fn is_zero(&self) -> bool {
-        unsafe { wgctrl_sys::wg_key_is_zero(&self.0 as *const u8 as *mut u8) }
+    pub fn as_bytes(&self) -> &[u8] {
+        &self.0
     }
 
     /// Converts the key to a standardized base64 representation, as used by the `wg` utility and `wg-quick`.

wgctrl-rs/src/backends/userspace.rs

@@ -1,6 +1,3 @@
-use curve25519_dalek::scalar::Scalar;
-use subtle::ConstantTimeEq;
-
 use crate::{Backend, Device, DeviceUpdate, InterfaceName, PeerConfig, PeerInfo, PeerStats};
 
 #[cfg(target_os = "linux")]
@@ -395,12 +392,6 @@ pub fn apply(builder: &DeviceUpdate, iface: &InterfaceName) -> io::Result<()> {
 #[derive(PartialEq, Eq, Clone)]
 pub struct Key([u8; 32]);
 
-impl ConstantTimeEq for Key {
-    fn ct_eq(&self, other: &Self) -> subtle::Choice {
-        self.0.ct_eq(&other.0).into()
-    }
-}
-
 #[cfg(not(target_os = "linux"))]
 impl Key {
     /// Generates and returns a new private key.
@@ -428,6 +419,8 @@ impl Key {
 
     /// Generates a public key for this private key.
     pub fn generate_public(&self) -> Self {
+        use curve25519_dalek::scalar::Scalar;
+
         use curve25519_dalek::constants::ED25519_BASEPOINT_TABLE;
 
         // https://github.com/dalek-cryptography/x25519-dalek/blob/1c39ff92e0dfc0b24aa02d694f26f3b9539322a5/src/x25519.rs#L150
@@ -441,9 +434,8 @@ impl Key {
         Self([0u8; 32])
     }
 
-    /// Checks if this key is all-zero.
-    pub fn is_zero(&self) -> bool {
-        self.ct_eq(&Self::zero()).into()
+    pub fn as_bytes(&self) -> &[u8] {
+        &self.0
     }
 
     /// Converts the key to a standardized base64 representation, as used by the `wg` utility and `wg-quick`.
@@ -496,22 +488,22 @@ mod test {
     #[test]
     fn test_rng_sanity_private() {
         let first = Key::generate_private();
-        assert!(!first.is_zero());
+        assert!(first.as_bytes() != &[0u8; 32]);
         for _ in 0..100_000 {
             let key = Key::generate_private();
             assert!(first != key);
-            assert!(!key.is_zero());
+            assert!(key.as_bytes() != &[0u8; 32]);
         }
     }
 
     #[test]
     fn test_rng_sanity_preshared() {
         let first = Key::generate_preshared();
-        assert!(!first.is_zero());
+        assert!(first.as_bytes() != &[0u8; 32]);
         for _ in 0..100_000 {
             let key = Key::generate_preshared();
             assert!(first != key);
-            assert!(!key.is_zero());
+            assert!(key.as_bytes() != &[0u8; 32]);
         }
     }
 }

wgctrl-rs/src/key.rs

@@ -73,11 +73,8 @@ mod tests {
     fn test_key_zero() {
         use crate::key::Key;
 
-        let key = Key::zero();
-        assert!(key.is_zero());
-
         let key = Key::generate_preshared();
-        assert!(!key.is_zero());
+        assert_ne!(key.as_bytes(), &[0u8; 32]);
     }
 
     #[test]