keyforkd: require hardened derivation on two highest indexes

Cargo.lock

@@ -1879,7 +1879,7 @@ dependencies = [
 
 [[package]]
 name = "keyforkd"
-version = "0.1.0"
+version = "0.1.1"
 dependencies = [
  "bincode",
  "hex-literal",

crates/daemon/keyforkd-client/src/tests.rs

@@ -25,6 +25,9 @@ fn secp256k1_test_suite() {
                 if chain_len < 2 {
                     continue;
                 }
+                if chain.iter().take(2).any(|index| !index.is_hardened()) {
+                    continue;
+                }
                 // Consistency check: ensure the server and the client can each derive the same
                 // key using an XPrv, for all but the last XPrv, which is verified after this
                 for i in 2..chain_len {

crates/daemon/keyforkd-models/src/lib.rs

@@ -43,6 +43,10 @@ pub enum DerivationError {
     #[error("Invalid derivation length: Expected at least 2, actual: {0}")]
     InvalidDerivationLength(usize),
 
+    /// The derivation request did not use hardened derivation on the 2 highest indexes.
+    #[error("Invalid derivation paths: expected index #{0} (1) to be hardened")]
+    InvalidDerivationPath(usize, u32),
+
     /// An error occurred while deriving data.
     #[error("Derivation error: {0}")]
     Derivation(String),

crates/daemon/keyforkd/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "keyforkd"
-version = "0.1.0"
+version = "0.1.1"
 edition = "2021"
 license = "AGPL-3.0-only"
 

crates/daemon/keyforkd/src/service.rs

@@ -69,6 +69,18 @@ impl Service<Request> for Keyforkd {
                     return Err(DerivationError::InvalidDerivationLength(len).into());
                 }
 
+                if let Some((i, unhardened_index)) = req
+                    .path()
+                    .iter()
+                    .take(2)
+                    .enumerate()
+                    .find(|(_, index)| {
+                        !index.is_hardened()
+                    })
+                {
+                    return Err(DerivationError::InvalidDerivationPath(i, unhardened_index.inner()).into())
+                }
+
                 #[cfg(feature = "tracing")]
                 if let Some(target) = guess_target(req.path()) {
                     info!("Deriving path: {target}");
@@ -110,6 +122,9 @@ mod tests {
                 if chain.len() < 2 {
                     continue;
                 }
+                if chain.iter().take(2).any(|index| !index.is_hardened()) {
+                    continue;
+                }
                 let req = DerivationRequest::new(DerivationAlgorithm::Secp256k1, &chain);
                 let response: DerivationResponse = keyforkd
                     .ready()

crates/daemon/keyforkd/src/test_util.rs

@@ -61,7 +61,7 @@ where
         ));
     let socket_dir = tempfile::tempdir().expect(bug!("can't create tempdir"));
     let socket_path = socket_dir.path().join("keyforkd.sock");
-    rt.block_on(async move {
+    let result = rt.block_on(async move {
         let (tx, mut rx) = tokio::sync::mpsc::channel(1);
         let server_handle = tokio::spawn({
             let socket_path = socket_path.clone();
@@ -87,8 +87,13 @@ where
         let result = test_handle.await;
         server_handle.abort();
         result
-    })
-    .expect(bug!("runtime could not join all threads"))
+    });
+    if let Err(e) = result {
+        if e.is_panic() {
+            std::panic::resume_unwind(e.into_panic());
+        }
+    }
+    Ok(())
 }
 
 #[cfg(test)]