Rust wrapper: add password-hash, kem, mac traits; fix a few Fenrir findings by holtrop-wolfssl · Pull Request #10305 · wolfSSL/wolfssl

holtrop-wolfssl · 2026-04-24T17:59:21Z

Description

Rust wrapper: add password-hash, kem, mac traits; fix a few Fenrir findings

Testing

Unit/CI tests

Checklist

added tests
updated/added doxygen
updated appropriate READMEs
Updated manual and documentation

Fixes F-3092

…_key() Fixes F-3093

Fixes F-1989

Fixes F-3094

Fixes F-2676

Copilot

Pull request overview

Note

Copilot was unable to run its full agentic suite in this review.

Adds RustCrypto trait support (password-hash, KEM, MAC) to the wolfCrypt Rust wrapper while addressing several static-analysis (Fenrir) findings and aligning tests/docs with API changes.

Changes:

Add PBKDF2 password-hash (PHC) hasher/verifier support and corresponding tests.
Add ML-KEM RustCrypto kem trait wrappers and tests.
Add HMAC/CMAC RustCrypto digest::Mac wrappers and tests; include ECC/LMS/ML-KEM fixes and doc/test updates.

Reviewed changes

Copilot reviewed 17 out of 18 changed files in this pull request and generated 8 comments.

Show a summary per file

File	Description
wrapper/rust/wolfssl-wolfcrypt/src/pbkdf2_password_hash.rs	Implements `password-hash` traits for PBKDF2 and PHC formatting/parsing.
wrapper/rust/wolfssl-wolfcrypt/tests/test_pbkdf2_password_hash.rs	Adds PBKDF2 password-hash tests (roundtrip, params, algorithm variants).
wrapper/rust/wolfssl-wolfcrypt/src/mlkem_kem.rs	Adds RustCrypto `kem` trait wrappers for ML-KEM.
wrapper/rust/wolfssl-wolfcrypt/tests/test_mlkem_kem.rs	Adds ML-KEM KEM trait tests (roundtrip, export/import, rejection).
wrapper/rust/wolfssl-wolfcrypt/src/hmac_mac.rs	Adds RustCrypto `digest::Mac` trait wrappers for HMAC variants.
wrapper/rust/wolfssl-wolfcrypt/tests/test_hmac_mac.rs	Adds HMAC MAC-trait vector and behavior tests.
wrapper/rust/wolfssl-wolfcrypt/src/cmac_mac.rs	Adds RustCrypto `digest::Mac` trait wrappers for AES-CMAC.
wrapper/rust/wolfssl-wolfcrypt/tests/test_cmac_mac.rs	Adds CMAC MAC-trait tests including wrong key size.
wrapper/rust/wolfssl-wolfcrypt/src/mlkem.rs	Changes ML-KEM encode APIs to return `Result<(), i32>` and updates docs.
wrapper/rust/wolfssl-wolfcrypt/tests/test_mlkem.rs	Updates ML-KEM tests for new encode API return type.
wrapper/rust/wolfssl-wolfcrypt/src/lms.rs	Renames signature-availability API to `has_sigs_left` and updates docs.
wrapper/rust/wolfssl-wolfcrypt/tests/test_lms.rs	Updates tests for `has_sigs_left` rename.
wrapper/rust/wolfssl-wolfcrypt/src/ecc.rs	Adds NUL-termination validation and adjusts return-value handling.
wrapper/rust/wolfssl-wolfcrypt/tests/test_ecc.rs	Adds test coverage for rs_hex_to_sig NUL-termination behavior.
wrapper/rust/wolfssl-wolfcrypt/src/lib.rs	Exposes new modules behind feature/cfg gates.
wrapper/rust/wolfssl-wolfcrypt/Cargo.toml	Adds new features/deps for `mac`, `password-hash`, `kem`, `hybrid-array`.
wrapper/rust/wolfssl-wolfcrypt/Makefile	Enables new features in the default feature list.

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Copilot · 2026-04-24T18:08:09Z

+        let mut out_buf = [0u8; Output::MAX_LENGTH];
+        let out_slice = &mut out_buf[..params.output_len];
+        kdf::pbkdf2(password, salt.as_ref(), iterations, algorithm.hmac_type(), out_slice)
+            .map_err(|_| Error::Crypto)?;
+        let output = Output::new(out_slice)?;


params.output_len is used to slice out_buf without validating it is within 1..=Output::MAX_LENGTH. If a caller supplies output_len > Output::MAX_LENGTH, this will panic (DoS). Add explicit bounds validation for params.output_len and return Error::ParamInvalid { name: "l" } (or similar) instead of panicking.

Copilot · 2026-04-24T18:08:10Z

+        let output_len = if let Some(ref h) = hash.hash {
+            h.len()
+        } else if let Some(l) = hash.params.get_decimal("l") {
+            l as usize


l as usize is accepted without validating the size is sane (e.g., non-zero and <= Output::MAX_LENGTH). This can later lead to panics when allocating/slicing output buffers based on parsed PHC parameters. Validate l (range + overflow-safe conversion) and reject invalid values with Error::ParamInvalid { name: "l" }.

Suggested change

l as usize

let output_len =

usize::try_from(l).map_err(|_| Error::ParamInvalid { name: "l" })?;

if output_len == 0 || output_len > Output::MAX_LENGTH {

return Err(Error::ParamInvalid { name: "l" });

}

output_len

Copilot · 2026-04-24T18:08:10Z

    /// }
    /// ```
    pub fn rs_hex_to_sig(r: &[u8], s: &[u8], dout: &mut [u8]) -> Result<usize, i32> {
+        if r[r.len() - 1] != 0 || s[s.len() - 1] != 0 {


This will panic if r or s is empty due to r[r.len() - 1]. Add an explicit empty-slice guard (treat empty as BAD_FUNC_ARG) before checking the trailing NUL byte.

Suggested change

if r[r.len() - 1] != 0 || s[s.len() - 1] != 0 {

if r.is_empty() || s.is_empty() || r[r.len() - 1] != 0 || s[s.len() - 1] != 0 {

Copilot · 2026-04-24T18:08:11Z

+#[test]
+fn test_ecc_rs_hex_to_sig_not_null_terminated() {
+    let r_hex = b"AABB\0";
+    let s_hex = b"CCDD\0";
+    let r_hex_no_nul = b"AABB";
+    let s_hex_no_nul = b"CCDD";
+    let mut sig_out = [0u8; 128];
+
+    // Both null-terminated should succeed
+    assert!(ECC::rs_hex_to_sig(r_hex, s_hex, &mut sig_out).is_ok());


Most tests in this crate call common::setup() to ensure wolfCrypt is initialized. This new test does not, which can make it order-dependent if initialization is required. Add common::setup(); at the start of this test for consistency and to avoid potential flakes.

Copilot · 2026-04-24T18:08:11Z

+#[cfg(feature = "kem")]
+pub mod mlkem_kem;


The module declarations are gated only on the Cargo features, but the module files themselves have stricter cfgs (mlkem_kem requires mlkem, pbkdf2_password_hash requires hmac + kdf_pbkdf2). This can expose “present but empty” modules (or missing items) when the feature is enabled without the underlying algorithm cfgs. Align the lib.rs #[cfg(...)] conditions with the module-level cfg requirements to make the public API predictable.

Copilot · 2026-04-24T18:08:11Z

+#[cfg(feature = "password-hash")]
+pub mod pbkdf2_password_hash;


The module declarations are gated only on the Cargo features, but the module files themselves have stricter cfgs (mlkem_kem requires mlkem, pbkdf2_password_hash requires hmac + kdf_pbkdf2). This can expose “present but empty” modules (or missing items) when the feature is enabled without the underlying algorithm cfgs. Align the lib.rs #[cfg(...)] conditions with the module-level cfg requirements to make the public API predictable.

Copilot · 2026-04-24T18:08:11Z

    }

-    /// Return the number of signatures remaining for this key.
+    /// Return whether there are more signatures remaining for this key.


Renaming sigs_left to has_sigs_left is a breaking change for any downstream users. Consider keeping sigs_left as a deprecated wrapper around has_sigs_left (at least for one release), so consumers get a graceful transition path.

Copilot · 2026-04-24T18:08:12Z

+    pub fn has_sigs_left(&mut self) -> Result<bool, i32> {
        let rc = unsafe { sys::wc_LmsKey_SigsLeft(&mut self.ws_key) };


Renaming sigs_left to has_sigs_left is a breaking change for any downstream users. Consider keeping sigs_left as a deprecated wrapper around has_sigs_left (at least for one release), so consumers get a graceful transition path.

github-actions · 2026-04-24T18:44:07Z

MemBrowse Memory Report

No memory changes detected for:

holtrop-wolfssl added 8 commits April 24, 2026 13:58

Rust wrapper: implement password-hash traits

bb7196e

Rust wrapper: implement kem traits

168b587

Rust wrapper: add mac feature and implement digest/mac traits

52c867e

Rust wrapper: check for NUL-terminated slice in ECC::rs_hex_to_sig

69d3bc3

Fixes F-3092

Rust wrapper: remove return value from MlKem::encode_{public,private}…

39facd1

…_key() Fixes F-3093

Rust wrapper: make ECC::verify_hash C result check more strict

6b2b263

Fixes F-1989

Rust wrapper: replace Lms::sigs_left() with Lms::has_sigs_left()

8fa8a67

Fixes F-3094

Rust wrapper: use consistent rc check in ECC::shared_secret

d2632b3

Fixes F-2676

holtrop-wolfssl self-assigned this Apr 24, 2026

Copilot AI review requested due to automatic review settings April 24, 2026 17:59

Copilot AI reviewed Apr 24, 2026

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Copilot started reviewing on behalf of holtrop-wolfssl April 24, 2026 18:10 View session

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Rust wrapper: add password-hash, kem, mac traits; fix a few Fenrir findings#10305

Rust wrapper: add password-hash, kem, mac traits; fix a few Fenrir findings#10305
holtrop-wolfssl wants to merge 8 commits intowolfSSL:masterfrom
holtrop-wolfssl:rust-crate-updates

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	if r[r.len() - 1] != 0 \|\| s[s.len() - 1] != 0 {
	if r.is_empty() \|\| s.is_empty() \|\| r[r.len() - 1] != 0 \|\| s[s.len() - 1] != 0 {

		#[cfg(feature = "password-hash")]
		pub mod pbkdf2_password_hash;

		pub fn has_sigs_left(&mut self) -> Result<bool, i32> {
		let rc = unsafe { sys::wc_LmsKey_SigsLeft(&mut self.ws_key) };

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holtrop-wolfssl commented Apr 24, 2026

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