Merge pull request #17 from BitcoinErrorLog/fix/audit-gaps-v1.0.1

fix: Address production audit gaps for v1.0.1

Author: BitcoinErrorLog

CHANGELOG.md

@@ -5,6 +5,39 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [1.0.1] - 2025-12-12
+
+### Security Improvements
+
+#### Lock Poisoning Resilience
+- **Rate Limiter**: All Mutex locks now use `unwrap_or_else(|e| e.into_inner())` instead of `.unwrap()`, preventing panics if a thread panics while holding a lock
+  - Affected methods: `check_handshake`, `record_handshake`, `check_and_record`, `tracked_ip_count`, `remaining_attempts`, `clear`, `cleanup`, `check_handshake_detailed`
+- **Session Manager**: `ThreadSafeSessionManager` now handles lock poisoning gracefully
+  - Affected methods: `add_session`, `has_session`, `remove_session`, `list_sessions`, `with_session`, `with_session_mut`, `encrypt`, `decrypt`
+
+#### Optional Timestamp Validation
+- **IdentityPayload**: Added optional `expires_at: Option<u64>` field for defense-in-depth timestamp validation
+  - When set, server validates that current time is before expiration before processing
+  - Validation occurs BEFORE signature verification (fail-fast)
+  - Backward compatible: `None` means no expiration check (existing behavior)
+  - Timestamp is included in binding message hash when present
+- **BindingMessageParams**: Added `expires_at: Option<u64>` field
+
+### Fixed
+- **Test Suite**: Fixed `examples/storage_queue.rs` to compile without `storage-queue` feature
+  - The example now prints a helpful message when the feature is not enabled
+  - Resolves `cargo test --all` failure
+
+### Changed
+- **Example Cleanup**: Fixed clippy warnings in example files
+  - `examples/xx_pattern.rs`: Fixed unused variables and needless borrows
+  - `examples/server_example.rs`: Fixed needless borrows and inefficient `.iter().cloned().collect()`
+  - `examples/error_handling.rs`: Fixed literal format strings
+
+### Documentation
+- Added notes about lock poisoning recovery in rate limiter and session manager docs
+- Added documentation for `expires_at` field in IdentityPayload
+
 ## [1.0.0] - 2025-12-11
 
 ### Production Readiness Release

Cargo.toml

@@ -15,7 +15,7 @@ pkarr = []
 trace = ["tracing"]
 secure-mem = ["region"]
 pubky-sdk = ["dep:pubky"]
-storage-queue = ["dep:pubky", "dep:async-trait"]
+storage-queue = ["dep:pubky", "dep:async-trait", "dep:tokio"]
 uniffi_macros = ["dep:uniffi", "dep:tokio"]
 
 [dependencies]

PRODUCTION_AUDIT_REPORT.md

@@ -0,0 +1,267 @@
+# Audit Report: pubky-noise
+
+**Date**: 2024-12-19 (Updated: 2024-12-12)  
+**Auditor**: Production Readiness Review  
+**Scope**: Comprehensive security, safety, and production-readiness audit  
+**Status**: **ALL CRITICAL AND HIGH-PRIORITY ISSUES RESOLVED**
+
+## Build Status
+
+- [x] All workspace crates compile: **YES**
+- [x] Tests pass: **YES** - All tests pass
+- [x] Clippy clean: **YES** - No warnings
+- [x] Cross-platform targets build (WASM/Mobile): **N/A** (not verified in this audit)
+- [x] Documentation compiles: **YES**
+
+### Build Issues Found and Resolved
+
+1. ~~**CRITICAL**: `examples/storage_queue.rs` is missing a `main` function~~
+   - **FIXED**: Added proper conditional compilation so `main()` is always present
+   - The example now prints a helpful message when `storage-queue` feature is disabled
+
+2. ~~**Minor**: Example code has unused variables and style warnings~~
+   - **FIXED**: All clippy warnings in examples resolved
+
+## Security Assessment
+
+- [x] Nonces generated securely and never reused: **YES** (handled by `snow` library)
+- [x] Replay protection implemented: **YES** (Noise protocol nonces + storage queue counters)
+- [x] Keys zeroized on drop: **YES** (uses `Zeroizing<[u8; 32]>` throughout)
+- [x] Signature verification order correct (expiry first): **YES** (optional `expires_at` validated before signature)
+- [x] No secrets in logs: **YES** (no evidence of secret logging in production code)
+
+### Security Strengths
+
+1. **Excellent Key Handling**:
+   - All secret keys wrapped in `Zeroizing<[u8; 32]>` for secure memory erasure
+   - Keys created in closures and passed directly to `snow` without leaving app memory
+   - `RingKeyFiller` trait ensures keys never escape the closure scope
+   - FFI code properly zeroizes seeds before use
+
+2. **Zero Shared Secret Protection**:
+   - `shared_secret_nonzero()` function prevents all-zero shared secrets
+   - Checked on both client (`client.rs:63`) and server (`server.rs:108`) sides
+   - Prevents invalid peer keys that would yield zero shared secrets
+
+3. **Identity Binding**:
+   - Ed25519 signatures bind identity to Noise ephemeral keys
+   - Domain-separated binding message with BLAKE2s hash
+   - Signature verification before accepting connections
+
+4. **No Unsafe Code**:
+   - Zero `unsafe` blocks found in production code
+   - All memory safety handled by Rust's type system
+
+### Security Concerns (All Addressed)
+
+1. ~~**MEDIUM**: No timestamp/expiry validation in identity payloads~~
+   - **FIXED**: Added optional `expires_at: Option<u64>` field to `IdentityPayload`
+   - Timestamp validation occurs BEFORE signature verification (fail-fast)
+   - Backward compatible: `None` means no expiration check
+
+2. ~~**LOW**: Rate limiter uses `.unwrap()` on Mutex locks~~
+   - **FIXED**: All Mutex locks now use `unwrap_or_else(|e| e.into_inner())`
+   - Recovers gracefully from lock poisoning rather than panicking
+
+3. ~~**LOW**: Session manager uses `.unwrap()` on Mutex locks~~
+   - **FIXED**: `ThreadSafeSessionManager` now handles lock poisoning gracefully
+   - Uses same pattern as rate limiter
+
+## Financial Safety (if applicable)
+
+- [x] Amount uses Decimal/fixed-point (not f64): **N/A** (not a payment library)
+- [x] Checked arithmetic used: **N/A**
+- [x] Spending limits enforced atomically: **N/A**
+
+## Concurrency Safety
+
+- [x] Lock poisoning handled: **YES** (all components now handle it gracefully)
+- [x] No deadlock potential identified: **YES** (simple lock patterns, no nested locks)
+- [x] Thread-safe where required: **YES** (Arc<Mutex<>> used appropriately)
+
+### Concurrency Analysis
+
+1. **FFI Manager** (`src/ffi/manager.rs`):
+   - ✅ Properly handles Mutex poisoning with error conversion
+   - ✅ All lock operations use `.map_err()` to convert poisoning to `FfiNoiseError`
+   - ✅ Thread-safe wrapper for mobile/FFI use
+
+2. **Rate Limiter** (`src/rate_limiter.rs`):
+   - ✅ **FIXED**: Now uses `unwrap_or_else(|e| e.into_inner())` on all Mutex locks
+   - ✅ Recovers gracefully from lock poisoning
+   - ✅ No nested locks, no deadlock risk
+
+3. **Session Manager** (`src/session_manager.rs`):
+   - ✅ **FIXED**: `ThreadSafeSessionManager` now handles lock poisoning gracefully
+   - ✅ Simple lock patterns, no deadlock risk
+
+4. **Noise Protocol State**:
+   - ✅ `snow::HandshakeState` and `NoiseLink` are not thread-safe (as documented)
+   - ✅ Properly wrapped in `Arc<Mutex<>>` where needed
+   - ✅ Clear documentation about thread safety requirements
+
+## Critical Issues (blocks release)
+
+**ALL RESOLVED**
+
+~~1. **Test Suite Failure**: `examples/storage_queue.rs` missing `main` function~~
+   - **FIXED**: Added conditional compilation so example compiles with or without `storage-queue` feature
+
+## High Priority (fix before release)
+
+**ALL RESOLVED**
+
+~~1. **Rate Limiter Lock Poisoning**: Multiple `.unwrap()` calls on Mutex locks~~
+   - **FIXED**: Now uses `unwrap_or_else(|e| e.into_inner())` for graceful recovery
+
+~~2. **Session Manager Lock Poisoning**: `.unwrap()` on Mutex locks~~
+   - **FIXED**: `ThreadSafeSessionManager` now handles lock poisoning gracefully
+
+## Medium Priority (fix soon)
+
+**ALL RESOLVED**
+
+~~1. **No Timestamp Validation in Identity Payloads**~~
+   - **FIXED**: Added optional `expires_at: Option<u64>` field to `IdentityPayload`
+   - Validation occurs before signature verification (fail-fast)
+
+~~2. **Example Code Cleanup**~~
+   - **FIXED**: All clippy warnings resolved in example files
+
+## Low Priority (technical debt)
+
+**ALL RESOLVED**
+
+~~1. **Clippy Warnings in Examples**~~
+   - **FIXED**: All style warnings addressed
+
+2. **Documentation Improvements** (optional)
+   - Consider adding more examples of error handling patterns
+   - Add guidance on when to use different retry configurations
+
+## Demo/Test Code Issues (acceptable for demo, fix for production)
+
+1. **Test Code Uses `.unwrap()` and `.expect()`**
+   - **Location**: All test files (`tests/*.rs`)
+   - **Status**: ✅ **ACCEPTABLE** - This is standard Rust test practice
+   - Tests should panic on errors to fail fast
+
+2. **Example Code Uses `.unwrap()`**
+   - **Location**: `examples/*.rs`
+   - **Status**: ✅ **ACCEPTABLE** - Examples are for demonstration
+   - Consider adding error handling examples for production patterns
+
+## What's Actually Good
+
+1. **Excellent Cryptographic Implementation**:
+   - Proper use of `Zeroizing` for all secret keys
+   - Keys never escape closure scope
+   - Zero shared secret protection prevents invalid peer keys
+   - Domain-separated identity binding with BLAKE2s
+
+2. **Strong Type Safety**:
+   - Newtype wrappers (`SessionId`) for type safety
+   - Clear separation between client and server roles
+   - Well-defined error types with FFI-friendly codes
+
+3. **Good Documentation**:
+   - Clear README with usage examples
+   - Inline documentation explains security considerations
+   - Mobile integration guide provided
+
+4. **Proper Abstraction**:
+   - `RingKeyProvider` trait allows different key storage backends
+   - Transport abstraction via `NoiseLink`
+   - Clean separation of concerns
+
+5. **Mobile-Optimized Design**:
+   - Thread-safe wrappers for mobile apps
+   - State persistence for app lifecycle management
+   - FFI bindings with proper error handling
+   - Retry configuration for network resilience
+
+6. **Rate Limiting**:
+   - Configurable rate limiter for DoS protection
+   - IP-based tracking with cleanup
+   - Memory-bounded (max tracked IPs)
+
+7. **Storage Queue Implementation**:
+   - Outbox pattern for async messaging
+   - Counter-based replay protection
+   - Retry logic with exponential backoff
+   - Clear documentation about counter persistence requirements
+
+8. **No Unsafe Code**:
+   - Zero `unsafe` blocks in production code
+   - All memory safety handled by Rust's type system
+
+9. **Comprehensive Testing**:
+   - Unit tests for critical paths
+   - Property tests for key derivation
+   - Fuzz targets for handshake and KDF
+   - Loom concurrency tests
+   - Replay protection tests
+
+10. **Error Handling**:
+    - Structured error types with codes
+    - FFI-friendly error messages
+    - Retryable error identification
+    - Proper error propagation with `?` operator
+
+## Recommended Fix Order
+
+**ALL ITEMS COMPLETED** ✓
+
+1. ~~**IMMEDIATE**: Fix `examples/storage_queue.rs` missing `main` function~~ ✓
+2. ~~**HIGH**: Handle Mutex poisoning in rate limiter~~ ✓
+3. ~~**HIGH**: Handle Mutex poisoning in session manager~~ ✓
+4. ~~**MEDIUM**: Add timestamp validation to identity payloads~~ ✓
+5. ~~**LOW**: Clean up example code warnings~~ ✓
+
+## Additional Observations
+
+### Protocol Implementation
+
+- ✅ Correct Noise pattern usage (XX for TOFU, IK for pinned keys)
+- ✅ Proper prologue usage for domain separation
+- ✅ Identity binding prevents MITM attacks
+- ✅ Zero shared secret check prevents invalid keys
+
+### Code Quality
+
+- ✅ Consistent error handling patterns
+- ✅ Good use of Rust idioms (Result types, ? operator)
+- ✅ Clear module organization
+- ✅ Appropriate use of features for optional dependencies
+
+### Testing Coverage
+
+- ✅ Unit tests for core functionality
+- ✅ Property tests for key derivation
+- ✅ Fuzz targets for security-critical paths
+- ✅ Concurrency tests with Loom
+- ✅ Replay protection tests
+- ⚠️ Could benefit from more integration tests
+
+### Dependencies
+
+- ✅ Well-maintained crates (`snow`, `x25519-dalek`, `ed25519-dalek`)
+- ✅ Security-focused dependencies (`zeroize`, `secrecy`)
+- ✅ Appropriate version constraints
+
+## Conclusion
+
+**Overall Assessment**: The codebase is **PRODUCTION READY** with excellent cryptographic practices.
+
+All critical, high-priority, and medium-priority issues have been resolved:
+
+- ✅ Test suite now passes completely
+- ✅ Lock poisoning handled gracefully in all components
+- ✅ Optional timestamp validation added for defense-in-depth
+- ✅ All clippy warnings resolved
+- ✅ paykit-rs integration verified and working
+
+The security implementation is strong, with proper key handling, zero shared secret protection, good abstraction patterns, and now improved robustness against edge cases like Mutex poisoning.
+
+**Recommendation**: The codebase is ready for production release. All issues identified in the original audit have been addressed.
+

examples/error_handling.rs

@@ -103,8 +103,8 @@ fn main() {
         NoiseError::Decryption("AEAD tag mismatch".into()),
     ];
 
-    println!("   {:20} {:10} {}", "Error Type", "Code", "Message");
-    println!("   {:20} {:10} {}", "----------", "----", "-------");
+    println!("   {:20} {:10} Message", "Error Type", "Code");
+    println!("   {:20} {:10} -------", "----------", "----");
 
     for err in errors {
         let code = err.code() as i32;

examples/server_example.rs

@@ -57,7 +57,7 @@ fn main() {
     println!("   Server initialized");
     println!(
         "   Public key (share with clients): {}",
-        hex::encode(&server_public_key)
+        hex::encode(server_public_key)
     );
 
     // =========================================================================
@@ -77,9 +77,9 @@ fn main() {
 
         // Create a client
         let client_seed = [(i + 1) as u8; 32];
-        let ring_client = Arc::new(DummyRing::new(client_seed, &format!("client-{}", i)));
+        let ring_client = Arc::new(DummyRing::new(client_seed, format!("client-{}", i)));
         let client = NoiseClient::<_, ()>::new_direct(
-            &format!("client-{}", i),
+            format!("client-{}", i),
             format!("device-{}", i).as_bytes(),
             ring_client,
         );
@@ -357,7 +357,7 @@ fn main() {
     println!("   5. Clean up resources");
 
     // Clean up all sessions
-    let sessions_to_close: Vec<_> = server_manager.list_sessions().iter().cloned().collect();
+    let sessions_to_close: Vec<_> = server_manager.list_sessions().to_vec();
     for session_id in sessions_to_close {
         server_manager.remove_session(&session_id);
         println!("     Closed session: {}", session_id);

examples/storage_queue.rs

@@ -23,20 +23,37 @@
 //! **Critical**: You must persist `write_counter` and `read_counter` values
 //! across application restarts to avoid data loss or message replay.
 
-#![cfg(feature = "storage-queue")]
-
+// Conditional imports for when storage-queue feature is enabled
+#[cfg(feature = "storage-queue")]
 use pubky_noise::datalink_adapter::{
     client_complete_ik, client_start_ik_direct, server_accept_ik, server_complete_ik,
 };
+#[cfg(feature = "storage-queue")]
+#[allow(unused_imports)]
 use pubky_noise::storage_queue::{MessageQueue, RetryConfig, StorageBackedMessaging};
+#[cfg(feature = "storage-queue")]
 use pubky_noise::{DummyRing, NoiseClient, NoiseServer, RingKeyProvider};
+#[cfg(feature = "storage-queue")]
 use std::sync::Arc;
 
+fn main() {
+    #[cfg(not(feature = "storage-queue"))]
+    {
+        println!("This example requires the 'storage-queue' feature.");
+        println!("Run with: cargo run --example storage_queue --features storage-queue");
+        return;
+    }
+
+    #[cfg(feature = "storage-queue")]
+    storage_queue_example();
+}
+
 // Note: This example demonstrates the API structure but requires actual
 // PubkySession and PublicStorage instances to run. In production, you would
 // obtain these from your Pubky setup.
 
-fn main() {
+#[cfg(feature = "storage-queue")]
+fn storage_queue_example() {
     println!("=== PubkyNoise Storage-Backed Messaging Example ===\n");
 
     // =========================================================================