chore!: audit fixes

[tac0turtle]

Overview

[claude]

Claude finished @tac0turtle's task —— View job

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Code Review Complete

I've performed a comprehensive code review of the audit fixes PR. Below are my findings organized by the focus areas requested.

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1. Code Quality & Architecture

✅ Strengths

• Clean error handling pattern: The introduction of common.ErrOversizedItem as an unrecoverable error type enables graceful halts rather than live-lock situations (block/internal/common/errors.go:22)
• Separation of concerns: The split between DA submission (da_submitter.go) and processing (submitter.go) is well-architected
• Exponential backoff with clamping: reaper.go:100-131 implements a robust backoff strategy with failure tracking

⚠️ Concerns

1. Test Coverage is Critically Low (28%)

The Codecov report shows 144 lines of missing coverage with several files having 0-16% patch coverage:

• block/internal/submitting/submitter.go: 0% (23 lines missing)
• block/internal/submitting/da_submitter.go: 0% (12 lines missing)
• block/internal/reaping/reaper.go: 14.28% (29 lines missing)
• block/internal/executing/executor.go: 11.76% (15 lines missing)

Critical paths with no test coverage:

• sendCriticalError() functions across multiple components
• DA submission halting logic (submitter.go:162-170, 184-192)
• Executor halt on permanent validation errors (executor.go:284-292, 302-309)
• Retry logic with exponential backoff

Recommendation: Add unit tests for error handling paths, especially:

• Mock tests for ErrOversizedItem triggering halt behavior
• Retry backoff validation tests
• Critical error channel behavior tests

2. Context Handling in da_submitter.go:401-402

submitCtx, cancel := context.WithTimeout(ctx, submissionTimeout)
defer cancel()

The defer cancel() is placed immediately after creation, but the function continues in a retry loop. If the loop runs long, this could lead to resource leaks. Consider moving the cancel to execute after the submission result is processed:

submitCtx, cancel := context.WithTimeout(ctx, submissionTimeout)
res := types.SubmitWithHelpers(submitCtx, s.da, s.logger, marshaled, rs.GasPrice, namespace, options)
cancel() // Call immediately after submission completes

3. Magic Constants Need Documentation

• defaultMaxBlobSize = 1.5 * 1024 * 1024 appears in both executing/executor.go:27 and cmd/run_node.go:29 and submitting/da_submitter.go:28. Consider centralizing this in a config constant.
• MaxRetriesBeforeHalt referenced in submitter.go:272-274 but defined elsewhere—not immediately visible in the diff.

---

2. Error Handling & Resilience

✅ Strengths

1. Robust Halt Mechanisms for Unrecoverable Errors

The PR introduces proper halt logic for critical failures:

• ErrOversizedItem in submitter.go:162-170, 184-192 triggers immediate shutdown
• Permanent block validation errors halt executor (executor.go:284-292, 302-309)
• SetFinal failures with retry exhaustion trigger controlled shutdown (submitter.go:243-248)

2. Improved Retry Logic with Exponential Backoff

• reaper.go:100-131 implements capped exponential backoff with failure counter
• da_submitter.go includes sophisticated retry policy with gas price adjustment
• Proper use of context cancellation checks throughout

3. Critical Error Propagation

The errorCh chan<- error pattern in executor.go:60 and submitter.go:57 enables components to signal critical failures to the node orchestrator:

func (s *Submitter) sendCriticalError(err error) {
    if s.errorCh != nil {
        select {
        case s.errorCh <- err:
        default:
            // Channel full, error already reported
        }
    }
}

⚠️ Concerns

1. Silent Failure in Reaper (reaper.go:197-200)

if err := r.seenStore.Put(r.ctx, key, []byte{1}); err != nil {
    // Log but don't fail on persistence errors
    r.logger.Error().Err(err).Str("txHash", txHash).Msg("failed to persist seen tx")
}

This could lead to transaction re-submission if the process restarts before the seenStore persists. While the comment acknowledges this, consider:

• Adding a metric to track persistence failures
• Implementing a background sync mechanism
• Or clarifying in documentation that restart may cause duplicate submissions

2. Inconsistent Error Wrapping

Some functions use fmt.Errorf("failed to...: %w", err) consistently, but others don't always include context:

• da_submitter.go:359: return err - loses context from marshalItems
• Consider standardized error wrapping across all return paths

3. Context Deadline Handling in P2P Handler

p2p_handler.go:59-68 uses 500ms timeout for GetByHeight:

timeoutCtx, cancel := context.WithTimeout(ctx, 500*time.Millisecond)
header, err := h.headerStore.GetByHeight(timeoutCtx, height)
cancel()

• The 500ms constant should be configurable or documented why this value was chosen
• Returning immediately on timeout prevents syncing subsequent heights—this could cause sync delays if network is slow

---

3. Security

✅ Strengths

1. DataHash Validation to Prevent Data Tampering

Critical security additions in multiple locations to prevent pairing legitimate headers with malicious data:

In p2p_handler.go:98-108:

// CRITICAL: Validate that data matches the header's DataHash commitment
// This prevents accepting legitimate headers paired with tampered data from different blocks
dataCommitment := data.DACommitment()
if !bytes.Equal(header.DataHash[:], dataCommitment[:]) {
    h.logger.Warn().
        Uint64("height", height).
        Str("header_data_hash", fmt.Sprintf("%x", header.DataHash)).
        Str("actual_data_hash", fmt.Sprintf("%x", dataCommitment)).
        Msg("DataHash mismatch: header and data do not match from P2P, discarding")
    continue
}

Also enforced in:

• p2p_handler.go:181-191 (ProcessDataRange)
• da_retriever.go:205-215 (processBlobs)

This is an excellent defense against block replacement attacks.

2. Enhanced Passphrase Security

In pkg/signer/file/local.go:

• Uses Argon2id for key derivation (line 417-423) instead of naive key stretching
• Implements zeroBytes() to wipe sensitive data from memory (line 442-444)
• defer zeroBytes(passphrase) throughout ensures passphrases don't linger
• File permissions set to 0600 for key files (local.go:232, 307)

3. Timestamp Validation

types/header.go:136-142 and types/data.go:141-146 validate timestamps aren't too far in the future (1 minute clock drift allowance), preventing timestamp manipulation attacks.

⚠️ Concerns

1. Proposer Address Validation

While proposer validation exists (p2p_handler.go:215-221, da_retriever.go:305-310), the comparison uses:

if string(proposerAddr) != string(r.genesis.ProposerAddress)

This converts byte slices to strings for comparison. While functionally correct, using bytes.Equal() would be more idiomatic and avoid unnecessary allocations. This is done correctly in other places (p2p_handler.go:216).

2. Passphrase File Handling in keys.go

keys.go:59 uses strings.TrimSpace(string(passphraseBytes)) which could leave the passphrase in memory. Consider:

passphrase := strings.TrimSpace(string(passphraseBytes))
defer zeroBytes([]byte(passphrase)) // Wipe after use

However, this won't work perfectly since Go strings are immutable. The current approach is acceptable but document this limitation.

3. No Rate Limiting on P2P Gossip

p2p_handler.go processes headers/data from peers without apparent rate limiting. A malicious peer could flood with invalid blocks. Consider adding:

• Per-peer rate limits
• Reputation scoring for peers sending invalid data
• Exponential backoff for peers triggering validation errors

---

4. Performance & Resource Efficiency

✅ Strengths

1. Concurrent Marshaling with Semaphore

da_submitter.go:526-551 uses a semaphore pattern to limit concurrency:

sem := make(chan struct{}, 32)

This prevents unbounded goroutine spawning while maintaining parallelism.

2. Efficient Batch Size Limiting

da_submitter.go:488-511 limitBatchBySize() implements linear scan to fit items within blob limits, avoiding expensive binary search for this use case.

3. Lazy Mode Optimization

executor.go:262-268, 276-280 implements lazy block production—only creating blocks when transactions are available, reducing unnecessary work.

⚠️ Concerns

1. Unbounded Retry Loops

da_submitter.go:390-486 has a retry loop controlled by pol.MaxAttempts, but if this is set high (or unbounded), and context doesn't cancel, this could run indefinitely.

Verify MaxSubmitAttempts has a reasonable default cap in config validation.

2. Potential Goroutine Leak in Submitter

submitter.go:158-174, 180-196 spawn goroutines with TryLock():

if s.headerSubmissionMtx.TryLock() {
    go func() {
        defer s.headerSubmissionMtx.Unlock()
        // ...
    }()
}

If a goroutine panics before defer executes, the mutex remains locked. While Go's defer is panic-safe, consider adding panic recovery:

go func() {
    defer func() {
        if r := recover(); r != nil {
            s.logger.Error().Interface("panic", r).Msg("panic in header submission")
        }
        s.headerSubmissionMtx.Unlock()
    }()
    // ...
}()

3. In-Memory Cache Growth

da_retriever.go:57-58:

pendingHeaders map[uint64]*types.SignedHeader
pendingData    map[uint64]*types.Data

These are unbounded maps. If headers and data arrive out of sync for extended periods, memory could grow. Consider:

• Adding a max pending items limit
• Implementing TTL-based eviction
• Monitoring via metrics

---

5. Testing & Reliability

⚠️ Critical Issues

28% Patch Coverage is Unacceptable for Security-Critical Code

Given this PR is titled "audit fixes," the lack of tests for new error handling paths is concerning:

Missing Test Coverage for Critical Paths:

1. Halt Logic Testing (Priority: HIGH)

   • Test that ErrOversizedItem triggers proper shutdown
   • Test executor halt on permanent validation errors
   • Test submitter halt on SetFinal exhaustion
   • Verify error channels properly propagate failures

2. Retry and Backoff Logic (Priority: HIGH)

   • Test reaper exponential backoff (reaper.go:100-131)
   • Test DA submission retry with gas price adjustment
   • Test context cancellation during retries

3. Security Validations (Priority: HIGH)

   • Test DataHash mismatch detection in P2P handler
   • Test DataHash mismatch detection in DA retriever
   • Test timestamp validation (too far in future)
   • Test proposer address validation

4. Edge Cases (Priority: MEDIUM)

   • Test empty transaction handling
   • Test single oversized item error path
   • Test partial batch submission success
   • Test concurrent access to seen store in reaper

Specific Test Recommendations:

// Example test structure for reaper.go
func TestReaperExponentialBackoff(t *testing.T) {
    // Test that consecutive failures increase backoff exponentially
    // Test that backoff caps at MaxBackoffInterval
    // Test that success resets backoff
}

func TestReaperSeenStoreFallback(t *testing.T) {
    // Test behavior when seenStore.Put fails
    // Verify logging occurs
    // Verify transactions still submitted despite persistence failure
}

func TestSubmitterCriticalErrorHalt(t *testing.T) {
    // Test ErrOversizedItem triggers halt
    // Verify errorCh receives error
    // Verify context cancellation occurs
}

Test Quality Concerns in Existing Tests:

Looking at the changed test files:

• reaper_test.go: Changes mock expectations but doesn't add tests for new backoff logic
• submitter_test.go: Only changes mock call counts, no new test cases
• E2E tests updated but don't specifically validate audit fix behaviors

---

6. Documentation & Developer Experience

✅ Strengths

1. Excellent inline comments for security-critical code:

• p2p_handler.go:98-100: Clear explanation of DataHash validation
• submitter.go:327-334: Documents sequencer height to DA height mapping purpose
• keys.go:32-37: Strong warnings about key export security

2. Structured error messages with context:

s.logger.Error().Err(err).
    Msg("CRITICAL: Header exceeds DA blob size limit - halting to prevent live lock")

⚠️ Concerns

1. Missing Package-Level Documentation

Files like da_submitter.go, submitter.go, reaper.go lack package-level comments explaining:

• Overall responsibility
• Lifecycle management
• Threading model
• Error handling philosophy

2. Undocumented Configuration Changes

• No documentation on what MaxPendingHeadersAndData does (executor.go:335-346)
• LazyMode and LazyBlockInterval configuration lack clear usage docs
• DA retry policy parameters need explanation in config structs

3. Migration Guide Missing

For the passphrase file changes (keys.go, run_node.go), operators need:

• Instructions on creating passphrase files
• Security best practices (file permissions, storage)
• Migration path from old key storage (if applicable)

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Summary & Recommendations

Critical Issues (Fix Before Merge)

1. Add comprehensive tests for error handling paths to bring coverage above 60%
2. Fix context handling in da_submitter.go retry loop (cancel after each submission)
3. Add bounded size limits to pendingHeaders/pendingData maps in da_retriever.go
4. Add panic recovery to goroutines in submitter.go

High Priority Improvements

1. Add metrics for seenStore persistence failures in reaper
2. Centralize defaultMaxBlobSize constant
3. Make P2P timeout (500ms) configurable
4. Add rate limiting for P2P gossip
5. Document configuration parameters

Architectural Strengths

• Excellent halt mechanisms for unrecoverable errors
• Strong data integrity validation (DataHash checks)
• Improved cryptographic key management
• Well-structured error propagation via error channels

Overall Assessment

The audit fixes demonstrate strong architectural improvements for error resilience and security, particularly:

• Preventing live-lock scenarios with proper halts
• Defending against data tampering attacks
• Enhanced key security with Argon2

However, the critically low test coverage (28%) is a major concern for production readiness. The error handling paths introduced—which are the primary purpose of this audit fix PR—are largely untested.

Recommendation: Do not merge until test coverage reaches at least 60% with specific focus on the new error handling, retry logic, and security validation paths.

---

[github-actions]

The latest Buf updates on your PR. Results from workflow CI and Release / buf-check (pull_request).

Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	⏩ skipped	✅ passed	✅ passed	Oct 20, 2025, 2:56 PM

[codecov]

Codecov Report

❌ Patch coverage is 27.86070% with 145 lines in your changes missing coverage. Please review.
✅ Project coverage is 60.46%. Comparing base (0dba4e7) to head (a717df6).

Files with missing lines	Patch %	Lines
block/internal/reaping/reaper.go	13.88%	30 Missing and 1 partial ⚠️
block/internal/submitting/submitter.go	0.00%	23 Missing ⚠️
block/internal/executing/executor.go	11.76%	15 Missing ⚠️
block/internal/syncing/p2p_handler.go	16.66%	14 Missing and 1 partial ⚠️
types/data.go	16.66%	10 Missing and 5 partials ⚠️
block/internal/submitting/da_submitter.go	0.00%	12 Missing ⚠️
pkg/cmd/keys.go	61.53%	8 Missing and 2 partials ⚠️
pkg/cmd/run_node.go	33.33%	7 Missing and 3 partials ⚠️
block/internal/syncing/da_retriever.go	12.50%	6 Missing and 1 partial ⚠️
types/header.go	22.22%	5 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2764      +/-   ##
==========================================
- Coverage   61.26%   60.46%   -0.81%     
==========================================
  Files          81       81              
  Lines        8589     8744     +155     
==========================================
+ Hits         5262     5287      +25     
- Misses       2830     2943     +113     
- Partials      497      514      +17     

Flag	Coverage Δ
combined	60.46% <27.86%> (-0.81%)	⬇️

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