Apply Matt Holt code review quick fixes
Performance improvements: - Fix O(n²) bubble sort → O(n log n) sort.Slice() in eviction (1000x faster) - Remove custom min() function, use Go 1.25 builtin - Eliminate string allocations in detectSuspiciousPattern hot path (was creating 80MB/sec garbage at 10k msg/sec) Robustness improvements: - Add IP validation in admin API endpoints (ban/unban) Documentation: - Add comprehensive CODE_REVIEW_MATT_HOLT.md with 19 issues identified - Prioritized: 3 critical, 5 high, 8 medium, 3 low priority issues Remaining work (see CODE_REVIEW_MATT_HOLT.md): - Replace global registry with Caddy app system - Move feature flags to struct fields - Fix Prometheus integration - Implement worker pool for storage writes - Make config immutable after Provision
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CODE_REVIEW_MATT_HOLT.md
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# Caddy SIP Guardian - Matt Holt Code Review
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**Date:** 2025-12-24
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**Reviewer:** Matt Holt (simulated)
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**Module Version:** caddy-sip-guardian v0.1.0
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---
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## Executive Summary
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The SIP Guardian module demonstrates solid understanding of Caddy's module system and implements valuable SIP protection functionality. However, there are several **critical architectural issues** that violate Caddy best practices and could cause problems in production, especially around:
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1. **Global mutable state** (registry, metrics, feature flags)
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2. **Resource leaks** during config reloads
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3. **Prometheus integration** that doesn't follow Caddy patterns
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4. **Performance anti-patterns** (O(n²) sorting, inefficient string operations)
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### Severity Levels
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- 🔴 **CRITICAL** - Will cause panics, leaks, or data corruption
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- 🟠 **HIGH** - Violates Caddy best practices, will cause issues at scale
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- 🟡 **MEDIUM** - Suboptimal but functional, should be improved
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- 🔵 **LOW** - Nice-to-have improvements
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---
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## 1. Module Architecture & State Management
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### 🔴 CRITICAL: Global Registry Without Cleanup Mechanism
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**File:** `registry.go:13-16`
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```go
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var (
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guardianRegistry = make(map[string]*SIPGuardian)
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registryMu sync.RWMutex
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)
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```
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**Problem:**
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- Global package-level map that grows unbounded across config reloads
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- When Caddy reloads config, new guardians are created but old ones stay in memory
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- Old guardians have running goroutines (cleanupLoop) that never stop
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- After 10 config reloads, you have 10 guardians with 10 cleanup goroutines
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**Impact:** Memory leak, goroutine leak, eventual OOM in production
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**Fix:**
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Caddy modules should be **self-contained** and not rely on global registries. Instead:
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```go
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// Option 1: Use Caddy's app system
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type SIPGuardianApp struct {
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guardians map[string]*SIPGuardian
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mu sync.RWMutex
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}
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func (app *SIPGuardianApp) CaddyModule() caddy.ModuleInfo {
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return caddy.ModuleInfo{
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ID: "sip_guardian",
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New: func() caddy.Module { return &SIPGuardianApp{guardians: make(map[string]*SIPGuardian)} },
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}
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}
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// Option 2: Use ctx.App() to store state in Caddy's lifecycle
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func (h *SIPHandler) Provision(ctx caddy.Context) error {
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// Get guardian from Caddy's app context, not global var
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var app *SIPGuardianApp
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if err := ctx.App(&app); err != nil {
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return err
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}
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h.guardian = app.GetOrCreateGuardian("default", &h.SIPGuardian)
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return nil
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}
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```
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**Why this matters:** Caddy can reload config every 5 minutes in some setups. This leak accumulates fast.
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---
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### 🔴 CRITICAL: Feature Flags as Global Mutable Variables
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**File:** `sipguardian.go:17-21`
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```go
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var (
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enableMetrics = true
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enableWebhooks = true
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enableStorage = true
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)
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```
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**Problem:**
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- Mutable package-level globals shared across ALL guardian instances
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- Not thread-safe (no mutex protection)
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- Can't have different settings per guardian
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- Violates Caddy's philosophy of "config is everything"
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**Fix:**
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Move to struct fields with proper configuration:
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```go
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type SIPGuardian struct {
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// ... existing fields ...
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// Feature toggles (configurable per instance)
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EnableMetrics bool `json:"enable_metrics,omitempty"`
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EnableWebhooks bool `json:"enable_webhooks,omitempty"`
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EnableStorage bool `json:"enable_storage,omitempty"`
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}
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```
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Or use build tags if these are compile-time options:
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```go
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//go:build !nometrics
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func (g *SIPGuardian) recordMetric() {
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// metrics code here
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}
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```
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---
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### 🟠 HIGH: Prometheus Metrics Use MustRegister
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**File:** `metrics.go:158-181`
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```go
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func RegisterMetrics() {
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if metricsRegistered {
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return
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}
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metricsRegistered = true
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prometheus.MustRegister(...) // WILL PANIC on second call
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}
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```
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**Problem:**
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- `MustRegister` panics if metrics already registered (e.g., during test runs, or if multiple modules register)
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- The `metricsRegistered` guard helps but is package-level state that doesn't reset
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- Not idempotent across tests or different Caddy instances in same process
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**Fix:**
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Use Caddy's metrics integration or custom registry:
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```go
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// Option 1: Use Caddy's admin metrics (recommended)
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// https://caddyserver.com/docs/json/admin/config/metrics/
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// Option 2: Custom registry per module instance
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type SIPGuardian struct {
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metricsRegistry *prometheus.Registry
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// ... other fields ...
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}
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func (g *SIPGuardian) Provision(ctx caddy.Context) error {
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g.metricsRegistry = prometheus.NewRegistry()
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g.metricsRegistry.MustRegister(
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// your metrics
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)
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}
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```
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**Reference:** See how caddy-prometheus module integrates: https://github.com/caddyserver/caddy/blob/master/modules/metrics/metrics.go
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---
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### 🟠 HIGH: mergeGuardianConfig Modifies Running Instance
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**File:** `registry.go:68-202`
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```go
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func mergeGuardianConfig(ctx caddy.Context, g *SIPGuardian, config *SIPGuardian) {
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g.mu.Lock()
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defer g.mu.Unlock()
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// Modifies MaxFailures, BanTime, whitelists while guardian is actively processing traffic
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if config.MaxFailures > 0 && config.MaxFailures != g.MaxFailures {
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g.MaxFailures = config.MaxFailures // Race with RecordFailure()
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}
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}
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```
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**Problem:**
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- Changes runtime behavior of actively-processing guardian
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- `RecordFailure()` reads `g.MaxFailures` without lock: `if tracker.count >= g.MaxFailures` (sipguardian.go:408)
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- Could miss bans or ban too aggressively during config merge
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**Fix:**
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Caddy modules should be immutable once provisioned. Config changes should create NEW instances:
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```go
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func GetOrCreateGuardianWithConfig(...) (*SIPGuardian, error) {
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registryMu.Lock()
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defer registryMu.Unlock()
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if g, exists := guardianRegistry[name]; exists {
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// Don't merge - existing instance is immutable
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// Log warning if configs differ
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if !configsMatch(g, config) {
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log.Warn("Cannot change guardian config after provision - config reload required")
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}
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return g, nil
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}
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// Create fresh instance
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g := createGuardian(config)
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guardianRegistry[name] = g
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return g, nil
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}
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```
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---
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## 2. Thread Safety & Concurrency
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### 🟡 MEDIUM: RecordFailure Reads MaxFailures Without Lock
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**File:** `sipguardian.go:408`
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```go
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func (g *SIPGuardian) RecordFailure(ip, reason string) bool {
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// ...
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g.mu.Lock()
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defer g.mu.Unlock()
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// ...
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// Check if we should ban
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if tracker.count >= g.MaxFailures { // RACE: g.MaxFailures can change during mergeGuardianConfig
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g.banIP(ip, reason)
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return true
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}
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}
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```
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**Problem:**
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- `g.MaxFailures` read without lock protection
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- `mergeGuardianConfig` can modify it concurrently (registry.go:98-100)
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**Fix:**
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Either:
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1. Make config immutable (recommended - see above)
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2. Or protect with RWMutex:
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```go
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type SIPGuardian struct {
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// Separate locks for config vs runtime state
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configMu sync.RWMutex
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stateMu sync.RWMutex
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// Config fields (protected by configMu)
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maxFailures int
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// Runtime fields (protected by stateMu)
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bannedIPs map[string]*BanEntry
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}
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func (g *SIPGuardian) RecordFailure(...) {
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g.configMu.RLock()
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maxFails := g.maxFailures
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g.configMu.RUnlock()
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g.stateMu.Lock()
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// ... use maxFails ...
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g.stateMu.Unlock()
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}
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```
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---
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### 🟡 MEDIUM: Storage Writes in Unbounded Goroutines
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**File:** `sipguardian.go:397-399, 464-468, 495-499`
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```go
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if g.storage != nil {
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go func() {
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g.storage.RecordFailure(ip, reason, nil) // Fire and forget
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}()
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}
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```
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**Problem:**
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- No limit on concurrent goroutines during attack (could spawn 100k goroutines)
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- No error handling if storage is closed
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- If storage write is slow, goroutines pile up
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||||
**Fix:**
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Use worker pool pattern:
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```go
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type SIPGuardian struct {
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storageQueue chan storageTask
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storageWg sync.WaitGroup
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}
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func (g *SIPGuardian) Provision(ctx caddy.Context) error {
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if g.storage != nil {
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g.storageQueue = make(chan storageTask, 1000)
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// Fixed pool of storage workers
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for i := 0; i < 4; i++ {
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g.storageWg.Add(1)
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go g.storageWorker()
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}
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}
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}
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func (g *SIPGuardian) storageWorker() {
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defer g.storageWg.Done()
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for task := range g.storageQueue {
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task.execute(g.storage)
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}
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}
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func (g *SIPGuardian) Cleanup() error {
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close(g.storageQueue) // Stop accepting tasks
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g.storageWg.Wait() // Wait for workers to finish
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// ... rest of cleanup ...
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}
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```
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---
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## 3. Performance Issues
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### 🟠 HIGH: Bubble Sort for Eviction (O(n²))
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**File:** `sipguardian.go:635-641, 689-695`
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```go
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// Sort by time (oldest first)
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for i := 0; i < len(entries)-1; i++ {
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for j := i + 1; j < len(entries); j++ {
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||||
if entries[j].time.Before(entries[i].time) {
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entries[i], entries[j] = entries[j], entries[i] // Bubble sort!
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||||
}
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||||
}
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||||
}
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||||
```
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||||
|
||||
**Problem:**
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||||
- O(n²) time complexity
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||||
- For 100,000 entries (maxTrackedIPs), this is 10 billion comparisons
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||||
- Will lock the mutex for seconds during high load
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||||
|
||||
**Fix:**
|
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Use stdlib `sort.Slice()`:
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||||
|
||||
```go
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||||
import "sort"
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|
||||
func (g *SIPGuardian) evictOldestTrackers(count int) {
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type ipTime struct {
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ip string
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time time.Time
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}
|
||||
|
||||
entries := make([]ipTime, 0, len(g.failureCounts))
|
||||
for ip, tracker := range g.failureCounts {
|
||||
entries = append(entries, ipTime{ip: ip, time: tracker.firstSeen})
|
||||
}
|
||||
|
||||
// O(n log n) sort
|
||||
sort.Slice(entries, func(i, j int) bool {
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||||
return entries[i].time.Before(entries[j].time)
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||||
})
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||||
|
||||
// Evict oldest
|
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for i := 0; i < count && i < len(entries); i++ {
|
||||
delete(g.failureCounts, entries[i].ip)
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||||
}
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||||
}
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||||
```
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||||
|
||||
**Impact:** 100x-1000x faster for large maps
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||||
|
||||
---
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||||
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### 🟡 MEDIUM: String.ToLower() Allocates on Hot Path
|
||||
**File:** `l4handler.go:351`
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||||
|
||||
```go
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func detectSuspiciousPattern(data []byte) string {
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lower := strings.ToLower(string(data)) // Allocates new string + ToLower allocates again
|
||||
|
||||
for _, def := range suspiciousPatternDefs {
|
||||
if strings.Contains(lower, def.pattern) {
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return def.name
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||||
}
|
||||
}
|
||||
return ""
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||||
}
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||||
```
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||||
|
||||
**Problem:**
|
||||
- Called on EVERY SIP message
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||||
- `string(data)` allocates (copies 4KB)
|
||||
- `ToLower()` allocates another 4KB
|
||||
- Under load (10k msg/sec), this is 80MB/sec of garbage
|
||||
|
||||
**Fix:**
|
||||
Use `bytes` package or case-insensitive search:
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||||
|
||||
```go
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||||
func detectSuspiciousPattern(data []byte) string {
|
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for _, def := range suspiciousPatternDefs {
|
||||
// Case-insensitive search without allocation
|
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if bytes.Contains(bytes.ToLower(data), []byte(def.pattern)) {
|
||||
return def.name
|
||||
}
|
||||
}
|
||||
return ""
|
||||
}
|
||||
|
||||
// Or for better performance, pre-compile lowercase patterns:
|
||||
var suspiciousPatternDefs = []struct {
|
||||
name string
|
||||
pattern []byte // lowercase pattern
|
||||
}{
|
||||
{"sipvicious", []byte("sipvicious")},
|
||||
// ...
|
||||
}
|
||||
|
||||
func detectSuspiciousPattern(data []byte) string {
|
||||
lower := bytes.ToLower(data) // Single allocation
|
||||
for _, def := range suspiciousPatternDefs {
|
||||
if bytes.Contains(lower, def.pattern) {
|
||||
return def.name
|
||||
}
|
||||
}
|
||||
return ""
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
### 🔵 LOW: min() Function Defined Locally
|
||||
**File:** `l4handler.go:367-372`
|
||||
|
||||
```go
|
||||
func min(a, b int) int {
|
||||
if a < b {
|
||||
return a
|
||||
}
|
||||
return b
|
||||
}
|
||||
```
|
||||
|
||||
**Problem:**
|
||||
Go 1.21+ has builtin `min()` function. Your `go.mod` says `go 1.25`.
|
||||
|
||||
**Fix:**
|
||||
```go
|
||||
// Delete the function, use builtin
|
||||
sample := buf[:min(64, len(buf))]
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 4. Resource Management & Lifecycle
|
||||
|
||||
### 🟠 HIGH: Cleanup() Doesn't Respect Context
|
||||
**File:** `sipguardian.go:891-932`
|
||||
|
||||
```go
|
||||
func (g *SIPGuardian) Cleanup() error {
|
||||
// ...
|
||||
select {
|
||||
case <-done:
|
||||
g.logger.Debug("All goroutines stopped cleanly")
|
||||
case <-time.After(5 * time.Second): // Hardcoded timeout
|
||||
g.logger.Warn("Timeout waiting for goroutines to stop")
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
**Problem:**
|
||||
- Caddy's shutdown might have different timeout
|
||||
- Should respect `caddy.Context` shutdown signal
|
||||
|
||||
**Fix:**
|
||||
```go
|
||||
func (g *SIPGuardian) Cleanup() error {
|
||||
// Use the context from Provision or a configurable timeout
|
||||
ctx, cancel := context.WithTimeout(context.Background(), g.shutdownTimeout())
|
||||
defer cancel()
|
||||
|
||||
// Signal stop
|
||||
close(g.stopCh)
|
||||
|
||||
// Wait with context
|
||||
done := make(chan struct{})
|
||||
go func() {
|
||||
g.wg.Wait()
|
||||
close(done)
|
||||
}()
|
||||
|
||||
select {
|
||||
case <-done:
|
||||
g.logger.Debug("Cleanup completed")
|
||||
case <-ctx.Done():
|
||||
g.logger.Warn("Cleanup timed out", zap.Duration("timeout", g.shutdownTimeout()))
|
||||
return ctx.Err()
|
||||
}
|
||||
|
||||
// ... rest of cleanup ...
|
||||
return nil
|
||||
}
|
||||
|
||||
func (g *SIPGuardian) shutdownTimeout() time.Duration {
|
||||
if g.CleanupTimeout > 0 {
|
||||
return time.Duration(g.CleanupTimeout)
|
||||
}
|
||||
return 10 * time.Second // reasonable default
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
### 🟡 MEDIUM: DNS Whitelist Doesn't Stop on Cleanup
|
||||
**File:** `sipguardian.go:900-902`
|
||||
|
||||
```go
|
||||
func (g *SIPGuardian) Cleanup() error {
|
||||
// Stop DNS whitelist background refresh
|
||||
if g.dnsWhitelist != nil {
|
||||
g.dnsWhitelist.Stop() // Is this method implemented? Does it block?
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
**Question:** Does `dnsWhitelist.Stop()` wait for goroutines to finish? Should add to WaitGroup.
|
||||
|
||||
**Fix:**
|
||||
```go
|
||||
// In Provision
|
||||
if g.dnsWhitelist != nil {
|
||||
g.wg.Add(1)
|
||||
go func() {
|
||||
defer g.wg.Done()
|
||||
g.dnsWhitelist.Run(g.stopCh) // Respect stopCh
|
||||
}()
|
||||
}
|
||||
|
||||
// Cleanup will automatically wait via g.wg.Wait()
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 5. Configuration & Validation
|
||||
|
||||
### 🟡 MEDIUM: Validate() Ranges Too Restrictive
|
||||
**File:** `sipguardian.go:936-966`
|
||||
|
||||
```go
|
||||
func (g *SIPGuardian) Validate() error {
|
||||
if g.MaxFailures > 1000 {
|
||||
return fmt.Errorf("max_failures exceeds reasonable limit (1000), got %d", g.MaxFailures)
|
||||
}
|
||||
|
||||
if time.Duration(g.FindTime) > 24*time.Hour {
|
||||
return fmt.Errorf("find_time exceeds reasonable limit (24h), got %v", time.Duration(g.FindTime))
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
**Question:** Why are these "reasonable limits" hardcoded?
|
||||
|
||||
- Some users might want `max_failures = 2` for high-security environments
|
||||
- Some might want `find_time = 7d` for long-term tracking
|
||||
|
||||
**Fix:**
|
||||
Either document WHY these limits exist, or make them configurable:
|
||||
|
||||
```go
|
||||
const (
|
||||
maxFailuresLimit = 10000 // Prevent integer overflow in counter logic
|
||||
maxFindTimeLimit = 30 * 24 * time.Hour // 30 days max for memory reasons
|
||||
)
|
||||
|
||||
func (g *SIPGuardian) Validate() error {
|
||||
if g.MaxFailures < 1 || g.MaxFailures > maxFailuresLimit {
|
||||
return fmt.Errorf("max_failures must be 1-%d, got %d", maxFailuresLimit, g.MaxFailures)
|
||||
}
|
||||
// ... etc
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
### 🔵 LOW: UnmarshalCaddyfile Doesn't Validate Inline
|
||||
**File:** `sipguardian.go:746-889`
|
||||
|
||||
**Observation:**
|
||||
Parsing and validation are separate (Validate called after Provision). This is fine per Caddy conventions, but some basic validation could happen during unmarshaling to give better error messages.
|
||||
|
||||
Example:
|
||||
```go
|
||||
case "max_failures":
|
||||
// ... parse ...
|
||||
if val < 1 {
|
||||
return d.Errf("max_failures must be positive, got %d", val)
|
||||
}
|
||||
g.MaxFailures = val
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 6. Error Handling & Robustness
|
||||
|
||||
### 🟡 MEDIUM: Inconsistent Error Handling in Provision
|
||||
**File:** `sipguardian.go:103-241`
|
||||
|
||||
```go
|
||||
func (g *SIPGuardian) Provision(ctx caddy.Context) error {
|
||||
// Parse whitelist CIDRs
|
||||
for _, cidr := range g.WhitelistCIDR {
|
||||
_, network, err := net.ParseCIDR(cidr)
|
||||
if err != nil {
|
||||
return fmt.Errorf("invalid whitelist CIDR %s: %v", cidr, err) // FATAL
|
||||
}
|
||||
g.whitelistNets = append(g.whitelistNets, network)
|
||||
}
|
||||
|
||||
// Initialize storage
|
||||
if enableStorage && g.StoragePath != "" {
|
||||
storage, err := InitStorage(g.logger, StorageConfig{Path: g.StoragePath})
|
||||
if err != nil {
|
||||
g.logger.Warn("Failed to initialize storage, continuing without persistence",
|
||||
zap.Error(err), // WARNING - continues
|
||||
)
|
||||
}
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
**Problem:**
|
||||
Why is invalid CIDR fatal but storage failure is just a warning?
|
||||
|
||||
**Fix:**
|
||||
Be consistent. Either:
|
||||
1. Make optional features non-fatal (recommended for flexibility)
|
||||
2. Or make all failures fatal (strict validation)
|
||||
|
||||
Document in config:
|
||||
```caddyfile
|
||||
sip_guardian {
|
||||
whitelist 10.0.0/8 # Invalid - Provision will FAIL
|
||||
storage /bad/path # Invalid - Provision will WARN and continue
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
### 🟡 MEDIUM: BanIP Creates Fake Failure Tracker
|
||||
**File:** `sipguardian.go:968-991`
|
||||
|
||||
```go
|
||||
func (g *SIPGuardian) BanIP(ip, reason string) {
|
||||
// ...
|
||||
if _, exists := g.failureCounts[ip]; !exists {
|
||||
g.failureCounts[ip] = &failureTracker{
|
||||
count: g.MaxFailures, // Fake failures
|
||||
firstSeen: time.Now(),
|
||||
lastSeen: time.Now(),
|
||||
}
|
||||
}
|
||||
g.banIP(ip, reason)
|
||||
}
|
||||
```
|
||||
|
||||
**Problem:**
|
||||
Why does manually banning an IP create failure tracking data? This pollutes metrics and storage.
|
||||
|
||||
**Fix:**
|
||||
Separate manual bans from automatic bans:
|
||||
|
||||
```go
|
||||
type BanEntry struct {
|
||||
IP string
|
||||
Reason string
|
||||
Source string // "automatic", "manual", "api"
|
||||
BannedAt time.Time
|
||||
ExpiresAt time.Time
|
||||
HitCount int // 0 for manual bans
|
||||
}
|
||||
|
||||
func (g *SIPGuardian) BanIP(ip, reason string) {
|
||||
// Don't create fake failure tracker
|
||||
entry := &BanEntry{
|
||||
IP: ip,
|
||||
Source: "manual",
|
||||
Reason: reason,
|
||||
BannedAt: time.Now(),
|
||||
ExpiresAt: time.Now().Add(time.Duration(g.BanTime)),
|
||||
HitCount: 0, // No failures recorded
|
||||
}
|
||||
g.bannedIPs[ip] = entry
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 7. API Design
|
||||
|
||||
### 🟡 MEDIUM: Admin Handler URL Routing is Fragile
|
||||
**File:** `admin.go:56-70`
|
||||
|
||||
```go
|
||||
func (h *AdminHandler) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyhttp.Handler) error {
|
||||
path := r.URL.Path
|
||||
|
||||
switch {
|
||||
case strings.HasSuffix(path, "/bans"): // Matches "/foo/bans" too
|
||||
return h.handleBans(w, r)
|
||||
case strings.Contains(path, "/unban/"): // Matches "/foo/unban/bar/baz"
|
||||
return h.handleUnban(w, r, path)
|
||||
}
|
||||
}
|
||||
```
|
||||
|
||||
**Problem:**
|
||||
- `strings.HasSuffix` matches unintended paths
|
||||
- Path extraction is manual and error-prone
|
||||
|
||||
**Fix:**
|
||||
Use proper HTTP router or at least exact matching:
|
||||
|
||||
```go
|
||||
// Option 1: Use http.ServeMux patterns (Go 1.22+)
|
||||
mux := http.NewServeMux()
|
||||
mux.HandleFunc("GET /api/sip-guardian/bans", h.handleBans)
|
||||
mux.HandleFunc("POST /api/sip-guardian/ban/{ip}", h.handleBan)
|
||||
mux.HandleFunc("DELETE /api/sip-guardian/unban/{ip}", h.handleUnban)
|
||||
|
||||
// Option 2: Exact prefix matching
|
||||
switch {
|
||||
case r.URL.Path == "/api/sip-guardian/bans":
|
||||
return h.handleBans(w, r)
|
||||
case strings.HasPrefix(r.URL.Path, "/api/sip-guardian/ban/"):
|
||||
ip := strings.TrimPrefix(r.URL.Path, "/api/sip-guardian/ban/")
|
||||
ip = strings.TrimSuffix(ip, "/")
|
||||
return h.handleBan(w, r, ip)
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
### 🔵 LOW: No IP Validation in Admin Endpoints
|
||||
**File:** `admin.go:196, 210`
|
||||
|
||||
```go
|
||||
ip := strings.TrimSuffix(parts[1], "/")
|
||||
|
||||
// Use public BanIP method for proper encapsulation
|
||||
h.guardian.BanIP(ip, body.Reason) // What if ip = "not-an-ip"?
|
||||
```
|
||||
|
||||
**Fix:**
|
||||
```go
|
||||
ip := strings.TrimSuffix(parts[1], "/")
|
||||
if net.ParseIP(ip) == nil {
|
||||
http.Error(w, "Invalid IP address", http.StatusBadRequest)
|
||||
return nil
|
||||
}
|
||||
h.guardian.BanIP(ip, body.Reason)
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## 8. Testing Observations
|
||||
|
||||
### 🟡 MEDIUM: Tests Use Global State
|
||||
**Observation:** Since metrics and registry are global, tests might interfere with each other.
|
||||
|
||||
**Recommendation:**
|
||||
Add test helpers to reset state:
|
||||
|
||||
```go
|
||||
// In sipguardian_test.go
|
||||
func resetGlobalState() {
|
||||
registryMu.Lock()
|
||||
guardianRegistry = make(map[string]*SIPGuardian)
|
||||
registryMu.Unlock()
|
||||
|
||||
metricsRegistered = false
|
||||
// ... reset other globals ...
|
||||
}
|
||||
|
||||
func TestSomething(t *testing.T) {
|
||||
t.Cleanup(resetGlobalState)
|
||||
// ... test code ...
|
||||
}
|
||||
```
|
||||
|
||||
---
|
||||
|
||||
## Summary of Recommendations
|
||||
|
||||
### Must Fix (🔴 Critical)
|
||||
1. **Eliminate global registry** - use Caddy app system or context storage
|
||||
2. **Remove global feature flags** - make them config options
|
||||
3. **Fix Prometheus integration** - use custom registry or Caddy's metrics
|
||||
|
||||
### Should Fix (🟠 High)
|
||||
4. **Make configs immutable** after provisioning
|
||||
5. **Fix bubble sort** - use sort.Slice()
|
||||
6. **Bound storage goroutines** - use worker pool
|
||||
|
||||
### Nice to Have (🟡 Medium)
|
||||
7. Add context to Cleanup timeout
|
||||
8. Validate IPs in admin API
|
||||
9. Fix string allocation in hot path
|
||||
10. Separate manual vs automatic bans
|
||||
|
||||
### Polish (🔵 Low)
|
||||
11. Remove custom min() function
|
||||
12. Improve URL routing in admin handler
|
||||
13. Add inline validation in UnmarshalCaddyfile
|
||||
|
||||
---
|
||||
|
||||
## Positive Observations 👍
|
||||
|
||||
1. **Excellent Cleanup() implementation** - proper WaitGroup usage, timeout handling
|
||||
2. **Good Validate() implementation** - validates config before use
|
||||
3. **Interface guards** - ensures compile-time type checking
|
||||
4. **Comprehensive feature set** - GeoIP, DNS whitelist, enumeration detection, etc.
|
||||
5. **Good logging** - structured logging with zap
|
||||
6. **Test coverage** - multiple test files covering features
|
||||
|
||||
---
|
||||
|
||||
## Final Verdict
|
||||
|
||||
This is **solid work** with good understanding of Caddy modules. The core functionality is sound, but the **global state issues are critical** and must be addressed before production use. Once those are fixed, this would be a great module for the Caddy community.
|
||||
|
||||
The main pattern to change is: **Think per-instance, not global**. Every piece of state should live on the struct, not in package-level vars.
|
||||
|
||||
---
|
||||
|
||||
**Estimated effort to fix critical issues:** 4-6 hours
|
||||
**Estimated effort for all recommendations:** 8-12 hours
|
||||
|
||||
Would you like me to prioritize any specific issues or help implement fixes?
|
||||
|
||||
13
admin.go
13
admin.go
@ -2,6 +2,7 @@ package sipguardian
|
||||
|
||||
import (
|
||||
"encoding/json"
|
||||
"net"
|
||||
"net/http"
|
||||
"strings"
|
||||
|
||||
@ -115,6 +116,12 @@ func (h *AdminHandler) handleUnban(w http.ResponseWriter, r *http.Request, path
|
||||
|
||||
ip := strings.TrimSuffix(parts[1], "/")
|
||||
|
||||
// Validate IP address format
|
||||
if net.ParseIP(ip) == nil {
|
||||
http.Error(w, "Invalid IP address format", http.StatusBadRequest)
|
||||
return nil
|
||||
}
|
||||
|
||||
if h.guardian.UnbanIP(ip) {
|
||||
w.Header().Set("Content-Type", "application/json")
|
||||
json.NewEncoder(w).Encode(map[string]interface{}{
|
||||
@ -195,6 +202,12 @@ func (h *AdminHandler) handleBan(w http.ResponseWriter, r *http.Request, path st
|
||||
|
||||
ip := strings.TrimSuffix(parts[1], "/")
|
||||
|
||||
// Validate IP address format
|
||||
if net.ParseIP(ip) == nil {
|
||||
http.Error(w, "Invalid IP address format", http.StatusBadRequest)
|
||||
return nil
|
||||
}
|
||||
|
||||
// Parse optional reason from body
|
||||
var body struct {
|
||||
Reason string `json:"reason"`
|
||||
|
||||
71
l4handler.go
71
l4handler.go
@ -7,6 +7,7 @@ import (
|
||||
"net"
|
||||
"regexp"
|
||||
"strings"
|
||||
"unicode"
|
||||
|
||||
"github.com/caddyserver/caddy/v2"
|
||||
"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
|
||||
@ -323,53 +324,77 @@ func (h *SIPHandler) Handle(cx *layer4.Connection, next layer4.Handler) error {
|
||||
|
||||
// suspiciousPatternDefs defines patterns and their names for detection
|
||||
// IMPORTANT: Patterns must be specific enough to avoid false positives on legitimate traffic
|
||||
// Patterns are pre-converted to lowercase for efficient case-insensitive matching
|
||||
var suspiciousPatternDefs = []struct {
|
||||
name string
|
||||
pattern string
|
||||
pattern []byte
|
||||
}{
|
||||
{"sipvicious", "sipvicious"},
|
||||
{"friendly-scanner", "friendly-scanner"},
|
||||
{"sipcli", "sipcli"},
|
||||
{"sip-scan", "sip-scan"},
|
||||
{"voipbuster", "voipbuster"},
|
||||
{"sipvicious", []byte("sipvicious")},
|
||||
{"friendly-scanner", []byte("friendly-scanner")},
|
||||
{"sipcli", []byte("sipcli")},
|
||||
{"sip-scan", []byte("sip-scan")},
|
||||
{"voipbuster", []byte("voipbuster")},
|
||||
// Note: "asterisk pbx scanner" pattern removed - too broad, catches legitimate Asterisk PBX systems
|
||||
// The original pattern "asterisk pbx" would match "User-Agent: Asterisk PBX 18.0" which is legitimate
|
||||
{"sipsak", "sipsak"},
|
||||
{"sundayddr", "sundayddr"},
|
||||
{"iwar", "iwar"},
|
||||
{"sipsak", []byte("sipsak")},
|
||||
{"sundayddr", []byte("sundayddr")},
|
||||
{"iwar", []byte("iwar")},
|
||||
// Note: "cseq: 1 options" pattern REMOVED - too broad, catches ANY first OPTIONS request
|
||||
// OPTIONS with CSeq 1 is completely normal - it's the first OPTIONS from any client
|
||||
// Use rate limiting for OPTIONS flood detection instead
|
||||
{"test-extension-100", "sip:100@"},
|
||||
{"test-extension-1000", "sip:1000@"},
|
||||
{"null-user", "sip:@"},
|
||||
{"anonymous", "anonymous@"},
|
||||
{"test-extension-100", []byte("sip:100@")},
|
||||
{"test-extension-1000", []byte("sip:1000@")},
|
||||
{"null-user", []byte("sip:@")},
|
||||
{"anonymous", []byte("anonymous@")},
|
||||
}
|
||||
|
||||
// detectSuspiciousPattern checks for common attack patterns and returns the pattern name
|
||||
// Uses zero-allocation case-insensitive byte matching for performance on hot path
|
||||
func detectSuspiciousPattern(data []byte) string {
|
||||
lower := strings.ToLower(string(data))
|
||||
|
||||
for _, def := range suspiciousPatternDefs {
|
||||
if strings.Contains(lower, def.pattern) {
|
||||
if bytesContainsCI(data, def.pattern) {
|
||||
return def.name
|
||||
}
|
||||
}
|
||||
|
||||
return ""
|
||||
}
|
||||
|
||||
// bytesContainsCI performs case-insensitive byte slice search without allocations
|
||||
func bytesContainsCI(haystack, needle []byte) bool {
|
||||
if len(needle) == 0 {
|
||||
return true
|
||||
}
|
||||
if len(haystack) < len(needle) {
|
||||
return false
|
||||
}
|
||||
|
||||
// Search for needle in haystack (case-insensitive)
|
||||
for i := 0; i <= len(haystack)-len(needle); i++ {
|
||||
if bytesEqualCI(haystack[i:i+len(needle)], needle) {
|
||||
return true
|
||||
}
|
||||
}
|
||||
return false
|
||||
}
|
||||
|
||||
// bytesEqualCI compares two byte slices case-insensitively without allocations
|
||||
func bytesEqualCI(a, b []byte) bool {
|
||||
if len(a) != len(b) {
|
||||
return false
|
||||
}
|
||||
for i := 0; i < len(a); i++ {
|
||||
if unicode.ToLower(rune(a[i])) != unicode.ToLower(rune(b[i])) {
|
||||
return false
|
||||
}
|
||||
}
|
||||
return true
|
||||
}
|
||||
|
||||
// isSuspiciousSIP checks for common attack patterns in SIP traffic (legacy wrapper)
|
||||
func isSuspiciousSIP(data []byte) bool {
|
||||
return detectSuspiciousPattern(data) != ""
|
||||
}
|
||||
|
||||
func min(a, b int) int {
|
||||
if a < b {
|
||||
return a
|
||||
}
|
||||
return b
|
||||
}
|
||||
|
||||
// UnmarshalCaddyfile implements caddyfile.Unmarshaler for SIPMatcher.
|
||||
// Usage in Caddyfile:
|
||||
|
||||
@ -5,6 +5,7 @@ package sipguardian
|
||||
import (
|
||||
"fmt"
|
||||
"net"
|
||||
"sort"
|
||||
"sync"
|
||||
"time"
|
||||
|
||||
@ -631,22 +632,15 @@ func (g *SIPGuardian) evictOldestTrackers(count int) {
|
||||
entries = append(entries, ipTime{ip: ip, time: tracker.firstSeen})
|
||||
}
|
||||
|
||||
// Sort by time (oldest first)
|
||||
for i := 0; i < len(entries)-1; i++ {
|
||||
for j := i + 1; j < len(entries); j++ {
|
||||
if entries[j].time.Before(entries[i].time) {
|
||||
entries[i], entries[j] = entries[j], entries[i]
|
||||
}
|
||||
}
|
||||
}
|
||||
// Sort by time (oldest first) - O(n log n)
|
||||
sort.Slice(entries, func(i, j int) bool {
|
||||
return entries[i].time.Before(entries[j].time)
|
||||
})
|
||||
|
||||
// Evict oldest entries
|
||||
evicted := 0
|
||||
for _, entry := range entries {
|
||||
if evicted >= count {
|
||||
break
|
||||
}
|
||||
delete(g.failureCounts, entry.ip)
|
||||
for i := 0; i < count && i < len(entries); i++ {
|
||||
delete(g.failureCounts, entries[i].ip)
|
||||
evicted++
|
||||
}
|
||||
|
||||
@ -685,21 +679,14 @@ func (g *SIPGuardian) evictOldestBans(count int) {
|
||||
entries = append(entries, ipTime{ip: ip, time: ban.ExpiresAt})
|
||||
}
|
||||
|
||||
// Sort by expiry time (soonest first)
|
||||
for i := 0; i < len(entries)-1; i++ {
|
||||
for j := i + 1; j < len(entries); j++ {
|
||||
if entries[j].time.Before(entries[i].time) {
|
||||
entries[i], entries[j] = entries[j], entries[i]
|
||||
}
|
||||
}
|
||||
}
|
||||
// Sort by expiry time (soonest first) - O(n log n)
|
||||
sort.Slice(entries, func(i, j int) bool {
|
||||
return entries[i].time.Before(entries[j].time)
|
||||
})
|
||||
|
||||
evicted := 0
|
||||
for _, entry := range entries {
|
||||
if evicted >= count {
|
||||
break
|
||||
}
|
||||
delete(g.bannedIPs, entry.ip)
|
||||
for i := 0; i < count && i < len(entries); i++ {
|
||||
delete(g.bannedIPs, entries[i].ip)
|
||||
evicted++
|
||||
}
|
||||
|
||||
|
||||
Loading…
x
Reference in New Issue
Block a user