feat(security): add trusted proxies and abuse event cleanup

- Add `WARPBOX_TRUSTED_PROXIES` configuration to restrict accepted forwarded client IP headers to specific proxy IPs/CIDRs, securing client IP resolution.
- Integrate `BanService` into the background cleanup job to automatically purge expired abuse and ban evidence events.
- Update documentation with reverse proxy security guidelines and a production systemd deployment guide.

backend/libs/services/bans.go

@@ -0,0 +1,545 @@
+package services
+
+import (
+	"encoding/json"
+	"errors"
+	"fmt"
+	"net"
+	"sort"
+	"strings"
+	"time"
+
+	"go.etcd.io/bbolt"
+)
+
+var (
+	bansBucket          = []byte("bans")
+	abuseEventsBucket   = []byte("abuse_events")
+	banRulesBucket      = []byte("ban_rules")
+	banSettingsBucket   = []byte("ban_settings")
+	banSettingsKey      = []byte("settings")
+	defaultBanRulesSeed = []byte("default_rules_seeded")
+)
+
+const (
+	BanSourceManual = "manual"
+	BanSourceAuto   = "auto"
+
+	AbuseKindMaliciousPath = "malicious_path"
+	AbuseKindAdminLogin    = "admin_login_failure"
+	AbuseKindUserLogin     = "user_login_failure"
+)
+
+var defaultMaliciousPathRules = []string{
+	"/wp-admin",
+	"/.env",
+	"/.git/config",
+	"/phpmyadmin",
+	"/wp-login.php",
+	"/xmlrpc.php",
+	"/config.php",
+	"/vendor/phpunit",
+	".env",
+	"backup",
+	"dump.sql",
+}
+
+var ErrBanNotFound = errors.New("ban not found")
+
+type BanService struct {
+	db *bbolt.DB
+}
+
+type BanSettings struct {
+	AutoBanEnabled             bool `json:"autoBanEnabled"`
+	AutoBanDurationHours       int  `json:"autoBanDurationHours"`
+	MaliciousPathThreshold     int  `json:"maliciousPathThreshold"`
+	AdminLoginFailureThreshold int  `json:"adminLoginFailureThreshold"`
+	UserLoginFailureThreshold  int  `json:"userLoginFailureThreshold"`
+	AbuseWindowHours           int  `json:"abuseWindowHours"`
+}
+
+type BanRecord struct {
+	ID            string     `json:"id"`
+	Target        string     `json:"target"`
+	Normalized    string     `json:"normalized"`
+	Reason        string     `json:"reason"`
+	Source        string     `json:"source"`
+	CreatedBy     string     `json:"createdBy,omitempty"`
+	CreatedAt     time.Time  `json:"createdAt"`
+	UpdatedAt     time.Time  `json:"updatedAt"`
+	ExpiresAt     time.Time  `json:"expiresAt"`
+	UnbannedAt    *time.Time `json:"unbannedAt,omitempty"`
+	LastMatchedAt *time.Time `json:"lastMatchedAt,omitempty"`
+}
+
+type BanRule struct {
+	ID        string    `json:"id"`
+	Pattern   string    `json:"pattern"`
+	Enabled   bool      `json:"enabled"`
+	CreatedAt time.Time `json:"createdAt"`
+	UpdatedAt time.Time `json:"updatedAt"`
+}
+
+type AbuseEvent struct {
+	Key       string    `json:"key"`
+	IP        string    `json:"ip"`
+	Kind      string    `json:"kind"`
+	Count     int       `json:"count"`
+	FirstSeen time.Time `json:"firstSeen"`
+	LastSeen  time.Time `json:"lastSeen"`
+	Detail    string    `json:"detail,omitempty"`
+}
+
+type MatchedBan struct {
+	Ban BanRecord
+	IP  string
+}
+
+type AbuseResult struct {
+	Event     AbuseEvent
+	Ban       BanRecord
+	Triggered bool
+	Enabled   bool
+}
+
+func NewBanService(db *bbolt.DB) (*BanService, error) {
+	service := &BanService{db: db}
+	err := db.Update(func(tx *bbolt.Tx) error {
+		for _, bucket := range [][]byte{bansBucket, abuseEventsBucket, banRulesBucket, banSettingsBucket} {
+			if _, err := tx.CreateBucketIfNotExists(bucket); err != nil {
+				return err
+			}
+		}
+		if tx.Bucket(banSettingsBucket).Get(banSettingsKey) == nil {
+			data, err := json.Marshal(DefaultBanSettings())
+			if err != nil {
+				return err
+			}
+			if err := tx.Bucket(banSettingsBucket).Put(banSettingsKey, data); err != nil {
+				return err
+			}
+		}
+		rules := tx.Bucket(banRulesBucket)
+		if rules.Get(defaultBanRulesSeed) == nil {
+			now := time.Now().UTC()
+			for _, pattern := range defaultMaliciousPathRules {
+				rule := BanRule{ID: randomID(10), Pattern: pattern, Enabled: true, CreatedAt: now, UpdatedAt: now}
+				data, err := json.Marshal(rule)
+				if err != nil {
+					return err
+				}
+				if err := rules.Put([]byte(rule.ID), data); err != nil {
+					return err
+				}
+			}
+			if err := rules.Put(defaultBanRulesSeed, []byte("1")); err != nil {
+				return err
+			}
+		}
+		return nil
+	})
+	return service, err
+}
+
+func DefaultBanSettings() BanSettings {
+	return BanSettings{
+		AutoBanEnabled:             false,
+		AutoBanDurationHours:       24,
+		MaliciousPathThreshold:     3,
+		AdminLoginFailureThreshold: 10,
+		UserLoginFailureThreshold:  30,
+		AbuseWindowHours:           24,
+	}
+}
+
+func (s *BanService) Settings() (BanSettings, error) {
+	settings := DefaultBanSettings()
+	err := s.db.View(func(tx *bbolt.Tx) error {
+		data := tx.Bucket(banSettingsBucket).Get(banSettingsKey)
+		if data == nil {
+			return nil
+		}
+		if err := json.Unmarshal(data, &settings); err != nil {
+			return err
+		}
+		settings = withBanSettingDefaults(settings)
+		return nil
+	})
+	if err != nil {
+		return BanSettings{}, err
+	}
+	return settings, nil
+}
+
+func (s *BanService) UpdateSettings(settings BanSettings) error {
+	settings = withBanSettingDefaults(settings)
+	if settings.AutoBanDurationHours <= 0 || settings.MaliciousPathThreshold <= 0 ||
+		settings.AdminLoginFailureThreshold <= 0 || settings.UserLoginFailureThreshold <= 0 ||
+		settings.AbuseWindowHours <= 0 {
+		return fmt.Errorf("ban settings must be positive")
+	}
+	data, err := json.Marshal(settings)
+	if err != nil {
+		return err
+	}
+	return s.db.Update(func(tx *bbolt.Tx) error {
+		return tx.Bucket(banSettingsBucket).Put(banSettingsKey, data)
+	})
+}
+
+func withBanSettingDefaults(settings BanSettings) BanSettings {
+	defaults := DefaultBanSettings()
+	if settings.AutoBanDurationHours <= 0 {
+		settings.AutoBanDurationHours = defaults.AutoBanDurationHours
+	}
+	if settings.MaliciousPathThreshold <= 0 {
+		settings.MaliciousPathThreshold = defaults.MaliciousPathThreshold
+	}
+	if settings.AdminLoginFailureThreshold <= 0 {
+		settings.AdminLoginFailureThreshold = defaults.AdminLoginFailureThreshold
+	}
+	if settings.UserLoginFailureThreshold <= 0 {
+		settings.UserLoginFailureThreshold = defaults.UserLoginFailureThreshold
+	}
+	if settings.AbuseWindowHours <= 0 {
+		settings.AbuseWindowHours = defaults.AbuseWindowHours
+	}
+	return settings
+}
+
+func (s *BanService) CreateManualBan(target, reason, createdBy string, expiresAt time.Time) (BanRecord, error) {
+	return s.createBan(target, reason, BanSourceManual, createdBy, expiresAt, time.Now().UTC())
+}
+
+func (s *BanService) createBan(target, reason, source, createdBy string, expiresAt, now time.Time) (BanRecord, error) {
+	normalized, err := NormalizeBanTarget(target)
+	if err != nil {
+		return BanRecord{}, err
+	}
+	reason = strings.TrimSpace(reason)
+	if reason == "" {
+		return BanRecord{}, fmt.Errorf("ban reason is required")
+	}
+	if !expiresAt.After(now) {
+		return BanRecord{}, fmt.Errorf("ban expiration must be in the future")
+	}
+	record := BanRecord{
+		ID:         randomID(12),
+		Target:     strings.TrimSpace(target),
+		Normalized: normalized,
+		Reason:     reason,
+		Source:     source,
+		CreatedBy:  createdBy,
+		CreatedAt:  now,
+		UpdatedAt:  now,
+		ExpiresAt:  expiresAt.UTC(),
+	}
+	data, err := json.Marshal(record)
+	if err != nil {
+		return BanRecord{}, err
+	}
+	err = s.db.Update(func(tx *bbolt.Tx) error {
+		return tx.Bucket(bansBucket).Put([]byte(record.ID), data)
+	})
+	return record, err
+}
+
+func NormalizeBanTarget(target string) (string, error) {
+	target = strings.TrimSpace(target)
+	if target == "" {
+		return "", fmt.Errorf("ban target is required")
+	}
+	if strings.Contains(target, "/") {
+		_, network, err := net.ParseCIDR(target)
+		if err != nil {
+			return "", fmt.Errorf("invalid CIDR target")
+		}
+		return network.String(), nil
+	}
+	ip := net.ParseIP(target)
+	if ip == nil {
+		return "", fmt.Errorf("invalid IP target")
+	}
+	return ip.String(), nil
+}
+
+func (s *BanService) ListBans() ([]BanRecord, error) {
+	records := []BanRecord{}
+	err := s.db.View(func(tx *bbolt.Tx) error {
+		return tx.Bucket(bansBucket).ForEach(func(_, value []byte) error {
+			var record BanRecord
+			if err := json.Unmarshal(value, &record); err != nil {
+				return err
+			}
+			records = append(records, record)
+			return nil
+		})
+	})
+	sort.Slice(records, func(i, j int) bool {
+		return records[i].CreatedAt.After(records[j].CreatedAt)
+	})
+	return records, err
+}
+
+func (s *BanService) Unban(id string, now time.Time) error {
+	id = strings.TrimSpace(id)
+	return s.db.Update(func(tx *bbolt.Tx) error {
+		bucket := tx.Bucket(bansBucket)
+		data := bucket.Get([]byte(id))
+		if data == nil {
+			return ErrBanNotFound
+		}
+		var record BanRecord
+		if err := json.Unmarshal(data, &record); err != nil {
+			return err
+		}
+		now = now.UTC()
+		record.UnbannedAt = &now
+		record.UpdatedAt = now
+		next, err := json.Marshal(record)
+		if err != nil {
+			return err
+		}
+		return bucket.Put([]byte(id), next)
+	})
+}
+
+func (s *BanService) Match(ip string, now time.Time) (MatchedBan, bool, error) {
+	parsed := net.ParseIP(strings.TrimSpace(ip))
+	if parsed == nil {
+		return MatchedBan{}, false, nil
+	}
+	now = now.UTC()
+	var matched BanRecord
+	err := s.db.Update(func(tx *bbolt.Tx) error {
+		bucket := tx.Bucket(bansBucket)
+		return bucket.ForEach(func(key, value []byte) error {
+			if matched.ID != "" {
+				return nil
+			}
+			var record BanRecord
+			if err := json.Unmarshal(value, &record); err != nil {
+				return err
+			}
+			if !record.Active(now) || !banTargetMatches(record.Normalized, parsed) {
+				return nil
+			}
+			record.LastMatchedAt = &now
+			record.UpdatedAt = now
+			next, err := json.Marshal(record)
+			if err != nil {
+				return err
+			}
+			if err := bucket.Put(key, next); err != nil {
+				return err
+			}
+			matched = record
+			return nil
+		})
+	})
+	return MatchedBan{Ban: matched, IP: ip}, matched.ID != "", err
+}
+
+func (r BanRecord) Active(now time.Time) bool {
+	return r.UnbannedAt == nil && r.ExpiresAt.After(now.UTC())
+}
+
+func (r BanRecord) Status(now time.Time) string {
+	switch {
+	case r.UnbannedAt != nil:
+		return "unbanned"
+	case !r.ExpiresAt.After(now.UTC()):
+		return "expired"
+	default:
+		return "active"
+	}
+}
+
+func banTargetMatches(target string, ip net.IP) bool {
+	if strings.Contains(target, "/") {
+		if _, network, err := net.ParseCIDR(target); err == nil {
+			return network.Contains(ip)
+		}
+		return false
+	}
+	targetIP := net.ParseIP(target)
+	return targetIP != nil && targetIP.Equal(ip)
+}
+
+func (s *BanService) ListRules() ([]BanRule, error) {
+	rules := []BanRule{}
+	err := s.db.View(func(tx *bbolt.Tx) error {
+		return tx.Bucket(banRulesBucket).ForEach(func(key, value []byte) error {
+			if string(key) == string(defaultBanRulesSeed) {
+				return nil
+			}
+			var rule BanRule
+			if err := json.Unmarshal(value, &rule); err != nil {
+				return err
+			}
+			rules = append(rules, rule)
+			return nil
+		})
+	})
+	sort.Slice(rules, func(i, j int) bool {
+		return strings.ToLower(rules[i].Pattern) < strings.ToLower(rules[j].Pattern)
+	})
+	return rules, err
+}
+
+func (s *BanService) SaveRules(patterns []string, now time.Time) error {
+	now = now.UTC()
+	return s.db.Update(func(tx *bbolt.Tx) error {
+		bucket := tx.Bucket(banRulesBucket)
+		deleteKeys := [][]byte{}
+		if err := bucket.ForEach(func(key, _ []byte) error {
+			if string(key) == string(defaultBanRulesSeed) {
+				return nil
+			}
+			deleteKeys = append(deleteKeys, append([]byte(nil), key...))
+			return nil
+		}); err != nil {
+			return err
+		}
+		for _, key := range deleteKeys {
+			if err := bucket.Delete(key); err != nil {
+				return err
+			}
+		}
+		seen := map[string]bool{}
+		for _, pattern := range patterns {
+			pattern = strings.TrimSpace(pattern)
+			if pattern == "" || seen[strings.ToLower(pattern)] {
+				continue
+			}
+			seen[strings.ToLower(pattern)] = true
+			rule := BanRule{ID: randomID(10), Pattern: pattern, Enabled: true, CreatedAt: now, UpdatedAt: now}
+			data, err := json.Marshal(rule)
+			if err != nil {
+				return err
+			}
+			if err := bucket.Put([]byte(rule.ID), data); err != nil {
+				return err
+			}
+		}
+		return nil
+	})
+}
+
+func (s *BanService) DeleteRule(id string) error {
+	return s.db.Update(func(tx *bbolt.Tx) error {
+		return tx.Bucket(banRulesBucket).Delete([]byte(strings.TrimSpace(id)))
+	})
+}
+
+func (s *BanService) MaliciousPattern(path string) (string, error) {
+	if shouldSkipMaliciousPath(path) {
+		return "", nil
+	}
+	rules, err := s.ListRules()
+	if err != nil {
+		return "", err
+	}
+	lowerPath := strings.ToLower(path)
+	for _, rule := range rules {
+		if rule.Enabled && strings.Contains(lowerPath, strings.ToLower(rule.Pattern)) {
+			return rule.Pattern, nil
+		}
+	}
+	return "", nil
+}
+
+func shouldSkipMaliciousPath(path string) bool {
+	return path == "/health" || path == "/healthz" || path == "/api/v1/health" || strings.HasPrefix(path, "/static/")
+}
+
+func (s *BanService) RecordAbuse(ip, kind, detail string, threshold int, now time.Time) (AbuseResult, error) {
+	settings, err := s.Settings()
+	if err != nil {
+		return AbuseResult{}, err
+	}
+	if !settings.AutoBanEnabled {
+		return AbuseResult{Enabled: false}, nil
+	}
+	if threshold <= 0 {
+		return AbuseResult{Enabled: true}, nil
+	}
+	now = now.UTC()
+	window := time.Duration(settings.AbuseWindowHours) * time.Hour
+	key := abuseKey(ip, kind)
+	var event AbuseEvent
+	var triggered bool
+	var ban BanRecord
+	err = s.db.Update(func(tx *bbolt.Tx) error {
+		bucket := tx.Bucket(abuseEventsBucket)
+		data := bucket.Get([]byte(key))
+		if data != nil {
+			if err := json.Unmarshal(data, &event); err != nil {
+				return err
+			}
+		}
+		if data == nil || now.Sub(event.FirstSeen) > window {
+			event = AbuseEvent{Key: key, IP: ip, Kind: kind, FirstSeen: now}
+		}
+		event.Count++
+		event.LastSeen = now
+		event.Detail = detail
+		next, err := json.Marshal(event)
+		if err != nil {
+			return err
+		}
+		if err := bucket.Put([]byte(key), next); err != nil {
+			return err
+		}
+		triggered = event.Count >= threshold
+		return nil
+	})
+	if err != nil || !triggered {
+		return AbuseResult{Event: event, Triggered: false, Enabled: true}, err
+	}
+	reason := fmt.Sprintf("%s threshold reached: %s", strings.ReplaceAll(kind, "_", " "), detail)
+	ban, err = s.createBan(ip, reason, BanSourceAuto, "", now.Add(time.Duration(settings.AutoBanDurationHours)*time.Hour), now)
+	if err != nil {
+		return AbuseResult{}, err
+	}
+	return AbuseResult{Event: event, Ban: ban, Triggered: true, Enabled: true}, nil
+}
+
+func (s *BanService) CleanupAbuseEvents(now time.Time) (int, error) {
+	settings, err := s.Settings()
+	if err != nil {
+		return 0, err
+	}
+	cutoff := now.UTC().Add(-time.Duration(settings.AbuseWindowHours) * time.Hour)
+	cleaned := 0
+	err = s.db.Update(func(tx *bbolt.Tx) error {
+		bucket := tx.Bucket(abuseEventsBucket)
+		deleteKeys := [][]byte{}
+		if err := bucket.ForEach(func(key, value []byte) error {
+			var event AbuseEvent
+			if err := json.Unmarshal(value, &event); err != nil {
+				deleteKeys = append(deleteKeys, append([]byte(nil), key...))
+				return nil
+			}
+			if event.LastSeen.Before(cutoff) {
+				deleteKeys = append(deleteKeys, append([]byte(nil), key...))
+			}
+			return nil
+		}); err != nil {
+			return err
+		}
+		for _, key := range deleteKeys {
+			if err := bucket.Delete(key); err != nil {
+				return err
+			}
+			cleaned++
+		}
+		return nil
+	})
+	return cleaned, err
+}
+
+func abuseKey(ip, kind string) string {
+	return kind + ":" + strings.TrimSpace(ip)
+}

backend/libs/services/bans_test.go

@@ -0,0 +1,117 @@
+package services
+
+import (
+	"log/slog"
+	"path/filepath"
+	"testing"
+	"time"
+)
+
+func TestBanServiceMatchesIPAndCIDR(t *testing.T) {
+	bans := newTestBanService(t)
+	now := time.Date(2026, 5, 31, 12, 0, 0, 0, time.UTC)
+	ipBan, err := bans.createBan("203.0.113.5", "single IP", BanSourceManual, "test", now.Add(time.Hour), now)
+	if err != nil {
+		t.Fatalf("createBan IP returned error: %v", err)
+	}
+	cidrBan, err := bans.createBan("198.51.100.0/24", "CIDR", BanSourceManual, "test", now.Add(time.Hour), now)
+	if err != nil {
+		t.Fatalf("createBan CIDR returned error: %v", err)
+	}
+
+	if matched, ok, err := bans.Match("203.0.113.5", now); err != nil || !ok || matched.Ban.ID != ipBan.ID {
+		t.Fatalf("Match IP = %+v, %v, %v", matched, ok, err)
+	}
+	if matched, ok, err := bans.Match("198.51.100.42", now); err != nil || !ok || matched.Ban.ID != cidrBan.ID {
+		t.Fatalf("Match CIDR = %+v, %v, %v", matched, ok, err)
+	}
+	if _, ok, err := bans.Match("192.0.2.1", now); err != nil || ok {
+		t.Fatalf("Match unrelated = %v, %v", ok, err)
+	}
+}
+
+func TestBanServiceIgnoresExpiredAndUnbanned(t *testing.T) {
+	bans := newTestBanService(t)
+	now := time.Date(2026, 5, 31, 12, 0, 0, 0, time.UTC)
+	expired, err := bans.createBan("203.0.113.6", "expired", BanSourceManual, "test", now.Add(time.Hour), now)
+	if err != nil {
+		t.Fatalf("createBan expired returned error: %v", err)
+	}
+	if _, ok, err := bans.Match("203.0.113.6", now.Add(2*time.Hour)); err != nil || ok {
+		t.Fatalf("expired Match = %v, %v", ok, err)
+	}
+	active, err := bans.createBan("203.0.113.7", "active", BanSourceManual, "test", now.Add(time.Hour), now)
+	if err != nil {
+		t.Fatalf("createBan active returned error: %v", err)
+	}
+	if err := bans.Unban(active.ID, now.Add(time.Minute)); err != nil {
+		t.Fatalf("Unban returned error: %v", err)
+	}
+	if _, ok, err := bans.Match("203.0.113.7", now.Add(2*time.Minute)); err != nil || ok {
+		t.Fatalf("unbanned Match = %v, %v", ok, err)
+	}
+	if expired.Status(now.Add(2*time.Hour)) != "expired" {
+		t.Fatalf("expired status = %q", expired.Status(now.Add(2*time.Hour)))
+	}
+}
+
+func TestBanServiceAutoBanThresholdsAndDisabled(t *testing.T) {
+	bans := newTestBanService(t)
+	now := time.Date(2026, 5, 31, 12, 0, 0, 0, time.UTC)
+	if result, err := bans.RecordAbuse("203.0.113.8", AbuseKindMaliciousPath, "/.env", 3, now); err != nil || result.Enabled {
+		t.Fatalf("disabled RecordAbuse = %+v, %v", result, err)
+	}
+	settings, err := bans.Settings()
+	if err != nil {
+		t.Fatalf("Settings returned error: %v", err)
+	}
+	settings.AutoBanEnabled = true
+	if err := bans.UpdateSettings(settings); err != nil {
+		t.Fatalf("UpdateSettings returned error: %v", err)
+	}
+	for i := 0; i < 2; i++ {
+		result, err := bans.RecordAbuse("203.0.113.8", AbuseKindMaliciousPath, "/.env", 3, now.Add(time.Duration(i)*time.Minute))
+		if err != nil || result.Triggered {
+			t.Fatalf("RecordAbuse before threshold = %+v, %v", result, err)
+		}
+	}
+	result, err := bans.RecordAbuse("203.0.113.8", AbuseKindMaliciousPath, "/.env", 3, now.Add(3*time.Minute))
+	if err != nil || !result.Triggered || result.Ban.ID == "" {
+		t.Fatalf("RecordAbuse threshold = %+v, %v", result, err)
+	}
+}
+
+func TestBanServiceMaliciousPathRules(t *testing.T) {
+	bans := newTestBanService(t)
+	if pattern, err := bans.MaliciousPattern("/foo/.ENV"); err != nil || pattern == "" {
+		t.Fatalf("MaliciousPattern .env = %q, %v", pattern, err)
+	}
+	if pattern, err := bans.MaliciousPattern("/static/.env"); err != nil || pattern != "" {
+		t.Fatalf("MaliciousPattern static = %q, %v", pattern, err)
+	}
+	if err := bans.SaveRules([]string{"/custom-probe"}, time.Now().UTC()); err != nil {
+		t.Fatalf("SaveRules returned error: %v", err)
+	}
+	if pattern, err := bans.MaliciousPattern("/x/CUSTOM-probe"); err != nil || pattern != "/custom-probe" {
+		t.Fatalf("MaliciousPattern custom = %q, %v", pattern, err)
+	}
+}
+
+func newTestBanService(t *testing.T) *BanService {
+	t.Helper()
+	root := t.TempDir()
+	upload, err := NewUploadService(1024*1024, filepath.Join(root, "data"), "http://example.test", slog.Default())
+	if err != nil {
+		t.Fatalf("NewUploadService returned error: %v", err)
+	}
+	t.Cleanup(func() {
+		if err := upload.Close(); err != nil {
+			t.Fatalf("Close returned error: %v", err)
+		}
+	})
+	bans, err := NewBanService(upload.DB())
+	if err != nil {
+		t.Fatalf("NewBanService returned error: %v", err)
+	}
+	return bans
+}

backend/libs/services/proxy.go

@@ -0,0 +1,75 @@
+package services
+
+import (
+	"context"
+	"net"
+	"net/http"
+	"strings"
+)
+
+type clientIPContextKey struct{}
+
+func WithClientIP(r *http.Request, ip string) *http.Request {
+	return r.WithContext(context.WithValue(r.Context(), clientIPContextKey{}, ip))
+}
+
+func ClientIPFromContext(r *http.Request) (string, bool) {
+	ip, ok := r.Context().Value(clientIPContextKey{}).(string)
+	return ip, ok && ip != ""
+}
+
+// ClientIP resolves the effective client IP. When trustedProxies is empty,
+// forwarded headers are trusted for easy reverse-proxy/container defaults.
+func ClientIP(remoteAddr, forwardedFor, realIP string, trustedProxies []string) string {
+	remoteIP := remoteIPOnly(remoteAddr)
+	if len(trustedProxies) == 0 || remoteTrusted(remoteIP, trustedProxies) {
+		if ip := firstForwardedIP(forwardedFor); ip != "" {
+			return ip
+		}
+		if ip := strings.TrimSpace(realIP); ip != "" {
+			return ip
+		}
+	}
+	return remoteIP
+}
+
+func remoteIPOnly(remoteAddr string) string {
+	host := strings.TrimSpace(remoteAddr)
+	if splitHost, _, err := net.SplitHostPort(remoteAddr); err == nil {
+		host = splitHost
+	}
+	return strings.Trim(host, "[]")
+}
+
+func firstForwardedIP(forwardedFor string) string {
+	for _, part := range strings.Split(forwardedFor, ",") {
+		ip := strings.TrimSpace(part)
+		if ip != "" {
+			return strings.Trim(ip, "[]")
+		}
+	}
+	return ""
+}
+
+func remoteTrusted(remoteIP string, trustedProxies []string) bool {
+	parsed := net.ParseIP(remoteIP)
+	if parsed == nil {
+		return false
+	}
+	for _, trusted := range trustedProxies {
+		trusted = strings.TrimSpace(trusted)
+		if trusted == "" {
+			continue
+		}
+		if strings.Contains(trusted, "/") {
+			if _, network, err := net.ParseCIDR(trusted); err == nil && network.Contains(parsed) {
+				return true
+			}
+			continue
+		}
+		if ip := net.ParseIP(trusted); ip != nil && ip.Equal(parsed) {
+			return true
+		}
+	}
+	return false
+}

backend/libs/services/proxy_test.go

@@ -0,0 +1,29 @@
+package services
+
+import "testing"
+
+func TestClientIPTrustsForwardedHeadersByDefault(t *testing.T) {
+	ip := ClientIP("127.0.0.1:6070", "203.0.113.10, 10.0.0.2", "198.51.100.2", nil)
+	if ip != "203.0.113.10" {
+		t.Fatalf("ClientIP = %q, want forwarded IP", ip)
+	}
+}
+
+func TestClientIPUsesTrustedProxyCIDRs(t *testing.T) {
+	trusted := []string{"127.0.0.1", "172.16.0.0/12"}
+	ip := ClientIP("172.20.0.4:6070", "203.0.113.11", "", trusted)
+	if ip != "203.0.113.11" {
+		t.Fatalf("trusted ClientIP = %q", ip)
+	}
+	spoofed := ClientIP("198.51.100.20:6070", "203.0.113.12", "203.0.113.13", trusted)
+	if spoofed != "198.51.100.20" {
+		t.Fatalf("untrusted ClientIP = %q, want remote addr", spoofed)
+	}
+}
+
+func TestClientIPFallsBackToRealIP(t *testing.T) {
+	ip := ClientIP("127.0.0.1:6070", "", "203.0.113.14", nil)
+	if ip != "203.0.113.14" {
+		t.Fatalf("ClientIP = %q, want real IP", ip)
+	}
+}

backend/libs/services/settings.go

@@ -4,7 +4,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"math"
-	"net"
 	"strconv"
 	"strings"
 	"time"
@@ -484,19 +483,3 @@ func normalizeBackendID(id string) string {
 	}
 	return id
 }
-
-func ClientIP(remoteAddr, forwardedFor string) string {
-	if forwardedFor != "" {
-		parts := strings.Split(forwardedFor, ",")
-		if ip := strings.TrimSpace(parts[0]); ip != "" {
-			return ip
-		}
-	}
-	host := remoteAddr
-	if strings.Contains(remoteAddr, ":") {
-		if splitHost, _, err := net.SplitHostPort(remoteAddr); err == nil {
-			host = splitHost
-		}
-	}
-	return host
-}