fix(clients): probe inbound settings with a short literal pattern

Deleting a client by an email no record holds fell back to a settings
LIKE '%email%' over every inbound with the raw route parameter, which
costs SQLite the settings length times the pattern length while it holds
the database; a long near-miss email froze the panel for minutes, and
wildcards were not escaped. The pre-filter now uses the first 64 bytes
of the email, escaped; the exact client match after it still decides.

internal/web/service/client_delete_tombstone_test.go

@@ -3,7 +3,9 @@ package service
 import (
 	"errors"
 	"fmt"
+	"strings"
 	"testing"
+	"time"
 
 	"gorm.io/gorm"
 
@@ -197,3 +199,29 @@ func TestRolledBackCreateKeepsTombstone(t *testing.T) {
 		t.Fatal("a create that rolled back withdrew the delete tombstone, so a stale node snapshot can resurrect the deleted client")
 	}
 }
+
+// The email reaches a LIKE pre-filter: a long near-miss costs SQLite text times pattern
+// length while holding the database, and wildcards must not match either.
+func TestFindInboundIdsByClientEmailTreatsTheEmailLiterally(t *testing.T) {
+	setupConflictDB(t)
+	settings := `{"clients":[{"email":"real@x"}],"pad":"` + strings.Repeat("a", 1<<20) + `"}`
+	if err := database.GetDB().Create(&model.Inbound{UserId: 1, Tag: "big", Port: 41601, Protocol: model.VLESS, Settings: settings}).Error; err != nil {
+		t.Fatalf("seed inbound: %v", err)
+	}
+	done := make(chan []int, 1)
+	go func() {
+		ids, _ := (&ClientService{}).findInboundIdsByClientEmail(strings.Repeat("a", 10000) + "b")
+		done <- ids
+	}()
+	select {
+	case ids := <-done:
+		if len(ids) != 0 {
+			t.Fatalf("a wildcard email matched inbounds %v", ids)
+		}
+	case <-time.After(5 * time.Second):
+		t.Fatal("the email lookup is still running after 5 s")
+	}
+	if ids, err := (&ClientService{}).findInboundIdsByClientEmail("real@x"); err != nil || len(ids) != 1 {
+		t.Fatalf("lookup of a real email = %v, %v", ids, err)
+	}
+}

internal/web/service/client_lookup.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"errors"
 	"strings"
+	"unicode/utf8"
 
 	"github.com/mhsanaei/3x-ui/v3/internal/database"
 	"github.com/mhsanaei/3x-ui/v3/internal/database/model"
@@ -247,14 +248,26 @@ func (s *ClientService) HasPendingNode(inboundSvc *InboundService, email string)
 	return inboundSvc.AnyNodePending(ids)
 }
 
+const settingsProbeBytes = 64
+
 // findInboundIdsByClientEmail returns every inbound whose settings.clients[]
 // JSON contains an entry with the given email. Driver-portable (no JSON
 // operators) by parsing in Go — fine for the rare fallback path.
 func (s *ClientService) findInboundIdsByClientEmail(email string) ([]int, error) {
+	// A literal, bounded probe: the email comes from a request, and LIKE costs the settings
+	// length times the pattern length; the exact match below decides.
+	probe := email
+	if len(probe) > settingsProbeBytes {
+		cut := settingsProbeBytes
+		for cut > 0 && !utf8.RuneStart(probe[cut]) {
+			cut--
+		}
+		probe = probe[:cut]
+	}
 	var inbounds []model.Inbound
 	if err := database.GetDB().
 		Select("id, settings").
-		Where("settings LIKE ?", "%"+email+"%").
+		Where("settings LIKE ? ESCAPE '\\'", "%"+escapeLikeLiteral(probe)+"%").
 		Find(&inbounds).Error; err != nil {
 		return nil, err
 	}