fix: reject disabled users on all backends in Bind (#470)

A user with disabled = true could still bind on the config backend, since
configHandler.FindUser and LDAPOpsHelper.Bind never checked Disabled while the
SQL backends drop such users at lookup. Enforce it in Bind so every backend
behaves the same.

v2/pkg/handler/disabled_bind_test.go

@@ -0,0 +1,56 @@
+package handler
+
+import (
+	"context"
+	"encoding/hex"
+	"net"
+	"testing"
+
+	"github.com/rs/zerolog"
+	"go.opentelemetry.io/otel/trace/noop"
+	"golang.org/x/crypto/bcrypt"
+
+	"github.com/glauth/glauth/v2/pkg/config"
+	"github.com/glauth/ldap"
+)
+
+func TestConfigBackendDisabledUserCannotBind(t *testing.T) {
+	pw := "correct horse"
+	raw, _ := bcrypt.GenerateFromPassword([]byte(pw), bcrypt.MinCost)
+	hexHash := hex.EncodeToString(raw)
+
+	cfg := &config.Config{}
+	cfg.Users = []config.User{
+		{Name: "activeuser", PrimaryGroup: 5501, PassBcrypt: hexHash, Disabled: false},
+		{Name: "disableduser", PrimaryGroup: 5501, PassBcrypt: hexHash, Disabled: true},
+	}
+
+	logger := zerolog.Nop()
+	tracer := noop.NewTracerProvider().Tracer("f001")
+	helper := NewLDAPOpsHelper(tracer)
+	h := configHandler{
+		backend: config.Backend{
+			BaseDN:             "dc=example,dc=com",
+			NameFormatAsArray:  []string{"cn"},
+			GroupFormatAsArray: []string{"ou"},
+		},
+		log:       &logger,
+		cfg:       cfg,
+		ldohelper: helper,
+		tracer:    tracer,
+	}
+	_, server := net.Pipe()
+	defer server.Close()
+
+	bind := func(dn, pass string) ldap.LDAPResultCode {
+		code, _ := helper.Bind(context.Background(), h, dn, pass, server)
+		return code
+	}
+
+	if code := bind("cn=activeuser,dc=example,dc=com", pw); code != ldap.LDAPResultSuccess {
+		t.Fatalf("active user with correct pw should bind, got %d", code)
+	}
+	if code := bind("cn=disableduser,dc=example,dc=com", pw); code != ldap.LDAPResultInvalidCredentials {
+		t.Errorf("disabled user must be rejected; got code %d, want InvalidCredentials(49)", code)
+	}
+}

v2/pkg/handler/ldapopshelper.go

@@ -102,6 +102,12 @@ func (l LDAPOpsHelper) Bind(ctx context.Context, h LDAPOpsHandler, bindDN, bindS
 		return ldapcode, nil
 	}
 
+	// a disabled account must never authenticate, on any backend
+	if user.Disabled {
+		h.GetLog().Info().Str("binddn", bindDN).Str("src", conn.RemoteAddr().String()).Msg("Bind attempt on disabled account")
+		return ldap.LDAPResultInvalidCredentials, nil
+	}
+
 	validotp := false
 
 	if len(user.Yubikey) == 0 && len(user.OTPSecret) == 0 {