fix(server): apply the outbound address policy to remote cert pinning

The remote certificate fetch now dials through the same netsafe guard
as the REALITY target scan. A private or loopback endpoint is refused
unless the request carries allowPrivate; the inbound form asks the
operator to confirm and retries with the opt-in.

internal/web/service/server.go

@@ -39,6 +39,7 @@ import (
 	"github.com/mhsanaei/3x-ui/v3/internal/database/model"
 	"github.com/mhsanaei/3x-ui/v3/internal/logger"
 	"github.com/mhsanaei/3x-ui/v3/internal/util/common"
+	"github.com/mhsanaei/3x-ui/v3/internal/util/netsafe"
 	"github.com/mhsanaei/3x-ui/v3/internal/util/sys"
 	"github.com/mhsanaei/3x-ui/v3/internal/xray"
 
@@ -2757,7 +2758,8 @@ func walkCertFiles(node any, out []string) []string {
 // proxy). A native handshake replaces the old `xray tls ping` subprocess so the
 // real dial/handshake failure (connection refused, timeout, …) surfaces
 // verbatim. `server` may be host or host:port; the port defaults to 443.
-func (s *ServerService) GetRemoteCertHash(server string) ([]string, error) {
+// allowPrivate lifts the SSRF guard for this one probe (the panel's confirmed opt-in).
+func (s *ServerService) GetRemoteCertHash(server string, allowPrivate bool) ([]string, error) {
 	server = strings.TrimSpace(server)
 	if server == "" {
 		return nil, common.NewError("no server provided")
@@ -2768,10 +2770,11 @@ func (s *ServerService) GetRemoteCertHash(server string) ([]string, error) {
 		host, port = h, p
 	}
 
-	dialer := stdnet.Dialer{Timeout: 10 * time.Second}
-	tcpConn, err := dialer.Dial("tcp", stdnet.JoinHostPort(host, port))
+	ctx, cancel := context.WithTimeout(netsafe.ContextWithAllowPrivate(context.Background(), allowPrivate), 10*time.Second)
+	defer cancel()
+	tcpConn, err := netsafe.SSRFGuardedDialContext(ctx, "tcp", stdnet.JoinHostPort(host, port))
 	if err != nil {
-		return nil, common.NewErrorf("failed to dial %s: %s", stdnet.JoinHostPort(host, port), err)
+		return nil, fmt.Errorf("failed to dial %s: %w", stdnet.JoinHostPort(host, port), err)
 	}
 	defer tcpConn.Close()
 	_ = tcpConn.SetDeadline(time.Now().Add(15 * time.Second))

internal/web/service/server_remote_cert_hash_test.go

@@ -0,0 +1,38 @@
+package service
+
+import (
+	"crypto/sha256"
+	"encoding/hex"
+	"errors"
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"github.com/mhsanaei/3x-ui/v3/internal/util/netsafe"
+)
+
+func TestGetRemoteCertHashGuardsPrivateTargets(t *testing.T) {
+	srv := httptest.NewTLSServer(http.HandlerFunc(func(http.ResponseWriter, *http.Request) {}))
+	defer srv.Close()
+	target := strings.TrimPrefix(srv.URL, "https://")
+	sum := sha256.Sum256(srv.Certificate().Raw)
+	want := hex.EncodeToString(sum[:])
+
+	t.Run("loopback refused without opt-in", func(t *testing.T) {
+		hashes, err := (&ServerService{}).GetRemoteCertHash(target, false)
+		if !errors.Is(err, netsafe.ErrPrivateAddressBlocked) {
+			t.Fatalf("GetRemoteCertHash(%s) = %v, %v; want ErrPrivateAddressBlocked", target, hashes, err)
+		}
+	})
+
+	t.Run("loopback read with opt-in", func(t *testing.T) {
+		hashes, err := (&ServerService{}).GetRemoteCertHash(target, true)
+		if err != nil {
+			t.Fatalf("GetRemoteCertHash(%s, allowPrivate): %v", target, err)
+		}
+		if len(hashes) != 1 || hashes[0] != want {
+			t.Fatalf("hashes = %v, want [%s]", hashes, want)
+		}
+	})
+}