Prevent invalid subscription responses from overwriting config.yaml

core/src/main/golang/native/config/fetch.go

@@ -1,6 +1,7 @@
 package config
 
 import (
+	"bytes"
 	"context"
 	"encoding/json"
 	"fmt"
@@ -18,6 +19,7 @@ import (
 
 	"github.com/metacubex/mihomo/adapter/provider"
 	clashHttp "github.com/metacubex/mihomo/component/http"
+	mihomoConfig "github.com/metacubex/mihomo/config"
 	RB "github.com/metacubex/mihomo/rules/bundle"
 )
 
@@ -44,6 +46,11 @@ func openUrl(ctx context.Context, url string) (io.ReadCloser, fetchHeader, error
 	if err != nil {
 		return nil, fetchHeader{}, err
 	}
+	if response.StatusCode < http.StatusOK || response.StatusCode >= http.StatusMultipleChoices {
+		_ = response.Body.Close()
+
+		return nil, fetchHeader{}, fmt.Errorf("subscription request failed: %s", response.Status)
+	}
 
 	return response.Body, fetchHeader{
 		SubscriptionUserInfo:  response.Header.Get("subscription-userinfo"),
@@ -56,6 +63,20 @@ func openContent(url string) (io.ReadCloser, error) {
 }
 
 func fetch(url *U.URL, file string) (fetchHeader, error) {
+	return fetchWithValidator(url, file, nil)
+}
+
+func fetchConfiguration(url *U.URL, file string) (fetchHeader, error) {
+	return fetchWithValidator(url, file, func(data []byte) error {
+		if _, err := mihomoConfig.UnmarshalRawConfig(data); err != nil {
+			return fmt.Errorf("invalid configuration response: %w", err)
+		}
+
+		return nil
+	})
+}
+
+func fetchWithValidator(url *U.URL, file string, validate func([]byte) error) (fetchHeader, error) {
 	ctx, cancel := context.WithTimeout(context.Background(), 60*time.Second)
 	defer cancel()
 
@@ -78,6 +99,18 @@ func fetch(url *U.URL, file string) (fetchHeader, error) {
 
 	defer reader.Close()
 
+	if validate != nil {
+		data, err := io.ReadAll(reader)
+		if err != nil {
+			return fetchHeader{}, err
+		}
+		if err := validate(data); err != nil {
+			return fetchHeader{}, err
+		}
+
+		return header, writeFile(file, bytes.NewReader(data))
+	}
+
 	return header, writeFile(file, reader)
 }
 
@@ -171,7 +204,7 @@ func FetchAndValid(
 
 		reportStatus(string(bytes))
 
-		header, err := fetch(url, configPath)
+		header, err := fetchConfiguration(url, configPath)
 		if err != nil {
 			return err
 		}

core/src/main/golang/native/config/fetch_test.go

@@ -0,0 +1,84 @@
+package config
+
+import (
+	"context"
+	"fmt"
+	"net/http"
+	"net/http/httptest"
+	U "net/url"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestOpenURLRejectsHTTPError(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		http.Error(w, "upstream unavailable", http.StatusBadGateway)
+	}))
+	t.Cleanup(server.Close)
+
+	body, _, err := openUrl(context.Background(), server.URL)
+	if body != nil {
+		_ = body.Close()
+		t.Fatal("expected no response body for an HTTP error")
+	}
+	if err == nil || !strings.Contains(err.Error(), "502 Bad Gateway") {
+		t.Fatalf("expected HTTP status error, got %v", err)
+	}
+}
+
+func TestFetchConfigurationRejectsInvalidResponseWithoutOverwriting(t *testing.T) {
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		_, _ = fmt.Fprint(w, "检测到不受支持的客户端")
+	}))
+	t.Cleanup(server.Close)
+
+	profileDir := t.TempDir()
+	configPath := filepath.Join(profileDir, "config.yaml")
+	original := []byte("proxies: []\nrules: []\n")
+	if err := os.WriteFile(configPath, original, 0600); err != nil {
+		t.Fatalf("write existing configuration: %v", err)
+	}
+
+	url, err := U.Parse(server.URL)
+	if err != nil {
+		t.Fatalf("parse server URL: %v", err)
+	}
+	if _, err := fetchConfiguration(url, configPath); err == nil || !strings.Contains(err.Error(), "invalid configuration response") {
+		t.Fatalf("expected invalid configuration error, got %v", err)
+	}
+
+	current, err := os.ReadFile(configPath)
+	if err != nil {
+		t.Fatalf("read existing configuration: %v", err)
+	}
+	if string(current) != string(original) {
+		t.Fatal("invalid response overwrote the existing configuration")
+	}
+}
+
+func TestFetchConfigurationWritesValidResponse(t *testing.T) {
+	configuration := []byte("proxies: []\nrules: []\n")
+	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
+		_, _ = w.Write(configuration)
+	}))
+	t.Cleanup(server.Close)
+
+	url, err := U.Parse(server.URL)
+	if err != nil {
+		t.Fatalf("parse server URL: %v", err)
+	}
+	configPath := filepath.Join(t.TempDir(), "config.yaml")
+	if _, err := fetchConfiguration(url, configPath); err != nil {
+		t.Fatalf("fetch valid configuration: %v", err)
+	}
+
+	written, err := os.ReadFile(configPath)
+	if err != nil {
+		t.Fatalf("read fetched configuration: %v", err)
+	}
+	if string(written) != string(configuration) {
+		t.Fatal("fetched configuration does not match the response")
+	}
+}