feat(security): 仅加载显式授权的外部 DLL

Runtime/Loading/ShrinkExternalModAssemblyLoader.cs

@@ -34,17 +34,22 @@ namespace ShrinkModFramework
         private static bool _resolveRegistered;
         private static int _lastWarnedResidentCount;
 
-        public static IReadOnlyList<Assembly> LoadExternalAssemblies(ShrinkModFrameworkSettings settings, bool verboseLogging)
+        public static IReadOnlyList<Assembly> LoadExternalAssemblies(
+            ShrinkModFrameworkSettings settings,
+            bool verboseLogging,
+            IEnumerable<string> authorizedDllPaths = null)
         {
-            return ScanExternalAssemblyRevisions(settings, verboseLogging)
+            return ScanExternalAssemblyRevisions(settings, verboseLogging, authorizedDllPaths)
                 .Select(revision => revision.Assembly)
                 .ToArray();
         }
 
         internal static IReadOnlyList<ExternalAssemblyRevision> ScanExternalAssemblyRevisions(
-            ShrinkModFrameworkSettings settings, bool verboseLogging)
+            ShrinkModFrameworkSettings settings,
+            bool verboseLogging,
+            IEnumerable<string> authorizedDllPaths = null)
         {
-            if (settings != null && !settings.enableExternalDllMods)
+            if (settings == null || !settings.enableExternalDllMods)
             {
                 CurrentAssemblyRevisions.Clear();
                 KnownAssemblyFiles.Clear();
@@ -52,27 +57,23 @@ namespace ShrinkModFramework
             }
 
 #if ENABLE_IL2CPP && !UNITY_EDITOR
-            Debug.LogWarning("[ShrinkModFramework] IL2CPP 运行时不支持外部 DLL 热加载，已跳过外部模组扫描。");
+            Debug.LogWarning("[ShrinkModFramework] IL2CPP 运行时不支持外部 DLL 加载，已跳过授权模组。");
             return Array.Empty<ExternalAssemblyRevision>();
 #else
-            var modsDirectory = GetExternalModsDirectory(settings);
-            if (settings == null || settings.autoCreateExternalModsDirectory)
-                Directory.CreateDirectory(modsDirectory);
-
             RegisterAssemblyResolve();
 
-            var dllPaths = Directory.GetFiles(modsDirectory, "*.dll", SearchOption.AllDirectories)
-                .Select(Path.GetFullPath)
-                .OrderBy(path => path, StringComparer.OrdinalIgnoreCase)
-                .ToArray();
-            var presentPaths = new HashSet<string>(dllPaths, StringComparer.OrdinalIgnoreCase);
+            var dllPaths = NormalizeAuthorizedPaths(authorizedDllPaths);
+            var presentPaths = new HashSet<string>(
+                dllPaths.Where(File.Exists),
+                StringComparer.OrdinalIgnoreCase);
 
-            foreach (var dllPath in dllPaths
+            KnownAssemblyFiles.Clear();
+            foreach (var dllPath in presentPaths)
+                KnownAssemblyFiles[Path.GetFileNameWithoutExtension(dllPath)] = dllPath;
+
+            foreach (var dllPath in presentPaths
                          .OrderBy(path => path, StringComparer.OrdinalIgnoreCase))
             {
-                var assemblyName = Path.GetFileNameWithoutExtension(dllPath);
-                KnownAssemblyFiles[assemblyName] = dllPath;
-
                 try
                 {
                     var bytes = File.ReadAllBytes(dllPath);
@@ -131,6 +132,41 @@ namespace ShrinkModFramework
 #endif
         }
 
+        private static string[] NormalizeAuthorizedPaths(IEnumerable<string> authorizedDllPaths)
+        {
+            if (authorizedDllPaths == null)
+                return Array.Empty<string>();
+
+            var normalized = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+            foreach (var rawPath in authorizedDllPaths)
+            {
+                if (string.IsNullOrWhiteSpace(rawPath))
+                    continue;
+
+                string fullPath;
+                try
+                {
+                    fullPath = Path.GetFullPath(rawPath.Trim());
+                }
+                catch (Exception exception)
+                {
+                    throw new ArgumentException($"授权 DLL 路径无效：{rawPath}",
+                        nameof(authorizedDllPaths), exception);
+                }
+
+                if (!string.Equals(Path.GetExtension(fullPath), ".dll",
+                        StringComparison.OrdinalIgnoreCase))
+                {
+                    throw new ArgumentException($"授权路径不是 DLL：{fullPath}",
+                        nameof(authorizedDllPaths));
+                }
+
+                normalized.Add(fullPath);
+            }
+
+            return normalized.OrderBy(path => path, StringComparer.OrdinalIgnoreCase).ToArray();
+        }
+
         internal static bool IsExternalAssembly(Assembly assembly) =>
             assembly != null && ExternalAssemblyHistory.ContainsKey(assembly);
 
@@ -268,13 +304,38 @@ namespace ShrinkModFramework
             if (!KnownAssemblyFiles.TryGetValue(requestedName, out var path) || !File.Exists(path))
                 return null;
 
-            try
+            lock (ResolveLock)
             {
-                return Assembly.Load(File.ReadAllBytes(path));
-            }
-            catch
-            {
-                return null;
+                try
+                {
+                    var bytes = File.ReadAllBytes(path);
+                    var revision = ComputeSha256(bytes);
+                    if (CurrentAssemblyRevisions.TryGetValue(path, out var current) &&
+                        string.Equals(current.Revision, revision, StringComparison.Ordinal))
+                    {
+                        return current.Assembly;
+                    }
+
+                    var pdbPath = Path.ChangeExtension(path, ".pdb");
+                    var pdbBytes = File.Exists(pdbPath) ? File.ReadAllBytes(pdbPath) : null;
+                    var assembly = pdbBytes != null
+                        ? Assembly.Load(bytes, pdbBytes)
+                        : Assembly.Load(bytes);
+                    var loadedRevision = new ExternalAssemblyRevision
+                    {
+                        Path = path,
+                        Revision = revision,
+                        Assembly = assembly,
+                        LoadedBytes = bytes.LongLength + (pdbBytes?.LongLength ?? 0L)
+                    };
+                    CurrentAssemblyRevisions[path] = loadedRevision;
+                    ExternalAssemblyHistory[assembly] = loadedRevision;
+                    return assembly;
+                }
+                catch
+                {
+                    return null;
+                }
             }
         }
     }