Checksum games .text section if we don't recognize the timestamp

src/Utility.cpp

@@ -65,3 +65,41 @@ HWND FindMainWindow(DWORD process_id)
   EnumWindows(enum_windows_callback, (LPARAM)&data);
   return data.window_handle;
 }
+
+// https://rosettacode.org/wiki/CRC-32#Implementation_2
+uint32_t
+rc_crc32(uint32_t crc, const char* buf, size_t len)
+{
+  static uint32_t table[256];
+  static int have_table = 0;
+  uint32_t rem;
+  uint8_t octet;
+  int i, j;
+  const char* p, * q;
+
+  /* This check is not thread safe; there is no mutex. */
+  if (have_table == 0) {
+    /* Calculate CRC table. */
+    for (i = 0; i < 256; i++) {
+      rem = i;  /* remainder from polynomial division */
+      for (j = 0; j < 8; j++) {
+        if (rem & 1) {
+          rem >>= 1;
+          rem ^= 0xedb88320;
+        }
+        else
+          rem >>= 1;
+      }
+      table[i] = rem;
+    }
+    have_table = 1;
+  }
+
+  crc = ~crc;
+  q = buf + len;
+  for (p = buf; p < q; p++) {
+    octet = *p;  /* Cast to unsigned octet. */
+    crc = (crc >> 8) ^ table[(crc & 0xff) ^ octet];
+  }
+  return ~crc;
+}

src/dllmain.cpp

@@ -1,11 +1,13 @@
 #include "pch.h"
 
-#define SDK_VERSION "0.1.26"
+#define SDK_VERSION "0.1.26a"
 
 const uint32_t Addr_Timestamp = 0x1E0;
 const uint32_t Value_Timestamp = 1626315361; // 2021/07/15 02:16:01
 const uint32_t Value_Timestamp_patch1 = 1629818287; // 2021/08/24 15:18:07 (no code changes?)
 
+const uint32_t Game_TextSectionChecksum = 0x13ce422f; // patch0 & patch1 share this
+
 const uint32_t Addr_ProcessEvent = 0x14CBA50;
 const uint32_t Addr_GUObjectArray = 0x44DC350;
 const uint32_t Addr_Names = 0x4C6DE10;
@@ -165,6 +167,8 @@ void UAchCharacterBuildComponent__SetCulling_Hook(UAchCharacterBuildComponent* t
   UAchCharacterBuildComponent__SetCulling_Orig(thisptr, Options.CharaDisableCull ? false : bCulling);
 }
 
+// Ran by DllMain, before the games code itself has ran (or any wrappers like SteamStub etc)
+// Not recommended to put anything that writes to game EXE here, since it might be writing over still-encrypted data
 bool InitGame()
 {
   printf("\nArise-SDK " SDK_VERSION " - https://github.com/emoose/Arise-SDK\n");
@@ -178,14 +182,6 @@ bool InitGame()
   }
   mBaseAddress = reinterpret_cast<uintptr_t>(GameHModule);
 
-  // Check that this is the EXE we were built against...
-  uint32_t timestamp = *reinterpret_cast<uint32_t*>(mBaseAddress + Addr_Timestamp);
-  if (timestamp != Value_Timestamp && timestamp != Value_Timestamp_patch1)
-  {
-    MessageBoxA(0, "Unsupported 'Tales of Arise.exe' version, aborting Arise-SDK load...", "Arise-SDK", 0);
-    return false;
-  }
-
   // Get folder path of currently running EXE
   GetModuleFileName(GameHModule, IniPath, 4096);
   int len = wcslen(IniPath);
@@ -551,10 +547,34 @@ void RefreshEngineSettings_Hook()
     RefreshEngineSettings_Orig();
 }
 
-
+// InitPlugin is ran sometime after steamstub decrypted the exe - usually within the first frame or so of the game
+// Some parts of the game might already be inited by this time though, requiring a different method of handling them
 void InitPlugin()
 {
   inited = false;
+
+  // Check that this is the EXE we were built against...
+  uint32_t timestamp = *reinterpret_cast<uint32_t*>(mBaseAddress + Addr_Timestamp);
+  if (timestamp != Value_Timestamp && timestamp != Value_Timestamp_patch1)
+  {
+    // Not a known EXE timestamp, we'll checksum the .text section since some patches are known to just update timestamps...
+    bool isKnown = false;
+    int textSize = 0;
+    void* textSection = ModuleGetSection((void*)mBaseAddress, ".text", &textSize);
+    if (textSection)
+    {
+      auto checksum = rc_crc32(0, (char*)textSection, textSize);
+      isKnown = checksum == Game_TextSectionChecksum;
+    }
+
+    if (!isKnown)
+    {
+      MessageBoxA(0, "Unsupported 'Tales of Arise.exe' version, aborting Arise-SDK load...", "Arise-SDK", 0);
+      return;
+    }
+  }
+
+
   PostProc_Init();
 
   UObject::ProcessEventPtr = reinterpret_cast<ProcessEventFn>(mBaseAddress + Addr_ProcessEvent);

src/pch.h

@@ -47,6 +47,7 @@ extern uintptr_t mBaseAddress;
 void InitPlugin();
 
 // proxy.cpp
+void* ModuleGetSection(void* Module, const char* SectionName, int* OutSectionSize);
 void Proxy_InitSteamStub();
 
 // UE4Hook.cpp
@@ -60,6 +61,7 @@ bool DirExists(const WCHAR* DirPath);
 HWND FindMainWindow(DWORD process_id);
 bool INI_GetBool(const WCHAR* IniPath, const WCHAR* Section, const WCHAR* Key, bool DefaultValue);
 float INI_GetFloat(const WCHAR* IniPath, const WCHAR* Section, const WCHAR* Key, float DefaultValue);
+uint32_t rc_crc32(uint32_t crc, const char* buf, size_t len);
 
 // PostProcOverrides.cpp
 void PostProc_AddCVars(IConsoleManager* ConsoleManager);

src/proxy.cpp

@@ -222,6 +222,39 @@ void* ModuleDirectoryEntryData(void* Module, int DirectoryEntry, int* EntrySize
   return base + entryAddr;
 }
 
+void* ModuleGetSection(void* Module, const char* SectionName, int* OutSectionSize)
+{
+  BYTE* base = reinterpret_cast<BYTE*>(Module);
+  IMAGE_DOS_HEADER* dosHeader = reinterpret_cast<IMAGE_DOS_HEADER*>(base);
+  if (dosHeader->e_magic != IMAGE_DOS_SIGNATURE)
+    return nullptr; // invalid header :(
+
+  IMAGE_NT_HEADERS* ntHeader = reinterpret_cast<IMAGE_NT_HEADERS*>(base + dosHeader->e_lfanew);
+  if (ntHeader->Signature != IMAGE_NT_SIGNATURE)
+    return nullptr;
+
+  IMAGE_SECTION_HEADER* sections = reinterpret_cast<IMAGE_SECTION_HEADER*>(&ntHeader[1]);
+
+  IMAGE_SECTION_HEADER* foundSection = nullptr;
+  for (int i = 0; i < ntHeader->FileHeader.NumberOfSections; i++)
+  {
+    IMAGE_SECTION_HEADER* section = &sections[i];
+    if (!strncmp((const char*)section->Name, SectionName, 8))
+    {
+      foundSection = section;
+      break;
+    }
+  }
+
+  if (!foundSection)
+    return nullptr;
+
+  if (OutSectionSize)
+    *OutSectionSize = foundSection->Misc.VirtualSize;
+
+  return base + foundSection->VirtualAddress;
+}
+
 FARPROC* GetIATPointer(void* Module, const char* LibraryName, const char* ImportName)
 {
   auto* base = (BYTE*)Module;

src/resource.rc

@@ -50,8 +50,8 @@ END
 //
 
 VS_VERSION_INFO VERSIONINFO
- FILEVERSION 0,1,26,0
- PRODUCTVERSION 0,1,26,0
+ FILEVERSION 0,1,26,1
+ PRODUCTVERSION 0,1,26,1
  FILEFLAGSMASK 0x3fL
 #ifdef _DEBUG
  FILEFLAGS 0x1L
@@ -68,12 +68,12 @@ BEGIN
         BEGIN
             VALUE "CompanyName", "emoose"
             VALUE "FileDescription", "Arise-SDK - improvement extension for Tales of Arise"
-            VALUE "FileVersion", "0.1.26.0"
+            VALUE "FileVersion", "0.1.26.1"
             VALUE "InternalName", "Arise-SDK.dll"
             VALUE "LegalCopyright", "emoose - 2021"
             VALUE "OriginalFilename", "Arise-SDK.dll"
             VALUE "ProductName", "Arise-SDK"
-            VALUE "ProductVersion", "0.1.26.0"
+            VALUE "ProductVersion", "0.1.26.1"
         END
     END
     BLOCK "VarFileInfo"