1 files changed, 110 insertions, 0 deletions

diff --git a/C/DllSecur.c b/C/DllSecur.c
new file mode 100644
index 0000000..d81508c
--- /dev/null
+++ b/C/DllSecur.c
@@ -0,0 +1,110 @@
+/* DllSecur.c -- DLL loading security
+2021-12-25 : Igor Pavlov : Public domain */
+
+#include "Precomp.h"
+
+#ifdef _WIN32
+
+#include <Windows.h>
+
+#include "DllSecur.h"
+
+#ifndef UNDER_CE
+
+typedef BOOL (WINAPI *Func_SetDefaultDllDirectories)(DWORD DirectoryFlags);
+
+#define MY_LOAD_LIBRARY_SEARCH_USER_DIRS 0x400
+#define MY_LOAD_LIBRARY_SEARCH_SYSTEM32  0x800
+
+static const char * const g_Dlls =
+  #ifndef _CONSOLE
+  "UXTHEME\0"
+  #endif
+  "USERENV\0"
+  "SETUPAPI\0"
+  "APPHELP\0"
+  "PROPSYS\0"
+  "DWMAPI\0"
+  "CRYPTBASE\0"
+  "OLEACC\0"
+  "CLBCATQ\0"
+  "VERSION\0"
+  ;
+
+#endif
+
+// #define MY_CAST_FUNC  (void(*)())
+#define MY_CAST_FUNC  
+
+void My_SetDefaultDllDirectories()
+{
+  #ifndef UNDER_CE
+  
+    OSVERSIONINFO vi;
+    vi.dwOSVersionInfoSize = sizeof(vi);
+    if (!GetVersionEx(&vi) || vi.dwMajorVersion != 6 || vi.dwMinorVersion != 0)
+    {
+      Func_SetDefaultDllDirectories setDllDirs = (Func_SetDefaultDllDirectories)
+          MY_CAST_FUNC GetProcAddress(GetModuleHandle(TEXT("kernel32.dll")), "SetDefaultDllDirectories");
+      if (setDllDirs)
+        if (setDllDirs(MY_LOAD_LIBRARY_SEARCH_SYSTEM32 | MY_LOAD_LIBRARY_SEARCH_USER_DIRS))
+          return;
+    }
+
+  #endif
+}
+
+
+void LoadSecurityDlls()
+{
+  #ifndef UNDER_CE
+  
+  wchar_t buf[MAX_PATH + 100];
+
+  {
+    // at Vista (ver 6.0) : CoCreateInstance(CLSID_ShellLink, ...) doesn't work after SetDefaultDllDirectories() : Check it ???
+    OSVERSIONINFO vi;
+    vi.dwOSVersionInfoSize = sizeof(vi);
+    if (!GetVersionEx(&vi) || vi.dwMajorVersion != 6 || vi.dwMinorVersion != 0)
+    {
+      Func_SetDefaultDllDirectories setDllDirs = (Func_SetDefaultDllDirectories)
+          MY_CAST_FUNC GetProcAddress(GetModuleHandle(TEXT("kernel32.dll")), "SetDefaultDllDirectories");
+      if (setDllDirs)
+        if (setDllDirs(MY_LOAD_LIBRARY_SEARCH_SYSTEM32 | MY_LOAD_LIBRARY_SEARCH_USER_DIRS))
+          return;
+    }
+  }
+
+  {
+    unsigned len = GetSystemDirectoryW(buf, MAX_PATH + 2);
+    if (len == 0 || len > MAX_PATH)
+      return;
+  }
+  {
+    const char *dll;
+    unsigned pos = (unsigned)lstrlenW(buf);
+
+    if (buf[pos - 1] != '\\')
+      buf[pos++] = '\\';
+    
+    for (dll = g_Dlls; dll[0] != 0;)
+    {
+      unsigned k = 0;
+      for (;;)
+      {
+        char c = *dll++;
+        buf[pos + k] = (Byte)c;
+        k++;
+        if (c == 0)
+          break;
+      }
+
+      lstrcatW(buf, L".dll");
+      LoadLibraryExW(buf, NULL, LOAD_WITH_ALTERED_SEARCH_PATH);
+    }
+  }
+  
+  #endif
+}
+
+#endif