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

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 @@
	1	/* DllSecur.c -- DLL loading security
	2	2021-12-25 : Igor Pavlov : Public domain */
	3
	4	#include "Precomp.h"
	5
	6	#ifdef _WIN32
	7
	8	#include <Windows.h>
	9
	10	#include "DllSecur.h"
	11
	12	#ifndef UNDER_CE
	13
	14	typedef BOOL (WINAPI *Func_SetDefaultDllDirectories)(DWORD DirectoryFlags);
	15
	16	#define MY_LOAD_LIBRARY_SEARCH_USER_DIRS 0x400
	17	#define MY_LOAD_LIBRARY_SEARCH_SYSTEM32 0x800
	18
	19	static const char * const g_Dlls =
	20	#ifndef _CONSOLE
	21	"UXTHEME\0"
	22	#endif
	23	"USERENV\0"
	24	"SETUPAPI\0"
	25	"APPHELP\0"
	26	"PROPSYS\0"
	27	"DWMAPI\0"
	28	"CRYPTBASE\0"
	29	"OLEACC\0"
	30	"CLBCATQ\0"
	31	"VERSION\0"
	32	;
	33
	34	#endif
	35
	36	// #define MY_CAST_FUNC (void(*)())
	37	#define MY_CAST_FUNC
	38
	39	void My_SetDefaultDllDirectories()
	40	{
	41	#ifndef UNDER_CE
	42
	43	OSVERSIONINFO vi;
	44	vi.dwOSVersionInfoSize = sizeof(vi);
	45	if (!GetVersionEx(&vi) \|\| vi.dwMajorVersion != 6 \|\| vi.dwMinorVersion != 0)
	46	{
	47	Func_SetDefaultDllDirectories setDllDirs = (Func_SetDefaultDllDirectories)
	48	MY_CAST_FUNC GetProcAddress(GetModuleHandle(TEXT("kernel32.dll")), "SetDefaultDllDirectories");
	49	if (setDllDirs)
	50	if (setDllDirs(MY_LOAD_LIBRARY_SEARCH_SYSTEM32 \| MY_LOAD_LIBRARY_SEARCH_USER_DIRS))
	51	return;
	52	}
	53
	54	#endif
	55	}
	56
	57
	58	void LoadSecurityDlls()
	59	{
	60	#ifndef UNDER_CE
	61
	62	wchar_t buf[MAX_PATH + 100];
	63
	64	{
	65	// at Vista (ver 6.0) : CoCreateInstance(CLSID_ShellLink, ...) doesn't work after SetDefaultDllDirectories() : Check it ???
	66	OSVERSIONINFO vi;
	67	vi.dwOSVersionInfoSize = sizeof(vi);
	68	if (!GetVersionEx(&vi) \|\| vi.dwMajorVersion != 6 \|\| vi.dwMinorVersion != 0)
	69	{
	70	Func_SetDefaultDllDirectories setDllDirs = (Func_SetDefaultDllDirectories)
	71	MY_CAST_FUNC GetProcAddress(GetModuleHandle(TEXT("kernel32.dll")), "SetDefaultDllDirectories");
	72	if (setDllDirs)
	73	if (setDllDirs(MY_LOAD_LIBRARY_SEARCH_SYSTEM32 \| MY_LOAD_LIBRARY_SEARCH_USER_DIRS))
	74	return;
	75	}
	76	}
	77
	78	{
	79	unsigned len = GetSystemDirectoryW(buf, MAX_PATH + 2);
	80	if (len == 0 \|\| len > MAX_PATH)
	81	return;
	82	}
	83	{
	84	const char *dll;
	85	unsigned pos = (unsigned)lstrlenW(buf);
	86
	87	if (buf[pos - 1] != '\\')
	88	buf[pos++] = '\\';
	89
	90	for (dll = g_Dlls; dll[0] != 0;)
	91	{
	92	unsigned k = 0;
	93	for (;;)
	94	{
	95	char c = *dll++;
	96	buf[pos + k] = (Byte)c;
	97	k++;
	98	if (c == 0)
	99	break;
	100	}
	101
	102	lstrcatW(buf, L".dll");
	103	LoadLibraryExW(buf, NULL, LOAD_WITH_ALTERED_SEARCH_PATH);
	104	}
	105	}
	106
	107	#endif
	108	}
	109
	110	#endif