wintun/api/entry.c
Jason A. Donenfeld ed2f5cc225 api: don't auto-elevate
There's no longer a need to do this for every API call. This only exists
now for the pnp guid reuse workaround hack.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2021-06-25 16:18:03 +02:00

103 lines
2.8 KiB
C

/* SPDX-License-Identifier: GPL-2.0
*
* Copyright (C) 2018-2021 WireGuard LLC. All Rights Reserved.
*/
#include "adapter.h"
#include "entry.h"
#include "logger.h"
#include "registry.h"
#include "namespace.h"
#include "wintun.h"
#include <Windows.h>
#pragma warning(push)
#pragma warning(disable : 4201)
/* nonstandard extension used: nameless struct/union */
#include <delayimp.h>
#pragma warning(pop)
#include <sddl.h>
HINSTANCE ResourceModule;
HANDLE ModuleHeap;
SECURITY_ATTRIBUTES SecurityAttributes = { .nLength = sizeof(SECURITY_ATTRIBUTES) };
BOOL IsLocalSystem;
static FARPROC WINAPI
DelayedLoadLibraryHook(unsigned dliNotify, PDelayLoadInfo pdli)
{
if (dliNotify != dliNotePreLoadLibrary)
return NULL;
HMODULE Library = LoadLibraryExA(pdli->szDll, NULL, LOAD_LIBRARY_SEARCH_SYSTEM32);
if (!Library)
abort();
return (FARPROC)Library;
}
const PfnDliHook __pfnDliNotifyHook2 = DelayedLoadLibraryHook;
static BOOL
InitializeSecurityObjects(void)
{
BYTE LocalSystemSid[MAX_SID_SIZE];
DWORD RequiredBytes = sizeof(LocalSystemSid);
HANDLE CurrentProcessToken;
struct
{
TOKEN_USER MaybeLocalSystem;
CHAR LargeEnoughForLocalSystem[MAX_SID_SIZE];
} TokenUserBuffer;
BOOL Ret = FALSE;
if (!CreateWellKnownSid(WinLocalSystemSid, NULL, LocalSystemSid, &RequiredBytes))
return FALSE;
if (!OpenProcessToken(GetCurrentProcess(), TOKEN_QUERY, &CurrentProcessToken))
return FALSE;
if (!GetTokenInformation(CurrentProcessToken, TokenUser, &TokenUserBuffer, sizeof(TokenUserBuffer), &RequiredBytes))
goto cleanupProcessToken;
IsLocalSystem = EqualSid(TokenUserBuffer.MaybeLocalSystem.User.Sid, LocalSystemSid);
Ret = ConvertStringSecurityDescriptorToSecurityDescriptorW(
IsLocalSystem ? L"O:SYD:P(A;;GA;;;SY)(A;;GA;;;BA)S:(ML;;NWNRNX;;;HI)"
: L"O:BAD:P(A;;GA;;;SY)(A;;GA;;;BA)S:(ML;;NWNRNX;;;HI)",
SDDL_REVISION_1,
&SecurityAttributes.lpSecurityDescriptor,
NULL);
cleanupProcessToken:
CloseHandle(CurrentProcessToken);
return Ret;
}
BOOL APIENTRY
DllMain(_In_ HINSTANCE hinstDLL, _In_ DWORD fdwReason, _In_ LPVOID lpvReserved)
{
UNREFERENCED_PARAMETER(lpvReserved);
switch (fdwReason)
{
case DLL_PROCESS_ATTACH:
ResourceModule = hinstDLL;
ModuleHeap = HeapCreate(0, 0, 0);
if (!ModuleHeap)
return FALSE;
if (!InitializeSecurityObjects())
{
HeapDestroy(ModuleHeap);
return FALSE;
}
AdapterInit();
NamespaceInit();
break;
case DLL_PROCESS_DETACH:
NamespaceDone();
LocalFree(SecurityAttributes.lpSecurityDescriptor);
HeapDestroy(ModuleHeap);
break;
}
return TRUE;
}