Reusing wintun Session variable - c

Question

I have a simple code that creates a simple layer 3 interface using the Wintun library. I want to read and write packets to this interface from a different process. While I'm able to read packets from this interface using Winsock, I'm unable to write packets to the interface using either Winsock/npcap. The only solution that worked is using the WintunSendPacket method from their library. But this method takes the Session variable as a parameter. Things that I've tried till now:-
Tried to inject packet to the interface using npcap
Attempted to create a new session variable using the Adapter obtained by using the WintunOpenAdapter function. (Results in error)
Tried to write the Session variable into a mmap using CreateFileMappingA and MapViewOfFile functions.
None of the solutions seems to be yielding any results. Any help would be much appreciated.
interface.c (gcc -I include/ interface.c -lwsock32 -lWs2_32 -liphlpapi -o interface)
/* SPDX-License-Identifier: GPL-2.0
*
* Copyright (C) 2018-2021 WireGuard LLC. All Rights Reserved.
*/
// gcc -I include/ example.c -lwsock32 -lWs2_32 -liphlpapi
#include <winsock2.h>
#include <Windows.h>
#include <ws2ipdef.h>
#include <iphlpapi.h>
#include <mstcpip.h>
#include <in6addr.h>
#include <winternl.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <sal.h>
#include <winerror.h>
#include <netioapi.h>
#include <stdint.h>
#if !defined(_Must_inspect_result_)
#define _Must_inspect_result_
#endif
#if !defined(_Return_type_success_)
#define _Return_type_success_(x)
#endif
#if !defined(_Post_writable_byte_size_)
#define _Post_writable_byte_size_(x)
#endif
#if !defined(_In_reads_bytes_)
#define _In_reads_bytes_(x)
#endif
#if !defined(_Out_writes_bytes_all_)
#define _Out_writes_bytes_all_(x)
#endif
#if !defined(LOAD_LIBRARY_SEARCH_APPLICATION_DIR)
#define LOAD_LIBRARY_SEARCH_APPLICATION_DIR 0x00000200
#endif
#if !defined(LOAD_LIBRARY_SEARCH_SYSTEM32)
#define LOAD_LIBRARY_SEARCH_SYSTEM32 0x00000800
#endif
#include "wintun.h"
#pragma comment(lib, "iphlpapi.lib")
#pragma comment(lib, "ws2_32.lib")
static WINTUN_CREATE_ADAPTER_FUNC *WintunCreateAdapter;
static WINTUN_CLOSE_ADAPTER_FUNC *WintunCloseAdapter;
static WINTUN_OPEN_ADAPTER_FUNC *WintunOpenAdapter;
static WINTUN_GET_ADAPTER_LUID_FUNC *WintunGetAdapterLUID;
static WINTUN_GET_RUNNING_DRIVER_VERSION_FUNC *WintunGetRunningDriverVersion;
static WINTUN_DELETE_DRIVER_FUNC *WintunDeleteDriver;
static WINTUN_SET_LOGGER_FUNC *WintunSetLogger;
static WINTUN_START_SESSION_FUNC *WintunStartSession;
static WINTUN_END_SESSION_FUNC *WintunEndSession;
static WINTUN_GET_READ_WAIT_EVENT_FUNC *WintunGetReadWaitEvent;
static WINTUN_RECEIVE_PACKET_FUNC *WintunReceivePacket;
static WINTUN_RELEASE_RECEIVE_PACKET_FUNC *WintunReleaseReceivePacket;
static WINTUN_ALLOCATE_SEND_PACKET_FUNC *WintunAllocateSendPacket;
static WINTUN_SEND_PACKET_FUNC *WintunSendPacket;
WINTUN_ADAPTER_HANDLE Adapter;
WINTUN_SESSION_HANDLE Session;
HMODULE Wintun;
static HMODULE InitializeWintun(void)
{
HMODULE Wintun =
LoadLibraryExW(L"wintun.dll", NULL, LOAD_LIBRARY_SEARCH_APPLICATION_DIR | LOAD_LIBRARY_SEARCH_SYSTEM32);
if (!Wintun)
return NULL;
#define X(Name) ((*(FARPROC *)&Name = GetProcAddress(Wintun, #Name)) == NULL)
if (X(WintunCreateAdapter) || X(WintunCloseAdapter) || X(WintunOpenAdapter) || X(WintunGetAdapterLUID) ||
X(WintunGetRunningDriverVersion) || X(WintunDeleteDriver) || X(WintunSetLogger) || X(WintunStartSession) ||
X(WintunEndSession) || X(WintunGetReadWaitEvent) || X(WintunReceivePacket) || X(WintunReleaseReceivePacket) ||
X(WintunAllocateSendPacket) || X(WintunSendPacket))
#undef X
{
DWORD LastError = GetLastError();
FreeLibrary(Wintun);
SetLastError(LastError);
return NULL;
}
return Wintun;
}
static void showError()
{
wchar_t err[256];
memset(err, 0, 256);
printf("%ld\n", GetLastError());
FormatMessageW(FORMAT_MESSAGE_FROM_SYSTEM, NULL, GetLastError(),
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), err, 255, NULL);
int msgboxID = MessageBoxW(NULL,
err,
(LPCWSTR)L"☠",
MB_OK);
}
void handleCleanup()
{
WintunEndSession(Session);
WintunCloseAdapter(Adapter);
FreeLibrary(Wintun);
exit(0);
}
BOOL WINAPI consoleHandler(DWORD signal)
{
if (signal == CTRL_C_EVENT)
{
handleCleanup();
}
return TRUE;
}
int main()
{
DWORD LastError;
GUID ExampleGuid = {0x4d1e55b2, 0xf16f, 0x11cf, 0x88, 0xcb, 0x00, 0x11, 0x11, 0x00, 0x00, 0x30};
DWORD Version;
MIB_UNICASTIPADDRESS_ROW AddressRow;
Wintun = InitializeWintun();
if (!Wintun)
{
printf("Failed to initialize wintun\n");
showError();
}
Adapter = WintunCreateAdapter(L"Sclera", L"Wintun", &ExampleGuid);
if (!Adapter)
{
showError();
handleCleanup();
}
InitializeUnicastIpAddressEntry(&AddressRow);
WintunGetAdapterLUID(Adapter, &AddressRow.InterfaceLuid);
AddressRow.Address.Ipv4.sin_family = AF_INET;
AddressRow.Address.Ipv4.sin_addr.S_un.S_addr = htonl((10 << 24) | (10 << 16) | (10 << 8) | (9 << 0));
AddressRow.OnLinkPrefixLength = 24;
AddressRow.DadState = IpDadStatePreferred;
LastError = CreateUnicastIpAddressEntry(&AddressRow);
if (LastError != ERROR_SUCCESS && LastError != ERROR_OBJECT_ALREADY_EXISTS)
{
showError();
handleCleanup();
}
Session = WintunStartSession(Adapter, WINTUN_MAX_RING_CAPACITY);
if (!Session)
{
showError();
handleCleanup();
}
HANDLE hMap = CreateFileMappingA(
INVALID_HANDLE_VALUE,
NULL,
PAGE_READWRITE,
0,
sizeof(WINTUN_SESSION_HANDLE),
"ScleraSessionStruct");
WINTUN_SESSION_HANDLE *sharedSession = (WINTUN_SESSION_HANDLE *)MapViewOfFile(hMap, FILE_MAP_READ | FILE_MAP_WRITE, 0, 0, 0);
if (sharedSession == NULL)
{
showError();
}
{
Sleep(INT32_MAX);
}
}
main.c (gcc -I include/ main.c -lwsock32 -lWs2_32 -liphlpapi -o main)
#include <winsock2.h>
#include <Windows.h>
#include <ws2ipdef.h>
#include <iphlpapi.h>
#include <mstcpip.h>
#include <in6addr.h>
#include <winternl.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <sal.h>
#include <winerror.h>
#include <netioapi.h>
#include <stdint.h>
#if !defined(_Must_inspect_result_)
#define _Must_inspect_result_
#endif
#if !defined(_Return_type_success_)
#define _Return_type_success_(x)
#endif
#if !defined(_Post_writable_byte_size_)
#define _Post_writable_byte_size_(x)
#endif
#if !defined(_In_reads_bytes_)
#define _In_reads_bytes_(x)
#endif
#if !defined(_Out_writes_bytes_all_)
#define _Out_writes_bytes_all_(x)
#endif
#if !defined(LOAD_LIBRARY_SEARCH_APPLICATION_DIR)
#define LOAD_LIBRARY_SEARCH_APPLICATION_DIR 0x00000200
#endif
#if !defined(LOAD_LIBRARY_SEARCH_SYSTEM32)
#define LOAD_LIBRARY_SEARCH_SYSTEM32 0x00000800
#endif
#include "wintun.h"
#pragma comment(lib, "iphlpapi.lib")
#pragma comment(lib, "ws2_32.lib")
static WINTUN_CREATE_ADAPTER_FUNC *WintunCreateAdapter;
static WINTUN_CLOSE_ADAPTER_FUNC *WintunCloseAdapter;
static WINTUN_OPEN_ADAPTER_FUNC *WintunOpenAdapter;
static WINTUN_GET_ADAPTER_LUID_FUNC *WintunGetAdapterLUID;
static WINTUN_GET_RUNNING_DRIVER_VERSION_FUNC *WintunGetRunningDriverVersion;
static WINTUN_DELETE_DRIVER_FUNC *WintunDeleteDriver;
static WINTUN_SET_LOGGER_FUNC *WintunSetLogger;
static WINTUN_START_SESSION_FUNC *WintunStartSession;
static WINTUN_END_SESSION_FUNC *WintunEndSession;
static WINTUN_GET_READ_WAIT_EVENT_FUNC *WintunGetReadWaitEvent;
static WINTUN_RECEIVE_PACKET_FUNC *WintunReceivePacket;
static WINTUN_RELEASE_RECEIVE_PACKET_FUNC *WintunReleaseReceivePacket;
static WINTUN_ALLOCATE_SEND_PACKET_FUNC *WintunAllocateSendPacket;
static WINTUN_SEND_PACKET_FUNC *WintunSendPacket;
static HMODULE InitializeWintun(void)
{
HMODULE Wintun =
LoadLibraryExW(L"wintun.dll", NULL, LOAD_LIBRARY_SEARCH_APPLICATION_DIR | LOAD_LIBRARY_SEARCH_SYSTEM32);
if (!Wintun)
return NULL;
#define X(Name) ((*(FARPROC *)&Name = GetProcAddress(Wintun, #Name)) == NULL)
if (X(WintunCreateAdapter) || X(WintunCloseAdapter) || X(WintunOpenAdapter) || X(WintunGetAdapterLUID) ||
X(WintunGetRunningDriverVersion) || X(WintunDeleteDriver) || X(WintunSetLogger) || X(WintunStartSession) ||
X(WintunEndSession) || X(WintunGetReadWaitEvent) || X(WintunReceivePacket) || X(WintunReleaseReceivePacket) ||
X(WintunAllocateSendPacket) || X(WintunSendPacket))
#undef X
{
DWORD LastError = GetLastError();
FreeLibrary(Wintun);
SetLastError(LastError);
return NULL;
}
return Wintun;
}
static void showError()
{
wchar_t err[256];
memset(err, 0, 256);
printf("%ld\n", GetLastError());
FormatMessageW(FORMAT_MESSAGE_FROM_SYSTEM, NULL, GetLastError(),
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), err, 255, NULL);
int msgboxID = MessageBoxW(NULL,
err,
(LPCWSTR)L"☠",
MB_OK);
}
int main()
{
WINTUN_ADAPTER_HANDLE Adapter;
WINTUN_SESSION_HANDLE Session;
HMODULE Wintun = InitializeWintun();
if (!Wintun)
{
printf("Failed to initialize wintun\n");
showError();
}
printf("Wintun initialized successfully....\n");
Adapter = WintunOpenAdapter(L"Sclera");
if (!Adapter)
{
showError();
}
printf("Adapter opened successfully....\n");
HANDLE hMap = CreateFileMappingA(
INVALID_HANDLE_VALUE,
NULL,
PAGE_READONLY,
0,
sizeof(WINTUN_SESSION_HANDLE),
"ScleraSessionStruct");
WINTUN_SESSION_HANDLE *sharedSession = (WINTUN_SESSION_HANDLE *)MapViewOfFile(hMap, FILE_MAP_READ, 0, 0, 0);
if (sharedSession == NULL)
{
showError();
}
else
{
printf("Wintun session variable obtained my nigga!\n");
}
printf("Session started successfully\n");
{
Sleep(INT32_MAX);
}
return 1;
}
The idea is that there will be multiple instances of the main.c code running and they will be reading/writing packets from the Wintun interface.
Note: Both programs have to be run in administrator mode