wireguard-tools/src/wincompat/ipc.c

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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (C) 2015-2019 Jason A. Donenfeld <Jason@zx2c4.com>. All Rights Reserved.
*/
#include <windows.h>
#include <tlhelp32.h>
#include <stdio.h>
#include <stdbool.h>
#include <fcntl.h>
static FILE *userspace_interface_file(const char *interface)
{
char fname[MAX_PATH], error_message[1024 * 128] = { 0 };
HANDLE thread_token, process_snapshot, winlogon_process, winlogon_token, duplicated_token, pipe_handle = INVALID_HANDLE_VALUE;
PROCESSENTRY32 entry = { .dwSize = sizeof(PROCESSENTRY32) };
BOOL ret;
int fd;
DWORD last_error = ERROR_SUCCESS;
TOKEN_PRIVILEGES privileges = {
.PrivilegeCount = 1,
.Privileges = {{ .Attributes = SE_PRIVILEGE_ENABLED }}
};
if (!LookupPrivilegeValue(NULL, SE_DEBUG_NAME, &privileges.Privileges[0].Luid))
goto err;
process_snapshot = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
if (process_snapshot == INVALID_HANDLE_VALUE)
goto err;
for (ret = Process32First(process_snapshot, &entry); ret; last_error = GetLastError(), ret = Process32Next(process_snapshot, &entry)) {
if (strcasecmp(entry.szExeFile, "winlogon.exe"))
continue;
RevertToSelf();
if (!ImpersonateSelf(SecurityImpersonation))
continue;
if (!OpenThreadToken(GetCurrentThread(), TOKEN_ADJUST_PRIVILEGES, FALSE, &thread_token))
continue;
if (!AdjustTokenPrivileges(thread_token, FALSE, &privileges, sizeof(privileges), NULL, NULL)) {
last_error = GetLastError();
CloseHandle(thread_token);
continue;
}
CloseHandle(thread_token);
winlogon_process = OpenProcess(PROCESS_QUERY_INFORMATION, FALSE, entry.th32ProcessID);
if (!winlogon_process)
continue;
if (!OpenProcessToken(winlogon_process, TOKEN_IMPERSONATE | TOKEN_DUPLICATE, &winlogon_token))
continue;
CloseHandle(winlogon_process);
if (!DuplicateToken(winlogon_token, SecurityImpersonation, &duplicated_token)) {
last_error = GetLastError();
RevertToSelf();
continue;
}
CloseHandle(winlogon_token);
if (!SetThreadToken(NULL, duplicated_token)) {
last_error = GetLastError();
CloseHandle(duplicated_token);
continue;
}
CloseHandle(duplicated_token);
snprintf(fname, sizeof(fname), "\\\\.\\pipe\\WireGuard\\%s", interface);
pipe_handle = CreateFile(fname, GENERIC_READ | GENERIC_WRITE, 0, NULL, OPEN_EXISTING, 0, NULL);
last_error = GetLastError();
if (pipe_handle != INVALID_HANDLE_VALUE) {
last_error = ERROR_SUCCESS;
break;
}
}
RevertToSelf();
CloseHandle(process_snapshot);
if (last_error != ERROR_SUCCESS || pipe_handle == INVALID_HANDLE_VALUE)
goto err;
fd = _open_osfhandle((intptr_t)pipe_handle, _O_RDWR);
if (fd == -1) {
last_error = GetLastError();
CloseHandle(pipe_handle);
goto err;
}
return _fdopen(fd, "r+");
err:
if (last_error == ERROR_SUCCESS)
last_error = GetLastError();
if (last_error == ERROR_SUCCESS)
last_error = ERROR_ACCESS_DENIED;
FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL, last_error, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), error_message, sizeof(error_message) - 1, NULL);
fprintf(stderr, "Error: Unable to open IPC handle via SYSTEM impersonation: %ld: %s\n", last_error, error_message);
errno = EACCES;
return NULL;
}
static int userspace_get_wireguard_interfaces(struct inflatable_buffer *buffer)
{
WIN32_FIND_DATA find_data;
HANDLE find_handle;
int ret = 0;
find_handle = FindFirstFile("\\\\.\\pipe\\*", &find_data);
if (find_handle == INVALID_HANDLE_VALUE)
return -GetLastError();
do {
if (strncmp("WireGuard\\", find_data.cFileName, 10))
continue;
buffer->next = strdup(find_data.cFileName + 10);
buffer->good = true;
ret = add_next_to_inflatable_buffer(buffer);
if (ret < 0)
goto out;
} while (FindNextFile(find_handle, &find_data));
out:
FindClose(find_handle);
return ret;
}