wintun: Introduce new package for obscuring Windows bits

1 files changed, 461 insertions, 0 deletions

diff --git a/tun/wintun/wintun_windows.go b/tun/wintun/wintun_windows.go
new file mode 100644
index 0000000..1413c24
--- /dev/null
+++ b/tun/wintun/wintun_windows.go
@@ -0,0 +1,461 @@
+/* SPDX-License-Identifier: MIT
+ *
+ * Copyright (C) 2019 WireGuard LLC. All Rights Reserved.
+ */
+
+package wintun
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+	"syscall"
+	"time"
+	"unsafe"
+
+	"git.zx2c4.com/wireguard-go/tun/wintun/guid"
+	"git.zx2c4.com/wireguard-go/tun/wintun/setupapi"
+	"golang.org/x/sys/windows"
+	"golang.org/x/sys/windows/registry"
+)
+
+type Wintun windows.GUID
+
+var deviceClassNetGUID = windows.GUID{0x4d36e972, 0xe325, 0x11ce, [8]byte{0xbf, 0xc1, 0x08, 0x00, 0x2b, 0xe1, 0x03, 0x18}}
+
+const TUN_HWID = "Wintun"
+
+//
+// GetInterface finds interface ID by name.
+//
+// hwndParent is a handle to the top-level window to use for any user
+// interface that is related to non-device-specific actions (such as a select-
+// device dialog box that uses the global class driver list). This handle is
+// optional and can be 0. If a specific top-level window is not required, set
+// hwndParent to 0.
+//
+// Function returns interface ID when the interface was found, or nil
+// otherwise.
+//
+func GetInterface(ifname string, hwndParent uintptr) (*Wintun, error) {
+	// Create a list of network devices.
+	devInfoList, err := setupapi.SetupDiGetClassDevsEx(&deviceClassNetGUID, "", hwndParent, setupapi.DIGCF_PRESENT, setupapi.DevInfo(0), "")
+	if err != nil {
+		return nil, err
+	}
+	defer devInfoList.Close()
+
+	// Retrieve information associated with a device information set.
+	// TODO: Is this really necessary?
+	_, err = devInfoList.GetDeviceInfoListDetail()
+	if err != nil {
+		return nil, err
+	}
+
+	// TODO: If we're certain we want case-insensitive name comparison, please document the rationale.
+	ifname = strings.ToLower(ifname)
+
+	// Iterate.
+	for index := 0; ; index++ {
+		// Get the device from the list.
+		deviceData, err := devInfoList.EnumDeviceInfo(index)
+		if err != nil {
+			if errWin, ok := err.(syscall.Errno); ok && errWin == 259 /*ERROR_NO_MORE_ITEMS*/ {
+				break
+			}
+			// Something is wrong with this device. Skip it.
+			continue
+		}
+
+		// Get interface ID.
+		ifid, err := getInterfaceId(devInfoList, deviceData, 1)
+		if err != nil {
+			// Something is wrong with this device. Skip it.
+			continue
+		}
+
+		// Get interface name.
+		ifname2, err := ((*Wintun)(ifid)).GetInterfaceName()
+		if err != nil {
+			// Something is wrong with this device. Skip it.
+			continue
+		}
+
+		if ifname == strings.ToLower(ifname2) {
+			// Interface name found.
+			return (*Wintun)(ifid), nil
+		}
+	}
+
+	return nil, nil
+}
+
+//
+// CreateInterface creates a TUN interface.
+//
+// description is a string that supplies the text description of the device.
+// description is optional and can be "".
+//
+// hwndParent is a handle to the top-level window to use for any user
+// interface that is related to non-device-specific actions (such as a select-
+// device dialog box that uses the global class driver list). This handle is
+// optional and can be 0. If a specific top-level window is not required, set
+// hwndParent to 0.
+//
+// Function returns the network interface ID and a flag if reboot is required.
+//
+func CreateInterface(description string, hwndParent uintptr) (*Wintun, bool, error) {
+	// Create an empty device info set for network adapter device class.
+	devInfoList, err := setupapi.SetupDiCreateDeviceInfoListEx(&deviceClassNetGUID, hwndParent, "")
+	if err != nil {
+		return nil, false, err
+	}
+
+	// Get the device class name from GUID.
+	className, err := setupapi.SetupDiClassNameFromGuidEx(&deviceClassNetGUID, "")
+	if err != nil {
+		return nil, false, err
+	}
+
+	// Create a new device info element and add it to the device info set.
+	deviceData, err := devInfoList.CreateDeviceInfo(className, &deviceClassNetGUID, description, hwndParent, setupapi.DICD_GENERATE_ID)
+	if err != nil {
+		return nil, false, err
+	}
+
+	// Set a device information element as the selected member of a device information set.
+	err = devInfoList.SetSelectedDevice(deviceData)
+	if err != nil {
+		return nil, false, err
+	}
+
+	// Set Plug&Play device hardware ID property.
+	hwid, err := syscall.UTF16FromString(TUN_HWID)
+	if err != nil {
+		return nil, false, err
+	}
+	err = devInfoList.SetDeviceRegistryProperty(deviceData, setupapi.SPDRP_HARDWAREID, setupapi.UTF16ToBuf(append(hwid, 0)))
+	if err != nil {
+		return nil, false, err
+	}
+
+	// Search for the driver.
+	const driverType = setupapi.SPDIT_CLASSDRIVER
+	err = devInfoList.BuildDriverInfoList(deviceData, driverType)
+	if err != nil {
+		return nil, false, err
+	}
+	defer devInfoList.DestroyDriverInfoList(deviceData, driverType)
+
+	driverDate := windows.Filetime{}
+	driverVersion := uint64(0)
+	for index := 0; ; index++ {
+		// Get a driver from the list.
+		driverData, err := devInfoList.EnumDriverInfo(deviceData, driverType, index)
+		if err != nil {
+			if errWin, ok := err.(syscall.Errno); ok && errWin == 259 /*ERROR_NO_MORE_ITEMS*/ {
+				break
+			}
+			// Something is wrong with this driver. Skip it.
+			continue
+		}
+
+		// Check the driver version first, since the check is trivial and will save us iterating over hardware IDs for any driver versioned prior our best match.
+		if driverData.IsNewer(driverDate, driverVersion) {
+			// Get driver info details.
+			driverDetailData, err := devInfoList.GetDriverInfoDetail(deviceData, driverData)
+			if err != nil {
+				// Something is wrong with this driver. Skip it.
+				continue
+			}
+
+			if driverDetailData.IsCompatible(TUN_HWID) {
+				// Matching hardware ID found. Select the driver.
+				err := devInfoList.SetSelectedDriver(deviceData, driverData)
+				if err != nil {
+					// Something is wrong with this driver. Skip it.
+					continue
+				}
+
+				driverDate = driverData.DriverDate
+				driverVersion = driverData.DriverVersion
+			}
+		}
+	}
+
+	if driverVersion == 0 {
+		return nil, false, fmt.Errorf("No driver for device \"%v\" installed", TUN_HWID)
+	}
+
+	// Call appropriate class installer.
+	err = devInfoList.CallClassInstaller(setupapi.DIF_REGISTERDEVICE, deviceData)
+	if err != nil {
+		return nil, false, err
+	}
+
+	// Register device co-installers if any.
+	devInfoList.CallClassInstaller(setupapi.DIF_REGISTER_COINSTALLERS, deviceData)
+
+	// Install interfaces if any.
+	devInfoList.CallClassInstaller(setupapi.DIF_INSTALLINTERFACES, deviceData)
+
+	var ifid *windows.GUID
+	var rebootRequired bool
+
+	// Install the device.
+	err = devInfoList.CallClassInstaller(setupapi.DIF_INSTALLDEVICE, deviceData)
+	if err == nil {
+		// Check if a system reboot is required. (Ignore errors)
+		if ret, _ := checkReboot(devInfoList, deviceData); ret {
+			rebootRequired = true
+		}
+
+		// Get network interface ID from registry. Retry for max 30sec.
+		ifid, err = getInterfaceId(devInfoList, deviceData, 30)
+	}
+
+	if err == nil {
+		return (*Wintun)(ifid), rebootRequired, nil
+	}
+
+	// The interface failed to install, or the interface ID was unobtainable. Clean-up.
+	removeDeviceParams := setupapi.SP_REMOVEDEVICE_PARAMS{
+		ClassInstallHeader: setupapi.SP_CLASSINSTALL_HEADER{
+			InstallFunction: setupapi.DIF_REMOVE,
+		},
+		Scope: setupapi.DI_REMOVEDEVICE_GLOBAL,
+	}
+	removeDeviceParams.ClassInstallHeader.Size = uint32(unsafe.Sizeof(removeDeviceParams.ClassInstallHeader))
+
+	// Set class installer parameters for DIF_REMOVE.
+	if devInfoList.SetClassInstallParams(deviceData, &removeDeviceParams.ClassInstallHeader, uint32(unsafe.Sizeof(removeDeviceParams))) == nil {
+		// Call appropriate class installer.
+		if devInfoList.CallClassInstaller(setupapi.DIF_REMOVE, deviceData) == nil {
+			// Check if a system reboot is required. (Ignore errors)
+			if ret, _ := checkReboot(devInfoList, deviceData); ret {
+				rebootRequired = true
+			}
+		}
+	}
+
+	return nil, false, err
+}
+
+//
+// DeleteInterface deletes a TUN interface.
+//
+// hwndParent is a handle to the top-level window to use for any user
+// interface that is related to non-device-specific actions (such as a select-
+// device dialog box that uses the global class driver list). This handle is
+// optional and can be 0. If a specific top-level window is not required, set
+// hwndParent to 0.
+//
+// Function returns true if the interface was found and deleted and a flag if
+// reboot is required.
+//
+func (wintun *Wintun) DeleteInterface(hwndParent uintptr) (bool, bool, error) {
+	ifid := (*windows.GUID)(wintun)
+	// Create a list of network devices.
+	devInfoList, err := setupapi.SetupDiGetClassDevsEx(&deviceClassNetGUID, "", hwndParent, setupapi.DIGCF_PRESENT, setupapi.DevInfo(0), "")
+	if err != nil {
+		return false, false, err
+	}
+	defer devInfoList.Close()
+
+	// Retrieve information associated with a device information set.
+	// TODO: Is this really necessary?
+	_, err = devInfoList.GetDeviceInfoListDetail()
+	if err != nil {
+		return false, false, err
+	}
+
+	// Iterate.
+	for index := 0; ; index++ {
+		// Get the device from the list.
+		deviceData, err := devInfoList.EnumDeviceInfo(index)
+		if err != nil {
+			if errWin, ok := err.(syscall.Errno); ok && errWin == 259 /*ERROR_NO_MORE_ITEMS*/ {
+				break
+			}
+			// Something is wrong with this device. Skip it.
+			continue
+		}
+
+		// Get interface ID.
+		ifid2, err := getInterfaceId(devInfoList, deviceData, 1)
+		if err != nil {
+			// Something is wrong with this device. Skip it.
+			continue
+		}
+
+		if ifid == ifid2 {
+			// Remove the device.
+			removeDeviceParams := setupapi.SP_REMOVEDEVICE_PARAMS{
+				ClassInstallHeader: setupapi.SP_CLASSINSTALL_HEADER{
+					InstallFunction: setupapi.DIF_REMOVE,
+				},
+				Scope: setupapi.DI_REMOVEDEVICE_GLOBAL,
+			}
+			removeDeviceParams.ClassInstallHeader.Size = uint32(unsafe.Sizeof(removeDeviceParams.ClassInstallHeader))
+
+			// Set class installer parameters for DIF_REMOVE.
+			err = devInfoList.SetClassInstallParams(deviceData, &removeDeviceParams.ClassInstallHeader, uint32(unsafe.Sizeof(removeDeviceParams)))
+			if err != nil {
+				return false, false, err
+			}
+
+			// Call appropriate class installer.
+			err = devInfoList.CallClassInstaller(setupapi.DIF_REMOVE, deviceData)
+			if err != nil {
+				return false, false, err
+			}
+
+			// Check if a system reboot is required. (Ignore errors)
+			if ret, _ := checkReboot(devInfoList, deviceData); ret {
+				return true, true, nil
+			}
+
+			return true, false, nil
+		}
+	}
+
+	return false, false, nil
+}
+
+///
+/// checkReboot checks device install parameters if a system reboot is required.
+///
+func checkReboot(deviceInfoSet setupapi.DevInfo, deviceInfoData *setupapi.SP_DEVINFO_DATA) (bool, error) {
+	devInstallParams, err := deviceInfoSet.GetDeviceInstallParams(deviceInfoData)
+	if err != nil {
+		return false, err
+	}
+
+	if (devInstallParams.Flags & (setupapi.DI_NEEDREBOOT | setupapi.DI_NEEDRESTART)) != 0 {
+		return true, nil
+	}
+
+	return false, nil
+}
+
+// getInterfaceId returns network interface ID.
+//
+// After the device is created, it might take some time before the registry
+// key is populated. numAttempts parameter specifies the number of attempts
+// to read NetCfgInstanceId value from registry. A 1sec sleep is inserted
+// between retry attempts.
+//
+// Function returns the network interface ID.
+//
+func getInterfaceId(deviceInfoSet setupapi.DevInfo, deviceInfoData *setupapi.SP_DEVINFO_DATA, numAttempts int) (*windows.GUID, error) {
+	if numAttempts < 1 {
+		return nil, fmt.Errorf("Invalid numAttempts (expected: >=1, provided: %v)", numAttempts)
+	}
+
+	// Open HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Class\<class>\<id> registry key.
+	key, err := deviceInfoSet.OpenDevRegKey(deviceInfoData, setupapi.DICS_FLAG_GLOBAL, 0, setupapi.DIREG_DRV, registry.READ)
+	if err != nil {
+		return nil, errors.New("Device-specific registry key open failed: " + err.Error())
+	}
+	defer key.Close()
+
+	for {
+		// Query the NetCfgInstanceId value. Using get_reg_string() right on might clutter the output with error messages while the registry is still being populated.
+		_, _, err = key.GetValue("NetCfgInstanceId", nil)
+		if err != nil {
+			if errWin, ok := err.(syscall.Errno); ok && errWin == windows.ERROR_FILE_NOT_FOUND {
+				numAttempts--
+				if numAttempts > 0 {
+					// Wait and retry.
+					// TODO: Wait for a cancellable event instead.
+					time.Sleep(1000 * time.Millisecond)
+					continue
+				}
+			}
+
+			return nil, errors.New("RegQueryValueEx(\"NetCfgInstanceId\") failed: " + err.Error())
+		}
+
+		// Read the NetCfgInstanceId value now.
+		value, err := getRegStringValue(key, "NetCfgInstanceId")
+		if err != nil {
+			return nil, errors.New("RegQueryStringValue(\"NetCfgInstanceId\") failed: " + err.Error())
+		}
+
+		// Convert to windows.GUID.
+		ifid, err := guid.FromString(value)
+		if err != nil {
+			return nil, fmt.Errorf("NetCfgInstanceId registry value is not a GUID (expected: \"{...}\", provided: \"%v\")", value)
+		}
+
+		return ifid, err
+	}
+}
+
+//
+// GetInterfaceName returns network interface name.
+//
+func (wintun *Wintun) GetInterfaceName() (string, error) {
+	ifid := (*windows.GUID)(wintun)
+	// Open network interface registry key.
+	key, err := registry.OpenKey(registry.LOCAL_MACHINE, fmt.Sprintf("SYSTEM\\CurrentControlSet\\Control\\Network\\%v\\%v\\Connection", guid.ToString(&deviceClassNetGUID), guid.ToString(ifid)), registry.QUERY_VALUE)
+	if err != nil {
+		return "", errors.New("Network-specific registry key open failed: " + err.Error())
+	}
+	defer key.Close()
+
+	// Get the interface name.
+	return getRegStringValue(key, "Name")
+}
+
+//
+// SetInterfaceName sets network interface name.
+//
+func (wintun *Wintun) SetInterfaceName(ifname string) error {
+	ifid := (*windows.GUID)(wintun)
+	// Open network interface registry key.
+	key, err := registry.OpenKey(registry.LOCAL_MACHINE, fmt.Sprintf("SYSTEM\\CurrentControlSet\\Control\\Network\\%v\\%v\\Connection", guid.ToString(&deviceClassNetGUID), guid.ToString(ifid)), registry.SET_VALUE)
+	if err != nil {
+		return errors.New("Network-specific registry key open failed: " + err.Error())
+	}
+	defer key.Close()
+
+	// Set the interface name.
+	return key.SetStringValue("Name", ifname)
+}
+
+//
+// getRegStringValue function reads a string value from registry.
+//
+// If the value type is REG_EXPAND_SZ the environment variables are expanded.
+// Should expanding fail, original string value and nil error are returned.
+//
+func getRegStringValue(key registry.Key, name string) (string, error) {
+	// Read string value.
+	value, valueType, err := key.GetStringValue(name)
+	if err != nil {
+		return "", err
+	}
+
+	if valueType != registry.EXPAND_SZ {
+		// Value does not require expansion.
+		return value, nil
+	}
+
+	valueExp, err := registry.ExpandString(value)
+	if err != nil {
+		// Expanding failed: return original sting value.
+		return value, nil
+	}
+
+	// Return expanded value.
+	return valueExp, nil
+}
+
+func (wintun *Wintun) SignalEventName() string {
+	return fmt.Sprintf("Global\\WINTUN_EVENT_%s", guid.ToString((*windows.GUID)(wintun)))
+}
+
+func (wintun *Wintun) DataFileName() string {
+	return fmt.Sprintf("\\\\.\\Global\\WINTUN_DEVICE_%s", guid.ToString((*windows.GUID)(wintun)))
+}
\ No newline at end of file