From 919e042c8410a927d48d26a25c9dd7df737ffa43 Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@zx2c4.com>
Date: Wed, 12 Jun 2019 18:37:49 +0200
Subject: conf: manually migrate from windows.old

---
 conf/path_windows.go | 62 ++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 55 insertions(+), 7 deletions(-)

(limited to 'conf/path_windows.go')

diff --git a/conf/path_windows.go b/conf/path_windows.go
index 34e189b2..ad2d759c 100644
--- a/conf/path_windows.go
+++ b/conf/path_windows.go
@@ -7,22 +7,74 @@ package conf
 
 import (
 	"errors"
+	"log"
 	"os"
 	"path/filepath"
+	"strings"
 	"unsafe"
 
 	"golang.org/x/sys/windows"
 )
 
 //sys	coTaskMemFree(pointer uintptr) = ole32.CoTaskMemFree
-//sys	shGetKnownFolderPath(id *windows.GUID, flags uint32, token windows.Handle, path **uint16) (err error) [failretval!=0] = shell32.SHGetKnownFolderPath
+//sys	shGetKnownFolderPath(id *windows.GUID, flags uint32, token windows.Handle, path **uint16) (ret error) = shell32.SHGetKnownFolderPath
+//sys	getFileSecurity(fileName *uint16, securityInformation uint32, securityDescriptor *byte, descriptorLen uint32, requestedLen *uint32) (err error) = advapi32.GetFileSecurityW
+//sys	getSecurityDescriptorOwner(securityDescriptor *byte, sid **windows.SID, ownerDefaulted *bool) (err error) = advapi32.GetSecurityDescriptorOwner
+
 var folderIDLocalAppData = windows.GUID{0xf1b32785, 0x6fba, 0x4fcf, [8]byte{0x9d, 0x55, 0x7b, 0x8e, 0x7f, 0x15, 0x70, 0x91}}
 
 const kfFlagCreate = 0x00008000
+const ownerSecurityInformation = 0x00000001
 
 var cachedConfigFileDir string
 var cachedRootDir string
 
+func maybeMigrate(c string) {
+	vol := filepath.VolumeName(c)
+	withoutVol := strings.TrimPrefix(c, vol)
+	oldRoot := filepath.Join(vol, "\\windows.old")
+	oldC := filepath.Join(oldRoot, withoutVol)
+
+	var err error
+	var sd []byte
+	reqLen := uint32(128)
+	for {
+		sd = make([]byte, reqLen)
+		//XXX: Since this takes a file path, it's technically a TOCTOU.
+		err = getFileSecurity(windows.StringToUTF16Ptr(oldRoot), ownerSecurityInformation, &sd[0], uint32(len(sd)), &reqLen)
+		if err != windows.ERROR_INSUFFICIENT_BUFFER {
+			break
+		}
+	}
+	if err == windows.ERROR_PATH_NOT_FOUND {
+		return
+	}
+	if err != nil {
+		log.Printf("Not migrating configuration from '%s' due to GetFileSecurity error: %v", oldRoot, err)
+		return
+	}
+	var defaulted bool
+	var sid *windows.SID
+	err = getSecurityDescriptorOwner(&sd[0], &sid, &defaulted)
+	if err != nil {
+		log.Printf("Not migrating configuration from '%s' due to GetSecurityDescriptorOwner error: %v", oldRoot, err)
+		return
+	}
+	if defaulted || !sid.IsWellKnown(windows.WinLocalSystemSid) {
+		sidStr, _ := sid.String()
+		log.Printf("Not migrating configuration from '%s' it is not explicitly owned by SYSTEM, but rather '%s'", oldRoot, sidStr)
+		return
+	}
+	err = windows.MoveFileEx(windows.StringToUTF16Ptr(oldC), windows.StringToUTF16Ptr(c), windows.MOVEFILE_COPY_ALLOWED)
+	if err != nil {
+		if err != windows.ERROR_FILE_NOT_FOUND && err != windows.ERROR_ALREADY_EXISTS {
+			log.Printf("Not migrating configuration from '%s' due to error when moving files: %v", oldRoot, err)
+		}
+		return
+	}
+	log.Printf("Migrated configuration from '%s'", oldRoot)
+}
+
 func tunnelConfigurationsDirectory() (string, error) {
 	if cachedConfigFileDir != "" {
 		return cachedConfigFileDir, nil
@@ -32,6 +84,7 @@ func tunnelConfigurationsDirectory() (string, error) {
 		return "", err
 	}
 	c := filepath.Join(root, "Configurations")
+	maybeMigrate(c)
 	err = os.MkdirAll(c, os.ModeDir|0700)
 	if err != nil {
 		return "", err
@@ -44,13 +97,8 @@ func RootDirectory() (string, error) {
 	if cachedRootDir != "" {
 		return cachedRootDir, nil
 	}
-	processToken, err := windows.OpenCurrentProcessToken()
-	if err != nil {
-		return "", err
-	}
-	defer processToken.Close()
 	var path *uint16
-	err = shGetKnownFolderPath(&folderIDLocalAppData, kfFlagCreate, windows.Handle(processToken), &path)
+	err := shGetKnownFolderPath(&folderIDLocalAppData, kfFlagCreate, 0, &path)
 	if err != nil {
 		return "", err
 	}
-- 
cgit v1.2.3-59-g8ed1b