/// <summary>
/// The function gets the elevation information of the current process. It
/// dictates whether the process is elevated or not. Token elevation is only
/// available on Windows Vista and newer operating systems, thus
/// IsProcessElevated throws a C++ exception if it is called on systems prior
/// to Windows Vista. It is not appropriate to use this function to determine
/// whether a process is run as administartor.
/// </summary>
/// <returns>
/// Returns true if the process is elevated. Returns false if it is not.
/// </returns>
/// <exception cref="System.ComponentModel.Win32Exception">
/// When any native Windows API call fails, the function throws a Win32Exception
/// with the last error code.
/// </exception>
/// <remarks>
/// TOKEN_INFORMATION_CLASS provides TokenElevationType to check the elevation
/// type (TokenElevationTypeDefault / TokenElevationTypeLimited /
/// TokenElevationTypeFull) of the process. It is different from TokenElevation
/// in that, when UAC is turned off, elevation type always returns
/// TokenElevationTypeDefault even though the process is elevated (Integrity
/// Level == High). In other words, it is not safe to say if the process is
/// elevated based on elevation type. Instead, we should use TokenElevation.
/// </remarks>
public static bool IsProcessElevated()
{
bool fIsElevated = false;
SafeTokenHandle hToken = null;
int cbTokenElevation = 0;
IntPtr pTokenElevation = IntPtr.Zero;
try
{
// Open the access token of the current process with TOKEN_QUERY.
if (!NativeMethods.OpenProcessToken(Process.GetCurrentProcess().Handle,
NativeMethods.TOKEN_QUERY, out hToken))
{
throw new Win32Exception();
}
// Allocate a buffer for the elevation information.
cbTokenElevation = Marshal.SizeOf(typeof(TOKEN_ELEVATION));
pTokenElevation = Marshal.AllocHGlobal(cbTokenElevation);
if (pTokenElevation == IntPtr.Zero)
{
throw new Win32Exception();
}
// Retrieve token elevation information.
if (!NativeMethods.GetTokenInformation(hToken,
TOKEN_INFORMATION_CLASS.TokenElevation, pTokenElevation,
cbTokenElevation, out cbTokenElevation))
{
// When the process is run on operating systems prior to Windows
// Vista, GetTokenInformation returns false with the error code
// ERROR_INVALID_PARAMETER because TokenElevation is not supported
// on those operating systems.
throw new Win32Exception();
}
// Marshal the TOKEN_ELEVATION struct from native to .NET object.
TOKEN_ELEVATION elevation = (TOKEN_ELEVATION)Marshal.PtrToStructure(
pTokenElevation, typeof(TOKEN_ELEVATION));
// TOKEN_ELEVATION.TokenIsElevated is a non-zero value if the token
// has elevated privileges; otherwise, a zero value.
fIsElevated = (elevation.TokenIsElevated != 0);
}
finally
{
// Centralized cleanup for all allocated resources.
if (hToken != null)
{
hToken.Close();
hToken = null;
}
if (pTokenElevation != IntPtr.Zero)
{
Marshal.FreeHGlobal(pTokenElevation);
pTokenElevation = IntPtr.Zero;
cbTokenElevation = 0;
}
}
return(fIsElevated);
}
/// <summary>
/// 此函数获取当前进程的权限提升信息。它由此进程是否进行了权限提升所
/// 决定。令牌权限提升只有在Windows Vista及后续版本的Windows中有效。所以在
/// Windows Vista之前的版本中执行IsProcessElevated， 它会抛出一个C++异常。
/// 此函数并不适用于检测是否此进程以管理员身份运行。
/// </summary>
/// <returns>
/// 如果此进程的权限已被提升，返回TRUE，反之则返回FALSE。
/// </returns>
/// <exception cref="System.ComponentModel.Win32Exception">
/// 如果任何原生的Windows API函数出错，此函数会抛出一个包含最后错误代码的Win32Exception。
/// </exception>
/// <remarks>
/// TOKEN_INFORMATION_CLASS提供了TokenElevationType以便对当前进程的提升
/// 类型（TokenElevationTypeDefault / TokenElevationTypeLimited /
/// TokenElevationTypeFull）进行检测。 它和TokenElevation的不同之处在于：当UAC
/// 关闭时，即使当前进程已经被提升(完整性级别 == 高)，权限提升类型总是返回
/// TokenElevationTypeDefault。换而言之，以此来确认当前线程的提升类型是不安全的。
/// 相对的，我们应该使用TokenElevation。
/// </remarks>
internal bool IsProcessElevated()
{
bool fIsElevated = false;
SafeTokenHandle hToken = null;
int cbTokenElevation = 0;
IntPtr pTokenElevation = IntPtr.Zero;
try
{
// 使用TOKEN_QUERY打开进程主访问令牌
if (!NativeMethod.OpenProcessToken(Process.GetCurrentProcess().Handle,
NativeMethod.TOKEN_QUERY, out hToken))
{
throw new Win32Exception();
}
// 为提升信息分配内存
cbTokenElevation = Marshal.SizeOf(typeof(TOKEN_ELEVATION));
pTokenElevation = Marshal.AllocHGlobal(cbTokenElevation);
if (pTokenElevation == IntPtr.Zero)
{
throw new Win32Exception();
}
// 获取令牌提升信息
if (!NativeMethod.GetTokenInformation(hToken,
TOKEN_INFORMATION_CLASS.TokenElevation, pTokenElevation,
cbTokenElevation, out cbTokenElevation))
{
// 当进程运行于Windows Vista之前的系统中，GetTokenInformation返回
// FALSE和错误码ERROR_INVALID_PARAMETER。这是由于这些操作系统不支
// 持TokenElevation。
throw new Win32Exception();
}
// 转换TOKEN_ELEVATION结构（从原生到.Net）
TOKEN_ELEVATION elevation = (TOKEN_ELEVATION)Marshal.PtrToStructure(
pTokenElevation, typeof(TOKEN_ELEVATION));
// 如果令牌权限已经被提升，TOKEN_ELEVATION.TokenIsElevated是一个非0值
// 反之则为0
fIsElevated = (elevation.TokenIsElevated != 0);
}
finally
{
// 集中清理所有已分配的内存资源
if (hToken != null)
{
hToken.Close();
hToken = null;
}
if (pTokenElevation != IntPtr.Zero)
{
Marshal.FreeHGlobal(pTokenElevation);
pTokenElevation = IntPtr.Zero;
cbTokenElevation = 0;
}
}
return(fIsElevated);
}
