[PATCH v4 2/5] pid: Add PIDFD_IOCTL_GETFD to fetch file descriptors from processes

[Sargun Dhillon]

On Thu, Dec 19, 2019 at 5:43 PM Andy Lutomirski <luto at kernel.org> wrote:
>
>
> I don't think this is MODE_READ.  By copying an fd from the task, you
> can easily change its state.
Would PTRACE_MODE_ATTACH_REALCREDS  work? I'm curious what
kind of state change you can cause by borrowing an FD?


>
> IMO it would be really nice if pidfd could act more like a capability
> here and carry a ptrace mode, for example.  But I guess it doesn't
> right now.
>
>
> --Andy