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From:   Sargun Dhillon <sargun@sargun.me>
Date:   Thu, 19 Dec 2019 21:21:23 -0800
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Subject: Re: [PATCH v4 2/5] pid: Add PIDFD_IOCTL_GETFD to fetch file
 descriptors from processes
To:     Andy Lutomirski <luto@kernel.org>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Linux Containers <containers@lists.linux-foundation.org>,
        Linux API <linux-api@vger.kernel.org>,
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        Christian Brauner <christian.brauner@ubuntu.com>,
        Oleg Nesterov <oleg@redhat.com>,
        Al Viro <viro@zeniv.linux.org.uk>,
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On Thu, Dec 19, 2019 at 5:43 PM Andy Lutomirski <luto@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