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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Tue, 24 Mar 2020 14:21:59 -0700
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Subject: Re: [PATCH RESEND v9 3/8] proc: move hide_pid, pid_gid from
 pid_namespace to proc_fs_info
To:     Alexey Gladkov <gladkov.alexey@gmail.com>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Kernel Hardening <kernel-hardening@lists.openwall.com>,
        Linux API <linux-api@vger.kernel.org>,
        Linux FS Devel <linux-fsdevel@vger.kernel.org>,
        Linux Security Module <linux-security-module@vger.kernel.org>,
        Akinobu Mita <akinobu.mita@gmail.com>,
        Alexander Viro <viro@zeniv.linux.org.uk>,
        Alexey Dobriyan <adobriyan@gmail.com>,
        Alexey Gladkov <legion@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Andy Lutomirski <luto@kernel.org>,
        Daniel Micay <danielmicay@gmail.com>,
        Djalal Harouni <tixxdz@gmail.com>,
        "Dmitry V . Levin" <ldv@altlinux.org>,
        "Eric W . Biederman" <ebiederm@xmission.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Ingo Molnar <mingo@kernel.org>,
        "J . Bruce Fields" <bfields@fieldses.org>,
        Jeff Layton <jlayton@poochiereds.net>,
        Jonathan Corbet <corbet@lwn.net>,
        Kees Cook <keescook@chromium.org>,
        Oleg Nesterov <oleg@redhat.com>
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On Tue, Mar 24, 2020 at 1:46 PM Alexey Gladkov <gladkov.alexey@gmail.com> wrote:
>
> +/* definitions for hide_pid field */
> +enum {
> +       HIDEPID_OFF       = 0,
> +       HIDEPID_NO_ACCESS = 1,
> +       HIDEPID_INVISIBLE = 2,
> +};

Should this enum be named...

>  struct proc_fs_info {
>         struct pid_namespace *pid_ns;
>         struct dentry *proc_self;        /* For /proc/self */
>         struct dentry *proc_thread_self; /* For /proc/thread-self */
> +       kgid_t pid_gid;
> +       int hide_pid;
>  };

.. and then used here instead of "int"?

Same goes for 'struct proc_fs_context' too, for that matter?

And maybe in the function declarations and definitions too? In things
like 'has_pid_permissions()' (the series adds some other cases later,
like hidepid2str() etc)

Yeah, enums and ints are kind of interchangeable in C, but even if it
wouldn't give us any more typechecking (except perhaps with sparse if
you mark it so), it would be documenting the use.

Or am I missing something?

Anyway, I continue to think the series looks fine, bnut would love to
see it in -next and perhaps comments from Al and Alexey Dobriyan..

            Linus