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Date:   Wed, 25 Mar 2020 21:00:15 +0300
From:   Alexey Dobriyan <adobriyan@gmail.com>
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     Alexey Gladkov <gladkov.alexey@gmail.com>,
        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 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>
Subject: Re: [PATCH RESEND v9 3/8] proc: move hide_pid, pid_gid from
 pid_namespace to proc_fs_info
Message-ID: <20200325180015.GA18706@avx2>
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On Tue, Mar 24, 2020 at 02:21:59PM -0700, Linus Torvalds wrote:
> 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..

Patches are OK, except the part where "pid" is named "pidfs" and
the suffix doesn't convey any information.

	mount -t proc -o subset=pid,sysctl,misc

Reviewed-by: Alexey Dobriyan <adobriyan@gmail.com>