linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Jeff Xu <jeffxu@google.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: jeffxu@chromium.org, skhan@linuxfoundation.org,
	keescook@chromium.org, akpm@linux-foundation.org,
	dmitry.torokhov@gmail.com, dverkamp@chromium.org,
	hughd@google.com, jorgelo@chromium.org,
	linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
	linux-mm@kvack.org, jannh@google.com,
	linux-hardening@vger.kernel.org,
	kernel test robot <lkp@intel.com>
Subject: Re: [PATCH v5 3/6] mm/memfd: add MFD_NOEXEC_SEAL and MFD_EXEC
Date: Tue, 6 Dec 2022 09:48:55 -0800	[thread overview]
Message-ID: <CALmYWFvO8kKGusv8_Jwevw5pS4LwbF9G12=RthWZeHYE++ZO3Q@mail.gmail.com> (raw)
In-Reply-To: <Y49vUQKRVyquazJ2@kroah.com>

On Tue, Dec 6, 2022 at 8:35 AM Greg KH <gregkh@linuxfoundation.org> wrote:
>
> On Tue, Dec 06, 2022 at 08:26:30AM -0800, Jeff Xu wrote:
> > On Tue, Dec 6, 2022 at 8:04 AM Greg KH <gregkh@linuxfoundation.org> wrote:
> > >
> > > On Tue, Dec 06, 2022 at 03:23:55PM +0000, jeffxu@chromium.org wrote:
> > > > --- a/kernel/pid_namespace.c
> > > > +++ b/kernel/pid_namespace.c
> > > > @@ -110,6 +110,11 @@ static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns
> > > >       ns->ucounts = ucounts;
> > > >       ns->pid_allocated = PIDNS_ADDING;
> > > >
> > > > +#if defined(CONFIG_SYSCTL) && defined(CONFIG_MEMFD_CREATE)
> > > > +     ns->memfd_noexec_scope =
> > > > +             task_active_pid_ns(current)->memfd_noexec_scope;
> > > > +#endif
> > >
> > > .c files should never have #if in them.  Can't you put this in a .h file
> > > properly so that this does not get really messy over time?
> > >
> > >
> > Thanks for reviewing.
> > It seems to me that checking for CONFIG_XXX is  common in c code in
> > kernel/ path.
>
> Maybe, but please don't make it any worse if at all possible.  It's
> tough to maintain code like that.
>
> > Do you have a sample code pattern (link/function) that I can follow?
>
> Any of the zillions of #if statements in .h files :)
>
Thanks.
I will take the approach of having real/stub implementation in the h
file, and the c file  using it without a compile flag.
Please kindly let me know if this is not right.

Thanks
Jeff

> thanks,
>
> greg k-h

  reply	other threads:[~2022-12-06 17:49 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-06 15:23 [PATCH v5 0/6] mm/memfd: introduce MFD_NOEXEC_SEAL and MFD_EXEC jeffxu
2022-12-06 15:23 ` [PATCH v5 1/6] mm/memfd: add F_SEAL_EXEC jeffxu
2022-12-06 15:23 ` [PATCH v5 2/6] selftests/memfd: add tests for F_SEAL_EXEC jeffxu
2022-12-06 15:23 ` [PATCH v5 3/6] mm/memfd: add MFD_NOEXEC_SEAL and MFD_EXEC jeffxu
2022-12-06 16:04   ` Greg KH
2022-12-06 16:26     ` Jeff Xu
2022-12-06 16:35       ` Greg KH
2022-12-06 17:48         ` Jeff Xu [this message]
2022-12-06 23:24           ` Kees Cook
2022-12-06 15:23 ` [PATCH v5 4/6] mm/memfd: Add write seals when apply SEAL_EXEC to executable memfd jeffxu
2022-12-06 15:23 ` [PATCH v5 5/6] selftests/memfd: add tests for MFD_NOEXEC_SEAL MFD_EXEC jeffxu
2022-12-06 16:02   ` Greg KH
2022-12-06 15:23 ` [PATCH v5 6/6] mm/memfd: security hook for memfd_create jeffxu

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CALmYWFvO8kKGusv8_Jwevw5pS4LwbF9G12=RthWZeHYE++ZO3Q@mail.gmail.com' \
    --to=jeffxu@google.com \
    --cc=akpm@linux-foundation.org \
    --cc=dmitry.torokhov@gmail.com \
    --cc=dverkamp@chromium.org \
    --cc=gregkh@linuxfoundation.org \
    --cc=hughd@google.com \
    --cc=jannh@google.com \
    --cc=jeffxu@chromium.org \
    --cc=jorgelo@chromium.org \
    --cc=keescook@chromium.org \
    --cc=linux-hardening@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-kselftest@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=lkp@intel.com \
    --cc=skhan@linuxfoundation.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).