linux-kernel - Re: [PATCH] mm: make MEMFD_CREATE into a selectable config option

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <534f113b-546b-4795-83a1-b87b67727302@t-8ch.de>
Date:   Fri, 30 Jun 2023 21:55:47 +0200
From:   Thomas Weißschuh <thomas@...ch.de>
To:     "Darrick J. Wong" <djwong@...nel.org>
Cc:     Alexander Viro <viro@...iv.linux.org.uk>,
        Christian Brauner <brauner@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, Willy Tarreau <w@....eu>,
        Zhangjin Wu <falcon@...ylab.org>
Subject: Re: [PATCH] mm: make MEMFD_CREATE into a selectable config option

On 2023-06-30 08:32:36-0700, Darrick J. Wong wrote:
> On Fri, Jun 30, 2023 at 11:08:53AM +0200, Thomas Weißschuh wrote:
> > The memfd_create() syscall, enabled by CONFIG_MEMFD_CREATE, is useful on
> > its own even when not required by CONFIG_TMPFS or CONFIG_HUGETLBFS.
> 
> If you don't have tmpfs or hugetlbfs enabled, then what fs ends up
> backing the file returned by memfd_create()?  ramfs?

ramfs, correct.

It goes via mm/memfd.c -> mm/shmem.c -> fs/ramfs/ .

Thomas

> (Not an objection, I'm just curious...)
> 
> --D
> 
> > Split it into its own proper bool option that can be enabled by users.
> > 
> > Move that option into mm/ where the code itself also lies.
> > Also add "select" statements to CONFIG_TMPFS and CONFIG_HUGETLBFS so
> > they automatically enable CONFIG_MEMFD_CREATE as before.
> > 
> > Signed-off-by: Thomas Weißschuh <linux@...ssschuh.net>
> > ---
> >  fs/Kconfig | 5 ++---
> >  mm/Kconfig | 3 +++
> >  2 files changed, 5 insertions(+), 3 deletions(-)

> [..]