From: Dorjoy Chowdhury <dorjoychy111@gmail.com>
To: Aleksa Sarai <cyphar@cyphar.com>, jlayton@kernel.org
Cc: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-api@vger.kernel.org, ceph-devel@vger.kernel.org,
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shuah@kernel.org, miklos@szeredi.hu, hansg@kernel.org
Subject: Re: [PATCH v6 1/4] openat2: new OPENAT2_REGULAR flag support
Date: Thu, 16 Apr 2026 17:58:57 +0600 [thread overview]
Message-ID: <CAFfO_h5kWCYszymaY=tPAbpU=PjLFxsND+CWSYtypN4iuW+qPw@mail.gmail.com> (raw)
In-Reply-To: <2026-04-16-selfless-milky-wasps-shin-p6liRL@cyphar.com>
On Thu, Apr 16, 2026 at 5:41 PM Aleksa Sarai <cyphar@cyphar.com> wrote:
>
> On 2026-03-28, Dorjoy Chowdhury <dorjoychy111@gmail.com> wrote:
> > This flag indicates the path should be opened if it's a regular file.
> > This is useful to write secure programs that want to avoid being
> > tricked into opening device nodes with special semantics while thinking
> > they operate on regular files. This is a requested feature from the
> > uapi-group[1].
> >
> > A corresponding error code EFTYPE has been introduced. For example, if
> > openat2 is called on path /dev/null with OPENAT2_REGULAR in the flag
> > param, it will return -EFTYPE. EFTYPE is already used in BSD systems
> > like FreeBSD, macOS.
> >
> > When used in combination with O_CREAT, either the regular file is
> > created, or if the path already exists, it is opened if it's a regular
> > file. Otherwise, -EFTYPE is returned.
> >
> > When OPENAT2_REGULAR is combined with O_DIRECTORY, -EINVAL is returned
> > as it doesn't make sense to open a path that is both a directory and a
> > regular file.
> >
> > [1]: https://uapi-group.org/kernel-features/#ability-to-only-open-regular-files
> >
> > Signed-off-by: Dorjoy Chowdhury <dorjoychy111@gmail.com>
> > ---
>
> Aside from the nit below, feel free to take a
>
> Reviewed-by: Aleksa Sarai <aleksa@amutable.com>
>
Thanks for reviewing!
> > diff --git a/fs/open.c b/fs/open.c
> > index 681d405bc61e..a6f445f72181 100644
> > --- a/fs/open.c
> > +++ b/fs/open.c
> > @@ -960,7 +960,7 @@ static int do_dentry_open(struct file *f,
> > if (f->f_mapping->a_ops && f->f_mapping->a_ops->direct_IO)
> > f->f_mode |= FMODE_CAN_ODIRECT;
> >
> > - f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
> > + f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC | OPENAT2_REGULAR);
>
> It's not clear to me why you dropped this, I didn't see a review
> mentioning it either. (General note: Ideally the cover letter changelog
> would mention who suggested a change in brackets after the changelog
> line so it's easier to track where a change might've come from.)
>
Thanks for the general note. I will keep that in mind.
The review was from Jeff Layton in v5
https://lore.kernel.org/linux-fsdevel/5fcc2a6e6d92dae0601c6b3b8faa8b2f83981afb.camel@kernel.org/
" 1. OPENAT2_REGULAR leaks into f_flags - do_dentry_open() strips
open-time-only flags (O_CREAT|O_EXCL|O_NOCTTY|O_TRUNC)
but does not strip OPENAT2_REGULAR. When a regular file is
successfully opened via openat2() with this flag, the bit
persists in file->f_flags and will be returned by fcntl(fd, F_GETFL)."
I think it makes sense to strip off as OPENAT2_REGULAR is an open time
only flag (like O_CREAT and the others already), right?
Regards,
Dorjoy
next prev parent reply other threads:[~2026-04-16 11:59 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-28 17:22 [PATCH v6 0/4] OPENAT2_REGULAR flag support for openat2 Dorjoy Chowdhury
2026-03-28 17:22 ` [PATCH v6 1/4] openat2: new OPENAT2_REGULAR flag support Dorjoy Chowdhury
2026-03-30 11:49 ` Jeff Layton
2026-03-30 15:07 ` Dorjoy Chowdhury
2026-04-01 19:02 ` Jeff Layton
2026-04-04 15:17 ` Dorjoy Chowdhury
2026-04-05 23:27 ` Jeff Layton
2026-04-06 15:30 ` Dorjoy Chowdhury
2026-04-14 17:33 ` Dorjoy Chowdhury
2026-04-16 11:41 ` Aleksa Sarai
2026-04-16 11:58 ` Dorjoy Chowdhury [this message]
2026-04-16 13:05 ` Aleksa Sarai
2026-04-16 13:28 ` Jeff Layton
2026-04-16 13:52 ` Jori Koolstra
2026-04-16 14:21 ` Dorjoy Chowdhury
2026-04-16 15:03 ` Jori Koolstra
2026-04-16 15:15 ` Christian Brauner
2026-04-16 21:36 ` Jori Koolstra
2026-04-16 15:15 ` Aleksa Sarai
2026-04-16 21:42 ` Jori Koolstra
2026-04-17 7:58 ` Aleksa Sarai
2026-04-27 13:27 ` Florian Weimer
2026-04-27 14:17 ` Dorjoy Chowdhury
2026-04-27 14:29 ` Christian Brauner
2026-03-28 17:22 ` [PATCH v6 2/4] kselftest/openat2: test for OPENAT2_REGULAR flag Dorjoy Chowdhury
2026-03-28 17:22 ` [PATCH v6 3/4] sparc/fcntl.h: convert O_* flag macros from hex to octal Dorjoy Chowdhury
2026-03-28 17:22 ` [PATCH v6 4/4] mips/fcntl.h: " Dorjoy Chowdhury
2026-04-16 13:07 ` [PATCH v6 0/4] OPENAT2_REGULAR flag support for openat2 Christian Brauner
2026-04-16 15:22 ` Dorjoy Chowdhury
2026-04-20 13:20 ` Christian Brauner
2026-04-20 14:31 ` Dorjoy Chowdhury
2026-05-21 10:53 ` Christian Brauner
2026-05-21 15:49 ` Dorjoy Chowdhury
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