From: Aleksa Sarai <cyphar@cyphar.com>
To: Dorjoy Chowdhury <dorjoychy111@gmail.com>
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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sprasad@microsoft.com, tom@talpey.com, bharathsm@microsoft.com,
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 21:41:12 +1000 [thread overview]
Message-ID: <2026-04-16-selfless-milky-wasps-shin-p6liRL@cyphar.com> (raw)
In-Reply-To: <20260328172314.45807-2-dorjoychy111@gmail.com>
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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>
> 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.)
I would personally keep it since O_DIRECTORY is not dropped (I do find
it interesting that O_EXCL is dropped too -- you could imagine a
userspace program wanting to know that the file was opened with O_EXCL,
though it provides you very little information).
--
Aleksa Sarai
https://www.cyphar.com/
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next prev parent reply other threads:[~2026-04-16 11:41 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 [this message]
2026-04-16 11:58 ` Dorjoy Chowdhury
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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