From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 65D87221F2A; Thu, 15 May 2025 09:02:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747299777; cv=none; b=jtT3/N7R/lEE94yn+UGjppwZIRM1KbH6Dto8CSCGYo2zskVUPihDna11Rw9/+WY2JP+0bwkjNE9Yy8JEubE4mXo/TgYTSZmWQNu3vajVpJ3+gPSPnA1maGWSubZOOFBx7NBrF66XRT6VF23sBp1TAvijURY8GNaln7CzE83/2JM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747299777; c=relaxed/simple; bh=DdR+iT74thckjay2jHl6JRdQgazSc4DbBO3/97MtQFI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=T15HEDIukXWlB5KwHKhNImXOriKlMM/1FT4vMBj7UqHdoxjy0Kab3Xhaqy0LfhmrObr81wxAxMGibsJRk+AG4iwMzsLIwO2k8qAzeEI1bd8piDbvsTUK/SOLRpQzQD2Q3xciCUwaunxn+rRf8Yy6PtaBHbl91tfCyzmF9IQGmwY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=HHVHIl/G; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="HHVHIl/G" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 775F2C4CEE9; Thu, 15 May 2025 09:02:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1747299775; bh=DdR+iT74thckjay2jHl6JRdQgazSc4DbBO3/97MtQFI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=HHVHIl/GQ3OfHIKWGc8LdkQdOynuN3eRK9dIFOH9AWzvAg/+YVBY38MKu8m6DIaJ8 ogZaKfyHPqx+ER/XGzvNDMaAJXfV6hrFs9q0ktQwnuejL3O9/or3b3r6zzw9MsoMlJ /FEqGnayigRX/WV/PxkJx5UYmJfSr8I8UAHI+AqvH8WkR6JLeSgXDHx4KbTPL/+Xi7 MerAdihHYW10gxdyoj2xhrd476PtlJKjWgWOPqTFDM7lf3kHaaaJzyORvTLe7T8W30 GJu+ICmU1x4ydKhmvpPyUWChoXSJGDFoFi0Io4h8hJxpz5alVnvt2mKo1RambfbR00 hdnawvTLfvo3g== Date: Thu, 15 May 2025 11:02:39 +0200 From: Christian Brauner To: Arnd Bergmann Cc: Andrey Albershteyn , Richard Henderson , Matt Turner , Russell King , Catalin Marinas , Will Deacon , Geert Uytterhoeven , Michal Simek , Thomas Bogendoerfer , "James E . J . Bottomley" , Helge Deller , Madhavan Srinivasan , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Naveen N Rao , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Yoshinori Sato , Rich Felker , John Paul Adrian Glaubitz , "David S . Miller" , Andreas Larsson , Andy Lutomirski , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Chris Zankel , Max Filippov , Alexander Viro , Jan Kara , =?utf-8?Q?Micka=C3=ABl_Sala=C3=BCn?= , =?utf-8?Q?G=C3=BCnther?= Noack , Pali =?utf-8?B?Um9ow6Fy?= , Paul Moore , James Morris , "Serge E. Hallyn" , Stephen Smalley , Ondrej Mosnacek , Tyler Hicks , Miklos Szeredi , Amir Goldstein , linux-alpha@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-m68k@lists.linux-m68k.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org, linux-api@vger.kernel.org, Linux-Arch , selinux@vger.kernel.org, ecryptfs@vger.kernel.org, linux-unionfs@vger.kernel.org, linux-xfs@vger.kernel.org, Andrey Albershteyn Subject: Re: [PATCH v5 0/7] fs: introduce file_getattr and file_setattr syscalls Message-ID: <20250515-bedarf-absagen-464773be3e72@brauner> References: <20250513-xattrat-syscall-v5-0-22bb9c6c767f@kernel.org> <399fdabb-74d3-4dd6-9eee-7884a986dab1@app.fastmail.com> Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <399fdabb-74d3-4dd6-9eee-7884a986dab1@app.fastmail.com> On Tue, May 13, 2025 at 11:53:23AM +0200, Arnd Bergmann wrote: > On Tue, May 13, 2025, at 11:17, Andrey Albershteyn wrote: > > > > > long syscall(SYS_file_getattr, int dirfd, const char *pathname, > > struct fsxattr *fsx, size_t size, unsigned int at_flags); > > long syscall(SYS_file_setattr, int dirfd, const char *pathname, > > struct fsxattr *fsx, size_t size, unsigned int at_flags); > > I don't think we can have both the "struct fsxattr" from the uapi > headers, and a variable size as an additional argument. I would > still prefer not having the extensible structure at all and just We're not going to add new interfaces that are fixed size unless for the very basic cases. I don't care if we're doing that somewhere else in the kernel but we're not doing that for vfs apis. > use fsxattr, but if you want to make it extensible in this way, > it should use a different structure (name). Otherwise adding > fields after fsx_pad[] would break the ioctl interface. Would that really be a problem? Just along the syscall simply add something like: diff --git a/fs/ioctl.c b/fs/ioctl.c index c91fd2b46a77..d3943805c4be 100644 --- a/fs/ioctl.c +++ b/fs/ioctl.c @@ -868,12 +868,6 @@ static int do_vfs_ioctl(struct file *filp, unsigned int fd, case FS_IOC_SETFLAGS: return ioctl_setflags(filp, argp); - case FS_IOC_FSGETXATTR: - return ioctl_fsgetxattr(filp, argp); - - case FS_IOC_FSSETXATTR: - return ioctl_fssetxattr(filp, argp); - case FS_IOC_GETFSUUID: return ioctl_getfsuuid(filp, argp); @@ -886,6 +880,20 @@ static int do_vfs_ioctl(struct file *filp, unsigned int fd, break; } + switch (_IOC_NR(cmd)) { + case _IOC_NR(FS_IOC_FSGETXATTR): + if (WARN_ON_ONCE(_IOC_TYPE(cmd) != _IOC_TYPE(FS_IOC_FSGETXATTR))) + return SOMETHING_SOMETHING; + /* Only handle original size. */ + return ioctl_fsgetxattr(filp, argp); + + case _IOC_NR(FFS_IOC_FSSETXATTR): + if (WARN_ON_ONCE(_IOC_TYPE(cmd) != _IOC_TYPE(FFS_IOC_FSSETXATTR))) + return SOMETHING_SOMETHING; + /* Only handle original size. */ + return ioctl_fssetxattr(filp, argp); + } + return -ENOIOCTLCMD; }