linux-kernel - Re: [PATCH] fs: Add new pre-allocation ioctls to vfs for compatibility with legacy xfs ioctls

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: <200901310138.34164.arnd@arndb.de>
Date:	Sat, 31 Jan 2009 01:38:32 +0100
From:	Arnd Bergmann <arnd@...db.de>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Ankit Jain <me@...itjain.org>, viro@...iv.linux.org.uk,
	hch@...radead.org, linux-fsdevel@...r.kernel.org, mfasheh@...e.com,
	joel.becker@...cle.com, ocfs2-devel@....oracle.com,
	linux-kernel@...r.kernel.org, xfs-masters@....sgi.com,
	xfs@....sgi.com
Subject: Re: [PATCH] fs: Add new pre-allocation ioctls to vfs for compatibility with legacy xfs ioctls

On Saturday 31 January 2009, Andrew Morton wrote:
> On Thu, 29 Jan 2009 02:29:11 +0530 Ankit Jain <me@...itjain.org> wrote:
> > +struct space_resv {
> > +	__s16		l_type;
> > +	__s16		l_whence;
> > +	__s64		l_start;
> > +	__s64		l_len;		/* len == 0 means until end of file */
> > +	__s32		l_sysid;
> > +	__u32		l_pid;
> > +	__s32		l_pad[4];	/* reserve area			    */
> > +};
> > +
> > +#define F_IOC_RESVSP		_IOW('X', 40, struct space_resv)
> > +#define F_IOC_RESVSP64		_IOW('X', 42, struct space_resv)
> 
> Are we sure that the aligment of l_start will be reliably the same
> across all compilers and versions thereof for all time?

On x86, the alignment differs between 32 and 64 bit, otherwise it's ok.
XFS handles the conversion for compat_ioctl in
fs/xfs/linux-2.6/xfs_ioctl32.c. If this becomes a generic file ioctl,
the conversion code should be moved to fs/compat_ioctl.c.

	Arnd <><
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/