linux-kernel - Re: [PATCH 4/6] ext2: tighten restrictions on inode flags

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Date:	Thu, 12 Jun 2008 03:06:29 -0600
From:	Andreas Dilger <adilger@....com>
To:	Duane Griffin <duaneg@...da.com>
Cc:	akpm@...ux-foundation.org, linux-ext4@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/6] ext2: tighten restrictions on inode flags

On Jun 11, 2008  01:04 +0100, Duane Griffin wrote:
> At the moment there are few restrictions on which flags may be set on which
> inodes. Specifically DIRSYNC may only be set on directories and IMMUTABLE
> and APPEND may not be set on links. Tighten that to disallow TOPDIR being
> set on non-directories and SECRM, UNRM, COMPR, SYNC, DIRTY, COMPRBLK,
> NOCOMP, ECOMPR, INDEX, JOURNAL_DATA and NOTAIL being set on anything but
> regular files or directories.
> 
> Introduce a flags masking function which masks flags based on mode and use
> it during inode creation and when flags are set via the ioctl to facilitate
> future consistency.

This second set of patches is missing out on the presence of the
"EXT2_FL_USER_MODIFIABLE" mask in ext2_ioctl(EXT2_IOC_SETFLAGS).  This is
what prevents "unsettable" flags from being set from userspace.

I don't have any objection to additional filtering to avoid setting the
USER_MODIFIABLE flags on special files.

Cheers, Andreas
--
Andreas Dilger
Sr. Staff Engineer, Lustre Group
Sun Microsystems of Canada, Inc.

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