From: Andreas Dilger <adilger@sun.com>
Subject: Re: [PATCH 4/6] ext2: tighten restrictions on inode flags
Date: Thu, 12 Jun 2008 03:06:29 -0600
Message-ID: <20080612090629.GX3726@webber.adilger.int>
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Cc: akpm@linux-foundation.org, linux-ext4@vger.kernel.org,
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To: Duane Griffin <duaneg@dghda.com>
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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.