From mboxrd@z Thu Jan  1 00:00:00 1970
From: Theodore Ts'o <tytso@mit.edu>
Subject: Re: ext4 info leak in creation times in latest mainline
Date: Sun, 16 Feb 2014 19:01:17 -0500
Message-ID: <20140217000117.GC12947@thunk.org>
References: <5300DEC5.2080908@oracle.com>
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Cc: Kalpak Shah <kalpak@clusterfs.com>,
	Andreas Dilger <adilger@clusterfs.com>,
	linux-ext4@vger.kernel.org, LKML <linux-kernel@vger.kernel.org>
To: Vegard Nossum <vegard.nossum@oracle.com>
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On Sun, Feb 16, 2014 at 04:52:37PM +0100, Vegard Nossum wrote:
> There seems to be a bug in ext4 where the i_crtime of struct
> ext4_inode_info is not initialised, so (some) creation times contain
> essentially random values....
> 
> I don't know if it's relevant, but the filesystem is actually ext3
> mounted using ext4. It's 100% reproducible for me, so I can test
> patches.

Thanks for the bug report.  I see the problem; it was indeed relevant
that this was an ext3 file systmem mounted as ext4.  The first time
when an ext3 inode is read by ext4, i_extra_isize is too small, and so
there is no i_crtime field.  The bug is in EXT4_EINODE_GET_XTIME() (in
ext4.h, where it is leaving ei->i_crtime.tv_sec uninitialized.

It's an easy fix.  I'll send out a patch shortly.

Cheers,

						- Ted