Re: ext4 info leak in creation times in latest mainline

[Theodore Ts'o]

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
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