Re: A 2.4.[57] kernel crypto problem
On Mon, Jan 07, 2002 at 03:09:07PM +0000, Alexander Clouter wrote:
> On Jan 06, Pavel Minev Penev wrote:
> >
> > 1. Generate billions of passwords.
> > For each of them:
> > 1. Setup a loop device.
> > 2. Read the block after the 1024-th byte and check it
> > for Ext2/Ext3's magic ID.
> > If the ID matches:
> > 1. Print the password.
> > 3. Deconfigure the loop device.
> > The brute-forcer works fine for short periods of time.
> >
> > I've tried this on kernels 2.4.15 and 2.4.17, it's all the same
> > (although the 2.4.17 Changelog says about a number of bug-fixes in the
> > loop-back driver).
> >
> > I was wondering if you could tell me about any known or unknown problems
> > with the kernel crypto, or help me realise my stupidity.
> >
> there are only 8 loop devices....do you know this?
Yes. What makes you think I don't?
> Another thing (which has already been mentioned) is that you may be not
> closing the tasks properly, and then loop gets very upset as it hasn't been
> shutdown properly....or something :) You may of found a race condition....
After running the brute-forcer for short the loop device seems
absolutely normal. `losetup` reports it as unassigned, I can mount
volumes through it, etc. I took the code from `losetup` (lomount.c), so
I suppose the problem is elsewhere. Only I don't know how to
investigate.
--
Pav
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