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Re: A 2.4.[57] kernel crypto problem

On January 6, 2002 02:00 pm, Pavel Minev Penev wrote:
> Hello.
> I had a peculiar experience with a password (forgot it). It is the
> password for an AE
> S-encrypted partition on my HDD. I am using the loop
> device and the international kernel patch. I wrote a brute-forcer
> (didn't find docs and stole a lot of code from mount and losetup).
> The problem is that when I leave the brute-forcer working for a longer
> time (about 5 seconds on my 750 MHz Duron) when I press Ctrl-C (the
> brute-forcer catches the signal and tries to save the session) the
> kernel seems to deadlock. It is most probably the loop device driver.
> There are about 3304 proceses with sequential PIDs and names of
> "[loop7 <defunct>]", and are all zombies. If I try to start an app. as
> root I get something like "fork: resource temporarily unavailable", or
> "INIT: cannot fork; retrying...". Also, I can't `losetup /dev/loop7`,
> since it pauses, issuing nothing. As a normal user I seem to be able to
> work as usual. After a short period of time `init` seems to start
> functioning and switch the run-level. The brute-forcer works as follows:
> 	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 wonder
> ing if you could tell me about any known or unknown problems
> with the kernel crypto, or help me realise my stupidity.
> Comment: Sorry if this is too off-topic, I could post it to the Linux
> kernel mailing list if you prefer.

There's a warning in announce.txt in the testing directory that you might not 
have seen:

*WARNING* this is meant for the brave ones (read beta-testers ;), which
want to do some tests, and hopefully report back any problems they

Perhaps just using the standalone loop-aes module would be better in your 


It's worth a try.


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