no encrypted filesystems in Centos 4?

General support questions including new installations
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mciann
Posts: 3
Joined: 2005/03/04 01:33:19

no encrypted filesystems in Centos 4?

Post by mciann » 2005/03/04 01:38:33

I seem to be having trouble accessing an encrypted filesystem. Can someone give me a clue as to what is going on here:

[root@dyn-136 john]# modprobe cryptoloop
[root@dyn-136 john]# modprobe twofish
[root@dyn-136 john]# losetup -e twofish-256 /dev/loop0 test
Password:
ioctl: LOOP_SET_STATUS: Invalid argument


I get the same message regardless of the encryption protocol or keysize I choose. It is as if there is something wrong with cryptoloop itself.

brian
Posts: 18
Joined: 2004/12/20 20:30:07

no encrypted filesystems in Centos 4?

Post by brian » 2005/03/04 04:20:25

I was able to use cryptloop and losetup, but only without using a keysize (ie twofish instead of twofish-256). Perhaps the upstream provider took a conservative approach to keysize?

after modprobe, try cat /proc/crypto

mciann
Posts: 3
Joined: 2005/03/04 01:33:19

Re: no encrypted filesystems in Centos 4?

Post by mciann » 2005/03/04 14:42:04

Okay, I confirmed that losetup works if you do not specifiy a keysize on the command line. My question now is - how can I tell (or specify) what my keysize is? Below is the output of cat /proc/crypto:

name : twofish
module : twofish
type : cipher
blocksize : 16
min keysize : 16
max keysize : 32


I am ssuming keysize here is in bytes. How do I use a bigger keysize than the default if I want to?

brian
Posts: 18
Joined: 2004/12/20 20:30:07

Re: no encrypted filesystems in Centos 4?

Post by brian » 2005/03/04 15:53:33

I believe that is the issue, it seems the upstream provider has taken a very conservative stance regarding keysize in their kernel modules for cryptoloop. You will probably need to investigate further.

pmjdebruijn
Posts: 9
Joined: 2005/01/05 15:38:29
Contact:

Re: no encrypted filesystems in Centos 4?

Post by pmjdebruijn » 2005/03/04 17:42:26

Yeah, without patching your kernel you probably can't use a bigger keysize...

But generally 256bit should be fine..

Regards,
Pascal de Bruijn

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