Re: encrypting jffs2 filesystem with DM-crypt or what else?

[markus reichelt]

* emin ak <eminak71@xxxxxxxxx> wrote:

> I need to encrypt a jffs2/mtd formatted flash filesystem for an
> embedded device, Normally using a loopback interface (cryptoloop,
> DM-crypt or loop-aes) solves this problem but they are not well
> known on journalling file systems (like jffs2) because of cached
> write etc.. Also I could'nt find any guideline for encrypting
> fikesystem on a flash.

device-backed loops are ok, file-based once aren't. The cache issue
you talk about concerns writing caches of HDDs f.e., I haven't seen a
flash device with writing cache. However, in most cases writing cache
can be turned off.

Go with README in the loop-aes package. Don't use cryptoloop, it's
insecure.


> There is an ugly workaround to overcome this problem, I have placed
> an encrypted ext2 filesystem image on an normal jffs2 partition and
> mount this encrypted partition on a loopback, but this is not
> secure, consumes alot for disk space and not reliable (is'nt it?)
> Is there any other way to encrypt an jjffs2 partition, if not, what
> do you think about my ugly workaround?

You shouldn't do that. One more option is, in case you feel lucky and
space is not of great concern, ecryptfs in latest kernels. It's still
experimental but its roadmap looks promising. And they need testers
;-)


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