[dm-crypt] Android dm-crypt implementation and GNU/Linux

[dm-crypt] Android dm-crypt implementation and GNU/Linux

[Hannes]

Hi everyone,

I hope this is the right place to ask: I have a dualboot between Ubuntu
Arm and Android on a mobile device of mine. The data-partition is
encrypted using Android's builtin encryption and I'd like to share it
with the Ubuntu.
I have been searching quite a bit on the net, but I can't find answers
onto whether this is possible and how. It seems to me that Android's
dm-crypt implementation is custom (no LUKS...) and implemented in VolD.
Am I right in assuming there is no way to make cryptsetup unlock the
partition?
And do you know of a standalone implementation that can decrypt the
partition on a GNU/Linux system? I have come accross bruteforce attack
program[1] that runs on a regular GNU/Linux, but I think that works
directly on the footer of the partition and doesn't have any magic
beyond that.
I thought a standalone implementation should exist somewhere, as it
seems unlikely the implementation was developed inside Android's VolD.

Thanks for your help!

Best,
Hannes

[1]
https://github.com/santoku/Santoku-Linux/blob/master/tools/android/android_bruteforce_stdcrypto/bruteforce_stdcrypto.py

Re: [dm-crypt] Android dm-crypt implementation and GNU/Linux

[Milan Broz]

On 20.4.2013 14:45, Hannes wrote:
> Hi everyone,
> 
> I hope this is the right place to ask: I have a dualboot between Ubuntu
> Arm and Android on a mobile device of mine. The data-partition is
> encrypted using Android's builtin encryption and I'd like to share it
> with the Ubuntu.
> I have been searching quite a bit on the net, but I can't find answers
> onto whether this is possible and how. It seems to me that Android's
> dm-crypt implementation is custom (no LUKS...) and implemented in VolD.
> Am I right in assuming there is no way to make cryptsetup unlock the
> partition?

Hi,

I am not sure what is Android exactly doing but it would be interesting
to check.

> And do you know of a standalone implementation that can decrypt the
> partition on a GNU/Linux system? I have come accross bruteforce attack
> program[1] that runs on a regular GNU/Linux, but I think that works
> directly on the footer of the partition and doesn't have any magic
> beyond that.

My plan is to provide better support for low-level metadata parsers
(like LUKS) for not only Linux but also other OS.
This will take some time but I am definitely interested to provide
some code for Android if possible.

Please can you create issue (enhancement request) on project page
so we will not forget about it? Thanks.
http://code.google.com/p/cryptsetup/issues/list

> I thought a standalone implementation should exist somewhere, as it
> seems unlikely the implementation was developed inside Android's VolD.

Not sure about Android but there is already several other implementations
of LUKS. No problem with it but I would prefer upstream cryptsetup can
provide something usable.

Thanks,
Milan