[dm-crypt] Encrypted fs in file

[dm-crypt] Encrypted fs in file

[doark]

Hello,
I wanted to make certain that I got this process right since I've never
done it before and I can't seem to find docs on the subject.

1. Cat /dev/zero into a new file till it is big enough.
2. Use cryptsetup on the file (format and open).
3. Use mkfs on the loop device.
4. Mount the loop device as if it were a block device.

Does this look correct to you?

Thanks, David

Re: [dm-crypt] Encrypted fs in file

[Matthias Schniedermeyer]

On 03.04.2016 00:07, doark@mail.com wrote:
> Hello,
> I wanted to make certain that I got this process right since I've never
> done it before and I can't seem to find docs on the subject.
> 
> 1. Cat /dev/zero into a new file till it is big enough.
> 2. Use cryptsetup on the file (format and open).
> 3. Use mkfs on the loop device.
> 4. Mount the loop device as if it were a block device.
> 
> Does this look correct to you?

Nearly.

3) Not the loop device, but the dm-device, the loop it inbetween and is 
handled automatically.

A symlink for the dm-device appears in /dev/mapper/ with the name you 
provided for the open command.

Same for 4) You mount the dm-device




-- 

Matthias

Re: [dm-crypt] Encrypted fs in file

[Sven Eschenberg]

And regarding 1):

You might want to use dd for that and /dev/urandom. (Or use /dev/zero 
and then zero out the inner device before creating the filesystem).

Regards

-Sven


Am 03.04.2016 um 10:41 schrieb Matthias Schniedermeyer:
> On 03.04.2016 00:07, doark@mail.com wrote:
>> Hello,
>> I wanted to make certain that I got this process right since I've never
>> done it before and I can't seem to find docs on the subject.
>>
>> 1. Cat /dev/zero into a new file till it is big enough.
>> 2. Use cryptsetup on the file (format and open).
>> 3. Use mkfs on the loop device.
>> 4. Mount the loop device as if it were a block device.
>>
>> Does this look correct to you?
>
> Nearly.
>
> 3) Not the loop device, but the dm-device, the loop it inbetween and is
> handled automatically.
>
> A symlink for the dm-device appears in /dev/mapper/ with the name you
> provided for the open command.
>
> Same for 4) You mount the dm-device
>
>
>
>

Re: [dm-crypt] Encrypted fs in file

[Arno Wagner]

Also refer to FAQ item 2.6
https://gitlab.com/cryptsetup/cryptsetup/wikis/FrequentlyAskedQuestions

The zeroing out of the mapped container is advisable
if this needs high security, i.e. is not just for 
experiments.

Regards,
Arno


On Sun, Apr 03, 2016 at 18:03:11 CEST, Sven Eschenberg wrote:
> And regarding 1):
> 
> You might want to use dd for that and /dev/urandom. (Or use
> /dev/zero and then zero out the inner device before creating the
> filesystem).
> 
> Regards
> 
> -Sven
> 
> 
> Am 03.04.2016 um 10:41 schrieb Matthias Schniedermeyer:
> >On 03.04.2016 00:07, doark@mail.com wrote:
> >>Hello,
> >>I wanted to make certain that I got this process right since I've never
> >>done it before and I can't seem to find docs on the subject.
> >>
> >>1. Cat /dev/zero into a new file till it is big enough.
> >>2. Use cryptsetup on the file (format and open).
> >>3. Use mkfs on the loop device.
> >>4. Mount the loop device as if it were a block device.
> >>
> >>Does this look correct to you?
> >
> >Nearly.
> >
> >3) Not the loop device, but the dm-device, the loop it inbetween and is
> >handled automatically.
> >
> >A symlink for the dm-device appears in /dev/mapper/ with the name you
> >provided for the open command.
> >
> >Same for 4) You mount the dm-device
> >
> >
> >
> >
> _______________________________________________
> dm-crypt mailing list
> dm-crypt@saout.de
> http://www.saout.de/mailman/listinfo/dm-crypt

-- 
Arno Wagner,     Dr. sc. techn., Dipl. Inform.,    Email: arno@wagner.name
GnuPG: ID: CB5D9718  FP: 12D6 C03B 1B30 33BB 13CF  B774 E35C 5FA1 CB5D 9718
----
A good decision is based on knowledge and not on numbers. -- Plato

If it's in the news, don't worry about it.  The very definition of 
"news" is "something that hardly ever happens." -- Bruce Schneier