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loop file with partition problems

dm-crypt Giovanni Di Stasi 3 participants 5 messages Feb 29, 2012

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Giovanni Di Stasi

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#0 lore raw

Hi everyone,

I am having problems accessing a partition I have created on a file. I have never managed to mount it after reboot. I am using Debian (testing).

This is what I did:

# sudo -i
# echo aes >> /etc/modules
# echo dm_mod >> /etc/modules
# echo dm_crypt >> /etc/modules
# dd if=/dev/urandom of=.encrypted bs=1024 count=500000
# sudo cryptsetup -y create crypt .encrypted
# echo "crypt /home/giovanni/.encrypted none none" >> /etc/crypttab
# sudo mkfs.ext4 /dev/mapper/crypt
# mkdir /home/giovanni/cip
# chown giovanni:giovanni /home/giovanni/cip/
# sudo mount /dev/mapper/crypt /home/giovanni/cip
# ls /home/giovanni/cip/
# sudo umount /home/giovanni/cip
# sudo mount /dev/mapper/crypt /home/giovanni/cip

After rebooted, I don't really know how to mount my partition. I have tried this:

# sudo -i
# cryptsetup luksOpen .encrypted crypt
Device /dev/loop0 is not a valid LUKS device.

Did I lost all my data as I suspect? If so, why?

Thanks a lot,
Giovanni

#1 lore raw
Quoted 23 lines · Giovanni Di Stasi

Hi everyone,

I am having problems accessing a partition I have created on a file. I have never managed to mount it after reboot.
I am using Debian (testing).

This is what I did:

# sudo -i
# echo aes >> /etc/modules
# echo dm_mod >> /etc/modules
# echo dm_crypt >> /etc/modules
# dd if=/dev/urandom of=.encrypted bs=1024 count=500000
# sudo cryptsetup -y create crypt .encrypted
# echo "crypt /home/giovanni/.encrypted none none" >> /etc/crypttab
# sudo mkfs.ext4 /dev/mapper/crypt
# mkdir /home/giovanni/cip
# chown giovanni:giovanni /home/giovanni/cip/
# sudo mount /dev/mapper/crypt /home/giovanni/cip
# ls /home/giovanni/cip/
# sudo umount /home/giovanni/cip
# sudo mount /dev/mapper/crypt /home/giovanni/cip
Quoted 8 lines

After rebooted, I don't really know how to mount my partition. I have tried this:

# sudo -i
# cryptsetup luksOpen .encrypted crypt
Device /dev/loop0 is not a valid LUKS device.

Did I lost all my data as I suspect? If so, why?

You are confusing plain dm-crypt and LUKS. You created the crypto-container (which is not a partition but a whole decive here) as plain dm-crypt and are trying to map it as LUKS. These two are different and not compatible.

Try this:

cryptsetup create crypt .encrypted
mount /dev/mapper/crypt /home/giovanni/cip

Arno

Signature · 6 lines
Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: [email protected] 
GnuPG:  ID: 1E25338F  FP: 0C30 5782 9D93 F785 E79C  0296 797F 6B50 1E25 338F
----
One of the painful things about our time is that those who feel certainty 
are stupid, and those with any imagination and understanding are filled 
with doubt and indecision. -- Bertrand Russell
#2 lore raw
In reply to Giovanni Di Stasi

On 02/29/2012 05:26 PM, Giovanni Di Stasi wrote:

Here you are creating plain container (did you mean luksFormat in fact?)

Quoted 1 line
# sudo cryptsetup -y create crypt .encrypted

and here you are trying to open LUKS...

Quoted 1 line
# cryptsetup luksOpen .encrypted crypt

so try
sudo cryptsetup -y create crypt .encrypted

which will just recreate the mapping (create just set up mapping, it doesn't format anything)

Milan

author
#3 lore raw

Il 29/02/2012 17:41, Milan Broz ha scritto:

Quoted 8 lines · Giovanni Di Stasi

Here you are creating plain container (did you mean luksFormat in fact?)

Quoted 1 line
# sudo cryptsetup -y create crypt .encrypted

and here you are trying to open LUKS...

Quoted 1 line
# cryptsetup luksOpen .encrypted crypt
Quoted 7 lines

so try
sudo cryptsetup -y create crypt .encrypted

which will just recreate the mapping (create just set up mapping, it doesn't format anything)

Milan

Worked!! Thanks!!

But I was asked the password twice... how come?
What if I type a different password?

Thanks,
Giovanni

#4 lore raw

The -y option is useful to use initially to make sure you have the right password when you format. It causes cryptsetup to ask the password twice.

For more documentation on the options, run
cryptsetup -h
and refer to the man-page.

Arno

Quoted 28 lines · Giovanni Di Stasi

Il 29/02/2012 17:41, Milan Broz ha scritto:

Quoted 8 lines · Giovanni Di Stasi

Here you are creating plain container (did you mean luksFormat in fact?)

Quoted 1 line
# sudo cryptsetup -y create crypt .encrypted

and here you are trying to open LUKS...

Quoted 1 line
# cryptsetup luksOpen .encrypted crypt
Quoted 7 lines

so try
sudo cryptsetup -y create crypt .encrypted

which will just recreate the mapping (create just set up mapping, it doesn't format anything)

Milan

Worked!! Thanks!!

But I was asked the password twice... how come?
What if I type a different password?

Thanks,
Giovanni
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Signature · 6 lines
Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: [email protected] 
GnuPG:  ID: 1E25338F  FP: 0C30 5782 9D93 F785 E79C  0296 797F 6B50 1E25 338F
----
One of the painful things about our time is that those who feel certainty 
are stupid, and those with any imagination and understanding are filled 
with doubt and indecision. -- Bertrand Russell