[guardian-dev] Help answering LUKS question

Nathan of Guardian nathan at guardianproject.info
Sun Jan 27 07:28:07 EST 2013

Anyone want to take at answering this question:

(please post reply on the q&a page itself)

I’m having trouble remounting an encrypted volume after rebooting my
Android device. I’m creating the encrypted volume with the following
commands for a 5MB encrypted folder residing in my sdcard:

mknod /dev/loop0 b 7 0

dd if=/dev/zero of=/mnt/sdcard/myfile bs=1000000 count=5

losetup /dev/loop0 /mnt/sdcard/myfile

echo “password” | cryptsetup -q luksFormat –key-file=- -c aes-plain

mke2fs -O uninit_bq,resize_inode,extent,dir_index -L luksdm

mkdir /mnt/sdcard/encrypted_folder

mount -o rw -t ext3 /dev/mapper/luksdm /mnt/sdcard/encrypted_folder

cryptsetup status luksdm

I then unmount it with the following commands before rebooting the device:

umount /mnt/sdcard/encrypted_folder

cryptsetup luksClose /dev/mapper/luksdm

Upon reboot, I try to mount my encrypted folder again with the following

echo “password” | cryptsetup luksOpen –key-file=- /dev/loop0 luksdm

mount -o rw -t ext3 /dev/mapper/luksdm /mnt/sdcard/encrypted_folder

cryptsetup status luksdm

However, I am informed that /dev/loop0 doesn’t exist. It seems that the
loopback device doesn’t survive a reboot. I tried to mknod it again but
that didn’t work either – after running luksOpen,/dev/mapper/luksdm
isn’t created.

May I know what I’m doing wrong?

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