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Create executable, automountable filesystem in a file, with password!

Terminal - Create executable, automountable filesystem in a file, with password!
dd if=/dev/zero of=T bs=1024 count=10240;mkfs.ext3 -q T;E=$(echo 'read O;mount -o loop,offset=$O F /mnt;'|base64|tr -d '\n');echo "E=\$(echo $E|base64 -d);eval \$E;exit;">F;cat <(dd if=/dev/zero bs=$(echo 9191-$(stat -c%s F)|bc) count=1) <(cat T;rm T)>>F
2013-01-31 01:38:30
User: rodolfoap
6
Create executable, automountable filesystem in a file, with password!

This is just a proof of concept: A FILE WHICH CAN AUTOMOUNT ITSELF through a SIMPLY ENCODED script. It takes advantage of the OFFSET option of mount, and uses it as a password (see that 9191? just change it to something similar, around 9k). It works fine, mounts, gets modified, updated, and can be moved by just copying it.

USAGE: SEE SAMPLE OUTPUT

The file is composed of three parts:

a) The legible script (about 242 bytes)

b) A random text fill to reach the OFFSET size (equals PASSWORD minus 242)

c) The actual filesystem

Logically, (a)+(b) = PASSWORD, that means OFFSET, and mount uses that option.

PLEASE NOTE: THIS IS NOT AN ENCRYPTED FILESYSTEM. To improve it, it can be mounted with a better encryption script and used with encfs or cryptfs. The idea was just to test the concept... with one line :)

It applies the original idea of http://www.commandlinefu.com/commands/view/7382/command-for-john-cons for encrypting the file.

The embedded bash script can be grown, of course, and the offset recalculation goes fine. I have my own version with bash --init-file to startup a bashrc with a well-defined environment, aliases, variables.

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What others think

doesnt seem to work on ubunbu, bash F just hangs

Comment by chrismccoy 120 weeks and 5 days ago

Chrismccoy: It's probably not hanging, but asking you for the offset. If not, just follow the procedure (sample output) to confirm it generated the executable base64 encoder header correctly. I'ts really simple...

Comment by rodolfoap 120 weeks and 5 days ago

(executable base64 encodeD header)

Comment by rodolfoap 120 weeks and 5 days ago

head -1 F shows the exact same as yours, then the next part

root@sorry:/home/chris# read O;mount -o loop,offset=$O F /mnt;

mount: invalid offset '' specified

Comment by chrismccoy 120 weeks and 4 days ago

nm got it working ;)

Comment by chrismccoy 120 weeks and 4 days ago

Your point of view

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