Difference between revisions of "FAQ/Howto"
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==== Create the script to mount the drive ==== | ==== Create the script to mount the drive ==== | ||
| − | + | <pre> | |
| − | + | #/usr/local/bin/auto-mount/auto-mount.sh | |
| + | #!/bin/bash | ||
| − | + | cryptsetup luksOpen --key-file /etc/keys/GaOS-Home.key /dev/usb/sandisk HomeGaOS | |
| − | + | if [[ ! -e /mnt/HomeGaOS ]]; then | |
| − | + | mkdir /mnt/HomeGaOS | |
| − | + | fi | |
| − | + | if [[ -e /dev/mapper/HomeGaOS ]]; then | |
| − | + | mount /dev/mapper/HomeGaOS /mnt/HomeGaOS | |
| − | + | else | |
| − | + | echo "not ready" | |
| − | + | fi | |
| + | </pre> | ||
==== Move the /home folders to the flashdrive and create symlinks ==== | ==== Move the /home folders to the flashdrive and create symlinks ==== | ||
Revision as of 00:17, 21 June 2017
Some frequently useful configuration options:
Contents
Expand your Home to a flash drive
It is not recommended to mount your /home to an external USB Flash Drive because if you loose it you gonna be in trouble. However you can move your /home folders to an external place and free some storage.
With the solution below, when you connect the flashdrive it gonna unlock and automount it to /mnt/HomeGaOS; Also, if you boot with the flashdrive pluged in it gonna be ready and available before you login in, so you can access it remotely, at least its the expected behavior.
Encrypt your flash drive
Flash drives are easy to loose. If you don't want anyone looking around your data, you should encrypt your flash drive. I will not detail this part, as data encryption are complex and you have better and complete information at https://wiki.archlinux.org/index.php/Dm-crypt/Encrypting_an_entire_system
Step 1: Encrypt the entire flash drive:
$ sudo cryptsetup -v -c aes-xts-plain64 -s 512 -h sha512 --use-random luksFormat /dev/sdX
You should change /dev/sdX for your flashdrive/sdcard. Be carefully, this may lead to data damage.
Step 2: Open the encrypted content:
$ sudo cryptsetup luksOpen /dev/sdX HomeGaOS
This you map your unlock device to /dev/mapper/HomeGaOS
Step 3: Create the file system:
$ sudo mkfs.ext4 /dev/mapper/HomeGaOS
Source: https://wiki.archlinux.org/index.php/Dm-crypt/Device_encryption#Encryption_options_for_LUKS_mode
Add an encryption key to the flashdrive
To automatically mount the flash drive without having to type the password we gonna create an encryption key and add it to the flash drive
Step 1: Generate the key
$ sudo dd if=/dev/urandom of=/etc/keys/GaOS-Home.key bs=1024 count=4
I'm assuming the keyfile gonna be stored at /etc/keys folder. This will create a file with random content with the size of 4096 bits. You can use any file to act as keyfile. A 4kb file with random content is good enough.
Step 2: Make the keyfile read-only to root:
$ sudo chmod 0400 /root/keyfile
Alternatively you can chown your keyfile to root:root and move it into the /root folder or other place.
Step 3: Add the keyfile to LUKS
$ sudo cryptsetup luksAddKey /dev/sdX /etc/keys/keyfile
Source: https://www.howtoforge.com/automatically-unlock-luks-encrypted-drives-with-a-keyfile
Create udev rules
## /etc/udev/rules.d/10-usbdrive.rules
KERNEL=="sd*", ATTRS{serial}=="4C530001300414107405", ATTRS{idVendor}=="0781", ATTRS{idProduct}=="5590", SYMLINK+="usb/sandisk", ENV{SYSTEMD_WANTS}="auto-mount-flash-drive.service"
You can get the values for serial, idVendor, and idProduct with dmesg output; type before inserting USB drive:
$ dmesg -w
Sources: (a) https://paste.ubuntu.com/24558174/ (b) http://jasonwryan.com/blog/2014/01/20/udev/
Create systemd service
#/etc/systemd/system/auto-mount-flash-drive.service [Unit] Description=Auto mount encryted flash drive [Service] ExecStart=/usr/local/bin/auto-mount/auto-mount.sh
Create the script to mount the drive
#/usr/local/bin/auto-mount/auto-mount.sh #!/bin/bash cryptsetup luksOpen --key-file /etc/keys/GaOS-Home.key /dev/usb/sandisk HomeGaOS if [[ ! -e /mnt/HomeGaOS ]]; then mkdir /mnt/HomeGaOS fi if [[ -e /dev/mapper/HomeGaOS ]]; then mount /dev/mapper/HomeGaOS /mnt/HomeGaOS else echo "not ready" fi
Move the /home folders to the flashdrive and create symlinks
Now you can move your folders from /home/user to /mnt/HomeGaOS and create a symlink to it. For example:
$ mv /home/user/Downloads /mnt/HomeGaOS $ ln -s /mnt/HomeGaOS/Downloads /home/user/Downloads
If you login without the flashdrive the symlinks gonna be broken but whenever you connect the flashdrive they become available.
Please, help to improve this.
Problems: still need to think a solution for unmount. If you need to fast suspend and remove the flashdrive, when you back from suspend maybe you need to umount, lock luks manually, before insert the flashdrive again. I don't know the risks for data loose on this.
