Posts Tagged ‘Virtualbox Virtual Machine’

CentOS disable SELinux permanently or one time on grub Linux kernel boot time

Saturday, July 24th, 2021

selinux-artistic-penguin-logo-protect-data

 

1. Office 365 cloud connected computer and a VirtualBox hosted machine with SELINUX preventing it to boot

At my job we're in process of migrating my old Lenovo Laptop Thinkpad model L560 Laptop to Dell Latitude 5510 wiith Intel Core i5 vPro CPU and 256 Gb SSD Hard Drive.  The new laptops are generally fiine though they're not even a middle class computers and generally I prefer thinkpads. The sad thing out of this is our employee decided to migrate to Office 365 (again perhaps another stupid managerial decision out of an excel sheet wtih a balance to save some money … 

As you can imagine Office 365 is not really PCI Standards compliant and not secure since our data is stored in Microsoft cloud and theoretically Microsoft has and owns our data or could wipe loose the data if they want to. The other obvious security downside I've noticed with the new "Secure PCI complaint laptop" is the initial PC login screen which by default offers fingerprint authentication or the even worse  and even less secure face recognition, but obviosly everyhing becomes more and more crazy and people become less and less cautious for security if that would save money or centralize the data … In the name of security we completely waste security that is very dubious paradox I don't really understand but anyways, enough rant back to the main topic of this article is how to and I had to disable selinux?

As part of Migration I've used Microsoft OneDrive to copy old files from the Thinkpad to the Latitude (as on the old machine USB's are forbidden and I cannot copy over wiith a siimple USB driive, as well as II have no right to open the laptop and copy data from the Hard driive, and even if we had this right without breaking up some crazy company policy that will not be possible as the hard drive data on old laptop is encrypted, the funny thing is that the new laptop data comes encrypted and there is no something out of the box as BitDefender or McAffee incryption (once again, obviously our data security is a victim of some managarial decisions) …
 

2. OneDrive copy problems unable to sync some of the copied files to Onedrive


Anyways as the Old Laptop's security is quite paranoid and we're like Fort Nox, only port 80 and port 443 connections to the internet can be initiated to get around this harsh restrictions it was as simple to use a Virtualbox Virtual Machine. So on old laptop I've installed a CentOS 7 image which I used so far and I used one drive to copy my vbox .vdi image on the new laptop work machine.

The first head buml was the .vdi which seems to be prohibited to be copied to OneDrive, so to work around this I had to rename the origianl CentOS7.vdi to CentOS7.vdi-renamed on old laptop and once the data is in one drive copy my Vitualbox VM/ directory from one drive to the Dell Latitude machine and rename the .vdi-named towards .vdi as well as import it from the latest installed VirtualBox on the new machine.
 

3. Disable SELINUX from initial grub boot


So far so good but as usual happens with miigrations I've struck towards another blocker, the VM image once initiated to boot from Virtualbox badly crashed with some complains that selinux cannot be loaded.
Realizing CentOS 7 has the more or less meaningless Selinux, I've took the opportunity to disable SeLinux.

To do so I've booted the Kernel with Selinux disabled from GRUB2 loader prompt before Kernel and OS Userland boots.

 

 

I thought I need to type the information on the source in grub. What I did is very simple, on the Linux GRUB boot screen I've pressed

'e' keyboard letter

that brought the grub boot loader into edit mode.

Then I had to add selinux=0 on the edited selected kernel version, as shown in below screenshot:

selinux-disable-from-grub.png

Next to boot the Linux VM without Selinux enabled one time,  just had to press together

Ctrl+X then add selinux=0 on the edited selected kernel version, that should be added as shown in the screenshot somewhere after the line of
root=/dev/mapper/….

4. Permanently Disable Selinux on CentOS 7


Once I managed to boot Virtual Machine properly with Oracle Virtualbox, to permanently disabled selinux I had to:

 

Once booted into CentOS, to check the status of selinux run:

 

# sestatus
Copy
SELinux status:                 enabled
SELinuxfs mount:                /sys/fs/selinux
SELinux root directory:         /etc/selinux
Loaded policy name:             targeted
Current mode:                   enforcing
Mode from config file:          enforcing
Policy MLS status:              enabled
Policy deny_unknown status:     allowed
Max kernel policy version:      31

 

5. Disable SELinux one time with setenforce command


You can temporarily change the SELinux mode from targeted to permissive with the following command:

 

# setenforce 0


Next o permanently disable SELinux on your CentOS 7 next time the system boots, Open the /etc/selinux/config file and set the SELINUX mod parameter to disabled.

On CentOS 7 you can  edit the kernel parameters in /etc/default/grub (in the GRUB_CMDLINE_LINUX= key) and set selinux=0 so on next VM / PC boot we boot with a SELINUX disabled for example add   RUB_CMDLINE_LINUX=selinux=0 to the file then you have to regenerate your Grub config like this:
 

# grub2-mkconfig -o /etc/grub2.cfg
# grub2-mkconfig -o /etc/grub2-efi.cfg


Further on to disable SeLinux on OS level edit /etc/selinux
 

Default /etc/selinux/config with selinux enabled should look like so:

# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
#       enforcing – SELinux security policy is enforced.
#       permissive – SELinux prints warnings instead of enforcing.
#       disabled – No SELinux policy is loaded.
SELINUX=enforcing
# SELINUXTYPE= can take one of these two values:
#       targeted – Targeted processes are protected,
#       mls – Multi Level Security protection.
SELINUXTYPE=targeted


To disable SeLinux modify the file to be something like:

# This file controls the state of SELinux on the system.
# SELINUX= can take one of these three values:
#       enforcing – SELinux security policy is enforced.
#       permissive – SELinux prints warnings instead of enforcing.
#       disabled – No SELinux policy is loaded.
SELINUX=disabled
# SELINUXTYPE= can take one of these two values:
#       targeted – Targeted processes are protected,
#       mls – Multi Level Security protection.
SELINUXTYPE=targeted

6. Check SELINUX status is disabled

# sestatus

SELinux status:                 disabled

So in this article shottly was explained shortly the fake security adopted by using Microsoft Cloud environment Offiice 365, my faced OneDrive copy issues (which prevented even my old laptop Virtual Machine to boot properly and the handy trick to rename the file that is unwilling to get copied from old PC towards m$ OneDrive as well as the grub trick to disable Selinux permanently from grub2.

How to Increase virtualbox Linux install machine VM .VDI hard disk size to free space on root partition – Move /usr to a new partition

Tuesday, October 10th, 2017

extend-vdi-virtual-machine-partition-with-virtualbox-howto-virtualbox-logo
 

How to Increse Hard Disk size of VirtualBox Virtual Machine .VDI file to Free Space on root Partition or Howto move /usr large partition to separate new partition?


I just wondered how to increase hard disk size of Virtualbox Virtual Machine image .VDI, because for some stupid reason I've created my initial hard disk size for Linux partition to be the default 10 Gigabytes.

The problem is the packages I need to have installed on the Virtual Machine which will be a testbed for future tests of a production website applications are taking up too much space, once installed so I'm left with no space
in /var/lib/mysql for the database import. So what can I do in that case is to simply free up disk space or Merge ROOT partition with another partition.

Since merging the partition is not a trivial job and would require me to have installable CD with the Linux distro (in my case that's Debian Linux) or have a bootable USB flash drive, I preferred second approach to problem e.g. to free up disk space on ROOT partition by creating a second partition and move the /usr folder to reside there.

Before that it is of course necessery to  have extended the .VDI file using VirtualBox, so more space than the default 10GB preconfigured are available, this is easily done on Windows OS as, VBox is provided with GUI clickable option to do it, but for who knows what reason that is not the case with Linux, so Linux users only option to increase VDI file is to manually run command part of the virtualbox package, that is not a hard task really but it requires some typing and basic knowledge on how to run commands in terminal.


To .VDI resize (extend), we first go to default location where VirtualBox stores its image .VDI files (by default as of moment of writting this article – this is ~/"VrtualBox VMs"  (or home directory of logged in user dir VirtualBox VMs), the command to use is VBoxManage

 

root@jericho:/home/hipo# cd VirtualBox VMs/
root@jericho:/home/hipo/VirtualBox VMs# ls
Debian 6  Debian 9  Windows 10
root@jericho:/home/hipo/VirtualBox VMs# cd Debian 6/
r
oot@jericho:/home/hipo/VirtualBox VMs/Debian 6# ls
Debian 6.vbox  Debian 6.vbox-prev  Debian 6.vdi  Logs  NewVirtualDisk1.vdi  Snapshots

root@jericho:/home/hipo/VirtualBox VMs/Debian 6# VBoxManage modifyhd Debian 6.vdi –resize 20000
0%…10%…20%…30%…40%…50%…60%…70%…80%…90%…100%
root@jericho:/home/hipo/VirtualBox VMs/Debian 6#


 

Above command does resize the 10GB default created partition for Linux, where I have installed Linux which was 99% full of data, because of the many packages I installed to 20GB size, to make it bigger just use the respective size, be it 30000 (for 30GB) or 100000 (for 100GB) etc.

Even though in this example VBoxManage virtual partition resize command was done for GNU / Linux Operating System, it can be done for any other Operating as well to resize the size of the Virtual .VDI file (Virtual Machine) partition, be it Windows 7 / 8 / 10 or the rest of Free Operating systems FreeBSD / OpenBSD / BSD that are installed in a VM etc.

Next Launch the Virtual Machine with VBox Server client Program and install there Gparted (GNU Parted), as we'll need it to create a new Hard Disk Partition:

 

$ VirtualBox

 


Inside virtualmachine's in gnome-terminal / xterm etc. depending on the graphical environment used do install with apt-get:

 

debian:# apt-get install –yes gparted

 

debian~:# gparted


Notice that gparted has to be ran as a root superuser.

 

Run GParted and create new EXT3 filesystem that is 10GB (the size of the new created partition).

If you have installed Debian to place all partitions under / (root directory /dev/sda1) then the fresh new partition to create should be
/dev/sda3, anyways just look closely in EXT3 and in your case if the partiition is named differently create according to proper partition /dev/ naming.

I'll not run into details on how to create the partition with GParted as the program interface is very self-explanatory, the only thing is to apply the update to create partition and the ext3 filesystem, that's being done
with a green tick:

gparted-create-ext3-partition-howto-linux

Next step is to check with fdisk whether, we have ext3 properly created  filesystem as we've done already with GPARTED:

Once we have the partition created with EXT3 filesystem, we're ready to move /usr temporary to other folder, I use usually /root for the move but you can create anywhere a new folder for that and move to there.

To move to /root directory run again in terminal:

 

debian:~# mv /usr /root
debian:~# mkdir /usr

 

howto-extend-root-filesystem-disk-space-linux-move-usr-folder-to-root-temporary-debian-gnu-linux

 

Note that during the move operations, your Desktop icons will become without (with broken) pictures and the default Debian background picture is to disappear, that's because the GUI environment will soon realize /usr/ libraries that're periodically reloaded in memory are missing and will be unable to reload them as it does in a cycle.

That should take a few minutes, so grab a coffee or if you're a smoker (hope not as smoking kills 🙂 ), in 5 / 10 minutes time depending on your computer / server configuration, it will be over, so we're ready to create new /usr dir and mount the  new partition:

 

debian:~# mount /dev/sda3 /usr

 

howto-extend-root-filesystem-disk-space-linux-move-usr-folder-to-root-temporary-debian-gnu-linux1

 

Now we check with mount command whether mount is fine:

 

check-if-filesystem-is-properly-mounted-linux-debian-screenshot


Now  /dev/sda3 is mounted under /usr  and we have to move back /root/usr directory content back to the newly mounted /usr so we run command:
 

debian:~#  mv /root/usr/* /usr/*


Finally we need to create proper records for the new partition inside /etc/fstab (fstab –FileSystem Tab file – the file which describes instructs the Linux OS what partition to boot where, what)

HOW TO CHECK LINUX UUID FOR A PARTITION??

Before adding anything to /etc/fstab you need to check the UUID of /dev/sda3 (or whatever the partition is called), without proper UUID, the system might fail to boot.
So here is how to check the UUID we'll need for config:

 

hipo@debian:~$ /sbin/blkid /dev/sda3
/dev/sda3: UUID="2273db4b-3069-4f78-90fc-e7483c0305bd" SEC_TYPE="ext2" TYPE="ext3"

hipo@debian:~$ ls -al /dev/disk/by-uuid/
total 0
drwxr-xr-x 2 root root 100 Oct  6 05:16 .
drwxr-xr-x 6 root root 120 Oct  6 05:16 ..
lrwxrwxrwx 1 root root  10 Oct  6 05:16 2273db4b-3069-4f78-90fc-e7483c0305bd -> ../../sda3
lrwxrwxrwx 1 root root  10 Oct  6 05:16 b98d92cd-41aa-4e18-a474-9b8df445dbe5 -> ../../sda1
lrwxrwxrwx 1 root root  10 Oct  6 05:16 f27f7448-f200-4983-b54f-b9e5206f77ac -> ../../sda5

As you can see our /dev/sda3 UUID is 2273db4b-3069-4f78-90fc-e7483c0305bd

Further on lets view and edit /etc/fstab you can also download a copy of my Virtual Machine fstab here

 

debian:~# cat /etc/fstab

# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
proc            /proc           proc    defaults        0       0
# / was on /dev/sda1 during installation
UUID=b98d92cd-41aa-4e18-a474-9b8df445dbe5 /               ext3    errors=remount-ro 0       1
# swap was on /dev/sda5 during installation
UUID=f27f7448-f200-4983-b54f-b9e5206f77ac none            swap    sw              0       0
/dev/scd0       /media/cdrom0   udf,iso9660 user,noauto     0       0
/dev/scd1       /media/cdrom1   udf,iso9660 user,noauto     0       0


We need to add following line to  /etc/fstab:
 

UUID=2273db4b-3069-4f78-90fc-e7483c0305bd    /usr        ext3 error=remount-ro    0    1

 


Open the file with your favourite text editor (gedit / nano / pico / vim / joe) etc.

debian:~# vim /etc/fstab

 

# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point>   <type>  <options>       <dump>  <pass>
proc            /proc           proc    defaults        0       0
# / was on /dev/sda1 during installation
UUID=b98d92cd-41aa-4e18-a474-9b8df445dbe5 /               ext3    errors=remount-ro 0       1
# swap was on /dev/sda5 during installation
UUID=f27f7448-f200-4983-b54f-b9e5206f77ac none            swap    sw              0       0
/dev/scd0       /media/cdrom0   udf,iso9660 user,noauto     0       0
/dev/scd1       /media/cdrom1   udf,iso9660 user,noauto     0       0

UUID=2273db4b-3069-4f78-90fc-e7483c0305bd     /usr        ext3 error=remount-ro    0    1    

Basicly it should be possible to add (for historic reasons) also instead of UUID=2273db4b-3069-4f78-90fc-e7483c0305bd  /dev/sda3
So it looks like so but, the better practice is to use UUID line given.

Well that's all folks now /usr directory will contain all your heavy root partition (disk filling) libraries and files, so you can happily use /var/lib/mysql or /var/lib/postgresql /var/www to store your web application files and import your databases.

Big thanks to Ubuntu Forums article – How do I increase the hard disk size of the Virtual Machine article for inspiring this post.

Hope that helps anyone and thanks and other comments are always welcome ! 🙂