Kicksecure Tuning

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Making Kicksecure Faster. Tuning Kicksecure.

Choose your virtualizer to get started.

VirtualBox

Virtualizer VirtualBox has been chosen.

KVM

Virtualizer KVM has been chosen.

See below.

Introduction[edit]

Info Everything in this chapter is entirely optional.

Applying steps in this chapter can improve Kicksecure performance, but often at the cost of reduced security or an increased fingerprinting risk. Earlier entries in this chapter are easier to apply, while later tuning entries require a greater skill level.

Tested Tuning Steps[edit]

Hardware-accelerated Graphics[edit]

VirtualBox

Warning: This procedure lessens security.

To enable hardware-accelerated graphics for Kicksecure, perform these steps on the host:

  1. Power off the VM.
  2. VirtualBox → click a VM → Settings → Display → Graphics Controller → Acceleration: check Enable 3D Acceleration → OK
  3. Restart the VM.

Also refer to the VirtualBox manual: Hardware-Accelerated Graphicsarchive.org.

Forum discussion: VirtualBox 3D Accelerationarchive.org

KVM

Undocumented.

Renderer[edit]

softwarecontext renderer is set by default in Kicksecure. This is accomplished by setting the environment variable QMLSCENE_DEVICE=softwarecontext . This setting is particularly useful in cases where hardware acceleration is disabled, which is the default setting in Kicksecure VMs, for applications such as:

  • Monero
  • signal-desktop, and potentially
  • wire-desktop, as well as
  • other electron-based applications. (Note: This setting is unrelated to electrum.)

However, this configuration has been reported to cause issues with:

General information:

  • Does this setting have any security impact? No.
  • When does it make sense to undo this setting? Likely, when Hardware-accelerated Graphics is enabled.
  • Is the user encouraged to experiment with this setting? Yes.

How to test if issues are caused by QMLSCENE_DEVICE=softwarecontext?

Option A): Command line method.

1. Temporarily unset the environment variable.

unset QMLSCENE_DEVICE

2. Launch the application from the command line.

3. Done.

Notes:

  • This method does not work if:
    • Applications are started from the start menu.
    • The unset command has not been run previously in different terminal emulator tabs.
  • This process needs to be repeated after a reboot.

Option B): Configuration file deletion method.

1. Delete the configuration file that sets this environment variable.

sudo rm -f /etc/profile.d/20_software_rendering_in_vms.sh

2. Reboot the system.

sudo reboot

3. Done.

4. To undo this change (optional, see footnote). [1]

Forum search: QMLSCENE_DEVICEarchive.org

Additional information for developers only:

Increase Virtual Machine RAM[edit]

VirtualBox

RAM available to Virtual Machines can be increased via VirtualBox settings.

To check how much RAM is free, use free -m in a Terminal. Consider the example below:

  1. Shutdown the VM.
  2. Assign more RAM: Virtual machine → Menu → Settings → Adjust Memory slider to 4096 → Hit: OK
  3. Restart the VM.

See also: Advice for Systems with Low RAM.

KVM

Undocumented.

Additional CPU Cores[edit]

VirtualBox

Warning: this procedure may increase fingerprinting risks.

On systems with multi-core processors, if minor identifiers are not of any concern [2] then the number of cores available to the Virtual Machine(s) can be increased in VirtualBox settings.

Do not use the maximum since that could lead to system instability! Always leave at least one CPU unassigned; for example, if you have four CPUs then assign a maximum of three CPUs to the VM. [3]

  1. Power off the VM.
  2. VirtualBox → click a VM → Settings → System → Processor → Reduce to 3 → OK
  3. Restart the VM.

KVM

Undocumented.

Untested Tuning Steps[edit]

Disable CPU Mitigations[edit]

Warning: this procedure lessens security.

Untested!

Consider disabling the Spectre Meltdown mitigations. (Related forum discussionarchive.org.)

This step should be performed in the VM intended for disabled CPU mitigations and on the host operating system if either Kicksecure or security-misc are in use.

1. Remove the relevant CPU mitigations file.

sudo rm /etc/default/grub.d/40_cpu_mitigations.cfg

2. Update grub.

sudo update-grub

3. Reboot.

4. Done.

Nested Paging and VPIDs[edit]

VirtualBox

It is possible to increase performance by using largepages and/or Virtual Processor Identifiers (VPIDs). It is unknown if this decreases security or stability. For further information refer to the VirtualBox manual: Nested Paging and VPIDsarchive.org.

vboxmanage modifyvm Kicksecure-Xfce --largepages on

vboxmanage modifyvm Kicksecure-Xfce --largepages on

vboxmanage modifyvm Kicksecure-Xfce --vtxvpid on

vboxmanage modifyvm Kicksecure-Xfce --vtxvpid on

KVM

Undocumented.

Memory Ballooning, Page Fusion and Memory Overcommitment[edit]

Warning: this procedure lessens security.

Memory ballooning worsens security because it is a vector for side channel attacks on memory; see here for further information. [4]

For other security considerations, refer to the VirtualBox manual: Memory Overcommitmentarchive.org.

Undocumented Tuning Settings[edit]

There are probably more tuning-related settings, but these are currently undocumented at Kicksecure. Interested readers can review the manual for relevant settings of their respective virtualizer, which are unlikely to be bundled under a "tuning" chapter.

VirtualBox

To view all settings, run.

vboxmanage showvminfo Kicksecure-Xfce

Next, learn about all of these settings by reviewing the VirtualBox manualarchive.org.

KVM

Undocumented.

PCI Passthrough[edit]

Warning: this procedure lessens security.

This setting can improve graphics performance dramatically, but it worsens security because VMs should not have direct access to physical hardware.

In simple terms, this feature allows the direct use of physical PCI devices on the host by the guest even if the host does not have drivers for the particular device.

VirtualBox

For further information, refer to VirtualBox Manual: PCI Passthrougharchive.org.

KVM

Undocumented.

See Also[edit]

Footnotes[edit]

  1. ↑ sudo apt-get-reset vm-config-dist (Refer to Reset Configuration Files to Vendor Default for more information.)
  2. ↑ Adding CPU cores is considered a minor risk.
  3. ↑ VirtualBox ticket: VirtualBox should now prohibit assigning all physical CPUs to a VM and/or fix VirtualBox CPU assignment manualarchive.org.
  4. ↑ This entry relates to KVM but the research similarly applies to other virtualizers unless they have implemented and documented specific protections.

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