< Features
m (Add virt category) |
(Update status, libvirt bits in F19 now) |
||
| (8 intermediate revisions by 2 users not shown) | |||
| Line 12: | Line 12: | ||
== Current status == | == Current status == | ||
* Targeted release: [[Releases/19 | Fedora 19]] | * Targeted release: [[Releases/19 | Fedora 19]] | ||
* Last updated: | * Last updated: 2013-03-12 | ||
* Percentage of completion: | * Percentage of completion: 90% | ||
== Detailed Description == | == Detailed Description == | ||
The linux kernel collects entropy from various non-deterministic hardware events, like mouse and keyboard input, and network traffic. This entropy is then exposed through /dev/random, commonly used by cryptographic applications that need true randomness to maintain security. However if more entropy is being consumed than is being produced, we have entropy starvation: reading from /dev/random will block, which can cause a denial of service. A common example here is use of /dev/random by SSL in various services. | The linux kernel collects entropy from various non-deterministic hardware events, like mouse and keyboard input, and network traffic. This entropy is then exposed through /dev/random, commonly used by cryptographic applications that need true randomness to maintain security. However if more entropy is being consumed than is being produced, we have entropy starvation: reading from /dev/random will block, which can cause a denial of service. A common example here is use of /dev/random by SSL in various services. | ||
VirtIO RNG (random number generator) is a paravirtualized device that is exposed as a hardware RNG device to the guest. Virtio RNG just appears as a regular hardware RNG to the guest, which the kernel reads from to fill its entropy pool. This effectively allows a host to entropy into a guest via several means: The default mode uses the host's /dev/random, but a physical HW RNG device or EGD (Entropy Gathering Daemon) can also be used. | VirtIO RNG (random number generator) is a paravirtualized device that is exposed as a hardware RNG device to the guest. Virtio RNG just appears as a regular hardware RNG to the guest, which the kernel reads from to fill its entropy pool. This effectively allows a host to inject entropy into a guest via several means: The default mode uses the host's /dev/random, but a physical HW RNG device or EGD (Entropy Gathering Daemon) source can also be used. | ||
== Benefit to Fedora == | == Benefit to Fedora == | ||
Makes Fedora a better platform for hosting server VMs. | |||
== Scope == | == Scope == | ||
* Virtio RNG driver in kernel (DONE, since 2.6.26) | * Virtio RNG driver in kernel (DONE, since 2.6.26) | ||
* QEMU Device (DONE, since qemu 1.3) | * QEMU Device (DONE, since qemu 1.3) | ||
* Libvirt support ( | * Libvirt support (DONE, in 1.0.3) | ||
* Apps (all optional but would be nice if they are done) | * Apps (all optional but would be nice if they are done) | ||
** virt-install (Not done) | ** virt-install (Not done) | ||
| Line 33: | Line 33: | ||
== How To Test == | == How To Test == | ||
TBD | TBD | ||
XXX: Manual qemu bits at http://wiki.qemu.org/Features/VirtIORNG#Testing | XXX: Manual qemu bits at http://wiki.qemu.org/Features/VirtIORNG#Testing | ||
XXX: Libvirt instructions based on posted patches | XXX: Libvirt instructions based on posted patches | ||
== User Experience == | == User Experience == | ||
Server VMs will have more options for avoiding entropy starvation. | |||
== Dependencies == | == Dependencies == | ||
| Line 51: | Line 53: | ||
* [https://www.redhat.com/archives/libvir-list/2012-December/msg00937.html Libvirt RFC detailing potential future RNG daemon] | * [https://www.redhat.com/archives/libvir-list/2012-December/msg00937.html Libvirt RFC detailing potential future RNG daemon] | ||
* [http://egd.sourceforge.net/ Entropy gathering daemon (EGD)] | * [http://egd.sourceforge.net/ Entropy gathering daemon (EGD)] | ||
* [http://log.amitshah.net/2013/01/about-random-numbers-and-virtual-machines/ Amit's post about virt and RNG] | |||
* [https://lwn.net/Articles/525459/ LWN article about random numbers] | |||
== Release Notes == | == Release Notes == | ||
| Line 56: | Line 60: | ||
== Comments and Discussion == | == Comments and Discussion == | ||
* fedora devel discussion about the feature: https://lists.fedoraproject.org/pipermail/devel/2013-February/177867.html | |||
[[Category: | [[Category:FeatureAcceptedF19]] | ||
[[Category:Virtualization]] | [[Category:Virtualization]] | ||
Revision as of 14:12, 12 March 2013
Virtio RNG
Summary
Provide a paravirtual random number generator to virtual machines, to prevent entropy starvation in guests.
Owner
- Name: Cole Robinson
- Email: crobinso@redhat.com
- Name: Amit Shah
- Email: amit.shah@redhat.com
Current status
- Targeted release: Fedora 19
- Last updated: 2013-03-12
- Percentage of completion: 90%
Detailed Description
The linux kernel collects entropy from various non-deterministic hardware events, like mouse and keyboard input, and network traffic. This entropy is then exposed through /dev/random, commonly used by cryptographic applications that need true randomness to maintain security. However if more entropy is being consumed than is being produced, we have entropy starvation: reading from /dev/random will block, which can cause a denial of service. A common example here is use of /dev/random by SSL in various services.
VirtIO RNG (random number generator) is a paravirtualized device that is exposed as a hardware RNG device to the guest. Virtio RNG just appears as a regular hardware RNG to the guest, which the kernel reads from to fill its entropy pool. This effectively allows a host to inject entropy into a guest via several means: The default mode uses the host's /dev/random, but a physical HW RNG device or EGD (Entropy Gathering Daemon) source can also be used.
Benefit to Fedora
Makes Fedora a better platform for hosting server VMs.
Scope
- Virtio RNG driver in kernel (DONE, since 2.6.26)
- QEMU Device (DONE, since qemu 1.3)
- Libvirt support (DONE, in 1.0.3)
- Apps (all optional but would be nice if they are done)
- virt-install (Not done)
- virt-manager (Not done)
How To Test
TBD
XXX: Manual qemu bits at http://wiki.qemu.org/Features/VirtIORNG#Testing
XXX: Libvirt instructions based on posted patches
User Experience
Server VMs will have more options for avoiding entropy starvation.
Dependencies
None.
Contingency Plan
Since this is brand new functionality, if it isn't ready in time, nothing has changed. We just drop this feature page.
Documentation
- QEMU VirtIO RNG feature page
- QEMU patch email from May 2012
- Latest libvirt patch posting
- Libvirt RFC detailing potential future RNG daemon
- Entropy gathering daemon (EGD)
- Amit's post about virt and RNG
- LWN article about random numbers
Release Notes
KVM and libvirt now support a paravirtual random number generator device. This can be used to prevent entropy starvation in virtual machines.
Comments and Discussion
- fedora devel discussion about the feature: https://lists.fedoraproject.org/pipermail/devel/2013-February/177867.html