One of the Big Things coming soon, in Qubes 4.1, is the first public version of the GUI domain: the next step in decoupling the graphical hardware, the display and management, and the host system. Very briefly, the GUI domain is a qube separate from dom0 that handles all the display-related tasks and some system management.
Why make a GUI domain at all?
One of the biggest security concerns at the moment for Qubes is how much power is in dom0. Once a person has access to it, they can do anything: and while we separate it quite effectively from what is running inside application qubes, dom0 is still a big, bloated and complex domain that performs many disparate functions. It handles managing other domains, display and graphical interfaces, multiple devices (including audio devices), memory and disk management, and so on.
We mitigate many of the GUI-related risks (like the powers wielded by the window manager, or the fact that huge, complex libraries such as Qt/Gtk are always an increased attack surface) through compartmentalization: Applications in VMs can’t talk to GUI toolkits in dom0 other than through a very limited Qubes-GUI protocol, and GUI toolkits in application VMs can’t talk directly to dom0’s X server. Moreover, dom0 is responsible for drawing the colored window borders the represent trust levels, so compromised VMs can’t spoof them.
Nonetheless, having a GUI in dom0 at all is, at best, a source of many dangerous temptations. It’s far too easy to use it to access untrusted (and thus potentially dangerous data), for example by mounting a disk from a qube into dom0. Even browsing relaxing landscapes as desktop wallpapers can expose dom0 to numerous vulnerabilities that intermittently appear in image-processing libraries.
Furthermore, while in theory dom0 is isolated from the outside world, some graphical devices (e.g. displays connected via HDMI or DVI) offer two-way communication, which threatens this isolation and makes it harder to maintain. If a malicious device (rather than the user’s trusted monitor) were to be connected to one of these ports, it could inject data that could be processed inside of dom0. As long as graphical devices are in dom0, they also cannot be safely proxied to other domains. This is because the various solutions to multiplexing access to the GPU at the GPU/driver level (which would expose the “full” GPU to a VM) are orders of magnitude more complex than running display drivers in just one place. We consider this added complexity too risky to put it in dom0. Errors in the drivers could expose dom0 to an attack, and attacks on dom0 are the biggest threat to the Qubes security model.
The current model, in which the GUI and administrative domains are both within dom0, is also problematic from a management point of view. The way existing user-based privilege control works in most modern systems is one of the reasons why we need Qubes at all: It provides far too little separation, and root exploits seem to be inescapable in a system as monolithic as Linux. Separating the GUI domain from dom0 allows us to manage its access to the underlying system.
This has obvious uses in an organizational context, allowing for (possibly remotely) managed Qubes installations, but even in a personal computer context it is often extremely useful to have multiple user accounts with truly separate permissions and privileges. Perhaps you would like to create a guest account for any friend who needs to borrow your computer for a moment, and allow that account to create Disposable VMs, but not to create normal qubes and not to access other users’ qubes. It becomes possible when the GUI domain is decoupled from dom0. All kinds of kiosk modes, providing safer environments for less-technical users who prefer to be sure they cannot break something accidentally, multi-user environments — they all become possible.
What needs to be ready?
Why make a GUI domain at all?
One of the biggest security concerns at the moment for Qubes is how much power is in dom0. Once a person has access to it, they can do anything: and while we separate it quite effectively from what is running inside application qubes, dom0 is still a big, bloated and complex domain that performs many disparate functions. It handles managing other domains, display and graphical interfaces, multiple devices (including audio devices), memory and disk management, and so on.
We mitigate many of the GUI-related risks (like the powers wielded by the window manager, or the fact that huge, complex libraries such as Qt/Gtk are always an increased attack surface) through compartmentalization: Applications in VMs can’t talk to GUI toolkits in dom0 other than through a very limited Qubes-GUI protocol, and GUI toolkits in application VMs can’t talk directly to dom0’s X server. Moreover, dom0 is responsible for drawing the colored window borders the represent trust levels, so compromised VMs can’t spoof them.
Nonetheless, having a GUI in dom0 at all is, at best, a source of many dangerous temptations. It’s far too easy to use it to access untrusted (and thus potentially dangerous data), for example by mounting a disk from a qube into dom0. Even browsing relaxing landscapes as desktop wallpapers can expose dom0 to numerous vulnerabilities that intermittently appear in image-processing libraries.
Furthermore, while in theory dom0 is isolated from the outside world, some graphical devices (e.g. displays connected via HDMI or DVI) offer two-way communication, which threatens this isolation and makes it harder to maintain. If a malicious device (rather than the user’s trusted monitor) were to be connected to one of these ports, it could inject data that could be processed inside of dom0. As long as graphical devices are in dom0, they also cannot be safely proxied to other domains. This is because the various solutions to multiplexing access to the GPU at the GPU/driver level (which would expose the “full” GPU to a VM) are orders of magnitude more complex than running display drivers in just one place. We consider this added complexity too risky to put it in dom0. Errors in the drivers could expose dom0 to an attack, and attacks on dom0 are the biggest threat to the Qubes security model.
The current model, in which the GUI and administrative domains are both within dom0, is also problematic from a management point of view. The way existing user-based privilege control works in most modern systems is one of the reasons why we need Qubes at all: It provides far too little separation, and root exploits seem to be inescapable in a system as monolithic as Linux. Separating the GUI domain from dom0 allows us to manage its access to the underlying system.
This has obvious uses in an organizational context, allowing for (possibly remotely) managed Qubes installations, but even in a personal computer context it is often extremely useful to have multiple user accounts with truly separate permissions and privileges. Perhaps you would like to create a guest account for any friend who needs to borrow your computer for a moment, and allow that account to create Disposable VMs, but not to create normal qubes and not to access other users’ qubes. It becomes possible when the GUI domain is decoupled from dom0. All kinds of kiosk modes, providing safer environments for less-technical users who prefer to be sure they cannot break something accidentally, multi-user environments — they all become possible.
What needs to be ready?
There were two big issues in the previous Qubes architecture that needed to be handled for an effective approach to a GUI domain: how the GUI protocol relied on dom0-level privileges and how managing anything in the system required dom0-level access to the hypervisor.
GUI Protocol
Detailed documentation of the current GUI protocol is available here (https://www.qubes-os.org/doc/gui/). In brief, it consists of a GUI agent and a GUI daemon. The GUI agent runs in a qube and connects to the GUI daemon in dom0, passing a list of memory addresses of window buffers. As the GUI daemon is running in dom0, with privileged access to, well, everything, it can just map any page of any qube’s memory. You can see why this might be a bit worrying: Access to memory is power, thus dom0 is all-powerful. It would be far worse if we tried to duplicate this architecture and make our GUI domain a qube with the same memory-related privileges. It would just result in two dom0s. Rather than being reduced, the attack surface would be increased.
The upcoming 4.1 release changes this protocol to a more flexible form. It will no longer use direct memory addresses, but an abstract mechanism in which the qube has to explicitly allow access to a particular memory page. In our current implementation — under Xen — we use the grant tables mechanism, which provides a separate memory allocation API and allows working on grants and not directly on memory pages. Other implementations will also be possible: whether for another hypervisor (e.g. KVM) or for a completely different architecture not based on shared memory (e.g. directly sending frames to another machine).
Managing the system
The second problem — system management — is actually partially solved already in Qubes 4.0. Administrative actions such as creating, changing or starting qubes can be handled via qrexec calls and controlled via qrexec policy. You can read more about the Admin API, one of the big changes in Qubes 4.0 that made all this possible here (https://www.qubes-os.org/news/2017/06/27/qubes-admin-api/).
Currently, in Qubes 4.0, dom0 handles all these administrative actions. However, in order to avoid unpleasant surprises and to prepare the architecture for the GUI domain, we already always perform them via Admin API. At the design level, dom0 is no longer a special and different case: It makes qrexec calls like any other qube.
There’s an interesting, subtle detail here: We just accepted dom0 being able to run anything in any way inside other qubes. But if we want to implement a more contained and less-privileged GUI domain, it would defeat part of its purpose to just permit it to run any sort of qvm-run do-what-I-want in any of the managed qubes. Qubes 4.0 introduces a special qubes.StartApp qrexec service that runs only applications defined inside the target qube (currently defined via .desktop files in Linux and .lnk files in Windows, placed in predetermined directories). This mechanism allows a qube to explicitly define “what the GUI domain can execute inside me,” and not just hand over all the power to the managing domain. This also makes it possible to define allowed applications using the qrexec policy!
Other issues
Actually implementing a GUI domain (more details below) revealed a lot of minor problems that require some handling. Unsurprisingly, it turns out a modern operating system encourages a very close relationship between whatever part of it deals with graphical display and all the rest of the hardware.
Power management has numerous vital graphical tools that need some kind of access to underlying hardware. From a battery level widget to laptop power management settings, those innocuous GUI tools would like to have a surprisingly broad access to the system itself. Even suspend and shutdown need special handling. In Qubes 4.0, we could just turn off dom0 and know the rest of the system would follow, but it is no longer so simple with a non-privileged GUI domain in the
GUI Protocol
Detailed documentation of the current GUI protocol is available here (https://www.qubes-os.org/doc/gui/). In brief, it consists of a GUI agent and a GUI daemon. The GUI agent runs in a qube and connects to the GUI daemon in dom0, passing a list of memory addresses of window buffers. As the GUI daemon is running in dom0, with privileged access to, well, everything, it can just map any page of any qube’s memory. You can see why this might be a bit worrying: Access to memory is power, thus dom0 is all-powerful. It would be far worse if we tried to duplicate this architecture and make our GUI domain a qube with the same memory-related privileges. It would just result in two dom0s. Rather than being reduced, the attack surface would be increased.
The upcoming 4.1 release changes this protocol to a more flexible form. It will no longer use direct memory addresses, but an abstract mechanism in which the qube has to explicitly allow access to a particular memory page. In our current implementation — under Xen — we use the grant tables mechanism, which provides a separate memory allocation API and allows working on grants and not directly on memory pages. Other implementations will also be possible: whether for another hypervisor (e.g. KVM) or for a completely different architecture not based on shared memory (e.g. directly sending frames to another machine).
Managing the system
The second problem — system management — is actually partially solved already in Qubes 4.0. Administrative actions such as creating, changing or starting qubes can be handled via qrexec calls and controlled via qrexec policy. You can read more about the Admin API, one of the big changes in Qubes 4.0 that made all this possible here (https://www.qubes-os.org/news/2017/06/27/qubes-admin-api/).
Currently, in Qubes 4.0, dom0 handles all these administrative actions. However, in order to avoid unpleasant surprises and to prepare the architecture for the GUI domain, we already always perform them via Admin API. At the design level, dom0 is no longer a special and different case: It makes qrexec calls like any other qube.
There’s an interesting, subtle detail here: We just accepted dom0 being able to run anything in any way inside other qubes. But if we want to implement a more contained and less-privileged GUI domain, it would defeat part of its purpose to just permit it to run any sort of qvm-run do-what-I-want in any of the managed qubes. Qubes 4.0 introduces a special qubes.StartApp qrexec service that runs only applications defined inside the target qube (currently defined via .desktop files in Linux and .lnk files in Windows, placed in predetermined directories). This mechanism allows a qube to explicitly define “what the GUI domain can execute inside me,” and not just hand over all the power to the managing domain. This also makes it possible to define allowed applications using the qrexec policy!
Other issues
Actually implementing a GUI domain (more details below) revealed a lot of minor problems that require some handling. Unsurprisingly, it turns out a modern operating system encourages a very close relationship between whatever part of it deals with graphical display and all the rest of the hardware.
Power management has numerous vital graphical tools that need some kind of access to underlying hardware. From a battery level widget to laptop power management settings, those innocuous GUI tools would like to have a surprisingly broad access to the system itself. Even suspend and shutdown need special handling. In Qubes 4.0, we could just turn off dom0 and know the rest of the system would follow, but it is no longer so simple with a non-privileged GUI domain in the
picture.
Keyboard and user input need to be carefully proxied to the GUI domain to enable us to actually use the system. The existing InputProxy system needs to be expanded to ferry information from the USB domain (in the case of USB keyboards and mice) and from dom0 (in some other cases, like PS/2 keyboards) to the GUI domain.
The current state of those minor (minor in comparison to broad, architecture-level changes, but by no means unimportant) issues is tracked here (https://github.com/QubesOS/qubes-issues/issues/4186).
How can the GUI domain actually work?
GPU passthrough: the perfect-world desktop solution
Keyboard and user input need to be carefully proxied to the GUI domain to enable us to actually use the system. The existing InputProxy system needs to be expanded to ferry information from the USB domain (in the case of USB keyboards and mice) and from dom0 (in some other cases, like PS/2 keyboards) to the GUI domain.
The current state of those minor (minor in comparison to broad, architecture-level changes, but by no means unimportant) issues is tracked here (https://github.com/QubesOS/qubes-issues/issues/4186).
How can the GUI domain actually work?
GPU passthrough: the perfect-world desktop solution
In the perfect world, we could simply connect the graphics card to the VM as a PCI device and enjoy a new, more comfortable level of separation. Unfortunately, the world of computer hardware is very far from a perfect one. This solution works only very rarely. For most graphics cards, it just fails, although some success has been observed on some AMD cards. Even if, in theory, the architecture supports GPU passthrough, many implementations rely on various hardware quirks and peculiarities absent when there is no direct access to the underlying system. For example, the video BIOS (the code that the GPU provides to the system to initialize itself) in many cases assumes that it is running with full privileges and tries to access various registers and memory areas not available to (or virtualized in) VMs.
And all that is without even approaching issues with multiple graphical cards, multiple outputs or suspending the host; or the fact that some hardware manufactures (like NVIDIA) attempt to block GPU passthrough for some of their products.
At the moment, a group of very brave university students are working on the basic GPU passthrough case as their bachelor’s degree project. We wish them a lot of luck in this difficult endeavor!
Virtual server: the perfect remote solution
And all that is without even approaching issues with multiple graphical cards, multiple outputs or suspending the host; or the fact that some hardware manufactures (like NVIDIA) attempt to block GPU passthrough for some of their products.
At the moment, a group of very brave university students are working on the basic GPU passthrough case as their bachelor’s degree project. We wish them a lot of luck in this difficult endeavor!
Virtual server: the perfect remote solution
Instead of wrestling with the hardware problems, GUI domain could instead connect to a virtual graphical server such as FreeRDP or VNC. This server could be accessible from anywhere on the network (in practice, it should be secured with at least a VPN, as bugs allowing unauthorized users access could be very dangerous), allowing for a Qubes Server hosting many separate sets of qubes used by different users, still maintaining comfortable separation between the qubes and the users. Qrexec policy allows the administrator to comfortably manage this solution: Every GUI domain can have its own set of privileges, managed qubes, Disposable VM permissions etc.
Surprisingly, a virtual server solution does actually work with the current state of Qubes as of the 4.1 developer preview build, and it allows us to bypass the dreaded GPU passthrough complications. The only not-so-small problem is that it does not actually handle our main use case: Qubes running locally on a single machine. This is because it uses the network to expose the GUI, and the place where the local display is handled (dom0) doesn’t have access to the network.
The compromise solution
Surprisingly, a virtual server solution does actually work with the current state of Qubes as of the 4.1 developer preview build, and it allows us to bypass the dreaded GPU passthrough complications. The only not-so-small problem is that it does not actually handle our main use case: Qubes running locally on a single machine. This is because it uses the network to expose the GUI, and the place where the local display is handled (dom0) doesn’t have access to the network.
The compromise solution
While GPU passthrough is a work-in-progress and a server-based solution is impractical, there is a compromise solution: Dom0 can keep the X Server and graphics drivers but use them to run only a single, simple application — a full-screen proxy for the GUI domain’s graphical server (an approach similar to the one used by OpenXT). We could even use VNC for this, but luckily, there is another solution based on protocols that have already been tested and implemented. Through the GUI protocol’s shared memory and a Xephyr server on the dom0 side, we can achieve something of a GUI protocol nesting.
Like many compromises, it is far from completely satisfying. The biggest problem is that it still keeps clutter (in the form of drivers and X Server) in dom0 — much less clutter given that huge libraries and desktop environments no longer need to live there, but still clutter. Many of the GPU passthrough problems are still here: Power management will require some finesse, and multi-monitor setups are still untested. (They may require us to extend some of Xephyr’s functionality.)
However, we can be pretty sure there will never be a GPU passthrough solution that works on every system. It is not just about the complexity of the problem and the multitude of GPU products available. As mentioned above, some manufacturers intentionally obstruct GPU passthrough in their graphics cards, so it is likely that some hardware configurations will never have full support. This is why the compromise solution will be available as a fallback even once more robust GPU passthrough is developed.
Surprise dependency: audio
As far as system architecture goes, audio systems are a completely separate set of processes, communication channels and tools — but this is only the theory. In practice, audio is very tightly connected to GUI in most modern systems. On Qubes 4.0, pulseaudio tools start together with GUI tools both in dom0 and in application qubes.
While audio drivers and tools are not nearly as bloated and sprawling as GUI tools, keeping them in dom0 is still suboptimal, and with the move toward a GUI domain, it will become increasingly impossible. Our first step was to see how we could move audio away from dom0: Connect it together with the GPU to the GUI domain and see what breaks. Surprisingly, few things did, and while some hard-coded “connect to dom0 for all of your audio needs” configurations needed to be updated, those changes are already done in Qubes 4.1.
This is not the final solution we would like, though; it would be best to truly decouple audio and GUI, creating a dedicated and separate audio aomain.
Audio Domain
The audio domain will be a separate virtual machine that accesses and proxies audio card access. This way, we can not only remove audio from dom0 (making it smaller and less exposed) but also from the GUI domain (which, by virtue of being still quite privileged, should also have as little additional capabilities as possible).
All the complex audio subsystems, from pulseaudio (which controls volume for each domain) to audio mixers and microphones, would reside in the audio domain. It will have its own set of particular privileges. For example, due to the current audio hardware architecture, the audio domain will have access to the complete audio intput and output, but isolating them in a separate domain will significantly reduce the attack surface. Keeping audio in the same domain as the keyboard or screen could, in theory, lead to eavesdropping attacks. In a separate audio domain, all those potentially vulnerable devices are isolated. Even Bluetooth audio devices (like headphones) could finally be used securely, without exposing the whole system to attack.
What will actually be in Qubes 4.1
Most of code to handle the compromise solution is either already merged into the Qubes master branch or currently awaits final merging and will be available in Qubes 4.1. However, it will not be the default.
Like many compromises, it is far from completely satisfying. The biggest problem is that it still keeps clutter (in the form of drivers and X Server) in dom0 — much less clutter given that huge libraries and desktop environments no longer need to live there, but still clutter. Many of the GPU passthrough problems are still here: Power management will require some finesse, and multi-monitor setups are still untested. (They may require us to extend some of Xephyr’s functionality.)
However, we can be pretty sure there will never be a GPU passthrough solution that works on every system. It is not just about the complexity of the problem and the multitude of GPU products available. As mentioned above, some manufacturers intentionally obstruct GPU passthrough in their graphics cards, so it is likely that some hardware configurations will never have full support. This is why the compromise solution will be available as a fallback even once more robust GPU passthrough is developed.
Surprise dependency: audio
As far as system architecture goes, audio systems are a completely separate set of processes, communication channels and tools — but this is only the theory. In practice, audio is very tightly connected to GUI in most modern systems. On Qubes 4.0, pulseaudio tools start together with GUI tools both in dom0 and in application qubes.
While audio drivers and tools are not nearly as bloated and sprawling as GUI tools, keeping them in dom0 is still suboptimal, and with the move toward a GUI domain, it will become increasingly impossible. Our first step was to see how we could move audio away from dom0: Connect it together with the GPU to the GUI domain and see what breaks. Surprisingly, few things did, and while some hard-coded “connect to dom0 for all of your audio needs” configurations needed to be updated, those changes are already done in Qubes 4.1.
This is not the final solution we would like, though; it would be best to truly decouple audio and GUI, creating a dedicated and separate audio aomain.
Audio Domain
The audio domain will be a separate virtual machine that accesses and proxies audio card access. This way, we can not only remove audio from dom0 (making it smaller and less exposed) but also from the GUI domain (which, by virtue of being still quite privileged, should also have as little additional capabilities as possible).
All the complex audio subsystems, from pulseaudio (which controls volume for each domain) to audio mixers and microphones, would reside in the audio domain. It will have its own set of particular privileges. For example, due to the current audio hardware architecture, the audio domain will have access to the complete audio intput and output, but isolating them in a separate domain will significantly reduce the attack surface. Keeping audio in the same domain as the keyboard or screen could, in theory, lead to eavesdropping attacks. In a separate audio domain, all those potentially vulnerable devices are isolated. Even Bluetooth audio devices (like headphones) could finally be used securely, without exposing the whole system to attack.
What will actually be in Qubes 4.1
Most of code to handle the compromise solution is either already merged into the Qubes master branch or currently awaits final merging and will be available in Qubes 4.1. However, it will not be the default.
The GUI domain will be an experimental feature. We will provide a salt formula to easily configure it for anyone who wants to try it out and play around with it. Our main goal is to test everything we can test without GPU passthrough in order to reach a state in which the aforementioned more minor problems are handled. Then we’ll be ready for a GPU passthrough solution once it is developed (which is being worked on separately).
The GUI domain is currently ready for Linux-based qubes and for fullscreen HVMs, not for the Windows GUI agent. At the moment, nobody on our team is the sort of Windows wizard who could do that, so Qubes 4.1 will not have GUI domain support for for the Windows GUI agent. (Coincidentally, this is the same reason that the GUI agent is not compatible with Windows 10 at the moment. If you, dear reader, would like to work with us on Windows 10 GUI agent and GUI domain support, please let us know!)
Currently, many parts of the Qubes architecture assume a singular target GUI domain (or audio domain) for every qube. There may be multiple GUI domains in the system, but each qube can only use one of them. We do not plan to change this in the foreseeable future.
Plans for the future
Introducing the GUI domain opens up a lot of interesting new possibilities. First and foremost, even in the middle-of-the-road, painful-compromise solution, dom0 will still be much, much smaller (no desktop managers or huge graphical libraries), thus it can be much more easily ported to another distribution.
A smaller dom0 could also be placed completely in RAM, making the whole disk controller and storage subsystem independent from it and possibly isolated in its own storage domain, as described in the Qubes Architecture Specification (https://www.qubes-os.org/attachment/wiki/QubesArchitecture/arch-spec-0.3.pdf) only 10 years ago. Now we’re finally moving closer to this goal!
Finally, decoupling support for VNC and other remote desktop capabilities opens the door to various server-based solutions in which Qubes can run on a remote server, and we can delegate some or all of our domains to other machines (potentially with faster harder and more resources). This is a another step toward Qubes Air (https://www.qubes-os.org/news/2018/01/22/qubes-air/).
The GUI domain is currently ready for Linux-based qubes and for fullscreen HVMs, not for the Windows GUI agent. At the moment, nobody on our team is the sort of Windows wizard who could do that, so Qubes 4.1 will not have GUI domain support for for the Windows GUI agent. (Coincidentally, this is the same reason that the GUI agent is not compatible with Windows 10 at the moment. If you, dear reader, would like to work with us on Windows 10 GUI agent and GUI domain support, please let us know!)
Currently, many parts of the Qubes architecture assume a singular target GUI domain (or audio domain) for every qube. There may be multiple GUI domains in the system, but each qube can only use one of them. We do not plan to change this in the foreseeable future.
Plans for the future
Introducing the GUI domain opens up a lot of interesting new possibilities. First and foremost, even in the middle-of-the-road, painful-compromise solution, dom0 will still be much, much smaller (no desktop managers or huge graphical libraries), thus it can be much more easily ported to another distribution.
A smaller dom0 could also be placed completely in RAM, making the whole disk controller and storage subsystem independent from it and possibly isolated in its own storage domain, as described in the Qubes Architecture Specification (https://www.qubes-os.org/attachment/wiki/QubesArchitecture/arch-spec-0.3.pdf) only 10 years ago. Now we’re finally moving closer to this goal!
Finally, decoupling support for VNC and other remote desktop capabilities opens the door to various server-based solutions in which Qubes can run on a remote server, and we can delegate some or all of our domains to other machines (potentially with faster harder and more resources). This is a another step toward Qubes Air (https://www.qubes-os.org/news/2018/01/22/qubes-air/).
XenProject Developer and Design Summit: Update in light of COVID-19
https://xenproject.org/2020/03/26/xenproject-developer-and-design-summit-update-in-light-of-covid-19/
The past several weeks have been an uncertain time globally. In the spirit of transparency, I wanted to update our community on plans for our annual developer conference, The Xen...
https://xenproject.org/2020/03/26/xenproject-developer-and-design-summit-update-in-light-of-covid-19/
The past several weeks have been an uncertain time globally. In the spirit of transparency, I wanted to update our community on plans for our annual developer conference, The Xen...
Qubes Canary #23
https://www.qubes-os.org/news/2020/04/15/canary-23/
We have published Qubes Canary #23. The text of this canary is
reproduced below. This canary and its accompanying signatures will
always be available in the Qubes Security Pack (qubes-secpack).
View Qubes Canary #23 in the qubes-secpack:
https://github.com/QubesOS/qubes-secpack/blob/master/canaries/canary-023-2020.txt
Learn about the qubes-secpack, including how to obtain, verify, and read
it:
https://www.qubes-os.org/security/pack/
View all past canaries:
https://www.qubes-os.org/security/canaries/
---===[ Qubes Canary #23 ]===---
Statements
-----------
The Qubes core developers who have digitally signed this file [1]
state the following:
1. The date of issue of this canary is April 9, 2020.
2. There have been 56 Qubes Security Bulletins published so far.
3. The Qubes Master Signing Key fingerprint is:
427F 11FD 0FAA 4B08 0123 F01C DDFA 1A3E 3687 9494
4. No warrants have ever been served to us with regard to the Qubes OS
Project (e.g. to hand out the private signing keys or to introduce
backdoors).
5. We plan to publish the next of these canary statements in the first
two weeks of September 2020. Special note should be taken if no new canary
is published by that time or if the list of statements changes without
plausible explanation.
Special announcements
----------------------
None.
Disclaimers and notes
----------------------
We would like to remind you that Qubes OS has been designed under the
assumption that all relevant infrastructure is permanently
compromised. This means that we assume NO trust in any of the servers
or services which host or provide any Qubes-related data, in
particular, software updates, source code repositories, and Qubes ISO
downloads.
This canary scheme is not infallible. Although signing the declaration
makes it very difficult for a third party to produce arbitrary
declarations, it does not prevent them from using force or other
means, like blackmail or compromising the signers' laptops, to coerce
us to produce false declarations.
The news feeds quoted below (Proof of freshness) serves to demonstrate
that this canary could not have been created prior to the date stated.
It shows that a series of canaries was not created in advance.
This declaration is merely a best effort and is provided without any
guarantee or warranty. It is not legally binding in any way to
anybody. None of the signers should be ever held legally responsible
for any of the statements made here.
Proof of freshness
-------------------
Thu, 09 Apr 2020 01:16:49 +0000
Source: DER SPIEGEL - International (https://www.spiegel.de/international/index.rss)
Politicians Call for Fewer Climate Protections During Coronavirus Crisis
Coronavirus: En refusant les eurobonds, l’Allemagne fait preuve d’égoïsme, d’obstination et de lâcheté
Coronavirus: El rechazo alemán de los eurobonos es insolidario, mezquino y cobarde
New York City: Eight Days in the New Capital of Corona
Coronavirus: Il rifiuto tedesco degli Eurobond è non solidale, gretto e vigliacco
Source: NYT > World News (https://rss.nytimes.com/services/xml/rss/nyt/World.xml)
Saudi Arabia, Hit by Coronavirus, Declares Cease-Fire in Yemen: Live Updates
Saudi Arabia Declares Cease-Fire in Yemen, Citing Fears of Coronavirus
Eight U.K. Doctors Died From Coronavirus. All Were Immigrants.
Some of Europe, ‘Walking a Tightrope,’ Will Loosen Coronavirus Restrictions
China’s Coronavirus Battle Is Waning. Its Propaganda Fight Is Not.
Source: BBC News - World (https://feeds.bbci.co.uk/news/world/rss.xml)
Coronavirus: WHO chief urges end to 'politicisation' of virus
Bernie Sanders suspends presidential campaign
Yemen: Saudi-led coalition announces ceasefire
Woman who revealed Clinton-Lewinsky scandal dies
Coronavirus: How Russia's ballet wasn't shut down despite lockdown
Source: Reuters: World News (http://feeds.reuters.com/reuters/worldnews)
https://www.qubes-os.org/news/2020/04/15/canary-23/
We have published Qubes Canary #23. The text of this canary is
reproduced below. This canary and its accompanying signatures will
always be available in the Qubes Security Pack (qubes-secpack).
View Qubes Canary #23 in the qubes-secpack:
https://github.com/QubesOS/qubes-secpack/blob/master/canaries/canary-023-2020.txt
Learn about the qubes-secpack, including how to obtain, verify, and read
it:
https://www.qubes-os.org/security/pack/
View all past canaries:
https://www.qubes-os.org/security/canaries/
---===[ Qubes Canary #23 ]===---
Statements
-----------
The Qubes core developers who have digitally signed this file [1]
state the following:
1. The date of issue of this canary is April 9, 2020.
2. There have been 56 Qubes Security Bulletins published so far.
3. The Qubes Master Signing Key fingerprint is:
427F 11FD 0FAA 4B08 0123 F01C DDFA 1A3E 3687 9494
4. No warrants have ever been served to us with regard to the Qubes OS
Project (e.g. to hand out the private signing keys or to introduce
backdoors).
5. We plan to publish the next of these canary statements in the first
two weeks of September 2020. Special note should be taken if no new canary
is published by that time or if the list of statements changes without
plausible explanation.
Special announcements
----------------------
None.
Disclaimers and notes
----------------------
We would like to remind you that Qubes OS has been designed under the
assumption that all relevant infrastructure is permanently
compromised. This means that we assume NO trust in any of the servers
or services which host or provide any Qubes-related data, in
particular, software updates, source code repositories, and Qubes ISO
downloads.
This canary scheme is not infallible. Although signing the declaration
makes it very difficult for a third party to produce arbitrary
declarations, it does not prevent them from using force or other
means, like blackmail or compromising the signers' laptops, to coerce
us to produce false declarations.
The news feeds quoted below (Proof of freshness) serves to demonstrate
that this canary could not have been created prior to the date stated.
It shows that a series of canaries was not created in advance.
This declaration is merely a best effort and is provided without any
guarantee or warranty. It is not legally binding in any way to
anybody. None of the signers should be ever held legally responsible
for any of the statements made here.
Proof of freshness
-------------------
Thu, 09 Apr 2020 01:16:49 +0000
Source: DER SPIEGEL - International (https://www.spiegel.de/international/index.rss)
Politicians Call for Fewer Climate Protections During Coronavirus Crisis
Coronavirus: En refusant les eurobonds, l’Allemagne fait preuve d’égoïsme, d’obstination et de lâcheté
Coronavirus: El rechazo alemán de los eurobonos es insolidario, mezquino y cobarde
New York City: Eight Days in the New Capital of Corona
Coronavirus: Il rifiuto tedesco degli Eurobond è non solidale, gretto e vigliacco
Source: NYT > World News (https://rss.nytimes.com/services/xml/rss/nyt/World.xml)
Saudi Arabia, Hit by Coronavirus, Declares Cease-Fire in Yemen: Live Updates
Saudi Arabia Declares Cease-Fire in Yemen, Citing Fears of Coronavirus
Eight U.K. Doctors Died From Coronavirus. All Were Immigrants.
Some of Europe, ‘Walking a Tightrope,’ Will Loosen Coronavirus Restrictions
China’s Coronavirus Battle Is Waning. Its Propaganda Fight Is Not.
Source: BBC News - World (https://feeds.bbci.co.uk/news/world/rss.xml)
Coronavirus: WHO chief urges end to 'politicisation' of virus
Bernie Sanders suspends presidential campaign
Yemen: Saudi-led coalition announces ceasefire
Woman who revealed Clinton-Lewinsky scandal dies
Coronavirus: How Russia's ballet wasn't shut down despite lockdown
Source: Reuters: World News (http://feeds.reuters.com/reuters/worldnews)
WHO head defends handling of coronavirus pandemic against Trump criticism
Brazil turns to local industry to build ventilators as China orders fall through
Ecuador's Moreno calls for probe into handling of corpses in coronavirus outbreak
Australian police take 'black box' off cruise ship in coronavirus homicide probe
Mexico registers 3,181 cases of coronavirus and 174 deaths
Source: Blockchain.info
0000000000000000000d88e12aee57e8aa90ceea6b74b962a39427c5f2fdb6d0
Footnotes
----------
[1] This file should be signed in two ways: (1) via detached PGP
signatures by each of the signers, distributed together with this
canary in the qubes-secpack.git repo, and (2) via digital signatures
on the corresponding qubes-secpack.git repo tags. [2]
[2] Don't just trust the contents of this file blindly! Verify the
digital signatures!
Brazil turns to local industry to build ventilators as China orders fall through
Ecuador's Moreno calls for probe into handling of corpses in coronavirus outbreak
Australian police take 'black box' off cruise ship in coronavirus homicide probe
Mexico registers 3,181 cases of coronavirus and 174 deaths
Source: Blockchain.info
0000000000000000000d88e12aee57e8aa90ceea6b74b962a39427c5f2fdb6d0
Footnotes
----------
[1] This file should be signed in two ways: (1) via detached PGP
signatures by each of the signers, distributed together with this
canary in the qubes-secpack.git repo, and (2) via digital signatures
on the corresponding qubes-secpack.git repo tags. [2]
[2] Don't just trust the contents of this file blindly! Verify the
digital signatures!
XSAs 313, 314, 316, and 318 do not affect the security of Qubes OS
https://www.qubes-os.org/news/2020/04/15/xsa-313-314-316-318-qubes-not-affected/
The Xen Project has published Xen Security Advisories 313, 314, 316,
and 318 (XSA-313, XSA-314, XSA-316, and XSA-318, respectively). These
XSAs do not affect the security of Qubes OS, and no user action is
necessary.
These XSAs have been added to the XSA Tracker (https://www.qubes-os.org/security/xsa/):
https://www.qubes-os.org/security/xsa/#313
https://www.qubes-os.org/security/xsa/#314
https://www.qubes-os.org/security/xsa/#316
https://www.qubes-os.org/security/xsa/#318
https://www.qubes-os.org/news/2020/04/15/xsa-313-314-316-318-qubes-not-affected/
The Xen Project has published Xen Security Advisories 313, 314, 316,
and 318 (XSA-313, XSA-314, XSA-316, and XSA-318, respectively). These
XSAs do not affect the security of Qubes OS, and no user action is
necessary.
These XSAs have been added to the XSA Tracker (https://www.qubes-os.org/security/xsa/):
https://www.qubes-os.org/security/xsa/#313
https://www.qubes-os.org/security/xsa/#314
https://www.qubes-os.org/security/xsa/#316
https://www.qubes-os.org/security/xsa/#318
If you haven’t yet, Join our wonderful (Unofficial) Support group!
https://news.1rj.ru/str/joinchat/B8FHpkEToMfgdREGV7wzRQ
https://news.1rj.ru/str/joinchat/B8FHpkEToMfgdREGV7wzRQ
Telegram
QubesOS Chat
(Community Support)
Alternative community instead of online forum and discord.
@QubesOS
>No spam/ads/NSFW/shit posts/spam bots
>Respect others
>Stay on topic
>Be transparent
If you need help ask!
Rules are enforced with ban or restrictions.
Alternative community instead of online forum and discord.
@QubesOS
>No spam/ads/NSFW/shit posts/spam bots
>Respect others
>Stay on topic
>Be transparent
If you need help ask!
Rules are enforced with ban or restrictions.
Fedora 30 approaching EOL, Fedora 31 TemplateVM available, Fedora 32 TemplateVM in testing
https://www.qubes-os.org/news/2020/04/30/fedora-31-template-available/
This announcement includes several updates regarding Fedora TemplateVMs.
Fedora 30 approaching EOL
With the release of Fedora 32 on April 28, Fedora 30 is expected to
reach EOL (end-of-life (https://fedoraproject.org/wiki/End_of_life)) on May 26, 2020.
Fedora 31 TemplateVM available
A new Fedora 31 TemplateVM is now available for both Qubes 4.0 and 4.1.
Instructions are available for upgrading Fedora TemplateVMs (https://www.qubes-os.org/doc/template/fedora/upgrade/). We also
provide a fresh Fedora 31 TemplateVM package through the official Qubes
repositories, which you can get with the following commands (in dom0).
Standard (https://www.qubes-os.org/doc/templates/fedora/) Fedora 31 TemplateVM:
$ sudo qubes-dom0-update qubes-template-fedora-31
Minimal (https://www.qubes-os.org/doc/templates/minimal/) Fedora 31 TemplateVM:
$ sudo qubes-dom0-update qubes-template-fedora-31-minimal
After upgrading to a Fedora 31 TemplateVM, please remember to switch all
qubes that were using the old template to use the new one (https://www.qubes-os.org/doc/templates/#switching).
Fedora 32 TemplateVM in testing
For advanced users, a new Fedora 32 TemplateVM is currently available in
the qubes-templates-itl-testing repository for both Qubes 4.0 and 4.1.
We would greatly appreciate testing and feedback (https://www.qubes-os.org/doc/testing/#providing-feedback) from the community
regarding this template.
https://www.qubes-os.org/news/2020/04/30/fedora-31-template-available/
This announcement includes several updates regarding Fedora TemplateVMs.
Fedora 30 approaching EOL
With the release of Fedora 32 on April 28, Fedora 30 is expected to
reach EOL (end-of-life (https://fedoraproject.org/wiki/End_of_life)) on May 26, 2020.
Fedora 31 TemplateVM available
A new Fedora 31 TemplateVM is now available for both Qubes 4.0 and 4.1.
Instructions are available for upgrading Fedora TemplateVMs (https://www.qubes-os.org/doc/template/fedora/upgrade/). We also
provide a fresh Fedora 31 TemplateVM package through the official Qubes
repositories, which you can get with the following commands (in dom0).
Standard (https://www.qubes-os.org/doc/templates/fedora/) Fedora 31 TemplateVM:
$ sudo qubes-dom0-update qubes-template-fedora-31
Minimal (https://www.qubes-os.org/doc/templates/minimal/) Fedora 31 TemplateVM:
$ sudo qubes-dom0-update qubes-template-fedora-31-minimal
After upgrading to a Fedora 31 TemplateVM, please remember to switch all
qubes that were using the old template to use the new one (https://www.qubes-os.org/doc/templates/#switching).
Fedora 32 TemplateVM in testing
For advanced users, a new Fedora 32 TemplateVM is currently available in
the qubes-templates-itl-testing repository for both Qubes 4.0 and 4.1.
We would greatly appreciate testing and feedback (https://www.qubes-os.org/doc/testing/#providing-feedback) from the community
regarding this template.
Xen Summit 2020 Pivots to a Virtual Experience
https://xenproject.org/2020/05/19/xen-summit-2020-pivots-to-a-virtual-experience/
In light of continued Covid-19 safety concerns, the 2020 XenProject Developer and Design Summit will now be held virtually on July 6-9. As our in-person event shifts to a virtual...
https://xenproject.org/2020/05/19/xen-summit-2020-pivots-to-a-virtual-experience/
In light of continued Covid-19 safety concerns, the 2020 XenProject Developer and Design Summit will now be held virtually on July 6-9. As our in-person event shifts to a virtual...
Qubes awarded MOSS Mission Partners grant!
https://www.qubes-os.org/news/2020/05/22/moss-mission-partners-grant/
We’re proud to announce that the Qubes OS Project has been awarded a
Mozilla Open Source Support (MOSS) (https://www.mozilla.org/en-US/moss/) awards program grant in the amount
of 128,000 USD. This generous one-year grant will fund the work of
Frédéric Pierret (https://www.qubes-os.org/team/#fr%C3%A9d%C3%A9ric-pierret) on making Qubes more robust and stable, as well as
several key parts of Nina Alter (https://www.qubes-os.org/team/#nina-eleanor-alter)’s extensive work on making Qubes more
user-friendly.
There are three separate tracks for MOSS awards. Qubes has been awarded
a grant in the Mission Partners (https://www.mozilla.org/en-US/moss/mission-partners/) track. As Mozilla explains, “The
Mission Partners track supports open source projects that significantly
advance Mozilla’s mission.” It is a great honor for Qubes to be
recognized as such a project, and we’re thrilled by the important work
that this grant will enable.
https://www.qubes-os.org/news/2020/05/22/moss-mission-partners-grant/
We’re proud to announce that the Qubes OS Project has been awarded a
Mozilla Open Source Support (MOSS) (https://www.mozilla.org/en-US/moss/) awards program grant in the amount
of 128,000 USD. This generous one-year grant will fund the work of
Frédéric Pierret (https://www.qubes-os.org/team/#fr%C3%A9d%C3%A9ric-pierret) on making Qubes more robust and stable, as well as
several key parts of Nina Alter (https://www.qubes-os.org/team/#nina-eleanor-alter)’s extensive work on making Qubes more
user-friendly.
There are three separate tracks for MOSS awards. Qubes has been awarded
a grant in the Mission Partners (https://www.mozilla.org/en-US/moss/mission-partners/) track. As Mozilla explains, “The
Mission Partners track supports open source projects that significantly
advance Mozilla’s mission.” It is a great honor for Qubes to be
recognized as such a project, and we’re thrilled by the important work
that this grant will enable.
Google Summer of Code & Season of Docs 2020
https://www.qubes-os.org/news/2020/05/23/google-summer-of-code-and-season-of-docs-2020/
We’re pleased to announce that the Qubes OS Project will be
participating in both Google Summer of Code (https://summerofcode.withgoogle.com/) and Google Season of
Docs (https://developers.google.com/season-of-docs) for 2020!
For Google Summer of Code this year, William Huang will be working on
Template Manager and Package Handling Improvements (https://summerofcode.withgoogle.com/projects/#6190965460566016) under the
mentorship of Qubes project lead Marek Marczykowski-Górecki (https://www.qubes-os.org/team/#marek-marczykowski-g%C3%B3recki).
Specifically, William will be “designing a better mechanism for handling
template installation and creating a user-facing application to deal
with such mechanism and other template-related configuration,
consolidating the management of templates.” For more information about
Google Summer of Code in relation to the Qubes OS project, please see
our information page (https://www.qubes-os.org/gsoc/).
Meanwhile, with Google Season of Docs, we’re still in the technical
writer exploration phase (https://developers.google.com/season-of-docs/docs/timeline), in which “interested technical writers
discuss project ideas with mentoring organizations.” If you’re
interested in participating in Google Season of Docs with Qubes (https://www.qubes-os.org/gsod/),
the technical writer application period begins on June 9, 2020 at 18:00
UTC, and the deadline is July 9, 2020 at 18:00 UTC.
https://www.qubes-os.org/news/2020/05/23/google-summer-of-code-and-season-of-docs-2020/
We’re pleased to announce that the Qubes OS Project will be
participating in both Google Summer of Code (https://summerofcode.withgoogle.com/) and Google Season of
Docs (https://developers.google.com/season-of-docs) for 2020!
For Google Summer of Code this year, William Huang will be working on
Template Manager and Package Handling Improvements (https://summerofcode.withgoogle.com/projects/#6190965460566016) under the
mentorship of Qubes project lead Marek Marczykowski-Górecki (https://www.qubes-os.org/team/#marek-marczykowski-g%C3%B3recki).
Specifically, William will be “designing a better mechanism for handling
template installation and creating a user-facing application to deal
with such mechanism and other template-related configuration,
consolidating the management of templates.” For more information about
Google Summer of Code in relation to the Qubes OS project, please see
our information page (https://www.qubes-os.org/gsoc/).
Meanwhile, with Google Season of Docs, we’re still in the technical
writer exploration phase (https://developers.google.com/season-of-docs/docs/timeline), in which “interested technical writers
discuss project ideas with mentoring organizations.” If you’re
interested in participating in Google Season of Docs with Qubes (https://www.qubes-os.org/gsod/),
the technical writer application period begins on June 9, 2020 at 18:00
UTC, and the deadline is July 9, 2020 at 18:00 UTC.
QSB #057: Special Register Buffer speculative side channel (XSA-320)
https://www.qubes-os.org/news/2020/06/11/qsb-057/
We have just published Qubes Security Bulletin (QSB) #057:
Special Register Buffer speculative side channel (XSA-320).
The text of this QSB is reproduced below. This QSB and its accompanying
signatures will always be available in the Qubes Security Pack (qubes-secpack).
View QSB #057 in the qubes-secpack:
https://github.com/QubesOS/qubes-secpack/blob/master/QSBs/qsb-057-2020.txt
Learn about the qubes-secpack, including how to obtain, verify, and read it:
https://www.qubes-os.org/security/pack/
View all past QSBs:
https://www.qubes-os.org/security/bulletins/
View XSA-320 in the XSA Tracker:
https://www.qubes-os.org/security/xsa/#320
---===[ Qubes Security Bulletin #57 ]===---
2020-06-11
Special Register Buffer speculative side channel (XSA-320)
Summary
========
On 2020-06-09, the Xen Security Team published Xen Security Advisory
320 (CVE-2020-0543 / XSA-320) [1] with the following denoscription:
| This issue is related to the MDS and TAA vulnerabilities. Please see
| https://xenbits.xen.org/xsa/advisory-297.html (MDS) and
| https://xenbits.xen.org/xsa/advisory-305.html (TAA) for details.
|
| Certain processor operations microarchitecturally need to read data
| from outside the physical core (e.g. to communicate with the random
| number generator). In some implementations, this operation is called
| a Special Register Read.
|
| In some implementations, data are staged in a single shared buffer,
| and a full cache line at a time is returned to the core which made the
| Special Register Read. On parts vulnerable to MFBDS or TAA, an
| attacker may be able to access stale data requested by other cores in
| the system.
|
| For more details, see:
| https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00320.html
|
|
| An attacker, which could include a malicious untrusted user process on
| a trusted guest, or an untrusted guest, can sample the contents of
| certain off-core accesses by other cores in the system.
|
| This can include data whose use may depend on the secrecy of the
| value, such as data from the Random Number Generator (e.g.
| RDRAND/RDSEED instructions).
This is yet another CPU hardware bug related to speculative execution.
Only Intel processors are affected. The RDRAND instruction became
available in Intel processors starting with Ivy Bridge (3rd gen Intel
Core). See Intel's advisory for a full list of affected CPUs. (Short
version: Most mobile/desktop CPUs are affected, while most Atoms and
server Xeons are not.)
Impact
=======
An attacker can obtain data returned by RDRAND/RDSEED instructions on
another core on the system (including another VM). In practice, Linux
does use RDRAND/RDSEED to seed its random number generator
(/dev/urandom, getrandom(2) etc.), but RDRAND/RDSEED is not the only
source of entropy. So, as long as other sources of entropy are not
compromised, the overall security of the random number generator is
still preserved. In Qubes OS, the situation is further improved by
seeding the random number generator at VM startup using a random seed
provided from dom0. This means that using Linux's random number
generator is still safe in Qubes.
Aside from the Linux kernel using RDRAND/RDSEED as one of its entropy
sources, userspace applications can also issue RDRAND/RDSEED
instructions on their own. Such software is also affected by the bug
described here. The specific impact on such software depends on what the
application does with the random data obtained in this manner.
Patching
=========
Intel has provided a microcode update that mitigates the issue. Please
note that Ivy Bridge processors are considered retired by Intel and no
longer receive microcode updates. This means that Ivy Bridge processors
will remain vulnerable to this issue. To mitigate the problem, we are
https://www.qubes-os.org/news/2020/06/11/qsb-057/
We have just published Qubes Security Bulletin (QSB) #057:
Special Register Buffer speculative side channel (XSA-320).
The text of this QSB is reproduced below. This QSB and its accompanying
signatures will always be available in the Qubes Security Pack (qubes-secpack).
View QSB #057 in the qubes-secpack:
https://github.com/QubesOS/qubes-secpack/blob/master/QSBs/qsb-057-2020.txt
Learn about the qubes-secpack, including how to obtain, verify, and read it:
https://www.qubes-os.org/security/pack/
View all past QSBs:
https://www.qubes-os.org/security/bulletins/
View XSA-320 in the XSA Tracker:
https://www.qubes-os.org/security/xsa/#320
---===[ Qubes Security Bulletin #57 ]===---
2020-06-11
Special Register Buffer speculative side channel (XSA-320)
Summary
========
On 2020-06-09, the Xen Security Team published Xen Security Advisory
320 (CVE-2020-0543 / XSA-320) [1] with the following denoscription:
| This issue is related to the MDS and TAA vulnerabilities. Please see
| https://xenbits.xen.org/xsa/advisory-297.html (MDS) and
| https://xenbits.xen.org/xsa/advisory-305.html (TAA) for details.
|
| Certain processor operations microarchitecturally need to read data
| from outside the physical core (e.g. to communicate with the random
| number generator). In some implementations, this operation is called
| a Special Register Read.
|
| In some implementations, data are staged in a single shared buffer,
| and a full cache line at a time is returned to the core which made the
| Special Register Read. On parts vulnerable to MFBDS or TAA, an
| attacker may be able to access stale data requested by other cores in
| the system.
|
| For more details, see:
| https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-00320.html
|
|
| An attacker, which could include a malicious untrusted user process on
| a trusted guest, or an untrusted guest, can sample the contents of
| certain off-core accesses by other cores in the system.
|
| This can include data whose use may depend on the secrecy of the
| value, such as data from the Random Number Generator (e.g.
| RDRAND/RDSEED instructions).
This is yet another CPU hardware bug related to speculative execution.
Only Intel processors are affected. The RDRAND instruction became
available in Intel processors starting with Ivy Bridge (3rd gen Intel
Core). See Intel's advisory for a full list of affected CPUs. (Short
version: Most mobile/desktop CPUs are affected, while most Atoms and
server Xeons are not.)
Impact
=======
An attacker can obtain data returned by RDRAND/RDSEED instructions on
another core on the system (including another VM). In practice, Linux
does use RDRAND/RDSEED to seed its random number generator
(/dev/urandom, getrandom(2) etc.), but RDRAND/RDSEED is not the only
source of entropy. So, as long as other sources of entropy are not
compromised, the overall security of the random number generator is
still preserved. In Qubes OS, the situation is further improved by
seeding the random number generator at VM startup using a random seed
provided from dom0. This means that using Linux's random number
generator is still safe in Qubes.
Aside from the Linux kernel using RDRAND/RDSEED as one of its entropy
sources, userspace applications can also issue RDRAND/RDSEED
instructions on their own. Such software is also affected by the bug
described here. The specific impact on such software depends on what the
application does with the random data obtained in this manner.
Patching
=========
Intel has provided a microcode update that mitigates the issue. Please
note that Ivy Bridge processors are considered retired by Intel and no
longer receive microcode updates. This means that Ivy Bridge processors
will remain vulnerable to this issue. To mitigate the problem, we are