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Advanced Encryption Options Land in the YaST Partitioner

October 9th, 2019 by

Welcome to a new sneak peek on the YaST improvements you will enjoy in SLE-15-SP2 and openSUSE Leap 15.2… or much earlier if you, as most YaST developers, are a happy user of openSUSE Tumbleweed.

In our report of the 84th sprint we mentioned some changes regarding the encryption capabilities of the YaST Partitioner, like displaying the concrete encryption technology or the possibility to keep an existing encryption layer.

Keeping the previous encryption layer

And the report of sprint 85 contained a promise about a separate blog post detailing the new possibilities we have been adding when it comes to create encrypted devices.

So here we go! But let’s start with a small disclaimer. Although some of the new options are available for all (open)SUSE users, it’s fair to say that this time the main beneficiaries are the users of s390 systems, which may enjoy up to four new ways of encrypting their devices.

Good Things don’t Need to Change

As you may know, so far the YaST Partitioner offered an “Encrypt Device” checkbox when creating or editing a block device. If such box is marked, the Partitioner asks for an encryption password and creates a LUKS virtual device on top of the device being encrypted.

LUKS (Linux Unified Key Setup) is the standard for Linux hard disk encryption. By providing a standard on-disk-format, it facilitates compatibility among distributions. LUKS stores all necessary setup information in the partition header, enabling to transport or migrate data seamlessly. So far, there are two format specifications for such header: LUKS1 and LUKS2. YaST uses LUKS1 because is established, solid and well-known, being fully compatible with the (open)SUSE installation process and perfectly supported by all the system tools and by most bootloaders, like Grub2.

You should not fix what is not broken. Thus, in most cases, the screen for encrypting a device has not changed at all and it still works exactly in the same way under the hood.

Editing an encrypted device

But using an alternative approach may be useful for some use cases, and we wanted to offer an option in the Partitioner for those who look for something else. So in some special cases that screen will include a new selector to choose the encryption method. Let’s analyze all those new methods.

Volatile Swap Encryption with a Random Key

When a swap device has been marked to be encrypted, the user will be able to choose between “Regular LUKS1” and “Volatile Encryption with Random Key”. Both options will be there for swap devices on all hardware architectures. The first option simply uses the classical approach described above.

Selecting the encryption method

The second one allows to configure the system in a way in which the swap device is re-encrypted on every boot with a new randomly generated password.

Encrypt swap with a random password

Some advanced users may point that configuring such a random encryption for swap was already possible in versions of openSUSE prior to Leap 15.0. But the procedure to do so was obscure to say the least. The encryption with a random password was achieved by simply leaving blank the “Enter a Password” field in the encryption step. The exact implications were not explained anywhere in the interface and the help text didn’t mention all the risks.

Now the same configuration can be achieved with a more explicit interface, relevant information is provided as you can see in the screenshot below and some extra internal controls are in place to try to limit the potential harm.

Help text for the random swap method

With this approach, the key used to encrypt the content of the swap is generated on every boot using /dev/urandom which is extremely secure. But you can always go a bit further…

Swap Encryption with Volatile Protected AES Keys

One of the nice things about having a mainframe computer (and believe us there are MANY nice things) is the extra security measures implemented at all levels. In the case of IBM Z or IBM LinuxONE that translates into the so-called pervasive encryption. Pervasive encryption is an infrastructure for end-to-end data protection. It includes data encryption with protected and secure keys.

In s390 systems offering that technology, the swap can be encrypted on every boot using a volatile protected AES key, which offers an extra level of security compared to regular encryption using data from /dev/urandom. This document explains how to setup such system by hand. But now you can just use YaST and configure everything with a single click, as shown in the following screenshot.

Encrypting swap with volatile protected keys

The good thing about this method is that you can use it even if your s390 system does not have a CCA cryptographic coprocessor. Oh, wait… you may not know what a cryptographic coprocessor is. Don’t worry, just keep reading.

Pervasive Encryption for Data Volumes

Have you ever wondered how James Bond would protect his information from the most twisted and resourceful villains? We don’t know for sure (or, at least, we are supposed to not disclosure that information), but we would bet he has an s390 system with at least one Crypto Express cryptographic coprocessor configured in CCA mode (shortly referred as a CCA coprocessor).

Those dedicated pieces of hardware, when properly combined with CPU with CPACF support, make sure the information at-rest in any storage device can only be read in the very same system where that information was encrypted. They even have a physical mechanism to destroy all the keys when the hardware is removed from the machine, like the self-destruction mechanisms in the spy movies!

As documented here, the process to enjoy the full power of pervasive encryption for data volumes in Linux can be slightly complex… unless you have the YaST Partitioner at hand!

Pervasive volume encryption

As you can see in the screenshot above, the process with YaST is as simple as choosing “Pervasive Volume Encryption” instead of the classic LUKS1 that YaST uses regularly for non-swap volumes. If YaST finds in the system a secure AES key already associated to the volume being encrypted, it will use that key and the resulting encryption device will have the DeviceMapper name specified for that key. If such secure keys don’t exist, YaST will automatically register a new one for each volume.

Help for pervasive volume encryption

Pervasive encryption can be used on any volume of the system, even the root partition.

I want it all!

So far we have seen you can use protected AES keys for randomly encrypting swap and registered secure keys for protecting data volumes. But what if you want your swap to be randomly encrypted with a volatile secure AES key? After all, you have already invested time and money installing those great CCA coprocessors, let’s use them also for the random swap encryption!

If your hardware supports it, when encrypting the swap you will see a “Volatile Encryption with Secure Key” option, in addition to the other four possibilities commented above. As easy as it gets!

All possible methods for encrypting a swap

More Booting Checks in non-s390 Systems

As described in the help for pervasive volume encryption showed above, that encryption method uses LUKS2 under the hood. So we took the opportunity to improve the Partitioner checks about encryption and booting. Now, in any architecture that is not s390 the following warning will be displayed if the expert partitioner is used to place the root directory in a LUKS2 device without a separate plain /boot.

New check for booting

As mentioned, that doesn’t apply to s390 mainframes. The usage of zipl makes possible to boot Linux in those systems as long as the kernel supports the encryption technology, independently of the Grub2 (lack of) capabilities.

What’s next?

We are still working to smooth off the rough edges of the new encryption methods offered by YaST and to add AutoYaST support for them. You may have noticed that most of the improvements currently implemented will only directly benefit s390 systems… even just a subset of those. But at the current stage, we already have built the foundation for a new era of encryption support in YaSTland.

We are thinking about adding more encryption methods that could be useful for all (open)SUSE users, with general support for LUKS2 being an obvious candidate. But that’s not something we will see in the short term because there are many details to iron up first in those technologies to make then fit nicely into the current installation process.

But hey, meanwhile you can play with all the other new toys!

openSUSE OBS git mirror

September 13th, 2019 by

There was some discussion about our OBS and how in contrast Gentoo, VoidLinux or Fedora used git to track packages.

So I made an experimental openSUSE:Factory git mirror to see how well it goes and how using it feels.
The repo currently needs around 1GB but will slowly grow over time. I did not want to spend effort to import all history.

Binary files are replaced by cryptographically secure symlinks into IPFS
and I am currently providing files up to 9MB there.

If you can not run ipfs, you can still get these files through any of the public gateways like this:
curl https://ipfs.io$(readlink packages/a/aubio/aubio-0.4.9.tar.bz2) > OUTPUT

So some benefits are already obvious.
It is now much easier to find and download our patches.
Downloading and seaching all of openSUSE is now much faster.
And it works even on Thursdays (when our maintenance window often causes OBS downtimes).

It is meant to be a read-only mirror, so there is no point in opening pull-requests on github.

I hope, you enjoy it and have a lot of fun…

Tricks with IPFS

August 7th, 2019 by

Since April I am using IPFS

Now I wanted to document some neat tricks and details.

When you have the hex-encoded sha256sum of a small file – for this example let’s use the GPLv3.txt on our media –
sha256sum /ipns/opensuse.zq1.de/tumbleweed/repo/oss/GPLv3.txt
8ceb4b9ee5adedde47b31e975c1d90c73ad27b6b165a1dcd80c7c545eb65b90

Then you can use the hash to address content directly by prefixing it with /ipfs/f01551220 so it becomes

/ipfs/f015512208ceb4b9ee5adedde47b31e975c1d90c73ad27b6b165a1dcd80c7c545eb65b903

In theory this also works with SHA1 and the /ipfs/f01551114 prefix, but then you risk experiencing non-unique content like
/ipfs/f0155111438762cf7f55934b34d179ae6a4c80cadccbb7f0a

And dont even think about using MD5.

For this trick to work, the file needs to be added with ipfs add --raw-leaves and it must be a single chunk – by default 256kB or smaller, but if you do the adding, you can also use larger chunks.

Here is a decoding of the different parts of the prefix:
/ipfs/ is the common path for IPFS-addressed content
f is the multibase prefix for hex-encoded data
01 is for the CID version 1
55 is for raw binary
12 is for sha2-256 (the default hash in IPFS)
20 is for 32 byte = 256 bit length of hash

And finally, you can also access this content via the various IPFS-web-gateways:
https://ipfs.io/ipfs/f015512208ceb4b9ee5adedde47b31e975c1d90c73ad27b6b165a1dcd80c7c545eb65b903

You can also do the same trick with other multibase encodings of the same data – e.g. base2

Base2 looks pretty geeky, but so far I have not found practical applications.

experimental openSUSE mirror via IPFS

April 3rd, 2019 by

The InterPlanetary File System (IPFS) can be used to provide files in a more efficient and distributed way than HTTP.

Our filesystem repo already has the go-ipfs client.

You use it with
ipfs daemon --init

And then you can add my Tumbleweed mirror with
zypper ar http://127.0.0.1:8080/ipns/opensuse.zq1.de./tumbleweed/repo/oss/ ipfs-oss

You can also browse the content online at
http://opensuse.zq1.de./tumbleweed/repo/oss/ . During my testing I found that the results are sometimes inappropriately cached on the Cloudflare CDN, so if you used it under this URL without the ipfs client, this might throw signature errors in zypper.

On the server side, the mirror is updated using the syncopensuse script from
https://github.com/bmwiedemann/opensusearchive and consistency of the repo is verified with checkrepo

When a complete repo was synced, dynaname updates a DNS entry to point to the new head:

> host -t txt _dnslink.opensuse.zq1.de.
_dnslink.opensuse.zq1.de is an alias for tumbleweedipfs.d.zq1.de.
tumbleweedipfs.d.zq1.de descriptive text “Last update: 2019-04-03 12:23:43 UTC”
tumbleweedipfs.d.zq1.de descriptive text “dnslink=/ipfs/QmSXEVuU5z23rDxMyFYDhSAUaGRUPswuSXD3aVsBEzucjE”

If you got spare bandwidth and 300 GB disk on some public server, you could also host a mirror of today’s version, simply by doing ipfs pin add QmSXEVuU5z23rDxMyFYDhSAUaGRUPswuSXD3aVsBEzucjE

This is a permalink: http://127.0.0.1:8080/ipfs/QmSXEVuU5z23rDxMyFYDhSAUaGRUPswuSXD3aVsBEzucjE also browsable via any public IPFS gateway. This means, it will always remain on the 20190401 version of Tumbleweed and no changes in content are possible – similar to how a git commit ID always refers to the same data.

So why did I create this IPFS mirror? That is related to my work on reproducible builds for openSUSE. There it regularly happened that published Tumbleweed binaries were built with libraries, compilers and toolchains that were no longer available in current Tumbleweed. This prevented me from verifying that the published binaries were indeed built correctly without manipulation on the OBS build workers.

Now, with this archive of rpms easily available, it was possible to verify many more Tumbleweed packages than before. And most importantly, it remains possible to independently verify even after Tumbleweed moves on to newer versions. This data is going to stay available as long as anyone pins it on a reachable server. I’m going to pin it as long as it remains relevant to me, so probably a bit until after the next full Tumbleweed rebuild – maybe 6 to 12 months.

Thus, it now is even less easy to sneak in binary backdoors during our package build process.

Report from the reproducible builds summit 2018

December 17th, 2018 by

Last week I attended the reproducible builds world summit in Paris.
It was very well organized by Holger, Gunner and their hidden helpers in the background. Very similar to the last 2 summits I attended in Berlin.

Because we were around 50 participants, introductions and announcements were the only things done in the big group. All actual work happened in 5-10 smaller circles.

We had participants from large companies like Google (with bazel), MicroSoft and Huawei, but also from many distributions and open source projects. Even MirageOS as non-Linux OS.

We did knowledge-sharing, refine definitions of terms, evolve concepts like “rebuilders” for verifying builds and allow users to better trust software they install, and such.

I learned about the undocumented DB dump (153 MB) and DB schema

And we had some hacking time, too, so there is now
a jenkins job that renders the list of unreproducible openSUSE Factory packages.

Also, my maintainer tool now has added support for the Alpine Linux distribution, thanks to help by one of its maintainers: Natanael Copa.
This is meant to help all cross-distro collaboration, not just for reproducible builds.

There is still work to be done to make better use of Mitre CPE to map package names across distributions.

I think, one major benefit of the summit was all the networking and talking going on, so that we have an easier time working with each other over the internet in the future.

Encrypted installation media

November 17th, 2017 by

Hackweek project: create encrypted installation media

  • You’re still carrying around your precious autoyast config files on an unencrypted usb stick?
  • You have a customized installation disk that could reveal lots of personal details?
  • You use ad blockers, private browser tabs, or even tor but still carry around your install or rescue disk unencrypted for everyone to see?
  • You have your personal files and an openSUSE installation tree on the same partition just because you are lazy and can’t be bothered to tidy things up?
  • A simple Linux install stick is just not geekish enough for you?

Not any longer!

mksusecd can now (well, once this pull request has been merged) create fully encrypted installation media (both UEFI and legacy BIOS bootable).

Everything (but the plain grub) is on a LUKS-encrypted partition. If you’re creating a customized boot image and add sensitive data via --boot or add an add-on repo or autoyast config or some secret driver update – this is all safe now!

You can get the latest mksusecd-1.54 already here to try it out! (Or visit software.opensuse.org and look for (at least) version 1.54 under ‘Show other versions’.

It’s as easy as

mksusecd --create crypto.img --crypto --password=xxx some_tumbleweed.iso

And then dd the image to your usb stick.

But if your Tumbleweed or SLE/Leap 15 install media are a bit old (well, as of now they are) check the ‘Crypto notes’ in mksusecd --help first! – You will need to add two extra options.

This is how the first screen looks then

Developing with OpenSSL 1.1.x on openSUSE Leap

August 18th, 2017 by

The SUSE OpenSSL maintainers are hard at work to migrate openSUSE Tumbleweed and SUSE Linux Enterprise 15 to use OpenSSL 1.1 by default. Some work remains, see boo#1042629.

Here is how you can use OpenSSL 1.1 in parallel to the 1.0 version on openSUSE Leap for development and run-time:
(more…)

Manual encryption partition setup for stronger full disk encryption

May 26th, 2017 by

When installing openSUSE or SUSE Linux Enterprise, YaST is able to configure encrypted LVM using LUKS for full disk encryption. The default configuration is aes-xts-plain64 using a 256 bit master key. However, due to how the XTC mode splits the key into two halves, this reduces the effective key size used for AES to 128 Bits.

In order to use a 512 bit key for 256 effective AES, one needs to perform manual formatting prior to installation:
cryptsetup LuksFormat --key-size 512 /dev/sda1
However the installer suffers from boo#1030299 which prevents it from writing an entry to /etc/crypttab in this instance. This results in a system that is unable to boot after installation.

The work-around is as follows: Boot into the rescue system, open the crypto device and enter the installed system as a chroot:

cryptsetup luksOpen /dev/sda1 crypto
mount /dev/mapper/system-root /mnt
for X in proc dev sys; do mount -bind /$ /mnt/$X; done
chroot /mnt

(This example assumes /dev/sda1 to be the crypto device, and an LVM VG named system with a LV named root, and no separate /boot.)

Then in the chroot, edit /etc/crypttab to have the following line:

crypto /dev/sda1 none none

See man crypttab for additional settings and options. To finalize, regenerate the initrd and reboot

mkinitrd
exit
reboot

A future rewrite of the YaST storage abstraction layer is planned which should address this issue.

YaST development during Hack Week 15

March 7th, 2017 by

During this Hack Week, some of our team members invested quite some time working in YaST related projects. But, what’s even better, some people from outside the team worked also in YaST projects. Thank you guys!

So let’s summarize those projects and also some extra ones from our team members.

Let’s Encrypt made easy in openSUSE

Daniel Molkentin enjoyed his first Hack Week working together with Klaas Freitag to bring Let’s Encrypt integration to openSUSE. Although they didn’t had experience with YaST development, they followed the YaST tutorial and created a new brand yast-acme module. It’s still a work in progress, but it looks promising.

Managing certificates

You can get more details reading the Daniel Molkentin’s blog post about the project.

Removing perl-apparmor dependency

Goldwyn Rodrigues worked to remove the dependency of yast-apparmor on (now obsolete) perl-apparmor. There’s quite some work to do, but he’s heading in the right direction.

Find out more about the project in the Hack Week page and in Goldwyn’s fork.

gfxboot for grub2

Steffen Winterfeldt was working in gfxboot2, an attempt to provide a graphical user interface for grub2. Although it’s still a work in progress, it looks really good: module works for grub2-legacy and grub2-efi, basic font rendering is in place, language primitives are partly implemented, the integrated debugger already works…

You can find further information in the projects page.

YaST Integration Tests using Cucumber

The YaST team is always trying to improve their testing tools so Ladislav Slezák has been working in a proof of concept to use Cucumber to run YaST integration tests and the results are pretty impressive. The prototype is able to test YaST in an installed system, during installation and it can be used even for plain libyui applications outside YaST.

Test adding repository

Check out the details at project’s page and at Ladislav’s blog.

Keep working on libstorage-ng

If you follow YaST development, you know that the team is making good progress towards replacing the old libstorage. And even during Hack Week, libstorage-ng got some love from our hackers.

Arvin Schnell implemented support for more filesystems in libstorage-ng: ext2, ext3, ReiserFS, ISO 9660, UDF and basic support for NFS.

Iván López invested his first Hack Week improving yast2-storage-ng. Read this description to find out more information about the changes.

And last but not least, apart from helping Iván with his project, Ancor González worked in a new approach for yast2-storage-ng: instead of just extending the API offered by libstorage-ng, the idea is to wrap the library so the Ruby code using yast2-storage-ng does not have direct visibility on the libstorage-ng classes and methods.

More Ruby in YaST

Josef Reidinger is trying to reduce the amount of code in other languages different than Ruby. He successfully replaced the binary y2base with a Ruby version (not merged yet) and reduced the amount of Perl code in the yast2 package.

You can check the progress in yast-ruby-bindings#191 and yast-yast2#540 pull requests.

Support for Salt parametrizable formulas

YaST2 CM was born in 2016 as a proof of concept to somehow integrate AutoYaST with Software Configuration Management systems like Salt or Puppet.

During this Hack Week, Duncan Mac Vicar and Imobach González were working to implement support for Salt parametrizable formulas. You can find out more information in this post at Imobach’s blog.

Other non-YaST projects

Hack Week allows us to work in any project we want, so there’re also some non-YaST related projects that we would like to mention.

Improved QDirStat

QDirStat is a Qt-based tool which offers directory statistics. His author, Stefan Hundhammer,implemented some new features (like a better behavior when hovering over a tree map or improved logging) and fixed some bugs. Find out more details in the project’s README and the version 1.3 release notes.

He also wrote an article about how to use the application in headless systems (no X server, no Xlibs).

Current version is already available at software.opensuse.org so you could consider giving it a try.

Learning new things

Hack Week is a great opportunity to play with new stuff. With that idea in mind, Martin Vidner learned about Android development and wrote detailed instructions for starting with that: Getting Started in Android Development: Part 1: Building the First App, Part 2: Publishing the First App and Part 3: Reducing Bloat.

Knut Anderssen decided to try also some mobile development and enjoyed playing around with the Ionic.

And that’s all! After Hack Week, we’re back to SCRUM and we’re now working sprint 32. We’ll give you additional details in our next “Highlights of YaST development” report.

Stay tunned!

Official RPM package : OWASP ZAP

January 6th, 2017 by

The world is going through a security crisis, so I make the official packages available in openSUSE, SUSE Enterprise, CentOS, Fedora e RedHat.

Thank you, Mauro Risonho de Paula Assumção e Simon Bennetts.

Link for download: https://software.opensuse.org/download.html?project=home%3Acabelo&package=owasp-zap