The absolute number may not be impressive, but what I hope is at least a useful contribution is that there actually is a number on how much of Trisquel is reproducible. Hopefully this will inspire others to help improve the actual metric.
When I set about to understand how Trisquel worked, I identified a number of things that would improve my confidence in it. The lowest hanging fruit for me was to manually audit the package archive, and I wrote a tool called debdistdiff to automate this for me. That led me to think about apt archive transparency more in general. I have made some further work in that area (hint: apt-verify) that deserve its own blog post eventually. Most of apt archive transparency is futile if we don’t trust the intended packages that are in the archive. One way to measurable increase trust in the package are to provide reproducible builds of the packages, which should by now be an established best practice. Code review is still important, but since it will never provide positive guarantees we need other processes that can identify sub-optimal situations automatically. The way reproducible builds easily identify negative results is what I believe has driven much of its success: its results are tangible and measurable. The field of software engineering is in need of more such practices.
The design of my setup to build Trisquel reproducible are as follows.
The project debdistget is responsible for downloading Release/Packages files (which are the most relevant files from dists/) from apt archives, and works by commiting them into GitLab-hosted git-repositories. I maintain several such repositories for popular apt-archives, including for Trisquel and its upstream Ubuntu. GitLab invokes a schedule pipeline to do the downloading, and there is some race conditions here.
The project debdistdiff is used to produce the list of added and modified packages, which are the input to actually being able to know what packages to reproduce. It publishes human readable summary of difference for several distributions, including Trisquel vs Ubuntu. Early on I decided that rebuilding all of the upstream Ubuntu packages is out of scope for me: my personal trust in the official Debian/Ubuntu apt archives are greater than my trust of the added/modified packages in Trisquel.
The final project reproduce-trisquel puts the pieces together briefly as follows, everything being driven from its .gitlab-ci.yml file.
There is a (manually triggered) job generate-build-image to create a build image to speed up CI/CD runs, using a simple Dockerfile.
There is a (manually triggered) job generate-package-lists that uses debdistdiff to generate and store package lists and puts its output in lists/. The reason this is manually triggered right now is due to a race condition.
There is a (scheduled) job that does two things: from the package lists, the script generate-ci-packages.sh builds a GitLab CI/CD instruction file ci-packages.yml that describes jobs for each package to build. The second part is generate-readme.sh that re-generate the project’s README.md based on the build logs and diffoscope outputs that stored in the git repository.
Through the ci-packages.yml file, there is a large number of jobs that are dynamically defined, which currently are manually triggered to not overload the build servers. The script build-package.sh is invoked and attempts to rebuild a package, and stores build log and diffoscope output in the git project itself.
I did not expect to be able to use the GitLab shared runners to do the building, however they turned out to work quite well and I postponed setting up my own runner. There is a manually curated lists/disabled-aramo.txt with some packages that all required too much disk space or took over two hours to build. Today I finally took the time to setup a GitLab runner using podman running Trisquel aramo, and I expect to complete builds of the remaining packages soon — one of my Dell R630 server with 256GB RAM and dual 2680v4 CPUs should deliver sufficient performance.
Current limitations and ideas on further work (most are filed as project issues) include:
We don’t support *.buildinfo files. As far as I am aware, Trisquel does not publish them for their builds. Improving this would be a first step forward, anyone able to help? Compare buildinfo.debian.net. For example, many packages differ only in their NT_GNU_BUILD_ID symbol inside the ELF binary, see example diffoscope output for libgpg-error. By poking around in jenkins.trisquel.org I managed to discover that Trisquel built initramfs-utils in the randomized path /build/initramfs-tools-bzRLUp and hard-coding that path allowed me to reproduce that package. I expect the same to hold for many other packages. Unfortunately, this failure turned into success with that package moved the needle from 42% reproducibility to 43% however I didn’t let that stand in the way of a good headline.
The mechanism to download the Release/Package-files from dists/ is not fool-proof: we may not capture all ever published such files. While this is less of a concern for reproducibility, it is more of a concern for apt transparency. Still, having Trisquel provide a service similar to snapshot.debian.org would help.
Having at least one other CPU architecture would be nice.
Due to lack of time and mental focus, handling incremental updates of new versions of packages is not yet working. This means we only ever build one version of a package, and never discover any newly published versions of the same package. Now that Trisquel aramo is released, the expected rate of new versions should be low, but still happens due to security or backports.
Porting this to test supposedly FSDG-compliant distributions such as PureOS and Gnuinos should be relatively easy. I’m also looking at Devuan because of Gnuinos.
The elephant in the room is how reproducible Ubuntu is in the first place.
Happy Easter Hacking!
Update 2023-04-17: The original project “reproduce-trisquel” that was announced here has been archived and replaced with two projects, one generic “debdistreproduce” and one with results for Trisquel: “reproduce/trisquel“.
I’ve always found the operation of apt software package repositories to be a mystery. There appears to be a lack of transparency into which people have access to important apt package repositories out there, how the automatic non-human update mechanism is implemented, and what changes are published. I’m thinking of big distributions like Ubuntu and Debian, but also the free GNU/Linux distributions like Trisquel and PureOS that are derived from the more well-known distributions.
As far as I can tell, anyone who has the OpenPGP private key trusted by a apt-based GNU/Linux distribution can sign a modified Release/InRelease file and if my machine somehow downloads that version of the release file, my machine could be made to download and install packages that the distribution didn’t intend me to install. Further, it seems that anyone who has access to the main HTTP server, or any of its mirrors, or is anywhere on the network between them and my machine (when plaintext HTTP is used), can either stall security updates on my machine (on a per-IP basis), or use it to send my machine (again, on a per-IP basis to avoid detection) a modified Release/InRelease file if they had been able to obtain the private signing key for the archive. These are mighty powers that warrant overview.
I’ve always put off learning about the processes to protect the apt infrastructure, mentally filing it under “so many people rely on this infrastructure that enough people are likely to have invested time reviewing and improving these processes”. Simultaneous, I’ve always followed the more free-software friendly Debian-derived distributions such as gNewSense and have run it on some machines. I’ve never put them into serious production use, because the trust issues with their apt package repositories has been a big question mark for me. The “enough people” part of my rationale for deferring this is not convincing. Even the simple question of “is someone updating the apt repository” is not easy to understand on a running gNewSense system. At some point in time the gNewSense cron job to pull in security updates from Debian must have stopped working, and I wouldn’t have had any good mechanism to notice that. Most likely it happened without any public announcement. I’ve recently switched to Trisquel on production machines, and these questions has come back to haunt me.
The situation is unsatisfying and I looked into what could be done to improve it. I could try to understand who are the key people involved in each project, and may even learn what hardware component is used, or what software is involved to update and sign apt repositories. Is the server running non-free software? Proprietary BIOS or NIC firmware? Are the GnuPG private keys on disk? Smartcard? TPM? YubiKey? HSM? Where is the server co-located, and who has access to it? I tried to do a bit of this, and discovered things like Trisquel having a DSA1024 key in its default apt trust store (although for fairness, it seems that apt by default does not trust such signatures). However, I’m not certain understanding this more would scale to securing my machines against attacks on this infrastructure. Even people with the best intentions, and the state of the art hardware and software, will have problems.
To increase my trust in Trisquel I set out to understand how it worked. To make it easier to sort out what the interesting parts of the Trisquel archive to audit further were, I created debdistdiff to produce human readable text output comparing one apt archive with another apt archive. There is a GitLab CI/CD cron job that runs this every day, producing output comparing Trisquel vs Ubuntu and PureOS vs Debian. Working with these output files has made me learn more about how the process works, and I even stumbled upon something that is likely a bug where Trisquel aramo was imported from Ubuntu jammy while it contained a couple of package (e.g., gcc-8, python3.9) that were removed for the final Ubuntu jammy release.
After working on auditing the Trisquel archive manually that way, I realized that whatever I could tell from comparing Trisquel with Ubuntu, it would only be something based on a current snapshot of the archives. Tomorrow it may look completely different. What felt necessary was to audit the differences of the Trisquel archive continously. I was quite happy to have developed debdistdiff for one purpose (comparing two different archives like Trisquel and Ubuntu) and discovered that the tool could be used for another purpose (comparing the Trisquel archive at two different points in time). At this time I realized that I needed a log of all different apt archive metadata to be able to produce an audit log of the differences in time for the archive. I create manually curated git-repositories with the Release/InRelease and the Packages files for each architecture/component of the well-known distributions Trisquel, Ubuntu, Debian and PureOS. Eventually I wrote scripts to automate this, which are now published in the debdistget project.
At this point, one of the early question about per-IP substitution of Release files were lingering in my mind. However with the tooling I now had available, coming up with a way to resolve this was simple! Merely have apt compute a SHA256 checksum of the just downloaded InRelease file, and see if my git repository had the same file. At this point I started reading the Apt source code, and now I had more doubts about the security of my systems than I ever had before. Oh boy how the name Apt has never before felt more… Apt?! Oh well, we must leave some exercises for the students. Eventually I realized I wanted to touch as little of apt code basis as possible, and noticed the SigVerify::CopyAndVerify function called ExecGPGV which called apt-key verify which called GnuPG’s gpgv. By setting Apt::Key::gpgvcommand I could get apt-key verify to call another tool than gpgv. See where I’m going? I thought wrapping this up would now be trivial but for some reason the hash checksum I computed locally never matched what was on my server. I gave up and started working on other things instead.
Today I came back to this idea, and started to debug exactly how the local files looked that I got from apt and how they differed from what I had in my git repositories, that came straight from the apt archives. Eventually I traced this back to SplitClearSignedFile which takes an InRelease file and splits it into two files, probably mimicking the (old?) way of distributing both Release and Release.gpg. So the clearsigned InRelease file is split into one cleartext file (similar to the Release file) and one OpenPGP signature file (similar to the Release.gpg file). But why didn’t the cleartext variant of the InRelease file hash to the same value as the hash of the Release file? Sadly they differ by the final newline.
Having solved this technicality, wrapping the pieces up was easy, and I came up with a project apt-canary that provides a script apt-canary-gpgv that verify the local apt release files against something I call a “apt canary witness” file stored at a URL somewhere.
I’m now running apt-canary on my Trisquel aramo laptop, a Trisquel nabia server, and Talos II ppc64el Debian machine. This means I have solved the per-IP substitution worries (or at least made them less likely to occur, having to send the same malicious release files to both GitLab and my system), and allow me to have an audit log of all release files that I actually use for installing and downloading packages.
What do you think? There are clearly a lot of work and improvements to be made. This is a proof-of-concept implementation of an idea, but instead of refining it until perfection and delaying feedback, I wanted to publish this to get others to think about the problems and various ways to resolve them.
Btw, I’m going to be at FOSDEM’23 this weekend, helping to manage the Security Devroom. Catch me if you want to chat about this or other things. Happy Hacking!
Ever wondered how Trisquel and Ubuntu differs and what’s behind the curtain from a developer perspective? I have. Sharing what I’ve learnt will allow you to increase knowledge and trust in Trisquel too.
Trisquel GNU/Linux logo
The scripts to convert an Ubuntu archive into a Trisquel archive are available in the ubuntu-purge repository. The easy to read purge-focal script lists the packages to remove from Ubuntu 20.04 Focal when it is imported into Trisquel 10.0 Nabia. The purge-jammy script provides the same for Ubuntu 22.04 Jammy and (the not yet released) Trisquel 11.0 Aramo. The list of packages is interesting, and by researching the reasons for each exclusion you can learn a lot about different attitudes towards free software and understand the desire to improve matters. I wish there were a wiki-page that for each removed package summarized relevant links to earlier discussions. At the end of the script there is a bunch of packages that are removed for branding purposes that are less interesting to review.
Trisquel adds a couple of Trisquel-specific packages. The source code for these packages are in the trisquel-packages repository, with sub-directories for each release: see 10.0/ for Nabia and 11.0/ for Aramo. These packages appears to be mostly for branding purposes.
Trisquel modify a set of packages, and here is starts to get interesting. Probably the most important package to modify is to use GNU Linux-libre instead of Linux as the kernel. The scripts to modify packages are in the package-helpers repository. The relevant scripts are in the helpers/ sub-directory. There is a branch for each Trisquel release, see helpers/ for Nabia and helpers/ for Aramo. To see how Linux is replaced with Linux-libre you can read the make-linux script.
This covers the basic of approaching Trisquel from a developers perspective. As a user, I have identified some areas that need more work to improve trust in Trisquel:
Auditing the Trisquel archive to confirm that the intended changes covered above are the only changes that are published.
Rebuild all packages that were added or modified by Trisquel and publish diffoscope output comparing them to what’s in the Trisquel archive. The goal would be to have reproducible builds of all Trisquel-related packages.
Publish an audit log of the Trisquel archive to allow auditing of what packages are published. This boils down to trust of the OpenPGP key used to sign the Trisquel archive.
Trisquel archive mirror auditing to confirm that they are publishing only what comes from the official archive, and that they do so timely.
I hope to publish more about my work into these areas. Hopefully this will inspire similar efforts in related distributions like PureOS and the upstream distributions Ubuntu and Debian.
I’m migrating some self-hosted virtual machines to Trisquel, and noticed that Trisquel does not offer cloud-images similar to the Debian Cloud and Ubuntu Cloud images. Thus my earlier approach based on virt-install --cloud-init and cloud-localds does not work with Trisquel. While I hope that Trisquel will eventually publish cloud-compatible images, I wanted to document an alternative approach for Trisquel based on preseeding. This is how I used to install Debian and Ubuntu in the old days, and the automated preseed method is best documented in the Debian installation manual. I was hoping to forget about the preseed format, but maybe it will become one of those legacy technologies that never really disappears? Like FAT16 and 8-bit microcontrollers.
Below I assume you have a virtual machine host server up that runs libvirt and has virt-install and similar tools; install them with the following command. I run Trisquel 11 aramo on my VM-host, but I believe any recent dpkg-based distribution like Trisquel 9/10, PureOS 10, Debian 11 or Ubuntu 20.04/22.04 would work with minor adjustments.
I have developed the following fairly minimal preseed file that works with all three Trisquel releases. Compare it against the official Trisquel 11 preseed skeleton and the Debian 11 example preseed file. You should modify obvious things like SSH key, host/IP settings, partition layout and decide for yourself how to deal with passwords. While Ubuntu/Trisquel usually wants to setup a user account, I prefer to login as root hence setting ‘passwd/root-login‘ to true and ‘passwd/make-user‘ to false.
Use the file above as a skeleton for preparing a VM-specific preseed file as follows. The environment variables HOST and IPS will be used later on too.
The following script is used to prepare the ISO images with the preseed file that we will need. This script is inspired by the Debian Wiki Preseed EditIso page and the Trisquel ISO customization wiki page. There are a couple of variations based on earlier works. Paths are updated to match the Trisquel netinst ISO layout, which differ slightly from Debian. We modify isolinux.cfg to boot the auto label without a timeout. On Trisquel 11 the auto boot label exists, but on Trisquel 9 and Trisquel 10 it does not exist so we add it in order to be able to start the automated preseed installation.
root@trana:~# cat gen-preseed-iso
#!/bin/sh
# Copyright (C) 2018-2022 Simon Josefsson -- GPLv3+
# https://wiki.debian.org/DebianInstaller/Preseed/EditIso
# https://trisquel.info/en/wiki/customizing-trisquel-iso
set -e
set -x
ISO="$1"
PRESEED="$2"
OUTISO="$3"
LASTPWD="$PWD"
test -f "$ISO"
test -f "$PRESEED"
test ! -f "$OUTISO"
TMPDIR=$(mktemp -d)
mkdir "$TMPDIR/mnt"
mkdir "$TMPDIR/tmp"
cp "$PRESEED" "$TMPDIR"/preseed.cfg
cd "$TMPDIR"
mount "$ISO" mnt/
cp -rT mnt/ tmp/
umount mnt/
chmod +w -R tmp/
gunzip tmp/initrd.gz
echo preseed.cfg | cpio -H newc -o -A -F tmp/initrd
gzip tmp/initrd
chmod -w -R tmp/
sed -i "s/timeout 0/timeout 1/" tmp/isolinux.cfg
sed -i "s/default vesamenu.c32/default auto/" tmp/isolinux.cfg
if ! grep -q auto tmp/adtxt.cfg; then
cat<<EOF >> tmp/adtxt.cfg
label auto
menu label ^Automated install
kernel linux
append auto=true priority=critical vga=788 initrd=initrd.gz --- quiet
EOF
fi
cd tmp/
find -follow -type f | xargs md5sum > md5sum.txt
cd ..
cd "$LASTPWD"
genisoimage -r -J -b isolinux.bin -c boot.cat \
-no-emul-boot -boot-load-size 4 -boot-info-table \
-o "$OUTISO" "$TMPDIR/tmp/"
rm -rf "$TMPDIR"
exit 0
^D
root@trana:~# chmod +x gen-preseed-iso
root@trana:~#
Next run the command on one of the downloaded ISO image and the generated preseed file.
root@trana:~# ./gen-preseed-iso /root/iso/trisquel-netinst_10.0.1_amd64.iso vm-$HOST.preseed vm-$HOST.iso
+ ISO=/root/iso/trisquel-netinst_10.0.1_amd64.iso
+ PRESEED=vm-foo.preseed
+ OUTISO=vm-foo.iso
+ LASTPWD=/root
+ test -f /root/iso/trisquel-netinst_10.0.1_amd64.iso
+ test -f vm-foo.preseed
+ test ! -f vm-foo.iso
+ mktemp -d
+ TMPDIR=/tmp/tmp.mNEprT4Tx9
+ mkdir /tmp/tmp.mNEprT4Tx9/mnt
+ mkdir /tmp/tmp.mNEprT4Tx9/tmp
+ cp vm-foo.preseed /tmp/tmp.mNEprT4Tx9/preseed.cfg
+ cd /tmp/tmp.mNEprT4Tx9
+ mount /root/iso/trisquel-netinst_10.0.1_amd64.iso mnt/
mount: /tmp/tmp.mNEprT4Tx9/mnt: WARNING: source write-protected, mounted read-only.
+ cp -rT mnt/ tmp/
+ umount mnt/
+ chmod +w -R tmp/
+ gunzip tmp/initrd.gz
+ echo preseed.cfg
+ cpio -H newc -o -A -F tmp/initrd
5 blocks
+ gzip tmp/initrd
+ chmod -w -R tmp/
+ sed -i s/timeout 0/timeout 1/ tmp/isolinux.cfg
+ sed -i s/default vesamenu.c32/default auto/ tmp/isolinux.cfg
+ grep -q auto tmp/adtxt.cfg
+ cat
+ cd tmp/
+ find -follow -type f
+ xargs md5sum
+ cd ..
+ cd /root
+ genisoimage -r -J -b isolinux.bin -c boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -o vm-foo.iso /tmp/tmp.mNEprT4Tx9/tmp/
I: -input-charset not specified, using utf-8 (detected in locale settings)
Using GCRY_000.MOD;1 for /tmp/tmp.mNEprT4Tx9/tmp/boot/grub/x86_64-efi/gcry_sha512.mod (gcry_sha256.mod)
Using XNU_U000.MOD;1 for /tmp/tmp.mNEprT4Tx9/tmp/boot/grub/x86_64-efi/xnu_uuid.mod (xnu_uuid_test.mod)
Using PASSW000.MOD;1 for /tmp/tmp.mNEprT4Tx9/tmp/boot/grub/x86_64-efi/password_pbkdf2.mod (password.mod)
Using PART_000.MOD;1 for /tmp/tmp.mNEprT4Tx9/tmp/boot/grub/x86_64-efi/part_sunpc.mod (part_sun.mod)
Using USBSE000.MOD;1 for /tmp/tmp.mNEprT4Tx9/tmp/boot/grub/x86_64-efi/usbserial_pl2303.mod (usbserial_ftdi.mod)
Using USBSE001.MOD;1 for /tmp/tmp.mNEprT4Tx9/tmp/boot/grub/x86_64-efi/usbserial_ftdi.mod (usbserial_usbdebug.mod)
Using VIDEO000.MOD;1 for /tmp/tmp.mNEprT4Tx9/tmp/boot/grub/x86_64-efi/videotest.mod (videotest_checksum.mod)
Using GFXTE000.MOD;1 for /tmp/tmp.mNEprT4Tx9/tmp/boot/grub/x86_64-efi/gfxterm_background.mod (gfxterm_menu.mod)
Using GCRY_001.MOD;1 for /tmp/tmp.mNEprT4Tx9/tmp/boot/grub/x86_64-efi/gcry_sha256.mod (gcry_sha1.mod)
Using MULTI000.MOD;1 for /tmp/tmp.mNEprT4Tx9/tmp/boot/grub/x86_64-efi/multiboot2.mod (multiboot.mod)
Using USBSE002.MOD;1 for /tmp/tmp.mNEprT4Tx9/tmp/boot/grub/x86_64-efi/usbserial_usbdebug.mod (usbserial_common.mod)
Using MDRAI000.MOD;1 for /tmp/tmp.mNEprT4Tx9/tmp/boot/grub/x86_64-efi/mdraid09.mod (mdraid09_be.mod)
Size of boot image is 4 sectors -> No emulation
22.89% done, estimate finish Thu Dec 29 23:36:18 2022
45.70% done, estimate finish Thu Dec 29 23:36:18 2022
68.56% done, estimate finish Thu Dec 29 23:36:18 2022
91.45% done, estimate finish Thu Dec 29 23:36:18 2022
Total translation table size: 2048
Total rockridge attributes bytes: 24816
Total directory bytes: 40960
Path table size(bytes): 64
Max brk space used 46000
21885 extents written (42 MB)
+ rm -rf /tmp/tmp.mNEprT4Tx9
+ exit 0
root@trana:~#
Now the image is ready for installation, so invoke virt-install as follows. For older virt-install (for example on Trisquel 10 nabia), replace --osinfo linux2020 with --os-variant linux2020.The machine will start directly, launching the preseed automatic installation. At this point, I usually click on the virtual machine in virt-manager to follow screen output until the installation has finished. If everything works OK the machines comes up and I can ssh into it.
root@trana:~# virt-install --name $HOST --disk vm-$HOST.img,size=5 --cdrom vm-$HOST.iso --osinfo linux2020 --autostart --noautoconsole --wait
Using linux2020 default --memory 4096
Starting install...
Allocating 'vm-foo.img' | 0 B 00:00:00 ...
Creating domain... | 0 B 00:00:00
Domain is still running. Installation may be in progress.
Waiting for the installation to complete.
Domain has shutdown. Continuing.
Domain creation completed.
Restarting guest.
root@trana:~#
There are some problems that I have noticed that would be nice to fix, but are easy to work around. The first is that at the end of the installation of Trisquel 9 and Trisquel 10, the VM hangs after displaying Sent SIGKILL to all processes followed by Requesting system reboot. I kill the VM manually using virsh destroy foo and start it up again using virsh start foo. For production use I expect to be running Trisquel 11, where the problem doesn’t happen, so this does not bother me enough to debug further.
Update 2023-03-21: The following issue was fixed between the final release of aramo and the pre-release of aramo that this blog post was originally written for, so the following no longer applies: The remaining issue that once booted, a Trisquel 11 VM has lost its DNS nameserver configuration, presumably due to poor integration with systemd-resolved. Both Trisquel 9 and Trisquel 10 uses systemd-resolved where DNS works after first boot, so this appears to be a Trisquel 11 bug. You can work around it with rm -f /etc/resolv.conf && echo 'nameserver A.B.C.D' > /etc/resolv.conf or drink the systemd Kool-Aid.
If you want to clean up and re-start the process, here is how you wipe out what you did. After this, you may run the sed, ./gen-preseed-iso and virt-install commands again. Remember, use virsh shutdown foo to gracefully shutdown a VM.
I use GnuPG to compute cryptographic signatures for my emails, git commits/tags, and software release artifacts (tarballs). Part of GnuPG is gpg-agent which talks to OpenSSH, which I login to remote servers and to clone git repositories. I dislike storing cryptographic keys on general-purpose machines, and have used hardware-backed OpenPGP keys since around 2006 when I got a FSFE Fellowship Card. GnuPG via gpg-agent handles this well, and the private key never leaves the hardware. The ZeitControl cards were (to my knowledge) proprietary hardware running some non-free operating system and OpenPGP implementation. By late 2012 the YubiKey NEO supported OpenPGP, and while the hardware and operating system on it was not free, at least it ran a free software OpenPGP implementation and eventually I setup my primary RSA key on it. This worked well for a couple of years, and when I in 2019 wished to migrate to a new key, the FST-01G device with open hardware running free software that supported Ed25519 had become available. I created a key and have been using the FST-01G on my main laptop since then. This little device has been working, the signature counter on it is around 14501 which means around 10 signatures/day since then!
Currently I am in the process of migrating towards a new laptop, and moving the FST-01G device between them is cumbersome, especially if I want to use both laptops in parallel. That’s why I need to setup a new hardware device to hold my OpenPGP key, which can go with my new laptop. This is a good time to re-visit alternatives. I quickly decided that I did not want to create a new key, only to import my current one to keep everything working. My requirements on the device to chose hasn’t changed since 2019, see my summary at the end of the earlier blog post. Unfortunately the FST-01G is out of stock and the newer FST-01SZ has also out of stock. While Tillitis looks promising (and I have one to play with), it does not support OpenPGP (yet). What to do? Fortunately, I found some FST-01SZ device in my drawer, and decided to use it pending a more satisfactory answer. Hopefully once I get around to generate a new OpenPGP key in a year or so, I will do a better survey of options that are available on the market then. What are your (freedom-respecting) OpenPGP hardware recommendations?
FST-01SZ circuit board
Similar to setting up the FST-01G, the FST-01SZ needs to be setup before use. I’m doing the following from Trisquel 11 but any GNU/Linux system would work. When the device is inserted at first time, some kernel messages are shown (see /var/log/syslog or use the dmesg command):
usb 3-3: new full-speed USB device number 39 using xhci_hcd
usb 3-3: New USB device found, idVendor=234b, idProduct=0004, bcdDevice= 2.00
usb 3-3: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 3-3: Product: Fraucheky
usb 3-3: Manufacturer: Free Software Initiative of Japan
usb 3-3: SerialNumber: FSIJ-0.0
usb-storage 3-3:1.0: USB Mass Storage device detected
scsi host1: usb-storage 3-3:1.0
scsi 1:0:0:0: Direct-Access FSIJ Fraucheky 1.0 PQ: 0 ANSI: 0
sd 1:0:0:0: Attached scsi generic sg2 type 0
sd 1:0:0:0: [sdc] 128 512-byte logical blocks: (65.5 kB/64.0 KiB)
sd 1:0:0:0: [sdc] Write Protect is off
sd 1:0:0:0: [sdc] Mode Sense: 03 00 00 00
sd 1:0:0:0: [sdc] No Caching mode page found
sd 1:0:0:0: [sdc] Assuming drive cache: write through
sdc:
sd 1:0:0:0: [sdc] Attached SCSI removable disk
Interestingly, the NeuG software installed on the device I got appears to be version 1.0.9:
jas@kaka:~$ head /media/jas/Fraucheky/README
NeuG - a true random number generator implementation
Version 1.0.9
2018-11-20
Niibe Yutaka
Free Software Initiative of Japan
What's NeuG?
============
jas@kaka:~$
I could not find version 1.0.9 published anywhere, but the device came with a SD-card that contain a copy of the source, so I uploaded it until a more canonical place is located. Putting the device in the serial mode can be done using a sudo eject /dev/sdc command which results in the following syslog output.
usb 3-3: reset full-speed USB device number 39 using xhci_hcd
usb 3-3: device firmware changed
usb 3-3: USB disconnect, device number 39
sdc: detected capacity change from 128 to 0
usb 3-3: new full-speed USB device number 40 using xhci_hcd
usb 3-3: New USB device found, idVendor=234b, idProduct=0001, bcdDevice= 2.00
usb 3-3: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 3-3: Product: NeuG True RNG
usb 3-3: Manufacturer: Free Software Initiative of Japan
usb 3-3: SerialNumber: FSIJ-1.0.9-42315277
cdc_acm 3-3:1.0: ttyACM0: USB ACM device
Now download Gnuk, verify its integrity and build it. You may need some additional packages installed, try apt-get install gcc-arm-none-eabi openocd python3-usb. As you can see, I’m using the stable 1.2 branch of Gnuk, currently on version 1.2.20. The ./configure parameters deserve some explanation. The kdf_do=required sets up the device to require KDF usage. The --enable-factory-reset allows me to use the command factory-reset (with admin PIN) inside gpg --card-edit to completely wipe the card. Some may consider that too dangerous, but my view is that if someone has your admin PIN it is game over anyway. The --vidpid=234b:0000 is specifies the USB VID/PID to use, and --target=FST_01SZ is critical to set the platform (you’ll may brick the device if you pick the wrong --target setting).
jas@kaka:~/src$ rm -rf gnuk neug
jas@kaka:~/src$ git clone https://gitlab.com/jas/neug.git
Cloning into 'neug'...
remote: Enumerating objects: 2034, done.
remote: Counting objects: 100% (2034/2034), done.
remote: Compressing objects: 100% (603/603), done.
remote: Total 2034 (delta 1405), reused 2013 (delta 1405), pack-reused 0
Receiving objects: 100% (2034/2034), 910.34 KiB | 3.50 MiB/s, done.
Resolving deltas: 100% (1405/1405), done.
jas@kaka:~/src$ git clone https://salsa.debian.org/gnuk-team/gnuk/gnuk.git
Cloning into 'gnuk'...
remote: Enumerating objects: 13765, done.
remote: Counting objects: 100% (959/959), done.
remote: Compressing objects: 100% (337/337), done.
remote: Total 13765 (delta 629), reused 907 (delta 599), pack-reused 12806
Receiving objects: 100% (13765/13765), 12.59 MiB | 3.05 MiB/s, done.
Resolving deltas: 100% (10077/10077), done.
jas@kaka:~/src$ cd neug
jas@kaka:~/src/neug$ git describe
release/1.0.9
jas@kaka:~/src/neug$ git tag -v `git describe`
object 5d51022a97a5b7358d0ea62bbbc00628c6cec06a
type commit
tag release/1.0.9
tagger NIIBE Yutaka <gniibe@fsij.org> 1542701768 +0900
Version 1.0.9.
gpg: Signature made Tue Nov 20 09:16:08 2018 CET
gpg: using EDDSA key 249CB3771750745D5CDD323CE267B052364F028D
gpg: issuer "gniibe@fsij.org"
gpg: Good signature from "NIIBE Yutaka <gniibe@fsij.org>" [unknown]
gpg: aka "NIIBE Yutaka <gniibe@debian.org>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg: There is no indication that the signature belongs to the owner.
Primary key fingerprint: 249C B377 1750 745D 5CDD 323C E267 B052 364F 028D
jas@kaka:~/src/neug$ cd ../gnuk/
jas@kaka:~/src/gnuk$ git checkout STABLE-BRANCH-1-2
Branch 'STABLE-BRANCH-1-2' set up to track remote branch 'STABLE-BRANCH-1-2' from 'origin'.
Switched to a new branch 'STABLE-BRANCH-1-2'
jas@kaka:~/src/gnuk$ git describe
release/1.2.20
jas@kaka:~/src/gnuk$ git tag -v `git describe`
object 9d3c08bd2beb73ce942b016d4328f0a596096c02
type commit
tag release/1.2.20
tagger NIIBE Yutaka <gniibe@fsij.org> 1650594032 +0900
Gnuk: Version 1.2.20
gpg: Signature made Fri Apr 22 04:20:32 2022 CEST
gpg: using EDDSA key 249CB3771750745D5CDD323CE267B052364F028D
gpg: Good signature from "NIIBE Yutaka <gniibe@fsij.org>" [unknown]
gpg: aka "NIIBE Yutaka <gniibe@debian.org>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg: There is no indication that the signature belongs to the owner.
Primary key fingerprint: 249C B377 1750 745D 5CDD 323C E267 B052 364F 028D
jas@kaka:~/src/gnuk/src$ git submodule update --init
Submodule 'chopstx' (https://salsa.debian.org/gnuk-team/chopstx/chopstx.git) registered for path '../chopstx'
Cloning into '/home/jas/src/gnuk/chopstx'...
Submodule path '../chopstx': checked out 'e12a7e0bb3f004c7bca41cfdb24c8b66daf3db89'
jas@kaka:~/src/gnuk$ cd chopstx
jas@kaka:~/src/gnuk/chopstx$ git describe
release/1.21
jas@kaka:~/src/gnuk/chopstx$ git tag -v `git describe`
object e12a7e0bb3f004c7bca41cfdb24c8b66daf3db89
type commit
tag release/1.21
tagger NIIBE Yutaka <gniibe@fsij.org> 1650593697 +0900
Chopstx: Version 1.21
gpg: Signature made Fri Apr 22 04:14:57 2022 CEST
gpg: using EDDSA key 249CB3771750745D5CDD323CE267B052364F028D
gpg: Good signature from "NIIBE Yutaka <gniibe@fsij.org>" [unknown]
gpg: aka "NIIBE Yutaka <gniibe@debian.org>" [unknown]
gpg: WARNING: This key is not certified with a trusted signature!
gpg: There is no indication that the signature belongs to the owner.
Primary key fingerprint: 249C B377 1750 745D 5CDD 323C E267 B052 364F 028D
jas@kaka:~/src/gnuk/chopstx$ cd ../src
jas@kaka:~/src/gnuk/src$ kdf_do=required ./configure --enable-factory-reset --vidpid=234b:0000 --target=FST_01SZ
Header file is: board-fst-01sz.h
Debug option disabled
Configured for bare system (no-DFU)
PIN pad option disabled
CERT.3 Data Object is NOT supported
Card insert/removal by HID device is NOT supported
Life cycle management is supported
Acknowledge button is supported
KDF DO is required before key import/generation
jas@kaka:~/src/gnuk/src$ make | less
jas@kaka:~/src/gnuk/src$ cd ../regnual/
jas@kaka:~/src/gnuk/regnual$ make | less
jas@kaka:~/src/gnuk/regnual$ cd ../../
jas@kaka:~/src$ sudo python3 neug/tool/neug_upgrade.py -f gnuk/regnual/regnual.bin gnuk/src/build/gnuk.bin
gnuk/regnual/regnual.bin: 4608
gnuk/src/build/gnuk.bin: 109568
CRC32: b93ca829
Device:
Configuration: 1
Interface: 1
20000e00:20005000
Downloading flash upgrade program...
start 20000e00
end 20002000
# 20002000: 32 : 4
Run flash upgrade program...
Wait 1 second...
Wait 1 second...
Device:
08001000:08020000
Downloading the program
start 08001000
end 0801ac00
jas@kaka:~/src$
The kernel log will contain the following, and the card is ready to use as an OpenPGP card. You may unplug it and re-insert it as you wish.
usb 3-3: reset full-speed USB device number 41 using xhci_hcd
usb 3-3: device firmware changed
usb 3-3: USB disconnect, device number 41
usb 3-3: new full-speed USB device number 42 using xhci_hcd
usb 3-3: New USB device found, idVendor=234b, idProduct=0000, bcdDevice= 2.00
usb 3-3: New USB device strings: Mfr=1, Product=2, SerialNumber=3
usb 3-3: Product: Gnuk Token
usb 3-3: Manufacturer: Free Software Initiative of Japan
usb 3-3: SerialNumber: FSIJ-1.2.20-42315277
Setting up the card is the next step, and there are many tutorials around for this, eventually I settled with the following sequence. Let’s start with setting the admin PIN. First make sure that pcscd nor scdaemon is running, which is good hygien since those processes cache some information and with a stale connection this easily leads to confusion. Cache invalidation… sigh.
jas@kaka:~$ gpg-connect-agent "SCD KILLSCD" "SCD BYE" /bye
jas@kaka:~$ ps auxww|grep -e pcsc -e scd
jas 30221 0.0 0.0 3468 1692 pts/3 R+ 11:49 0:00 grep --color=auto -e pcsc -e scd
jas@kaka:~$ gpg --card-edit
Reader ...........: 234B:0000:FSIJ-1.2.20-42315277:0
Application ID ...: D276000124010200FFFE423152770000
Application type .: OpenPGP
Version ..........: 2.0
Manufacturer .....: unmanaged S/N range
Serial number ....: 42315277
Name of cardholder: [not set]
Language prefs ...: [not set]
Salutation .......:
URL of public key : [not set]
Login data .......: [not set]
Signature PIN ....: forced
Key attributes ...: rsa2048 rsa2048 rsa2048
Max. PIN lengths .: 127 127 127
PIN retry counter : 3 3 3
Signature counter : 0
KDF setting ......: off
Signature key ....: [none]
Encryption key....: [none]
Authentication key: [none]
General key info..: [none]
gpg/card> admin
Admin commands are allowed
gpg/card> kdf-setup
gpg/card> passwd
gpg: OpenPGP card no. D276000124010200FFFE423152770000 detected
1 - change PIN
2 - unblock PIN
3 - change Admin PIN
4 - set the Reset Code
Q - quit
Your selection? 3
PIN changed.
1 - change PIN
2 - unblock PIN
3 - change Admin PIN
4 - set the Reset Code
Q - quit
Your selection?
Now it would be natural to setup the PIN and reset code. However the Gnuk software is configured to not allow this until the keys are imported. You would get the following somewhat cryptical error messages if you try. This took me a while to understand, since this is device-specific, and some other OpenPGP implementations allows you to configure a PIN and reset code before key import.
Your selection? 4
Error setting the Reset Code: Card error
1 - change PIN
2 - unblock PIN
3 - change Admin PIN
4 - set the Reset Code
Q - quit
Your selection? 1
Error changing the PIN: Conditions of use not satisfied
1 - change PIN
2 - unblock PIN
3 - change Admin PIN
4 - set the Reset Code
Q - quit
Your selection? q
Continue to configure the card and make it ready for key import. Some settings deserve comments. The lang field may be used to setup the language, but I have rarely seen it use, and I set it to ‘sv‘ (Swedish) mostly to be able to experiment if any software adhears to it. The URL is important to point to somewhere where your public key is stored, the fetch command of gpg --card-edit downloads it and sets up GnuPG with it when you are on a clean new laptop. The forcesig command changes the default so that a PIN code is not required for every digital signature operation, remember that I averaged 10 signatures per day for the past 2-3 years? Think of the wasted energy typing those PIN codes every time! Changing the cryptographic key type is required when I import 25519-based keys.
gpg/card> name
Cardholder's surname: Josefsson
Cardholder's given name: Simon
gpg/card> lang
Language preferences: sv
gpg/card> sex
Salutation (M = Mr., F = Ms., or space): m
gpg/card> login
Login data (account name): jas
gpg/card> url
URL to retrieve public key: https://josefsson.org/key-20190320.txt
gpg/card> forcesig
gpg/card> key-attr
Changing card key attribute for: Signature key
Please select what kind of key you want:
(1) RSA
(2) ECC
Your selection? 2
Please select which elliptic curve you want:
(1) Curve 25519
(4) NIST P-384
Your selection? 1
The card will now be re-configured to generate a key of type: ed25519
Note: There is no guarantee that the card supports the requested size.
If the key generation does not succeed, please check the
documentation of your card to see what sizes are allowed.
Changing card key attribute for: Encryption key
Please select what kind of key you want:
(1) RSA
(2) ECC
Your selection? 2
Please select which elliptic curve you want:
(1) Curve 25519
(4) NIST P-384
Your selection? 1
The card will now be re-configured to generate a key of type: cv25519
Changing card key attribute for: Authentication key
Please select what kind of key you want:
(1) RSA
(2) ECC
Your selection? 2
Please select which elliptic curve you want:
(1) Curve 25519
(4) NIST P-384
Your selection? 1
The card will now be re-configured to generate a key of type: ed25519
gpg/card>
Reader ...........: 234B:0000:FSIJ-1.2.20-42315277:0
Application ID ...: D276000124010200FFFE423152770000
Application type .: OpenPGP
Version ..........: 2.0
Manufacturer .....: unmanaged S/N range
Serial number ....: 42315277
Name of cardholder: Simon Josefsson
Language prefs ...: sv
Salutation .......: Mr.
URL of public key : https://josefsson.org/key-20190320.txt
Login data .......: jas
Signature PIN ....: not forced
Key attributes ...: ed25519 cv25519 ed25519
Max. PIN lengths .: 127 127 127
PIN retry counter : 3 3 3
Signature counter : 0
KDF setting ......: on
Signature key ....: [none]
Encryption key....: [none]
Authentication key: [none]
General key info..: [none]
gpg/card>
The device is now ready for key import! Bring out your offline laptop and boot it and use the keytocard command on the subkeys to import them. This assumes you saved a copy of the GnuPG home directory after generating the master and subkeys before, which I did in my own previous tutorial when I generated the keys. This may be a bit unusual, and there are simpler ways to do this (e.g., import a copy of the secret keys into a fresh GnuPG home directory).
$ cp -a gnupghome-backup-mastersubkeys gnupghome-import-fst01sz-42315277-2022-12-24
$ ps auxww|grep -e pcsc -e scd
$ gpg --homedir $PWD/gnupghome-import-fst01sz-42315277-2022-12-24 --edit-key B1D2BD1375BECB784CF4F8C4D73CF638C53C06BE
...
Secret key is available.
gpg: checking the trustdb
gpg: marginals needed: 3 completes needed: 1 trust model: pgp
gpg: depth: 0 valid: 1 signed: 0 trust: 0-, 0q, 0n, 0m, 0f, 1u
sec ed25519/D73CF638C53C06BE
created: 2019-03-20 expired: 2019-10-22 usage: SC
trust: ultimate validity: expired
ssb cv25519/02923D7EE76EBD60
created: 2019-03-20 expired: 2019-10-22 usage: E
ssb ed25519/80260EE8A9B92B2B
created: 2019-03-20 expired: 2019-10-22 usage: A
ssb ed25519/51722B08FE4745A2
created: 2019-03-20 expired: 2019-10-22 usage: S
[ expired] (1). Simon Josefsson <simon@josefsson.org>
gpg> key 1
sec ed25519/D73CF638C53C06BE
created: 2019-03-20 expired: 2019-10-22 usage: SC
trust: ultimate validity: expired
ssb* cv25519/02923D7EE76EBD60
created: 2019-03-20 expired: 2019-10-22 usage: E
ssb ed25519/80260EE8A9B92B2B
created: 2019-03-20 expired: 2019-10-22 usage: A
ssb ed25519/51722B08FE4745A2
created: 2019-03-20 expired: 2019-10-22 usage: S
[ expired] (1). Simon Josefsson <simon@josefsson.org>
gpg> keytocard
Please select where to store the key:
(2) Encryption key
Your selection? 2
sec ed25519/D73CF638C53C06BE
created: 2019-03-20 expired: 2019-10-22 usage: SC
trust: ultimate validity: expired
ssb* cv25519/02923D7EE76EBD60
created: 2019-03-20 expired: 2019-10-22 usage: E
ssb ed25519/80260EE8A9B92B2B
created: 2019-03-20 expired: 2019-10-22 usage: A
ssb ed25519/51722B08FE4745A2
created: 2019-03-20 expired: 2019-10-22 usage: S
[ expired] (1). Simon Josefsson <simon@josefsson.org>
gpg> key 1
sec ed25519/D73CF638C53C06BE
created: 2019-03-20 expired: 2019-10-22 usage: SC
trust: ultimate validity: expired
ssb cv25519/02923D7EE76EBD60
created: 2019-03-20 expired: 2019-10-22 usage: E
ssb ed25519/80260EE8A9B92B2B
created: 2019-03-20 expired: 2019-10-22 usage: A
ssb ed25519/51722B08FE4745A2
created: 2019-03-20 expired: 2019-10-22 usage: S
[ expired] (1). Simon Josefsson <simon@josefsson.org>
gpg> key 2
sec ed25519/D73CF638C53C06BE
created: 2019-03-20 expired: 2019-10-22 usage: SC
trust: ultimate validity: expired
ssb cv25519/02923D7EE76EBD60
created: 2019-03-20 expired: 2019-10-22 usage: E
ssb* ed25519/80260EE8A9B92B2B
created: 2019-03-20 expired: 2019-10-22 usage: A
ssb ed25519/51722B08FE4745A2
created: 2019-03-20 expired: 2019-10-22 usage: S
[ expired] (1). Simon Josefsson <simon@josefsson.org>
gpg> keytocard
Please select where to store the key:
(3) Authentication key
Your selection? 3
sec ed25519/D73CF638C53C06BE
created: 2019-03-20 expired: 2019-10-22 usage: SC
trust: ultimate validity: expired
ssb cv25519/02923D7EE76EBD60
created: 2019-03-20 expired: 2019-10-22 usage: E
ssb* ed25519/80260EE8A9B92B2B
created: 2019-03-20 expired: 2019-10-22 usage: A
ssb ed25519/51722B08FE4745A2
created: 2019-03-20 expired: 2019-10-22 usage: S
[ expired] (1). Simon Josefsson <simon@josefsson.org>
gpg> key 2
sec ed25519/D73CF638C53C06BE
created: 2019-03-20 expired: 2019-10-22 usage: SC
trust: ultimate validity: expired
ssb cv25519/02923D7EE76EBD60
created: 2019-03-20 expired: 2019-10-22 usage: E
ssb ed25519/80260EE8A9B92B2B
created: 2019-03-20 expired: 2019-10-22 usage: A
ssb ed25519/51722B08FE4745A2
created: 2019-03-20 expired: 2019-10-22 usage: S
[ expired] (1). Simon Josefsson <simon@josefsson.org>
gpg> key 3
sec ed25519/D73CF638C53C06BE
created: 2019-03-20 expired: 2019-10-22 usage: SC
trust: ultimate validity: expired
ssb cv25519/02923D7EE76EBD60
created: 2019-03-20 expired: 2019-10-22 usage: E
ssb ed25519/80260EE8A9B92B2B
created: 2019-03-20 expired: 2019-10-22 usage: A
ssb* ed25519/51722B08FE4745A2
created: 2019-03-20 expired: 2019-10-22 usage: S
[ expired] (1). Simon Josefsson <simon@josefsson.org>
gpg> keytocard
Please select where to store the key:
(1) Signature key
(3) Authentication key
Your selection? 1
sec ed25519/D73CF638C53C06BE
created: 2019-03-20 expired: 2019-10-22 usage: SC
trust: ultimate validity: expired
ssb cv25519/02923D7EE76EBD60
created: 2019-03-20 expired: 2019-10-22 usage: E
ssb ed25519/80260EE8A9B92B2B
created: 2019-03-20 expired: 2019-10-22 usage: A
ssb* ed25519/51722B08FE4745A2
created: 2019-03-20 expired: 2019-10-22 usage: S
[ expired] (1). Simon Josefsson <simon@josefsson.org>
gpg> quit
Save changes? (y/N) y
$
Now insert it into your daily laptop and have GnuPG and learn about the new private keys and forget about any earlier locally available card bindings — this usually manifests itself by GnuPG asking you to insert a OpenPGP card with another serial number. Earlier I did rm -rf ~/.gnupg/private-keys-v1.d/ but the scd serialno followed by learn --force is nicer. I also sets up trust setting for my own key.
jas@kaka:~$ gpg-connect-agent "scd serialno" "learn --force" /bye
...
jas@kaka:~$ echo "B1D2BD1375BECB784CF4F8C4D73CF638C53C06BE:6:" | gpg --import-ownertrust
jas@kaka:~$ gpg --card-status
Reader ...........: 234B:0000:FSIJ-1.2.20-42315277:0
Application ID ...: D276000124010200FFFE423152770000
Application type .: OpenPGP
Version ..........: 2.0
Manufacturer .....: unmanaged S/N range
Serial number ....: 42315277
Name of cardholder: Simon Josefsson
Language prefs ...: sv
Salutation .......: Mr.
URL of public key : https://josefsson.org/key-20190320.txt
Login data .......: jas
Signature PIN ....: not forced
Key attributes ...: ed25519 cv25519 ed25519
Max. PIN lengths .: 127 127 127
PIN retry counter : 5 5 5
Signature counter : 3
KDF setting ......: on
Signature key ....: A3CC 9C87 0B9D 310A BAD4 CF2F 5172 2B08 FE47 45A2
created ....: 2019-03-20 23:40:49
Encryption key....: A9EC 8F4D 7F1E 50ED 3DEF 49A9 0292 3D7E E76E BD60
created ....: 2019-03-20 23:40:26
Authentication key: CA7E 3716 4342 DF31 33DF 3497 8026 0EE8 A9B9 2B2B
created ....: 2019-03-20 23:40:37
General key info..: sub ed25519/51722B08FE4745A2 2019-03-20 Simon Josefsson <simon@josefsson.org>
sec# ed25519/D73CF638C53C06BE created: 2019-03-20 expires: 2023-09-19
ssb> ed25519/80260EE8A9B92B2B created: 2019-03-20 expires: 2023-09-19
card-no: FFFE 42315277
ssb> ed25519/51722B08FE4745A2 created: 2019-03-20 expires: 2023-09-19
card-no: FFFE 42315277
ssb> cv25519/02923D7EE76EBD60 created: 2019-03-20 expires: 2023-09-19
card-no: FFFE 42315277
jas@kaka:~$
Verify that you can digitally sign and authenticate using the key and you are done!
jas@kaka:~$ echo foo|gpg -a --sign|gpg --verify
gpg: Signature made Sat Dec 24 13:49:59 2022 CET
gpg: using EDDSA key A3CC9C870B9D310ABAD4CF2F51722B08FE4745A2
gpg: Good signature from "Simon Josefsson <simon@josefsson.org>" [ultimate]
jas@kaka:~$ ssh-add -L
ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAILzCFcHHrKzVSPDDarZPYqn89H5TPaxwcORgRg+4DagE cardno:FFFE42315277
jas@kaka:~$
So time to relax and celebrate christmas? Hold on… not so fast! Astute readers will have noticed that the output said ‘PIN retry counter: 5 5 5‘. That’s not the default PIN retry counter for Gnuk! How did that happen? Indeed, good catch and great question, my dear reader. I wanted to include how you can modify the Gnuk source code, re-build it and re-flash the Gnuk as well. This method is different than flashing Gnuk onto a device that is running NeuG so the commands I used to flash the firmware in the start of this blog post no longer works in a device running Gnuk. Fortunately modern Gnuk supports updating firmware by specifying the Admin PIN code only, and provides a simple script to achieve this as well. The PIN retry counter setting is hard coded in the openpgp-do.c file, and we run a a perl command to modify the file, rebuild Gnuk and upgrade the FST-01SZ. This of course wipes all your settings, so you will have the opportunity to practice all the commands earlier in this post once again!
jas@kaka:~/src/gnuk/src$ perl -pi -e 's/PASSWORD_ERRORS_MAX 3/PASSWORD_ERRORS_MAX 5/' openpgp-do.c
jas@kaka:~/src/gnuk/src$ make | less
jas@kaka:~/src/gnuk/src$ cd ../tool/
jas@kaka:~/src/gnuk/tool$ ./upgrade_by_passwd.py
Admin password:
Device:
Configuration: 1
Interface: 0
../regnual/regnual.bin: 4608
../src/build/gnuk.bin: 110592
CRC32: b93ca829
Device:
Configuration: 1
Interface: 0
20002a00:20005000
Downloading flash upgrade program...
start 20002a00
end 20003c00
Run flash upgrade program...
Waiting for device to appear:
Wait 1 second...
Wait 1 second...
Device:
08001000:08020000
Downloading the program
start 08001000
end 0801b000
Protecting device
Finish flashing
Resetting device
Update procedure finished
jas@kaka:~/src/gnuk/tool$
Now finally, I wish you all a Merry Christmas and Happy Hacking!
