[She] came round to me and put her arm around my waist and said under her breath, "Hey, she can be taught," with a tease in her voice that wobbled a little, and when I looked at her, her eyes were bright and wet, and I put my arm around her shoulders and hugged her.

probe_duration_seconds instance="example.net:5222",job="blackbox",module="xmpp_banner"  = 0.01
probe_duration_seconds instance="example.net:5269",job="blackbox",module="xmpp_banner"  = 0.01

Perl REGEX Problems courtesy of XKCD

label_replace(probe_duration_seconds module="xmpp_banner" , "port", "$1", "instance", ".*:(.*)")
probe_duration_seconds instance="example.net:5222",job="blackbox",module="xmpp_banner",port="5222" 	0.001
probe_duration_seconds instance="example.net:5269",job="blackbox",module="xmpp_banner",port="5269" 	0.002

1. Evaluate value, which is generally some sort of query such as probe_duration_seconds
2. Find the required source label src_label, in this example is instance, in this case the values are example.net:5222 and example.net:5269
3. Apply regular expression regex, for us its .*:(.*) That says skip everying before : then capture/store everything past : . The brackets mean copy what is after the colon and put it in match #1
4. Make a new label specified in dst_label, for us this is port
5. Whatever is in replacement goes into dst_label. For this example it is $1 which means match #1 in our regular expression in the label called port.

Grafana console showing the use of the label_replace function

Inter-canister calls The Internet Computer system provides inter-canister communication that follows the actor model: Inter-canister calls are implemented via two asynchronous messages, one to initiate the call, and one to return the response. Canisters process messages atomically (and roll back upon certain error conditions), but not complete calls. This makes programming with inter-canister calls error-prone. Possible common sources for bugs, vulnerabilities or simply unexpected behavior are:

• Reading global state before issuing an inter-canister call, and assuming it to still hold when the call comes back.
• Changing global state before issuing an inter-canister call, changing it again in the response handler, but assuming nothing else changes the state in between (reentrancy).
• Changing global state before issuing an inter-canister call, and not handling failures correctly, e.g. when the code handling the callback rolls backs.

If you find such pattern in your code, you should analyze if a malicious party can trigger them, and assess the severity that effect These issues apply to all canisters, and are not Motoko-specific.

Rollbacks Even in the absence of inter-canister calls the behavior of rollbacks can be surprising. In particular, rejecting (i.e. throw) does not rollback state changes done before, while trapping (e.g. Debug.trap, assert , out of cycle conditions) does. Therefore, one should check all public update call entry points for unwanted state changes or unwanted rollbacks. In particular, look for methods (or rather, messages, i.e. the code between commit points) where a state change is followed by a throw. This issues apply to all canisters, and are not Motoko-specific, although other CDKs may not turn exceptions into rejects (which don t roll back).

Talking to malicious canisters Talking to untrustworthy canisters can be risky, for the following (likely incomplete) reasons:

• The other canister can withhold a response. Although the bidirectional messaging paradigm of the Internet Computer was designed to guarantee a response eventually, the other party can busy-loop for as long as they are willing to pay for before responding. Worse, there are ways to deadlock a canister.
• The other canister can respond with invalidly encoded Candid. This will cause a Motoko-implemented canister to trap in the reply handler, with no easy way to recover. Other CDKs may give you better ways to handle invalid Candid, but even then you will have to worry about Candid cycle bombs that will cause your reply handler to trap.

Many canisters do not even do inter-canister calls, or only call other trustwothy canisters. For the others, the impact of this needs to be carefully assessed.

Canister upgrade: overview For most services it is crucial that canisters can be upgraded reliably. This can be broken down into the following aspects:

1. Can the canister be upgraded at all?
2. Will the canister upgrade retain all data?
3. Can the canister be upgraded promptly?
4. Is three a recovery plan for when upgrading is not possible?

Canister upgradeability A canister that traps, for whatever reason, in its canister_preupgrade system method is no longer upgradeable. This is a major risk. The canister_preupgrade method of a Motoko canister consists of the developer-written code in any system func preupgrade() block, followed by the system-generated code that serializes the content of any stable var into a binary format, and then copies that to stable memory. Since the Motoko-internal serialization code will first serialize into a scratch space in the main heap, and then copy that to stable memory, canisters with more than 2GB of live data will likely be unupgradeable. But this is unlikely the first limit: The system imposes an instruction limit on upgrading a canister (spanning both canister_preupgrade and canister_postupgrade). This limit is a subnet configuration value, and sepearate (and likely higher) than the normal per-message limit, and not easily determined. If the canister s live data becomes too large to be serialized within this limit, the canister becomes non-upgradeable. This risk cannot be eliminated completely, as long as Motoko and Stable Variables are used. It can be mitigated by appropriate load testing: Install a canister, fill it up with live data, and exercise the upgrade. If this succeeds with a live data set exceeding the expected amount of data by a margin, this risk is probably acceptable. Bonus points for adding functionality that will prevent the canister s live data to increase above a certain size. If this testing is to be done on a local replica, extra care needs to be taken to make sure the local replica actually performs instruction counting and has the same resource limits as the production subnet. An alternative mitigation is to avoid canister_pre_upgrade as much as possible. This means no use of stable var (or restricted to small, fixed-size configuration data). All other data could be

• mirrored off the canister (possibly off chain), and manually re-hydrated after an upgrade.
• stored in stable memory manually, during each update call, using the ExperimentalStableMemory API. While this matches what high-assurance Rust canisters (e.g. the Internet Identity) do, This requires manual binary encoding of the data, and is marked experimental, so I cannot recommend this at the moment.
• not put into a Motoko canister until Motoko has a scalable solution for stable variable (for example keeping them in stable memory permanently, with smart caching in main memory, and thus obliterating the need for pre-upgrade code.)

Data retention on upgrades Obviously, all live data ought to be retained during upgrades. Motoko automatically ensures this for stable var data. But often canisters want to work with their data in a different format (e.g. in objects that are not shared and thus cannot be put in stable vars, such as HashMap or Buffer objects), and thus may follow following idiom:

stable var fooStable =  ;
var foo = fooFromStable(fooStable);
system func preupgrade()   fooStable := fooToStable(foo);  )
system func postupgrade()   fooStable := (empty);  )

In this case, it is important to check that

• All non-stable global vars, or global lets with mutable values, have a stable companion.
• The assignments to foo and fooStable are not forgotten.
• The fooToStable and fooFromStable form bijections.

An example would be HashMaps stored as arrays via Iter.toArray( .entries()) and HashMap.fromIter( .vals()). It is worth pointiong out that a code view will only look at a single version of the code, but cannot check whether code changes will preserve data on upgrade. This can easily go wrong if the names and types of stable variables are changed in incompatible way. The upgrade may fail loudly in this cases, but in bad cases, the upgrade may even succeed, losing data along the way. This risk needs to be mitigated by thorough testing, and possibly backups (see below).

Prompt upgrades Motoko and Rust canisters cannot be safely upgraded when they are still waiting for responses to inter-canister calls (the callback would eventually reach the new instance, and because of infelicities of the IC s System API, could possibly call arbitrary internal functions). Therefore, the canister needs to be stopped before upgrading, and started again. If the inter-canister calls take a long time, this mean that upgrading may take a long time, which may be undesirable. Again, this risk is reduced if all calls are made to trustworthy canisters, and elevated when possibly untrustworthy canisters are called, directly or indirectly.

Backup and recovery Because of the above risk around upgrades it is advisable to have a disaster recovery strategy. This could involve off-chain backups of all relevant data, so that it is possible to reinstall (not upgrade) the canister and re-upload all data. Note that reinstall has the same issue as upgrade described above in prompt upgrades : It ought to be stopped first to be safe. Note that the instruction limit for messages, as well as the message size limit, limit the amount of data returned. If the canister needs to hold more data than that, the backup query method might have to return chunks or deltas, with all the extra complexity that entails, e.g. state changes between downloading chunks. If large data load testing is performed (as Irecommend anyways to test upgradeability), one can test whether the backup query method works within the resource limits.

Time is not strictly monotonic The timestamps for current time that the Internet Computer provides to its canisters is guaranteed to be monotonic, but not strictly monotonic. It can return the same values, even in the same messages, as long as they are processed in the same block. It should therefore not be used to detect happens-before relations. Instead of using and comparing time stamps to check whether Y has been performed after X happened last, introduce an explicit var y_done : Bool state, which is set to False by X and then to True by Y. When things become more complex, it will be easier to model that state via an enumeration with speaking tag names, and update this state machine along the way. Another solution to this problem is to introduce a var v : Nat counter that you bump in every update method, and after each await. Now v is your canister s state counter, and can be used like a timestamp in many ways. While we are talking about time: The system time (typically) changes across an await. So if you do let now = Time.now() and then await, the value in now may no longer be what you want.

Wrapping arithmetic The Nat64 data type, and the other fixed-width numeric types provide opt-in wrapping arithmetic (e.g. +%, fromIntWrap). Unless explicitly required by the current application, this should be avoided, as usually a too large or negatie value is a serious, unrecoverable logic error, and trapping is the best one can do.

Cycle balance drain attacks Because of the IC s canister pays model, all canisters are prone to DoS attacks by draining their cycle balance, and this risk needs to be taken into account. The most elementary mitigation strategy is to monitor the cycle balance of canisters and keep it far from the (configurable) freezing threshold. On the raw IC-level, further mitigation strategies are possible:

• If all update calls are authenticated, perform this authentication as quickly as possible, possibly before decoding the caller s argument. This way, a cycle drain attack by an unauthenticated attacker is less effective (but still possible).
• Additionally, implementing the canister_inspect_message system method allows the above checks to be performed before the message even is accepted by the Internet Computer. But it does not defend against inter-canister messages and is therefore not a complete solution.
• If an attack from an authenticated user (e.g. a stakeholder) is to be expected, the above methods are not effective, and an effective defense might require relatively involved additional program logic (e.g. per-caller statistics) to detect such an attack, and react (e.g. rate-limiting).
• Such defenses are pointless if there is only a single method where they do not apply (e.g. an unauthenticated user registration method). If the application is inherently attackable this way, it is not worth the bother to raise defenses for other methods.

Related: A justification why the Internet Identity does not use canister_inspect_message) A motoko-implemented canister currently cannot perform most of these defenses: Argument decoding happens unconditionally before any user code that may reject a message based on the caller, and canister_inspect_message is not supported. Furthermore, Candid decoding is not very cycle defensive, and one should assume that it is possible to construct Candid messages that require many instructions to decode, even for simple argument type signatures. The conclusion for the audited canisters is to rely on monitoring to keep the cycle blance up, even during an attack, if the expense can be born, and maybe pray for IC-level DoS protections to kick in.

Large data attacks Another DoS attack vector exists if public methods allow untrustworthy users to send data of unlimited size that is persisted in the canister memory. Because of the translation of async-await code into multiple message handlers, this applies not only to data that is obviously stored in global state, but also local data that is live across an await point. The effectiveness of such attacks is limited by the Internet Computer s message size limit, which is in the order of a few megabytes, but many of those also add up. The problem becomes much worse if a method has an argument type that allows a Candid space bomb: It is possible to encode very large vectors with all values null in Candid, so if any method has an argument of type [Null] or [?t], a small message will expand to a large value in the Motoko heap. Other types to watch out:

• Nat and Int: This is an unbounded natural number, and thus can be arbitrarily large. The Motoko representation will however not be much larger than the Candid encoding (so this does not qualify as a space bomb).

It is still advisable to check if the number is reasonable in size before storing it or doing an await. For example, when it denotes an index in an array, throw early if it exceeds the size of the array; if it denotes a token amount to transfer, check it against the available balance, if it denotes time, check it against reasonable bounds.

• Principal: A Principal is effectively a Blob. The Interface specification says that principals are at most 29 bytes in length, but the Motoko Candid decoder does not check that currently (fixed in the next version of Motoko). Until then, a Principal passed as an argument can be large (the principal in msg.caller is system-provided and thus safe). If you cannot wait for the fix to reach you, manually check the size of the princial (via Principal.toBlob) before doing the await.

Shadowing of msg or caller Don t use the same name for the message context of the enclosing actor and the methods of the canister: It is dangerous to write shared(msg) actor, because now msg is in scope across all public methods. As long as these also use public shared(msg) func , and thus shadow the outer msg, it is correct, but it if one accidentially omits or mis-types the msg, no compiler error would occur, but suddenly msg.caller would now be the original controller, likely defeating an important authorization step. Instead, write shared(init_msg) actor or shared( caller = controller ) actor to avoid using msg.

Conclusion If you write a serious canister, whether in Motoko or not, it is worth to go through the code and watch out for these patterns. Or better, have someone else review your code, as it may be hard to spot issues in your own code. Unfortunately, such a list is never complete, and there are surely more ways to screw up your code in addition to all the non-IC-specific ways in which code can be wrong. Still, things get done out there, so best of luck!

• Reworked the dense stereo processing. This is now documented, with nice APIs. Rectified models can be represented in a .cameramodel file, and saved to disk.
• Added sparse triangulation routines. Uncertainty can be propagated through these routines to gauge the effects of calibration-time and observation-time noise.
• LENSMODEL_SPLINED_STEREOGRAPHIC models have been thoroughly tested, and are ready for prime time. Solver now applies anisotropic regularization to reduce curl in the correction vector field, so the solved models now act mostly radially. The mrcal-show-splined-model-correction tool extended, and produces clearer plots. These models work well. Use them.
• The observed_pixel_uncertainty is now estimated from the optimized residuals instead of being specified explicitly. The reported uncertainties should now be correct in absolute, not just relative terms
• mrcal.unproject() can report gradients
• Calibration residuals can be visualized from the stored cameramodel, not just from mrcal-calibrate-cameras --explore. Added new tools
  • mrcal-show-residuals-board-observation
  • mrcal-show-residuals
  and new Python API functions
  • mrcal.show_residuals_board_observation()
  • mrcal.show_residuals_histogram()
  • mrcal.show_residuals_vectorfield()
  • mrcal.show_residuals_magnitudes()
  • mrcal.show_residuals_directions()
  • mrcal.show_residuals_regional()
• .cameramodel files can be read/written from C
• Added simple projection/unprojection functions to the Python and C APIs:
  • mrcal.project_pinhole()
  • mrcal.unproject_pinhole()
  • mrcal.project_latlon()
  • mrcal.unproject_latlon()
  • mrcal.project_lonlat()
  • mrcal.unproject_lonlat()
  This is added to the existing functions
  • mrcal.project_stereographic()
  • mrcal.unproject_stereographic()
• Added LENSMODEL_LATLON and LENSMODEL_LONLAT models to represent epipolar-aligned and panoramic images respectively

• Thin provisioned full and incremental backups.
• Compression (lz4).
• Freezing the virtual machine guest fs via qemu-agent (if installed)
• Multithreaded backup, if multiple disks are attached.
• Point in time recovery to a given incremental backup.
• Includes nbdkit plugin and utility that allows to map the thin provisioned backup images to a block device, for single file or instant recovery (boot the virtual machine directly from the backup image)

 <domain type='kvm' id='1' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'>
 [..]
 <qemu:capabilities>
   <qemu:add capability='incremental-backup'/>
 </qemu:capabilities>
 [..]
 </domain>

# virtnbdbackup -d vm2 -l full -o /tmp/WEEKLY_BACKUP/
 [..]
[2021-11-08 15:43:46] INFO virtnbdbackup - main [MainThread]: Backup jobs finished, stopping backup task.
[2021-11-08 15:43:46] INFO virtnbdbackup - main [MainThread]: Finished
# tree /tmp/WEEKLY_BACKUP/
 /tmp/WEEKLY_BACKUP/
  backup.full.11082021154343.log
  checkpoints
    virtnbdbackup.0.xml
  sda.full.data
  vm2.cpt
  vmconfig.virtnbdbackup.0.xml

 # virtnbdbackup -d vm2 -l inc -o /tmp/WEEKLY_BACKUP/
 # tree /tmp/WEEKLY_BACKUP/
 /tmp/WEEKLY_BACKUP/
  backup.full.11082021154343.log
  backup.inc.11082021154538.log
  checkpoints
    virtnbdbackup.0.xml
    virtnbdbackup.1.xml
  sda.full.data
  sda.inc.virtnbdbackup.1.data
  vm2.cpt
  vmconfig.virtnbdbackup.0.xml
  vmconfig.virtnbdbackup.1.xml

 # virtnbdrestore -a restore -i /tmp/WEEKLY_BACKUP/ -o /tmp/VM_RESTORE

# virtnbdmap -f /tmp/WEEKLY_BACKUP/sda.full.data
 [..] INFO virtnbdmap - <module> [MainThread]: Done mapping backup image to [/dev/nbd0]
 [..] INFO virtnbdmap - <module> [MainThread]: Press CTRL+C to disconnect
# fdisk -l /dev/nbd0
Disk /dev/nbd0: 2 GiB, 2147483648 bytes, 4194304 sectors

qemu-img create -b /dev/nbd0 -f qcow2 bootme.qcow2
qemu-system-x86_64 -enable-kvm -m 2000 -hda bootme.qcow2

Welcome to the October 2021 report from the Reproducible Builds project!
This month Samanta Navarro posted to the oss-security security mailing on a novel category of exploit in the .tar archive format, where a single .tar file contains different contents depending on the tar utility being used. Naturally, this has consequences for reproducible builds as Samanta goes onto reply:

Arch Linux uses libarchive (bsdtar) in its build environment. The default tar program installed is GNU tar. It is possible to create a source distribution which leads to different files seen by the build environment than compared to a careful reviewer and other Linux distributions.

I have submitted bug reports and patches to some projects but eventually I had to conclude that the problem itself cannot be fixed by these implementations alone. The best choice for these tools would be to only allow archives which are fully compatible to standards but this in turn would render a lot of archives broken.

Reproducibility, repeatability and traceability of builds, drawing heavily on best-practices championed by the Reproducible Builds project.

I got a PR in my repository a few days ago leading back to a team trying to make it easier for packages to be reproducible from source.

Events and presentations

• PackagingCon is a conference for developers of package management software, their communities and other stakeholders. This virtual event, which will take place on the 9th and 10th November 2021, has a mission is to bring different ecosystems together . The schedule for the event is now available to view online.
• The Linux Foundation s OpenSSF group announced that the next OpenSSF quarterly town hall will take place on 15th November 2021. Registration is now open.

• Last month, Wolfgang Mauerer gave a presentation at the MiniDebConf 2021 Regensburg about the Civil Infrastructure Platform that covered many subjects including Reproducible Builds. PDF slides of the talk are available, as is a video recording.
• In addition, Trevor Rosen from SolarWinds presented at the Linux Foundation s Supply Chain Security Con last month on incorporating in-toto into their build system. in-toto a framework to secure the integrity of software supply chains. Trevor also discusses building everything twice to validate the first build la reproducible builds. (PDF slides)
• Lastly, Mattia Rizzolo posted an update on the next Reproducible Builds in-person event to our mailing list: currently we are thinking ahead to 2022 .

Community news On our mailing list this month:

• Jeremiah announced the release of version 1.4 of stage0-posix, part of a broader effort to provide an ultra-minimal bootstrap seed to increase trust in our software stack.
• Chris Lamb mentioned that Azure are offering free compute power for open source projects which might be useful for one of the many rebuilder projects .
• kpcyrd announced the release of rebuilderd v0.15.0, but also linked to a Twitter thread that contains intro on how rebuilderd works and a walk-through on how to write custom integrations.
• Fredrik Str mberg offered an update on the Sigsum project and some specific milestones within transparency logging efforts: after a year of design iterations we have not only designed a transparency log but also decided to turn it into a project of its own .

There were quite a few changes to the Reproducible Builds website and documentation this month as well, including Feng Chai updating some links on our publications page [ ] and marco updated our project metadata around the Bitcoin Core building guide [ ].
Lastly, we ran another productive meeting on IRC during October. A full set of notes from the meeting is available to view.

Distribution work Qubes was heavily featured in the latest edition of Linux Weekly News, and a significant section was dedicated to discussing reproducibility. For example, it was mentioned that the Qubes project has been working on incorporating reproducible builds into its continuous integration (CI) infrastructure . But the LWN article goes on to describe that:

The current goal is to be able to build the Qubes OS Debian templates solely from packages that can be built reproducibly. Templates in Qubes OS are VM images that can be used to start an application qube quickly based on the template. The qube will have read-only access to the root filesystem of the template, so that the same root filesystem can be shared with multiple application qubes. There are official templates for several variants of both Fedora and Debian, as well as community maintained templates for several other distributions.

You can view the whole article on LWN, and Fr d ric also published a lengthy summary about their work on reproducible builds in Qubes as well for those wishing to learn more.
In Debian this month, 133 reviews of Debian packages were added, 81 were updated and 24 were removed this month, adding to Debian s ever-growing knowledge about identified issues. A number of issues were categorised and added by Chris Lamb and Vagrant Cascadian too [ ][ ][ ]. In addition, work on alternative snapshot service has made progress by Fr d ric Pierret and Holger Levsen this month, including moving from the existing host (snapshot.notset.fr) to snapshot.reproducible-builds.org (more info) thanks to OSUOSL for the machine and hosting and Debian for the disks.
Finally, Bernhard M. Wiedemann posted his monthly reproducible builds status report.

diffoscope diffoscope is our in-depth and content-aware diff utility. Not only can it locate and diagnose reproducibility issues, it can provide human-readable diffs from many kinds of binary formats. This month, Chris Lamb made the following changes, including preparing and uploading versions 186, 187, 188 and 189 to Debian

• New features:
  • Add support for Python Sphinx inventory files (usually named objects.inv on-disk). [ ]
  • Add support for comparing .pyc files. Thanks to Sergei Trofimovich for the inspiration. [ ]
  • Try some alternative suffixes (e.g. .py) to support distributions that strip or retain them. [ ][ ]
• Bug fixes:
  • Fix Python decompilation tests under Python 3.10+ [ ] and for Python 3.7 [ ].
  • Don t raise a traceback if we cannot unmarshal Python bytecode. This is in order to support Python 3.7 failing to load .pyc files generated with newer versions of Python. [ ]
  • Skip Python bytecode testing where we do not have an expected diff. [ ]
• Codebase improvements:
  • Use our file_version_is_lt utility instead of accepting both versions of uImage expected diff. [ ]
  • Split out a custom call to assert_diff for a .startswith equivalent. [ ]
  • Use skipif instead of manual conditionals in some tests. [ ]

In addition, Jelle van der Waa added external tool references for Arch Linux for ocamlobjinfo, openssl and ffmpeg [ ][ ][ ] and added Arch Linux as a Continuous Integration (CI) test target. [ ] and Vagrant Cascadian updated the testsuite to skip Python bytecode comparisons when file(1) is older than 5.39. [ ] as well as added external tool references for the Guix distribution for dumppdf and ppudump. [ ][ ]. Vagrant Cascadian also updated the diffoscope package in GNU Guix [ ][ ]. Lastly, Guangyuan Yang updated the FreeBSD package name on the website [ ], Mattia Rizzolo made a change to override a new Lintian warning due to the new test files [ ], Roland Clobus added support to detect and log if the GNU_BUILD_ID field in an ELF binary been modified [ ], Sandro J ckel updated a number of helpful links on the website [ ] and Sergei Trofimovich made the uImage test output support file() version 5.41 [ ].

reprotest reprotest is the Reproducible Build s project end-user tool to build same source code twice in widely differing environments, checking the binaries produced by the builds for any differences. This month, reprotest version 0.7.18 was uploaded to Debian unstable by Holger Levsen, which also included a change by Holger to clarify that Python 3.9 is used nowadays [ ], but it also included two changes by Vasyl Gello to implement realistic CPU architecture shuffling [ ] and to log the selected variations when the verbosity is configured at a sufficiently high level [ ]. Finally, Vagrant Cascadian updated reprotest to version 0.7.18 in GNU Guix.

Upstream patches The Reproducible Builds project detects, dissects and attempts to fix unreproducible packages. We try to send all of our patches upstream where appropriate. We authored a large number of such patches this month, including:

• Bernhard M. Wiedemann:
  • gtk4 (date-related issue)
  • ipxe (version upgrade)
  • libsoup2 (build failure in the future)
  • pari (parallelism-related issue)
• Chris Lamb:
  • #901307 filed against sphinx-gallery (re-opened with extensive updates).
  • #995809 filed against libinput.
  • #995865 filed against python-pipx.
  • #996200 filed against node-inquirer.
  • #996674 filed against libminidns-java.
  • #996834 filed against pytools.
  • #996881 filed against pikepdf.
  • #996948 filed against sphinx (forwarded upstream)
  • #996999 filed against fenics-basix.
  • #997000 filed against snakemake.
  • #997689 filed against smplayer.
  • #997949 filed against python-duniterpy.
  • #998104 filed against afnix.
  • #998059 filed against sphinx (forwarded upstream).
• Vagrant Cascadian:
  • #977684 filed against mahimahi (filed upstream).
  • #985187 filed against ffmpeg (forwarded upstream)
  • #995646 filed against abntex.
  • #995647 filed against cfi.
  • #995648 filed against cffi.
  • #995650 filed against chktex.
  • #995651 filed against fdutils.
  • #995652 filed against gnu-standards.
  • #995654 filed against malaga.
  • #995741 filed against latex-mk.
  • #995745 filed against kannel.
  • #995747 filed against xnee.
  • #995886, #995896, #995953 & #995954 filed against cxref.
  • #995960 filed against xnee.
  • #996184 filed against binutils-or1k-elf.
  • #996194 & #996572 filed against gcc-arm-none-eabi.
  • #996599 filed against xdmf.
  • #996679 filed against flightgear.
  • #997036 & #997037 filed against kvirc.

Testing framework The Reproducible Builds project runs a testing framework at tests.reproducible-builds.org, to check packages and other artifacts for reproducibility. This month, the following changes were made:

• Holger Levsen:
  • Debian-related changes:
    • Incorporate a fix from bremner into builtin-pho related to binary-NMUs. [ ]
    • Keep bullseye environments around longer, in an attempt to fix a Jenkins issue. [ ]
    • Improve the documentation of buildinfos.debian.net. [ ]
    • Improve documentation for the builtin-pho setup. [ ][ ]
  • OpenWrt-related changes:
    • Also use -j1 for better debugging. [ ]
    • Document that that Python 3.x is now used. [ ]
    • Enable further debugging for the toolchain build. [ ]
  • New snapshot.reproducible-builds.org service:
    • Actually add new node. [ ][ ]
    • Install xfsprogs on snapshot.reproducible-builds.org. [ ]
    • Create account for fpierret on new node. [ ]
    • Run node_health_check job on new node too. [ ]
• Mattia Rizzolo:
  • Debian-related changes:
    • Handle schroot errors when invoking diffoscope instead of masking them. [ ][ ]
    • Declare and define some variables separately to avoid masking the subshell return code. [ ]
    • Fix variable name. [ ]
    • Improve log reporting. [ ]
    • Execute apt-get update with the -q argument to get more decent logs. [ ]
    • Set the Debian HTTP mirror and proxy for snapshot.reproducible-builds.org. [ ]
    • Install the libarchive-tools package (instead of bsdtar) when updating Jenkins nodes. [ ]
  • Be stricter about errors when starting the node agent [ ] and don t overwrite NODE_NAME so that we can expect Jenkins to properly set for us [ ].
  • Explicitly warn if the NODE_NAME is not a fully-qualified domain name (FQDN). [ ]
  • Document whether a node runs in the future. [ ]
  • Disable postgresql_autodoc as it not available in bullseye. [ ]
  • Don t be so eager when deleting schroot internals, call to schroot -e to terminate the schroots instead. [ ]
  • Only consider schroot underlays for deletion that are over a month old. [ ][ ]
  • Only try to unmount /proc if it s actually mounted. [ ]
  • Move the db_backup task to its own Jenkins job. [ ]

Lastly, Vasyl Gello added usage information to the reproducible_build.sh script [ ].

Contributing If you are interested in contributing to the Reproducible Builds project, please visit our Contribute page on our website. However, you can get in touch with us via:

• IRC: #reproducible-builds on irc.oftc.net.
• Twitter: @ReproBuilds
• Mailing list: rb-general@lists.reproducible-builds.org

$ ssh web04
$ rsync -e 'sh -c ">&2 echo $@" echo' -aLv /data/. web05:/data/.
web05 rsync --server -vlogDtpre.iLsfxCIvu . /data/.
rsync: connection unexpectedly closed (0 bytes received so far) [sender]
rsync error: error in rsync protocol data stream (code 12) at io.c(228) [sender=3.2.3]

$ ssh -L 127.0.0.1:5000:127.0.0.1:5000 web05
$ socat tcp-listen:5000,reuseaddr exec:"rsync --server -vlogDtpre.iLsfxCIvu . /data/."

$ ssh -R 127.0.0.1:5000:127.0.0.1:5000 web04
$ rsync -e 'sh -c "socat stdio tcp-connect:127.0.0.1:5000"' -aLv /data/. remote:/data/.
sending incremental file list
haproxy.debian.net/
haproxy.debian.net/dists/buster-backports-1.8/Contents-amd64.bz2
haproxy.debian.net/dists/buster-backports-1.8/Contents-i386.bz2
[ ]
media.luffy.cx/videos/2021-frnog34-jerikan/progressive.mp4
sent 921,719,453 bytes  received 26,939 bytes  7,229,383.47 bytes/sec
total size is 7,526,872,300  speedup is 8.17

How each process is connected together. Arrows labeled stdio are implemented as two pipes connecting the process to the left to the standard input and output of the process to the right. Don't be fooled by the apparent symmetry!

The options --server and --sender are used internally by rsync, and should never be typed by a user under normal circumstances. Some awareness of these options may be needed in certain scenarios, such as when setting up a login that can only run an rsync command. For instance, the support directory of the rsync distribution has an example script named rrsync (for restricted rsync) that can be used with a restricted ssh login.

Addendum I was hoping to get something similar with a one-liner. But this does not work!

$ socat \
>  exec:"ssh web04 rsync --server --sender -vlLogDtpre.iLsfxCIvu . /data/." \
>  exec:"ssh web05 rsync --server -vlogDtpre.iLsfxCIvu /data/. /data/." \
over-long vstring received (511 > 255)
over-long vstring received (511 > 255)
rsync error: requested action not supported (code 4) at compat.c(387) [sender=3.2.3]
rsync error: requested action not supported (code 4) at compat.c(387) [Receiver=3.2.3]
socat[878291] E waitpid(): child 878292 exited with status 4
socat[878291] E waitpid(): child 878293 exited with status 4

---

1. And SSH agent forwarding is dangerous. Don t use it if you can.

1. Some kind of 45 leaning prong to dry bottles and flasks on
2. A tea tray and coasters
3. a replacement prop arm/foot for my computer keyboard (something like this but for the Lenovo Ultranav)
4. some attempted representation of Borges Library of Babel, a la @jwz The Library of Babel, again
5. an exploration of the geometry of Susanna Clarke s Piranesi
6. further iterations of my castle
7. Small tins to keep loose-leaf tea in
8. Who am I kidding, bound to be a map from DOOM. E1M1 perhaps, or something more regular (MAP07? E2M8?) See also this amazing print of Quake 3: Arena's "Camping Grounds"
9. replacement bits for kids toy sets, e.g. a bolt with long shank from Early Learning Centre Build It Deluxe Set, without all 4 of which you can't build much of anything
10. A stand for a decorative Christmas bauble (kid's hand print on it) A roll of cellotape works pretty well in the mean time
11. DIY bits-and-bobs sorter/storage (nuts and bolts etc)
12. A space ship from Elite/Frontier. Probably a Cobra mk3 or maybe a Viper mk2. In a glow-in-the-dark PLA which i d overpaint with gunmetal except for the fuselage
13. A watch stand/holder/storage thing Except it would look nicer in wood (And I m more inclined to get rid of all but one watch instead)
14. Little tabbed 7 dividers for vinyl records, with A-Z cut into the tabs 12 ones might be a stretch (something like this)
15. A low-profile custom trackpoint cover like the ones by SaotoTech (e.g.)
16. A vinyl record. (Not sure that any 3D printer I would have access to would have the necessary resolution. I haven't done any research yet.)
17. A free-standing inclined vinyl record display stand (e.g.)
18. A "Settlers of Catan" set. I've got the travel edition which is great but it would be nicer to have a larger-sized set. There are some things I really like about the travel set that the full-size set lacks; so designing and printing a larger set myself could incorporate them. Also I don't feel inclined to buy the full-size set for 50 or so to end up with essentially the same game I already bought. No doubt I'd spent at least that much in PLA.
19. Little kids trinkets. Pacman ghosts, that sort-of thing. Whatever my daughters come up with next.
20. Lego storage/sorters.
21. Some kind of lenticular picture. Perhaps a gift or Christmas card combined in one.
22. A bracket to install a Gotek drive in my Amiga 500 (e.g.). I've managed without but the fit isn't great.
23. An attempt at using the 3D printer for 2D drawing. I would never get the same kind of quality results you can get from a proper plotter, but still Take a look at some proper plotter art!
24. Garden decorations. I like the idea of porous geometric shapes that you can plant mosses or ferns into, but also things which might be taken over and "used" by nature in ways I hadn't thought of.
25. Floor plans / 3D plans of my house (including variations if I remodelled)

from contextlib import contextmanager
@contextmanager
def bad():
    print(&aposin the context manager&apos)
    try:
        print("yielding value")
        yield &aposvalue&apos
    finally:
        return print(&aposcleaning up&apos)
@contextmanager
def good():
    print(&aposin the context manager&apos)
    try:
        print("yielding value")
        yield &aposvalue&apos
    finally:
        print(&aposcleaning up&apos)
with bad() as v:
    print(&aposgot v = %s&apos % v)
    raise Exception(&aposexception not raised!&apos)  # SILENCED!
print("this code is reached")
with good() as v:
    print(&aposgot v = %s&apos % v)
    raise Exception(&aposexpection normally raised&apos)
print("NOT REACHED (expected)")

1. define a bad context manager (the things you use with with statements) with contextlib.contextmanager) which:
   1. prints a debug statement
   2. return a value
   3. then returns and prints a debug statement
2. define a good context manager in much the same way, except it doesn't return, it just prints statement
3. use the bad context manager to show how it bypasses an exception
4. use the good context manager to show how it correctly raises the exception

in the context manager
yielding value
got v = value
cleaning up
this code is reached
in the context manager
yielding value
got v = value
cleaning up
Traceback (most recent call last):
  File "/home/anarcat/wikis/anarc.at/wtf.py", line 31, in <module>
    raise Exception('expection normally raised')
Exception: expection normally raised

If the suite was exited due to an exception, and the return value from the exit() method was false, the exception is reraised. If the return value was true, the exception is suppressed, and execution continues with the statement following the with statement.

import smtplib

from email.mime.multipart import MIMEMultipart
from email.mime.image import MIMEImage

msg = MIMEMultipart('alternative')
msg['Subject'] = "subject"
msg['From'] = from_addr
msg['To'] = to_addr

part = MIMEImage(open('/path/to/image', 'rb').read())

s = smtplib.SMTP('localhost')
s.sendmail(from_addr, to_addr, msg.as_string())
s.quit()

import smtplib

from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from email.mime.image import MIMEImage

msg = MIMEMultipart('alternative')
msg['Subject'] = "subject
msg['From'] = from_addr
msg['To'] = to_addr

text = MIMEText('<img src="cid:image1">', 'html')
msg.attach(text)

image = MIMEImage(open('/path/to/image', 'rb').read())

# Define the image's ID as referenced in the HTML body above
image.add_header('Content-ID', '<image1>')
msg.attach(image)

s = smtplib.SMTP('localhost')
s.sendmail(from_addr, to_addr, msg.as_string())
s.quit()

import smtplib

from email.mime.multipart import MIMEMultipart
from email.mime.image import MIMEImage

msg = MIMEMultipart('alternative')
msg['Subject'] = "subject"
msg['From'] = from_addr
msg['To'] = to_addr

part = MIMEImage(open('/path/to/image', 'rb').read())

s = smtplib.SMTP('localhost')
s.sendmail(from_addr, to_addr, msg.as_string())
s.quit()

import smtplib

from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from email.mime.image import MIMEImage

msg = MIMEMultipart('alternative')
msg['Subject'] = "subject
msg['From'] = from_addr
msg['To'] = to_addr

text = MIMEText('<img src="cid:image1">', 'html')
msg.attach(text)

image = MIMEImage(open('/path/to/image', 'rb').read())

# Define the image's ID as referenced in the HTML body above
image.add_header('Content-ID', '<image1>')
msg.attach(image)

s = smtplib.SMTP('localhost')
s.sendmail(from_addr, to_addr, msg.as_string())
s.quit()

Focus This month I didn't have any particular focus. I just worked on issues in my info bubble.

Changes

• freetype: restore donations
• OFTC website: cleanups, document account verification
• feed2exec: cleanups
• iotop-py: IRC channel
• whohas: fix URLs (1 2)
• Debian screenshots: deleted qutim (Windows)
• Debian wiki pages: BisectDebian, CrossCompiling, DebianHistory, Derivatives/Census/ToriOS, DeveloperNews, Hardware/Wanted, IRC, Manual-Howto, Mobile, PortsDocs/New, PrivacyIssues, screen, StaticLinking, Teams/DebianOnMobile
• FOSSjobs wiki pages: Resources

Issues

• Crashes in smart-notifier, gnome-shell-extension-shortcuts, bookworm, gdb
• AppArmor issues in avahi
• Conffile removal in gnome-session-common, dkms
• Features in Launchpad, ScanCode, plocate
• New versions of valgrind
• Warnings in smart-notifier
• Usability issues in GreaseMonkey
• Missing systemd integration for ddccontrol
• Syntax error in zephyr, python-editor
• Missing deps in libevolution, intel-gpu-tools
• Leakage in gnome-shell-extension-appindicator
• Broken links in libp11-kit-dev, nm.debian.org
• Out of sync description in libp11-kit-dev
• Incorrect links in cwrap.org
• Unknown errors in sm/freetype

Review

• Spam: reported 2 Debian bug reports and 73 Debian mailing list posts
• Patches: merged whohas/iotop-py/libusbgx patches
• Debian wiki: RecentChanges for the month
• Debian BTS usertags: changes for the month
• Debian screenshots:
  • approved 9menu awesome circuit-macros fvwm gpicview lm-sensors lxqt mousepad openbox qutim task-lxqt-desktop xfce4-settings
  • rejected webhttrack (screenshot of screenshots website), libc6 (random Android app), tesseract-ocr-all (random website), bpytop (hard to read, proprietary background image), p7zip-full (help output)

Administration

• Debian BTS: unarchive/reopen/triage bugs for reintroduced packages
• Debian IRC: disable anti-spam channel modes for some channels, rescue #debian-printing from retired chanop
• Debian wiki: unblock IP addresses, approve accounts

Communication

• Sent Debian Misc Developer News #56
• Respond to queries from Debian users and contributors on the mailing lists and IRC

Sponsors The valgrind bug was sponsored by my employer. All other work was done on a volunteer basis.

• [1] https://tinyurl.com/ygoyeuzr
• [2] https://tinyurl.com/yekmajo5
• [3] https://tinyurl.com/yzpkbeec
• [4] https://tinyurl.com/ygbq6ccf
• [5] https://shop.hak5.org/products/o-mg-cable-usb-a
• [6] https://tinyurl.com/yzfwg2a5
• [7] https://tinyurl.com/yz2a3vf3
• [8] https://tinyurl.com/yhd9zg72
• [9] https://tinyurl.com/yjg9wcj7
• [10] https://tinyurl.com/yf2exqva
• [11] https://locusmag.com/2021/09/cory-doctorow-breaking-in/
• [12] https://tinyurl.com/yzkh29mz
• [13] https://tinyurl.com/yhhg7xf2
• [14] https://tinyurl.com/yjktynmo