XDC 2024 in Montreal was another fantastic gathering for the Linux Graphics community. It was again a great time to immerse in the world of graphics development, engage in stimulating conversations, and learn from inspiring developers. Many Igalia colleagues and I participated in the conference again, delivering multiple talks about our work on the Linux Graphics stack and also organizing the Display/KMS meeting. This blog post is a detailed report on the Display/KMS meeting held during this XDC edition. Short on Time?

1. Catch the lightning talk summarizing the meeting here (you can even speed up 2x):

1. For a quick written summary, scroll down to the TL;DR section.

TL;DR This meeting took 3 hours and tackled a variety of topics related to DRM/KMS (Linux/DRM Kernel Modesetting):

• Sharing Drivers Between V4L2 and KMS: Brainstorming solutions for using a single driver for devices used in both camera capture and display pipelines.
• Real-Time Scheduling: Addressing issues with non-blocking page flips encountering sigkills under real-time scheduling.
• HDR/Color Management: Agreement on merging the current proposal, with NVIDIA implementing its special cases on VKMS and adding missing parts on top of Harry Wentland s (AMD) changes.
• Display Mux: Collaborative design discussions focusing on compositor control and cross-sync considerations.
• Better Commit Failure Feedback: Exploring ways to equip compositors with more detailed information for failure analysis.

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Bringing together Linux display developers in the XDC 2024 While I didn t present a talk this year, I co-organized a Display/KMS meeting (with Rodrigo Siqueira of AMD) to build upon the momentum from the 2024 Linux Display Next hackfest. The meeting was attended by around 30 people in person and 4 remote participants. Speakers: Melissa Wen (Igalia) and Rodrigo Siqueira (AMD) Link: https://indico.freedesktop.org/event/6/contributions/383/ Topics: Similar to the hackfest, the meeting agenda was built over the first two days of the conference and mixed talks follow-up with new ideas and ongoing community efforts. The final agenda covered five topics in the scheduled order:

1. How to share drivers between V4L2 and DRM for bridge-like components (new topic);
2. Real-time Scheduling (problems encountered after the Display Next hackfest);
3. HDR/Color Management (ofc);
4. Display Mux (from Display hackfest and XDC 2024 talk, bringing AMD and NVIDIA together);
5. (Better) Commit Failure Feedback (continuing the last minute topic of the Display Next hackfest).

Unpacking the Topics Similar to the hackfest, the meeting agenda evolved over the conference. During the 3 hours of meeting, I coordinated the room and discussion rounds, and Rodrigo Siqueira took notes and also contacted key developers to provide a detailed report of the many topics discussed. From his notes, let s dive into the key discussions!

How to share drivers between V4L2 and KMS for bridge-like components. Led by Laurent Pinchart, we delved into the challenge of creating a unified driver for hardware devices (like scalers) that are used in both camera capture pipelines and display pipelines.

• Problem Statement: How can we design a single kernel driver to handle devices that serve dual purposes in both V4L2 and DRM subsystems?
• Potential Solutions:
  1. Multiple Compatible Strings: We could assign different compatible strings to the device tree node based on its usage in either the camera or display pipeline. However, this approach might raise concerns from device tree maintainers as it could be seen as a layer violation.
  2. Separate Abstractions: A single driver could expose the device to both DRM and V4L2 through separate abstractions: drm-bridge for DRM and V4L2 subdev for video. While simple, this approach requires maintaining two different abstractions for the same underlying device.
  3. Unified Kernel Abstraction: We could create a new, unified kernel abstraction that combines the best aspects of drm-bridge and V4L2 subdev. This approach offers a more elegant solution but requires significant design effort and potential migration challenges for existing hardware.

Real-Time Scheduling Challenges We have discussed real-time scheduling during this year Linux Display Next hackfest and, during the XDC 2024, Jonas Adahl brought up issues uncovered while progressing on this front.

• Context: Non-blocking page-flips can, on rare occasions, take a long time and, for that reason, get a sigkill if the thread doing the atomic commit is a real-time schedule.
• Action items:
  • Explore alternative backtraces during the busy wait (e.g., ftrace).
  • Investigate the maximum thread time in busy wait to reproduce issues faced by compositors. Tools like RTKit (mutter) can be used for better control (Michel D nzer can help with this setup).

HDR/Color Management This is a well-known topic with ongoing effort on all layers of the Linux Display stack and has been discussed online and in-person in conferences and meetings over the last years. Here s a breakdown of the key points raised at this meeting:

• Talk: Color operations for Linux color pipeline on AMD devices: In the previous day, Alex Hung (AMD) presented the implementation of this API on AMD display driver.
• NVIDIA Integration: While they agree with the overall proposal, NVIDIA needs to add some missing parts. Importantly, they will implement these on top of Harry Wentland s (AMD) proposal. Their specific requirements will be implemented on VKMS (Virtual Kernel Mode Setting driver) for further discussion. This VKMS implementation can benefit compositor developers by providing insights into NVIDIA s specific needs.
• Other vendors: There is a version of the KMS API applied on Intel color pipeline. Apart from that, other vendors appear to be comfortable with the current proposal but lacks the bandwidth to implement it right now.
• Upstream Patches: The relevant upstream patches were can be found here. [As humorously notes, this series is eagerly awaiting your Acked-by (approval)]
• Compositor Side: The compositor developers have also made significant progress.
  • KDE has already implemented and validated the API through an experimental implementation in Kwin.
  • Gamescope currently uses a driver-specific implementation but has a draft that utilizes the generic version. However, some work is still required to fully transition away from the driver-specific approach. AP: work on porting gamescope to KMS generic API
  • Weston has also begun exploring implementation, and we might see something from them by the end of the year.
• Kernel and Testing: The kernel API proposal is well-refined and meets the DRM subsystem requirements. Thanks to Harry Wentland effort, we already have the API attached to two hardware vendors and IGT tests, and, thanks to Xaver Hugl, a compositor implementation in place.

Finally, there was a strong sense of agreement that the current proposal for HDR/Color Management is ready to be merged. In simpler terms, everything seems to be working well on the technical side - all signs point to merging and shipping the DRM/KMS plane color management API!

Display Mux During the meeting, Daniel Dadap led a brainstorming session on the design of the display mux switching sequence, in which the compositor would arm the switch via sysfs, then send a modeset to the outgoing driver, followed by a modeset to the incoming driver.

• Context:
  • During this year Linux Display Next hackfest, Mario Limonciello (AMD) introduced the topic and led a discussion on Display Mux.
  • Daniel Dadap (NVIDIA) retook this discussion with the XDC 2024 talk: Dynamic Switching of Display Muxes on Hybrid GPU Systems.
• Key Considerations:
  • HPD Handling: There was a general consensus that disabling HPD can be part of the sequence for internal panels and we don t need to focus on it here.
  • Cross-Sync: Ensuring synchronization between the compositor and the drivers is crucial. The compositor should act as the drm-master to coordinate the entire sequence, but how can this be ensured?
  • Future-Proofing: The design should not assume the presence of a mux. In future scenarios, direct sharing over DP might be possible.
• Action points:
  • Sharing DP AUX: Explore the idea of sharing DP AUX and its implications.
  • Backlight: The backlight definition represents a problem in the mux switch context, so we should explore some of the current specs available for that.

Towards Better Commit Failure Feedback In the last part of the meeting, Xaver Hugl asked for better commit failure feedback.

• Problem description: Compositors currently face challenges in collecting detailed information from the kernel about commit failures. This lack of granular data hinders their ability to understand and address the root causes of these failures.

To address this issue, we discussed several potential improvements:

• Direct Kernel Log Access: One idea is to directly load relevant kernel logs into the compositor. This would provide more detailed information about the failure and potentially aid in debugging.
• Finer-Grained Failure Reporting: We also explored the possibility of separating atomic failures into more specific categories. Not all failures are critical, and understanding the nature of the failure can help compositors take appropriate action.
• Enhanced Logging: Currently, the dmesg log doesn t provide enough information for user-space validation. Raising the log level to capture more detailed information during failures could be a viable solution.

By implementing these improvements, we aim to equip compositors with the necessary tools to better understand and resolve commit failures, leading to a more robust and stable display system.

A Big Thank You! Huge thanks to Rodrigo Siqueira for these detailed meeting notes. Also, Laurent Pinchart, Jonas Adahl, Daniel Dadap, Xaver Hugl, and Harry Wentland for bringing up interesting topics and leading discussions. Finally, thanks to all the participants who enriched the discussions with their experience, ideas, and inputs, especially Alex Goins, Antonino Maniscalco, Austin Shafer, Daniel Stone, Demi Obenour, Jessica Zhang, Joan Torres, Leo Li, Liviu Dudau, Mario Limonciello, Michel D nzer, Rob Clark, Simon Ser and Teddy Li. This collaborative effort will undoubtedly contribute to the continued development of the Linux display stack. Stay tuned for future updates!

Armadillo is a powerful and expressive C++ template library for linear algebra and scientific computing. It aims towards a good balance between speed and ease of use, has a syntax deliberately close to Matlab, and is useful for algorithm development directly in C++, or quick conversion of research code into production environments. RcppArmadillo integrates this library with the R environment and language and is widely used by (currently) 1191 other packages on CRAN, downloaded 37.2 million times (per the partial logs from the cloud mirrors of CRAN), and the CSDA paper (preprint / vignette) by Conrad and myself has been cited 603 times according to Google Scholar. Conrad released a minor version 14.2.0 a few days ago after we spent about two weeks with several runs of reverse-dependency checks covering corner cases. After a short delay at CRAN due to a false positive on a test, a package failing tests we also failed under the previous version, and some concern over new deprecation warnings _whem using the headers directly as _e.g. mlpack R package does we are now on CRAN. I noticed a missing feature under large 64bit word (for large floating-point matrices) and added an exporter for icube going to double to support the 64-bit integer range (as we already did, of course, for vectors and matrices). Changes since the last CRAN release are summarised below.

Changes in RcppArmadillo version 14.2.0-1 (2024-11-16)

• Upgraded to Armadillo release 14.2.0 (Smooth Caffeine)
  • Faster handling of symmetric matrices by inv() and rcond()
  • Faster handling of hermitian matrices by inv(), rcond(), cond(), pinv(), rank()
  • Added solve_opts::force_sym option to solve() to force the use of the symmetric solver
  • More efficient handling of compound expressions by solve()
• Added exporter specialisation for icube for the ARMA_64BIT_WORD case

Courtesy of my CRANberries, there is a diffstat report relative to previous release. More detailed information is on the RcppArmadillo page. Questions, comments etc should go to the rcpp-devel mailing list off the Rcpp R-Forge page. If you like this or other open-source work I do, you can sponsor me at GitHub.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

Review: Dark Deeds, by Michelle Diener

Series:	Class 5 #2
Publisher:	Eclipse
Copyright:	January 2016
ISBN:	0-6454658-4-4
Format:	Kindle
Pages:	340

Dark Deeds is the second book of the self-published Class 5 science fiction romance series. It is a sequel to Dark Horse and will spoil the plot of that book, but it follows the romance series convention of switching to a new protagonist in the same universe and telling a loosely-connected story. Fiona, like Rose in the previous book, was kidnapped by the Tecran in one of their Class 5 ships, although that's not entirely obvious at the start of the story. The book opens with her working as a slave on a Garmman trading ship while its captain works up the nerve to have her killed. She's spared this fate when the ship is raided by Krik pirates. Some brave fast-talking, and a touch of honor among thieves, lets her survive the raid and be rescued by a pursuing Grih battleship, with a useful electronic gadget as a bonus. The author uses the nickname "Fee" for Fiona throughout this book and it was like nails on a chalkboard every time. I had to complain about that before getting into the review. If you've read Dark Horse, you know the formula: lone kidnapped human woman, major violations of the laws against mistreatment of sentient beings that have the Grih furious on her behalf, hunky Grih starship captain who looks like a space elf, all the Grih are fascinated by her musical voice, she makes friends with a secret AI... Diener found a formula that worked well enough that she tried it again, and it would not surprise me if the formula repeated through the series. You should not go into this book expecting to be surprised. That said, the formula did work the first time, and it largely does work again. I thoroughly enjoyed Dark Horse and wanted more, and this is more, delivered on cue. There are worse things, particularly if you're a Kindle Unlimited reader (I am not) and are therefore getting new installments for free. The Tecran fascination with kidnapping human women is explained sufficiently in Fiona's case, but I am mildly curious how Diener will keep justifying it through the rest of the series. (Maybe the formula will change, but I doubt it.) To give Diener credit, this is not a straight repeat of the first book. Fiona is similar to Rose but not identical; Rose had an unshakable ethical calm, and Fiona is more of a scrapper. The Grih are not stupid and, given the amount of chaos Rose unleashed in the previous book, treat the sudden appearance of another human woman with a great deal more caution and suspicion. Unfortunately, this also means far less of my favorite plot element of the first book: the Grih being constantly scandalized and furious at behavior the protagonist finds sadly unsurprising. Instead, this book has quite a bit more action. Dark Horse was mostly character interactions and tense negotiations, with most of the action saved for the end. Dark Deeds replaces a lot of the character work with political plots and infiltrating secret military bases and enemy ships. The AI (named Eazi this time) doesn't show up until well into the book and isn't as much of a presence as Sazo. Instead, there's a lot more of Fiona being drafted into other people's fights, which is entertaining enough while it's happening but which wasn't as delightful or memorable as Rose's story. The writing continues to be serviceable but not great. It's a bit cliched and a bit awkward. Also, Diener uses paragraph breaks for emphasis. It's hard to stop noticing it once you see it. Thankfully, once the story gets going and there's more dialogue, she tones that down, or perhaps I stopped noticing. It's that kind of book (and that kind of series): it's a bit rough to get started, but then there's always something happening, the characters involve a whole lot of wish-fulfillment but are still people I like reading about, and it's the sort of unapologetic "good guys win" type of light science fiction that is just the thing when one simply wants to be entertained. Once I get into the book, it's easy to overlook its shortcomings. I spent Dark Horse knowing roughly what would happen but wondering about the details. I spent Dark Deeds fairly sure of the details and wondering when they would happen. This wasn't as fun of an experience, but the details were still enjoyable and I don't regret reading it. I am hoping that the next book will be more of a twist, or will have a character more like Rose (or at least a character with a better nickname). Sort of recommended if you liked Dark Horse and really want more of the same. Followed by Dark Minds, which I have already purchased. Rating: 6 out of 10

In basically every engineering organization I ve ever regarded as particularly high functioning, I ve sat through one specific recurring conversation which is not a conversation about complexity . Things are good or bad because they are or aren t complex, architectures needs to be redone because it s too complex some refactor of whatever it is won t work because it s too complex. You may have even been a part of some of these conversations or even been the one advocating for simple light-weight solutions. I ve done it. Many times. Rarely, if ever, do we talk about complexity within its rightful context complexity for whom. Is a solution complex because it s complex for the end user? Is it complex if it s complex for an API consumer? Is it complex if it s complex for the person maintaining the API service? Is it complex if it s complex for someone outside the team maintaining it to understand? Complexity within a problem domain I ve come to believe, is fairly zero-sum there s a fixed amount of complexity in the problem to be solved, and you can choose to either solve it, or leave it for those downstream of you to solve that problem on their own. That being said, while I believe there is a lower bound in complexity to contend with for a problem, I do not believe there is an upper bound to the complexity of solutions possible. It is always possible, and in fact, very likely that teams create problems for themselves while trying to solve a problem. The rest of this post is talking to the lower bound. When getting feedback on an early draft of this blog post, I ve been informed that Fred Brooks coined a term for what I call lower bound complexity Essential Complexity , in the paper No Silver Bullet Essence and Accident in Software Engineering , which is a better term and can be used interchangeably.

Complexity Culture In a large enough organization, where the team is high functioning enough to have and maintain trust amongst peers, members of the team will specialize. People will begin to engage with subsets of the work to be done, and begin to have their efficacy measured against that part of the organization s problems. Incentives shift, and over time it becomes increasingly likely that two engineers may have two very different priorities when working on the same system together. Someone accountable for uptime and tasked with responding to outages will begin to resist changes. Someone accountable for rapidly delivering features will resist gates between them and their users. Companies (either wittingly or unwittingly) will deal with this by tasking engineers with both production (feature development) and operational tasks (maintenance), so the difference in incentives isn t usually as bad as it could be. When we get a bunch of folks from far-flung corners of an organization in a room, fire up a slide deck and throw up some aspirational to-be architecture diagram in order to get a sign-off to solve some problem (be it someone needs a credible promotion packet, new feature needs to get delivered, or the system has begun to fail and needs fixing), the initial reaction will, more often than I d like, start to devolve into a discussion of how this is going to introduce a bunch of complexity, going to be hard to maintain, why can t you make it less complex? Right around here is when I start to try and contextualize the conversation happening around me understand what complexity is that being discussed, and understand who is taking on that burden. Think about who should be owning that problem, and work through the tradeoffs involved. Is it best solved here, or left to consumers (be them other systems, developers, or users). Should something become an API call s optional param, taking on all the edge-cases and on, or should users have to implement the logic using the data you return (leaving everyone else to take on all the edge-cases and maintenance)? Should you process the data, or require the user to preprocess it for you? Frequently it s right to make an active and explicit decision to simplify and leave problems to be solved downstream, since they may not actually need to be solved or perhaps you expect consumers will want to own the specifics of how the problem is solved, in which case you leave lots of documentation and examples. Many other times, especially when it s something downstream consumers are likely to hit, it s best solved internal to the system, since the only thing that can come of leaving it unsolved are bugs, frustration and half-correct solutions. This is a grey-space of tradeoffs, not a clear decision tree. No one wants the software manifestation of a katamari ball or a junk drawer, nor does anyone want a half-baked service unable to handle the simplest use-case.

Head-in-sand as a Service Popoffs about how complex something is, are, to a first approximation, best understood as meaning complicated for the person making comments . A lot of the #thoughtleadership believe that an AWS hosted EKS k8s cluster running images built by CI talking to an AWS hosted PostgreSQL RDS is not complex. They re right. Mostly right. This is less complex less complex for them. It s not, however, without complexity and its own tradeoffs it s just complexity that they do not have to deal with. Now they don t have to maintain machines that have pesky operating systems or hard drive failures. They don t have to deal with updating the version of k8s, nor ensuring the backups work. No one has to push some artifact to prod manually. Deployments happen unattended. You click a button and get a cluster. On the other hand, developers outside the ops function need to deal with troubleshooting CI, debugging access control rules encoded in turing complete YAML, permissions issues inside the cluster due to whatever the fuck a service mesh is, everyone needs to learn how to use some k8s tools they only actually use during a bad day, likely while doing some x.509 troubleshooting to connect to the cluster (an internal only endpoint; just port forward it) not to mention all sorts of rules to route packets to their project (a single repo s binary being run in 3 containers on a single vm host). Beyond that, there s the invisible complexity complexity on the interior of a service you depend on. I think about the dozens of teams maintaining the EKS service (which is either run on EC2 instances, or alternately, EC2 instances in a trench coat, moustache and even more shell scripts), the RDS service (also EC2 and shell scripts, but this time accounting for redundancy, backups, availability zones), scores of hypervisors pulled off the shelf (xen, kvm) smashed together with the ones built in-house (firecracker, nitro, etc) running on hardware that has to be refreshed and maintained continuously. Every request processed by network ACL rules, AWS IAM rules, security group rules, using IP space announced to the internet wired through IXPs directly into ISPs. I don t even want to begin to think about the complexity inherent in how those switches are designed. Shitloads of complexity to solve problems you may or may not have, or even know you had. What s more complex? An app running in an in-house 4u server racked in the office s telco closet in the back running off the office Verizon line, or an app running four hypervisors deep in an AWS datacenter? Which is more complex to you? What about to your organization? In total? Which is more prone to failure? Which is more secure? Is the complexity good or bad? What type of Complexity can you manage effectively? Which threaten the system? Which threaten your users?

COMPLEXIVIBES This extends beyond Engineering. Decisions regarding what tools are we able to use be them existing contracts with cloud providers, CIO mandated SaaS products, a list of the only permissible open source projects will incur costs in terms of expressed complexity . Pinning open source projects to a fixed set makes SBOM production less complex . Using only one SaaS provider s product suite (even if its terrible, because it has all the types of tools you need) makes accreditation less complex . If all you have is a contract with Pauly T s lowest price technically acceptable artisinal cloudary and haberdashery, the way you pay for your compute is less complex for the CIO shop, though you will find yourself building your own hosted database template, mechanism to spin up a k8s cluster, and all the operational and technical burden that comes with it. Or you won t and make it everyone else s problem in the organization. Nothing you can do will solve for the fact that you must now deal with this problem somewhere because it was less complicated for the business to put the workloads on the existing contract with a cut-rate vendor. Suddenly, the decision to reduce complexity because of an existing contract vehicle has resulted in a huge amount of technical risk and maintenance burden being onboarded. Complexity you would otherwise externalize has now been taken on internally. With a large enough organizations (specifically, in this case, i m talking about you, bureaucracies), this is largely ignored or accepted as normal since the personnel cost is understood to be free to everyone involved. Doing it this way is more expensive, more work, less reliable and less maintainable, and yet, somehow, is, in a lot of ways, less complex to the organization. It s particularly bad with bureaucracies, since screwing up a contract will get you into much more trouble than delivering a broken product, leaving basically no reason for anyone to care to fix this. I can t shake the feeling that for every story of technical mandates gone awry, somewhere just out of sight there s a decisionmaker optimizing for what they believe to be the least amount of complexity least hassle, fewest unique cases, most consistency as they can. They freely offload complexity from their accreditation and risk acceptance functions through mandates. They will never have to deal with it. That does not change the fact that someone does.

TC;DR (TOO COMPLEX; DIDN T REVIEW) We wish to rid ourselves of systemic Complexity after all, complexity is bad, simplicity is good. Removing upper-bound own-goal complexity ( accidental complexity in Brooks s terms) is important, but once you hit the lower bound complexity, the tradeoffs become zero-sum. Removing complexity from one part of the system means that somewhere else maybe outside your organization or in a non-engineering function must grow it back. Sometimes, the opposite is the case, such as when a previously manual business processes is automated. Maybe that s a good idea. Maybe it s not. All I know is that what doesn t help the situation is conflating complexity with everything we don t like legacy code, maintenance burden or toil, cost, delivery velocity.

• Complexity is not the same as proclivity to failure. The most reliable systems I ve interacted with are unimaginably complex, with layers of internal protection to prevent complete failure. This has its own set of costs which other people have written about extensively.
• Complexity is not cost. Sometimes the cost of taking all the complexity in-house is less, for whatever value of cost you choose to use.
• Complexity is not absolute. Something simple from one perspective may be wildly complex from another. The impulse to burn down complex sections of code is helpful to have generally, but sometimes things are complicated for a reason, even if that reason exists outside your codebase or organization.
• Complexity is not something you can remove without introducing complexity elsewhere. Just as not making a decision is a decision itself; choosing to require someone else to deal with a problem rather than dealing with it internally is a choice that needs to be considered in its full context.

Next time you re sitting through a discussion and someone starts to talk about all the complexity about to be introduced, I want to pop up in the back of your head, politely asking what does complex mean in this context? Is it lower bound complexity? Is this complexity desirable? Is what they re saying mean something along the lines of I don t understand the problems being solved, or does it mean something along the lines of this problem should be solved elsewhere? Do they believe this will result in more work for them in a way that you don t see? Should this not solved at all by changing the bounds of what we should accept or redefine the understood limits of this system? Is the perceived complexity a result of a decision elsewhere? Who s taking this complexity on, or more to the point, is failing to address complexity required by the problem leaving it to others? Does it impact others? How specifically? What are you not seeing? What can change? What should change?

Version 0.0.19 of RcppSpdlog arrived on CRAN early this morning and has been uploaded to Debian. RcppSpdlog bundles spdlog, a wonderful header-only C++ logging library with all the bells and whistles you would want that was written by Gabi Melman, and also includes fmt by Victor Zverovich. You can learn more at the nice package documention site. This releases updates the code to the version 1.15.0 of spdlog which was released on Saturday, and contains fmt 11.0.2. It also contains a contributed PR which allows use std::format under C++20, bypassing fmt (with some post-merge polish too), and another PR correcting a documentation double-entry. The NEWS entry for this release follows.

Changes in RcppSpdlog version 0.0.19 (2024-11-10)

• Support use of std::format under C++20 via opt-in define instead of fmt (Xanthos Xanthopoulos in #19)
• An erroneous duplicate log=level documentation level was removed (Contantinos Giachalis in #20)
• Upgraded to upstream release spdlog 1.15.0 (Dirk in #21)
• Partially revert / simplify src/formatter.cpp accomodating both #19 and previous state (Dirk in #21)

Courtesy of my CRANberries, there is also a diffstat report. More detailed information is on the RcppSpdlog page, or the package documention site. If you like this or other open-source work I do, you can sponsor me at GitHub.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

A new release of the inline package got to CRAN today marking the first release in three and half years. inline facilitates writing code in-line in simple string expressions or short files. The package was used quite extensively by Rcpp in the very early days before Rcpp Attributes arrived on the scene providing an even better alternative for its use cases. inline is still used by rstan and a number of other packages. This release was tickled by changing in r-devel just this week, and the corresponding please fix or else email I received this morning. R_NO_REMAP is now the default in r-devel, and while we had already converted most (old-style) calls into the API to using the now mandatory Rf_ prefix, the package contained few remaining cases in examples as well as one in code generation. The release also contains a helpful contributed PR making an error message a little clearer, plus several small and common maintenance changed around continuous integration, package layout and the repository. The NEWS extract follows and details the changes some more.

Changes in inline version 0.3.20 (2024-11-10)

• Error message formatting is improved for compileCode (Alexis Derumigny in #25)
• Switch to using Authors@R, other general packaging maintenance for continuous integration and repository
• Use Rf_ in a handful of cases as R-devel now mandates it

Thanks to my CRANberries, you can also look at a diff to the previous release Questions, comments etc should go to the rcpp-devel mailing list off the R-Forge page. Bugs reports are welcome at the GitHub issue tracker as well (where one can also search among open or closed issues). If you like this or other open-source work I do, you can sponsor me at GitHub.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

Welcome to the October 2024 report from the Reproducible Builds project. Our reports attempt to outline what we ve been up to over the past month, highlighting news items from elsewhere in tech where they are related. As ever, if you are interested in contributing to the project, please visit our Contribute page on our website. Table of contents:

1. Beyond bitwise equality for Reproducible Builds?
2. Two Ways to Trustworthy at SeaGL 2024
3. Number of cores affected Android compiler output
4. On our mailing list
5. diffoscope
6. IzzyOnDroid passed 25% reproducible apps
7. Distribution work
8. Website updates
9. Reproducibility testing framework
10. Supply-chain security at Open Source Summit EU
11. Upstream patches

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Beyond bitwise equality for Reproducible Builds? Jens Dietrich, Tim White, of Victoria University of Wellington, New Zealand along with Behnaz Hassanshahi and Paddy Krishnan of Oracle Labs Australia published a paper entitled Levels of Binary Equivalence for the Comparison of Binaries from Alternative Builds :

The availability of multiple binaries built from the same sources creates new challenges and opportunities, and raises questions such as: Does build A confirm the integrity of build B? or Can build A reveal a compromised build B? . To answer such questions requires a notion of equivalence between binaries. We demonstrate that the obvious approach based on bitwise equality has significant shortcomings in practice, and that there is value in opting for alternative notions. We conceptualise this by introducing levels of equivalence, inspired by clone detection types.

A PDF of the paper is freely available.

Two Ways to Trustworthy at SeaGL 2024 On Friday 8th November, Vagrant Cascadian will present a talk entitled Two Ways to Trustworthy at SeaGL in Seattle, WA. Founded in 2013, SeaGL is a free, grassroots technical summit dedicated to spreading awareness and knowledge about free source software, hardware and culture. Vagrant s talk:

[ ] delves into how two project[s] approaches fundamental security features through Reproducible Builds, Bootstrappable Builds, code auditability, etc. to improve trustworthiness, allowing independent verification; trustworthy projects require little to no trust. Exploring the challenges that each project faces due to very different technical architectures, but also contextually relevant social structure, adoption patterns, and organizational history should provide a good backdrop to understand how different approaches to security might evolve, with real-world merits and downsides.

Number of cores affected Android compiler output Fay Stegerman wrote that the cause of the Android toolchain bug from September s report that she reported to the Android issue tracker has been found and the bug has been fixed.

the D8 Java to DEX compiler (part of the Android toolchain) eliminated a redundant field load if running the class s static initialiser was known to be free of side effects, which ended up accidentally depending on the sharding of the input, which is dependent on the number of CPU cores used during the build.

To make it easier to understand the bug and the patch, Fay also made a small example to illustrate when and why the optimisation involved is valid.

On our mailing list On our mailing list this month:

• Following-up to previous work, James Addison informed the list that the recently-released Sphinx documentation generator includes improvements to the next copyright notice substitutions.
• Pol Dellaiera wrote to the list in order to seek advice around introducing the concept of reproducibility to computer science Masters students at the University of Mons, Belgium.
• James Addison also followed-up to a previous thread on CONFIG_MODULE_SIG and the unreproducible Linux Kernel to add: I wonder whether it would be possible to use the Linux kernel s Integrity Policy Enforcement to deploy a policy that would prevent loading of anything except a set of expected kernel modules. [ ]
• There were also two informative replies from David Wheeler to a broad-based discussion on Reproducible Builds being defined in various standards. [ ][ ]

diffoscope diffoscope is our in-depth and content-aware diff utility that can locate and diagnose reproducibility issues. This month, Chris Lamb made the following changes, including preparing and uploading versions 279, 280, 281 and 282 to Debian:

• Ignore errors when listing .ar archives (#1085257). [ ]
• Don t try and test with systemd-ukify in the Debian stable distribution. [ ]
• Drop Depends on the deprecated python3-pkg-resources (#1083362). [ ]

In addition, Jelle van der Waa added support for Unified Kernel Image (UKI) files. [ ][ ][ ] Furthermore, Vagrant Cascadian updated diffoscope in GNU Guix to version 282. [ ][ ]

IzzyOnDroid passed 25% reproducible apps The IzzyOnDroid project has reached a good milestone by reaching over 25% of the ~1,200 Android apps provided by their repository (of official APKs built by the original application developers) having been confirmed to be reproducible by a rebuilder.

Distribution work In Debian this month:

• Holger Levsen uploaded devscripts version 2.24.2, including many changes to the debootsnap, debrebuild and reproducible-check scripts. This is the first time that debrebuild actually works (using sbuild s unshare backend). As part of this, Holger also fixed an issue in the reproducible-check script where a typo in the code led to incorrect results [ ]
• Recently, a news entry was added to snapshot.debian.org s homepage, describing the recent changes that made the system stable again:

  The new server has no problems keeping up with importing the full archives on every update, as each run finishes comfortably in time before it s time to run again. [While] the new server is the one doing all the importing of updated archives, the HTTP interface is being served by both the new server and one of the VM s at LeaseWeb.

  The entry list a number of specific updates surrounding the API endpoints and rate limiting.
• Lastly, 12 reviews of Debian packages were added, 3 were updated and 18 were removed this month adding to our knowledge about identified issues.

Elsewhere in distribution news, Zbigniew J drzejewski-Szmek performed another rebuild of Fedora 42 packages, with the headline result being that 91% of the packages are reproducible. Zbigniew also reported a reproducibility problem with QImage. Finally, in openSUSE, Bernhard M. Wiedemann published another report for that distribution.

Website updates There were an enormous number of improvements made to our website this month, including:

• Alba Herrerias:
  • Improve consistency across distribution-specific guides. [ ]
  • Fix a number of links on the Contribute page. [ ]
• Chris Lamb:
  • Correct the name of Civil Infrastructure Platform name and update image on the Projects page. [ ]
  • Update broken link on the Value Initialization page. [ ]
  • Try and make pipeline/branch builds of the website easier to browse. [ ][ ][ ][ ]
• hulkoba
  • Contribute to the new Success stories page. [ ]
• James Addison:
  • Huge and significant work on a (as-yet-merged) quickstart guide to be linked from the homepage [ ][ ][ ][ ][ ]
  • On the homepage, link directly to the Projects subpage. [ ]
  • Relocate dependency-drift notes to the Volatile inputs page. [ ]
• Ninette Adhikari:
  • Add a brand new Success stories page that highlights the success stories of Reproducible Builds, showcasing real-world examples of projects shipping with verifiable, reproducible builds . [ ][ ][ ][ ][ ][ ]
• Pol Dellaiera:
  • Update the website s README page for building the website under NixOS. [ ][ ][ ][ ][ ]
  • Add a new academic paper citation. [ ]

Lastly, Holger Levsen filed an extensive issue detailing a request to create an overview of recommendations and standards in relation to reproducible builds.

Reproducibility testing framework The Reproducible Builds project operates a comprehensive testing framework running primarily at tests.reproducible-builds.org in order to check packages and other artifacts for reproducibility. In October, a number of changes were made by Holger Levsen, including:

• Add a basic index.html for rebuilderd. [ ]
• Update the nginx.conf configuration file for rebuilderd. [ ]
• Document how to use a rescue system for Infomaniak s OpenStack cloud. [ ]
• Update usage info for two particular nodes. [ ]
• Fix up a version skew check to fix the name of the riscv64 architecture. [ ]
• Update the rebuilderd-related TODO. [ ]

In addition, Mattia Rizzolo added a new IP address for the inos5 node [ ] and Vagrant Cascadian brought 4 virt nodes back online [ ].

Supply-chain security at Open Source Summit EU The Open Source Summit EU took place recently, and covered plenty of topics related to supply-chain security, including:

• Public Sector & OpenSSF: Principles for Package Repository Security
• The Model Openness Framework: Promoting Completeness and Openness for Reproducibility, Transparency and Usability in AI
• Structured Scorecard Results: Tailor Your Own Supply-Chain Security Policies
• Lightning Talk: Elephant in the Room: How Supply Chain Security Standards Are Not Standard and What to Do About It
• Lightning Talk: Charting the Course for Secure Software Supply Chain with Guac-AI-Mole!
• TPMs, Merkle Trees and TEEs: Enhancing SLSA with Hardware-Assisted Build Environment Verification
• Accountability Taxonomy for AI Software Bill of Materials
• Securing Your Supply Chain with an Open Source Ecosystem
• OSS Supply Chain Threats and Why You Need a Holistic Security Strategy
• A Step Closer to in-Toto lly Secure: Using in-Toto and OPA Gatekeeper to Verify Artifact Integrity
• Panel Discussion: Improving Supply Chain Integrity with OpenSSF Technologies
• Case Study: 10+ Years of Developing an SBOM System and the Dos and Don ts
• SBOM in SaaS Environments: An Update
• Securing Git Repositories with Gittuf

Upstream patches The Reproducible Builds project detects, dissects and attempts to fix as many currently-unreproducible packages as possible. We endeavour to send all of our patches upstream where appropriate. This month, we wrote a large number of such patches, including:

• Bernhard M. Wiedemann
  • apache-ivy (.zip modification time)
  • ccache (build failure)
  • colord (CPU)
  • efivar (CPU/march=native)
  • gsl (no check)
  • libcamera (date/copyright year)
  • libreoffice (possible rpm/build toolchain corruption bug)
  • moto (.gz modification time)
  • openssl-1_1 (date-related issue)
  • python-pygraphviz (benchmark)
  • sphinx/python-pygraphviz (benchmark)
  • python-panel (package.lock has random port)
  • python-propcache (random temporary path)
  • python314 (.gz-related modification time)
  • rusty_v8 (random .o files)
  • scapy (date)
  • wine (parallelism)
  • ibmtss (FTBFS-2026)
  • pymol (date)
  • pandas (ASLR)
  • linutil (drop date)
  • lsof (also filed in openSUSE: uname -r in LSOF_VSTR)
  • schily (also filed in openSUSE: uname -r)
  • superlu (nocheck)
  • util (random test failure)
  • ceph (year-2038 variation from embedded boost)
• Chris Lamb:
  • #1085097 filed against python-roborock.
  • #1085280 filed against pywayland.
  • #1085283 filed against readsb.
  • #1085381 filed against xraylarch.
• James Addison:
  • #1085112 filed against distro-info.
• Zbigniew J drzejewski-Szmek:
  • calibre (two sort issues) [ ][ ]

---

Finally, 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.
• Mastodon: @reproducible_builds@fosstodon.org
• Mailing list: rb-general@lists.reproducible-builds.org
• Twitter: @ReproBuilds

FTP master This month I accepted 398 and rejected 22 packages. The overall number of packages that got accepted was 441. In case your RM bug is not closed within a month, you can assume that either the conversion of the subject of the bug email to the corresponding dak command did not work or you still need to take care of reverse dependencies. The dak command related to your removal bug can be found here. Unfortunately the bahavior of some project members caused a decline of motivation of team members to work on these bugs. When I look at these bugs, I just copy and paste the above mentioned dak commands. If they don t work, I don t have the time to debug what is going wrong. So please read the docs and take care of it yourself. Please also keep in mind that you need to close the bug or set a moreinfo tag if you don t want anybody to act on your removal bug. Debian LTS This was my hundred-twenty-fourth month that I did some work for the Debian LTS initiative, started by Raphael Hertzog at Freexian. During my allocated time I uploaded or worked on:

• [DLA 3925-1] asterisk security update to fix two CVEs related to privilege escalation and DoS
• [DLA 3940-1] xorg-server update to fix one CVE related to privilege escalation

Last but not least I did a week of FD this month and attended the monthly LTS/ELTS meeting. Debian ELTS This month was the seventy-fifth ELTS month. During my allocated time I uploaded or worked on:

• [ELA-1198-1]cups security update for one CVE in Buster to fix the IPP attribute related CVEs.
• [ELA-1199-1]cups security update for two CVEs in Stretch to fix the IPP attribute related CVEs
• [ELA-1216-1]graphicsmagick security update for one CVE in Jessie
• [ELA-1217-1]asterisk security update for two CVEs in Buster related to privilege escalation
• [ELA-1218-1]asterisk security update for two CVEs in Stretch related to privilege escalation and DoS
• [ELA-1223-1]xorg-server security update for one CVE in Jessie, Stretch and Buster related to privilege escalation

I also did a week of FD and attended the monthly LTS/ELTS meeting. Debian Printing Unfortunately I didn t found any time to work on this topic. Debian Matomo Unfortunately I didn t found any time to work on this topic. Debian Astro Unfortunately I didn t found any time to work on this topic. Debian IoT This month I uploaded new upstream or bugfix versions of:

• pywws (yes, again this month)

Debian Mobcom This month I uploaded new packages or new upstream or bugfix versions of:

• osmocom-dahdi-linux (package prepared by Nathan)
• osmo-bts

misc This month I uploaded new upstream or bugfix versions of:

• mlat-client-adsbfi
• mailio
• readsb
• pipexec

The topic of this posting already tells you that an old Unix guy tells stories about old techniques. I'm a happy NIS (formerly YP) user since 30+ years. I started using it with SunOS 4.0, later using it with Solaris and with Linux since 1999. In the past, a colleague wasn't happyly using NIS+ when he couldn't log in as root after a short time because of some well known bugs and wrong configs. NIS+ was also much slower than my NIS setup. I know organisations using NIS for more than 80.000 user accounts in 2024. I know the security implications of NIS but I can live with them, because I manage all computers in the network that have access to the NIS maps. And NIS on Linux offers to use shadow maps, which are only accessible to the root account. My users are forced to use very long passwords. Unfortunately NIS support for the PAM modules was removed in Debian in pam 1.4.0-13, which means Debian 12 (bookworm) is lacking NIS support in PAM, but otherwise it is still supported. This only affects changing the NIS password via passwd. You can still authenticate users and use other NIS maps. But yppasswd is deprecated and you should not use it! If you use yppasswd it may generate a new password hash by using the old DES crypt algorithm, which is very weak and only uses the first 8 chars in your password. Do not use yppasswd any more! yppasswd only detects DES, MD5, SHA256 and SHA512 hashes, but for me and some colleagues it only creates weak DES hashes after a password change. yescrypt hashes which are the default in Debian 12 are not supported at all. The solution is to use the plain passwd program. On the NIS master, you should setup your NIS configuration to use /etc/shadow and /etc/passwd even if your other NIS maps are in /var/yp/src or similar. Make sure to have these lines in your /var/yp/Makefile:

PASSWD      = /etc/passwd
SHADOW      = /etc/shadow

Call make once, and it will generate the shadow and passwd map. You may want to set the variable MINUID which defines which entries are not put into the NIS maps. On all NIS clients you still need the entries (for passwd, shadow, group,...) that point to the nis service. E.g.:

passwd:         files nis systemd
group:          files nis systemd
shadow:         files nis

You can remove all occurences of "nis" in your /etc/pam.d/common-password file. Then you can use the plain passwd program to change your password on the NIS master. But this does not call make in /var/yp for updating the NIS shadow map. Let's use inotify(7) for that. First, create a small shell script /usr/local/sbin/shadow-change:

#! /bin/sh
PATH=/usr/sbin:/usr/bin
# only watch the /etc/shadow file
if [ "$2" != "shadow" ]; then
  exit 0
fi
cd /var/yp   exit 3
sleep 2
make

Then install the package incron.

# apt install incron
# echo root >> /etc/incron.allow
# incrontab -e

Add this line:

/etc    IN_MOVED_TO     /usr/local/sbin/shadow-change $@ $# $%

It's not possible to use IN_MODIFY or watch other events on /etc/shadow directly, because the passwd command creates a /etc/nshadow file, deletes /etc/shadow and then moves nshadow to shadow. inotify on a file does not work after the file was removed. You can see the logs from incrond by using:

# journalctl _COMM=incrond
e.g.
Oct 01 12:21:56 kueppers incrond[6588]: starting service (version 0.5.12, built on Jan 27 2023 23:08:49)
Oct 01 13:43:55 kueppers incrond[6589]: table for user root created, loading
Oct 01 13:45:42 kueppers incrond[6589]: PATH (/etc) FILE (shadow) EVENT (IN_MOVED_TO)
Oct 01 13:45:42 kueppers incrond[6589]: (root) CMD ( /usr/local/sbin/shadow-change /etc shadow IN_MOVED_TO)

I've disabled the execution of yppasswd using dpkg-divert

# dpkg-divert --local --rename --divert /usr/bin/yppasswd-disable /usr/bin/yppasswd
chmod a-rwx /usr/bin/yppasswd-disable

Do not forget to limit the access to the shadow.byname map in ypserv.conf and general access to NIS in ypserv.securenets. I've also discovered the package pamtester, which is a nice package for testing your pam configs.

Debian Contributions: 2024-10 Contributing to Debian is part of Freexian s mission. This article covers the latest achievements of Freexian and their collaborators. All of this is made possible by organizations subscribing to our Long Term Support contracts and consulting services.

rebootstrap, by Helmut Grohne After significant changes earlier this year, the state of architecture cross bootstrap is normalizing again. More and more architectures manage to complete rebootstrap testing successfully again. Here are two examples of what kind of issues the bootstrap testing identifies. At some point, libpng1.6 would fail to cross build on musl architectures whereas it would succeed on other ones failing to locate zlib. Adding --debug-find to the cmake invocation eventually revealed that it would fail to search in /usr/lib/<triplet>, which is the default library path. This turned out to be a bug in cmake assuming that all linux systems use glibc. libpng1.6 also gained a baseline violation for powerpc and ppc64 by enabling the use of AltiVec there. The newt package would fail to cross build for many 32-bit architectures whereas it would succeed for armel and armhf due to -Wincompatible-pointer-types. It turns out that this flag was turned into -Werror and it was compiling with a warning earlier. The actual problem is a difference in signedness between wchar_t and FriBidChar (aka uint32_t) and actually affects native building on i386.

Miscellaneous contributions

• Helmut sent 35 patches for cross build failures.
• Stefano Rivera uploaded the Python 3.13.0 final release.
• Stefano continued to rebuild Python packages with C extensions using Python 3.13, to catch compatibility issues before the 3.13-add transition starts.
• Stefano uploaded new versions of a handful of Python packages, including: dh-python, objgraph, python-mitogen, python-truststore, and python-virtualenv.
• Stefano packaged a new release of mkdocs-macros-plugin, which required packaging a new Python package for Debian, python-super-collections (now in NEW review).
• Stefano helped the mini-DebConf Online Brazil get video infrastructure up and running for the event. Unfortunately, Debian s online-DebConf setup has bitrotted over the last couple of years, and it eventually required new temporary Jitsi and Jibri instances.
• Colin Watson fixed a number of autopkgtest failures to get ansible back into testing.
• Colin fixed an ssh client failure in certain cases when using GSS-API key exchange, and added an integration test to ensure this doesn t regress in future.
• Colin worked on the Python 3.13 transition, fixing problems related to it in 15 packages. This included upstream work in a number of packages (postgresfixture, python-asyncssh, python-wadllib).
• Colin upgraded 41 Python packages to new upstream versions.
• Carles improved po-debconf-manager: now it can create merge requests to Salsa automatically (created 17, new batch coming this month), imported almost all the packages with debconf translation templates whose VCS is Salsa (currently 449 imported), added statistics per package and language, improved command line interface options. Performed user support fixing different issues. Also prepared an abstract for the talk at MiniDebConf Toulouse.
• Santiago Ruano Rinc n continued the organization work for the DebConf 25 conference, to be held in Brest, France. Part of the work relates to the initial edits of the sponsoring brochure. Thanks to Benjamin Somers who finalized the French and English versions.
• Rapha l forwarded a couple of zim and hamster bugs to the upstream developers, and tried to diagnose a delayed startup of gdm on his laptop (cf #1085633).
• On behalf of the Debian Publicity Team, Anupa interviewed 7 women from the Debian community, old and new contributors. The interview was published in Bits from Debian.

In September of this year, I visited Kenya to attend the State of the Map conference. I spent six nights in the capital Nairobi, two nights in Mombasa, and one night on a train. I was very happy with the visa process being smooth and quick. Furthermore, I stayed at the Nairobi Transit Hotel with other attendees, with Ibtehal from Bangladesh as my roommate. One of the memorable moments was the time I spent at a local coffee shop nearby. We used to go there at midnight, despite the grating in the shops suggesting such adventures were unsafe. Fortunately, nothing bad happened, and we were rewarded with a fun time with the locals.

The coffee shop Ibtehal and me used to visit during the midnight

Grating at a chemist shop in Mombasa, Kenya

The country lies on the equator, which might give the impression of extremely hot temperatures. However, Nairobi was on the cooler side (10 25 degrees Celsius), and I found myself needing a hoodie, which I bought the next day. It also served as a nice souvenir, as it had an outline of the African map printed on it. I also bought a Safaricom SIM card for 100 shillings and recharged it with 1000 shillings for 8 GB internet with 5G speeds and 400 minutes talk time.

A visit to Nairobi s Historic Cricket Ground On this trip, I got a unique souvenir that can t be purchased from the market a cricket jersey worn in an ODI match by a player. The story goes as follows: I was roaming around the market with my friend Benson from Nairobi to buy a Kenyan cricket jersey for myself, but we couldn t find any. So, Benson had the idea of visiting the Nairobi Gymkhana Club, which used to be Kenya s main cricket ground. It has hosted some historic matches, including the 2003 World Cup match in which Kenya beat the mighty Sri Lankans and the record for the fastest ODI century by Shahid Afridi in just 37 balls in 1996. Although entry to the club was exclusively for members, I was warmly welcomed by the staff. Upon reaching the cricket ground, I met some Indian players who played in Kenyan leagues, as well as Lucas Oluoch and Dominic Wesonga, who have represented Kenya in ODIs. When I expressed interest in getting a jersey, Dominic agreed to send me pictures of his jersey. I liked his jersey and collected it from him. I gave him 2000 shillings, an amount suggested by those Indian players.

Me with players at the Nairobi Gymkhana Club

Cricket pitch at the Nairobi Gymkhana Club

A view of the cricket ground inside the Nairobi Gymkhana Club

Scoreboard at the Nairobi Gymkhana cricket ground

Giraffe Center in Nairobi Kenya is known for its safaris and has no shortage of national parks. In fact, Nairobi is the only capital in the world with a national park. I decided not to visit one, as most of them were expensive and offered multi-day tours, and I didn t want to spend that much time in the wildlife. Instead, I went to the Giraffe Center in Nairobi with Pragya and Rabina. The ticket cost 1500 Kenyan shillings (1000 Indian rupees). In Kenya, matatus - shared vans, usually decorated with portraits of famous people and play rap songs - are the most popular means of public transport. Reaching the Giraffe Center from our hotel required taking five matatus, which cost a total of 150 shillings, and a 2 km walk. The journey back was 90 shillings, suggesting that we didn t find the most efficient route to get there. At the Giraffe Center, we fed giraffes and took photos.

A matatu with a Notorious BIG portrait.

Inside the Giraffe Center

Train ride from Nairobi to Mombasa I took a train from Nairobi to Mombasa. The train is known as the SGR Train, where SGR refers to Standard Gauge Railway. The journey was around 500 km. M-Pesa was the only way to make payment for pre-booking the train ticket, and I didn t have an M-Pesa account. Pragya s friend Mary helped facilitate the payment. I booked a second-class ticket, which cost 1500 shillings (1000 Indian rupees). The train was scheduled to depart from Nairobi at 08:00 hours in the morning and arrive in Mombasa at 14:00 hours. The security check at the station required scanning our bags and having them sniffed by sniffer dogs. I also fell victim to a scam by a security official who offered to help me get my ticket printed, only to later ask me to get him some coffee, which I politely declined. Before boarding the train, I was treated to some stunning views at the Nairobi Terminus station. It was a seating train, but I wished it were a sleeper train, as I was sleep-deprived. The train was neat and clean, with good toilets. The train reached Mombasa on time at around 14:00 hours.

SGR train at Nairobi Terminus.

Interior of the SGR train

Arrival in Mombasa

Mombasa Terminus station.

Mombasa was a bit hotter than Nairobi, with temperatures reaching around 30 degrees Celsius. However, that s not too hot for me, as I am used to higher temperatures in India. I had booked a hostel in the Old Town and was searching for a hitchhike from the Mombasa Terminus station. After trying for more than half an hour, I took a matatu that dropped me 3 km from my hostel for 200 shillings (140 Indian rupees). I tried to hitchhike again but couldn t find a ride. I think I know why I couldn t get a ride in both the cases. In the first case, the Mombasa Terminus was in an isolated place, so most of the vehicles were taxis or matatus while any noncommercial cars were there to pick up friends and family. If the station were in the middle of the city, there would be many more car/truck drivers passing by, thus increasing my possibilities of getting a ride. In the second case, my hostel was at the end of the city, and nobody was going towards that side. In fact, many drivers told me they would love to give me a ride, but they were going in some other direction. Finally, I took a tuktuk for 70 shillings to reach my hostel, Tulia Backpackers. It was 11 USD (1400 shillings) for one night. The balcony gave a nice view of the Indian Ocean. The rooms had fans, but there was no air conditioning. Each bed also had mosquito nets. The place was walking distance of the famous Fort Jesus. Mombasa has had more Islamic influence compared to Nairobi and also has many Hindu temples.

The balcony at Tulia Backpackers Hostel had a nice view of the ocean.

A room inside the hostel with fans and mosquito nets on the beds

Visiting White Sandy Beaches and Getting a Hitchhike Visiting Nyali beach marked my first time ever at a white sand beach. It was like 10 km from the hostel. The next day, I visited Diani Beach, which was 30 km from the hostel. Going to Diani Beach required crossing a river, for which there s a free ferry service every few minutes, followed by taking a matatu to Ukunda and then a tuk-tuk. The journey gave me a glimpse of the beautiful countryside of Kenya.

Nyali beach is a white sand beach

This is the ferry service for crossing the river.

During my return from Diani Beach to the hostel, I was successful in hitchhiking. However, it was only a 4 km ride and not sufficient to reach Ukunda, so I tried to get another ride. When a truck stopped for me, I asked for a ride to Ukunda. Later, I learned that they were going in the same direction as me, so I got off within walking distance from my hostel. The ride was around 30 km. I also learned the difference between a truck ride and a matatu or car ride. For instance, matatus and cars are much faster and cooler due to air conditioning, while trucks tend to be warmer because they lack it. Further, the truck was stopped at many checkpoints by the police for inspections as it carried goods, which is not the case with matatus. Anyways, it was a nice experience, and I am grateful for the ride. I had a nice conversation with the truck drivers about Indian movies and my experiences in Kenya.

Diani beach is a popular beach in Kenya. It is a white sand beach.

Selfie with truck drivers who gave me the free ride

Back to Nairobi I took the SGR train from Mombasa back to Nairobi. This time I took the night train, which departs at 22:00 hours, reaching Nairobi at around 04:00 in the morning. I could not sleep comfortably since the train only had seater seats. I had booked the Zarita Hotel in Nairobi and had already confirmed if they allowed early morning check-in. Usually, hotels have a fixed checkout time, say 11:00 in the morning, and you are not allowed to stay beyond that regardless of the time you checked in. But this hotel checked me in for 24 hours. Here, I paid in US dollars, and the cost was 12 USD.

Almost Got Stuck in Kenya Two days before my scheduled flight from Nairobi back to India, I heard the news that the airports in Kenya were closed due to the strikes. Rabina and Pragya had their flight back to Nepal canceled that day, which left them stuck in Nairobi for two additional days. I called Sahil in India and found out during the conversation that the strike was called off in the evening. It was a big relief for me, and I was fortunate to be able to fly back to India without any changes to my plans.

Newspapers at a stand in Kenya covering news on the airport closure

Experience with locals I had no problems communicating with Kenyans, as everyone I met knew English to an extent that could easily surpass that of big cities in India. Additionally, I learned a few words from Kenya s most popular local language, Swahili, such as Asante, meaning thank you, Jambo for hello, and Karibu for welcome. Knowing a few words in the local language went a long way. I am not sure what s up with haggling in Kenya. It wasn t easy to bring the price of souvenirs down. I bought a fridge magnet for 200 shillings, which was the quoted price. On the other hand, it was much easier to bargain with taxis/tuktuks/motorbikes. I stayed at three hotels/hostels in Kenya. None of them had air conditioners. Two of the places were in Nairobi, and they didn t even have fans in the rooms, while the one in Mombasa had only fans. All of them had good Wi-Fi, except Tulia where the internet overall was a bit shaky. My experience with the hotel staff was great. For instance, we requested that the Nairobi Transit Hotel cancel the included breakfast in order to reduce the room costs, but later realized that it was not a good idea. The hotel allowed us to revert and even offered one of our missing breakfasts during dinner. The staff at Tulia Backpackers in Mombasa facilitated the ticket payment for my train from Mombasa to Nairobi. One of the staff members also gave me a lift to the place where I could catch a matatu to Nyali Beach. They even added an extra tea bag to my tea when I requested it to be stronger.

Food At the Nairobi Transit Hotel, a Spanish omelet with tea was served for breakfast. I noticed that Spanish omelette appeared on the menus of many restaurants, suggesting that it is popular in Kenya. This was my first time having this dish. The milk tea in Kenya, referred to by locals as white tea, is lighter than Indian tea (they don t put a lot of tea leaves).

Spanish Omelette served in breakfast at Nairobi Transit Hotel

I also sampled ugali with eggs. In Mombasa, I visited an Indian restaurant called New Chetna and had a buffet thali there twice.

Ugali with eggs.

Tips for Exchanging Money In Kenya, I exchanged my money at forex shops a couple of times. I received good exchange rates for bills larger than 50 USD. For instance, 1 USD on xe.com was 129 shillings, and I got 128.3 shillings per USD (a total of 12,830 shillings) for two 50 USD notes at an exchange in Nairobi, while 127 shillings, which was the highest rate at the banks. On the other hand, for smaller bills such as a one US dollar note, I would have got 125 shillings. A passport was the only document required for the exchange, and they also provided a receipt. A good piece of advice for travelers is to keep 50 USD or larger bills for exchanging into the local currency while saving the smaller US dollar bills for accommodation, as many hotels and hostels accept payment in US dollars (in addition to Kenyan shillings).

Missed Malindi and Lamu There were more places on my to-visit list in Kenya. But I simply didn t have time to cover them, as I don t like rushing through places, especially in a foreign country where there is a chance of me underestimating the amount of time it takes during transit. I would have liked to visit at least one of Kilifi, Watamu or Malindi beaches. Further, Lamu seemed like a unique place to visit as it has no cars or motorized transport; the only options for transport are boats and donkeys. That s it for now. Meet you in the next one :)

A hot-fix release 1.0.13-1, consisting of two small PRs relative to the last regular CRAN release 1.0.13, just arrived on CRAN. When we prepared 1.0.13, we included a change related to the tightening of the C API of R itself. Sadly, we pinned an expected change to comes with next (minor) release 4.4.2 rather than now next (normal aka major) release 4.5.0 . And now that R 4.4.2 is out (as of two days ago) we accidentally broke building against the header file with that check. Whoops. Bugs happen, and we are truly sorry but this is now addressed in 1.0.13-1. The normal (bi-annual) release cycle will resume with 1.0.14 slated for January. As you can see from the NEWS file of the development branch, we have a number of changes coming. You can safely access that release candidate version, either off the default branch at github or via r-universe artifacts. The list below details all changes, as usual. The only other change concerns the now-mandatory use of Authors@R.

Changes in Rcpp release version 1.0.13-1 (2024-11-01)

• Changes in Rcpp API:
  • Use read-only VECTOR_PTR and STRING_PTR only with with R 4.5.0 or later (Kevin in #1342 fixing #1341)
• Changes in Rcpp Deployment:
  • Authors@R is now used in DESCRIPTION as mandated by CRAN

Thanks to my CRANberries, you can also look at a diff to the previous release Questions, comments etc should go to the rcpp-devel mailing list off the R-Forge page. Bugs reports are welcome at the GitHub issue tracker as well (where one can also search among open or closed issues). If you like this or other open-source work I do, you can sponsor me at GitHub.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

Almost all of my Debian contributions this month were sponsored by Freexian. You can also support my work directly via Liberapay. Ansible I noticed that Ansible had fallen out of Debian testing due to autopkgtest failures. This seemed like a problem worth fixing: in common with many other people, we use Ansible for configuration management at Freexian, and it probably wouldn t make our sysadmins too happy if they upgraded to trixie after its release and found that Ansible was gone. The problems here were really just slogging through test failures in both the ansible-core and ansible packages, but their test suites are large and take a while to run so this took some time. I was able to contribute a few small fixes to various upstreams in the process:

• test: Make git archive prefix fit in 32-bit ssize_t (though upstream went for a different approach)
• test: replace more deprecated assertEquals
• Fix import error on Python 3.13
• Make test_start_daemon_with_no_mock less flaky

This should now get back into testing tomorrow. OpenSSH Martin- ric Racine reported that ssh-audit didn t list the ext-info-s feature as being available in Debian s OpenSSH 9.2 packaging in bookworm, contrary to what OpenSSH upstream said on their specifications page at the time. I spent some time looking into this and realized that upstream was mistakenly saying that implementations of ext-info-c and ext-info-s were added at the same time, while in fact ext-info-s was added rather later. ssh-audit now has clearer output, and the OpenSSH maintainers have corrected their specifications page. I looked into a report of an ssh failure in certain cases when using GSS-API key exchange (which is a Debian patch). Once again, having integration tests was a huge win here: the affected scenario is quite a fiddly one, but I was able to set it up in the test, and thereby make sure it doesn t regress in future. It still took me a couple of hours to get all the details right, but in the past this sort of thing took me much longer with a much lower degree of confidence that the fix was correct. On upstream s advice, I cherry-picked some key exchange fixes needed for big-endian architectures. Python team I packaged python-evalidate, needed for a new upstream version of buildbot. The Python 3.13 transition rolls on. I fixed problems related to it in htmlmin, humanfriendly, postgresfixture (contributed upstream), pylint, python-asyncssh (contributed upstream), python-oauthlib, python3-simpletal, quodlibet, zope.exceptions, and zope.interface. A trickier Python 3.13 issue involved the cgi module. Years ago I ported zope.publisher to the multipart module because cgi.FieldStorage was broken in some situations, and as a result I got a recommendation into Python s dead batteries PEP 594. Unfortunately there turns out to be a name conflict between multipart and python-multipart on PyPI; python-multipart upstream has been working to disentangle this, though we still need to work out what to do in Debian. All the same, I needed to fix python-wadllib and multipart seemed like the best fit; I contributed a port upstream and temporarily copied multipart into Debian s python-wadllib source package to allow its tests to pass. I ll come back and fix this properly once we sort out the multipart vs. python-multipart packaging. tzdata moved some timezone definitions to tzdata-legacy, which has broken a number of packages. I added tzdata-legacy build-dependencies to alembic and python-icalendar to deal with this in those packages, though there are still some other instances of this left. I tracked down an nltk regression that caused build failures in many other packages. I fixed Rust crate versioning issues in pydantic-core, python-bcrypt, and python-maturin (mostly fixed by Peter Michael Green and Jelmer Vernoo , but it needed a little extra work). I fixed other build failures in entrypoints, mayavi2, python-pyvmomi (mostly fixed by Alexandre Detiste, but it needed a little extra work), and python-testing.postgresql (ditto). I fixed python3-simpletal to tolerate future versions of dh-python that will drop their dependency on python3-setuptools. I fixed broken symlinks in python-treq. I removed (build-)depends on python3-pkg-resources from alembic, autopep8, buildbot, celery, flufl.enum, flufl.lock, python-public, python-wadllib (contributed upstream), pyvisa, routes, vulture, and zodbpickle (contributed upstream). I upgraded astroid, asyncpg (fixing a Python 3.13 failure and a build failure), buildbot (noticing an upstream test bug in the process), dnsdiag, frozenlist, netmiko (fixing a Python 3.13 failure), psycopg3, pydantic-settings, pylint, python-asyncssh, python-bleach, python-btrees, python-cytoolz, python-django-pgtrigger, python-django-test-migrations, python-gssapi, python-icalendar, python-json-log-formatter, python-pgbouncer, python-pkginfo, python-plumbum, python-stdlib-list, python-tokenize-rt, python-treq (fixing a Python 3.13 failure), python-typeguard, python-webargs (fixing a build failure), pyupgrade, pyvisa, pyvisa-py (fixing a Python 3.13 failure), toolz, twisted, vulture, waitress (fixing CVE-2024-49768 and CVE-2024-49769), wtf-peewee, wtforms, zodbpickle, zope.exceptions, zope.interface, zope.proxy, zope.security, and zope.testrunner to new upstream versions. I tried to fix a regression in python-scruffy, but I need testing feedback. I requested removal of python-testing.mysqld.

The shared web proxy used on Wikimedia Cloud VPS now has technical support for using arbitrary domains (and not just wmcloud.org subdomains) in proxy names. I think this is a good example of how software slowly evolves over time as new requirements emerge, with each new addition building on top of the previous ones. According to the edit history on Wikitech, the web proxy service has its origins in 2012, although the current idea where you create a proxy and map it to a specific instance and port was only introduced a year later. (Before that, it just directly mapped the subdomain to the VPS instance with the same name). There were some smaller changes in the coming years like the migration to acme-chief for TLS certificate management, but the overall logic stayed very similar until 2020 when the wmcloud.org domain was introduced. That was implemented by adding a config option listing all possible domains, so future domain additions would be as simple as adding the new domain to that list in the configuration. Then the changes start becoming more frequent:

• In 2022, for my Terraform support project, a bunch of logic, including the list of supported backend domains was moved from the frontend code to the backend. This also made it possible to dynamically change which projects can use which domains suffixes for their proxies.
• Then, early this year, I added support for zones restricted to a single project, because we wanted to use the proxy for the *.svc.toolforge.org Toolforge infrastructure domains instead of coming up with a new system for that use case. This also added suport for using different TLS certificates for different domains so that we would not have to have a single giant certificate with all the names.
• Finally, the last step was to add two new features to the proxy system: support for adding a proxy at the apex of a domain, as well as support for domains that are not managed in Designate (the Cloud VPS/OpenStack auth DNS service). In addition, we needed a bit of config to ensure http-01 challenges get routed to the acme-chief instance.

Dacid Brin wrote an interesting article about AI ecosystems and how humans might work with machines on creative projects [1]. Also he s right about influencers being like funghi. Cory Doctorow wrote an interesting post about DRM, coalitions, and cheating [2]. It seems that people like me who want trusted computing to secure their own computers don t fit well in any of the coalitions. The CHERI capability system for using extra hardware to validate jump addresses is an interesting advance in computer science [3]. The lecture is froim the seL4 Summit, this sort of advance in security goes well with a formally proven microkernel. I hope that this becomes a checkbox when ordering a custom RISC-V design. Bunnie wrote an insightful blog post about how the Mossad might have gone about implementing the exploding pager attack [4]. I guess we will see a lot more of this in future, it seems easy to do. Interesting blog post about Control Flow Integrity in the V8 engine of Chrome [5]. Interesting blog post about the new mseal() syscall which can be used by CFI among other things [6]. This is the Linux kernel documentation about the Control-flow Enforcement Technology (CET) Shadow Stack [7]. Unfortunately not enabled in Debian/Unstable yet. ARM added support for Branch Target Identification in version 8.5 of the architecture [8]. The CEO of Automatic has taken his dispute with WPEngine to an epic level, this video catalogues it, I wonder what is wrong with him [9]. NuShell is an interesting development in shell technology which runs on Linux and Windows [10]. Interesting article about making a computer game without coding using ML [11]. I doubt that it would be a good game, but maybe educational for kids. Krebs has an insightful article about location tracking by phones which is surprisingly accurate [12]. He has provided information on how to opt out of some of it on Android, but we need legislative action! Interesting YouTube video about how to make a 20kW microwave oven and what it can do [13]. Don t do this at home, or anywhere else! The Void editor is an interesting project, a fork of VSCode that supports DIRECT connections to LLM systems where you don t have their server acting as a middle-man and potentially snooping [14].

• [1] https://tinyurl.com/26geg4az
• [2] https://tinyurl.com/29n4hyvv
• [3] https://www.youtube.com/watch?v=VcufX8hZ5-o
• [4] https://tinyurl.com/2beb7ala
• [5] https://v8.dev/blog/control-flow-integrity
• [6] https://tinyurl.com/26p8hlcr
• [7] https://docs.kernel.org/next/x86/shstk.html
• [8] https://tinyurl.com/26ffcrho
• [9] https://www.youtube.com/watch?v=v-imW24OXLY
• [10] https://www.youtube.com/watch?v=zoX_S6d-XU4
• [11] https://tinyurl.com/ysqe79q7
• [12] https://tinyurl.com/258r74cl
• [13] https://www.youtube.com/watch?v=mg79n_ndR68
• [14] https://tinyurl.com/2xtu7kvv

Another pure maintenance release 0.2.7 of the gcbd package is now on CRAN. The gcbd proposes a benchmarking framework for LAPACK and BLAS operations (as the library can exchanged in a plug-and-play sense on suitable OSs) and records result in local database. Its original motivation was to also compare to GPU-based operations. However, as it is both challenging to keep CUDA working packages on CRAN providing the basic functionality appear to come and go so testing the GPU feature can be challenging. The main point of gcbd is now to actually demonstrate that yes indeed we can just swap BLAS/LAPACK libraries without any change to R, or R packages. The configure / rebuild R for xyz often seen with xyz being Goto or MKL is simply plain wrong: you really can just swap them (on proper operating systems, and R configs see the package vignette for more). But nomatter how often we aim to correct this record, it invariably raises its head another time. This release accommodates a CRAN change request as we were referencing the (now only suggested) package gputools. As hinted in the previous paragraph, it was once on CRAN but is not right now so we adjusted our reference. CRANberries also provides a diffstat report for the latest release. If you like this or other open-source work I do, you can sponsor me at GitHub.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.

The Announcement Late last month there was an announcement of a severity 9.9 vulnerability allowing remote code execution that affects all GNU/Linux systems (plus others) [1]. For something to affect all Linux systems that would have to be either a kernel issue or a sshd issue. The announcement included complaints about the lack of response of vendors and And YES: I LOVE hyping the sh1t out of this stuff because apparently sensationalism is the only language that forces these people to fix . He seems to have a different experience to me of reporting bugs, I have had plenty of success getting bugs fixed without hyping them. I just report the bug, wait a while, and it gets fixed. I have reported potential security bugs without even bothering to try and prove that they were exploitable (any situation where you can make a program crash is potentially exploitable), I just report it and it gets fixed. I was very dubious about his ability to determine how serious a bug is and to accurately report it so this wasn t a situation where I was waiting for it to be disclosed to discover if it affected me. I was quite confident that my systems wouldn t be at any risk. Analysis Not All Linux Systems Run CUPS When it was published my opinion was proven to be correct, it turned out to be a series of CUPS bugs [2]. To describe that as all GNU/Linux systems (plus others) seems like a vast overstatement, maybe a good thing to say if you want to be a TikTok influencer but not if you want to be known for computer security work. For the Debian distribution the cups-browsed package (which seems to be the main exploitable one) is recommended by cups-daemon, as I have my Debian systems configured to not install recommended packages by default that means that it wasn t installed on any of my systems. Also the vast majority of my systems don t do printing and therefore don t have any part of CUPS installed. CUPS vs NAT The next issue is that in Australia most home ISPs don t have IPv6 enabled and CUPS doesn t do the things needed to allow receiving connections from the outside world via NAT with IPv4. If inbound port 631 is blocked on both TCP and USP as is the default on Australian home Internet or if there is a correctly configured firewall in place then the network is safe from attack. There is a feature called uPnP port forwarding [3] to allow server programs to ask a router to send inbound connections to them, this is apparently usually turned off by default in router configuration. If it is enabled then there are Debian packages of software to manage this, the miniupnpc package has the client (which can request NAT changes on the router) [4]. That package is not installed on any of my systems and for my home network I don t use a router that runs uPnP. The only program I knowingly run that uses uPnP is Warzone2100 and as I don t play network games that doesn t happen. Also as an aside in version 4.4.2-1 of warzone2100 in Debian and Ubuntu I made it use Bubblewrap to run the game in a container. So a Remote Code Execution bug in Warzone 2100 won t be an immediate win for an attacker (exploits via X11 or Wayland are another issue). MAC Systems Debian has had AppArmor enabled by default since Buster was released in 2019 [5]. There are claims that AppArmor will stop this exploit from doing anything bad. To check SE Linux access I first use the semanage fcontext command to check the context of the binary, cupsd_exec_t means that the daemon runs as cupsd_t. Then I checked what file access is granted with the sesearch program, mostly just access to temporary files, cupsd config files, the faillog, the Kerberos cache files (not used on the Kerberos client systems I run), Samba run files (might be a possibility of exploiting something there), and the security_t used for interfacing with kernel security infrastructure. I then checked the access to the security class and found that it is permitted to check contexts and access-vectors not access that can be harmful. The next test was to use sesearch to discover what capabilities are granted, which unfortunately includes the sys_admin capability, that is a capability that allows many sysadmin tasks that could be harmful (I just checked the Fedora source and Fedora 42 has the same access). Whether the sys_admin capability can be used to do bad things with the limited access cupsd_t has to device nodes etc is not clear. But this access is undesirable. So the SE Linux policy in Debian and Fedora will stop cupsd_t from writing SETUID programs that can be used by random users for root access and stop it from writing to /etc/shadow etc. But the sys_admin capability might allow it to do hostile things and I have already uploaded a changed policy to Debian/Unstable to remove that. The sys_rawio capability also looked concerning but it s apparently needed to probe for USB printers and as the domain has no access to block devices it is otherwise harmless. Below are the commands I used to discover what the policy allows and the output from them.

# semanage fcontext -l grep bin/cups-browsed
/usr/bin/cups-browsed                              regular file       system_u:object_r:cupsd_exec_t:s0 
# sesearch -A -s cupsd_t -c file -p write
allow cupsd_t cupsd_interface_t:file   append create execute execute_no_trans getattr ioctl link lock map open read rename setattr unlink write  ;
allow cupsd_t cupsd_lock_t:file   append create getattr ioctl link lock open read rename setattr unlink write  ;
allow cupsd_t cupsd_log_t:file   append create getattr ioctl link lock open read rename setattr unlink write  ;
allow cupsd_t cupsd_runtime_t:file   append create getattr ioctl link lock open read rename setattr unlink write  ;
allow cupsd_t cupsd_rw_etc_t:file   append create getattr ioctl link lock open read rename setattr unlink write  ;
allow cupsd_t cupsd_t:file   append create getattr ioctl link lock open read rename setattr unlink write  ;
allow cupsd_t cupsd_tmp_t:file   append create getattr ioctl link lock open read rename setattr unlink write  ;
allow cupsd_t faillog_t:file   append getattr ioctl lock open read write  ;
allow cupsd_t init_tmpfs_t:file   append getattr ioctl lock read write  ;
allow cupsd_t krb5_host_rcache_t:file   append create getattr ioctl link lock open read rename setattr unlink write  ; [ allow_kerberos ]:True
allow cupsd_t print_spool_t:file   append create getattr ioctl link lock open read relabelfrom relabelto rename setattr unlink write  ;
allow cupsd_t samba_var_t:file   append getattr ioctl lock open read write  ;
allow cupsd_t security_t:file   append getattr ioctl lock open read write  ;
allow cupsd_t security_t:file   append getattr ioctl lock open read write  ; [ allow_kerberos ]:True
allow cupsd_t usbfs_t:file   append getattr ioctl lock open read write  ;
# sesearch -A -s cupsd_t -c security
allow cupsd_t security_t:security check_context; [ allow_kerberos ]:True
allow cupsd_t security_t:security   check_context compute_av  ;
# sesearch -A -s cupsd_t -c capability
allow cupsd_t cupsd_t:capability net_bind_service; [ allow_ypbind ]:True
allow cupsd_t cupsd_t:capability   audit_write chown dac_override dac_read_search fowner fsetid ipc_lock kill net_bind_service setgid setuid sys_admin sys_rawio sys_resource sys_tty_config  ;
# sesearch -A -s cupsd_t -c capability2
allow cupsd_t cupsd_t:capability2   block_suspend wake_alarm  ;
# sesearch -A -s cupsd_t -c blk_file

Conclusion This is an example of how not to handle security issues. Some degree of promotion is acceptable but this is very excessive and will result in people not taking security announcements seriously in future. I wonder if this is even a good career move by the researcher in question, will enough people believe that they actually did something good in this that it outweighs the number of people who think it s misleading at best?

• [1] https://threadreaderapp.com/thread/1838169889330135132.html
• [2] https://tinyurl.com/26rjd5ex
• [3] https://tinyurl.com/2ckyvpyq
• [4] https://packages.debian.org/sid/miniupnpc
• [5] https://wiki.debian.org/AppArmor/HowToUse

Russell wrote a great comment on my last post (thanks!):

What benefits do these things offer when a general purpose computer can do so many things nowadays? Is there a USB keyboard that you can connect to a laptop or phone to do these things? I presume that all recent phones have the compute power to do all the synthesis you need if you have the right software. Is it just a lack of software and infrastructure for doing it on laptops/phones that makes synthesisers still viable?

I've decided to turn my response into a post of its own. The issue is definitely not compute power. You can indeed attach a USB keyboard to a computer and use a plethora of software synthesisers, including very faithful emulations of all the popular classics. The raw compute power of modern hardware synths is comparatively small: I ve been told the modern Korg digital synths are on a par with a raspberry pi. I ve seen some DSPs which are 32 bit ARMs, and other tools which are roughly equivalent to arduinos. I can think of four reasons hardware synths remain popular with some despite the above:

1. As I touched on in my original synth post, computing dominates my life outside of music already. I really wanted something separate from that to keep mental distance from work.
2. Synths have hard real-time requirements. They don't have raw power in compute terms, but they absolutely have to do their job within microseconds of being instructed to, with no exceptions. Linux still has a long way to go for hard real-time.
3. The Linux audio ecosystem is complex. Dealing with pipewire, pulseaudio, jack, alsa, oss, and anything else I've forgotten, as well as their failure modes, is too time consuming.
4. The last point is to do with creativity and inspiration. A good synth is more than the sum of its parts: it's an instrument, carefully designed and its components integrated by musically-minded people who have set out to create something to inspire. There are plenty of synths which aren't good instruments, but have loads of features: they re boxes of "stuff". Good synths can't do it all: they often have limitations which you have to respond to, work around or with, creatively. This was expressed better than I could by Trent Reznor in the video archetype of a synthesiser:

A new minor release of the drat package arrived on CRAN today, which is just over a year since the previous release. drat stands for drat R Archive Template, and helps with easy-to-create and easy-to-use repositories for R packages. Since its inception in early 2015 it has found reasonably widespread adoption among R users because repositories with marked releases is the better way to distribute code. Because for once it really is as your mother told you: Friends don t let friends install random git commit snapshots. Properly rolled-up releases it is. Just how CRAN shows us: a model that has demonstrated for over two-and-a-half decades how to do this. And you can too: drat is easy to use, documented by six vignettes and just works. Detailed information about drat is at its documentation site. That said, and these days , if you mainly care about github code then r-universe is there too, also offering binaries its makes and all that jazz. But sometimes you just want to, or need to, roll a local repository and drat can help you there. This release contains a small PR (made by Arne Holmin just after the previous release) adding support for an OSflacour variable (helpful for macOS). We also corrected an issue with one test file being insufficiently careful of using git2r only when installed, and as usual did a round of maintenance for the package concerning both continuous integration and documentation. The NEWS file summarises the release as follows:

Changes in drat version 0.2.5 (2024-10-21)

• Function insertPackage has a new optional argument OSflavour (Arne Holmin in #142)
• A test file conditions correctly about git2r being present (Dirk)
• Several smaller packaging updates and enhancements to continuous integration and documentation have been added (Dirk)

Courtesy of my CRANberries, there is a comparison to the previous release. More detailed information is on the drat page as well as at the documentation site. If you like this or other open-source work I do, you can sponsor me at GitHub.

This post by Dirk Eddelbuettel originated on his Thinking inside the box blog. Please report excessive re-aggregation in third-party for-profit settings.