Search Results: "ron"

29 May 2020

Thomas Goirand: A quick look into Storcli packaging horror

So, Megacli is to be replaced by Storcli, both being proprietary tools for configuring RAID cards from LSI. So I went to download what s provided by Lenovo, available here:
https://support.lenovo.com/fr/en/downloads/ds041827 It s very annoying, because they force users to download a .zip file containing a deb file, instead of providing a Debian repository. Well, ok, though at least there s a deb file there. Let s have a look what s using my favorite tool before installing (ie: let s run Lintian).
Then it s a horror story. Not only there s obvious packaging wrong, like the package provide stuff in /opt, and all is statically linked and provide embedded copies of libm and ncurses, or even the package is marked arch: all instead of arch: amd64 (in fact, the package contains both i386 and amd64 arch files ), but there s also some really wrong things going on:
E: storcli: arch-independent-package-contains-binary-or-object opt/MegaRAID/storcli/storcli
E: storcli: embedded-library opt/MegaRAID/storcli/storcli: libm
E: storcli: embedded-library opt/MegaRAID/storcli/storcli: ncurses
E: storcli: statically-linked-binary opt/MegaRAID/storcli/storcli
E: storcli: arch-independent-package-contains-binary-or-object opt/MegaRAID/storcli/storcli64
E: storcli: embedded-library opt/MegaRAID/storcli/storcli64: libm
E: storcli: embedded-library use no-tag-display-limit to see all (or pipe to a file/program)
E: storcli: statically-linked-binary opt/MegaRAID/storcli/storcli64
E: storcli: changelog-file-missing-in-native-package
E: storcli: control-file-has-bad-permissions postinst 0775 != 0755
E: storcli: control-file-has-bad-owner postinst asif/asif != root/root
E: storcli: control-file-has-bad-permissions preinst 0775 != 0755
E: storcli: control-file-has-bad-owner preinst asif/asif != root/root
E: storcli: no-copyright-file
E: storcli: extended-description-is-empty
W: storcli: essential-no-not-needed
W: storcli: unknown-section storcli
E: storcli: depends-on-essential-package-without-using-version depends: bash
E: storcli: wrong-file-owner-uid-or-gid opt/ 1000/1000
W: storcli: non-standard-dir-perm opt/ 0775 != 0755
E: storcli: wrong-file-owner-uid-or-gid opt/MegaRAID/ 1000/1000
E: storcli: dir-or-file-in-opt opt/MegaRAID/
W: storcli: non-standard-dir-perm opt/MegaRAID/ 0775 != 0755
E: storcli: wrong-file-owner-uid-or-gid opt/MegaRAID/storcli/ 1000/1000
E: storcli: dir-or-file-in-opt opt/MegaRAID/storcli/
W: storcli: non-standard-dir-perm opt/MegaRAID/storcli/ 0775 != 0755
E: storcli: wrong-file-owner-uid-or-gid use no-tag-display-limit to see all (or pipe to a file/program)
E: storcli: dir-or-file-in-opt opt/MegaRAID/storcli/storcli
E: storcli: dir-or-file-in-opt use no-tag-display-limit to see all (or pipe to a file/program) Some of the above are grave security problems, like wrong Unix mode for folders, even with the preinst script installed as non-root.
I always wonder why this type of tool needs to be proprietary. They clearly don t know how to get packaging right, so they d better just provide the source code, and let us (the Debian community) do the work for them. I don t think there s any secret that they are keeping by hiding how to configure the cards, so it s not in the vendor s interest to keep everything closed. Or maybe they are just hiding really bad code in there, that they are ashamed to share? In any way, they d better not provide any package than this pile of dirt (and I m trying to stay polite here ).

Keith Packard: picolibc-string-float

Float/String Conversion in Picolibc Exact conversion between strings and floats seems like a fairly straightforward problem. There are two related problems:
  1. String to Float conversion. In this case, the goal is to construct the floating point number which most closely approximates the number represented by the string.
  2. Float to String conversion. Here, the goal is to generate the shortest string which, when fed back into the String to Float conversion code, exactly reproduces the original value.
When linked together, getting from float to string and back to float is a round trip , and an exact pair of algorithms does this for every floating point value. Solutions for both directions were published in the proceedings of the ACM SIGPLAN 1990 conference on Programming language design and implementation, with the string-to-float version written by William Clinger and the float-to-string version written by Guy Steele and Jon White. These solutions rely on very high precision integer arithmetic to get every case correct, with float-to-string requiring up to 1050 bits for the 64-bit IEEE floating point format. That's a lot of bits. Newlib Float/String Conversion The original newlib code, written in 1998 by David M. Gay, has arbitrary-precision numeric code for these functions to get exact results. However, it has the disadvantages of performing numerous memory allocations, consuming considerable space for the code, and taking a long time for conversions. The first disadvantage, using malloc during conversion, ended up causing a number of CVEs because the results of malloc were not being checked. That's bad on all platforms, but especially bad for embedded systems where reading and writing through NULL pointers may have unknown effects. Upstream newlib applied a quick fix to check the allocations and call abort. Again, on platforms with an OS, that at least provides a way to shut down the program and let the operating environment figure out what to do next. On tiny embedded systems, there may not be any way to log an error message or even restart the system. Ok, so we want to get rid of the calls to abort and have the error reported back through the API call which caused the problem. That's got two issues, one mere technical work, and another mere re-interpretation of specifications. Let's review the specification issue. The libc APIs involved here are: Input: Output: Scanf and printf are both documented to set errno to ENOMEM when they run out of memory, but none of the other functions takes that possibility into account. So we'll make some stuff up and hope it works out: Now, looking back at the technical challenge. That's a simple matter of inserting checks at each allocation, or call which may result in an allocation, and reporting failure back up the call stack, unwinding any intermediate state to avoid leaking memory. Testing Every Possible Allocation Failure There are a lot of allocation calls in the newlib code. And the call stack can get pretty deep. A simple visual inspection of the code didn't seem sufficient to me to validate the allocation checking code. So I instrumented malloc, making it count the number of allocations and fail at a specific one. Now I can count the total number of allocations done over the entire test suite run for each API involved and then run the test suite that many times, failing each allocation in turn and checking to make sure we recover correctly. By that, I mean: There were about 60000 allocations to track, so I ran the test suite that many times, which (with the added malloc tracing enabled) took about 12 hours. Bits Pushed to the Repository With the testing complete, I'm reasonably confident that the code is now working, and that these CVEs are more completely squashed. If someone is interested in back-porting the newlib fixes upstream to newlib, that would be awesome. It's not completely trivial as this part of picolibc has diverged a bit due to the elimination of the reent structure. Picolibc's Tinystdio Float/String Conversion Picolibc contains a complete replacement for stdio which was originally adopted from avr libc. That's a stdio implementation designed to run on 8-bit Atmel processors and focuses on very limited memory use and small code size. It does this while maintaining surprisingly complete support for C99 printf and scanf support. However, it also does this without any arbitrary precision arithmetic, which means it doesn't get the right answer all of the time. For most embedded systems, this is usually a good trade off -- floating point input and output are likely to be largely used for diagnostics and debugging, so mostly correct answers are probably sufficient. The original avr-libc code only supports 32-bit floats, as that's all the ABI on those processors has. I extended that to 64-, 80- and 128- bit floats to cover double and long double on x86 and RISC-V processors. Then I spent a bunch of time adjusting the code to get it to more accurately support C99 standards. Tinystdio also had strtod support, but it was missing ecvt, fcvt and gcvt. For those, picolibc was just falling back to the old newlib code, which introduced all of the memory allocation issues we've just read about. Fixing that so that tinystdio was self-contained and did ecvt, fcvt and gcvt internally required writing those functions in terms of the float-to-string primitives already provided in tinystdio to support printf. gcvt is most easily supported by just calling sprintf. Once complete, the default picolibc build, using tinystdio, no longer does any memory allocation for float/string conversions.

28 May 2020

Antoine Beaupr : Upgrading my home server uplink

For more than a few decades now (!), I've been running my own server. First it was just my old Pentium 1 squatting on university networks, but eventually grew into a real server somewhere at the dawn of the millenia. Apart from the university days, the server was mostly hosted over ADSL links, first a handful of megabits, up to the current 25 Mbps down, 6 Mbps up that the Bell Canada network seems to allow to its resellers (currently Teksavvy Internet, or TSI).

Why change? Obviously, this speed is showing its age, and especially in this age of Pandemia where everyone is on videoconferencing all the time. But it's also inconvenient when I need to upload large files on the network. I also host a variety of services on this network, and I always worry that any idiot can (rather trivially) DoS my server, so I often feel I should pack a little more punch at home (although I have no illusions about my capacity of resisting any sort of DoS attack at home of course). Also, the idea of having gigabit links at home brings back the idea of the original internet, that everyone on the internet is a "peer". "Client" and "servers" are just a technical distinction and everyone should be able to run a server.

Requirements So I'm shopping for a replacement. The requirements are:
  1. higher speed than 25/6, preferably 100mbps down, 30mbps up, or more. ideally 1gbps symmetric.
  2. static or near-static IP address: I run a DNS server with its IP in the glue records (although the latter could possibly be relaxed). ideally a /29 or more.
  3. all ports open: I run an SMTP server (incoming and outgoing) along with a webserver and other experiments. ideally, no firewall or policy should be blocking me from hosting stuff, unless there's an attack or security issue, obviously.
  4. clean IP address: the SMTP server needs to have a good reputation, so the IP address should not be in a "residential space" pool.
  5. IPv6 support: TSI offers IPv6 support, but it is buggy (I frequently have to restart the IPv6 interface on the router because the delegated block stops routing, and they haven't been able to figure out the problem). ideally, a /56.
  6. less than 100$/mth, ideally close to the current 60$/mth I pay.
(All amounts in $CAD.)

Contestants I wrote a similar message asking major ISPs in my city for those services, including business service if necessary: I have not contacted those providers:
  • Bell Canada: i have sworn, two decades ago, never to do business with that company ever again. They have a near-monopoly on almost all telcos in Canada and I want to give them as little money as possible.
  • Videotron: I know for a fact they do not allow servers on their network, and their IPv6 has been in beta for so long it has become somewhat of a joke now
I might have forgotten some, let me know if you're in the area and have a good recommendation. I'll update this post with findings as they come in. Keep in mind that I am in a major Canadian city, less than a kilometer from a major telco exchange site, so it's not like I'm in a rural community. This should just work.

TSI First answer from TSI was "we do not provide 30mbps upload on residential services", even though they seem to have that package on their website. They confirmed that they "don't have a option more than 10 mbps upload." TSI were the first to respond, within 24h.

Oricom They offer a 100/30 link for 65$ plus 25$ for a static IP. No IPv6 yet, unlikely to come soon. No services blocked, they have their own PoP within Videotron's datacenters so clients come out from their IP address space. I can confirm that the IP is fairly static from the office. Oricom were the second to respond, within 24h, but required a phone call instead of an email exchange. Responded within 6 hours after leaving a voicemail.

Ebox Ebox claims my neighborhood supports 400mbps down, but offered me a 100/30 package with 350Go bandwidth per month for 54.95$/mth or unlimited for 65$/mth. Many ports are blocked, which makes it impossible for me to use their service:
  • port 25 blocked incoming
  • port 25 filtered outgoing (only allowed to their servers)
  • port 53 blocked incoming (!)
No static IP addressing, shared dynamic space so no garantee on reputation. IPv6 only on DSL, so no high speed IPv6. Ebox took the longest to respond, about 48 hours.

Beanfield / Openface Even though they have a really interesting service (50$/mth for unlimited 1gbps), they are not in my building. I did try to contact them over chat, they told me to call, and I left a message. They responded saying they mostly offer business services for now, no residential in Montreal.

27 May 2020

Kees Cook: security things in Linux v5.5

Previously: v5.4. I got a bit behind on this blog post series! Let s get caught up. Here are a bunch of security things I found interesting in the Linux kernel v5.5 release: restrict perf_event_open() from LSM
Given the recurring flaws in the perf subsystem, there has been a strong desire to be able to entirely disable the interface. While the kernel.perf_event_paranoid sysctl knob has existed for a while, attempts to extend its control to block all perf_event_open() calls have failed in the past. Distribution kernels have carried the rejected sysctl patch for many years, but now Joel Fernandes has implemented a solution that was deemed acceptable: instead of extending the sysctl, add LSM hooks so that LSMs (e.g. SELinux, Apparmor, etc) can make these choices as part of their overall system policy. generic fast full refcount_t
Will Deacon took the recent refcount_t hardening work for both x86 and arm64 and distilled the implementations into a single architecture-agnostic C version. The result was almost as fast as the x86 assembly version, but it covered more cases (e.g. increment-from-zero), and is now available by default for all architectures. (There is no longer any Kconfig associated with refcount_t; the use of the primitive provides full coverage.) linker script cleanup for exception tables
When Rick Edgecombe presented his work on building Execute-Only memory under a hypervisor, he noted a region of memory that the kernel was attempting to read directly (instead of execute). He rearranged things for his x86-only patch series to work around the issue. Since I d just been working in this area, I realized the root cause of this problem was the location of the exception table (which is strictly a lookup table and is never executed) and built a fix for the issue and applied it to all architectures, since it turns out the exception tables for almost all architectures are just a data table. Hopefully this will help clear the path for more Execute-Only memory work on all architectures. In the process of this, I also updated the section fill bytes on x86 to be a trap (0xCC, int3), instead of a NOP instruction so functions would need to be targeted more precisely by attacks. KASLR for 32-bit PowerPC
Joining many other architectures, Jason Yan added kernel text base-address offset randomization (KASLR) to 32-bit PowerPC. seccomp for RISC-V
After a bit of long road, David Abdurachmanov has added seccomp support to the RISC-V architecture. The series uncovered some more corner cases in the seccomp self tests code, which is always nice since then we get to make it more robust for the future! seccomp USER_NOTIF continuation
When the seccomp SECCOMP_RET_USER_NOTIF interface was added, it seemed like it would only be used in very limited conditions, so the idea of needing to handle normal requests didn t seem very onerous. However, since then, it has become clear that the overhead of a monitor process needing to perform lots of normal open() calls on behalf of the monitored process started to look more and more slow and fragile. To deal with this, it became clear that there needed to be a way for the USER_NOTIF interface to indicate that seccomp should just continue as normal and allow the syscall without any special handling. Christian Brauner implemented SECCOMP_USER_NOTIF_FLAG_CONTINUE to get this done. It comes with a bit of a disclaimer due to the chance that monitors may use it in places where ToCToU is a risk, and for possible conflicts with SECCOMP_RET_TRACE. But overall, this is a net win for container monitoring tools. EFI_RNG_PROTOCOL for x86
Some EFI systems provide a Random Number Generator interface, which is useful for gaining some entropy in the kernel during very early boot. The arm64 boot stub has been using this for a while now, but Dominik Brodowski has now added support for x86 to do the same. This entropy is useful for kernel subsystems performing very earlier initialization whre random numbers are needed (like randomizing aspects of the SLUB memory allocator). FORTIFY_SOURCE for MIPS
As has been enabled on many other architectures, Dmitry Korotin got MIPS building with CONFIG_FORTIFY_SOURCE, so compile-time (and some run-time) buffer overflows during calls to the memcpy() and strcpy() families of functions will be detected. limit copy_ to,from _user() size to INT_MAX
As done for VFS, vsnprintf(), and strscpy(), I went ahead and limited the size of copy_to_user() and copy_from_user() calls to INT_MAX in order to catch any weird overflows in size calculations. Other things
Alexander Popov pointed out some more v5.5 features that I missed in this blog post. I m repeating them here, with some minor edits/clarifications. Thank you Alexander! Edit: added Alexander Popov s notes That s it for v5.5! Let me know if there s anything else that I should call out here. Next up: Linux v5.6.

2020, Kees Cook. This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 License.
Creative Commons License

Russ Allbery: Review: Middlegame

Review: Middlegame, by Seanan McGuire
Publisher: Tor
Copyright: May 2019
ISBN: 1-250-19551-9
Format: Kindle
Pages: 528
Roger and Dodger are cuckoo children, alchemical constructs created by other alchemical constructs masquerading as humans. They are halves of the primal force of the universe, the Doctrine of Ethos (which is not what the Doctrine of Ethos is, but that is one of my lesser problems with this book), divided into language and math and kept separate to properly mature. In this case, separate means being adopted by families on opposite coasts of the United States, ignorant of each other's existence and closely monitored by agents Reed controls. None of that prevents Roger and Dodger from becoming each other's invisible friends at the age of seven, effortlessly communicating psychically even though they've never met. That could have been the start of an enjoyable story that hearkened back to an earlier age of science fiction: the secret science experiments discover that they have more power than their creators expected, form a clandestine alliance, and fight back against the people who are trying to control them. I have fond memories of Escape to Witch Mountain and would have happily read that book. Unfortunately, that isn't the story McGuire wanted to tell. The story she told involves ripping Roger and Dodger apart, breaking Dodger, and turning Roger into an abusive asshole. Whooboy, where to start. This book made me very angry, in a way that I would not have been if it didn't contain the bones of a much better novel. Four of them, to be precise: four other books that would have felt less gratuitously cruel and less apparently oblivious to just how bad Roger's behavior is. There are some things to like. One of them is that the structure of this book is clever. I can't tell you how it's clever because the structure doesn't become clear until more than halfway through and it completely changes the story in a way that would be a massive spoiler. But it's an interesting spin on an old idea, one that gave Roger and Dodger a type of agency in the story that has far-ranging implications. I enjoyed thinking about it. That leads me to another element I liked: Erin. She makes only fleeting appearances until well into the story, but I thought she competed with Dodger for being the best character of the book. The second of the better novels I saw in the bones of Middlegame was the same story told from Erin's perspective. I found myself guessing at her motives and paying close attention to hints that led to a story with a much different emotional tone. Viewing the ending of the book through her eyes instead of Roger and Dodger's puts it in a different, more complicated, and more thought-provoking light. Unfortunately, she's not McGuire's protagonist. She instead is one of the monsters of this book, which leads to my first, although not my strongest, complaint. It felt like McGuire was trying too hard to write horror, packing Middlegame with the visuals of horror movies without the underlying structure required to make them effective. I'm not a fan of horror personally, so to some extent I'm grateful that the horrific elements were ineffective, but it makes for some frustratingly bad writing. For example, one of the longest horror scenes in the book features Erin, and should be a defining moment for the character. Unfortunately, it's so heavy on visuals and so focused on what McGuire wants the reader to be thinking that it doesn't show any of the psychology underlying Erin's decisions. The camera is pointed the wrong way; all the interesting storytelling work, moral complexity, and world-building darkness is happening in the character we don't get to see. And, on top of that, McGuire overuses foreshadowing so much that it robs the scene of suspense and terror. Again, I'm partly grateful, since I don't read books for suspense and terror, but it means the scene does only a fraction of the work it could. This problem of trying too hard extends to the writing. McGuire has a bit of a tendency in all of her books to overdo the descriptions, but is usually saved by narrative momentum. Unfortunately, that's not true here, and her prose often seems overwrought. She also resorts to this style of description, which never fails to irritate me:
The thought has barely formed when a different shape looms over him, grinning widely enough to show every tooth in its head. They are even, white, and perfect, and yet he somehow can't stop himself from thinking there's something wrong with them, that they're mismatched, that this assortment of teeth was never meant to share a single jaw, a single terrible smile.
This isn't effective. This is telling the reader how they're supposed to feel about the thing you're describing, without doing the work of writing a description that makes them feel that way. (Also, you may see what I mean by overwrought.) That leads me to my next complaint: the villains. My problem is not so much with Leigh, who I thought was an adequate monster, if a bit single-note. There's some thought and depth behind her arguments with Reed, a few hints of her own motives that were more convincing for not being fully shown. The descriptions of how dangerous she is were reasonably effective. She's a good villain for this type of dark fantasy story where the world is dangerous and full of terrors (and reminded me of some of the villains from McGuire's October Daye series). Reed, though, is a storytelling train wreck. The Big Bad of the novel is the least interesting character in it. He is a stuffed tailcoat full of malicious incompetence who is only dangerous because the author proclaims him to be. It only adds insult to injury that he kills off a far more nuanced and creative villain before the novel starts, replacing her ambiguous goals with Snidely Whiplash mustache-twirling. The reader has to suffer through extended scenes focused on him as he brags, monologues, and obsesses over his eventual victory without an ounce of nuance or subtlety. Worse is the dynamic between him and Leigh, which is only one symptom of the problem with Middlegame that made me the most angry: the degree to this book oozes patriarchy. Every man in this book, including the supposed hero, orders around the women, who are forced in various ways to obey. This is the most obvious between Leigh and Reed, but it's the most toxic, if generally more subtle, between Roger and Dodger. Dodger is great. I had absolutely no trouble identifying with and rooting for her as a character. The nasty things that McGuire does to her over the course of the book (and wow does that never let up) made me like her more when she tenaciously refuses to give up. Dodger is the math component of the Doctrine of Ethos, and early in the book I thought McGuire handled that well, particularly given how difficult it is to write a preternatural genius. Towards the end of this book, her math sadly turns into a very non-mathematical magic (more on this in a moment), but her character holds all the way through. It felt like she carved her personality out of this story through sheer force of will and clung to it despite the plot. I wanted to rescue her from this novel and put her into a better book, such as the one in which her college friends (who are great; McGuire is very good at female friendships when she writes them) stage an intervention, kick a few people out of her life, and convince her to trust them. Unfortunately, Dodger is, by authorial fiat, half of a bound pair, and the other half of that pair is Roger, who is the sort of nice guy everyone likes and thinks is sweet and charming until he turns into an emotional trap door right when you need him the most and dumps you into the ocean to drown. And then somehow makes you do all the work of helping him feel better about his betrayal. The most egregious (and most patriarchal) thing Roger does in this book is late in the book and a fairly substantial spoiler, so I can't rant about that properly. But even before that, Roger keeps doing the the same damn emotional abandonment trick, and the book is heavily invested into justifying it and making excuses for him. Excuses that, I should note, are not made for Dodger; her failings are due to her mistakes and weaknesses, whereas Roger's are natural reactions to outside forces. I got very, very tired of this, and I'm upset by how little awareness the narrative voice showed for how dysfunctional and abusive this relationship is. The solution is always for Dodger to reunite with Roger; it's built into the structure of the story. I have a weakness for the soul-bound pair, in part from reading a lot of Mercedes Lackey at an impressionable age, but one of the dangerous pitfalls of the concept is that the characters then have to have an almost flawless relationship. If not, it can turn abusive very quickly, since the characters by definition cannot leave each other. It's essentially coercive, so as soon as the relationship shows a dark side, the author needs to be extremely careful. McGuire was not. There is an attempted partial patch, late in the book, for the patriarchal structure. One of the characters complains about it, and another says that the gender of the language and math pairs is random and went either way in other pairs. Given that both of the pairs that we meet in this story have the same male-dominant gender dynamic, what I took from this is that McGuire realized there was a problem but wasn't able to fix it. (I'm also reminded of David R. Henry's old line that it's never a good sign when the characters start complaining about the plot.) The structural problems are all the more frustrating because I think there were ways out of them. Roger is supposedly the embodiment of language, not that you'd be able to tell from most scenes in this novel. For reasons that I do not understand, McGuire expressed that as a love of words: lexicography, translation, and synonyms. This makes no sense to me. Those are some of the more structured and rules-based (and hence mathematical) parts of language. If Roger had instead been focused on stories collecting them, telling them, and understanding why and how they're told he would have had a clearer contrast with Dodger. More importantly, it would have solved the plot problem that McGuire solved with a nasty bit of patriarchy. So much could have been done with Dodger building a structure of math around Roger's story-based expansion of the possible, and it would have grounded Dodger's mathematics in something more interesting than symbolic magic. To me, it's such an obvious lost opportunity. I'm still upset about this book. McGuire does a lovely bit of world-building with Asphodel Baker, what little we see of her. I found the hidden alchemical war against her work by L. Frank Baum delightful, and enjoyed every excerpt from the fictional Over the Woodward Wall scattered throughout Middlegame. But a problem with inventing a fictional book to excerpt in a real novel is that the reader may decide that the fictional book sounds a lot better than the book they're reading, and start wishing they could just read that book instead. That was certainly the case for me. I'm sad that Over the Woodward Wall doesn't exist, and am mostly infuriated by Middlegame. Dodger and Erin deserved to live in a better book. Should you want to read this anyway (and I do know people who liked it), serious content warning for self-harm. Rating: 4 out of 10

26 May 2020

Russell Coker: Cruises and Covid19

Problems With Cruises GQ has an insightful and detailed article about Covid19 and the Diamond Princess [1], I recommend reading it. FastCompany has a brief article about bookings for cruises in August [2]. There have been many negative comments about this online. The first thing to note is that the cancellation policies on those cruises are more lenient than usual and the prices are lower. So it s not unreasonable for someone to put down a deposit on a half price holiday in the hope that Covid19 goes away (as so many prominent people have been saying it will) in the knowledge that they will get it refunded if things don t work out. Of course if the cruise line goes bankrupt then no-one will get a refund, but I think people are expecting that won t happen. The GQ article highlights some serious problems with the way cruise ships operate. They have staff crammed in to small cabins and the working areas allow transmission of disease. These problems can be alleviated, they could allocate more space to staff quarters and have more capable air conditioning systems to put in more fresh air. During the life of a cruise ship significant changes are often made, replacing engines with newer more efficient models, changing the size of various rooms for entertainment, installing new waterslides, and many other changes are routinely made. Changing the staff only areas to have better ventilation and more separate space (maybe capsule-hotel style cabins with fresh air piped in) would not be a difficult change. It would take some money and some dry-dock time which would be a significant expense for cruise companies. Cruises Are Great People like social environments, they want to have situations where there are as many people as possible without it becoming impossible to move. Cruise ships are carefully designed for the flow of passengers. Both the layout of the ship and the schedule of events are carefully planned to avoid excessive crowds. In terms of meeting the requirement of having as many people as possible in a small area without being unable to move cruise ships are probably ideal. Because there is a large number of people in a restricted space there are economies of scale on a cruise ship that aren t available anywhere else. For example the main items on the menu are made in a production line process, this can only be done when you have hundreds of people sitting down to order at the same time. The same applies to all forms of entertainment on board, they plan the events based on statistical knowledge of what people want to attend. This makes it more economical to run than land based entertainment where people can decide to go elsewhere. On a ship a certain portion of the passengers will see whatever show is presented each night, regardless of whether it s singing, dancing, or magic. One major advantage of cruises is that they are all inclusive. If you are on a regular holiday would you pay to see a singing or dancing show? Probably not, but if it s included then you might as well do it and it will be pretty good. This benefit is really appreciated by people taking kids on holidays, if kids do things like refuse to attend a performance that you were going to see or reject food once it s served then it won t cost any extra. People Who Criticise Cruises For the people who sneer at cruises, do you like going to bars? Do you like going to restaurants? Live music shows? Visiting foreign beaches? A cruise gets you all that and more for a discount price. If Groupon had a deal that gave you a cheap hotel stay with all meals included, free non-alcoholic drinks at bars, day long entertainment for kids at the kids clubs, and two live performances every evening how many of the people who reject cruises would buy it? A typical cruise is just like a Groupon deal for non-stop entertainment from 8AM to 11PM. Will Cruises Restart? The entertainment options that cruises offer are greatly desired by many people. Most cruises are aimed at budget travellers, the price is cheaper than a hotel in a major city. Such cruises greatly depend on economies of scale, if they can t get the ships filled then they would need to raise prices (thus decreasing demand) to try to make a profit. I think that some older cruise ships will be scrapped in the near future and some of the newer ships will be sold to cruise lines that cater to cheap travel (IE P&O may scrap some ships and some of the older Princess ships may be transferred to them). Overall I predict a decrease in the number of middle-class cruise ships. For the expensive cruises (where the cheapest cabins cost over $1000US per person per night) I don t expect any real changes, maybe they will have fewer passengers and higher prices to allow more social distancing or something. I am certain that cruises will start again, but it s too early to predict when. Going on a cruise is about as safe as going to a concert or a major sporting event. No-one is predicting that sporting stadiums will be closed forever or live concerts will be cancelled forever, so really no-one should expect that cruises will be cancelled forever. Whether companies that own ships or stadiums go bankrupt in the mean time is yet to be determined. One thing that s been happening for years is themed cruises. A group can book out an entire ship or part of a ship for a themed cruise. I expect this to become much more popular when cruises start again as it will make it easier to fill ships. In the past it seems that cruise lines let companies book their ships for events but didn t take much of an active role in the process. I think that the management of cruise lines will look to aggressively market themed cruises to anyone who might help, for starters they could reach out to every 80s and 90s pop group those fans are all old enough to be interested in themed cruises and the musicians won t be asking for too much money. Conclusion Humans are social creatures. People want to attend events with many other people. Covid 19 won t be the last pandemic, and it may not even be eradicated in the near future. The possibility of having a society where no-one leaves home unless they are in a hazmat suit has been explored in science fiction, but I don t think that s a plausible scenario for the near future and I don t think that it s something that will be caused by Covid 19.

Christian Kastner: Curved Monitor

It's been two weeks since I purchased my first curved monitor. Switching away from a flat panel proved to be a novel and unusual experience so much, in fact, that within the first five minutes, I already wanted to return it. Nevertheless, I gave it a try, and I'm glad I did, because not only did I eventually get over the initially perceived issues, I'm now extremely satisfied with it.
Shifted Perspective My sole motivation for the switch was that I had become irritated (to a probably irrational degree) by reading and writing text in whatever window tile was on the left side of my desktop. Even though my previous monitor wasn't a particularly large one with 24", the shift in perspective on the far side of that window always made me feel as if I were reading something to the side of me, rather than in front of me even if I turned to face it directly. It was time to try out a curved monitor.
Process Purchasing something like a monitor is always a pain; there's just so much choice. I would have preferred something with an IPS panel, 4K resolution, and either a 27" or 32" size, and would compromise for a VA panel and WQHD resolution. On geizhals.at, an Austrian price comparison site, ~50 monitors satisfied those criteria. Further limiting the list to reputable brands and reasonable prices still left me with more than two dozen options. Without going into the details why (I was just glad to be done with it), I eventually settled for an MSI Optix MAG271CQR, a 27" WQHD monitor with a VA panel. Once the new monitor arrived, I removed the old monitor from my VESA desk mount, installed the new one, booted, and gave it a try. Within the first five minutes of use, I made three key observations:
  1. My shifted perspective issue on the sides was solved (great!), and
  2. I had gained quite a bit of screen real estate (great!), but
  3. Because of the curvature, the bottom task bar now looked bent (Oh Noes).
Now, point (3) might not sound like that big of an issue, but when you're willing to change your monitor just because vim looks kind of weird to you when it's window is on the left side of the desktop, then a bent-looking task bar is a deal-breaker. I decided that I had to return it. However, that meant: removing it, re-boxing it, shipping it back, etc. Tedious work. As it was already mounted and connected, a friend encouraged me to give it a day or two anyway, just in case. That turned out to be great advice. I would never have expected this, but I got over the bent-looking task bar issue pretty fast. The pleasure of a corrected perspective on either side (everything just looks "right" now) more than makes up for the bent-looking tar bar at the bottom; I don't even notice it anymore. And the added screen real estate is a bonus I hadn't planned for. The MAG271CQR targets the gaming demographic, and thus comes loaded with various features. My new favorite is "Reader Mode", which has an effect quite similar to "Night Mode" on mobile devices (reduced brightness, blue light filter). My eyes barely tire anymore, even after a long day's use. It also has a Picture-in-Picture mode for a second input which I haven't tried yet, but should come in handy for SBCs and the like.

Russ Allbery: Review: The Ten Thousand Doors of January

Review: The Ten Thousand Doors of January, by Alix E. Harrow
Publisher: Redhook
Copyright: September 2019
ISBN: 0-316-42198-7
Format: Kindle
Pages: 373
In 1901, at the age of seven, January found a Door. It was barely more than a frame in a ruined house in a field in Kentucky, but she wrote a story about opening it, and then did.
Once there was a brave and temeraryous (sp?) girl who found a Door. It was a magic Door that's why it has a capital D. She opened the Door.
The Door led to a bluff over the sea and above a city, a place very far from Kentucky, and she almost stayed, but she came back through the Door when her guardian, Mr. Locke, called. The adventure cost her a diary, several lectures, days of being locked in her room, and the remnants of her strained relationship with her father. When she went back, the frame of the Door was burned to the ground. That was the end of Doors for January for some time, and the continuation of a difficult childhood. She was cared for by her father's employer as a sort of exotic pet, dutifully attempting to obey, grateful for Mr. Locke's protection, and convinced that he was occasionally sneaking her presents through a box in the Pharaoh Room out of some hidden kindness. Her father appeared rarely, said little, and refused to take her with him. Three things helped: the grocery boy who smuggled her stories, an intimidating black woman sent by her father to replace her nurse, and her dog.
Once upon a time there was a good girl who met a bad dog, and they became the very best of friends. She and her dog were inseparable from that day forward.
I will give you a minor spoiler that I would have preferred to have had, since it would have saved me some unwarranted worry and some mental yelling at the author: The above story strains but holds. January's adventure truly starts the day before her seventeenth birthday, when she finds a book titled The Ten Thousand Doors in the box in the Pharaoh Room. As you may have guessed from the title, The Ten Thousand Doors of January is a portal fantasy, but it's the sort of portal fantasy that is more concerned with the portal itself than the world on the other side of it. (Hello to all of you out there who, like me, have vivid memories of the Wood between the Worlds.) It's a book about traveling and restlessness and the possibility of escape, about the ability to return home again, and about the sort of people who want to close those doors because the possibility of change created by people moving around freely threatens the world they have carefully constructed. Structurally, the central part of the book is told by interleaving chapters of January's tale with chapters from The Ten Thousand Doors. That book within a book starts with the framing of a scholarly treatment but quickly becomes a biography of a woman: Adelaide Lee Larson, a half-wild farm girl who met her true love at the threshold of a Door and then spent much of her life looking for him. I am not a very observant reader for plot details, particularly for books that I'm enjoying. I read books primarily for the emotional beats and the story structure, and often miss rather obvious story clues. (I'm hopeless at guessing the outcomes of mysteries.) Therefore, when I say that there are many things January is unaware of that are obvious to the reader, that's saying a lot. Even more clues were apparent when I skimmed the first chapter again, and a more observant reader would probably have seen them on the first read. Right down to Mr. Locke's name, Harrow is not very subtle about the moral shape of this world. That can make the early chapters of the book frustrating. January is being emotionally (and later physically) abused by the people who have power in her life, but she's very deeply trapped by false loyalty and lack of external context. Winning free of that is much of the story of the book, and at times it has the unpleasantness of watching someone make excuses for her abuser. At other times it has the unpleasantness of watching someone be abused. But this is the place where I thought the nested story structure worked marvelously. January escapes into the story of The Ten Thousand Doors at the worst moments of her life, and the reader escapes with her. Harrow uses the desire to switch scenes back to the more adventurous and positive story to construct and reinforce the emotional structure of the book. For me, it worked extremely well. It helps that the ending is glorious. The payoff is worth all the discomfort and tension-building in the first half of the book. Both The Ten Thousand Doors and the surrounding narrative reach deeply satisfying conclusions, ones that are entangled but separate in just the ways that they need to be. January's abilities, actions, and decisions at the end of the book were just the outcome that I needed but didn't entirely guess in advance. I could barely put down the last quarter of this story and loved every moment of the conclusion. This is the sort of book that can be hard to describe in a review because its merits don't rest on an original twist or easily-summarized idea. The elements here are all elements found in other books: portal fantasy, the importance of story-telling, coming of age, found family, irrepressible and indomitable characters, and the battle of the primal freedom of travel and discovery and belief against the structural forces that keep rulers in place. The merits of this book are in the small details: the way that January's stories are sparse and rare and sometimes breathtaking, the handling of tattoos, the construction of other worlds with a few deft strokes, and the way Harrow embraces the emotional divergence between January's life and Adelaide's to help the reader synchronize the emotional structure of their reading experience with January's.
She writes a door of blood and silver. The door opens just for her.
The Ten Thousand Doors of January is up against a very strong slate for both the Nebula and the Hugo this year, and I suspect it may be edged out by other books, although I wouldn't be unhappy if it won. (It probably has a better shot at the Nebula than the Hugo.) But I will be stunned if Harrow doesn't walk away with the Mythopoeic Award. This seems like exactly the type of book that award was created for. This is an excellent book, one of the best I've read so far this year. Highly recommended. Rating: 9 out of 10

25 May 2020

Russ Allbery: Review: The Last Emperox

Review: The Last Emperox, by John Scalzi
Series: Interdependency #3
Publisher: Tor
Copyright: April 2020
ISBN: 0-7653-8917-7
Format: Kindle
Pages: 318
This is the conclusion of the Interdependency trilogy, which is a single story told in three books. Start with The Collapsing Empire. You don't want to read this series out of order. All the pieces and players are in place, the causes and timeline of the collapse of the empire she is accidentally ruling are now clear, and Cardenia Wu-Patrick knows who her friends and enemies are. What she doesn't know is what she can do about it. Her enemies, unfettered Cardenia's ethics or desire to save the general population, have the advantage of clearer and more achievable goals. If they survive and, almost as important, remain in power, who cares what happens to everyone else? As with The Consuming Fire, the politics may feel a bit too on-the-nose for current events, this time for the way that some powerful people are handling (or not handling) the current pandemic. Also as with The Consuming Fire, Scalzi's fast-moving story, likable characters, banter, and occasional humorous descriptions prevent those similarities from feeling heavy or didactic. This is political wish fulfillment to be sure, but it doesn't try to justify itself or linger too much on its improbabilities. It's a good story about entertaining people trying (mostly) to save the world with a combination of science and political maneuvering. I picked up The Last Emperox as a palate cleanser after reading Gideon the Ninth, and it provided exactly what I was looking for. That gave me an opportunity to think about what Scalzi does in his writing, why his latest novel was one of my first thoughts for a palate cleanser, and why I react to his writing the way that I do. Scalzi isn't a writer about whom I have strong opinions. In my review of The Collapsing Empire, I compared his writing to the famous description of Asimov as the "default voice" of science fiction, but that's not quite right. He has a distinct and easily-recognizable style, heavy on banter and light-hearted description. But for me his novels are pleasant, reliable entertainment that I forget shortly after reading them. They don't linger or stand out, even though I enjoy them while I'm reading them. That's my reaction. Others clearly do not have that reaction, fully engage with his books, and remember them vividly. That indicates to me that there's something his writing is doing that leaves substantial room for difference of personal taste and personal reaction to the story, and the sharp contrast between The Last Emperox and Gideon the Ninth helped me put my finger on part of it. I don't feel like Scalzi's books try to tell me how to feel about the story. There's a moment in The Last Emperox where Cardenia breaks down crying over an incredibly difficult decision that she's made, one that the readers don't find out about until later. In another book, there would be considerably more emotional build-up to that moment, or at least some deep analysis of it later once the decision is revealed. In this book, it's only a handful of paragraphs and then a few pages of processing later, primarily in dialogue, and less focused on the emotions of the characters than on the forward-looking decisions they've made to deal with those emotions. The emotion itself is subtext. Many other authors would try to pull the reader into those moments and make them feel what the characters are feeling. Scalzi just relates them, and leaves the reader free to feel what they choose to feel. I don't think this is a flaw (or a merit) in Scalzi's writing; it's just a difference, and exactly the difference that made me reach for this book as an emotional break after a book that got its emotions all over the place. Calling Scalzi's writing emotionally relaxing isn't quite right, but it gives me space to choose to be emotionally relaxed if I want to be. I can pick the level of my engagement. If I want to care about these characters and agonize over their decisions, there's enough information here to mull over and use to recreate their emotional states. If I just want to read a story about some interesting people and not care too much about their hopes and dreams, I can choose to do that instead, and the book won't fight me. That approach lets me sidle up on the things that I care about and think about them at my leisure, or leave them be. This approach makes Scalzi's books less intense than other novels for me. This is where personal preference comes in. I read books in large part to engage emotionally with the characters, and I therefore appreciate books that do a lot of that work for me. Scalzi makes me do the work myself, and the result is not as effective for me, or as memorable. I think this may be part of what I and others are picking up on when we say that Scalzi's writing is reminiscent of classic SF from decades earlier. It used to be common for SF to not show any emotional vulnerability in the main characters, and to instead focus on the action plot and the heroics and martial virtues. This is not what Scalzi is doing, to be clear; he has a much better grasp of character and dialogue than most classic SF, adds considerable light-hearted humor, and leaves clear clues and hooks for a wide range of human emotions in the story. But one can read Scalzi in that tone if one wants to, since the emotional hooks do not grab hard at the reader and dig in. By comparison, you cannot read Gideon the Ninth without grappling with the emotions of the characters. The book will not let you. I think this is part of why Scalzi is so consistent for me. If you do not care deeply about Gideon Nav, you will not get along with Gideon the Ninth, and not everyone will. But several main characters in The Last Emperox (Mance and to some extent Cardenia) did little or nothing for me emotionally, and it didn't matter. I liked Kiva and enjoyed watching her strategically smash her way through social conventions, but it was easy to watch her from a distance and not get too engrossed in her life or her thoughts. The plot trundled along satisfyingly, regardless. That lack of emotional involvement precludes, for me, a book becoming the sort of work that I will rave about and try to press into other people's hands, but it also makes it comfortable and gentle and relaxing in a way that a more emotionally fraught book could not be. This is a long-winded way to say that this was a satisfying conclusion to a space opera trilogy that I enjoyed reading, will recommend mildly to others, and am already forgetting the details of. If you liked the first two books, this is an appropriate and fun conclusion with a few new twists and a satisfying amount of swearing (mostly, although not entirely, from Kiva). There are a few neat (albeit not horribly original) bits of world-building, a nice nod to and subversion of Asimov, a fair bit of political competency wish fulfillment (which I didn't find particularly believable but also didn't mind being unbelievable), and one enjoyable "oh no she didn't" moment. If you like the thing that Scalzi is doing, you will enjoy this book. Rating: 8 out of 10

24 May 2020

Enrico Zini: Music links

It's the end of the world as we know it, twice as fast
After Homemade Instruments Week on the facebook page, here is an article with some PVC pipes instruments! Percussion on PVC pipes A classic, long pipes for big bass, easy to tune by changing the length
"Ut queant laxis" or "Hymnus in Ioannem" is a Latin hymn in honor of John the Baptist, written in Horatian Sapphics and traditionally attributed to Paulus Diaconus, the eighth-century Lombard historian. It is famous for its part in the history of musical notation, in particular solmization. The hymn belongs to the tradition of Gregorian chant.

23 May 2020

Raphaël Hertzog: Freexian s report about Debian Long Term Support, April 2020

A Debian LTS logo Like each month, here comes a report about the work of paid contributors to Debian LTS. Individual reports In April, 284.5 work hours have been dispatched among 14 paid contributors. Their reports are available: Evolution of the situation In April we dispatched more hours than ever and another was new too, we had our first (virtual) contributors meeting on IRC! Logs and minutes are available and we plan to continue doing IRC meetings every other month.
Sadly one contributor decided to go inactive in April, Hugo Lefeuvre.
Finally, we like to remind you, that the end of Jessie LTS is coming in less than two months!
In case you missed it (or missed to act), please read this post about keeping Debian 8 Jessie alive for longer than 5 years. If you expect to have Debian 8 servers/devices running after June 30th 2020, and would like to have security updates for them, please get in touch with Freexian. The security tracker currently lists 4 packages with a known CVE and the dla-needed.txt file has 25 packages needing an update. Thanks to our sponsors New sponsors are in bold.

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Reproducible Builds (diffoscope): diffoscope 145 released

The diffoscope maintainers are pleased to announce the release of diffoscope version 145. This version includes the following changes:
[ Chris Lamb ]
* Improvements:
  - Add support for Apple Xcode mobile provisioning .mobilepovision files.
    (Closes: reproducible-builds/diffoscope#113)
  - Add support for printing the signatures via apksigner(1).
    (Closes: reproducible-builds/diffoscope#121)
  - Use SHA256 over MD5 when generating page names for the HTML directory
    presenter, validate checksums for files referenced in .changes files
    using SHA256 too, and move to using SHA256 in "Too much input for diff"
    output too. (Closes: reproducible-builds/diffoscope#124)
  - Don't leak the full path of the temporary directory in "Command [..]
    exited with 1".  (Closes: reproducible-builds/diffoscope#126)
  - Identify "iOS App Zip archive data" files as .zip files.
    (Closes: reproducible-builds/diffoscope#116)
* Bug fixes:
  - Correct "differences" typo in the ApkFile handler.
    (Closes: reproducible-builds/diffoscope#127)
* Reporting/output improvements:
  - Never emit the same id="foo" TML anchor reference twice, otherwise
    identically-named parts will not be able to linked to via "#foo".
    (Closes: reproducible-builds/diffoscope#120)
  - Never emit HTML with empty "id" anchor lements as it is not possible to
    link to "#" (vs "#foo"). We use "#top" as a fallback value so it will
    work for the top-level parent container.
  - Clarify the message when we cannot find the "debian" Python module.
  - Clarify "Command [..] failed with exit code" to remove duplicate "exited
    with exit" but also to note that diffoscope is interpreting this as an
    error.
  - Add descriptions for the 'fallback' Debian module file types.
  - Rename the --debugger command-line argument to --pdb.
* Testsuite improvements:
  - Prevent CI (and runtime) apksigner test failures due to lack of
    binfmt_misc on Salsa CI and elsewhere.
* Codebase improvements:
  - Initially add a pair of comments to tidy up a slightly abstraction level
    violating code in diffoscope.comparators.mising_file and the
    .dsc/.buildinfo file handling, but replace this later by by inlining
    MissingFile's special handling of deb822 to prevent leaking through
    abstraction layers in the first place.
  - Use a BuildinfoFile (etc.) regardless of whether the associated files
    such as the orig.tar.gz and the .deb are present, but don't treat them as
    actual containers. (Re: reproducible-builds/diffoscope#122)
  - Rename the "Openssl" command class to "OpenSSLPKCS7" to accommodate other
    commands with this prefix.
  - Wrap a docstring across multiple lines, drop an inline pprint import and
    comment the HTMLPrintContext class, etc.
[ Emanuel Bronshtein ]
* Avoid build-cache in building the released Docker image.
  (Closes: reproducible-builds/diffoscope#123)
[ Holger Levsen ]
* Wrap long lines in older changelog entries.
You find out more by visiting the project homepage.

22 May 2020

Bits from Debian: Debian welcomes the 2020 GSOC interns

GSoC logo We are very excited to announce that Debian has selected nine interns to work under mentorship on a variety of projects with us during the Google Summer of Code. Here are the list of the projects, students, and details of the tasks to be performed.
Project: Android SDK Tools in Debian Deliverables of the project: Make the entire Android toolchain, Android Target Platform Framework, and SDK tools available in the Debian archives.
Project: Packaging and Quality assurance of COVID-19 relevant applications Deliverables of the project: Quality assurance including bug fixing, continuous integration tests and documentation for all Debian Med applications that are known to be helpful to fight COVID-19
Project: BLAS/LAPACK Ecosystem Enhancement Deliverables of the project: Better environment, documentation, policy, and lintian checks for BLAS/LAPACK.
Project: Quality Assurance and Continuous integration for applications in life sciences and medicine Deliverables of the project: Continuous integration tests for all Debian Med applications, QA review, and bug fixes.
Project: Systemd unit translator Deliverables of the project: A systemd unit to OpenRC init script translator. Updated OpenRC package into Debian Unstable.
Project: Architecture Cross-Grading Support in Debian Deliverables of the project: Evaluate, test, and develop tools to evaluate cross-grade checks for system and user configuration.
Project: Upstream/Downstream cooperation in Ruby Deliverables of the project: Create guide for rubygems.org on good practices for upstream maintainers, develop a tool that can detect problems and, if possible fix those errors automatically. Establish good documentation, design the tool to be extensible for other languages.
Congratulations and welcome to all the interns! The Google Summer of Code program is possible in Debian thanks to the efforts of Debian Developers and Debian Contributors that dedicate part of their free time to mentor interns and outreach tasks. Join us and help extend Debian! You can follow the interns' weekly reports on the debian-outreach mailing-list, chat with us on our IRC channel or reach out to the individual projects' team mailing lists.

17 May 2020

Enrico Zini: Art links

Guglielmo Achille Cavellini (11 September 1914 20 November 1990), also known as GAC, was an Italian artist and art collector. After an initial activity as a painter, in the 1940s and 1950s he became one of the major collectors of contemporary Italian abstract art, developing a deep relationship of patronage and friendship with the artists. This experience has its pinnacle in the exhibition Modern painters of the Cavellini collection at the National Gallery of Modern Art in Rome in 1957. In the 1960s Cavellini resumed his activity as an artist, with an ample production spanning from Neo-Dada to performance art to mail art, of which he became one of the prime exponents with the Exhibitions at Home and the Round Trip works. In 1971 he invented autostoricizzazione (self-historicization), upon which he acted to create a deliberate popular history surrounding his existence. He also authored the books Abstract Art (1959), Man painter (1960), Diary of Guglielmo Achille Cavellini (1975), Encounters/Clashes in the Jungle of Art (1977) and Life of a Genius (1989).
Paul Gustave Louis Christophe Dor (/d re /; French: [ ys.tav d . e]; 6 January 1832 23 January 1883[1]) was a French artist, printmaker, illustrator, comics artist, caricaturist, and sculptor who worked primarily with wood-engraving.
Enrico Baj era bravissimo a pij per culo er potere usanno a fantasia. Co quaa sempricit che solo dii granni, raccatta robbe tipo bottoni, pezzi de stoffa, cordoni, passamanerie varie, e l appiccica su a tela insieme aa pittura sua: che pare quasi che sta a gioc ma giocanno giocanno, zitto zitto, riesce a rovesci er monno. >>

Russ Allbery: krb5-strength 3.2

krb5-strength provides password strength checking for Kerberos KDCs (either MIT or Heimdal), and also provides a password history implementation for Heimdal. This release adds a check-only mode to the heimdal-history command to interrogate history without modifying it and increases the default hash iterations used when storing old passwords. explicit_bzero is now used, where available, to clear the memory used for passwords after processing. krb5-strength can now optionally be built without CrackLib support at all, if you only want to use the word list, edit distance, or length and character class rules. It's been a few years since the previous release, so this release also updates all the portability code, overhauls valgrind testing, and now passes tests when built with system CrackLib (by skipping tests for passwords that are rejected by the stronger rules of the embedded CrackLib fork). You can get the latest release from the krb5-strength distribution page. New packages will be uploaded to Debian unstable shortly (as soon as a Perl transition completes enough to make the package buildable in unstable).

Dirk Eddelbuettel: RcppArmadillo 0.9.880.1.0

armadillo image Armadillo is a powerful and expressive C++ template library for linear algebra aiming towards a good balance between speed and ease of use with a syntax deliberately close to a Matlab. RcppArmadillo integrates this library with the R environment and language and is widely used by (currently) 719 other packages on CRAN. Conrad released a new upstream version 9.880.1 of Armadillo on Friday which I packaged and tested as usual (result log here in the usual repo). The R package also sports a new OpenMP detection facility once again motivated by macOS which changed its setup yet again. Changes in the new release are noted below.

Changes in RcppArmadillo version 0.9.880.1.0 (2020-05-15)
  • Upgraded to Armadillo release 9.880.1 (Roasted Mocha Detox)
    • expanded qr() to optionally use pivoted decomposition
    • updated physical constants to NIST 2018 CODATA values
    • added ARMA_DONT_USE_CXX11_MUTEX confguration option to disable use of std::mutex
  • OpenMP capability is tested explicitly (Kevin Ushey and Dirk in #294, #295, and #296 all fixing #290).

Courtesy of 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 R-Forge page. If you like this or other open-source work I do, you can now sponsor me at GitHub. For the first year, GitHub will match your contributions.

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

Erich Schubert: Contact Tracing Apps are Useless

Some people believe that automatic contact tracing apps will help contain the Coronavirus epidemic. They won t. Sorry to bring the bad news, but IT and mobile phones and artificial intelligence will not solve every problem. In my opinion, those that promise to solve these things with artificial intelligence / mobile phones / apps / your-favorite-buzzword are at least overly optimistic and blinder Aktionismus (*), if not naive, detachted from reality, or fraudsters that just want to get some funding. (*) there does not seem to be an English word for this doing something just for the sake of doing something, without thinking about whether it makes sense to do so Here are the reasons why it will not work:
  1. Signal quality. Forget detecting proximity with Bluetooth Low Energy. Yes, there are attempts to use BLE beacons for indoor positioning. But these use that you can learn fingerprints of which beacons are visible at which points, combined with additional information such as movement sensors and history (you do not teleport around in a building). BLE signals and antennas apparently tend to be very prone to orientation differences, signal reflections, and of course you will not have the idealized controlled environment used in such prototypes. The contacts have a single device, and they move this is not comparable to indoor positioning. I strongly doubt you can tell whether you are close to someone, or not.
  2. Close vs. protection. The app cannot detect protection in place. Being close to someone behind a plexiglass window or even a solid wall is very different from being close otherwise. You will get a lot of false contacts this way. That neighbor that you have never seen living in the appartment above will likely be considered a close contact of yours, as you sleep next to each other every day
  3. Low adoption rates. Apparently even in technology affine Singapore, fewer than 20% of people installed the app. That does not even mean they use it regularly. In Austria, the number is apparently below 5%, and people complain that it does not detect contact But in order for this approach to work, you will need Chinese-style mass surveillance that literally puts you in prison if you do not install the app.
  4. False alerts. Because of these issues, you will get false alerts, until you just do not care anymore.
  5. False sense of security. Honestly: the app does not pretect you at all. All it tries to do is to make the tracing of contacts easier. It will not tell you reliably if you have been infected (as mentioned above, too many false positives, too few users) nor that you are relatively safe (too few contacts included, too slow testing and reporting). It will all be on the quality of about 10 days ago you may or may not have contact with someone that tested positive, please contact someone to expose more data to tell you that it is actually another false alert .
  6. Trust. In Germany, the app will be operated by T-Systems and SAP. Not exactly two companies that have a lot of fans SAP seems to be one of the most hated software around. Neither company is known for caring about privacy much, but they are prototypical for business first . Its trust the cat to keep the cream. Yes, I know they want to make it open-source. But likely only the client, and you will still have to trust that the binary in the app stores is actually built from this source code, and not from a modified copy. As long as the name T-Systems and SAP are associated to the app, people will not trust it. Plus, we all know that the app will be bad, given the reputation of these companies at making horrible software systems
  7. Too late. SAP and T-Systems want to have the app ready in mid June. Seriously, this must be a joke? It will be very buggy in the beginning (because it is SAP!) and it will not be working reliably before end of July. There will not be a substantial user before fall. But given the low infection rates in Germany, nobody will bother to install it anymore, because the perceived benefit is 0 one the infection rates are low.
  8. Infighting. You may remember that there was the discussion before that there should be a pan-european effort. Except that in the end, everybody fought everybody else, countries went into different directions and they all broke up. France wanted a centralized systems, while in Germany people pointed out that the users will not accept this and only a distributed system will have a chance. That failed effort was known as Pan-European Privacy-Preserving Proximity Tracing (PEPP-PT) vs. Decentralized Privacy-Preserving Proximity Tracing (DP-3T) , and it turned out to have become a big clusterfuck . And that is just the tip of the iceberg.
Iceleand, probably the country that handled the Corona crisis best (they issued a travel advisory against Austria, when they were still happily spreading the virus at apres-ski; they massively tested, and got the infections down to almost zero within 6 weeks), has been experimenting with such an app. Iceland as a fairly close community managed to have almost 40% of people install their app. So did it help? No: The technology is more or less I wouldn t say useless [ ] it wasn t a game changer for us. The contact tracing app is just a huge waste of effort and public money. And pretty much the same applies to any other attempts to solve this with IT. There is a lot of buzz about solving the Corona crisis with artificial intelligence: bullshit! That is just naive. Do not speculate about magic power of AI. Get the data, understand the data, and you will see it does not help. Because its real data. Its dirty. Its late. Its contradicting. Its incomplete. It is all what AI currently can not handle well. This is not image recognition. You have no labels. Many of the attempts in this direction already fail at the trivial 7-day seasonality you observe in the data For example, the widely known John Hopkins Has the curve flattened trend has a stupid, useless indicator based on 5 day averages. And hence you get the weekly up and downs due to weekends. They show pretty up and down indicators. But these are affected mostly by the day of the week. And nobody cares. Notice that they currently even have big negative infections in their plots? There is no data on when someone was infected. Because such data simply does not exist. What you have is data when someone tested positive (mostly), when someone reported symptons (sometimes, but some never have symptoms!), and when someone dies (but then you do not know if it was because of Corona, because of other issues that became just worse because of Corona, or hit by a car without any relation to Corona). The data that we work with is incredibly delayed, yet we pretend it is live . Stop reading tea leaves. Stop pretending AI can save the world from Corona.

Matthew Palmer: Private Key Redaction: UR DOIN IT RONG

Because posting private keys on the Internet is a bad idea, some people like to redact their private keys, so that it looks kinda-sorta like a private key, but it isn t actually giving away anything secret. Unfortunately, due to the way that private keys are represented, it is easy to redact a key in such a way that it doesn t actually redact anything at all. RSA private keys are particularly bad at this, but the problem can (potentially) apply to other keys as well. I ll show you a bit of Inside Baseball with key formats, and then demonstrate the practical implications. Finally, we ll go through a practical worked example from an actual not-really-redacted key I recently stumbled across in my travels.

The Private Lives of Private Keys Here is what a typical private key looks like, when you come across it:
-----BEGIN RSA PRIVATE KEY-----
MGICAQACEQCxjdTmecltJEz2PLMpS4BXAgMBAAECEDKtuwD17gpagnASq1zQTYEC
CQDVTYVsjjF7IQIJANUYZsIjRsR3AgkAkahDUXL0RSECCB78r2SnsJC9AghaOK3F
sKoELg==
-----END RSA PRIVATE KEY-----
Obviously, there s some hidden meaning in there computers don t encrypt things by shouting BEGIN RSA PRIVATE KEY! , after all. What is between the BEGIN/END lines above is, in fact, a base64-encoded DER format ASN.1 structure representing a PKCS#1 private key. In simple terms, it s a list of numbers very important numbers. The list of numbers is, in order:
  • A version number (0);
  • The public modulus , commonly referred to as n ;
  • The public exponent , or e (which is almost always 65,537, for various unimportant reasons);
  • The private exponent , or d ;
  • The two private primes , or p and q ;
  • Two exponents, which are known as dmp1 and dmq1 ; and
  • A coefficient, known as iqmp .

Why Is This a Problem? The thing is, only three of those numbers are actually required in a private key. The rest, whilst useful to allow the RSA encryption and decryption to be more efficient, aren t necessary. The three absolutely required values are e, p, and q. Of the other numbers, most of them are at least about the same size as each of p and q. So of the total data in an RSA key, less than a quarter of the data is required. Let me show you with the above toy key, by breaking it down piece by piece1:
  • MGI DER for this is a sequence
  • CAQ version (0)
  • CxjdTmecltJEz2PLMpS4BX n
  • AgMBAA e
  • ECEDKtuwD17gpagnASq1zQTY d
  • ECCQDVTYVsjjF7IQ p
  • IJANUYZsIjRsR3 q
  • AgkAkahDUXL0RS dmp1
  • ECCB78r2SnsJC9 dmq1
  • AghaOK3FsKoELg== iqmp
Remember that in order to reconstruct all of these values, all I need are e, p, and q and e is pretty much always 65,537. So I could redact almost all of this key, and still give all the important, private bits of this key. Let me show you:
-----BEGIN RSA PRIVATE KEY-----
..............................................................EC
CQDVTYVsjjF7IQIJANUYZsIjRsR3....................................
........
-----END RSA PRIVATE KEY-----
Now, I doubt that anyone is going to redact a key precisely like this but then again, this isn t a typical RSA key. They usually look a lot more like this:
-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----
People typically redact keys by deleting whole lines, and usually replacing them with [...] and the like. But only about 345 of those 1588 characters (excluding the header and footer) are required to construct the entire key. You can redact about 4/5ths of that giant blob of stuff, and your private parts (or at least, those of your key) are still left uncomfortably exposed.

But Wait! There s More! Remember how I said that everything in the key other than e, p, and q could be derived from those three numbers? Let s talk about one of those numbers: n. This is known as the public modulus (because, along with e, it is also present in the public key). It is very easy to calculate: n = p * q. It is also very early in the key (the second number, in fact). Since n = p * q, it follows that q = n / p. Thus, as long as the key is intact up to p, you can derive q by simple division.

Real World Redaction At this point, I d like to introduce an acquaintance of mine: Mr. Johan Finn. He is the proud owner of the GitHub repo johanfinn/scripts. For a while, his repo contained a script that contained a poorly-redacted private key. He since deleted it, by making a new commit, but of course because git never really deletes anything, it s still available. Of course, Mr. Finn may delete the repo, or force-push a new history without that commit, so here is the redacted private key, with a bit of the surrounding shell script, for our illustrative pleasure:
#Add private key to .ssh folder
cd /home/johan/.ssh/
echo  "-----BEGIN RSA PRIVATE KEY-----
MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
KKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKKK
 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:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::.::
:::::::::::::::::::::::::::.::::::::::::::::::::::::::::::::::::
LLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLlL
 
 
 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-----END RSA PRIVATE KEY-----" >> id_rsa
Now, if you try to reconstruct this key by removing the obvious garbage lines (the ones that are all repeated characters, some of which aren t even valid base64 characters), it still isn t a key at least, openssl pkey doesn t want anything to do with it. The key is very much still in there, though, as we shall soon see. Using a gem I wrote and a quick bit of Ruby, we can extract a complete private key. The irb session looks something like this:
>> require "derparse"
>> b64 = <<EOF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>> b64 += <<EOF
gff0GJCOMZ65pMSy3A3cSAtjlKnb4fWzuHD5CFbusN4WhCT/tNxGNSpzvxd8GIDs
nY7exs9L230oCCpedVgcbayHCbkChEfoPzL1e1jXjgCwCTgt8GjeEFqc1gXNEaUn
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KbdmBEfTR4e11Pn9vYdu9/i6o10U4hpmf4TYKlqk10g1Sj21l8JATj/7Diey8scO
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AvMzXk5OXrUEALUvt84u6m6XZZ0pq5XZxq74s8p/x1JvTwcpJ3jDKNEixlHfdHEZ
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Y5mBAQKCAQEAzU7AnorPzYndlOzkxRFtp6MGsvRBsvvqPLCyUFEXrHNV872O7tdO
GmsMZl+q+TJXw7O54FjJJvqSSS1sk68AGRirHop7VQce8U36BmI2ZX6j2SVAgIkI
9m3btCCt5rfiCatn2+Qg6HECmrCsHw6H0RbwaXS4RZUXD/k4X+sslBitOb7K+Y+N
Bacq6QxxjlIqQdKKPs4P2PNHEAey+kEJJGEQ7bTkNxCZ21kgi1Sc5L8U/IGy0BMC
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Q0NCedq1JNatP1gsb6bcnVHFDEGsj/35oQKCAQEAgmWMuSrojR/fjJzvke6Wvbox
FRnPk+6YRzuYhAP/YPxSRYyB5at++5Q1qr7QWn7NFozFIVFFT8CBU36ktWQ39MGm
cJ5SGyN9nAbbuWA6e+/u059R7QL+6f64xHRAGyLT3gOb1G0N6h7VqFT25q5Tq0rc
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EDqe4RRJ3VKuKfZxHn5VLxgtBFN96Gy0+Htm5tiMKOZMYAkHiL+vrVZAX0hIEuRZ
EOF
>> der = b64.unpack("m").first
>> c = DerParse.new(der).first_node.first_child
>> version = c.value
=> 0
>> c = c.next_node
>> n = c.value
=> 80071596234464993385068908004931... # (etc)
>> c = c.next_node
>> e = c.value
=> 65537
>> c = c.next_node
>> d = c.value
=> 58438813486895877116761996105770... # (etc)
>> c = c.next_node
>> p = c.value
=> 29635449580247160226960937109864... # (etc)
>> c = c.next_node
>> q = c.value
=> 27018856595256414771163410576410... # (etc)
What I ve done, in case you don t speak Ruby, is take the two chunks of plausible-looking base64 data, chuck them together into a variable named b64, unbase64 it into a variable named der, pass that into a new DerParse instance, and then walk the DER value tree until I got all the values I need. Interestingly, the q value actually traverses the split in the two chunks, which means that there s always the possibility that there are lines missing from the key. However, since p and q are supposed to be prime, we can sanity check them to see if corruption is likely to have occurred:
>> require "openssl"
>> OpenSSL::BN.new(p).prime?
=> true
>> OpenSSL::BN.new(q).prime?
=> true
Excellent! The chances of a corrupted file producing valid-but-incorrect prime numbers isn t huge, so we can be fairly confident that we ve got the real p and q. Now, with the help of another one of my creations we can use e, p, and q to create a fully-operational battle key:
>> require "openssl/pkey/rsa"
>> k = OpenSSL::PKey::RSA.from_factors(p, q, e)
=> #<OpenSSL::PKey::RSA:0x0000559d5903cd38>
>> k.valid?
=> true
>> k.verify(OpenSSL::Digest::SHA256.new, k.sign(OpenSSL::Digest::SHA256.new, "bob"), "bob")
=> true
and there you have it. One fairly redacted-looking private key brought back to life by maths and far too much free time. Sorry Mr. Finn, I hope you re not still using that key on anything Internet-facing.

What About Other Key Types? EC keys are very different beasts, but they have much the same problems as RSA keys. A typical EC key contains both private and public data, and the public portion is twice the size so only about 1/3 of the data in the key is private material. It is quite plausible that you can redact an EC key and leave all the actually private bits exposed.

What Do We Do About It? In short: don t ever try and redact real private keys. For documentation purposes, just put KEY GOES HERE in the appropriate spot, or something like that. Store your secrets somewhere that isn t a public (or even private!) git repo. Generating a dummy private key and sticking it in there isn t a great idea, for different reasons: people have this odd habit of reusing demo keys in real life. There s no need to encourage that sort of thing.
  1. Technically the pieces aren t 100% aligned with the underlying DER, because of how base64 works. I felt it was easier to understand if I stuck to chopping up the base64, rather than decoding into DER and then chopping up the DER.

16 May 2020

Russ Allbery: C TAP Harness 4.7

This is a small bug fix release to my testing framework for C packages. It picks up a change to the test suite so that it won't break when C_TAP_VERBOSE is already set in the environment, and fixes new compilation warnings with GCC 10. You can get the latest release from the C TAP Harness distribution page.

Norbert Preining: Upgrading AMD Radeon 5700 to 5700 XT via BIOS

Having recently switched from NVIDIA to AMD graphic cards, in particular a RX 5700, I found out that I can get myself a free upgrade to the RX 5700 XT variant without paying one Yen, by simply flashing a compatible 5700 XT BIOS onto the 5700 card. Not that this is something new, a detailed explanation can be found here.
The same article also gives a detailed technical explanation on the difference between the two cards. The 5700 variant has less stream processors (2304 against 2560 in the XT variant), and lower power limits and clock speeds. Other than this they are based on the exact same chip layout (Navi 10), and with the same amount and type of memory 8 GB GDDR6. Flashing the XT BIOS onto the plain 5700 will not changes the number of stream processors, but power limits and clock speeds are raised to the same level of the 5700 XT, providing approximately a 7% gain without any over-clocking and over-powering, and potentially more by raising voltage etc. Detailed numbers can be found in the linked article above. The first step in this free upgrade is to identify ones own card correctly, best with device id and subsystem id, and then find the correct BIOS. Lots of BIOS dumps are provided in the BIOS database (link already restricting to 5700 XT BIOS). I used CPU-Z (Windows program) to determine this items, see image on the right (click to enlarge). In my case I got 1002 731F - 1462 3811 for the complete device id. The card is a MSI RX 5700 8 GB Mech OC, so I found the following alternative BIOS for MSI RX 5700 XT 8 GB Mech OC. Unfortunately, it seems that MSI is distinguishing 5700 and 5700 XT by their device id, because the XT variant gives 1002 731F - 1462 3810 for the complete device id, meaning that the last digit is 1 off compared to mine (3811 versus 3810). And indeed, trying to flash this video BIOS the normal way (using the Windows version ended in a warning that the subsystem id is different. A bit of search led to a thread in the TechPowerup Fora and this post explaining how to force the flashing in this case. Disclaimer: The following might brick your graphic card, you are doing this on your own risk! Necessary software: I did all the flashing and checking under Windows, but only because I realized too late that there is a fully uptodate flashing program for Linux that exhibits the same functionality. Also, I didn t know how to get the device id since the current AMD ROCm tools seem not to provide this data. If you are lucky and the device ids for your card are the same for both 5700 and 5700 XT variants, then you can use the graphical client (amdvbflashWin.exe), but if there is a difference, the command line is necessary. After unpacking the AMD Flash program and getting the correct BIOS rom file, the steps taken on Windows are (the very same steps can be taken on Linux): This should succeed in both cases. After that shutdown and restart your computer and you should be greeted with a RT 5700 XT card, without twisting a single screw. Starting Windows for the first time gave some flickering, because the driver for the new card was installed. On Linux the system auto-detects the card and everything works out of the box. Very smooth. Finally, a word of warning: Don t do these kind of things if you are not ready to pay the prize of a bricked GPU card in case something goes wrong! Everything is on your own risk! Let me close with a before/after image, most of the fields are identical, but the default/gpu clocks both at normal as well as boost levels see a considerable improvement

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