Once the private key of some HTTPS web site is compromised, an attacker is able to build a man-in-the-middle attack to intercept and decrypt any communication with the web site. The first step against such an attack is the revocation of the associated certificate through a CRL or a protocol like OCSP. Unfortunately, the attacker could also have recorded past communications protected by this private key and therefore decrypt them. Forward secrecy allows today information to be kept secret even if the private key is compromised in the future. Achieving this property is usually costly and therefore, most web servers do not enable it on purpose. Google recently announced support of forward secrecy on their HTTPS sites. Adam Langley wrote a post with more details on what was achieved to increase efficiency of such a mechanism: with a few fellow people, he wrote an efficient implementation of some elliptic curve cryptography for OpenSSL.

Without forward secrecy To understand the problem when forward secrecy is absent, let s look at the classic TLS handshake when using a cipher suite like AES128-SHA. During this handshake, the server will present its certificate and both the client and the server will agree on a master secret. This secret is built from a 48byte premaster secret generated and encrypted by the client with the public key of the server. It is then sent in a Client Key Exchange message to the server during the third step of the TLS handshake. The master secret is derived from this premaster secret and random values sent in clear-text with Client Hello and Server Hello messages. This scheme is secure as long as only the server is able to decrypt the premaster secret (with its private key) sent by the client. Let s suppose that an attacker records all exchanges between the server and clients during a year. Two years later, the server is decommissioned and sent for recycling. The attacker is able to recover the hard drive with the private key. She can now decrypt any session she recorded: the encrypted premaster secret sent by a client is decrypted with the private key and the master secret is derived from it. The attacker can now recover passwords and other sensitive information that can still be valuable today. The main problem lies in the fact that the private key is used for two purposes: authentication of the server and encryption of a shared secret. Authentication only matters while the communication is established, but encryption is expected to last for years.

Diffie-Hellman with discrete logarithm One way to solve the problem is to keep using the private key for authentication but uses an independent mechanism to agree on a shared secret. Hopefully, there exists a well-known protocol for this: the Diffie-Hellman key exchange. It is a method of exchanging keys without any prior knowledge. Here is how it works in TLS:

1. The server needs to generate once (for example, with openssl dhparam command):
   • p , a large prime number,
   • g , a primitive root modulo p (for every integer a coprime to p , there exists an integer k such that g^k=a\mod p ).
2. The server picks a random integer a and compute g^a \mod p . After sending its regular Certificate message, it will also send a Server Key Exchange message (not included in the handshake depicted above) containing, unencrypted but signed with its private key for authentication purpose:
   • random value from the Client Hello message,
   • random value from the Server Hello message,
   • p , g ,
   • g^a\mod p=A .
3. The client checks that the signature is correct. It also picks a random integer b and sends g^b \mod p=B in a Client Key Exchange message. It will also compute A^b\mod p=g^ ab \mod p which is the premaster secret from which the master secret is derived.
4. The server will receive B and compute B^a\mod p=g^ ab \mod p which is the same premaster secret known by the client.

Again, the private key is only used for authentication purpose. An eavesdropper will only know p , g , g^a\mod p and g^b\mod p . Computing g^ ab \mod p from those values is the discrete logarithm problem for which there is no known efficient solution. Because the Diffie-Hellman exchange described above always uses new random values a and b , it is called Ephemeral Diffie-Hellman (EDH or DHE). Cipher suites like DHE-RSA-AES128-SHA use this protocol to achieve perfect forward secrecy¹. To achieve a good level of security, parameters of the same size as the key are usually used (the security provided by the discrete logarithm problem is about the same as the security provided by factorisation of two large prime numbers) and therefore, the exponentiation operations are pretty slow as we can see in the benchmark below:

Diffie-Hellman with elliptic curves Fortunately, there exists another way to achieve a Diffie-Hellman key exchange with the help of elliptic curve cryptography which is based on the algebraic structure of elliptic curves over finite fields. To get some background on this, be sure to check first Wikipedia article on elliptic curves. Elliptic curve cryptography allows one to achieve the same level of security than RSA with smaller keys. For example, a 224bit elliptic curve is believed to be as secure as a 2048bit RSA key.

Some theory Diffie-Hellman key exchange described above can easily be translated to elliptic curves. Instead of defining p and g , you get some elliptic curve, y^2=x^3+\alpha x+\beta , a prime p and a base point G . All those parameters are public. In fact, while they can be generated by the server, this is a difficult operation and they are usually chosen among a set of published ones. The use of elliptic curves is an extension of TLS described in RFC 4492. Unlike with the classic Diffie-Hellman key exchange, the client and the server need to agree on the various paremeters. Most of this agreement is done inside Client Hello and Server Hello messages. While it is possible to define some arbitrary parameters, web browsers will only support a handful of predefined curves, usually NIST P-256, P-384 and P-521. From here, the key exchange with elliptic curves is pretty similar to the classic Diffie-Hellman one:

1. The server picks a random integer a and compute aG which will be sent, unencrypted but signed with its private key for authentication purpose, in a Server Key Exchange message.
2. The client checks that the signature is correct. It also picks a random integer b and sends bG in a Client Key Exchange message. It will also compute b\cdot aG=abG which is the premaster secret from which the master secret is derived.
3. The server will receive bG and compute a\cdot bG=abG which is the same premaster secret known by the client.

An eavesdropper will only see aG and bG and won t be able to compute efficiently abG . Using ECDHE-RSA-AES128-SHA cipher suite (with P-256 for example) is already a huge speed improvement over DHE-RSA-AES128-SHA thanks to the reduced size of the various parameters involved. Web browsers only support a handful of well-defined elliptic curves, chosen to ease an efficient implementation. Bodo M ller, Emilia K sper and Adam Langley have provided 64bit optimized versions of NIST P-224, P-256 and P-521 for OpenSSL. To get even more details on the matter, you can read the end of the introduction on elliptic curves from Adam Langley, then a short paper from Emilia K sper which presents a 64bit optimized implementation of the NIST elliptic curve NIST P-224.

In practice First, keep in mind that elliptic curve cryptography is not supported by all browsers. Recent versions of Firefox and Chrome should handle NIST P-256, P-384 and P-521 but for most versions Internet Explorer, you are currently out of luck. Therefore, you need to keep accepting other cipher suites. You need a recent version of OpenSSL. Support for ECDHE cipher suites has been added in OpenSSL 1.0.0. Check with openssl ciphers ECDH that your version supports them. If you want to use the 64bit optimized version, you need to run a snapshot of OpenSSL 1.0.1, configured with enable-ec_nistp_64_gcc_128 option. A recent GCC is also required in this case. Next, you need to choose the appropriate cipher suites. If forward secrecy is an option for you, you can opt for ECDHE-RSA-AES128-SHA:AES128-SHA:RC4-SHA cipher suites which should be compatible with most browsers. If you really need forward secrecy, you may opt for ECDHE-RSA-AES128-SHA:DHE-RSA-AES128-SHA:EDH-DSS-DES-CBC3-SHA instead. Then, you need to ensure the order of cipher suites is respected. On nginx, this is done with ssl_prefer_server_ciphers on. On Apache, this is SSLHonorCipherOrder on. UPDATED: You need to check ECDHE support for your web server. For nginx, the support has been added in 1.0.6 and 1.1.0. The curve selected defaults to NIST P-256. You can specify another one with ssl_ecdh_curve directive. For Apache, it has been added in 2.3.3 and does not exist in the current stable branch. Adding support for ECDHE is quite easy. You can check how I added it in stud. This issue also exists for DHE cipher suites, in which case you also might have to specify DH parameters to use (generated with openssl dhparam) using some special directive or by appending the parameters to the certificate. Check Immerda Techblog article for more background about this point. The implementation of TLS session tickets may be incompatible with forward secrecy, depending on how they are implemented. When they are protected by a random key generated at the start of the server, the same key could be used for months. Some implementations² may derive the key from the private key. In this case, forward secrecy is broken. If forward secrecy is a requirement for you, you need to either disable tickets or ensure that key rotation happens often. Check with openssl s_client -tls1 -cipher ECDH -connect 127.0.0.1:443 that everything works as expected.

Some benchmarks With the help of the micro-benchmark tool that I developed for my previous article, we can compare the efficiency of cipher suites providing forward secrecy: I have used a snapshot of OpenSSL 1.0.1 (2011/11/25). The optimized version of ECDHE is the one you get by using enable-ec_nistp_64_gcc_128 option when configuring OpenSSL. Let s focus on the server part. Enabling DHE-RSA-AES128-SHA cipher suite hinders the performance of TLS handshakes by a factor of 3. Using ECDHE-RSA-AES128-SHA instead only adds an overhead of 27%. However, if we use the 64bit optimized version, the cost is only 15%. The overhead is only per full TLS handshake. If 3 out of 4 of your handshakes are resumed, you need to adjust the numbers. Your mileage may vary but the computational cost for enabling perfect forward secrecy with an ECDHE cipher suite seems a small sacrifice for better security.

---

1. Perfect forward secrecy is an enhanced version of forward secrecy. It assumes each exchanged key are independent and therefore a compromised key cannot be used to compromise another one.
2. For example, this is the case of the implementation I have proposed for stud to enable sharing of tickets between multiple hosts.

I've released version 0.23 of Obnam, my backup application. USER VISIBLE CHANGES:

• restore now shows a progress bar.
• fsck now has more useful progress reporting, and does more checking, including the integrity of the contents of file content.
• fsck now also checks the integrity of the B-trees in the repository, so that it is not necessary to run fsck-larch manually anymore. This works remotely as well, whereas fsck-larch only worked on B-trees on the local filesystem.
• force-lock now gives a warning if the client does not exist in the repository.
• Subcommands for encryption now give a warning if encryption key is not given.
• The --fsck-fix option will now instruct obnam fsck to try to fix problems found. For this release, it only means fixing B-tree missing node problems, but more will follow.
• The default sizes have been changed for B-tree nodes (256 KiB) and file contents chunks (1 MiB), based on benchmarking.
• SFTP protocol use has been optimized, which should result in some more speed. This also highlights the need to change obnam so it can do uploads in the background.
• If a client does not exist in the repository, force-lock now gives a warning to the user, rather than ignoring it silently.

DEVELOPER CHANGES:

• New --sftp-delay=100 option can be used to simulate SFTP backups over networks with long round trip times.
• obnam-benchmark can now use --sftp-delay and other changes to make it more useful.

INTERNAL CHANGES:

• Got rid of terminal status plugin. Now, the Application class provides a ttystatus.TerminalStatus instance instead, in the ts attribute. Other plugings are supposed to use that for progress reporting and messaging to the user.
• The posix_fadvise system call is used only if available. This should improve Obnam's portability a bit.

Slovak complete for all levels. Norwegian Bokm l completes level 1. Full stats are here Status for D-I level 1 (core D-I files):

• 25 languages 100% for all sublevels: bg bscs de eo es fa fr gu hi it ja ko mr nb nl pl pt ru si sk ta te th zh_CN
• 1 language 98%: sv
• 1 language 97%: eu
• 1 languages 96%: tr
• 6 languages 95%: be bn dz he kk uk
• 4 langauges 94%: ar ast ga ro
• 4 languages 93%: el hu km lo
• 2 languages 92%: id sl
• 4 languages 91%: et pa vi zh_TW
• others are 90% or below

Status for D-I level 2 (packages that have localized material that may appear during default installs, such as iso-codes, tasksel, etc.):

• 9 languages 100%: de es fa fr pt ru si sk zh_CN
• 13 languages 99%: be cs da eo id it ja kk nl sl sv th uk
• 5 languages 98%: bg ca eu pt_BR ro
• 4 langauges 95%: el fi he nb
• 7 languages 94%: ar ast dz gl hr vi zh_TW
• 1 language 93%: is
• 7 languages 92%: bn bs hu ko ne pl tr
• 10 languages 91%: ga gu ka km lt mk mr sr ta te
• others are 90% or below

Status for D-I level 3 (packages that have localized material that may appear during non-default installs, such as win32-loader)

• 9 languages 100%: cs de fa fr nl pt ru sk sv
• 16 languages 99%: be bg bs ca el eo es fi ga gl he is ja th tr zh_CN
• 2 languages 97%: hu uk
• others are 90% or below

So, full 100% completeness (hall of fame) for: German (de), Persian (fa), French (fr), Portuguese (pt, Russian (ru), Slovak (sk)

Slovak complete for all levels. Norwegian Bokm l completes level 1. Full stats are here Status for D-I level 1 (core D-I files):

• 25 languages 100% for all sublevels: bg bscs de eo es fa fr gu hi it ja ko mr nb nl pl pt ru si sk ta te th zh_CN
• 1 language 98%: sv
• 1 language 97%: eu
• 1 languages 96%: tr
• 6 languages 95%: be bn dz he kk uk
• 4 langauges 94%: ar ast ga ro
• 4 languages 93%: el hu km lo
• 2 languages 92%: id sl
• 4 languages 91%: et pa vi zh_TW
• others are 90% or below

Status for D-I level 2 (packages that have localized material that may appear during default installs, such as iso-codes, tasksel, etc.):

• 9 languages 100%: de es fa fr pt ru si sk zh_CN
• 13 languages 99%: be cs da eo id it ja kk nl sl sv th uk
• 5 languages 98%: bg ca eu pt_BR ro
• 4 langauges 95%: el fi he nb
• 7 languages 94%: ar ast dz gl hr vi zh_TW
• 1 language 93%: is
• 7 languages 92%: bn bs hu ko ne pl tr
• 10 languages 91%: ga gu ka km lt mk mr sr ta te
• others are 90% or below

Status for D-I level 3 (packages that have localized material that may appear during non-default installs, such as win32-loader)

• 9 languages 100%: cs de fa fr nl pt ru sk sv
• 16 languages 99%: be bg bs ca el eo es fi ga gl he is ja th tr zh_CN
• 2 languages 97%: hu uk
• others are 90% or below

So, full 100% completeness (hall of fame) for: German (de), Persian (fa), French (fr), Portuguese (pt, Russian (ru), Slovak (sk)

While working on SAT-Britney, I made heavy use of the IntSet data type provided by the basic Haskell library containers . Since memory consumption was a problem, I looked at its implementation, which is a binary tree, and wondered whether this could be improved for dense sets by using a machine sized word as a bit map to represent a continuous part of the integers, so I started to implement it. The effect on my program was not as strong as I had hoped for, but nevertheless, the code made its way back into containers after a thorough review and a considerable amount of further improvements by Milan Straka. I m getting sucked deeper and deeper into the Haskell community... (which means that the Haskell community does not suck, of course.)
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It s been one year since the first People behind Debian interview. For this special occasion, I wanted a special guest and I m happy that our Debian Project Leader (DPL) Stefano Zacchiroli accepted my invitation. He has a difficult role in the community, but he s doing a really great job of it. He s a great mediator in difficult situations, but he s also opinionated and can push a discussion towards a conclusion. Read on to learn how he became a Debian developer and later DPL, what he s excited about in the next Debian release, and much more. Raphael: Who are you? Stefano: I m Stefano Zacchiroli, but I prefer to be called Zack, both on the Internet and in real life. I m 32, Italian, emigrated to France about 4 years ago. I live in Paris, and I find it to be one of the most gorgeous and exciting cities in the world. As my day job I m a Computer Science researcher and teacher at University Paris Diderot and IRILL. In my copious free time I contribute to Debian, and I m firmly convinced that doing so is an effective way to help the cause of Free Software. Besides, I find it to be a lot of fun! Raphael: How did you start contributing to Debian? Stefano: Flash back to 1999, when I was a 2nd year student in Computer Science at the University of Bologna. Back then in Italy it was uncommon for young geeks to get exposed to Free Software: Internet was way less pervasive than today and most computer magazines didn t pay much attention to GNU/Linux. Luckily for me, the professor in charge of the student lab was a Free Software enthusiast and all students machines there were running Debian. Not only that, but there was also a student program that allowed volunteers to become sysadmins after having shown their skills and convinced the director they were trustworthy. Becoming one of those volunteer Debian admins quickly became one of my top objectives for the year, and that is were I ve learned using Debian. The year after that, I got in touch with a research group that was to become the happy bunch of hackers with whom I would have done both my master and PhD theses. They were designing a new proof assistant. Most of the development was in OCaml and happened on Debian. OCaml was available in Debian, but many of the libraries we needed were not. So I approached the Debian OCaml Team offering to help. Before I realize what was going on I was (co-)maintainer of tens of OCaml-related packages. At some point I got told I think you should apply as a Debian Developer . So I did and in a couple of months I went through the New Member (NM) process, that was back then in its infancy. I still remember my happiness while reading the account created mail, the day after my 22nd birthday. I know the NM process went through some bad publicity in the past, but I m happy to see that nowadays the process can be as swift as it has been for me 10 years ago. Raphael: It s your second year as Debian Project Leader (DPL). Are you feeling more productive in the role? Do you fear to burn out? Stefano: I m feeling way more productive, no doubts. The task of the Debian Project Leader is not necessarily difficult, but it is a complex and scarcely documented one. It is also profoundly different from any other task that Debian people usually work on, so that experience doesn t help much in getting started. Before becoming effective as DPL one needs to get to know many people and mechanisms he is not familiar with. More importantly, one needs to set up a personal work-flow that allows to keep up with day-to-day DPL tasks (which are aplenty) as well as with urgencies (that tend to pop-up in the leader@debian.org INBOX at the least convenient time). Finally, one also needs to do proper traffic shaping and always retain enough motivation bandwidth to keep the Project informed about what is going on in DPL-land. Finding the right balance among all these ingredients can take some time. Once one is past it, everything goes way more smoothly. The above is why I m constantly encouraging people interested in running for DPL in the future to reach out to me and work on some tasks of the current DPL s TODO list. I swear it is not just a cheap attempt at slavery!. It is rather an attempt at DPL mentoring that could be beneficial: both to give future candidates more awareness of the task, and to reduce the potential downtime when handing over from one DPL to the next. Regarding burn out, I don t feel prone to its risk these days. If I look back, I can say that my contributions as DPL have been pretty constant in volume over time; my enthusiasm for the task, if anything, is on the rise. The effectiveness of my contributions as DPL are, on the other hand, not mine to judge. Raphael: If you had to single out two achievements where you were involved as DPL, what would they be? Stefano: I d go for the following two, in no particular order:

• Dialogue with derivatives. When I became DPL ~1.5 years ago the situation on that front was pretty dire. In the specific case of Ubuntu, by far the most successful and customized of all Debian derivatives, I remember being scared of raising the topic of collaboration with them on mailing lists. More generally, we had no specific initiatives to foster technical collaboration with and among derivatives. A huge potential of (forwarded) contributions to Debian was being wasted. Today things look much better, as I ve documented in recent talks at DebConf11 and UDS-P. The amount of forwarded patches we receive from downstream is at its maximum and many people who apply to become Debian Developers come from derivatives. Conflict situations still exist, for good reasons that we still have to either fix or figure out entirely. But I m positive we re on the right track.

  The amount of forwarded patches we receive from downstream is at its maximum

  This is by far not an achievement of mine alone. In particular, many of the activity of the Derivatives Front Desk have been organized by other enthusiastic volunteers. But I ve done my part, especially in breaking the ice and in proposing a vision of Free Software distribution where all distros play a role and are welcome to join the game, as long as they give back and give credit to their respective upstreams.
• Process membership. I m proud of having promoted the general resolution (GR) that has clarified (and advertised to the world) that Debian welcomes all kind of contributions, and that they all equally matter to become proper members of the Project. I notice only now while writing this that the GR title, traditionally chosen by the secretary, was Debian Project Members . That choice harmonically closes the circle with the recent renaming of the NM process to New Member process. Today, we have several project members (AKA Debian Developers ) that are active citizen of Debian with voting rights, even though they take care of tasks other than packaging. Anyone can become a Debian citizen, as long as they are ready to abide by Debian s values, have a track record of verifiable contributions to Debian, and are committed to keep them coming in the future.

  We have several project members that [ ] take care of tasks other than packaging.

  Once gain, this is by far not an achievement of mine alone, very little project-wide achievements are. DAM has helped a lot and support from the project as a whole has been immense.

OK, let me cheat and add a third one I m also proud of having been able to report to the Project my whereabouts as DPL, thoroughly and periodically, since the very beginning is first term. People annoyed by my reporting logorrhea now have all my sympathies. Raphael: Among the possible new features of Debian Wheezy, which one gets you excited most? Stefano: It s multi-arch, no doubt. Even though it is not a directly user visible change, it s a very far reaching one. It is also one of those changes that make me feel that moment of truth of coders, when you realize you are finally doing the right thing and ditching piles of ugly hacks.

It s multi-arch [ ] you realize you are finally doing the right thing and ditching piles of ugly hacks.

Raphael: If you were not DPL and could spend all your time on Debian, what project would you do? Stefano: I would sit down and do software development for Debian. It s impressive how many important and beneficial changes for Debian could be delivered by specific software improvements in various parts of our infrastructure. We tend to attract many packagers, but not so many people willing to maintain Debian infrastructure softwares like dak, britney, debbugs, the PTS, etc. Their maintenance burden then falls on the shoulders of the respective teams which are generally very busy with other important tasks. As a project, we seem to be more appealing to packagers than to software developers. That is a pity given the amount of exciting coding tasks that are everywhere in Debian. Part of the reason we are not appealing to developers is that we are not particularly good at collecting coding tasks in a place where interested developers could easily pick them up. It also takes quite a bit of inside knowledge to spot infrastructure bugs and understand how to fix them. I long for some spare hacking time to check if I m still good enough of a coder to hunt down longstanding bugs in our infrastructure, which have ended up being my pet peeves. I d also love to dive again into RCBW. It s less committing than package maintenance, more diverse and challenging, and also an immensely useful activity to get Debian releases done. Raphael: Martin Michlmayr is worried that there is so few paid opportunities around Debian. Do you agree with his sentiment, and if yes do you have ideas on how to improve this situation? Stefano: The idealistic me wishes Debian to be a community made only of volunteers that devote their free time to the Project. Oh, and that me also wishes Debian to be competitive with similar projects, no matter how many full-time employees others have! That is coherent with a view of society where everyone has a day job, but also engages in volunteering activities ensuring that public interest is pursued by people motivated by interests other than profit. But I do realize that for Free Software to succeed companies, employees, and salaries should all have a role. I admire projects that strike a good balance between volunteer and paid work. The Linux kernel is emblematic in that respect: many developers are paid by companies that have a commercial or strategic interest in Linux. Nevertheless volunteers contributions are aplenty and the Linux community gives a convincing impression that choices are driven by the community itself (or by its benevolent dictator) without money-driven impositions.

I do realize that for Free Software to succeed companies, employees, and salaries should all have a role.

Such an ecosystem does not exist around Debian. We do have a partner program that allows for it to happen, but we have very few partners with an interest in doing distribution development work. Like Martin, I m worried by this state of affairs, because it de facto means we lag behind in terms of available people power. In a community of volunteers, that might frustrate people and that is not good. To improve over the status quo the first step is to federate together small and medium companies that have a strategic interest in Debian and listen to their needs. I m already in touch with representatives of such companies that, in many cases, already employ Debian Developers to do some distribution work in Debian. We will be soon sending out a call to reach out to more such companies, but since we are discussing this, why waiting? If some of our readers here are representative of such companies, I encourage them to get in touch with me about this. Raphael: You know that the fundraising campaign for the Debian Administrator s Handbook is on good track but the liberation of the book is not yet assured. What do you think of this project? Stefano: I m happy about the project, to the point that I ve accepted writing a testimonial for it . I m sad about the scarce availability of up to date and high quality (DFSG-)Free books about Debian and I welcome any initiative that might help closing that gap.

I m sad about the scarce availability of up to date and high quality (DFSG-)Free books about Debian.

Free Culture is a great offspring of Free Software and I m convinced we need to stand up against double standards in the two camps. Letting aside software-specific licensing details, the basic freedoms to be defended are the same. They are those freedoms that ensure that a reader is in full control of his book, pretty much as they ensure that a computer user is in full control of the software that runs on it. I m therefore proud that Debian has long resolved that the Debian Free Software Guidelines (DFSG) apply not only to software but also to books and other pieces of documentation. But the status quo implies that not only we have very few up to date, high quality books about Debian. It also implies that, at present, we have no such book that we can distribute in the Debian archive, showing off the Free Software (and Free Culture!) values we stand for.
Crowdfunding is considered to be a good mate for Free Culture, where the services model that applies to Free Software is more difficult to exploit. I so wish any luck to yours and Roland s initiative. A different matter is whether Debian, as a project, should endorse the initiative and actively campaign for it. As you know, I think it should not. While we do advertise general project donations, we don t do mission-specific fundraising campaign for Debian itself. Coherently with that, I don t think we should relay crowdfunding campaigns for 3rd parties, even when the result would be beneficial to Debian. Raphael: Is there someone in Debian that you admire for their contributions? Stefano: There are two classes of people that I particularly admire in Debian:

• Those with an uncanny ability to guide discussions towards constructive conclusions. We are lucky to have many in Debian and I admire all of them. Having to single out one I d name Russ Allbery, in honor of whom I hereby propose the periodic Russ Allbery s Distinguished Flametamer Award .
• People stepping up for responsibility roles, especially when the responsibility put them in tough spots. Release teams, ftp-masters, DSA, DAM, as well as past and present members of teams with similarly hot seats have all my admiration.

---

Thank you to Zack for the time spent answering my questions. I hope you enjoyed reading his answers as I did.

Subscribe to my newsletter to get my monthly summary of the Debian/Ubuntu news and to not miss further interviews. You can also follow along on Identi.ca, Google+, Twitter and Facebook .

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Since I think I just summarized a few thoughts of mine well at LWN, I'll copy-paste it here:

I can grumble about Android from time to time, but I do not say that it sucks. Extreme views are what are annoying. Android is what it is and it's great as it is, even though it could be different as well.

When it comes to discussing about free software and mobile phones, I'm especially annoyed by two types of comments:

1. People essentially saying that there is no value in an open project, ie. free software code dumps should be enough for everybody. I'm interested in the long term viability of free software projects, and it is hard to have successful projects without there being all sorts of factors that make up a good project - like transparency, inclusion, meritocracy. Even though the mobile projects have had little resources and a hard road, it's not useful to forget about these goal in the longer term. For example Debian, Mer, SHR, KDE Plasma Active have some of these in the mobile sector. I hope the best for them (and participate).

2. People complaining about something being not 100% free software, while not themselves actually even interested in it for other sake than complaining. When I've been talking about free software mobile phones, from time to time there is someone complaining about eg. not open GSM stack, wlan firmwares etc.. and to put it sharply probably writing the message from iPhone, while I'm reading it on Neo FreeRunner. If the complainer would be Harald Welte, I'd probably listen and agree with him.

So there. For more civilized discussion.

Bosnian, Hindi, Marathi complete level 1. Slovak completes level 3. Full stats are here Status for D-I level 1 (core D-I files):

• 24 languages 100% for all sublevels: bg bscs de eo es fa fr gu hi it ja ko mr nl pl pt ru si sk ta te th zh_CN
• 1 language 98%: sv
• 1 language 97%: eu
• 1 languages 96%: tr
• 6 languages 95%: be bn dz he kk uk
• 4 langauges 94%: ar ast ga ro
• 5 languages 93%: el hu km lo nb
• 2 languages 92%: id sl
• 4 languages 91%: et pa vi zh_TW
• others are 90% or below

Status for D-I level 2 (packages that have localized material that may appear during default installs, such as iso-codes, tasksel, etc.):

• 8 languages 100%: de es fa fr pt ru si zh_CN
• 14 languages 99%: be cs da eo id it ja kk nl sk sl sv th uk
• 5 languages 98%: bg ca eu pt_BR ro
• 4 langauges 95%: el fi he nb
• 7 languages 94%: ar ast dz gl hr vi zh_TW
• 1 language 93%: is
• 7 languages 92%: bn bs hu ko ne pl tr
• 10 languages 91%: ga gu ka km lt mk mr sr ta te
• others are 90% or below

Status for D-I level 3 (packages that have localized material that may appear during non-default installs, such as win32-loader)

• 9 languages 100%: cs de fa fr nl pt ru sk sv
• 16 languages 99%: be bg bs ca el eo es fi ga gl he is ja th tr zh_CN
• 2 languages 97%: hu uk
• others are 90% or below

So, full 100% completeness (hall of fame) for: German (de), Persian (fa), French (fr), Portuguese (pt, Russian (ru)

A few snippets so far from our train trip from Kansas to Portland. Terah, Jacob, Oliver, and I are on the trip, which is about 2.5 days on the train. The Parenting Dilemma So, if you are eating dinner, and your 5-year-old falls asleep with his head on the table, and you know he had been excitedly waiting for raspberry sorbet for dessert, and know there will be tears when he later realizes he missed it, what do you do? Let him sleep, or wake him up (with possible tears right then in the dining car?) As it turned out, I tried to quietly ask him if he wanted dessert. He woke up with a start, banged his head on the table, and then, yes, there were tears. I asked him if he wanted dessert or if he wanted to keep sleeping, and he gave a pathetic, sniffling, dessert. But by the time dessert arrived, he had fallen asleep again. I finally woke him up again, asked if he wanted to eat, and he just ignored me. I asked twice more and then he all of a sudden realized what he was being asked, sat bolt upright, and dug in. Graffiti Jacob noticed graffiti in Los Angeles. He called it silly words and kept commenting about it as we passed it. Bears Oliver always sleeps with a stuffed bear, which is his favorite comfort animal. But Oliver is 2, and when he says bear , it sounds more like beer . Plus, the boys still seem to be operating on Central Time. So at 4:15AM yesterday, Oliver awakened us saying: Beer! Beer! Beer! Where s beer? Where s beer? Need beer! Beeeeeer! Butterflies Jacob always sleeps with a stuffed butterfly, which he likes just like Oliver likes his bear. Jacob had this conversation with me this morning: Jacob: My butterfly knows all the people in the world. And all the animals, too! Me: Does butterfly even know Nash? (our cat) Jacob: Yeah, and he knows Sam and Edna too! (the cats across the road) Me: Wow. I think butterfly knows a lot more people and animals than I do. Jacob: *brief pause, then* Oh, silly dad! *collapses laughing*

There's been a lot of noise with Microsoft requiring Secure Boot for Windows 8 OEMs. For those of you unfamiliar with it, Secure Boot requires that the boot chain is signed, and this 'feature' must be enabled by default. Although I have been unable to find specific details, it appears that the chain of trust needs to extend from BIOS/UEFI all the way down to the kernel. Obviously, requiring a signed boot chain makes using FOSS platforms like Ubuntu or Debian an impossibility short of having the UEFI Platform Key and resigning the entire chain.

Steven Sinofsky's MSDN blog has a fairly good overview how it works. Canonical and Red Hat also have a good white paper on why secure boot is a serious problem for Linux distributions. Even if secure boot itself can be disabled, it *greatly* rises the bar for general end-users to successfully install Ubuntu on their machine. In addition, it is the responsibility of OEM and BIOS manufacturers to provide the option to disable it.

There already has been a long history of OEMs removing BIOS options or introducing DRM; for instance, locking out VTx on Sony laptops, or restricting laptops to only accept 'branded' wifi and 3G cards. Given this track record, can OEMs realistically be trusted to have this option available?

What most people don't realize is that secure boot itself is not a new concept; its simply part of the Trusted Computing initiative, and has been implemented on embedded platforms for many years. If you own any iPhone, or one of the vast majority of Android devices, you are using a device that either has the secure boot feature, or something very close. This especially painful in Android as Google's security system restricts users to a *very* limited shell and subset of utilities which can be used on non-rooted devices. WebOS, Maemo, and to my knowledge Meego give the end-user full unrestricted access to the boot chain and you can swap kernels and even the entire OS out if one was so motivated.

Although it is still an ongoing problem, several vendors such as HTC, Samsung, Motorola (kinda), and even Sony. In the Android community, having unlockable bootloaders has been a welcome middle ground in the traditionally restrictive and locked-down world of cellular devices.

While some may argue that such locks are necessary to protect consumers, it is perfectly feasible to create devices with unlocked bootloaders that are still secure. The Nook Color's is an Android powered eReader. It's stock firmware doesn't allow sideloaded applications or even access to a user shell via adb, but the BootROM on the device attempts to boot from the microSD card before eMMC, making it possible for enterprising users to easily modify the underlying OS (as well as making it physically impossible to brick the device due to a bad flash). Barnes and Nobles even sells a book on rooting the Nook Color; it was right next to the devices on display at the time. In addition, they've continued the tradition of easily modifiable devices with both the Nook Simple Touch, and the Nook Tablet.

One of the most impressive attributes is the possibility of running Ubuntu on it. The absolute poster child for this is the Toshiba AC100. For those of you unfamiliar, it ultralight netbook that shipped with Android 2.1/2.2 with easy access to the built in flash via the mini-USB port on the side of the device. Due to the valiant efforts of the AC100 community, Ubuntu was ported to this device, and became a supported platform with images available on cdimages.ubuntu.com. If you were an attendee at UDS, you likely saw several AC100s all running Ubuntu.

This brings me to the point that motivated me to write this post in the first place. One of the most impressive tablets I've seen to date is the ASUS eeePad Transformer, an Android tablet with fully dockable keyboard. I have one of these devices, and its one of the most impressive and usable Android tablets I own. Sadly, such a powerful device was hobbled from its true potential due to ASUS's decision to ship the device with a locked and encrypted bootloader. Surprisingly, the Secure Boot Key (SBK) was acquired and released to the wild, making it possible to reflash the device. Sadly, even with the SBK, the device's bootloader is still extremely hobbled compared to the AC100 making flashing a slow and difficult process.

In response, ASUS refreshed the eeePad's hardware to the new B70 SKU, which has a new Secure Boot. Despite this, a root exploit was recently found to allow people to circumvent these restrictions and install customs ROMs. It is however only a manor of time before ASUS responds and releases a new update that fixes this bug.

Steven Barker (lilstevie) on xda-developers successfully created a port of Ubuntu to the Transformer. Currently, installing Ubuntu on the Transformer requires nvflash access, so its not possible to use his image on the newly liberated B70 devices. I am certain that a new method of installing via an update.zip will be developed for those of us with hobbled devices.

It is a showcase of what is possible when you have open hardware, and also proves one indisputable point: any 'trusted boot' or DRM scheme can and will be defeated; at best you piss off your userbase, and at worst, you force users to exploit bugs to gain control of their device. As it is impossible to reflash these devices from the bootloader, a failed kernel flash WILL brick these devices, increasing warranty and support costs as users try to return their now broken devices.

In closing, while there have been some victories in ongoing war of open hardware vs. trusted comptuing, the road ahead still remains very murky. Victories in the mobile market have shown that there is a market for open devices. Google's own Nexus One was sold as a developers phone and as a way to encourage manufacturers to raise the bar. It sold well enough to recoup its development costs.. While there is no official statements, the Nokia N900 is suspected to have broken all sales expectations, backed up by the fact that Angry Birds sold extremely well on the Ovi Store for the N900.

From the article in question:

What reaction have you had in terms of sales and customer feedback?

Angry Birds had already been launched on App Store before it came out on Ovi Store, and it had a great review average from iPhone reviewers and users alike, so we expected a good reception from N900 users as well.

Even so, we were quite surprised by just how the N900 community immediately took the game to heart. The game obviously made many people very happy, and that is really the greatest achievement that anyone who creates entertainment for a living can hope for. Well, maybe the greatest achievement is huge bundles of cash, but making people happy comes a close second.

In the first week that Angry Birds has been on the Ovi Store, it has been downloaded almost as many times as the iPhone version in six weeks. Given that most N900 users have not even used Ovi Store yet, we are confident that there will be many more downloads in the months to come, and are sure that the N900 version will be very profitable.

That being said, with Microsoft pushing secure boot and trusted computing down everyone's throats with Windows 8, it is hard to say what the future might hold for those of us who want to own our devices.

Recently my installation of Qt SDK I use for development of applications for Nokia N950 (N9) got broken. It happened by update some postinst script failed what caused almost no part of Harmattan SDK to be installed. I hoped this to be temporary error which will get fixed by later updates, but it turned out to persist even for 1.1.4 which has been released week ago. Yesterday I finally got time to look into it and after some debugging I found out that it was trying to install x86_64 version, which was not downloaded because I was using 32bit installer. I quickly realized this was caused by using 64-bit kernel, while running 32-bit userspace, for which the installer somehow was not prepared. Fortunately there is easy workaround for that:

linux32 ./Qt_SDK_Lin32_online_v1_1_4_en.run

What will run the binary in 32-bit personality and make kernel pretend it is compiled for 32-bit.

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We've had sporadic Altus Metrum customer reports about RF susceptibility issues with their TeleMetrum installations. In almost every case, these problems have been completely resolved by either making sure the system battery has sufficient charge before launch, or through the application of standard engineering techniques such as twisting wire pairs to reduce differential coupling. However, even when every technique we could think of had been applied, once in a while someone still had issues. Around the time of LDRS this year, the incidence of such reports seemed to increase. One customer, in particular, had an installation in which he virtually always saw continuous resets of the board once his 54mm airframe was put on a launch rail, and several customers reported seeing board resets during ejection charge firing. Keith and I saw a board reset during main charge firing happen in person at NCR's Oktoberfest, and with a couple days available to work together after that launch, we decided it was time to figure out what was really going on. Here's what we've learned. In bench testing, it quickly became clear that the problem was the 3.3 volt power supply rail getting pulled down far enough to reset the CPU. This most frequently happened during ejection charge firing, when the input of the LDO regulator is pulled down by the near-short presented by the e-match when a pyro FET is turned on. To keep the 3.3 volt rail voltage up during firing, we include a 100uF bulk capacitor on the regulator's output. In all of our prior bench testing, we never saw the 3.3 volt rail droop significantly. Clearly something had changed... or maybe several things had changed? The first thing I wondered about was whether the new Kalman filtering code, which requires more compute cycles from the processor, might be consuming enough more power to pull the rail down faster during charge firing. After poking around at it, though, we have no data to suggest the new code makes a measurable difference in power consumption. The next thing we pondered was that at least some of the e-matches we and others are using in the hobby now come from the fireworks industry, where it is apparently considered a feature for the match to retain continuity after firing. This means the input of the LDO gets held down for longer than with the e-matches we used to use and Quest Q2G2 igniters that open when fired. But that still didn't make sense as the root cause, as we chose the FET firing time such that even with a dead short across the igniter terminals, the 3.3 volt rail wouldn't be pulled down far enough to cause trouble during firing. One of the big changes between v1.0 and v1.1 on TeleMetrum was that the newer boards incorporate a better reset circuit. This helps ensure the GPS chip always comes up running at power on, which was a problem at temperature extremes with older boards. However, a side-effect of this change is that a v1.1 board will reset any time the 3.3 volt rail drops below 3.15 volts, whereas older boards didn't trip until a much lower voltage. So the recent increase in reports might just be related to more v1.1 boards being placed in service? While experimenting on the bench, we observed that injecting RF energy into the input of the LDO regulator had the effect of pulling down the output voltage, presumably because the internal reference source accumulates charge and is fooled into thinking the output is too high. Since our designs all have the power switch contacts ahead of the LDO, the wires going out to the switch and back are effectively an antenna... as are, to a lesser extent, the wires going to the e-matches. There is some variability from part to part in just how badly the LDO reacts. But by attaching a tuned length of wire as an antenna to the LDO input and playing around, we were finally able to reproduce the problem reliably on a test board at my bench! On further analysis, we realized that the output of the USB battery charger chip and the input of the LDO both expect a 1uF bypass cap to ground. At some point, those looked redundant and we eliminated one of the two. Unfortunately, we weren't internalizing the fact that the switch leads were between the two caps, and the one we left was on the output of the charger and not at the input of the LDO. Placing a suitable bypass cap right at the input of the LDO turns out to have a truly dramatic effect on RF immunity! Once we realized that RF getting into the LDO input was the problem, Keith pointed out that we used to see "noise" in the accelerometer data on earlier boards that was caused by the 3.3 volt rail moving slightly during radio transmit, which we fixed with a hardware change on v1.1. We are now convinced that this was at least partly related to RF coupling to the LDO input, not just the change in power consumption on the LDO output. We didn't realize what was going on in earlier testing because we often didn't have ematches wired up, so RF coupling was minimal. But going back to flights logged with v1.0 boards that included deployment, and studying the magnitude of the "steps" in acceleration data observed when the transmitter was on, Keith was able to compute the amount the 3.3 volt rail must have sagged if the real acceleration wasn't changing... which in some cases was as much as 180mV! We think this proves that RFI could cause the LDO to drop its output voltage below the reset controller set point on v1.1 boards. Based on these observations, I'm making two hardware changes for the next version of TeleMetrum (version 1.2), and Keith is also making a software change. We have tested all of these changes on real boards both on the bench and in test flights, and the net effect is a major improvement in the RF immunity of TeleMetrum. The first hardware change is moving to a slightly lower trip voltage on the reset controller. Instead of 3.15, the new part trips at 3.00 volts nominal. This gives us more "headroom" to tolerate 3.3 volt rail droop during charge firing, and will allow the board to operate longer on a given battery charge. This change is not relevant for v1.0 and prior. The second hardware change is adding an appropriate bypass capacitor right at the LDO input. This requires a PCB update, but it's possible for me to update existing production boards by adding an 0402 cap right across the appropriate pins on the regulator chip. The software change prevents our altimeters from turning on the radio transmitter while an ejection charge is firing. Since the RF transmitter draws substantial additional power, this should help keep the 3.3 volt rail from drooping. This may not really matter, but it feels like the right thing to do. This change will be part of our next stable firmware release. We think most TeleMetrum customers need not worry about these updates. But if you have seen odd resets on the rail or during ejection charge firing in flight with a TeleMetrum v1.1, feel free to contact me about updating your existing board to include these improvements.

Two days ago, I finally brought my system up-to-date with regard to the GNOME packages that I use. I was very reluctant because I am using a heavily customized gnome-panel and I waited until all the applets that I use have been ported to gtk3 and the libgnome-applet library. I am the Debian maintainer of one of these applets, link-notification-daemon, and I have made the changes and tested them in a chroot before, but now that I am actually using it, I found and fixed more visual glitches. I think by now it is as usable as it was before on GNOME 2. I am still looking for someone to step up as the new upstream maintainer for it! I had some trouble with gnome-session and notification-daemon, thought I found the cause and reported it, but a day later I could not reproduce it anymore. Weird. Other problems, such as the busy cursor not disappearing after the session start, or evolution going into a freeze also have stopped occurring by themselves.
Other problems I found and fixed, for example the battery status applet was not visible until a major state change, or panel applets were not loaded due to a race condition, or tooltips not working (which called for a fix in gtk+ itself). I also added to the xmonad package the files required to allow the user to select GNOME with Xmonad in GDM, and found out how to have Galeon appear in the list of possible default browsers.
I don t really have to say much about GNOME3 itself. I disliked the default font, Cantarell, mostly because of the extra spacing that reduced the number of folders and mail I can see in evolution. (Also see what nekohayo has to say about that.) I also was under the impression that the font is much lighter, and I started to adjust the position of my laptop monitor to increase the contrast. So I switch back to DejaVu Sans.
I also disabled the sleep-on-lid-close feature I often run backups, or download stuff, or compile stuff, or calculate stuff, so I want better control over this. So, I guess, now that everything is almost as it was in GNOME2, I can say I like it...

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Today I was removing KDE from my laptop, when I realized that kde-window-manager would not go away (even when it was automatically installed) since it provides x-window-manager, which is needed by gdm. I manually removed it, but that got me thinking that maybe I had other packages that were in this situation. So I picked aptitude and tried to build some search-fu. Here is the resulting query:

aptitude search '?for x:

 ?x:installed

 ?x:automatic

 ?x:provides(?virtual ?reverse-depends(?installed))

 ?not(?x:reverse-depends(?installed(?depends(?=x))))'

Now, lets go over the query. The first part ?for x: allows us to refer to the package currently being matched. See the documentation for details. We'll see later why we need this. Basically we are saying: give me all packages x that match the following pattern. The second and third parts are trivial: we only want automatically installed packages.
The fourth part, ?x:provides(?virtual ?reverse-depends(?installed)) was easy: find all packages that provide a virtual package that is depended upon by some other installed package.
The fifth and final part, ?not(?x:reverse-depends(?installed(?depends(?=x)))) is why we needed the bound variable x. We want to filter out (hence the ?not) the packages that have some reverse dependency that depends directly on the package x. That way, in my case, metacity won't show up since gnome-core directly depends on it and is installed.

Unfortunately, this query doesn't grok alternative dependencies. For example, if gnome-core depended on metacity x-window-manager then this query wouldn't show metacity, since it is depended upon by a package. If someone can make this query understand that so that it only eliminates packages directly depended upon with no alternatives dependencies, please let me know!Tags: aptitude, cleaning, tip, tips

Sinhala and Slovak reach 100% for level 1. Full stats are here Status for D-I level 1 (core D-I files):

• 21 languages 100% for all sublevels: bg cs de eo es fa fr gu it ja ko nl pl pt ru si sk ta te th zh_CN
• 1 language 98%: sv
• 1 language 97%: eu
• 2 languages 96%: hi tr
• 6 languages 95%: be bn bs dz kk uk
• 3 langauges 94%: ast ga ro
• 5 languages 93%: el hu km lo nb
• 2 languages 92%: id sl
• 5 languages 91%: et mr pa vi zh_TW
• others are 90% or below

Status for D-I level 2 (packages that have localized material that may appear during default installs, such as iso-codes, tasksel, etc.):

• 8 languages 100%: de es fa fr pt ru si zh_CN
• 14 languages 99%: be cs da eo id it ja kk nl sk sl sv th uk
• 5 languages 98%: bg ca eu pt_BR ro
• 4 langauges 95%: el fi he nb
• 7 languages 94%: ar ast dz gl hr vi zh_TW
• 1 language 93%: is
• 7 languages 92%: bn bs hu ko ne pl tr
• 10 languages 91%: ga gu ka km lt mk mr sr ta te
• others are 90% or below

Status for D-I level 3 (packages that have localized material that may appear during non-default installs, such as win32-loader)

• 8 languages 100%: cs de fa fr nl pt ru sv
• 17 languages 99%: be bg bs ca el eo es fi ga gl he is ja sk th tr zh_CN
• 2 languages 97%: hu uk
• others are 90% or below

So, full 100% completeness (hall of fame) for: German (de), Persian (fa), French (fr), Portuguese (pt, Russian (ru)

It s seeming increasingly likely that reports regarding the future of Banshee, Tomboy, and the rest of the Mono stack in the default Ubuntu desktop install are accurate. Ubuntu 12.04 will likely be the first Ubuntu release since 5.10 not to ship with any Mono apps in the default install ending a run of 12 releases over 6 years. The decision seems to have come about during the default apps session at the Ubuntu Developer Summit just ended in Orlando, Florida. Prior to heavy vandalism, the only reasons cited for the change in the UDS session log are Banshee not well maintained and porting music store to GTK3 is blocked on banshee ported to GTK3 . Other reasons mentioned but not in the session logs are complaints that it doesn t work on ARM. I m using a lot of conjecture in this first paragraph because the news about the decision appeared on the blogosphere before anywhere else. The first many Banshee or Tomboy developers read about it was reading a flurry of activity on the Tweetosphere from the anti-Mono activists declaring victory. So first, a word on the cited reasoning. Banshee works fine on ARM, since Mono works fine on ARM. Xamarin, the company behind most upstream Mono work, earns their income almost entirely from ARM versions of Mono, running on the varied ARM implementations found in smartphones. Every major Banshee release is personally tested on my Genesi EfikaMX, an ARM system with a Freescale i.mx51 processor. I ve also demonstrated Banshee running in an Ubuntu chroot on my HP Touchpad, an ARM-based tablet. What is known is that Banshee has some problems running on Texas Instruments OMAP4 processors the target ARM platform for Canonical s ARM work. None of the Banshee upstream developers, Mono upstream developers, or Mono Ubuntu team has ever been able to reproduce the cited problems, since problems specific to an exact ARM chip are impossible to reproduce without the requisite hardware and none of us owns an ARM system matching Canonical s target. That Banshee is still a GTK+2 app is true. A port to GTK+3 is almost complete, but blocking on a single technical bug deep within GTK# s guts, which could be fixed by someone with sufficient knowledge of GTK+ semantics. Nobody with the required GTK+ knowledge has stepped forward with a fix at this point in time. As for the final point, that Banshee is not well maintained, this seems like a directed personal insult against the active and responsive Banshee maintainer, Chow Loong Jin, and upstream bug triager David Nielsen, in addition to the immeasurable hours contributed free of charge for the benefit of Ubuntu users by various other members of related Mono app and library teams, including myself. I need to stress at this point that my annoyance with this decision has nothing to do with the actual app changes. Keeping Tomboy and gbrainy, at a cost of about 25 meg of unsquashed disk space, is a hard argument to make compared with those two plus Banshee for 40 meg. Dropping gbrainy and Tomboy, and switching to Rhythmbox, will save about 30 meg of unsquashed space, all told.I m unconvinced that Rhythmbox is a technically superior app to Banshee several features which were gained by the first app swap will be lost again but that s another long tedious argument to be had. No, what has me deeply angered is the shambolic way the changes were made and announced. Significant accommodations were made by Banshee upstream in order to make life easier for Canonical to integrate Banshee into their OS. For one thing, that s why the Ubuntu One Music Store support is a core Banshee feature, not part of the third-party community extensions package. If Banshee was being considered for replacement due to unresolved technical issues, then perhaps it would have been polite to, I don t know, inform upstream that it was on the cards? Or, if Canonical felt that problems specific to their own itches required scratching, then is it completely beyond the realm of possibility to imagine they might have spent developer resources on bug fixing their OS and sending those fixes upstream? Or even and call me crazy providing access for upstream to specialized hardware such as a $174 Pandaboard to empower upstream to isolate and fix unreproducible bugs specific to Canonical s target hardware? And here s where it gets more astonishing for me Canonical paid money to ship one of the community-based packagers responsible for the stack, Iain Lane, to Orlando for UDS, and didn t think it was worth bothering to perhaps inform him hey, the stuff you work on is in danger of being axed from the default install, maybe you should go to this session . So I m not cross that the stuff I work on has been removed from the default install. I intend to continue working on it as I have for the last 4 years, through my work in Debian. No, why I m cross that I heard about it from fucking Boycott Novell. Regardless of your opinions regarding Banshee or its stack, if you read the above and don t see it as an abysmal failure of community engagement by a company whose community manager wrote a book on the damn topic, then there s something seriously wrong with your understanding of how community labour should be seen as a resource. Maybe someone at Canonical should try reading Jono s book. It s not a first-time offence, and this mail from a PiTiVi developer regarding changes in 11.10 makes for useful further reading. [edit] There is some worthwhile discussion going on on the ubuntu-desktop mailing list covering the technical issues surrounding the decision, I would suggest it s a good place for ongoing technical discussion.

It's about time that Rapha l is interviewed in the "People behind Debian" series he initiated on his blog. Indeed, when he interviews people, Rapha l asks about other people they could suggest for next interviews. So, during mine, I suggested him to be a next "victim". As he couldn't interview himself, I volunteered for this. As you'll see below, Rapha l (who's a friend of mine as I'm a friend of his) likes to speak and that shows in the length of his answers :-) but you always know more about Debian when reading his blog posts, books, mails, etc. I personnally think that he is among the best promoters of the project for years and it was a pleasure for me to conduct this interview. My questions are in bold, the rest is by Rapha l. Who are you? Hi, Rapha l Hertzog, I'm a 32 years old French Debian developer who is married and who has a 2-year old son. I'm running my own company (Freexian) since 2005, I started it 3 years after the end of my computer science studies. I'm also a very proud author of the Cahier de l'Admin Debian, a French book about Debian. You often wrote about your attempts to make your living partly, if not completely, out of your Debian work. Can you describe the way you're trying to do this? My first try has been with Freexian. I always advertised this company as being specialized in Debian GNU/Linux. While Freexian is successful enough to provide me a decent income, I'm not really satisfied with the result because very few of my contracts are about improving Debian. I use Debian daily for the benefit of my customers, writing new customer specific (embedded) software, deploying a service on Debian servers, etc. But except for the occasional bugfix, all this work does not improve Debian (the only exception has been the dpkg multiarch implementation work sponsored by Linaro). The positive side is that I don't need to fill my entire schedule to earn enough money to live. So I'm regularly taking some days off work to be able to contribute to Debian. This is a freedom that I enjoy... My French book has also been a bestseller and depending on the years the royalties represented between 1 and 2 months of supplementary time that I can spend on Debian (that is between 2000 and 4000 EUR of income). Now since last year, I decided to actively work towards my goal of making a living out of my Debian work. I want to build on what has been most successful for me up to now, that is my book. My strategy has been to build an audience around my blog: with a direct contact with my readers I have the opportunity to sell e-books, and without any intermediary taking the biggest part of the price, I don't need a very large audience to be successful. I have also been experiencing micro-donations with Flattr, people who are enjoying my articles on my blog can use it to give a few cents for each article they find useful. With a large enough userbase, this could fund free documentation and would avoid the need for commercial e-books but we're not there currently and I don't know if it will ever reach the critical mass. Last but not least, I'm soliciting donations for my Debian work on the sidebar of my blog, and I have the chance to a have a few (regular) donators. You're a proud father since last year. How do you manage your commitment to the project with your family life? There are few things that I put above Debian in my life, but my family certainly is. I try to handle most of my Debian duties during work hours so that I can spend time with my family on evenings and during week-ends but in truth I never really disconnect from Debian. It happens quite often that I say to my wife I'll come in a few minutes, let me finish this and then I end up responding to a Debian mail, or an IRC query and take 30 minutes instead of the 5 expected ones. I try hard to avoid this but it's difficult. Luckily for me, my wife is very supportive of my Debian involvement and knows me well... By the way my wife is using Debian on her computer, and my son has already played with DoudouLinux (a Debian derivative!). Have you already been accused of self-promotion in your writings? If that would ever happen, what would you answer to that? Yes, more than once. I am proud of what I do for Debian, I enjoy sharing the result of my work. Because of this, some people believe that I'm selfish and egocentric. And this has somewhat increased since I have been soliciting donations: for me it's important to be transparent towards donators so that they see what I really do for Debian. But some people have the feeling that I'm getting undeserved attention and that I bring everything towards my own person. On the other side, as an author, I'm a public figure who is definitely seeking some attention... I don't have any miraculous answer, we are a large and diverse community, it's next to impossible to please everybody. I listen to all the concerns that people bring forward, I take them into account as much as possible, in particular when I believe they are reasonable/well justified, or when they come from people that I highly respect. But sometimes I have to plainly ignore them too... in particular when they are trying to impose their own political view on a topic that's not directly related to the only value that we all share: the social contract. Contributing to Debian is a challenge, we all have to make efforts to put aside our differences and to concentrate on the work that brings us closer to the best free software operating system ever built. You recently launched a campaign to free out the soon-to-be-published "Debian Administrator Handbook", an English version of your well-known book about Debian in French. Can you tell us more about this project? My French book has been very successful at helping people to get started with Debian, and like I already explained, it was also effective to fund a part of my Debian work. So I wanted to make it available world-wide by publishing an English translation of it. I tried to find an English-speaking editor willing to take on the challenge but I found none interested. Not put off by a setback, Roland (my co-author) and I decided to negotiate with our French editor Eyrolles to recuperate the necessary rights to translate the book into English. Handling everything ourselves represents a lot of work, but it also means that we have the freedom required to decide of the license of the resulting book. We would love to see it under a license compatible with the Debian Free Software Guidelines. But at the same time we firmly believe that we deserve a reasonable monetary compensation for the work on the book, so we conditioned its liberation to a predefined amount of money (25 K ) in what we call the "liberation fund". And since we wanted to be sure that we would have the required means to complete the translation, we used a crowfunding platform to seek support of people interested by the book. With such a platform you're only debited if the minimal requested amount is reached. Anyone can participate, pre-order the book and/or put some money in the liberation fund. As of today, we already reached the minimal funding goal (15 K ) so the book translation will happen. But the liberation target has not yet been reached so we don't know yet if the book will be free from the start... you can follow the progress right on the fundraising page or on the website dedicated to the book. PS: If you want to contribute to this project and also make a donation to Debian at the same time, you should check out this page. You're one of the main developers of dpkg, a critical tool for Debian systems. Can you tell us more about the current development challenges it is facing? What will be the new dpkg features for wheezy? The current challenges are not really technical. dpkg is a relatively mature piece of software and it will continue to work for the foreseeable future without needing much maintenance work. The real challenge is trying to setup a healthy developement community around it so that we can keep tackling new interesting problems (there are many listed in the roadmap and in the 225 wishlist bugs). There is a real problem of leadership and communication in the current team. We used to be three, and we're only two nowadays. Guillem is the legitimate leader since he's involved in dpkg's developement since early 2006 while I joined only in late 2007. But in the last 4 years, we did not manage to recruit anyone else on the team. Some persons tried to contribute significant new features (like Sean Finney with a rework of the way we handle configuration files) but they gave up frustrated after a while because we did not manage to review their work (and discuss the design) in any reasonable timeframe. Another famous case is Ian Jackson with his trigger work. His work got merged, but so late that in the mean time he blew up while trying to hijack the maintenance of dpkg. For a long time I was concentrating my work on the Perl part of dpkg (aka dpkg-dev mainly), so I did not feel qualified to review and merge work related to the C part and I was just a worried observator of this situation. I tried to improve it by setting up some basic review infrastructure, it should have brought some lisibility to the status of each change left to be reviewed... but it has not been used and it changed nothing. Over the years, I became much more interested in the C part. My first big contribution in C has been the rewrite of update-alternatives (from Perl to C). I made other small changes in between, but at the start of this year I had this great opportunity to work on the multiarch implementation (FYI, multiarch is the possibility to mix packages from several architectures on a single system). This really forced me to jump into the C codebase and learn a lot about how dpkg is implemented. Thanks to this I have been able to tackle other small projects (like the improved triggers). This would be all great if my multiarch work was already merged, but it's not. It's a large work, I do not mind waiting a bit in particular since Guillem is a highly skilled C programmer. His sharp analysis of new designs are invaluable, when he reviews code he always finds something to improve. I learnt a lot just by reviewing the code he wrote over the years. That said I have been waiting since April without almost no updates from him. With the release team asking us to hurry up, the situation is getting somewhat strained as I really want to see multiarch in Wheezy and I do not really want to short-circuit Guillem. Hum, I may have drifted a bit from your original question... what great new features can people expect? Well multiarch is supposed to be the big new feature, apart from that there aren't many things that matter to the end users. But there are already quite a few changes that are of interest to package maintainers (like hardened build flags, source package improvements, improved triggers, ). What's the biggest problem of Debian? Manicheism and a tendency to quickly polarize the discussions. In reality, there are very few situations where everything is all good or all bad. Ever since I have read The 7 Habits of Highly Effective People I try hard to put into practice the habits of interdependence . Instead of having only my point of view in mind, I try to understand the motivations from the other party ( Seek First to Understand, Then to be Understood ) in order to be able to put forward solutions acceptable to both parties ( Think Win-Win ). I highly recommend this book to anyone. And I invite everybody to at least try to follow those simple advices. Is there someone in Debian you admire for their contributions? There are many and I can't give an exhaustive list... here are some that I would like to highlight (in no particular order):

• Niels Thykier for the work he puts into Lintian, and his recent work on a britney test-suite (the software that creates testing out of unstable);
• Joachim Breitner for his britney reimplementation using a SAT solver;
• Adam D. Barrat for his work on britney2;
• All the release team members who take care of an endless stream of transitions;
• Christoph Berg for his continuous work over the years on various QA infrastructure (DDPO, Mole, );
• Enrico Zini for the way he helped reform the New Member process without any big disruption;
• Russ Allbery for his Debian Policy work and for being a model in terms of how we should interact on Debian mailing lists;
• Stefano Zacchiroli for being the most active leader that I have ever seen, and for the way he tries to steer important discussions to a constructive conclusion.
• etc.

Most of those people are working on improving Debian's infrastructure so that we can all be more effective and do an even better work. This kind of work is not always very visible but it's crucial to Debian's future. Thank you to Rapha l for the time spent answering my questions. I hope you enjoyed reading his answers as I did. And, anyway, it was fun to just play the game "the other way".

[Latest version of these instructions can be found at the SFML Wiki] CMake allows your project to be built in various environments, including command-line make, Code::Blocks project files, Eclipse project files, etc. It's used in SFML 2.0. In this tutorial we'll write a simple CMake configuration file with centralized version numbering, and see how to integrate SFML in it. The source files First, create a cmake_modules directory and copy FindSFML.cmake in it. FindXXXX is automatically searched by CMake's find_package command. Then create a main.cpp, for instance:

#include "config.h"
#include <iostream>
#include <SFML/Window.hpp>
using namespace std;
int main(int argc, char* argv[])  
  cout << "Version " << myproject_VERSION_MAJOR << "." << myproject_VERSION_MINOR << endl;
  sf::Window screen(sf::VideoMode(800, 600), "myproject");
  bool running = true;
  while (running)  
    screen.Display();
   
 

We use a config.h file that is built by CMake, let's also create a config.h.in file:

#define myproject_VERSION_MAJOR @myproject_VERSION_MAJOR@
#define myproject_VERSION_MINOR @myproject_VERSION_MINOR@

And place your project license (such as the GNU GPL) in a file named COPYING. CMake configuration Let's describe our project configuration in the CMakeLists.txt file:

cmake_minimum_required(VERSION 2.6)
project(myproject)
# Set version information in a config.h file
set(myproject_VERSION_MAJOR 1)
set(myproject_VERSION_MINOR 0)
configure_file(
  "$ PROJECT_SOURCE_DIR /config.h.in"
  "$ PROJECT_BINARY_DIR /config.h"
  )
include_directories("$ PROJECT_BINARY_DIR ")
# Define sources and executable
set(EXECUTABLE_NAME "myproject")
add_executable($ EXECUTABLE_NAME  main.cpp)
# Detect and add SFML
set(CMAKE_MODULE_PATH "$ CMAKE_SOURCE_DIR /cmake_modules" $ CMAKE_MODULE_PATH )
find_package(SFML 1.6 REQUIRED system window graphics network audio)
target_link_libraries($ EXECUTABLE_NAME  $ SFML_LIBRARIES )
# Install target
install(TARGETS $ EXECUTABLE_NAME  DESTINATION bin)
# CPack packaging
include(InstallRequiredSystemLibraries)
set(CPACK_RESOURCE_FILE_LICENSE "$ CMAKE_SOURCE_DIR /COPYING")
set(CPACK_PACKAGE_VERSION_MAJOR "$ myproject_VERSION_MAJOR ")
set(CPACK_PACKAGE_VERSION_MINOR "$ myproject_VERSION_MINOR ")
include(CPack)

The interesting part is:

# Detect and add SFML
set(CMAKE_MODULE_PATH "$ CMAKE_SOURCE_DIR /cmake_modules" $ CMAKE_MODULE_PATH )
find_package(SFML 1.6 REQUIRED system window graphics network audio)
target_link_libraries($ EXECUTABLE_NAME  $ SFML_LIBRARIES )

• First we specify where we stored the FindSFML.cmake module.
• Then we request CMake to look for it in the system, and search for the specified modules (here I specified them all).
• Last, we tell CMake to link our executable with the SFML libraries that it just found.

Compilation To build with Make and the GCC compiler on the command-line:

cd build/  # a separate directory so we can easily remove all the CMake work files
cmake ..  # generate Makefile's
make

To create Code::Blocks project files:

cmake .. -G "CodeBlocks - Unix Makefiles"

and open project.cbp with Code::Blocks. Installation CMake supports the classic:

make install

It also supports DESTDIR, useful in packaging:

make install DESTDIR= pwd /myworkdir

You can also define CMAKE_INSTALL_PREFIX when invoking cmake to change the default install path (/usr/local under Unix). DESTDIR would still override this setting. Packaging You then can use cpack to make a project release:

# Binary package:
cpack -C CPackConfig.cmake
# Source package:
cpack -C CPackSourceConfig.cmake

You will get a nice myproject-1.0.tar.gz, among others. Further information

• CMake has built-in help, for instance:

$ cmake --help-variable CMAKE_SOURCE_DIR
cmake version 2.8.5
  CMAKE_SOURCE_DIR
       The path to the top level of the source tree.
       This is the full path to the top level of the current CMake source
       tree.  For an in-source build, this would be the same as
       CMAKE_BINARY_DIR.

• Reference for v2.8
• CMake Tutorial

Some days ago, a hacker group, THC, released a denial of service tool for SSL web servers. As stated in its description, the problem is not really new: a complete SSL handshake implies costly cryptographic computations. There are two different aspects in the presented attack:

• The computation cost of an handshake is more important on the server side than on the client side. The advisory explains that a server will require 15 times the processing power of a client. This means a single average workstation could challenge a multi-core high-end server.
• The use of SSL renegotiation allows to trigger hundreds of handshakes in the same TCP connection. Even a client behind a DSL connection can therefore bomb a server with a lot of renegotiation requests.

Mitigation techniques There is no definitive solution to this attack but there exists some workarounds. Since the DoS tool from THC relies heavily on renegotiation, the most obvious one is to disable this mechanism on the server side but we will explore other possibilities.

Disabling SSL renegotiation Tackling the second problem seems easy: just disable SSL renegotiation. It is hardly needed: a server can trigger a renegotiation to ask a client to present a certificate but a client usually does not have any reason to trigger one. Because of a past vulnerability in SSL renegotiation, recent version of Apache and nginx just forbid it, even when the non-vulnerable version is available. openssl s_client can be used to test if SSL renegotiation is really disabled. Sending R on an empty line trigger renegotiation. Here is an example where renegotiation is disabled (despite being advertised as supported):

$ openssl s_client -connect www.luffy.cx:443 -tls1
[...]
New, TLSv1/SSLv3, Cipher is DHE-RSA-AES256-SHA
Server public key is 2048 bit
Secure Renegotiation IS supported
Compression: zlib compression
Expansion: zlib compression
[...]
R
RENEGOTIATING
140675659794088:error:1409E0E5:SSL routines:SSL3_WRITE_BYTES:ssl handshake failure:s3_pkt.c:591:

Disabling renegotation is not trivial with OpenSSL. As an example, I have pushed a patch to disable renegotiation in stud, the scalable TLS unwrapping daemon.

Rate limiting SSL handshakes Disabling SSL renegotiation on the client side is not always possible. For example, your web server may be too old to propose such an option. Since those renegotiations should not happen often, a workaround is to limit them. When the flaw was first advertised, F5 Networks provided a way to configure such a limitation with an iRule on their load-balancers. We can do something similar with just Netfilter. We can spot most TCP packets triggering such a renegotiation by looking for encrypted TLS handshake record. They may happen in a regular handshake but in this case, they usually are not at the beginning of the TCP payload. There is no field saying if a TLS record is encrypted or not (TLS is stateful for this purpose). Therefore, we have to use some heuristics. If the handshake type is unknown, we assume that this is an encrypted record. Moreover, renegotiation requests are usually encapsulated in a TCP packet flagged with push .

# Access to TCP payload (if not fragmented)
payload="0 >> 22 & 0x3C @ 12 >> 26 & 0x3C @"
iptables -A LIMIT_RENEGOCIATION \
    -p tcp --dport 443 \
    --tcp-flags SYN,FIN,RST,PSH PSH \
    -m u32 \
    --u32 "$payload 0 >> 8 = 0x160300:0x160303 && $payload 2 & 0xFF = 3:10,17:19,21:255" \
    -m hashlimit \
    --hashlimit-above 5/minute --hashlimit-burst 3 \
    --hashlimit-mode srcip --hashlimit-name ssl-reneg \
    -j DROP

The use of u32 match is a bit difficult to read. The manual page gives some insightful examples. $payload allows to seek for the TCP payload. It only works if there is no fragmentation. Then, we check if we have a handshake (0x16) and if we recognise TLS version (0x0300, 0x0301, 0x0302 or 0x0303). At least, we check if the handshake type is not a known value. There is a risk of false positives but since we use hashlimit, we should be safe. This is not a bullet proof solution: TCP fragmentation would allow an attacker to evade detection. Another equivalent solution would be to use CONNMARK to record the fact the initial handshake has been done and forbid any subsequent handshakes. If you happen to disable SSL renegociation, you can still use some Netfilter rule to limit the number of SSL handshakes by limiting the number of TCP connections from one IP:

iptables -A LIMIT_SSL \
    -p tcp --dport 443 \
    --syn -m state --state NEW \
    -m hashlimit \
    --hashlimit-above 120/minute --hashlimit-burst 20 \
    --hashlimit-mode srcip --hashlimit-name ssl-conn \
    -j DROP

Your servers will still be vulnerable to a large botnet but if there is only a handful of source IP, this rule will work just fine¹. I have made all those solutions available in a single file.

Increasing server-side power processing SSL can easily be scaled up and out. Since SSL performance increases linearly with the number of cores, scaling up can be done by throwing in more CPU or more cores per CPU. Adding expensive SSL accelerators would also do the trick. Scaling out is also relatively easy but you should care about SSL session resume.

Putting more work on the client side In their presentation of the denial of service tool, THC explains:

Establishing a secure SSL connection requires 15 more processing power on the server than on the client.

I don t know where this figure comes from. To check it, I built a small tool to measure CPU time of a client and a server doing 1000 handshakes with various parameters (cipher suites and key sizes). The results are summarized on the following plot: For example, with 2048bit RSA certificates and a cipher suite like AES256-SHA, the server needs 6 times more CPU power than the client. However, if we use DHE-RSA-AES256-SHA instead, the server needs 34% less CPU power. The most efficient cipher suite from the server point of view seems to be something like DHE-DSS-AES256-SHA where the server needs half the power of the client. However, you can t really uses those shiny cipher suites:

1. Some browsers do not support them: they are limited to RSA cipher suites².
2. Using them will increase your regular load a lot. Your servers may collapse with just legitimate traffic.
3. They are expensive for some mobile clients: they need more memory, more processing power and will drain battery faster.

Let s dig a bit more on why the server needs more computational power in the case of RSA. Here is a SSL handshake when using a cipher suite like AES256-SHA: When sending the Client Key Exchange message, the client will encrypt TLS version and 46 random bytes with the public key of the certificate sent by the server in its Certificate message. The server will have to decrypt this message with her private key. Those are the two most expensive operations in the handshake. Encryption and decryption are done with RSA (because of the selected cipher suite). To understand why decryption is more expensive than encryption, let me explain how RSA works. First, the server needs a public and a private key. Here are the main steps to generate them:

1. Pick two random distinct prime numbers p and q , each roughly the same size.
2. Compute n=pq . It is the modulus.
3. Compute \varphi(n)=(p-1)(q-1) .
4. Choose an integer e such that 1<e<\varphi(n) and \gcd(\varphi(n),e) = 1 (i.e. e and \varphi(n) are coprime). It is the public exponent.
5. Compute d=e^ -1 \mod\varphi(n) . It is the private key exponent.

The public key is (n,e) while the private key is (n,d) . A message to be encrypted is first turned into an integer m<n (with some appropriate padding). It is then encrypted to a ciphered message c with the public key and should only be decrypted with the private key:

• c=m^e\mod n (encryption)
• m=c^d\mod n (decryption)

So, why is decryption more expensive? In fact, the key pair is not really generated like I said above. Usually, e is a small fixed prime number with a lot of 0, like 17 (0x11) or 65537 (0x10001) and p and q are choosen such that \varphi(n) is coprime with e . This allows encryption to be fast using exponentiation by squaring. On the other hand, its inverse d is a big number with no special property and therefore, exponentiation is more costly and slow. Instead of computing d from e , it is possible to choose d and compute e . We could choose d to be small and coprime with \varphi(n) and then compute e=d^ -1 \mod\varphi(n) and get blazingly fast decryption. Unfortunately, there are two problems with this:

• Most SSL implementation expects e to be a 32bit integer.
• If d is too small (less than one-quarter as many bits as the modulus n ), it can be computed efficiently from the public key.

Therefore, we cannot use a small private exponent. The best we can do is to choose the public exponent to be e =4294967291 (the biggest prime 32bit number and it contains only one 0). However, there is no change as you can see on our comparative plot. To summarize, no real solution here. You need to allow RSA cipher suites and there is no way to improve the computational ratio between the server and the client with such a cipher suite.

Things get worse Shortly after the release the denial of service tool, Eric Rescorla³ published a good analysis on the impact of such a tool. He asks himself about the efficiency to use renegotiation for such an attack:

What you should be asking at this point is whether a computational DoS attack based on renegotiation is any better for the attacker than a computational DoS attack based on multiple connections. The way we measure this is by the ratio of the work the attacker has to do to the work that the server has to do. I ve never seen any actual measurements here (and the THC guys don t present any), but some back of the envelope calculations suggest that the difference is small. If I want to mount the old, multiple connection attack, I need to incur the following costs:

1. Do the TCP handshake (3 packets)
2. Send the SSL/TLS ClientHello (1 packet). This can be a canned message.
3. Send the SSL/TLS ClientKeyExchange, ChangeCipherSpec, Finished messages (1 packet). These can also be canned.

Note that I don t need to parse any SSL/TLS messages from the server, and I don t need to do any cryptography. I m just going to send the server junk anyway, so I can (for instance) send the same bogus ClientKeyExchange and Finished every time. The server can t find out that they are bogus until it s done the expensive part. So, roughly speaking, this attack consists of sending a bunch of canned packets in order to force the server to do one RSA decryption.

I have written a quick proof of concept of such a tool. To avoid any abuse, it will only work if the server supports NULL-MD5 cipher suite. No sane server in the wild will support such a cipher. You need to configure your web server to support it before using this tool. While Eric explains that there is no need to parse any SSL/TLS messages, I have found that if the key exchange message is sent before the server send the answer, the connection will be aborted. Therefore, I quickly parse the server s answer to check if I can continue. Eric also says a bogus key exchange message can be sent since the server will have to decrypt it before discovering it is bogus. I have choosen to build a valid key exchange message during the first handshake (using the certificate presented by the server) and replay it on subsequent handshakes because I think the server may dismiss the message before the computation is complete (for example, if the size does not match the size of the certificate). With such a tool and 2048bit RSA certificate, a server is using 100 times more processing power than the client. Unfortunately, this means that most solutions, except rate limiting, exposed on this page may just be ineffective.

---

1. However, since this rule relies on source IP to identify the attacker, the risk of false positive is real. You can slow down legitimate proxies, networks NATed behind a single IP, mobile users sharing an IP address or people behind a CGN.
2. Cipher suites supported by all browsers are RC4-MD5, RC4-SHA and 3DES-SHA. Support for DHE-DSS-AES256-SHA requires TLS 1.2 (not supported by any browser).
3. Eric is one of the author of several RFC related to TLS. He knows his stuff.

a bit late & short (I was travelling the last days) but here it is: the recent update of my RC bug acitivities:

• #625430 vrb: "vrb: ftbfs with gcc-4.6 -Werror"
  add patch from Dmitri Bachtin, upload to DELAYED/2, then rescheduled to 0-day with maintainer's permission
• #625433 simulavr: "simulavr: ftbfs with gcc-4.6 -Werror"
  add patch from Ubuntu / Daniel T Chen, upload to DELAYED/2
• #628256 src:boinc-app-milkyway: "boinc-app-milkyway: FTBFS: g++: error: unrecognized option '--export_dynamic'"
  add patch from Ubuntu / Daniel T Chen, upload to DELAYED/2
• #628300 src:arrayprobe: "arrayprobe: FTBFS: Configuration file ".config" not found!"
  add patch from Ubuntu / Matthias Klose, upload to DELAYED/2
• #628318 src:kcheckgmail: "kcheckgmail: FTBFS: index.docbook:6: warning: failed to load external entity "dtd/kdex.dtd""
  add patch from Ubuntu / Michael Bienia, do a QA upload
• #628348 src:nn: "nn: FTBFS: ymakefile:12: *** commands commence before first target. Stop."
  add patch from Ubuntu / Andreas Moog, upload to DELAYED/2
• #629658 src:crossroads: "crossroads: FTBFS: start.cc:22: undefined reference to pthread_create'"
  add patch from Ubuntu / Andreas Moog, upload to DELAYED/2