Debian LTS Work March/April 2016

The end of April marks the one year anniversary of my Debian LTS contributions.  Unfortunately it also marks the end (for now at least) of my contributions under the Freexian umbrella.  While I think this is important work, I have always struggled to find time to do it between family, my regular Debian and other free software work, and my other consulting work.  I’ve decided to quit pretending I’ve got the time to provide the consistent contribution that Freexian needs for Debian LTS, so this is my final report.

This report covers two months because I was not well at the end of March (nothing serious, but the timing was very poor).  During this time I worked on preparing to start supporting Wheezy LTS and prepared and tested updating clamav from 0.99 to 0.99.1.  Unfortunately, uploading it to Wheezy is blocked on it getting in to Jessie.  In the mean time, upstream released 0.99.2.  Once that is in Jessie, I plan to upload it to Wheezy as well so this effort will not go to waste, it just has to wait a bit.

Computer System Security Policy Debate (Follow-up)

As a follow-up to my recent post on the debate in the US over new encryption restrictions, I thought a short addition might be relevant.  This continues.

There was a recent Congressional hearing on the topic that featured mostly what you would expect.  Police always want access to any possible source of evidence and the tech industry tries to explain that the risks associated with mandates to do so are excessive with grandstanding legislators sprinkled throughout.   What I found interesting (and I use that word with some trepidation as it is still a multi-hour video of a Congressional hearing) is that there was rather less grandstanding and and less absolutism from some parties than I was expecting.

There is overwhelming consensus that these requirements [for exceptional access] are incompatible with good security engineering practice

Dr. Matthew Blaze

The challenge is that political people see everything as a political/policy issue, but this isn’t that kind of issue.  I get particularly frustrated when I read ignorant ramblings like this that dismiss the overwhelming consensus of the people that actually understand what needs to be done as emotional, hysterical obstructionism.  Contrary to what seems to be that author’s point, constructive dialogue and understanding values does nothing to change the technical risks of mandating exceptional access.  Of course the opponents of Feinstein-Burr decry it as technologically illiterate, it is technologically illiterate.

This doesn’t quite rise to the level of that time the Indiana state legislature considered legislating a new value (or in fact multiple values) for the mathematical constant Pi, but it is in the same legislative domain.

Future of secure systems in the US

As a rule, I avoid writing publicly on political topics, but I’m making an exception.

In case you haven’t been following it, the senior Republican and the senior Democrat on the Senate Intelligence Committee recently announced a legislative proposal misleadingly called the Compliance with Court Orders Act of 2016.  The full text of the draft can be found here.  It would effectively ban devices and software in the United States that the manufacturer cannot retrieve data from.  Here is a good analysis of the breadth of the proposal and a good analysis of the bill itself.

While complying with court orders might sound great in theory, in practice this means these devices and software will be insecure by design.  While that’s probably reasonably obvious to most normal readers here, don’t just take my word for it, take Bruce Schneier‘s.

In my opinion, policy makers (and it’s not just in the United States) are suffering from a perception gap about security and how technically hard it is to get right.  It seems to me that they are convinced that technologists could just do security “right” while still allowing some level of extraordinary access for law enforcement if they only wanted to.  We’ve tried this before and the story never seems to end well.  This isn’t a complaint from wide eyed radicals that such extraordinary access is morally wrong or inappropriate.  It’s hard core technologists saying it can’t be done.

I don’t know how to get the message across.  Here’s President Obama, in my opinion, completely missing the point when he equates a desire for security with “fetishizing our phones above every other value.”  Here are some very smart people trying very hard to be reasonable about some mythical middle ground.  As Riana Pfefferkorn’s analysis that I linked in the first paragraph discusses, this middle ground doesn’t exist and all the arm waving in the world by policy makers won’t create it.

Coincidentally, this same week, the White House announced a new “Commission on Enhancing National Cybersecurity“.  Cybersecurity is certainly something we could use more of, unfortunately Congress seems to be heading off in the opposite direction and no one from the executive branch has spoken out against it.

Security and privacy are important to many people.  Given the personal and financial importance of data stored in computers (traditional or mobile), users don’t want criminals to get a hold of it.  Companies know this, which is why both Apple IOS and Google Android both encrypt their local file systems by default now.  If a bill anything like what’s been proposed becomes law, users that care about security are going to go elsewhere.  That may end up being non-US companies’ products or US companies may shift operations to localities more friendly to secure design.  Either way, the US tech sector loses.  A more accurate title would have been Technology Jobs Off-Shoring Act of 2016.

EDIT: Fixed a typo.

 

 

Debian LTS Work February 2016

This was my tenth month as a Freexian sponsored LTS contributor. I was assigned 8 hours for the month of February.

As I did last month, I worked on updating clamav in wheezy and squeeze-lts.  As with previous updates to clamav, we updated it to the new upstream version[1].  As an added complexity, this version bumped soname, so it’s now libclamav7 instead of libclamav6.  This bump necessitated a small transition in jessie/wheezy-proposed-updates and squeeze-lts.

The update for Jessie (included for completeness here) was done early in the month by other pkg-clamav team members.  It and the rebuilt/update libclamav reverse-depends will be included in the next Jessie point release.

For wheezy, I uploaded libclamunrar (which bumped soname as well) and worked with other pkg-clamav team members on getting clamav to build on sparc and preparing a fix for c-icap.  It and the rebuilt/update libclamav reverse-depends will be included in the next Wheezy point release.

As a result of the amount of time it took, the squeeze-lts update landed later than I hoped it would, but it is there.  As documented in DLA 437-1, there are new packages for clamav, libclamunrar, python-clamav, and klamav.  The last squeeze libclamav reverse-depend, dansguardian, took more work, but it too is updated, see DLA 440-1.

 

[1] The primary reason for this is that anti-virus is an arms race.  Unlike other types of packages being stable with only fixes for severe bugs and security issues does not result in a stable capability.  It will regress over time.  In order to keep up, the new version is needed.

Postfix 3.0 woes

Postfix 3.0 recently hit Debian Unstable (and Ubuntu Xenial for those that care about that).  It’s been a bit of a bumpy road, but it seems to mostly be there for new installs.  For package upgrades, there’s still issues.  We hope to have that sorted shortly, but in the meantime, all you should need to do to get an upgraded system working is add or adjust two parameters in your main.cf

shlib_directory=/usr/lib/postfix
daemon_directory=/usr/lib/postfix/sbin

You can either edit the file directly or use postconf:

postconf -e shlib_directory=/usr/lib/postfix
postconf -e daemon_directory=/usr/lib/postfix/sbin

No need to file more bugs and yes, we also know postfix 3.1 was just released.  One thing at a time.

Debian LTS Work January 2016

This was my ninth month as a Freexian sponsored LTS contributor. I was assigned 8 hours for the month of January.

My time this month was spent preparing updates for clamav and the associated libclamunrar for squeeze and wheezy.  For wheezy, I’ve only helped a little, mostly I worked on squeeze.

This update is more complex than usual because with clamav 0.99 upstream bumped soname and so in addition to the normal case of transitions in unstable, we’ve needed transitions for stable, oldstable, and squeeze-lts.  We also try to be careful and maintain higher versions in newer releases, so stable needed to wait for 0.99 in testing, oldstable needed to wait for stable, etc.

Currently 0.99 is in stable proposed updates and I’ve requested that the update for wheezy (oldstable) go forward.  Once that’s done, I’ve got squeeze-lts ready to go.

Python Packaging Build-Depends

As a follow-up to my last post where I discussed common Python packaging related errors, I thought it would be worth to have a separate post on how to decide on build-depends for Python (and Python3) packages.

The python ecosystem has a lot of packages built around supporting multiple versions of python (really python3 now) in parallel.  I’m going to limit this post to packages you might need to build-depend on directly.

Python (2)

Since Jessie (Debian 8), python2.7 has been the only supported python version.  For development of Stretch and backports to Jessie there is no need to worry about multiple python versions.  As a result, several ‘all’ packages are (and will continue to be) equivalent to their non-‘all’ counterparts.  We well continue to provide the ‘all’ packages for backward compatibility, but they aren’t really needed any more.

python (or python-all)

This is the package to build-depend on if your package is pure Python (no C extensions) and does not for some other reason need access to the Python header files (there are a handful of packages this latter caveat applies to, if you don’t know if it applies to your package, it almost certainly doesn’t).

You should also build-depend on dh-python.  It was originally shipped as part of the python package (and there is still an old version provided), but to get the most current code with new bug fixes and features, build-depend on dh-python.

python-dev (or python-all-dev)

If your package contains compiled C or C++ extensions, this package either provides or depends on the packages that provide all the header files you need.

Do not also build-depend on python.  python-dev depends on it and it is just an unneeded redundancy.

python-dbg (or python-all-dbg)

Add this if you build a -dbg package (not needed for -dbgsym).

Other python packages

There is not, AFAICT, any reason to build-dep on any of the other packages provided (e.g. libpython-dev).  It is common to see things like python-all, python, python-dev, libpython-dev in build-depends.  This could be simplified just to python-all-dev since it will pull the rest in.

Python3

Build-depends selection for Python 3 is generally similar, except that we continue to want to be able to support multiple python3 versions (as we currently support python3.4 and python3.5).  There are a few differences:

All or not -all

Python3 transitions are much easier when C extensions are compiled for all supported versions.  In many cases all that’s needed if you use pybuild is to build-depend on python3-all-dev.  While this is preferred, in many cases this would be technically challenging and not worth the trouble.  This is mostly true for python3 based applications.

Python3-all is mostly useful for running test suites against all supported python3 versions.

Transitions

As mentioned in the python section above, build-depends on python3-{all-}dev is generally only needed for compiled C extensions.  For python3 these are also the packages that need to be rebuilt for a transition.  Please avoid -dev build-depends whenever possible for non-compiled packages.  Please keep your packages that do need rebuilding binNMU safe.

Transitions happen in three stages:

  1. A new python3 version is added to supported python3 versions and packages that need rebuilding due to compiled code and that support multiple versions are binNMUed to add support for the new version.
  2. The default python3 is changed to be the new version and packages that only support a single python3 version are rebuilt.
  3. The old python3 version is dropped from supported versions and packages will multiple-version support are binNMUed to remove support for the dropped version.

This may seem complex (OK, it is a bit), but it enables a seamless transition for packages with multi-version support since they always support the default version.  For packages that only support a single version there is an inevitable period when they go uninstallable once the default version has changed and until they can be rebuilt with the new default.

Specific version requirements

Please don’t build-depend against specific python3 versions.  Those don’t show up in the transition tracker.  Use X-Python3-Version (see python policy for details) to specify the version you need.

Summary

Please check your packages and only build-depend on the -dev packages when you need it.  Check for redundancy and remove it.  Try and build for all python3 versions.  Don’t build-depend on specific python3 versions.