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[ANN] Samizdat 0.6.2: Security, Plugins, Flowplayer

From: Dmitry Borodaenko
Subject: [ANN] Samizdat 0.6.2: Security, Plugins, Flowplayer
Date: Thu, 12 Feb 2009 15:54:05 +0200


Samizdat 0.6.2 release is dedicated to the memory of Stanislav Markelov and
Anastasia Baburova, activists murdered in Moscow on January 19, 2009.

What is Samizdat?

Samizdat is a generic RDF-based engine for building collaboration and
open publishing web sites. Samizdat provides users with means to
cooperate and coordinate on all kinds of activities, including media
activism, resource sharing, education and research, advocacy, and so on.
Samizdat intends to promote values of freedom, openness, equality, and

Samizdat library includes four stand-alone modules that can be used
outside the Samizdat engine: Cache (thread-safe time-limited object
cache with flexible replacement policy), Storage (RDF storage over a
relational database), Sanitize (whitelist XSS filter based on HTMLTidy
and REXML), and Antispam (simple wiki spam filter).

What's new in Samizdat 0.6.2?

The most important part of this release is the long list of security
improvements in various parts of Samizdat engine. Password encryption is now as
strong as it gets, HTTPS now gets the emphasis it deserves, cross-site scripting
protection has been tightened, and in general the engine is even more paranoid
about user-submitted data than before.

End users will be most interested in the integration with Flowplayer free Flash
video player and the thumbnailing capabilities of the new image plugin. Both
features are enabled by the new plugin mechanism, which, in addition to handling
different content types, allows to add fancy member profile parameters and
alternative access control schemes.

Due to the number of security improvements in this release, it is highly
recommended that all Samizdat installations update to this version. If you are
not able to update your installation immediately, you should apply the following
patches (applicable to vanilla Samizdat 0.6.1) at the first opportunity:


Changes in more detail:

- cross-site scripting fixes: several cases of unsanitized user-submitted HTML
  strings are fixed in this release; these vulnerabilities allowed attackers to
  perform cross-site scripting attacks by publishing specially crafted messages
  or user names (CVE-2009-0359)

- passwords: over the past several years, multiple attacks on the MD5 hash
  function were demonstrated, making this algorithm less than optimal for
  password encryption; while Samizdat 0.6.2 still supports old MD5 passwords,
  all new passwords will use salted SHA-512; users of Samizdat sites are advised
  to update their passwords to take advantage of stronger password encryption

- HTTPS logins: it is now possible to ensure that all authenticated access to a
  Samizdat site goes only over an encrypted HTTPS connection; comments in the
  https section of config.yaml explain how to make this work

- plugins: the new plugin system allows to augment and customize various parts
  of Samizdat engine, including content rendering, member profile parameters,
  and access control

- image thumbnails: new image plugin automatically generates and uses reduced
  versions of uploaded images with help of the RMagick library

- Flowplayer: flowplayer plugin integrates this free Flash video player into
  Samizdat pages, allowing to display FLV and MP4/H.264 files inline in addition
  to the usual download link; as of this release, Flowplayer doesn't reliably
  work with free Flash plugins Gnash and SWFdec, more collaboration between
  these projects is needed to implement a fully free Flash video stack

- GPL3: Samizdat license has been upgraded to the latest version of GPL and now
  reads: "You can distribute/modify this program under the terms of the GNU
  General Public License version 3 or later."

- Mahoro: instead of relying on inconsistent and untrustworthy content type
  headers supplied by web browser, Samizdat now uses Mahoro bindings to libmagic
  library to determine real content type of the uploaded files

- Sanitize: due to incompatibility of Tidy/DL bindings with the latest Ruby 1.8
  releases, Sanitize now prefers to invoke tidy binary through a pipe instead of
  linking to a shared library; more Tidy errors are now handled and reported
  back to the user, single quote special character is now escaped as ' for
  compatibility with browsers that don't support XHTML 1.0 character entities
  (e.g. Internet Explorer)

- member profile: member settings page is split into account, profile, and
  settings pages; settings page controls UI preferences available both to
  members and guests; profile page allows to edit public information about a
  member, such as full name (which is now optional) or occupation (enabled by
  the occupation profile plugin); account parameters such as password and email
  are edited on the account page

- new translations: Japanese translation has been reviewed and corrected by a
  native speaker and is now enabled by default, bringing the count of supported
  languages up to 10

- documentation: several key aspects of Samizdat architecture are explained in
  new Dia diagrams and the LVEE'2008 presentation slides

- other: exported RSS feeds now include item descriptions, tainted data handling
  is now more robust, more bugfixes and UI improvements

How do I upgrade from Samizdat 0.6.1?

First of all, make sure tidy binary (and not just libtidy shared library) is
installed on your system. By default, sanitize.rb checks for /usr/bin/tidy or
/usr/local/bin/tidy. On Debian 5.0/lenny or later, run `apt-get install tidy`.
Debian 4.0/etch has an old Tidy version that doesn't support some of the options
used in Samizdat 0.6.2, so you may need to install the backported Tidy
package [2].


Since moderator list is now stored in database, you need to move your list of
moderators from your yaml config to the database:

  CREATE INDEX Role_member_idx ON Role (member);
  INSERT INTO Role (member, role) SELECT id, 'moderator' FROM Member
  WHERE login IN ('moderator1', 'moderator2', ...);

In the last line, replace ('moderator1', 'moderator2', ...) with your
current moderator list, that can be produced by the following command

  grep moderators /etc/samizdat/sites/*|sed "s/, /', '/g"

You will also need to update your Apache or Lighttpd configuration to
make js/ directory visible via the Web server (see doc/examples/).

Finally, if your access control configuration differs from Samizdat
default (e.g. guests are allowed to post), see defaults.yaml on how
role plugin is configured.

Where to get it?

Project page:
Debian package: apt-get install samizdat

Dmitry Borodaenko

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