Forum: Ruby Samizdat 0.6.2: Security, Plugins, Flowplayer

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2f9ac68b6f4cb81ec8c9ea2219ce4059?d=identicon&s=25 Dmitry Borodaenko (Guest)
on 2009-02-12 15:00
(Received via mailing list)
Dedication

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
cooperation.

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:

[0]
http://samizdat.nongnu.org/release-notes/sanitize-...
[1]
http://samizdat.nongnu.org/release-notes/sanitize-...

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].

[2] http://people.debian.org/~angdraug/tidy/

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

  CREATE TABLE Role (member INTEGER REFERENCES Member, role TEXT);
  CREATE INDEX Role_member_idx ON Role (member);
  GRANT INSERT, UPDATE, SELECT ON Role TO samizdat;
  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
line:

  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: http://samizdat.nongnu.org/
Download:
http://savannah.nongnu.org/download/samizdat/samiz...
Debian package: apt-get install samizdat
(http://packages.qa.debian.org/s/samizdat.html)
50b2daf0e7666574579b9edaf8f2b69a?d=identicon&s=25 Pit Capitain (Guest)
on 2009-02-12 20:20
(Received via mailing list)
2009/2/12 Dmitry Borodaenko <angdraug@gmail.com>:
> Samizdat 0.6.2 release is dedicated to the memory of Stanislav Markelov and
> Anastasia Baburova, activists murdered in Moscow on January 19, 2009.
> (...)

Hi Dmitry, nice to read from you again. We once met in Karlsruhe a
couple of years ago, where you talked about Samizdat at EuRuKo. I
always liked your reasoning for the name Samizdat, and now also the
dedication of the new release. Unfortunately I don't have anything to
do with RDF, so can't say more to Samizdat itself.

Regards,
Pit
2f9ac68b6f4cb81ec8c9ea2219ce4059?d=identicon&s=25 Dmitry Borodaenko (Guest)
on 2009-02-12 21:25
(Received via mailing list)
On Thu, Feb 12, 2009 at 9:18 PM, Pit Capitain <pit.capitain@gmail.com>
wrote:
> Hi Dmitry, nice to read from you again. We once met in Karlsruhe a
> couple of years ago, where you talked about Samizdat at EuRuKo. I
> always liked your reasoning for the name Samizdat, and now also the
> dedication of the new release. Unfortunately I don't have anything to
> do with RDF, so can't say more to Samizdat itself.

Hi Pit!

Thanks for your support, much appreciated! I remember you from Karlsuhe,
too :) It was a nice time, a shame actually that we couldn't establish
EuRuKo as a regular event...

You know, over the last years focus of Samizdat development shifted away
from RDF and more towards open publishing. It still does RDF, and RDF
code has become more advanced (and, by necessity, much more
well-structured), but it has taken a back seat to things that matter in
real world: security, usability, multimedia support, etc. If the
prominent place RDF takes in Samizdat's description scares people off
like that, I should probably rephrase it: Samizdat is no longer an RDF
system that incidentally does open publishing, it's an open publishing
system that happens to have RDF under the hood.

I think that other standalone modules in Samizdat library, while small
and single-purpose, deserve more attention than that scary RDF storage.
For example, the story of the Sync#try_lock bug kind of proves that
Samizdat Cache module is the most advanced Ruby object cache
implementation out there (unless I'm missing something and there is a
way to do thread-safe two-level locking without that API ;)

I'm also quite proud of the Sanitize module: it might be comparatively
slow due to invoking both Tidy and REXML, but it is small and elegant,
making it easy to understand and to keep secure. With tools like that
out there, who would need another HTML parser?

The point is, Samizdat is more than an RDF engine. It has other bells
and whistles that may just as interesting!
2f9ac68b6f4cb81ec8c9ea2219ce4059?d=identicon&s=25 Dmitry Borodaenko (Guest)
on 2009-02-13 11:59
(Received via mailing list)
On Thu, Feb 12, 2009 at 10:24 PM, Dmitry Borodaenko <angdraug@gmail.com>
wrote:
> a shame actually that we couldn't establish EuRuKo as a regular event...

Heh, just noticed I'm a bit wrong about this, looks like it did pick up,
after
all! Now there's my chance for a soapbox ;-)
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