[Twisted-Python] announcing Tahoe-LAFS v1.8.3, fixing a security issue

Zooko O'Whielacronx zooko at zooko.com
Wed Sep 14 02:58:16 EDT 2011

Dear Twisted Folks:

We found a vulnerability in Tahoe-LAFS (all versions from v1.3.0 to v1.8.2
inclusive) that might allow an attacker to delete files. This vulnerability
does not enable anyone to read file contents without authorization
(confidentiality), nor to change the contents of a file (integrity). How
exploitable this vulnerability is depends upon some details of how you use
Tahoe-LAFS. If you upgrade your Tahoe-LAFS storage server to v1.8.3, this
fixes the vulnerability.

We've written detailed docs about the issue and how to manage it in
the "Known Issues" document:


I am sorry that we introduced this bug into Tahoe-LAFS and allowed it
to go undetected until now. We aim for a high standard of security and
reliability in Tahoe-LAFS, and we're not satisfied until our users are
safe from threats to their data.

We've been working with the packagers who maintain packages of
Tahoe-LAFS in various operating systems, so if you get your Tahoe-LAFS
through your operating system there may already be a fixed version


Please contact us through the tahoe-dev mailing list if you have
further questions.


Zooko Wilcox-O'Hearn

ANNOUNCING Tahoe, the Least-Authority File System, v1.8.3

The Tahoe-LAFS team announces the immediate availability of version 1.8.3 of
Tahoe-LAFS, an extremely reliable distributed storage system. Get it here:


Tahoe-LAFS is the first distributed storage system to offer
"provider-independent security" — meaning that not even the
operators of your storage servers can read or alter your data
without your consent. Here is the one-page explanation of its
unique security and fault-tolerance properties:


The previous stable release of Tahoe-LAFS was v1.8.2, which was
released January 30, 2011 [1].

v1.8.3 is a stable bugfix release which fixes a security issue. See the file
[2] and known_issues.rst [3] file for details.


With Tahoe-LAFS, you distribute your filesystem across
multiple servers, and even if some of the servers fail or are
taken over by an attacker, the entire filesystem continues to
work correctly, and continues to preserve your privacy and
security. You can easily share specific files and directories
with other people.

In addition to the core storage system itself, volunteers
have built other projects on top of Tahoe-LAFS and have
integrated Tahoe-LAFS with existing systems, including
Windows, JavaScript, iPhone, Android, Hadoop, Flume, Django,
Puppet, bzr, mercurial, perforce, duplicity, TiddlyWiki, and
more. See the Related Projects page on the wiki [4].

We believe that strong cryptography, Free and Open Source
Software, erasure coding, and principled engineering practices
make Tahoe-LAFS safer than RAID, removable drive, tape,
on-line backup or cloud storage.

This software is developed under test-driven development, and
there are no known bugs or security flaws which would
compromise confidentiality or data integrity under recommended
use. (For all important issues that we are currently aware of
please see the known_issues.rst file [3].)


This release is compatible with the version 1 series of
Tahoe-LAFS. Clients from this release can write files and
directories in the format used by clients of all versions back
to v1.0 (which was released March 25, 2008). Clients from this
release can read files and directories produced by clients of
all versions since v1.0. Servers from this release can serve
clients of all versions back to v1.0 and clients from this
release can use servers of all versions back to v1.0.

This is the fourteenth release in the version 1 series. This
series of Tahoe-LAFS will be actively supported and maintained
for the forseeable future, and future versions of Tahoe-LAFS
will retain the ability to read and write files compatible
with this series.


You may use this package under the GNU General Public License,
version 2 or, at your option, any later version. See the file
"COPYING.GPL" [5] for the terms of the GNU General Public
License, version 2.

You may use this package under the Transitive Grace Period
Public Licence, version 1 or, at your option, any later
version. (The Transitive Grace Period Public Licence has
requirements similar to the GPL except that it allows you to
delay for up to twelve months after you redistribute a derived
work before releasing the source code of your derived work.)
See the file "COPYING.TGPPL.html" [6] for the terms of the
Transitive Grace Period Public Licence, version 1.

(You may choose to use this package under the terms of either
licence, at your option.)


Tahoe-LAFS works on Linux, Mac OS X, Windows, Cygwin, Solaris,
*BSD, and probably most other systems. Start with
"docs/quickstart.html" [7].


Please join us on the mailing list [8]. Patches are gratefully
accepted -- the RoadMap page [9] shows the next improvements
that we plan to make and CREDITS [10] lists the names of people
who've contributed to the project. The Dev page [11] contains
resources for hackers.


Atlas Networks has contributed several hosted servers for performance
testing. Thank you to Atlas Networks for their generous and public-spirited


If you can find a security flaw in Tahoe-LAFS which is serious
enough that we feel compelled to warn our users and issue a fix,
then we will award you with a customized t-shirts with your
exploit printed on it and add you to the "Hack Tahoe-LAFS Hall
Of Fame" [12].


This is the eighth release of Tahoe-LAFS to be created solely
as a labor of love by volunteers. Thank you very much to the
team of "hackers in the public interest" who make Tahoe-LAFS

Zooko Wilcox-O'Hearn
on behalf of the Tahoe-LAFS team

September 13, 2011
Boulder, Colorado, USA

[1] http://tahoe-lafs.org/trac/tahoe/browser/relnotes.txt?rev=5164
[2] http://tahoe-lafs.org/trac/tahoe-lafs/browser/1.8.3/NEWS?rev=5014
[3] http://tahoe-lafs.org/trac/tahoe/browser/docs/known_issues.rst
[4] http://tahoe-lafs.org/trac/tahoe/wiki/RelatedProjects
[5] http://tahoe-lafs.org/trac/tahoe/browser/COPYING.GPL
[6] http://tahoe-lafs.org/source/tahoe/trunk/COPYING.TGPPL.html
[7] http://tahoe-lafs.org/source/tahoe/trunk/docs/quickstart.html
[8] http://tahoe-lafs.org/cgi-bin/mailman/listinfo/tahoe-dev
[9] http://tahoe-lafs.org/trac/tahoe/roadmap
[10] http://tahoe-lafs.org/trac/tahoe-lafs/browser/1.8.3/CREDITS?rev=5003
[11] http://tahoe-lafs.org/trac/tahoe/wiki/Dev
[12] http://tahoe-lafs.org/hacktahoelafs/

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