tahoe-lafs/docs/known_issues.txt

= Known Issues =

Below is a list of known issues in recent releases of Tahoe-LAFS, and how to
manage them.  The current version of this file can be found at

http://allmydata.org/source/tahoe/trunk/docs/known_issues.txt

Older versions of this document describing issues in older versions of
Tahoe-LAFS can be found at

http://allmydata.org/source/tahoe/trunk/docs/historical/historical_known_issues.txt

== issues in Tahoe v1.3.0, released 2009-02-13 ==


=== potential unauthorized access by JavaScript in unrelated files ===

If you view a file stored in Tahoe through a web user interface,
JavaScript embedded in that file might be able to access other files or
directories stored in Tahoe which you view through the same web user
interface.  Such a script would be able to send the contents of those
other files or directories to the author of the script, and if you have
the ability to modify the contents of those files or directories, then
that script could modify or delete those files or directories.

==== how to manage it ====

For future versions of Tahoe, we are considering ways to close off
this leakage of authority while preserving ease of use -- the
discussion of this issue is ticket #615.

For the present, either do not view files stored in Tahoe through a web
user interface, or turn off JavaScript in your web browser before doing
so, or limit your viewing to files which you know don't contain
malicious JavaScript.


=== potential disclosure of file through embedded
hyperlinks or JavaScript in that file ===

If there is a file stored on a Tahoe storage grid, and that file gets
downloaded and displayed in a web browser, then JavaScript or
hyperlinks within that file can leak the capability to that file to a
third party, which means that third party gets access to the file.

If there is JavaScript in the file, then it could deliberately leak
the capability to the file out to some remote listener.

If there are hyperlinks in the file, and they get followed, then
whichever server they point to receives the capability to the
file. Note that IMG tags are typically followed automatically by web
browsers, so being careful which hyperlinks you click on is not
sufficient to prevent this from happening.

==== how to manage it ====

For future versions of Tahoe, we are considering ways to close off
this leakage of authority while preserving ease of use -- the
discussion of this issue is ticket #127.

For the present, a good work-around is that if you want to store and
view a file on Tahoe and you want that file to remain private, then
remove from that file any hyperlinks pointing to other people's
servers and remove any JavaScript unless you are sure that the
JavaScript is not written to maliciously leak access.


=== command-line arguments are leaked to other local users ===

Remember that command-line arguments are visible to other users
(through the 'ps' command, or the windows Process Explorer tool), so
if you are using a Tahoe node on a shared host, other users on that
host will be able to see (and capture) any directory caps that you set
up with the "tahoe add-alias" command.

==== how to manage it ====

Bypass add-alias and edit the NODEDIR/private/aliases file directly,
by adding a line like this:

fun: URI:DIR2:ovjy4yhylqlfoqg2vcze36dhde:4d4f47qko2xm5g7osgo2yyidi5m4muyo2vjjy53q4vjju2u55mfa

By entering the dircap through the editor, the command-line arguments are
bypassed, and other users will not be able to see them. Once you've added the
alias, no other secrets are passed through the command line, so this
vulnerability becomes less significant: they can still see your filenames and
other arguments you type there, but not the caps that Tahoe uses to permit
access to your files and directories.  In Tahoe v1.3.0, there is a new
"tahoe create-aliase" command that does this for you.