[tor-bugs] #5056 [Tor Browser]: User Agent bug related to update to Firefox 10

[Tor Bug Tracker & Wiki]

#5056: User Agent bug related to update to Firefox 10
-------------------------+--------------------------------------------------
 Reporter:  cypherpunks  |          Owner:  mikeperry
     Type:  defect       |         Status:  new      
 Priority:  major        |      Milestone:           
Component:  Tor Browser  |        Version:           
 Keywords:               |         Parent:           
   Points:               |   Actualpoints:           
-------------------------+--------------------------------------------------
Changes (by cypherpunks):

  * priority:  normal => major


Comment:

 Replying to [comment:1 arma]:
 > Should Torbutton in TBB stop messing with your user agent? It does more
 harm than good right now. Or should it learn to regexp the Firefox user
 agent so we can claim we're always on Windows but using whichever version
 of Firefox it is?

 Not Original Poster here.

 I see the browser user agent purpose is twofold.

 1) To make all Tor users look identical to each other.
 2) To maintain compatibility with the rest of the Firefox users and the
 general web.

 Requirement of (1) is that whatever the user agent is, it must be the same
 for all TBB users. This also implies that the user agent can be anything
 we want, as long as it is the same for everyone, bearing in mind (2) it
 does not break things (such as the http charset header now).

 Keeping points (1) & (2) in mind, Torbutton should always keep the default
 Firefox User Agent, since adoption rate of new Firefoxes is rapid enough.
 However, it should always report the same WINDOWS version of Firefox (and
 the same version of windows) to maintain both compatibility and non-
 uniqueness of the users. This means that some regexp will be necessary.

 As an afterthought, something that could be possibly very cool, would be
 if the Torbutton could select a user agent at random, with the probability
 of each user agent being the same as the proportions on the web - and
 change this user agent with every New Identity or every webpage. This
 means that for example 30% of the time it will report itself as firefox 9
 running on winxp, 20% of the time as windows 7 internet explorer, and so
 on. I do not know whether this is a safe thing to do, from both the
 perspective of anonymity and not breaking the web.

-- 
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/5056#comment:2>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online