[tbb-bugs] #33931 [Applications/Tor Browser]: obfs4 bridges are used instead of meek if meek is selected in Tor Browser for Android alpha

[Tor Bug Tracker & Wiki]

#33931: obfs4 bridges are used instead of meek if meek is selected in Tor Browser
for Android alpha
-------------------------------------------------+-------------------------
 Reporter:  gk                                   |          Owner:  tbb-
                                                 |  team
     Type:  defect                               |         Status:
                                                 |  needs_review
 Priority:  High                                 |      Milestone:
Component:  Applications/Tor Browser             |        Version:
 Severity:  Normal                               |     Resolution:
 Keywords:  tbb-mobile, tbb-parity, tbb-         |  Actual Points:
  regression, TorBrowserTeam202004               |
Parent ID:                                       |         Points:
 Reviewer:                                       |        Sponsor:
-------------------------------------------------+-------------------------
Changes (by sysrqb):

 * status:  new => needs_review


Comment:

 Okay. I forgot String equality comparison in Java should use `.equal()`
 instead of `==`, so that was a waste of some time. In any case, for
 review:

 Branch `bug33931_00` in my `tor-android-service` repo for one piece of
 this.

 https://gitweb.torproject.org/user/sysrqb/tor-android-
 service.git/commit/?h=bug33931_00&id=769b3c85de468bb23fbb891266ab6cbb9c662e13

 And branch `bug33931_00` in my `tor-browser-build` repo:

 https://gitweb.torproject.org/user/sysrqb/tor-browser-
 build.git/commit/?h=bug33931_00&id=91e6aec4f60783fc0008d4d3c60c29ddecafac0d

 The summary of these patches is that tor-android-service encodes (within
 the first byte) if the following datastream is arbitrary custom bridges or
 if it comes from a list of default bridges (and which specific bridge
 type, if applicable).

 When the first byte is:
   - 1, then the stream contains arbitrary bridges
   - 0, then the stream is all default bridges
   - 2, then the stream is all default bridges and only obfs4 bridges
 should be used after parsing
   - 3, then the stream is all default bridges and only meek_lite bridges
 should be used after parsing

 TOPL receives this and now handles them appropriately.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/33931#comment:3>
Tor Bug Tracker & Wiki <https://trac.torproject.org/>
The Tor Project: anonymity online