[tbb-bugs] #33962 [Applications/Tor Browser]: Uplift patch for 5741 (dns leak protection)

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#33962: Uplift patch for 5741 (dns leak protection)
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 Reporter:  acat                                 |          Owner:  tbb-
                                                 |  team
     Type:  task                                 |         Status:
                                                 |  needs_review
 Priority:  Medium                               |      Milestone:
Component:  Applications/Tor Browser             |        Version:
 Severity:  Normal                               |     Resolution:
 Keywords:  ReleaseTrainMigration                |  Actual Points:
  TorBrowserTeam202005R                          |
Parent ID:                                       |         Points:
 Reviewer:                                       |        Sponsor:
                                                 |  Sponsor58
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Comment (by acat):

 I think it makes sense, I'll do that.

 FWIW, after thinking a bit more, I'm not even sure if the patch I attached
 here would be acceptable for Mozilla: it's not clear to me that DNS should
 be disabled iff `network.proxy.socks_remote_dns = true` and
 `network.proxy.type = MANUAL`. First, there is UDP (e.g. WebRTC would stop
 working if there's a proxy with this patch). And second, I think for this
 approach you would also have to check whether `network.proxy.socks` is
 non-empty.

 Perhaps it's worth to follow this
 [https://bugzilla.mozilla.org/show_bug.cgi?id=751465#c26 suggestion] and
 just put this behind a `network.dns.disabled` pref instead of trying to
 find a logic for calculating whether DNS has to be disabled that works for
 both Mozilla and us.

--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/33962#comment:4>
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