[tor-bugs] #31278 [Circumvention/Snowflake]: Chrome proxies hang with open idle connection

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#31278: Chrome proxies hang with open idle connection
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 Reporter:  cypherpunks          |          Owner:  (none)
     Type:  defect               |         Status:  new
 Priority:  Medium               |      Component:  Circumvention/Snowflake
  Version:                       |       Severity:  Normal
 Keywords:  snowflake-           |  Actual Points:
  webextension                   |
Parent ID:                       |         Points:
 Reviewer:                       |        Sponsor:
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 Using Chrome 75.0.3770.142 on Windows, with addon 0.0.7 and the latest
 static page at https://snowflake.torproject.org/snowflake that was
 committed 2019-07-27. Started Chrome, enabled addon, and opened 3 tabs
 with the static page. The addon and all 3 tabs all established good client
 connections within an hour or two, exchanged data both directions for a
 while, and then stalled out with the client connection staying open,
 preventing serving any other clients.

 All 4 client connections have been stuck in this state for 2 days now,
 with the addon just showing 1 connected and 0 in the past 24 hours, never
 changing, and the 3 tabs all just repeating "websocket --> WebRTC data:
 543 bytes" every couple minutes with no transfer size change or any data
 flowing in the other direction. The 3 tabs show connections to clients at
 different IP addresses, so I don't think it's just a user leaving their
 client window open forever.

 A similar test on Firefox with the same deployment date shows more
 expected behavior of a few clients served each day per tab or addon, with
 connections being closed after transferring data for a while and then
 later serving another client (so the dropped broker connection bug seems
 fixed there).

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Ticket URL: <https://trac.torproject.org/projects/tor/ticket/31278>
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