Anti-censorship team report: July 2020

Tor’s anti-censorship team writes monthly reports to keep the world updated on its progress. This blog post summarizes the anti-censorship work we got done in July 2020. Let us know if you have any questions or feedback!

Snowflake

• Rolled out a feature to match up Snowflake proxies and clients based on their NAT type. This will drastically improve performance for Snowflake clients behind restrictive NATs.
  https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowflake/-/issues/34129

• Added more STUN servers to default configuration in Tor Browser. This solves two issues: it allows clients to perform NAT type discovery to be matched up with more compatible proxies, and it unblocks Snowflake in areas that block access to Google’s STUN servers.
  https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowflake/-/issues/30579

• Adapted Snowflake CI to the new GitLab instance.
  https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowflake/-/issues/40003

• Investigated proxy-go timeouts.
  https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowflake/-/issues/30498

• Fixed a small bug that could cause infinite hangs in Snowflake proxies and clients.
  https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowflake/-/issues/40005

• Worked on a docker container for easy deployment of Snowflake proxies.
  https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowflake/-/issues/40002

• Moved forward with our Android app UI.
  https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowflake-mobile/-/issues/11

BridgeDB

• Fixed a critical bug that prevented BridgeDB from reloading bridge descriptors every 30 minutes, as it’s supposed to. This bug significantly delayed the time until a new bridge was handed out to users. Hopefully, the patch will result in bridge operators seeing more users.
  https://gitlab.torproject.org/tpo/anti-censorship/bridgedb/-/issues/40001

• We are spending an increasing amount of time planning and experimenting with a reimplementation of BridgeDB. The reimplementation will make it easier to integrate new components like bridgestrap and new distributors like Salmon.
  https://gitlab.torproject.org/tpo/anti-censorship/bridgedb/-/issues/32900

• Added internal metrics to BridgeDB’s metrics. You can find the latest internal metrics here:
  https://collector.torproject.org/recent/bridgedb-metrics/
  https://gitlab.torproject.org/tpo/anti-censorship/bridgedb/-/issues/31422

• Wrote a patch that helps BridgeDB take into account bridge reachability measurements from wolpertinger.
  https://gitlab.torproject.org/tpo/anti-censorship/bridgedb/-/issues/34260

• Fixed incorrect and missing parts in BridgeDB’s metrics specification.
  https://gitlab.torproject.org/tpo/anti-censorship/bridgedb/-/issues/40003

• Fixed a broken link in BridgeDB’s README and ported BridgeDB’s “make pylint” target to Python 3.
  https://gitlab.torproject.org/tpo/anti-censorship/bridgedb/-/issues/33647

• Fixed a bug that would confuse BridgeDB when it dealt with Gmail’s quoted responses.
  https://gitlab.torproject.org/tpo/anti-censorship/bridgedb/-/issues/33835

• Made progress on creating a research plan for understanding the issues that users run into when interacting with BridgeDB.
  https://gitlab.torproject.org/tpo/ux/research/-/issues/4

Miscellaneous

• Simplified bridgestrap’s code base and fixed a bug in its caching system.
  https://gitlab.torproject.org/tpo/anti-censorship/bridgestrap/

• Merged a volunteer-provided bridge setup guide for Windows.
  https://community.torproject.org/relay/setup/bridge/windows/