Hi everyone!

Here are our meeting logs:

http://meetbot.debian.net/tor-meeting/2021/tor-meeting.2021-09-02-16.00.html

and our meeting pad:

Anti-censorship work meeting pad --------------------------------

Next meeting: Thursday September 2nd 16:00 UTC

Weekly meetings, every Thursday at 16:00 UTC, in #tor-meeting at OFTC (channel is logged while meetings are in progress)

== Goal of this meeting ==

Weekly checkin about the status of anti-censorship work at Tor. Coordinate collaboration between people/teams on anti-censorship at Tor.

== Announcements ==

Job opening on the anti-censorship team: https://www.torproject.org/about/jobs/software-developer-anticensorship-2/ \o/

== Discussion ==

- CPU use in proxies and bridge

- https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowf...

- bridge is sitting at about 200% CPU: about 30% tor, 170% snowflake-server

- might be worth doing one round of profiling?

- how to profile the bridge? in production or separately?

- can use snowbox as a simulation

- proxies can control CPU use with -capacity option

- Reading group?

- we'll read "BlindTLS" https://dl.acm.org/doi/10.1145/3473604.3474564

- DocsHackathon:

- Add a new support item about using Tor in China: https://gitlab.torproject.org/tpo/web/support/-/issues/210

- Merging support.torproject.org/gettor into support.torproject.org/censorship

- TM censorship update

- do any of our gettor endpoints work in Turkmenistan?

- archive.org seems to be ok for DNS, HTTP, and HTTPS

== Actions ==

Update the monthly report for July + August: https://pad.riseup.net/p/l7d6oBd40EQa3u7cFxIk

== Interesting links ==

https://ntc.party/t/an-open-encyclopedia-of-internet-censorship-persian/1223

ACM FOCI 2021 papers https://dl.acm.org/doi/proceedings/10.1145/3473604

"Even Censors Have a Backup: Examining China's Double HTTPS Censorship Middleboxes" https://dl.acm.org/doi/10.1145/3473604.3474559

"Measuring QQMail's automated email censorship in China" https://dl.acm.org/doi/10.1145/3473604.3474560

"A multi-perspective view of Internet censorship in Myanmar" https://dl.acm.org/doi/10.1145/3473604.3474562

"Exploring Simple Detection Techniques for DNS-over-HTTPS Tunnels" https://dl.acm.org/doi/10.1145/3473604.3474563

"BlindTLS: Circumventing TLS-based HTTPS censorship" https://dl.acm.org/doi/10.1145/3473604.3474564

USENIX Security 2021 papers https://www.usenix.org/conference/usenixsecurity21/technical-sessions

"Domain Shadowing: Leveraging Content Delivery Networks for Robust Blocking-Resistant Communications" https://www.usenix.org/conference/usenixsecurity21/presentation/wei

"How Great is the Great Firewall? Measuring China's DNS Censorship" https://www.usenix.org/conference/usenixsecurity21/presentation/hoang

"Balboa: Bobbing and Weaving around Network Censorship" https://www.usenix.org/conference/usenixsecurity21/presentation/rosen

"Weaponizing Middleboxes for TCP Reflected Amplification" https://www.usenix.org/conference/usenixsecurity21/presentation/bock

"Defeating DNN-Based Traffic Analysis Systems in Real-Time With Blind Adversarial Perturbations" https://www.usenix.org/conference/usenixsecurity21/presentation/nasr

== Reading group ==

We will discuss "BlindTLS: Circumventing TLS-based HTTPS censorship" on 2021-09-23

https://dl.acm.org/doi/10.1145/3473604.3474564

Questions to ask and goals to have:

What aspects of the paper are questionable?

Are there immediate actions we can take based on this work?

Are there long-term actions we can take based on this work?

Is there future work that we want to call out, in hopes that others will pick it up?

== Updates ==

Name: This week: - What you worked on this week. Next week: - What you are planning to work on next week. Help with:

- Something you need help with.

cecylia (cohosh): last updated 2021-09-02 Last week: - hiring tasks for ac team and network team - more s28 scrimmage work - got snowflake working in shadow

- https://github.com/shadow/shadow/pull/1601

- implemented parsing of networkstatus documents for rdsys (rdsys!14) - wrote a draft plug for implementing RTCPeerConnection for v3 manifests - reviewed GetTor implementation in rdsys (rdsys!11) - reviewed snowflake!52 - couple other small reviews This week: - snowflake package documentation and API changes (snowflake#40063) - more rdsys + BridgeDB deployment work - network simulations of Snowflake with shadow - censorship measurement tests and tools - lots of miscellaneous gitlab TODOs Needs help with:

- feedback on v3 plug: https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowf...

arlolra: 2021-08-12

Last week:

- Migrate to v3 of the webextension manifest

Next week:

- Maybe get back to snowflake-webext #10

- Write up the pitch for our use case for supporting creating PeerConnections in background service workers https://github.com/w3c/webrtc-extensions/issues/77

Help with:

-

dcf: 2021-09-02

Last week (since 2021-08-19):

- helped review snowflake-client SOCKS args https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowf...

- more investigation of blocking in Turkmenistan https://gitlab.torproject.org/tpo/community/support/-/issues/40030#note_2748...

- helped analyze go mod issue with goptlib https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowf...

- attended pluggable transports meetup https://internetfreedomfestival.org/wiki/index.php/September_2_2021_GM

Next week:

- fix meek-client test errors https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/meek/...

- identify cause and fix for the goptlib go.mod issue https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowf...

- reply to Alexander Mages re SCTP pluggable transport https://lists.torproject.org/pipermail/anti-censorship-team/2021-August/0001...

Help with:

agix:2021-07-15

Last week:

-Off due to final exams

Next week:

-Work on bridgebox for rdsys

-More research on httpt #4

Help with:

-

hanneloresx: 2021-3-4

Last week:

- Submitted MR for bridgestrap issue #14

Next week:

- Finish bridgestrap #14

- Find new issue to work on

Help with:

-

maxb: 2021-07-15

Last week:

- Opened https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowf... re: utls for broker negotiation

- Worked on github.com/max-b/nat-testing for https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowf...

- Added a snowflake-proxy-no-nat and a snowflake-client-no-nat to help with debugging

- Successfully making connections from snowflake-client and snoflake-client-no-nat through the snowflake-proxy-no-nat, but not having any success with the snowflake-proxy (with nat).

- Added a local dockerized STUN server

Next week:

- Use wireshark to figure out the difference between successful snowflake-proxy-no-nat and unsuccessful snowflake-proxy-nat

- Work on implementing different NAT types, particularly in a way that's conducive to automatic testing

- Add testing wrapper w/ "pass/fail" conditions

meskio: 2021-09-02

Last week:

- work on the moat Censorsip snapshot (bridgedb#40025)

- merge gettor implemenation (rdsys!11)

- update snowflake debian package (snowflake#19409)

- write gettor documentation (rdsys#44)

- test fixes into snowflake (snowflake!55)

- run rdsys tests in the CI (rdsys#58)

- review networkstatus parser (rdsys!14)

- review rearquitecture to smaller docker image for snowflake-proxy (docker-snowflake-proxy!1)

- review and merge gettor updater script (gettor!17)

- review snowflake Check error for calls to preparePeerConnection (snowflake!54)

- review and merge obfs4 docker build for multiple archs (docker-obfs4-bridge!4)

Next week:

- implement censorship snapsot available on moat (bridgedb#40025)

- add more providers to gettor (rdsys#43)

- get the snowflake debian package reviewed by a DD (snowflake#19409)

Help with:

-