Hey everyone!

Here are our meeting logs: http://meetbot.debian.net/tor-meeting/2022/tor-meeting.2022-06-16-15.59.html http://meetbot.debian.net/tor-meeting/2022/tor-meeting.2022-03-31-15.59.html

And our meeting pad: Anti-censorship work meeting pad

--------------------------------

Next meeting: Thursday June 23rd 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 check-in about the status of anti-censorship work at Tor. Coordinate collaboration between people/teams on anti-censorship at Tor.

== Links to Useful documents ==

* Our anti-censorship roadmap:         * Roadmap: https://gitlab.torproject.org/groups/tpo/anti-censorship/-/boards     * The anti-censorship team's wiki page:         * https://gitlab.torproject.org/tpo/anti-censorship/team/-/wikis/home     * Past meeting notes can be found at:         * https://lists.torproject.org/pipermail/tor-project/     * Tickets that need reviews:  from sponsors we are working on:         * All needs review tickets: https://gitlab.torproject.org/groups/tpo/anti-censorship/-/merge_requests?sc...         * Sponsor 28             * must-do tickets: https://gitlab.torproject.org/groups/tpo/-/milestones/10             * possible tickets: https://gitlab.torproject.org/groups/tpo/-/issues?scope=all&utf8=%E2%9C%...         * Sponsor 96             * https://gitlab.torproject.org/groups/tpo/-/milestones/24

== Announcements ==

* Distributed Snowflake, IP Change Rate Measurement is ready for merge src Shell         * Shell will handle the merge         * Will wait for a day when others are online to do the deployment         * Will deploy both new features at once

== Discussion ==

* What is the status of adjusting snowflake (pion) DTLS signature to avoid blocking in Russia? (Based on offset of supported_groups extension.)         * https://gitlab.torproject.org/tpo/anti-censorship/censorship-analysis/-/issu...         * https://github.com/pion/dtls/pull/474         * https://ntc.party/t/webrtc/2174/21         * https://gitlab.torproject.org/tpo/community/support/-/issues/40050 (generally)         * UDP packets matching the pattern `^\x16\xfe[\xfd\xff].{X}\x00\x1d\x00\x17\x00\x18` are getting blocked, where X is a small number of enumerated byte offsets, and \x00\x1d\x00\x17\x00\x18 is the supported_groups extension. One of the offsets happens to match where pion/dtls places the extension in its Client Hello.         * Concise description of the current situation: snowflake connections are blocked when either peer in the connection is Pion-based (e.g. snowflake-client or proxy-go) and takes the role of the DTLS client.             * Put another way, the connection is ok if: the proxy is a browser proxy (not proxy-go) and snowflake-client operates as a DTLS server, not client         * Pull request 474 has the risk of creating a new, even more distinctive fingerprint             * So does altering the offset of supported_groups without changing other aspects of the fingerprint         * One idea is to make a patch or fork of pion/dtls with either pull request 474 or some other change that alters the offset, then ask people to test it             * https://gitweb.torproject.org/builders/tor-browser-build.git/commit/?id=7ffd... is a past temporary fork for a fingerprinting fix             * https://archive.org/details/snowflake-ru_snowflake_fix-20211208-ae7cc478fd34 is the resulting bundle that we asked people to test             * Shell will create a ticket for releasing a version of Snowflake/TorBrowser with patch applied

== Actions ==

== Interesting links ==

== Reading group ==

* We will discuss "Even Censors Have a Backup: Examining China's Double HTTPS Censorship Middleboxes" on June 23         * https://dl.acm.org/doi/10.1145/3473604.3474559         * 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 2022-06-16 (will miss meeting) Last week:     - conjure station-side changes     - updated conjure test environment using cloud-init vms This week:     - continued work on conjure PT     - continue snowflake maintenance tasks Needs help with:

dcf: 2022-06-16     Last week:         - snowflake CDN bookkeeping https://gitlab.torproject.org/tpo/anti-censorship/team/-/wikis/Snowflake-cos...         - commented on dnstt pluggable transport client https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/trac/...         - commented on restarts for snowflake probetest https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowf...     Next week:         - look at STATUS VERSION proposal https://gitlab.torproject.org/tpo/core/torspec/-/merge_requests/63     Help with:

meskio: 2022-06-02     Last week:             - use systemd to run bridgedb (team#72)             - update debian package for snowflake (snowflake#40143)             - don't use entropy in snowflake tests (snowflake!96)             - contact cymru about their builtin bridges, as they have an old version of obfs4proxy     Next week:             - start working on gettor (rdsys#105)

Shelikhoo: 2022-06-16    Last Week:      - [Merge Request] Add Distributed Snowflake Server Support (snowflake!87)      - [Merge Request] Distributed Snowflake Bridges (Javascript ver.) (snowflake-webext!29)      - [Merge Request] Implement metrics to measure snowflake churn (https://gitlab.torproject.org/tpo/anti-censorship/pluggable-transports/snowf...) (snowflake!95)         - [Merge Request Awaiting] Add SOCKS5 forward proxy support to snowflake (snowflake!64)         - [Discussion & Deployment] Migrating Controlling git repo to Tor Gitlab Instance (shelikhoo/LogCollectorAncillary#5) <- awaiting/blocked         - [Research & Discussion] Discussion about the possibility of adding PT support to V2Ray to serve the role of HTTPT (https://gitlab.torproject.org/tpo/anti-censorship/team/-/issues/82)         - [Investigate] China "Anti-Fraud" Webpage Redirection Censorship (censorship-analysis#40026): update the research based on updated ooni result    Next Week:           - [Deployment] Snowflake Broker           - [Coding & Deployment] Proposal: Centralized Probe Result Collector (anti-censorship/team#54)           - [Research & Coding] WebSocket + CDN Based Probe Control Connection Forwarder (shelikhoo/LogCollectorAncillary#3)           - [Investigate] China "Anti-Fraud" Webpage Redirection Censorship (censorship-analysis#40026): update the research based on updated ooni result

Itchy Onion: 2022-06-16     Last week:         - ongoing debugging s28 issues 81 (snowflake crashes in stree-testing)         - taking over part of testing snowflake     This week:         - ongoing debugging s28 issues 81, fixing a leaking file descriptor issue         - taking over part of testing snowflake