Bug 42343: Read built-in bridges from pt_config.json instead of preferences.

Merge Info

Related Issues

• #42343 (closed)
• mullvad-browser#xxxxx
• tor-browser-build#xxxxx

Backporting

Timeline

• Immediate: patchset needed as soon as possible
• Next Minor Stable Release: patchset that needs to be verified in nightly before backport
• Eventually: patchset that needs to be verified in alpha before backport
• No Backport (preferred): patchset for the next major stable

(Optional) Justification

• Emergency security update: patchset fixes CVEs, 0-days, etc
• Censorship event: patchset enables censorship circumvention
• Critical bug-fix: patchset fixes a bug in core-functionality
• Consistency: patchset which would make development easier if it were in both the alpha and release branches; developer tools, build system changes, etc
• Sponsor required: patchset required for sponsor
• Localization: typos and other localization changes that should be also in the release branch
• Other: please explain

Merging

• Merge to tor-browser - !fixups to tor-browser-specific commits, new features, security backports
• Merge to base-browser - !fixups to base-browser-specific commits, new features to be shared with mullvad-browser, and security backports
  • NOTE: if your changeset includes patches to both base-browser and tor-browser please clearly label in the change description which commits should be cherry-picked to base-browser after merging

Issue Tracking

• Link resolved issues with appropriate Release Prep issue for changelog generation

Review

Request Reviewer

• Request review from an applications developer depending on modified system:
  • NOTE: if the MR modifies multiple areas, please /cc all the relevant reviewers (since gitlab only allows 1 reviewer)
  • accessibility : henry
  • android : clairehurst, dan
  • build system : boklm
  • extensions : ma1
  • firefox internals (XUL/JS/XPCOM) : ma1
  • fonts : pierov
  • frontend (implementation) : henry
  • frontend (review) : donuts, richard
  • localization : henry, pierov
  • macos : clairehurst, dan
  • nightly builds : boklm
  • rebases/release-prep : dan, ma1, pierov, richard
  • security : ma1
  • signing : boklm, richard
  • updater : pierov
  • misc/other : pierov, richard

Requesting from Henry because they last changed the TorSettings module, so it should be still fresh in their mind, but also /cc @richard

Change Description

A while ago we decided to make the pt_config.json the authoritative file for built-in bridges.

While it's nice, it also involved 30 lines of shell script in tor-browser-build to transform the JSON file to preferences, and another 30 lines of JS to read an array from preferences.

Reading the JSON in JS is much easier, so we drop both the code to read the prefs, and the build code, which otherwise I would have had to duplicate for Android, now that we're porting the connect assist to it.

How Tested

1. Verified we don't have errors when initializing TorSettings
2. Manually called TorSettings._getBuiltinBridges and TorSettings.builtinBridgeTypes
3. Checked that TorSettings._getBuiltinBridges("obfs4") are actually randomized
4. Checked that setting built-in bridges still works