Bug 42022: Prevent extension search engines from breaking the whole search system

Merge Info

Related Issues

• tor-browser#42022 (closed)
• #213 (closed)

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
• 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
• Other: please explain

Merging

• Merge to mullvad-browser - !fixups to mullvad-browser-specific commits, new features, security backports
• Merge to base-browser -!fixups to base-browser-specific commits, new features to be shared with tor-browser
  • NOTE: if your changeset includes patches to both base-browser and mullvad-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 : dan
  • build system : boklm
  • extensions : ma1
  • firefox internals (XUL/JS/XPCOM) : ma1
  • fonts : pierov
  • frontend (implementation) : henry
  • frontend (review) : donuts, richard
  • localization : henry, pierov
  • nightly builds : boklm
  • rebases/release-prep : dan_b, ma1, pierov, richard
  • security : ma1
  • signing : boklm, richard
  • updater : pierov
  • misc/other : pierov, richard

Change Description

Restored the Leta search engine, and added a patch to contain the exception to the code handling the extensions.

I think the patch is a good candidate also for Base Browser, but testing it in Mullvad Browser is easier, so I'm opening the MR here.

Moreover, we should uplift it, I think, even though Mozilla is unlikely to hit a similar situation.