Avoid Sentry exceptions when attackers try to stuff invalid emails. The
browser performs form field validation that should normally prevent this
from occurring, so we just return 422 without validation error messages.
Also:
- extract redirect_to_session_magic_link helper
- some controller refactoring and cleanup
Users could reorder columns they didn't have access to. Fixed by
limiting ColumnScoped to User::Accessor#accessible_columns.
References https://hackerone.com/reports/3449905
* robots.txt: "Please, don't come in." If a page is directly linked, the
URL can still appear in search results, though.
* X-Robots-Tag: "If you're here, forget what you saw." Works even if the
crawler ignores robots.txt or reaches a page via external link. Can
remove already-indexed pages.
* Public boards may not be indexed. They're meant for "anyone with the
link" private sharing, not worldwide publishing.
This is a great, solid alternative to CSRF tokens for CSRF protection
when we aren't worried about older browsers or other kind of actors
doing modifying requests in our app, and could be a good test for future
upstreaming to Rails (although there we'd need to continue using CSRF
tokens or at least letting people opt out manually).
Let's start checking the header and reporting on it when CSRF fails or
when it doesn't match the other checks Rails does, and then promote this
to be the only way to defend from CSRF.
Instead of writer pinning, we'll track the last transaction ID of each
write in the session. Then on each read we'll wait for the replica to
report that this transaction is available.
If it doesn't become available within a reasonable timeout, we'll
proceed anyway, and accept the possibility of a stale read.
The hope here is that most of the time, the replica is caught up in the
time between a write request and the following read request. If it's
not, we now have a little tolerance to wait for it, which hopefully
proves enough to stale reads are not encountered in normal use.
We also disable the writer affinity opt-out mechanism that we had
before, since we will no longer be using writer affinity at the load
balancer.
David Heinemeier Hansson