Since we reject cross-domain redirects, this doesn’t yet
make a difference, but it’s requried for stricter checking
subsequent commits will introduce.
To make sure (and in case we ever decide to reallow
cross-domain redirects) also use the final location
for containment and reachability checks.
If it’s not already in the database,
it must be counterfeit (or just not exists at all)
Changed test URLs were only ever used from "local: false" users anyway.
This brings it in line with its name and closes an,
in practice harmless, verification hole.
This was/is the only user of contain_origin making it
safe to change the behaviour on actor-less objects.
Until now refetched objects did not ensure the new actor matches the
domain of the object. We refetch polls occasionally to retrieve
up-to-date vote counts. A malicious AP server could have switched out
the poll after initial posting with a completely different post
attribute to an actor from another server.
While we indeed fell for this spoof before the commit,
it fortunately seems to have had no ill effect in practice,
since the asociated Create activity is not changed. When exposing the
actor via our REST API, we read this info from the activity not the
object.
This at first thought still keeps one avenue for exploit open though:
the updated actor can be from our own domain and a third server be
instructed to fetch the object from us. However this is foiled by an
id mismatch. By necessity of being fetchable and our longstanding
same-domain check, the id must still be from the attacker’s server.
Even the most barebone authenticity check is able to sus this out.
Such redirects on AP queries seem most likely to be a spoofing attempt.
If the object is legit, the id should match the final domain anyway and
users can directly use the canonical URL.
The lack of such a check (and use of the initially queried domain’s
authority instead of the final domain) was enabling the current exploit
to even affect instances which already migrated away from a same-domain
upload/proxy setup in the past, but retained a redirect to not break old
attachments.
(In theory this redirect could, with some effort, have been limited to
only old files, but common guides employed a catch-all redirect, which
allows even future uploads to be reachable via an initial query to the
main domain)
Same-domain redirects are valid and also used by ourselves,
e.g. for redirecting /notice/XXX to /objects/YYY.
Only real change here is making MRF rejects log as debug instead of info (https://akkoma.dev/AkkomaGang/akkoma/issues/234)
I don't know if it's the best way to do it, but it seems it's just MRF using this and almost always this is intended.
The rest are just minor docs changes and syncing the restricted nicknames stuff.
I compiled and ran my changes with Docker and they all work.
Co-authored-by: r3g_5z <june@terezi.dev>
Reviewed-on: https://akkoma.dev/AkkomaGang/akkoma/pulls/313
Co-authored-by: @r3g_5z@plem.sapphic.site <june@girlboss.ceo>
Co-committed-by: @r3g_5z@plem.sapphic.site <june@girlboss.ceo>
Current FedSocket implementation has a bunch of problems. It doesn't
have proper error handling (in case of an error the server just doesn't
respond until the connection is closed, while the client doesn't match
any error messages and just assumes there has been an error after 15s)
and the code is full of bad descisions (see: fetch registry which uses
uuids for no reason and waits for a response by recursively querying a
ets table until the value changes, or double JSON encoding).
Sometime ago I almost completed rewriting fedsockets from scrach to
adress these issues. However, while doing so, I realized that fedsockets
are just too overkill for what they were trying to accomplish, which is
reduce the overhead of federation by not signing every message.
This could be done without reimplementing failure states and endpoint
logic we already have with HTTP by, for example, using TLS cert auth,
or switching to a more performant signature algorithm. I opened
https://git.pleroma.social/pleroma/pleroma/-/issues/2262 for further
discussion on alternatives to fedsockets.
From discussions I had with other Pleroma developers it seems like they
would approve the descision to remove them as well,
therefore I am submitting this patch.
Validate the content-type of the response when fetching an object,
according to https://www.w3.org/TR/activitypub/#x3-2-retrieving-objects.
content-type headers had to be added to many mocks in order to support
this, some of this was done with a regex. While I did go over the
resulting files to check I didn't modify anything unrelated, there is a
possibility I missed something.
Closes pleroma#1948
