* Have a project team collection, content is the same as ticket team (but
potentially ticket team allows people to opt out of updates on specific
tickets, while project team isn't tied to any specific ticket or other child
object)
* Have a project followers collection, and address it in ticket comments in
addition to the already used recipients (project, ticket team, ticket
followers)
- Allow client to specify recipients that don't need to be delivered to
- When fetching recipient, recognize collections and don't try to deliver to
them
- Remember collections in DB, and use that to skip HTTP delivery
* Adapt DB related code to return the InstanceId and RemoteSharerId
* Previously, when fetching a known shared key, we were running a DB
check/update for the shared usage record. I noticed - and hopefully I
correctly noticed - that this check already runs when we discover the keyId
points to a shared key we already know. So, after successful sig
verification, there's no need to run the check again. So I removed it.
Before, things worked like this:
* Only signatures of Ed25519 keys could be verified
* Key encoding placed the plain binary Ed25519 key in the PEM, instead of the
key's ASN1 encoding
With this patch it now works like this:
* Ed25519 signatures are supported as before
* RSA keys are now supported too, assuming RSA-SHA256 signatures
* Both Ed25519 and RSA keys are encoded and decoded using actual PEM with ASN1
Previously, when verifying an HTTP signature and we fetched the key and
discovered it's shared, we'd fetch the actor and make sure it lists the key URI
in the `publicKey` field. But if we already knew the key, had it cached in our
DB, we wouldn't check the actor at all, despite not knowing whether it lists
the key.
With this patch, we now always GET the actor when the key is shared,
determining the actor URI from the `ActivityPub-Actor` request header, and we
verify that the actor lists the key URI. We do that regardless of whether or
not we have the key in the DB, although these two cases and handled in
different parts of the code right now (for a new key, it's in Web.ActivityPub
fetchKey; for a known key, it's in Vervis.Foundation httpVerifySig).
If the key we fetched is a shared key, the only way to determine the actor to
which the signature applies is to read the HTTP header ActivityPub-Actor. But
if it's a personal key, we can detect the actor by checking the key's owner
field. Still, if that actor header is provided, we now compare it to the key
owner and make sure they're identical.
When fetching a key that is embedded in the actor document, we were already
comparing the actor ID with the actor header, so that part didn't require
changes.
When a local user wants to publish an activity, we were always GETing the
recipient actor, so that we could determine their inbox and POST the activity
to it. But now, instead, whenever we GET an actor (whether it's for the key sig
verification or for determining inbox URI), we keep their inbox URI in the
database, and we don't need to GET it again next time.
Using a dedicated type allows to record in the type the guarantees that we
provide, such as scheme being HTTPS and authority being present. Allows to
replace ugly `fromJust` and such with direct field access.
Before, there was a single key used as a personal key for all actors. Now,
things work like this:
- There are 2 keys, each time one is rotated, this way the old key remains
valid and we can freely rotate without a risk of race conditions on other
servers and end up with our posts being rejected
- The keys are explicitly instance-scope keys, all actors refer to them
- We add the ActivityPub-Actor header to all activity POSTs we send, to declare
for which specific actor our signature applies. Activities and otherwise
different payloads may have varying ways to specify attribution; using this
header will be a standard uniform way to specify the actor, regardless of
payload format. Of course, servers should make sure the actual activity is
attributed to the same actor we specified in the header. (This is important
with instance-scope keys; for personal keys it's not critical)
