gotosocial/internal/federation/federatingactor.go

325 lines
11 KiB
Go

// GoToSocial
// Copyright (C) GoToSocial Authors admin@gotosocial.org
// SPDX-License-Identifier: AGPL-3.0-or-later
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU Affero General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package federation
import (
"context"
"encoding/json"
"errors"
"fmt"
"io"
"net/http"
"net/url"
"strings"
"codeberg.org/gruf/go-kv"
"github.com/superseriousbusiness/activity/pub"
"github.com/superseriousbusiness/activity/streams"
"github.com/superseriousbusiness/activity/streams/vocab"
"github.com/superseriousbusiness/gotosocial/internal/ap"
"github.com/superseriousbusiness/gotosocial/internal/db"
"github.com/superseriousbusiness/gotosocial/internal/gtserror"
"github.com/superseriousbusiness/gotosocial/internal/log"
)
// IsASMediaType will return whether the given content-type string
// matches one of the 2 possible ActivityStreams incoming content types:
// - application/activity+json
// - application/ld+json;profile=https://w3.org/ns/activitystreams
//
// Where for the above we are leniant with whitespace and quotes.
func IsASMediaType(ct string) bool {
var (
// First content-type part,
// contains the application/...
p1 string = ct //nolint:revive
// Second content-type part,
// contains AS IRI if provided
p2 string
)
// Split content-type by semi-colon.
sep := strings.IndexByte(ct, ';')
if sep >= 0 {
p1 = ct[:sep]
p2 = ct[sep+1:]
}
// Trim any ending space from the
// main content-type part of string.
p1 = strings.TrimRight(p1, " ")
switch p1 {
case "application/activity+json":
return p2 == ""
case "application/ld+json":
// Trim all start/end space.
p2 = strings.Trim(p2, " ")
// Drop any quotes around the URI str.
p2 = strings.ReplaceAll(p2, "\"", "")
// End part must be a ref to the main AS namespace IRI.
return p2 == "profile=https://www.w3.org/ns/activitystreams"
default:
return false
}
}
// federatingActor wraps the pub.FederatingActor
// with some custom GoToSocial-specific logic.
type federatingActor struct {
sideEffectActor pub.DelegateActor
wrapped pub.FederatingActor
}
// newFederatingActor returns a federatingActor.
func newFederatingActor(c pub.CommonBehavior, s2s pub.FederatingProtocol, db pub.Database, clock pub.Clock) pub.FederatingActor {
sideEffectActor := pub.NewSideEffectActor(c, s2s, nil, db, clock)
sideEffectActor.Serialize = ap.Serialize // hook in our own custom Serialize function
return &federatingActor{
sideEffectActor: sideEffectActor,
wrapped: pub.NewCustomActor(sideEffectActor, false, true, clock),
}
}
// PostInboxScheme is a reimplementation of the default baseActor
// implementation of PostInboxScheme in pub/base_actor.go.
//
// Key differences from that implementation:
// - More explicit debug logging when a request is not processed.
// - Normalize content of activity object.
// - *ALWAYS* return gtserror.WithCode if there's an issue, to
// provide more helpful messages to remote callers.
// - Return code 202 instead of 200 on successful POST, to reflect
// that we process most side effects asynchronously.
func (f *federatingActor) PostInboxScheme(ctx context.Context, w http.ResponseWriter, r *http.Request, scheme string) (bool, error) {
l := log.WithContext(ctx).
WithFields([]kv.Field{
{"userAgent", r.UserAgent()},
{"path", r.URL.Path},
}...)
// Ensure valid ActivityPub Content-Type.
// https://www.w3.org/TR/activitypub/#server-to-server-interactions
if ct := r.Header.Get("Content-Type"); !IsASMediaType(ct) {
const ct1 = "application/activity+json"
const ct2 = "application/ld+json;profile=https://w3.org/ns/activitystreams"
err := fmt.Errorf("Content-Type %s not acceptable, this endpoint accepts: [%q %q]", ct, ct1, ct2)
return false, gtserror.NewErrorNotAcceptable(err)
}
// Authenticate request by checking http signature.
ctx, authenticated, err := f.sideEffectActor.AuthenticatePostInbox(ctx, w, r)
if err != nil {
return false, gtserror.NewErrorInternalError(err)
}
if !authenticated {
err = errors.New("not authenticated")
return false, gtserror.NewErrorUnauthorized(err)
}
/*
Begin processing the request, but note that we
have not yet applied authorization (ie., blocks).
*/
// Obtain the activity; reject unknown activities.
activity, errWithCode := resolveActivity(ctx, r)
if errWithCode != nil {
return false, errWithCode
}
// Set additional context data. Primarily this means
// looking at the Activity and seeing which IRIs are
// involved in it tangentially.
ctx, err = f.sideEffectActor.PostInboxRequestBodyHook(ctx, r, activity)
if err != nil {
return false, gtserror.NewErrorInternalError(err)
}
// Check authorization of the activity; this will include blocks.
authorized, err := f.sideEffectActor.AuthorizePostInbox(ctx, w, activity)
if err != nil {
if errors.As(err, new(errOtherIRIBlocked)) {
// There's no direct block between requester(s) and
// receiver. However, one or more of the other IRIs
// involved in the request (account replied to, note
// boosted, etc) is blocked either at domain level or
// by the receiver. We don't need to return 403 here,
// instead, just return 202 accepted but don't do any
// further processing of the activity.
return true, nil
}
// Real error has occurred.
return false, gtserror.NewErrorInternalError(err)
}
if !authorized {
// Block exists either from this instance against
// one or more directly involved actors, or between
// receiving account and one of those actors.
err = errors.New("blocked")
return false, gtserror.NewErrorForbidden(err)
}
// Copy existing URL + add request host and scheme.
inboxID := func() *url.URL {
u := new(url.URL)
*u = *r.URL
u.Host = r.Host
u.Scheme = scheme
return u
}()
// At this point we have everything we need, and have verified that
// the POST request is authentic (properly signed) and authorized
// (permitted to interact with the target inbox).
//
// Post the activity to the Actor's inbox and trigger side effects .
if err := f.sideEffectActor.PostInbox(ctx, inboxID, activity); err != nil {
// Special case: We know it is a bad request if the object or
// target properties needed to be populated, but weren't.
// Send the rejection to the peer.
if errors.Is(err, pub.ErrObjectRequired) || errors.Is(err, pub.ErrTargetRequired) {
// Log the original error but return something a bit more generic.
l.Debugf("malformed incoming Activity: %q", err)
err = errors.New("malformed incoming Activity: an Object and/or Target was required but not set")
return false, gtserror.NewErrorBadRequest(err, err.Error())
}
// There's been some real error.
err = fmt.Errorf("PostInboxScheme: error calling sideEffectActor.PostInbox: %w", err)
return false, gtserror.NewErrorInternalError(err)
}
// Side effects are complete. Now delegate determining whether
// to do inbox forwarding, as well as the action to do it.
if err := f.sideEffectActor.InboxForwarding(ctx, inboxID, activity); err != nil {
// As a not-ideal side-effect, InboxForwarding will try
// to create entries if the federatingDB returns `false`
// when calling `Exists()` to determine whether the Activity
// is in the database.
//
// Since our `Exists()` function currently *always*
// returns false, it will *always* attempt to insert
// the Activity. Therefore, we ignore AlreadyExists
// errors.
//
// This check may be removed when the `Exists()` func
// is updated, and/or federating callbacks are handled
// properly.
if !errors.Is(err, db.ErrAlreadyExists) {
// Failed inbox forwarding is not a show-stopper,
// and doesn't even necessarily denote a real error.
l.Warnf("error calling sideEffectActor.InboxForwarding: %q", err)
}
}
// Request is now undergoing processing. Caller
// of this function will handle writing Accepted.
return true, nil
}
// resolveActivity is a util function for pulling a
// pub.Activity type out of an incoming POST request.
func resolveActivity(ctx context.Context, r *http.Request) (pub.Activity, gtserror.WithCode) {
// Tidy up when done.
defer r.Body.Close()
b, err := io.ReadAll(r.Body)
if err != nil {
err = fmt.Errorf("error reading request body: %w", err)
return nil, gtserror.NewErrorInternalError(err)
}
var rawActivity map[string]interface{}
if err := json.Unmarshal(b, &rawActivity); err != nil {
err = fmt.Errorf("error unmarshalling request body: %w", err)
return nil, gtserror.NewErrorInternalError(err)
}
t, err := streams.ToType(ctx, rawActivity)
if err != nil {
if !streams.IsUnmatchedErr(err) {
// Real error.
err = fmt.Errorf("error matching json to type: %w", err)
return nil, gtserror.NewErrorInternalError(err)
}
// Respond with bad request; we just couldn't
// match the type to one that we know about.
err = errors.New("body json could not be resolved to ActivityStreams value")
return nil, gtserror.NewErrorBadRequest(err, err.Error())
}
activity, ok := t.(pub.Activity)
if !ok {
err = fmt.Errorf("ActivityStreams value with type %T is not a pub.Activity", t)
return nil, gtserror.NewErrorBadRequest(err, err.Error())
}
if activity.GetJSONLDId() == nil {
err = fmt.Errorf("incoming Activity %s did not have required id property set", activity.GetTypeName())
return nil, gtserror.NewErrorBadRequest(err, err.Error())
}
// If activity Object is a Statusable, we'll want to replace the
// parsed `content` value with the value from the raw JSON instead.
// See https://github.com/superseriousbusiness/gotosocial/issues/1661
// Likewise, if it's an Accountable, we'll normalize some fields on it.
ap.NormalizeIncomingActivityObject(activity, rawActivity)
return activity, nil
}
/*
Functions below are just lightly wrapped versions
of the original go-fed federatingActor functions.
*/
func (f *federatingActor) PostInbox(c context.Context, w http.ResponseWriter, r *http.Request) (bool, error) {
return f.PostInboxScheme(c, w, r, "https")
}
func (f *federatingActor) Send(c context.Context, outbox *url.URL, t vocab.Type) (pub.Activity, error) {
log.Infof(c, "send activity %s via outbox %s", t.GetTypeName(), outbox)
return f.wrapped.Send(c, outbox, t)
}
func (f *federatingActor) GetInbox(c context.Context, w http.ResponseWriter, r *http.Request) (bool, error) {
return f.wrapped.GetInbox(c, w, r)
}
func (f *federatingActor) PostOutbox(c context.Context, w http.ResponseWriter, r *http.Request) (bool, error) {
return f.wrapped.PostOutbox(c, w, r)
}
func (f *federatingActor) PostOutboxScheme(c context.Context, w http.ResponseWriter, r *http.Request, scheme string) (bool, error) {
return f.wrapped.PostOutboxScheme(c, w, r, scheme)
}
func (f *federatingActor) GetOutbox(c context.Context, w http.ResponseWriter, r *http.Request) (bool, error) {
return f.wrapped.GetOutbox(c, w, r)
}