Mark device list as stale, if we don't have the requesting device (#2728)

This hopefully makes E2EE chats a little bit more reliable by re-syncing
devices if we don't have the `requesting_device_id` in our database. (As
seen in
[Synapse](https://github.com/matrix-org/synapse/blob/c52abc1cfdd9e5480cdb4a03d626fe61cacc6573/synapse/handlers/devicemessage.py#L157-L201))

4 files changed, 46 insertions, 6 deletions

diff --git a/keyserver/api/api.go b/keyserver/api/api.go
index 9ba3988b..c9ec59a7 100644
--- a/keyserver/api/api.go
+++ b/keyserver/api/api.go
@@ -21,9 +21,10 @@ import (
 	"strings"
 	"time"
 
+	"github.com/matrix-org/gomatrixserverlib"
+
 	"github.com/matrix-org/dendrite/keyserver/types"
 	userapi "github.com/matrix-org/dendrite/userapi/api"
-	"github.com/matrix-org/gomatrixserverlib"
 )
 
 type KeyInternalAPI interface {
@@ -56,6 +57,7 @@ type UserKeyAPI interface {
 type SyncKeyAPI interface {
 	QueryKeyChanges(ctx context.Context, req *QueryKeyChangesRequest, res *QueryKeyChangesResponse) error
 	QueryOneTimeKeys(ctx context.Context, req *QueryOneTimeKeysRequest, res *QueryOneTimeKeysResponse) error
+	PerformMarkAsStaleIfNeeded(ctx context.Context, req *PerformMarkAsStaleRequest, res *struct{}) error
 }
 
 type FederationKeyAPI interface {
@@ -335,3 +337,9 @@ type QuerySignaturesResponse struct {
 	// The request error, if any
 	Error *KeyError
 }
+
+type PerformMarkAsStaleRequest struct {
+	UserID   string
+	Domain   gomatrixserverlib.ServerName
+	DeviceID string
+}
diff --git a/keyserver/internal/internal.go b/keyserver/internal/internal.go
index 41b4d44a..a8d1128c 100644
--- a/keyserver/internal/internal.go
+++ b/keyserver/internal/internal.go
@@ -23,16 +23,17 @@ import (
 	"sync"
 	"time"
 
-	fedsenderapi "github.com/matrix-org/dendrite/federationapi/api"
-	"github.com/matrix-org/dendrite/keyserver/api"
-	"github.com/matrix-org/dendrite/keyserver/producers"
-	"github.com/matrix-org/dendrite/keyserver/storage"
-	userapi "github.com/matrix-org/dendrite/userapi/api"
 	"github.com/matrix-org/gomatrixserverlib"
 	"github.com/matrix-org/util"
 	"github.com/sirupsen/logrus"
 	"github.com/tidwall/gjson"
 	"github.com/tidwall/sjson"
+
+	fedsenderapi "github.com/matrix-org/dendrite/federationapi/api"
+	"github.com/matrix-org/dendrite/keyserver/api"
+	"github.com/matrix-org/dendrite/keyserver/producers"
+	"github.com/matrix-org/dendrite/keyserver/storage"
+	userapi "github.com/matrix-org/dendrite/userapi/api"
 )
 
 type KeyInternalAPI struct {
@@ -224,6 +225,19 @@ func (a *KeyInternalAPI) QueryDeviceMessages(ctx context.Context, req *api.Query
 	return nil
 }
 
+// PerformMarkAsStaleIfNeeded marks the users device list as stale, if the given deviceID is not present
+// in our database.
+func (a *KeyInternalAPI) PerformMarkAsStaleIfNeeded(ctx context.Context, req *api.PerformMarkAsStaleRequest, res *struct{}) error {
+	knownDevices, err := a.DB.DeviceKeysForUser(ctx, req.UserID, []string{req.DeviceID}, true)
+	if err != nil {
+		return err
+	}
+	if len(knownDevices) == 0 {
+		return a.Updater.ManualUpdate(ctx, req.Domain, req.UserID)
+	}
+	return nil
+}
+
 // nolint:gocyclo
 func (a *KeyInternalAPI) QueryKeys(ctx context.Context, req *api.QueryKeysRequest, res *api.QueryKeysResponse) error {
 	res.DeviceKeys = make(map[string]map[string]json.RawMessage)
diff --git a/keyserver/inthttp/client.go b/keyserver/inthttp/client.go
index 7a713114..75d537d9 100644
--- a/keyserver/inthttp/client.go
+++ b/keyserver/inthttp/client.go
@@ -37,6 +37,7 @@ const (
 	QueryOneTimeKeysPath              = "/keyserver/queryOneTimeKeys"
 	QueryDeviceMessagesPath           = "/keyserver/queryDeviceMessages"
 	QuerySignaturesPath               = "/keyserver/querySignatures"
+	PerformMarkAsStalePath            = "/keyserver/markAsStale"
 )
 
 // NewKeyServerClient creates a KeyInternalAPI implemented by talking to a HTTP POST API.
@@ -172,3 +173,14 @@ func (h *httpKeyInternalAPI) QuerySignatures(
 		h.httpClient, ctx, request, response,
 	)
 }
+
+func (h *httpKeyInternalAPI) PerformMarkAsStaleIfNeeded(
+	ctx context.Context,
+	request *api.PerformMarkAsStaleRequest,
+	response *struct{},
+) error {
+	return httputil.CallInternalRPCAPI(
+		"MarkAsStale", h.apiURL+PerformMarkAsStalePath,
+		h.httpClient, ctx, request, response,
+	)
+}
diff --git a/keyserver/inthttp/server.go b/keyserver/inthttp/server.go
index 4e5f9fba..7af0ff6e 100644
--- a/keyserver/inthttp/server.go
+++ b/keyserver/inthttp/server.go
@@ -16,6 +16,7 @@ package inthttp
 
 import (
 	"github.com/gorilla/mux"
+
 	"github.com/matrix-org/dendrite/internal/httputil"
 	"github.com/matrix-org/dendrite/keyserver/api"
 )
@@ -70,4 +71,9 @@ func AddRoutes(internalAPIMux *mux.Router, s api.KeyInternalAPI) {
 		QuerySignaturesPath,
 		httputil.MakeInternalRPCAPI("KeyserverQuerySignatures", s.QuerySignatures),
 	)
+
+	internalAPIMux.Handle(
+		PerformMarkAsStalePath,
+		httputil.MakeInternalRPCAPI("KeyserverMarkAsStale", s.PerformMarkAsStaleIfNeeded),
+	)
 }