Add m.direct filter / validation (#10436)

src/utils/DMRoomMap.ts

@@ -23,6 +23,7 @@ import { MatrixEvent } from "matrix-js-sdk/src/models/event";
 import { Optional } from "matrix-events-sdk";
 
 import { MatrixClientPeg } from "../MatrixClientPeg";
+import { filterValidMDirect } from "./dm/filterValidMDirect";
 
 /**
  * Class that takes a Matrix Client and flips the m.direct map
@@ -44,8 +45,8 @@ export default class DMRoomMap {
         // see onAccountData
         this.hasSentOutPatchDirectAccountDataPatch = false;
 
-        const mDirectEvent = matrixClient.getAccountData(EventType.Direct)?.getContent() ?? {};
-        this.mDirectEvent = { ...mDirectEvent }; // copy as we will mutate
+        const mDirectRawContent = matrixClient.getAccountData(EventType.Direct)?.getContent() ?? {};
+        this.setMDirectFromContent(mDirectRawContent);
     }
 
     /**
@@ -84,9 +85,28 @@ export default class DMRoomMap {
         this.matrixClient.removeListener(ClientEvent.AccountData, this.onAccountData);
     }
 
+    /**
+     * Filter m.direct content to contain only valid data and then sets it.
+     * Logs if invalid m.direct content occurs.
+     * {@link filterValidMDirect}
+     *
+     * @param content - Raw m.direct content
+     */
+    private setMDirectFromContent(content: unknown): void {
+        const { valid, filteredContent } = filterValidMDirect(content);
+
+        if (!valid) {
+            logger.warn("Invalid m.direct content occurred", content);
+        }
+
+        this.mDirectEvent = filteredContent;
+    }
+
     private onAccountData = (ev: MatrixEvent): void => {
+        console.log("onAccountData");
+
         if (ev.getType() == EventType.Direct) {
-            this.mDirectEvent = { ...ev.getContent() }; // copy as we will mutate
+            this.setMDirectFromContent(ev.getContent());
             this.userToRooms = null;
             this.roomToUser = null;
         }

src/utils/dm/filterValidMDirect.ts

@@ -0,0 +1,69 @@
+/*
+Copyright 2023 The Matrix.org Foundation C.I.C.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+interface FilterValidMDirectResult {
+    /** Whether the entire content is valid */
+    valid: boolean;
+    /** Filtered content with only the valid parts */
+    filteredContent: Record<string, string[]>;
+}
+
+/**
+ * Filter m.direct content to be compliant to https://spec.matrix.org/v1.6/client-server-api/#mdirect.
+ *
+ * @param content - Raw event content to be filerted
+ * @returns value as a flag whether to content was valid.
+ *          filteredContent with only values from the content that are spec compliant.
+ */
+export const filterValidMDirect = (content: unknown): FilterValidMDirectResult => {
+    if (content === null || typeof content !== "object") {
+        return {
+            valid: false,
+            filteredContent: {},
+        };
+    }
+
+    const filteredContent = new Map();
+    let valid = true;
+
+    for (const [userId, roomIds] of Object.entries(content)) {
+        if (typeof userId !== "string") {
+            valid = false;
+            continue;
+        }
+
+        if (!Array.isArray(roomIds)) {
+            valid = false;
+            continue;
+        }
+
+        const filteredRoomIds: string[] = [];
+        filteredContent.set(userId, filteredRoomIds);
+
+        for (const roomId of roomIds) {
+            if (typeof roomId === "string") {
+                filteredRoomIds.push(roomId);
+            } else {
+                valid = false;
+            }
+        }
+    }
+
+    return {
+        valid,
+        filteredContent: Object.fromEntries(filteredContent.entries()),
+    };
+};