ActivityPubでリモートのオブジェクトをGETするときのリクエストをHTTP Signatureで署名するオプション (#6731)

* Sign ActivityPub GET

* Fix v12, v12.48.0 UI bug

src/remote/activitypub/request.ts

@@ -1,3 +1,4 @@
+import * as http from 'http';
 import * as https from 'https';
 import { sign } from 'http-signature';
 import * as crypto from 'crypto';
@@ -7,6 +8,9 @@ import { ILocalUser } from '../../models/entities/user';
 import { UserKeypairs } from '../../models';
 import { ensure } from '../../prelude/ensure';
 import { getAgentByUrl } from '../../misc/fetch';
+import { URL } from 'url';
+import got from 'got';
+import * as Got from 'got';
 
 export default async (user: ILocalUser, url: string, object: any) => {
 	const timeout = 10 * 1000;
@@ -62,3 +66,96 @@ export default async (user: ILocalUser, url: string, object: any) => {
 		req.end(data);
 	});
 };
+
+/**
+ * Get AP object with http-signature
+ * @param user http-signature user
+ * @param url URL to fetch
+ */
+export async function signedGet(url: string, user: ILocalUser) {
+	const timeout = 10 * 1000;
+
+	const keypair = await UserKeypairs.findOne({
+		userId: user.id
+	}).then(ensure);
+
+	const req = got.get<any>(url, {
+		headers: {
+			'Accept': 'application/activity+json, application/ld+json',
+			'User-Agent': config.userAgent,
+		},
+		responseType: 'json',
+		timeout,
+		hooks: {
+			beforeRequest: [
+				options => {
+					options.request = (url: URL, opt: http.RequestOptions, callback?: (response: any) => void) => {
+						// Select custom agent by URL
+						opt.agent = getAgentByUrl(url, false);
+
+						// Wrap original https?.request
+						const requestFunc = url.protocol === 'http:' ? http.request : https.request;
+						const clientRequest = requestFunc(url, opt, callback) as http.ClientRequest;
+
+						// HTTP-Signature
+						sign(clientRequest, {
+							authorizationHeaderName: 'Signature',
+							key: keypair.privateKey,
+							keyId: `${config.url}/users/${user.id}#main-key`,
+							headers: ['(request-target)', 'host', 'date', 'accept']
+						});
+
+						return clientRequest;
+					};
+				},
+			],
+		},
+		retry: 0,
+	});
+
+	const res = await receiveResponce(req, 10 * 1024 * 1024);
+
+	return res.body;
+}
+
+/**
+ * Receive response (with size limit)
+ * @param req Request
+ * @param maxSize size limit
+ */
+export async function receiveResponce<T>(req: Got.CancelableRequest<Got.Response<T>>, maxSize: number) {
+	// 応答ヘッダでサイズチェック
+	req.on('response', (res: Got.Response) => {
+		const contentLength = res.headers['content-length'];
+		if (contentLength != null) {
+			const size = Number(contentLength);
+			if (size > maxSize) {
+				req.cancel();
+			}
+		}
+	});
+
+	// 受信中のデータでサイズチェック
+	req.on('downloadProgress', (progress: Got.Progress) => {
+		if (progress.transferred > maxSize) {
+			req.cancel();
+		}
+	});
+
+	// 応答取得 with ステータスコードエラーの整形
+	const res = await req.catch(e => {
+		if (e.name === 'HTTPError') {
+			const statusCode = (e as Got.HTTPError).response.statusCode;
+			const statusMessage = (e as Got.HTTPError).response.statusMessage;
+			throw {
+				name: `StatusError`,
+				statusCode,
+				message: `${statusCode} ${statusMessage}`,
+			};
+		} else {
+			throw e;
+		}
+	});
+
+	return res;
+}

src/remote/activitypub/resolver.ts

@@ -1,8 +1,13 @@
+import config from '../../config';
 import { getJson } from '../../misc/fetch';
+import { ILocalUser } from '../../models/entities/user';
+import { getInstanceActor } from '../../services/instance-actor';
+import { signedGet } from './request';
 import { IObject, isCollectionOrOrderedCollection, ICollection, IOrderedCollection } from './type';
 
 export default class Resolver {
 	private history: Set<string>;
+	private user?: ILocalUser;
 
 	constructor() {
 		this.history = new Set();
@@ -39,7 +44,13 @@ export default class Resolver {
 
 		this.history.add(value);
 
-		const object = await getJson(value, 'application/activity+json, application/ld+json');
+		if (config.signToActivityPubGet && !this.user) {
+			this.user = await getInstanceActor();
+		}
+
+		const object = this.user
+			? await signedGet(value, this.user)
+			: await getJson(value, 'application/activity+json, application/ld+json');
 
 		if (object == null || (
 			Array.isArray(object['@context']) ?