From afb63049798dd0277cd9045eb00a16ab1228376b Mon Sep 17 00:00:00 2001
From: Johann150 <johann.galle@protonmail.com>
Date: Thu, 10 Feb 2022 11:47:46 +0100
Subject: fix: regular expressions in word mutes (#8254)

* fix: handle regex exceptions for word mutes

* add i18n strings

Co-authored-by: rinsuki <428rinsuki+git@gmail.com>

* stricter input validation in backend

* add migration for hard mutes

* fix

* use correct regex library in migration

* use query builder to avoid SQL injection

Co-authored-by: Robin B <robflop98@outlook.com>
Co-authored-by: rinsuki <428rinsuki+git@gmail.com>
---
 packages/backend/src/misc/check-word-mute.ts       | 31 +++++++++++++---------
 .../backend/src/server/api/endpoints/i/update.ts   | 21 ++++++++++++++-
 2 files changed, 38 insertions(+), 14 deletions(-)

(limited to 'packages/backend/src')

diff --git a/packages/backend/src/misc/check-word-mute.ts b/packages/backend/src/misc/check-word-mute.ts
index e2e871dd2b..dedda3cdf6 100644
--- a/packages/backend/src/misc/check-word-mute.ts
+++ b/packages/backend/src/misc/check-word-mute.ts
@@ -11,26 +11,31 @@ type UserLike = {
 	id: User['id'];
 };
 
-export async function checkWordMute(note: NoteLike, me: UserLike | null | undefined, mutedWords: string[][]): Promise<boolean> {
+export async function checkWordMute(note: NoteLike, me: UserLike | null | undefined, mutedWords: Array<string | string[]>): Promise<boolean> {
 	// 自分自身
 	if (me && (note.userId === me.id)) return false;
 
-	const words = mutedWords
-		// Clean up
-		.map(xs => xs.filter(x => x !== ''))
-		.filter(xs => xs.length > 0);
-
-	if (words.length > 0) {
+	if (mutedWords.length > 0) {
 		if (note.text == null) return false;
 
-		const matched = words.some(and =>
-			and.every(keyword => {
-				const regexp = keyword.match(/^\/(.+)\/(.*)$/);
-				if (regexp) {
+		const matched = mutedWords.some(filter => {
+			if (Array.isArray(filter)) {
+				return filter.every(keyword => note.text!.includes(keyword));
+			} else {
+				// represents RegExp
+				const regexp = filter.match(/^\/(.+)\/(.*)$/);
+
+				// This should never happen due to input sanitisation.
+				if (!regexp) return false;
+
+				try {
 					return new RE2(regexp[1], regexp[2]).test(note.text!);
+				} catch (err) {
+					// This should never happen due to input sanitisation.
+					return false;
 				}
-				return note.text!.includes(keyword);
-			}));
+			}
+		});
 
 		if (matched) return true;
 	}
diff --git a/packages/backend/src/server/api/endpoints/i/update.ts b/packages/backend/src/server/api/endpoints/i/update.ts
index eb57aa2bfc..aec7bbd2e1 100644
--- a/packages/backend/src/server/api/endpoints/i/update.ts
+++ b/packages/backend/src/server/api/endpoints/i/update.ts
@@ -1,3 +1,4 @@
+const RE2 = require('re2');
 import $ from 'cafy';
 import * as mfm from 'mfm-js';
 import { ID } from '@/misc/cafy-id';
@@ -117,7 +118,7 @@ export const meta = {
 		},
 
 		mutedWords: {
-			validator: $.optional.arr($.arr($.str)),
+			validator: $.optional.arr($.either($.arr($.str.min(1)).min(1), $.str)),
 		},
 
 		mutedInstances: {
@@ -163,6 +164,12 @@ export const meta = {
 			code: 'NO_SUCH_PAGE',
 			id: '8e01b590-7eb9-431b-a239-860e086c408e',
 		},
+
+		invalidRegexp: {
+			message: 'Invalid Regular Expression.',
+			code: 'INVALID_REGEXP',
+			id: '0d786918-10df-41cd-8f33-8dec7d9a89a5',
+		}
 	},
 
 	res: {
@@ -191,6 +198,18 @@ export default define(meta, async (ps, _user, token) => {
 	if (ps.avatarId !== undefined) updates.avatarId = ps.avatarId;
 	if (ps.bannerId !== undefined) updates.bannerId = ps.bannerId;
 	if (ps.mutedWords !== undefined) {
+		// validate regular expression syntax
+		ps.mutedWords.filter(x => !Array.isArray(x)).forEach(x => {
+			const regexp = x.match(/^\/(.+)\/(.*)$/);
+			if (!regexp) throw new ApiError(meta.errors.invalidRegexp);
+
+			try {
+				new RE2(regexp[1], regexp[2]);
+			} catch (err) {
+				throw new ApiError(meta.errors.invalidRegexp);
+			}
+		});
+
 		profileUpdates.mutedWords = ps.mutedWords;
 		profileUpdates.enableWordMute = ps.mutedWords.length > 0;
 	}
-- 
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