47 lines
1.5 KiB
TypeScript
47 lines
1.5 KiB
TypeScript
// Copyright 2020 Signal Messenger, LLC
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// SPDX-License-Identifier: AGPL-3.0-only
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import * as fs from 'fs';
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import { isWindows } from '../OS';
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const ZONE_IDENTIFIER_CONTENTS = Buffer.from('[ZoneTransfer]\r\nZoneId=3');
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/**
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* Internet Explorer introduced the concept of "Security Zones". For our purposes, we
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* just need to set the security zone to the "Internet" zone, which Windows will use to
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* offer some protections. This is customizable by the user (or, more likely, by IT).
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*
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* To do this, we write the "Zone.Identifier" for the NTFS alternative data stream.
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*
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* This can fail in a bunch of sitations:
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*
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* - The OS is not Windows.
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* - The filesystem is not NTFS.
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* - Writing the metadata file fails for some reason (permissions, for example).
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* - The metadata file already exists. (We could choose to overwrite it.)
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* - The original file is deleted between the time that we check for its existence and
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* when we write the metadata. This is a rare race condition, but is possible.
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*
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* Consumers of this module should probably tolerate failures.
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*/
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export async function writeWindowsZoneIdentifier(
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filePath: string
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): Promise<void> {
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if (!isWindows()) {
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throw new Error('writeWindowsZoneIdentifier should only run on Windows');
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}
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if (!fs.existsSync(filePath)) {
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throw new Error(
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'writeWindowsZoneIdentifier could not find the original file'
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);
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}
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await fs.promises.writeFile(
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`${filePath}:Zone.Identifier`,
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ZONE_IDENTIFIER_CONTENTS,
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{
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flag: 'wx',
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}
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);
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}
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