1 /*
2 KWin - the KDE window manager
3 This file is part of the KDE project.
4
5 SPDX-FileCopyrightText: 2020 Vlad Zahorodnii <vlad.zahorodnii@kde.org>
6 SPDX-FileCopyrightText: 2021 David Edmundson <davidedmundson@kde.org>
7
8 SPDX-License-Identifier: GPL-2.0-or-later
9 */
10
11 #include "xauthority.h"
12
13 #include <QDataStream>
14 #include <QRandomGenerator>
15 #include <QHostInfo>
16 #include <QTemporaryFile>
17 #include <QStandardPaths>
18
writeXauthorityEntry(QDataStream & stream,quint16 family,const QByteArray & address,const QByteArray & display,const QByteArray & name,const QByteArray & cookie)19 static void writeXauthorityEntry(QDataStream &stream, quint16 family,
20 const QByteArray &address, const QByteArray &display,
21 const QByteArray &name, const QByteArray &cookie)
22 {
23 stream << quint16(family);
24
25 auto writeArray = [&stream](const QByteArray &str) {
26 stream << quint16(str.size());
27 stream.writeRawData(str.constData(), str.size());
28 };
29
30 writeArray(address);
31 writeArray(display);
32 writeArray(name);
33 writeArray(cookie);
34 }
35
generateXauthorityCookie()36 static QByteArray generateXauthorityCookie()
37 {
38 QByteArray cookie;
39 cookie.resize(16); // Cookie must be 128bits
40
41 QRandomGenerator *generator = QRandomGenerator::system();
42 for (int i = 0; i < cookie.size(); ++i) {
43 cookie[i] = uint8_t(generator->bounded(256));
44 }
45 return cookie;
46 }
47
generateXauthorityFile(int display,QTemporaryFile * authorityFile)48 bool generateXauthorityFile(int display, QTemporaryFile *authorityFile)
49 {
50 const QString runtimeDirectory = QStandardPaths::writableLocation(QStandardPaths::RuntimeLocation);
51
52 authorityFile->setFileTemplate(runtimeDirectory + QStringLiteral("/xauth_XXXXXX"));
53 if (!authorityFile->open()) {
54 return false;
55 }
56
57 const QByteArray hostname = QHostInfo::localHostName().toUtf8();
58 const QByteArray displayName = QByteArray::number(display);
59 const QByteArray name = QByteArrayLiteral("MIT-MAGIC-COOKIE-1");
60 const QByteArray cookie = generateXauthorityCookie();
61
62 QDataStream stream(authorityFile);
63 stream.setByteOrder(QDataStream::BigEndian);
64
65 // Write entry with FamilyLocal and the host name as address
66 writeXauthorityEntry(stream, 256 /* FamilyLocal */, hostname, displayName, name, cookie);
67
68 // Write entry with FamilyWild, no address
69 writeXauthorityEntry(stream, 65535 /* FamilyWild */, QByteArray{}, displayName, name, cookie);
70
71 if (stream.status() != QDataStream::Ok || !authorityFile->flush()) {
72 authorityFile->remove();
73 return false;
74 }
75
76 return true;
77 }
78