From 0bdd8e0b0516555c6233fdc7901e9b417cf89791 Mon Sep 17 00:00:00 2001
From: Emmanuel Pescosta <[email protected]>
Date: Sun, 19 Feb 2017 02:32:48 +0100
Subject: Disallow executing Dolphin as root on Linux
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Basically a copy of commit kate/9adcebd3c2e476c8a32e9b455cc99f46b0e12a7e which was
written by Martin Grässlin.
---
 src/main.cpp | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/src/main.cpp b/src/main.cpp
index acba8da..789a529 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -35,8 +35,21 @@
 #include <KLocalizedString>
 #include <Kdelibs4ConfigMigrator>
 
+#ifndef Q_OS_WIN
+#include <unistd.h>
+#endif
+#include <iostream>
+
 extern "C" Q_DECL_EXPORT int kdemain(int argc, char **argv)
 {
+#ifndef Q_OS_WIN
+    // Check whether we are running as root
+    if (getuid() == 0) {
+        std::cout << "Executing Dolphin as root is not possible." << std::endl;
+        return EXIT_FAILURE;
+    }
+#endif
+
     QApplication app(argc, argv);
     app.setAttribute(Qt::AA_UseHighDpiPixmaps, true);
     app.setWindowIcon(QIcon::fromTheme(QStringLiteral("system-file-manager"), app.windowIcon()));
-- 
cgit v0.11.2

From 9adcebd3c2e476c8a32e9b455cc99f46b0e12a7e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Gr=C3=A4=C3=9Flin?= <[email protected]>
Date: Thu, 16 Feb 2017 18:00:09 +0100
Subject: Disallow executing kate and kwrite as root on Linux

Summary:
Running GUI applications as root is a huge security risk. Especially
the X server is not secured for that. Non-root applications can easily
interact with a root running application and thus try to exploit simple
bugs in either kate/kwrite itself or in the underlying libraries such
as Qt, XLib or xcb.

In addition kate can be abused to just open the konsole window and any
command can be entered using the XTest extension. This was demonstrated
for dolphin in [1]. The application itself cannot do anything to protect
against it.

On Wayland the situation can be considered worse as the compositor is
running as the normal user and is not protected to handle root windows.
It can be rather trivial to attack the root running application from the
compositor through interfaces such as scripting. This is not in the aim
of the compositors to protect against.

The common use case why users start editors as root is to edit root
owned files. This is a valid use case, but there is no need to run the
application as root. Instead one can use sudoedit to run the application
as user and still be able to edit as root.

This change introduces a check whether the application is started as
root before any interaction with X or Wayland happens, that is prior to
creating the QApplication. If it is detected that we run as root, we
exit and print an information about how to properly edit an application
in kwrite/kate as root. The text is deliberatly not translated to keep
the threat from running as root as low as possible.

The output is:
martin@martin-desktop: ~ $ sudo /opt/kf5/bin/kate
Executing Kate as root is not possible. To edit files as root use:
SUDO_EDITOR=kate sudoedit <file>
martin@martin-desktop: ~ $ sudo /opt/kf5/bin/kwrite
Executing Kate as root is not possible. To edit files as root use:
SUDO_EDITOR=kwrite sudoedit <file>

[1] http://git.net/ml/kwrite-devel/2016-01/msg00011.html

Test Plan: See output

Reviewers: #kate

Subscribers: kwrite-devel

Differential Revision: https://phabricator.kde.org/D4634
---
 kate/main.cpp   | 15 +++++++++++++++
 kwrite/main.cpp | 15 +++++++++++++++
 2 files changed, 30 insertions(+)

diff --git a/kate/main.cpp b/kate/main.cpp
index 5895bee..9fcda33 100644
--- a/kate/main.cpp
+++ b/kate/main.cpp
@@ -51,9 +51,24 @@
 #include "qtsingleapplication/qtsingleapplication.h"
 #endif
 
+#ifndef Q_OS_WIN
+#include <unistd.h>
+#endif
+#include <iostream>
+
 
 int main(int argc, char **argv)
 {
+#ifndef Q_OS_WIN
+    /**
+     * Check whether we are running as root
+     **/
+    if (getuid() == 0) {
+        std::cout << "Executing Kate as root is not possible. To edit files as root use:" << std::endl;
+        std::cout << "SUDO_EDITOR=kate sudoedit <file>" << std::endl;
+        return 0;
+    }
+#endif
     /**
      * init resources from our static lib
      */
diff --git a/kwrite/main.cpp b/kwrite/main.cpp
index a8ed025..4787fed 100644
--- a/kwrite/main.cpp
+++ b/kwrite/main.cpp
@@ -42,8 +42,23 @@
 
 #include "../urlinfo.h"
 
+#ifndef Q_OS_WIN
+#include <unistd.h>
+#endif
+#include <iostream>
+
 extern "C" Q_DECL_EXPORT int main(int argc, char **argv)
 {
+#ifndef Q_OS_WIN
+    /**
+     * Check whether we are running as root
+     **/
+    if (getuid() == 0) {
+        std::cout << "Executing Kwrite as root is not possible. To edit files as root use:" << std::endl;
+        std::cout << "SUDO_EDITOR=kwrite sudoedit <file>" << std::endl;
+        return 0;
+    }
+#endif
     /**
      * Create application first
      * Enforce application name even if the executable is renamed
-- 
cgit v0.11.2