user/kauth: patch CVE-2019-7443 (#213)

1 files changed, 68 insertions, 0 deletions

diff --git a/user/kauth/CVE-2019-7443.patch b/user/kauth/CVE-2019-7443.patch
new file mode 100644
index 000000000..5b11cd8f5
--- /dev/null
+++ b/user/kauth/CVE-2019-7443.patch
@@ -0,0 +1,68 @@
+From fc70fb0161c1b9144d26389434d34dd135cd3f4a Mon Sep 17 00:00:00 2001
+From: Albert Astals Cid <aacid@kde.org>
+Date: Sat, 2 Feb 2019 14:35:25 +0100
+Subject: Remove support for passing gui QVariants to KAuth helpers
+
+Supporting gui variants is very dangerous since they can end up triggering
+image loading plugins which are one of the biggest vectors for crashes, which
+for very smart people mean possible code execution, which is very dangerous
+in code that is executed as root.
+
+We've checked all the KAuth helpers inside KDE git and none seems to be using
+gui variants, so we're not actually limiting anything that people wanted to do.
+
+Reviewed by security@kde.org and Aleix Pol
+
+Issue reported by Fabian Vogt
+---
+ src/backends/dbus/DBusHelperProxy.cpp | 9 +++++++++
+ src/kauthaction.h                     | 2 ++
+ 2 files changed, 11 insertions(+)
+
+diff --git a/src/backends/dbus/DBusHelperProxy.cpp b/src/backends/dbus/DBusHelperProxy.cpp
+index 10c14c6..8f0d336 100644
+--- a/src/backends/dbus/DBusHelperProxy.cpp
++++ b/src/backends/dbus/DBusHelperProxy.cpp
+@@ -31,6 +31,8 @@
+ #include "kf5authadaptor.h"
+ #include "kauthdebug.h"
+ 
++extern Q_CORE_EXPORT const QMetaTypeInterface *qMetaTypeGuiHelper;
++
+ namespace KAuth
+ {
+ 
+@@ -229,10 +231,17 @@ QByteArray DBusHelperProxy::performAction(const QString &action, const QByteArra
+         return ActionReply::HelperBusyReply().serialized();
+     }
+ 
++    // Make sure we don't try restoring gui variants, in particular QImage/QPixmap/QIcon are super dangerous
++    // since they end up calling the image loaders and thus are a vector for crashing → executing code
++    auto origMetaTypeGuiHelper = qMetaTypeGuiHelper;
++    qMetaTypeGuiHelper = nullptr;
++
+     QVariantMap args;
+     QDataStream s(&arguments, QIODevice::ReadOnly);
+     s >> args;
+ 
++    qMetaTypeGuiHelper = origMetaTypeGuiHelper;
++
+     m_currentAction = action;
+     emit remoteSignal(ActionStarted, action, QByteArray());
+     QEventLoop e;
+diff --git a/src/kauthaction.h b/src/kauthaction.h
+index c67a70a..01f3ba1 100644
+--- a/src/kauthaction.h
++++ b/src/kauthaction.h
+@@ -298,6 +298,8 @@ public:
+      * This method sets the variant map that the application
+      * can use to pass arbitrary data to the helper when executing the action.
+      *
++     * Only non-gui variants are supported.
++     *
+      * @param arguments The new arguments map
+      */
+     void setArguments(const QVariantMap &arguments);
+-- 
+cgit v1.1
+