Bug#863301: vcmi: removing a mod can recursively delete $HOME

[Johannes Schauer]

Source: vcmi
Severity: critical
Tags: patch
Justification: causes serious data loss

Under the right circumstances, removing a mod can recursively remove
$HOME. For more details see the upstream bugs:

http://bugs.vcmi.eu/view.php?id=2673

http://bugs.vcmi.eu/view.php?id=2680

Patch is attached.
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>From 5d8e943787666543df6b858c001ab4e59b09fe2d Mon Sep 17 00:00:00 2001
From: Arseniy Shestakov <me at arseniyshestakov.com>
Date: Thu, 25 May 2017 03:03:02 +0300
Subject: [PATCH] Launcher: add sanity checks for QDir::removeRecursively.
 Issue 2673

I'm not always fail to uninstall mod, but when I do I remove $HOME
Bumblebee developers should be proud of us...
---
 launcher/modManager/cmodmanager.cpp | 22 ++++++++++++++++++++--
 launcher/modManager/cmodmanager.h   |  1 +
 2 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/launcher/modManager/cmodmanager.cpp b/launcher/modManager/cmodmanager.cpp
index 59fd7faf..99a3df32 100644
--- a/launcher/modManager/cmodmanager.cpp
+++ b/launcher/modManager/cmodmanager.cpp
@@ -245,7 +245,7 @@ bool CModManager::doInstallMod(QString modname, QString archivePath)
 
 	if (!ZipArchive::extract(qstringToPath(archivePath), qstringToPath(destDir)))
 	{
-		QDir(destDir + modDirName).removeRecursively();
+		removeModDir(destDir + modDirName);
 		return addError(modname, "Failed to extract mod data");
 	}
 
@@ -270,7 +270,7 @@ bool CModManager::doUninstallMod(QString modname)
 	if (!localMods.contains(modname))
 		return addError(modname, "Data with this mod was not found");
 
-	if (!QDir(modDir).removeRecursively())
+	if (!removeModDir(modDir))
 		return addError(modname, "Failed to delete mod data");
 
 	localMods.remove(modname);
@@ -279,3 +279,21 @@ bool CModManager::doUninstallMod(QString modname)
 
 	return true;
 }
+
+bool CModManager::removeModDir(QString path)
+{
+	// issues 2673 and 2680 its why you do not recursively remove without sanity check
+	QDir checkDir(path);
+	if(!checkDir.cdUp() || QString::compare("Mods", checkDir.dirName(), Qt::CaseInsensitive))
+		return false;
+	if(!checkDir.cdUp() || QString::compare("vcmi", checkDir.dirName(), Qt::CaseInsensitive))
+		return false;
+
+	QDir dir(path);
+	if(!dir.absolutePath().contains("vcmi", Qt::CaseInsensitive))
+		return false;
+	if(!dir.absolutePath().contains("Mods", Qt::CaseInsensitive))
+		return false;
+
+	return dir.removeRecursively();
+}
diff --git a/launcher/modManager/cmodmanager.h b/launcher/modManager/cmodmanager.h
index 800db6b5..b759ef06 100644
--- a/launcher/modManager/cmodmanager.h
+++ b/launcher/modManager/cmodmanager.h
@@ -18,6 +18,7 @@ class CModManager
 
 	QStringList recentErrors;
 	bool addError(QString modname, QString message);
+	bool removeModDir(QString mod);
 public:
 	CModManager(CModList * modList);
 
-- 
2.11.0