From 8bf8c5ef07b0ac5e914d752681e470dea403a5bd Mon Sep 17 00:00:00 2001
From: Fabian Vogt <fabian@ritter-vogt.de>
Date: Tue, 25 Aug 2020 22:14:37 +0200
Subject: [PATCH] Pass the ARCHIVE_EXTRACT_SECURE_SYMLINKS flag to libarchive

There are archive types which allow to first create a symlink and then
later on dereference it. If the symlink points outside of the archive,
this results in writing outside of the destination directory.

With the ARCHIVE_EXTRACT_SECURE_SYMLINKS option set, libarchive avoids
this situation by verifying that none of the target path components are
symlinks before writing.

Remove the commented out code in the method, which would actually
misbehave if enabled again.

Signed-off-by: Fabian Vogt <fabian@ritter-vogt.de>
---
 plugins/libarchive/libarchiveplugin.cpp | 18 +++---------------
 1 file changed, 3 insertions(+), 15 deletions(-)

diff --git a/plugins/libarchive/libarchiveplugin.cpp b/plugins/libarchive/libarchiveplugin.cpp
index 50e81da1..8a0fed21 100644
--- a/plugins/libarchive/libarchiveplugin.cpp
+++ b/plugins/libarchive/libarchiveplugin.cpp
@@ -509,21 +509,9 @@ void LibarchivePlugin::emitEntryFromArchiveEntry(struct archive_entry *aentry)
 
 int LibarchivePlugin::extractionFlags() const
 {
-    int result = ARCHIVE_EXTRACT_TIME;
-    result |= ARCHIVE_EXTRACT_SECURE_NODOTDOT;
-
-    // TODO: Don't use arksettings here
-    /*if ( ArkSettings::preservePerms() )
-    {
-        result &= ARCHIVE_EXTRACT_PERM;
-    }
-
-    if ( !ArkSettings::extractOverwrite() )
-    {
-        result &= ARCHIVE_EXTRACT_NO_OVERWRITE;
-    }*/
-
-    return result;
+    return ARCHIVE_EXTRACT_TIME
+           | ARCHIVE_EXTRACT_SECURE_NODOTDOT
+           | ARCHIVE_EXTRACT_SECURE_SYMLINKS;
 }
 
 void LibarchivePlugin::copyData(const QString& filename, struct archive *dest, bool partialprogress)
-- 
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