Merge pull request #176 from TrellixVulnTeam/master

CVE-2007-4559 Patch

kb_python/ref.py

@@ -341,7 +341,26 @@ def download_reference(
 
         logger.info('Extracting files from {}'.format(local_path))
         with tarfile.open(local_path, 'r:gz') as f:
-            f.extractall(temp_dir)
+            def is_within_directory(directory, target):
+
+                abs_directory = os.path.abspath(directory)
+                abs_target = os.path.abspath(target)
+
+                prefix = os.path.commonprefix([abs_directory, abs_target])
+
+                return prefix == abs_directory
+
+            def safe_extract(tar, path=".", members=None, *, numeric_owner=False):
+
+                for member in tar.getmembers():
+                    member_path = os.path.join(path, member.name)
+                    if not is_within_directory(path, member_path):
+                        raise Exception("Attempted Path Traversal in Tar File")
+
+                tar.extractall(path, members, numeric_owner=numeric_owner) 
+
+
+            safe_extract(f, temp_dir)
 
         for option in reference.files:
             os.rename(