Adding tarfile member sanitization to extractall()

Author: PatchTester

update-gyp.py

@@ -33,7 +33,25 @@
 
         print("Unzipping...")
         with tarfile.open(tar_file, "r:gz") as tar_ref:
-            tar_ref.extractall(unzip_target)
+            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)
+
+            safe_extract(tar_ref, unzip_target)
 
         print("Moving to current checkout (" + CHECKOUT_PATH + ")...")
         if os.path.exists(CHECKOUT_GYP_PATH):