Merge pull request #897 from TrellixVulnTeam/master

CVE-2007-4559 Patch

contrib/nydus-test/framework/nydusify.py

@@ -276,7 +276,26 @@ def pull_bootstrap(self, downloaded_dir, bootstrap_name, arch="amd64"):
             with open("image.gzip", "wb") as w:
                 shutil.copyfileobj(reader.raw, w)
             with tarfile.open("image.gzip", "r:gz") as tar_gz:
-                tar_gz.extractall()
+                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(tar_gz)
                 os.rename("image/image.boot", bootstrap_name)
             os.remove("image.gzip")