Adding tarfile member sanitization to extractall()

qa/rpc-tests/upgrade_golden.py

@@ -79,7 +79,26 @@ class UpgradeGoldenTest(BitcoinTestFramework):
                 regtest_path = self.options.tmpdir+"/node"+ str(i)+"/regtest"
                 shutil.rmtree(regtest_path)
                 with tarfile.open(upgrade.tgz_path, "r:gz") as tgz:
-                    tgz.extractall(path = regtest_path)
+                    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(tgz, path=regtest_path)
 
                     # Upgrade each node to the latest network version. If any fails to
                     # start, this will fail the test.