Adding tarfile member sanitization to extractall()

zipdist/zip.py

@@ -353,7 +353,26 @@ def _extract_tarfile(self, dest_tar = None, verbose = True):
 
         """
         with tarfile.open(dest_tar , "r:gz") as tar:
-            tar.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)
             if verbose: 
                 contents = tar.getnames()
                 sys.stdout.write(f"\tContents of {dest_tar} :\n\t\t")

zipdist/zip2.py

@@ -374,7 +374,26 @@ def _extract_tarfile(self, dest_tar = None, verbose = True):
 
         """
         with tarfile.open(dest_tar , "r:gz") as tar:
-            tar.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)
             if verbose: 
                 contents = tar.getnames()
                 sys.stdout.write(f"\tContents of {dest_tar} :\n\t\t")