Sanitize notifications ids as they are retransmitted over the TTY

docs/changelog.rst

@@ -56,6 +56,10 @@ Detailed list of changes
 
 - Wayland: Fix remembering window size not accurate when client side decorations are present
 
+- Fix an issue where notification identifiers were not sanitized leading to
+  code execution if the user clicked on a notification popup from a malicious
+  source. Thanks to Carter Sande for discovering this vulnerability.
+
 0.26.1 [2022-08-30]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 

kitty/notify.py

@@ -1,13 +1,15 @@
 #!/usr/bin/env python3
 # License: GPLv3 Copyright: 2019, Kovid Goyal <kovid at kovidgoyal.net>
 
+import re
 from base64 import standard_b64decode
 from collections import OrderedDict
 from itertools import count
-from typing import Dict, Optional, Callable
+from typing import Callable, Dict, Optional
 
 from .constants import is_macos, logo_png_file
 from .fast_data_types import get_boss
+from .types import run_once
 from .utils import log_error
 
 NotifyImplementation = Callable[[str, str, str], None]
@@ -92,6 +94,11 @@ def parse_osc_777(raw: str) -> NotificationCommand:
     return ans
 
 
+@run_once
+def sanitize_identifier_pat() -> 're.Pattern[str]':
+    return re.compile(r'[^a-zA-Z0-9-_+.]+')
+
+
 def parse_osc_99(raw: str) -> NotificationCommand:
     cmd = NotificationCommand()
     metadata, payload = raw.partition(';')[::2]
@@ -107,7 +114,7 @@ def parse_osc_99(raw: str) -> NotificationCommand:
             if k == 'p':
                 payload_type = v
             elif k == 'i':
-                cmd.identifier = v
+                cmd.identifier = sanitize_identifier_pat().sub('', v)
             elif k == 'e':
                 payload_is_encoded = v == '1'
             elif k == 'd':

kitty/window.py

@@ -41,7 +41,7 @@ from .fast_data_types import (
     update_window_title, update_window_visibility, wakeup_main_loop
 )
 from .keys import keyboard_mode_name, mod_mask
-from .notify import NotificationCommand, handle_notification_cmd
+from .notify import NotificationCommand, handle_notification_cmd, sanitize_identifier_pat
 from .options.types import Options
 from .rgb import to_color
 from .terminfo import get_capabilities
@@ -1001,6 +1001,7 @@ class Window:
         self.screen.send_escape_code_to_child(OSC, f'{code};rgb:{r:04x}/{g:04x}/{b:04x}')
 
     def report_notification_activated(self, identifier: str) -> None:
+        identifier = sanitize_identifier_pat().sub('', identifier)
         self.screen.send_escape_code_to_child(OSC, f'99;i={identifier};')
 
     def set_dynamic_color(self, code: int, value: Union[str, bytes]) -> None:

kitty_tests/datatypes.py

@@ -555,3 +555,7 @@ class TestDataTypes(BaseTest):
         self.assertEqual(hash(SingleKey(key=1)), hash(SingleKey(key=1)))
         self.assertNotEqual(hash(SingleKey(key=1, mods=2)), hash(SingleKey(key=1)))
         self.assertNotEqual(SingleKey(key=1, mods=2), SingleKey(key=1))
+
+    def test_notify_identifier_sanitization(self):
+        from kitty.notify import sanitize_identifier_pat
+        self.ae(sanitize_identifier_pat().sub('', '\x1b\nabc\n[*'), 'abc')