diff options
| -rw-r--r-- | Doc/library/urllib.parse.rst | 13 | ||||
| -rw-r--r-- | Lib/test/test_urlparse.py | 29 | ||||
| -rw-r--r-- | Lib/urllib/parse.py | 6 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Security/2021-04-25-07-46-37.bpo-43882.Jpwx85.rst | 6 |
4 files changed, 54 insertions, 0 deletions
diff --git a/Doc/library/urllib.parse.rst b/Doc/library/urllib.parse.rst index 67c2120..0aaac56 100644 --- a/Doc/library/urllib.parse.rst +++ b/Doc/library/urllib.parse.rst @@ -312,6 +312,9 @@ or on combining URL components into a URL string. ``#``, ``@``, or ``:`` will raise a :exc:`ValueError`. If the URL is decomposed before parsing, no error will be raised. + Following the `WHATWG spec`_ that updates RFC 3986, ASCII newline + ``\n``, ``\r`` and tab ``\t`` characters are stripped from the URL. + .. versionchanged:: 3.6 Out-of-range port numbers now raise :exc:`ValueError`, instead of returning :const:`None`. @@ -320,6 +323,10 @@ or on combining URL components into a URL string. Characters that affect netloc parsing under NFKC normalization will now raise :exc:`ValueError`. + .. versionchanged:: 3.10 + ASCII newline and tab characters are stripped from the URL. + +.. _WHATWG spec: https://url.spec.whatwg.org/#concept-basic-url-parser .. function:: urlunsplit(parts) @@ -674,6 +681,10 @@ task isn't already covered by the URL parsing functions above. .. seealso:: + `WHATWG`_ - URL Living standard + Working Group for the URL Standard that defines URLs, domains, IP addresses, the + application/x-www-form-urlencoded format, and their API. + :rfc:`3986` - Uniform Resource Identifiers This is the current standard (STD66). Any changes to urllib.parse module should conform to this. Certain deviations could be observed, which are @@ -697,3 +708,5 @@ task isn't already covered by the URL parsing functions above. :rfc:`1738` - Uniform Resource Locators (URL) This specifies the formal syntax and semantics of absolute URLs. + +.. _WHATWG: https://url.spec.whatwg.org/ diff --git a/Lib/test/test_urlparse.py b/Lib/test/test_urlparse.py index c543ac9..67341fe 100644 --- a/Lib/test/test_urlparse.py +++ b/Lib/test/test_urlparse.py @@ -612,6 +612,35 @@ class UrlParseTestCase(unittest.TestCase): with self.assertRaisesRegex(ValueError, "out of range"): p.port + def test_urlsplit_remove_unsafe_bytes(self): + # Remove ASCII tabs and newlines from input + url = "http://www.python.org/java\nscript:\talert('msg\r\n')/#frag" + p = urllib.parse.urlsplit(url) + self.assertEqual(p.scheme, "http") + self.assertEqual(p.netloc, "www.python.org") + self.assertEqual(p.path, "/javascript:alert('msg')/") + self.assertEqual(p.query, "") + self.assertEqual(p.fragment, "frag") + self.assertEqual(p.username, None) + self.assertEqual(p.password, None) + self.assertEqual(p.hostname, "www.python.org") + self.assertEqual(p.port, None) + self.assertEqual(p.geturl(), "http://www.python.org/javascript:alert('msg')/#frag") + + # Remove ASCII tabs and newlines from input as bytes. + url = b"http://www.python.org/java\nscript:\talert('msg\r\n')/#frag" + p = urllib.parse.urlsplit(url) + self.assertEqual(p.scheme, b"http") + self.assertEqual(p.netloc, b"www.python.org") + self.assertEqual(p.path, b"/javascript:alert('msg')/") + self.assertEqual(p.query, b"") + self.assertEqual(p.fragment, b"frag") + self.assertEqual(p.username, None) + self.assertEqual(p.password, None) + self.assertEqual(p.hostname, b"www.python.org") + self.assertEqual(p.port, None) + self.assertEqual(p.geturl(), b"http://www.python.org/javascript:alert('msg')/#frag") + def test_attributes_bad_port(self): """Check handling of invalid ports.""" for bytes in (False, True): diff --git a/Lib/urllib/parse.py b/Lib/urllib/parse.py index 21cae47..c11c695 100644 --- a/Lib/urllib/parse.py +++ b/Lib/urllib/parse.py @@ -78,6 +78,9 @@ scheme_chars = ('abcdefghijklmnopqrstuvwxyz' '0123456789' '+-.') +# Unsafe bytes to be removed per WHATWG spec +_UNSAFE_URL_BYTES_TO_REMOVE = ['\t', '\r', '\n'] + # XXX: Consider replacing with functools.lru_cache MAX_CACHE_SIZE = 20 _parse_cache = {} @@ -469,6 +472,9 @@ def urlsplit(url, scheme='', allow_fragments=True): else: scheme, url = url[:i].lower(), url[i+1:] + for b in _UNSAFE_URL_BYTES_TO_REMOVE: + url = url.replace(b, "") + if url[:2] == '//': netloc, url = _splitnetloc(url, 2) if (('[' in netloc and ']' not in netloc) or diff --git a/Misc/NEWS.d/next/Security/2021-04-25-07-46-37.bpo-43882.Jpwx85.rst b/Misc/NEWS.d/next/Security/2021-04-25-07-46-37.bpo-43882.Jpwx85.rst new file mode 100644 index 0000000..a326d07 --- /dev/null +++ b/Misc/NEWS.d/next/Security/2021-04-25-07-46-37.bpo-43882.Jpwx85.rst @@ -0,0 +1,6 @@ +The presence of newline or tab characters in parts of a URL could allow +some forms of attacks. + +Following the controlling specification for URLs defined by WHATWG +:func:`urllib.parse` now removes ASCII newlines and tabs from URLs, +preventing such attacks. |