pythongh-102153: Start stripping C0 control and space chars in urlsplit

Author: illia-v

Doc/library/urllib.parse.rst

@@ -324,8 +324,9 @@ 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.
+   Following the `WHATWG spec`_ that updates RFC 3986, leading and trailing C0
+   control and space characters are stripped from the URL. ``\n``, ``\r`` and
+   tab ``\t`` characters are removed from the URL at any position.
 
    .. versionchanged:: 3.6
       Out-of-range port numbers now raise :exc:`ValueError`, instead of
@@ -338,6 +339,10 @@ or on combining URL components into a URL string.
    .. versionchanged:: 3.10
       ASCII newline and tab characters are stripped from the URL.
 
+   .. versionchanged:: 3.12
+      Leading and trailing C0 control and space characters are stripped from
+      the URL
+
 .. _WHATWG spec: https://url.spec.whatwg.org/#concept-basic-url-parser
 
 .. function:: urlunsplit(parts)

Lib/test/test_urlparse.py

@@ -649,14 +649,52 @@ def test_urlsplit_remove_unsafe_bytes(self):
             self.assertEqual(p.scheme, "http")
             self.assertEqual(p.geturl(), "http://www.python.org/javascript:alert('msg')/?query=something#fragment")
 
+    def test_urlsplit_strip_url(self):
+        noise = bytes([*range(0, 0x1f), 0x20])
+        base_url = "http://User:[email protected]:080/doc/?query=yes#frag"
+
+        url = noise.decode() + base_url + noise.decode()
+        p = urllib.parse.urlsplit(url)
+        self.assertEqual(p.scheme, "http")
+        self.assertEqual(p.netloc, "User:[email protected]:080")
+        self.assertEqual(p.path, "/doc/")
+        self.assertEqual(p.query, "query=yes")
+        self.assertEqual(p.fragment, "frag")
+        self.assertEqual(p.username, "User")
+        self.assertEqual(p.password, "Pass")
+        self.assertEqual(p.hostname, "www.python.org")
+        self.assertEqual(p.port, 80)
+        self.assertEqual(p.geturl(), base_url)
+
+        url = noise + base_url.encode() + noise
+        p = urllib.parse.urlsplit(url)
+        self.assertEqual(p.scheme, b"http")
+        self.assertEqual(p.netloc, b"User:[email protected]:080")
+        self.assertEqual(p.path, b"/doc/")
+        self.assertEqual(p.query, b"query=yes")
+        self.assertEqual(p.fragment, b"frag")
+        self.assertEqual(p.username, b"User")
+        self.assertEqual(p.password, b"Pass")
+        self.assertEqual(p.hostname, b"www.python.org")
+        self.assertEqual(p.port, 80)
+        self.assertEqual(p.geturl(), base_url.encode())
+
+        # with scheme as cache-key
+        url = "//www.python.org/"
+        scheme = noise.decode() + "https" + noise.decode()
+        for _ in range(2):
+            p = urllib.parse.urlsplit(url, scheme=scheme)
+            self.assertEqual(p.scheme, "https")
+            self.assertEqual(p.geturl(), "https://www.python.org/")
+
     def test_attributes_bad_port(self):
         """Check handling of invalid ports."""
         for bytes in (False, True):
             for parse in (urllib.parse.urlsplit, urllib.parse.urlparse):
                 for port in ("foo", "1.5", "-1", "0x10", "-0", "1_1", " 1", "1 ", "६"):
                     with self.subTest(bytes=bytes, parse=parse, port=port):
                         netloc = "www.example.net:" + port
-                        url = "http://" + netloc
+                        url = "http://" + netloc + "/"
                         if bytes:
                             if netloc.isascii() and port.isascii():
                                 netloc = netloc.encode("ascii")

Lib/urllib/parse.py

@@ -79,6 +79,9 @@
                 '0123456789'
                 '+-.')
 
+# Leading and trailing C0 control and space to be stripped per WHATWG spec
+_URL_CHARS_TO_STRIP = "".join([*(chr(i) for i in range(0, 0x1f + 1)), " "])
+
 # Unsafe bytes to be removed per WHATWG spec
 _UNSAFE_URL_BYTES_TO_REMOVE = ['\t', '\r', '\n']
 
@@ -452,6 +455,8 @@ def urlsplit(url, scheme='', allow_fragments=True):
     """
 
     url, scheme, _coerce_result = _coerce_args(url, scheme)
+    url = url.strip(_URL_CHARS_TO_STRIP)
+    scheme = scheme.strip(_URL_CHARS_TO_STRIP)
 
     for b in _UNSAFE_URL_BYTES_TO_REMOVE:
         url = url.replace(b, "")

Misc/NEWS.d/next/Security/2023-03-07-20-59-17.gh-issue-102153.14CLSZ.rst

@@ -0,0 +1,3 @@
+:func:`urllib.parse.urlsplit` now strips leading and trailing C0 control and
+space characters following the controlling specification for URLs defined by
+WHATWG in response to CVE-2023-24329. Patch by Illia Volochii.