From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Lumir Balhar Date: Thu, 25 May 2023 10:03:57 +0200 Subject: [PATCH] 00399-cve-2023-24329.patch 00399 # * gh-102153: Start stripping C0 control and space chars in `urlsplit` (GH-102508) `urllib.parse.urlsplit` has already been respecting the WHATWG spec a bit GH-25595. This adds more sanitizing to respect the "Remove any leading C0 control or space from input" [rule](https://url.spec.whatwg.org/GH-url-parsing:~:text=Remove%20any%20leading%20and%20trailing%20C0%20control%20or%20space%20from%20input.) in response to [CVE-2023-24329](https://nvd.nist.gov/vuln/detail/CVE-2023-24329). Backported to Python 2 from Python 3.12. Co-authored-by: Illia Volochii Co-authored-by: Gregory P. Smith [Google] Co-authored-by: Lumir Balhar --- Lib/test/test_urlparse.py | 57 +++++++++++++++++++++++++++++++++++++++ Lib/urlparse.py | 10 +++++++ 2 files changed, 67 insertions(+) diff --git a/Lib/test/test_urlparse.py b/Lib/test/test_urlparse.py index 16eefed56f6..419e9c2bdcc 100644 --- a/Lib/test/test_urlparse.py +++ b/Lib/test/test_urlparse.py @@ -666,7 +666,64 @@ class UrlParseTestCase(unittest.TestCase): self.assertEqual(p.scheme, "https") self.assertEqual(p.geturl(), "https://www.python.org/javascript:alert('msg')/?query=something#fragment") + def test_urlsplit_strip_url(self): + noise = "".join([chr(i) for i in range(0, 0x20 + 1)]) + base_url = "http://User:Pass@www.python.org:080/doc/?query=yes#frag" + url = noise.decode("utf-8") + base_url + p = urlparse.urlsplit(url) + self.assertEqual(p.scheme, "http") + self.assertEqual(p.netloc, "User:Pass@www.python.org: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("utf-8") + p = urlparse.urlsplit(url) + self.assertEqual(p.scheme, b"http") + self.assertEqual(p.netloc, b"User:Pass@www.python.org: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("utf-8")) + + # Test that trailing space is preserved as some applications rely on + # this within query strings. + query_spaces_url = "https://www.python.org:88/doc/?query= " + p = urlparse.urlsplit(noise.decode("utf-8") + query_spaces_url) + self.assertEqual(p.scheme, "https") + self.assertEqual(p.netloc, "www.python.org:88") + self.assertEqual(p.path, "/doc/") + self.assertEqual(p.query, "query= ") + self.assertEqual(p.port, 88) + self.assertEqual(p.geturl(), query_spaces_url) + + p = urlparse.urlsplit("www.pypi.org ") + # That "hostname" gets considered a "path" due to the + # trailing space and our existing logic... YUCK... + # and re-assembles via geturl aka unurlsplit into the original. + # django.core.validators.URLValidator (at least through v3.2) relies on + # this, for better or worse, to catch it in a ValidationError via its + # regular expressions. + # Here we test the basic round trip concept of such a trailing space. + self.assertEqual(urlparse.urlunsplit(p), "www.pypi.org ") + + # with scheme as cache-key + url = "//www.python.org/" + scheme = noise.decode("utf-8") + "https" + noise.decode("utf-8") + for _ in range(2): + p = urlparse.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 non-integer ports.""" diff --git a/Lib/urlparse.py b/Lib/urlparse.py index 6cc40a8d2fb..0f03a7cc4a9 100644 --- a/Lib/urlparse.py +++ b/Lib/urlparse.py @@ -26,6 +26,10 @@ scenarios for parsing, and for backward compatibility purposes, some parsing quirks from older RFCs are retained. The testcases in test_urlparse.py provides a good indicator of parsing behavior. +The WHATWG URL Parser spec should also be considered. We are not compliant with +it either due to existing user code API behavior expectations (Hyrum's Law). +It serves as a useful guide when making changes. + """ import re @@ -63,6 +67,10 @@ scheme_chars = ('abcdefghijklmnopqrstuvwxyz' '0123456789' '+-.') +# Leading and trailing C0 control and space to be stripped per WHATWG spec. +# == "".join([chr(i) for i in range(0, 0x20 + 1)]) +_WHATWG_C0_CONTROL_OR_SPACE = '\x00\x01\x02\x03\x04\x05\x06\x07\x08\t\n\x0b\x0c\r\x0e\x0f\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f ' + # Unsafe bytes to be removed per WHATWG spec _UNSAFE_URL_BYTES_TO_REMOVE = ['\t', '\r', '\n'] @@ -201,6 +209,8 @@ def urlsplit(url, scheme='', allow_fragments=True): (e.g. netloc is a single string) and we don't expand % escapes.""" url = _remove_unsafe_bytes_from_url(url) scheme = _remove_unsafe_bytes_from_url(scheme) + url = url.lstrip(_WHATWG_C0_CONTROL_OR_SPACE) + scheme = scheme.strip(_WHATWG_C0_CONTROL_OR_SPACE) allow_fragments = bool(allow_fragments) key = url, scheme, allow_fragments, type(url), type(scheme) cached = _parse_cache.get(key, None)