File CVE-2022-0391-urllib_parse-newline-parsing.patch of Package python-base
---
Doc/library/urlparse.rst | 14 ++
Doc/whatsnew/2.7.rst | 7 +
Lib/test/test_urlparse.py | 49 ++++++++++
Lib/urlparse.py | 12 ++
Misc/NEWS.d/next/Security/2021-04-25-07-46-37.bpo-43882.Jpwx85.rst | 6 +
5 files changed, 88 insertions(+)
--- a/Doc/library/urlparse.rst
+++ b/Doc/library/urlparse.rst
@@ -248,6 +248,10 @@ The :mod:`urlparse` module defines the f
decomposed before parsing, or is not a Unicode string, 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.
+
.. versionadded:: 2.2
.. versionchanged:: 2.5
@@ -257,6 +261,10 @@ The :mod:`urlparse` module defines the f
Characters that affect netloc parsing under NFKC normalization will
now raise :exc:`ValueError`.
+ .. versionchanged:: 3.6.14
+ ASCII newline and tab characters are stripped from the URL.
+
+.. _WHATWG spec: https://url.spec.whatwg.org/#concept-basic-url-parser
.. function:: urlunsplit(parts)
@@ -308,6 +316,11 @@ The :mod:`urlparse` module defines the f
.. 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 urlparse module
should conform to this. Certain deviations could be observed, which are
@@ -332,6 +345,7 @@ The :mod:`urlparse` module defines the f
:rfc:`1738` - Uniform Resource Locators (URL)
This specifies the formal syntax and semantics of absolute URLs.
+.. _WHATWG: https://url.spec.whatwg.org/
.. _urlparse-result-object:
--- a/Doc/whatsnew/2.7.rst
+++ b/Doc/whatsnew/2.7.rst
@@ -175,6 +175,13 @@ channel. We reuse the ftp server IP add
requiring the old behavior, set a ``trust_server_pasv_ipv4_address``
attribute on your FTP instance to ``True``. (See :issue:`43285`)
+The presence of newline or tab characters in parts of a URL allows for some
+forms of attacks. Following the WHATWG specification that updates RFC 3986,
+ASCII newline ``\n``, ``\r`` and tab ``\t`` characters are stripped from the
+URL by the parser :func:`urlparse` preventing such attacks. The removal
+characters are controlled by a new module level variable
+``urlparse._UNSAFE_URL_BYTES_TO_REMOVE``. (See :issue:`43882`)
+
Python 3.1 Features
=======================
--- a/Lib/test/test_urlparse.py
+++ b/Lib/test/test_urlparse.py
@@ -492,6 +492,55 @@ class UrlParseTestCase(unittest.TestCase
p = urlparse.urlsplit(url)
self.assertEqual(p.port, None)
+ def test_urlsplit_remove_unsafe_bytes(self):
+ # Remove ASCII tabs and newlines from input, for http common case scenario.
+ url = "h\nttp://www.python\n.org\t/java\nscript:\talert('msg\r\n')/?query\n=\tsomething#frag\nment"
+ p = urlparse.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, "query=something")
+ self.assertEqual(p.fragment, "fragment")
+ 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')/?query=something#fragment")
+
+ # Remove ASCII tabs and newlines from input as bytes, for http common case scenario.
+ url = b"h\nttp://www.python\n.org\t/java\nscript:\talert('msg\r\n')/?query\n=\tsomething#frag\nment"
+ p = urlparse.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"query=something")
+ self.assertEqual(p.fragment, b"fragment")
+ 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')/?query=something#fragment")
+
+ # any scheme
+ url = "x-new-scheme\t://www.python\n.org\t/java\nscript:\talert('msg\r\n')/?query\n=\tsomething#frag\nment"
+ p = urlparse.urlsplit(url)
+ self.assertEqual(p.geturl(), "x-new-scheme://www.python.org/javascript:alert('msg')/?query=something#fragment")
+
+ # Remove ASCII tabs and newlines from input as bytes, any scheme.
+ url = b"x-new-scheme\t://www.python\n.org\t/java\nscript:\talert('msg\r\n')/?query\n=\tsomething#frag\nment"
+ p = urlparse.urlsplit(url)
+ self.assertEqual(p.geturl(), b"x-new-scheme://www.python.org/javascript:alert('msg')/?query=something#fragment")
+
+ # Unsafe bytes is not returned from urlparse cache.
+ # scheme is stored after parsing, sending an scheme with unsafe bytes *will not* return an unsafe scheme
+ url = "https://www.python\n.org\t/java\nscript:\talert('msg\r\n')/?query\n=\tsomething#frag\nment"
+ scheme = "htt\nps"
+ for _ in range(2):
+ p = urlparse.urlsplit(url, scheme=scheme)
+ self.assertEqual(p.scheme, "https")
+ self.assertEqual(p.geturl(), "https://www.python.org/javascript:alert('msg')/?query=something#fragment")
+
+
def test_issue14072(self):
p1 = urlparse.urlsplit('tel:+31-641044153')
self.assertEqual(p1.scheme, 'tel')
--- a/Lib/urlparse.py
+++ b/Lib/urlparse.py
@@ -62,6 +62,9 @@ scheme_chars = ('abcdefghijklmnopqrstuvw
'0123456789'
'+-.')
+# Unsafe bytes to be removed per WHATWG spec
+_UNSAFE_URL_BYTES_TO_REMOVE = ['\t', '\r', '\n']
+
MAX_CACHE_SIZE = 20
_parse_cache = {}
@@ -184,12 +187,21 @@ def _checknetloc(netloc):
"under NFKC normalization"
% netloc)
+
+def _remove_unsafe_bytes_from_url(url):
+ for b in _UNSAFE_URL_BYTES_TO_REMOVE:
+ url = url.replace(b, "")
+ return url
+
+
def urlsplit(url, scheme='', allow_fragments=True):
"""Parse a URL into 5 components:
<scheme>://<netloc>/<path>?<query>#<fragment>
Return a 5-tuple: (scheme, netloc, path, query, fragment).
Note that we don't break the components up in smaller bits
(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)
allow_fragments = bool(allow_fragments)
key = url, scheme, allow_fragments, type(url), type(scheme)
cached = _parse_cache.get(key, None)
--- /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:`urlparse` now removes ASCII newlines and tabs from URLs,
+preventing such attacks.
