From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001

From: Charalampos Stratakis <cstratak@redhat.com>

Date: Tue, 8 Feb 2022 01:51:44 +0100

Subject: [PATCH] 00377-CVE-2022-0391.patch

00377 #

CVE-2022-0391: urlparse does not sanitize URLs containing ASCII newline and tabs

ASCII newline and tab characters are stripped from the URL.

Upstream: https://bugs.python.org/issue43882

Backported from Python 3.

Co-authored-by: Gregory P. Smith <greg@krypto.org>

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

Co-authored-by: Senthil Kumaran <senthil@uthcode.com>

---

 Doc/library/urlparse.rst  |  8 +++++++

 Lib/test/test_urlparse.py | 49 +++++++++++++++++++++++++++++++++++++++

 Lib/urlparse.py           | 10 ++++++++

 3 files changed, 67 insertions(+)

diff --git a/Doc/library/urlparse.rst b/Doc/library/urlparse.rst

index 97d1119257c..c08c3dc8e8f 100644

--- a/Doc/library/urlparse.rst

+++ b/Doc/library/urlparse.rst

@@ -125,6 +125,9 @@ The :mod:`urlparse` module defines the following functions:

    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.

+

    .. versionchanged:: 2.5

       Added attributes to return value.

@@ -321,6 +324,10 @@ The :mod:`urlparse` module defines the following functions:

 .. 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

@@ -345,6 +352,7 @@ The :mod:`urlparse` module defines the following functions:

    :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:

diff --git a/Lib/test/test_urlparse.py b/Lib/test/test_urlparse.py

index 21875bb2991..16eefed56f6 100644

--- a/Lib/test/test_urlparse.py

+++ b/Lib/test/test_urlparse.py

@@ -618,6 +618,55 @@ class UrlParseTestCase(unittest.TestCase):

         self.assertEqual(p1.path, '863-1234')

         self.assertEqual(p1.params, 'phone-context=+1-914-555')

+    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_attributes_bad_port(self):

         """Check handling of non-integer ports."""

diff --git a/Lib/urlparse.py b/Lib/urlparse.py

index 69504d8fd93..6cc40a8d2fb 100644

--- a/Lib/urlparse.py

+++ b/Lib/urlparse.py

@@ -63,6 +63,9 @@ scheme_chars = ('abcdefghijklmnopqrstuvwxyz'

                 '0123456789'

                 '+-.')

+# Unsafe bytes to be removed per WHATWG spec

+_UNSAFE_URL_BYTES_TO_REMOVE = ['\t', '\r', '\n']

+

 MAX_CACHE_SIZE = 20

 _parse_cache = {}

@@ -185,12 +188,19 @@ 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)