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From 3e3669c9c41a27e1466e2c28b3906e3dd0ce3e7e Mon Sep 17 00:00:00 2001
From: Steve Dower <steve.dower@python.org>
Date: Thu, 7 Mar 2019 08:25:22 -0800
Subject: [PATCH] bpo-36216: Add check for characters in netloc that normalize
to separators (GH-12201)
CVE: CVE-2019-9636
Upstream-Status: Backport https://github.com/python/cpython/pull/12216/commits/3e3669c9c41a27e1466e2c28b3906e3dd0ce3e7e
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>
---
Doc/library/urlparse.rst | 20 ++++++++++++++++
Lib/test/test_urlparse.py | 24 +++++++++++++++++++
Lib/urlparse.py | 17 +++++++++++++
.../2019-03-06-09-38-40.bpo-36216.6q1m4a.rst | 3 +++
4 files changed, 64 insertions(+)
create mode 100644 Misc/NEWS.d/next/Security/2019-03-06-09-38-40.bpo-36216.6q1m4a.rst
diff --git a/Lib/test/test_urlparse.py b/Lib/test/test_urlparse.py
index 4e1ded73c266..73b0228ea8e3 100644
--- a/Lib/test/test_urlparse.py
+++ b/Lib/test/test_urlparse.py
@@ -1,4 +1,6 @@
from test import test_support
+import sys
+import unicodedata
import unittest
import urlparse
@@ -624,6 +626,28 @@ def test_portseparator(self):
self.assertEqual(urlparse.urlparse("http://www.python.org:80"),
('http','www.python.org:80','','','',''))
+ def test_urlsplit_normalization(self):
+ # Certain characters should never occur in the netloc,
+ # including under normalization.
+ # Ensure that ALL of them are detected and cause an error
+ illegal_chars = u'/:#?@'
+ hex_chars = {'{:04X}'.format(ord(c)) for c in illegal_chars}
+ denorm_chars = [
+ c for c in map(unichr, range(128, sys.maxunicode))
+ if (hex_chars & set(unicodedata.decomposition(c).split()))
+ and c not in illegal_chars
+ ]
+ # Sanity check that we found at least one such character
+ self.assertIn(u'\u2100', denorm_chars)
+ self.assertIn(u'\uFF03', denorm_chars)
+
+ for scheme in [u"http", u"https", u"ftp"]:
+ for c in denorm_chars:
+ url = u"{}://netloc{}false.netloc/path".format(scheme, c)
+ print "Checking %r" % url
+ with self.assertRaises(ValueError):
+ urlparse.urlsplit(url)
+
def test_main():
test_support.run_unittest(UrlParseTestCase)
diff --git a/Lib/urlparse.py b/Lib/urlparse.py
index f7c2b032b097..54eda08651ab 100644
--- a/Lib/urlparse.py
+++ b/Lib/urlparse.py
@@ -165,6 +165,21 @@ def _splitnetloc(url, start=0):
delim = min(delim, wdelim) # use earliest delim position
return url[start:delim], url[delim:] # return (domain, rest)
+def _checknetloc(netloc):
+ if not netloc or not isinstance(netloc, unicode):
+ return
+ # looking for characters like \u2100 that expand to 'a/c'
+ # IDNA uses NFKC equivalence, so normalize for this check
+ import unicodedata
+ netloc2 = unicodedata.normalize('NFKC', netloc)
+ if netloc == netloc2:
+ return
+ _, _, netloc = netloc.rpartition('@') # anything to the left of '@' is okay
+ for c in '/?#@:':
+ if c in netloc2:
+ raise ValueError("netloc '" + netloc2 + "' contains invalid " +
+ "characters under NFKC normalization")
+
def urlsplit(url, scheme='', allow_fragments=True):
"""Parse a URL into 5 components:
<scheme>://<netloc>/<path>?<query>#<fragment>
@@ -193,6 +208,7 @@ def urlsplit(url, scheme='', allow_fragments=True):
url, fragment = url.split('#', 1)
if '?' in url:
url, query = url.split('?', 1)
+ _checknetloc(netloc)
v = SplitResult(scheme, netloc, url, query, fragment)
_parse_cache[key] = v
return v
@@ -216,6 +232,7 @@ def urlsplit(url, scheme='', allow_fragments=True):
url, fragment = url.split('#', 1)
if '?' in url:
url, query = url.split('?', 1)
+ _checknetloc(netloc)
v = SplitResult(scheme, netloc, url, query, fragment)
_parse_cache[key] = v
return v
diff --git a/Misc/NEWS.d/next/Security/2019-03-06-09-38-40.bpo-36216.6q1m4a.rst b/Misc/NEWS.d/next/Security/2019-03-06-09-38-40.bpo-36216.6q1m4a.rst
new file mode 100644
index 000000000000..1e1ad92c6feb
--- /dev/null
+++ b/Misc/NEWS.d/next/Security/2019-03-06-09-38-40.bpo-36216.6q1m4a.rst
@@ -0,0 +1,3 @@
+Changes urlsplit() to raise ValueError when the URL contains characters that
+decompose under IDNA encoding (NFKC-normalization) into characters that
+affect how the URL is parsed.
\ No newline at end of file
|
