Merge pull request #8546 from jefferyto/python-bpo-36216

python,python3: Fix CVE-2019-9636 - urlsplit missing NFKC normalization
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Hannu Nyman 2019-03-31 13:19:43 +03:00 committed by GitHub
commit abfd6d81ed
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5 changed files with 330 additions and 2 deletions

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@ -12,7 +12,7 @@ include ../python-version.mk
PKG_NAME:=python
PKG_VERSION:=$(PYTHON_VERSION).$(PYTHON_VERSION_MICRO)
PKG_RELEASE:=2
PKG_RELEASE:=3
PKG_SOURCE:=Python-$(PKG_VERSION).tar.xz
PKG_SOURCE_URL:=https://www.python.org/ftp/python/$(PKG_VERSION)

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@ -0,0 +1,155 @@
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)
---
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/Doc/library/urlparse.rst b/Doc/library/urlparse.rst
index 22249da54fbb..0989c88c3022 100644
--- a/Doc/library/urlparse.rst
+++ b/Doc/library/urlparse.rst
@@ -119,12 +119,22 @@ The :mod:`urlparse` module defines the following functions:
See section :ref:`urlparse-result-object` for more information on the result
object.
+ Characters in the :attr:`netloc` attribute that decompose under NFKC
+ normalization (as used by the IDNA encoding) into any of ``/``, ``?``,
+ ``#``, ``@``, or ``:`` will raise a :exc:`ValueError`. If the URL is
+ decomposed before parsing, or is not a Unicode string, no error will be
+ raised.
+
.. versionchanged:: 2.5
Added attributes to return value.
.. versionchanged:: 2.7
Added IPv6 URL parsing capabilities.
+ .. versionchanged:: 2.7.17
+ Characters that affect netloc parsing under NFKC normalization will
+ now raise :exc:`ValueError`.
+
.. function:: parse_qs(qs[, keep_blank_values[, strict_parsing[, max_num_fields]]])
@@ -232,11 +242,21 @@ The :mod:`urlparse` module defines the following functions:
See section :ref:`urlparse-result-object` for more information on the result
object.
+ Characters in the :attr:`netloc` attribute that decompose under NFKC
+ normalization (as used by the IDNA encoding) into any of ``/``, ``?``,
+ ``#``, ``@``, or ``:`` will raise a :exc:`ValueError`. If the URL is
+ decomposed before parsing, or is not a Unicode string, no error will be
+ raised.
+
.. versionadded:: 2.2
.. versionchanged:: 2.5
Added attributes to return value.
+ .. versionchanged:: 2.7.17
+ Characters that affect netloc parsing under NFKC normalization will
+ now raise :exc:`ValueError`.
+
.. function:: urlunsplit(parts)
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

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@ -0,0 +1,23 @@
From 06b5ee585d6e76bdbb4002f642d864d860cbbd2b Mon Sep 17 00:00:00 2001
From: Steve Dower <steve.dower@python.org>
Date: Tue, 12 Mar 2019 08:23:33 -0700
Subject: [PATCH] bpo-36216: Only print test messages when verbose
---
Lib/test/test_urlparse.py | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/Lib/test/test_urlparse.py b/Lib/test/test_urlparse.py
index 73b0228ea8e3..1830d0b28688 100644
--- a/Lib/test/test_urlparse.py
+++ b/Lib/test/test_urlparse.py
@@ -644,7 +644,8 @@ def test_urlsplit_normalization(self):
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
+ if test_support.verbose:
+ print "Checking %r" % url
with self.assertRaises(ValueError):
urlparse.urlsplit(url)

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@ -14,7 +14,7 @@ PYTHON_VERSION:=$(PYTHON3_VERSION)
PYTHON_VERSION_MICRO:=$(PYTHON3_VERSION_MICRO)
PKG_NAME:=python3
PKG_RELEASE:=8
PKG_RELEASE:=9
PKG_VERSION:=$(PYTHON_VERSION).$(PYTHON_VERSION_MICRO)
PKG_SOURCE:=Python-$(PKG_VERSION).tar.xz

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@ -0,0 +1,150 @@
From 30a779770fe690584456970b602ea16ec3f74ce7 Mon Sep 17 00:00:00 2001
From: Steve Dower <steve.dower@python.org>
Date: Thu, 7 Mar 2019 08:05:31 -0800
Subject: [PATCH] bpo-36216: Add check for characters in netloc that normalize
to separators (GH-12201)
---
Doc/library/urllib.parse.rst | 18 +++++++++++++++
Lib/test/test_urlparse.py | 23 +++++++++++++++++++
Lib/urllib/parse.py | 17 ++++++++++++++
.../2019-03-06-09-38-40.bpo-36216.6q1m4a.rst | 3 +++
4 files changed, 61 insertions(+)
create mode 100644 Misc/NEWS.d/next/Security/2019-03-06-09-38-40.bpo-36216.6q1m4a.rst
diff --git a/Doc/library/urllib.parse.rst b/Doc/library/urllib.parse.rst
index 0c8f0f607314..b565e1edd321 100644
--- a/Doc/library/urllib.parse.rst
+++ b/Doc/library/urllib.parse.rst
@@ -124,6 +124,11 @@ or on combining URL components into a URL string.
Unmatched square brackets in the :attr:`netloc` attribute will raise a
:exc:`ValueError`.
+ Characters in the :attr:`netloc` attribute that decompose under NFKC
+ normalization (as used by the IDNA encoding) into any of ``/``, ``?``,
+ ``#``, ``@``, or ``:`` will raise a :exc:`ValueError`. If the URL is
+ decomposed before parsing, no error will be raised.
+
.. versionchanged:: 3.2
Added IPv6 URL parsing capabilities.
@@ -136,6 +141,10 @@ or on combining URL components into a URL string.
Out-of-range port numbers now raise :exc:`ValueError`, instead of
returning :const:`None`.
+ .. versionchanged:: 3.7.3
+ Characters that affect netloc parsing under NFKC normalization will
+ now raise :exc:`ValueError`.
+
.. function:: parse_qs(qs, keep_blank_values=False, strict_parsing=False, encoding='utf-8', errors='replace', max_num_fields=None)
@@ -257,10 +266,19 @@ or on combining URL components into a URL string.
Unmatched square brackets in the :attr:`netloc` attribute will raise a
:exc:`ValueError`.
+ Characters in the :attr:`netloc` attribute that decompose under NFKC
+ normalization (as used by the IDNA encoding) into any of ``/``, ``?``,
+ ``#``, ``@``, or ``:`` will raise a :exc:`ValueError`. If the URL is
+ decomposed before parsing, no error will be raised.
+
.. versionchanged:: 3.6
Out-of-range port numbers now raise :exc:`ValueError`, instead of
returning :const:`None`.
+ .. versionchanged:: 3.7.3
+ Characters that affect netloc parsing under NFKC normalization will
+ now raise :exc:`ValueError`.
+
.. function:: urlunsplit(parts)
diff --git a/Lib/test/test_urlparse.py b/Lib/test/test_urlparse.py
index be50b47603aa..e6638aee2244 100644
--- a/Lib/test/test_urlparse.py
+++ b/Lib/test/test_urlparse.py
@@ -1,3 +1,5 @@
+import sys
+import unicodedata
import unittest
import urllib.parse
@@ -984,6 +986,27 @@ def test_all(self):
expected.append(name)
self.assertCountEqual(urllib.parse.__all__, expected)
+ 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 = '/:#?@'
+ hex_chars = {'{:04X}'.format(ord(c)) for c in illegal_chars}
+ denorm_chars = [
+ c for c in map(chr, 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('\u2100', denorm_chars)
+ self.assertIn('\uFF03', denorm_chars)
+
+ for scheme in ["http", "https", "ftp"]:
+ for c in denorm_chars:
+ url = "{}://netloc{}false.netloc/path".format(scheme, c)
+ with self.subTest(url=url, char='{:04X}'.format(ord(c))):
+ with self.assertRaises(ValueError):
+ urllib.parse.urlsplit(url)
class Utility_Tests(unittest.TestCase):
"""Testcase to test the various utility functions in the urllib."""
diff --git a/Lib/urllib/parse.py b/Lib/urllib/parse.py
index f691ab74f87f..39c5d6a80824 100644
--- a/Lib/urllib/parse.py
+++ b/Lib/urllib/parse.py
@@ -391,6 +391,21 @@ 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 netloc.isascii():
+ 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>
@@ -419,6 +434,7 @@ def urlsplit(url, scheme='', allow_fragments=True):
url, fragment = url.split('#', 1)
if '?' in url:
url, query = url.split('?', 1)
+ _checknetloc(netloc)
v = SplitResult('http', netloc, url, query, fragment)
_parse_cache[key] = v
return _coerce_result(v)
@@ -442,6 +458,7 @@ 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 _coerce_result(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..5546394157f9
--- /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.