58d0bc2f29
Fixes CVE-2019-9636: urlsplit does not handle NFKC normalization https://bugs.python.org/issue36216 The fix unfortunately introduced regressions, so also apply the followup fixes. https://bugs.python.org/issue36742 Signed-off-by: Peter Korsgaard <peter@korsgaard.com> Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
160 lines
6.2 KiB
Diff
160 lines
6.2 KiB
Diff
From e37ef41289b77e0f0bb9a6aedb0360664c55bdd5 Mon Sep 17 00:00:00 2001
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From: Steve Dower <steve.dower@microsoft.com>
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Date: Thu, 7 Mar 2019 09:08:45 -0800
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Subject: [PATCH] bpo-36216: Add check for characters in netloc that normalize
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to separators (GH-12201)
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Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
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---
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Doc/library/urlparse.rst | 20 ++++++++++++++++++
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Lib/test/test_urlparse.py | 24 ++++++++++++++++++++++
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Lib/urlparse.py | 17 +++++++++++++++
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.../2019-03-06-09-38-40.bpo-36216.6q1m4a.rst | 3 +++
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4 files changed, 64 insertions(+)
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create mode 100644 Misc/NEWS.d/next/Security/2019-03-06-09-38-40.bpo-36216.6q1m4a.rst
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diff --git a/Doc/library/urlparse.rst b/Doc/library/urlparse.rst
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index 22249da54f..0989c88c30 100644
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--- a/Doc/library/urlparse.rst
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+++ b/Doc/library/urlparse.rst
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@@ -119,12 +119,22 @@ The :mod:`urlparse` module defines the following functions:
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See section :ref:`urlparse-result-object` for more information on the result
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object.
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+ Characters in the :attr:`netloc` attribute that decompose under NFKC
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+ normalization (as used by the IDNA encoding) into any of ``/``, ``?``,
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+ ``#``, ``@``, or ``:`` will raise a :exc:`ValueError`. If the URL is
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+ decomposed before parsing, or is not a Unicode string, no error will be
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+ raised.
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+
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.. versionchanged:: 2.5
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Added attributes to return value.
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.. versionchanged:: 2.7
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Added IPv6 URL parsing capabilities.
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+ .. versionchanged:: 2.7.17
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+ Characters that affect netloc parsing under NFKC normalization will
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+ now raise :exc:`ValueError`.
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+
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.. function:: parse_qs(qs[, keep_blank_values[, strict_parsing[, max_num_fields]]])
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@@ -232,11 +242,21 @@ The :mod:`urlparse` module defines the following functions:
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See section :ref:`urlparse-result-object` for more information on the result
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object.
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+ Characters in the :attr:`netloc` attribute that decompose under NFKC
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+ normalization (as used by the IDNA encoding) into any of ``/``, ``?``,
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+ ``#``, ``@``, or ``:`` will raise a :exc:`ValueError`. If the URL is
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+ decomposed before parsing, or is not a Unicode string, no error will be
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+ raised.
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+
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.. versionadded:: 2.2
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.. versionchanged:: 2.5
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Added attributes to return value.
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+ .. versionchanged:: 2.7.17
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+ Characters that affect netloc parsing under NFKC normalization will
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+ now raise :exc:`ValueError`.
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+
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.. function:: urlunsplit(parts)
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diff --git a/Lib/test/test_urlparse.py b/Lib/test/test_urlparse.py
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index 4e1ded73c2..73b0228ea8 100644
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--- a/Lib/test/test_urlparse.py
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+++ b/Lib/test/test_urlparse.py
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@@ -1,4 +1,6 @@
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from test import test_support
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+import sys
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+import unicodedata
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import unittest
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import urlparse
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@@ -624,6 +626,28 @@ class UrlParseTestCase(unittest.TestCase):
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self.assertEqual(urlparse.urlparse("http://www.python.org:80"),
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('http','www.python.org:80','','','',''))
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+ def test_urlsplit_normalization(self):
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+ # Certain characters should never occur in the netloc,
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+ # including under normalization.
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+ # Ensure that ALL of them are detected and cause an error
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+ illegal_chars = u'/:#?@'
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+ hex_chars = {'{:04X}'.format(ord(c)) for c in illegal_chars}
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+ denorm_chars = [
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+ c for c in map(unichr, range(128, sys.maxunicode))
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+ if (hex_chars & set(unicodedata.decomposition(c).split()))
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+ and c not in illegal_chars
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+ ]
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+ # Sanity check that we found at least one such character
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+ self.assertIn(u'\u2100', denorm_chars)
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+ self.assertIn(u'\uFF03', denorm_chars)
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+
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+ for scheme in [u"http", u"https", u"ftp"]:
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+ for c in denorm_chars:
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+ url = u"{}://netloc{}false.netloc/path".format(scheme, c)
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+ print "Checking %r" % url
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+ with self.assertRaises(ValueError):
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+ urlparse.urlsplit(url)
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+
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def test_main():
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test_support.run_unittest(UrlParseTestCase)
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diff --git a/Lib/urlparse.py b/Lib/urlparse.py
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index f7c2b032b0..54eda08651 100644
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--- a/Lib/urlparse.py
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+++ b/Lib/urlparse.py
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@@ -165,6 +165,21 @@ def _splitnetloc(url, start=0):
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delim = min(delim, wdelim) # use earliest delim position
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return url[start:delim], url[delim:] # return (domain, rest)
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+def _checknetloc(netloc):
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+ if not netloc or not isinstance(netloc, unicode):
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+ return
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+ # looking for characters like \u2100 that expand to 'a/c'
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+ # IDNA uses NFKC equivalence, so normalize for this check
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+ import unicodedata
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+ netloc2 = unicodedata.normalize('NFKC', netloc)
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+ if netloc == netloc2:
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+ return
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+ _, _, netloc = netloc.rpartition('@') # anything to the left of '@' is okay
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+ for c in '/?#@:':
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+ if c in netloc2:
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+ raise ValueError("netloc '" + netloc2 + "' contains invalid " +
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+ "characters under NFKC normalization")
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+
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def urlsplit(url, scheme='', allow_fragments=True):
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"""Parse a URL into 5 components:
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<scheme>://<netloc>/<path>?<query>#<fragment>
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@@ -193,6 +208,7 @@ def urlsplit(url, scheme='', allow_fragments=True):
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url, fragment = url.split('#', 1)
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if '?' in url:
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url, query = url.split('?', 1)
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+ _checknetloc(netloc)
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v = SplitResult(scheme, netloc, url, query, fragment)
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_parse_cache[key] = v
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return v
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@@ -216,6 +232,7 @@ def urlsplit(url, scheme='', allow_fragments=True):
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url, fragment = url.split('#', 1)
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if '?' in url:
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url, query = url.split('?', 1)
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+ _checknetloc(netloc)
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v = SplitResult(scheme, netloc, url, query, fragment)
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_parse_cache[key] = v
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return v
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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
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new file mode 100644
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index 0000000000..1e1ad92c6f
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--- /dev/null
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+++ b/Misc/NEWS.d/next/Security/2019-03-06-09-38-40.bpo-36216.6q1m4a.rst
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@@ -0,0 +1,3 @@
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+Changes urlsplit() to raise ValueError when the URL contains characters that
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+decompose under IDNA encoding (NFKC-normalization) into characters that
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+affect how the URL is parsed.
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\ No newline at end of file
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--
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2.11.0
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