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- 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.
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