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python3-doc.18721
CVE-2021-23336-only-amp-as-query-sep.patch
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File CVE-2021-23336-only-amp-as-query-sep.patch of Package python3-doc.18721
From 5c17dfc5d70ce88be99bc5769b91ce79d7a90d61 Mon Sep 17 00:00:00 2001 From: Senthil Kumaran <senthil@uthcode.com> Date: Mon, 15 Feb 2021 11:16:43 -0800 Subject: [PATCH] [3.6] bpo-42967: only use '&' as a query string separator (GH-24297) (GH-24532) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit bpo-42967: [security] Address a web cache-poisoning issue reported in urllib.parse.parse_qsl(). urllib.parse will only us "&" as query string separator by default instead of both ";" and "&" as allowed in earlier versions. An optional argument seperator with default value "&" is added to specify the separator. Co-authored-by: Éric Araujo <merwok@netwok.org> Co-authored-by: Ken Jin <28750310+Fidget-Spinner@users.noreply.github.com> Co-authored-by: Adam Goldschmidt <adamgold7@gmail.com> --- Doc/library/cgi.rst | 8 +- Doc/library/urllib.parse.rst | 27 ++++++- Lib/cgi.py | 19 +++-- Lib/test/test_cgi.py | 29 ++++++- Lib/test/test_urlparse.py | 37 ++++++++++ Lib/urllib/parse.py | 17 +++- Misc/NEWS.d/next/Security/2021-02-14-15-59-16.bpo-42967.YApqDS.rst | 1 7 files changed, 117 insertions(+), 21 deletions(-) create mode 100644 Misc/NEWS.d/next/Security/2021-02-14-15-59-16.bpo-42967.YApqDS.rst --- a/Doc/library/cgi.rst +++ b/Doc/library/cgi.rst @@ -271,13 +271,12 @@ These are useful if you want more contro algorithms implemented in this module in other circumstances. -.. function:: parse(fp=None, environ=os.environ, keep_blank_values=False, strict_parsing=False) +.. function:: parse(fp=None, environ=os.environ, keep_blank_values=False, strict_parsing=False, separator="&") Parse a query in the environment or from a file (the file defaults to - ``sys.stdin``). The *keep_blank_values* and *strict_parsing* parameters are + ``sys.stdin``). The *keep_blank_values*, *strict_parsing* and *separator* parameters are passed to :func:`urllib.parse.parse_qs` unchanged. - .. function:: parse_qs(qs, keep_blank_values=False, strict_parsing=False) This function is deprecated in this module. Use :func:`urllib.parse.parse_qs` @@ -302,6 +301,9 @@ algorithms implemented in this module in Note that this does not parse nested multipart parts --- use :class:`FieldStorage` for that. + .. versionchanged:: 3.6.13 + Added the *separator* parameter. + .. function:: parse_header(string) --- a/Doc/library/urllib.parse.rst +++ b/Doc/library/urllib.parse.rst @@ -136,7 +136,9 @@ or on combining URL components into a UR now raise :exc:`ValueError`. -.. function:: parse_qs(qs, keep_blank_values=False, strict_parsing=False, encoding='utf-8', errors='replace') +.. function:: parse_qs(qs, keep_blank_values=False, + strict_parsing=False, encoding='utf-8', errors='replace', + max_num_fields=None, separator='&') Parse a query string given as a string argument (data of type :mimetype:`application/x-www-form-urlencoded`). Data are returned as a @@ -157,16 +159,26 @@ or on combining URL components into a UR percent-encoded sequences into Unicode characters, as accepted by the :meth:`bytes.decode` method. + The optional argument *separator* is the symbol to use for separating the + query arguments. It defaults to ``&``. + Use the :func:`urllib.parse.urlencode` function (with the ``doseq`` parameter set to ``True``) to convert such dictionaries into query strings. - .. versionchanged:: 3.2 Add *encoding* and *errors* parameters. + .. versionchanged:: 3.6.13 + Added *separator* parameter with the default value of ``&``. Python + versions earlier than Python 3.6.13 allowed using both ``;`` and ``&`` as + query parameter separator. This has been changed to allow only a single + separator key, with ``&`` as the default separator. + -.. function:: parse_qsl(qs, keep_blank_values=False, strict_parsing=False, encoding='utf-8', errors='replace') +.. function:: parse_qsl(qs, keep_blank_values=False, + strict_parsing=False, encoding='utf-8', errors='replace', + max_num_fields=None, separator='&') Parse a query string given as a string argument (data of type :mimetype:`application/x-www-form-urlencoded`). Data are returned as a list of @@ -186,12 +198,21 @@ or on combining URL components into a UR percent-encoded sequences into Unicode characters, as accepted by the :meth:`bytes.decode` method. + The optional argument *separator* is the symbol to use for separating the + query arguments. It defaults to ``&``. + Use the :func:`urllib.parse.urlencode` function to convert such lists of pairs into query strings. .. versionchanged:: 3.2 Add *encoding* and *errors* parameters. + .. versionchanged:: 3.6.13 + Added *separator* parameter with the default value of ``&``. Python + versions earlier than Python 3.6.13 allowed using both ``;`` and ``&`` as + query parameter separator. This has been changed to allow only a single + separator key, with ``&`` as the default separator. + .. function:: urlunparse(parts) --- a/Lib/cgi.py +++ b/Lib/cgi.py @@ -117,7 +117,8 @@ log = initlog # The current lo # 0 ==> unlimited input maxlen = 0 -def parse(fp=None, environ=os.environ, keep_blank_values=0, strict_parsing=0): +def parse(fp=None, environ=os.environ, keep_blank_values=0, + strict_parsing=0, separator='&'): """Parse a query in the environment or from a file (default stdin) Arguments, all optional: @@ -136,6 +137,9 @@ def parse(fp=None, environ=os.environ, k strict_parsing: flag indicating what to do with parsing errors. If false (the default), errors are silently ignored. If true, errors raise a ValueError exception. + + separator: str. The symbol to use for separating the query arguments. + Defaults to &. """ if fp is None: fp = sys.stdin @@ -180,7 +184,7 @@ def parse(fp=None, environ=os.environ, k qs = "" environ['QUERY_STRING'] = qs # XXX Shouldn't, really return urllib.parse.parse_qs(qs, keep_blank_values, strict_parsing, - encoding=encoding) + encoding=encoding, separator=separator) # parse query string function called from urlparse, @@ -404,7 +408,7 @@ class FieldStorage: """ def __init__(self, fp=None, headers=None, outerboundary=b'', environ=os.environ, keep_blank_values=0, strict_parsing=0, - limit=None, encoding='utf-8', errors='replace'): + limit=None, encoding='utf-8', errors='replace', separator='&'): """Constructor. Read multipart/* until last part. Arguments, all optional: @@ -448,6 +452,7 @@ class FieldStorage: method = 'GET' self.keep_blank_values = keep_blank_values self.strict_parsing = strict_parsing + self.separator = separator if 'REQUEST_METHOD' in environ: method = environ['REQUEST_METHOD'].upper() self.qs_on_post = None @@ -667,7 +672,8 @@ class FieldStorage: self.list = [] query = urllib.parse.parse_qsl( qs, self.keep_blank_values, self.strict_parsing, - encoding=self.encoding, errors=self.errors) + encoding=self.encoding, errors=self.errors, + separator=self.separator) for key, value in query: self.list.append(MiniFieldStorage(key, value)) self.skip_lines() @@ -683,7 +689,8 @@ class FieldStorage: if self.qs_on_post: query = urllib.parse.parse_qsl( self.qs_on_post, self.keep_blank_values, self.strict_parsing, - encoding=self.encoding, errors=self.errors) + encoding=self.encoding, errors=self.errors, + separator=self.separator) for key, value in query: self.list.append(MiniFieldStorage(key, value)) @@ -721,7 +728,7 @@ class FieldStorage: part = klass(self.fp, headers, ib, environ, keep_blank_values, strict_parsing,self.limit-self.bytes_read, - self.encoding, self.errors) + self.encoding, self.errors, self.separator) self.bytes_read += part.bytes_read self.list.append(part) if part.done or self.bytes_read >= self.length > 0: --- a/Lib/test/test_cgi.py +++ b/Lib/test/test_cgi.py @@ -54,12 +54,9 @@ parse_strict_test_cases = [ ("", ValueError("bad query field: ''")), ("&", ValueError("bad query field: ''")), ("&&", ValueError("bad query field: ''")), - (";", ValueError("bad query field: ''")), - (";&;", ValueError("bad query field: ''")), # Should the next few really be valid? ("=", {}), ("=&=", {}), - ("=;=", {}), # This rest seem to make sense ("=a", {'': ['a']}), ("&=a", ValueError("bad query field: ''")), @@ -74,8 +71,6 @@ parse_strict_test_cases = [ ("a=a+b&b=b+c", {'a': ['a b'], 'b': ['b c']}), ("a=a+b&a=b+a", {'a': ['a b', 'b a']}), ("x=1&y=2.0&z=2-3.%2b0", {'x': ['1'], 'y': ['2.0'], 'z': ['2-3.+0']}), - ("x=1;y=2.0&z=2-3.%2b0", {'x': ['1'], 'y': ['2.0'], 'z': ['2-3.+0']}), - ("x=1;y=2.0;z=2-3.%2b0", {'x': ['1'], 'y': ['2.0'], 'z': ['2-3.+0']}), ("Hbc5161168c542333633315dee1182227:key_store_seqid=400006&cuyer=r&view=bustomer&order_id=0bb2e248638833d48cb7fed300000f1b&expire=964546263&lobale=en-US&kid=130003.300038&ss=env", {'Hbc5161168c542333633315dee1182227:key_store_seqid': ['400006'], 'cuyer': ['r'], @@ -174,6 +169,30 @@ class CgiTests(unittest.TestCase): for key in expect.keys(): expect_val = expect[key] self.assertIn(key, fs) + if len(expect_val) > 1: + self.assertEqual(fs.getvalue(key), expect_val) + else: + self.assertEqual(fs.getvalue(key), expect_val[0]) + + def test_separator(self): + parse_semicolon = [ + ("x=1;y=2.0", {'x': ['1'], 'y': ['2.0']}), + ("x=1;y=2.0;z=2-3.%2b0", {'x': ['1'], 'y': ['2.0'], 'z': ['2-3.+0']}), + (";", ValueError("bad query field: ''")), + (";;", ValueError("bad query field: ''")), + ("=;a", ValueError("bad query field: 'a'")), + (";b=a", ValueError("bad query field: ''")), + ("b;=a", ValueError("bad query field: 'b'")), + ("a=a+b;b=b+c", {'a': ['a b'], 'b': ['b c']}), + ("a=a+b;a=b+a", {'a': ['a b', 'b a']}), + ] + for orig, expect in parse_semicolon: + env = {'QUERY_STRING': orig} + fs = cgi.FieldStorage(separator=';', environ=env) + if isinstance(expect, dict): + for key in expect.keys(): + expect_val = expect[key] + self.assertIn(key, fs) if len(expect_val) > 1: self.assertEqual(fs.getvalue(key), expect_val) else: --- a/Lib/test/test_urlparse.py +++ b/Lib/test/test_urlparse.py @@ -798,6 +798,43 @@ class UrlParseTestCase(unittest.TestCase errors="ignore") self.assertEqual(result, [('key', '\u0141-')]) + def test_parse_qs_separator(self): + parse_qs_semicolon_cases = [ + (";", {}), + (";;", {}), + (";a=b", {'a': ['b']}), + ("a=a+b;b=b+c", {'a': ['a b'], 'b': ['b c']}), + ("a=1;a=2", {'a': ['1', '2']}), + (b";", {}), + (b";;", {}), + (b";a=b", {b'a': [b'b']}), + (b"a=a+b;b=b+c", {b'a': [b'a b'], b'b': [b'b c']}), + (b"a=1;a=2", {b'a': [b'1', b'2']}), + ] + for orig, expect in parse_qs_semicolon_cases: + with self.subTest("Original: {!r}, Expected: {!r}".format(orig, expect)): + result = urllib.parse.parse_qs(orig, separator=';') + self.assertEqual(result, expect, "Error parsing %r" % orig) + + def test_parse_qsl_separator(self): + parse_qsl_semicolon_cases = [ + (";", []), + (";;", []), + (";a=b", [('a', 'b')]), + ("a=a+b;b=b+c", [('a', 'a b'), ('b', 'b c')]), + ("a=1;a=2", [('a', '1'), ('a', '2')]), + (b";", []), + (b";;", []), + (b";a=b", [(b'a', b'b')]), + (b"a=a+b;b=b+c", [(b'a', b'a b'), (b'b', b'b c')]), + (b"a=1;a=2", [(b'a', b'1'), (b'a', b'2')]), + ] + for orig, expect in parse_qsl_semicolon_cases: + with self.subTest("Original: {!r}, Expected: {!r}".format(orig, expect)): + result = urllib.parse.parse_qsl(orig, separator=';') + self.assertEqual(result, expect, "Error parsing %r" % orig) + + def test_urlencode_sequences(self): # Other tests incidentally urlencode things; test non-covered cases: # Sequence and object values. --- a/Lib/urllib/parse.py +++ b/Lib/urllib/parse.py @@ -553,7 +553,7 @@ def unquote(string, encoding='utf-8', er return ''.join(res) def parse_qs(qs, keep_blank_values=False, strict_parsing=False, - encoding='utf-8', errors='replace'): + encoding='utf-8', errors='replace', separator='&'): """Parse a query given as a string argument. Arguments: @@ -573,10 +573,13 @@ def parse_qs(qs, keep_blank_values=False encoding and errors: specify how to decode percent-encoded sequences into Unicode characters, as accepted by the bytes.decode() method. + + separator: str. The symbol to use for separating the query arguments. + Defaults to &. """ parsed_result = {} pairs = parse_qsl(qs, keep_blank_values, strict_parsing, - encoding=encoding, errors=errors) + encoding=encoding, errors=errors, separator=separator) for name, value in pairs: if name in parsed_result: parsed_result[name].append(value) @@ -585,7 +588,7 @@ def parse_qs(qs, keep_blank_values=False return parsed_result def parse_qsl(qs, keep_blank_values=False, strict_parsing=False, - encoding='utf-8', errors='replace'): + encoding='utf-8', errors='replace', separator='&'): """Parse a query given as a string argument. Arguments: @@ -605,10 +608,16 @@ def parse_qsl(qs, keep_blank_values=Fals encoding and errors: specify how to decode percent-encoded sequences into Unicode characters, as accepted by the bytes.decode() method. + separator: str. The symbol to use for separating the query arguments. + Defaults to &. + Returns a list, as G-d intended. """ qs, _coerce_result = _coerce_args(qs) - pairs = [s2 for s1 in qs.split('&') for s2 in s1.split(';')] + if not separator or (not isinstance(separator, (str, bytes))): + raise ValueError("Separator must be of type string or bytes.") + + pairs = [s1 for s1 in qs.split(separator)] r = [] for name_value in pairs: if not name_value and not strict_parsing: --- /dev/null +++ b/Misc/NEWS.d/next/Security/2021-02-14-15-59-16.bpo-42967.YApqDS.rst @@ -0,0 +1 @@ +Fix web cache poisoning vulnerability by defaulting the query args separator to ``&``, and allowing the user to choose a custom separator.
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