# HG changeset patch # User Benjamin Peterson # Date 1417828515 18000 # Node ID d50096708b2d701937e78f525446d729fc28db88 # Parent 923aac88a3cc76a95d5a04d9d3ece245147a8064 add a default limit for the amount of data xmlrpclib.gzip_decode will return (closes #16043) diff --git a/Lib/test/test_xmlrpc.py b/Lib/test/test_xmlrpc.py --- a/Lib/test/test_xmlrpc.py +++ b/Lib/test/test_xmlrpc.py @@ -737,7 +737,7 @@ class GzipServerTestCase(BaseServerTestC with cm: p.pow(6, 8) - def test_gsip_response(self): + def test_gzip_response(self): t = self.Transport() p = xmlrpclib.ServerProxy(URL, transport=t) old = self.requestHandler.encode_threshold @@ -750,6 +750,23 @@ class GzipServerTestCase(BaseServerTestC self.requestHandler.encode_threshold = old self.assertTrue(a>b) + def test_gzip_decode_limit(self): + max_gzip_decode = 20 * 1024 * 1024 + data = '\0' * max_gzip_decode + encoded = xmlrpclib.gzip_encode(data) + decoded = xmlrpclib.gzip_decode(encoded) + self.assertEqual(len(decoded), max_gzip_decode) + + data = '\0' * (max_gzip_decode + 1) + encoded = xmlrpclib.gzip_encode(data) + + with self.assertRaisesRegexp(ValueError, + "max gzipped payload length exceeded"): + xmlrpclib.gzip_decode(encoded) + + xmlrpclib.gzip_decode(encoded, max_decode=-1) + + #Test special attributes of the ServerProxy object class ServerProxyTestCase(unittest.TestCase): def setUp(self): diff --git a/Lib/xmlrpclib.py b/Lib/xmlrpclib.py --- a/Lib/xmlrpclib.py +++ b/Lib/xmlrpclib.py @@ -49,6 +49,7 @@ # 2003-07-12 gp Correct marshalling of Faults # 2003-10-31 mvl Add multicall support # 2004-08-20 mvl Bump minimum supported Python version to 2.1 +# 2014-12-02 ch/doko Add workaround for gzip bomb vulnerability # # Copyright (c) 1999-2002 by Secret Labs AB. # Copyright (c) 1999-2002 by Fredrik Lundh. @@ -1165,10 +1166,13 @@ def gzip_encode(data): # in the HTTP header, as described in RFC 1952 # # @param data The encoded data +# @keyparam max_decode Maximum bytes to decode (20MB default), use negative +# values for unlimited decoding # @return the unencoded data # @raises ValueError if data is not correctly coded. +# @raises ValueError if max gzipped payload length exceeded -def gzip_decode(data): +def gzip_decode(data, max_decode=20971520): """gzip encoded data -> unencoded data Decode data using the gzip content encoding as described in RFC 1952 @@ -1178,11 +1182,16 @@ def gzip_decode(data): f = StringIO.StringIO(data) gzf = gzip.GzipFile(mode="rb", fileobj=f) try: - decoded = gzf.read() + if max_decode < 0: # no limit + decoded = gzf.read() + else: + decoded = gzf.read(max_decode + 1) except IOError: raise ValueError("invalid data") f.close() gzf.close() + if max_decode >= 0 and len(decoded) > max_decode: + raise ValueError("max gzipped payload length exceeded") return decoded ##