diff options
author | V3n3RiX <venerix@redcorelinux.org> | 2020-02-29 18:01:47 +0000 |
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committer | V3n3RiX <venerix@redcorelinux.org> | 2020-02-29 18:01:47 +0000 |
commit | ceeeb463cc1eef97fd62eaee8bf2196ba04bc384 (patch) | |
tree | 9f47ee47c31a0f13f9496879cd88a1042550aa81 /dev-python/pysaml2/files | |
parent | 53cba99042fa967e2a93da9f8db806fe2d035543 (diff) |
gentoo (leap year) resync : 29.02.2020
Diffstat (limited to 'dev-python/pysaml2/files')
-rw-r--r-- | dev-python/pysaml2/files/cve-2020-5390.patch | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/dev-python/pysaml2/files/cve-2020-5390.patch b/dev-python/pysaml2/files/cve-2020-5390.patch new file mode 100644 index 000000000000..bef46808d920 --- /dev/null +++ b/dev-python/pysaml2/files/cve-2020-5390.patch @@ -0,0 +1,189 @@ +From 5e9d5acbcd8ae45c4e736ac521fd2df5b1c62e25 Mon Sep 17 00:00:00 2001 +From: Ivan Kanakarakis <ivan.kanak@gmail.com> +Date: Sat, 4 Jan 2020 00:39:47 +0200 +Subject: [PATCH] Fix XML Signature Wrapping (XSW) vulnerabilities + +PySAML2 did not check that the signature in a SAML document is enveloped and thus +XML signature wrapping (XSW) was effective. + +The signature information and the node/object that is signed can be in different places +and thus the signature verification will succeed, but the wrong data will be used. This +specifically affects the verification of assertions that have been signed. + +This was assigned CVE-2020-5390 + +Thanks to Alexey Sintsov and Yuri Goltsev from HERE Technologies to report this. + ++ + + + + + + + + +In more detail: + +libxml2 follows the xmldsig-core specification. The xmldsig specification is way too +general. saml-core reuses the xmldsig specification, but constrains it to use of +specific facilities. The implementation of the SAML specification is responsible to +enforce those constraints. libxml2/xmlsec1 are not aware of those constraints and thus +process the document based on the full/general xmldsig rules. + +What is happening is the following: + +- xmldsig-core allows the signature-information and the data that was signed to be in + different places. This works by setting the URI attribute of the Reference element. + The URI attribute contains an optional identifier of the object being signed. (see + "4.4.3 The Reference Element" -- https://www.w3.org/TR/xmldsig-core1/#sec-Reference) + This identifier is actually a pointer that can be defined in many different ways; from + XPath expressions that need to be executed(!), to a full URL that should be fetched(!) + in order to recalculate the signature. + +- saml-core section "5.4 XML Signature Profile" defines constrains on the xmldsig-core + facilities. It explicitly dictates that enveloped signatures are the only signatures + allowed. This mean that: + * Assertion/RequestType/ResponseType elements must have an ID attribute + * signatures must have a single Reference element + * the Reference element must have a URI attribute + * the URI attribute contains an anchor + * the anchor points to the enclosing element's ID attribute + +xmlsec1 does the right thing - it follows the reference URI pointer and validates the +assertion. But, the pointer points to an assertion in another part of the document; not +the assertion in which the signature is embedded/enveloped. SAML processing thinks that +the signature is fine (that's what xmlsec1 said), and gets the assertion data from the +assertion that contains the signature - but that assertion was never validated. The +issue is that pysaml2 does not enforce the constrains on the signature validation +facilities of xmldsig-core, that the saml-core spec defines. + +The solution is simple; all we need is to make sure that assertions with signatures (1) +contain one reference element that (2) has a URI attribute (3) that is an anchor that +(4) points to the assertion in which the signature is embedded. If those conditions are +met then we're good, otherwise we should fail the verification. + +Signed-off-by: Ivan Kanakarakis <ivan.kanak@gmail.com> +--- + src/saml2/sigver.py | 49 ++++++++++++++++++++++++++++++++++++ + tests/saml2_response_xsw.xml | 6 +++++ + tests/test_xsw.py | 44 ++++++++++++++++++++++++++++++++ + 3 files changed, 99 insertions(+) + create mode 100644 tests/saml2_response_xsw.xml + create mode 100644 tests/test_xsw.py + +diff --git a/src/saml2/sigver.py b/src/saml2/sigver.py +index cbeca41f..c3d298a9 100644 +--- a/src/saml2/sigver.py ++++ b/src/saml2/sigver.py +@@ -1476,6 +1476,55 @@ def _check_signature(self, decoded_xml, item, node_name=NODE_NAME, origdoc=None, + if not certs: + raise MissingKey(_issuer) + ++ # saml-core section "5.4 XML Signature Profile" defines constrains on the ++ # xmldsig-core facilities. It explicitly dictates that enveloped signatures ++ # are the only signatures allowed. This mean that: ++ # * Assertion/RequestType/ResponseType elements must have an ID attribute ++ # * signatures must have a single Reference element ++ # * the Reference element must have a URI attribute ++ # * the URI attribute contains an anchor ++ # * the anchor points to the enclosing element's ID attribute ++ references = item.signature.signed_info.reference ++ signatures_must_have_a_single_reference_element = len(references) == 1 ++ the_Reference_element_must_have_a_URI_attribute = ( ++ signatures_must_have_a_single_reference_element ++ and hasattr(references[0], "uri") ++ ) ++ the_URI_attribute_contains_an_anchor = ( ++ the_Reference_element_must_have_a_URI_attribute ++ and references[0].uri.startswith("#") ++ and len(references[0].uri) > 1 ++ ) ++ the_anchor_points_to_the_enclosing_element_ID_attribute = ( ++ the_URI_attribute_contains_an_anchor ++ and references[0].uri == "#{id}".format(id=item.id) ++ ) ++ validators = { ++ "signatures must have a single reference element": ( ++ signatures_must_have_a_single_reference_element ++ ), ++ "the Reference element must have a URI attribute": ( ++ the_Reference_element_must_have_a_URI_attribute ++ ), ++ "the URI attribute contains an anchor": ( ++ the_URI_attribute_contains_an_anchor ++ ), ++ "the anchor points to the enclosing element ID attribute": ( ++ the_anchor_points_to_the_enclosing_element_ID_attribute ++ ), ++ } ++ if not all(validators.values()): ++ error_context = { ++ "message": "Signature failed to meet constraints on xmldsig", ++ "validators": validators, ++ "item ID": item.id, ++ "reference URI": item.signature.signed_info.reference[0].uri, ++ "issuer": _issuer, ++ "node name": node_name, ++ "xml document": decoded_xml, ++ } ++ raise SignatureError(error_context) ++ + verified = False + last_pem_file = None + +diff --git a/tests/saml2_response_xsw.xml b/tests/saml2_response_xsw.xml +new file mode 100644 +index 00000000..3671eb48 +--- /dev/null ++++ b/tests/saml2_response_xsw.xml +@@ -0,0 +1,6 @@ ++<?xml version="1.0" encoding="UTF-8"?> ++<ns0:Response xmlns:ns0="urn:oasis:names:tc:SAML:2.0:protocol" xmlns:ns1="urn:oasis:names:tc:SAML:2.0:assertion" xmlns:ns2="http://www.w3.org/2000/09/xmldsig#" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" Destination="http://lingon.catalogix.se:8087/" ID="id-vqOQ72JCppXaBWnBE" InResponseTo="id12" IssueInstant="2019-12-20T12:15:16Z" Version="2.0"><ns1:Issuer Format="urn:oasis:names:tc:SAML:2.0:nameid-format:entity">urn:mace:example.com:saml:roland:idp</ns1:Issuer><ns0:Status><ns0:StatusCode Value="urn:oasis:names:tc:SAML:2.0:status:Success"/></ns0:Status><ns1:Assertion ID="id-SPOOFED_ASSERTION" IssueInstant="2019-12-20T12:15:16Z" Version="2.0"><ns1:Issuer Format="urn:oasis:names:tc:SAML:2.0:nameid-format:entity">urn:mace:example.com:saml:roland:idp</ns1:Issuer><ns2:Signature Id="Signature2"><ns2:SignedInfo><ns2:CanonicalizationMethod Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/><ns2:SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1"/><ns2:Reference URI="#id-Aa9IWfDxJVIX6GQye"><ns2:Transforms><ns2:Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature"/><ns2:Transform Algorithm="http://www.w3.org/2001/10/xml-exc-c14n#"/></ns2:Transforms><ns2:DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1"/><ns2:DigestValue>EWBvQUlrwQbtrAjuUXkSBAVsZ50=</ns2:DigestValue></ns2:Reference></ns2:SignedInfo><ns2:SignatureValue>m4zRgTWleMcx1dFboeiYlbiDigHWAVhHVa+GLN++ELNMFDutuzBxc3tu6okyaNQGW3leu32wzbfdpb5+3RlpGoKj2wPX570/EMJj4uw91XfXsZfpNP+5GlgNT8w/elDmBXhG/KwmSO477Imk0szKovTBMVHmo3QOd+ba//dVsJE=</ns2:SignatureValue><ns2:KeyInfo><ns2:X509Data><ns2:X509Certificate>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</ns2:X509Certificate></ns2:X509Data></ns2:KeyInfo></ns2:Signature><ns1:Subject><ns1:NameID Format="urn:oasis:names:tc:SAML:2.0:nameid-format:transient" NameQualifier="" SPNameQualifier="id12">ANOTHER_ID</ns1:NameID><ns1:SubjectConfirmation Method="urn:oasis:names:tc:SAML:2.0:cm:bearer"><ns1:SubjectConfirmationData InResponseTo="id12" NotOnOrAfter="2019-12-20T12:20:16Z" Recipient="http://lingon.catalogix.se:8087/"/></ns1:SubjectConfirmation></ns1:Subject><ns1:Conditions NotBefore="2019-12-20T12:15:16Z" NotOnOrAfter="2019-12-20T12:20:16Z"><ns1:AudienceRestriction><ns1:Audience>urn:mace:example.com:saml:roland:sp</ns1:Audience></ns1:AudienceRestriction></ns1:Conditions><ns1:AuthnStatement AuthnInstant="2019-12-20T12:15:16Z" SessionIndex="id-eEhNCc5BSiesVOl8B"><ns1:AuthnContext><ns1:AuthnContextClassRef>urn:oasis:names:tc:SAML:2.0:ac:classes:InternetProtocolPassword</ns1:AuthnContextClassRef><ns1:AuthenticatingAuthority>http://www.example.com/login</ns1:AuthenticatingAuthority></ns1:AuthnContext></ns1:AuthnStatement><ns1:AttributeStatement><ns1:Attribute FriendlyName="eduPersonAffiliation" Name="urn:oid:1.3.6.1.4.1.5923.1.1.1.1" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri"><ns1:AttributeValue xmlns:xs="http://www.w3.org/2001/XMLSchema" xsi:type="xs:string">staff</ns1:AttributeValue><ns1:AttributeValue xmlns:xs="http://www.w3.org/2001/XMLSchema" xsi:type="xs:string">ADMIN</ns1:AttributeValue></ns1:Attribute><ns1:Attribute FriendlyName="mail" Name="urn:oid:0.9.2342.19200300.100.1.3" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri"><ns1:AttributeValue xmlns:xs="http://www.w3.org/2001/XMLSchema" xsi:type="xs:string">HACKER@gmail.com</ns1:AttributeValue></ns1:Attribute><ns1:Attribute FriendlyName="givenName" Name="urn:oid:2.5.4.42" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri"><ns1:AttributeValue xmlns:xs="http://www.w3.org/2001/XMLSchema" xsi:type="xs:string">Derek</ns1:AttributeValue></ns1:Attribute><ns1:Attribute FriendlyName="surName" Name="urn:oid:2.5.4.4" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri"><ns1:AttributeValue xmlns:xs="http://www.w3.org/2001/XMLSchema" xsi:type="xs:string">Jeter</ns1:AttributeValue></ns1:Attribute><ns1:Attribute FriendlyName="title" Name="urn:oid:2.5.4.12" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri"><ns1:AttributeValue xmlns:xs="http://www.w3.org/2001/XMLSchema" xsi:type="xs:string">shortstop</ns1:AttributeValue></ns1:Attribute></ns1:AttributeStatement></ns1:Assertion> ++<XSW_ATTACK> ++<ns1:Assertion ID="id-Aa9IWfDxJVIX6GQye" IssueInstant="2019-12-20T12:15:16Z" Version="2.0"><ns1:Issuer Format="urn:oasis:names:tc:SAML:2.0:nameid-format:entity">urn:mace:example.com:saml:roland:idp</ns1:Issuer><ns1:Subject><ns1:NameID Format="urn:oasis:names:tc:SAML:2.0:nameid-format:transient" NameQualifier="" SPNameQualifier="id12">ac5b22bb8eac4a26ed07a55432a0fe0da243f6e911aa614cff402c44d7cdec36</ns1:NameID><ns1:SubjectConfirmation Method="urn:oasis:names:tc:SAML:2.0:cm:bearer"><ns1:SubjectConfirmationData InResponseTo="id12" NotOnOrAfter="2019-12-20T12:20:16Z" Recipient="http://lingon.catalogix.se:8087/"/></ns1:SubjectConfirmation></ns1:Subject><ns1:Conditions NotBefore="2019-12-20T12:15:16Z" NotOnOrAfter="2019-12-20T12:20:16Z"><ns1:AudienceRestriction><ns1:Audience>urn:mace:example.com:saml:roland:sp</ns1:Audience></ns1:AudienceRestriction></ns1:Conditions><ns1:AuthnStatement AuthnInstant="2019-12-20T12:15:16Z" SessionIndex="id-eEhNCc5BSiesVOl8B"><ns1:AuthnContext><ns1:AuthnContextClassRef>urn:oasis:names:tc:SAML:2.0:ac:classes:InternetProtocolPassword</ns1:AuthnContextClassRef><ns1:AuthenticatingAuthority>http://www.example.com/login</ns1:AuthenticatingAuthority></ns1:AuthnContext></ns1:AuthnStatement><ns1:AttributeStatement><ns1:Attribute FriendlyName="eduPersonAffiliation" Name="urn:oid:1.3.6.1.4.1.5923.1.1.1.1" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri"><ns1:AttributeValue xmlns:xs="http://www.w3.org/2001/XMLSchema" xsi:type="xs:string">staff</ns1:AttributeValue><ns1:AttributeValue xmlns:xs="http://www.w3.org/2001/XMLSchema" xsi:type="xs:string">member</ns1:AttributeValue></ns1:Attribute><ns1:Attribute FriendlyName="mail" Name="urn:oid:0.9.2342.19200300.100.1.3" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri"><ns1:AttributeValue xmlns:xs="http://www.w3.org/2001/XMLSchema" xsi:type="xs:string">foo@gmail.com</ns1:AttributeValue></ns1:Attribute><ns1:Attribute FriendlyName="givenName" Name="urn:oid:2.5.4.42" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri"><ns1:AttributeValue xmlns:xs="http://www.w3.org/2001/XMLSchema" xsi:type="xs:string">Derek</ns1:AttributeValue></ns1:Attribute><ns1:Attribute FriendlyName="surName" Name="urn:oid:2.5.4.4" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri"><ns1:AttributeValue xmlns:xs="http://www.w3.org/2001/XMLSchema" xsi:type="xs:string">Jeter</ns1:AttributeValue></ns1:Attribute><ns1:Attribute FriendlyName="title" Name="urn:oid:2.5.4.12" NameFormat="urn:oasis:names:tc:SAML:2.0:attrname-format:uri"><ns1:AttributeValue xmlns:xs="http://www.w3.org/2001/XMLSchema" xsi:type="xs:string">shortstop</ns1:AttributeValue></ns1:Attribute></ns1:AttributeStatement></ns1:Assertion> ++</XSW_ATTACK> ++</ns0:Response> +diff --git a/tests/test_xsw.py b/tests/test_xsw.py +new file mode 100644 +index 00000000..9978c4d3 +--- /dev/null ++++ b/tests/test_xsw.py +@@ -0,0 +1,44 @@ ++from datetime import datetime ++from unittest.mock import Mock ++from unittest.mock import patch ++ ++from saml2.config import config_factory ++from saml2.response import authn_response ++from saml2.sigver import SignatureError ++ ++from dateutil import parser ++ ++from pytest import raises ++ ++from pathutils import dotname ++from pathutils import full_path ++ ++ ++XML_RESPONSE_XSW = full_path("saml2_response_xsw.xml") ++ ++ ++class TestAuthnResponse: ++ def setup_class(self): ++ self.conf = config_factory("sp", dotname("server_conf")) ++ self.ar = authn_response(self.conf, "http://lingon.catalogix.se:8087/") ++ ++ @patch('saml2.response.validate_on_or_after', return_value=True) ++ def test_verify_signed_xsw(self, mock_validate_on_or_after): ++ self.ar.issue_instant_ok = Mock(return_value=True) ++ ++ with open(XML_RESPONSE_XSW) as fp: ++ xml_response = fp.read() ++ ++ self.ar.outstanding_queries = {"id12": "http://localhost:8088/sso"} ++ self.ar.timeslack = 10000 ++ self.ar.loads(xml_response, decode=False) ++ ++ assert self.ar.came_from == 'http://localhost:8088/sso' ++ assert self.ar.session_id() == "id12" ++ assert self.ar.issuer() == 'urn:mace:example.com:saml:roland:idp' ++ ++ with raises(SignatureError): ++ self.ar.verify() ++ ++ assert self.ar.ava is None ++ assert self.ar.name_id is None |