Development #56023
lasso_node_encrypt / hard coded PKCS#1
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Description
I ran into a problem with LemonLDAP (as SAML IdP) when I tried to encrypt the assertion.
The SAML SP (SimpleSAMLphp in this case) wasn't able to decrypt it.
Cause is that SimpleSAMLphp blocks PKCS#1 by default:
https://simplesamlphp.org/docs/stable/simplesamlphp-reference-idp-remote#section_2 (encryption.blacklisted-algorithms)
Reason is probably the same as described here: http://shibboleth.net/pipermail/dev/2012-July/000858.html
I discovered that PKCS#1 for key encryption is hard coded in the function lasso_node_encrypt (lasso/xml/xml.c line 623/624):
encrypted_key_node = xmlSecTmplKeyInfoAddEncryptedKey(key_info_node,
xmlSecTransformRsaPkcs1Id, NULL, NULL, (xmlChar*)recipient);
If I change xmlSecTransformRsaPkcs1Id to xmlSecTransformRsaOaepId, SimpleSAMLphp happily decrypts it.
So maybe is there a change to get is configurable by a parameter?
Or some sort of logic that uses PKCS#1 for DES keys and RSA-OAEP for AES keys?
We might face this issue again in the near future when we need to add Auth0 as another SP. They probably want AES256 & RSA-OAEP:
https://auth0.com/docs/protocols/saml-protocol/saml-configuration-options/sign-and-encrypt-saml-requests#send-encrypted-saml-authentication-assertions
Fichiers
Révisions associées
Change default key encryption padding algorithm to RSA-OAEP (#56023)
The key encryption padding algorithm is now configurable, the default
being changed to OAEP. It's possible to set the default through
./configure with:
--with-default-key-encryption-method=[rsa-pkcs1|rsa-oaep]at initialization time with an environment variable:
LASSO_DEFAULT_KEY_ENCRYPTION_METHOD=[rsa-pkcs1|rsa-oaep]or at runtime for a service provider:
lasso_provider_set_key_encryption_method(LassoProvider *provider,
LassoKeyEncryptionMethod key_encryption_method)The setting is global for all encrypted nodes (Assertion or NameID).
Historique
Mis à jour par Benjamin Dauvergne il y a plus de 2 ans
- Assigné à mis à Benjamin Dauvergne
It seems mandated by the specification so I will add an abstraction named "encryption_key_encryption_type" and I will change the default to OAEP..
# in https://www.oasis-open.org/committees/download.php/35393/sstc-saml-conformance-errata-2.0-wd-04-diff.pdf 4.2 XML Encryption Algorithms XML Encryption mandates use of the following algorithms in Sections 5.2.1 and 5.2.2; therefore they MUST be implemented by compliant SAML V2.0 implementations: * Block Encryption: TRIPLE DES, AES-128, AES-256 * Key Transport: RSA-v1.5, RSA-OAEP
Mis à jour par Benjamin Dauvergne il y a plus de 2 ans
- Fichier 0002-Change-default-key-encryption-padding-algorithm-to-R.patch 0002-Change-default-key-encryption-padding-algorithm-to-R.patch ajouté
- Fichier 0001-Python-fix-formatting.patch 0001-Python-fix-formatting.patch ajouté
- Tracker changé de Support à Development
- Statut changé de Nouveau à Solution proposée
- Patch proposed changé de Non à Oui
Mis à jour par Benjamin Dauvergne il y a plus de 2 ans
- Catégorie mis à Binding python
- Assigné à changé de Benjamin Dauvergne à Stephan Schmidtmer
Could you test the given patch on your use case ?
Mis à jour par Stephan Schmidtmer il y a plus de 2 ans
Sure, I have tested it. Looks good so far!
I applied it to 2.6.0 Debian (buster) source package, just had to manually do 3 tiny hunks.
And while the changed default to OAEP already does the trick in my case, I also verified that influencing it by the environment variable or by lasso_provider_set_key_encryption_method() is working.
Will this get into the Debian stable release package (or maybe into a backports package)?
Mis à jour par Benjamin Dauvergne il y a plus de 2 ans
Stephan Schmidtmer a écrit :
Will this get into the Debian stable release package (or maybe into a backports package)?
I'm not sure, there is a policy of bugfixes only I'm not sure I could backport a bugfix from this commit; there is not really a bug, but it will to testing and integrate the backports repository easily.
Mis à jour par Stephan Schmidtmer il y a plus de 2 ans
Yes, while it can cause trouble here and there, I agree that it probably doesn’t count as a bug.
But if I can get a “fixed” version as a package from the backports repository in the near future, that would be great!
Mis à jour par Benjamin Dauvergne il y a plus de 2 ans
- Assigné à changé de Stephan Schmidtmer à Benjamin Dauvergne
Mis à jour par Benjamin Dauvergne il y a plus de 2 ans
- Statut changé de Solution proposée à Résolu (à déployer)
commit 53b0bd356982eb970581aa360d750c8a0e7132a0
Author: Benjamin Dauvergne <bdauvergne@entrouvert.com>
Date: Fri Sep 3 07:48:35 2021 +0200
Change default key encryption padding algorithm to RSA-OAEP (#56023)
The key encryption padding algorithm is now configurable, the default
being changed to OAEP. It's possible to set the default through
./configure with:
--with-default-key-encryption-method=[rsa-pkcs1|rsa-oaep]
at initialization time with an environment variable:
LASSO_DEFAULT_KEY_ENCRYPTION_METHOD=[rsa-pkcs1|rsa-oaep]
or at runtime for a service provider:
lasso_provider_set_key_encryption_method(LassoProvider *provider,
LassoKeyEncryptionMethod key_encryption_method)
The setting is global for all encrypted nodes (Assertion or NameID).
commit 1e718bd3aaa4bc203c6418d3cce0e0bc1f0d19b3
Author: Benjamin Dauvergne <bdauvergne@entrouvert.com>
Date: Fri Sep 3 11:13:49 2021 +0200
Python: fix formatting (#56023)
Python: fix formatting (#56023)