[Kaldesyvon]

Summary

Many System.Security.Cryptography calls name an algorithm but leave the details to
neighboring namespaces: the hash and padding of a certificate signature, the cipher and
iteration count that protect an exported key, the URI that names an XML signature algorithm.
Until now the plugin saw none of that. This adds detection rules for those namespaces so the
CBOM records the details as well as the algorithm name.

What is detected

Namespace	Calls	Reported as
X509Certificates	new CertificateRequest(...), X509SignatureGenerator.CreateForRSA/CreateForECDsa	Sign with hash and, for RSA, padding
X509Certificates	GetCertHash, GetCertHashString, TryGetCertHash (the no-argument forms are the SHA-1 thumbprint)	digest
System.Security.Cryptography	new PbeParameters(cipher, hash, iterations), ExportPkcs12(Pkcs12ExportPbeParameters.X, ...)	PBES2 or PKCS#12 scheme with cipher, hash, iteration count
Pkcs	Pkcs12Builder.SealWithMac, Rfc3161TimestampRequest.CreateFromData/Hash/SignerInfo	HMAC with hash and iterations; digest
Xml	Reference.DigestMethod, SignedInfo.SignatureMethod (including the chained form), new EncryptionMethod(...), KeyAlgorithm	digest, signature or HMAC, cipher or key transport
Cose	new CoseSigner(...)	Sign with hash and, for RSA, padding

Engine changes (shared code from #559)

1. Chained property assignments (CSharpTreeConverter): a.b.c = value is now converted to
   a set_c setter whose receiver is the whole chain (a.b). That text never equals a
   variable name, so setters attached to a tracked variable ignore it
   (rsa.Options.KeySize = 1 does not change rsa). Chains with an index or a
   null-conditional are still ignored. This is what makes the usual
   signedXml.SignedInfo.SignatureMethod = … visible.
2. Argument type check (CSharpTypeInference): two different enum or struct types, such as
   RSASignaturePadding and HashAlgorithmName, are now treated as incompatible. Without
   this, CoseSigner(key, padding, hash) bound the padding to the hash parameter. Class
   types (RSA, AsymmetricAlgorithm, …) are left out on purpose because they can be
   subtypes.

Tests

• 10 new test classes: one per rule set, one for the chained setter, and unit tests for the two
  lookup tables and the type check.
• Absence is asserted for unresolvable values (unknown hash, unknown iteration count,
  unknown URI, Pkcs12ExportPbeParameters.Default).

Known limits

• A certificate request is not linked to the key that feeds it; they are separate findings.
• CmsRecipient is not covered: its overloads move the padding argument between positions.
• A constant reached through a class (Cfg.Rounds) is not resolved for integer parameters.

[Kaldesyvon]

Hello maintainers

I have created PR for extending Crypto namespace crypto algorithms. Please review it. I will be not available whole next week.

Thank you very much

[fynnth]

Hi Martin,

I have looked at the code and the detection worked well, but there was the issue that the root detection node was the signing operation, which meant that it was not processed further after the detection and it was not able to create the issue and put it in the cbom. So i tried to reverse the detection a bit and detect RSA/ECDSA as the root with the hash and signing operation beneath it. This is just a proposal so lets look at it together next week and talk about it :)

Best regrads,
fynn