Should the other calls to OBJ_nid2sn also be fixed?:

• pyopenssl/src/OpenSSL/crypto.py

  Line 504 in da18a74

  return cls(lib, nid, _ffi.string(lib.OBJ_nid2sn(nid)).decode("ascii"))

• pyopenssl/src/OpenSSL/crypto.py

  Line 753 in da18a74

  name = _lib.OBJ_nid2sn(nid)

• pyopenssl/src/OpenSSL/crypto.py

  Line 2607 in da18a74

  string_type = _lib.OBJ_nid2sn(nid)

Passing an undef NID to EllipticCurve.from_nid is already documented as requiring a known NID. In the UNDEF case it will fail sooner on OpenSSL 3.1.0, but that's it. (This is a terrible API in general, as is most of pyOpenSSL, but c'est la vie).

X509Name.get_components appears reachable so I'd be happy to review a patch that fixes that (and adds a test).

PKCS7.get_type_name would be reachable only if someone creates a PKCS7 structure that deliberately does not use known types. That's certainly possible, albeit somewhat involved. If a test exercising the path is created we'd take a patch for this as well.

Thanks!