BlackListedLeaf is not handled by X509 PAL on macOS

[vcsjones]

Yes, the name is unfortunate.

While working on #35347 I started investigating other statuses that are not handled correctly by the macOS chain PAL and will result in a CryptographicException when attempting to build the chain.

If you attempt to build an X509Chain with the following certificate, it will lead to a CryptographicException.

var cert = @"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";
var leafCert = new X509Certificate2(Convert.FromBase64String(cert));
X509Chain chain = new X509Chain();
chain.Build(leafCert);

There are a handful of certificates that Apple has hard-coded as bad, based on their issuer/serial pairing.

I think it would make sense to mark these as PAL_X509ChainRevoked or PAL_X509ChainExplicitDistrust. I do not think we should ignore the status like we do for grey listed items.

@bartonjs what is your opinion on how this status should be handled?

Tagging subscribers to this area: @bartonjs, @vcsjones, @krwq
Notify danmosemsft if you want to be subscribed.

[filipnavara]

There's also BlackListedKey which should likely get the same treatment.

[vcsjones]

@filipnavara yep, I intend to file an issue for each status as I am able to reproduce them. I think there are about a half dozen more that a user could possibly hit. There are others that would be harder to write tests for and reproduce, and would require a certificate from a CA that violates the CAB Baseline Requirements (a manually trusted root is not enough).

[vcsjones]

what is your opinion on how this status should be handled?

I suppose the first question is going to be "what do other platforms do?". I'll investigate soon.

[vcsjones]

This reproduces "BlackListedKey"

var intermediate = @"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";
var cert = @"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";
var leafCert = new X509Certificate2(Convert.FromBase64String(cert));
var intermediateCert = new X509Certificate2(Convert.FromBase64String(intermediate));
X509Chain chain = new X509Chain();
chain.ChainPolicy.ExtraStore.Add(intermediateCert);
chain.Build(leafCert);

[vcsjones]

For context: BlackListedKey is a status on intermediate certificates when building a leaf against the intermediate which also uses a banned SPKI.