Missing some standard certificate extensions

[lilyball]

This crate parses most standard certificate extensions defined in RFC 5280, but it seems to be missing the following:

Certificate Extensions:

• Issuer Alternative Name (§4.2.1.7)
• Subject Directory Attributes (§4.2.1.8)
• CRL Distribution Points (§4.2.1.13)
• Freshest CRL (a.k.a. Delta CRL Distribution Point) (§4.2.1.15)

It's also missing some CRL and CRL Entry extensions:

• Delta CRL Indicator (§5.2.4)
• Issuing Distribution Point(§5.2.5)
• Certificate Issuer (§5.3.3)

I don't know how much the CRL ones matter, though this crate does support 3 such CRL/CRL Entry extensions already (plus the ones that are identical to certificate extensions).

[lilyball]

@chifflier Freshest CRL (OID_X509_EXT_FRESHEST_CRL) uses the same Distribution Points type

FreshestCRL ::= CRLDistributionPoints

So it should be pretty trivial to add that to the set of parsed extensions.

[cpu]

Issuing Distribution Point(§5.2.5)

I've implemented support for this CRL extension in #146

[lilyball]

The implemented IssuingDistributionPoint type does not conform to FromDer, which is unfortunate as it means the extension cannot be parsed later on if X509CertificateParser is configured to disable deep-parsing extensions.

This is also true of some other extensions available in 0.17.0, such as PolicyInformation (for CertificatePolicies), ReasonCode, and SignedCertificateTimestamp. There's also some other defined structs in x509_parser::extensions that don't have FromDer impls such as GeneralSubtree and DistributionPointName.

[chifflier]

The implemented IssuingDistributionPoint type does not conform to FromDer, which is unfortunate as it means the extension cannot be parsed later on if X509CertificateParser is configured to disable deep-parsing extensions.

Hi,
This was true until the rewrite (#207). In the current master, issuing_distribution_point implements DerParser (thanks to automatic Sequence derive)

This is also true of some other extensions available in 0.17.0, such as PolicyInformation (for CertificatePolicies), ReasonCode, and SignedCertificateTimestamp. There's also some other defined structs in x509_parser::extensions that don't have FromDer impls such as GeneralSubtree and DistributionPointName.

These should now also implement traits.
Please note that this is all implemented for the next release. Given the amount of changes, there will be a alpha/beta phase before stable release.