Add signature_algorithms_cert extension to _serverTLS13Handshake #513

Odinmylord · 2024-04-09T15:49:22Z

At the moment the _serverTLS13Handshake function does not have a simple way to generate and send the signature_algorithms_cert extension. Since the extension is not generated by OpenSSL, tlslite-ng is the easiest way I found to create a webserver that sends this extension

This change is

…" function

tomato42

Reviewed 2 of 2 files at r1, all commit messages.
Reviewable status: all files reviewed, 5 unresolved discussions (waiting on @Odinmylord)

-- commits line 2 at r1:
The point of the change is to include signature_algorithms_cert extension in the CertificateRequest, isn't it?

tlslite/handshakesettings.py line 400 at r1 (raw file):

        self.record_size_limit = 2**14 + 1  # TLS 1.3 includes content type
        # data needed for the signature algorithms cert extension
        self.more_sig_schemes_cert = []

they should have non empty default values; whether those should be the same as the ones for rsa, ecdsa, and other, or not is a separate question

tlslite/handshakesettings.py line 401 at r1 (raw file):

        # data needed for the signature algorithms cert extension
        self.more_sig_schemes_cert = []
        self.ecdsaSigHashesCert = []

camelCase is deprecated, it exists because I don't want to break API, new fields should use snake_case

tlslite/handshakesettings.py line 685 at r1 (raw file):

        other.more_sig_schemes_cert = self.more_sig_schemes_cert
        other.ecdsaSigHashesCert = self.ecdsaSigHashesCert
        other.rsaSigHashesCert = self.rsaSigHashesCert

the values need to be validated too

tlslite/tlsconnection.py line 2835 at r1 (raw file):

                cr_settings.more_sig_schemes = cr_settings.more_sig_schemes_cert
                cr_settings.ecdsaSigHashes = cr_settings.ecdsaSigHashesCert
                cr_settings.rsaSigHashes = cr_settings.rsaSigHashesCert

we definitely don't want to overwrite those values, settings object can be reused connection to connection

tomato42 · 2024-04-09T17:50:54Z

(I'm assuming you want to be able to send different contents in the _cert and non cert extensions, so I've reviewed the PR as such, if that's not your intention, and you're fine with just duplicating values between them, then we don't need changes around handshake settings)

Odinmylord

The idea is to have different values since if there is the same values, according to RFC8446, the signature_algorithms_cert extension can be omitted. Sorry for not being clear enough

Reviewable status: 0 of 2 files reviewed, 5 unresolved discussions (waiting on @tomato42)

-- commits line 2 at r1: