This adds support for RSASSA-PSS signatures in handshake messages as
required by TLS 1.3. Even if TLS 1.2 is negotiated, it must support PSS
when advertised in the Client Hello (this will be done later as the
testdata will change).
Updates #9671
Change-Id: I8006b92e017453ae408c153233ce5ccef99b5c3f
Reviewed-on: https://go-review.googlesource.com/79736
Reviewed-by: Filippo Valsorda <filippo@golang.org>
ServerKeyExchange and CertificateVerify can share the same logic for
picking a signature algorithm (based on the certificate public key and
advertised algorithms), selecting a hash algorithm (depending on TLS
version) and signature verification.
Refactor the code to achieve code reuse, have common error checking
(especially for intersecting supported signature algorithms) and to
prepare for addition of new signature algorithms. Code should be easier
to read since version-dependent logic is concentrated at one place.
Change-Id: I978dec3815d28e33c3cfbc85f0c704b1894c25a3
Reviewed-on: https://go-review.googlesource.com/79735
Reviewed-by: Filippo Valsorda <filippo@golang.org>
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
