tls_parse_stoc_key_share was generating a new EVP_PKEY public/private
keypair and then overrides it with the server public key, so the
generation was a waste anyway. Instead, it should create a
parameters-only EVP_PKEY.
(This is a consequence of OpenSSL using the same type for empty key,
empty key with key type, empty key with key type + parameters, public
key, and private key. As a result, it's easy to mistakenly mix such
things up, as happened here.)
Reviewed-by: Matt Caswell <matt@openssl.org>
Reviewed-by: Kurt Roeckx <kurt@roeckx.be>
(Merged from https://github.com/openssl/openssl/pull/9445)
(cherry picked from commit 166c0b98fd)