When we are doing PSK, we'd like to set verify_result to
MBEDTLS_X509_BADCERT_SKIP_VERIFY. Previously this was done in
mbedtls_ssl_set_hs_psk() but this is inadequate since this function may
be called for early data (where certificate verification happens later
in the handshake.
Instead, set this value after writing / processing the encrypted
extensions on the server / client respectively, so that we know whether
we are doing certificate verification or not for sure. This change is
effective only for TLS 1.3 as TLS 1.2 sets verify_result for PSK in
ssl_parse_certificate_coordinate().
Signed-off-by: David Horstmann <david.horstmann@arm.com>
624fc2e0de