FFC-DH Peer Validation Uses Attacker-Supplied q

Issue summary: When EVPPKEYderivesetpeer is called with a DHX X9.42 peer key, the peer key is not properly checked for the subgroup membership. Impact summary: A malicious peer which presents an X9.42 key carrying the victim’s p and g parameters, a forged q = r a small prime factor of the cofacto...