Issue summary: Generating excessively long X9.42 DH keys or checkingexcessively long X9.42 DH keys or parameters may be very slow.Impact summary: Applications that use the functions DH_generate_key togenerate an X9.42 DH key may experience long delays. Likewise, applicationsthat use DH_check_pub_key, DH_check_pub_key_ex or EVP_PKEY_public_checkto check an X9.42 DH key or X9.42 DH parameters may experience long delays.Where the key or parameters that are being checked have been obtained froman untrusted source this may lead to a Denial of Service.While DH_check performs all the necessary checks ,DH_check_pub_key doesn't make any of these checks, and is thereforevulnerable for excessively large P and Q parameters.Likewise, while DH_generate_key performs a check for an excessively largeP, it doesn't check for an excessively large Q.An application that calls DH_generate_key or DH_check_pub_key andsupplies a key or parameters obtained from an untrusted source could bevulnerable to a Denial of Service attack.DH_generate_key and DH_check_pub_key are also called by a number ofother OpenSSL functions. An application calling any of those otherfunctions may similarly be affected. The other functions affected by thisare DH_check_pub_key_ex, EVP_PKEY_public_check, and EVP_PKEY_generate.Also vulnerable are the OpenSSL pkey command line application when using the"-pubcheck" option, as well as the OpenSSL genpkey command line application.The OpenSSL SSL/TLS implementation is not affected by this issue.The OpenSSL 3.0 and 3.1 FIPS providers are not affected by this issue