Golang-fips/openssl: memory leaks in code encrypting and decrypting rsa payloads

A memory leak flaw was found in Golang in the RSA encrypting/decrypting code, which might lead to a resource exhaustion vulnerability using attacker-controlled inputs​. The memory leak happens in github.com/golang-fips/openssl/openssl/rsa.go#L113. The objects leaked are pkey​ and ctx​. That function uses named return parameters to free pkey​ and ctx​ if there is an error initializing the context or setting the different properties. All return statements related to error cases follow the "return nil, nil, fail(...)" pattern, meaning that pkey​ and ctx​ will be nil inside the deferred function that should free them.