Right. Previously the return code from x509_verify_cert was returned directly to the caller, which was incorrect - ssl_verify_chain_cert was supposed to return

Right. Previously the return code from x509_verify_cert was returned directly to the caller, which was incorrect - ssl_verify_chain_cert was supposed to return -1 if the caller should retry, but would end up doing so on any error that was returned from x509_verify_cert. So the patch is correct. If your argument is that the return codes should be consistent across different layers of OpenSSL then I'm not going to disagree, but this is a large old codebase and this isn't some unique case.