GHSA-9qwg-crg9-m2vc: `openssl` `SubjectAlternativeName` and `ExtendedKeyUsage::other` allow arbitrary file read

SubjectAlternativeName and ExtendedKeyUsage arguments were parsed using the OpenSSL function X509V3_EXT_nconf. This function parses all input using an OpenSSL mini-language which can perform arbitrary file reads.

Thanks to David Benjamin (Google) for reporting this issue.