How do I add an extra signing cert to an existing gem?

Question

I've been added as a contributor to an existing project which has a signing certificate attached to the gem. I'll be pushing the next release so I need to add my cert to the gem. When I follow the instructions at http://guides.rubygems.org/security/#building-gems everything is fine up till I reach point 4 and run gem build… the following error presents itself:

ERROR: While executing gem ... (Gem::Security::Exception) invalid signing chain: certificate (my details) was not issued by (existing cert owner's details)

I've never added a second cert to an existing gem, does anyone know what the next step is? Does the existing cert owner need to do something? Is a project supposed or able to have more than one cert?

Answer 1

Presumably you self-issued your own cert, and it's complaining that the cert chain is broken as a result. The gem's owner should issue your cert using their own as the certification authority.

https://support.dnsimple.com/articles/what-is-ssl-certificate-chain/

It can be done using openssl. The docs for doing so are - unfortunately - abysmally bad and the steps you need to take to do so are hairy - to put it mildly. Possible walkthrough here.