Replace the shelled out openssl pem to der conversion, in favor of l…

[cleblanc87]

…ua-resty-core conversion method cert_pem_to_der, this will now preserve the full certificate chain

[cleblanc87]

Fixes #872.

Started in on adding tests, but importing "ngx.ssl" breaks the tests with
/usr/local/share/lua/5.1/ngx/ssl.lua:5: module 'resty.core.base' not found:No LuaRocks module found for resty.core.base

I am not too familiar with this ecosystem, so a nudge in the right direction would be very welcome :)

[thibaultcha]

This error occurs because in spec/plugins/ssl/access_spec.lua, the kong.plugins.ssl.ssl_util module is being unit tested, so it is required here. Because this does not run inside Nginx, resty.core.base is not in the LUA_PATH.

iirc, this is the reason why the module is required inside the functions, such as here, so they can be required while unit testing. I am not a fan of this solution, I think a patch that properly requires ngx.ssl at module-level for this plugin (and removing the unit tests in access_spec.lua) would be an improvement. Do you want some time to update yours?

[subnetmarco]

Looking forward to see a test for this, so we can close the issue.

[subnetmarco]

By the way it seems like the new version of OpenResty is also going to ship with priv_key_pem_to_der which will allow us to never use OpenSSL for both conversions (key/cert to DER).

Also, https://github.com/openresty/lua-resty-core/blob/master/lib/ngx/ssl.md#priv_key_pem_to_der

[subnetmarco]

Fixed with #968.