How do I list all available SSL CA certificates on CentOS 6?

Question

It's difficult to tell whether I've succeeded in trusting a given certificate, after I have installed it, especially for root CAs.

To check whether I have successfully installed a certificate without making an SSL request to a server that may or may not provide it, I would like to list of all system wide available ssl certificates.

I followed the instructions here, and they worked:

https://serverfault.com/questions/559571/install-a-root-certificate-in-centos-6

Also, this asks a similar question, but gives an answer for gentoo systems:

List all available ssl ca certificates

Answer 1

// , Use the openssl command to get output from /etc/ssl/certs/ca-bundle.crt

Anyway, I tried the following, mostly copied from https://unix.stackexchange.com/a/97249/48498, and it seemed to work if I changed the filename to account for CentOS 6:

If you don't want to have to bother with the --insecure flag or its analogues on cURL, wget, Git, etc, you can add a CA root certificate, self-signed certificate, or certificate chain to your trust store as follows:

1. Follow the instructions to download the .crt, .pem, or .cer of your choice.

2. Obtain the certificate you want to trust through whatever mechanism you use, often by downloading it from a central repository or by extracting it from an SSL handshake with openssl s_client -showcerts -connect some.host.that.uses.that.root:443, or such, and copy it to the following folder on the target CentOS 6 host:

    /etc/pki/ca-trust/source/anchors/

Run the following commands while logged in to the target host:

    $ sudo update-ca-trust enable; sudo update-ca-trust extract

Verify the results on the Red Hat based OS, e.g.:

    $ awk -v cmd='openssl x509 -noout -subject' '
        /BEGIN/{close(cmd)};{print | cmd}' < /etc/ssl/certs/ca-bundle.crt

This should yield a long list of responses of the form:

    subject= /C=US/O=MyCorp/CN=root-ca-2048

Step #4 in the above answers this question, and the other steps provide context for the unwary.