Re: Support for NSS as a libpq TLS backend

On Mon, 2020-07-20 at 15:35 +0200, Daniel Gustafsson wrote:
> With this, I have one failing test ("intermediate client certificate is
> provided by client") which I've left failing since I believe the case should be
> supported by NSS. The issue is most likely that I havent figured out the right
> certinfo incantation to make it so (Mozilla hasn't strained themselves when
> writing documentation for this toolchain, or any part of NSS for that matter).

I think we're missing a counterpart to this piece of the OpenSSL
implementation, in be_tls_init():

if (ssl_ca_file[0])
{
...
SSL_CTX_set_client_CA_list(context, root_cert_list);
}

I think the NSS equivalent to SSL_CTX_set_client_CA_list() is probably
SSL_SetTrustAnchors() (which isn't called out in the online NSS docs,
as far as I can see).

What I'm less sure of is how we want the NSS counterpart to ssl_ca_file
to behave. The OpenSSL implementation allows a list of CA names to be
sent. Should the NSS side take a list of CA cert nicknames? a list of
Subjects? something else?

mod_nss for httpd had a proposed feature [1] to do this that
unfortunately withered on the vine, and Google returns ~500 results for
"SSL_SetTrustAnchors", so I'm unaware of any prior art in the wild...

--Jacob

[1] https://bugzilla.redhat.com/show_bug.cgi?id=719401