F42 Change Proposal: dropping Of cert.pem file (system-wide)

[Aoife Moloney]

Wiki - https://fedoraproject.org/wiki/Changes/dropingOfCertPemFile
Discussion Thread -
https://discussion.fedoraproject.org/t/f42-change-proposal-dropping-of-cert-...

This is a proposed Change for Fedora Linux.
This document represents a proposed Change. As part of the Changes
process, proposals are publicly announced in order to receive
community feedback. This proposal will only be implemented if approved
by the Fedora Engineering Steering Committee.

== Summary ==
In order to increase the performance of OpenSSL by default using
directory-hash format we need to drop the /etc/pki/tls/cert.pem file
to prevent it from being loaded by default. This also includes the
certificate bundles in /etc/pki/tls/certs/ folder(ca-certificates.crt,
ca-bundle.crt).

== Owner ==
* Name: [[User:Fkrenzel| František Krenželok]]
* Email: [e-mail]

== Detailed Description ==
In order to improve the loading time of OpenSSL, a directory-hash
support was added to ca-certificates. In order for OpenSSL to use the
directory-hash format by default we need to stop it from trying to
load /etc/pki/tls/cert.pem by deleting it. This also applies to the
certificate bundles in /etc/pki/tls/certs/ folder(ca-certificates.crt,
ca-bundle.crt).

== Feedback ==
=== (a) Changing the OpenSSL configuration directory (OPENSSLDIR) ===

Automated tools often rely on the output of openssl version -d to
infer locations such as <OPENSSLDIR>/'''openssl.cnf''' as the
configuration file.
Changing OPENSSLDIR risks breaking these assumptions and complicating
integrations.

A possible solution could be changing the directory to something like
/usr/lib/openssl/ and shipping a symlink, e.g.,
`/usr/lib/openssl/openssl.cnf -> /etc/pki/tls/openssl.cnf.` However,
this is less than ideal.

=== (b) Patching the OpenSSL source code ===
This approach involves patching OpenSSL to use directories outside of
the OPENSSLDIR/certs default for the root certificates.

Although it avoids relocating the configuration file.
It introduces a downstream patch that would need to be maintained
indefinitely(There are already loads of patches and the maintainers
really dislike this idea).
Such a patch would also be unexpected behavior for users accustomed to
upstream defaults.

This was partly discussed here:
https://lists.fedoraproject.org/archives/list/[e-mail]/...

Note: Option (a) is gravely discouraged. Option (b) could be
implemented instead, but it still has drawbacks, including potentially
unforeseen ones.

== Benefit to Fedora ==
Applications using OpenSSL(possibly other libraries as well) will
benefit from much faster initialization of OpenSSL.

== Scope ==
* Other developers:
Any package loading the root certificates from any of the following bundles:

`/etc/pki/tls/cert.pem`

`/etc/pki/tls/certs/ca-certificates.crt`

`/etc/pki/tls/ca-bundle.crt`

needs to preferably use the defaults of the library or if they must,
use the `/etc/pki/ca-trust/extracted/pem/tls-ca-bundle.pem` file
instead.

* Release engineering: [https://pagure.io/releng/issues #Releng issue
number] <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
* Policies and guidelines: N/A (not needed for this Change)
* Trademark approval: N/A (not needed for this Change)
* Alignment with the Fedora Strategy: neither does nor doesn't

== Upgrade/compatibility impact ==
Once this change is integrated, the packages/software using any of the
following files `/etc/pki/tls/cert.pem`
`/etc/pki/tls/certs/ca-certificates.crt` `/etc/pki/tls/ca-bundle.crt`
as a root certificate bundle file might encounter connectivity issues.

== How To Test ==
Target behavior: OpenSSL initialization takes less time when the file
isn't present compared to it being there.

1. The following will create a symlink for testing after the change
has been integrated(i.e. the `.../tls/cert.pem` file is missing)

`ln -s /etc/pki/ca-trust/extracted/pem/tls-ca-bundle.pem /etc/pki/tls/cert.pem`

2. Test the time of OpenSSL initialization or a package using it with
and without the aforementioned symlink.
(If there is no difference for package then it is most likely due to
OpenSSL not being configured to search for certs in default location)

== User Experience ==
Packages using a OpenSSL will have faster initialization time.

== Dependencies ==
Any package using
`/etc/pki/tls/cert.pem`,`/etc/pki/tls/certs/ca-certificates.crt` or
`/etc/pki/tls/ca-bundle.crt` file are affected. It is required that
the maintainers change this so that user experience is not
compromised.

== Contingency Plan ==
* Contingency mechanism: We will postpone the change if majority or
critical package owners will be unable to make appropriate changes.
* Contingency deadline: before end of beta freeze(2025-02-18).
* Blocks release? The feature doesn't block release.

== Documentation ==

The change is documented as a part of ca-certificates package changelog.

== Release Notes ==
The /etc/pki/tls/cert.pem certificate file has been Removed.

[Aoife Moloney]

Please ignore this change announcement, I was looking at the wrong list (d'oh) :-/

This change has already been announced and is with FESCo for decision https://pagure.io/fesco/issue/3293