The right place to file this bz is upstream of gnome-shell or gdm.

The noise texture is not really a themeable part of the login screen.

The login screen is getting a redesign that will dramatically effect how the background is displayed in the future.

At that point, hopefully, Scientific Linux will no longer want to patch this. I don't have a specific timeline on
when that feature will be incorporated into Red Hat Enterprise Linux 8.

In the interim, though, we're unlikely to make changes to accommodate this sort of cosmetic reworking of the login screen.

Also relevant https://lwn.net/Articles/786422/

I'm reopening this RFE on a request from another customer. Details are below.

- Proposed title of this feature request  

Display of classification level on login screen
  
- What is the nature and description of the request?  

To allow a persistent, configuration-file-based option to display a classification notification/banner before any input occurs.

- Why does the customer need this? (List the business requirements here)  

Government security (STIG-type) documents often /usually require the security-classification level of the RHEL system to be prominently displayed on BOTH the initial login screen (before someone logs in), as well as the desktop background after the user logs in.
  
- How would the customer like to achieve this? (List the functional requirements here)  

A variety of ways are acceptable, but the solution must be persistent, and not require "extreme" measures by the customer (such as recompiling). The dconf-based configuration file method that allows for a customer-created custom background to be displayed on the (post-login) desktop, would be a fine way to accomplish the similar task of displaying a customer-created custom background that appears behind the initial login screen prompt for their username/password. Alternatively, a text-based classification banner superimposed on the screen akin to Frank Caviggia's classification banner program (https://github.com/fcaviggia/classification-banner) may also be acceptable, as long as it displays on all monitors attached to the system. (NOTE: This login-screen background must not supercede the ability to also put a custom 'banner' (text message) next to the login prompt).
  
- For each functional requirement listed, specify how Red Hat and the customer can test to confirm the requirement is successfully implemented.  

Simple test.  a) the custom background or classification banner appears behind the login screen every time it is displayed  b) any custom banner text is also successfully displayed every time the login screen is displayed  c) the solution is persistent (not altered/broken by patches/upgrades)
  
- Is there already an existing RFE upstream or in Red Hat Bugzilla?

None present at time of writing, save this one.
  
- Does the customer have any specific timeline dependencies and which release would they like to target (i.e. RHEL5, RHEL6)?  

RHEL7. We have an immediate need to accomplish this security-classification-level background on the initial login screen, in a handful of classified environments.

- Is the sales team involved in this request and do they have any additional input?  
 
Sales is not involved.

- List any affected packages or components.  

  - gdm
  - gnome-shell
  
- Would the customer be able to assist in testing this functionality if implemented?

Yes.

Using the reproducer in #c33, I was able to apply a message at the login screen depicting the security level of the system. The message was present without any interaction with the user.

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory (Moderate: GNOME security, bug fix, and enhancement update), and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2021:4381