Why are you changing trust settings?
Adding an SSL certificate to the machine for secure communication.
Running a process as "root" requires authentication by the OS, making it redundant. But to the OP's point, this prompt seems to mismatch the documentation, which clearly indicates that no further action is required, quoting it again:
"[...] When making changes to system-wide trust settings, the user is prompted with an alert panel asking for an administrator’s name and password unless the calling process is running as root, in which case no further authentication is needed. [...]
The documentation warns that this can and will block, quoting:
"[...] Note that this function might block while waiting for user input. [...]
... so I find the OP's question to be valid.
It sounds like you’re under the misapprehension that “running … as root” is the same as “Administrator privileges”.
I'm having a hard time understanding where this assumption was drawn from, the OP clearly says "root". XCode calls this root:
Product > Scheme > Edit Scheme > Debug process as root
Changing trust settings requires user interaction regardless of the BSD level privileges of your process.
I'm having a hard time understanding if this is suggesting that the documentation is outdated, or if the Scheme is not doing as described?
In general this is not a happy path to be going down.
Reading between the lines, I think there's some assumption that modifying the SSL trust settings is bad practice. This is both presumptuous as well as untrusting. In my use-case, myself and my company have been vetted by Apple through Dun & Bradstreet. Each application distributed undergoes notarization and stapling by Apple, however there are use-cases where this User Interaction blocks similarly as documented (but even when running as root). I think the OP's question as well as the quoted documentation have merit and as a result promote happiness. :)
More strictly speaking, self-signed certificates are arguably more secure than CA-issued certificates because the chain of trust does not imply monolith issuers. Furthemore, when done properly, private key leakage will only impact a single machine.
I understand there are some cases where self-signed certificates are lazily installed (e.g. SuperFish / Lenovo) and those concerns have merit as well, but then this turns more into a conversation about the dangers in self-signed certificate (e.g. wildcard and/or non-owned FQDN and/or non-localhost) scope, rather than about security in general. Furthemore, in the event of the SuperFish / Lenovo disaster, it was the worldwide private-key sharing across all devices that made the scope so terrifying. Perhaps this behavior should be fingerprinted and added as a blocker to the notarization process, since I've seen other apps (e.g. Cricut) continue this practice years after that fiasco. :(
Oddly, Apple does have a plist flag for suppressing this prompt, but this technique seems like using a sledgehammer to crack a nut, and due to how contradictory this appears from a security perspective, can be presumed will be removed in a future OS update.
