System Programming: Can D binaries be set suid root without the risk of unwanted privilege escalation?

[Forum User]

On Monday, 16 February 2026 at 01:24:59 UTC, Julian Fondren wrote:

Thanks for the thorough answers and the link.

> [..] For example, suppose you have a setuid program that edits 
> /home/$user/somedir/somefile . If you do this straightforwardly 
> in D you open yourself up to a ton of potential race conditions 
> that can result in you editing or deleting random files across 
> the filesystem, or pulling secrets and exposing them to the 
> user.

Such access I would usually perform with the effective user and 
effective group set to $user (`seteuid`, `setegid`). For some 
edge cases the supplementary groups must also be set (assume a 
`root:video` owned file `data` has permissions `0704` and assume 
the accessing user either has or has not `video` in its 
supplementary groups list: In the first case they cannot access 
`data` while in the second they can via `o=r` permission.)