I did a proof-of-concept [1] of such a system several years ago in C/Lua to allow non-root users to bind to privileged ports [2]. The things I got from this we

I did a proof-of-concept [1] of such a system several years ago in C/Lua to allow non-root users to bind to privileged ports [2]. The things I got from this were: 1) Odd that something like this hadn't been written for Unix years before as a way to avoid "set uid" programs and 2) passing FDs in Unix is a pain. 3) only Linux supports passing a PID along with the FD request (and Linux may be the only one to pass UID/GID as well, which may explain why 1 wasn't done). I don't really use that program as it's utility is limited. Shame, as I think it's a good idea but way too late to be of any use these days. [1] https://github.com/spc476/ipacld https://github.com/spc476/ipacld [2] You can see a set of "rules" in this file: https://github.com/spc476/ipacld/blob/master/ipacl.lua https://github.com/spc476/ipacld/blob/master/ipacl.lua