Comment by gbrown_

I'm just going to dump some other links to pledge just for others that are interested. Here's some presentations on attempts at natively implementing pledge in Linux (YouTube's auto-translate does a decent job) [1][2].

The topic of a pledged process starting other processes un-pledged often comes up (and already has done in the comments here). I'd recommend checking out this section of Theo de Raadt's presentation that explains why this is [3].

As mentioned in the article the nice thing of pledge on OpenBSD is the integration of the pledge interface with the reality of underlying system. So as one example a program can pledge only dns and say not have filesystem access, but really under the covers it can read /etc/resolv.conf.

[1]https://www.youtube.com/watch?v=uXgxMDglxVM

[2] https://www.youtube.com/watch?v=PK7gETZURx0

[3] https://youtu.be/Er44ur7wkXQ?t=1497