Timeline for Drop Process Privileges

6 events

when toggle format	what		by	license	comment
Feb 22, 2013 at 22:41	comment	added	Nicholas Wilson		@David Actually, `setuid()` does set real and saved userids; you may be thinking of `seteuid()`. Not all systems have `setreuid()`, so it can't be used quite everywhere. The exact semantics of `setuid()` are compliced, but if you have euid 0, you will be able to drop all traditional user-id privileges with `setuid()`. The biggest omission in this answer is that `initgroups` or `setgroups` must be called as well as `setgid` and `setuid`, and that more thorough assertions should be done at the end.
Sep 23, 2011 at 23:01	comment	added	David Schwartz		If you're going to simplify security-critical code, you have to make it very clear that this is what you're doing. And you should say things like "it's just a matter of" when it isn't.
Sep 23, 2011 at 17:58	comment	added	tylerl		@David Schwartz code was intentionally simplified to show the mechanism used.
Sep 23, 2011 at 10:35	comment	added	David Schwartz		Note that this allows the process to recover the privileges if it wishes to! The `setuid` function only sets the effective UID, not the real UID. You should use `setreuid` if you don't want the process to be able to get the privileges back. (And the code above doesn't deal with supplementary group privileges either. It's suitable only for launching mostly-trusted code.)
Sep 23, 2011 at 9:23	history	edited	tylerl	CC BY-SA 3.0	edited body
Sep 23, 2011 at 9:17	history	answered	tylerl	CC BY-SA 3.0