De-escalate to an unprivileged users during 'make build' and 'make release'.

- If you start make build as root, everything will be run as root.
  Nothing new here. New is, that you can set BUILDUSER=somebody and the
  unprived parts will be run as somebody.
- If you start make build with sudo, the unprived parts will be run as
  the real user (meaning YOU). You can still set BUILDUSER=somebody and
  the uprived parts will run as somebody.
- If you start make build as a normal user it will error out. "I'm sorry
  Dave."

Note that DESTDIR must be on partition with the noperm flag set for make
release to work correctly as an unprivileged user.

idea and ok deraadt
input and ok tb ratchov millert
rpe, halex and probably others where part of the conversation to make
this happen, thanks!

1 files changed, 3 insertions, 1 deletions

diff --git a/share/mk/bsd.own.mk b/share/mk/bsd.own.mk
index 36fa4027a90..82d33d688f4 100644
--- a/share/mk/bsd.own.mk
+++ b/share/mk/bsd.own.mk
@@ -1,4 +1,4 @@
-#	$OpenBSD: bsd.own.mk,v 1.179 2016/09/21 18:27:55 natano Exp $
+#	$OpenBSD: bsd.own.mk,v 1.180 2016/10/05 18:00:41 natano Exp $
 #	$NetBSD: bsd.own.mk,v 1.24 1996/04/13 02:08:09 thorpej Exp $
 
 # Host-specific overrides
@@ -128,6 +128,8 @@ DEFAULT_PIE_DEF=-DPIE_DEFAULT=1
 NOPROFILE=
 .endif
 
+BUILDUSER?= ${USER}
+
 BSD_OWN_MK=Done
 
 .PHONY: spell clean cleandir obj manpages print all \