Christopher Zimmermann <[email protected]> wrote: > Thanks for your feedback guys. I tried to improve the interface by > calling the hook for each challenge challenge individually and send > information from acme-client via environment variables, which are > checked against a restrictive alphabet. This makes dropping privileges > easier and passing random crap from the internet harder. > > Privileges can now be dropped with this idiom: > > [ `/usr/bin/who -m |cut -d ' ' -f 1` == 'nobody' ] || > exec /usr/bin/su -s /bin/sh nobody -s "$@" <"$0"
Wow. Just wow. No way. That's the type of stuff people did in 1999. These days, we build the minimal narrow layers of communication between things, and we don't throw a shell script in there that uses "nobody" as a safe UID (it is not a safe UID).
