A Lua module that provides setuid and chroot functionality.

Requirements

lua >= 5.1

Usage

setuid.setuid( username ): Change the current process user ID (real, effective, saved) to that of username.

setuid.chroot( path, username ): chroot into path. If username is not nil, then change the current process user ID to that of username.

We need setuid.chroot to optionally accept a username for changing the user ID after chrooting since getpwnam is reading password file entries behind the scenes. We need to obtain the target user ID before chrooting, however we require root to chroot so we need to actually set the user ID afterwards.

Example

local setuid = require( "setuid" )

-- in a real program you can only do one of these
assert( setuid.chroot( "src", "notroot" ) )
assert( setuid.chroot( "src" ) )
assert( setuid.setuid( "notroot" ) )