Fix priviledge for passwd (#75)

Signed-off-by: fxiang1 <[email protected]>

Author: fxiang1

build/bin/user_setup

@@ -2,12 +2,10 @@
 set -x
 
 # ensure $HOME exists and is accessible by group 0 (we don't know what the runtime UID will be)
-mkdir -p ${HOME}
-chown ${USER_UID}:0 ${HOME}
-chmod ug+rwx ${HOME}
-
-# runtime user will need to be able to self-insert in /etc/passwd
-chmod g+rw /etc/passwd
+echo "${USER_NAME}:x:${USER_UID}:0:${USER_NAME} user:${HOME}:/sbin/nologin" >> /etc/passwd
+mkdir -p "${HOME}"
+chown "${USER_UID}:0" "${HOME}"
+chmod ug+rwx "${HOME}"
 
 # no need for this script to remain in the image after running
 rm $0