Update dockerfile

ping-service/Dockerfile

@@ -1,7 +1,7 @@
 # Use ubuntu 16.04
 FROM ubuntu:16.04
 
-RUN apt-get update && apt-get -y dist-upgrade --fix-missing --fix-broken
+RUN apt-get update --fix-missing && apt-get -y dist-upgrade --fix-missing --fix-broken
 
 # install socat editor ssh
 RUN apt-get install curl netcat-openbsd vim nano openssh-server socat lib32ncurses5 python python-pip python-dev iputils-ping -y
@@ -21,6 +21,7 @@ RUN echo 'alias kill="echo no kill please!"' >> ~/.bashrc
 RUN chmod 700 /usr/bin/* /bin/* /dev/shm
 RUN chmod 755 /usr/bin/env /bin/dash /bin/bash /bin/sh /bin/nc /bin/cat /usr/bin/curl /usr/bin/groups /usr/bin/id /bin/ls /usr/bin/python /bin/ping
 
+RUN chmod 4755 /usr/local/bin/ping
 
 RUN chown root:ksl /chall/ping-service.py # ubah nama file
 RUN chmod 775 /chall/ping-service.py # ubah nama file