add ubuntu support

ChallengeDockerfile

@@ -0,0 +1,10 @@
+# The basic dockerfile that is loaded for each console.
+# should take ~1MB per open console.
+FROM ubuntu:22.04 
+
+COPY SETUP.sh SETUP.sh
+RUN bash SETUP.sh
+RUN rm SETUP.sh
+
+CMD ["/bin/bash"]
+

Dockerfile

@@ -12,6 +12,8 @@ COPY --from=download-gotty /go/bin/gotty /app/gotty
 RUN mkdir /lib64 && ln -s /lib/libc.musl-x86_64.so.1 /lib64/ld-linux-x86-64.so.2
 
 COPY start-shell.sh start-shell.sh
+COPY ChallengeDockerfile Dockerfile
+COPY SETUP.sh SETUP.sh
 
 # run docker containers inside this docker container.
 # therefore, each client is isolated from each other

SETUP.sh

@@ -0,0 +1,18 @@
+#!/bin/bash
+
+apt update && apt upgrade -y && apt install tmux htop vim -y # install generally helpful packages
+cat << EOF > /etc/motd
+Hi! You're currently running Ubuntu Linux version 22.04.
+Run 'help' for help. 
+We recommend using the mouse to select, copy, and paste text.
+This terminal will close after 5 minutes to save resources.
+EOF
+printf "\ncat /etc/motd\n# hello!\n" >> /root/.bashrc
+
+cat << "EOF" >> /root/.bashrc
+# custom prompt
+PS1='${debian_chroot:+($debian_chroot)}\[\033[01;32m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ '
+
+cd "$HOME"
+EOF
+

start-shell.sh

@@ -1,11 +1,21 @@
 #!/bin/sh
 
+set -e
+
+# This script is loaded by gotty, and is in charge of starting a jailed and virtualized console.
+# This script is loaded by "Dockerfile"
+# This script depends on "ChallengeDockerfile"
+
 CONTAINER_NAME="challenge-shell-$RANDOM"
+CONTAINER_TAG="webshell"
+TIMEOUT="300" # 300 seconds = 5 minutes
 
-TIMEOUT="600" # 600 seconds = 10 minutes
+# Build image from ChallengeDockerfile
+docker build --tag "$CONTAINER_TAG" .
 
-(sleep "$TIMEOUT" ; echo "Out of time after $TIMEOUT seconds! Refresh to try again." ; docker stop $CONTAINER_NAME)& 
+clear # clear output
 
-docker run -m 15M --cpu-quota 3000 --name "$CONTAINER_NAME" -it --rm busybox
+(sleep "$TIMEOUT" ; echo "Out of time after $TIMEOUT seconds! Refresh to try again." ; docker stop $CONTAINER_NAME)&
 
+docker run -m 15M --cpu-quota 3000 --name "$CONTAINER_NAME" -it --rm "$CONTAINER_TAG"