1 files changed, 25 insertions, 0 deletions
diff --git a/chall/Dockerfile b/chall/Dockerfile
new file mode 100644
index 0000000..9606414
--- /dev/null
+++ b/chall/Dockerfile
@@ -0,0 +1,25 @@
+FROM ubuntu:jammy
+
+RUN apt-get update && apt-get -y install openssh-server file procps
+
+WORKDIR /app
+
+RUN groupadd -r ctf && useradd -m -r -g ctf ctf
+RUN echo "ctf:ctf" | chpasswd
+
+RUN echo 'ForceCommand "/app/checker.sh"' >> /etc/ssh/sshd_config
+RUN echo 'Port 2022' >> /etc/ssh/sshd_config
+RUN mkdir /var/run/sshd
+
+COPY flag.txt /
+COPY checker.sh /app/
+
+RUN chmod 444 /flag.txt
+RUN chmod 555 /app/checker.sh
+
+CMD while true; do \
+        # kill long running processes for ssh
+        ps -eo comm,pid,etimes | awk '/^checker.sh/ {if ($3 > 10) { print $2 }}' | xargs --no-run-if-empty kill -9; \
+        sleep 5s; \
+    done & \
+    /sbin/sshd -D