cscg ist super

2026/cscg/misc/table-madness/service-entry/Dockerfile

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+FROM debian:bookworm AS builder
+
+RUN \
+    --mount=type=cache,target=/var/cache/apt,sharing=locked \
+    --mount=type=cache,target=/var/lib/apt,sharing=locked \
+    apt-get update && apt-get install -y --no-install-recommends \
+    libguestfs-tools cloud-image-utils curl linux-image-amd64 \
+    && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /build
+
+RUN chmod 0644 /boot/vmlinuz*
+
+RUN curl -Lo user.qcow2 https://cloud.debian.org/images/cloud/bookworm/20260316-2418/debian-12-nocloud-amd64-20260316-2418.qcow2 && \
+    echo "661a11d853616ba72913ace404961a28350c58eb4041edd2c847aec932d5b99b user.qcow2" | sha256sum --check
+
+COPY entry.service vmentry.sh .
+
+RUN virt-customize -a user.qcow2 \
+    --update \
+    --install socat \
+    --install python3 \
+    --upload vmentry.sh:/vmentry.sh \
+    --upload entry.service:/etc/systemd/system/entry.service \
+    --run-command 'systemctl daemon-reload && systemctl enable entry.service' \
+    --run-command 'chmod +x /vmentry.sh' \
+    --run-command 'rm -rf /var/lib/apt/lists/*'
+
+FROM debian:bookworm-slim
+
+RUN  \
+    --mount=type=cache,target=/var/cache/apt,sharing=locked \
+    --mount=type=cache,target=/var/lib/apt,sharing=locked \
+    apt-get update && apt-get install -y --no-install-recommends \
+    qemu-system-x86 qemu-utils qemu-kvm \
+    && rm -rf /var/lib/apt/lists/*
+
+COPY --from=builder /build/user.qcow2 /vm/
+
+COPY entrypoint.sh /entrypoint.sh
+
+RUN chmod +x /entrypoint.sh
+CMD ["/entrypoint.sh"]

2026/cscg/misc/table-madness/service-entry/entry.service

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+[Unit]
+Description=Challenge
+After=network.target
+Wants=network.target
+
+[Service]
+Type=simple
+ExecStart=/bin/bash /vmentry.sh
+Restart=on-failure
+RestartSec=5s
+
+[Install]
+WantedBy=multi-user.target

2026/cscg/misc/table-madness/service-entry/entrypoint.sh

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+#!/bin/bash
+qemu-system-x86_64 \
+    -drive file=/vm/user.qcow2,format=qcow2 \
+    -m 512M \
+    -smp 2 \
+    -enable-kvm \
+    -nographic \
+    -display none \
+    -monitor none \
+    -snapshot \
+    -serial null \
+    -device virtio-net-pci,netdev=net0 \
+    -netdev user,id=net0,hostfwd=tcp::1024-:1024 \
+    -netdev socket,id=net1,connect=service-target:5555 \
+    -device e1000,netdev=net1,mac=52:54:00:AA:BB:CC \

2026/cscg/misc/table-madness/service-entry/vmentry.sh

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+#!/bin/bash
+IFACE=$(ip -o link | grep -i 52:54:00:AA:BB:CC | cut -d':' -f2 | xargs)
+ip addr add 192.168.100.1/24 dev "$IFACE"
+ip link set "$IFACE" up
+socat TCP-LISTEN:1024,reuseaddr,fork EXEC:"/bin/bash -li",pty,stderr,setsid,sane