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fix: egress filtering when running as non-root user #118

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fix: egress filtering when running as non-root user #118

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8 changes: 5 additions & 3 deletions entrypoint.sh
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Original file line number Diff line number Diff line change
Expand Up @@ -152,14 +152,16 @@ if [ "${OPEN_TERMINAL_ALLOWED_DOMAINS+set}" = "set" ]; then
echo "nameserver 127.0.0.1" | sudo tee /etc/resolv.conf > /dev/null

# iptables: allow ONLY resolved IPs (via ipset) + block everything else
sudo iptables -A OUTPUT -p udp --dport 53 -j DROP # block external DNS
sudo iptables -A OUTPUT -p tcp --dport 53 -j DROP # block external DNS
sudo iptables -A OUTPUT -p udp -d "$UPSTREAM_DNS" --dport 53 -j ACCEPT # allow dnsmasq → upstream DNS
sudo iptables -A OUTPUT -p tcp -d "$UPSTREAM_DNS" --dport 53 -j ACCEPT # allow dnsmasq → upstream DNS (TCP)
sudo iptables -A OUTPUT -p udp --dport 53 -j DROP # block all other external DNS
sudo iptables -A OUTPUT -p tcp --dport 53 -j DROP # block all other external DNS
sudo iptables -A OUTPUT -m set --match-set allowed dst -j ACCEPT # allow resolved IPs
sudo iptables -A OUTPUT -j DROP # drop everything else
fi

echo "Egress firewall active — dropping CAP_NET_ADMIN permanently"
exec capsh --drop=cap_net_admin -- -c "exec open-terminal $*"
exec sudo capsh --drop=cap_net_admin --user=user -- -c "exec open-terminal $*"
fi

exec open-terminal "$@"