Merge pull request #2267 from mchaker/mchaker-2022-07-ecs-introspecti…

…on-access

ecs: add `iptables` rules for ECS introspection server

packages/ecs-agent/ecs.service

@@ -13,17 +13,29 @@ RestartSec=1s
 EnvironmentFile=-/etc/ecs/ecs.config
 EnvironmentFile=/etc/network/proxy.env
 Environment=ECS_CHECKPOINT=true
+# Grant ECS tasks access to the ECS task metadata endpoint
 ExecStartPre=/sbin/iptables -t nat -A PREROUTING -d 169.254.170.2/32 \
  -p tcp -m tcp --dport 80 -j DNAT --to-destination 127.0.0.1:51679
 ExecStartPre=/sbin/iptables -t nat -A OUTPUT -d 169.254.170.2/32 \
  -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 51679
+# Grant access to the ECS Introspection server
+ExecStartPre=/sbin/iptables -t nat -A PREROUTING -d 172.17.0.1/32 \
+ -p tcp -m tcp --dport 51678 -j DNAT --to-destination 127.0.0.1:51678
+ExecStartPre=/sbin/iptables -t nat -A OUTPUT -d 172.17.0.1/32 \
+ -p tcp -m tcp --dport 51678 -j REDIRECT --to-ports 51678
 ExecStartPre=/sbin/iptables -t filter -I INPUT --dst 127.0.0.0/8 ! \
  --src 127.0.0.0/8 -m conntrack ! --ctstate RELATED,ESTABLISHED,DNAT -j DROP
 ExecStart=/usr/bin/amazon-ecs-agent
+# Remove access to the ECS task metadata endpoint from ECS tasks
 ExecStopPost=-/sbin/iptables -t nat -D PREROUTING -d 169.254.170.2/32 \
  -p tcp -m tcp --dport 80 -j DNAT --to-destination 127.0.0.1:51679
 ExecStopPost=-/sbin/iptables -t nat -D OUTPUT -d 169.254.170.2/32 \
  -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 51679
+# Remove access to the ECS Introspection server
+ExecStopPost=-/sbin/iptables -t nat -D PREROUTING -d 172.17.0.1/32 \
+ -p tcp -m tcp --dport 51678 -j DNAT --to-destination 127.0.0.1:51678
+ExecStopPost=-/sbin/iptables -t nat -D OUTPUT -d 172.17.0.1/32 \
+ -p tcp -m tcp --dport 51678 -j REDIRECT --to-ports 51678
 ExecStopPost=-/sbin/iptables -t filter -D INPUT --dst 127.0.0.0/8 ! \
  --src 127.0.0.0/8  -m conntrack ! --ctstate RELATED,ESTABLISHED,DNAT -j DROP