Files
clan-core/checks/user-firewall/nftables.nix
Jörg Thalheim 5d88ac440a add restricted network nixos modules
See README.md for explanation
2025-06-27 18:44:17 +02:00

78 lines
3.5 KiB
Nix

{
name = "user-firewall-nftables";
nodes = {
router = {
imports = [ ./router.nix ];
};
machine = {
imports = [ ./common.nix ];
# Force nftables backend
networking.nftables.enable = true;
};
};
testScript = ''
start_all()
router.wait_for_unit("multi-user.target")
router.wait_for_unit("nginx.service")
machine.wait_for_unit("multi-user.target")
machine.wait_for_unit("nginx.service")
# Get router IPs (both IPv4 and IPv6)
router_ip = router.succeed("ip -4 addr show eth1 | grep -oP '(?<=inet\\s)\\d+(\\.\\d+){3}'").strip()
router_ip6 = router.succeed("ip -6 addr show eth1 | grep -oP '(?<=inet6\\s)[0-9a-f:]+' | grep -v '^fe80' | head -1").strip()
print(f"Router IPv4: {router_ip}")
print(f"Router IPv6: {router_ip6}")
# Test nftables restart
machine.succeed("systemctl restart nftables")
machine.wait_for_unit("nftables.service")
# Verify rules are loaded
machine.succeed("nft list table inet user-firewall >&2")
# Test alice (exempt user) - should succeed both locally and to router
machine.wait_until_succeeds("runuser -u alice -- curl -s http://127.0.0.1:8080")
machine.succeed(f"runuser -u alice -- curl -s http://{router_ip}")
machine.succeed(f"runuser -u alice -- curl -s http://[{router_ip6}]")
# Test bob (restricted user) - localhost should work, external should fail
machine.succeed("runuser -u bob -- curl -s http://127.0.0.1:8080")
# This should be blocked by firewall - IPv4
result = machine.succeed(f"runuser -u bob -- curl -s --connect-timeout 2 http://{router_ip} 2>&1 || echo 'EXIT_CODE='$?")
assert "EXIT_CODE=7" in result, f"Bob should be blocked from external IPv4 access (expected EXIT_CODE=7) but got: {result}"
# This should be blocked by firewall - IPv6
result6 = machine.succeed(f"runuser -u bob -- curl -s --connect-timeout 2 http://[{router_ip6}] 2>&1 || echo 'EXIT_CODE='$?")
assert "EXIT_CODE=7" in result6, f"Bob should be blocked from external IPv6 access (expected EXIT_CODE=7) but got: {result6}"
# Verify the rules are actually present
rules = machine.succeed("nft list table inet user-firewall")
assert 'meta skuid 1002' in rules and 'reject' in rules, f"Reject rule for bob (uid 1002) not found in nftables. Actual rules:\n{rules}"
assert "oifname" in rules, f"Interface rules not found in nftables. Actual rules:\n{rules}"
# Wait for the dummy interface to be created
machine.wait_for_unit("setup-wg0-interface.service")
machine.wait_for_unit("nginx.service")
machine.wait_for_open_port(8081, "10.100.0.2")
# Check that wg0 interface exists
machine.succeed("ip link show wg0")
machine.succeed("ip addr show wg0")
# The key test: users should be able to connect via wg0 interface
# For alice (exempt user) - should work
machine.succeed("runuser -u alice -- curl -s --interface wg0 http://10.100.0.2:8081/")
machine.succeed("runuser -u alice -- curl -s --interface wg0 http://[fd00::2]:8081/") # IPv6 test
# For bob (restricted user) - should also work because wg* is in default allowedInterfaces
machine.succeed("runuser -u bob -- curl -s --interface wg0 http://10.100.0.2:8081/")
machine.succeed("runuser -u bob -- curl -s --interface wg0 http://[fd00::2]:8081/") # IPv6 test
# Verify that wg* interfaces are allowed in the nftables rules
rules_with_wg = machine.succeed("nft list table inet user-firewall | grep -E 'oifname.*wg' >&2")
'';
}