The packet filter's tools are a bundle the node's runtime serves; its container goes (hq to-be 38 WP4)

nftables drops its container, NET_ADMIN, the container-runtime capability, the runtime base
images and the Dockerfile; its tools are declared as a TypeScript bundle the toolchain compiles
and node-tools loads on every node. The runtime runs as the operator's account, so the tool
runs the filter's commands through sudo without a prompt when it is not root (ADR 0175 §4);
the filter file is the path the manifest's filtering names, no container env carrying it.

modules/nftables/Dockerfile

@@ -1,23 +0,0 @@
-# nftables' runtime: the tool runtime, carrying the packet filter's tools and the binaries they speak.
-#
-# Built from this module's own directory and nothing else (novox/hq ADR 0069). Two bases, named in
-# module.json's `build.on`: the image this is compiled in and the image it runs in.
-ARG BUILD_BASE
-ARG RUNTIME_BASE
-
-FROM ${BUILD_BASE} AS build
-WORKDIR /app/modules/nftables
-COPY . .
-RUN node /app/node_modules/typescript/bin/tsc client.ts tools/index.ts \
-      --module NodeNext --moduleResolution NodeNext --target ES2022 --outDir dist
-
-FROM ${RUNTIME_BASE}
-# The filter's own tools: nft for the machine's ruleset and the mesh's table, iptables for the
-# legacy filter and the tables iptables-nft manages — a predecessor's rules live there (ADR 0168).
-# The container runs on the machine's network with NET_ADMIN (ADR 0170), so these act on the
-# machine's packet filter, not on a namespace of their own.
-RUN apt-get update \
-      && apt-get install -y --no-install-recommends nftables iptables \
-      && rm -rf /var/lib/apt/lists/*
-COPY --from=build /app/modules/nftables/dist /app/modules/nftables/dist
-ENV MESH_TOOL_MODULES=/app/modules/nftables/dist/tools/index.js

modules/nftables/client.ts

@@ -2,7 +2,8 @@
 // rule set from every module's `listens` and writes it to the filter file (ADR 0045); the module
 // loads it through its own unit. This code reads the filter back as the machine enforces it, reloads
 // the mesh's own table, and removes one thing the mesh did not write when the operator names it
-// (ADR 0168, ADR 0170) — the seat's three verbs, over the machine's own tools.
+// (ADR 0168, ADR 0170) — the seat's three verbs, over the machine's own tools, which it runs as root
+// through sudo when the runtime loading it is not (ADR 0175).
 
 import { execFile } from "node:child_process";
 import { promisify } from "node:util";
@@ -12,9 +13,27 @@ const execFileP = promisify(execFile);
 /** A command runner, so the acts can be tested without a packet filter. */
 export type Runner = (cmd: string, args: string[]) => Promise<string>;
 
+/** The command as it is run: as given when this process is root, else through sudo without a
+ *  prompt. The runtime that loads this bundle runs as the node's operator account, which may
+ *  escalate as the operator would (novox/hq ADR 0175 §4); the packet filter answers only to root,
+ *  listing included. A command sudo refuses fails by name, saying what the account lacks. */
+export function escalated(cmd: string, args: string[], uid: number | undefined = process.getuid?.()): [string, string[]] {
+  if (uid === 0) return [cmd, args];
+  return ["sudo", ["-n", cmd, ...args]];
+}
+
 export const execRunner: Runner = async (cmd, args) => {
-  const { stdout } = await execFileP(cmd, args, { maxBuffer: 16 * 1024 * 1024 });
+  const [program, argv] = escalated(cmd, args);
+  try {
+    const { stdout } = await execFileP(program, argv, { maxBuffer: 16 * 1024 * 1024 });
     return stdout;
+  } catch (err) {
+    const stderr = String((err as { stderr?: string }).stderr ?? "").trim();
+    if (program === "sudo" && /a password is required|not allowed to execute|not in the sudoers/.test(stderr)) {
+      throw new Error(`${cmd} needs root and the runtime's account may not escalate without a prompt: ${stderr}`);
+    }
+    throw err;
+  }
 };
 
 /** The mesh's own tables, which `remove` never touches. */

modules/nftables/module.json

@@ -2,8 +2,7 @@
   "module": "nftables",
   "version": "1",
   "capabilities": [
-    "firewall",
+    "firewall"
-    "container-runtime"
   ],
   "claims": [
     {
@@ -42,7 +41,7 @@
       "id": "stock-unit-stop",
       "type": "file",
       "path": "/etc/systemd/system/nftables.service.d/mesh.conf",
-      "content": "# The mesh: stopping the stock unit deletes only the mesh's table, never the whole ruleset\n# (novox/hq ADR 0100) \u2014 a flush would take the container runtime's rules and any firewall with it.\n[Service]\nExecStop=\nExecStop=nft delete table inet mesh\n",
+      "content": "# The mesh: stopping the stock unit deletes only the mesh's table, never the whole ruleset\n# (novox/hq ADR 0100) — a flush would take the container runtime's rules and any firewall with it.\n[Service]\nExecStop=\nExecStop=nft delete table inet mesh\n",
       "mode": "0644"
     },
     {
@@ -64,24 +63,6 @@
       "type": "package",
       "package": "ufw",
       "absent": true
-    },
-    {
-      "id": "runtime",
-      "type": "container",
-      "name": "mesh-nftables",
-      "network": "host",
-      "capabilities": [
-        "NET_ADMIN"
-      ],
-      "volumes": [
-        "${dir:mesh-state}/broker:/run/secrets/broker:ro",
-        "/etc/nftables.conf:/etc/nftables.conf:ro"
-      ],
-      "env": {
-        "MESH_BROKER_FILE": "/run/secrets/broker",
-        "MESH_FILTER_FILE": "/etc/nftables.conf"
-      },
-      "artifact": "runtime"
     }
   ],
   "tools": [
@@ -91,23 +72,14 @@
     "broker": "${dir:mesh-state}/broker"
   },
   "build": {
-    "on": [
-      {
-        "arg": "BUILD_BASE",
-        "module": "mesh-tools",
-        "artifact": "build"
-      },
-      {
-        "arg": "RUNTIME_BASE",
-        "module": "mesh-tools",
-        "artifact": "runtime"
-      }
-    ],
     "artifacts": [
       {
-        "name": "runtime",
+        "name": "tools",
-        "kind": "image",
+        "kind": "bundle",
-        "from": "Dockerfile"
+        "language": "typescript",
+        "entrypoints": [
+          "tools/index.js"
+        ]
       }
     ]
   }

modules/nftables/package.json

@@ -5,7 +5,7 @@
   "type": "module",
   "private": true,
   "scripts": {
-    "build": "tsc client.ts tools/index.ts --module NodeNext --moduleResolution NodeNext --target ES2022 --outDir dist",
+    "build": "tsc client.ts tools/index.ts --module NodeNext --moduleResolution NodeNext --target ES2022 --rootDir . --outDir dist",
     "test": "node --test --experimental-strip-types 'test/*.test.ts'"
   },
   "dependencies": {

modules/nftables/test/remove.test.ts

@@ -4,7 +4,7 @@
 // and the same in an iptables-nft table. It refuses what is not the operator's to remove.
 import { test } from "node:test";
 import assert from "node:assert/strict";
-import { FirewallClient, chainsJumpingTo, type Runner } from "../client.ts";
+import { FirewallClient, chainsJumpingTo, escalated, type Runner } from "../client.ts";
 
 const legacy = [
   "-P INPUT ACCEPT", "-P FORWARD DROP", "-P OUTPUT ACCEPT",
@@ -72,3 +72,9 @@ test("which chains jump to a target is read from a listing", () => {
   const listing = "table ip6 own {\n\tchain a {\n\t\tjump deny\n\t}\n\tchain b {\n\t\tgoto deny\n\t}\n\tchain deny {\n\t\tdrop\n\t}\n}\n";
   assert.deepEqual(chainsJumpingTo(listing, "deny"), ["a", "b"]);
 });
+
+test("the filter's commands run as given by root and through sudo without a prompt by anyone else", () => {
+  assert.deepEqual(escalated("nft", ["list", "ruleset"], 0), ["nft", ["list", "ruleset"]]);
+  assert.deepEqual(escalated("nft", ["-f", "/etc/nftables.conf"], 1000), ["sudo", ["-n", "nft", "-f", "/etc/nftables.conf"]]);
+  assert.deepEqual(escalated("iptables-legacy", ["-S"], undefined), ["sudo", ["-n", "iptables-legacy", "-S"]]);
+});