1 files changed, 136 insertions, 0 deletions
diff --git a/scripts/network-policy.test.ts b/scripts/network-policy.test.ts
new file mode 100644
index 0000000..4c3ed12
--- /dev/null
+++ b/scripts/network-policy.test.ts
@@ -0,0 +1,136 @@
+import { describe, expect, it } from "vitest";
+import {
+  buildAllowedHosts,
+  checkDevRequest,
+  checkHost,
+  isAllowedLocalAddress,
+  normalizeHost,
+  normalizeHostHeader,
+  tailscaleSelf,
+} from "./network-policy";
+
+// Synthetic status: reserved .example DNS and documentation-only IPv4/IPv6 addresses.
+const tailscaleStatusJson = `{"Self":{"HostName":"laptop",
+  "DNSName":"dev-node.tailnet.example.",
+  "TailscaleIPs":["192.0.2.10","2001:db8::10"]}}`;
+const allowedHosts = buildAllowedHosts({ tailscaleStatusJson, env: {} });
+const allowedAddresses = new Set(["127.0.0.1", "::1", ...tailscaleSelf(tailscaleStatusJson).ips]);
+const policy = { allowedHosts, allowedAddresses };
+const request = (localAddress = "::1", host: string | undefined = "localhost", origin?: string) =>
+  checkDevRequest({ localAddress, host, origin }, policy);
+
+describe("backend-compatible hosts", () => {
+  it.each([
+    ["LOCALHOST.:34204", "localhost"],
+    ["127.0.0.1:34204", "127.0.0.1"],
+    ["[0:0:0:0:0:0:0:1]:34204", "::1"],
+    ["DEV-NODE", "dev-node"],
+    ["DEV-NODE.tailnet.example.:34204", "dev-node.tailnet.example"],
+    ["192.0.2.10:34204", "192.0.2.10"],
+    ["[2001:db8::10]:34204", "2001:db8::10"],
+  ])("normalizes and allows %s", (raw, expected) => {
+    expect(normalizeHost(raw)).toBe(expected);
+    expect(checkHost(raw, allowedHosts)).toBe("ok");
+  });
+
+  it.each(
+    (
+      "evil.com|dev-node.evil.com|192.0.2.10.nip.io|laptop|localhost.evil.com|" +
+      "sub.localhost|127.0.0.2|100.1.2.3|172.17.0.1|[email protected]|localhost/path|" +
+      "localhost:bad|localhost:65536|[::1]suffix|localhost\n|localhost..|%6cocalhost|"
+    ).split("|"),
+  )("rejects %j even where Vite would allow it", (host) => {
+    expect(checkHost(host, allowedHosts)).toMatchObject({ status: 421 });
+  });
+
+  const missingStatuses = [undefined, "invalid", "null", "[]", "{}", '{"Self":null}'];
+  it.each(missingStatuses)("fails closed for status %j, retains env overrides", (json) => {
+    const input = {
+      ...(json !== undefined ? { tailscaleStatusJson: json } : {}),
+      env: {
+        DISPATCH_ALLOWED_HOSTS: " EXTRA.example.:8080, https://evil.com",
+        DISPATCH_TAILSCALE_NAME: "DEV-NODE",
+      },
+    };
+    const expected = "localhost,127.0.0.1,::1,extra.example,dev-node".split(",");
+    expect([...buildAllowedHosts(input)]).toEqual(expected);
+    expect(tailscaleSelf(json)).toEqual({ ips: [] });
+  });
+
+  it("keeps auto-detection when env hosts are supplied, without trusting OS hostname", () => {
+    const hosts = buildAllowedHosts({
+      tailscaleStatusJson,
+      env: { DISPATCH_ALLOWED_HOSTS: "extra.example" },
+    });
+    expect(hosts.has("dev-node.tailnet.example")).toBe(true);
+    expect(hosts.has("extra.example")).toBe(true);
+    expect(hosts.has("laptop")).toBe(false);
+    expect(tailscaleSelf(tailscaleStatusJson).hostName).toBe("laptop");
+    expect(tailscaleSelf('{"Self":{"TailscaleIPs":[null,"evil.com","192.0.2.10"]}}').ips).toEqual([
+      "192.0.2.10",
+    ]);
+  });
+
+  it.each([
+    ["LOCALHOST.:34204", "localhost:34204"],
+    ["[0:0:0:0:0:0:0:1]:34204", "[::1]:34204"],
+    ["[::1]", "[::1]"],
+    ["DEV-NODE.", "dev-node"],
+  ])("preserves valid authorities for Vite: %s", (raw, expected) => {
+    expect(normalizeHostHeader(raw)).toBe(expected);
+  });
+});
+
+describe("destination interfaces (not remote peer addresses)", () => {
+  it.each(
+    (
+      "127.0.0.1|::1|0:0:0:0:0:0:0:1|::ffff:127.0.0.1|::ffff:7f00:1|" +
+      "192.0.2.10|::ffff:192.0.2.10|2001:db8::10"
+    ).split("|"),
+  )("allows local address %s", (address) => {
+    expect(isAllowedLocalAddress(address, allowedAddresses)).toBe(true);
+  });
+
+  it.each([
+    undefined,
+    ..."|172.17.0.1|::ffff:172.17.0.1|192.168.1.2|100.1.2.3|0.0.0.0|::|127.0.0.2".split("|"),
+  ])("rejects non-selected interface %j", (address) => {
+    expect(isAllowedLocalAddress(address, allowedAddresses)).toBe(false);
+    // undefined must not use the helper's default loopback address.
+    expect(
+      checkDevRequest({ localAddress: address, host: "localhost", origin: undefined }, policy),
+    ).toMatchObject({ status: 403 });
+  });
+
+  it("does not treat an env host extra as an allowed interface", () => {
+    const hosts = buildAllowedHosts({ env: { DISPATCH_ALLOWED_HOSTS: "172.17.0.1" } });
+    expect(
+      checkDevRequest(
+        { localAddress: "172.17.0.1", host: "172.17.0.1", origin: undefined },
+        { allowedHosts: hosts, allowedAddresses },
+      ),
+    ).toMatchObject({ status: 403 });
+  });
+});
+
+describe("shared HTTP / HMR request decision", () => {
+  it.each([
+    undefined,
+    "http://DEV-NODE.:34204",
+    "https://[2001:db8::10]:443",
+  ])("allows trusted or absent Origin %j", (origin) => {
+    expect(request("::ffff:192.0.2.10", "dev-node", origin)).toBe("ok");
+  });
+  const badOrigins =
+    "null|file://localhost|https://evil.com|http://localhost/|http://user@localhost";
+  it.each(badOrigins.split("|"))("rejects Origin %j", (origin) => {
+    expect(request("::1", "localhost", origin)).toMatchObject({ status: 403 });
+  });
+  it("requires Host and checks it before Origin", () => {
+    for (const host of [undefined, "evil.com"]) {
+      expect(
+        checkDevRequest({ localAddress: "127.0.0.1", host, origin: "null" }, policy),
+      ).toMatchObject({ status: 421 });
+    }
+  });
+});