Improve global proxy tests

pr-checks/checks/global-proxy.yml

@@ -5,17 +5,45 @@ versions:
   - nightly-latest
 container:
   image: ubuntu:22.04
+  options: --cap-add=NET_ADMIN
 services:
   squid-proxy:
     image: ubuntu/squid:latest
     ports:
       - 3128:3128
 env:
-  https_proxy: http://squid-proxy:3128
   CODEQL_ACTION_TOLERATE_MISSING_GIT_VERSION: true
 steps:
+  - name: Block direct internet access to force proxy usage
+    run: |
+      apt-get update -qq && apt-get install -y -qq iptables >/dev/null 2>&1
+      PROXY_IP=$(getent hosts squid-proxy | awk '{ print $1 }')
+      echo "Squid proxy IP: $PROXY_IP"
+      # Allow all traffic to the proxy container
+      iptables -A OUTPUT -d "$PROXY_IP" -j ACCEPT
+      # Allow DNS resolution
+      iptables -A OUTPUT -p udp --dport 53 -j ACCEPT
+      iptables -A OUTPUT -p tcp --dport 53 -j ACCEPT
+      # Allow loopback
+      iptables -A OUTPUT -o lo -j ACCEPT
+      # Allow already-established connections (from checkout/prepare-test)
+      iptables -A OUTPUT -m conntrack --ctstate ESTABLISHED,RELATED -j ACCEPT
+      # Block all other outbound HTTP and HTTPS, ensuring direct access fails
+      iptables -A OUTPUT -p tcp --dport 80 -j REJECT --reject-with tcp-reset
+      iptables -A OUTPUT -p tcp --dport 443 -j REJECT --reject-with tcp-reset
+      echo "Direct HTTP/HTTPS access is now blocked - all traffic must go through the proxy"
+
+  - name: Set proxy environment variables
+    shell: bash
+    run: |
+      echo "http_proxy=http://squid-proxy:3128" >> $GITHUB_ENV
+      echo "HTTP_PROXY=http://squid-proxy:3128" >> $GITHUB_ENV
+      echo "https_proxy=http://squid-proxy:3128" >> $GITHUB_ENV
+      echo "HTTPS_PROXY=http://squid-proxy:3128" >> $GITHUB_ENV
+
   - uses: ./../action/init
     with:
       languages: javascript
       tools: ${{ steps.prepare-test.outputs.tools-url }}
+
   - uses: ./../action/analyze

src/api-client.test.ts

@@ -2,6 +2,7 @@ import * as github from "@actions/github";
 import * as githubUtils from "@actions/github/lib/utils";
 import test from "ava";
 import * as sinon from "sinon";
+import { ProxyAgent } from "undici";
 
 import * as actionsUtil from "./actions-util";
 import * as api from "./api-client";
@@ -251,3 +252,23 @@ test("getRegistryProxyConfig - gets the configuration from the env vars", async
     )
     .passes(t.like, { host, port, ca });
 });
+
+test("makeProxyRequestOptions - returns defaults without custom proxy", async (t) => {
+  t.deepEqual(
+    api.makeProxyRequestOptions(undefined),
+    githubUtils.defaults.request,
+  );
+});
+
+test("makeProxyRequestOptions - returns fetch with custom proxy", async (t) => {
+  const opts = api.makeProxyRequestOptions(
+    new ProxyAgent("http://localhost:1080"),
+  );
+  // Fetch should be different from the defaults.
+  t.notDeepEqual(opts?.fetch, githubUtils.defaults.request?.fetch);
+  // The options should be the same aside from that.
+  t.deepEqual(
+    { ...opts, fetch: githubUtils.defaults.request?.fetch },
+    githubUtils.defaults.request,
+  );
+});

src/api-client.ts

@@ -108,12 +108,19 @@ export function getRegistryProxy(
  * Constructs a `RequestRequestOptions` with a custom `fetch` implementation
  * that uses `dispatcher` as a proxy for requests.
  *
- * @param dispatcher The proxy to use.
+ * @param dispatcher The proxy to use, if any.
  */
 export function makeProxyRequestOptions(
-  dispatcher: ProxyAgent,
-): RequestRequestOptions {
+  dispatcher: ProxyAgent | undefined,
+): RequestRequestOptions | undefined {
+  // If we don't have a custom `ProxyAgent`, return the defaults.
+  if (dispatcher === undefined) {
+    return githubUtils.defaults.request;
+  }
+
+  // Otherwise, construct the custom `fetch` and add it onto the defaults.
   return {
+    ...githubUtils.defaults.request,
     fetch: (req: RequestInfo, init?: RequestInit) => {
       return undiciFetch(req, { ...init, dispatcher });
     },
@@ -136,10 +143,7 @@ function createApiClientWithDetails(
   const auth =
     (allowExternal && apiDetails.externalRepoAuth) || apiDetails.auth;
   const retryingOctokit = githubUtils.GitHub.plugin(retry.retry);
-  const requestOptions =
-    proxy === undefined
-      ? githubUtils.defaults.request
-      : makeProxyRequestOptions(proxy);
+  const requestOptions = makeProxyRequestOptions(proxy);
   return new retryingOctokit(
     githubUtils.getOctokitOptions(auth, {
       baseUrl: apiDetails.apiURL,