Fix from review

dist/index.js

@@ -14,6 +14,7 @@ import * as fs$2 from 'node:fs/promises';
 import * as os$1 from 'node:os';
 import * as path$1 from 'node:path';
 import { join } from 'node:path';
+import { randomBytes } from 'node:crypto';
 import * as fs$1 from 'node:fs';
 import fs__default from 'node:fs';
 import 'http';
@@ -3900,6 +3901,10 @@ function toSemVer(version) {
 const SONARSOURCE_KEY_FINGERPRINT = "679F1EE92B19609DE816FDE81DB198F93525EC1A";
 const DEFAULT_KEYSERVER = "hkps://keyserver.ubuntu.com";
 const FALLBACK_KEYSERVER = "hkps://keys.openpgp.org";
+// Linux/macOS sockaddr_un.sun_path limit is 108 bytes including the NUL terminator.
+// S.gpg-agent.browser is the longest socket GPG creates directly under the home directory.
+const MAX_GPG_SOCKET_PATH = 107;
+const LONGEST_GPG_SOCKET = "/S.gpg-agent.browser";
 
 /**
  * Verifies the GPG signature of a downloaded file
@@ -3990,12 +3995,22 @@ function convertToUnixPath(windowsPath) {
  * @returns {string} Path to the temporary GPG home directory
  */
 function setupGpgHome() {
-  const tempDir = process.env.RUNNER_TEMP || os$1.tmpdir();
-  const gpgHome = path$1.join(tempDir, `gpg-home-${Date.now()}-${process.pid}`);
+  const dirName = `gpg-${randomBytes(4).toString("hex")}`;
 
-  fs$1.mkdirSync(gpgHome, { recursive: true, mode: 0o700 });
+  const runnertemp = process.env.RUNNER_TEMP;
+  for (const base of [runnertemp, os$1.tmpdir()].filter(Boolean)) {
+    const gpgHome = path$1.join(base, dirName);
+    if (process.platform === "win32" || (gpgHome + LONGEST_GPG_SOCKET).length <= MAX_GPG_SOCKET_PATH) {
+      fs$1.mkdirSync(gpgHome, { recursive: true, mode: 0o700 });
+      return gpgHome;
+    }
+  }
 
-  return gpgHome;
+  throw new Error(
+    `Cannot create a GPG home directory with a short enough path for GPG sockets. ` +
+    `The longest socket path (gpgHome + "${LONGEST_GPG_SOCKET}") must not exceed ${MAX_GPG_SOCKET_PATH} characters. ` +
+    `Consider setting RUNNER_TEMP to a shorter path, was "${runnertemp || '<empty>'}".`
+  );
 }
 
 /**

src/main/__tests__/gpg-verification-mocked.test.js

@@ -20,7 +20,9 @@
 
 import assert from "node:assert/strict";
 import * as fs from "node:fs";
-import { afterEach, describe, it, mock } from "node:test";
+import * as os from "node:os";
+import * as path from "node:path";
+import { afterEach, beforeEach, describe, it, mock } from "node:test";
 import { getProxyFromEnv, setupGpgHome, } from "../gpg-verification.js";
 
 /**
@@ -492,6 +494,76 @@ describe("gpg-verification with mocked exec", () => {
     });
   });
 
+  describe("setupGpgHome", () => {
+    let originalRunnerTemp;
+
+    beforeEach(() => {
+      originalRunnerTemp = process.env.RUNNER_TEMP;
+    });
+
+    afterEach(() => {
+      if (originalRunnerTemp === undefined) {
+        delete process.env.RUNNER_TEMP;
+      } else {
+        process.env.RUNNER_TEMP = originalRunnerTemp;
+      }
+    });
+
+    it("should create directory under RUNNER_TEMP when path is short enough", () => {
+      const runnerTemp = fs.mkdtempSync(path.join(os.tmpdir(), "runner-temp-"));
+      tempDirs.push(runnerTemp);
+      process.env.RUNNER_TEMP = runnerTemp;
+
+      const gpgHome = setupGpgHome();
+      tempDirs.push(gpgHome);
+
+      assert.equal(path.dirname(gpgHome), runnerTemp);
+      assert.ok(fs.existsSync(gpgHome));
+    });
+
+    it("should fall back to os.tmpdir() when RUNNER_TEMP is not set", () => {
+      delete process.env.RUNNER_TEMP;
+
+      const gpgHome = setupGpgHome();
+      tempDirs.push(gpgHome);
+
+      assert.equal(path.dirname(gpgHome), os.tmpdir());
+      assert.ok(fs.existsSync(gpgHome));
+    });
+
+    it("should fall back to os.tmpdir() when RUNNER_TEMP path is too long for GPG sockets", () => {
+      // Customer's actual RUNNER_TEMP (93 chars) — pushes the dirmngr socket path over the 107-char Linux limit
+      process.env.RUNNER_TEMP = "/codebuild/output/src2280/src/2bc4e189_61b5_4b91_abc6_9c5c06637b96/actions-runner/_work/_temp";
+
+      const gpgHome = setupGpgHome();
+      tempDirs.push(gpgHome);
+
+      assert.equal(path.dirname(gpgHome), os.tmpdir());
+      assert.ok(fs.existsSync(gpgHome));
+    });
+
+    it("should throw a clear error when all candidate paths are too long", async (t) => {
+      const longPath = "/codebuild/output/src2280/src/2bc4e189_61b5_4b91_abc6_9c5c06637b96/actions-runner/_work/_temp";
+
+      t.mock.module("node:os", {
+        namedExports: {
+          tmpdir: () => longPath,
+        },
+      });
+
+      process.env.RUNNER_TEMP = longPath;
+
+      const { setupGpgHome: freshSetupGpgHome } = await import("../gpg-verification.js?test=both-paths-too-long");
+
+      assert.throws(
+        () => freshSetupGpgHome(),
+        { message: `Cannot create a GPG home directory with a short enough path for GPG sockets. ` +
+                   `The longest socket path (gpgHome + "/S.gpg-agent.browser") must not exceed 107 characters. ` +
+                   `Consider setting RUNNER_TEMP to a shorter path, was "${longPath}".` }
+      );
+    });
+  });
+
   describe("getProxyFromEnv", () => {
     afterEach(() => {
       clearProxyEnv();

src/main/__tests__/gpg-verification.test.js

@@ -101,9 +101,8 @@ async function withMockedEnv(envVars, testFn) {
  * @returns {string} The path to the created temporary directory
  */
 function createTempDir() {
-  const tempDir = path.join(os.tmpdir(), `test-runner-temp-${Date.now()}`);
-  fs.mkdirSync(tempDir, { recursive: true });
-  return tempDir;
+  // Use a short prefix so the gpg socket path stays within the 107-char Linux limit
+  return fs.mkdtempSync(path.join(os.tmpdir(), "r"));
 }
 
 describe("gpg-verification", () => {
@@ -177,10 +176,8 @@ describe("gpg-verification", () => {
       }
     });
 
-    it("should create unique directories on multiple calls", async () => {
+    it("should create unique directories on multiple calls", () => {
       const gpgHome1 = createTrackedGpgHome(tempDirs);
-      // Small delay to ensure different timestamps
-      await new Promise((resolve) => setTimeout(resolve, 10));
       const gpgHome2 = createTrackedGpgHome(tempDirs);
 
       assert.notEqual(gpgHome1, gpgHome2);

src/main/gpg-verification.js

@@ -20,6 +20,7 @@
 
 import * as core from "@actions/core";
 import * as exec from "@actions/exec";
+import { randomBytes } from "node:crypto";
 import * as fs from "node:fs";
 import * as os from "node:os";
 import * as path from "node:path";
@@ -27,6 +28,10 @@ import * as path from "node:path";
 const SONARSOURCE_KEY_FINGERPRINT = "679F1EE92B19609DE816FDE81DB198F93525EC1A";
 const DEFAULT_KEYSERVER = "hkps://keyserver.ubuntu.com";
 const FALLBACK_KEYSERVER = "hkps://keys.openpgp.org";
+// Linux/macOS sockaddr_un.sun_path limit is 108 bytes including the NUL terminator.
+// S.gpg-agent.browser is the longest socket GPG creates directly under the home directory.
+const MAX_GPG_SOCKET_PATH = 107;
+const LONGEST_GPG_SOCKET = "/S.gpg-agent.browser";
 
 /**
  * Verifies the GPG signature of a downloaded file
@@ -117,12 +122,22 @@ export function convertToUnixPath(windowsPath) {
  * @returns {string} Path to the temporary GPG home directory
  */
 export function setupGpgHome() {
-  const tempDir = process.env.RUNNER_TEMP || os.tmpdir();
-  const gpgHome = path.join(tempDir, `gpg-home-${Date.now()}-${process.pid}`);
+  const dirName = `gpg-${randomBytes(4).toString("hex")}`;
 
-  fs.mkdirSync(gpgHome, { recursive: true, mode: 0o700 });
+  const runnertemp = process.env.RUNNER_TEMP;
+  for (const base of [runnertemp, os.tmpdir()].filter(Boolean)) {
+    const gpgHome = path.join(base, dirName);
+    if (process.platform === "win32" || (gpgHome + LONGEST_GPG_SOCKET).length <= MAX_GPG_SOCKET_PATH) {
+      fs.mkdirSync(gpgHome, { recursive: true, mode: 0o700 });
+      return gpgHome;
+    }
+  }
 
-  return gpgHome;
+  throw new Error(
+    `Cannot create a GPG home directory with a short enough path for GPG sockets. ` +
+    `The longest socket path (gpgHome + "${LONGEST_GPG_SOCKET}") must not exceed ${MAX_GPG_SOCKET_PATH} characters. ` +
+    `Consider setting RUNNER_TEMP to a shorter path, was "${runnertemp || '<empty>'}".`
+  );
 }
 
 /**