johnoliver · Copilot · Jun 17, 2026 · Jun 17, 2026 · Jun 17, 2026 · Jun 17, 2026
diff --git a/.github/workflows/e2e-versions.yml b/.github/workflows/e2e-versions.yml
@@ -292,6 +292,29 @@ jobs:
         run: bash __tests__/verify-java.sh "${{ matrix.version }}" "${{ steps.setup-java.outputs.path }}"
         shell: bash
 
+  setup-java-temurin-signature-verification:
+    name: temurin ${{ matrix.version }} signature verification - ${{ matrix.os }}
+    needs: setup-java-major-minor-versions
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        os: [macos-latest, windows-latest, ubuntu-latest]
+        version: ['21', '17']
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v6
+      - name: setup-java with signature verification
+        uses: ./
+        id: setup-java
+        with:
+          java-version: ${{ matrix.version }}
+          distribution: temurin
+          verify-signature: true
+      - name: Verify Java
+        run: bash __tests__/verify-java.sh "${{ matrix.version }}" "${{ steps.setup-java.outputs.path }}"
+        shell: bash
+
   setup-java-ea-versions-sapmachine:
     name: sapmachine ${{ matrix.version }} (jdk-x64) - ${{ matrix.os }}
     needs: setup-java-major-minor-versions

diff --git a/README.md b/README.md
@@ -48,6 +48,8 @@ For information about the latest releases, recent updates, and newly supported d
 
   - `check-latest`: Setting this option makes the action to check for the latest available version for the version spec.
 
+  - `verify-signature`: Verifies downloaded Java package signatures when supported by the selected distribution. Currently supported for `temurin`. If set to `true` for unsupported distributions, the action fails.
+
   - `cache`: Quick [setup caching](#caching-packages-dependencies) for the dependencies managed through one of the predefined package managers. It can be one of "maven", "gradle" or "sbt".
 
   - `cache-dependency-path`: The path to a dependency file: pom.xml, build.gradle, build.sbt, etc. This option can be used with the `cache` option. If this option is omitted, the action searches for the dependency file in the entire repository. This option supports wildcards and a list of file names for caching multiple dependencies.

diff --git a/__tests__/data/temurin.json b/__tests__/data/temurin.json
diff --git a/__tests__/distributors/base-installer.test.ts b/__tests__/distributors/base-installer.test.ts
@@ -464,6 +464,24 @@ describe('setupJava', () => {
     }
   );
 
+  it('should fail when verify-signature is enabled for unsupported distributions', async () => {
+    mockJavaBase = new EmptyJavaBase({
+      version: '11',
+      architecture: 'x86',
+      packageType: 'jdk',
+      checkLatest: false,
+      verifySignature: true
+    });
+
+    await expect(mockJavaBase.setupJava()).rejects.toThrow(
+      "Input 'verify-signature' is not supported for distribution 'Empty'."
+    );
+    expect(spyTcFindAllVersions).not.toHaveBeenCalled();
+    expect(spyCoreAddPath).not.toHaveBeenCalled();
+    expect(spyCoreExportVariable).not.toHaveBeenCalled();
+    expect(spyCoreSetOutput).not.toHaveBeenCalled();
+  });
+
   it.each([
     [
       {

diff --git a/__tests__/distributors/temurin-installer.test.ts b/__tests__/distributors/temurin-installer.test.ts
@@ -1,10 +1,15 @@
 import {HttpClient} from '@actions/http-client';
+import * as tc from '@actions/tool-cache';
+import fs from 'fs';
 import os from 'os';
 import {
   TemurinDistribution,
-  TemurinImplementation
+  TemurinImplementation,
+  ADOPTIUM_SIGNATURE_KEY_FINGERPRINT
 } from '../../src/distributions/temurin/installer';
 import {JavaInstallerOptions} from '../../src/distributions/base-models';
+import * as util from '../../src/util';
+import * as gpg from '../../src/gpg';
 
 import manifestData from '../data/temurin.json';
 import * as core from '@actions/core';
@@ -231,6 +236,7 @@ describe('findPackageForDownload', () => {
     distribution['getAvailableVersions'] = async () => manifestData as any;
     const resolvedVersion = await distribution['findPackageForDownload'](input);
     expect(resolvedVersion.version).toBe(expected);
+    expect(resolvedVersion.signatureUrl).toBeDefined();
   });
 
   it('version is found but binaries list is empty', async () => {
@@ -281,3 +287,81 @@ describe('findPackageForDownload', () => {
     );
   });
 });
+
+describe('downloadTool', () => {
+  let spyDownloadTool: jest.SpyInstance;
+  let spyVerifySignature: jest.SpyInstance;
+  let spyExtractJdkFile: jest.SpyInstance;
+  let spyCacheDir: jest.SpyInstance;
+  let spyReadDirSync: jest.SpyInstance;
+  let spyRenameWinArchive: jest.SpyInstance;
+
+  beforeEach(() => {
+    spyDownloadTool = jest.spyOn(tc, 'downloadTool');
+    spyDownloadTool.mockResolvedValue('/tmp/jdk.tar.gz');
+    spyVerifySignature = jest.spyOn(gpg, 'verifyPackageSignature');
+    spyVerifySignature.mockResolvedValue(undefined);
+    spyExtractJdkFile = jest.spyOn(util, 'extractJdkFile');
+    spyExtractJdkFile.mockResolvedValue('/tmp/extracted');
+    spyCacheDir = jest.spyOn(tc, 'cacheDir');
+    spyCacheDir.mockResolvedValue('/tmp/toolcache');
+    spyReadDirSync = jest.spyOn(fs, 'readdirSync');
+    spyReadDirSync.mockReturnValue(['jdk-17'] as any);
+    spyRenameWinArchive = jest.spyOn(util, 'renameWinArchive');
+    spyRenameWinArchive.mockReturnValue('/tmp/jdk.tar.gz.zip');
+  });
+
+  afterEach(() => {
+    jest.resetAllMocks();
+    jest.clearAllMocks();
+    jest.restoreAllMocks();
+  });
+
+  it('verifies signature when enabled', async () => {
+    const distribution = new TemurinDistribution(
+      {
+        version: '17',
+        architecture: 'x64',
+        packageType: 'jdk',
+        checkLatest: false,
+        verifySignature: true
+      },
+      TemurinImplementation.Hotspot
+    );
+
+    await distribution['downloadTool']({
+      version: '17.0.14+7',
+      url: 'https://example.com/jdk.tar.gz',
+      signatureUrl: 'https://example.com/jdk.tar.gz.sig'
+    });
+
+    expect(spyVerifySignature).toHaveBeenCalledWith(
+      '/tmp/jdk.tar.gz',
+      'https://example.com/jdk.tar.gz.sig',
+      ADOPTIUM_SIGNATURE_KEY_FINGERPRINT
+    );
+  });
+
+  it('fails when signature is missing and verification is enabled', async () => {
+    const distribution = new TemurinDistribution(
+      {
+        version: '17',
+        architecture: 'x64',
+        packageType: 'jdk',
+        checkLatest: false,
+        verifySignature: true
+      },
+      TemurinImplementation.Hotspot
+    );
+
+    await expect(
+      distribution['downloadTool']({
+        version: '17.0.14+7',
+        url: 'https://example.com/jdk.tar.gz'
+      })
+    ).rejects.toThrow(
+      "Input 'verify-signature' is enabled, but no signature URL was found"
+    );
+    expect(spyVerifySignature).not.toHaveBeenCalled();
+  });
+});
diff --git a/__tests__/gpg.test.ts b/__tests__/gpg.test.ts
@@ -1,6 +1,7 @@
 import * as path from 'path';
 import * as io from '@actions/io';
 import * as exec from '@actions/exec';
+import * as tc from '@actions/tool-cache';
 import * as gpg from '../src/gpg';
 
 jest.mock('@actions/exec', () => {
@@ -9,6 +10,12 @@ jest.mock('@actions/exec', () => {
   };
 });
 
+jest.mock('@actions/tool-cache', () => {
+  return {
+    downloadTool: jest.fn()
+  };
+});
+
 const tempDir = path.join(__dirname, 'runner', 'temp');
 process.env['RUNNER_TEMP'] = tempDir;
 
@@ -51,5 +58,39 @@ describe('gpg tests', () => {
         expect.anything()
       );
     });
+
+    describe('verifyPackageSignature', () => {
+      it('downloads signature and verifies package', async () => {
+        const testFingerprint = '3B04D753C9050D9A5D343F39843C48A565F8F04B';
+        (tc.downloadTool as jest.Mock).mockResolvedValue('/tmp/jdk.tar.gz.sig');
+        await gpg.verifyPackageSignature(
+          '/tmp/jdk.tar.gz',
+          'https://example.com/jdk.tar.gz.sig',
+          testFingerprint
+        );
+
+        expect(tc.downloadTool).toHaveBeenCalledWith(
+          'https://example.com/jdk.tar.gz.sig'
+        );
+        expect(exec.exec).toHaveBeenNthCalledWith(
+          1,
+          'gpg',
+          [
+            '--batch',
+            '--keyserver',
+            'keyserver.ubuntu.com',
+            '--recv-keys',
+            testFingerprint
+          ],
+          expect.objectContaining({silent: true})
+        );
+        expect(exec.exec).toHaveBeenNthCalledWith(
+          2,
+          'gpg',
+          ['--batch', '--verify', '/tmp/jdk.tar.gz.sig', '/tmp/jdk.tar.gz'],
+          expect.objectContaining({silent: true})
+        );
+      });
+    });
   });
 });
diff --git a/action.yml b/action.yml
@@ -24,6 +24,10 @@ inputs:
     description: 'Set this option if you want the action to check for the latest available version that satisfies the version spec'
     required: false
     default: false
+  verify-signature:
+    description: 'Verify downloaded Java package signatures when supported by the selected distribution'
+    required: false
+    default: false
   server-id:
     description: 'ID of the distributionManagement repository in the pom.xml
        file. Default is `github`'

diff --git a/dist/cleanup/index.js b/dist/cleanup/index.js
@@ -51996,7 +51996,7 @@ else {
 "use strict";
 
 Object.defineProperty(exports, "__esModule", ({ value: true }));
-exports.DISTRIBUTIONS_ONLY_MAJOR_VERSION = exports.INPUT_MVN_TOOLCHAIN_VENDOR = exports.INPUT_MVN_TOOLCHAIN_ID = exports.MVN_TOOLCHAINS_FILE = exports.MVN_SETTINGS_FILE = exports.M2_DIR = exports.STATE_GPG_PRIVATE_KEY_FINGERPRINT = exports.INPUT_JOB_STATUS = exports.INPUT_CACHE_DEPENDENCY_PATH = exports.INPUT_CACHE = exports.INPUT_DEFAULT_GPG_PASSPHRASE = exports.INPUT_DEFAULT_GPG_PRIVATE_KEY = exports.INPUT_GPG_PASSPHRASE = exports.INPUT_GPG_PRIVATE_KEY = exports.INPUT_OVERWRITE_SETTINGS = exports.INPUT_SETTINGS_PATH = exports.INPUT_SERVER_PASSWORD = exports.INPUT_SERVER_USERNAME = exports.INPUT_SERVER_ID = exports.INPUT_CHECK_LATEST = exports.INPUT_JDK_FILE = exports.INPUT_DISTRIBUTION = exports.INPUT_JAVA_PACKAGE = exports.INPUT_ARCHITECTURE = exports.INPUT_JAVA_VERSION_FILE = exports.INPUT_JAVA_VERSION = exports.MACOS_JAVA_CONTENT_POSTFIX = void 0;
+exports.DISTRIBUTIONS_ONLY_MAJOR_VERSION = exports.INPUT_MVN_TOOLCHAIN_VENDOR = exports.INPUT_MVN_TOOLCHAIN_ID = exports.MVN_TOOLCHAINS_FILE = exports.MVN_SETTINGS_FILE = exports.M2_DIR = exports.STATE_GPG_PRIVATE_KEY_FINGERPRINT = exports.INPUT_JOB_STATUS = exports.INPUT_CACHE_DEPENDENCY_PATH = exports.INPUT_CACHE = exports.INPUT_DEFAULT_GPG_PASSPHRASE = exports.INPUT_DEFAULT_GPG_PRIVATE_KEY = exports.INPUT_GPG_PASSPHRASE = exports.INPUT_GPG_PRIVATE_KEY = exports.INPUT_OVERWRITE_SETTINGS = exports.INPUT_SETTINGS_PATH = exports.INPUT_SERVER_PASSWORD = exports.INPUT_SERVER_USERNAME = exports.INPUT_SERVER_ID = exports.INPUT_VERIFY_SIGNATURE = exports.INPUT_CHECK_LATEST = exports.INPUT_JDK_FILE = exports.INPUT_DISTRIBUTION = exports.INPUT_JAVA_PACKAGE = exports.INPUT_ARCHITECTURE = exports.INPUT_JAVA_VERSION_FILE = exports.INPUT_JAVA_VERSION = exports.MACOS_JAVA_CONTENT_POSTFIX = void 0;
 exports.MACOS_JAVA_CONTENT_POSTFIX = 'Contents/Home';
 exports.INPUT_JAVA_VERSION = 'java-version';
 exports.INPUT_JAVA_VERSION_FILE = 'java-version-file';
@@ -52005,6 +52005,7 @@ exports.INPUT_JAVA_PACKAGE = 'java-package';
 exports.INPUT_DISTRIBUTION = 'distribution';
 exports.INPUT_JDK_FILE = 'jdkFile';
 exports.INPUT_CHECK_LATEST = 'check-latest';
+exports.INPUT_VERIFY_SIGNATURE = 'verify-signature';
 exports.INPUT_SERVER_ID = 'server-id';
 exports.INPUT_SERVER_USERNAME = 'server-username';
 exports.INPUT_SERVER_PASSWORD = 'server-password';
@@ -52066,11 +52067,12 @@ var __awaiter = (this && this.__awaiter) || function (thisArg, _arguments, P, ge
     });
 };
 Object.defineProperty(exports, "__esModule", ({ value: true }));
-exports.deleteKey = exports.importKey = exports.PRIVATE_KEY_FILE = void 0;
+exports.verifyPackageSignature = exports.deleteKey = exports.importKey = exports.PRIVATE_KEY_FILE = void 0;
 const fs = __importStar(__nccwpck_require__(79896));
 const path = __importStar(__nccwpck_require__(16928));
 const io = __importStar(__nccwpck_require__(94994));
 const exec = __importStar(__nccwpck_require__(95236));
+const tc = __importStar(__nccwpck_require__(33472));
 const util = __importStar(__nccwpck_require__(54527));
 exports.PRIVATE_KEY_FILE = path.join(util.getTempDir(), 'private-key.asc');
 const PRIVATE_KEY_FINGERPRINT_REGEX = /\w{40}/;
@@ -52110,6 +52112,35 @@ function deleteKey(keyFingerprint) {
     });
 }
 exports.deleteKey = deleteKey;
+function verifyPackageSignature(archivePath, signatureUrl, keyFingerprint) {
+    return __awaiter(this, void 0, void 0, function* () {
+        const signaturePath = yield tc.downloadTool(signatureUrl);
+        let gpgHome;
+        try {
+            gpgHome = fs.mkdtempSync(path.join(util.getTempDir(), 'verify-signature-gpg-home-'));
+        }
+        catch (error) {
+            throw new Error(`Failed to create temporary GPG home directory for signature verification: ${error.message}`);
+        }
+        const env = Object.assign(Object.assign({}, process.env), { GNUPGHOME: gpgHome });
+        try {
+            const options = { silent: true, env };
+            yield exec.exec('gpg', [
+                '--batch',
+                '--keyserver',
+                'keyserver.ubuntu.com',
+                '--recv-keys',
+                keyFingerprint
+            ], options);
+            yield exec.exec('gpg', ['--batch', '--verify', signaturePath, archivePath], options);
+        }
+        finally {
+            yield io.rmRF(signaturePath);
+            yield io.rmRF(gpgHome);
+        }
+    });
+}
+exports.verifyPackageSignature = verifyPackageSignature;
 
 
 /***/ }),