fix(security): prevent path traversal in credentials file deletion

Use path.resolve() to normalize paths before comparison in
removeIncludeIfCredentials(). The previous startsWith() check was
vulnerable to path traversal attacks where a path like
"/tmp/runner/../../../etc/passwd" would pass the check but resolve
outside RUNNER_TEMP.

Also append path.sep to prevent false positives (e.g., /tmp/runner2
matching /tmp/runner).

__test__/git-config-helper.int.test.ts

@@ -1,5 +1,7 @@
 import {GitCommandManager} from '../lib/git-command-manager'
 import {GitConfigHelper} from '../lib/git-config-helper'
+import * as fs from 'fs'
+import * as path from 'path'
 
 const REPO_PATH = '/git/local/repos/test-base'
 
@@ -7,29 +9,104 @@ const extraheaderConfigKey = 'http.https://127.0.0.1/.extraheader'
 
 describe('git-config-helper integration tests', () => {
   let git: GitCommandManager
+  let originalRunnerTemp: string | undefined
 
   beforeAll(async () => {
     git = await GitCommandManager.create(REPO_PATH)
   })
 
+  beforeEach(async () => {
+    // Save original RUNNER_TEMP
+    originalRunnerTemp = process.env['RUNNER_TEMP']
+    // Create a temp directory for tests
+    const tempDir = await fs.promises.mkdtemp('/tmp/cpr-test-')
+    process.env['RUNNER_TEMP'] = tempDir
+    process.env['GITHUB_WORKSPACE'] = REPO_PATH
+  })
+
+  afterEach(async () => {
+    // Clean up RUNNER_TEMP
+    const runnerTemp = process.env['RUNNER_TEMP']
+    if (runnerTemp && runnerTemp.startsWith('/tmp/cpr-test-')) {
+      await fs.promises.rm(runnerTemp, {recursive: true, force: true})
+    }
+    // Restore original RUNNER_TEMP
+    if (originalRunnerTemp !== undefined) {
+      process.env['RUNNER_TEMP'] = originalRunnerTemp
+    } else {
+      delete process.env['RUNNER_TEMP']
+    }
+  })
+
   it('tests save and restore with no persisted auth', async () => {
     const gitConfigHelper = await GitConfigHelper.create(git)
     await gitConfigHelper.close()
   })
 
-  it('tests configure and removal of auth', async () => {
+  it('tests configure and removal of auth using credentials file', async () => {
+    const runnerTemp = process.env['RUNNER_TEMP']!
     const gitConfigHelper = await GitConfigHelper.create(git)
     await gitConfigHelper.configureToken('github-token')
-    expect(await git.configExists(extraheaderConfigKey)).toBeTruthy()
-    expect(await git.getConfigValue(extraheaderConfigKey)).toEqual(
+
+    // Verify credentials file was created in RUNNER_TEMP
+    const files = await fs.promises.readdir(runnerTemp)
+    const credentialsFiles = files.filter(
+      f => f.startsWith('git-credentials-') && f.endsWith('.config')
+    )
+    expect(credentialsFiles.length).toBe(1)
+
+    // Verify credentials file contains the auth token
+    const credentialsPath = path.join(runnerTemp, credentialsFiles[0])
+    const credentialsContent = await fs.promises.readFile(
+      credentialsPath,
+      'utf8'
+    )
+    expect(credentialsContent).toContain(
       'AUTHORIZATION: basic eC1hY2Nlc3MtdG9rZW46Z2l0aHViLXRva2Vu'
     )
 
+    // Verify includeIf entries were added to local config
+    const includeIfKeys = await git.tryGetConfigKeys('^includeIf\\.gitdir:')
+    expect(includeIfKeys.length).toBeGreaterThan(0)
+
+    // Count credential includes pointing to this action's credentials file
+    let credentialIncludesForThisAction = 0
+    for (const key of includeIfKeys) {
+      const values = await git.tryGetConfigValues(key)
+      for (const value of values) {
+        if (value === credentialsPath) {
+          credentialIncludesForThisAction++
+        }
+      }
+    }
+    expect(credentialIncludesForThisAction).toBeGreaterThan(0)
+
     await gitConfigHelper.close()
-    expect(await git.configExists(extraheaderConfigKey)).toBeFalsy()
+
+    // Verify credentials file was removed
+    const filesAfter = await fs.promises.readdir(runnerTemp)
+    const credentialsFilesAfter = filesAfter.filter(
+      f => f.startsWith('git-credentials-') && f.endsWith('.config')
+    )
+    expect(credentialsFilesAfter.length).toBe(0)
+
+    // Verify includeIf entries pointing to our specific credentials file were removed
+    const includeIfKeysAfter = await git.tryGetConfigKeys(
+      '^includeIf\\.gitdir:'
+    )
+    let credentialIncludesForThisActionAfter = 0
+    for (const key of includeIfKeysAfter) {
+      const values = await git.tryGetConfigValues(key)
+      for (const value of values) {
+        if (value === credentialsPath) {
+          credentialIncludesForThisActionAfter++
+        }
+      }
+    }
+    expect(credentialIncludesForThisActionAfter).toBe(0)
   })
 
-  it('tests save and restore of persisted auth', async () => {
+  it('tests save and restore of persisted auth (old-style)', async () => {
     const extraheaderConfigValue = 'AUTHORIZATION: basic ***persisted-auth***'
     await git.config(extraheaderConfigKey, extraheaderConfigValue)
 

dist/index.js

@@ -730,9 +730,15 @@ class GitCommandManager {
             return yield this.exec(args, { allowAllExitCodes: allowAllExitCodes });
         });
     }
-    config(configKey, configValue, globalConfig, add) {
+    config(configKey, configValue, globalConfig, add, configFile) {
         return __awaiter(this, void 0, void 0, function* () {
-            const args = ['config', globalConfig ? '--global' : '--local'];
+            const args = ['config'];
+            if (configFile) {
+                args.push('--file', configFile);
+            }
+            else {
+                args.push(globalConfig ? '--global' : '--local');
+            }
             if (add) {
                 args.push('--add');
             }
@@ -964,6 +970,60 @@ class GitCommandManager {
             return output.exitCode === 0;
         });
     }
+    tryConfigUnsetValue(configKey, configValue, globalConfig, configFile) {
+        return __awaiter(this, void 0, void 0, function* () {
+            const args = ['config'];
+            if (configFile) {
+                args.push('--file', configFile);
+            }
+            else {
+                args.push(globalConfig ? '--global' : '--local');
+            }
+            args.push('--fixed-value', '--unset', configKey, configValue);
+            const output = yield this.exec(args, { allowAllExitCodes: true });
+            return output.exitCode === 0;
+        });
+    }
+    tryGetConfigValues(configKey, globalConfig, configFile) {
+        return __awaiter(this, void 0, void 0, function* () {
+            const args = ['config'];
+            if (configFile) {
+                args.push('--file', configFile);
+            }
+            else {
+                args.push(globalConfig ? '--global' : '--local');
+            }
+            args.push('--get-all', configKey);
+            const output = yield this.exec(args, { allowAllExitCodes: true });
+            if (output.exitCode !== 0) {
+                return [];
+            }
+            return output.stdout
+                .trim()
+                .split('\n')
+                .filter(value => value.trim());
+        });
+    }
+    tryGetConfigKeys(pattern, globalConfig, configFile) {
+        return __awaiter(this, void 0, void 0, function* () {
+            const args = ['config'];
+            if (configFile) {
+                args.push('--file', configFile);
+            }
+            else {
+                args.push(globalConfig ? '--global' : '--local');
+            }
+            args.push('--name-only', '--get-regexp', pattern);
+            const output = yield this.exec(args, { allowAllExitCodes: true });
+            if (output.exitCode !== 0) {
+                return [];
+            }
+            return output.stdout
+                .trim()
+                .split('\n')
+                .filter(key => key.trim());
+        });
+    }
     tryGetRemoteUrl() {
         return __awaiter(this, void 0, void 0, function* () {
             const output = yield this.exec(['config', '--local', '--get', 'remote.origin.url'], { allowAllExitCodes: true });
@@ -1100,9 +1160,9 @@ const fs = __importStar(__nccwpck_require__(9896));
 const path = __importStar(__nccwpck_require__(6928));
 const url_1 = __nccwpck_require__(7016);
 const utils = __importStar(__nccwpck_require__(9277));
+const uuid_1 = __nccwpck_require__(2048);
 class GitConfigHelper {
     constructor(git) {
-        this.gitConfigPath = '';
         this.safeDirectoryConfigKey = 'safe.directory';
         this.safeDirectoryAdded = false;
         this.remoteUrl = '';
@@ -1110,7 +1170,8 @@ class GitConfigHelper {
         this.extraheaderConfigPlaceholderValue = 'AUTHORIZATION: basic ***';
         this.extraheaderConfigValueRegex = '^AUTHORIZATION:';
         this.persistedExtraheaderConfigValue = '';
-        this.backedUpCredentialFiles = [];
+        // Path to the credentials config file in RUNNER_TEMP (new v6-style auth)
+        this.credentialsConfigPath = '';
         this.git = git;
         this.workingDirectory = this.git.getWorkingDirectory();
     }
@@ -1190,16 +1251,15 @@ class GitConfigHelper {
         return __awaiter(this, void 0, void 0, function* () {
             const serverUrl = new url_1.URL(`https://${this.getGitRemote().hostname}`);
             this.extraheaderConfigKey = `http.${serverUrl.origin}/.extraheader`;
-            // Backup checkout@v6 credential files if they exist
-            yield this.hideCredentialFiles();
-            // Save and unset persisted extraheader credential in git config if it exists
+            // Save and unset persisted extraheader credential in git config if it exists (old-style auth)
+            // Note: checkout@v6 uses credentials files with includeIf, so we don't need to
+            // manipulate those - they work independently via git's include mechanism
             this.persistedExtraheaderConfigValue = yield this.getAndUnset();
         });
     }
     restorePersistedAuth() {
         return __awaiter(this, void 0, void 0, function* () {
-            // Restore checkout@v6 credential files if they were backed up
-            yield this.unhideCredentialFiles();
+            // Restore old-style extraheader config if it was persisted
             if (this.persistedExtraheaderConfigValue) {
                 try {
                     yield this.setExtraheaderConfig(this.persistedExtraheaderConfigValue);
@@ -1213,69 +1273,160 @@ class GitConfigHelper {
     }
     configureToken(token) {
         return __awaiter(this, void 0, void 0, function* () {
-            // Encode and configure the basic credential for HTTPS access
+            // Encode the basic credential for HTTPS access
             const basicCredential = Buffer.from(`x-access-token:${token}`, 'utf8').toString('base64');
             core.setSecret(basicCredential);
             const extraheaderConfigValue = `AUTHORIZATION: basic ${basicCredential}`;
-            yield this.setExtraheaderConfig(extraheaderConfigValue);
+            // Get or create the credentials config file path
+            const credentialsConfigPath = this.getCredentialsConfigPath();
+            // Write placeholder to the separate credentials config file using git config.
+            // This approach avoids the credential being captured by process creation audit events,
+            // which are commonly logged. For more information, refer to
+            // https://docs.microsoft.com/en-us/windows-server/identity/ad-ds/manage/component-updates/command-line-process-auditing
+            yield this.git.config(this.extraheaderConfigKey, this.extraheaderConfigPlaceholderValue, false, // globalConfig
+            false, // add
+            credentialsConfigPath);
+            // Replace the placeholder in the credentials config file
+            let content = (yield fs.promises.readFile(credentialsConfigPath)).toString();
+            const placeholderIndex = content.indexOf(this.extraheaderConfigPlaceholderValue);
+            if (placeholderIndex < 0 ||
+                placeholderIndex !=
+                    content.lastIndexOf(this.extraheaderConfigPlaceholderValue)) {
+                throw new Error(`Unable to replace auth placeholder in ${credentialsConfigPath}`);
+            }
+            content = content.replace(this.extraheaderConfigPlaceholderValue, extraheaderConfigValue);
+            yield fs.promises.writeFile(credentialsConfigPath, content);
+            // Configure includeIf entries to reference the credentials config file
+            yield this.configureIncludeIf(credentialsConfigPath);
         });
     }
     removeAuth() {
         return __awaiter(this, void 0, void 0, function* () {
+            // Remove old-style extraheader config if it exists
             yield this.getAndUnset();
+            // Remove includeIf entries that point to git-credentials-*.config files
+            // and clean up the credentials config files
+            yield this.removeIncludeIfCredentials();
         });
     }
+    /**
+     * Gets or creates the path to the credentials config file in RUNNER_TEMP.
+     * @returns The absolute path to the credentials config file
+     */
+    getCredentialsConfigPath() {
+        if (this.credentialsConfigPath) {
+            return this.credentialsConfigPath;
+        }
+        const runnerTemp = process.env['RUNNER_TEMP'] || '';
+        if (!runnerTemp) {
+            throw new Error('RUNNER_TEMP is not defined');
+        }
+        // Create a unique filename for this action instance
+        const configFileName = `git-credentials-${(0, uuid_1.v4)()}.config`;
+        this.credentialsConfigPath = path.join(runnerTemp, configFileName);
+        core.debug(`Credentials config path: ${this.credentialsConfigPath}`);
+        return this.credentialsConfigPath;
+    }
+    /**
+     * Configures includeIf entries in the local git config to reference the credentials file.
+     * Sets up entries for both host and container paths to support Docker container actions.
+     */
+    configureIncludeIf(credentialsConfigPath) {
+        return __awaiter(this, void 0, void 0, function* () {
+            // Host git directory
+            const gitDir = yield this.git.getGitDirectory();
+            let hostGitDir = path.join(this.workingDirectory, gitDir);
+            hostGitDir = hostGitDir.replace(/\\/g, '/'); // Use forward slashes, even on Windows
+            // Configure host includeIf
+            const hostIncludeKey = `includeIf.gitdir:${hostGitDir}.path`;
+            yield this.git.config(hostIncludeKey, credentialsConfigPath);
+            // Configure host includeIf for worktrees
+            const hostWorktreeIncludeKey = `includeIf.gitdir:${hostGitDir}/worktrees/*.path`;
+            yield this.git.config(hostWorktreeIncludeKey, credentialsConfigPath);
+            // Container paths for Docker container actions
+            const githubWorkspace = process.env['GITHUB_WORKSPACE'];
+            if (githubWorkspace) {
+                let relativePath = path.relative(githubWorkspace, this.workingDirectory);
+                relativePath = relativePath.replace(/\\/g, '/'); // Use forward slashes, even on Windows
+                const containerGitDir = path.posix.join('/github/workspace', relativePath, '.git');
+                // Container credentials config path
+                const containerCredentialsPath = path.posix.join('/github/runner_temp', path.basename(credentialsConfigPath));
+                // Configure container includeIf
+                const containerIncludeKey = `includeIf.gitdir:${containerGitDir}.path`;
+                yield this.git.config(containerIncludeKey, containerCredentialsPath);
+                // Configure container includeIf for worktrees
+                const containerWorktreeIncludeKey = `includeIf.gitdir:${containerGitDir}/worktrees/*.path`;
+                yield this.git.config(containerWorktreeIncludeKey, containerCredentialsPath);
+            }
+        });
+    }
+    /**
+     * Removes the includeIf entry and credentials config file created by this action instance.
+     * Only cleans up the specific credentials file tracked in this.credentialsConfigPath,
+     * leaving credentials created by other actions (e.g., actions/checkout) intact.
+     */
+    removeIncludeIfCredentials() {
+        return __awaiter(this, void 0, void 0, function* () {
+            // Only clean up if this action instance created a credentials config file
+            if (!this.credentialsConfigPath) {
+                return;
+            }
+            try {
+                // Get all includeIf.gitdir keys from local config
+                const keys = yield this.git.tryGetConfigKeys('^includeIf\\.gitdir:');
+                for (const key of keys) {
+                    // Get all values for this key
+                    const values = yield this.git.tryGetConfigValues(key);
+                    for (const value of values) {
+                        // Only remove entries pointing to our specific credentials file
+                        if (value === this.credentialsConfigPath) {
+                            yield this.git.tryConfigUnsetValue(key, value);
+                            core.debug(`Removed includeIf entry: ${key} = ${value}`);
+                        }
+                    }
+                }
+            }
+            catch (e) {
+                // Ignore errors during cleanup
+                core.debug(`Error during includeIf cleanup: ${utils.getErrorMessage(e)}`);
+            }
+            // Delete only our credentials config file
+            const runnerTemp = process.env['RUNNER_TEMP'];
+            const resolvedCredentialsPath = path.resolve(this.credentialsConfigPath);
+            const resolvedRunnerTemp = runnerTemp ? path.resolve(runnerTemp) : '';
+            if (resolvedRunnerTemp &&
+                resolvedCredentialsPath.startsWith(resolvedRunnerTemp + path.sep)) {
+                try {
+                    yield fs.promises.unlink(this.credentialsConfigPath);
+                    core.info(`Removed credentials config file: ${this.credentialsConfigPath}`);
+                }
+                catch (e) {
+                    core.debug(`Could not remove credentials file ${this.credentialsConfigPath}: ${utils.getErrorMessage(e)}`);
+                }
+            }
+        });
+    }
+    /**
+     * Sets extraheader config directly in .git/config (old-style auth).
+     * Used only for restoring persisted credentials from checkout@v4/v5.
+     */
     setExtraheaderConfig(extraheaderConfigValue) {
         return __awaiter(this, void 0, void 0, function* () {
             // Configure a placeholder value. This approach avoids the credential being captured
             // by process creation audit events, which are commonly logged. For more information,
             // refer to https://docs.microsoft.com/en-us/windows-server/identity/ad-ds/manage/component-updates/command-line-process-auditing
-            // See https://github.com/actions/checkout/blob/main/src/git-auth-helper.ts#L267-L274
             yield this.git.config(this.extraheaderConfigKey, this.extraheaderConfigPlaceholderValue);
-            // Replace the placeholder
-            yield this.gitConfigStringReplace(this.extraheaderConfigPlaceholderValue, extraheaderConfigValue);
-        });
-    }
-    hideCredentialFiles() {
-        return __awaiter(this, void 0, void 0, function* () {
-            // Temporarily hide checkout@v6 credential files to avoid duplicate auth headers
-            const runnerTemp = process.env['RUNNER_TEMP'];
-            if (!runnerTemp) {
-                return;
+            // Replace the placeholder in the local git config
+            const gitDir = yield this.git.getGitDirectory();
+            const gitConfigPath = path.join(this.workingDirectory, gitDir, 'config');
+            let content = (yield fs.promises.readFile(gitConfigPath)).toString();
+            const index = content.indexOf(this.extraheaderConfigPlaceholderValue);
+            if (index < 0 ||
+                index != content.lastIndexOf(this.extraheaderConfigPlaceholderValue)) {
+                throw new Error(`Unable to replace '${this.extraheaderConfigPlaceholderValue}' in ${gitConfigPath}`);
             }
-            try {
-                const files = yield fs.promises.readdir(runnerTemp);
-                for (const file of files) {
-                    if (file.startsWith('git-credentials-') && file.endsWith('.config')) {
-                        const sourcePath = path.join(runnerTemp, file);
-                        const backupPath = `${sourcePath}.bak`;
-                        yield fs.promises.rename(sourcePath, backupPath);
-                        this.backedUpCredentialFiles.push(backupPath);
-                        core.info(`Temporarily hiding checkout credential file: ${file} (will be restored after)`);
-                    }
-                }
-            }
-            catch (e) {
-                // If directory doesn't exist or we can't read it, just continue
-                core.debug(`Could not backup credential files: ${utils.getErrorMessage(e)}`);
-            }
-        });
-    }
-    unhideCredentialFiles() {
-        return __awaiter(this, void 0, void 0, function* () {
-            // Restore checkout@v6 credential files that were backed up
-            for (const backupPath of this.backedUpCredentialFiles) {
-                try {
-                    const originalPath = backupPath.replace(/\.bak$/, '');
-                    yield fs.promises.rename(backupPath, originalPath);
-                    const fileName = path.basename(originalPath);
-                    core.info(`Restored checkout credential file: ${fileName}`);
-                }
-                catch (e) {
-                    core.warning(`Failed to restore credential file ${backupPath}: ${utils.getErrorMessage(e)}`);
-                }
-            }
-            this.backedUpCredentialFiles = [];
+            content = content.replace(this.extraheaderConfigPlaceholderValue, extraheaderConfigValue);
+            yield fs.promises.writeFile(gitConfigPath, content);
         });
     }
     getAndUnset() {
@@ -1294,21 +1445,6 @@ class GitConfigHelper {
             return configValue;
         });
     }
-    gitConfigStringReplace(find, replace) {
-        return __awaiter(this, void 0, void 0, function* () {
-            if (this.gitConfigPath.length === 0) {
-                const gitDir = yield this.git.getGitDirectory();
-                this.gitConfigPath = path.join(this.workingDirectory, gitDir, 'config');
-            }
-            let content = (yield fs.promises.readFile(this.gitConfigPath)).toString();
-            const index = content.indexOf(find);
-            if (index < 0 || index != content.lastIndexOf(find)) {
-                throw new Error(`Unable to replace '${find}' in ${this.gitConfigPath}`);
-            }
-            content = content.replace(find, replace);
-            yield fs.promises.writeFile(this.gitConfigPath, content);
-        });
-    }
 }
 exports.GitConfigHelper = GitConfigHelper;
 

src/git-command-manager.ts

@@ -96,9 +96,15 @@ export class GitCommandManager {
     configKey: string,
     configValue: string,
     globalConfig?: boolean,
-    add?: boolean
+    add?: boolean,
+    configFile?: string
   ): Promise<void> {
-    const args: string[] = ['config', globalConfig ? '--global' : '--local']
+    const args: string[] = ['config']
+    if (configFile) {
+      args.push('--file', configFile)
+    } else {
+      args.push(globalConfig ? '--global' : '--local')
+    }
     if (add) {
       args.push('--add')
     }
@@ -350,6 +356,67 @@ export class GitCommandManager {
     return output.exitCode === 0
   }
 
+  async tryConfigUnsetValue(
+    configKey: string,
+    configValue: string,
+    globalConfig?: boolean,
+    configFile?: string
+  ): Promise<boolean> {
+    const args = ['config']
+    if (configFile) {
+      args.push('--file', configFile)
+    } else {
+      args.push(globalConfig ? '--global' : '--local')
+    }
+    args.push('--fixed-value', '--unset', configKey, configValue)
+    const output = await this.exec(args, {allowAllExitCodes: true})
+    return output.exitCode === 0
+  }
+
+  async tryGetConfigValues(
+    configKey: string,
+    globalConfig?: boolean,
+    configFile?: string
+  ): Promise<string[]> {
+    const args = ['config']
+    if (configFile) {
+      args.push('--file', configFile)
+    } else {
+      args.push(globalConfig ? '--global' : '--local')
+    }
+    args.push('--get-all', configKey)
+    const output = await this.exec(args, {allowAllExitCodes: true})
+    if (output.exitCode !== 0) {
+      return []
+    }
+    return output.stdout
+      .trim()
+      .split('\n')
+      .filter(value => value.trim())
+  }
+
+  async tryGetConfigKeys(
+    pattern: string,
+    globalConfig?: boolean,
+    configFile?: string
+  ): Promise<string[]> {
+    const args = ['config']
+    if (configFile) {
+      args.push('--file', configFile)
+    } else {
+      args.push(globalConfig ? '--global' : '--local')
+    }
+    args.push('--name-only', '--get-regexp', pattern)
+    const output = await this.exec(args, {allowAllExitCodes: true})
+    if (output.exitCode !== 0) {
+      return []
+    }
+    return output.stdout
+      .trim()
+      .split('\n')
+      .filter(key => key.trim())
+  }
+
   async tryGetRemoteUrl(): Promise<string> {
     const output = await this.exec(
       ['config', '--local', '--get', 'remote.origin.url'],

src/git-config-helper.ts

@@ -4,6 +4,7 @@ import {GitCommandManager} from './git-command-manager'
 import * as path from 'path'
 import {URL} from 'url'
 import * as utils from './utils'
+import {v4 as uuid} from 'uuid'
 
 interface GitRemote {
   hostname: string
@@ -13,7 +14,6 @@ interface GitRemote {
 
 export class GitConfigHelper {
   private git: GitCommandManager
-  private gitConfigPath = ''
   private workingDirectory: string
   private safeDirectoryConfigKey = 'safe.directory'
   private safeDirectoryAdded = false
@@ -22,7 +22,8 @@ export class GitConfigHelper {
   private extraheaderConfigPlaceholderValue = 'AUTHORIZATION: basic ***'
   private extraheaderConfigValueRegex = '^AUTHORIZATION:'
   private persistedExtraheaderConfigValue = ''
-  private backedUpCredentialFiles: string[] = []
+  // Path to the credentials config file in RUNNER_TEMP (new v6-style auth)
+  private credentialsConfigPath = ''
 
   private constructor(git: GitCommandManager) {
     this.git = git
@@ -122,15 +123,14 @@ export class GitConfigHelper {
   async savePersistedAuth(): Promise<void> {
     const serverUrl = new URL(`https://${this.getGitRemote().hostname}`)
     this.extraheaderConfigKey = `http.${serverUrl.origin}/.extraheader`
-    // Backup checkout@v6 credential files if they exist
-    await this.hideCredentialFiles()
-    // Save and unset persisted extraheader credential in git config if it exists
+    // Save and unset persisted extraheader credential in git config if it exists (old-style auth)
+    // Note: checkout@v6 uses credentials files with includeIf, so we don't need to
+    // manipulate those - they work independently via git's include mechanism
     this.persistedExtraheaderConfigValue = await this.getAndUnset()
   }
 
   async restorePersistedAuth(): Promise<void> {
-    // Restore checkout@v6 credential files if they were backed up
-    await this.unhideCredentialFiles()
+    // Restore old-style extraheader config if it was persisted
     if (this.persistedExtraheaderConfigValue) {
       try {
         await this.setExtraheaderConfig(this.persistedExtraheaderConfigValue)
@@ -142,81 +142,218 @@ export class GitConfigHelper {
   }
 
   async configureToken(token: string): Promise<void> {
-    // Encode and configure the basic credential for HTTPS access
+    // Encode the basic credential for HTTPS access
     const basicCredential = Buffer.from(
       `x-access-token:${token}`,
       'utf8'
     ).toString('base64')
     core.setSecret(basicCredential)
     const extraheaderConfigValue = `AUTHORIZATION: basic ${basicCredential}`
-    await this.setExtraheaderConfig(extraheaderConfigValue)
+
+    // Get or create the credentials config file path
+    const credentialsConfigPath = this.getCredentialsConfigPath()
+
+    // Write placeholder to the separate credentials config file using git config.
+    // This approach avoids the credential being captured by process creation audit events,
+    // which are commonly logged. For more information, refer to
+    // https://docs.microsoft.com/en-us/windows-server/identity/ad-ds/manage/component-updates/command-line-process-auditing
+    await this.git.config(
+      this.extraheaderConfigKey,
+      this.extraheaderConfigPlaceholderValue,
+      false, // globalConfig
+      false, // add
+      credentialsConfigPath
+    )
+
+    // Replace the placeholder in the credentials config file
+    let content = (await fs.promises.readFile(credentialsConfigPath)).toString()
+    const placeholderIndex = content.indexOf(
+      this.extraheaderConfigPlaceholderValue
+    )
+    if (
+      placeholderIndex < 0 ||
+      placeholderIndex !=
+        content.lastIndexOf(this.extraheaderConfigPlaceholderValue)
+    ) {
+      throw new Error(
+        `Unable to replace auth placeholder in ${credentialsConfigPath}`
+      )
+    }
+    content = content.replace(
+      this.extraheaderConfigPlaceholderValue,
+      extraheaderConfigValue
+    )
+    await fs.promises.writeFile(credentialsConfigPath, content)
+
+    // Configure includeIf entries to reference the credentials config file
+    await this.configureIncludeIf(credentialsConfigPath)
   }
 
   async removeAuth(): Promise<void> {
+    // Remove old-style extraheader config if it exists
     await this.getAndUnset()
+
+    // Remove includeIf entries that point to git-credentials-*.config files
+    // and clean up the credentials config files
+    await this.removeIncludeIfCredentials()
   }
 
+  /**
+   * Gets or creates the path to the credentials config file in RUNNER_TEMP.
+   * @returns The absolute path to the credentials config file
+   */
+  private getCredentialsConfigPath(): string {
+    if (this.credentialsConfigPath) {
+      return this.credentialsConfigPath
+    }
+
+    const runnerTemp = process.env['RUNNER_TEMP'] || ''
+    if (!runnerTemp) {
+      throw new Error('RUNNER_TEMP is not defined')
+    }
+
+    // Create a unique filename for this action instance
+    const configFileName = `git-credentials-${uuid()}.config`
+    this.credentialsConfigPath = path.join(runnerTemp, configFileName)
+
+    core.debug(`Credentials config path: ${this.credentialsConfigPath}`)
+    return this.credentialsConfigPath
+  }
+
+  /**
+   * Configures includeIf entries in the local git config to reference the credentials file.
+   * Sets up entries for both host and container paths to support Docker container actions.
+   */
+  private async configureIncludeIf(
+    credentialsConfigPath: string
+  ): Promise<void> {
+    // Host git directory
+    const gitDir = await this.git.getGitDirectory()
+    let hostGitDir = path.join(this.workingDirectory, gitDir)
+    hostGitDir = hostGitDir.replace(/\\/g, '/') // Use forward slashes, even on Windows
+
+    // Configure host includeIf
+    const hostIncludeKey = `includeIf.gitdir:${hostGitDir}.path`
+    await this.git.config(hostIncludeKey, credentialsConfigPath)
+
+    // Configure host includeIf for worktrees
+    const hostWorktreeIncludeKey = `includeIf.gitdir:${hostGitDir}/worktrees/*.path`
+    await this.git.config(hostWorktreeIncludeKey, credentialsConfigPath)
+
+    // Container paths for Docker container actions
+    const githubWorkspace = process.env['GITHUB_WORKSPACE']
+    if (githubWorkspace) {
+      let relativePath = path.relative(githubWorkspace, this.workingDirectory)
+      relativePath = relativePath.replace(/\\/g, '/') // Use forward slashes, even on Windows
+      const containerGitDir = path.posix.join(
+        '/github/workspace',
+        relativePath,
+        '.git'
+      )
+
+      // Container credentials config path
+      const containerCredentialsPath = path.posix.join(
+        '/github/runner_temp',
+        path.basename(credentialsConfigPath)
+      )
+
+      // Configure container includeIf
+      const containerIncludeKey = `includeIf.gitdir:${containerGitDir}.path`
+      await this.git.config(containerIncludeKey, containerCredentialsPath)
+
+      // Configure container includeIf for worktrees
+      const containerWorktreeIncludeKey = `includeIf.gitdir:${containerGitDir}/worktrees/*.path`
+      await this.git.config(
+        containerWorktreeIncludeKey,
+        containerCredentialsPath
+      )
+    }
+  }
+
+  /**
+   * Removes the includeIf entry and credentials config file created by this action instance.
+   * Only cleans up the specific credentials file tracked in this.credentialsConfigPath,
+   * leaving credentials created by other actions (e.g., actions/checkout) intact.
+   */
+  private async removeIncludeIfCredentials(): Promise<void> {
+    // Only clean up if this action instance created a credentials config file
+    if (!this.credentialsConfigPath) {
+      return
+    }
+
+    try {
+      // Get all includeIf.gitdir keys from local config
+      const keys = await this.git.tryGetConfigKeys('^includeIf\\.gitdir:')
+
+      for (const key of keys) {
+        // Get all values for this key
+        const values = await this.git.tryGetConfigValues(key)
+        for (const value of values) {
+          // Only remove entries pointing to our specific credentials file
+          if (value === this.credentialsConfigPath) {
+            await this.git.tryConfigUnsetValue(key, value)
+            core.debug(`Removed includeIf entry: ${key} = ${value}`)
+          }
+        }
+      }
+    } catch (e) {
+      // Ignore errors during cleanup
+      core.debug(`Error during includeIf cleanup: ${utils.getErrorMessage(e)}`)
+    }
+
+    // Delete only our credentials config file
+    const runnerTemp = process.env['RUNNER_TEMP']
+    const resolvedCredentialsPath = path.resolve(this.credentialsConfigPath)
+    const resolvedRunnerTemp = runnerTemp ? path.resolve(runnerTemp) : ''
+    if (
+      resolvedRunnerTemp &&
+      resolvedCredentialsPath.startsWith(resolvedRunnerTemp + path.sep)
+    ) {
+      try {
+        await fs.promises.unlink(this.credentialsConfigPath)
+        core.info(
+          `Removed credentials config file: ${this.credentialsConfigPath}`
+        )
+      } catch (e) {
+        core.debug(
+          `Could not remove credentials file ${this.credentialsConfigPath}: ${utils.getErrorMessage(e)}`
+        )
+      }
+    }
+  }
+
+  /**
+   * Sets extraheader config directly in .git/config (old-style auth).
+   * Used only for restoring persisted credentials from checkout@v4/v5.
+   */
   private async setExtraheaderConfig(
     extraheaderConfigValue: string
   ): Promise<void> {
     // Configure a placeholder value. This approach avoids the credential being captured
     // by process creation audit events, which are commonly logged. For more information,
     // refer to https://docs.microsoft.com/en-us/windows-server/identity/ad-ds/manage/component-updates/command-line-process-auditing
-    // See https://github.com/actions/checkout/blob/main/src/git-auth-helper.ts#L267-L274
     await this.git.config(
       this.extraheaderConfigKey,
       this.extraheaderConfigPlaceholderValue
     )
-    // Replace the placeholder
-    await this.gitConfigStringReplace(
+    // Replace the placeholder in the local git config
+    const gitDir = await this.git.getGitDirectory()
+    const gitConfigPath = path.join(this.workingDirectory, gitDir, 'config')
+    let content = (await fs.promises.readFile(gitConfigPath)).toString()
+    const index = content.indexOf(this.extraheaderConfigPlaceholderValue)
+    if (
+      index < 0 ||
+      index != content.lastIndexOf(this.extraheaderConfigPlaceholderValue)
+    ) {
+      throw new Error(
+        `Unable to replace '${this.extraheaderConfigPlaceholderValue}' in ${gitConfigPath}`
+      )
+    }
+    content = content.replace(
       this.extraheaderConfigPlaceholderValue,
       extraheaderConfigValue
     )
-  }
-
-  private async hideCredentialFiles(): Promise<void> {
-    // Temporarily hide checkout@v6 credential files to avoid duplicate auth headers
-    const runnerTemp = process.env['RUNNER_TEMP']
-    if (!runnerTemp) {
-      return
-    }
-
-    try {
-      const files = await fs.promises.readdir(runnerTemp)
-      for (const file of files) {
-        if (file.startsWith('git-credentials-') && file.endsWith('.config')) {
-          const sourcePath = path.join(runnerTemp, file)
-          const backupPath = `${sourcePath}.bak`
-          await fs.promises.rename(sourcePath, backupPath)
-          this.backedUpCredentialFiles.push(backupPath)
-          core.info(
-            `Temporarily hiding checkout credential file: ${file} (will be restored after)`
-          )
-        }
-      }
-    } catch (e) {
-      // If directory doesn't exist or we can't read it, just continue
-      core.debug(
-        `Could not backup credential files: ${utils.getErrorMessage(e)}`
-      )
-    }
-  }
-
-  private async unhideCredentialFiles(): Promise<void> {
-    // Restore checkout@v6 credential files that were backed up
-    for (const backupPath of this.backedUpCredentialFiles) {
-      try {
-        const originalPath = backupPath.replace(/\.bak$/, '')
-        await fs.promises.rename(backupPath, originalPath)
-        const fileName = path.basename(originalPath)
-        core.info(`Restored checkout credential file: ${fileName}`)
-      } catch (e) {
-        core.warning(
-          `Failed to restore credential file ${backupPath}: ${utils.getErrorMessage(e)}`
-        )
-      }
-    }
-    this.backedUpCredentialFiles = []
+    await fs.promises.writeFile(gitConfigPath, content)
   }
 
   private async getAndUnset(): Promise<string> {
@@ -247,21 +384,4 @@ export class GitConfigHelper {
     }
     return configValue
   }
-
-  private async gitConfigStringReplace(
-    find: string,
-    replace: string
-  ): Promise<void> {
-    if (this.gitConfigPath.length === 0) {
-      const gitDir = await this.git.getGitDirectory()
-      this.gitConfigPath = path.join(this.workingDirectory, gitDir, 'config')
-    }
-    let content = (await fs.promises.readFile(this.gitConfigPath)).toString()
-    const index = content.indexOf(find)
-    if (index < 0 || index != content.lastIndexOf(find)) {
-      throw new Error(`Unable to replace '${find}' in ${this.gitConfigPath}`)
-    }
-    content = content.replace(find, replace)
-    await fs.promises.writeFile(this.gitConfigPath, content)
-  }
 }