backport fixes to releases-v2 (#2526)

* backport fixes to releases-v2

* fix dist/index.js

.github/workflows/check-dist.yml

@@ -22,12 +22,12 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v2
 
-      - name: Set Node.js 16.x
+      - name: Set Node.js 12.x
         uses: actions/setup-node@v1
         with:
-          node-version: 16.x
+          node-version: 12.x
 
       - name: Install dependencies
         run: npm ci
@@ -44,7 +44,7 @@ jobs:
           fi
 
       # If dist/ was different than expected, upload the expected version as an artifact
-      - uses: actions/upload-artifact@v2
+      - uses: actions/upload-artifact@v4
         if: ${{ failure() && steps.diff.conclusion == 'failure' }}
         with:
           name: dist

.github/workflows/codeql-analysis.yml

@@ -39,7 +39,7 @@ jobs:
 
     steps:
     - name: Checkout repository
-      uses: actions/checkout@v3
+      uses: actions/checkout@v2
 
     - name: Initialize CodeQL
       uses: github/codeql-action/init@v1

.github/workflows/licensed.yml

@@ -9,6 +9,6 @@ jobs:
     runs-on: ubuntu-latest
     name: Check licenses
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v2
       - run: npm ci
       - run: npm run licensed-check

.github/workflows/test.yml

@@ -13,8 +13,8 @@ jobs:
     steps:
       - uses: actions/setup-node@v1
         with:
-          node-version: 16.x
+          node-version: 12.x
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v2
       - run: npm ci
       - run: npm run build
       - run: npm run format-check
@@ -32,7 +32,7 @@ jobs:
     steps:
       # Clone this repo
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v2
 
       # Basic checkout
       - name: Checkout basic
@@ -142,7 +142,7 @@ jobs:
       options: --dns 127.0.0.1
     services:
       squid-proxy:
-        image: datadog/squid:latest
+        image: ubuntu/squid:latest
         ports:
           - 3128:3128
     env:
@@ -150,7 +150,7 @@ jobs:
     steps:
       # Clone this repo
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v2
 
       # Basic checkout using git
       - name: Checkout basic
@@ -182,7 +182,7 @@ jobs:
     steps:
       # Clone this repo
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v2
 
       # Basic checkout using git
       - name: Checkout basic
@@ -205,3 +205,41 @@ jobs:
           path: basic
       - name: Verify basic
         run: __test__/verify-basic.sh --archive
+    
+  test-git-container:
+    runs-on: ubuntu-latest
+    container: bitnami/git:latest
+    steps:
+      # Clone this repo
+      - name: Checkout
+        uses: actions/checkout@v3
+        with:
+          path: v3
+
+      # Basic checkout using git
+      - name: Checkout basic
+        uses: ./v3
+        with:
+          ref: test-data/v2/basic
+      - name: Verify basic
+        run: |
+          if [ ! -f "./basic-file.txt" ]; then
+              echo "Expected basic file does not exist"
+              exit 1
+          fi
+
+          # Verify .git folder
+          if [ ! -d "./.git" ]; then
+            echo "Expected ./.git folder to exist"
+            exit 1
+          fi
+
+          # Verify auth token
+          git config --global --add safe.directory "*"
+          git fetch --no-tags --depth=1 origin +refs/heads/main:refs/remotes/origin/main
+
+      # needed to make checkout post cleanup succeed
+      - name: Fix Checkout v3
+        uses: actions/checkout@v3
+        with:
+          path: v3

CHANGELOG.md

@@ -1,17 +1,19 @@
 # Changelog
 
-## v3.0.1
+## v2.5.0
-- [Fixed an issue where checkout failed to run in container jobs due to the new git setting `safe.directory`](https://github.com/actions/checkout/pull/762)
+- [Bump @actions/core to v1.10.0](https://github.com/actions/checkout/pull/962)
-- [Bumped various npm package versions](https://github.com/actions/checkout/pull/744)
 
-## v3.0.0
+## v2.4.2
+- [Add input `set-safe-directory`](https://github.com/actions/checkout/pull/776)
 
-- [Update to node 16](https://github.com/actions/checkout/pull/689)
+## v2.4.1
+- [Set the safe directory option on git to prevent git commands failing when running in containers](https://github.com/actions/checkout/pull/762)
 
 ## v2.3.1
 
 - [Fix default branch resolution for .wiki and when using SSH](https://github.com/actions/checkout/pull/284)
 
+
 ## v2.3.0
 
 - [Fallback to the default branch](https://github.com/actions/checkout/pull/278)

README.md

@@ -2,7 +2,7 @@
   <a href="https://github.com/actions/checkout"><img alt="GitHub Actions status" src="https://github.com/actions/checkout/workflows/test-local/badge.svg"></a>
 </p>
 
-# Checkout V3
+# Checkout V2
 
 This action checks-out your repository under `$GITHUB_WORKSPACE`, so your workflow can access it.
 
@@ -14,14 +14,27 @@ When Git 2.18 or higher is not in your PATH, falls back to the REST API to downl
 
 # What's new
 
-- Updated to the node16 runtime by default
+- Improved performance
-  - This requires a minimum [Actions Runner](https://github.com/actions/runner/releases/tag/v2.285.0) version of v2.285.0 to run, which is by default available in GHES 3.4 or later.
+  - Fetches only a single commit by default
+- Script authenticated git commands
+  - Auth token persisted in the local git config
+- Supports SSH
+- Creates a local branch
+  - No longer detached HEAD when checking out a branch
+- Improved layout
+  - The input `path` is always relative to $GITHUB_WORKSPACE
+  - Aligns better with container actions, where $GITHUB_WORKSPACE gets mapped in
+- Fallback to REST API download
+  - When Git 2.18 or higher is not in the PATH, the REST API will be used to download the files
+  - When using a job container, the container's PATH is used
+
+Refer [here](https://github.com/actions/checkout/blob/v1/README.md) for previous versions.
 
 # Usage
 
 <!-- start usage -->
 ```yaml
-- uses: actions/checkout@v3
+- uses: actions/checkout@v2
   with:
     # Repository name with owner. For example, actions/checkout
     # Default: ${{ github.repository }}
@@ -92,6 +105,20 @@ When Git 2.18 or higher is not in your PATH, falls back to the REST API to downl
     #
     # Default: false
     submodules: ''
+
+    # Add repository path as safe.directory for Git global config by running `git
+    # config --global --add safe.directory <path>`
+    # Default: true
+    set-safe-directory: ''
+
+    # Required to check out fork pull request code from a workflow triggered by
+    # `pull_request_target` or `workflow_run`. These workflows run with the base
+    # repository's GITHUB_TOKEN, secrets, default-branch cache scope, and runner
+    # access; fetching and executing a fork's code in that trusted context commonly
+    # leads to "pwn request" vulnerabilities. Set to `true` only after reviewing the
+    # risks at https://gh.io/securely-using-pull_request_target.
+    # Default: false
+    allow-unsafe-pr-checkout: ''
 ```
 <!-- end usage -->
 
@@ -110,7 +137,7 @@ When Git 2.18 or higher is not in your PATH, falls back to the REST API to downl
 ## Fetch all history for all tags and branches
 
 ```yaml
-- uses: actions/checkout@v3
+- uses: actions/checkout@v2
   with:
     fetch-depth: 0
 ```
@@ -118,7 +145,7 @@ When Git 2.18 or higher is not in your PATH, falls back to the REST API to downl
 ## Checkout a different branch
 
 ```yaml
-- uses: actions/checkout@v3
+- uses: actions/checkout@v2
   with:
     ref: my-branch
 ```
@@ -126,7 +153,7 @@ When Git 2.18 or higher is not in your PATH, falls back to the REST API to downl
 ## Checkout HEAD^
 
 ```yaml
-- uses: actions/checkout@v3
+- uses: actions/checkout@v2
   with:
     fetch-depth: 2
 - run: git checkout HEAD^
@@ -136,12 +163,12 @@ When Git 2.18 or higher is not in your PATH, falls back to the REST API to downl
 
 ```yaml
 - name: Checkout
-  uses: actions/checkout@v3
+  uses: actions/checkout@v2
   with:
     path: main
 
 - name: Checkout tools repo
-  uses: actions/checkout@v3
+  uses: actions/checkout@v2
   with:
     repository: my-org/my-tools
     path: my-tools
@@ -151,10 +178,10 @@ When Git 2.18 or higher is not in your PATH, falls back to the REST API to downl
 
 ```yaml
 - name: Checkout
-  uses: actions/checkout@v3
+  uses: actions/checkout@v2
 
 - name: Checkout tools repo
-  uses: actions/checkout@v3
+  uses: actions/checkout@v2
   with:
     repository: my-org/my-tools
     path: my-tools
@@ -164,12 +191,12 @@ When Git 2.18 or higher is not in your PATH, falls back to the REST API to downl
 
 ```yaml
 - name: Checkout
-  uses: actions/checkout@v3
+  uses: actions/checkout@v2
   with:
     path: main
 
 - name: Checkout private tools
-  uses: actions/checkout@v3
+  uses: actions/checkout@v2
   with:
     repository: my-org/my-private-tools
     token: ${{ secrets.GH_PAT }} # `GH_PAT` is a secret that contains your PAT
@@ -182,7 +209,7 @@ When Git 2.18 or higher is not in your PATH, falls back to the REST API to downl
 ## Checkout pull request HEAD commit instead of merge commit
 
 ```yaml
-- uses: actions/checkout@v3
+- uses: actions/checkout@v2
   with:
     ref: ${{ github.event.pull_request.head.sha }}
 ```
@@ -198,7 +225,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v2
 ```
 
 ## Push a commit using the built-in token
@@ -209,7 +236,7 @@ jobs:
   build:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v2
       - run: |
           date > generated.txt
           git config user.name github-actions

__test__/git-auth-helper.test.ts

@@ -777,7 +777,9 @@ async function setup(testName: string): Promise<void> {
     sshKey: sshPath ? 'some ssh private key' : '',
     sshKnownHosts: '',
     sshStrict: true,
-    workflowOrganizationId: 123456
+    workflowOrganizationId: 123456,
+    setSafeDirectory: true,
+    allowUnsafePrCheckout: false
   }
 }
 

__test__/input-helper.test.ts

@@ -12,15 +12,24 @@ const gitHubWorkspace = path.resolve('/checkout-tests/workspace')
 // Inputs for mock @actions/core
 let inputs = {} as any
 
+// Replicate @actions/core getInput behavior: it trims whitespace by default
+// (String.prototype.trim(), which strips characters such as a leading U+FEFF BOM)
+// unless trimWhitespace is explicitly set to false.
+const getInputImpl = (name: string, options?: {trimWhitespace?: boolean}) => {
+  const val = inputs[name] ?? ''
+  if (options && options.trimWhitespace === false) {
+    return val
+  }
+  return typeof val === 'string' ? val.trim() : val
+}
+
 // Shallow clone original @actions/github context
 let originalContext = {...github.context}
 
 describe('input-helper tests', () => {
   beforeAll(() => {
     // Mock getInput
-    jest.spyOn(core, 'getInput').mockImplementation((name: string) => {
+    jest.spyOn(core, 'getInput').mockImplementation(getInputImpl as any)
-      return inputs[name]
-    })
 
     // Mock error/warning/info/debug
     jest.spyOn(core, 'error').mockImplementation(jest.fn())
@@ -85,6 +94,8 @@ describe('input-helper tests', () => {
     expect(settings.repositoryName).toBe('some-repo')
     expect(settings.repositoryOwner).toBe('some-owner')
     expect(settings.repositoryPath).toBe(gitHubWorkspace)
+    expect(settings.setSafeDirectory).toBe(true)
+    expect(settings.allowUnsafePrCheckout).toBe(false)
   })
 
   it('qualifies ref', async () => {
@@ -134,8 +145,76 @@ describe('input-helper tests', () => {
     expect(settings.commit).toBeFalsy()
   })
 
+  it('does not reclassify a ref as sha when a BOM is prefixed', async () => {
+    // A fork branch named "<U+FEFF>" + 40 hex chars. core.getInput trims the
+    // BOM by default, which previously collapsed this into a bare SHA and
+    // bypassed the unsafe fork PR checkout guard.
+    inputs.ref = '\uFEFF522d932fae5296da51fdf431934425ecf891c6a2'
+    const settings: IGitSourceSettings = await inputHelper.getInputs()
+    expect(settings.commit).toBeFalsy()
+    expect(settings.ref).toBe('522d932fae5296da51fdf431934425ecf891c6a2')
+  })
+
+  it('treats a sha surrounded by ascii whitespace as a commit', async () => {
+    // ASCII whitespace can only come from the workflow author's YAML (git ref
+    // names cannot contain it), so trimming it and treating the value as a
+    // commit is safe.
+    inputs.ref = '  1111111111222222222233333333334444444444  '
+    const settings: IGitSourceSettings = await inputHelper.getInputs()
+    expect(settings.ref).toBeFalsy()
+    expect(settings.commit).toBe('1111111111222222222233333333334444444444')
+  })
+
   it('sets workflow organization ID', async () => {
     const settings: IGitSourceSettings = await inputHelper.getInputs()
     expect(settings.workflowOrganizationId).toBe(123456)
   })
+
+  describe('unsafe PR checkout guard', () => {
+    const forkPayload = {
+      repository: {id: 100},
+      pull_request: {
+        head: {
+          sha: '1234567890123456789012345678901234567890',
+          repo: {id: 200, full_name: 'attacker/fork'}
+        },
+        merge_commit_sha: 'aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa'
+      }
+    }
+
+    it('allows the default self-checkout on a fork pull_request_target', async () => {
+      const originalEvent = github.context.eventName
+      const originalPayload = github.context.payload
+      const originalSha = github.context.sha
+      try {
+        github.context.eventName = 'pull_request_target'
+        github.context.payload = forkPayload as any
+        // Simulate a rebase/fast-forward merge where the base tip (event SHA)
+        // equals the PR head SHA. The default self-checkout must still succeed.
+        github.context.sha = '1234567890123456789012345678901234567890'
+        const settings: IGitSourceSettings = await inputHelper.getInputs()
+        expect(settings.commit).toBe('1234567890123456789012345678901234567890')
+      } finally {
+        github.context.eventName = originalEvent
+        github.context.payload = originalPayload
+        github.context.sha = originalSha
+      }
+    })
+
+    it('refuses an explicit fork repository on pull_request_target', async () => {
+      const originalEvent = github.context.eventName
+      const originalPayload = github.context.payload
+      try {
+        github.context.eventName = 'pull_request_target'
+        github.context.payload = forkPayload as any
+        inputs.repository = 'attacker/fork'
+        await expect(inputHelper.getInputs()).rejects.toThrow(
+          /Refusing to check out fork pull request code/
+        )
+      } finally {
+        github.context.eventName = originalEvent
+        github.context.payload = originalPayload
+      }
+    })
+  })
 })

__test__/unsafe-pr-checkout-helper.test.ts

@@ -0,0 +1,267 @@
+import * as github from '@actions/github'
+import {assertSafePrCheckout} from '../lib/unsafe-pr-checkout-helper'
+
+// Shallow clone original @actions/github context
+const originalContext = {...github.context}
+const originalEventName = github.context.eventName
+const originalPayload = github.context.payload
+
+const BASE_REPO_ID = 100
+const FORK_REPO_ID = 200
+const PR_HEAD_SHA = '1111111111111111111111111111111111111111'
+const PR_MERGE_SHA = '2222222222222222222222222222222222222222'
+const SAFE_BASE_SHA = '3333333333333333333333333333333333333333'
+const WORKFLOW_RUN_HEAD_COMMIT_SHA = '4444444444444444444444444444444444444444'
+const BASE_QUALIFIED_REPO = 'some-owner/some-repo'
+const FORK_QUALIFIED_REPO = 'another-repo/fork'
+
+function setContext(eventName: string, payload: object): void {
+  ;(github.context as {eventName: string}).eventName = eventName
+  ;(github.context as {payload: object}).payload = payload
+}
+
+function forkPullRequestTargetPayload(): object {
+  return {
+    repository: {id: BASE_REPO_ID},
+    pull_request: {
+      head: {
+        sha: PR_HEAD_SHA,
+        repo: {id: FORK_REPO_ID, full_name: FORK_QUALIFIED_REPO}
+      },
+      merge_commit_sha: PR_MERGE_SHA
+    }
+  }
+}
+
+function sameRepoPullRequestTargetPayload(): object {
+  return {
+    repository: {id: BASE_REPO_ID},
+    pull_request: {
+      head: {
+        sha: PR_HEAD_SHA,
+        repo: {id: BASE_REPO_ID, full_name: BASE_QUALIFIED_REPO}
+      },
+      merge_commit_sha: PR_MERGE_SHA
+    }
+  }
+}
+
+function forkWorkflowRunPayload(): object {
+  return {
+    repository: {id: BASE_REPO_ID},
+    workflow_run: {
+      event: 'pull_request',
+      head_commit: {id: WORKFLOW_RUN_HEAD_COMMIT_SHA},
+      head_repository: {id: FORK_REPO_ID, full_name: FORK_QUALIFIED_REPO}
+    }
+  }
+}
+
+describe('unsafe-pr-checkout-helper', () => {
+  beforeAll(() => {
+    jest.spyOn(github.context, 'repo', 'get').mockReturnValue({
+      owner: 'some-owner',
+      repo: 'some-repo'
+    })
+  })
+
+  afterEach(() => {
+    ;(github.context as {eventName: string}).eventName = originalEventName
+    ;(github.context as {payload: object}).payload = originalPayload
+  })
+
+  afterAll(() => {
+    ;(github.context as {eventName: string}).eventName =
+      originalContext.eventName
+    ;(github.context as {payload: object}).payload = originalContext.payload
+    jest.restoreAllMocks()
+  })
+
+  it('allows pull_request events untouched', () => {
+    setContext('pull_request', forkPullRequestTargetPayload())
+    expect(() =>
+      assertSafePrCheckout({
+        qualifiedRepository: 'attacker/fork',
+        ref: 'refs/pull/1/merge',
+        commit: '',
+        allowUnsafePrCheckout: false
+      })
+    ).not.toThrow()
+  })
+
+  it('allows pull_request_target default checkout (base branch)', () => {
+    setContext('pull_request_target', forkPullRequestTargetPayload())
+    expect(() =>
+      assertSafePrCheckout({
+        qualifiedRepository: BASE_QUALIFIED_REPO,
+        ref: 'refs/heads/main',
+        commit: SAFE_BASE_SHA,
+        allowUnsafePrCheckout: false
+      })
+    ).not.toThrow()
+  })
+
+  it('allows same-repo pull_request_target checkout of PR head', () => {
+    setContext('pull_request_target', sameRepoPullRequestTargetPayload())
+    expect(() =>
+      assertSafePrCheckout({
+        qualifiedRepository: BASE_QUALIFIED_REPO,
+        ref: '',
+        commit: PR_HEAD_SHA,
+        allowUnsafePrCheckout: false
+      })
+    ).not.toThrow()
+  })
+
+  it('refuses pull_request_target fork PR head SHA checkout', () => {
+    setContext('pull_request_target', forkPullRequestTargetPayload())
+    expect(() =>
+      assertSafePrCheckout({
+        qualifiedRepository: BASE_QUALIFIED_REPO,
+        ref: '',
+        commit: PR_HEAD_SHA,
+        allowUnsafePrCheckout: false
+      })
+    ).toThrow(/Refusing to check out fork pull request code/)
+  })
+
+  it('refuses pull_request_target fork PR merge_commit_sha checkout', () => {
+    setContext('pull_request_target', forkPullRequestTargetPayload())
+    expect(() =>
+      assertSafePrCheckout({
+        qualifiedRepository: BASE_QUALIFIED_REPO,
+        ref: '',
+        commit: PR_MERGE_SHA,
+        allowUnsafePrCheckout: false
+      })
+    ).toThrow(/allow-unsafe-pr-checkout/)
+  })
+
+  it('refuses pull_request_target fork PR ref pattern (head)', () => {
+    setContext('pull_request_target', forkPullRequestTargetPayload())
+    expect(() =>
+      assertSafePrCheckout({
+        qualifiedRepository: BASE_QUALIFIED_REPO,
+        ref: 'refs/pull/42/head',
+        commit: '',
+        allowUnsafePrCheckout: false
+      })
+    ).toThrow()
+  })
+
+  it('refuses pull_request_target fork PR ref pattern (merge)', () => {
+    setContext('pull_request_target', forkPullRequestTargetPayload())
+    expect(() =>
+      assertSafePrCheckout({
+        qualifiedRepository: BASE_QUALIFIED_REPO,
+        ref: 'refs/pull/42/merge',
+        commit: '',
+        allowUnsafePrCheckout: false
+      })
+    ).toThrow()
+  })
+
+  it('refuses pull_request_target when repository points at the fork', () => {
+    setContext('pull_request_target', forkPullRequestTargetPayload())
+    expect(() =>
+      assertSafePrCheckout({
+        qualifiedRepository: FORK_QUALIFIED_REPO,
+        ref: 'refs/heads/main',
+        commit: '',
+        allowUnsafePrCheckout: false
+      })
+    ).toThrow()
+  })
+
+  it('allows pull_request_target checkout of an unrelated third-party repo', () => {
+    setContext('pull_request_target', forkPullRequestTargetPayload())
+    expect(() =>
+      assertSafePrCheckout({
+        qualifiedRepository: 'some-other/unrelated',
+        ref: 'refs/heads/main',
+        commit: '',
+        allowUnsafePrCheckout: false
+      })
+    ).not.toThrow()
+  })
+
+  it('refuses pull_request_target ignoring repository case differences', () => {
+    setContext('pull_request_target', forkPullRequestTargetPayload())
+    expect(() =>
+      assertSafePrCheckout({
+        qualifiedRepository: FORK_QUALIFIED_REPO.toUpperCase(),
+        ref: '',
+        commit: '',
+        allowUnsafePrCheckout: false
+      })
+    ).toThrow()
+  })
+
+  it('refuses pull_request_target ignoring commit SHA case differences', () => {
+    setContext('pull_request_target', forkPullRequestTargetPayload())
+    expect(() =>
+      assertSafePrCheckout({
+        qualifiedRepository: BASE_QUALIFIED_REPO,
+        ref: '',
+        commit: PR_HEAD_SHA.toUpperCase(),
+        allowUnsafePrCheckout: false
+      })
+    ).toThrow()
+  })
+
+  it('allows pull_request_target fork PR checkout when opted in', () => {
+    setContext('pull_request_target', forkPullRequestTargetPayload())
+    expect(() =>
+      assertSafePrCheckout({
+        qualifiedRepository: BASE_QUALIFIED_REPO,
+        ref: 'refs/pull/42/merge',
+        commit: '',
+        allowUnsafePrCheckout: true
+      })
+    ).not.toThrow()
+  })
+
+  it('refuses workflow_run fork PR head_commit.id checkout', () => {
+    setContext('workflow_run', forkWorkflowRunPayload())
+    expect(() =>
+      assertSafePrCheckout({
+        qualifiedRepository: BASE_QUALIFIED_REPO,
+        ref: '',
+        commit: WORKFLOW_RUN_HEAD_COMMIT_SHA,
+        allowUnsafePrCheckout: false
+      })
+    ).toThrow()
+  })
+
+  it('refuses workflow_run with pull_request_target underlying event', () => {
+    const payload = forkWorkflowRunPayload() as {
+      workflow_run: {event: string}
+    }
+    payload.workflow_run.event = 'pull_request_target'
+    setContext('workflow_run', payload)
+    expect(() =>
+      assertSafePrCheckout({
+        qualifiedRepository: BASE_QUALIFIED_REPO,
+        ref: '',
+        commit: WORKFLOW_RUN_HEAD_COMMIT_SHA,
+        allowUnsafePrCheckout: false
+      })
+    ).toThrow()
+  })
+
+  it('allows workflow_run same-repo PR (head_repository.id matches base)', () => {
+    const payload = forkWorkflowRunPayload() as {
+      workflow_run: {head_repository: {id: number}}
+    }
+    payload.workflow_run.head_repository.id = BASE_REPO_ID
+    setContext('workflow_run', payload)
+    expect(() =>
+      assertSafePrCheckout({
+        qualifiedRepository: BASE_QUALIFIED_REPO,
+        ref: '',
+        commit: WORKFLOW_RUN_HEAD_COMMIT_SHA,
+        allowUnsafePrCheckout: false
+      })
+    ).not.toThrow()
+  })
+})

action.yml

@@ -68,7 +68,19 @@ inputs:
       When the `ssh-key` input is not provided, SSH URLs beginning with `git@github.com:` are
       converted to HTTPS.
     default: false
+  set-safe-directory:
+    description: Add repository path as safe.directory for Git global config by running `git config --global --add safe.directory <path>`
+    default: true
+  allow-unsafe-pr-checkout:
+    description: >
+      Required to check out fork pull request code from a workflow triggered by
+      `pull_request_target` or `workflow_run`. These workflows run with the
+      base repository's GITHUB_TOKEN, secrets, default-branch cache scope, and
+      runner access; fetching and executing a fork's code in that trusted
+      context commonly leads to "pwn request" vulnerabilities. Set to `true`
+      only after reviewing the risks at https://gh.io/securely-using-pull_request_target.
+    default: false
 runs:
-  using: node16
+  using: node12
   main: dist/index.js
   post: dist/index.js

package.json

@@ -1,6 +1,6 @@
 {
   "name": "checkout",
-  "version": "2.0.2",
+  "version": "2.6.0",
   "description": "checkout action",
   "main": "lib/main.js",
   "scripts": {
@@ -28,10 +28,10 @@
   },
   "homepage": "https://github.com/actions/checkout#readme",
   "dependencies": {
-    "@actions/core": "^1.2.6",
+    "@actions/core": "^1.10.0",
     "@actions/exec": "^1.0.1",
     "@actions/github": "^2.2.0",
-    "@actions/io": "^1.0.1",
+    "@actions/io": "^1.1.2",
     "@actions/tool-cache": "^1.1.2",
     "uuid": "^3.3.3"
   },
@@ -39,11 +39,12 @@
     "@types/jest": "^27.0.2",
     "@types/node": "^12.7.12",
     "@types/uuid": "^3.4.6",
-    "@typescript-eslint/parser": "^5.1.0",
+    "@typescript-eslint/eslint-plugin": "^5.45.0",
+    "@typescript-eslint/parser": "^5.45.0",
     "@zeit/ncc": "^0.20.5",
     "eslint": "^7.32.0",
     "eslint-plugin-github": "^4.3.2",
-    "eslint-plugin-jest": "^25.2.2",
+    "eslint-plugin-jest": "^25.7.0",
     "jest": "^27.3.0",
     "jest-circus": "^27.3.0",
     "js-yaml": "^3.13.1",

src/git-auth-helper.ts

@@ -19,7 +19,7 @@ export interface IGitAuthHelper {
   configureAuth(): Promise<void>
   configureGlobalAuth(): Promise<void>
   configureSubmoduleAuth(): Promise<void>
-  configureTempGlobalConfig(repositoryPath?: string): Promise<string>
+  configureTempGlobalConfig(): Promise<string>
   removeAuth(): Promise<void>
   removeGlobalConfig(): Promise<void>
 }
@@ -81,7 +81,7 @@ class GitAuthHelper {
     await this.configureToken()
   }
 
-  async configureTempGlobalConfig(repositoryPath?: string): Promise<string> {
+  async configureTempGlobalConfig(): Promise<string> {
     // Already setup global config
     if (this.temporaryHomePath?.length > 0) {
       return path.join(this.temporaryHomePath, '.gitconfig')
@@ -121,21 +121,6 @@ class GitAuthHelper {
     )
     this.git.setEnvironmentVariable('HOME', this.temporaryHomePath)
 
-    // Setup the workspace as a safe directory, so if we pass this into a container job with a different user it doesn't fail
-    // Otherwise all git commands we run in a container fail
-    core.info(
-      `Adding working directory to the temporary git global config as a safe directory`
-    )
-    await this.git
-      .config(
-        'safe.directory',
-        repositoryPath ?? this.settings.repositoryPath,
-        true,
-        true
-      )
-      .catch(error => {
-        core.info(`Failed to initialize safe directory with error: ${error}`)
-      })
     return newGitConfigPath
   }
 
@@ -172,7 +157,8 @@ class GitAuthHelper {
       // 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
       const output = await this.git.submoduleForeach(
-        `git config --local '${this.tokenConfigKey}' '${this.tokenPlaceholderConfigValue}' && git config --local --show-origin --name-only --get-regexp remote.origin.url`,
+        // wrap the pipeline in quotes to make sure it's handled properly by submoduleForeach, rather than just the first part of the pipeline
+        `sh -c "git config --local '${this.tokenConfigKey}' '${this.tokenPlaceholderConfigValue}' && git config --local --show-origin --name-only --get-regexp remote.origin.url"`,
         this.settings.nestedSubmodules
       )
 
@@ -261,7 +247,7 @@ class GitAuthHelper {
     if (this.settings.sshKnownHosts) {
       knownHosts += `# Begin from input known hosts\n${this.settings.sshKnownHosts}\n# end from input known hosts\n`
     }
-    knownHosts += `# Begin implicitly added github.com\ngithub.com ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAq2A7hRGmdnm9tUDbO9IDSwBK6TbQa+PXYPCPy6rbTrTtw7PHkccKrpp0yVhp5HdEIcKr6pLlVDBfOLX9QUsyCOV0wzfjIJNlGEYsdlLJizHhbn2mUjvSAHQqZETYP81eFzLQNnPHt4EVVUh7VfDESU84KezmD5QlWpXLmvU31/yMf+Se8xhHTvKSCZIFImWwoG6mbUoWf9nzpIoaSjB+weqqUUmpaaasXVal72J+UX2B+2RPW3RcT0eOzQgqlJL3RKrTJvdsjE3JEAvGq3lGHSZXy28G3skua2SmVi/w4yCE6gbODqnTWlg7+wC604ydGXA8VJiS5ap43JXiUFFAaQ==\n# End implicitly added github.com\n`
+    knownHosts += `# Begin implicitly added github.com\ngithub.com ssh-rsa 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\n# End implicitly added github.com\n`
     this.sshKnownHostsPath = path.join(runnerTemp, `${uniqueId}_known_hosts`)
     stateHelper.setSshKnownHostsPath(this.sshKnownHostsPath)
     await fs.promises.writeFile(this.sshKnownHostsPath, knownHosts)
@@ -380,7 +366,8 @@ class GitAuthHelper {
 
     const pattern = regexpHelper.escape(configKey)
     await this.git.submoduleForeach(
-      `git config --local --name-only --get-regexp '${pattern}' && git config --local --unset-all '${configKey}' || :`,
+      // wrap the pipeline in quotes to make sure it's handled properly by submoduleForeach, rather than just the first part of the pipeline
+      `sh -c "git config --local --name-only --get-regexp '${pattern}' && git config --local --unset-all '${configKey}' || :"`,
       true
     )
   }

src/git-source-provider.ts

@@ -40,7 +40,24 @@ export async function getSource(settings: IGitSourceSettings): Promise<void> {
   try {
     if (git) {
       authHelper = gitAuthHelper.createAuthHelper(git, settings)
+      if (settings.setSafeDirectory) {
+        // Setup the repository path as a safe directory, so if we pass this into a container job with a different user it doesn't fail
+        // Otherwise all git commands we run in a container fail
         await authHelper.configureTempGlobalConfig()
+        core.info(
+          `Adding repository directory to the temporary git global config as a safe directory`
+        )
+
+        await git
+          .config('safe.directory', settings.repositoryPath, true, true)
+          .catch(error => {
+            core.info(
+              `Failed to initialize safe directory with error: ${error}`
+            )
+          })
+
+        stateHelper.setSafeDirectory()
+      }
     }
 
     // Prepare existing directory, otherwise recreate
@@ -249,7 +266,21 @@ export async function cleanup(repositoryPath: string): Promise<void> {
   // Remove auth
   const authHelper = gitAuthHelper.createAuthHelper(git)
   try {
-    await authHelper.configureTempGlobalConfig(repositoryPath)
+    if (stateHelper.PostSetSafeDirectory) {
+      // Setup the repository path as a safe directory, so if we pass this into a container job with a different user it doesn't fail
+      // Otherwise all git commands we run in a container fail
+      await authHelper.configureTempGlobalConfig()
+      core.info(
+        `Adding repository directory to the temporary git global config as a safe directory`
+      )
+
+      await git
+        .config('safe.directory', repositoryPath, true, true)
+        .catch(error => {
+          core.info(`Failed to initialize safe directory with error: ${error}`)
+        })
+    }
+
     await authHelper.removeAuth()
   } finally {
     await authHelper.removeGlobalConfig()

src/git-source-settings.ts

@@ -78,4 +78,15 @@ export interface IGitSourceSettings {
    * Organization ID for the currently running workflow (used for auth settings)
    */
   workflowOrganizationId: number | undefined
+
+  /**
+   * Indicates whether to add repositoryPath as safe.directory in git global config
+   */
+  setSafeDirectory: boolean
+
+  /**
+   * Opt-in to allow checking out fork pull request code from a workflow
+   * triggered by pull_request_target or workflow_run.
+   */
+  allowUnsafePrCheckout: boolean
 }

src/input-helper.ts

@@ -2,6 +2,7 @@ import * as core from '@actions/core'
 import * as fsHelper from './fs-helper'
 import * as github from '@actions/github'
 import * as path from 'path'
+import * as unsafePrCheckoutHelper from './unsafe-pr-checkout-helper'
 import * as workflowContextHelper from './workflow-context-helper'
 import {IGitSourceSettings} from './git-source-settings'
 
@@ -58,6 +59,23 @@ export async function getInputs(): Promise<IGitSourceSettings> {
 
   // Source branch, source version
   result.ref = core.getInput('ref')
+  // core.getInput()'s default trim strips a range of Unicode characters such as a
+  // leading BOM (U+FEFF) or NBSP (U+00A0). Those are valid in a git ref name, so
+  // a fork branch named "<BOM>" + 40 hex chars would trim down to a bare SHA and
+  // be silently reclassified as a commit, bypassing the unsafe fork PR checkout
+  // guard.
+  //
+  // The trim below strips only the ASCII whitespace characters which are all forbidden
+  // in a git branch name.
+  //   \t  U+0009  horizontal tab   - ASCII control, forbidden in ref names
+  //   \n  U+000A  line feed        - ASCII control, forbidden in ref names
+  //   \v  U+000B  vertical tab     - ASCII control, forbidden in ref names
+  //   \f  U+000C  form feed        - ASCII control, forbidden in ref names
+  //   \r  U+000D  carriage return  - ASCII control, forbidden in ref names
+  //   ' ' U+0020  space            - forbidden in ref names
+  const asciiTrimmedRef = core
+    .getInput('ref', {trimWhitespace: false})
+    .replace(/^[\t\n\v\f\r ]+|[\t\n\v\f\r ]+$/g, '')
   if (!result.ref) {
     if (isWorkflowRepository) {
       result.ref = github.context.ref
@@ -71,8 +89,8 @@ export async function getInputs(): Promise<IGitSourceSettings> {
     }
   }
   // SHA?
-  else if (result.ref.match(/^[0-9a-fA-F]{40}$/)) {
+  else if (asciiTrimmedRef.match(/^[0-9a-fA-F]{40}$/)) {
-    result.commit = result.ref
+    result.commit = asciiTrimmedRef
     result.ref = ''
   }
   core.debug(`ref = '${result.ref}'`)
@@ -122,5 +140,29 @@ export async function getInputs(): Promise<IGitSourceSettings> {
   // Workflow organization ID
   result.workflowOrganizationId = await workflowContextHelper.getOrganizationId()
 
+  // Set safe.directory in git global config.
+  result.setSafeDirectory =
+    (core.getInput('set-safe-directory') || 'true').toUpperCase() === 'TRUE'
+
+  // Allow unsafe PR checkout (opt-in for pull_request_target / workflow_run fork PRs)
+  result.allowUnsafePrCheckout =
+    (core.getInput('allow-unsafe-pr-checkout') || 'false').toUpperCase() ===
+    'TRUE'
+  core.debug(`allow unsafe PR checkout = ${result.allowUnsafePrCheckout}`)
+
+  // The default self-checkout (this repository with no explicit ref) always
+  // resolves to the trusted ref/commit GitHub set for the triggering event, so
+  // the fork-checkout guard only needs to run when the caller customized the
+  // repository or ref.
+  const isDefaultCheckout = isWorkflowRepository && !core.getInput('ref')
+  if (!isDefaultCheckout) {
+    unsafePrCheckoutHelper.assertSafePrCheckout({
+      qualifiedRepository,
+      ref: result.ref,
+      commit: result.commit,
+      allowUnsafePrCheckout: result.allowUnsafePrCheckout
+    })
+  }
+
   return result
 }

src/misc/generate-docs.ts

@@ -120,7 +120,7 @@ function updateUsage(
 }
 
 updateUsage(
-  'actions/checkout@v3',
+  'actions/checkout@v2',
   path.join(__dirname, '..', '..', 'action.yml'),
   path.join(__dirname, '..', '..', 'README.md')
 )

src/ref-helper.ts

@@ -259,7 +259,7 @@ export async function checkCommitInfo(
   }
 }
 
-function fromPayload(path: string): any {
+export function fromPayload(path: string): any {
   return select(github.context.payload, path)
 }
 

src/state-helper.ts

@@ -1,58 +1,60 @@
-import * as coreCommand from '@actions/core/lib/command'
+import * as core from '@actions/core'
 
 /**
  * Indicates whether the POST action is running
  */
-export const IsPost = !!process.env['STATE_isPost']
+export const IsPost = !!core.getState('isPost')
 
 /**
  * The repository path for the POST action. The value is empty during the MAIN action.
  */
-export const RepositoryPath =
+export const RepositoryPath = core.getState('repositoryPath')
-  (process.env['STATE_repositoryPath'] as string) || ''
+
+/**
+ * The set-safe-directory for the POST action. The value is set if input: 'safe-directory' is set during the MAIN action.
+ */
+export const PostSetSafeDirectory = core.getState('setSafeDirectory') === 'true'
 
 /**
  * The SSH key path for the POST action. The value is empty during the MAIN action.
  */
-export const SshKeyPath = (process.env['STATE_sshKeyPath'] as string) || ''
+export const SshKeyPath = core.getState('sshKeyPath')
 
 /**
  * The SSH known hosts path for the POST action. The value is empty during the MAIN action.
  */
-export const SshKnownHostsPath =
+export const SshKnownHostsPath = core.getState('sshKnownHostsPath')
-  (process.env['STATE_sshKnownHostsPath'] as string) || ''
 
 /**
  * Save the repository path so the POST action can retrieve the value.
  */
 export function setRepositoryPath(repositoryPath: string) {
-  coreCommand.issueCommand(
+  core.saveState('repositoryPath', repositoryPath)
-    'save-state',
-    {name: 'repositoryPath'},
-    repositoryPath
-  )
 }
 
 /**
  * Save the SSH key path so the POST action can retrieve the value.
  */
 export function setSshKeyPath(sshKeyPath: string) {
-  coreCommand.issueCommand('save-state', {name: 'sshKeyPath'}, sshKeyPath)
+  core.saveState('sshKeyPath', sshKeyPath)
 }
 
 /**
  * Save the SSH known hosts path so the POST action can retrieve the value.
  */
 export function setSshKnownHostsPath(sshKnownHostsPath: string) {
-  coreCommand.issueCommand(
+  core.saveState('sshKnownHostsPath', sshKnownHostsPath)
-    'save-state',
+}
-    {name: 'sshKnownHostsPath'},
+
-    sshKnownHostsPath
+/**
-  )
+ * Save the sef-safe-directory input so the POST action can retrieve the value.
+ */
+export function setSafeDirectory() {
+  core.saveState('setSafeDirectory', 'true')
 }
 
 // Publish a variable so that when the POST action runs, it can determine it should run the cleanup logic.
 // This is necessary since we don't have a separate entry point.
 if (!IsPost) {
-  coreCommand.issueCommand('save-state', {name: 'isPost'}, 'true')
+  core.saveState('isPost', 'true')
 }

src/unsafe-pr-checkout-helper.ts

@@ -0,0 +1,88 @@
+import * as github from '@actions/github'
+import {fromPayload} from './ref-helper'
+
+const PR_REF_PATTERN = /^refs\/pull\/[0-9]+\/(?:head|merge)$/
+
+export interface IUnsafePrCheckoutInput {
+  qualifiedRepository: string
+  ref: string
+  commit: string | undefined
+  allowUnsafePrCheckout: boolean
+}
+
+export function assertSafePrCheckout(input: IUnsafePrCheckoutInput): void {
+  if (input.allowUnsafePrCheckout) {
+    return
+  }
+
+  const eventName = github.context.eventName
+  if (eventName !== 'pull_request_target' && eventName !== 'workflow_run') {
+    return
+  }
+
+  const baseRepoId = fromPayload('repository.id')
+  if (typeof baseRepoId !== 'number') {
+    return
+  }
+
+  let prHeadRepoId: unknown
+  let prHeadRepoFullName: unknown
+  const prShas: string[] = []
+
+  if (eventName === 'pull_request_target') {
+    prHeadRepoId = fromPayload('pull_request.head.repo.id')
+    prHeadRepoFullName = fromPayload('pull_request.head.repo.full_name')
+    pushIfSha(prShas, fromPayload('pull_request.head.sha'))
+    pushIfSha(prShas, fromPayload('pull_request.merge_commit_sha'))
+  } else {
+    const wrEvent = fromPayload('workflow_run.event')
+    if (typeof wrEvent !== 'string' || !wrEvent.startsWith('pull_request')) {
+      return
+    }
+    prHeadRepoId = fromPayload('workflow_run.head_repository.id')
+    prHeadRepoFullName = fromPayload('workflow_run.head_repository.full_name')
+    pushIfSha(prShas, fromPayload('workflow_run.head_commit.id'))
+    // For `pull_request_target`-triggered workflow_run, `head_sha` is the base
+    // default branch SHA (not the PR head)
+    if (wrEvent !== 'pull_request_target') {
+      pushIfSha(prShas, fromPayload('workflow_run.head_sha'))
+    }
+  }
+
+  // (A) Fork PR?
+  if (typeof prHeadRepoId !== 'number' || prHeadRepoId === baseRepoId) {
+    return
+  }
+
+  // (B) We cannot check for all fork PR refs so check to see
+  // if the resolved input points to the fork PR sha we have in the payload
+  const repositoryMatchesPrHead =
+    typeof prHeadRepoFullName === 'string' &&
+    input.qualifiedRepository.toLowerCase() === prHeadRepoFullName.toLowerCase()
+  const refMatchesPullPattern = PR_REF_PATTERN.test(input.ref)
+  const commitMatchesPrHeadSha =
+    !!input.commit && prShas.includes(input.commit.toLowerCase())
+
+  if (
+    !repositoryMatchesPrHead &&
+    !refMatchesPullPattern &&
+    !commitMatchesPrHeadSha
+  ) {
+    return
+  }
+
+  throw new Error(
+    `Refusing to check out fork pull request code from a '${eventName}' workflow. ` +
+      `This workflow runs with the base repository's GITHUB_TOKEN, secrets, default-branch ` +
+      `cache scope, and runner access. Fetching and executing a fork's code in that trusted ` +
+      `context commonly leads to "pwn request" vulnerabilities. To opt in, review the risks ` +
+      `at https://gh.io/securely-using-pull_request_target and set 'allow-unsafe-pr-checkout: true' ` +
+      `on the actions/checkout step.`
+  )
+}
+
+function pushIfSha(target: string[], value: unknown): void {
+  if (typeof value === 'string' && value.length > 0) {
+    target.push(value.toLowerCase())
+  }
+}