rebuild

* block checking out fork pr for some events

* address copilot and reviewer feedback

* run prettier formatting

* build

* update urls

* update readme

* update description and url again

* edit url one more time

.github/workflows/check-dist.yml

@@ -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/test.yml

@@ -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:

.licenses/npm/@actions/core.dep.yml

@@ -1,9 +1,9 @@
 ---
 name: "@actions/core"
-version: 1.2.6
+version: 1.10.0
 type: npm
-summary: 
-homepage: 
+summary: Actions core lib
+homepage: https://github.com/actions/toolkit/tree/main/packages/core
 license: mit
 licenses:
 - sources: LICENSE.md

.licenses/npm/@actions/http-client-2.0.1.dep.yml

@@ -0,0 +1,32 @@
+---
+name: "@actions/http-client"
+version: 2.0.1
+type: npm
+summary: Actions Http Client
+homepage: https://github.com/actions/toolkit/tree/main/packages/http-client
+license: mit
+licenses:
+- sources: LICENSE
+  text: |
+    Actions Http Client for Node.js
+
+    Copyright (c) GitHub, Inc.
+
+    All rights reserved.
+
+    MIT License
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
+    associated documentation files (the "Software"), to deal in the Software without restriction,
+    including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense,
+    and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so,
+    subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED *AS IS*, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT
+    LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+    NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+    WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+    SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+notices: []

.licenses/npm/@actions/io.dep.yml

@@ -1,13 +1,15 @@
 ---
 name: "@actions/io"
-version: 1.0.1
+version: 1.1.2
 type: npm
 summary: Actions io lib
-homepage: https://github.com/actions/toolkit/tree/master/packages/io
+homepage: https://github.com/actions/toolkit/tree/main/packages/io
 license: mit
 licenses:
 - sources: LICENSE.md
   text: |-
+    The MIT License (MIT)
+
     Copyright 2019 GitHub
 
     Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

.licenses/npm/node-fetch.dep.yml

@@ -1,6 +1,6 @@
 ---
 name: node-fetch
-version: 2.6.5
+version: 2.6.7
 type: npm
 summary: A light-weight module that brings window.fetch to node.js
 homepage: https://github.com/bitinn/node-fetch

.licenses/npm/qs.dep.yml

@@ -1,6 +1,6 @@
 ---
 name: qs
-version: 6.10.1
+version: 6.11.0
 type: npm
 summary: A querystring parser that supports nesting and arrays, with a depth limit
 homepage: https://github.com/ljharb/qs

.licenses/npm/uuid-3.3.3.dep.yml

@@ -3,7 +3,7 @@ name: uuid
 version: 3.3.3
 type: npm
 summary: RFC4122 (v1, v4, and v5) UUIDs
-homepage: https://github.com/kelektiv/node-uuid#readme
+homepage: 
 license: mit
 licenses:
 - sources: LICENSE.md

.licenses/npm/uuid-8.3.2.dep.yml

@@ -0,0 +1,20 @@
+---
+name: uuid
+version: 8.3.2
+type: npm
+summary: RFC4122 (v1, v4, and v5) UUIDs
+homepage: 
+license: mit
+licenses:
+- sources: LICENSE.md
+  text: |
+    The MIT License (MIT)
+
+    Copyright (c) 2010-2020 Robert Kieffer and other contributors
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+notices: []

CHANGELOG.md

@@ -1,5 +1,8 @@
 # Changelog
 
+## v2.5.0
+- [Bump @actions/core to v1.10.0](https://github.com/actions/checkout/pull/962)
+
 ## v2.4.2
 - [Add input `set-safe-directory`](https://github.com/actions/checkout/pull/776)
 

README.md

@@ -110,6 +110,15 @@ Refer [here](https://github.com/actions/checkout/blob/v1/README.md) for previous
     # 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 -->
 

__test__/git-auth-helper.test.ts

@@ -778,7 +778,8 @@ async function setup(testName: string): Promise<void> {
     sshKnownHosts: '',
     sshStrict: true,
     workflowOrganizationId: 123456,
-    setSafeDirectory: true
+    setSafeDirectory: true,
+    allowUnsafePrCheckout: false
   }
 }
 

__test__/input-helper.test.ts

@@ -86,6 +86,7 @@ describe('input-helper tests', () => {
     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 () => {

__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

@@ -71,6 +71,15 @@ inputs:
   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: node12
   main: 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

@@ -157,7 +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
       )
 
@@ -246,7 +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)
@@ -365,7 +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-settings.ts

@@ -83,4 +83,10 @@ export interface IGitSourceSettings {
    * 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'
 
@@ -125,5 +126,19 @@ export async function getInputs(): Promise<IGitSourceSettings> {
   // 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}`)
+
+  unsafePrCheckoutHelper.assertSafePrCheckout({
+    qualifiedRepository,
+    ref: result.ref,
+    commit: result.commit,
+    allowUnsafePrCheckout: result.allowUnsafePrCheckout
+  })
+
   return result
 }

src/misc/licensed-check.sh

@@ -5,4 +5,4 @@ set -e
 src/misc/licensed-download.sh
 
 echo 'Running: licensed cached'
-_temp/licensed-3.3.1/licensed status
+_temp/licensed-3.6.0/licensed status

src/misc/licensed-download.sh

@@ -2,23 +2,23 @@
 
 set -e
 
-if [ ! -f _temp/licensed-3.3.1.done ]; then
+if [ ! -f _temp/licensed-3.6.0.done ]; then
   echo 'Clearing temp'
-  rm -rf _temp/licensed-3.3.1 || true
+  rm -rf _temp/licensed-3.6.0 || true
 
   echo 'Downloading licensed'
-  mkdir -p _temp/licensed-3.3.1
-  pushd _temp/licensed-3.3.1
+  mkdir -p _temp/licensed-3.6.0
+  pushd _temp/licensed-3.6.0
   if [[ "$OSTYPE" == "darwin"* ]]; then
-    curl -Lfs -o licensed.tar.gz https://github.com/github/licensed/releases/download/3.3.1/licensed-3.3.1-darwin-x64.tar.gz
+    curl -Lfs -o licensed.tar.gz https://github.com/github/licensed/releases/download/3.6.0/licensed-3.6.0-darwin-x64.tar.gz
   else
-    curl -Lfs -o licensed.tar.gz https://github.com/github/licensed/releases/download/3.3.1/licensed-3.3.1-linux-x64.tar.gz
+    curl -Lfs -o licensed.tar.gz https://github.com/github/licensed/releases/download/3.6.0/licensed-3.6.0-linux-x64.tar.gz
   fi
 
   echo 'Extracting licenesed'
   tar -xzf licensed.tar.gz
   popd
-  touch _temp/licensed-3.3.1.done
+  touch _temp/licensed-3.6.0.done
 else
   echo 'Licensed already downloaded'
 fi

src/misc/licensed-generate.sh

@@ -5,4 +5,4 @@ set -e
 src/misc/licensed-download.sh
 
 echo 'Running: licensed cached'
-_temp/licensed-3.3.1/licensed cache
+_temp/licensed-3.6.0/licensed cache

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

@@ -1,71 +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 =
-  (process.env['STATE_repositoryPath'] as string) || ''
+export const RepositoryPath = core.getState('repositoryPath')
 
 /**
  * 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 =
-  (process.env['STATE_setSafeDirectory'] as string) === 'true'
+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 =
-  (process.env['STATE_sshKnownHostsPath'] as string) || ''
+export const SshKnownHostsPath = core.getState('sshKnownHostsPath')
 
 /**
  * Save the repository path so the POST action can retrieve the value.
  */
 export function setRepositoryPath(repositoryPath: string) {
-  coreCommand.issueCommand(
-    'save-state',
-    {name: 'repositoryPath'},
-    repositoryPath
-  )
+  core.saveState('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(
-    'save-state',
-    {name: 'sshKnownHostsPath'},
-    sshKnownHostsPath
-  )
+  core.saveState('sshKnownHostsPath', sshKnownHostsPath)
 }
 
 /**
  * Save the sef-safe-directory input so the POST action can retrieve the value.
  */
 export function setSafeDirectory() {
-  coreCommand.issueCommand('save-state', {name: 'setSafeDirectory'}, 'true')
+  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())
+  }
+}