Merge pull request #4311 from sashashura/patch-1

GitHub Workflows security hardening
This PR adds explicit permissions section to workflows. This is a security best practice because by default workflows run with extended set of permissions (except from on: pull_request from external forks). By specifying any permission explicitly all others are set to none. By using the principle of least privilege the damage a compromised workflow can do (because of an injection or compromised third party tool or action) is restricted.
It is recommended to have most strict permissions on the top level and grant write permissions on job level case by case.

.github/workflows/bumpversion.yml

@@ -3,8 +3,12 @@ on:
   push:
     branches:
       - master
+permissions: {}
 jobs:
   build:
+    permissions:
+      contents: write # to create a tag (mathieudutour/github-tag-action)
+
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v2

.github/workflows/docs.yml

@@ -9,6 +9,8 @@ on:
     branches:
       - master
 
+permissions:
+  contents: read
 jobs:
   check-changes:
     name: Check for changes to documentation
@@ -25,6 +27,9 @@ jobs:
         with:
           files: doc
   build-and-deploy:
+    permissions:
+      contents: write  #  for peaceiris/actions-gh-pages to push
+      pull-requests: write  #  to comment on pull requests
     needs: check-changes
     if: needs.check-changes.outputs.any_changed == 'true'
     name: Build and deploy documentation
@@ -93,6 +98,8 @@ jobs:
           user_name: 'github-actions[bot]'
           user_email: 'github-actions[bot]@users.noreply.github.com'
   cleanup:
+    permissions:
+      contents: write  #  for git push
     needs: build-and-deploy
     name: Cleanup branch previews
     runs-on: ubuntu-latest

.github/workflows/testing.yml

@@ -13,6 +13,9 @@ concurrency:
   group: ${{ github.ref }}
   cancel-in-progress: true
 
+permissions:
+  contents: read # to fetch code (actions/checkout)
+
 jobs:
   pre-commit:
     runs-on: ubuntu-latest