Add policy document for using GitHub actions in workflows

.spellcheck-en-custom.txt

@@ -20,14 +20,18 @@ cuBLAS
 CUDA
 dataset
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+Dependabot
 dev
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+exfiltrate
+exfiltrating
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+formedness
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@@ -53,6 +57,7 @@ llms
 LLVM
 lora
 md
+Markdownlint
 Mergify
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 mimimum
@@ -89,6 +94,7 @@ RX
 safetensors
 Salawu
 SDG
+Sigstore
 sexualized
 SHA
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@@ -101,7 +107,6 @@ tatsu
 TBD
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-th
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docs/github-actions-providers.md

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+# GitHub Actions Providers
+
+## Approved Providers
+
+* `actions/*@*` - GitHub created actions
+* `DavidAnson/markdownlint-cli2-action@*` - Markdownlint-cli2 action
+* `docker/*@*` - Docker actions
+* `pypa/*@*` - Python Packaging actions
+* `rojopolis/spellcheck-github-actions@*` - Spellcheck action
+* `sigstore/gh-action-sigstore-python@*` - Sigstore Python action
+* `step-security/harden-runner@*` - Harden Runner action
+
+## Denied Providers
+
+There are currently no denied providers.

docs/github-actions-use-policy.md

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+# GitHub Actions Use Policy for InstructLab
+
+This document describes the use policy for GitHub Actions (actions) in workflows for all repositories in the [InstructLab](https://github.com/instructlab) organization.
+
+## Background
+
+GitHub Actions are an important tool for CI/CD use within the repositories of the InstructLab project.
+One of the main values is to verify the quality of pull requests for things like tests passing, spelling checks, well-formedness of files, etc.
+Repositories may also use actions to build and publish releases for the project.
+
+Since actions play a critical role in the project, care must be taken in how they are used due to their place in the security of the software supply chain of the project.
+
+## Dependabot
+
+Each repository using GitHub Actions must configure Dependabot to manage the action dependencies.
+The repository must contain a `.github/dependabot.yml` file with the following minimum configuration:
+
+```yaml
+version: 2
+updates:
+  # Maintain dependencies for GitHub Actions
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "daily"
+```
+
+Repository maintainers must review and respond to all pull requests submitted by Dependabot in a timely manner.
+
+## SHAs instead of tags
+
+GitHub Actions must be referenced using SHA values for a specific commit.
+Use of other reference types such as tag or branch names is not permitted.
+
+```yaml
+- name: Git Checkout
+  uses: actions/checkout@0ad4b8fadaa221de15dcec353f45205ec38ea70b # v4.1.4
+```
+
+instead of
+
+```yaml
+- name: Git Checkout
+  uses: actions/checkout@v4
+```
+
+The use of SHAs can avoid security issues if the tag or branch of the action is moved to a malicious commit.
+We also gain build repeatability for future builds by referring to a precise revision of the action.
+
+Since we use Dependabot to manage our action dependencies, Dependabot will handle the chore of using the proper SHA values in the submitted pull requests when action dependencies are updated.
+
+## Trusted Providers of GitHub Actions
+
+There are many GitHub Actions available in GitHub.
+Not all can be necessarily trusted.
+The InstructLab project must maintain [a list of allowed providers and a list of denied providers](github-actions-providers.md).
+
+Allowed providers will include all GitHub created actions (`actions/*`) as well as other official actions such as Python Packaging actions (`pypa/*`).
+
+The InstructLab organization's Settings->Actions->General must be configured to allow select actions including actions created by GitHub along with the allowed providers.
+
+Adding actions to the allowed providers or denied providers lists will require approval by the organization maintainers along with updating the organization's settings. This can be done by submitting a Pull Request to modify [`github-actions-providers.md`](github-actions-providers.md).
+
+## Harden the GitHub Action runner
+
+To further increase security, the first step of each job in a workflow must be the [`step-security/harden-runner`](https://github.com/step-security/harden-runner) action.
+This action hardens the action runner by implementing network egress control and some infrastructure security.
+
+```yaml
+- name: "Harden Runner"
+  uses: step-security/harden-runner@a4aa98b93cab29d9b1101a6143fb8bce00e2eac4 # v2.7.1
+  with:
+    egress-policy: audit # TODO: change to 'egress-policy: block' after couple of runs
+```
+
+Each execution of the workflow job will produce a report showing endpoints accessed by the job and possible source file overwrites.
+The report will also suggest modifications to the harden-runner action's configuration to further increase security.
+
+```yaml
+- name: "Harden Runner"
+  uses: step-security/harden-runner@a4aa98b93cab29d9b1101a6143fb8bce00e2eac4 # v2.7.1
+  with:
+    disable-sudo: true
+    egress-policy: block
+    allowed-endpoints: >
+      github.com:443
+```
+
+Hardening the action runner like this can prevent malicious or misbehaving actions or the misuse of actions from exfiltrating secrets.
+The article [Harden-Runner Defends Against Arbitrary Command Execution in `tj-actions/changed-files` GitHub Action](https://www.stepsecurity.io/blog/defend-against-arbitrary-command-execution-in-tj-actions-changed-files) shows how the misuse of an action could allow an attacker with a well-crafted pull request to exfiltrate secrets.