scan-secrets.yml

---

name: Scan for secret leaks and changes

on:
  # Block PR modification of workflow
  pull_request_target:
  push:
  workflow_dispatch:

# N/B: Default write-all permission for pull_request_target
permissions: read-all

env:
  # How far back in history to go when scanning a branch/tag
  # This is most significant when scanning vs new release-branches
  # with commit IDs that may differ from those encoded in the
  # .gitleaks/baseline.json data (which always comes from
  # the default branch).
  # TODO: Is there any way to not hard-code this?
  # N/B: This value is reused by Cirrus-CI, see contrib/cirrus/prebuild.sh
  brdepth: 50

  # GitLeaks container image to use.
  # N/B: Updating this is hard to test, esp. care must be exercised re: new leak-ignore behaviors
  # (example ref: 'Check for inline scan overrides' step below).  Also b/c this workflow is not
  # intended to be used with the 'pull_request' trigger - as doing so defeats gitleaks scan
  # result trustworthiness.
  # N/B: This value is reused by Cirrus-CI, see contrib/cirrus/prebuild.sh
  glfqin: ghcr.io/gitleaks/gitleaks@sha256:e5f6d1a62786affd1abd882ecc73e9353ce78adea1650711f6e351767723712d  # v8.18.0

  # General arguments to pass for all execution contexts
  # Ref: https://github.com/gitleaks/gitleaks#usage
  # N/B: This value is reused by Cirrus-CI, see contrib/cirrus/prebuild.sh
  glargs: >-
    --exit-code=1
    --no-banner
    --verbose
    --log-level=debug
    --source=/subject
    --config=/default/.gitleaks.toml
    --report-path=/report/gitleaks-report.json
    --baseline-path=/default/.gitleaks/baseline.json

  # Where to send notification e-mail
  RCPTCSV: podman-monitor@lists.podman.io

jobs:
  scan-secrets:
    runs-on: ubuntu-latest
    env:
      # Reduce duplication & command-line length
      gitlogcmd: "git -C ${{ github.workspace }}/_subject log -p -U0"
    steps:
      - name: Define git log command and options for re-use
        id: gitlog
        shell: bash
        run: |
          set -exuo pipefail
          if [[ "${{ github.base_ref }}" == "" ]]; then  # It's a branch/tag
            echo "range=-${{ env.brdepth }}" >> $GITHUB_OUTPUT
          else  # It's a PR
            echo "range=${{ github.event.pull_request.head.sha }}~${{ github.event.pull_request.commits }}..HEAD" >> $GITHUB_OUTPUT
          fi

      # On a large repo, there's no need to check out the entire thing.  For PRs
      # the depth can be limited to one-greater than the number of PR commits.
      # Unfortunately, GHA is incapable of performing simple math in-line.
      - name: Do some simple math for PR clone depth
        if: github.base_ref != ''
        id: one_more_commit
        shell: bash
        run: |
          echo "depth=$((${{ github.event.pull_request.commits }} + 1))" >> $GITHUB_OUTPUT

      - name: Show important context details
        shell: bash
        run: |
          set -euo pipefail
          echo "The workspace path is '${{ github.workspace }}'"
          echo "The github.base_ref value is '${{ github.base_ref }}'"
          echo "The branch scan depth value is '${{ env.brdepth }}'"
          echo "The PR clone depth value is '${{ steps.one_more_commit.outputs.depth }}'"
          echo "The gitlogcmd value is '${{ env.gitlogcmd }}'"
          echo "The gitlog range value is '${{ steps.gitlog.outputs.range }}'"
          echo "The GitLeaks container FQIN is '${{ env.glfqin }}'"
          echo "::group::The trigger event JSON"
          jq --color-output --indent 2 --sort-keys . $GITHUB_EVENT_PATH
          echo "::endgroup::"

      # N/B: Use "_" prefixed paths to (somewhat) guard against clashes.  GHA has some
      # non-POLA behaviors WRT `${{ github.workspace }}` + checkout action.
      - name: Checkout PR
        if: github.base_ref != ''
        uses: actions/checkout@v4
        with:
          persist-credentials: false
          path: _subject
          ref: ${{ github.event.pull_request.head.sha }}
          fetch-depth: ${{ steps.one_more_commit.outputs.depth }}

      - name: Checkout Branch/Tag
        if: github.base_ref == ''
        uses: actions/checkout@v4
        with:
          persist-credentials: false
          path: _subject
          fetch-depth: ${{ env.brdepth }}

      # Trusted source of gitleaks config.
      - name: Checkout default branch
        uses: actions/checkout@v4
        with:
          persist-credentials: false
          ref: ${{ github.event.repository.default_branch }}
          path: _default
          fetch-depth: 1

      - name: Create report directory
        shell: bash
        run: |
          set -exuo pipefail
          mkdir ${{ github.workspace }}/_report
          touch ${{ github.workspace }}/_report/gitleaks-report.json

      # A force-push to a PR can obscure Cirrus-CI logs, but not GHA logs
      - name: Show content being scanned
        shell: bash
        run: |
          set -exuo pipefail
          ${{ env.gitlogcmd }} ${{ steps.gitlog.outputs.range }}

      # Unfortunately gitleaks provides several in-built ways to
      # completely bypass an alert within PR-level commits.  Assume
      # it's not possible to detect these with gitleaks-config rules.
      - name: Check for inline scan overrides
        if: github.base_ref != ''  # A PR
        shell: bash
        env:
          # Workaround erronously detecting the string in this file
          _rx1: "gitleaks"
          _rx2: ":"
          _rx3: "allow"
        run: |
          set -euo pipefail
          verboten_rx="${_rx1}${_rx2}${_rx3}"
          verboten=$(set -x ; ${{ env.gitlogcmd }} "-G$verboten_rx" ${{ steps.gitlog.outputs.range }})
          if [[ -n "$verboten" ]]; then
            printf '::error::%s' 'Found comment(s) utilizing detection override(s) (see job log for details)'
            # Hack: Grep will never colorize an end of a line match
            echo "$verboten" | grep --color=always -E "($verboten_rx)|$"
            exit 1
          fi

          if [[ -r "${{ github.workspace }}/_subject/.gitleaksignore" ]]; then
            printf '::error::%s' 'Detected a .gitleaksignore file from untrusted source.'
            exit 1
          fi

      - name: Scan for secrets
        shell: bash
        # gitleaks entrypoint runs as gitleaks user (UID/GID 1000)
        run: |
          set -exuo pipefail
          # TODO: Workaround podman < v4.3.0 support for `--userns=keep-id:uid=1000,gid=1000`.
          declare -a workaround_args
          workaround_args=(\
            --user 1000:1000
            --uidmap 0:1:1000
            --uidmap 1000:0:1
            --uidmap 1001:1001:64536
            --gidmap 0:1:1000
            --gidmap 1000:0:1
            --gidmap 1001:1001:64536
          )
          # Careful: Changes need coordination with contrib/cirrus/prebuild.sh
          podman run --rm \
            --security-opt=label=disable \
            "${workaround_args[@]}" \
            -v ${{ github.workspace }}/_default:/default:ro \
            -v ${{ github.workspace }}/_subject:/subject:ro \
            -v ${{ github.workspace }}/_report:/report:rw \
            $glfqin \
            detect $glargs --log-opts=${{ steps.gitlog.outputs.range }}

      - name: Collect scan report artifact
        if: ${{ !cancelled() }}
        uses: actions/upload-artifact@v3
        with:
          name: gitleaks-report
          path: ${{ github.workspace }}/_report/gitleaks-report.json

      # Nobody monitors the actions-tab for failures, and may not see this
      # fail on push to a nefarious PR.  Send an e-mail alert to unmask
      # this activity or some other general job failure.
      - if: failure() && !contains(github.event.pull_request.labels.*.name,'BypassLeakNotification')
        name: Send leak detection notification e-mail
        uses: dawidd6/action-send-mail@v3.9.0
        with:
          server_address: ${{secrets.ACTION_MAIL_SERVER}}
          server_port: 465
          username: ${{secrets.ACTION_MAIL_USERNAME}}
          password: ${{secrets.ACTION_MAIL_PASSWORD}}
          subject: Addition|Change|Use of sensitive ${{github.repository}}-CI value
          to: ${{env.RCPTCSV}}
          from: ${{secrets.ACTION_MAIL_SENDER}}
          body: "Please investigate: https://github.com/${{github.repository}}/actions/runs/${{github.run_id}}"