github actions: Introduce kernel-build-and-test-multiarch-trigger.yml

.github/workflows/kernel-build-and-test-multiarch-trigger.yml

@@ -0,0 +1,137 @@
+name: Trigger Automated kernel build and test (multi-arch)
+
+on:
+  workflow_call:
+    inputs:
+      architectures:
+        description: 'Comma-separated architectures to build (x86_64, aarch64)'
+        required: false
+        type: string
+        default: 'x86_64,aarch64'
+      skip_kabi:
+        description: 'Skip kABI compatibility check'
+        required: false
+        type: boolean
+        default: false
+
+permissions:
+  contents: read
+  actions: read
+  packages: read
+  # No pull-requests: write needed - we don't comment here
+
+jobs:
+  trigger-kernelCI:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Validate and sanitize inputs
+        id: validate_inputs
+        env:
+          BASE_REF: ${{ github.base_ref }}
+          HEAD_REF: ${{ github.head_ref }}
+          PR_NUMBER: ${{ github.event.pull_request.number }}
+          PR_COMMITS: ${{ github.event.pull_request.commits }}
+        run: |
+          # Validate base branch name (alphanumeric, dots, slashes, dashes, underscores, curly braces)
+          # Note: hyphen must be at end of character class or escaped to be literal
+          if ! [[ "$BASE_REF" =~ ^[a-zA-Z0-9/_.{}-]+$ ]]; then
+            echo "❌ Invalid base branch name: $BASE_REF"
+            exit 1
+          fi
+
+          # Validate head branch name
+          if ! [[ "$HEAD_REF" =~ ^[a-zA-Z0-9/_.{}-]+$ ]]; then
+            echo "❌ Invalid head branch name: $HEAD_REF"
+            exit 1
+          fi
+
+          # Validate length (prevent resource exhaustion)
+          if [ ${#BASE_REF} -gt 255 ]; then
+            echo "❌ Base branch name too long"
+            exit 1
+          fi
+
+          if [ ${#HEAD_REF} -gt 255 ]; then
+            echo "❌ Head branch name too long"
+            exit 1
+          fi
+
+          # Validate PR number is numeric
+          if ! [[ "$PR_NUMBER" =~ ^[0-9]+$ ]]; then
+            echo "❌ Invalid PR number: $PR_NUMBER"
+            exit 1
+          fi
+
+          # Validate commits count is numeric
+          if ! [[ "$PR_COMMITS" =~ ^[0-9]+$ ]]; then
+            echo "❌ Invalid commits count: $PR_COMMITS"
+            exit 1
+          fi
+
+          # Pass validated values to environment
+          echo "BASE_REF=$BASE_REF" >> "$GITHUB_ENV"
+          echo "HEAD_REF=$HEAD_REF" >> "$GITHUB_ENV"
+          echo "PR_NUMBER=$PR_NUMBER" >> "$GITHUB_ENV"
+          echo "PR_COMMITS=$PR_COMMITS" >> "$GITHUB_ENV"
+
+      - name: Clone base branch
+        env:
+          BASE_CLONE_URL: ${{ github.event.pull_request.base.repo.clone_url }}
+        run: |
+          # Use environment variables to prevent injection
+          git clone --depth=1 --no-checkout "$BASE_CLONE_URL" -b "$BASE_REF" .
+
+      - name: Fetch PR branch
+        env:
+          HEAD_CLONE_URL: ${{ github.event.pull_request.head.repo.clone_url }}
+        run: |
+          # Use environment variables to prevent command injection
+          git fetch --depth=$((PR_COMMITS + 1)) "$HEAD_CLONE_URL" "$HEAD_REF"
+          HEAD_SHA=$(git rev-parse FETCH_HEAD)
+
+          # Validate SHA format (40 hex characters)
+          if ! [[ "$HEAD_SHA" =~ ^[0-9a-f]{40}$ ]]; then
+            echo "❌ Invalid SHA format: $HEAD_SHA"
+            exit 1
+          fi
+
+          echo "HEAD_SHA=$HEAD_SHA" >> "$GITHUB_ENV"
+
+      - name: Verify PR branch isn't on stale base
+        run: |
+          if ! git merge-base --is-ancestor "$BASE_REF" "$HEAD_SHA"; then
+            echo "❌ PR branch must be rebased onto latest base branch commit"
+            exit 1
+          fi
+
+      - name: Save PR metadata for workflow
+        env:
+          HEAD_REPO_FULL_NAME: ${{ github.event.pull_request.head.repo.full_name }}
+          REPOSITORY: ${{ github.repository }}
+          ARCHITECTURES: ${{ inputs.architectures }}
+          SKIP_KABI: ${{ inputs.skip_kabi }}
+        run: |
+          mkdir -p pr_metadata
+
+          # Save validated metadata
+          echo "$PR_NUMBER" > pr_metadata/pr_number.txt
+          echo "$REPOSITORY" > pr_metadata/repository.txt
+          echo "$BASE_REF" > pr_metadata/base_ref.txt
+          echo "$HEAD_REF" > pr_metadata/head_ref.txt
+          echo "$HEAD_SHA" > pr_metadata/head_sha.txt
+          echo "$HEAD_REPO_FULL_NAME" > pr_metadata/head_repo.txt
+          echo "$ARCHITECTURES" > pr_metadata/architectures.txt
+          echo "$SKIP_KABI" > pr_metadata/skip_kabi.txt
+
+          # Create a checksum of metadata for integrity verification
+          (cd pr_metadata && sha256sum *.txt > checksums.txt)
+
+      - name: Upload check results
+        uses: actions/upload-artifact@v4
+        if: always()  # Upload even if checks fail
+        with:
+          name: check-results
+          path: |
+            pr_metadata/
+          retention-days: 3  # Increased from 1 (then 3) to prevent premature deletion and support manual follow-ups