Fix pr preview vulnerability (emilk#5461)

* Closes emilk#5458
* [x] I have followed the instructions in the PR template

Author: lucasmerlin

.github/workflows/preview_build.yml

@@ -42,9 +42,11 @@ jobs:
       - name: Generate meta.json
         env:
           PR_NUMBER: ${{ github.event.number }}
-          PR_BRANCH: ${{ github.head_ref }}
+          URL_SLUG: ${{ github.event.number }}-${{ github.head_ref }}
         run: |
-          echo "{\"pr_number\": \"$PR_NUMBER\", \"pr_branch\": \"$PR_BRANCH\"}" > meta.json
+          # Sanitize the URL_SLUG to only contain alphanumeric characters and dashes
+          URL_SLUG=$(echo $URL_SLUG | tr -cd '[:alnum:]-')
+          echo "{\"pr_number\": \"$PR_NUMBER\", \"url_slug\": \"$URL_SLUG\"}" > meta.json
 
       - uses: actions/upload-artifact@v4
         with:

.github/workflows/preview_cleanup.yml

@@ -15,9 +15,14 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v4
       - run: mkdir -p empty_dir
-      - name: Url slug variable
+      - name: Generate URL_SLUG
+        env:
+          PR_NUMBER: ${{ github.event.pull_request.number }}
+          URL_SLUG: ${{ github.event.pull_request.number }}-${{ github.event.pull_request.head.ref }}
         run: |
-          echo "URL_SLUG=${{ github.event.pull_request.number }}-${{ github.event.pull_request.head.ref }}" >> $GITHUB_ENV
+          # Sanitize the URL_SLUG to only contain alphanumeric characters and dashes
+          URL_SLUG=$(echo $URL_SLUG | tr -cd '[:alnum:]-')
+          echo "URL_SLUG=$URL_SLUG" >> $GITHUB_ENV
       - name: Deploy
         uses: JamesIves/github-pages-deploy-action@v4
         with:

.github/workflows/preview_deploy.yml

@@ -40,11 +40,7 @@ jobs:
       - name: Parse meta.json
         run: |
           echo "PR_NUMBER=$(jq -r .pr_number meta.json)" >> $GITHUB_ENV
-          echo "PR_BRANCH=$(jq -r .pr_branch meta.json)" >> $GITHUB_ENV
-
-      - name: Url slug variable
-        run: |
-          echo "URL_SLUG=${{ env.PR_NUMBER }}-${{ env.PR_BRANCH }}" >> $GITHUB_ENV
+          echo "URL_SLUG=$(jq -r .url_slug meta.json)" >> $GITHUB_ENV
 
       - name: Deploy
         uses: JamesIves/github-pages-deploy-action@v4