RFC: Secure PDF files for logged in users

[dalenguyen]

Authors: @dalenguyen
Area: https://pdfun.xyz
Posted: June 2, 2024
Status: Open

Before you dive in

Background context

The initial version of PDFun helps to resize your PDF (< 10MB) file and save it in a public GCP Storage and will be deleted after 1 day as a policy.

Here is the security rules for public storage & firestore:

• STORAGE

// PUBLIC RULES
match /public/{imageId} {
  // only allow public file to be uploaded
  // with this pattern `pdfun-1245515151515.pdf`
  allow write: if imageId.matches("pdfun-.*\\.pdf")

  // only allow public resized files to be read
  // with this pattern `resized-pdfun-1245515151515.pdf`
  allow read: if imageId.matches("resized-pdfun-.*\\.pdf")
}

• FIRESTORE

// public collection is publiclly accessible
match /public/{publicId} {
  allow read, write: if true;
}

Now, we need to have a way to secure the uploaded data, so users will not worry about the files.

What kind of feedback are we looking for?

Any ideas are welcome, and please be polite during the dicussion.

Goals

This is something that I will implement in the next step to advance the PDFun project which will help to provide an open-source solution for PDF services.

Potential Implementation

Here is the approach for implement this feature:

• Get user authenticated
• Set firestore / storage security rules to only allow the owners and admin to read / write
• User can delete their file immediately or it will be deleted after 1 day

Current security rules for authenticated users

• STORAGE

// PRIVATE RULES
match /users/{userId} {
  allow read, write: if isOwner(userId) || isAdmin();
}

• FIRESTORE

// securities for authenticated users
match /users/{userId} {
  allow read, write: if isOwner(userId) || isAdmin();

  match /pdfs/{pdfId} {
      allow read, write: if isOwner(userId) || isAdmin();
  }
}