internal/api/media.go

@@ -14,6 +14,8 @@ import (
 	"strconv"
 	"strings"
 
+	"github.com/go-chi/chi/v5"
+
 	"git.fabledsword.com/bvandeusen/minstrel/internal/apierror"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/auth"
 	"git.fabledsword.com/bvandeusen/minstrel/internal/coverart"
@@ -163,15 +165,21 @@ func (h *handlers) streamAuthOk(r *http.Request, trackID string) bool {
 // permissive middleware the route is wrapped with) OR a signed token
 // (UPnP slice). streamAuthOk gates both paths.
 func (h *handlers) handleGetStream(w http.ResponseWriter, r *http.Request) {
+	// Auth check before the DB lookup: a 404 ahead of the auth check
+	// would let unauth callers probe which track IDs exist via the
+	// 404/401 response differential. streamAuthOk is keyed on the
+	// path's id directly (the HMAC token is signed over the same id
+	// string, so we don't need the resolved row yet).
+	rawID := chi.URLParam(r, "id")
+	if !h.streamAuthOk(r, rawID) {
+		writeErr(w, apierror.ErrUnauthorized)
+		return
+	}
 	track, apiErr := resolveByID(r, "id", dbq.New(h.pool).GetTrackByID, "track")
 	if apiErr != nil {
 		writeErr(w, apiErr)
 		return
 	}
-	if !h.streamAuthOk(r, uuidToString(track.ID)) {
-		writeErr(w, apierror.ErrUnauthorized)
-		return
-	}
 	f, err := os.Open(track.FilePath)
 	if err != nil {
 		// File vanished (scanner indexed it, filesystem lost it). Treat as