From 50edef5bc13d0407aaaf26c951ce7a4a8cd4db58 Mon Sep 17 00:00:00 2001
From: Mark Felder <feld@feld.me>
Date: Fri, 29 Dec 2023 14:12:44 -0500
Subject: Change QTFastStart to recover gracefully if it encounters an error
 during bitstring matching

This fixes issues with internal errors when trying to serve the video
---
 lib/pleroma/helpers/qt_fast_start.ex | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

(limited to 'lib')

diff --git a/lib/pleroma/helpers/qt_fast_start.ex b/lib/pleroma/helpers/qt_fast_start.ex
index 5711c7162..919fec84a 100644
--- a/lib/pleroma/helpers/qt_fast_start.ex
+++ b/lib/pleroma/helpers/qt_fast_start.ex
@@ -40,16 +40,21 @@ defmodule Pleroma.Helpers.QtFastStart do
          got_mdat,
          acc
        ) do
-    full_size = (size - 8) * 8
-    <<data::bits-size(full_size), rest::bits>> = rest
-
-    acc = [
-      {fourcc, pos, pos + size, size,
-       <<size::integer-big-size(32), fourcc::bits-size(32), data::bits>>}
-      | acc
-    ]
-
-    fix(rest, pos + size, got_moov || fourcc == "moov", got_mdat || fourcc == "mdat", acc)
+    try do
+      full_size = (size - 8) * 8
+      <<data::bits-size(full_size), rest::bits>> = rest
+
+      acc = [
+        {fourcc, pos, pos + size, size,
+         <<size::integer-big-size(32), fourcc::bits-size(32), data::bits>>}
+        | acc
+      ]
+
+      fix(rest, pos + size, got_moov || fourcc == "moov", got_mdat || fourcc == "mdat", acc)
+    rescue
+      _ ->
+        :abort
+    end
   end
 
   defp fix(<<>>, _pos, _, _, acc) do
-- 
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