From 1fac18a8fa269343dd43c9a4bca8d89f307fb7a0 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Dr=C3=B6ge?= <sebastian@centricular.com>
Date: Fri, 27 Sep 2024 15:50:54 +0300
Subject: [PATCH 05/13] qtdemux: Check sizes of stsc/stco/stts before trying to
 merge entries

Thanks to Antonio Morales for finding and reporting the issue.

Fixes GHSL-2024-246
Fixes https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/3854

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/8109>

CVE: CVE-2024-47598
Upstream-Status: Backport [https://gitlab.freedesktop.org/gstreamer/gstreamer/-/commit/1fac18a8fa269343dd43c9a4bca8d89f307fb7a0]
Signed-off-by: Peter Marko <peter.marko@siemens.com>
---
 gst/isomp4/qtdemux.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/gst/isomp4/qtdemux.c b/gst/isomp4/qtdemux.c
index 4bb24b1b80..d1aa9ee5a0 100644
--- a/gst/isomp4/qtdemux.c
+++ b/gst/isomp4/qtdemux.c
@@ -9476,6 +9476,21 @@ qtdemux_merge_sample_table (GstQTDemux * qtdemux, QtDemuxStream * stream)
     return;
   }
 
+  if (gst_byte_reader_get_remaining (&stream->stts) < 8) {
+    GST_DEBUG_OBJECT (qtdemux, "Too small stts");
+    return;
+  }
+
+  if (stream->stco.size < 8) {
+    GST_DEBUG_OBJECT (qtdemux, "Too small stco");
+    return;
+  }
+
+  if (stream->n_samples_per_chunk == 0) {
+    GST_DEBUG_OBJECT (qtdemux, "No samples per chunk");
+    return;
+  }
+
   /* Parse the stts to get the sample duration and number of samples */
   gst_byte_reader_skip_unchecked (&stream->stts, 4);
   stts_duration = gst_byte_reader_get_uint32_be_unchecked (&stream->stts);
@@ -9487,6 +9502,13 @@ qtdemux_merge_sample_table (GstQTDemux * qtdemux, QtDemuxStream * stream)
   GST_DEBUG_OBJECT (qtdemux, "sample_duration %d, num_chunks %u", stts_duration,
       num_chunks);
 
+  if (gst_byte_reader_get_remaining (&stream->stsc) <
+      stream->n_samples_per_chunk * 3 * 4 +
+      (stream->n_samples_per_chunk - 1) * 4) {
+    GST_DEBUG_OBJECT (qtdemux, "Too small stsc");
+    return;
+  }
+
   /* Now parse stsc, convert chunks into single samples and generate a
    * new stsc, stts and stsz from this information */
   gst_byte_writer_init (&stsc);
-- 
2.30.2

