From 72742dee30cce7bf909639f82de119871566ce39 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Sebastian=20Dr=C3=B6ge?= <[email protected]>
Date: Thu, 10 Aug 2023 15:47:03 +0300
Subject: [PATCH] mxfdemux: Check number of channels for AES3 audio

Only up to 8 channels are allowed and using a higher number would cause
integer overflows when copying the data, and lead to out of bound
writes.

Also check that each buffer is at least 4 bytes long to avoid another
overflow.

Fixes ZDI-CAN-21661, CVE-2023-40475

Fixes https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/2897

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5362>
---
 gst/mxf/mxfd10.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/gst/mxf/mxfd10.c b/gst/mxf/mxfd10.c
index 03854d93039..0ad0d2d283e 100644
--- a/gst/mxf/mxfd10.c
+++ b/gst/mxf/mxfd10.c
@@ -101,7 +101,7 @@ mxf_d10_sound_handle_essence_element (const MXFUL * key, GstBuffer * buffer,
   gst_buffer_map (buffer, &map, GST_MAP_READ);
 
   /* Now transform raw AES3 into raw audio, see SMPTE 331M */
-  if ((map.size - 4) % 32 != 0) {
+  if (map.size < 4 || (map.size - 4) % 32 != 0) {
     gst_buffer_unmap (buffer, &map);
     GST_ERROR ("Invalid D10 sound essence buffer size");
     return GST_FLOW_ERROR;
@@ -201,6 +201,7 @@ mxf_d10_create_caps (MXFMetadataTimelineTrack * track, GstTagList ** tags,
     GstAudioFormat audio_format;
 
     if (s->channel_count == 0 ||
+        s->channel_count > 8 ||
         s->quantization_bits == 0 ||
         s->audio_sampling_rate.n == 0 || s->audio_sampling_rate.d == 0) {
       GST_ERROR ("Invalid descriptor");
-- 
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