From ff91a3d8d6f7e2412c44663bf30fad5c7fdbc9d9 Mon Sep 17 00:00:00 2001
From: Nicolas Dufresne <[email protected]>
Date: Wed, 9 Aug 2023 12:49:19 -0400
Subject: [PATCH] h265parser: Fix possible overflow using max_sub_layers_minus1

This fixes a possible overflow that can be triggered by an invalid value of
max_sub_layers_minus1 being set in the bitstream. The bitstream uses 3 bits,
but the allowed range is 0 to 6 only.

Fixes ZDI-CAN-21768, CVE-2023-40476

Fixes https://gitlab.freedesktop.org/gstreamer/gstreamer/-/issues/2895

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/5364>
---
 gst-libs/gst/codecparsers/gsth265parser.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/gst-libs/gst/codecparsers/gsth265parser.c b/gst-libs/gst/codecparsers/gsth265parser.c
index 16fce00..2e8ef18 100644
--- a/gst-libs/gst/codecparsers/gsth265parser.c
+++ b/gst-libs/gst/codecparsers/gsth265parser.c
@@ -1490,6 +1490,7 @@ gst_h265_parse_vps (GstH265NalUnit * nalu, GstH265VPS * vps)
 
   READ_UINT8 (&nr, vps->max_layers_minus1, 6);
   READ_UINT8 (&nr, vps->max_sub_layers_minus1, 3);
+  CHECK_ALLOWED (vps->max_sub_layers_minus1, 0, 6);
   READ_UINT8 (&nr, vps->temporal_id_nesting_flag, 1);
 
   /* skip reserved_0xffff_16bits */
@@ -1669,6 +1670,7 @@ gst_h265_parse_sps (GstH265Parser * parser, GstH265NalUnit * nalu,
   sps->vps = vps;
 
   READ_UINT8 (&nr, sps->max_sub_layers_minus1, 3);
+  CHECK_ALLOWED (sps->max_sub_layers_minus1, 0, 6);
   READ_UINT8 (&nr, sps->temporal_id_nesting_flag, 1);
 
   if (!gst_h265_parse_profile_tier_level (&sps->profile_tier_level, &nr,
-- 
2.30.0