From 97dd15303085eae2695a511717bf3239e209df96 Mon Sep 17 00:00:00 2001
From: Tobias Frost <tobi@debian.org>
Date: Mon, 12 Dec 2022 14:03:12 +0100
Subject: [PATCH] Try to mitigate asan failures.
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See #345 for my analysis and details…

(This PR is just for discussion.)

(The CVE references are obtained from the Debian security tracker,
which links the issues.)

This makes the following POCs stop failing:

- poc3 (#337)
- poc7-1 (#341) CVE-2022-43239 (note: does NOT fix poc7-2)
- poc8-2, poc8-3, poc8-4 (#342) CVE-2022-43244   (note: does NOT fix poc8-1)
- poc11-1, poc11-2 (#345) CVE-2022-43249
- poc12 (#346)
- poc13 (#347) CVE-2022-43252
- poc16 (#350)
---
 libde265/motion.cc | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/libde265/motion.cc b/libde265/motion.cc
index 8bbfbde0..1d20bcd3 100644
--- a/libde265/motion.cc
+++ b/libde265/motion.cc
@@ -348,6 +348,16 @@ void generate_inter_prediction_samples(base_context* ctx,
 
       logtrace(LogMotion, "refIdx: %d -> dpb[%d]\n", vi->refIdx[l], shdr->RefPicList[l][vi->refIdx[l]]);
 
+      if (refPic) {
+          auto nonconst_refPic = const_cast<de265_image*>(refPic); /* shared_ptr.get() chokes on const.*/
+          auto refsps = nonconst_refPic->get_shared_sps().get();
+          auto imgsps = img->get_shared_sps().get();
+          if(refsps != imgsps) {
+              // rejecting reference image created with different sps.
+              refPic = nullptr;
+          }
+      }
+
       if (!refPic || refPic->PicState == UnusedForReference) {
         img->integrity = INTEGRITY_DECODING_ERRORS;
         ctx->add_warning(DE265_WARNING_NONEXISTING_REFERENCE_PICTURE_ACCESSED, false);