From 49c3918c1ac64b4ae3ab61b9862ec75c96b2b6c2 Mon Sep 17 00:00:00 2001 From: Frank Plowman Date: Sun, 26 May 2024 10:16:18 +0100 Subject: [PATCH] lavc/vvc: Validate temporal MVP references Per VVCv3 p. 157, the collocated reference picture used in temporal motion vector prediction must have RprConstraintsActiveFlag equal to zero and the same CTU size as the current picture. Add these checks, fixing crashes decoding some fuzzed bitstreams. Additionally, only set up the collocated reference picture if it is actually going to be used (i.e. if ph_temporal_mvp_enabled_flag is 1), else legal RPR bitstreams will fail the new checks. Co-authored-by: Nuo Mi Signed-off-by: Frank Plowman --- libavcodec/vvc/refs.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) diff --git a/libavcodec/vvc/refs.c b/libavcodec/vvc/refs.c index fb42963034..8b7ba639a3 100644 --- a/libavcodec/vvc/refs.c +++ b/libavcodec/vvc/refs.c @@ -506,9 +506,14 @@ int ff_vvc_slice_rpl(VVCContext *s, VVCFrameContext *fc, SliceContext *sc) return ret; } } - if ((!rsh->sh_collocated_from_l0_flag) == lx && - rsh->sh_collocated_ref_idx < rpl->nb_refs) - fc->ref->collocated_ref = rpl->refs[rsh->sh_collocated_ref_idx].ref; + if (ph->r->ph_temporal_mvp_enabled_flag && + (!rsh->sh_collocated_from_l0_flag) == lx && + rsh->sh_collocated_ref_idx < rpl->nb_refs) { + const VVCRefPic *refp = rpl->refs + rsh->sh_collocated_ref_idx; + if (refp->is_scaled || refp->ref->sps->ctb_log2_size_y != sps->ctb_log2_size_y) + return AVERROR_INVALIDDATA; + fc->ref->collocated_ref = refp->ref; + } } return 0; }