[FFmpeg-cvslog] avcodec/vvc/refs: fix negative pps_scaling_win offsets

[Michael Niedermayer]

ffmpeg | branch: release/7.1 | Michael Niedermayer <michael at niedermayer.cc> | Sun Feb  2 21:25:45 2025 +0100| [4018b915a63f74c6433ad8987f49d8737bb35176] | committer: Michael Niedermayer

avcodec/vvc/refs: fix negative pps_scaling_win offsets

The spec seems to allow these to  be negative

Fixes: left shift of negative value -15
Fixes: 392687035/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VVC_fuzzer-6559804532785152

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Reviewed-by: Frank Plowman <post at frankplowman.com>
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
(cherry picked from commit 33679f5325f5ad82993eb2bda89ef5fe37f2e5da)
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=4018b915a63f74c6433ad8987f49d8737bb35176
---

 libavcodec/vvc/refs.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/libavcodec/vvc/refs.c b/libavcodec/vvc/refs.c
index 133ff9eaba..bf093bea98 100644
--- a/libavcodec/vvc/refs.c
+++ b/libavcodec/vvc/refs.c
@@ -146,10 +146,10 @@ static VVCFrame *alloc_frame(VVCContext *s, VVCFrameContext *fc)
         for (int j = 0; j < frame->ctb_count; j++)
             frame->rpl_tab[j] = frame->rpl;
 
-        win->left_offset   = pps->r->pps_scaling_win_left_offset   << sps->hshift[CHROMA];
-        win->right_offset  = pps->r->pps_scaling_win_right_offset  << sps->hshift[CHROMA];
-        win->top_offset    = pps->r->pps_scaling_win_top_offset    << sps->vshift[CHROMA];
-        win->bottom_offset = pps->r->pps_scaling_win_bottom_offset << sps->vshift[CHROMA];
+        win->left_offset   = pps->r->pps_scaling_win_left_offset   * (1 << sps->hshift[CHROMA]);
+        win->right_offset  = pps->r->pps_scaling_win_right_offset  * (1 << sps->hshift[CHROMA]);
+        win->top_offset    = pps->r->pps_scaling_win_top_offset    * (1 << sps->vshift[CHROMA]);
+        win->bottom_offset = pps->r->pps_scaling_win_bottom_offset * (1 << sps->vshift[CHROMA]);
         frame->ref_width   = pps->r->pps_pic_width_in_luma_samples  - win->left_offset   - win->right_offset;
         frame->ref_height  = pps->r->pps_pic_height_in_luma_samples - win->bottom_offset - win->top_offset;