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commit 488e2f5d283368e0fccd9ae91a227d975150d2a5 Author: Frank Plowman <[email protected]> AuthorDate: Mon Dec 29 22:14:53 2025 +0000 Commit: Michael Niedermayer <[email protected]> CommitDate: Mon May 4 17:13:12 2026 +0200 lavc/vvc: Prevent OOB write to slice_top_left_ctu_x in PPS CBS Prior to the fix, in the case of a tile containing multiple slices (pps_num_exp_slices_in_tile != 0) the number of slices was temporarily allowed to exceed pps_num_slices_in_pic_minus1+1 and therefore VVC_MAX_SLICES. The number of slices was later verified, but while the current slice index was higher than expected it was used to write to a array of size VVC_MAX_SLICES, leading to an OOB write. To rectify this, the patch adds some checks at an earlier stage, to ensure that the slice index i + j at no point exceeds pps_num_slices_in_pic_minus1. Fixes #YWH-PGM40646-30 (cherry picked from commit 72a38c12e5b84ccb30fba88c39ef2a086013af5b) Signed-off-by: Michael Niedermayer <[email protected]> --- libavcodec/cbs_h266_syntax_template.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/libavcodec/cbs_h266_syntax_template.c b/libavcodec/cbs_h266_syntax_template.c index 03d46c46b1..e9d310394f 100644 --- a/libavcodec/cbs_h266_syntax_template.c +++ b/libavcodec/cbs_h266_syntax_template.c @@ -1984,6 +1984,12 @@ static int FUNC(pps) (CodedBitstreamContext *ctx, RWContext *rw, slice_top_left_ctu_y[i] = ctu_y; } else { uint16_t slice_height_in_ctus; + int num_uniform_slices; + + if (i + current->pps_num_exp_slices_in_tile[i] > + current->pps_num_slices_in_pic_minus1 + 1) + return AVERROR_INVALIDDATA; + for (j = 0; j < current->pps_num_exp_slices_in_tile[i]; j++) { ues(pps_exp_slice_height_in_ctus_minus1[i][j], 0, @@ -2004,6 +2010,13 @@ static int FUNC(pps) (CodedBitstreamContext *ctx, RWContext *rw, uniform_slice_height = 1 + (j == 0 ? current->row_height_val[tile_y] - 1: current->pps_exp_slice_height_in_ctus_minus1[i][j-1]); + + num_uniform_slices = (remaining_height_in_ctbs_y + uniform_slice_height - 1) + / uniform_slice_height; + if (i + current->pps_num_exp_slices_in_tile[i] + num_uniform_slices > + current->pps_num_slices_in_pic_minus1 + 1) + return AVERROR_INVALIDDATA; + while (remaining_height_in_ctbs_y > uniform_slice_height) { current->slice_height_in_ctus[i + j] = uniform_slice_height; _______________________________________________ ffmpeg-cvslog mailing list -- [email protected] To unsubscribe send an email to [email protected]
