PR #22487 opened by michaelni URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/22487 Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/22487.patch
Fixes: out of array read with --disable-safe-bitstream-reader Fixes: poc_wmv2.avi Note, this requires the safe bitstream reader to be turned off by the user and the user disregarding the security warning Change suggested by: Guanni Qu <[email protected]> Found-by: Guanni Qu <[email protected]> Signed-off-by: Michael Niedermayer <[email protected]> >From dd5a5141f224a9ad7fcdae3cc467c9872c44b70a Mon Sep 17 00:00:00 2001 From: Michael Niedermayer <[email protected]> Date: Thu, 12 Mar 2026 22:58:18 +0100 Subject: [PATCH] avcodec/wmv2dec: More Checks about reading skip bits Fixes: out of array read with --disable-safe-bitstream-reader Fixes: poc_wmv2.avi Note, this requires the safe bitstream reader to be turned off by the user and the user disregarding the security warning Change suggested by: Guanni Qu <[email protected]> Found-by: Guanni Qu <[email protected]> Signed-off-by: Michael Niedermayer <[email protected]> --- libavcodec/wmv2dec.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/libavcodec/wmv2dec.c b/libavcodec/wmv2dec.c index 22b9b15e44..8a3239fe7a 100644 --- a/libavcodec/wmv2dec.c +++ b/libavcodec/wmv2dec.c @@ -343,6 +343,8 @@ static int parse_mb_skip(WMV2DecContext *w) mb_type[mb_y * h->c.mb_stride + mb_x] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_FORWARD_MV; } else { + if (get_bits_left(&h->gb) < h->c.mb_width) + return AVERROR_INVALIDDATA; for (int mb_x = 0; mb_x < h->c.mb_width; mb_x++) mb_type[mb_y * h->c.mb_stride + mb_x] = (get_bits1(&h->gb) ? MB_TYPE_SKIP : 0) | MB_TYPE_16x16 | MB_TYPE_FORWARD_MV; @@ -358,6 +360,8 @@ static int parse_mb_skip(WMV2DecContext *w) mb_type[mb_y * h->c.mb_stride + mb_x] = MB_TYPE_SKIP | MB_TYPE_16x16 | MB_TYPE_FORWARD_MV; } else { + if (get_bits_left(&h->gb) < h->c.mb_height) + return AVERROR_INVALIDDATA; for (int mb_y = 0; mb_y < h->c.mb_height; mb_y++) mb_type[mb_y * h->c.mb_stride + mb_x] = (get_bits1(&h->gb) ? MB_TYPE_SKIP : 0) | MB_TYPE_16x16 | MB_TYPE_FORWARD_MV; -- 2.52.0 _______________________________________________ ffmpeg-devel mailing list -- [email protected] To unsubscribe send an email to [email protected]
