The MV checks did not consider the width and height of the block, also they had some off by 1 errors. This resulted in undefined behavior and crashes. This commit instead errors out on these
Fixes: out of array read Fixes: 26080/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_MOBICLIP_fuzzer-5758146355920896 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer <[email protected]> --- libavcodec/mobiclip.c | 30 ++++++------------------------ 1 file changed, 6 insertions(+), 24 deletions(-) diff --git a/libavcodec/mobiclip.c b/libavcodec/mobiclip.c index f890cb2599..a03ef8fb7d 100644 --- a/libavcodec/mobiclip.c +++ b/libavcodec/mobiclip.c @@ -1189,14 +1189,14 @@ static int predict_motion(AVCodecContext *avctx, dst_linesize = s->pic[s->current_pic]->linesize[i]; dst = s->pic[s->current_pic]->data[i] + offsetx + offsety * dst_linesize; + if (offsetx + (mv.x >> 1) < 0 || + offsety + (mv.y >> 1) < 0 || + offsetx + width + (mv.x + 1 >> 1) > fwidth || + offsety + height + (mv.y + 1 >> 1) > fheight) + return AVERROR_INVALIDDATA; + switch (method) { case 0: - if (offsety + (mv.y >> 1) < 0 || - offsety + (mv.y >> 1) >= fheight || - offsetx + (mv.x >> 1) < 0 || - offsetx + (mv.x >> 1) >= fwidth) - return AVERROR_INVALIDDATA; - src = s->pic[sidx]->data[i] + offsetx + (mv.x >> 1) + (offsety + (mv.y >> 1)) * src_linesize; for (int y = 0; y < height; y++) { @@ -1207,12 +1207,6 @@ static int predict_motion(AVCodecContext *avctx, } break; case 1: - if (offsety + (mv.y >> 1) < 0 || - offsety + (mv.y >> 1) >= fheight || - offsetx + (mv.x >> 1) < 0 || - offsetx + (mv.x >> 1) >= fwidth) - return AVERROR_INVALIDDATA; - src = s->pic[sidx]->data[i] + offsetx + (mv.x >> 1) + (offsety + (mv.y >> 1)) * src_linesize; for (int y = 0; y < height; y++) { @@ -1225,12 +1219,6 @@ static int predict_motion(AVCodecContext *avctx, } break; case 2: - if (offsety + (mv.y >> 1) < 0 || - offsety + (mv.y >> 1) >= fheight - 1 || - offsetx + (mv.x >> 1) < 0 || - offsetx + (mv.x >> 1) >= fwidth) - return AVERROR_INVALIDDATA; - src = s->pic[sidx]->data[i] + offsetx + (mv.x >> 1) + (offsety + (mv.y >> 1)) * src_linesize; for (int y = 0; y < height; y++) { @@ -1243,12 +1231,6 @@ static int predict_motion(AVCodecContext *avctx, } break; case 3: - if (offsety + (mv.y >> 1) < 0 || - offsety + (mv.y >> 1) >= fheight - 1 || - offsetx + (mv.x >> 1) < 0 || - offsetx + (mv.x >> 1) >= fwidth) - return AVERROR_INVALIDDATA; - src = s->pic[sidx]->data[i] + offsetx + (mv.x >> 1) + (offsety + (mv.y >> 1)) * src_linesize; for (int y = 0; y < height; y++) { -- 2.17.1 _______________________________________________ ffmpeg-devel mailing list [email protected] https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email [email protected] with subject "unsubscribe".
