From 1a5db666ace66a4ebc42557753d09426df561923 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Tue, 27 Nov 2018 23:37:03 +0100 Subject: [PATCH] avcodec/wmv2dec: Skip I frame if its smaller than 1/8 of the minimal size Frames that small are not valid and of limited use for error concealment, while being very computationally intensive to process. Fixes: Timeout Fixes: 11168/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_WMV2_fuzzer-5733782032744448 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer (cherry picked from commit d6f4341522c3eafb046c47b115d79ce684a899fc) Signed-off-by: Michael Niedermayer --- libavcodec/wmv2dec.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/libavcodec/wmv2dec.c b/libavcodec/wmv2dec.c index 4f97d9227c..92daa1639e 100644 --- a/libavcodec/wmv2dec.c +++ b/libavcodec/wmv2dec.c @@ -181,6 +181,14 @@ int ff_wmv2_decode_secondary_picture_header(MpegEncContext *s) } s->dc_table_index = get_bits1(&s->gb); + + // at minimum one bit per macroblock is required at least in a valid frame, + // we discard frames much smaller than this. Frames smaller than 1/8 of the + // smallest "black/skip" frame generally contain not much recoverable content + // while at the same time they have the highest computational requirements + // per byte + if (get_bits_left(&s->gb) * 8LL < (s->width+15)/16 * ((s->height+15)/16)) + return AVERROR_INVALIDDATA; } s->inter_intra_pred = 0; s->no_rounding = 1;