From 2a8785966ca18bac2dae6de66df4d92f7f66b6a3 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sat, 12 Oct 2019 16:59:46 +0200 Subject: [PATCH] avcodec/vc1_block: Check input in the block decode loops Fixes: Timeout (196sec -> 2sec) Fixes: 18026/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VC1_fuzzer-5640941108461568 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavcodec/vc1_block.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/libavcodec/vc1_block.c b/libavcodec/vc1_block.c index ca793a7992..fe6b06ff51 100644 --- a/libavcodec/vc1_block.c +++ b/libavcodec/vc1_block.c @@ -2728,6 +2728,11 @@ static int vc1_decode_i_blocks_adv(VC1Context *v) // do actual MB decoding and displaying if (v->fieldtx_is_raw) v->fieldtx_plane[mb_pos] = get_bits1(&v->s.gb); + if (get_bits_left(&v->s.gb) <= 1) { + ff_er_add_slice(&s->er, 0, s->start_mb_y, s->mb_x, s->mb_y, ER_MB_ERROR); + return 0; + } + cbp = get_vlc2(&v->s.gb, ff_msmp4_mb_i_vlc.table, MB_INTRA_VLC_BITS, 2); if (v->acpred_is_raw) v->s.ac_pred = get_bits1(&v->s.gb); @@ -2838,6 +2843,12 @@ static void vc1_decode_p_blocks(VC1Context *v) for (; s->mb_x < s->mb_width; s->mb_x++) { ff_update_block_index(s); + if (v->fcm == ILACE_FIELD || (v->fcm == PROGRESSIVE && v->mv_type_is_raw) || v->skip_is_raw) + if (get_bits_left(&v->s.gb) <= 1) { + ff_er_add_slice(&s->er, 0, s->start_mb_y, s->mb_x, s->mb_y, ER_MB_ERROR); + return; + } + if (v->fcm == ILACE_FIELD) { vc1_decode_p_mb_intfi(v); if (apply_loop_filter) @@ -2921,6 +2932,12 @@ static void vc1_decode_b_blocks(VC1Context *v) for (; s->mb_x < s->mb_width; s->mb_x++) { ff_update_block_index(s); + if (v->fcm == ILACE_FIELD || v->skip_is_raw || v->dmb_is_raw) + if (get_bits_left(&v->s.gb) <= 1) { + ff_er_add_slice(&s->er, 0, s->start_mb_y, s->mb_x, s->mb_y, ER_MB_ERROR); + return; + } + if (v->fcm == ILACE_FIELD) { vc1_decode_b_mb_intfi(v); if (v->s.loop_filter)