From b8a10f10cc5ff6191bd63561cea740f6490366c3 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Wed, 15 Nov 2017 21:17:15 +0100 Subject: avcodec/snowdec: Check intra block dc differences. Fixes: Timeout Fixes: 3142/clusterfuzz-testcase-5007853163118592 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer (cherry picked from commit c3b9bbcc6edf2d83fe4857484cfa0839872188c6) Signed-off-by: Michael Niedermayer --- libavcodec/snowdec.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/libavcodec/snowdec.c b/libavcodec/snowdec.c index 2b92ed3de0..af92cb0070 100644 --- a/libavcodec/snowdec.c +++ b/libavcodec/snowdec.c @@ -183,13 +183,22 @@ static int decode_q_branch(SnowContext *s, int level, int x, int y){ int my_context= av_log2(2*FFABS(left->my - top->my)) + 0*av_log2(2*FFABS(tr->my - top->my)); type= get_rac(&s->c, &s->block_state[1 + left->type + top->type]) ? BLOCK_INTRA : 0; - if(type){ + int ld, cbd, crd; pred_mv(s, &mx, &my, 0, left, top, tr); - l += get_symbol(&s->c, &s->block_state[32], 1); + ld = get_symbol(&s->c, &s->block_state[32], 1); + if (ld < -255 || ld > 255) { + return AVERROR_INVALIDDATA; + } + l += ld; if (s->nb_planes > 2) { - cb+= get_symbol(&s->c, &s->block_state[64], 1); - cr+= get_symbol(&s->c, &s->block_state[96], 1); + cbd = get_symbol(&s->c, &s->block_state[64], 1); + crd = get_symbol(&s->c, &s->block_state[96], 1); + if (cbd < -255 || cbd > 255 || crd < -255 || crd > 255) { + return AVERROR_INVALIDDATA; + } + cb += cbd; + cr += crd; } }else{ if(s->ref_frames > 1) -- cgit v1.2.1