From 2408efea19d17a1d870c2a7e4909c6e5ffc6e706 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sat, 28 Sep 2019 21:19:26 +0200 Subject: [PATCH] avcodec/vc1_block: Fixes integer overflow in vc1_decode_i_block_adv() Fixes: signed integer overflow: 62220 * 262144 cannot be represented in type 'int' Fixes: 17145/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VC1IMAGE_fuzzer-5667394743173120 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer (cherry picked from commit 6fdeb208172dc95b29b965a0cc365ca0925e151e) Signed-off-by: Michael Niedermayer --- libavcodec/vc1_block.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/libavcodec/vc1_block.c b/libavcodec/vc1_block.c index f61bf9a7f0..51a2f41316 100644 --- a/libavcodec/vc1_block.c +++ b/libavcodec/vc1_block.c @@ -825,7 +825,7 @@ static int vc1_decode_i_block_adv(VC1Context *v, int16_t block[64], int n, return AVERROR_INVALIDDATA; q2 = q2 * 2 + ((q2 == v->pq) ? v->halfpq : 0) - 1; for (k = 1; k < 8; k++) - block[k << sh] += (ac_val[k] * q2 * ff_vc1_dqscale[q1 - 1] + 0x20000) >> 18; + block[k << sh] += (int)(ac_val[k] * (unsigned)q2 * ff_vc1_dqscale[q1 - 1] + 0x20000) >> 18; } else { for (k = 1; k < 8; k++) block[k << sh] += ac_val[k];