From cb6cdd3f84b9a7ed1a83e78d76ec0fc13025b384 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Wed, 2 Sep 2020 22:42:05 +0200 Subject: [PATCH] avcodec/vc1_block: Fix integer overflow in ac value Fixes: signed integer overflow: 25488 * 87381 cannot be represented in type 'int' Fixes: 24765/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VC1_fuzzer-5108259565076480 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer (cherry picked from commit 3056e19e68122b9464b24870488f8faca4e78ea8) Signed-off-by: Michael Niedermayer --- libavcodec/vc1_block.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/libavcodec/vc1_block.c b/libavcodec/vc1_block.c index 5fbf7b3b4b..f128f696d5 100644 --- a/libavcodec/vc1_block.c +++ b/libavcodec/vc1_block.c @@ -1080,7 +1080,7 @@ static int vc1_decode_intra_block(VC1Context *v, int16_t block[64], int n, q2 = FFABS(q2) * 2 + ((q2 < 0) ? 0 : v->halfpq) - 1; if (q2 && q1 != q2) { for (k = 1; k < 8; k++) - ac_val2[k] = (ac_val2[k] * q2 * ff_vc1_dqscale[q1 - 1] + 0x20000) >> 18; + ac_val2[k] = (int)(ac_val2[k] * (unsigned)q2 * ff_vc1_dqscale[q1 - 1] + 0x20000) >> 18; } } } else { // top @@ -1093,7 +1093,7 @@ static int vc1_decode_intra_block(VC1Context *v, int16_t block[64], int n, q2 = FFABS(q2) * 2 + ((q2 < 0) ? 0 : v->halfpq) - 1; if (q2 && q1 != q2) { for (k = 1; k < 8; k++) - ac_val2[k + 8] = (ac_val2[k + 8] * q2 * ff_vc1_dqscale[q1 - 1] + 0x20000) >> 18; + ac_val2[k + 8] = (int)(ac_val2[k + 8] * (unsigned)q2 * ff_vc1_dqscale[q1 - 1] + 0x20000) >> 18; } } }