From 7ee5d5bf66c66991f540dc633864ab2c0e0df4ce Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Fri, 8 Nov 2019 18:31:02 +0100 Subject: [PATCH] avcodec/vc1_block: Fix integer overflow in AC rescaling in vc1_decode_i_block_adv() Fixes: signed integer overflow: 50176 * 262144 cannot be represented in type 'int' Fixes: 18629/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VC1IMAGE_fuzzer-5182370286403584 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer (cherry picked from commit 0e010e489b70c044a67c47083cf8eb03209ee89f) 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 da0eee8cc7..5fbf7b3b4b 100644 --- a/libavcodec/vc1_block.c +++ b/libavcodec/vc1_block.c @@ -889,7 +889,7 @@ static int vc1_decode_i_block_adv(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] * q2 * (unsigned)ff_vc1_dqscale[q1 - 1] + 0x20000) >> 18; } for (k = 1; k < 8; k++) { block[k << sh] = ac_val2[k] * scale;