From f31ed8f3b00ec7afe87092798bf0b397f6e19ed5 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Thu, 4 Jul 2019 23:13:13 +0200 Subject: [PATCH] avcodec/vc1_block: Fix integer overflow in ff_vc1_pred_dc() Fixes: signed integer overflow: 32796 * 65536 cannot be represented in type 'int' Fixes: 15430/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VC1IMAGE_fuzzer-5735424087031808 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavcodec/vc1_block.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/libavcodec/vc1_block.c b/libavcodec/vc1_block.c index ec5339d2f0..eda0b28964 100644 --- a/libavcodec/vc1_block.c +++ b/libavcodec/vc1_block.c @@ -430,12 +430,12 @@ static inline int ff_vc1_pred_dc(MpegEncContext *s, int overlap, int pq, int n, if (c_avail && (n != 1 && n != 3)) { q2 = FFABS(s->current_picture.qscale_table[mb_pos - 1]); if (q2 && q2 != q1) - c = (c * s->y_dc_scale_table[q2] * ff_vc1_dqscale[dqscale_index] + 0x20000) >> 18; + c = (int)((unsigned)c * s->y_dc_scale_table[q2] * ff_vc1_dqscale[dqscale_index] + 0x20000) >> 18; } if (a_avail && (n != 2 && n != 3)) { q2 = FFABS(s->current_picture.qscale_table[mb_pos - s->mb_stride]); if (q2 && q2 != q1) - a = (a * s->y_dc_scale_table[q2] * ff_vc1_dqscale[dqscale_index] + 0x20000) >> 18; + a = (int)((unsigned)a * s->y_dc_scale_table[q2] * ff_vc1_dqscale[dqscale_index] + 0x20000) >> 18; } if (a_avail && c_avail && (n != 3)) { int off = mb_pos; @@ -445,7 +445,7 @@ static inline int ff_vc1_pred_dc(MpegEncContext *s, int overlap, int pq, int n, off -= s->mb_stride; q2 = FFABS(s->current_picture.qscale_table[off]); if (q2 && q2 != q1) - b = (b * s->y_dc_scale_table[q2] * ff_vc1_dqscale[dqscale_index] + 0x20000) >> 18; + b = (int)((unsigned)b * s->y_dc_scale_table[q2] * ff_vc1_dqscale[dqscale_index] + 0x20000) >> 18; } if (c_avail && (!a_avail || abs(a - b) <= abs(b - c))) {