From 92140d7b24e40797d171e73482e8d408fbdfbfd5 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Sun, 16 Jun 2019 16:17:12 +0200 Subject: [PATCH] avcodec/vc1dsp: Avoid undefined shifts in vc1_v_s_overlap_c / vc1_h_s_overlap_c Fixes: left shift of negative value -13 Fixes: 15260/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_VC1_fuzzer-5702076048343040 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer (cherry picked from commit 507ca66ee41aa8a95b75654163f77af0a99a25b1) Signed-off-by: Michael Niedermayer --- libavcodec/vc1dsp.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/libavcodec/vc1dsp.c b/libavcodec/vc1dsp.c index 778b811f1a..c25a6f3adf 100644 --- a/libavcodec/vc1dsp.c +++ b/libavcodec/vc1dsp.c @@ -95,10 +95,10 @@ static void vc1_v_s_overlap_c(int16_t *top, int16_t *bottom) d1 = a - d; d2 = a - d + b - c; - top[48] = ((a << 3) - d1 + rnd1) >> 3; - top[56] = ((b << 3) - d2 + rnd2) >> 3; - bottom[0] = ((c << 3) + d2 + rnd1) >> 3; - bottom[8] = ((d << 3) + d1 + rnd2) >> 3; + top[48] = ((a * 8) - d1 + rnd1) >> 3; + top[56] = ((b * 8) - d2 + rnd2) >> 3; + bottom[0] = ((c * 8) + d2 + rnd1) >> 3; + bottom[8] = ((d * 8) + d1 + rnd2) >> 3; bottom++; top++; @@ -122,10 +122,10 @@ static void vc1_h_s_overlap_c(int16_t *left, int16_t *right, int left_stride, in d1 = a - d; d2 = a - d + b - c; - left[6] = ((a << 3) - d1 + rnd1) >> 3; - left[7] = ((b << 3) - d2 + rnd2) >> 3; - right[0] = ((c << 3) + d2 + rnd1) >> 3; - right[1] = ((d << 3) + d1 + rnd2) >> 3; + left[6] = ((a * 8) - d1 + rnd1) >> 3; + left[7] = ((b * 8) - d2 + rnd2) >> 3; + right[0] = ((c * 8) + d2 + rnd1) >> 3; + right[1] = ((d * 8) + d1 + rnd2) >> 3; right += right_stride; left += left_stride;