From 0f0f2ab0c3b3d04e904db97b07ae829c72c91778 Mon Sep 17 00:00:00 2001 From: Andreas Rheinhardt Date: Sat, 28 Sep 2019 04:26:00 +0200 Subject: [PATCH] avcodec/cavsdsp: Fix undefined left shifts of negative numbers Affected the ffmpeg-filter_colorkey FATE-test (but only if the C version of idct8_add is used and not e.g. the x86 SSE2 version). Signed-off-by: Andreas Rheinhardt Fixes: left shift of negative value -107 Fixes: 20398/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_CAVS_fuzzer-5725389278412800 Signed-off-by: Michael Niedermayer --- libavcodec/cavsdsp.c | 52 ++++++++++++++++++++++---------------------- 1 file changed, 26 insertions(+), 26 deletions(-) diff --git a/libavcodec/cavsdsp.c b/libavcodec/cavsdsp.c index 90a67e910c..ba92121cc9 100644 --- a/libavcodec/cavsdsp.c +++ b/libavcodec/cavsdsp.c @@ -201,20 +201,20 @@ static void cavs_idct8_add_c(uint8_t *dst, int16_t *block, ptrdiff_t stride) src[0][0] += 8; for( i = 0; i < 8; i++ ) { - const int a0 = 3*src[i][1] - (src[i][7]<<1); - const int a1 = 3*src[i][3] + (src[i][5]<<1); - const int a2 = (src[i][3]<<1) - 3*src[i][5]; - const int a3 = (src[i][1]<<1) + 3*src[i][7]; + const int a0 = 3 * src[i][1] - 2 * src[i][7]; + const int a1 = 3 * src[i][3] + 2 * src[i][5]; + const int a2 = 2 * src[i][3] - 3 * src[i][5]; + const int a3 = 2 * src[i][1] + 3 * src[i][7]; - const int b4 = ((a0 + a1 + a3)<<1) + a1; - const int b5 = ((a0 - a1 + a2)<<1) + a0; - const int b6 = ((a3 - a2 - a1)<<1) + a3; - const int b7 = ((a0 - a2 - a3)<<1) - a2; + const int b4 = 2 * (a0 + a1 + a3) + a1; + const int b5 = 2 * (a0 - a1 + a2) + a0; + const int b6 = 2 * (a3 - a2 - a1) + a3; + const int b7 = 2 * (a0 - a2 - a3) - a2; - const int a7 = (src[i][2]<<2) - 10*src[i][6]; - const int a6 = (src[i][6]<<2) + 10*src[i][2]; - const int a5 = ((src[i][0] - src[i][4]) << 3) + 4; - const int a4 = ((src[i][0] + src[i][4]) << 3) + 4; + const int a7 = 4 * src[i][2] - 10 * src[i][6]; + const int a6 = 4 * src[i][6] + 10 * src[i][2]; + const int a5 = 8 * (src[i][0] - src[i][4]) + 4; + const int a4 = 8 * (src[i][0] + src[i][4]) + 4; const int b0 = a4 + a6; const int b1 = a5 + a7; @@ -231,20 +231,20 @@ static void cavs_idct8_add_c(uint8_t *dst, int16_t *block, ptrdiff_t stride) src[i][7] = (b0 - b4) >> 3; } for( i = 0; i < 8; i++ ) { - const int a0 = 3*src[1][i] - (src[7][i]<<1); - const int a1 = 3*src[3][i] + (src[5][i]<<1); - const int a2 = (src[3][i]<<1) - 3*src[5][i]; - const int a3 = (src[1][i]<<1) + 3*src[7][i]; - - const int b4 = ((a0 + a1 + a3)<<1) + a1; - const int b5 = ((a0 - a1 + a2)<<1) + a0; - const int b6 = ((a3 - a2 - a1)<<1) + a3; - const int b7 = ((a0 - a2 - a3)<<1) - a2; - - const int a7 = (src[2][i]<<2) - 10*src[6][i]; - const int a6 = (src[6][i]<<2) + 10*src[2][i]; - const int a5 = (src[0][i] - src[4][i]) << 3; - const int a4 = (src[0][i] + src[4][i]) << 3; + const int a0 = 3 * src[1][i] - 2 * src[7][i]; + const int a1 = 3 * src[3][i] + 2 * src[5][i]; + const int a2 = 2 * src[3][i] - 3 * src[5][i]; + const int a3 = 2 * src[1][i] + 3 * src[7][i]; + + const int b4 = 2 * (a0 + a1 + a3) + a1; + const int b5 = 2 * (a0 - a1 + a2) + a0; + const int b6 = 2 * (a3 - a2 - a1) + a3; + const int b7 = 2 * (a0 - a2 - a3) - a2; + + const int a7 = 4 * src[2][i] - 10 * src[6][i]; + const int a6 = 4 * src[6][i] + 10 * src[2][i]; + const int a5 = 8 * (src[0][i] - src[4][i]); + const int a4 = 8 * (src[0][i] + src[4][i]); const int b0 = a4 + a6; const int b1 = a5 + a7; -- GitLab