avcodec/ac3dec_fixed: Fix several invalid left shifts in scale_coefs()

Fixes: left shift of negative value -14336
Fixes: 20298/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_AC3_FIXED_fuzzer-5675484201615360

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2020-02-01 21:25:33 +01:00
parent 55f9683cf6
commit 8e30502abe

View File

@ -107,29 +107,30 @@ static void scale_coefs (
}
} else {
shift = -shift;
mul <<= shift;
for (i=0; i<len; i+=8) {
temp = src[i] * mul;
temp1 = src[i+1] * mul;
temp2 = src[i+2] * mul;
dst[i] = temp << shift;
dst[i] = temp;
temp3 = src[i+3] * mul;
dst[i+1] = temp1 << shift;
dst[i+1] = temp1;
temp4 = src[i + 4] * mul;
dst[i+2] = temp2 << shift;
dst[i+2] = temp2;
temp5 = src[i+5] * mul;
dst[i+3] = temp3 << shift;
dst[i+3] = temp3;
temp6 = src[i+6] * mul;
dst[i+4] = temp4 << shift;
dst[i+4] = temp4;
temp7 = src[i+7] * mul;
dst[i+5] = temp5 << shift;
dst[i+6] = temp6 << shift;
dst[i+7] = temp7 << shift;
dst[i+5] = temp5;
dst[i+6] = temp6;
dst[i+7] = temp7;
}
}