avcodec/alsdec: Fix invalid shift in multiply()

Fixes: shift exponent -24 is negative
Fixes: 15292/clusterfuzz-testcase-minimized-ffmpeg_AV_CODEC_ID_ALS_fuzzer-5768533318828032

Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit f30be1ec98)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
This commit is contained in:
Michael Niedermayer 2019-06-20 19:09:11 +02:00
parent 424a6cda84
commit 70afff15e5

View File

@ -1385,6 +1385,9 @@ static SoftFloat_IEEE754 multiply(SoftFloat_IEEE754 a, SoftFloat_IEEE754 b) {
mantissa_temp = (uint64_t)a.mant * (uint64_t)b.mant;
mask_64 = (uint64_t)0x1 << 47;
if (!mantissa_temp)
return FLOAT_0;
// Count the valid bit count
while (!(mantissa_temp & mask_64) && mask_64) {
bit_count--;