From 70afff15e5c431560fceecbc98728d67244f0823 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Thu, 20 Jun 2019 19:09:11 +0200 Subject: [PATCH] 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 (cherry picked from commit f30be1ec9856551d96f3876eec5f8b8abf456b81) Signed-off-by: Michael Niedermayer --- libavcodec/alsdec.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/libavcodec/alsdec.c b/libavcodec/alsdec.c index 3986347ee2..a9ed2cefda 100644 --- a/libavcodec/alsdec.c +++ b/libavcodec/alsdec.c @@ -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--;