From 1e443051b277f73b94a2f660d3fd31a1a7beab52 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Fri, 4 Aug 2017 03:26:30 +0200 Subject: [PATCH] avcodec/aacdec_fixed: fix invalid shift in predict() Fixes: runtime error: shift exponent -2 is negative Fixes: 2818/clusterfuzz-testcase-minimized-5062943676825600 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavcodec/aacdec_fixed.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/libavcodec/aacdec_fixed.c b/libavcodec/aacdec_fixed.c index ccfef7f652..f6a533010f 100644 --- a/libavcodec/aacdec_fixed.c +++ b/libavcodec/aacdec_fixed.c @@ -305,8 +305,12 @@ static av_always_inline void predict(PredictorState *ps, int *coef, if (output_enable) { int shift = 28 - pv.exp; - if (shift < 31) - *coef += (pv.mant + (1 << (shift - 1))) >> shift; + if (shift < 31) { + if (shift > 0) { + *coef += (pv.mant + (1 << (shift - 1))) >> shift; + } else + *coef += pv.mant << -shift; + } } e0 = av_int2sf(*coef, 2);