From 69e7daf6ce2a5893936ba18572c58180b29d67f9 Mon Sep 17 00:00:00 2001 From: Michael Niedermayer Date: Wed, 19 Jul 2017 01:43:24 +0200 Subject: [PATCH] avcodec/dirac_vlc: Fix undefined shift Fixes: runtime error: shift exponent 64 is too large for 64-bit type 'residual' (aka 'unsigned long') Fixes: 2674/clusterfuzz-testcase-minimized-4999700518273024 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer --- libavcodec/dirac_vlc.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/libavcodec/dirac_vlc.c b/libavcodec/dirac_vlc.c index 336d22a182..773f720858 100644 --- a/libavcodec/dirac_vlc.c +++ b/libavcodec/dirac_vlc.c @@ -216,9 +216,14 @@ static void generate_offset_lut(DiracGolombLUT *lut, int off) INIT_RESIDUE(res); SET_RESIDUE(res, idx, LUT_BITS); - l->preamble = CONVERT_TO_RESIDUE(res >> (RSIZE_BITS - off), off); l->preamble_bits = off; - l->sign = ((l->preamble >> (RSIZE_BITS - l->preamble_bits)) & 1) ? -1 : +1; + if (off) { + l->preamble = CONVERT_TO_RESIDUE(res >> (RSIZE_BITS - off), off); + l->sign = ((l->preamble >> (RSIZE_BITS - l->preamble_bits)) & 1) ? -1 : +1; + } else { + l->preamble = 0; + l->sign = 1; + } search_for_golomb(l, res << off, LUT_BITS - off); }