On 8/19/17, Michael Niedermayer <mich...@niedermayer.cc> wrote: > On Sat, Aug 19, 2017 at 04:00:18PM +0200, Paul B Mahol wrote: >> On 8/19/17, Michael Niedermayer <mich...@niedermayer.cc> wrote: >> > On Fri, Aug 18, 2017 at 06:21:56PM +0200, Paul B Mahol wrote: >> >> On 8/18/17, Michael Niedermayer <mich...@niedermayer.cc> wrote: >> >> > Fixes: runtime error: shift exponent 4294967289 is too large for >> >> > 32-bit >> >> > type >> >> > 'int' >> >> > Fixes: 3030/clusterfuzz-testcase-minimized-4649809254285312 >> >> > >> >> > Found-by: continuous fuzzing process >> >> > https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg >> >> > Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> >> >> > --- >> >> > libavcodec/pixlet.c | 2 +- >> >> > 1 file changed, 1 insertion(+), 1 deletion(-) >> >> > >> >> > diff --git a/libavcodec/pixlet.c b/libavcodec/pixlet.c >> >> > index 088226bdda..a9cfe085c9 100644 >> >> > --- a/libavcodec/pixlet.c >> >> > +++ b/libavcodec/pixlet.c >> >> > @@ -262,7 +262,7 @@ static int read_high_coeffs(AVCodecContext >> >> > *avctx, >> >> > uint8_t *src, int16_t *dst, i >> >> > >> >> > flag = 0; >> >> > >> >> > - if (state * 4ULL > 0xFF || i >= size) >> >> > + if ((uint64_t)state > 0xFF / 4 || i >= size) >> >> >> >> This is not exact same behaviour. >> > >> > no, it differs for a small number of cases that have one of the 2 >> > most significant bits (of the 64 bits) set in state. >> > I think this was a bug i introduced in a previous commit. >> > >> > If above change is not the correct thing to do, please elaborate. >> > state is passed into ff_clz() later which has no deterministic >> > behavior when these MSBs are set as ff_clz() uses unsigned and state >> > is int64_t and unsigned can be 32 or 64bit. >> >> Only 32 bits matters for ff_clz() anyway. > > your reply is a bit terse. > Does that mean you have no objections to the patch ? > > about ff_clz(), with 64bit unsigned a ff_clz(1) should return 63, the > code looks like it expects 31
yes. > > [...] > -- > Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB > > If you fake or manipulate statistics in a paper in physics you will never > get a job again. > If you fake or manipulate statistics in a paper in medicin you will get > a job for life at the pharma industry. > _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
