Hi, On Fri, May 26, 2017 at 5:50 PM, Michael Niedermayer <mich...@niedermayer.cc > wrote:
> On Fri, May 26, 2017 at 11:18:12PM +0200, Hendrik Leppkes wrote: > > On Fri, May 26, 2017 at 11:11 PM, Michael Niedermayer > > <mich...@niedermayer.cc> wrote: > > > On Fri, May 26, 2017 at 03:20:14PM +0100, Rostislav Pehlivanov wrote: > > >> On 26 May 2017 at 12:21, wm4 <nfx...@googlemail.com> wrote: > > >> > > >> > On Thu, 25 May 2017 16:10:49 +0200 > > >> > Michael Niedermayer <mich...@niedermayer.cc> wrote: > > >> > > > >> > > Fixes: 1735/clusterfuzz-testcase-minimized-5350472347025408 > > >> > > > > >> > > Found-by: continuous fuzzing process > https://github.com/google/oss- > > >> > fuzz/tree/master/projects/ffmpeg > > >> > > Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> > > >> > > --- > > >> > > libavcodec/fft_template.c | 50 +++++++++++++++++++++++------- > > >> > ----------------- > > >> > > 1 file changed, 25 insertions(+), 25 deletions(-) > > >> > > > > >> > > diff --git a/libavcodec/fft_template.c b/libavcodec/fft_template.c > > >> > > index 480557f49f..e3a37e5d69 100644 > > >> > > --- a/libavcodec/fft_template.c > > >> > > +++ b/libavcodec/fft_template.c > > >> > > @@ -249,7 +249,7 @@ static void fft_calc_c(FFTContext *s, > FFTComplex *z) > > >> > { > > >> > > > > >> > > int nbits, i, n, num_transforms, offset, step; > > >> > > int n4, n2, n34; > > >> > > - FFTSample tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7, tmp8; > > >> > > + SUINT tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7, tmp8; > > >> > > > >> > I want this SUINT thing gone, not have more of it. > > >> > _______________________________________________ > > >> > ffmpeg-devel mailing list > > >> > ffmpeg-devel@ffmpeg.org > > >> > http://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > >> > > > >> > > >> I agree, especially here. > > > > > >> Overflows should be left to happen in transforms if the input is > corrupt. > > > > > > signed int overflow is not allowed in C, if that is what you meant. > > > > > > > > > > Its "undefined", which means what the result will be is not defined - > > which in such a DSP function is irrelevant, if all it causes is > > corrupt output ... from corrupt input. > > no, this is not correct. > undefined behavior does not mean the effect will be limited to > the output. > It could cause the process to hard lockup, trigger an exception or > set a flag causing errors in later unrelated code. We've discussed this before, if you believe this to be exploitable, why allow it in our repository at all? I know of no other project that even remotely allows such ridiculous things. Please limit exploitable code to your personal tree, ffmpeg is not a rootkit. Ronald _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
