On Fri, Mar 8, 2019 at 4:28 AM Michael Niedermayer <mich...@niedermayer.cc> wrote:
> On Thu, Mar 07, 2019 at 09:18:42PM +0100, Michael Niedermayer wrote: > > On Thu, Mar 07, 2019 at 09:45:12AM +0800, Jun Zhao wrote: > > > From: Jun Zhao <barryjz...@tencent.com> > > > > > > accumulation of 8-bits uint_8 (uint8_t *src) into 32-bits (uint32_t > *ii) > > > data type, it will have a risk of an integral value becoming larger > than > > > the 32-bits integer capacity and resulting in an integer overflow. For > > > this risk, add a checking with warning message. > > > > > > Signed-off-by: Jun Zhao <barryjz...@tencent.com> > > > --- > > > libavfilter/vf_nlmeans.c | 7 +++++++ > > > 1 files changed, 7 insertions(+), 0 deletions(-) > > > > > > diff --git a/libavfilter/vf_nlmeans.c b/libavfilter/vf_nlmeans.c > > > index dcb5a03..9876aae 100644 > > > --- a/libavfilter/vf_nlmeans.c > > > +++ b/libavfilter/vf_nlmeans.c > > > @@ -236,6 +236,13 @@ static void compute_ssd_integral_image(const > NLMeansDSPContext *dsp, > > > // adjusted end x position of the safe area after width of the > safe area gets aligned > > > const int endx_safe = startx_safe + safe_pw; > > > > > > + // accumulation of 8-bits uint_8 (uint8_t *src) into 32-bits > (uint32_t *ii) > > > + // data type, it will have a risk of an integral value becoming > larger than > > > + // the 32-bits integer capacity and resulting in an integer > overflow. > > > + if ((UINT32_MAX / (uint64_t)w) < (255 * (uint64_t)h)) > > > + av_log(NULL, AV_LOG_WARNING, > > > + "image (%d x %d) integral value may overflow.\n", w > ,h); > > > > Printing a warning is not an adequate response for a integer overflow. > > Such thing is undefined behavior (in case signed of signed int) and must > > not occur. > > And if no signed ints are involved, while this is then not undefined it > still > gives the wrong result. Thats a bug, the bug should be fixed not a warning > be printed that the bug might be triggered > > Thanks > > Will give a stricter w * h check for this case, Tks _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
