On Sun, Feb 14, 2021 at 6:35 PM Anton Khirnov <an...@khirnov.net> wrote:
> Quoting Nuo Mi (2021-02-14 07:27:39) > > CC libavcodec/mpegaudiodec_common.o > > libavcodec/movtextenc.c: In function ‘mov_text_style_start’: > > libavcodec/movtextenc.c:358:26: warning: comparison is always false due > to limited range of data type [-Wtype-limits] > > 358 | if (s->count + 1 > SIZE_MAX / > sizeof(*s->style_attributes) || > > --- > > libavcodec/movtextenc.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/libavcodec/movtextenc.c b/libavcodec/movtextenc.c > > index 1bef21e0b9..cd0e43a79b 100644 > > --- a/libavcodec/movtextenc.c > > +++ b/libavcodec/movtextenc.c > > @@ -355,7 +355,7 @@ static int mov_text_style_start(MovTextContext *s) > > StyleBox *tmp; > > > > // last style != defaults, end the style entry and start a new > one > > - if (s->count + 1 > SIZE_MAX / sizeof(*s->style_attributes) || > > + if ((s->count + 1) * sizeof(*s->style_attributes) > SIZE_MAX || > > What guarantees the multiplication does not overflow? > Hi Anton, Thanks for the review. It never overflows on 64bits system. This why the compiler has warning on my 64 bits system. If you check https://github.com/FFmpeg/FFmpeg/blob/21346672270ae723aa774a9c8b0749954a75b3df/libavcodec/movtextenc.c#L110 s->count * sizeof(*s->style_attributes) never > 32 bits. I can add some check for s->count check based on the code if you are preferred. > -- > Anton Khirnov > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
