[FFmpeg-devel] [PATCH] avutil/imgutils: av_image_check_size2() ensure width and height fit in 32bit

[Paul B Mahol]

On Wed, Jul 10, 2024 at 12:00 AM Michael Niedermayer <michael at niedermayer.cc>
wrote:

> On Tue, Jul 09, 2024 at 05:14:37PM +0200, Anton Khirnov wrote:
> > Quoting Michael Niedermayer (2024-07-09 15:28:10)
> > > On Tue, Jul 09, 2024 at 03:17:58PM +0200, Anton Khirnov wrote:
> > > > > ensure width and height fit in 32bit
> > > >
> > > > why?
> > >
> > > because not everyone wants undefined behavior
> > > because not everyone wants security issues
> > > because we dont support width and height > 32bit and its easier to
> check in a central place
> > > because the changed codes purpose is to check if the image paramaters
> are
> > >     within what we support, and width of 100 billion is not. You can
> try
> > >     all encoders with 100billion width. Then try to decode.
> > >     Iam curious, how many work, how many fail and how they fail
> > >     how many invalid bitstreams with no warning, how many undefined
> behaviors, ...
> > >
> > > Simply building FFmpeg on a platform with 64bit ints doesnt update
> > > ISO and ITU standards to allow larger values
> >
> > Quoting Michael Niedermayer (2020-10-07 16:45:56):
> > > At least in code i wrote and write i consider it a bug if it would
> > > assume sizeof(int/unsigned) == 4
> >
> > Make up your mind.
>
> Where do you see a contradiction ?
>
> 2020: assuming sizeof(int/unsigned) == 4 is a bug
> 2024: we do not support more than 32bit width and height,
>       nor is that supported by the majority of codec bitsterams and formats
>       -> We thus should in a central place check that instead of generating
>       undefined behavior and security issues
>
> What i suggest IS actually fixing a "sizeof(int/unsigned) == 4" bug
>
> If someone wants to make the codebase work with 64bit width and height,
> this
> should not be limited to "int is 64bit" systems that would be a very
> seriously
> broken design and also very illogic.
>
> Also your terse replies feel a bit rude
>

One can not simply reason with toxic humanoids.


>
> thx
>
> [...]
> --
> Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
>
> No great genius has ever existed without some touch of madness. --
> Aristotle
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>
> To unsubscribe, visit link above, or email
> ffmpeg-devel-request at ffmpeg.org with subject "unsubscribe".
>