Re: [RFC bpf-next 1/2] bpf: tnums: warn against the usage of tnum_in(tnum_range(), ...)

[Daniel Borkmann]

On 9/2/22 5:52 AM, Shung-Hsi Yu wrote:
> On Thu, Sep 01, 2022 at 05:00:58PM +0200, Daniel Borkmann wrote:
> > On 8/31/22 5:19 AM, Shung-Hsi Yu wrote:
> > > Commit a657182a5c51 ("bpf: Don't use tnum_range on array range checking
> > > for poke descriptors") has shown that using tnum_range() as argument to
> > > tnum_in() can lead to misleading code that looks like tight bound check
> > > when in fact the actual allowed range is much wider.
> > >
> > > Document such behavior to warn against its usage in general, and suggest
> > > some scenario where result can be trusted.
> > >
> > > Link: https://lore.kernel.org/bpf/984b37f9fdf7ac36831d2137415a4a915744c1b6.1661462653.git.daniel@xxxxxxxxxxxxx/
> > > Link: https://www.openwall.com/lists/oss-security/2022/08/26/1
> > > Signed-off-by: Shung-Hsi Yu <shung-hsi.yu@xxxxxxxx>
> >
> > Any objections from your side if I merge this? Thanks for adding doc. :)
>
> There is a small typo I meant to fix with s/including/include below.
>
> Other than that, none at all, thanks! :)

Fixed up and applied to bpf-next, thanks!