Re: [PATCH] lib: do not call memcpy with sz zero and null pointer

[Henning Schild <henning.schild@siemens.com>]

Am Wed, 21 Sep 2022 15:06:12 +0200
schrieb Thomas Monjalon <thomas@monjalon.net>:

> 07/09/2022 17:05, Henning Schild:
> > There is no point in such a call and UBSan complains about a call to
> > memcpy with a null pointer as second arg.
> > 
> > When building with -Db_sanitize=undefined, Clang gives the following
> > warning
> > ../lib/bpf/bpf_load.c:37:20: runtime error: null pointer passed as
> > 	argument 2, which is declared to never be null
> > 
> > A check of the sz before calling memcpy fixes that.
> > 
> > Signed-off-by: Henning Schild <henning.schild@siemens.com>
> > ---
> > --- a/lib/bpf/bpf_load.c
> > +++ b/lib/bpf/bpf_load.c
> > @@ -34,7 +34,8 @@ bpf_load(const struct rte_bpf_prm *prm)
> >  
> >  	memcpy(&bpf->prm, prm, sizeof(bpf->prm));
> >  
> > -	memcpy(buf + bsz, prm->xsym, xsz);
> > +	if (xsz)
> > +		memcpy(buf + bsz, prm->xsym, xsz);*  
> 
> I assume I can safely change it to
> 	if (xsz > 0)
> to comply with the code style.

Sure, thanks!

Henning

> 
> Applied, thanks.
> 
>