Re: [PATCH bpf-next v2 2/6] bpf: Add a ARG_PTR_TO_CONST_STR argument type

[Florent Revest]

On Fri, Mar 26, 2021 at 11:23 PM Andrii Nakryiko
<andrii.nakryiko@xxxxxxxxx> wrote:
> On Tue, Mar 23, 2021 at 7:23 PM Florent Revest <revest@xxxxxxxxxxxx> wrote:
> > +
> > +               map_off = reg->off + reg->var_off.value;
> > +               err = map->ops->map_direct_value_addr(map, &map_addr, map_off);
> > +               if (err)
> > +                       return err;
> > +
> > +               str_ptr = (char *)(long)(map_addr);
> > +               if (!strnchr(str_ptr + map_off,
> > +                            map->value_size - reg->off - map_off, 0))
>
> you are double subtracting reg->off here. isn't map->value_size -
> map_off what you want?

Good catch!

> > +                       verbose(env, "string is not zero-terminated\n");
>
> I'd prefer `return -EINVAL;`, but at least set err, otherwise what's the point?

Ah yeah, absolutely.