On Fri, 22 Jul 2022 at 06:11, Alexei Starovoitov
<alexei.starovoitov@xxxxxxxxx> wrote:
>
> On Thu, Jul 21, 2022 at 03:42:36PM +0200, Kumar Kartikeya Dwivedi wrote:
> > +/* Trusted arguments are those which are meant to be referenced arguments with
> > + * unchanged offset. It is used to enforce that pointers obtained from acquire
> > + * kfuncs remain unmodified when being passed to helpers taking trusted args.
> > + *
> > + * Consider
> > + * struct foo {
> > + * int data;
> > + * struct foo *next;
> > + * };
> > + *
> > + * struct bar {
> > + * int data;
> > + * struct foo f;
> > + * };
> > + *
> > + * struct foo *f = alloc_foo(); // Acquire kfunc
> > + * struct bar *b = alloc_bar(); // Acquire kfunc
> > + *
> > + * If a kfunc set_foo_data() wants to operate only on the allocated object, it
> > + * will set the KF_TRUSTED_ARGS flag, which will prevent unsafe usage like:
> > + *
> > + * set_foo_data(f, 42); // Allowed
> > + * set_foo_data(f->next, 42); // Rejected, non-referenced pointer
> > + * set_foo_data(&f->next, 42);// Rejected, referenced, but bad offset
> > + * set_foo_data(&b->f, 42); // Rejected, referenced, but wrong type
>
> I think you meant to swap above two comments ?
> That's what I did while applying.
>
> Also fixed typo in Fixes tag in patch 13. It was missing a letter in sha.
>
> Since there are 3 other pending patchsets in patchwork that add new kfuncs
> this cleanup of kfunc registration couldn't have come at better time.
>
> Thank you for doing this work.
Thank you for doing the fixups!
