Re: [PATCH for-next 1/2] RDMA/qedr: Notify user application if DPM is supported

[Leon Romanovsky <leon-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

[-- Attachment #1: Type: text/plain, Size: 1591 bytes --]

On Tue, Jun 20, 2017 at 08:34:24AM +0000, Amrani, Ram wrote:
> > Um, how is uapi compatibility achieved here? I don't see any size
> > tests related to qedr_alloc_ucontext_resp:
> >
> > struct ib_ucontext *qedr_alloc_ucontext(struct ib_device *ibdev,
> >                                         struct ib_udata *udata)
> > {
> >         struct qedr_alloc_ucontext_resp uresp;
> >         rc = ib_copy_to_udata(udata, &uresp, sizeof(uresp));
> >
> > Seems bad.
> >
> > Same with the other patch.
> >
> > Jason
>
> It does seem bad. Did you had in mind something like this:
>          struct qedr_alloc_ucontext_resp uresp;
>          size_t copy_size = min_t(size_t, sizeof(uresp), udata->outlen);
>
>          rc = ib_copy_to_udata(udata, &uresp, copy_size);
>
> If so, it makes sense to me to protect everybody's transactions.
> I.e.:
> 	static inline int ib_copy_to_udata(struct ib_udata *udata, void *src, size_t len)
> 	{
> 		size_t copy_size = min_t(size_t, sizeof(uresp), udata->outlen);
> 		return copy_to_user(udata->outbuf, src, copy_size) ? -EFAULT : 0;
> 	}
>
> Likewise, a protection can be added for ib_copy_from_udata() too.

mlx4 and mlx5 don't need such protection, because they calculates the
response length and ensure that no extra data is copied.

Thanks

>
> Let me know if I'm missing something. If not, I'll send a patch.
>
> Thanks,
> Ram
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-rdma" in
> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 833 bytes --]