Re: [PATCH 19/64] ip: Use struct_group() for memcpy() regions

Kees Cook
2021-07-28T21:01:35Z

On Wed, Jul 28, 2021 at 07:55:53AM +0200, Greg Kroah-Hartman wrote:
> > struct ethhdr {
> > - unsigned char h_dest[ETH_ALEN]; /* destination eth addr */
> > - unsigned char h_source[ETH_ALEN]; /* source ether addr */
> > + union {
> > + struct {
> > + unsigned char h_dest[ETH_ALEN]; /* destination eth addr */
> > + unsigned char h_source[ETH_ALEN]; /* source ether addr */
> > + };
> > + struct {
> > + unsigned char h_dest[ETH_ALEN]; /* destination eth addr */
> > + unsigned char h_source[ETH_ALEN]; /* source ether addr */
> > + } addrs;
>
> A union of the same fields in the same structure in the same way?
>
> Ah, because struct_group() can not be used here? Still feels odd to see
> in a userspace-visible header.

Yeah, there is some inconsistency here. I will clean this up for v2.

Is there a place we can put kernel-specific macros for use in UAPI
headers? (I need to figure out where things like __kernel_size_t get
defined...)

--
Kees Cook