Commit 6d5c900e authored by Kees Cook's avatar Kees Cook Committed by Saeed Mahameed
Browse files

net/mlx5e: Use struct_group() for memcpy() region 



In preparation for FORTIFY_SOURCE performing compile-time and run-time
field bounds checking for memcpy(), memmove(), and memset(), avoid
intentionally writing across neighboring fields.

Use struct_group() in struct vlan_ethhdr around members h_dest and
h_source, so they can be referenced together. This will allow memcpy()
and sizeof() to more easily reason about sizes, improve readability,
and avoid future warnings about writing beyond the end of h_dest.

"pahole" shows no size nor member offset changes to struct vlan_ethhdr.
"objdump -d" shows no object code changes.

Fixes: 34802a42 ("net/mlx5e: Do not modify the TX SKB")
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Signed-off-by: default avatarSaeed Mahameed <saeedm@nvidia.com>
parent 5b209d1a

drivers/net/ethernet/mellanox/mlx5/core/en_tx.c

+1 −1
Original line number Diff line number Diff line
@@ -208,7 +208,7 @@ static inline void mlx5e_insert_vlan(void *start, struct sk_buff *skb, u16 ihs) 
	int cpy1_sz = 2 * ETH_ALEN;

	int cpy2_sz = ihs - cpy1_sz;



	memcpy(vhdr, skb->data, cpy1_sz);

	memcpy(&vhdr->addrs, skb->data, cpy1_sz);

	vhdr->h_vlan_proto = skb->vlan_proto;

	vhdr->h_vlan_TCI = cpu_to_be16(skb_vlan_tag_get(skb));

	memcpy(&vhdr->h_vlan_encapsulated_proto, skb->data + cpy1_sz, cpy2_sz);

include/linux/if_vlan.h

+4 −2
Original line number Diff line number Diff line
@@ -46,8 +46,10 @@ struct vlan_hdr { 
 *	@h_vlan_encapsulated_proto: packet type ID or len

 */

struct vlan_ethhdr {

	struct_group(addrs,

		unsigned char	h_dest[ETH_ALEN];

		unsigned char	h_source[ETH_ALEN];

	);

	__be16		h_vlan_proto;

	__be16		h_vlan_TCI;

	__be16		h_vlan_encapsulated_proto;