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

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
...@@ -208,7 +208,7 @@ static inline void mlx5e_insert_vlan(void *start, struct sk_buff *skb, u16 ihs) ...@@ -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 cpy1_sz = 2 * ETH_ALEN;
int cpy2_sz = ihs - cpy1_sz; 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_proto = skb->vlan_proto;
vhdr->h_vlan_TCI = cpu_to_be16(skb_vlan_tag_get(skb)); vhdr->h_vlan_TCI = cpu_to_be16(skb_vlan_tag_get(skb));
memcpy(&vhdr->h_vlan_encapsulated_proto, skb->data + cpy1_sz, cpy2_sz); memcpy(&vhdr->h_vlan_encapsulated_proto, skb->data + cpy1_sz, cpy2_sz);
......
...@@ -46,8 +46,10 @@ struct vlan_hdr { ...@@ -46,8 +46,10 @@ struct vlan_hdr {
* @h_vlan_encapsulated_proto: packet type ID or len * @h_vlan_encapsulated_proto: packet type ID or len
*/ */
struct vlan_ethhdr { struct vlan_ethhdr {
unsigned char h_dest[ETH_ALEN]; struct_group(addrs,
unsigned char h_source[ETH_ALEN]; unsigned char h_dest[ETH_ALEN];
unsigned char h_source[ETH_ALEN];
);
__be16 h_vlan_proto; __be16 h_vlan_proto;
__be16 h_vlan_TCI; __be16 h_vlan_TCI;
__be16 h_vlan_encapsulated_proto; __be16 h_vlan_encapsulated_proto;
......
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