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From: Saeed Mahameed <saeed@kernel•org>
To: "David S. Miller" <davem@davemloft•net>,
	Jakub Kicinski <kuba@kernel•org>
Cc: netdev@vger•kernel.org, Kees Cook <keescook@chromium•org>,
	Saeed Mahameed <saeedm@nvidia•com>
Subject: [net 17/18] net/mlx5e: Use struct_group() for memcpy() region
Date: Tue,  1 Feb 2022 21:04:03 -0800	[thread overview]
Message-ID: <20220202050404.100122-18-saeed@kernel.org> (raw)
In-Reply-To: <20220202050404.100122-1-saeed@kernel.org>

From: Kees Cook <keescook@chromium•org>

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: 34802a42b352 ("net/mlx5e: Do not modify the TX SKB")
Signed-off-by: Kees Cook <keescook@chromium•org>
Signed-off-by: Saeed Mahameed <saeedm@nvidia•com>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_tx.c | 2 +-
 include/linux/if_vlan.h                         | 6 ++++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
index 7fd33b356cc8..ee7ecb88adc1 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tx.c
@@ -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);
diff --git a/include/linux/if_vlan.h b/include/linux/if_vlan.h
index 8420fe504927..2be4dd7e90a9 100644
--- a/include/linux/if_vlan.h
+++ b/include/linux/if_vlan.h
@@ -46,8 +46,10 @@ struct vlan_hdr {
  *	@h_vlan_encapsulated_proto: packet type ID or len
  */
 struct vlan_ethhdr {
-	unsigned char	h_dest[ETH_ALEN];
-	unsigned char	h_source[ETH_ALEN];
+	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;
-- 
2.34.1


  parent reply	other threads:[~2022-02-02  5:06 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-02  5:03 [pull request][net 00/18] mlx5 fixes 2022-02-01 Saeed Mahameed
2022-02-02  5:03 ` [net 01/18] net/mlx5: Bridge, take rtnl lock in init error handler Saeed Mahameed
2022-02-02 14:30   ` patchwork-bot+netdevbpf
2022-02-02  5:03 ` [net 02/18] net/mlx5: Bridge, ensure dev_name is null-terminated Saeed Mahameed
2022-02-02  5:03 ` [net 03/18] net/mlx5e: TC, Reject rules with drop and modify hdr action Saeed Mahameed
2022-02-02  5:03 ` [net 04/18] net/mlx5e: Fix module EEPROM query Saeed Mahameed
2022-02-02  5:03 ` [net 05/18] net/mlx5: Use del_timer_sync in fw reset flow of halting poll Saeed Mahameed
2022-02-02  5:03 ` [net 06/18] net/mlx5e: TC, Reject rules with forward and drop actions Saeed Mahameed
2022-02-02  5:03 ` [net 07/18] net/mlx5: Fix offloading with ESWITCH_IPV4_TTL_MODIFY_ENABLE Saeed Mahameed
2022-02-02  5:03 ` [net 08/18] net/mlx5: Bridge, Fix devlink deadlock on net namespace deletion Saeed Mahameed
2022-02-02  5:03 ` [net 09/18] net/mlx5e: Fix wrong calculation of header index in HW_GRO Saeed Mahameed
2022-02-02  5:03 ` [net 10/18] net/mlx5e: Fix broken SKB allocation in HW-GRO Saeed Mahameed
2022-02-02  5:03 ` [net 11/18] net/mlx5e: Fix handling of wrong devices during bond netevent Saeed Mahameed
2022-02-02  5:03 ` [net 12/18] net/mlx5: E-Switch, Fix uninitialized variable modact Saeed Mahameed
2022-02-02  5:03 ` [net 13/18] net/mlx5e: Don't treat small ceil values as unlimited in HTB offload Saeed Mahameed
2022-02-02  5:04 ` [net 14/18] net/mlx5e: IPsec: Fix crypto offload for non TCP/UDP encapsulated traffic Saeed Mahameed
2022-02-02  5:04 ` [net 15/18] net/mlx5e: IPsec: Fix tunnel mode crypto offload for non TCP/UDP traffic Saeed Mahameed
2022-02-02  5:04 ` [net 16/18] net/mlx5e: Avoid implicit modify hdr for decap drop rule Saeed Mahameed
2022-02-02  5:04 ` Saeed Mahameed [this message]
2022-02-02  5:04 ` [net 18/18] net/mlx5e: Avoid field-overflowing memcpy() Saeed Mahameed

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