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 txpd around members tx_dest_addr_high and tx_dest_addr_low 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 queue_id.
"pahole" shows no size nor member offset changes to struct txpd. "objdump -d" shows no object code changes.
Signed-off-by: Kees Cook keescook@chromium.org --- drivers/net/wireless/marvell/libertas/host.h | 10 ++++++---- drivers/net/wireless/marvell/libertas/tx.c | 5 +++-- 2 files changed, 9 insertions(+), 6 deletions(-)
diff --git a/drivers/net/wireless/marvell/libertas/host.h b/drivers/net/wireless/marvell/libertas/host.h index dfa22468b14a..af96bdba3b2b 100644 --- a/drivers/net/wireless/marvell/libertas/host.h +++ b/drivers/net/wireless/marvell/libertas/host.h @@ -308,10 +308,12 @@ struct txpd { __le32 tx_packet_location; /* Tx packet length */ __le16 tx_packet_length; - /* First 2 byte of destination MAC address */ - u8 tx_dest_addr_high[2]; - /* Last 4 byte of destination MAC address */ - u8 tx_dest_addr_low[4]; + struct_group(tx_dest_addr, + /* First 2 byte of destination MAC address */ + u8 tx_dest_addr_high[2]; + /* Last 4 byte of destination MAC address */ + u8 tx_dest_addr_low[4]; + ); /* Pkt Priority */ u8 priority; /* Pkt Trasnit Power control */ diff --git a/drivers/net/wireless/marvell/libertas/tx.c b/drivers/net/wireless/marvell/libertas/tx.c index aeb481740df6..27304a98787d 100644 --- a/drivers/net/wireless/marvell/libertas/tx.c +++ b/drivers/net/wireless/marvell/libertas/tx.c @@ -113,6 +113,7 @@ netdev_tx_t lbs_hard_start_xmit(struct sk_buff *skb, struct net_device *dev) p802x_hdr = skb->data; pkt_len = skb->len;
+ BUILD_BUG_ON(sizeof(txpd->tx_dest_addr) != ETH_ALEN); if (priv->wdev->iftype == NL80211_IFTYPE_MONITOR) { struct tx_radiotap_hdr *rtap_hdr = (void *)skb->data;
@@ -124,10 +125,10 @@ netdev_tx_t lbs_hard_start_xmit(struct sk_buff *skb, struct net_device *dev) pkt_len -= sizeof(*rtap_hdr);
/* copy destination address from 802.11 header */ - memcpy(txpd->tx_dest_addr_high, p802x_hdr + 4, ETH_ALEN); + memcpy(&txpd->tx_dest_addr, p802x_hdr + 4, ETH_ALEN); } else { /* copy destination address from 802.3 header */ - memcpy(txpd->tx_dest_addr_high, p802x_hdr, ETH_ALEN); + memcpy(&txpd->tx_dest_addr, p802x_hdr, ETH_ALEN); }
txpd->tx_packet_length = cpu_to_le16(pkt_len);