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[v2,10/63] libertas: Use struct_group() for memcpy() region

Message ID 20210818060533.3569517-11-keescook@chromium.org (mailing list archive)
State New, archived
Headers show
Series Introduce strict memcpy() bounds checking | expand

Commit Message

Kees Cook Aug. 18, 2021, 6:04 a.m. UTC 
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.

Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: libertas-dev@lists.infradead.org
Cc: linux-wireless@vger.kernel.org
Cc: netdev@vger.kernel.org
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(-)
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Patch

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);