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[v2,11/63] libertas_tf: Use struct_group() for memcpy() region

Message ID 20210818060533.3569517-12-keescook@chromium.org (mailing list archive)
State Not Applicable
Delegated to: Netdev Maintainers
Headers show
Series Introduce strict memcpy() bounds checking | expand

Checks

Context Check Description
netdev/cover_letter success Link
netdev/fixes_present success Link
netdev/patch_count fail Series longer than 15 patches
netdev/tree_selection success Guessed tree name to be net-next
netdev/subject_prefix success Link
netdev/cc_maintainers warning 3 maintainers not CCed: wanjiabing@vivo.com ndesaulniers@google.com nathan@kernel.org
netdev/source_inline success Was 0 now: 0
netdev/verify_signedoff success Link
netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 12 this patch: 12
netdev/kdoc success Errors and warnings before: 2 this patch: 2
netdev/verify_fixes success Link
netdev/checkpatch warning CHECK: Alignment should match open parenthesis
netdev/build_allmodconfig_warn success Errors and warnings before: 12 this patch: 12
netdev/header_inline success Link

Commit Message

Kees Cook Aug. 18, 2021, 6:04 a.m. UTC
In preparation for FORTIFY_SOURCE performing compile-time and run-time
field array 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 tx_dest_addr_high.

"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: Lee Jones <lee.jones@linaro.org>
Cc: YueHaibing <yuehaibing@huawei.com>
Cc: linux-wireless@vger.kernel.org
Cc: netdev@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/net/wireless/marvell/libertas_tf/libertas_tf.h | 10 ++++++----
 drivers/net/wireless/marvell/libertas_tf/main.c        |  3 ++-
 2 files changed, 8 insertions(+), 5 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/wireless/marvell/libertas_tf/libertas_tf.h b/drivers/net/wireless/marvell/libertas_tf/libertas_tf.h
index 5d726545d987..b2af2ddb6bc4 100644
--- a/drivers/net/wireless/marvell/libertas_tf/libertas_tf.h
+++ b/drivers/net/wireless/marvell/libertas_tf/libertas_tf.h
@@ -268,10 +268,12 @@  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_tf/main.c b/drivers/net/wireless/marvell/libertas_tf/main.c
index 71492211904b..02a1e1f547d8 100644
--- a/drivers/net/wireless/marvell/libertas_tf/main.c
+++ b/drivers/net/wireless/marvell/libertas_tf/main.c
@@ -232,7 +232,8 @@  static void lbtf_tx_work(struct work_struct *work)
 			     ieee80211_get_tx_rate(priv->hw, info)->hw_value);
 
 	/* copy destination address from 802.11 header */
-	memcpy(txpd->tx_dest_addr_high, skb->data + sizeof(struct txpd) + 4,
+	BUILD_BUG_ON(sizeof(txpd->tx_dest_addr) != ETH_ALEN);
+	memcpy(&txpd->tx_dest_addr, skb->data + sizeof(struct txpd) + 4,
 		ETH_ALEN);
 	txpd->tx_packet_length = cpu_to_le16(len);
 	txpd->tx_packet_location = cpu_to_le32(sizeof(struct txpd));