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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org,
        "Alexander Aring" <alex.aring@gmail.com>,
        "Marcel Holtmann" <marcel@holtmann.org>
Date:   Sun, 09 Dec 2018 21:50:33 +0000
Message-ID: <lsq.1544392233.55747507@decadent.org.uk>
Subject: [PATCH 3.16 106/328] mac802154: tx: use put_unaligned_le16 for
 copy crc
In-Reply-To: <lsq.1544392232.713909046@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

3.16.62-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Alexander Aring <alex.aring@gmail.com>

commit 061ef8f915988839b12460c47ebfcf3700e124f0 upstream.

This patch replaces the memcpy with a put_unaligned_le16. The placement
of crc inside of PSDU can also be unaligned. With memcpy this can fail
on some architectures.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
Reported-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 net/mac802154/tx.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/net/mac802154/tx.c
+++ b/net/mac802154/tx.c
@@ -24,6 +24,7 @@
 #include <linux/netdevice.h>
 #include <linux/if_arp.h>
 #include <linux/crc-ccitt.h>
+#include <asm/unaligned.h>
 
 #include <net/ieee802154_netdev.h>
 #include <net/mac802154.h>
@@ -95,9 +96,9 @@ netdev_tx_t mac802154_tx(struct mac80215
 	mac802154_monitors_rx(mac802154_to_priv(&priv->hw), skb);
 
 	if (!(priv->hw.flags & IEEE802154_HW_OMIT_CKSUM)) {
-		__le16 crc = cpu_to_le16(crc_ccitt(0, skb->data, skb->len));
+		u16 crc = crc_ccitt(0, skb->data, skb->len);
 
-		memcpy(skb_put(skb, 2), &crc, 2);
+		put_unaligned_le16(crc, skb_put(skb, 2));
 	}
 
 	if (skb_cow_head(skb, priv->hw.extra_tx_headroom))