[Linux-ATM-General] [Patch 3/3 v1] atm: br2684: Avoid alignment issues

[Pascal H. <pa...@pl...>]

Use memcmp() instead of cast to u16 when checking the PAD field.

Signed-off-by: Pascal Hambourg <pa...@pl...>
---
 net/atm/br2684.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff -uprN a/net/atm/br2684.c b/net/atm/br2684.c
--- a/net/atm/br2684.c	2011-08-16 22:13:47.000000000 +0200
+++ b/net/atm/br2684.c	2011-08-16 22:13:49.000000000 +0200
@@ -53,6 +53,7 @@ static const unsigned char ethertype_ipv
 static const unsigned char ethertype_ipv6[] = { ETHERTYPE_IPV6 };
 static const unsigned char llc_oui_pid_pad[] =
 			{ LLC, SNAP_BRIDGED, PID_ETHERNET, PAD_BRIDGED };
+static const unsigned char pad[] = { PAD_BRIDGED };
 static const unsigned char llc_oui_ipv4[] = { LLC, SNAP_ROUTED, ETHERTYPE_IPV4 };
 static const unsigned char llc_oui_ipv6[] = { LLC, SNAP_ROUTED, ETHERTYPE_IPV6 };

@@ -434,7 +435,7 @@ static void br2684_push(struct atm_vcc *
 			 */
 			if ((skb->len >= sizeof(llc_oui_pid_pad) + ETH_HLEN) &&
 			    (memcmp(skb->data, llc_oui_pid_pad, 7) == 0) &&
-			    (*((u16 *) (skb->data + 8)) == 0)) {
+			    (memcmp(skb->data + 8, pad, BR2684_PAD_LEN) == 0)) {
 				if (skb->data[7] == 0x01 &&
 				    skb->len >= sizeof(llc_oui_pid_pad) + ETH_ZLEN + ETH_FCS_LEN)
 					__skb_trim(skb, skb->len - ETH_FCS_LEN); /* trim FCS */
@@ -464,7 +465,7 @@ static void br2684_push(struct atm_vcc *
 		} else { /* p_bridged */
 			/* first 2 chars should be 0 */
 			if (skb->len < BR2684_PAD_LEN + ETH_HLEN ||
-			    *((u16 *) (skb->data)) != 0)
+			    memcmp(skb->data, pad, BR2684_PAD_LEN) != 0)
 				goto error;
 			skb_pull(skb, BR2684_PAD_LEN);
 			skb->protocol = eth_type_trans(skb, net_dev);