[PATCH 2.4.26-pre1] Allow ebtables module to change protocol in netif_receive_skb

Currently skb->protocol is read before the bridge is called, even though
it's not used until after. Hence if an ebtables module changes the
protocol of a frame the wrong protocol is interpreted.

Simon Barber

--- linux-2.4.26-pre1.orig/net/core/dev.c	2004-02-25

04:16:33.000000000 -0800

+++ linux-2.4.26-pre1/net/core/dev.c	2004-02-25 06:42:05.000000000
-0800

@@ -1462,7 +1462,7 @@
 {
 	struct packet_type *ptype, *pt_prev;
 	int ret = NET_RX_DROP;
-	unsigned short type = skb->protocol;
+	unsigned short type;
 
 	if (skb->stamp.tv_sec == 0)
 		do_gettimeofday(&skb->stamp);

@@ -1507,6 +1507,7 @@
 	}
 #endif
 
+	type = skb->protocol;
 	for (ptype=ptype_base[ntohs(type)&15];ptype;ptype=ptype->next) {
 		if (ptype->type == type &&
 		    (!ptype->dev || ptype->dev == skb->dev)) {

On Wed, 25 Feb 2004 14:47:41 -0800
"Simon Barber" [off-list ref] wrote:

Currently skb->protocol is read before the bridge is called, even though
it's not used until after. Hence if an ebtables module changes the
protocol of a frame the wrong protocol is interpreted.

Applied, even though ebtables is not in 2.4.x yet the change is valid.
I've applied your 2.6.x variant too of course.

Thanks Simon.