Commit 6d1ccff6 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller

net: reset mac header in dev_start_xmit()

On 64 bit arches :

There is a off-by-one error in qdisc_pkt_len_init() because
mac_header is not set in xmit path.

skb_mac_header() returns an out of bound value that was
harmless because hdr_len is an 'unsigned int'

On 32bit arches, the error is abysmal.

This patch is also a prereq for "macvlan: add multicast filter"
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: Ben Greear <greearb@candelatech.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 12b0004d
...@@ -2835,6 +2835,8 @@ int dev_queue_xmit(struct sk_buff *skb) ...@@ -2835,6 +2835,8 @@ int dev_queue_xmit(struct sk_buff *skb)
struct Qdisc *q; struct Qdisc *q;
int rc = -ENOMEM; int rc = -ENOMEM;
skb_reset_mac_header(skb);
/* Disable soft irqs for various locks below. Also /* Disable soft irqs for various locks below. Also
* stops preemption for RCU. * stops preemption for RCU.
*/ */
......
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