2010-12-22 09:14:52

by Johannes Berg

Subject: [PATCH 2.6.37] mac80211: fix mesh forwarding

From: Johannes Berg <[email protected]>

Under memory pressure, the mac80211 mesh code
may helpfully print a message that it failed
to clone a mesh frame and then will proceed
to crash trying to use it anyway. Fix that.

Cc: [email protected] [2.6.27+]
Signed-off-by: Johannes Berg <[email protected]>
---
net/mac80211/rx.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

--- wireless-testing.orig/net/mac80211/rx.c 2010-12-22 10:05:58.000000000 +0100
+++ wireless-testing/net/mac80211/rx.c 2010-12-22 10:06:08.000000000 +0100
@@ -1831,9 +1831,11 @@ ieee80211_rx_h_mesh_fwding(struct ieee80

fwd_skb = skb_copy(skb, GFP_ATOMIC);

- if (!fwd_skb && net_ratelimit())
+ if (!fwd_skb && net_ratelimit()) {
printk(KERN_DEBUG "%s: failed to clone mesh frame\n",
sdata->name);
+ goto out;
+ }

fwd_hdr = (struct ieee80211_hdr *) fwd_skb->data;
memcpy(fwd_hdr->addr2, sdata->vif.addr, ETH_ALEN);
@@ -1871,6 +1873,7 @@ ieee80211_rx_h_mesh_fwding(struct ieee80
}
}

+ out:
if (is_multicast_ether_addr(hdr->addr1) ||
sdata->dev->flags & IFF_PROMISC)
return RX_CONTINUE;

2010-12-22 18:22:30

by Javier Cardona

Subject: Re: [PATCH 2.6.37] mac80211: fix mesh forwarding

Johannes,

Had I encountered this I would have changed the "failed to clone mesh
frame" message to "I'm about to crash". Your fix is better.

Thanks!

On Wed, Dec 22, 2010 at 1:15 AM, Johannes Berg
<[email protected]> wrote:
> From: Johannes Berg <[email protected]>
>
> Under memory pressure, the mac80211 mesh code
> may helpfully print a message that it failed
> to clone a mesh frame and then will proceed
> to crash trying to use it anyway. Fix that.
>
> Cc: [email protected] [2.6.27+]
> Signed-off-by: Johannes Berg <[email protected]>
Acked-by: Javier Cardona <[email protected]>

> ---
> ?net/mac80211/rx.c | ? ?5 ++++-
> ?1 file changed, 4 insertions(+), 1 deletion(-)
>
> --- wireless-testing.orig/net/mac80211/rx.c ? ? 2010-12-22 10:05:58.000000000 +0100
> +++ wireless-testing/net/mac80211/rx.c ?2010-12-22 10:06:08.000000000 +0100
> @@ -1831,9 +1831,11 @@ ieee80211_rx_h_mesh_fwding(struct ieee80
>
> ? ? ? ? ? ? ? ? ? ? ? ?fwd_skb = skb_copy(skb, GFP_ATOMIC);
>
> - ? ? ? ? ? ? ? ? ? ? ? if (!fwd_skb && net_ratelimit())
> + ? ? ? ? ? ? ? ? ? ? ? if (!fwd_skb && net_ratelimit()) {
> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?printk(KERN_DEBUG "%s: failed to clone mesh frame\n",
> ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? sdata->name);
> + ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? goto out;
> + ? ? ? ? ? ? ? ? ? ? ? }
>
> ? ? ? ? ? ? ? ? ? ? ? ?fwd_hdr = ?(struct ieee80211_hdr *) fwd_skb->data;
> ? ? ? ? ? ? ? ? ? ? ? ?memcpy(fwd_hdr->addr2, sdata->vif.addr, ETH_ALEN);
> @@ -1871,6 +1873,7 @@ ieee80211_rx_h_mesh_fwding(struct ieee80
> ? ? ? ? ? ? ? ?}
> ? ? ? ?}
>
> + out:
> ? ? ? ?if (is_multicast_ether_addr(hdr->addr1) ||
> ? ? ? ? ? ?sdata->dev->flags & IFF_PROMISC)
> ? ? ? ? ? ? ? ?return RX_CONTINUE;
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-wireless" in
> the body of a message to [email protected]
> More majordomo info at ?http://vger.kernel.org/majordomo-info.html
>



--
Javier Cardona
cozybit Inc.
http://www.cozybit.com